The patch titled oom: prevent possible OOM_DISABLE livelock has been added to the -mm tree. Its filename is oom-prevent-possible-oom_disable-livelock.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: oom: prevent possible OOM_DISABLE livelock From: David Rientjes <rientjes@xxxxxxxxxx> This moves the check for OOM_DISABLE to the badness heuristic while holding task_lock(). Badness scores of 0 are now explicitly prohibited from being oom killed and since the oom_adj value is a characteristic of an mm and not a task, it is no longer necessary to check the oom_adj value for threads sharing the same memory (except when simply issuing SIGKILLs for threads in other thread groups). Cc: Nick Piggin <npiggin@xxxxxxx> Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Cc: Peter Ziljstra <a.p.ziljstra@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/oom_kill.c | 40 ++++++++++------------------------------ 1 file changed, 10 insertions(+), 30 deletions(-) diff -puN mm/oom_kill.c~oom-prevent-possible-oom_disable-livelock mm/oom_kill.c --- a/mm/oom_kill.c~oom-prevent-possible-oom_disable-livelock +++ a/mm/oom_kill.c @@ -67,6 +67,10 @@ unsigned long badness(struct task_struct return 0; } oom_adj = mm->oom_adj; + if (oom_adj == OOM_DISABLE) { + task_unlock(p); + return 0; + } /* * The memory size of the process is the basis for the badness. @@ -253,13 +257,8 @@ static struct task_struct *select_bad_pr *ppoints = ULONG_MAX; } - task_lock(p); - if (p->mm && p->mm->oom_adj == OOM_DISABLE) - continue; - task_unlock(p); - points = badness(p, uptime.tv_sec); - if (points > *ppoints || !chosen) { + if (points > *ppoints) { chosen = p; *ppoints = points; } @@ -352,32 +351,13 @@ static int oom_kill_task(struct task_str struct mm_struct *mm; struct task_struct *g, *q; + task_lock(p); mm = p->mm; - - /* WARNING: mm may not be dereferenced since we did not obtain its - * value from get_task_mm(p). This is OK since all we need to do is - * compare mm to q->mm below. - * - * Furthermore, even if mm contains a non-NULL value, p->mm may - * change to NULL at any time since we do not hold task_lock(p). - * However, this is of no concern to us. - */ - - if (mm == NULL) + if (!mm || mm->oom_adj == OOM_DISABLE) { + task_unlock(p); return 1; - - /* - * Don't kill the process if any threads are set to OOM_DISABLE - */ - do_each_thread(g, q) { - task_lock(q); - if (q->mm == mm && q->mm && q->mm->oom_adj == OOM_DISABLE) { - task_unlock(q); - return 1; - } - task_unlock(q); - } while_each_thread(g, q); - + } + task_unlock(p); __oom_kill_task(p, 1); /* _ Patches currently in -mm which might be from rientjes@xxxxxxxxxx are linux-next.patch cpusets-restructure-the-function-cpuset_update_task_memory_state.patch cpusets-update-tasks-page-slab-spread-flags-in-time.patch cpusetmm-update-tasks-mems_allowed-in-time.patch cpusetmm-update-tasks-mems_allowed-in-time-fix.patch cpusetmm-update-tasks-mems_allowed-in-time-cleanup.patch page-allocator-use-a-pre-calculated-value-instead-of-num_online_nodes-in-fast-paths-do-not-override-definition-of-node_set_online-with-macro.patch mm-setup_per_zone_inactive_ratio-do-not-call-for-int_sqrt-if-not-needed.patch mm-setup_per_zone_inactive_ratio-fix-comment-and-make-it-__init.patch mm-invoke-oom-killer-for-__gfp_nofail.patch oom-fix-possible-oom_dump_tasks-null-pointer.patch oom-move-oom_adj-value-from-task_struct-to-mm_struct.patch oom-prevent-possible-oom_disable-livelock.patch memcg-add-file-based-rss-accounting.patch memcg-add-file-based-rss-accounting-fix-mem_cgroup_update_mapped_file_stat-oops.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