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

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Message-ID: <CAG_fn=V5pTXzPvRGd4PfGp33q8dD7gyNRF8p9W+JXS054Y+RXw@mail.gmail.com>
Date:	Fri, 27 May 2016 19:41:37 +0200
From:	Alexander Potapenko <glider@...gle.com>
To:	Christoph Lameter <cl@...ux.com>
Cc:	Andrey Konovalov <adech.fo@...il.com>,
	Dmitriy Vyukov <dvyukov@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Joonsoo Kim <js1304@...il.com>,
	Kostya Serebryany <kcc@...gle.com>,
	Andrey Ryabinin <aryabinin@...tuozzo.com>,
	kasan-dev <kasan-dev@...glegroups.com>,
	Linux Memory Management List <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] [mm] Set page->slab_cache for every page allocated for
 a kmem_cache.

On Fri, May 27, 2016 at 7:30 PM, Christoph Lameter <cl@...ux.com> wrote:
> 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.
>

Got it, thank you.
Looks like I just need to make sure my code uses
virt_to_head_page()->page_slab to get the cache for an object.

-- 
Alexander Potapenko
Software Engineer

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