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Groups > linux.kernel > #1439225 > unrolled thread

[PATCH 00/34] Move LRU page reclaim from zones to nodes v9

Started byMel Gorman <mgorman@techsingularity.net>
First post2016-07-08 11:40 +0200
Last post2016-07-08 11:50 +0200
Articles 20 on this page of 27 — 1 participant

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Contents

  [PATCH 00/34] Move LRU page reclaim from zones to nodes v9 Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 09/34] mm, vmscan: simplify the logic deciding whether kswapd sleeps Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 01/34] mm, vmstat: add infrastructure for per-node vmstats Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 13/34] mm, vmscan: make shrink_node decisions more node-centric Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 16/34] mm, page_alloc: consider dirtyable memory in terms of nodes Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 20/34] mm: move vmscan writes and file write accounting to the node Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 12/34] mm: vmscan: do not reclaim from kswapd if there is any eligible zone Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 24/34] mm, vmscan: avoid passing in classzone_idx unnecessarily to shrink_node Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 14/34] mm, memcg: move memcg limit enforcement from zones to nodes Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 04/34] mm, mmzone: clarify the usage of zone padding Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 02/34] mm, vmscan: move lru_lock to the node Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 15/34] mm, workingset: make working set detection node-aware Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 23/34] mm: convert zone_reclaim to node_reclaim Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:40 +0200
    [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 30/34] mm: page_alloc: cache the last node whose dirty limit is reached Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 31/34] mm: vmstat: replace __count_zone_vm_events with a zone id equivalent Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 34/34] mm, vmstat: remove zone and node double accounting by approximating retries Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 10/34] mm, vmscan: by default have direct reclaim only shrink once per node Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 32/34] mm: vmstat: account per-zone stalls and pages skipped during reclaim Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 25/34] mm, vmscan: avoid passing in classzone_idx unnecessarily to compaction_ready Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 28/34] mm, vmscan: add classzone information to tracepoints Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 27/34] mm, vmscan: Have kswapd reclaim from all zones if reclaiming and buffer_heads_over_limit Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 26/34] mm, vmscan: avoid passing in remaining unnecessarily to prepare_kswapd_sleep Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 29/34] mm, page_alloc: remove fair zone allocation policy Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 22/34] mm, page_alloc: wake kswapd based on the highest eligible zone Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 33/34] mm, vmstat: print node-based stats in zoneinfo file Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200
    [PATCH 19/34] mm: move most file-based accounting to the node Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 11:50 +0200

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#1439225 — [PATCH 00/34] Move LRU page reclaim from zones to nodes v9

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 00/34] Move LRU page reclaim from zones to nodes v9
Message-ID<rSAqm-2Tv-3@gated-at.bofh.it>
Minor changes this time

Changelog since v8
o Cosmetic cleanups to comments
o Calculate node vmstat threshold based on the largest zone in the node
o Align retry checks with decisions made by the OOM killer
o Avoid tricks with -1 and kswapd_classzone_idx
o More consistent handling of buffer_heads_over_limit

Changelog since v7
o Rebase onto current mmots
o Avoid double accounting of stats in node and zone
o Kswapd will avoid more reclaim if an eligible zone is available
o Remove some duplications of sc->reclaim_idx and classzone_idx
o Print per-node stats in zoneinfo

Changelog since v6
o Correct reclaim_idx when direct reclaiming for memcg
o Also account LRU pages per zone for compaction/reclaim
o Add page_pgdat helper with more efficient lookup
o Init pgdat LRU lock only once
o Slight optimisation to wake_all_kswapds
o Always wake kcompactd when kswapd is going to sleep
o Rebase to mmotm as of June 15th, 2016

Changelog since v5
o Rebase and adjust to changes

Changelog since v4
o Rebase on top of v3 of page allocator optimisation series

Changelog since v3
o Rebase on top of the page allocator optimisation series
o Remove RFC tag

This is the latest version of a series that moves LRUs from the zones to
the node that is based upon 4.7-rc4 with Andrew's tree applied. While this
is a current rebase, the test results were based on mmotm as of June 23rd.
Conceptually, this series is simple but there are a lot of details. Some
of the broad motivations for this are;

1. The residency of a page partially depends on what zone the page was
   allocated from.  This is partially combatted by the fair zone allocation
   policy but that is a partial solution that introduces overhead in the
   page allocator paths.

2. Currently, reclaim on node 0 behaves slightly different to node 1. For
   example, direct reclaim scans in zonelist order and reclaims even if
   the zone is over the high watermark regardless of the age of pages
   in that LRU. Kswapd on the other hand starts reclaim on the highest
   unbalanced zone. A difference in distribution of file/anon pages due
   to when they were allocated results can result in a difference in 
   again. While the fair zone allocation policy mitigates some of the
   problems here, the page reclaim results on a multi-zone node will
   always be different to a single-zone node.
   it was scheduled on as a result.

3. kswapd and the page allocator scan zones in the opposite order to
   avoid interfering with each other but it's sensitive to timing.  This
   mitigates the page allocator using pages that were allocated very recently
   in the ideal case but it's sensitive to timing. When kswapd is allocating
   from lower zones then it's great but during the rebalancing of the highest
   zone, the page allocator and kswapd interfere with each other. It's worse
   if the highest zone is small and difficult to balance.

4. slab shrinkers are node-based which makes it harder to identify the exact
   relationship between slab reclaim and LRU reclaim.

The reason we have zone-based reclaim is that we used to have
large highmem zones in common configurations and it was necessary
to quickly find ZONE_NORMAL pages for reclaim. Today, this is much
less of a concern as machines with lots of memory will (or should) use
64-bit kernels. Combinations of 32-bit hardware and 64-bit hardware are
rare. Machines that do use highmem should have relatively low highmem:lowmem
ratios than we worried about in the past.

Conceptually, moving to node LRUs should be easier to understand. The
page allocator plays fewer tricks to game reclaim and reclaim behaves
similarly on all nodes. 

The series has been tested on a 16 core UMA machine and a 2-socket 48
core NUMA machine. The UMA results are presented in most cases as the NUMA
machine behaved similarly.

pagealloc
---------

This is a microbenchmark that shows the benefit of removing the fair zone
allocation policy. It was tested uip to order-4 but only orders 0 and 1 are
shown as the other orders were comparable.

                                           4.7.0-rc4                  4.7.0-rc4
                                      mmotm-20160623                 nodelru-v9
Min      total-odr0-1               490.00 (  0.00%)           457.00 (  6.73%)
Min      total-odr0-2               347.00 (  0.00%)           329.00 (  5.19%)
Min      total-odr0-4               288.00 (  0.00%)           273.00 (  5.21%)
Min      total-odr0-8               251.00 (  0.00%)           239.00 (  4.78%)
Min      total-odr0-16              234.00 (  0.00%)           222.00 (  5.13%)
Min      total-odr0-32              223.00 (  0.00%)           211.00 (  5.38%)
Min      total-odr0-64              217.00 (  0.00%)           208.00 (  4.15%)
Min      total-odr0-128             214.00 (  0.00%)           204.00 (  4.67%)
Min      total-odr0-256             250.00 (  0.00%)           230.00 (  8.00%)
Min      total-odr0-512             271.00 (  0.00%)           269.00 (  0.74%)
Min      total-odr0-1024            291.00 (  0.00%)           282.00 (  3.09%)
Min      total-odr0-2048            303.00 (  0.00%)           296.00 (  2.31%)
Min      total-odr0-4096            311.00 (  0.00%)           309.00 (  0.64%)
Min      total-odr0-8192            316.00 (  0.00%)           314.00 (  0.63%)
Min      total-odr0-16384           317.00 (  0.00%)           315.00 (  0.63%)
Min      total-odr1-1               742.00 (  0.00%)           712.00 (  4.04%)
Min      total-odr1-2               562.00 (  0.00%)           530.00 (  5.69%)
Min      total-odr1-4               457.00 (  0.00%)           433.00 (  5.25%)
Min      total-odr1-8               411.00 (  0.00%)           381.00 (  7.30%)
Min      total-odr1-16              381.00 (  0.00%)           356.00 (  6.56%)
Min      total-odr1-32              372.00 (  0.00%)           346.00 (  6.99%)
Min      total-odr1-64              372.00 (  0.00%)           343.00 (  7.80%)
Min      total-odr1-128             375.00 (  0.00%)           351.00 (  6.40%)
Min      total-odr1-256             379.00 (  0.00%)           351.00 (  7.39%)
Min      total-odr1-512             385.00 (  0.00%)           355.00 (  7.79%)
Min      total-odr1-1024            386.00 (  0.00%)           358.00 (  7.25%)
Min      total-odr1-2048            390.00 (  0.00%)           362.00 (  7.18%)
Min      total-odr1-4096            390.00 (  0.00%)           362.00 (  7.18%)
Min      total-odr1-8192            388.00 (  0.00%)           363.00 (  6.44%)

This shows a steady improvement throughout. The primary benefit is from
reduced system CPU usage which is obvious from the overall times;

           4.7.0-rc4   4.7.0-rc4
        mmotm-20160623nodelru-v8
User          189.19      191.80
System       2604.45     2533.56
Elapsed      2855.30     2786.39

The vmstats also showed that the fair zone allocation policy was definitely
removed as can be seen here;


                             4.7.0-rc3   4.7.0-rc3
                         mmotm-20160623 nodelru-v8
DMA32 allocs               28794729769           0
Normal allocs              48432501431 77227309877
Movable allocs                       0           0

tiobench on ext4
----------------

tiobench is a benchmark that artifically benefits if old pages remain resident
while new pages get reclaimed. The fair zone allocation policy mitigates this
problem so pages age fairly. While the benchmark has problems, it is important
that tiobench performance remains constant as it implies that page aging
problems that the fair zone allocation policy fixes are not re-introduced.

                                         4.7.0-rc4             4.7.0-rc4
                                    mmotm-20160623            nodelru-v9
Min      PotentialReadSpeed        89.65 (  0.00%)       90.21 (  0.62%)
Min      SeqRead-MB/sec-1          82.68 (  0.00%)       82.01 ( -0.81%)
Min      SeqRead-MB/sec-2          72.76 (  0.00%)       72.07 ( -0.95%)
Min      SeqRead-MB/sec-4          75.13 (  0.00%)       74.92 ( -0.28%)
Min      SeqRead-MB/sec-8          64.91 (  0.00%)       65.19 (  0.43%)
Min      SeqRead-MB/sec-16         62.24 (  0.00%)       62.22 ( -0.03%)
Min      RandRead-MB/sec-1          0.88 (  0.00%)        0.88 (  0.00%)
Min      RandRead-MB/sec-2          0.95 (  0.00%)        0.92 ( -3.16%)
Min      RandRead-MB/sec-4          1.43 (  0.00%)        1.34 ( -6.29%)
Min      RandRead-MB/sec-8          1.61 (  0.00%)        1.60 ( -0.62%)
Min      RandRead-MB/sec-16         1.80 (  0.00%)        1.90 (  5.56%)
Min      SeqWrite-MB/sec-1         76.41 (  0.00%)       76.85 (  0.58%)
Min      SeqWrite-MB/sec-2         74.11 (  0.00%)       73.54 ( -0.77%)
Min      SeqWrite-MB/sec-4         80.05 (  0.00%)       80.13 (  0.10%)
Min      SeqWrite-MB/sec-8         72.88 (  0.00%)       73.20 (  0.44%)
Min      SeqWrite-MB/sec-16        75.91 (  0.00%)       76.44 (  0.70%)
Min      RandWrite-MB/sec-1         1.18 (  0.00%)        1.14 ( -3.39%)
Min      RandWrite-MB/sec-2         1.02 (  0.00%)        1.03 (  0.98%)
Min      RandWrite-MB/sec-4         1.05 (  0.00%)        0.98 ( -6.67%)
Min      RandWrite-MB/sec-8         0.89 (  0.00%)        0.92 (  3.37%)
Min      RandWrite-MB/sec-16        0.92 (  0.00%)        0.93 (  1.09%)

           4.7.0-rc4   4.7.0-rc4
        mmotm-20160623 approx-v9
User          645.72      525.90
System        403.85      331.75
Elapsed      6795.36     6783.67

This shows that the series has little or not impact on tiobench which is
desirable and a reduction in system CPU usage. It indicates that the fair
zone allocation policy was removed in a manner that didn't reintroduce
one class of page aging bug. There were only minor differences in overall
reclaim activity

                             4.7.0-rc4   4.7.0-rc4
                          mmotm-20160623nodelru-v8
Minor Faults                    645838      647465
Major Faults                       573         640
Swap Ins                             0           0
Swap Outs                            0           0
DMA allocs                           0           0
DMA32 allocs                  46041453    44190646
Normal allocs                 78053072    79887245
Movable allocs                       0           0
Allocation stalls                   24          67
Stall zone DMA                       0           0
Stall zone DMA32                     0           0
Stall zone Normal                    0           2
Stall zone HighMem                   0           0
Stall zone Movable                   0          65
Direct pages scanned             10969       30609
Kswapd pages scanned          93375144    93492094
Kswapd pages reclaimed        93372243    93489370
Direct pages reclaimed           10969       30609
Kswapd efficiency                  99%         99%
Kswapd velocity              13741.015   13781.934
Direct efficiency                 100%        100%
Direct velocity                  1.614       4.512
Percentage direct scans             0%          0%

kswapd activity was roughly comparable. There were differences in direct
reclaim activity but negligible in the context of the overall workload
(velocity of 4 pages per second with the patches applied, 1.6 pages per
second in the baseline kernel).

pgbench read-only large configuration on ext4
---------------------------------------------

pgbench is a database benchmark that can be sensitive to page reclaim
decisions. This also checks if removing the fair zone allocation policy
is safe

pgbench Transactions
                        4.7.0-rc4             4.7.0-rc4
                   mmotm-20160623            nodelru-v8
Hmean    1       188.26 (  0.00%)      189.78 (  0.81%)
Hmean    5       330.66 (  0.00%)      328.69 ( -0.59%)
Hmean    12      370.32 (  0.00%)      380.72 (  2.81%)
Hmean    21      368.89 (  0.00%)      369.00 (  0.03%)
Hmean    30      382.14 (  0.00%)      360.89 ( -5.56%)
Hmean    32      428.87 (  0.00%)      432.96 (  0.95%)

Negligible differences again. As with tiobench, overall reclaim activity
was comparable.

bonnie++ on ext4
----------------

No interesting performance difference, negligible differences on reclaim
stats.

paralleldd on ext4
------------------

This workload uses varying numbers of dd instances to read large amounts of
data from disk.

                               4.7.0-rc3             4.7.0-rc3
                          mmotm-20160623            nodelru-v9
Amean    Elapsd-1       186.04 (  0.00%)      189.41 ( -1.82%)
Amean    Elapsd-3       192.27 (  0.00%)      191.38 (  0.46%)
Amean    Elapsd-5       185.21 (  0.00%)      182.75 (  1.33%)
Amean    Elapsd-7       183.71 (  0.00%)      182.11 (  0.87%)
Amean    Elapsd-12      180.96 (  0.00%)      181.58 ( -0.35%)
Amean    Elapsd-16      181.36 (  0.00%)      183.72 ( -1.30%)

           4.7.0-rc4   4.7.0-rc4
        mmotm-20160623 nodelru-v9
User         1548.01     1552.44
System       8609.71     8515.08
Elapsed      3587.10     3594.54

There is little or no change in performance but some drop in system CPU usage.

                             4.7.0-rc3   4.7.0-rc3
                        mmotm-20160623  nodelru-v9
Minor Faults                    362662      367360
Major Faults                      1204        1143
Swap Ins                            22           0
Swap Outs                         2855        1029
DMA allocs                           0           0
DMA32 allocs                  31409797    28837521
Normal allocs                 46611853    49231282
Movable allocs                       0           0
Direct pages scanned                 0           0
Kswapd pages scanned          40845270    40869088
Kswapd pages reclaimed        40830976    40855294
Direct pages reclaimed               0           0
Kswapd efficiency                  99%         99%
Kswapd velocity              11386.711   11369.769
Direct efficiency                 100%        100%
Direct velocity                  0.000       0.000
Percentage direct scans             0%          0%
Page writes by reclaim            2855        1029
Page writes file                     0           0
Page writes anon                  2855        1029
Page reclaim immediate             771        1628
Sector Reads                 293312636   293536360
Sector Writes                 18213568    18186480
Page rescued immediate               0           0
Slabs scanned                   128257      132747
Direct inode steals                181          56
Kswapd inode steals                 59        1131

It basically shows that kswapd was active at roughly the same rate in
both kernels. There was also comparable slab scanning activity and direct
reclaim was avoided in both cases. There appears to be a large difference
in numbers of inodes reclaimed but the workload has few active inodes and
is likely a timing artifact.

stutter
-------

stutter simulates a simple workload. One part uses a lot of anonymous
memory, a second measures mmap latency and a third copies a large file.
The primary metric is checking for mmap latency.

stutter
                             4.7.0-rc4             4.7.0-rc4
                        mmotm-20160623            nodelru-v8
Min         mmap     16.6283 (  0.00%)     13.4258 ( 19.26%)
1st-qrtle   mmap     54.7570 (  0.00%)     34.9121 ( 36.24%)
2nd-qrtle   mmap     57.3163 (  0.00%)     46.1147 ( 19.54%)
3rd-qrtle   mmap     58.9976 (  0.00%)     47.1882 ( 20.02%)
Max-90%     mmap     59.7433 (  0.00%)     47.4453 ( 20.58%)
Max-93%     mmap     60.1298 (  0.00%)     47.6037 ( 20.83%)
Max-95%     mmap     73.4112 (  0.00%)     82.8719 (-12.89%)
Max-99%     mmap     92.8542 (  0.00%)     88.8870 (  4.27%)
Max         mmap   1440.6569 (  0.00%)    121.4201 ( 91.57%)
Mean        mmap     59.3493 (  0.00%)     42.2991 ( 28.73%)
Best99%Mean mmap     57.2121 (  0.00%)     41.8207 ( 26.90%)
Best95%Mean mmap     55.9113 (  0.00%)     39.9620 ( 28.53%)
Best90%Mean mmap     55.6199 (  0.00%)     39.3124 ( 29.32%)
Best50%Mean mmap     53.2183 (  0.00%)     33.1307 ( 37.75%)
Best10%Mean mmap     45.9842 (  0.00%)     20.4040 ( 55.63%)
Best5%Mean  mmap     43.2256 (  0.00%)     17.9654 ( 58.44%)
Best1%Mean  mmap     32.9388 (  0.00%)     16.6875 ( 49.34%)

This shows a number of improvements with the worst-case outlier greatly
improved.

Some of the vmstats are interesting

                             4.7.0-rc4   4.7.0-rc4
                          mmotm-20160623nodelru-v8
Swap Ins                           163         502
Swap Outs                            0           0
DMA allocs                           0           0
DMA32 allocs                 618719206  1381662383
Normal allocs                891235743   564138421
Movable allocs                       0           0
Allocation stalls                 2603           1
Direct pages scanned            216787           2
Kswapd pages scanned          50719775    41778378
Kswapd pages reclaimed        41541765    41777639
Direct pages reclaimed          209159           0
Kswapd efficiency                  81%         99%
Kswapd velocity              16859.554   14329.059
Direct efficiency                  96%          0%
Direct velocity                 72.061       0.001
Percentage direct scans             0%          0%
Page writes by reclaim         6215049           0
Page writes file               6215049           0
Page writes anon                     0           0
Page reclaim immediate           70673          90
Sector Reads                  81940800    81680456
Sector Writes                100158984    98816036
Page rescued immediate               0           0
Slabs scanned                  1366954       22683

While this is not guaranteed in all cases, this particular test showed
a large reduction in direct reclaim activity. It's also worth noting
that no page writes were issued from reclaim context.

This series is not without its hazards. There are at least three areas
that I'm concerned with even though I could not reproduce any problems in
that area.

1. Reclaim/compaction is going to be affected because the amount of reclaim is
   no longer targetted at a specific zone. Compaction works on a per-zone basis
   so there is no guarantee that reclaiming a few THP's worth page pages will
   have a positive impact on compaction success rates.

2. The Slab/LRU reclaim ratio is affected because the frequency the shrinkers
   are called is now different. This may or may not be a problem but if it
   is, it'll be because shrinkers are not called enough and some balancing
   is required.

3. The anon/file reclaim ratio may be affected. Pages about to be dirtied are
   distributed between zones and the fair zone allocation policy used to do
   something very similar for anon. The distribution is now different but not
   necessarily in any way that matters but it's still worth bearing in mind.

 Documentation/cgroup-v1/memcg_test.txt        |   4 +-
 Documentation/cgroup-v1/memory.txt            |   4 +-
 arch/s390/appldata/appldata_mem.c             |   2 +-
 arch/tile/mm/pgtable.c                        |  18 +-
 drivers/base/node.c                           |  77 ++-
 drivers/staging/android/lowmemorykiller.c     |  12 +-
 drivers/staging/lustre/lustre/osc/osc_cache.c |   6 +-
 fs/fs-writeback.c                             |   4 +-
 fs/fuse/file.c                                |   8 +-
 fs/nfs/internal.h                             |   2 +-
 fs/nfs/write.c                                |   2 +-
 fs/proc/meminfo.c                             |  20 +-
 include/linux/backing-dev.h                   |   2 +-
 include/linux/memcontrol.h                    |  63 +-
 include/linux/mm.h                            |   5 +
 include/linux/mm_inline.h                     |  39 +-
 include/linux/mm_types.h                      |   2 +-
 include/linux/mmzone.h                        | 161 +++--
 include/linux/swap.h                          |  24 +-
 include/linux/topology.h                      |   2 +-
 include/linux/vm_event_item.h                 |  14 +-
 include/linux/vmstat.h                        | 111 +++-
 include/linux/writeback.h                     |   2 +-
 include/trace/events/vmscan.h                 |  63 +-
 include/trace/events/writeback.h              |  10 +-
 kernel/power/snapshot.c                       |  10 +-
 kernel/sysctl.c                               |   4 +-
 mm/backing-dev.c                              |  15 +-
 mm/compaction.c                               |  48 +-
 mm/filemap.c                                  |  16 +-
 mm/huge_memory.c                              |  12 +-
 mm/internal.h                                 |  11 +-
 mm/khugepaged.c                               |  14 +-
 mm/memcontrol.c                               | 215 +++----
 mm/memory-failure.c                           |   4 +-
 mm/memory_hotplug.c                           |   7 +-
 mm/mempolicy.c                                |   2 +-
 mm/migrate.c                                  |  35 +-
 mm/mlock.c                                    |  12 +-
 mm/page-writeback.c                           | 123 ++--
 mm/page_alloc.c                               | 349 +++++-----
 mm/page_idle.c                                |   4 +-
 mm/rmap.c                                     |  26 +-
 mm/shmem.c                                    |  14 +-
 mm/swap.c                                     |  64 +-
 mm/swap_state.c                               |   4 +-
 mm/util.c                                     |   4 +-
 mm/vmscan.c                                   | 893 +++++++++++++-------------
 mm/vmstat.c                                   | 411 +++++++++---
 mm/workingset.c                               |  54 +-
 50 files changed, 1690 insertions(+), 1318 deletions(-)

-- 
2.6.4

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#1439226 — [PATCH 09/34] mm, vmscan: simplify the logic deciding whether kswapd sleeps

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 09/34] mm, vmscan: simplify the logic deciding whether kswapd sleeps
Message-ID<rSAqm-2Tv-39@gated-at.bofh.it>
In reply to#1439225
kswapd goes through some complex steps trying to figure out if it should
stay awake based on the classzone_idx and the requested order.  It is
unnecessarily complex and passes in an invalid classzone_idx to
balance_pgdat().  What matters most of all is whether a larger order has
been requsted and whether kswapd successfully reclaimed at the previous
order.  This patch irons out the logic to check just that and the end
result is less headache inducing.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/mmzone.h |   5 ++-
 mm/memory_hotplug.c    |   5 ++-
 mm/page_alloc.c        |   2 +-
 mm/vmscan.c            | 101 ++++++++++++++++++++++++-------------------------
 4 files changed, 57 insertions(+), 56 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index edafdaf62e90..4062fa74526f 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -668,8 +668,9 @@ typedef struct pglist_data {
 	wait_queue_head_t pfmemalloc_wait;
 	struct task_struct *kswapd;	/* Protected by
 					   mem_hotplug_begin/end() */
-	int kswapd_max_order;
-	enum zone_type classzone_idx;
+	int kswapd_order;
+	enum zone_type kswapd_classzone_idx;
+
 #ifdef CONFIG_COMPACTION
 	int kcompactd_max_order;
 	enum zone_type kcompactd_classzone_idx;
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index c5278360ca66..065140ecd081 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1209,9 +1209,10 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
 
 		arch_refresh_nodedata(nid, pgdat);
 	} else {
-		/* Reset the nr_zones and classzone_idx to 0 before reuse */
+		/* Reset the nr_zones, order and classzone_idx before reuse */
 		pgdat->nr_zones = 0;
-		pgdat->classzone_idx = 0;
+		pgdat->kswapd_order = 0;
+		pgdat->kswapd_classzone_idx = 0;
 	}
 
 	/* we can use NODE_DATA(nid) from here */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b84b85ae54ff..d25dc24f65f2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6084,7 +6084,7 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
 	unsigned long end_pfn = 0;
 
 	/* pg_data_t should be reset to zero when it's allocated */
-	WARN_ON(pgdat->nr_zones || pgdat->classzone_idx);
+	WARN_ON(pgdat->nr_zones || pgdat->kswapd_classzone_idx);
 
 	reset_deferred_meminit(pgdat);
 	pgdat->node_id = nid;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index a52167eabc96..905c60473126 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2762,7 +2762,7 @@ static bool pfmemalloc_watermark_ok(pg_data_t *pgdat)
 
 	/* kswapd must be awake if processes are being throttled */
 	if (!wmark_ok && waitqueue_active(&pgdat->kswapd_wait)) {
-		pgdat->classzone_idx = min(pgdat->classzone_idx,
+		pgdat->kswapd_classzone_idx = min(pgdat->kswapd_classzone_idx,
 						(enum zone_type)ZONE_NORMAL);
 		wake_up_interruptible(&pgdat->kswapd_wait);
 	}
@@ -3042,11 +3042,11 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining,
 		if (!populated_zone(zone))
 			continue;
 
-		if (zone_balanced(zone, order, classzone_idx))
-			return true;
+		if (!zone_balanced(zone, order, classzone_idx))
+			return false;
 	}
 
-	return false;
+	return true;
 }
 
 /*
@@ -3238,8 +3238,8 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 	return sc.order;
 }
 
-static void kswapd_try_to_sleep(pg_data_t *pgdat, int order,
-				int classzone_idx, int balanced_classzone_idx)
+static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_order,
+				unsigned int classzone_idx)
 {
 	long remaining = 0;
 	DEFINE_WAIT(wait);
@@ -3250,8 +3250,7 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order,
 	prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
 
 	/* Try to sleep for a short interval */
-	if (prepare_kswapd_sleep(pgdat, order, remaining,
-						balanced_classzone_idx)) {
+	if (prepare_kswapd_sleep(pgdat, reclaim_order, remaining, classzone_idx)) {
 		/*
 		 * Compaction records what page blocks it recently failed to
 		 * isolate pages from and skips them in the future scanning.
@@ -3264,9 +3263,20 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order,
 		 * We have freed the memory, now we should compact it to make
 		 * allocation of the requested order possible.
 		 */
-		wakeup_kcompactd(pgdat, order, classzone_idx);
+		wakeup_kcompactd(pgdat, alloc_order, classzone_idx);
 
 		remaining = schedule_timeout(HZ/10);
+
+		/*
+		 * If woken prematurely then reset kswapd_classzone_idx and
+		 * order. The values will either be from a wakeup request or
+		 * the previous request that slept prematurely.
+		 */
+		if (remaining) {
+			pgdat->kswapd_classzone_idx = max(pgdat->kswapd_classzone_idx, classzone_idx);
+			pgdat->kswapd_order = max(pgdat->kswapd_order, reclaim_order);
+		}
+
 		finish_wait(&pgdat->kswapd_wait, &wait);
 		prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
 	}
@@ -3275,8 +3285,7 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order,
 	 * After a short sleep, check if it was a premature sleep. If not, then
 	 * go fully to sleep until explicitly woken up.
 	 */
-	if (prepare_kswapd_sleep(pgdat, order, remaining,
-						balanced_classzone_idx)) {
+	if (prepare_kswapd_sleep(pgdat, reclaim_order, remaining, classzone_idx)) {
 		trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
 
 		/*
@@ -3317,9 +3326,7 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order,
  */
 static int kswapd(void *p)
 {
-	unsigned long order, new_order;
-	int classzone_idx, new_classzone_idx;
-	int balanced_classzone_idx;
+	unsigned int alloc_order, reclaim_order, classzone_idx;
 	pg_data_t *pgdat = (pg_data_t*)p;
 	struct task_struct *tsk = current;
 
@@ -3349,38 +3356,20 @@ static int kswapd(void *p)
 	tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD;
 	set_freezable();
 
-	order = new_order = 0;
-	classzone_idx = new_classzone_idx = pgdat->nr_zones - 1;
-	balanced_classzone_idx = classzone_idx;
+	pgdat->kswapd_order = alloc_order = reclaim_order = 0;
+	pgdat->kswapd_classzone_idx = classzone_idx = 0;
 	for ( ; ; ) {
 		bool ret;
 
-		/*
-		 * While we were reclaiming, there might have been another
-		 * wakeup, so check the values.
-		 */
-		new_order = pgdat->kswapd_max_order;
-		new_classzone_idx = pgdat->classzone_idx;
-		pgdat->kswapd_max_order =  0;
-		pgdat->classzone_idx = pgdat->nr_zones - 1;
+kswapd_try_sleep:
+		kswapd_try_to_sleep(pgdat, alloc_order, reclaim_order,
+					classzone_idx);
 
-		if (order < new_order || classzone_idx > new_classzone_idx) {
-			/*
-			 * Don't sleep if someone wants a larger 'order'
-			 * allocation or has tigher zone constraints
-			 */
-			order = new_order;
-			classzone_idx = new_classzone_idx;
-		} else {
-			kswapd_try_to_sleep(pgdat, order, classzone_idx,
-						balanced_classzone_idx);
-			order = pgdat->kswapd_max_order;
-			classzone_idx = pgdat->classzone_idx;
-			new_order = order;
-			new_classzone_idx = classzone_idx;
-			pgdat->kswapd_max_order = 0;
-			pgdat->classzone_idx = pgdat->nr_zones - 1;
-		}
+		/* Read the new order and classzone_idx */
+		alloc_order = reclaim_order = pgdat->kswapd_order;
+		classzone_idx = pgdat->kswapd_classzone_idx;
+		pgdat->kswapd_order = 0;
+		pgdat->kswapd_classzone_idx = 0;
 
 		ret = try_to_freeze();
 		if (kthread_should_stop())
@@ -3390,12 +3379,24 @@ static int kswapd(void *p)
 		 * We can speed up thawing tasks if we don't call balance_pgdat
 		 * after returning from the refrigerator
 		 */
-		if (!ret) {
-			trace_mm_vmscan_kswapd_wake(pgdat->node_id, order);
+		if (ret)
+			continue;
+
+		/*
+		 * Reclaim begins at the requested order but if a high-order
+		 * reclaim fails then kswapd falls back to reclaiming for
+		 * order-0. If that happens, kswapd will consider sleeping
+		 * for the order it finished reclaiming at (reclaim_order)
+		 * but kcompactd is woken to compact for the original
+		 * request (alloc_order).
+		 */
+		trace_mm_vmscan_kswapd_wake(pgdat->node_id, alloc_order);
+		reclaim_order = balance_pgdat(pgdat, alloc_order, classzone_idx);
+		if (reclaim_order < alloc_order)
+			goto kswapd_try_sleep;
 
-			/* return value ignored until next patch */
-			balance_pgdat(pgdat, order, classzone_idx);
-		}
+		alloc_order = reclaim_order = pgdat->kswapd_order;
+		classzone_idx = pgdat->kswapd_classzone_idx;
 	}
 
 	tsk->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD);
@@ -3418,10 +3419,8 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
 	if (!cpuset_zone_allowed(zone, GFP_KERNEL | __GFP_HARDWALL))
 		return;
 	pgdat = zone->zone_pgdat;
-	if (pgdat->kswapd_max_order < order) {
-		pgdat->kswapd_max_order = order;
-		pgdat->classzone_idx = min(pgdat->classzone_idx, classzone_idx);
-	}
+	pgdat->kswapd_classzone_idx = max(pgdat->kswapd_classzone_idx, classzone_idx);
+	pgdat->kswapd_order = max(pgdat->kswapd_order, order);
 	if (!waitqueue_active(&pgdat->kswapd_wait))
 		return;
 	if (zone_balanced(zone, order, 0))
-- 
2.6.4

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#1439227 — [PATCH 01/34] mm, vmstat: add infrastructure for per-node vmstats

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 01/34] mm, vmstat: add infrastructure for per-node vmstats
Message-ID<rSAqm-2Tv-25@gated-at.bofh.it>
In reply to#1439225
VM statistic counters for reclaim decisions are zone-based.  If the kernel
is to reclaim on a per-node basis then we need to track per-node
statistics but there is no infrastructure for that.  The most notable
change is that the old node_page_state is renamed to
sum_zone_node_page_state.  The new node_page_state takes a pglist_data and
uses per-node stats but none exist yet.  There is some renaming such as
vm_stat to vm_zone_stat and the addition of vm_node_stat and the renaming
of mod_state to mod_zone_state.  Otherwise, this is mostly a mechanical
patch with no functional change.  There is a lot of similarity between the
node and zone helpers which is unfortunate but there was no obvious way of
reusing the code and maintaining type safety.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 drivers/base/node.c    |  76 +++++++------
 include/linux/mm.h     |   5 +
 include/linux/mmzone.h |  13 +++
 include/linux/vmstat.h |  92 +++++++++++++--
 mm/page_alloc.c        |  10 +-
 mm/vmstat.c            | 295 +++++++++++++++++++++++++++++++++++++++++++++----
 mm/workingset.c        |   9 +-
 7 files changed, 424 insertions(+), 76 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index ed0ef0f69489..92d8e090c5b3 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -74,16 +74,16 @@ static ssize_t node_read_meminfo(struct device *dev,
 		       nid, K(i.totalram),
 		       nid, K(i.freeram),
 		       nid, K(i.totalram - i.freeram),
-		       nid, K(node_page_state(nid, NR_ACTIVE_ANON) +
-				node_page_state(nid, NR_ACTIVE_FILE)),
-		       nid, K(node_page_state(nid, NR_INACTIVE_ANON) +
-				node_page_state(nid, NR_INACTIVE_FILE)),
-		       nid, K(node_page_state(nid, NR_ACTIVE_ANON)),
-		       nid, K(node_page_state(nid, NR_INACTIVE_ANON)),
-		       nid, K(node_page_state(nid, NR_ACTIVE_FILE)),
-		       nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
-		       nid, K(node_page_state(nid, NR_UNEVICTABLE)),
-		       nid, K(node_page_state(nid, NR_MLOCK)));
+		       nid, K(sum_zone_node_page_state(nid, NR_ACTIVE_ANON) +
+				sum_zone_node_page_state(nid, NR_ACTIVE_FILE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_INACTIVE_ANON) +
+				sum_zone_node_page_state(nid, NR_INACTIVE_FILE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_ACTIVE_ANON)),
+		       nid, K(sum_zone_node_page_state(nid, NR_INACTIVE_ANON)),
+		       nid, K(sum_zone_node_page_state(nid, NR_ACTIVE_FILE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_INACTIVE_FILE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_UNEVICTABLE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_MLOCK)));
 
 #ifdef CONFIG_HIGHMEM
 	n += sprintf(buf + n,
@@ -117,31 +117,31 @@ static ssize_t node_read_meminfo(struct device *dev,
 		       "Node %d ShmemPmdMapped: %8lu kB\n"
 #endif
 			,
-		       nid, K(node_page_state(nid, NR_FILE_DIRTY)),
-		       nid, K(node_page_state(nid, NR_WRITEBACK)),
-		       nid, K(node_page_state(nid, NR_FILE_PAGES)),
-		       nid, K(node_page_state(nid, NR_FILE_MAPPED)),
-		       nid, K(node_page_state(nid, NR_ANON_PAGES)),
+		       nid, K(sum_zone_node_page_state(nid, NR_FILE_DIRTY)),
+		       nid, K(sum_zone_node_page_state(nid, NR_WRITEBACK)),
+		       nid, K(sum_zone_node_page_state(nid, NR_FILE_PAGES)),
+		       nid, K(sum_zone_node_page_state(nid, NR_FILE_MAPPED)),
+		       nid, K(sum_zone_node_page_state(nid, NR_ANON_PAGES)),
 		       nid, K(i.sharedram),
-		       nid, node_page_state(nid, NR_KERNEL_STACK) *
+		       nid, sum_zone_node_page_state(nid, NR_KERNEL_STACK) *
 				THREAD_SIZE / 1024,
-		       nid, K(node_page_state(nid, NR_PAGETABLE)),
-		       nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
-		       nid, K(node_page_state(nid, NR_BOUNCE)),
-		       nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)),
-		       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
-				node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
-		       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_PAGETABLE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_UNSTABLE_NFS)),
+		       nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_WRITEBACK_TEMP)),
+		       nid, K(sum_zone_node_page_state(nid, NR_SLAB_RECLAIMABLE) +
+				sum_zone_node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_SLAB_RECLAIMABLE)),
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-		       nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
-		       nid, K(node_page_state(nid, NR_ANON_THPS) *
+		       nid, K(sum_zone_node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_ANON_THPS) *
 				       HPAGE_PMD_NR),
-		       nid, K(node_page_state(nid, NR_SHMEM_THPS) *
+		       nid, K(sum_zone_node_page_state(nid, NR_SHMEM_THPS) *
 				       HPAGE_PMD_NR),
-		       nid, K(node_page_state(nid, NR_SHMEM_PMDMAPPED) *
+		       nid, K(sum_zone_node_page_state(nid, NR_SHMEM_PMDMAPPED) *
 				       HPAGE_PMD_NR));
 #else
-		       nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
+		       nid, K(sum_zone_node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
 #endif
 	n += hugetlb_report_node_meminfo(nid, buf + n);
 	return n;
@@ -160,12 +160,12 @@ static ssize_t node_read_numastat(struct device *dev,
 		       "interleave_hit %lu\n"
 		       "local_node %lu\n"
 		       "other_node %lu\n",
-		       node_page_state(dev->id, NUMA_HIT),
-		       node_page_state(dev->id, NUMA_MISS),
-		       node_page_state(dev->id, NUMA_FOREIGN),
-		       node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
-		       node_page_state(dev->id, NUMA_LOCAL),
-		       node_page_state(dev->id, NUMA_OTHER));
+		       sum_zone_node_page_state(dev->id, NUMA_HIT),
+		       sum_zone_node_page_state(dev->id, NUMA_MISS),
+		       sum_zone_node_page_state(dev->id, NUMA_FOREIGN),
+		       sum_zone_node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
+		       sum_zone_node_page_state(dev->id, NUMA_LOCAL),
+		       sum_zone_node_page_state(dev->id, NUMA_OTHER));
 }
 static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
 
@@ -173,12 +173,18 @@ static ssize_t node_read_vmstat(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	int nid = dev->id;
+	struct pglist_data *pgdat = NODE_DATA(nid);
 	int i;
 	int n = 0;
 
 	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 		n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
-			     node_page_state(nid, i));
+			     sum_zone_node_page_state(nid, i));
+
+	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
+		n += sprintf(buf+n, "%s %lu\n",
+			     vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
+			     node_page_state(pgdat, i));
 
 	return n;
 }
diff --git a/include/linux/mm.h b/include/linux/mm.h
index b21e5f30378e..dd79aa2800a3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -933,6 +933,11 @@ static inline struct zone *page_zone(const struct page *page)
 	return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
 }
 
+static inline pg_data_t *page_pgdat(const struct page *page)
+{
+	return NODE_DATA(page_to_nid(page));
+}
+
 #ifdef SECTION_IN_PAGE_FLAGS
 static inline void set_page_section(struct page *page, unsigned long section)
 {
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 19425e988bdc..078ecb81e209 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -160,6 +160,10 @@ enum zone_stat_item {
 	NR_FREE_CMA_PAGES,
 	NR_VM_ZONE_STAT_ITEMS };
 
+enum node_stat_item {
+	NR_VM_NODE_STAT_ITEMS
+};
+
 /*
  * We do arithmetic on the LRU lists in various places in the code,
  * so it is important to keep the active lists LRU_ACTIVE higher in
@@ -267,6 +271,11 @@ struct per_cpu_pageset {
 #endif
 };
 
+struct per_cpu_nodestat {
+	s8 stat_threshold;
+	s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS];
+};
+
 #endif /* !__GENERATING_BOUNDS.H */
 
 enum zone_type {
@@ -695,6 +704,10 @@ typedef struct pglist_data {
 	struct list_head split_queue;
 	unsigned long split_queue_len;
 #endif
+
+	/* Per-node vmstats */
+	struct per_cpu_nodestat __percpu *per_cpu_nodestats;
+	atomic_long_t		vm_stat[NR_VM_NODE_STAT_ITEMS];
 } pg_data_t;
 
 #define node_present_pages(nid)	(NODE_DATA(nid)->node_present_pages)
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index d2da8e053210..d1744aa3ab9c 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -106,20 +106,38 @@ static inline void vm_events_fold_cpu(int cpu)
 		zone_idx(zone), delta)
 
 /*
- * Zone based page accounting with per cpu differentials.
+ * Zone and node-based page accounting with per cpu differentials.
  */
-extern atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
+extern atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS];
+extern atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS];
 
 static inline void zone_page_state_add(long x, struct zone *zone,
 				 enum zone_stat_item item)
 {
 	atomic_long_add(x, &zone->vm_stat[item]);
-	atomic_long_add(x, &vm_stat[item]);
+	atomic_long_add(x, &vm_zone_stat[item]);
+}
+
+static inline void node_page_state_add(long x, struct pglist_data *pgdat,
+				 enum node_stat_item item)
+{
+	atomic_long_add(x, &pgdat->vm_stat[item]);
+	atomic_long_add(x, &vm_node_stat[item]);
 }
 
 static inline unsigned long global_page_state(enum zone_stat_item item)
 {
-	long x = atomic_long_read(&vm_stat[item]);
+	long x = atomic_long_read(&vm_zone_stat[item]);
+#ifdef CONFIG_SMP
+	if (x < 0)
+		x = 0;
+#endif
+	return x;
+}
+
+static inline unsigned long global_node_page_state(enum node_stat_item item)
+{
+	long x = atomic_long_read(&vm_node_stat[item]);
 #ifdef CONFIG_SMP
 	if (x < 0)
 		x = 0;
@@ -161,31 +179,44 @@ static inline unsigned long zone_page_state_snapshot(struct zone *zone,
 }
 
 #ifdef CONFIG_NUMA
-
-extern unsigned long node_page_state(int node, enum zone_stat_item item);
-
+extern unsigned long sum_zone_node_page_state(int node,
+						enum zone_stat_item item);
+extern unsigned long node_page_state(struct pglist_data *pgdat,
+						enum node_stat_item item);
 #else
-
-#define node_page_state(node, item) global_page_state(item)
-
+#define sum_zone_node_page_state(node, item) global_page_state(item)
+#define node_page_state(node, item) global_node_page_state(item)
 #endif /* CONFIG_NUMA */
 
 #define add_zone_page_state(__z, __i, __d) mod_zone_page_state(__z, __i, __d)
 #define sub_zone_page_state(__z, __i, __d) mod_zone_page_state(__z, __i, -(__d))
+#define add_node_page_state(__p, __i, __d) mod_node_page_state(__p, __i, __d)
+#define sub_node_page_state(__p, __i, __d) mod_node_page_state(__p, __i, -(__d))
 
 #ifdef CONFIG_SMP
 void __mod_zone_page_state(struct zone *, enum zone_stat_item item, long);
 void __inc_zone_page_state(struct page *, enum zone_stat_item);
 void __dec_zone_page_state(struct page *, enum zone_stat_item);
 
+void __mod_node_page_state(struct pglist_data *, enum node_stat_item item, long);
+void __inc_node_page_state(struct page *, enum node_stat_item);
+void __dec_node_page_state(struct page *, enum node_stat_item);
+
 void mod_zone_page_state(struct zone *, enum zone_stat_item, long);
 void inc_zone_page_state(struct page *, enum zone_stat_item);
 void dec_zone_page_state(struct page *, enum zone_stat_item);
 
+void mod_node_page_state(struct pglist_data *, enum node_stat_item, long);
+void inc_node_page_state(struct page *, enum node_stat_item);
+void dec_node_page_state(struct page *, enum node_stat_item);
+
 extern void inc_zone_state(struct zone *, enum zone_stat_item);
+extern void inc_node_state(struct pglist_data *, enum node_stat_item);
 extern void __inc_zone_state(struct zone *, enum zone_stat_item);
+extern void __inc_node_state(struct pglist_data *, enum node_stat_item);
 extern void dec_zone_state(struct zone *, enum zone_stat_item);
 extern void __dec_zone_state(struct zone *, enum zone_stat_item);
+extern void __dec_node_state(struct pglist_data *, enum node_stat_item);
 
 void quiet_vmstat(void);
 void cpu_vm_stats_fold(int cpu);
@@ -213,16 +244,34 @@ static inline void __mod_zone_page_state(struct zone *zone,
 	zone_page_state_add(delta, zone, item);
 }
 
+static inline void __mod_node_page_state(struct pglist_data *pgdat,
+			enum node_stat_item item, int delta)
+{
+	node_page_state_add(delta, pgdat, item);
+}
+
 static inline void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 {
 	atomic_long_inc(&zone->vm_stat[item]);
-	atomic_long_inc(&vm_stat[item]);
+	atomic_long_inc(&vm_zone_stat[item]);
+}
+
+static inline void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	atomic_long_inc(&pgdat->vm_stat[item]);
+	atomic_long_inc(&vm_node_stat[item]);
 }
 
 static inline void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 {
 	atomic_long_dec(&zone->vm_stat[item]);
-	atomic_long_dec(&vm_stat[item]);
+	atomic_long_dec(&vm_zone_stat[item]);
+}
+
+static inline void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	atomic_long_dec(&pgdat->vm_stat[item]);
+	atomic_long_dec(&vm_node_stat[item]);
 }
 
 static inline void __inc_zone_page_state(struct page *page,
@@ -231,12 +280,26 @@ static inline void __inc_zone_page_state(struct page *page,
 	__inc_zone_state(page_zone(page), item);
 }
 
+static inline void __inc_node_page_state(struct page *page,
+			enum node_stat_item item)
+{
+	__inc_node_state(page_pgdat(page), item);
+}
+
+
 static inline void __dec_zone_page_state(struct page *page,
 			enum zone_stat_item item)
 {
 	__dec_zone_state(page_zone(page), item);
 }
 
+static inline void __dec_node_page_state(struct page *page,
+			enum node_stat_item item)
+{
+	__dec_node_state(page_pgdat(page), item);
+}
+
+
 /*
  * We only use atomic operations to update counters. So there is no need to
  * disable interrupts.
@@ -245,7 +308,12 @@ static inline void __dec_zone_page_state(struct page *page,
 #define dec_zone_page_state __dec_zone_page_state
 #define mod_zone_page_state __mod_zone_page_state
 
+#define inc_node_page_state __inc_node_page_state
+#define dec_node_page_state __dec_node_page_state
+#define mod_node_page_state __mod_node_page_state
+
 #define inc_zone_state __inc_zone_state
+#define inc_node_state __inc_node_state
 #define dec_zone_state __dec_zone_state
 
 #define set_pgdat_percpu_threshold(pgdat, callback) { }
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 403c5dcd24da..34e46c02a406 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4247,8 +4247,8 @@ void si_meminfo_node(struct sysinfo *val, int nid)
 	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
 		managed_pages += pgdat->node_zones[zone_type].managed_pages;
 	val->totalram = managed_pages;
-	val->sharedram = node_page_state(nid, NR_SHMEM);
-	val->freeram = node_page_state(nid, NR_FREE_PAGES);
+	val->sharedram = sum_zone_node_page_state(nid, NR_SHMEM);
+	val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
 #ifdef CONFIG_HIGHMEM
 	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
 		struct zone *zone = &pgdat->node_zones[zone_type];
@@ -5373,6 +5373,11 @@ static void __meminit setup_zone_pageset(struct zone *zone)
 	zone->pageset = alloc_percpu(struct per_cpu_pageset);
 	for_each_possible_cpu(cpu)
 		zone_pageset_init(zone, cpu);
+
+	if (!zone->zone_pgdat->per_cpu_nodestats) {
+		zone->zone_pgdat->per_cpu_nodestats =
+			alloc_percpu(struct per_cpu_nodestat);
+	}
 }
 
 /*
@@ -6078,6 +6083,7 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
 	reset_deferred_meminit(pgdat);
 	pgdat->node_id = nid;
 	pgdat->node_start_pfn = node_start_pfn;
+	pgdat->per_cpu_nodestats = NULL;
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
 	pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 7997f52935c9..3345d396a99b 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -86,8 +86,10 @@ void vm_events_fold_cpu(int cpu)
  *
  * vm_stat contains the global counters
  */
-atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
-EXPORT_SYMBOL(vm_stat);
+atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
+atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
+EXPORT_SYMBOL(vm_zone_stat);
+EXPORT_SYMBOL(vm_node_stat);
 
 #ifdef CONFIG_SMP
 
@@ -167,19 +169,36 @@ int calculate_normal_threshold(struct zone *zone)
  */
 void refresh_zone_stat_thresholds(void)
 {
+	struct pglist_data *pgdat;
 	struct zone *zone;
 	int cpu;
 	int threshold;
 
+	/* Zero current pgdat thresholds */
+	for_each_online_pgdat(pgdat) {
+		for_each_online_cpu(cpu) {
+			per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
+		}
+	}
+
 	for_each_populated_zone(zone) {
+		struct pglist_data *pgdat = zone->zone_pgdat;
 		unsigned long max_drift, tolerate_drift;
 
 		threshold = calculate_normal_threshold(zone);
 
-		for_each_online_cpu(cpu)
+		for_each_online_cpu(cpu) {
+			int pgdat_threshold;
+
 			per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 							= threshold;
 
+			/* Base nodestat threshold on the largest populated zone. */
+			pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
+			per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
+				= max(threshold, pgdat_threshold);
+		}
+
 		/*
 		 * Only set percpu_drift_mark if there is a danger that
 		 * NR_FREE_PAGES reports the low watermark is ok when in fact
@@ -238,6 +257,26 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 }
 EXPORT_SYMBOL(__mod_zone_page_state);
 
+void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
+				long delta)
+{
+	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
+	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	long x;
+	long t;
+
+	x = delta + __this_cpu_read(*p);
+
+	t = __this_cpu_read(pcp->stat_threshold);
+
+	if (unlikely(x > t || x < -t)) {
+		node_page_state_add(x, pgdat, item);
+		x = 0;
+	}
+	__this_cpu_write(*p, x);
+}
+EXPORT_SYMBOL(__mod_node_page_state);
+
 /*
  * Optimized increment and decrement functions.
  *
@@ -277,12 +316,34 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 	}
 }
 
+void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
+	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	s8 v, t;
+
+	v = __this_cpu_inc_return(*p);
+	t = __this_cpu_read(pcp->stat_threshold);
+	if (unlikely(v > t)) {
+		s8 overstep = t >> 1;
+
+		node_page_state_add(v + overstep, pgdat, item);
+		__this_cpu_write(*p, -overstep);
+	}
+}
+
 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 {
 	__inc_zone_state(page_zone(page), item);
 }
 EXPORT_SYMBOL(__inc_zone_page_state);
 
+void __inc_node_page_state(struct page *page, enum node_stat_item item)
+{
+	__inc_node_state(page_pgdat(page), item);
+}
+EXPORT_SYMBOL(__inc_node_page_state);
+
 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 {
 	struct per_cpu_pageset __percpu *pcp = zone->pageset;
@@ -299,12 +360,34 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 	}
 }
 
+void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
+	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	s8 v, t;
+
+	v = __this_cpu_dec_return(*p);
+	t = __this_cpu_read(pcp->stat_threshold);
+	if (unlikely(v < - t)) {
+		s8 overstep = t >> 1;
+
+		node_page_state_add(v - overstep, pgdat, item);
+		__this_cpu_write(*p, overstep);
+	}
+}
+
 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 {
 	__dec_zone_state(page_zone(page), item);
 }
 EXPORT_SYMBOL(__dec_zone_page_state);
 
+void __dec_node_page_state(struct page *page, enum node_stat_item item)
+{
+	__dec_node_state(page_pgdat(page), item);
+}
+EXPORT_SYMBOL(__dec_node_page_state);
+
 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL
 /*
  * If we have cmpxchg_local support then we do not need to incur the overhead
@@ -318,8 +401,8 @@ EXPORT_SYMBOL(__dec_zone_page_state);
  *     1       Overstepping half of threshold
  *     -1      Overstepping minus half of threshold
 */
-static inline void mod_state(struct zone *zone, enum zone_stat_item item,
-			     long delta, int overstep_mode)
+static inline void mod_zone_state(struct zone *zone,
+       enum zone_stat_item item, long delta, int overstep_mode)
 {
 	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 	s8 __percpu *p = pcp->vm_stat_diff + item;
@@ -359,26 +442,88 @@ static inline void mod_state(struct zone *zone, enum zone_stat_item item,
 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 			 long delta)
 {
-	mod_state(zone, item, delta, 0);
+	mod_zone_state(zone, item, delta, 0);
 }
 EXPORT_SYMBOL(mod_zone_page_state);
 
 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 {
-	mod_state(zone, item, 1, 1);
+	mod_zone_state(zone, item, 1, 1);
 }
 
 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 {
-	mod_state(page_zone(page), item, 1, 1);
+	mod_zone_state(page_zone(page), item, 1, 1);
 }
 EXPORT_SYMBOL(inc_zone_page_state);
 
 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 {
-	mod_state(page_zone(page), item, -1, -1);
+	mod_zone_state(page_zone(page), item, -1, -1);
 }
 EXPORT_SYMBOL(dec_zone_page_state);
+
+static inline void mod_node_state(struct pglist_data *pgdat,
+       enum node_stat_item item, int delta, int overstep_mode)
+{
+	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
+	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	long o, n, t, z;
+
+	do {
+		z = 0;  /* overflow to node counters */
+
+		/*
+		 * The fetching of the stat_threshold is racy. We may apply
+		 * a counter threshold to the wrong the cpu if we get
+		 * rescheduled while executing here. However, the next
+		 * counter update will apply the threshold again and
+		 * therefore bring the counter under the threshold again.
+		 *
+		 * Most of the time the thresholds are the same anyways
+		 * for all cpus in a node.
+		 */
+		t = this_cpu_read(pcp->stat_threshold);
+
+		o = this_cpu_read(*p);
+		n = delta + o;
+
+		if (n > t || n < -t) {
+			int os = overstep_mode * (t >> 1) ;
+
+			/* Overflow must be added to node counters */
+			z = n + os;
+			n = -os;
+		}
+	} while (this_cpu_cmpxchg(*p, o, n) != o);
+
+	if (z)
+		node_page_state_add(z, pgdat, item);
+}
+
+void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
+					long delta)
+{
+	mod_node_state(pgdat, item, delta, 0);
+}
+EXPORT_SYMBOL(mod_node_page_state);
+
+void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	mod_node_state(pgdat, item, 1, 1);
+}
+
+void inc_node_page_state(struct page *page, enum node_stat_item item)
+{
+	mod_node_state(page_pgdat(page), item, 1, 1);
+}
+EXPORT_SYMBOL(inc_node_page_state);
+
+void dec_node_page_state(struct page *page, enum node_stat_item item)
+{
+	mod_node_state(page_pgdat(page), item, -1, -1);
+}
+EXPORT_SYMBOL(dec_node_page_state);
 #else
 /*
  * Use interrupt disable to serialize counter updates
@@ -424,21 +569,69 @@ void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 	local_irq_restore(flags);
 }
 EXPORT_SYMBOL(dec_zone_page_state);
-#endif
 
+void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__inc_node_state(pgdat, item);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(inc_node_state);
+
+void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
+					long delta)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__mod_node_page_state(pgdat, item, delta);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(mod_node_page_state);
+
+void inc_node_page_state(struct page *page, enum node_stat_item item)
+{
+	unsigned long flags;
+	struct pglist_data *pgdat;
+
+	pgdat = page_pgdat(page);
+	local_irq_save(flags);
+	__inc_node_state(pgdat, item);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(inc_node_page_state);
+
+void dec_node_page_state(struct page *page, enum node_stat_item item)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__dec_node_page_state(page, item);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(dec_node_page_state);
+#endif
 
 /*
  * Fold a differential into the global counters.
  * Returns the number of counters updated.
  */
-static int fold_diff(int *diff)
+static int fold_diff(int *zone_diff, int *node_diff)
 {
 	int i;
 	int changes = 0;
 
 	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
-		if (diff[i]) {
-			atomic_long_add(diff[i], &vm_stat[i]);
+		if (zone_diff[i]) {
+			atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
+			changes++;
+	}
+
+	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
+		if (node_diff[i]) {
+			atomic_long_add(node_diff[i], &vm_node_stat[i]);
 			changes++;
 	}
 	return changes;
@@ -462,9 +655,11 @@ static int fold_diff(int *diff)
  */
 static int refresh_cpu_vm_stats(bool do_pagesets)
 {
+	struct pglist_data *pgdat;
 	struct zone *zone;
 	int i;
-	int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
+	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
+	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 	int changes = 0;
 
 	for_each_populated_zone(zone) {
@@ -477,7 +672,7 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
 			if (v) {
 
 				atomic_long_add(v, &zone->vm_stat[i]);
-				global_diff[i] += v;
+				global_zone_diff[i] += v;
 #ifdef CONFIG_NUMA
 				/* 3 seconds idle till flush */
 				__this_cpu_write(p->expire, 3);
@@ -516,7 +711,22 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
 		}
 #endif
 	}
-	changes += fold_diff(global_diff);
+
+	for_each_online_pgdat(pgdat) {
+		struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
+
+		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
+			int v;
+
+			v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
+			if (v) {
+				atomic_long_add(v, &pgdat->vm_stat[i]);
+				global_node_diff[i] += v;
+			}
+		}
+	}
+
+	changes += fold_diff(global_zone_diff, global_node_diff);
 	return changes;
 }
 
@@ -527,9 +737,11 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
  */
 void cpu_vm_stats_fold(int cpu)
 {
+	struct pglist_data *pgdat;
 	struct zone *zone;
 	int i;
-	int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
+	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
+	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 
 	for_each_populated_zone(zone) {
 		struct per_cpu_pageset *p;
@@ -543,11 +755,27 @@ void cpu_vm_stats_fold(int cpu)
 				v = p->vm_stat_diff[i];
 				p->vm_stat_diff[i] = 0;
 				atomic_long_add(v, &zone->vm_stat[i]);
-				global_diff[i] += v;
+				global_zone_diff[i] += v;
 			}
 	}
 
-	fold_diff(global_diff);
+	for_each_online_pgdat(pgdat) {
+		struct per_cpu_nodestat *p;
+
+		p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
+
+		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
+			if (p->vm_node_stat_diff[i]) {
+				int v;
+
+				v = p->vm_node_stat_diff[i];
+				p->vm_node_stat_diff[i] = 0;
+				atomic_long_add(v, &pgdat->vm_stat[i]);
+				global_node_diff[i] += v;
+			}
+	}
+
+	fold_diff(global_zone_diff, global_node_diff);
 }
 
 /*
@@ -563,16 +791,19 @@ void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
 			int v = pset->vm_stat_diff[i];
 			pset->vm_stat_diff[i] = 0;
 			atomic_long_add(v, &zone->vm_stat[i]);
-			atomic_long_add(v, &vm_stat[i]);
+			atomic_long_add(v, &vm_zone_stat[i]);
 		}
 }
 #endif
 
 #ifdef CONFIG_NUMA
 /*
- * Determine the per node value of a stat item.
+ * Determine the per node value of a stat item. This function
+ * is called frequently in a NUMA machine, so try to be as
+ * frugal as possible.
  */
-unsigned long node_page_state(int node, enum zone_stat_item item)
+unsigned long sum_zone_node_page_state(int node,
+				 enum zone_stat_item item)
 {
 	struct zone *zones = NODE_DATA(node)->node_zones;
 	int i;
@@ -584,6 +815,19 @@ unsigned long node_page_state(int node, enum zone_stat_item item)
 	return count;
 }
 
+/*
+ * Determine the per node value of a stat item.
+ */
+unsigned long node_page_state(struct pglist_data *pgdat,
+				enum node_stat_item item)
+{
+	long x = atomic_long_read(&pgdat->vm_stat[item]);
+#ifdef CONFIG_SMP
+	if (x < 0)
+		x = 0;
+#endif
+	return x;
+}
 #endif
 
 #ifdef CONFIG_COMPACTION
@@ -1287,6 +1531,7 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
 	if (*pos >= ARRAY_SIZE(vmstat_text))
 		return NULL;
 	stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
+			  NR_VM_NODE_STAT_ITEMS * sizeof(unsigned long) +
 			  NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
 
 #ifdef CONFIG_VM_EVENT_COUNTERS
@@ -1301,6 +1546,10 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
 		v[i] = global_page_state(i);
 	v += NR_VM_ZONE_STAT_ITEMS;
 
+	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
+		v[i] = global_node_page_state(i);
+	v += NR_VM_NODE_STAT_ITEMS;
+
 	global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
 			    v + NR_DIRTY_THRESHOLD);
 	v += NR_VM_WRITEBACK_STAT_ITEMS;
@@ -1390,7 +1639,7 @@ int vmstat_refresh(struct ctl_table *table, int write,
 	if (err)
 		return err;
 	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
-		val = atomic_long_read(&vm_stat[i]);
+		val = atomic_long_read(&vm_zone_stat[i]);
 		if (val < 0) {
 			switch (i) {
 			case NR_ALLOC_BATCH:
diff --git a/mm/workingset.c b/mm/workingset.c
index 8252de4566e9..ba972ac2dfdd 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -351,12 +351,13 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
 	shadow_nodes = list_lru_shrink_count(&workingset_shadow_nodes, sc);
 	local_irq_enable();
 
-	if (memcg_kmem_enabled())
+	if (memcg_kmem_enabled()) {
 		pages = mem_cgroup_node_nr_lru_pages(sc->memcg, sc->nid,
 						     LRU_ALL_FILE);
-	else
-		pages = node_page_state(sc->nid, NR_ACTIVE_FILE) +
-			node_page_state(sc->nid, NR_INACTIVE_FILE);
+	} else {
+		pages = sum_zone_node_page_state(sc->nid, NR_ACTIVE_FILE) +
+			sum_zone_node_page_state(sc->nid, NR_INACTIVE_FILE);
+	}
 
 	/*
 	 * Active cache pages are limited to 50% of memory, and shadow
-- 
2.6.4

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#1439228 — [PATCH 13/34] mm, vmscan: make shrink_node decisions more node-centric

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 13/34] mm, vmscan: make shrink_node decisions more node-centric
Message-ID<rSAqm-2Tv-21@gated-at.bofh.it>
In reply to#1439225
Earlier patches focused on having direct reclaim and kswapd use data that
is node-centric for reclaiming but shrink_node() itself still uses too
much zone information.  This patch removes unnecessary zone-based
information with the most important decision being whether to continue
reclaim or not.  Some memcg APIs are adjusted as a result even though
memcg itself still uses some zone information.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/memcontrol.h | 19 ++++++++-------
 include/linux/mmzone.h     |  4 ++--
 include/linux/swap.h       |  2 +-
 mm/memcontrol.c            |  4 ++--
 mm/page_alloc.c            |  2 +-
 mm/vmscan.c                | 59 ++++++++++++++++++++++++++--------------------
 mm/workingset.c            |  6 ++---
 7 files changed, 52 insertions(+), 44 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 68f1121c8fe7..c13227d018f2 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -325,22 +325,23 @@ mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone)
 }
 
 /**
- * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
+ * mem_cgroup_lruvec - get the lru list vector for a node or a memcg zone
+ * @node: node of the wanted lruvec
  * @zone: zone of the wanted lruvec
  * @memcg: memcg of the wanted lruvec
  *
- * Returns the lru list vector holding pages for the given @zone and
- * @mem.  This can be the global zone lruvec, if the memory controller
+ * Returns the lru list vector holding pages for a given @node or a given
+ * @memcg and @zone. This can be the node lruvec, if the memory controller
  * is disabled.
  */
-static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
-						    struct mem_cgroup *memcg)
+static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
+				struct zone *zone, struct mem_cgroup *memcg)
 {
 	struct mem_cgroup_per_zone *mz;
 	struct lruvec *lruvec;
 
 	if (mem_cgroup_disabled()) {
-		lruvec = zone_lruvec(zone);
+		lruvec = node_lruvec(pgdat);
 		goto out;
 	}
 
@@ -610,10 +611,10 @@ static inline void mem_cgroup_migrate(struct page *old, struct page *new)
 {
 }
 
-static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
-						    struct mem_cgroup *memcg)
+static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
+				struct zone *zone, struct mem_cgroup *memcg)
 {
-	return zone_lruvec(zone);
+	return node_lruvec(pgdat);
 }
 
 static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 4062fa74526f..895c365e3259 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -739,9 +739,9 @@ static inline spinlock_t *zone_lru_lock(struct zone *zone)
 	return &zone->zone_pgdat->lru_lock;
 }
 
-static inline struct lruvec *zone_lruvec(struct zone *zone)
+static inline struct lruvec *node_lruvec(struct pglist_data *pgdat)
 {
-	return &zone->zone_pgdat->lruvec;
+	return &pgdat->lruvec;
 }
 
 static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 916e2eddecd6..0ad616d7c381 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -316,7 +316,7 @@ extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 						  unsigned long nr_pages,
 						  gfp_t gfp_mask,
 						  bool may_swap);
-extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
+extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
 						gfp_t gfp_mask, bool noswap,
 						struct zone *zone,
 						unsigned long *nr_scanned);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 50c86ad121bc..c9ebec98e92a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1432,8 +1432,8 @@ static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
 			}
 			continue;
 		}
-		total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
-						     zone, &nr_scanned);
+		total += mem_cgroup_shrink_node(victim, gfp_mask, false,
+					zone, &nr_scanned);
 		*total_scanned += nr_scanned;
 		if (!soft_limit_excess(root_memcg))
 			break;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d25dc24f65f2..8215c51d5b23 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5954,6 +5954,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
 #endif
 	pgdat_page_ext_init(pgdat);
 	spin_lock_init(&pgdat->lru_lock);
+	lruvec_init(node_lruvec(pgdat));
 
 	for (j = 0; j < MAX_NR_ZONES; j++) {
 		struct zone *zone = pgdat->node_zones + j;
@@ -6016,7 +6017,6 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
 		/* For bootup, initialized properly in watermark setup */
 		mod_zone_page_state(zone, NR_ALLOC_BATCH, zone->managed_pages);
 
-		lruvec_init(zone_lruvec(zone));
 		if (!size)
 			continue;
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b7a276f4b1b0..f0bea68b8780 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2224,12 +2224,13 @@ static inline void init_tlb_ubc(void)
 #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
 
 /*
- * This is a basic per-zone page freer.  Used by both kswapd and direct reclaim.
+ * This is a basic per-node page freer.  Used by both kswapd and direct reclaim.
  */
-static void shrink_zone_memcg(struct zone *zone, struct mem_cgroup *memcg,
+static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memcg,
 			      struct scan_control *sc, unsigned long *lru_pages)
 {
-	struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+	struct zone *zone = &pgdat->node_zones[sc->reclaim_idx];
+	struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, zone, memcg);
 	unsigned long nr[NR_LRU_LISTS];
 	unsigned long targets[NR_LRU_LISTS];
 	unsigned long nr_to_scan;
@@ -2362,13 +2363,14 @@ static bool in_reclaim_compaction(struct scan_control *sc)
  * calls try_to_compact_zone() that it will have enough free pages to succeed.
  * It will give up earlier than that if there is difficulty reclaiming pages.
  */
-static inline bool should_continue_reclaim(struct zone *zone,
+static inline bool should_continue_reclaim(struct pglist_data *pgdat,
 					unsigned long nr_reclaimed,
 					unsigned long nr_scanned,
 					struct scan_control *sc)
 {
 	unsigned long pages_for_compaction;
 	unsigned long inactive_lru_pages;
+	int z;
 
 	/* If not in reclaim/compaction mode, stop */
 	if (!in_reclaim_compaction(sc))
@@ -2402,21 +2404,27 @@ static inline bool should_continue_reclaim(struct zone *zone,
 	 * inactive lists are large enough, continue reclaiming
 	 */
 	pages_for_compaction = (2UL << sc->order);
-	inactive_lru_pages = node_page_state(zone->zone_pgdat, NR_INACTIVE_FILE);
+	inactive_lru_pages = node_page_state(pgdat, NR_INACTIVE_FILE);
 	if (get_nr_swap_pages() > 0)
-		inactive_lru_pages += node_page_state(zone->zone_pgdat, NR_INACTIVE_ANON);
+		inactive_lru_pages += node_page_state(pgdat, NR_INACTIVE_ANON);
 	if (sc->nr_reclaimed < pages_for_compaction &&
 			inactive_lru_pages > pages_for_compaction)
 		return true;
 
 	/* If compaction would go ahead or the allocation would succeed, stop */
-	switch (compaction_suitable(zone, sc->order, 0, 0)) {
-	case COMPACT_PARTIAL:
-	case COMPACT_CONTINUE:
-		return false;
-	default:
-		return true;
+	for (z = 0; z <= sc->reclaim_idx; z++) {
+		struct zone *zone = &pgdat->node_zones[z];
+
+		switch (compaction_suitable(zone, sc->order, 0, sc->reclaim_idx)) {
+		case COMPACT_PARTIAL:
+		case COMPACT_CONTINUE:
+			return false;
+		default:
+			/* check next zone */
+			;
+		}
 	}
+	return true;
 }
 
 static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
@@ -2425,15 +2433,14 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
 	struct reclaim_state *reclaim_state = current->reclaim_state;
 	unsigned long nr_reclaimed, nr_scanned;
 	bool reclaimable = false;
-	struct zone *zone = &pgdat->node_zones[classzone_idx];
 
 	do {
 		struct mem_cgroup *root = sc->target_mem_cgroup;
 		struct mem_cgroup_reclaim_cookie reclaim = {
-			.zone = zone,
+			.zone = &pgdat->node_zones[classzone_idx],
 			.priority = sc->priority,
 		};
-		unsigned long zone_lru_pages = 0;
+		unsigned long node_lru_pages = 0;
 		struct mem_cgroup *memcg;
 
 		nr_reclaimed = sc->nr_reclaimed;
@@ -2454,11 +2461,11 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
 			reclaimed = sc->nr_reclaimed;
 			scanned = sc->nr_scanned;
 
-			shrink_zone_memcg(zone, memcg, sc, &lru_pages);
-			zone_lru_pages += lru_pages;
+			shrink_node_memcg(pgdat, memcg, sc, &lru_pages);
+			node_lru_pages += lru_pages;
 
 			if (!global_reclaim(sc))
-				shrink_slab(sc->gfp_mask, zone_to_nid(zone),
+				shrink_slab(sc->gfp_mask, pgdat->node_id,
 					    memcg, sc->nr_scanned - scanned,
 					    lru_pages);
 
@@ -2470,7 +2477,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
 			/*
 			 * Direct reclaim and kswapd have to scan all memory
 			 * cgroups to fulfill the overall scan target for the
-			 * zone.
+			 * node.
 			 *
 			 * Limit reclaim, on the other hand, only cares about
 			 * nr_to_reclaim pages to be reclaimed and it will
@@ -2489,9 +2496,9 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
 		 * the eligible LRU pages were scanned.
 		 */
 		if (global_reclaim(sc))
-			shrink_slab(sc->gfp_mask, zone_to_nid(zone), NULL,
+			shrink_slab(sc->gfp_mask, pgdat->node_id, NULL,
 				    sc->nr_scanned - nr_scanned,
-				    zone_lru_pages);
+				    node_lru_pages);
 
 		if (reclaim_state) {
 			sc->nr_reclaimed += reclaim_state->reclaimed_slab;
@@ -2506,7 +2513,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
 		if (sc->nr_reclaimed - nr_reclaimed)
 			reclaimable = true;
 
-	} while (should_continue_reclaim(zone, sc->nr_reclaimed - nr_reclaimed,
+	} while (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed,
 					 sc->nr_scanned - nr_scanned, sc));
 
 	return reclaimable;
@@ -2906,7 +2913,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 
 #ifdef CONFIG_MEMCG
 
-unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
+unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
 						gfp_t gfp_mask, bool noswap,
 						struct zone *zone,
 						unsigned long *nr_scanned)
@@ -2931,11 +2938,11 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
 	/*
 	 * NOTE: Although we can get the priority field, using it
 	 * here is not a good idea, since it limits the pages we can scan.
-	 * if we don't reclaim here, the shrink_zone from balance_pgdat
+	 * if we don't reclaim here, the shrink_node from balance_pgdat
 	 * will pick up pages from other mem cgroup's as well. We hack
 	 * the priority and make it zero.
 	 */
-	shrink_zone_memcg(zone, memcg, &sc, &lru_pages);
+	shrink_node_memcg(zone->zone_pgdat, memcg, &sc, &lru_pages);
 
 	trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);
 
@@ -2994,7 +3001,7 @@ static void age_active_anon(struct pglist_data *pgdat,
 
 	memcg = mem_cgroup_iter(NULL, NULL, NULL);
 	do {
-		struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+		struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, zone, memcg);
 
 		if (inactive_list_is_low(lruvec, false))
 			shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
diff --git a/mm/workingset.c b/mm/workingset.c
index ebe14445809a..de68ad681585 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -218,7 +218,7 @@ void *workingset_eviction(struct address_space *mapping, struct page *page)
 	VM_BUG_ON_PAGE(page_count(page), page);
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 
-	lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+	lruvec = mem_cgroup_lruvec(zone->zone_pgdat, zone, memcg);
 	eviction = atomic_long_inc_return(&lruvec->inactive_age);
 	return pack_shadow(memcgid, zone, eviction);
 }
@@ -267,7 +267,7 @@ bool workingset_refault(void *shadow)
 		rcu_read_unlock();
 		return false;
 	}
-	lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+	lruvec = mem_cgroup_lruvec(zone->zone_pgdat, zone, memcg);
 	refault = atomic_long_read(&lruvec->inactive_age);
 	active_file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE);
 	rcu_read_unlock();
@@ -319,7 +319,7 @@ void workingset_activation(struct page *page)
 	memcg = page_memcg_rcu(page);
 	if (!mem_cgroup_disabled() && !memcg)
 		goto out;
-	lruvec = mem_cgroup_zone_lruvec(page_zone(page), memcg);
+	lruvec = mem_cgroup_lruvec(page_pgdat(page), page_zone(page), memcg);
 	atomic_long_inc(&lruvec->inactive_age);
 out:
 	rcu_read_unlock();
-- 
2.6.4

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#1439229 — [PATCH 16/34] mm, page_alloc: consider dirtyable memory in terms of nodes

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 16/34] mm, page_alloc: consider dirtyable memory in terms of nodes
Message-ID<rSAqm-2Tv-27@gated-at.bofh.it>
In reply to#1439225
Historically dirty pages were spread among zones but now that LRUs are
per-node it is more appropriate to consider dirty pages in a node.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
---
 include/linux/mmzone.h    | 12 +++----
 include/linux/writeback.h |  2 +-
 mm/page-writeback.c       | 91 +++++++++++++++++++++++++++++++----------------
 mm/page_alloc.c           | 26 ++++++--------
 4 files changed, 79 insertions(+), 52 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 62f477d6cfe8..fae2fe3c6942 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -363,12 +363,6 @@ struct zone {
 	struct pglist_data	*zone_pgdat;
 	struct per_cpu_pageset __percpu *pageset;
 
-	/*
-	 * This is a per-zone reserve of pages that are not available
-	 * to userspace allocations.
-	 */
-	unsigned long		totalreserve_pages;
-
 #ifndef CONFIG_SPARSEMEM
 	/*
 	 * Flags for a pageblock_nr_pages block. See pageblock-flags.h.
@@ -687,6 +681,12 @@ typedef struct pglist_data {
 	/* Number of pages migrated during the rate limiting time interval */
 	unsigned long numabalancing_migrate_nr_pages;
 #endif
+	/*
+	 * This is a per-node reserve of pages that are not available
+	 * to userspace allocations.
+	 */
+	unsigned long		totalreserve_pages;
+
 	/* Write-intensive fields used by page reclaim */
 	ZONE_PADDING(_pad1_)
 	spinlock_t		lru_lock;
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 717e6149e753..fc1e16c25a29 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -320,7 +320,7 @@ void laptop_mode_timer_fn(unsigned long data);
 static inline void laptop_sync_completion(void) { }
 #endif
 void throttle_vm_writeout(gfp_t gfp_mask);
-bool zone_dirty_ok(struct zone *zone);
+bool node_dirty_ok(struct pglist_data *pgdat);
 int wb_domain_init(struct wb_domain *dom, gfp_t gfp);
 #ifdef CONFIG_CGROUP_WRITEBACK
 void wb_domain_exit(struct wb_domain *dom);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0ada2b2954b0..f7c0fb993fb9 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -267,26 +267,35 @@ static void wb_min_max_ratio(struct bdi_writeback *wb,
  */
 
 /**
- * zone_dirtyable_memory - number of dirtyable pages in a zone
- * @zone: the zone
+ * node_dirtyable_memory - number of dirtyable pages in a node
+ * @pgdat: the node
  *
- * Returns the zone's number of pages potentially available for dirty
- * page cache.  This is the base value for the per-zone dirty limits.
+ * Returns the node's number of pages potentially available for dirty
+ * page cache.  This is the base value for the per-node dirty limits.
  */
-static unsigned long zone_dirtyable_memory(struct zone *zone)
+static unsigned long node_dirtyable_memory(struct pglist_data *pgdat)
 {
-	unsigned long nr_pages;
+	unsigned long nr_pages = 0;
+	int z;
+
+	for (z = 0; z < MAX_NR_ZONES; z++) {
+		struct zone *zone = pgdat->node_zones + z;
+
+		if (!populated_zone(zone))
+			continue;
+
+		nr_pages += zone_page_state(zone, NR_FREE_PAGES);
+	}
 
-	nr_pages = zone_page_state(zone, NR_FREE_PAGES);
 	/*
 	 * Pages reserved for the kernel should not be considered
 	 * dirtyable, to prevent a situation where reclaim has to
 	 * clean pages in order to balance the zones.
 	 */
-	nr_pages -= min(nr_pages, zone->totalreserve_pages);
+	nr_pages -= min(nr_pages, pgdat->totalreserve_pages);
 
-	nr_pages += node_page_state(zone->zone_pgdat, NR_INACTIVE_FILE);
-	nr_pages += node_page_state(zone->zone_pgdat, NR_ACTIVE_FILE);
+	nr_pages += node_page_state(pgdat, NR_INACTIVE_FILE);
+	nr_pages += node_page_state(pgdat, NR_ACTIVE_FILE);
 
 	return nr_pages;
 }
@@ -299,13 +308,24 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
 	int i;
 
 	for_each_node_state(node, N_HIGH_MEMORY) {
-		for (i = 0; i < MAX_NR_ZONES; i++) {
-			struct zone *z = &NODE_DATA(node)->node_zones[i];
+		for (i = ZONE_NORMAL + 1; i < MAX_NR_ZONES; i++) {
+			struct zone *z;
+			unsigned long dirtyable;
+
+			if (!is_highmem_idx(i))
+				continue;
+
+			z = &NODE_DATA(node)->node_zones[i];
+			dirtyable = zone_page_state(z, NR_FREE_PAGES) +
+				zone_page_state(z, NR_ZONE_LRU_FILE);
 
-			if (is_highmem(z))
-				x += zone_dirtyable_memory(z);
+			/* watch for underflows */
+			dirtyable -= min(dirtyable, high_wmark_pages(z));
+
+			x += dirtyable;
 		}
 	}
+
 	/*
 	 * Unreclaimable memory (kernel memory or anonymous memory
 	 * without swap) can bring down the dirtyable pages below
@@ -445,23 +465,23 @@ void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty)
 }
 
 /**
- * zone_dirty_limit - maximum number of dirty pages allowed in a zone
- * @zone: the zone
+ * node_dirty_limit - maximum number of dirty pages allowed in a node
+ * @pgdat: the node
  *
- * Returns the maximum number of dirty pages allowed in a zone, based
- * on the zone's dirtyable memory.
+ * Returns the maximum number of dirty pages allowed in a node, based
+ * on the node's dirtyable memory.
  */
-static unsigned long zone_dirty_limit(struct zone *zone)
+static unsigned long node_dirty_limit(struct pglist_data *pgdat)
 {
-	unsigned long zone_memory = zone_dirtyable_memory(zone);
+	unsigned long node_memory = node_dirtyable_memory(pgdat);
 	struct task_struct *tsk = current;
 	unsigned long dirty;
 
 	if (vm_dirty_bytes)
 		dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE) *
-			zone_memory / global_dirtyable_memory();
+			node_memory / global_dirtyable_memory();
 	else
-		dirty = vm_dirty_ratio * zone_memory / 100;
+		dirty = vm_dirty_ratio * node_memory / 100;
 
 	if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk))
 		dirty += dirty / 4;
@@ -470,19 +490,30 @@ static unsigned long zone_dirty_limit(struct zone *zone)
 }
 
 /**
- * zone_dirty_ok - tells whether a zone is within its dirty limits
- * @zone: the zone to check
+ * node_dirty_ok - tells whether a node is within its dirty limits
+ * @pgdat: the node to check
  *
- * Returns %true when the dirty pages in @zone are within the zone's
+ * Returns %true when the dirty pages in @pgdat are within the node's
  * dirty limit, %false if the limit is exceeded.
  */
-bool zone_dirty_ok(struct zone *zone)
+bool node_dirty_ok(struct pglist_data *pgdat)
 {
-	unsigned long limit = zone_dirty_limit(zone);
+	int z;
+	unsigned long limit = node_dirty_limit(pgdat);
+	unsigned long nr_pages = 0;
+
+	for (z = 0; z < MAX_NR_ZONES; z++) {
+		struct zone *zone = pgdat->node_zones + z;
+
+		if (!populated_zone(zone))
+			continue;
+
+		nr_pages += zone_page_state(zone, NR_FILE_DIRTY);
+		nr_pages += zone_page_state(zone, NR_UNSTABLE_NFS);
+		nr_pages += zone_page_state(zone, NR_WRITEBACK);
+	}
 
-	return zone_page_state(zone, NR_FILE_DIRTY) +
-	       zone_page_state(zone, NR_UNSTABLE_NFS) +
-	       zone_page_state(zone, NR_WRITEBACK) <= limit;
+	return nr_pages <= limit;
 }
 
 int dirty_background_ratio_handler(struct ctl_table *table, int write,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8215c51d5b23..9e113a6ff9a0 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2955,31 +2955,24 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
 		}
 		/*
 		 * When allocating a page cache page for writing, we
-		 * want to get it from a zone that is within its dirty
-		 * limit, such that no single zone holds more than its
+		 * want to get it from a node that is within its dirty
+		 * limit, such that no single node holds more than its
 		 * proportional share of globally allowed dirty pages.
-		 * The dirty limits take into account the zone's
+		 * The dirty limits take into account the node's
 		 * lowmem reserves and high watermark so that kswapd
 		 * should be able to balance it without having to
 		 * write pages from its LRU list.
 		 *
-		 * This may look like it could increase pressure on
-		 * lower zones by failing allocations in higher zones
-		 * before they are full.  But the pages that do spill
-		 * over are limited as the lower zones are protected
-		 * by this very same mechanism.  It should not become
-		 * a practical burden to them.
-		 *
 		 * XXX: For now, allow allocations to potentially
-		 * exceed the per-zone dirty limit in the slowpath
+		 * exceed the per-node dirty limit in the slowpath
 		 * (spread_dirty_pages unset) before going into reclaim,
 		 * which is important when on a NUMA setup the allowed
-		 * zones are together not big enough to reach the
+		 * nodes are together not big enough to reach the
 		 * global limit.  The proper fix for these situations
-		 * will require awareness of zones in the
+		 * will require awareness of nodes in the
 		 * dirty-throttling and the flusher threads.
 		 */
-		if (ac->spread_dirty_pages && !zone_dirty_ok(zone))
+		if (ac->spread_dirty_pages && !node_dirty_ok(zone->zone_pgdat))
 			continue;
 
 		mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
@@ -6749,6 +6742,9 @@ static void calculate_totalreserve_pages(void)
 	enum zone_type i, j;
 
 	for_each_online_pgdat(pgdat) {
+
+		pgdat->totalreserve_pages = 0;
+
 		for (i = 0; i < MAX_NR_ZONES; i++) {
 			struct zone *zone = pgdat->node_zones + i;
 			long max = 0;
@@ -6765,7 +6761,7 @@ static void calculate_totalreserve_pages(void)
 			if (max > zone->managed_pages)
 				max = zone->managed_pages;
 
-			zone->totalreserve_pages = max;
+			pgdat->totalreserve_pages += max;
 
 			reserve_pages += max;
 		}
-- 
2.6.4

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#1439232 — [PATCH 20/34] mm: move vmscan writes and file write accounting to the node

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 20/34] mm: move vmscan writes and file write accounting to the node
Message-ID<rSAqn-2Tv-49@gated-at.bofh.it>
In reply to#1439225
As reclaim is now node-based, it follows that page write activity due to
page reclaim should also be accounted for on the node.  For consistency,
also account page writes and page dirtying on a per-node basis.

After this patch, there are a few remaining zone counters that may appear
strange but are fine.  NUMA stats are still per-zone as this is a
user-space interface that tools consume.  NR_MLOCK, NR_SLAB_*,
NR_PAGETABLE, NR_KERNEL_STACK and NR_BOUNCE are all allocations that
potentially pin low memory and cannot trivially be reclaimed on demand.
This information is still useful for debugging a page allocation failure
warning.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
---
 include/linux/mmzone.h           | 8 ++++----
 include/trace/events/writeback.h | 4 ++--
 mm/page-writeback.c              | 6 +++---
 mm/vmscan.c                      | 4 ++--
 mm/vmstat.c                      | 8 ++++----
 5 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index acd4665c3025..e3d6d42722a0 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -122,10 +122,6 @@ enum zone_stat_item {
 	NR_KERNEL_STACK,
 	/* Second 128 byte cacheline */
 	NR_BOUNCE,
-	NR_VMSCAN_WRITE,
-	NR_VMSCAN_IMMEDIATE,	/* Prioritise for reclaim when writeback ends */
-	NR_DIRTIED,		/* page dirtyings since bootup */
-	NR_WRITTEN,		/* page writings since bootup */
 #if IS_ENABLED(CONFIG_ZSMALLOC)
 	NR_ZSPAGES,		/* allocated in zsmalloc */
 #endif
@@ -165,6 +161,10 @@ enum node_stat_item {
 	NR_SHMEM_PMDMAPPED,
 	NR_ANON_THPS,
 	NR_UNSTABLE_NFS,	/* NFS unstable pages */
+	NR_VMSCAN_WRITE,
+	NR_VMSCAN_IMMEDIATE,	/* Prioritise for reclaim when writeback ends */
+	NR_DIRTIED,		/* page dirtyings since bootup */
+	NR_WRITTEN,		/* page writings since bootup */
 	NR_VM_NODE_STAT_ITEMS
 };
 
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index ad20f2d2b1f9..2ccd9ccbf9ef 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -415,8 +415,8 @@ TRACE_EVENT(global_dirty_state,
 		__entry->nr_dirty	= global_node_page_state(NR_FILE_DIRTY);
 		__entry->nr_writeback	= global_node_page_state(NR_WRITEBACK);
 		__entry->nr_unstable	= global_node_page_state(NR_UNSTABLE_NFS);
-		__entry->nr_dirtied	= global_page_state(NR_DIRTIED);
-		__entry->nr_written	= global_page_state(NR_WRITTEN);
+		__entry->nr_dirtied	= global_node_page_state(NR_DIRTIED);
+		__entry->nr_written	= global_node_page_state(NR_WRITTEN);
 		__entry->background_thresh = background_thresh;
 		__entry->dirty_thresh	= dirty_thresh;
 		__entry->dirty_limit	= global_wb_domain.dirty_limit;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index f97591d9fa00..3c02aa603f5a 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2461,7 +2461,7 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 		mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_DIRTY);
 		__inc_node_page_state(page, NR_FILE_DIRTY);
 		__inc_zone_page_state(page, NR_ZONE_WRITE_PENDING);
-		__inc_zone_page_state(page, NR_DIRTIED);
+		__inc_node_page_state(page, NR_DIRTIED);
 		__inc_wb_stat(wb, WB_RECLAIMABLE);
 		__inc_wb_stat(wb, WB_DIRTIED);
 		task_io_account_write(PAGE_SIZE);
@@ -2550,7 +2550,7 @@ void account_page_redirty(struct page *page)
 
 		wb = unlocked_inode_to_wb_begin(inode, &locked);
 		current->nr_dirtied--;
-		dec_zone_page_state(page, NR_DIRTIED);
+		dec_node_page_state(page, NR_DIRTIED);
 		dec_wb_stat(wb, WB_DIRTIED);
 		unlocked_inode_to_wb_end(inode, locked);
 	}
@@ -2787,7 +2787,7 @@ int test_clear_page_writeback(struct page *page)
 		mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
 		dec_node_page_state(page, NR_WRITEBACK);
 		dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
-		inc_zone_page_state(page, NR_WRITTEN);
+		inc_node_page_state(page, NR_WRITTEN);
 	}
 	unlock_page_memcg(page);
 	return ret;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index aef2a6245657..5ad670881d8d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -612,7 +612,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
 			ClearPageReclaim(page);
 		}
 		trace_mm_vmscan_writepage(page);
-		inc_zone_page_state(page, NR_VMSCAN_WRITE);
+		inc_node_page_state(page, NR_VMSCAN_WRITE);
 		return PAGE_SUCCESS;
 	}
 
@@ -1117,7 +1117,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 				 * except we already have the page isolated
 				 * and know it's dirty
 				 */
-				inc_zone_page_state(page, NR_VMSCAN_IMMEDIATE);
+				inc_node_page_state(page, NR_VMSCAN_IMMEDIATE);
 				SetPageReclaim(page);
 
 				goto keep_locked;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 455392158062..bc94968400d0 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -931,10 +931,6 @@ const char * const vmstat_text[] = {
 	"nr_page_table_pages",
 	"nr_kernel_stack",
 	"nr_bounce",
-	"nr_vmscan_write",
-	"nr_vmscan_immediate_reclaim",
-	"nr_dirtied",
-	"nr_written",
 #if IS_ENABLED(CONFIG_ZSMALLOC)
 	"nr_zspages",
 #endif
@@ -971,6 +967,10 @@ const char * const vmstat_text[] = {
 	"nr_shmem_pmdmapped",
 	"nr_anon_transparent_hugepages",
 	"nr_unstable",
+	"nr_vmscan_write",
+	"nr_vmscan_immediate_reclaim",
+	"nr_dirtied",
+	"nr_written",
 
 	/* enum writeback_stat_item counters */
 	"nr_dirty_threshold",
-- 
2.6.4

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#1439233 — [PATCH 12/34] mm: vmscan: do not reclaim from kswapd if there is any eligible zone

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 12/34] mm: vmscan: do not reclaim from kswapd if there is any eligible zone
Message-ID<rSAqn-2Tv-51@gated-at.bofh.it>
In reply to#1439225
kswapd scans from highest to lowest for a zone that requires balancing.
This was necessary when reclaim was per-zone to fairly age pages on lower
zones.  Now that we are reclaiming on a per-node basis, any eligible zone
can be used and pages will still be aged fairly.  This patch avoids
reclaiming excessively unless buffer_heads are over the limit and it's
necessary to reclaim from a higher zone than requested by the waker of
kswapd to relieve low memory pressure.

[hillf.zj@alibaba-inc.com: Force kswapd reclaim no more than needed]
Link: http://lkml.kernel.org/r/1466518566-30034-12-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/vmscan.c | 59 +++++++++++++++++++++++++++--------------------------------
 1 file changed, 27 insertions(+), 32 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8b39b903bd14..b7a276f4b1b0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3144,31 +3144,39 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 
 		sc.nr_reclaimed = 0;
 
-		/* Scan from the highest requested zone to dma */
-		for (i = classzone_idx; i >= 0; i--) {
-			zone = pgdat->node_zones + i;
-			if (!populated_zone(zone))
-				continue;
-
-			/*
-			 * If the number of buffer_heads in the machine
-			 * exceeds the maximum allowed level and this node
-			 * has a highmem zone, force kswapd to reclaim from
-			 * it to relieve lowmem pressure.
-			 */
-			if (buffer_heads_over_limit && is_highmem_idx(i)) {
-				classzone_idx = i;
-				break;
-			}
+		/*
+		 * If the number of buffer_heads in the machine exceeds the
+		 * maximum allowed level then reclaim from all zones. This is
+		 * not specific to highmem as highmem may not exist but it is
+		 * it is expected that buffer_heads are stripped in writeback.
+		 */
+		if (buffer_heads_over_limit) {
+			for (i = MAX_NR_ZONES - 1; i >= 0; i--) {
+				zone = pgdat->node_zones + i;
+				if (!populated_zone(zone))
+					continue;
 
-			if (!zone_balanced(zone, order, 0)) {
 				classzone_idx = i;
 				break;
 			}
 		}
 
-		if (i < 0)
-			goto out;
+		/*
+		 * Only reclaim if there are no eligible zones. Check from
+		 * high to low zone as allocations prefer higher zones.
+		 * Scanning from low to high zone would allow congestion to be
+		 * cleared during a very small window when a small low
+		 * zone was balanced even under extreme pressure when the
+		 * overall node may be congested.
+		 */
+		for (i = classzone_idx; i >= 0; i--) {
+			zone = pgdat->node_zones + i;
+			if (!populated_zone(zone))
+				continue;
+
+			if (zone_balanced(zone, sc.order, classzone_idx))
+				goto out;
+		}
 
 		/*
 		 * Do some background aging of the anon list, to give
@@ -3214,19 +3222,6 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 			break;
 
 		/*
-		 * Stop reclaiming if any eligible zone is balanced and clear
-		 * node writeback or congested.
-		 */
-		for (i = 0; i <= classzone_idx; i++) {
-			zone = pgdat->node_zones + i;
-			if (!populated_zone(zone))
-				continue;
-
-			if (zone_balanced(zone, sc.order, classzone_idx))
-				goto out;
-		}
-
-		/*
 		 * Raise priority if scanning rate is too low or there was no
 		 * progress in reclaiming pages
 		 */
-- 
2.6.4

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#1439234 — [PATCH 24/34] mm, vmscan: avoid passing in classzone_idx unnecessarily to shrink_node

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 24/34] mm, vmscan: avoid passing in classzone_idx unnecessarily to shrink_node
Message-ID<rSAqn-2Tv-53@gated-at.bofh.it>
In reply to#1439225
shrink_node receives all information it needs about classzone_idx
from sc->reclaim_idx so remove the aliases.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
---
 mm/vmscan.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index e12b0fd2044c..bba71b6c9a4c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2426,8 +2426,7 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat,
 	return true;
 }
 
-static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
-			enum zone_type classzone_idx)
+static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
 {
 	struct reclaim_state *reclaim_state = current->reclaim_state;
 	unsigned long nr_reclaimed, nr_scanned;
@@ -2656,7 +2655,7 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 		if (zone->zone_pgdat == last_pgdat)
 			continue;
 		last_pgdat = zone->zone_pgdat;
-		shrink_node(zone->zone_pgdat, sc, classzone_idx);
+		shrink_node(zone->zone_pgdat, sc);
 	}
 
 	/*
@@ -3080,7 +3079,6 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining,
  * This is used to determine if the scanning priority needs to be raised.
  */
 static bool kswapd_shrink_node(pg_data_t *pgdat,
-			       int classzone_idx,
 			       struct scan_control *sc)
 {
 	struct zone *zone;
@@ -3088,7 +3086,7 @@ static bool kswapd_shrink_node(pg_data_t *pgdat,
 
 	/* Reclaim a number of pages proportional to the number of zones */
 	sc->nr_to_reclaim = 0;
-	for (z = 0; z <= classzone_idx; z++) {
+	for (z = 0; z <= sc->reclaim_idx; z++) {
 		zone = pgdat->node_zones + z;
 		if (!populated_zone(zone))
 			continue;
@@ -3100,7 +3098,7 @@ static bool kswapd_shrink_node(pg_data_t *pgdat,
 	 * Historically care was taken to put equal pressure on all zones but
 	 * now pressure is applied based on node LRU order.
 	 */
-	shrink_node(pgdat, sc, classzone_idx);
+	shrink_node(pgdat, sc);
 
 	/*
 	 * Fragmentation may mean that the system cannot be rebalanced for
@@ -3162,7 +3160,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 				if (!populated_zone(zone))
 					continue;
 
-				classzone_idx = i;
+				sc.reclaim_idx = i;
 				break;
 			}
 		}
@@ -3175,12 +3173,12 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 		 * zone was balanced even under extreme pressure when the
 		 * overall node may be congested.
 		 */
-		for (i = classzone_idx; i >= 0; i--) {
+		for (i = sc.reclaim_idx; i >= 0; i--) {
 			zone = pgdat->node_zones + i;
 			if (!populated_zone(zone))
 				continue;
 
-			if (zone_balanced(zone, sc.order, classzone_idx))
+			if (zone_balanced(zone, sc.order, sc.reclaim_idx))
 				goto out;
 		}
 
@@ -3211,7 +3209,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 		 * enough pages are already being scanned that that high
 		 * watermark would be met at 100% efficiency.
 		 */
-		if (kswapd_shrink_node(pgdat, classzone_idx, &sc))
+		if (kswapd_shrink_node(pgdat, &sc))
 			raise_priority = false;
 
 		/*
@@ -3674,7 +3672,7 @@ static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned in
 		 * priorities until we have enough memory freed.
 		 */
 		do {
-			shrink_node(pgdat, &sc, classzone_idx);
+			shrink_node(pgdat, &sc);
 		} while (sc.nr_reclaimed < nr_pages && --sc.priority >= 0);
 	}
 
-- 
2.6.4

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#1439235 — [PATCH 14/34] mm, memcg: move memcg limit enforcement from zones to nodes

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 14/34] mm, memcg: move memcg limit enforcement from zones to nodes
Message-ID<rSAqm-2Tv-29@gated-at.bofh.it>
In reply to#1439225
Memcg needs adjustment after moving LRUs to the node. Limits are tracked
per memcg but the soft-limit excess is tracked per zone. As global page
reclaim is based on the node, it is easy to imagine a situation where
a zone soft limit is exceeded even though the memcg limit is fine.

This patch moves the soft limit tree the node.  Technically, all the variable
names should also change but people are already familiar by the meaning of
"mz" even if "mn" would be a more appropriate name now.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
---
 include/linux/memcontrol.h |  38 ++++-----
 include/linux/swap.h       |   2 +-
 mm/memcontrol.c            | 190 ++++++++++++++++++++-------------------------
 mm/vmscan.c                |  19 +++--
 mm/workingset.c            |   6 +-
 5 files changed, 111 insertions(+), 144 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index c13227d018f2..80bf8458148a 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -61,7 +61,7 @@ enum mem_cgroup_stat_index {
 };
 
 struct mem_cgroup_reclaim_cookie {
-	struct zone *zone;
+	pg_data_t *pgdat;
 	int priority;
 	unsigned int generation;
 };
@@ -119,7 +119,7 @@ struct mem_cgroup_reclaim_iter {
 /*
  * per-zone information in memory controller.
  */
-struct mem_cgroup_per_zone {
+struct mem_cgroup_per_node {
 	struct lruvec		lruvec;
 	unsigned long		lru_size[NR_LRU_LISTS];
 
@@ -133,10 +133,6 @@ struct mem_cgroup_per_zone {
 						/* use container_of	   */
 };
 
-struct mem_cgroup_per_node {
-	struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
-};
-
 struct mem_cgroup_threshold {
 	struct eventfd_ctx *eventfd;
 	unsigned long threshold;
@@ -315,19 +311,15 @@ void mem_cgroup_uncharge_list(struct list_head *page_list);
 
 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);
 
-static inline struct mem_cgroup_per_zone *
-mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone)
+static struct mem_cgroup_per_node *
+mem_cgroup_nodeinfo(struct mem_cgroup *memcg, int nid)
 {
-	int nid = zone_to_nid(zone);
-	int zid = zone_idx(zone);
-
-	return &memcg->nodeinfo[nid]->zoneinfo[zid];
+	return memcg->nodeinfo[nid];
 }
 
 /**
  * mem_cgroup_lruvec - get the lru list vector for a node or a memcg zone
  * @node: node of the wanted lruvec
- * @zone: zone of the wanted lruvec
  * @memcg: memcg of the wanted lruvec
  *
  * Returns the lru list vector holding pages for a given @node or a given
@@ -335,9 +327,9 @@ mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone)
  * is disabled.
  */
 static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
-				struct zone *zone, struct mem_cgroup *memcg)
+				struct mem_cgroup *memcg)
 {
-	struct mem_cgroup_per_zone *mz;
+	struct mem_cgroup_per_node *mz;
 	struct lruvec *lruvec;
 
 	if (mem_cgroup_disabled()) {
@@ -345,7 +337,7 @@ static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
 		goto out;
 	}
 
-	mz = mem_cgroup_zone_zoneinfo(memcg, zone);
+	mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
 	lruvec = &mz->lruvec;
 out:
 	/*
@@ -353,8 +345,8 @@ static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
 	 * we have to be prepared to initialize lruvec->pgdat here;
 	 * and if offlined then reonlined, we need to reinitialize it.
 	 */
-	if (unlikely(lruvec->pgdat != zone->zone_pgdat))
-		lruvec->pgdat = zone->zone_pgdat;
+	if (unlikely(lruvec->pgdat != pgdat))
+		lruvec->pgdat = pgdat;
 	return lruvec;
 }
 
@@ -447,9 +439,9 @@ unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
 static inline
 unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
 {
-	struct mem_cgroup_per_zone *mz;
+	struct mem_cgroup_per_node *mz;
 
-	mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
+	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 	return mz->lru_size[lru];
 }
 
@@ -520,7 +512,7 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
 	mem_cgroup_update_page_stat(page, idx, -1);
 }
 
-unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
+unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 						gfp_t gfp_mask,
 						unsigned long *total_scanned);
 
@@ -612,7 +604,7 @@ static inline void mem_cgroup_migrate(struct page *old, struct page *new)
 }
 
 static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
-				struct zone *zone, struct mem_cgroup *memcg)
+				struct mem_cgroup *memcg)
 {
 	return node_lruvec(pgdat);
 }
@@ -724,7 +716,7 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
 }
 
 static inline
-unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
+unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 					    gfp_t gfp_mask,
 					    unsigned long *total_scanned)
 {
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 0ad616d7c381..2a23ddc96edd 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -318,7 +318,7 @@ extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 						  bool may_swap);
 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
 						gfp_t gfp_mask, bool noswap,
-						struct zone *zone,
+						pg_data_t *pgdat,
 						unsigned long *nr_scanned);
 extern unsigned long shrink_all_memory(unsigned long nr_pages);
 extern int vm_swappiness;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c9ebec98e92a..9cbd40ebccd1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -132,15 +132,11 @@ static const char * const mem_cgroup_lru_names[] = {
  * their hierarchy representation
  */
 
-struct mem_cgroup_tree_per_zone {
+struct mem_cgroup_tree_per_node {
 	struct rb_root rb_root;
 	spinlock_t lock;
 };
 
-struct mem_cgroup_tree_per_node {
-	struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
-};
-
 struct mem_cgroup_tree {
 	struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
 };
@@ -374,37 +370,35 @@ ino_t page_cgroup_ino(struct page *page)
 	return ino;
 }
 
-static struct mem_cgroup_per_zone *
-mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page)
+static struct mem_cgroup_per_node *
+mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page)
 {
 	int nid = page_to_nid(page);
-	int zid = page_zonenum(page);
 
-	return &memcg->nodeinfo[nid]->zoneinfo[zid];
+	return memcg->nodeinfo[nid];
 }
 
-static struct mem_cgroup_tree_per_zone *
-soft_limit_tree_node_zone(int nid, int zid)
+static struct mem_cgroup_tree_per_node *
+soft_limit_tree_node(int nid)
 {
-	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
+	return soft_limit_tree.rb_tree_per_node[nid];
 }
 
-static struct mem_cgroup_tree_per_zone *
+static struct mem_cgroup_tree_per_node *
 soft_limit_tree_from_page(struct page *page)
 {
 	int nid = page_to_nid(page);
-	int zid = page_zonenum(page);
 
-	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
+	return soft_limit_tree.rb_tree_per_node[nid];
 }
 
-static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone *mz,
-					 struct mem_cgroup_tree_per_zone *mctz,
+static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
+					 struct mem_cgroup_tree_per_node *mctz,
 					 unsigned long new_usage_in_excess)
 {
 	struct rb_node **p = &mctz->rb_root.rb_node;
 	struct rb_node *parent = NULL;
-	struct mem_cgroup_per_zone *mz_node;
+	struct mem_cgroup_per_node *mz_node;
 
 	if (mz->on_tree)
 		return;
@@ -414,7 +408,7 @@ static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone *mz,
 		return;
 	while (*p) {
 		parent = *p;
-		mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
+		mz_node = rb_entry(parent, struct mem_cgroup_per_node,
 					tree_node);
 		if (mz->usage_in_excess < mz_node->usage_in_excess)
 			p = &(*p)->rb_left;
@@ -430,8 +424,8 @@ static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone *mz,
 	mz->on_tree = true;
 }
 
-static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
-					 struct mem_cgroup_tree_per_zone *mctz)
+static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
+					 struct mem_cgroup_tree_per_node *mctz)
 {
 	if (!mz->on_tree)
 		return;
@@ -439,8 +433,8 @@ static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
 	mz->on_tree = false;
 }
 
-static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
-				       struct mem_cgroup_tree_per_zone *mctz)
+static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
+				       struct mem_cgroup_tree_per_node *mctz)
 {
 	unsigned long flags;
 
@@ -464,8 +458,8 @@ static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
 {
 	unsigned long excess;
-	struct mem_cgroup_per_zone *mz;
-	struct mem_cgroup_tree_per_zone *mctz;
+	struct mem_cgroup_per_node *mz;
+	struct mem_cgroup_tree_per_node *mctz;
 
 	mctz = soft_limit_tree_from_page(page);
 	/*
@@ -473,7 +467,7 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
 	 * because their event counter is not touched.
 	 */
 	for (; memcg; memcg = parent_mem_cgroup(memcg)) {
-		mz = mem_cgroup_page_zoneinfo(memcg, page);
+		mz = mem_cgroup_page_nodeinfo(memcg, page);
 		excess = soft_limit_excess(memcg);
 		/*
 		 * We have to update the tree if mz is on RB-tree or
@@ -498,24 +492,22 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
 
 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
 {
-	struct mem_cgroup_tree_per_zone *mctz;
-	struct mem_cgroup_per_zone *mz;
-	int nid, zid;
+	struct mem_cgroup_tree_per_node *mctz;
+	struct mem_cgroup_per_node *mz;
+	int nid;
 
 	for_each_node(nid) {
-		for (zid = 0; zid < MAX_NR_ZONES; zid++) {
-			mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
-			mctz = soft_limit_tree_node_zone(nid, zid);
-			mem_cgroup_remove_exceeded(mz, mctz);
-		}
+		mz = mem_cgroup_nodeinfo(memcg, nid);
+		mctz = soft_limit_tree_node(nid);
+		mem_cgroup_remove_exceeded(mz, mctz);
 	}
 }
 
-static struct mem_cgroup_per_zone *
-__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
+static struct mem_cgroup_per_node *
+__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
 {
 	struct rb_node *rightmost = NULL;
-	struct mem_cgroup_per_zone *mz;
+	struct mem_cgroup_per_node *mz;
 
 retry:
 	mz = NULL;
@@ -523,7 +515,7 @@ __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
 	if (!rightmost)
 		goto done;		/* Nothing to reclaim from */
 
-	mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
+	mz = rb_entry(rightmost, struct mem_cgroup_per_node, tree_node);
 	/*
 	 * Remove the node now but someone else can add it back,
 	 * we will to add it back at the end of reclaim to its correct
@@ -537,10 +529,10 @@ __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
 	return mz;
 }
 
-static struct mem_cgroup_per_zone *
-mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
+static struct mem_cgroup_per_node *
+mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
 {
-	struct mem_cgroup_per_zone *mz;
+	struct mem_cgroup_per_node *mz;
 
 	spin_lock_irq(&mctz->lock);
 	mz = __mem_cgroup_largest_soft_limit_node(mctz);
@@ -634,20 +626,16 @@ unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
 					   int nid, unsigned int lru_mask)
 {
 	unsigned long nr = 0;
-	int zid;
+	struct mem_cgroup_per_node *mz;
+	enum lru_list lru;
 
 	VM_BUG_ON((unsigned)nid >= nr_node_ids);
 
-	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
-		struct mem_cgroup_per_zone *mz;
-		enum lru_list lru;
-
-		for_each_lru(lru) {
-			if (!(BIT(lru) & lru_mask))
-				continue;
-			mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
-			nr += mz->lru_size[lru];
-		}
+	for_each_lru(lru) {
+		if (!(BIT(lru) & lru_mask))
+			continue;
+		mz = mem_cgroup_nodeinfo(memcg, nid);
+		nr += mz->lru_size[lru];
 	}
 	return nr;
 }
@@ -800,9 +788,9 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
 	rcu_read_lock();
 
 	if (reclaim) {
-		struct mem_cgroup_per_zone *mz;
+		struct mem_cgroup_per_node *mz;
 
-		mz = mem_cgroup_zone_zoneinfo(root, reclaim->zone);
+		mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id);
 		iter = &mz->iter[reclaim->priority];
 
 		if (prev && reclaim->generation != iter->generation)
@@ -901,19 +889,17 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
 {
 	struct mem_cgroup *memcg = dead_memcg;
 	struct mem_cgroup_reclaim_iter *iter;
-	struct mem_cgroup_per_zone *mz;
-	int nid, zid;
+	struct mem_cgroup_per_node *mz;
+	int nid;
 	int i;
 
 	while ((memcg = parent_mem_cgroup(memcg))) {
 		for_each_node(nid) {
-			for (zid = 0; zid < MAX_NR_ZONES; zid++) {
-				mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
-				for (i = 0; i <= DEF_PRIORITY; i++) {
-					iter = &mz->iter[i];
-					cmpxchg(&iter->position,
-						dead_memcg, NULL);
-				}
+			mz = mem_cgroup_nodeinfo(memcg, nid);
+			for (i = 0; i <= DEF_PRIORITY; i++) {
+				iter = &mz->iter[i];
+				cmpxchg(&iter->position,
+					dead_memcg, NULL);
 			}
 		}
 	}
@@ -945,7 +931,7 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
  */
 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
 {
-	struct mem_cgroup_per_zone *mz;
+	struct mem_cgroup_per_node *mz;
 	struct mem_cgroup *memcg;
 	struct lruvec *lruvec;
 
@@ -962,7 +948,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
 	if (!memcg)
 		memcg = root_mem_cgroup;
 
-	mz = mem_cgroup_page_zoneinfo(memcg, page);
+	mz = mem_cgroup_page_nodeinfo(memcg, page);
 	lruvec = &mz->lruvec;
 out:
 	/*
@@ -989,7 +975,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
 				enum zone_type zid, int nr_pages)
 {
-	struct mem_cgroup_per_zone *mz;
+	struct mem_cgroup_per_node *mz;
 	unsigned long *lru_size;
 	long size;
 	bool empty;
@@ -999,7 +985,7 @@ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
 	if (mem_cgroup_disabled())
 		return;
 
-	mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
+	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 	lru_size = mz->lru_size + lru;
 	empty = list_empty(lruvec->lists + lru);
 
@@ -1392,7 +1378,7 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
 #endif
 
 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
-				   struct zone *zone,
+				   pg_data_t *pgdat,
 				   gfp_t gfp_mask,
 				   unsigned long *total_scanned)
 {
@@ -1402,7 +1388,7 @@ static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
 	unsigned long excess;
 	unsigned long nr_scanned;
 	struct mem_cgroup_reclaim_cookie reclaim = {
-		.zone = zone,
+		.pgdat = pgdat,
 		.priority = 0,
 	};
 
@@ -1433,7 +1419,7 @@ static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
 			continue;
 		}
 		total += mem_cgroup_shrink_node(victim, gfp_mask, false,
-					zone, &nr_scanned);
+					pgdat, &nr_scanned);
 		*total_scanned += nr_scanned;
 		if (!soft_limit_excess(root_memcg))
 			break;
@@ -2560,22 +2546,22 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
 	return ret;
 }
 
-unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
+unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 					    gfp_t gfp_mask,
 					    unsigned long *total_scanned)
 {
 	unsigned long nr_reclaimed = 0;
-	struct mem_cgroup_per_zone *mz, *next_mz = NULL;
+	struct mem_cgroup_per_node *mz, *next_mz = NULL;
 	unsigned long reclaimed;
 	int loop = 0;
-	struct mem_cgroup_tree_per_zone *mctz;
+	struct mem_cgroup_tree_per_node *mctz;
 	unsigned long excess;
 	unsigned long nr_scanned;
 
 	if (order > 0)
 		return 0;
 
-	mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
+	mctz = soft_limit_tree_node(pgdat->node_id);
 	/*
 	 * This loop can run a while, specially if mem_cgroup's continuously
 	 * keep exceeding their soft limit and putting the system under
@@ -2590,7 +2576,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 			break;
 
 		nr_scanned = 0;
-		reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
+		reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
 						    gfp_mask, &nr_scanned);
 		nr_reclaimed += reclaimed;
 		*total_scanned += nr_scanned;
@@ -3211,22 +3197,21 @@ static int memcg_stat_show(struct seq_file *m, void *v)
 
 #ifdef CONFIG_DEBUG_VM
 	{
-		int nid, zid;
-		struct mem_cgroup_per_zone *mz;
+		pg_data_t *pgdat;
+		struct mem_cgroup_per_node *mz;
 		struct zone_reclaim_stat *rstat;
 		unsigned long recent_rotated[2] = {0, 0};
 		unsigned long recent_scanned[2] = {0, 0};
 
-		for_each_online_node(nid)
-			for (zid = 0; zid < MAX_NR_ZONES; zid++) {
-				mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
-				rstat = &mz->lruvec.reclaim_stat;
+		for_each_online_pgdat(pgdat) {
+			mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
+			rstat = &mz->lruvec.reclaim_stat;
 
-				recent_rotated[0] += rstat->recent_rotated[0];
-				recent_rotated[1] += rstat->recent_rotated[1];
-				recent_scanned[0] += rstat->recent_scanned[0];
-				recent_scanned[1] += rstat->recent_scanned[1];
-			}
+			recent_rotated[0] += rstat->recent_rotated[0];
+			recent_rotated[1] += rstat->recent_rotated[1];
+			recent_scanned[0] += rstat->recent_scanned[0];
+			recent_scanned[1] += rstat->recent_scanned[1];
+		}
 		seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
 		seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
 		seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
@@ -4106,11 +4091,10 @@ struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
 	return idr_find(&mem_cgroup_idr, id);
 }
 
-static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
+static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
 {
 	struct mem_cgroup_per_node *pn;
-	struct mem_cgroup_per_zone *mz;
-	int zone, tmp = node;
+	int tmp = node;
 	/*
 	 * This routine is called against possible nodes.
 	 * But it's BUG to call kmalloc() against offline node.
@@ -4125,18 +4109,16 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
 	if (!pn)
 		return 1;
 
-	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
-		mz = &pn->zoneinfo[zone];
-		lruvec_init(&mz->lruvec);
-		mz->usage_in_excess = 0;
-		mz->on_tree = false;
-		mz->memcg = memcg;
-	}
+	lruvec_init(&pn->lruvec);
+	pn->usage_in_excess = 0;
+	pn->on_tree = false;
+	pn->memcg = memcg;
+
 	memcg->nodeinfo[node] = pn;
 	return 0;
 }
 
-static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
+static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
 {
 	kfree(memcg->nodeinfo[node]);
 }
@@ -4147,7 +4129,7 @@ static void mem_cgroup_free(struct mem_cgroup *memcg)
 
 	memcg_wb_domain_exit(memcg);
 	for_each_node(node)
-		free_mem_cgroup_per_zone_info(memcg, node);
+		free_mem_cgroup_per_node_info(memcg, node);
 	free_percpu(memcg->stat);
 	kfree(memcg);
 }
@@ -4176,7 +4158,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
 		goto fail;
 
 	for_each_node(node)
-		if (alloc_mem_cgroup_per_zone_info(memcg, node))
+		if (alloc_mem_cgroup_per_node_info(memcg, node))
 			goto fail;
 
 	if (memcg_wb_domain_init(memcg, GFP_KERNEL))
@@ -5779,18 +5761,12 @@ static int __init mem_cgroup_init(void)
 
 	for_each_node(node) {
 		struct mem_cgroup_tree_per_node *rtpn;
-		int zone;
 
 		rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
 				    node_online(node) ? node : NUMA_NO_NODE);
 
-		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
-			struct mem_cgroup_tree_per_zone *rtpz;
-
-			rtpz = &rtpn->rb_tree_per_zone[zone];
-			rtpz->rb_root = RB_ROOT;
-			spin_lock_init(&rtpz->lock);
-		}
+		rtpn->rb_root = RB_ROOT;
+		spin_lock_init(&rtpn->lock);
 		soft_limit_tree.rb_tree_per_node[node] = rtpn;
 	}
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f0bea68b8780..8d2555dd3ef3 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2229,8 +2229,7 @@ static inline void init_tlb_ubc(void)
 static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memcg,
 			      struct scan_control *sc, unsigned long *lru_pages)
 {
-	struct zone *zone = &pgdat->node_zones[sc->reclaim_idx];
-	struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, zone, memcg);
+	struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, memcg);
 	unsigned long nr[NR_LRU_LISTS];
 	unsigned long targets[NR_LRU_LISTS];
 	unsigned long nr_to_scan;
@@ -2437,7 +2436,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
 	do {
 		struct mem_cgroup *root = sc->target_mem_cgroup;
 		struct mem_cgroup_reclaim_cookie reclaim = {
-			.zone = &pgdat->node_zones[classzone_idx],
+			.pgdat = pgdat,
 			.priority = sc->priority,
 		};
 		unsigned long node_lru_pages = 0;
@@ -2645,7 +2644,7 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 			 * and balancing, not for a memcg's limit.
 			 */
 			nr_soft_scanned = 0;
-			nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone,
+			nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone->zone_pgdat,
 						sc->order, sc->gfp_mask,
 						&nr_soft_scanned);
 			sc->nr_reclaimed += nr_soft_reclaimed;
@@ -2915,7 +2914,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 
 unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
 						gfp_t gfp_mask, bool noswap,
-						struct zone *zone,
+						pg_data_t *pgdat,
 						unsigned long *nr_scanned)
 {
 	struct scan_control sc = {
@@ -2942,7 +2941,7 @@ unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
 	 * will pick up pages from other mem cgroup's as well. We hack
 	 * the priority and make it zero.
 	 */
-	shrink_node_memcg(zone->zone_pgdat, memcg, &sc, &lru_pages);
+	shrink_node_memcg(pgdat, memcg, &sc, &lru_pages);
 
 	trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);
 
@@ -2992,7 +2991,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 #endif
 
 static void age_active_anon(struct pglist_data *pgdat,
-				struct zone *zone, struct scan_control *sc)
+				struct scan_control *sc)
 {
 	struct mem_cgroup *memcg;
 
@@ -3001,7 +3000,7 @@ static void age_active_anon(struct pglist_data *pgdat,
 
 	memcg = mem_cgroup_iter(NULL, NULL, NULL);
 	do {
-		struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, zone, memcg);
+		struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, memcg);
 
 		if (inactive_list_is_low(lruvec, false))
 			shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
@@ -3191,7 +3190,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 		 * pages are rotated regardless of classzone as this is
 		 * about consistent aging.
 		 */
-		age_active_anon(pgdat, &pgdat->node_zones[MAX_NR_ZONES - 1], &sc);
+		age_active_anon(pgdat, &sc);
 
 		/*
 		 * If we're getting trouble reclaiming, start doing writepage
@@ -3203,7 +3202,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 		/* Call soft limit reclaim before calling shrink_node. */
 		sc.nr_scanned = 0;
 		nr_soft_scanned = 0;
-		nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone, sc.order,
+		nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(pgdat, sc.order,
 						sc.gfp_mask, &nr_soft_scanned);
 		sc.nr_reclaimed += nr_soft_reclaimed;
 
diff --git a/mm/workingset.c b/mm/workingset.c
index de68ad681585..9a1016f5d500 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -218,7 +218,7 @@ void *workingset_eviction(struct address_space *mapping, struct page *page)
 	VM_BUG_ON_PAGE(page_count(page), page);
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 
-	lruvec = mem_cgroup_lruvec(zone->zone_pgdat, zone, memcg);
+	lruvec = mem_cgroup_lruvec(zone->zone_pgdat, memcg);
 	eviction = atomic_long_inc_return(&lruvec->inactive_age);
 	return pack_shadow(memcgid, zone, eviction);
 }
@@ -267,7 +267,7 @@ bool workingset_refault(void *shadow)
 		rcu_read_unlock();
 		return false;
 	}
-	lruvec = mem_cgroup_lruvec(zone->zone_pgdat, zone, memcg);
+	lruvec = mem_cgroup_lruvec(zone->zone_pgdat, memcg);
 	refault = atomic_long_read(&lruvec->inactive_age);
 	active_file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE);
 	rcu_read_unlock();
@@ -319,7 +319,7 @@ void workingset_activation(struct page *page)
 	memcg = page_memcg_rcu(page);
 	if (!mem_cgroup_disabled() && !memcg)
 		goto out;
-	lruvec = mem_cgroup_lruvec(page_pgdat(page), page_zone(page), memcg);
+	lruvec = mem_cgroup_lruvec(page_pgdat(page), memcg);
 	atomic_long_inc(&lruvec->inactive_age);
 out:
 	rcu_read_unlock();
-- 
2.6.4

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#1439236 — [PATCH 04/34] mm, mmzone: clarify the usage of zone padding

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 04/34] mm, mmzone: clarify the usage of zone padding
Message-ID<rSAqm-2Tv-31@gated-at.bofh.it>
In reply to#1439225
Zone padding separates write-intensive fields used by page allocation,
compaction and vmstats but the comments are a little misleading and
need clarification.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
 include/linux/mmzone.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index d4f5cac0a8c3..edafdaf62e90 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -477,20 +477,21 @@ struct zone {
 	unsigned long		wait_table_hash_nr_entries;
 	unsigned long		wait_table_bits;
 
+	/* Write-intensive fields used from the page allocator */
 	ZONE_PADDING(_pad1_)
+
 	/* free areas of different sizes */
 	struct free_area	free_area[MAX_ORDER];
 
 	/* zone flags, see below */
 	unsigned long		flags;
 
-	/* Write-intensive fields used from the page allocator */
+	/* Primarily protects free_area */
 	spinlock_t		lock;
 
+	/* Write-intensive fields used by compaction and vmstats. */
 	ZONE_PADDING(_pad2_)
 
-	/* Write-intensive fields used by page reclaim */
-
 	/*
 	 * When free pages are below this point, additional steps are taken
 	 * when reading the number of free pages to avoid per-cpu counter
-- 
2.6.4

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#1439237 — [PATCH 02/34] mm, vmscan: move lru_lock to the node

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 02/34] mm, vmscan: move lru_lock to the node
Message-ID<rSAqm-2Tv-33@gated-at.bofh.it>
In reply to#1439225
Node-based reclaim requires node-based LRUs and locking.  This is a
preparation patch that just moves the lru_lock to the node so later
patches are easier to review.  It is a mechanical change but note this
patch makes contention worse because the LRU lock is hotter and direct
reclaim and kswapd can contend on the same lock even when reclaiming from
different zones.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Minchan Kim <minchan@kernel.org>
---
 Documentation/cgroup-v1/memcg_test.txt |  4 +--
 Documentation/cgroup-v1/memory.txt     |  4 +--
 include/linux/mm_types.h               |  2 +-
 include/linux/mmzone.h                 | 10 +++++--
 mm/compaction.c                        | 10 +++----
 mm/filemap.c                           |  4 +--
 mm/huge_memory.c                       |  6 ++---
 mm/memcontrol.c                        |  6 ++---
 mm/mlock.c                             | 10 +++----
 mm/page_alloc.c                        |  4 +--
 mm/page_idle.c                         |  4 +--
 mm/rmap.c                              |  2 +-
 mm/swap.c                              | 30 ++++++++++-----------
 mm/vmscan.c                            | 48 +++++++++++++++++-----------------
 14 files changed, 75 insertions(+), 69 deletions(-)

diff --git a/Documentation/cgroup-v1/memcg_test.txt b/Documentation/cgroup-v1/memcg_test.txt
index 8870b0212150..78a8c2963b38 100644
--- a/Documentation/cgroup-v1/memcg_test.txt
+++ b/Documentation/cgroup-v1/memcg_test.txt
@@ -107,9 +107,9 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
 
 8. LRU
         Each memcg has its own private LRU. Now, its handling is under global
-	VM's control (means that it's handled under global zone->lru_lock).
+	VM's control (means that it's handled under global zone_lru_lock).
 	Almost all routines around memcg's LRU is called by global LRU's
-	list management functions under zone->lru_lock().
+	list management functions under zone_lru_lock().
 
 	A special function is mem_cgroup_isolate_pages(). This scans
 	memcg's private LRU and call __isolate_lru_page() to extract a page
diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt
index b14abf217239..946e69103cdd 100644
--- a/Documentation/cgroup-v1/memory.txt
+++ b/Documentation/cgroup-v1/memory.txt
@@ -267,11 +267,11 @@ When oom event notifier is registered, event will be delivered.
    Other lock order is following:
    PG_locked.
    mm->page_table_lock
-       zone->lru_lock
+       zone_lru_lock
 	  lock_page_cgroup.
   In many cases, just lock_page_cgroup() is called.
   per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by
-  zone->lru_lock, it has no lock of its own.
+  zone_lru_lock, it has no lock of its own.
 
 2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM)
 
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index e093e1d3285b..ca2ed9a6c8d8 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -118,7 +118,7 @@ struct page {
 	 */
 	union {
 		struct list_head lru;	/* Pageout list, eg. active_list
-					 * protected by zone->lru_lock !
+					 * protected by zone_lru_lock !
 					 * Can be used as a generic list
 					 * by the page owner.
 					 */
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 078ecb81e209..cfa870107abe 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -93,7 +93,7 @@ struct free_area {
 struct pglist_data;
 
 /*
- * zone->lock and zone->lru_lock are two of the hottest locks in the kernel.
+ * zone->lock and the zone lru_lock are two of the hottest locks in the kernel.
  * So add a wild amount of padding here to ensure that they fall into separate
  * cachelines.  There are very few zone structures in the machine, so space
  * consumption is not a concern here.
@@ -496,7 +496,6 @@ struct zone {
 	/* Write-intensive fields used by page reclaim */
 
 	/* Fields commonly accessed by the page reclaim scanner */
-	spinlock_t		lru_lock;
 	struct lruvec		lruvec;
 
 	/*
@@ -690,6 +689,9 @@ typedef struct pglist_data {
 	/* Number of pages migrated during the rate limiting time interval */
 	unsigned long numabalancing_migrate_nr_pages;
 #endif
+	/* Write-intensive fields used by page reclaim */
+	ZONE_PADDING(_pad1_)
+	spinlock_t		lru_lock;
 
 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 	/*
@@ -721,6 +723,10 @@ typedef struct pglist_data {
 
 #define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
 #define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))
+static inline spinlock_t *zone_lru_lock(struct zone *zone)
+{
+	return &zone->zone_pgdat->lru_lock;
+}
 
 static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
 {
diff --git a/mm/compaction.c b/mm/compaction.c
index 0bd53fb05162..7607efb7bee2 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -752,7 +752,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		 * if contended.
 		 */
 		if (!(low_pfn % SWAP_CLUSTER_MAX)
-		    && compact_unlock_should_abort(&zone->lru_lock, flags,
+		    && compact_unlock_should_abort(zone_lru_lock(zone), flags,
 								&locked, cc))
 			break;
 
@@ -813,7 +813,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 			if (unlikely(__PageMovable(page)) &&
 					!PageIsolated(page)) {
 				if (locked) {
-					spin_unlock_irqrestore(&zone->lru_lock,
+					spin_unlock_irqrestore(zone_lru_lock(zone),
 									flags);
 					locked = false;
 				}
@@ -836,7 +836,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 
 		/* If we already hold the lock, we can skip some rechecking */
 		if (!locked) {
-			locked = compact_trylock_irqsave(&zone->lru_lock,
+			locked = compact_trylock_irqsave(zone_lru_lock(zone),
 								&flags, cc);
 			if (!locked)
 				break;
@@ -899,7 +899,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		 */
 		if (nr_isolated) {
 			if (locked) {
-				spin_unlock_irqrestore(&zone->lru_lock,	flags);
+				spin_unlock_irqrestore(zone_lru_lock(zone), flags);
 				locked = false;
 			}
 			acct_isolated(zone, cc);
@@ -927,7 +927,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		low_pfn = end_pfn;
 
 	if (locked)
-		spin_unlock_irqrestore(&zone->lru_lock, flags);
+		spin_unlock_irqrestore(zone_lru_lock(zone), flags);
 
 	/*
 	 * Update the pageblock-skip information and cached scanner pfn,
diff --git a/mm/filemap.c b/mm/filemap.c
index e90c1543ec2d..7ec50bd6f88c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -95,8 +95,8 @@
  *    ->swap_lock		(try_to_unmap_one)
  *    ->private_lock		(try_to_unmap_one)
  *    ->tree_lock		(try_to_unmap_one)
- *    ->zone.lru_lock		(follow_page->mark_page_accessed)
- *    ->zone.lru_lock		(check_pte_range->isolate_lru_page)
+ *    ->zone_lru_lock(zone)	(follow_page->mark_page_accessed)
+ *    ->zone_lru_lock(zone)	(check_pte_range->isolate_lru_page)
  *    ->private_lock		(page_remove_rmap->set_page_dirty)
  *    ->tree_lock		(page_remove_rmap->set_page_dirty)
  *    bdi.wb->list_lock		(page_remove_rmap->set_page_dirty)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 848c16caf8f8..2f997328ae64 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1860,7 +1860,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 		spin_unlock(&head->mapping->tree_lock);
 	}
 
-	spin_unlock_irqrestore(&page_zone(head)->lru_lock, flags);
+	spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
 
 	unfreeze_page(head);
 
@@ -2046,7 +2046,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 		lru_add_drain();
 
 	/* prevent PageLRU to go away from under us, and freeze lru stats */
-	spin_lock_irqsave(&page_zone(head)->lru_lock, flags);
+	spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags);
 
 	if (mapping) {
 		void **pslot;
@@ -2089,7 +2089,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 		spin_unlock(&pgdata->split_queue_lock);
 fail:		if (mapping)
 			spin_unlock(&mapping->tree_lock);
-		spin_unlock_irqrestore(&page_zone(head)->lru_lock, flags);
+		spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
 		unfreeze_page(head);
 		ret = -EBUSY;
 	}
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 40dfca3ef4bb..9b70f9ca8ddf 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2065,7 +2065,7 @@ static void lock_page_lru(struct page *page, int *isolated)
 {
 	struct zone *zone = page_zone(page);
 
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 	if (PageLRU(page)) {
 		struct lruvec *lruvec;
 
@@ -2089,7 +2089,7 @@ static void unlock_page_lru(struct page *page, int isolated)
 		SetPageLRU(page);
 		add_page_to_lru_list(page, lruvec, page_lru(page));
 	}
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 }
 
 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
@@ -2389,7 +2389,7 @@ void memcg_kmem_uncharge(struct page *page, int order)
 
 /*
  * Because tail pages are not marked as "used", set it. We're under
- * zone->lru_lock and migration entries setup in all page mappings.
+ * zone_lru_lock and migration entries setup in all page mappings.
  */
 void mem_cgroup_split_huge_fixup(struct page *head)
 {
diff --git a/mm/mlock.c b/mm/mlock.c
index ef8dc9f395c4..997f63082ff5 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -188,7 +188,7 @@ unsigned int munlock_vma_page(struct page *page)
 	 * might otherwise copy PageMlocked to part of the tail pages before
 	 * we clear it in the head page. It also stabilizes hpage_nr_pages().
 	 */
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 
 	nr_pages = hpage_nr_pages(page);
 	if (!TestClearPageMlocked(page))
@@ -197,14 +197,14 @@ unsigned int munlock_vma_page(struct page *page)
 	__mod_zone_page_state(zone, NR_MLOCK, -nr_pages);
 
 	if (__munlock_isolate_lru_page(page, true)) {
-		spin_unlock_irq(&zone->lru_lock);
+		spin_unlock_irq(zone_lru_lock(zone));
 		__munlock_isolated_page(page);
 		goto out;
 	}
 	__munlock_isolation_failed(page);
 
 unlock_out:
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 
 out:
 	return nr_pages - 1;
@@ -289,7 +289,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 	pagevec_init(&pvec_putback, 0);
 
 	/* Phase 1: page isolation */
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 	for (i = 0; i < nr; i++) {
 		struct page *page = pvec->pages[i];
 
@@ -315,7 +315,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 	}
 	delta_munlocked = -nr + pagevec_count(&pvec_putback);
 	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 
 	/* Now we can release pins of pages that we are not munlocking */
 	pagevec_release(&pvec_putback);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 34e46c02a406..48b5414009ac 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5947,6 +5947,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
 	init_waitqueue_head(&pgdat->kcompactd_wait);
 #endif
 	pgdat_page_ext_init(pgdat);
+	spin_lock_init(&pgdat->lru_lock);
 
 	for (j = 0; j < MAX_NR_ZONES; j++) {
 		struct zone *zone = pgdat->node_zones + j;
@@ -6001,10 +6002,9 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
 		zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100;
 #endif
 		zone->name = zone_names[j];
+		zone->zone_pgdat = pgdat;
 		spin_lock_init(&zone->lock);
-		spin_lock_init(&zone->lru_lock);
 		zone_seqlock_init(zone);
-		zone->zone_pgdat = pgdat;
 		zone_pcp_init(zone);
 
 		/* For bootup, initialized properly in watermark setup */
diff --git a/mm/page_idle.c b/mm/page_idle.c
index 4ea9c4ef5146..ae11aa914e55 100644
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -41,12 +41,12 @@ static struct page *page_idle_get_page(unsigned long pfn)
 		return NULL;
 
 	zone = page_zone(page);
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 	if (unlikely(!PageLRU(page))) {
 		put_page(page);
 		page = NULL;
 	}
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 	return page;
 }
 
diff --git a/mm/rmap.c b/mm/rmap.c
index 256e585c67ef..573253efb645 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -27,7 +27,7 @@
  *         mapping->i_mmap_rwsem
  *           anon_vma->rwsem
  *             mm->page_table_lock or pte_lock
- *               zone->lru_lock (in mark_page_accessed, isolate_lru_page)
+ *               zone_lru_lock (in mark_page_accessed, isolate_lru_page)
  *               swap_lock (in swap_duplicate, swap_info_get)
  *                 mmlist_lock (in mmput, drain_mmlist and others)
  *                 mapping->private_lock (in __set_page_dirty_buffers)
diff --git a/mm/swap.c b/mm/swap.c
index 616df4ddd870..bf37e5cfae81 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -62,12 +62,12 @@ static void __page_cache_release(struct page *page)
 		struct lruvec *lruvec;
 		unsigned long flags;
 
-		spin_lock_irqsave(&zone->lru_lock, flags);
+		spin_lock_irqsave(zone_lru_lock(zone), flags);
 		lruvec = mem_cgroup_page_lruvec(page, zone);
 		VM_BUG_ON_PAGE(!PageLRU(page), page);
 		__ClearPageLRU(page);
 		del_page_from_lru_list(page, lruvec, page_off_lru(page));
-		spin_unlock_irqrestore(&zone->lru_lock, flags);
+		spin_unlock_irqrestore(zone_lru_lock(zone), flags);
 	}
 	mem_cgroup_uncharge(page);
 }
@@ -189,16 +189,16 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 
 		if (pagezone != zone) {
 			if (zone)
-				spin_unlock_irqrestore(&zone->lru_lock, flags);
+				spin_unlock_irqrestore(zone_lru_lock(zone), flags);
 			zone = pagezone;
-			spin_lock_irqsave(&zone->lru_lock, flags);
+			spin_lock_irqsave(zone_lru_lock(zone), flags);
 		}
 
 		lruvec = mem_cgroup_page_lruvec(page, zone);
 		(*move_fn)(page, lruvec, arg);
 	}
 	if (zone)
-		spin_unlock_irqrestore(&zone->lru_lock, flags);
+		spin_unlock_irqrestore(zone_lru_lock(zone), flags);
 	release_pages(pvec->pages, pvec->nr, pvec->cold);
 	pagevec_reinit(pvec);
 }
@@ -318,9 +318,9 @@ void activate_page(struct page *page)
 	struct zone *zone = page_zone(page);
 
 	page = compound_head(page);
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 	__activate_page(page, mem_cgroup_page_lruvec(page, zone), NULL);
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 }
 #endif
 
@@ -448,13 +448,13 @@ void add_page_to_unevictable_list(struct page *page)
 	struct zone *zone = page_zone(page);
 	struct lruvec *lruvec;
 
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 	lruvec = mem_cgroup_page_lruvec(page, zone);
 	ClearPageActive(page);
 	SetPageUnevictable(page);
 	SetPageLRU(page);
 	add_page_to_lru_list(page, lruvec, LRU_UNEVICTABLE);
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 }
 
 /**
@@ -744,7 +744,7 @@ void release_pages(struct page **pages, int nr, bool cold)
 		 * same zone. The lock is held only if zone != NULL.
 		 */
 		if (zone && ++lock_batch == SWAP_CLUSTER_MAX) {
-			spin_unlock_irqrestore(&zone->lru_lock, flags);
+			spin_unlock_irqrestore(zone_lru_lock(zone), flags);
 			zone = NULL;
 		}
 
@@ -759,7 +759,7 @@ void release_pages(struct page **pages, int nr, bool cold)
 
 		if (PageCompound(page)) {
 			if (zone) {
-				spin_unlock_irqrestore(&zone->lru_lock, flags);
+				spin_unlock_irqrestore(zone_lru_lock(zone), flags);
 				zone = NULL;
 			}
 			__put_compound_page(page);
@@ -771,11 +771,11 @@ void release_pages(struct page **pages, int nr, bool cold)
 
 			if (pagezone != zone) {
 				if (zone)
-					spin_unlock_irqrestore(&zone->lru_lock,
+					spin_unlock_irqrestore(zone_lru_lock(zone),
 									flags);
 				lock_batch = 0;
 				zone = pagezone;
-				spin_lock_irqsave(&zone->lru_lock, flags);
+				spin_lock_irqsave(zone_lru_lock(zone), flags);
 			}
 
 			lruvec = mem_cgroup_page_lruvec(page, zone);
@@ -790,7 +790,7 @@ void release_pages(struct page **pages, int nr, bool cold)
 		list_add(&page->lru, &pages_to_free);
 	}
 	if (zone)
-		spin_unlock_irqrestore(&zone->lru_lock, flags);
+		spin_unlock_irqrestore(zone_lru_lock(zone), flags);
 
 	mem_cgroup_uncharge_list(&pages_to_free);
 	free_hot_cold_page_list(&pages_to_free, cold);
@@ -826,7 +826,7 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
 	VM_BUG_ON_PAGE(PageCompound(page_tail), page);
 	VM_BUG_ON_PAGE(PageLRU(page_tail), page);
 	VM_BUG_ON(NR_CPUS != 1 &&
-		  !spin_is_locked(&lruvec_zone(lruvec)->lru_lock));
+		  !spin_is_locked(zone_lru_lock(lruvec_zone(lruvec))));
 
 	if (!list)
 		SetPageLRU(page_tail);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 21d417ccff69..e7ffcd259cc4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1349,7 +1349,7 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode)
 }
 
 /*
- * zone->lru_lock is heavily contended.  Some of the functions that
+ * zone_lru_lock is heavily contended.  Some of the functions that
  * shrink the lists perform better by taking out a batch of pages
  * and working on them outside the LRU lock.
  *
@@ -1444,7 +1444,7 @@ int isolate_lru_page(struct page *page)
 		struct zone *zone = page_zone(page);
 		struct lruvec *lruvec;
 
-		spin_lock_irq(&zone->lru_lock);
+		spin_lock_irq(zone_lru_lock(zone));
 		lruvec = mem_cgroup_page_lruvec(page, zone);
 		if (PageLRU(page)) {
 			int lru = page_lru(page);
@@ -1453,7 +1453,7 @@ int isolate_lru_page(struct page *page)
 			del_page_from_lru_list(page, lruvec, lru);
 			ret = 0;
 		}
-		spin_unlock_irq(&zone->lru_lock);
+		spin_unlock_irq(zone_lru_lock(zone));
 	}
 	return ret;
 }
@@ -1512,9 +1512,9 @@ putback_inactive_pages(struct lruvec *lruvec, struct list_head *page_list)
 		VM_BUG_ON_PAGE(PageLRU(page), page);
 		list_del(&page->lru);
 		if (unlikely(!page_evictable(page))) {
-			spin_unlock_irq(&zone->lru_lock);
+			spin_unlock_irq(zone_lru_lock(zone));
 			putback_lru_page(page);
-			spin_lock_irq(&zone->lru_lock);
+			spin_lock_irq(zone_lru_lock(zone));
 			continue;
 		}
 
@@ -1535,10 +1535,10 @@ putback_inactive_pages(struct lruvec *lruvec, struct list_head *page_list)
 			del_page_from_lru_list(page, lruvec, lru);
 
 			if (unlikely(PageCompound(page))) {
-				spin_unlock_irq(&zone->lru_lock);
+				spin_unlock_irq(zone_lru_lock(zone));
 				mem_cgroup_uncharge(page);
 				(*get_compound_page_dtor(page))(page);
-				spin_lock_irq(&zone->lru_lock);
+				spin_lock_irq(zone_lru_lock(zone));
 			} else
 				list_add(&page->lru, &pages_to_free);
 		}
@@ -1600,7 +1600,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 	if (!sc->may_writepage)
 		isolate_mode |= ISOLATE_CLEAN;
 
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 
 	nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &page_list,
 				     &nr_scanned, sc, isolate_mode, lru);
@@ -1616,7 +1616,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 		else
 			__count_zone_vm_events(PGSCAN_DIRECT, zone, nr_scanned);
 	}
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 
 	if (nr_taken == 0)
 		return 0;
@@ -1626,7 +1626,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 				&nr_writeback, &nr_immediate,
 				false);
 
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 
 	if (global_reclaim(sc)) {
 		if (current_is_kswapd())
@@ -1641,7 +1641,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 
 	__mod_zone_page_state(zone, NR_ISOLATED_ANON + file, -nr_taken);
 
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 
 	mem_cgroup_uncharge_list(&page_list);
 	free_hot_cold_page_list(&page_list, true);
@@ -1715,9 +1715,9 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
  * processes, from rmap.
  *
  * If the pages are mostly unmapped, the processing is fast and it is
- * appropriate to hold zone->lru_lock across the whole operation.  But if
+ * appropriate to hold zone_lru_lock across the whole operation.  But if
  * the pages are mapped, the processing is slow (page_referenced()) so we
- * should drop zone->lru_lock around each page.  It's impossible to balance
+ * should drop zone_lru_lock around each page.  It's impossible to balance
  * this, so instead we remove the pages from the LRU while processing them.
  * It is safe to rely on PG_active against the non-LRU pages in here because
  * nobody will play with that bit on a non-LRU page.
@@ -1754,10 +1754,10 @@ static void move_active_pages_to_lru(struct lruvec *lruvec,
 			del_page_from_lru_list(page, lruvec, lru);
 
 			if (unlikely(PageCompound(page))) {
-				spin_unlock_irq(&zone->lru_lock);
+				spin_unlock_irq(zone_lru_lock(zone));
 				mem_cgroup_uncharge(page);
 				(*get_compound_page_dtor(page))(page);
-				spin_lock_irq(&zone->lru_lock);
+				spin_lock_irq(zone_lru_lock(zone));
 			} else
 				list_add(&page->lru, pages_to_free);
 		}
@@ -1792,7 +1792,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	if (!sc->may_writepage)
 		isolate_mode |= ISOLATE_CLEAN;
 
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 
 	nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &l_hold,
 				     &nr_scanned, sc, isolate_mode, lru);
@@ -1805,7 +1805,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 		__mod_zone_page_state(zone, NR_PAGES_SCANNED, nr_scanned);
 	__count_zone_vm_events(PGREFILL, zone, nr_scanned);
 
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 
 	while (!list_empty(&l_hold)) {
 		cond_resched();
@@ -1850,7 +1850,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	/*
 	 * Move pages back to the lru list.
 	 */
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 	/*
 	 * Count referenced pages from currently used mappings as rotated,
 	 * even though only some of them are actually re-activated.  This
@@ -1862,7 +1862,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	move_active_pages_to_lru(lruvec, &l_active, &l_hold, lru);
 	move_active_pages_to_lru(lruvec, &l_inactive, &l_hold, lru - LRU_ACTIVE);
 	__mod_zone_page_state(zone, NR_ISOLATED_ANON + file, -nr_taken);
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 
 	mem_cgroup_uncharge_list(&l_hold);
 	free_hot_cold_page_list(&l_hold, true);
@@ -2077,7 +2077,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
 	file  = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE) +
 		lruvec_lru_size(lruvec, LRU_INACTIVE_FILE);
 
-	spin_lock_irq(&zone->lru_lock);
+	spin_lock_irq(zone_lru_lock(zone));
 	if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
 		reclaim_stat->recent_scanned[0] /= 2;
 		reclaim_stat->recent_rotated[0] /= 2;
@@ -2098,7 +2098,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
 
 	fp = file_prio * (reclaim_stat->recent_scanned[1] + 1);
 	fp /= reclaim_stat->recent_rotated[1] + 1;
-	spin_unlock_irq(&zone->lru_lock);
+	spin_unlock_irq(zone_lru_lock(zone));
 
 	fraction[0] = ap;
 	fraction[1] = fp;
@@ -3791,9 +3791,9 @@ void check_move_unevictable_pages(struct page **pages, int nr_pages)
 		pagezone = page_zone(page);
 		if (pagezone != zone) {
 			if (zone)
-				spin_unlock_irq(&zone->lru_lock);
+				spin_unlock_irq(zone_lru_lock(zone));
 			zone = pagezone;
-			spin_lock_irq(&zone->lru_lock);
+			spin_lock_irq(zone_lru_lock(zone));
 		}
 		lruvec = mem_cgroup_page_lruvec(page, zone);
 
@@ -3814,7 +3814,7 @@ void check_move_unevictable_pages(struct page **pages, int nr_pages)
 	if (zone) {
 		__count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued);
 		__count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned);
-		spin_unlock_irq(&zone->lru_lock);
+		spin_unlock_irq(zone_lru_lock(zone));
 	}
 }
 #endif /* CONFIG_SHMEM */
-- 
2.6.4

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#1439238 — [PATCH 15/34] mm, workingset: make working set detection node-aware

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 15/34] mm, workingset: make working set detection node-aware
Message-ID<rSAqm-2Tv-35@gated-at.bofh.it>
In reply to#1439225
Working set and refault detection is still zone-based, fix it.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/mmzone.h |  6 +++---
 include/linux/vmstat.h |  1 -
 mm/vmstat.c            | 20 +++-----------------
 mm/workingset.c        | 43 ++++++++++++++++++++-----------------------
 4 files changed, 26 insertions(+), 44 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 895c365e3259..62f477d6cfe8 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -145,9 +145,6 @@ enum zone_stat_item {
 	NUMA_LOCAL,		/* allocation from local node */
 	NUMA_OTHER,		/* allocation from other node */
 #endif
-	WORKINGSET_REFAULT,
-	WORKINGSET_ACTIVATE,
-	WORKINGSET_NODERECLAIM,
 	NR_ANON_THPS,
 	NR_SHMEM_THPS,
 	NR_SHMEM_PMDMAPPED,
@@ -164,6 +161,9 @@ enum node_stat_item {
 	NR_ISOLATED_ANON,	/* Temporary isolated pages from anon lru */
 	NR_ISOLATED_FILE,	/* Temporary isolated pages from file lru */
 	NR_PAGES_SCANNED,	/* pages scanned since last reclaim */
+	WORKINGSET_REFAULT,
+	WORKINGSET_ACTIVATE,
+	WORKINGSET_NODERECLAIM,
 	NR_VM_NODE_STAT_ITEMS
 };
 
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index fee321c98550..6b7975cd98aa 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -227,7 +227,6 @@ void mod_node_page_state(struct pglist_data *, enum node_stat_item, long);
 void inc_node_page_state(struct page *, enum node_stat_item);
 void dec_node_page_state(struct page *, enum node_stat_item);
 
-extern void inc_zone_state(struct zone *, enum zone_stat_item);
 extern void inc_node_state(struct pglist_data *, enum node_stat_item);
 extern void __inc_zone_state(struct zone *, enum zone_stat_item);
 extern void __inc_node_state(struct pglist_data *, enum node_stat_item);
diff --git a/mm/vmstat.c b/mm/vmstat.c
index de0c17076270..d17d66e85def 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -446,11 +446,6 @@ void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 }
 EXPORT_SYMBOL(mod_zone_page_state);
 
-void inc_zone_state(struct zone *zone, enum zone_stat_item item)
-{
-	mod_zone_state(zone, item, 1, 1);
-}
-
 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 {
 	mod_zone_state(page_zone(page), item, 1, 1);
@@ -539,15 +534,6 @@ void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 }
 EXPORT_SYMBOL(mod_zone_page_state);
 
-void inc_zone_state(struct zone *zone, enum zone_stat_item item)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	__inc_zone_state(zone, item);
-	local_irq_restore(flags);
-}
-
 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 {
 	unsigned long flags;
@@ -967,9 +953,6 @@ const char * const vmstat_text[] = {
 	"numa_local",
 	"numa_other",
 #endif
-	"workingset_refault",
-	"workingset_activate",
-	"workingset_nodereclaim",
 	"nr_anon_transparent_hugepages",
 	"nr_shmem_hugepages",
 	"nr_shmem_pmdmapped",
@@ -984,6 +967,9 @@ const char * const vmstat_text[] = {
 	"nr_isolated_anon",
 	"nr_isolated_file",
 	"nr_pages_scanned",
+	"workingset_refault",
+	"workingset_activate",
+	"workingset_nodereclaim",
 
 	/* enum writeback_stat_item counters */
 	"nr_dirty_threshold",
diff --git a/mm/workingset.c b/mm/workingset.c
index 9a1016f5d500..56334e7d6924 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -16,7 +16,7 @@
 /*
  *		Double CLOCK lists
  *
- * Per zone, two clock lists are maintained for file pages: the
+ * Per node, two clock lists are maintained for file pages: the
  * inactive and the active list.  Freshly faulted pages start out at
  * the head of the inactive list and page reclaim scans pages from the
  * tail.  Pages that are accessed multiple times on the inactive list
@@ -141,11 +141,11 @@
  *
  *		Implementation
  *
- * For each zone's file LRU lists, a counter for inactive evictions
- * and activations is maintained (zone->inactive_age).
+ * For each node's file LRU lists, a counter for inactive evictions
+ * and activations is maintained (node->inactive_age).
  *
  * On eviction, a snapshot of this counter (along with some bits to
- * identify the zone) is stored in the now empty page cache radix tree
+ * identify the node) is stored in the now empty page cache radix tree
  * slot of the evicted page.  This is called a shadow entry.
  *
  * On cache misses for which there are shadow entries, an eligible
@@ -153,7 +153,7 @@
  */
 
 #define EVICTION_SHIFT	(RADIX_TREE_EXCEPTIONAL_ENTRY + \
-			 ZONES_SHIFT + NODES_SHIFT +	\
+			 NODES_SHIFT +	\
 			 MEM_CGROUP_ID_SHIFT)
 #define EVICTION_MASK	(~0UL >> EVICTION_SHIFT)
 
@@ -167,33 +167,30 @@
  */
 static unsigned int bucket_order __read_mostly;
 
-static void *pack_shadow(int memcgid, struct zone *zone, unsigned long eviction)
+static void *pack_shadow(int memcgid, pg_data_t *pgdat, unsigned long eviction)
 {
 	eviction >>= bucket_order;
 	eviction = (eviction << MEM_CGROUP_ID_SHIFT) | memcgid;
-	eviction = (eviction << NODES_SHIFT) | zone_to_nid(zone);
-	eviction = (eviction << ZONES_SHIFT) | zone_idx(zone);
+	eviction = (eviction << NODES_SHIFT) | pgdat->node_id;
 	eviction = (eviction << RADIX_TREE_EXCEPTIONAL_SHIFT);
 
 	return (void *)(eviction | RADIX_TREE_EXCEPTIONAL_ENTRY);
 }
 
-static void unpack_shadow(void *shadow, int *memcgidp, struct zone **zonep,
+static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat,
 			  unsigned long *evictionp)
 {
 	unsigned long entry = (unsigned long)shadow;
-	int memcgid, nid, zid;
+	int memcgid, nid;
 
 	entry >>= RADIX_TREE_EXCEPTIONAL_SHIFT;
-	zid = entry & ((1UL << ZONES_SHIFT) - 1);
-	entry >>= ZONES_SHIFT;
 	nid = entry & ((1UL << NODES_SHIFT) - 1);
 	entry >>= NODES_SHIFT;
 	memcgid = entry & ((1UL << MEM_CGROUP_ID_SHIFT) - 1);
 	entry >>= MEM_CGROUP_ID_SHIFT;
 
 	*memcgidp = memcgid;
-	*zonep = NODE_DATA(nid)->node_zones + zid;
+	*pgdat = NODE_DATA(nid);
 	*evictionp = entry << bucket_order;
 }
 
@@ -208,7 +205,7 @@ static void unpack_shadow(void *shadow, int *memcgidp, struct zone **zonep,
 void *workingset_eviction(struct address_space *mapping, struct page *page)
 {
 	struct mem_cgroup *memcg = page_memcg(page);
-	struct zone *zone = page_zone(page);
+	struct pglist_data *pgdat = page_pgdat(page);
 	int memcgid = mem_cgroup_id(memcg);
 	unsigned long eviction;
 	struct lruvec *lruvec;
@@ -218,9 +215,9 @@ void *workingset_eviction(struct address_space *mapping, struct page *page)
 	VM_BUG_ON_PAGE(page_count(page), page);
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 
-	lruvec = mem_cgroup_lruvec(zone->zone_pgdat, memcg);
+	lruvec = mem_cgroup_lruvec(pgdat, memcg);
 	eviction = atomic_long_inc_return(&lruvec->inactive_age);
-	return pack_shadow(memcgid, zone, eviction);
+	return pack_shadow(memcgid, pgdat, eviction);
 }
 
 /**
@@ -228,7 +225,7 @@ void *workingset_eviction(struct address_space *mapping, struct page *page)
  * @shadow: shadow entry of the evicted page
  *
  * Calculates and evaluates the refault distance of the previously
- * evicted page in the context of the zone it was allocated in.
+ * evicted page in the context of the node it was allocated in.
  *
  * Returns %true if the page should be activated, %false otherwise.
  */
@@ -240,10 +237,10 @@ bool workingset_refault(void *shadow)
 	unsigned long eviction;
 	struct lruvec *lruvec;
 	unsigned long refault;
-	struct zone *zone;
+	struct pglist_data *pgdat;
 	int memcgid;
 
-	unpack_shadow(shadow, &memcgid, &zone, &eviction);
+	unpack_shadow(shadow, &memcgid, &pgdat, &eviction);
 
 	rcu_read_lock();
 	/*
@@ -267,7 +264,7 @@ bool workingset_refault(void *shadow)
 		rcu_read_unlock();
 		return false;
 	}
-	lruvec = mem_cgroup_lruvec(zone->zone_pgdat, memcg);
+	lruvec = mem_cgroup_lruvec(pgdat, memcg);
 	refault = atomic_long_read(&lruvec->inactive_age);
 	active_file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE);
 	rcu_read_unlock();
@@ -290,10 +287,10 @@ bool workingset_refault(void *shadow)
 	 */
 	refault_distance = (refault - eviction) & EVICTION_MASK;
 
-	inc_zone_state(zone, WORKINGSET_REFAULT);
+	inc_node_state(pgdat, WORKINGSET_REFAULT);
 
 	if (refault_distance <= active_file) {
-		inc_zone_state(zone, WORKINGSET_ACTIVATE);
+		inc_node_state(pgdat, WORKINGSET_ACTIVATE);
 		return true;
 	}
 	return false;
@@ -436,7 +433,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 		}
 	}
 	BUG_ON(node->count);
-	inc_zone_state(page_zone(virt_to_page(node)), WORKINGSET_NODERECLAIM);
+	inc_node_state(page_pgdat(virt_to_page(node)), WORKINGSET_NODERECLAIM);
 	if (!__radix_tree_delete_node(&mapping->page_tree, node))
 		BUG();
 
-- 
2.6.4

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#1439239 — [PATCH 23/34] mm: convert zone_reclaim to node_reclaim

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:40 +0200
Subject[PATCH 23/34] mm: convert zone_reclaim to node_reclaim
Message-ID<rSAqm-2Tv-37@gated-at.bofh.it>
In reply to#1439225
As reclaim is now per-node based, convert zone_reclaim to be node_reclaim.
It is possible that a node will be reclaimed multiple times if it has
multiple zones but this is unavoidable without caching all nodes traversed
so far.  The documentation and interface to userspace is the same from a
configuration perspective and will will be similar in behaviour unless the
node-local allocation requests were also limited to lower zones.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/mmzone.h   | 18 +++++------
 include/linux/swap.h     |  9 +++---
 include/linux/topology.h |  2 +-
 kernel/sysctl.c          |  4 +--
 mm/internal.h            |  8 ++---
 mm/khugepaged.c          |  4 +--
 mm/page_alloc.c          | 24 ++++++++++-----
 mm/vmscan.c              | 77 ++++++++++++++++++++++++------------------------
 8 files changed, 77 insertions(+), 69 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index e3d6d42722a0..e19c081c794e 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -372,14 +372,6 @@ struct zone {
 	unsigned long		*pageblock_flags;
 #endif /* CONFIG_SPARSEMEM */
 
-#ifdef CONFIG_NUMA
-	/*
-	 * zone reclaim becomes active if more unmapped pages exist.
-	 */
-	unsigned long		min_unmapped_pages;
-	unsigned long		min_slab_pages;
-#endif /* CONFIG_NUMA */
-
 	/* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
 	unsigned long		zone_start_pfn;
 
@@ -525,7 +517,6 @@ struct zone {
 } ____cacheline_internodealigned_in_smp;
 
 enum zone_flags {
-	ZONE_RECLAIM_LOCKED,		/* prevents concurrent reclaim */
 	ZONE_FAIR_DEPLETED,		/* fair zone policy batch depleted */
 };
 
@@ -540,6 +531,7 @@ enum pgdat_flags {
 	PGDAT_WRITEBACK,		/* reclaim scanning has recently found
 					 * many pages under writeback
 					 */
+	PGDAT_RECLAIM_LOCKED,		/* prevents concurrent reclaim */
 };
 
 static inline unsigned long zone_end_pfn(const struct zone *zone)
@@ -688,6 +680,14 @@ typedef struct pglist_data {
 	 */
 	unsigned long		totalreserve_pages;
 
+#ifdef CONFIG_NUMA
+	/*
+	 * zone reclaim becomes active if more unmapped pages exist.
+	 */
+	unsigned long		min_unmapped_pages;
+	unsigned long		min_slab_pages;
+#endif /* CONFIG_NUMA */
+
 	/* Write-intensive fields used by page reclaim */
 	ZONE_PADDING(_pad1_)
 	spinlock_t		lru_lock;
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 2a23ddc96edd..b17cc4830fa6 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -326,13 +326,14 @@ extern int remove_mapping(struct address_space *mapping, struct page *page);
 extern unsigned long vm_total_pages;
 
 #ifdef CONFIG_NUMA
-extern int zone_reclaim_mode;
+extern int node_reclaim_mode;
 extern int sysctl_min_unmapped_ratio;
 extern int sysctl_min_slab_ratio;
-extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
+extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
 #else
-#define zone_reclaim_mode 0
-static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
+#define node_reclaim_mode 0
+static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask,
+				unsigned int order)
 {
 	return 0;
 }
diff --git a/include/linux/topology.h b/include/linux/topology.h
index afce69296ac0..cb0775e1ee4b 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -54,7 +54,7 @@ int arch_update_cpu_topology(void);
 /*
  * If the distance between nodes in a system is larger than RECLAIM_DISTANCE
  * (in whatever arch specific measurement units returned by node_distance())
- * and zone_reclaim_mode is enabled then the VM will only call zone_reclaim()
+ * and node_reclaim_mode is enabled then the VM will only call node_reclaim()
  * on nodes within this distance.
  */
 #define RECLAIM_DISTANCE 30
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index de331c3858e5..6e47ebe5384e 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1498,8 +1498,8 @@ static struct ctl_table vm_table[] = {
 #ifdef CONFIG_NUMA
 	{
 		.procname	= "zone_reclaim_mode",
-		.data		= &zone_reclaim_mode,
-		.maxlen		= sizeof(zone_reclaim_mode),
+		.data		= &node_reclaim_mode,
+		.maxlen		= sizeof(node_reclaim_mode),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &zero,
diff --git a/mm/internal.h b/mm/internal.h
index 2f80d0343c56..1e21b2d3838d 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -433,10 +433,10 @@ static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 }
 #endif /* CONFIG_SPARSEMEM */
 
-#define ZONE_RECLAIM_NOSCAN	-2
-#define ZONE_RECLAIM_FULL	-1
-#define ZONE_RECLAIM_SOME	0
-#define ZONE_RECLAIM_SUCCESS	1
+#define NODE_RECLAIM_NOSCAN	-2
+#define NODE_RECLAIM_FULL	-1
+#define NODE_RECLAIM_SOME	0
+#define NODE_RECLAIM_SUCCESS	1
 
 extern int hwpoison_filter(struct page *p);
 
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index d907cdc3dc28..bb49bd1d2d9f 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -672,10 +672,10 @@ static bool khugepaged_scan_abort(int nid)
 	int i;
 
 	/*
-	 * If zone_reclaim_mode is disabled, then no extra effort is made to
+	 * If node_reclaim_mode is disabled, then no extra effort is made to
 	 * allocate memory locally.
 	 */
-	if (!zone_reclaim_mode)
+	if (!node_reclaim_mode)
 		return false;
 
 	/* If there is a count for this node already, it must be acceptable */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e6ee52f1c15f..de825b07e233 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2985,16 +2985,16 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
 			if (alloc_flags & ALLOC_NO_WATERMARKS)
 				goto try_this_zone;
 
-			if (zone_reclaim_mode == 0 ||
+			if (node_reclaim_mode == 0 ||
 			    !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
 				continue;
 
-			ret = zone_reclaim(zone, gfp_mask, order);
+			ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
 			switch (ret) {
-			case ZONE_RECLAIM_NOSCAN:
+			case NODE_RECLAIM_NOSCAN:
 				/* did not scan */
 				continue;
-			case ZONE_RECLAIM_FULL:
+			case NODE_RECLAIM_FULL:
 				/* scanned but unreclaimable */
 				continue;
 			default:
@@ -5991,9 +5991,9 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
 		zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
 #ifdef CONFIG_NUMA
 		zone->node = nid;
-		zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio)
+		pgdat->min_unmapped_pages += (freesize*sysctl_min_unmapped_ratio)
 						/ 100;
-		zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100;
+		pgdat->min_slab_pages += (freesize * sysctl_min_slab_ratio) / 100;
 #endif
 		zone->name = zone_names[j];
 		zone->zone_pgdat = pgdat;
@@ -6970,6 +6970,7 @@ int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
 	void __user *buffer, size_t *length, loff_t *ppos)
 {
+	struct pglist_data *pgdat;
 	struct zone *zone;
 	int rc;
 
@@ -6977,8 +6978,11 @@ int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
 	if (rc)
 		return rc;
 
+	for_each_online_pgdat(pgdat)
+		pgdat->min_slab_pages = 0;
+
 	for_each_zone(zone)
-		zone->min_unmapped_pages = (zone->managed_pages *
+		zone->zone_pgdat->min_unmapped_pages += (zone->managed_pages *
 				sysctl_min_unmapped_ratio) / 100;
 	return 0;
 }
@@ -6986,6 +6990,7 @@ int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
 	void __user *buffer, size_t *length, loff_t *ppos)
 {
+	struct pglist_data *pgdat;
 	struct zone *zone;
 	int rc;
 
@@ -6993,8 +6998,11 @@ int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
 	if (rc)
 		return rc;
 
+	for_each_online_pgdat(pgdat)
+		pgdat->min_slab_pages = 0;
+
 	for_each_zone(zone)
-		zone->min_slab_pages = (zone->managed_pages *
+		zone->zone_pgdat->min_slab_pages += (zone->managed_pages *
 				sysctl_min_slab_ratio) / 100;
 	return 0;
 }
diff --git a/mm/vmscan.c b/mm/vmscan.c
index cc820bbe9c01..e12b0fd2044c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3563,12 +3563,12 @@ module_init(kswapd_init)
 
 #ifdef CONFIG_NUMA
 /*
- * Zone reclaim mode
+ * Node reclaim mode
  *
- * If non-zero call zone_reclaim when the number of free pages falls below
+ * If non-zero call node_reclaim when the number of free pages falls below
  * the watermarks.
  */
-int zone_reclaim_mode __read_mostly;
+int node_reclaim_mode __read_mostly;
 
 #define RECLAIM_OFF 0
 #define RECLAIM_ZONE (1<<0)	/* Run shrink_inactive_list on the zone */
@@ -3576,14 +3576,14 @@ int zone_reclaim_mode __read_mostly;
 #define RECLAIM_UNMAP (1<<2)	/* Unmap pages during reclaim */
 
 /*
- * Priority for ZONE_RECLAIM. This determines the fraction of pages
+ * Priority for NODE_RECLAIM. This determines the fraction of pages
  * of a node considered for each zone_reclaim. 4 scans 1/16th of
  * a zone.
  */
-#define ZONE_RECLAIM_PRIORITY 4
+#define NODE_RECLAIM_PRIORITY 4
 
 /*
- * Percentage of pages in a zone that must be unmapped for zone_reclaim to
+ * Percentage of pages in a zone that must be unmapped for node_reclaim to
  * occur.
  */
 int sysctl_min_unmapped_ratio = 1;
@@ -3609,7 +3609,7 @@ static inline unsigned long node_unmapped_file_pages(struct pglist_data *pgdat)
 }
 
 /* Work out how many page cache pages we can reclaim in this reclaim_mode */
-static unsigned long zone_pagecache_reclaimable(struct zone *zone)
+static unsigned long node_pagecache_reclaimable(struct pglist_data *pgdat)
 {
 	unsigned long nr_pagecache_reclaimable;
 	unsigned long delta = 0;
@@ -3620,14 +3620,14 @@ static unsigned long zone_pagecache_reclaimable(struct zone *zone)
 	 * pages like swapcache and node_unmapped_file_pages() provides
 	 * a better estimate
 	 */
-	if (zone_reclaim_mode & RECLAIM_UNMAP)
-		nr_pagecache_reclaimable = node_page_state(zone->zone_pgdat, NR_FILE_PAGES);
+	if (node_reclaim_mode & RECLAIM_UNMAP)
+		nr_pagecache_reclaimable = node_page_state(pgdat, NR_FILE_PAGES);
 	else
-		nr_pagecache_reclaimable = node_unmapped_file_pages(zone->zone_pgdat);
+		nr_pagecache_reclaimable = node_unmapped_file_pages(pgdat);
 
 	/* If we can't clean pages, remove dirty pages from consideration */
-	if (!(zone_reclaim_mode & RECLAIM_WRITE))
-		delta += node_page_state(zone->zone_pgdat, NR_FILE_DIRTY);
+	if (!(node_reclaim_mode & RECLAIM_WRITE))
+		delta += node_page_state(pgdat, NR_FILE_DIRTY);
 
 	/* Watch for any possible underflows due to delta */
 	if (unlikely(delta > nr_pagecache_reclaimable))
@@ -3637,23 +3637,24 @@ static unsigned long zone_pagecache_reclaimable(struct zone *zone)
 }
 
 /*
- * Try to free up some pages from this zone through reclaim.
+ * Try to free up some pages from this node through reclaim.
  */
-static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
+static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order)
 {
 	/* Minimum pages needed in order to stay on node */
 	const unsigned long nr_pages = 1 << order;
 	struct task_struct *p = current;
 	struct reclaim_state reclaim_state;
+	int classzone_idx = gfp_zone(gfp_mask);
 	struct scan_control sc = {
 		.nr_to_reclaim = max(nr_pages, SWAP_CLUSTER_MAX),
 		.gfp_mask = (gfp_mask = memalloc_noio_flags(gfp_mask)),
 		.order = order,
-		.priority = ZONE_RECLAIM_PRIORITY,
-		.may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE),
-		.may_unmap = !!(zone_reclaim_mode & RECLAIM_UNMAP),
+		.priority = NODE_RECLAIM_PRIORITY,
+		.may_writepage = !!(node_reclaim_mode & RECLAIM_WRITE),
+		.may_unmap = !!(node_reclaim_mode & RECLAIM_UNMAP),
 		.may_swap = 1,
-		.reclaim_idx = zone_idx(zone),
+		.reclaim_idx = classzone_idx,
 	};
 
 	cond_resched();
@@ -3667,13 +3668,13 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 	reclaim_state.reclaimed_slab = 0;
 	p->reclaim_state = &reclaim_state;
 
-	if (zone_pagecache_reclaimable(zone) > zone->min_unmapped_pages) {
+	if (node_pagecache_reclaimable(pgdat) > pgdat->min_unmapped_pages) {
 		/*
 		 * Free memory by calling shrink zone with increasing
 		 * priorities until we have enough memory freed.
 		 */
 		do {
-			shrink_node(zone->zone_pgdat, &sc, zone_idx(zone));
+			shrink_node(pgdat, &sc, classzone_idx);
 		} while (sc.nr_reclaimed < nr_pages && --sc.priority >= 0);
 	}
 
@@ -3683,49 +3684,47 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 	return sc.nr_reclaimed >= nr_pages;
 }
 
-int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
+int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order)
 {
-	int node_id;
 	int ret;
 
 	/*
-	 * Zone reclaim reclaims unmapped file backed pages and
+	 * Node reclaim reclaims unmapped file backed pages and
 	 * slab pages if we are over the defined limits.
 	 *
 	 * A small portion of unmapped file backed pages is needed for
 	 * file I/O otherwise pages read by file I/O will be immediately
-	 * thrown out if the zone is overallocated. So we do not reclaim
-	 * if less than a specified percentage of the zone is used by
+	 * thrown out if the node is overallocated. So we do not reclaim
+	 * if less than a specified percentage of the node is used by
 	 * unmapped file backed pages.
 	 */
-	if (zone_pagecache_reclaimable(zone) <= zone->min_unmapped_pages &&
-	    zone_page_state(zone, NR_SLAB_RECLAIMABLE) <= zone->min_slab_pages)
-		return ZONE_RECLAIM_FULL;
+	if (node_pagecache_reclaimable(pgdat) <= pgdat->min_unmapped_pages &&
+	    sum_zone_node_page_state(pgdat->node_id, NR_SLAB_RECLAIMABLE) <= pgdat->min_slab_pages)
+		return NODE_RECLAIM_FULL;
 
-	if (!pgdat_reclaimable(zone->zone_pgdat))
-		return ZONE_RECLAIM_FULL;
+	if (!pgdat_reclaimable(pgdat))
+		return NODE_RECLAIM_FULL;
 
 	/*
 	 * Do not scan if the allocation should not be delayed.
 	 */
 	if (!gfpflags_allow_blocking(gfp_mask) || (current->flags & PF_MEMALLOC))
-		return ZONE_RECLAIM_NOSCAN;
+		return NODE_RECLAIM_NOSCAN;
 
 	/*
-	 * Only run zone reclaim on the local zone or on zones that do not
+	 * Only run node reclaim on the local node or on nodes that do not
 	 * have associated processors. This will favor the local processor
 	 * over remote processors and spread off node memory allocations
 	 * as wide as possible.
 	 */
-	node_id = zone_to_nid(zone);
-	if (node_state(node_id, N_CPU) && node_id != numa_node_id())
-		return ZONE_RECLAIM_NOSCAN;
+	if (node_state(pgdat->node_id, N_CPU) && pgdat->node_id != numa_node_id())
+		return NODE_RECLAIM_NOSCAN;
 
-	if (test_and_set_bit(ZONE_RECLAIM_LOCKED, &zone->flags))
-		return ZONE_RECLAIM_NOSCAN;
+	if (test_and_set_bit(PGDAT_RECLAIM_LOCKED, &pgdat->flags))
+		return NODE_RECLAIM_NOSCAN;
 
-	ret = __zone_reclaim(zone, gfp_mask, order);
-	clear_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
+	ret = __node_reclaim(pgdat, gfp_mask, order);
+	clear_bit(PGDAT_RECLAIM_LOCKED, &pgdat->flags);
 
 	if (!ret)
 		count_vm_event(PGSCAN_ZONE_RECLAIM_FAILED);
-- 
2.6.4

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#1439240 — [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:50 +0200
Subject[PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes
Message-ID<rSAA1-2Xn-1@gated-at.bofh.it>
In reply to#1439225
Patch "mm: vmscan: Begin reclaiming pages on a per-node basis" started
thinking of reclaim in terms of nodes but kswapd is still zone-centric. This
patch gets rid of many of the node-based versus zone-based decisions.

o A node is considered balanced when any eligible lower zone is balanced.
  This eliminates one class of age-inversion problem because we avoid
  reclaiming a newer page just because it's in the wrong zone
o pgdat_balanced disappears because we now only care about one zone being
  balanced.
o Some anomalies related to writeback and congestion tracking being based on
  zones disappear.
o kswapd no longer has to take care to reclaim zones in the reverse order
  that the page allocator uses.
o Most importantly of all, reclaim from node 0 with multiple zones will
  have similar aging and reclaiming characteristics as every
  other node.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/vmscan.c | 292 +++++++++++++++++++++---------------------------------------
 1 file changed, 101 insertions(+), 191 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c6e61dae382b..7b382b90b145 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2980,7 +2980,8 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 }
 #endif
 
-static void age_active_anon(struct zone *zone, struct scan_control *sc)
+static void age_active_anon(struct pglist_data *pgdat,
+				struct zone *zone, struct scan_control *sc)
 {
 	struct mem_cgroup *memcg;
 
@@ -2999,85 +3000,15 @@ static void age_active_anon(struct zone *zone, struct scan_control *sc)
 	} while (memcg);
 }
 
-static bool zone_balanced(struct zone *zone, int order, bool highorder,
+static bool zone_balanced(struct zone *zone, int order,
 			unsigned long balance_gap, int classzone_idx)
 {
 	unsigned long mark = high_wmark_pages(zone) + balance_gap;
 
-	/*
-	 * When checking from pgdat_balanced(), kswapd should stop and sleep
-	 * when it reaches the high order-0 watermark and let kcompactd take
-	 * over. Other callers such as wakeup_kswapd() want to determine the
-	 * true high-order watermark.
-	 */
-	if (IS_ENABLED(CONFIG_COMPACTION) && !highorder) {
-		mark += (1UL << order);
-		order = 0;
-	}
-
 	return zone_watermark_ok_safe(zone, order, mark, classzone_idx);
 }
 
 /*
- * pgdat_balanced() is used when checking if a node is balanced.
- *
- * For order-0, all zones must be balanced!
- *
- * For high-order allocations only zones that meet watermarks and are in a
- * zone allowed by the callers classzone_idx are added to balanced_pages. The
- * total of balanced pages must be at least 25% of the zones allowed by
- * classzone_idx for the node to be considered balanced. Forcing all zones to
- * be balanced for high orders can cause excessive reclaim when there are
- * imbalanced zones.
- * The choice of 25% is due to
- *   o a 16M DMA zone that is balanced will not balance a zone on any
- *     reasonable sized machine
- *   o On all other machines, the top zone must be at least a reasonable
- *     percentage of the middle zones. For example, on 32-bit x86, highmem
- *     would need to be at least 256M for it to be balance a whole node.
- *     Similarly, on x86-64 the Normal zone would need to be at least 1G
- *     to balance a node on its own. These seemed like reasonable ratios.
- */
-static bool pgdat_balanced(pg_data_t *pgdat, int order, int classzone_idx)
-{
-	unsigned long managed_pages = 0;
-	unsigned long balanced_pages = 0;
-	int i;
-
-	/* Check the watermark levels */
-	for (i = 0; i <= classzone_idx; i++) {
-		struct zone *zone = pgdat->node_zones + i;
-
-		if (!populated_zone(zone))
-			continue;
-
-		managed_pages += zone->managed_pages;
-
-		/*
-		 * A special case here:
-		 *
-		 * balance_pgdat() skips over all_unreclaimable after
-		 * DEF_PRIORITY. Effectively, it considers them balanced so
-		 * they must be considered balanced here as well!
-		 */
-		if (!pgdat_reclaimable(zone->zone_pgdat)) {
-			balanced_pages += zone->managed_pages;
-			continue;
-		}
-
-		if (zone_balanced(zone, order, false, 0, i))
-			balanced_pages += zone->managed_pages;
-		else if (!order)
-			return false;
-	}
-
-	if (order)
-		return balanced_pages >= (managed_pages >> 2);
-	else
-		return true;
-}
-
-/*
  * Prepare kswapd for sleeping. This verifies that there are no processes
  * waiting in throttle_direct_reclaim() and that watermarks have been met.
  *
@@ -3086,6 +3017,8 @@ static bool pgdat_balanced(pg_data_t *pgdat, int order, int classzone_idx)
 static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining,
 					int classzone_idx)
 {
+	int i;
+
 	/* If a direct reclaimer woke kswapd within HZ/10, it's premature */
 	if (remaining)
 		return false;
@@ -3106,101 +3039,90 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining,
 	if (waitqueue_active(&pgdat->pfmemalloc_wait))
 		wake_up_all(&pgdat->pfmemalloc_wait);
 
-	return pgdat_balanced(pgdat, order, classzone_idx);
+	for (i = 0; i <= classzone_idx; i++) {
+		struct zone *zone = pgdat->node_zones + i;
+
+		if (!populated_zone(zone))
+			continue;
+
+		if (zone_balanced(zone, order, 0, classzone_idx))
+			return true;
+	}
+
+	return false;
 }
 
 /*
- * kswapd shrinks the zone by the number of pages required to reach
- * the high watermark.
+ * kswapd shrinks a node of pages that are at or below the highest usable
+ * zone that is currently unbalanced.
  *
  * Returns true if kswapd scanned at least the requested number of pages to
  * reclaim or if the lack of progress was due to pages under writeback.
  * This is used to determine if the scanning priority needs to be raised.
  */
-static bool kswapd_shrink_zone(struct zone *zone,
+static bool kswapd_shrink_node(pg_data_t *pgdat,
 			       int classzone_idx,
 			       struct scan_control *sc)
 {
-	unsigned long balance_gap;
-	bool lowmem_pressure;
-	struct pglist_data *pgdat = zone->zone_pgdat;
+	struct zone *zone;
+	int z;
 
-	/* Reclaim above the high watermark. */
-	sc->nr_to_reclaim = max(SWAP_CLUSTER_MAX, high_wmark_pages(zone));
+	/* Reclaim a number of pages proportional to the number of zones */
+	sc->nr_to_reclaim = 0;
+	for (z = 0; z <= classzone_idx; z++) {
+		zone = pgdat->node_zones + z;
+		if (!populated_zone(zone))
+			continue;
 
-	/*
-	 * We put equal pressure on every zone, unless one zone has way too
-	 * many pages free already. The "too many pages" is defined as the
-	 * high wmark plus a "gap" where the gap is either the low
-	 * watermark or 1% of the zone, whichever is smaller.
-	 */
-	balance_gap = min(low_wmark_pages(zone), DIV_ROUND_UP(
-			zone->managed_pages, KSWAPD_ZONE_BALANCE_GAP_RATIO));
+		sc->nr_to_reclaim += max(high_wmark_pages(zone), SWAP_CLUSTER_MAX);
+	}
 
 	/*
-	 * If there is no low memory pressure or the zone is balanced then no
-	 * reclaim is necessary
+	 * Historically care was taken to put equal pressure on all zones but
+	 * now pressure is applied based on node LRU order.
 	 */
-	lowmem_pressure = (buffer_heads_over_limit && is_highmem(zone));
-	if (!lowmem_pressure && zone_balanced(zone, sc->order, false,
-						balance_gap, classzone_idx))
-		return true;
-
-	shrink_node(zone->zone_pgdat, sc, classzone_idx);
-
-	/* TODO: ANOMALY */
-	clear_bit(PGDAT_WRITEBACK, &pgdat->flags);
+	shrink_node(pgdat, sc, classzone_idx);
 
 	/*
-	 * If a zone reaches its high watermark, consider it to be no longer
-	 * congested. It's possible there are dirty pages backed by congested
-	 * BDIs but as pressure is relieved, speculatively avoid congestion
-	 * waits.
+	 * Fragmentation may mean that the system cannot be rebalanced for
+	 * high-order allocations. If twice the allocation size has been
+	 * reclaimed then recheck watermarks only at order-0 to prevent
+	 * excessive reclaim. Assume that a process requested a high-order
+	 * can direct reclaim/compact.
 	 */
-	if (pgdat_reclaimable(zone->zone_pgdat) &&
-	    zone_balanced(zone, sc->order, false, 0, classzone_idx)) {
-		clear_bit(PGDAT_CONGESTED, &pgdat->flags);
-		clear_bit(PGDAT_DIRTY, &pgdat->flags);
-	}
+	if (sc->order && sc->nr_reclaimed >= 2UL << sc->order)
+		sc->order = 0;
 
 	return sc->nr_scanned >= sc->nr_to_reclaim;
 }
 
 /*
- * For kswapd, balance_pgdat() will work across all this node's zones until
- * they are all at high_wmark_pages(zone).
- *
- * Returns the highest zone idx kswapd was reclaiming at
+ * For kswapd, balance_pgdat() will reclaim pages across a node from zones
+ * that are eligible for use by the caller until at least one zone is
+ * balanced.
  *
- * There is special handling here for zones which are full of pinned pages.
- * This can happen if the pages are all mlocked, or if they are all used by
- * device drivers (say, ZONE_DMA).  Or if they are all in use by hugetlb.
- * What we do is to detect the case where all pages in the zone have been
- * scanned twice and there has been zero successful reclaim.  Mark the zone as
- * dead and from now on, only perform a short scan.  Basically we're polling
- * the zone for when the problem goes away.
+ * Returns the order kswapd finished reclaiming at.
  *
  * kswapd scans the zones in the highmem->normal->dma direction.  It skips
  * zones which have free_pages > high_wmark_pages(zone), but once a zone is
- * found to have free_pages <= high_wmark_pages(zone), we scan that zone and the
- * lower zones regardless of the number of free pages in the lower zones. This
- * interoperates with the page allocator fallback scheme to ensure that aging
- * of pages is balanced across the zones.
+ * found to have free_pages <= high_wmark_pages(zone), any page is that zone
+ * or lower is eligible for reclaim until at least one usable zone is
+ * balanced.
  */
 static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 {
 	int i;
-	int end_zone = 0;	/* Inclusive.  0 = ZONE_DMA */
 	unsigned long nr_soft_reclaimed;
 	unsigned long nr_soft_scanned;
+	struct zone *zone;
 	struct scan_control sc = {
 		.gfp_mask = GFP_KERNEL,
-		.reclaim_idx = MAX_NR_ZONES - 1,
 		.order = order,
 		.priority = DEF_PRIORITY,
 		.may_writepage = !laptop_mode,
 		.may_unmap = 1,
 		.may_swap = 1,
+		.reclaim_idx = classzone_idx,
 	};
 	count_vm_event(PAGEOUTRUN);
 
@@ -3211,21 +3133,10 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 
 		/* Scan from the highest requested zone to dma */
 		for (i = classzone_idx; i >= 0; i--) {
-			struct zone *zone = pgdat->node_zones + i;
-
+			zone = pgdat->node_zones + i;
 			if (!populated_zone(zone))
 				continue;
 
-			if (sc.priority != DEF_PRIORITY &&
-			    !pgdat_reclaimable(zone->zone_pgdat))
-				continue;
-
-			/*
-			 * Do some background aging of the anon list, to give
-			 * pages a chance to be referenced before reclaiming.
-			 */
-			age_active_anon(zone, &sc);
-
 			/*
 			 * If the number of buffer_heads in the machine
 			 * exceeds the maximum allowed level and this node
@@ -3233,19 +3144,17 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 			 * it to relieve lowmem pressure.
 			 */
 			if (buffer_heads_over_limit && is_highmem_idx(i)) {
-				end_zone = i;
+				classzone_idx = i;
 				break;
 			}
 
-			if (!zone_balanced(zone, order, false, 0, 0)) {
-				end_zone = i;
+			if (!zone_balanced(zone, order, 0, 0)) {
+				classzone_idx = i;
 				break;
 			} else {
 				/*
-				 * If balanced, clear the dirty and congested
-				 * flags
-				 *
-				 * TODO: ANOMALY
+				 * If any eligible zone is balanced then the
+				 * node is not considered congested or dirty.
 				 */
 				clear_bit(PGDAT_CONGESTED, &zone->zone_pgdat->flags);
 				clear_bit(PGDAT_DIRTY, &zone->zone_pgdat->flags);
@@ -3256,51 +3165,34 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 			goto out;
 
 		/*
+		 * Do some background aging of the anon list, to give
+		 * pages a chance to be referenced before reclaiming. All
+		 * pages are rotated regardless of classzone as this is
+		 * about consistent aging.
+		 */
+		age_active_anon(pgdat, &pgdat->node_zones[MAX_NR_ZONES - 1], &sc);
+
+		/*
 		 * If we're getting trouble reclaiming, start doing writepage
 		 * even in laptop mode.
 		 */
-		if (sc.priority < DEF_PRIORITY - 2)
+		if (sc.priority < DEF_PRIORITY - 2 || !pgdat_reclaimable(pgdat))
 			sc.may_writepage = 1;
 
+		/* Call soft limit reclaim before calling shrink_node. */
+		sc.nr_scanned = 0;
+		nr_soft_scanned = 0;
+		nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone, sc.order,
+						sc.gfp_mask, &nr_soft_scanned);
+		sc.nr_reclaimed += nr_soft_reclaimed;
+
 		/*
-		 * Continue scanning in the highmem->dma direction stopping at
-		 * the last zone which needs scanning. This may reclaim lowmem
-		 * pages that are not necessary for zone balancing but it
-		 * preserves LRU ordering. It is assumed that the bulk of
-		 * allocation requests can use arbitrary zones with the
-		 * possible exception of big highmem:lowmem configurations.
+		 * There should be no need to raise the scanning priority if
+		 * enough pages are already being scanned that that high
+		 * watermark would be met at 100% efficiency.
 		 */
-		for (i = end_zone; i >= 0; i--) {
-			struct zone *zone = pgdat->node_zones + i;
-
-			if (!populated_zone(zone))
-				continue;
-
-			if (sc.priority != DEF_PRIORITY &&
-			    !pgdat_reclaimable(zone->zone_pgdat))
-				continue;
-
-			sc.nr_scanned = 0;
-			sc.reclaim_idx = i;
-
-			nr_soft_scanned = 0;
-			/*
-			 * Call soft limit reclaim before calling shrink_zone.
-			 */
-			nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone,
-							order, sc.gfp_mask,
-							&nr_soft_scanned);
-			sc.nr_reclaimed += nr_soft_reclaimed;
-
-			/*
-			 * There should be no need to raise the scanning
-			 * priority if enough pages are already being scanned
-			 * that that high watermark would be met at 100%
-			 * efficiency.
-			 */
-			if (kswapd_shrink_zone(zone, end_zone, &sc))
-				raise_priority = false;
-		}
+		if (kswapd_shrink_node(pgdat, classzone_idx, &sc))
+			raise_priority = false;
 
 		/*
 		 * If the low watermark is met there is no need for processes
@@ -3316,20 +3208,37 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 			break;
 
 		/*
+		 * Stop reclaiming if any eligible zone is balanced and clear
+		 * node writeback or congested.
+		 */
+		for (i = 0; i <= classzone_idx; i++) {
+			zone = pgdat->node_zones + i;
+			if (!populated_zone(zone))
+				continue;
+
+			if (zone_balanced(zone, sc.order, 0, classzone_idx)) {
+				clear_bit(PGDAT_CONGESTED, &pgdat->flags);
+				clear_bit(PGDAT_DIRTY, &pgdat->flags);
+				goto out;
+			}
+		}
+
+		/*
 		 * Raise priority if scanning rate is too low or there was no
 		 * progress in reclaiming pages
 		 */
 		if (raise_priority || !sc.nr_reclaimed)
 			sc.priority--;
-	} while (sc.priority >= 1 &&
-			!pgdat_balanced(pgdat, order, classzone_idx));
+	} while (sc.priority >= 1);
 
 out:
 	/*
-	 * Return the highest zone idx we were reclaiming at so
-	 * prepare_kswapd_sleep() makes the same decisions as here.
+	 * Return the order kswapd stopped reclaiming at as
+	 * prepare_kswapd_sleep() takes it into account. If another caller
+	 * entered the allocator slow path while kswapd was awake, order will
+	 * remain at the higher level.
 	 */
-	return end_zone;
+	return sc.order;
 }
 
 static void kswapd_try_to_sleep(pg_data_t *pgdat, int order,
@@ -3486,8 +3395,9 @@ static int kswapd(void *p)
 		 */
 		if (!ret) {
 			trace_mm_vmscan_kswapd_wake(pgdat->node_id, order);
-			balanced_classzone_idx = balance_pgdat(pgdat, order,
-								classzone_idx);
+
+			/* return value ignored until next patch */
+			balance_pgdat(pgdat, order, classzone_idx);
 		}
 	}
 
@@ -3517,7 +3427,7 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
 	}
 	if (!waitqueue_active(&pgdat->kswapd_wait))
 		return;
-	if (zone_balanced(zone, order, true, 0, 0))
+	if (zone_balanced(zone, order, 0, 0))
 		return;
 
 	trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order);
-- 
2.6.4

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#1439241 — [PATCH 30/34] mm: page_alloc: cache the last node whose dirty limit is reached

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:50 +0200
Subject[PATCH 30/34] mm: page_alloc: cache the last node whose dirty limit is reached
Message-ID<rSAA1-2Xn-3@gated-at.bofh.it>
In reply to#1439225
If a page is about to be dirtied then the page allocator attempts to limit
the total number of dirty pages that exists in any given zone.  The call
to node_dirty_ok is expensive so this patch records if the last pgdat
examined hit the dirty limits.  In some cases, this reduces the number of
calls to node_dirty_ok().

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/page_alloc.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 565f08832853..958424fc64be 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2891,6 +2891,8 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
 {
 	struct zoneref *z = ac->preferred_zoneref;
 	struct zone *zone;
+	struct pglist_data *last_pgdat_dirty_limit = NULL;
+
 	/*
 	 * Scan zonelist, looking for a zone with enough free.
 	 * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
@@ -2923,8 +2925,15 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
 		 * will require awareness of nodes in the
 		 * dirty-throttling and the flusher threads.
 		 */
-		if (ac->spread_dirty_pages && !node_dirty_ok(zone->zone_pgdat))
-			continue;
+		if (ac->spread_dirty_pages) {
+			if (last_pgdat_dirty_limit == zone->zone_pgdat)
+				continue;
+
+			if (!node_dirty_ok(zone->zone_pgdat)) {
+				last_pgdat_dirty_limit = zone->zone_pgdat;
+				continue;
+			}
+		}
 
 		mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
 		if (!zone_watermark_fast(zone, order, mark,
-- 
2.6.4

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#1439242 — [PATCH 31/34] mm: vmstat: replace __count_zone_vm_events with a zone id equivalent

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:50 +0200
Subject[PATCH 31/34] mm: vmstat: replace __count_zone_vm_events with a zone id equivalent
Message-ID<rSAA1-2Xn-15@gated-at.bofh.it>
In reply to#1439225
This is partially a preparation patch for more vmstat work but it also has
the slight advantage that __count_zid_vm_events is cheaper to calculate
than __count_zone_vm_events().

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/vmstat.h | 5 ++---
 mm/page_alloc.c        | 2 +-
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 6b7975cd98aa..613771909b6e 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -101,9 +101,8 @@ static inline void vm_events_fold_cpu(int cpu)
 #define count_vm_vmacache_event(x) do {} while (0)
 #endif
 
-#define __count_zone_vm_events(item, zone, delta) \
-		__count_vm_events(item##_NORMAL - ZONE_NORMAL + \
-		zone_idx(zone), delta)
+#define __count_zid_vm_events(item, zid, delta) \
+	__count_vm_events(item##_NORMAL - ZONE_NORMAL + zid, delta)
 
 /*
  * Zone and node-based page accounting with per cpu differentials.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 958424fc64be..030114f55b0e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2659,7 +2659,7 @@ struct page *buffered_rmqueue(struct zone *preferred_zone,
 					  get_pcppage_migratetype(page));
 	}
 
-	__count_zone_vm_events(PGALLOC, zone, 1 << order);
+	__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
 	zone_statistics(preferred_zone, zone, gfp_flags);
 	local_irq_restore(flags);
 
-- 
2.6.4

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#1439243 — [PATCH 34/34] mm, vmstat: remove zone and node double accounting by approximating retries

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:50 +0200
Subject[PATCH 34/34] mm, vmstat: remove zone and node double accounting by approximating retries
Message-ID<rSAA1-2Xn-5@gated-at.bofh.it>
In reply to#1439225
The number of LRU pages, dirty pages and writeback pages must be accounted
for on both zones and nodes because of the reclaim retry logic, compaction
retry logic and highmem calculations all depending on per-zone stats.

Many lowmem allocations are immune from OOM kill due to a check in
__alloc_pages_may_oom for (ac->high_zoneidx < ZONE_NORMAL) since commit
03668b3ceb0c ("oom: avoid oom killer for lowmem allocations"). The exception
is costly high-order allocations or allocations that cannot fail. If the
__alloc_pages_may_oom avoids OOM-kill for low-order lowmem allocations
then it would fall through to __alloc_pages_direct_compact.

This patch will blindly retry reclaim for zone-constrained allocations
in should_reclaim_retry up to MAX_RECLAIM_RETRIES. This is not ideal but
without per-zone stats there are not many alternatives. The impact it that
zone-constrained allocations may delay before considering the OOM killer.

As there is no guarantee enough memory can ever be freed to satisfy
compaction, this patch avoids retrying compaction for zone-contrained
allocations.

In combination, that means that the per-node stats can be used when deciding
whether to continue reclaim using a rough approximation.  While it is
possible this will make the wrong decision on occasion, it will not infinite
loop as the number of reclaim attempts is capped by MAX_RECLAIM_RETRIES.

The final step is calculating the number of dirtyable highmem pages. As
those calculations only care about the global count of file pages in
highmem. This patch uses a global counter used instead of per-zone stats
as it is sufficient.

In combination, this allows the per-zone LRU and dirty state counters to
be removed.

Suggested by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
---
 include/linux/mm_inline.h | 24 +++++++++++++++++++++---
 include/linux/mmzone.h    |  4 ----
 include/linux/swap.h      |  1 -
 mm/compaction.c           | 20 +++++++++++++++++++-
 mm/migrate.c              |  2 --
 mm/page-writeback.c       | 13 +++++--------
 mm/page_alloc.c           | 47 +++++++++++++++++++++++++++++++++++++++--------
 mm/vmscan.c               | 16 ----------------
 mm/vmstat.c               |  3 ---
 9 files changed, 84 insertions(+), 46 deletions(-)

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 9aadcc781857..ccd40e357b56 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -4,6 +4,26 @@
 #include <linux/huge_mm.h>
 #include <linux/swap.h>
 
+#ifdef CONFIG_HIGHMEM
+extern atomic_t highmem_file_pages;
+
+static inline void acct_highmem_file_pages(int zid, enum lru_list lru,
+							int nr_pages)
+{
+	if (is_highmem_idx(zid) && is_file_lru(lru)) {
+		if (nr_pages > 0)
+			atomic_add(nr_pages, &highmem_file_pages);
+		else
+			atomic_sub(nr_pages, &highmem_file_pages);
+	}
+}
+#else
+static inline void acct_highmem_file_pages(int zid, enum lru_list lru,
+							int nr_pages)
+{
+}
+#endif
+
 /**
  * page_is_file_cache - should the page be on a file LRU or anon LRU?
  * @page: the page to test
@@ -29,9 +49,7 @@ static __always_inline void __update_lru_size(struct lruvec *lruvec,
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 
 	__mod_node_page_state(pgdat, NR_LRU_BASE + lru, nr_pages);
-	__mod_zone_page_state(&pgdat->node_zones[zid],
-		NR_ZONE_LRU_BASE + !!is_file_lru(lru),
-		nr_pages);
+	acct_highmem_file_pages(zid, lru, nr_pages);
 }
 
 static __always_inline void update_lru_size(struct lruvec *lruvec,
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index bd33e6f1bed0..a3b7f45aac56 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -110,10 +110,6 @@ struct zone_padding {
 enum zone_stat_item {
 	/* First 128 byte cacheline (assuming 64 bit words) */
 	NR_FREE_PAGES,
-	NR_ZONE_LRU_BASE, /* Used only for compaction and reclaim retry */
-	NR_ZONE_LRU_ANON = NR_ZONE_LRU_BASE,
-	NR_ZONE_LRU_FILE,
-	NR_ZONE_WRITE_PENDING,	/* Count of dirty, writeback and unstable pages */
 	NR_MLOCK,		/* mlock()ed pages found and moved off LRU */
 	NR_SLAB_RECLAIMABLE,
 	NR_SLAB_UNRECLAIMABLE,
diff --git a/include/linux/swap.h b/include/linux/swap.h
index b17cc4830fa6..cc753c639e3d 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -307,7 +307,6 @@ extern void lru_cache_add_active_or_unevictable(struct page *page,
 						struct vm_area_struct *vma);
 
 /* linux/mm/vmscan.c */
-extern unsigned long zone_reclaimable_pages(struct zone *zone);
 extern unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat);
 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 					gfp_t gfp_mask, nodemask_t *mask);
diff --git a/mm/compaction.c b/mm/compaction.c
index a0bd85712516..640532831b94 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1446,6 +1446,11 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
 {
 	struct zone *zone;
 	struct zoneref *z;
+	pg_data_t *last_pgdat = NULL;
+
+	/* Do not retry compaction for zone-constrained allocations */
+	if (ac->high_zoneidx < ZONE_NORMAL)
+		return false;
 
 	/*
 	 * Make sure at least one zone would pass __compaction_suitable if we continue
@@ -1456,14 +1461,27 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
 		unsigned long available;
 		enum compact_result compact_result;
 
+		if (last_pgdat == zone->zone_pgdat)
+			continue;
+
+		/*
+		 * This over-estimates the number of pages available for
+		 * reclaim/compaction but walking the LRU would take too
+		 * long. The consequences are that compaction may retry
+		 * longer than it should for a zone-constrained allocation
+		 * request.
+		 */
+		last_pgdat = zone->zone_pgdat;
+		available = pgdat_reclaimable_pages(zone->zone_pgdat) / order;
+
 		/*
 		 * Do not consider all the reclaimable memory because we do not
 		 * want to trash just for a single high order allocation which
 		 * is even not guaranteed to appear even if __compaction_suitable
 		 * is happy about the watermark check.
 		 */
-		available = zone_reclaimable_pages(zone) / order;
 		available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
+		available = min(zone->managed_pages, available);
 		compact_result = __compaction_suitable(zone, order, alloc_flags,
 				ac_classzone_idx(ac), available);
 		if (compact_result != COMPACT_SKIPPED &&
diff --git a/mm/migrate.c b/mm/migrate.c
index c77997dc6ed7..ed2f85e61de1 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -513,9 +513,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
 		}
 		if (dirty && mapping_cap_account_dirty(mapping)) {
 			__dec_node_state(oldzone->zone_pgdat, NR_FILE_DIRTY);
-			__dec_zone_state(oldzone, NR_ZONE_WRITE_PENDING);
 			__inc_node_state(newzone->zone_pgdat, NR_FILE_DIRTY);
-			__dec_zone_state(newzone, NR_ZONE_WRITE_PENDING);
 		}
 	}
 	local_irq_enable();
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 3c02aa603f5a..0bca2376bd42 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -299,6 +299,9 @@ static unsigned long node_dirtyable_memory(struct pglist_data *pgdat)
 
 	return nr_pages;
 }
+#ifdef CONFIG_HIGHMEM
+atomic_t highmem_file_pages;
+#endif
 
 static unsigned long highmem_dirtyable_memory(unsigned long total)
 {
@@ -306,18 +309,17 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
 	int node;
 	unsigned long x = 0;
 	int i;
+	unsigned long dirtyable = atomic_read(&highmem_file_pages);
 
 	for_each_node_state(node, N_HIGH_MEMORY) {
 		for (i = ZONE_NORMAL + 1; i < MAX_NR_ZONES; i++) {
 			struct zone *z;
-			unsigned long dirtyable;
 
 			if (!is_highmem_idx(i))
 				continue;
 
 			z = &NODE_DATA(node)->node_zones[i];
-			dirtyable = zone_page_state(z, NR_FREE_PAGES) +
-				zone_page_state(z, NR_ZONE_LRU_FILE);
+			dirtyable += zone_page_state(z, NR_FREE_PAGES);
 
 			/* watch for underflows */
 			dirtyable -= min(dirtyable, high_wmark_pages(z));
@@ -2460,7 +2462,6 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 
 		mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_DIRTY);
 		__inc_node_page_state(page, NR_FILE_DIRTY);
-		__inc_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 		__inc_node_page_state(page, NR_DIRTIED);
 		__inc_wb_stat(wb, WB_RECLAIMABLE);
 		__inc_wb_stat(wb, WB_DIRTIED);
@@ -2482,7 +2483,6 @@ void account_page_cleaned(struct page *page, struct address_space *mapping,
 	if (mapping_cap_account_dirty(mapping)) {
 		mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
 		dec_node_page_state(page, NR_FILE_DIRTY);
-		dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 		dec_wb_stat(wb, WB_RECLAIMABLE);
 		task_io_account_cancelled_write(PAGE_SIZE);
 	}
@@ -2739,7 +2739,6 @@ int clear_page_dirty_for_io(struct page *page)
 		if (TestClearPageDirty(page)) {
 			mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
 			dec_node_page_state(page, NR_FILE_DIRTY);
-			dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 			dec_wb_stat(wb, WB_RECLAIMABLE);
 			ret = 1;
 		}
@@ -2786,7 +2785,6 @@ int test_clear_page_writeback(struct page *page)
 	if (ret) {
 		mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
 		dec_node_page_state(page, NR_WRITEBACK);
-		dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 		inc_node_page_state(page, NR_WRITTEN);
 	}
 	unlock_page_memcg(page);
@@ -2841,7 +2839,6 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
 	if (!ret) {
 		mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
 		inc_node_page_state(page, NR_WRITEBACK);
-		inc_zone_page_state(page, NR_ZONE_WRITE_PENDING);
 	}
 	unlock_page_memcg(page);
 	return ret;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 030114f55b0e..a702c31d2df4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3445,6 +3445,7 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
 {
 	struct zone *zone;
 	struct zoneref *z;
+	pg_data_t *current_pgdat = NULL;
 
 	/*
 	 * Make sure we converge to OOM if we cannot make any progress
@@ -3454,6 +3455,15 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
 		return false;
 
 	/*
+	 * Blindly retry lowmem allocation requests that are often ignored by
+	 * the OOM killer up to MAX_RECLAIM_RETRIES as we not have a reliable
+	 * and fast means of calculating reclaimable, dirty and writeback pages
+	 * in eligible zones.
+	 */
+	if (ac->high_zoneidx < ZONE_NORMAL)
+		goto out;
+
+	/*
 	 * Keep reclaiming pages while there is a chance this will lead somewhere.
 	 * If none of the target zones can satisfy our allocation request even
 	 * if all reclaimable pages are considered then we are screwed and have
@@ -3463,18 +3473,38 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
 					ac->nodemask) {
 		unsigned long available;
 		unsigned long reclaimable;
+		int zid;
 
-		available = reclaimable = zone_reclaimable_pages(zone);
+		if (current_pgdat == zone->zone_pgdat)
+			continue;
+
+		current_pgdat = zone->zone_pgdat;
+		available = reclaimable = pgdat_reclaimable_pages(current_pgdat);
 		available -= DIV_ROUND_UP(no_progress_loops * available,
 					  MAX_RECLAIM_RETRIES);
-		available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
+
+		/* Account for all free pages on eligible zones */
+		for (zid = 0; zid <= zone_idx(zone); zid++) {
+			struct zone *acct_zone = &current_pgdat->node_zones[zid];
+
+			available += zone_page_state_snapshot(acct_zone, NR_FREE_PAGES);
+		}
 
 		/*
 		 * Would the allocation succeed if we reclaimed the whole
-		 * available?
+		 * available? This is approximate because there is no
+		 * accurate count of reclaimable pages per zone.
 		 */
-		if (__zone_watermark_ok(zone, order, min_wmark_pages(zone),
-				ac_classzone_idx(ac), alloc_flags, available)) {
+		for (zid = 0; zid <= zone_idx(zone); zid++) {
+			struct zone *check_zone = &current_pgdat->node_zones[zid];
+			unsigned long estimate;
+
+			estimate = min(check_zone->managed_pages, available);
+			if (!__zone_watermark_ok(check_zone, order,
+					min_wmark_pages(check_zone), ac_classzone_idx(ac),
+					alloc_flags, estimate))
+				continue;
+
 			/*
 			 * If we didn't make any progress and have a lot of
 			 * dirty + writeback pages then we should wait for
@@ -3484,15 +3514,16 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
 			if (!did_some_progress) {
 				unsigned long write_pending;
 
-				write_pending = zone_page_state_snapshot(zone,
-							NR_ZONE_WRITE_PENDING);
+				write_pending =
+					node_page_state(current_pgdat, NR_WRITEBACK) +
+					node_page_state(current_pgdat, NR_FILE_DIRTY);
 
 				if (2 * write_pending > reclaimable) {
 					congestion_wait(BLK_RW_ASYNC, HZ/10);
 					return true;
 				}
 			}
-
+out:
 			/*
 			 * Memory allocation/reclaim might be called from a WQ
 			 * context and the current implementation of the WQ
diff --git a/mm/vmscan.c b/mm/vmscan.c
index a8b432ff0d14..d079210d46ee 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -194,22 +194,6 @@ static bool sane_reclaim(struct scan_control *sc)
 }
 #endif
 
-/*
- * This misses isolated pages which are not accounted for to save counters.
- * As the data only determines if reclaim or compaction continues, it is
- * not expected that isolated pages will be a dominating factor.
- */
-unsigned long zone_reclaimable_pages(struct zone *zone)
-{
-	unsigned long nr;
-
-	nr = zone_page_state_snapshot(zone, NR_ZONE_LRU_FILE);
-	if (get_nr_swap_pages() > 0)
-		nr += zone_page_state_snapshot(zone, NR_ZONE_LRU_ANON);
-
-	return nr;
-}
-
 unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat)
 {
 	unsigned long nr;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 60372f31fee3..7415775faf08 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -921,9 +921,6 @@ int fragmentation_index(struct zone *zone, unsigned int order)
 const char * const vmstat_text[] = {
 	/* enum zone_stat_item countes */
 	"nr_free_pages",
-	"nr_zone_anon_lru",
-	"nr_zone_file_lru",
-	"nr_zone_write_pending",
 	"nr_mlock",
 	"nr_slab_reclaimable",
 	"nr_slab_unreclaimable",
-- 
2.6.4

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#1439244 — [PATCH 10/34] mm, vmscan: by default have direct reclaim only shrink once per node

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:50 +0200
Subject[PATCH 10/34] mm, vmscan: by default have direct reclaim only shrink once per node
Message-ID<rSAA1-2Xn-7@gated-at.bofh.it>
In reply to#1439225
Direct reclaim iterates over all zones in the zonelist and shrinking them
but this is in conflict with node-based reclaim.  In the default case,
only shrink once per node.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/vmscan.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 905c60473126..01fe4708e404 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2552,14 +2552,6 @@ static inline bool compaction_ready(struct zone *zone, int order, int classzone_
  * try to reclaim pages from zones which will satisfy the caller's allocation
  * request.
  *
- * We reclaim from a zone even if that zone is over high_wmark_pages(zone).
- * Because:
- * a) The caller may be trying to free *extra* pages to satisfy a higher-order
- *    allocation or
- * b) The target zone may be at high_wmark_pages(zone) but the lower zones
- *    must go *over* high_wmark_pages(zone) to satisfy the `incremental min'
- *    zone defense algorithm.
- *
  * If a zone is deemed to be full of pinned pages then just give it a light
  * scan then give up on it.
  */
@@ -2571,6 +2563,7 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 	unsigned long nr_soft_scanned;
 	gfp_t orig_mask;
 	enum zone_type classzone_idx;
+	pg_data_t *last_pgdat = NULL;
 
 	/*
 	 * If the number of buffer_heads in the machine exceeds the maximum
@@ -2630,6 +2623,15 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 			}
 
 			/*
+			 * Shrink each node in the zonelist once. If the
+			 * zonelist is ordered by zone (not the default) then a
+			 * node may be shrunk multiple times but in that case
+			 * the user prefers lower zones being preserved.
+			 */
+			if (zone->zone_pgdat == last_pgdat)
+				continue;
+
+			/*
 			 * This steals pages from memory cgroups over softlimit
 			 * and returns the number of reclaimed pages and
 			 * scanned pages. This works for global memory pressure
@@ -2644,6 +2646,10 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 			/* need some check for avoid more shrink_zone() */
 		}
 
+		/* See comment about same check for global reclaim above */
+		if (zone->zone_pgdat == last_pgdat)
+			continue;
+		last_pgdat = zone->zone_pgdat;
 		shrink_node(zone->zone_pgdat, sc, classzone_idx);
 	}
 
-- 
2.6.4

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#1439245 — [PATCH 32/34] mm: vmstat: account per-zone stalls and pages skipped during reclaim

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:50 +0200
Subject[PATCH 32/34] mm: vmstat: account per-zone stalls and pages skipped during reclaim
Message-ID<rSAA1-2Xn-11@gated-at.bofh.it>
In reply to#1439225
The vmstat allocstall was fairly useful in the general sense but
node-based LRUs change that.  It's important to know if a stall was for an
address-limited allocation request as this will require skipping pages
from other zones.  This patch adds pgstall_* counters to replace
allocstall.  The sum of the counters will equal the old allocstall so it
can be trivially recalculated.  A high number of address-limited
allocation requests may result in a lot of useless LRU scanning for
suitable pages.

As address-limited allocations require pages to be skipped, it's important
to know how much useless LRU scanning took place so this patch adds
pgskip* counters.  This yields the following model

1. The number of address-space limited stalls can be accounted for (pgstall)
2. The amount of useless work required to reclaim the data is accounted (pgskip)
3. The total number of scans is available from pgscan_kswapd and pgscan_direct
   so from that the ratio of useful to useless scans can be calculated.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/vm_event_item.h |  4 +++-
 mm/vmscan.c                   | 15 +++++++++++++--
 mm/vmstat.c                   |  3 ++-
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 1798ff542517..6d47f66f0e9c 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -23,6 +23,8 @@
 
 enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		FOR_ALL_ZONES(PGALLOC),
+		FOR_ALL_ZONES(PGSTALL),
+		FOR_ALL_ZONES(PGSCAN_SKIP),
 		PGFREE, PGACTIVATE, PGDEACTIVATE,
 		PGFAULT, PGMAJFAULT,
 		PGLAZYFREED,
@@ -37,7 +39,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 #endif
 		PGINODESTEAL, SLABS_SCANNED, KSWAPD_INODESTEAL,
 		KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY,
-		PAGEOUTRUN, ALLOCSTALL, PGROTATED,
+		PAGEOUTRUN, PGROTATED,
 		DROP_PAGECACHE, DROP_SLAB,
 #ifdef CONFIG_NUMA_BALANCING
 		NUMA_PTE_UPDATES,
diff --git a/mm/vmscan.c b/mm/vmscan.c
index bbd77fa4ec6a..a8b432ff0d14 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1394,6 +1394,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 	struct list_head *src = &lruvec->lists[lru];
 	unsigned long nr_taken = 0;
 	unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };
+	unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };
 	unsigned long scan, nr_pages;
 	LIST_HEAD(pages_skipped);
 
@@ -1408,6 +1409,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 
 		if (page_zonenum(page) > sc->reclaim_idx) {
 			list_move(&page->lru, &pages_skipped);
+			nr_skipped[page_zonenum(page)]++;
 			continue;
 		}
 
@@ -1436,8 +1438,17 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 	 * scanning would soon rescan the same pages to skip and put the
 	 * system at risk of premature OOM.
 	 */
-	if (!list_empty(&pages_skipped))
+	if (!list_empty(&pages_skipped)) {
+		int zid;
+
 		list_splice(&pages_skipped, src);
+		for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+			if (!nr_skipped[zid])
+				continue;
+
+			__count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]);
+		}
+	}
 	*nr_scanned = scan;
 	trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, scan,
 				    nr_taken, mode, is_file_lru(lru));
@@ -2679,7 +2690,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
 	delayacct_freepages_start();
 
 	if (global_reclaim(sc))
-		count_vm_event(ALLOCSTALL);
+		__count_zid_vm_events(PGSTALL, sc->reclaim_idx, 1);
 
 	do {
 		vmpressure_prio(sc->gfp_mask, sc->target_mem_cgroup,
diff --git a/mm/vmstat.c b/mm/vmstat.c
index ab7f78995c89..af070cf5e762 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -983,6 +983,8 @@ const char * const vmstat_text[] = {
 	"pswpout",
 
 	TEXTS_FOR_ZONES("pgalloc")
+	TEXTS_FOR_ZONES("pgstall")
+	TEXTS_FOR_ZONES("pgskip")
 
 	"pgfree",
 	"pgactivate",
@@ -1008,7 +1010,6 @@ const char * const vmstat_text[] = {
 	"kswapd_low_wmark_hit_quickly",
 	"kswapd_high_wmark_hit_quickly",
 	"pageoutrun",
-	"allocstall",
 
 	"pgrotated",
 
-- 
2.6.4

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#1439248 — [PATCH 25/34] mm, vmscan: avoid passing in classzone_idx unnecessarily to compaction_ready

FromMel Gorman <mgorman@techsingularity.net>
Date2016-07-08 11:50 +0200
Subject[PATCH 25/34] mm, vmscan: avoid passing in classzone_idx unnecessarily to compaction_ready
Message-ID<rSAA1-2Xn-21@gated-at.bofh.it>
In reply to#1439225
The scan_control structure has enough information available for
compaction_ready() to make a decision. The classzone_idx manipulations in
shrink_zones() are no longer necessary as the highest populated zone is
no longer used to determine if shrink_slab should be called or not.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
---
 mm/vmscan.c | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index bba71b6c9a4c..6d5c78e2312b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2521,7 +2521,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
  * Returns true if compaction should go ahead for a high-order request, or
  * the high-order allocation would succeed without compaction.
  */
-static inline bool compaction_ready(struct zone *zone, int order, int classzone_idx)
+static inline bool compaction_ready(struct zone *zone, struct scan_control *sc)
 {
 	unsigned long watermark;
 	bool watermark_ok;
@@ -2532,21 +2532,21 @@ static inline bool compaction_ready(struct zone *zone, int order, int classzone_
 	 * there is a buffer of free pages available to give compaction
 	 * a reasonable chance of completing and allocating the page
 	 */
-	watermark = high_wmark_pages(zone) + (2UL << order);
-	watermark_ok = zone_watermark_ok_safe(zone, 0, watermark, classzone_idx);
+	watermark = high_wmark_pages(zone) + (2UL << sc->order);
+	watermark_ok = zone_watermark_ok_safe(zone, 0, watermark, sc->reclaim_idx);
 
 	/*
 	 * If compaction is deferred, reclaim up to a point where
 	 * compaction will have a chance of success when re-enabled
 	 */
-	if (compaction_deferred(zone, order))
+	if (compaction_deferred(zone, sc->order))
 		return watermark_ok;
 
 	/*
 	 * If compaction is not ready to start and allocation is not likely
 	 * to succeed without it, then keep reclaiming.
 	 */
-	if (compaction_suitable(zone, order, 0, classzone_idx) == COMPACT_SKIPPED)
+	if (compaction_suitable(zone, sc->order, 0, sc->reclaim_idx) == COMPACT_SKIPPED)
 		return false;
 
 	return watermark_ok;
@@ -2567,7 +2567,6 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 	unsigned long nr_soft_reclaimed;
 	unsigned long nr_soft_scanned;
 	gfp_t orig_mask;
-	enum zone_type classzone_idx;
 	pg_data_t *last_pgdat = NULL;
 
 	/*
@@ -2578,7 +2577,7 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 	orig_mask = sc->gfp_mask;
 	if (buffer_heads_over_limit) {
 		sc->gfp_mask |= __GFP_HIGHMEM;
-		sc->reclaim_idx = classzone_idx = gfp_zone(sc->gfp_mask);
+		sc->reclaim_idx = gfp_zone(sc->gfp_mask);
 	}
 
 	for_each_zone_zonelist_nodemask(zone, z, zonelist,
@@ -2587,17 +2586,6 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 			continue;
 
 		/*
-		 * Note that reclaim_idx does not change as it is the highest
-		 * zone reclaimed from which for empty zones is a no-op but
-		 * classzone_idx is used by shrink_node to test if the slabs
-		 * should be shrunk on a given node.
-		 */
-		classzone_idx = sc->reclaim_idx;
-		while (!populated_zone(zone->zone_pgdat->node_zones +
-							classzone_idx))
-			classzone_idx--;
-
-		/*
 		 * Take care memory controller reclaiming has small influence
 		 * to global LRU.
 		 */
@@ -2621,8 +2609,8 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 			 */
 			if (IS_ENABLED(CONFIG_COMPACTION) &&
 			    sc->order > PAGE_ALLOC_COSTLY_ORDER &&
-			    zonelist_zone_idx(z) <= classzone_idx &&
-			    compaction_ready(zone, sc->order, classzone_idx)) {
+			    zonelist_zone_idx(z) <= sc->reclaim_idx &&
+			    compaction_ready(zone, sc)) {
 				sc->compaction_ready = true;
 				continue;
 			}
-- 
2.6.4

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