Subject: + memcg-fix-multiple-large-threshold-notifications.patch added to -mm tree To: gthelen@xxxxxxxxxx,hannes@xxxxxxxxxxx,kirill.shutemov@xxxxxxxxxxxxxxx,mhocko@xxxxxxx,stable@xxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx 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 Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Greg Thelen <gthelen@xxxxxxxxxx> 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 <gthelen@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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 gthelen@xxxxxxxxxx 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 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html