The patch titled memcg: fix OOM killer under memcg has been added to the -mm tree. Its filename is memcg-fix-oom-killer-under-memcg.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: fix OOM killer under memcg From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> This patch tries to fix OOM Killer problems caused by hierarchy. Now, memcg itself has OOM KILL function (in oom_kill.c) and tries to kill a task in memcg. But, when hierarchy is used, it's broken and correct task cannot be killed. For example, in following cgroup /groupA/ hierarchy=1, limit=1G, 01 nolimit 02 nolimit All tasks' memory usage under /groupA, /groupA/01, groupA/02 is limited to groupA's 1Gbytes but OOM Killer just kills tasks in groupA. This patch provides makes the bad process be selected from all tasks under hierarchy. BTW, currently, oom_jiffies is updated against groupA in above case. oom_jiffies of tree should be updated. To see how oom_jiffies is used, please check mem_cgroup_oom_called() callers. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Paul Menage <menage@xxxxxxxxxx> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx> Cc: Balbir Singh <balbir@xxxxxxxxxx> Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/cgroups/memcg_test.txt | 20 ++++++++++++++- include/linux/memcontrol.h | 4 +-- mm/memcontrol.c | 32 ++++++++++++++++++++++--- 3 files changed, 50 insertions(+), 6 deletions(-) diff -puN Documentation/cgroups/memcg_test.txt~memcg-fix-oom-killer-under-memcg Documentation/cgroups/memcg_test.txt --- a/Documentation/cgroups/memcg_test.txt~memcg-fix-oom-killer-under-memcg +++ a/Documentation/cgroups/memcg_test.txt @@ -1,5 +1,5 @@ Memory Resource Controller(Memcg) Implementation Memo. -Last Updated: 2009/1/19 +Last Updated: 2009/1/20 Base Kernel Version: based on 2.6.29-rc2. Because VM is getting complex (one of reasons is memcg...), memcg's behavior @@ -360,3 +360,21 @@ Under below explanation, we assume CONFI # kill malloc task. Of course, tmpfs v.s. swapoff test should be tested, too. + + 9.8 OOM-Killer + Out-of-memory caused by memcg's limit will kill tasks under + the memcg. When hierarchy is used, a task under hierarchy + will be killed by the kernel. + In this case, panic_on_oom shouldn't be invoked and tasks + in other groups shouldn't be killed. + + It's not difficult to cause OOM under memcg as following. + Case A) when you can swapoff + #swapoff -a + #echo 50M > /memory.limit_in_bytes + run 51M of malloc + + Case B) when you use mem+swap limitation. + #echo 50M > memory.limit_in_bytes + #echo 50M > memory.memsw.limit_in_bytes + run 51M of malloc diff -puN include/linux/memcontrol.h~memcg-fix-oom-killer-under-memcg include/linux/memcontrol.h --- a/include/linux/memcontrol.h~memcg-fix-oom-killer-under-memcg +++ a/include/linux/memcontrol.h @@ -66,7 +66,7 @@ extern unsigned long mem_cgroup_isolate_ struct mem_cgroup *mem_cont, int active, int file); extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask); -int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem); +int task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *mem); extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p); @@ -192,7 +192,7 @@ static inline int mm_match_cgroup(struct } static inline int task_in_mem_cgroup(struct task_struct *task, - const struct mem_cgroup *mem) + struct mem_cgroup *mem) { return 1; } diff -puN mm/memcontrol.c~memcg-fix-oom-killer-under-memcg mm/memcontrol.c --- a/mm/memcontrol.c~memcg-fix-oom-killer-under-memcg +++ a/mm/memcontrol.c @@ -295,6 +295,9 @@ struct mem_cgroup *mem_cgroup_from_task( static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) { struct mem_cgroup *mem = NULL; + + if (!mm) + return; /* * Because we have no locks, mm->owner's may be being moved to other * cgroup. We use css_tryget() here even if this looks @@ -483,13 +486,23 @@ void mem_cgroup_move_lists(struct page * mem_cgroup_add_lru_list(page, to); } -int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) +int task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *mem) { int ret; + struct mem_cgroup *curr = NULL; task_lock(task); - ret = task->mm && mm_match_cgroup(task->mm, mem); + rcu_read_lock(); + curr = try_get_mem_cgroup_from_mm(task->mm); + rcu_read_unlock(); task_unlock(task); + if (!curr) + return 0; + if (curr->use_hierarchy) + ret = css_is_ancestor(&curr->css, &mem->css); + else + ret = (curr == mem); + css_put(&curr->css); return ret; } @@ -820,6 +833,19 @@ bool mem_cgroup_oom_called(struct task_s rcu_read_unlock(); return ret; } + +static int record_last_oom_cb(struct mem_cgroup *mem, void *data) +{ + mem->last_oom_jiffies = jiffies; + return 0; +} + +static void record_last_oom(struct mem_cgroup *mem) +{ + mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb); +} + + /* * Unlike exported interface, "oom" parameter is added. if oom==true, * oom-killer can be invoked. @@ -902,7 +928,7 @@ static int __mem_cgroup_try_charge(struc mutex_lock(&memcg_tasklist); mem_cgroup_out_of_memory(mem_over_limit, gfp_mask); mutex_unlock(&memcg_tasklist); - mem_over_limit->last_oom_jiffies = jiffies; + record_last_oom(mem_over_limit); } goto nomem; } _ Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are origin.patch proc-pid-maps-dont-show-pgoff-of-pure-anon-vmas.patch proc-pid-maps-dont-show-pgoff-of-pure-anon-vmas-checkpatch-fixes.patch cgroup-css-id-support.patch cgroup-fix-frequent-ebusy-at-rmdir.patch memcg-use-css-id.patch memcg-hierarchical-stat.patch memcg-fix-shrinking-memory-to-return-ebusy-by-fixing-retry-algorithm.patch memcg-fix-oom-killer-under-memcg.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