memcg: print cgroup information when system panics due to panic_on_oom
If kernel panics due to oom, caused by a cgroup reaching its limit, when
'compulsory panic_on_oom' is enabled, then we will only see that the OOM
happened because of "compulsory panic_on_oom is enabled" but this doesn't
tell the difference between mempolicy and memcg. And dumping system wide
information is plain wrong and more confusing. This patch provides the
information of the cgroup whose limit triggerred panic
Signed-off-by: Balasubramani Vivekanandan <balasubramani_vivekanandan@mentor.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f227786..c3f09b2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1442,15 +1442,17 @@
struct mem_cgroup *iter;
unsigned int i;
- if (!p)
- return;
-
mutex_lock(&oom_info_lock);
rcu_read_lock();
- pr_info("Task in ");
- pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
- pr_cont(" killed as a result of limit of ");
+ if (p) {
+ pr_info("Task in ");
+ pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
+ pr_cont(" killed as a result of limit of ");
+ } else {
+ pr_info("Memory limit reached of cgroup ");
+ }
+
pr_cont_cgroup_path(memcg->css.cgroup);
pr_cont("\n");
@@ -1537,7 +1539,7 @@
return;
}
- check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
+ check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL, memcg);
totalpages = mem_cgroup_get_limit(memcg) ? : 1;
for_each_mem_cgroup_tree(iter, memcg) {
struct css_task_iter it;