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Groups > linux.kernel > #1435467
| From | Mel Gorman <mgorman@techsingularity.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 29/31] mm: vmstat: account per-zone stalls and pages skipped during reclaim |
| Date | 2016-07-01 17:50 +0200 |
| Message-ID | <rQ8RB-8qk-65@gated-at.bofh.it> (permalink) |
| References | <rQ8HU-8mD-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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.
Link: http://lkml.kernel.org/r/1466518566-30034-28-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
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 a687cfa91166..151c30dd27e2 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));
@@ -2676,7 +2687,7 @@ 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 905ea9ae2d5a..b9a9844e3142 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -970,6 +970,8 @@ const char * const vmstat_text[] = {
"pswpout",
TEXTS_FOR_ZONES("pgalloc")
+ TEXTS_FOR_ZONES("pgstall")
+ TEXTS_FOR_ZONES("pgskip")
"pgfree",
"pgactivate",
@@ -995,7 +997,6 @@ 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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[PATCH 00/31] Move LRU page reclaim from zones to nodes v8 Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:40 +0200
[PATCH 06/31] mm, vmscan: make kswapd reclaim in terms of nodes Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:40 +0200
[PATCH 09/31] mm, vmscan: by default have direct reclaim only shrink once per node Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:40 +0200
[PATCH 10/31] mm, vmscan: remove duplicate logic clearing node congestion and dirty state Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:40 +0200
[PATCH 07/31] mm, vmscan: remove balance gap Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:40 +0200
[PATCH 02/31] mm, vmscan: move lru_lock to the node Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:40 +0200
[PATCH 05/31] mm, vmscan: have kswapd only scan based on the highest requested zone Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:40 +0200
[PATCH 19/31] mm: move vmscan writes and file write accounting to the node Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 17/31] mm: rename NR_ANON_PAGES to NR_ANON_MAPPED Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 30/31] mm, vmstat: print node-based stats in zoneinfo file Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 31/31] mm, vmstat: Remove zone and node double accounting by approximating retries Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 22/31] mm: convert zone_reclaim to node_reclaim Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 26/31] mm, page_alloc: remove fair zone allocation policy Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 28/31] mm: vmstat: replace __count_zone_vm_events with a zone id equivalent Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 21/31] mm, page_alloc: Wake kswapd based on the highest eligible zone Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 20/31] mm, vmscan: only wakeup kswapd once per node for the requested classzone Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 14/31] mm, workingset: make working set detection node-aware Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 18/31] mm: move most file-based accounting to the node Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 23/31] mm, vmscan: Avoid passing in classzone_idx unnecessarily to shrink_node Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 27/31] mm: page_alloc: cache the last node whose dirty limit is reached Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 11/31] mm: vmscan: do not reclaim from kswapd if there is any eligible zone Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 12/31] mm, vmscan: make shrink_node decisions more node-centric Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 15/31] mm, page_alloc: consider dirtyable memory in terms of nodes Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 24/31] mm, vmscan: Avoid passing in classzone_idx unnecessarily to compaction_ready Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 13/31] mm, memcg: move memcg limit enforcement from zones to nodes Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 25/31] mm, vmscan: add classzone information to tracepoints Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 29/31] mm: vmstat: account per-zone stalls and pages skipped during reclaim Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
[PATCH 16/31] mm: move page mapped accounting to the node Mel Gorman <mgorman@techsingularity.net> - 2016-07-01 17:50 +0200
Re: [PATCH 00/31] Move LRU page reclaim from zones to nodes v8 Dave Chinner <david@fromorbit.com> - 2016-07-08 01:30 +0200
Re: [PATCH 00/31] Move LRU page reclaim from zones to nodes v8 Mel Gorman <mgorman@techsingularity.net> - 2016-07-08 12:00 +0200
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