From: Andrew Morton <akpm@linux-foundation.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: aryabinin@virtuozzo.com, linux-mm@kvack.org,
kasan-dev@googlegroups.com, Greg Thelen <gthelen@google.com>
Subject: Re: [PATCH] kasan: resched in quarantine_remove_cache()
Date: Wed, 8 Mar 2017 15:05:58 -0800 [thread overview]
Message-ID: <20170308150558.15e44d3f10b4a9f9215b33c8@linux-foundation.org> (raw)
In-Reply-To: <20170308154239.25440-1-dvyukov@google.com>
On Wed, 8 Mar 2017 16:42:39 +0100 Dmitry Vyukov <dvyukov@google.com> wrote:
> We see reported stalls/lockups in quarantine_remove_cache() on machines
> with large amounts of RAM. quarantine_remove_cache() needs to scan whole
> quarantine in order to take out all objects belonging to the cache.
> Quarantine is currently 1/32-th of RAM, e.g. on a machine with 256GB
> of memory that will be 8GB. Moreover quarantine scanning is a walk
> over uncached linked list, which is slow.
>
> Add cond_resched() after scanning of each non-empty batch of objects.
> Batches are specifically kept of reasonable size for quarantine_put().
> On a machine with 256GB of RAM we should have ~512 non-empty batches,
> each with 16MB of objects.
I'll add cc:stable to this one - softlockup reports on large machines
is a pretty significant issue.
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next prev parent reply other threads:[~2017-03-08 23:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-08 15:42 [PATCH] kasan: resched in quarantine_remove_cache() Dmitry Vyukov
2017-03-08 23:05 ` Andrew Morton [this message]
2017-03-09 8:37 ` Andrey Ryabinin
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