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>
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 25c679e..f52481b 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -356,7 +356,8 @@
} while_each_thread(g, p);
}
-static void dump_header(gfp_t gfp_mask, int order, struct mem_cgroup *mem)
+static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
+ struct mem_cgroup *mem)
{
pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
"oom_adj=%d\n",
@@ -365,7 +366,7 @@
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);
@@ -440,7 +441,7 @@
struct task_struct *c;
if (printk_ratelimit())
- dump_header(gfp_mask, order, mem);
+ dump_header(p, gfp_mask, order, mem);
/*
* If the task is already exiting, don't alarm the sysadmin or kill
@@ -576,7 +577,7 @@
/* Found nothing?!?! Either we hang forever, or we panic. */
if (!p) {
read_unlock(&tasklist_lock);
- dump_header(gfp_mask, order, NULL);
+ dump_header(NULL, gfp_mask, order, NULL);
panic("Out of memory and no killable processes...\n");
}
@@ -644,7 +645,7 @@
return;
if (sysctl_panic_on_oom == 2) {
- dump_header(gfp_mask, order, NULL);
+ dump_header(NULL, gfp_mask, order, NULL);
panic("out of memory. Compulsory panic_on_oom is selected.\n");
}
@@ -663,7 +664,7 @@
case CONSTRAINT_NONE:
if (sysctl_panic_on_oom) {
- dump_header(gfp_mask, order, NULL);
+ dump_header(NULL, gfp_mask, order, NULL);
panic("out of memory. panic_on_oom is selected\n");
}
/* Fall-through */