Subject: + memcg-fix-multiple-large-threshold-notifications.patch added to -mm
tree
To:
[email protected],[email protected],[email protected],[email protected],[email protected]
From: [email protected]
Date: Tue, 10 Sep 2013 17:04:26 -0700
The patch titled
Subject: memcg: fix multiple large threshold notifications
has been added to the -mm tree. Its filename is
memcg-fix-multiple-large-threshold-notifications.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/memcg-fix-multiple-large-threshold-notifications.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/memcg-fix-multiple-large-threshold-notifications.patch
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From: Greg Thelen <[email protected]>
Subject: memcg: fix multiple large threshold notifications
A memory cgroup with (1) multiple threshold notifications and (2) at least
one threshold >=2G was not reliable. Specifically the notifications would
either not fire or would not fire in the proper order.
The __mem_cgroup_threshold() signaling logic depends on keeping 64 bit
thresholds in sorted order. mem_cgroup_usage_register_event() sorts them
with compare_thresholds(), which returns the difference of two 64 bit
thresholds as an int. If the difference is positive but has bit[31] set,
then sort() treats the difference as negative and breaks sort order.
This fix compares the two arbitrary 64 bit thresholds returning the
classic -1, 0, 1 result.
The test below sets two notifications (at 0x1000 and 0x81001000):
cd /sys/fs/cgroup/memory
mkdir x
for x in 4096 2164264960; do
cgroup_event_listener x/memory.usage_in_bytes $x | sed "s/^/$x listener:/" &
done
echo $$ > x/cgroup.procs
anon_leaker 500M
v3.11-rc7 fails to signal the 4096 event listener:
Leaking...
Done leaking pages.
Patched v3.11-rc7 properly notifies:
Leaking...
4096 listener:2013:8:31:14:13:36
Done leaking pages.
The fixed bug is old. It appears to date back to the introduction of
memcg threshold notifications in v2.6.34-rc1-116-g2e72b6347c94 "memcg:
implement memory thresholds"
Signed-off-by: Greg Thelen <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
mm/memcontrol.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff -puN mm/memcontrol.c~memcg-fix-multiple-large-threshold-notifications
mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-fix-multiple-large-threshold-notifications
+++ a/mm/memcontrol.c
@@ -5591,7 +5591,13 @@ static int compare_thresholds(const void
const struct mem_cgroup_threshold *_a = a;
const struct mem_cgroup_threshold *_b = b;
- return _a->threshold - _b->threshold;
+ if (_a->threshold > _b->threshold)
+ return 1;
+
+ if (_a->threshold < _b->threshold)
+ return -1;
+
+ return 0;
}
static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
_
Patches currently in -mm which might be from [email protected] are
memcg-fix-multiple-large-threshold-notifications.patch
memcg-vmscan-integrate-soft-reclaim-tighter-with-zone-shrinking-code.patch
memcg-get-rid-of-soft-limit-tree-infrastructure.patch
vmscan-memcg-do-softlimit-reclaim-also-for-targeted-reclaim.patch
memcg-enhance-memcg-iterator-to-support-predicates.patch
memcg-track-children-in-soft-limit-excess-to-improve-soft-limit.patch
memcg-vmscan-do-not-attempt-soft-limit-reclaim-if-it-would-not-scan-anything.patch
memcg-track-all-children-over-limit-in-the-root.patch
memcg-vmscan-do-not-fall-into-reclaim-all-pass-too-quickly.patch
memcg-remove-memcg_nr_file_mapped.patch
memcg-check-for-proper-lock-held-in-mem_cgroup_update_page_stat.patch
memcg-add-per-cgroup-writeback-pages-accounting.patch
memcg-document-cgroup-dirty-writeback-memory-statistics.patch
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