linux-kernel - Re: [PATCH v1] [mm] Set page->slab_cache for every page allocated for a kmem

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Message-ID: <alpine.DEB.2.20.1605271229330.30511@east.gentwo.org>
Date:	Fri, 27 May 2016 12:30:43 -0500 (CDT)
From:	Christoph Lameter <cl@...ux.com>
To:	Alexander Potapenko <glider@...gle.com>
cc:	adech.fo@...il.com, dvyukov@...gle.com, akpm@...ux-foundation.org,
	rostedt@...dmis.org, iamjoonsoo.kim@....com, js1304@...il.com,
	kcc@...gle.com, aryabinin@...tuozzo.com,
	kasan-dev@...glegroups.com, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] [mm] Set page->slab_cache for every page allocated
 for a kmem_cache.

On Fri, 27 May 2016, Alexander Potapenko wrote:

> It's reasonable to rely on the fact that for every page allocated for a
> kmem_cache the |slab_cache| field points to that cache. Without that it's
> hard to figure out which cache does an allocated object belong to.

The flags are set only in the head page of a coumpound page which is used
by SLAB. No need to do this. This would just mean unnecessarily dirtying
struct page cachelines on allocation.