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Date:   Mon, 11 Oct 2021 09:20:36 +0200 (CEST)
From:   Christoph Lameter <cl@gentwo.de>
To:     Hyeonggon Yoo <42.hyeyoo@gmail.com>
cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH] mm, slub: Use prefetchw instead of prefetch
In-Reply-To: <20211008133602.4963-1-42.hyeyoo@gmail.com>
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References: <20211008133602.4963-1-42.hyeyoo@gmail.com>
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On Fri, 8 Oct 2021, Hyeonggon Yoo wrote:

> It's certain that an object will be not only read, but also
> written after allocation.

get_freepointer is used in multiple code path not only in allocation. It
is for example used when scanning through a freelist.

With this change all objects get needlessly dirtied and the cross cpu
cache contention is increased.