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| author | Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> | 2009-12-16 03:47:12 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-16 18:20:07 +0300 |
| commit | d31f56dbf8bafaacb0c617f9a6f137498d5c7aed (patch) | |
| tree | 88d095c2208d27362e58ff7431407040ead9d848 /mm/memcontrol.c | |
| parent | 57f9fd7d25ac9a0d7e3a4ced580e780ab4524e3b (diff) | |
| download | linux-d31f56dbf8bafaacb0c617f9a6f137498d5c7aed.tar.xz | |
memcg: avoid oom-killing innocent task in case of use_hierarchy
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>/aa use_hierarchy == 0 <- hitting limit
<some path>/aa/00 use_hierarchy == 1 <- the task belongs to
This leads to killing an innocent task in aa/00. 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: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6273984f2e34..a294b7576070 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -760,7 +760,13 @@ 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); @@ -1009,7 +1015,7 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) static char memcg_name[PATH_MAX]; int ret; - if (!memcg) + if (!memcg || !p) return; |