This is a note to let you know that I've just added the patch titled
mm: fix negative nr_isolated counts
to the 3.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-fix-negative-nr_isolated-counts.patch
and it can be found in the queue-3.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ff59909a077b3c51c168cb658601c6b63136a347 Mon Sep 17 00:00:00 2001
From: Hugh Dickins <hughd@xxxxxxxxxx>
Date: Thu, 12 Feb 2015 15:00:28 -0800
Subject: mm: fix negative nr_isolated counts
From: Hugh Dickins <hughd@xxxxxxxxxx>
commit ff59909a077b3c51c168cb658601c6b63136a347 upstream.
The vmstat interfaces are good at hiding negative counts (at least when
CONFIG_SMP); but if you peer behind the curtain, you find that
nr_isolated_anon and nr_isolated_file soon go negative, and grow ever
more negative: so they can absorb larger and larger numbers of isolated
pages, yet still appear to be zero.
I'm happy to avoid a congestion_wait() when too_many_isolated() myself;
but I guess it's there for a good reason, in which case we ought to get
too_many_isolated() working again.
The imbalance comes from isolate_migratepages()'s ISOLATE_ABORT case:
putback_movable_pages() decrements the NR_ISOLATED counts, but we forgot
to call acct_isolated() to increment them.
It is possible that the bug whcih this patch fixes could cause OOM kills
when the system still has a lot of reclaimable page cache.
Fixes: edc2ca612496 ("mm, compaction: move pageblock checks up from isolate_migratepages_range()")
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1015,8 +1015,10 @@ static isolate_migrate_t isolate_migrate
low_pfn = isolate_migratepages_block(cc, low_pfn, end_pfn,
isolate_mode);
- if (!low_pfn || cc->contended)
+ if (!low_pfn || cc->contended) {
+ acct_isolated(zone, cc);
return ISOLATE_ABORT;
+ }
/*
* Either we isolated something and proceed with migration. Or
Patches currently in stable-queue which might be from hughd@xxxxxxxxxx are
queue-3.19/mm-fix-negative-nr_isolated-counts.patch
queue-3.19/mm-hugetlb-add-migration-hwpoisoned-entry-check-in-hugetlb_change_protection.patch
queue-3.19/mm-hugetlb-fix-getting-refcount-0-page-in-hugetlb_fault.patch
queue-3.19/mm-hugetlb-add-migration-entry-check-in-__unmap_hugepage_range.patch
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