From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Yang Shi <yang.s@alibaba-inc.com>,
cl@linux.com, penberg@kernel.org, rientjes@google.com,
iamjoonsoo.kim@lge.com, akpm@linux-foundation.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2 v8] oom: capture unreclaimable slab info in oom message
Date: Mon, 2 Oct 2017 13:20:51 +0200 [thread overview]
Message-ID: <20171002112051.uk4gyrtygfgtvp5g@dhcp22.suse.cz> (raw)
In-Reply-To: <fccbce9c-a40e-621f-e9a4-17c327ed84e8@I-love.SAKURA.ne.jp>
On Thu 28-09-17 13:36:57, Tetsuo Handa wrote:
> On 2017/09/28 6:46, Yang Shi wrote:
> > Changelog v7 a??> v8:
> > * Adopted Michala??s 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
>
> mutex_lock(&slab_mutex);
> kmalloc(GFP_KERNEL);
> mutex_unlock(&slab_mutex);
>
> 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.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-10-02 11:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-27 21:46 Yang Shi
2017-09-27 21:46 ` [PATCH 1/2] tools: slabinfo: add "-U" option to show unreclaimable slabs only Yang Shi
2017-09-27 21:46 ` [PATCH 2/2] mm: oom: show unreclaimable slab info when unreclaimable slabs > user memory Yang Shi
2017-10-01 6:19 ` Christopher Lameter
2017-09-28 4:36 ` [PATCH 0/2 v8] oom: capture unreclaimable slab info in oom message Tetsuo Handa
2017-09-28 17:49 ` Yang Shi
2017-09-28 19:57 ` Tetsuo Handa
2017-09-28 20:21 ` Yang Shi
2017-09-28 20:45 ` Tetsuo Handa
2017-09-29 22:15 ` Yang Shi
2017-09-30 11:00 ` Tetsuo Handa
2017-10-02 15:40 ` Yang Shi
2017-10-02 11:20 ` Michal Hocko [this message]
2017-10-02 15:46 ` Yang Shi
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