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Groups > linux.kernel > #1458157
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 4.6 14/96] mm, compaction: prevent VM_BUG_ON when terminating freeing scanner |
| Date | 2016-08-08 21:50 +0200 |
| Message-ID | <s3YIG-5FD-3@gated-at.bofh.it> (permalink) |
| References | <s3YfD-5sp-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
4.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: David Rientjes <rientjes@google.com>
commit a46cbf3bc53b6a93fb84a5ffb288c354fa807954 upstream.
It's possible to isolate some freepages in a pageblock and then fail
split_free_page() due to the low watermark check. In this case, we hit
VM_BUG_ON() because the freeing scanner terminated early without a
contended lock or enough freepages.
This should never have been a VM_BUG_ON() since it's not a fatal
condition. It should have been a VM_WARN_ON() at best, or even handled
gracefully.
Regardless, we need to terminate anytime the full pageblock scan was not
done. The logic belongs in isolate_freepages_block(), so handle its
state gracefully by terminating the pageblock loop and making a note to
restart at the same pageblock next time since it was not possible to
complete the scan this time.
[rientjes@google.com: don't rescan pages in a pageblock]
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1607111244150.83138@chino.kir.corp.google.com
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1606291436300.145590@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Minchan Kim <minchan@kernel.org>
Tested-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
mm/compaction.c | 36 ++++++++++++++----------------------
1 file changed, 14 insertions(+), 22 deletions(-)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -936,8 +936,6 @@ static void isolate_freepages(struct com
block_end_pfn = block_start_pfn,
block_start_pfn -= pageblock_nr_pages,
isolate_start_pfn = block_start_pfn) {
- unsigned long isolated;
-
/*
* This can iterate a massively long zone without finding any
* suitable migration targets, so periodically check if we need
@@ -961,36 +959,30 @@ static void isolate_freepages(struct com
continue;
/* Found a block suitable for isolating free pages from. */
- isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, freelist, false);
- /* If isolation failed early, do not continue needlessly */
- if (!isolated && isolate_start_pfn < block_end_pfn &&
- cc->nr_migratepages > cc->nr_freepages)
- break;
+ isolate_freepages_block(cc, &isolate_start_pfn, block_end_pfn,
+ freelist, false);
/*
- * If we isolated enough freepages, or aborted due to async
- * compaction being contended, terminate the loop.
- * Remember where the free scanner should restart next time,
- * which is where isolate_freepages_block() left off.
- * But if it scanned the whole pageblock, isolate_start_pfn
- * now points at block_end_pfn, which is the start of the next
- * pageblock.
- * In that case we will however want to restart at the start
- * of the previous pageblock.
+ * If we isolated enough freepages, or aborted due to lock
+ * contention, terminate.
*/
if ((cc->nr_freepages >= cc->nr_migratepages)
|| cc->contended) {
- if (isolate_start_pfn >= block_end_pfn)
+ if (isolate_start_pfn >= block_end_pfn) {
+ /*
+ * Restart at previous pageblock if more
+ * freepages can be isolated next time.
+ */
isolate_start_pfn =
block_start_pfn - pageblock_nr_pages;
+ }
break;
- } else {
+ } else if (isolate_start_pfn < block_end_pfn) {
/*
- * isolate_freepages_block() should not terminate
- * prematurely unless contended, or isolated enough
+ * If isolation failed early, do not continue
+ * needlessly.
*/
- VM_BUG_ON(isolate_start_pfn < block_end_pfn);
+ break;
}
}
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[PATCH 4.6 00/96] 4.6.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 06/96] dmaengine: at_xdmac: fix residue corruption Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 25/96] arc: unwind: warn only once if DW2_UNWIND is disabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 48/96] cgroup: remove redundant cleanup in css_create Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 47/96] pinctrl: imx: Do not treat a PIN without MUX register as an error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 31/96] xen-blkfront: fix resume issues after a migration Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 57/96] cpufreq: Avoid false-positive WARN_ON()s in cpufreq_update_policy() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 37/96] Input: elantech - add more IC body types to the list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 08/96] mm, sl[au]b: add __GFP_ATOMIC to the GFP reclaim mask Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 52/96] locks: use file_inode() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 30/96] xenbus: dont bail early from xenbus_dev_request_and_reply() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:40 +0200
[PATCH 4.6 21/96] radix-tree: fix radix_tree_iter_retry() for tagged iterators. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:50 +0200
[PATCH 4.6 14/96] mm, compaction: prevent VM_BUG_ON when terminating freeing scanner Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:50 +0200
[PATCH 4.6 18/96] vmlinux.lds: account for destructor sections Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:50 +0200
[PATCH 4.6 22/96] pps: do not crash when failed to register Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:50 +0200
[PATCH 4.6 02/96] x86/quirks: Apply nvidia_bugs quirk only on root bus Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:50 +0200
[PATCH 4.6 16/96] mm, meminit: always return a valid node from early_pfn_to_nid Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:50 +0200
[PATCH 4.6 10/96] memcg: css_alloc should return an ERR_PTR value on error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-08 21:50 +0200
Re: [PATCH 4.6 00/96] 4.6.6-stable review Guenter Roeck <linux@roeck-us.net> - 2016-08-09 07:10 +0200
Re: [PATCH 4.6 00/96] 4.6.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-09 10:30 +0200
Re: [PATCH 4.6 00/96] 4.6.6-stable review Paul Burton <paul.burton@imgtec.com> - 2016-08-09 10:40 +0200
Re: [PATCH 4.6 00/96] 4.6.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-09 10:40 +0200
Re: [PATCH 4.6 00/96] 4.6.6-stable review Guenter Roeck <linux@roeck-us.net> - 2016-08-09 18:20 +0200
Re: [PATCH 4.6 00/96] 4.6.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-09 19:30 +0200
Re: [PATCH 4.6 00/96] 4.6.6-stable review Guenter Roeck <linux@roeck-us.net> - 2016-08-10 03:30 +0200
Re: [PATCH 4.6 00/96] 4.6.6-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-08-09 17:20 +0200
Re: [PATCH 4.6 00/96] 4.6.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-09 19:30 +0200
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