The patch titled memcg: handle panic_on_oom=always case has been added to the -mm tree. Its filename is memcg-handle-panic_on_oom=always-case-v2.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 *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: memcg: handle panic_on_oom=always case From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Presently, if panic_on_oom=2, the whole system panics even if the oom happend in some special situation (as cpuset, mempolicy....). Then, panic_on_oom=2 means painc_on_oom_always. Now, memcg doesn't check panic_on_oom flag. This patch adds a check. BTW, how it's useful ? kdump+panic_on_oom=2 is the last tool to investigate what happens in oom-ed system. When a task is killed, the sysytem recovers and there will be few hint to know what happnes. In mission critical system, oom should never happen. Then, panic_on_oom=2+kdump is useful to avoid next OOM by knowing precise information via snapshot. TODO: - For memcg, it's for isolate system's memory usage, oom-notiifer and freeze_at_oom (or rest_at_oom) should be implemented. Then, management daemon can do similar jobs (as kdump) or taking snapshot per cgroup. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Nick Piggin <npiggin@xxxxxxx> Reviewed-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/cgroups/memory.txt | 5 ++++- Documentation/sysctl/vm.txt | 5 ++++- mm/oom_kill.c | 2 ++ 3 files changed, 10 insertions(+), 2 deletions(-) diff -puN Documentation/cgroups/memory.txt~memcg-handle-panic_on_oom=always-case-v2 Documentation/cgroups/memory.txt --- a/Documentation/cgroups/memory.txt~memcg-handle-panic_on_oom=always-case-v2 +++ a/Documentation/cgroups/memory.txt @@ -182,6 +182,8 @@ list. NOTE: Reclaim does not work for the root cgroup, since we cannot set any limits on the root cgroup. +Note2: When panic_on_oom is set to "2", the whole system will panic. + 2. Locking The memory controller uses the following hierarchy @@ -379,7 +381,8 @@ The feature can be disabled by NOTE1: Enabling/disabling will fail if the cgroup already has other cgroups created below it. -NOTE2: This feature can be enabled/disabled per subtree. +NOTE2: When panic_on_oom is set to "2", the whole system will panic in +case of an oom event in any cgroup. 7. Soft limits diff -puN Documentation/sysctl/vm.txt~memcg-handle-panic_on_oom=always-case-v2 Documentation/sysctl/vm.txt --- a/Documentation/sysctl/vm.txt~memcg-handle-panic_on_oom=always-case-v2 +++ a/Documentation/sysctl/vm.txt @@ -573,11 +573,14 @@ Because other nodes' memory may be free. may be not fatal yet. If this is set to 2, the kernel panics compulsorily even on the -above-mentioned. +above-mentioned. Even oom happens under memory cgroup, the whole +system panics. The default value is 0. 1 and 2 are for failover of clustering. Please select either according to your policy of failover. +panic_on_oom=2+kdump gives you very strong tool to investigate +why oom happens. You can get snapshot. ============================================================= diff -puN mm/oom_kill.c~memcg-handle-panic_on_oom=always-case-v2 mm/oom_kill.c --- a/mm/oom_kill.c~memcg-handle-panic_on_oom=always-case-v2 +++ a/mm/oom_kill.c @@ -473,6 +473,8 @@ void mem_cgroup_out_of_memory(struct mem unsigned long points = 0; struct task_struct *p; + if (sysctl_panic_on_oom == 2) + panic("out of memory(memcg). panic_on_oom is selected.\n"); read_lock(&tasklist_lock); retry: p = select_bad_process(&points, mem); _ Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are memcg-fix-oom-killing-a-child-process-in-an-other-cgroup.patch linux-next.patch vfs-introduce-fmode_neg_offset-for-allowing-negative-f_pos.patch mm-clean-up-mm_counter.patch mm-avoid-false-sharing-of-mm_counter.patch mm-avoid-false-sharing-of-mm_counter-checkpatch-fixes.patch mm-count-swap-usage.patch mm-count-swap-usage-checkpatch-fixes.patch vmscan-get_scan_ratio-cleanup.patch mm-restore-zone-all_unreclaimable-to-independence-word.patch mm-restore-zone-all_unreclaimable-to-independence-word-fix.patch mm-restore-zone-all_unreclaimable-to-independence-word-fix-2.patch mm-migratec-kill-anon-local-variable-from-migrate_page_copy.patch nodemaskh-remove-macro-any_online_node.patch devmem-dont-allow-seek-to-last-page.patch drivers-char-memc-cleanups.patch drivers-char-memc-cleanups-fix.patch drivers-char-memc-cleanups-fix-fix.patch cgroup-introduce-cancel_attach.patch cgroup-introduce-coalesce-css_get-and-css_put.patch cgroups-revamp-subsys-array.patch cgroups-subsystem-module-loading-interface.patch cgroups-subsystem-module-loading-interface-fix.patch cgroups-subsystem-module-unloading.patch cgroups-net_cls-as-module.patch cgroups-blkio-subsystem-as-module.patch cgroups-clean-up-cgroup_pidlist_find-a-bit.patch memcg-add-interface-to-move-charge-at-task-migration.patch memcg-move-charges-of-anonymous-page.patch memcg-move-charges-of-anonymous-page-cleanup.patch memcg-improve-performance-in-moving-charge.patch memcg-avoid-oom-during-moving-charge.patch memcg-move-charges-of-anonymous-swap.patch memcg-move-charges-of-anonymous-swap-fix.patch memcg-improve-performance-in-moving-swap-charge.patch memcg-improve-performance-in-moving-swap-charge-fix.patch cgroup-implement-eventfd-based-generic-api-for-notifications.patch cgroup-implement-eventfd-based-generic-api-for-notifications-kconfig-fix.patch cgroup-implement-eventfd-based-generic-api-for-notifications-fixes.patch memcg-extract-mem_group_usage-from-mem_cgroup_read.patch memcg-rework-usage-of-stats-by-soft-limit.patch memcg-implement-memory-thresholds.patch memcg-implement-memory-thresholds-checkpatch-fixes.patch memcg-implement-memory-thresholds-checkpatch-fixes-fix.patch memcg-implement-memory-thresholds-check-if-first-threshold-crossed.patch memcg-typo-in-comment-to-mem_cgroup_print_oom_info.patch memcg-use-generic-percpu-instead-of-private-implementation.patch memcg-update-threshold-and-softlimit-at-commit-v2.patch memcg-share-event-counter-rather-than-duplicate-v2.patch memcg-update-memcg_testtxt.patch memcg-handle-panic_on_oom=always-case-v2.patch sysctl-clean-up-vm-related-variable-declarations.patch sysctl-clean-up-vm-related-variable-declarations-fix.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html