diff options
| author | Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> | 2010-01-05 12:26:33 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-01-06 14:26:49 -0800 |
| commit | ae3559fa2fe48ab923b52885bba2dca0355428f0 (patch) | |
| tree | 6421e0229dac6f291e41d6bd86047de92a8e6a38 /mm/memcontrol.c | |
| parent | f1850a5783908f6528c305e321119e7aa6641151 (diff) | |
memcg: avoid oom-killing innocent task in case of use_hierarchy
commit d31f56dbf8bafaacb0c617f9a6f137498d5c7aed upstream
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>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index fd4529d86de5..566925e7cdbd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -496,7 +496,13 @@ 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) + /* + * We should check use_hierarchy of "mem" not "curr". Because checking + * use_hierarchy of "curr" here make this function true if hierarchy is + * enabled in "curr" and "curr" is a child of "mem" in *cgroup* + * hierarchy(even if use_hierarchy is disabled in "mem"). + */ + if (mem->use_hierarchy) ret = css_is_ancestor(&curr->css, &mem->css); else ret = (curr == mem); |