Re: [PATCH 0/2 v8] oom: capture unreclaimable slab info in oom message

From: Yang Shi
Date: Mon Oct 02 2017 - 11:46:48 EST

On 10/2/17 4:20 AM, Michal Hocko wrote:
On Thu 28-09-17 13:36:57, Tetsuo Handa wrote:
On 2017/09/28 6:46, Yang Shi wrote:
Changelog v7 â> v8:
* Adopted Michalâs suggestion to dump unreclaim slab info when unreclaimable slabs amount > total user memory. Not only in oom panic path.

Holding slab_mutex inside dump_unreclaimable_slab() was refrained since V2
because there are


users. If we call dump_unreclaimable_slab() for non OOM panic path, aren't we
introducing a risk of crash (i.e. kernel panic) for regular OOM path?

yes we are
We can try mutex_trylock() from dump_unreclaimable_slab() at best.
But it is still remaining unsafe, isn't it?

using the trylock sounds like a reasonable compromise.

OK, it sounds we reach agreement on trylock. Will solve those comments in v9.