Messages in this thread | | | Date | Wed, 25 Nov 2009 09:38:46 +0530 | From | Balbir Singh <> | Subject | Re: [BUGFIX][PATCH -stable] memcg: avoid oom-killing innocent task in case of use_hierarchy |
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* nishimura@mxp.nes.nec.co.jp <nishimura@mxp.nes.nec.co.jp> [2009-11-24 16:28:54]:
> task_in_mem_cgroup(), which is called by select_bad_process() to check whether > a task can be a candidate for being oom-killed from memcg's limit, checks > "curr->use_hierarchy"("curr" is the mem_cgroup the task belongs to). > > But this check return true(it's false positive) when: > > <some path>/00 use_hierarchy == 0 <- hitting limit > <some path>/00/aa use_hierarchy == 1 <- "curr" > > This leads to killing an innocent task in 00/aa. This patch is a fix for this > bug. And this patch also fixes the arg for mem_cgroup_print_oom_info(). We > should print information of mem_cgroup which the task being killed, not current, > belongs to. > > Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> > --- > mm/memcontrol.c | 2 +- > mm/oom_kill.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index fd4529d..3acc226 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -496,7 +496,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) > task_unlock(task); > if (!curr) > return 0; > - if (curr->use_hierarchy) > + if (mem->use_hierarchy) > ret = css_is_ancestor(&curr->css, &mem->css); > else > ret = (curr == mem); > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index a7b2460..ed452e9 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -400,7 +400,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, > cpuset_print_task_mems_allowed(current); > task_unlock(current); > dump_stack(); > - mem_cgroup_print_oom_info(mem, current); > + mem_cgroup_print_oom_info(mem, p); > show_mem(); > if (sysctl_oom_dump_tasks) > dump_tasks(mem); >
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
-- Balbir
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