linux-kernel - Re: [PATCH v4] kmemleak: survive in a low-memory situation

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Message-ID: <20190328150555.GD10283@arrakis.emea.arm.com>
Date:   Thu, 28 Mar 2019 15:05:56 +0000
From:   Catalin Marinas <catalin.marinas@....com>
To:     Qian Cai <cai@....pw>
Cc:     Michal Hocko <mhocko@...nel.org>, akpm@...ux-foundation.org,
        cl@...ux.com, willy@...radead.org, penberg@...nel.org,
        rientjes@...gle.com, iamjoonsoo.kim@....com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] kmemleak: survive in a low-memory situation

On Wed, Mar 27, 2019 at 02:02:27PM -0400, Qian Cai wrote:
> On 3/27/19 1:29 PM, Catalin Marinas wrote:
> > From dc4194539f8191bb754901cea74c86e7960886f8 Mon Sep 17 00:00:00 2001
> > From: Catalin Marinas <catalin.marinas@....com>
> > Date: Wed, 27 Mar 2019 17:20:57 +0000
> > Subject: [PATCH] mm: kmemleak: Add an emergency allocation pool for kmemleak
> >  objects
> > 
> > This patch adds an emergency pool for struct kmemleak_object in case the
> > normal kmem_cache_alloc() fails under the gfp constraints passed by the
> > slab allocation caller. The patch also removes __GFP_NOFAIL which does
> > not play well with other gfp flags (introduced by commit d9570ee3bd1d,
> > "kmemleak: allow to coexist with fault injection").
> > 
> > Suggested-by: Michal Hocko <mhocko@...nel.org>
> > Signed-off-by: Catalin Marinas <catalin.marinas@....com>
> 
> It takes 2 runs of LTP oom01 tests to disable kmemleak.

What configuration are you using (number of CPUs, RAM)? I tried this on
an arm64 guest under kvm with 4 CPUs and 512MB of RAM, together with
fault injection on kmemleak_object cache and running oom01 several times
without any failures.

-- 
Catalin