linux-kernel - Re: [PATCH] memcg: account security cred as well to kmemcg

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Date:   Thu, 5 Dec 2019 18:16:35 -0500
From:   Chris Down <chris@...isdown.name>
To:     Shakeel Butt <shakeelb@...gle.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Roman Gushchin <guro@...com>, linux-mm@...ck.org,
        Johannes Weiner <hannes@...xchg.org>,
        Michal Hocko <mhocko@...e.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] memcg: account security cred as well to kmemcg

Shakeel Butt writes:
>The cred_jar kmem_cache is already memcg accounted in the current
>kernel but cred->security is not. Account cred->security to kmemcg.
>
>Recently we saw high root slab usage on our production and on further
>inspection, we found a buggy application leaking processes. Though that
>buggy application was contained within its memcg but we observe much
>more system memory overhead, couple of GiBs, during that period. This
>overhead can adversely impact the isolation on the system. One of source
>of high overhead, we found was cred->secuity objects.

Makes sense. I took a look through other cred-related allocations to see if any 
others stood out and this looks like it covers all the relevant cases.  
__alloc_file is the only other one that caught my eye, but SLAB_ACCOUNT is on 
the filp cache already.

Thanks :-)

>Signed-off-by: Shakeel Butt <shakeelb@...gle.com>

Acked-by: Chris Down <chris@...isdown.name>