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Date: Wed, 28 Mar 2018 17:00:46 -0500 (CDT)
From: Christopher Lameter <cl@linux.com>
X-X-Sender: cl@nuc-kabylake
To: Shakeel Butt <shakeelb@google.com>
cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Alexander Potapenko <glider@google.com>,
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        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] slab, slub: skip unnecessary kasan_cache_shutdown()
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On Tue, 27 Mar 2018, Shakeel Butt wrote:

> The kasan quarantine is designed to delay freeing slab objects to catch
> use-after-free. The quarantine can be large (several percent of machine
> memory size). When kmem_caches are deleted related objects are flushed
> from the quarantine but this requires scanning the entire quarantine
> which can be very slow. We have seen the kernel busily working on this
> while holding slab_mutex and badly affecting cache_reaper, slabinfo
> readers and memcg kmem cache creations.

Acked-by: Christoph Lameter <cl@linux.com>