linux-kernel - Re: [RFC][PATCH] mm/slub.c: Allow poisoning to use the fast path

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Message-ID: <alpine.DEB.2.20.1708070936400.17268@nuc-kabylake>
Date:   Mon, 7 Aug 2017 09:37:46 -0500 (CDT)
From:   Christopher Lameter <cl@...ux.com>
To:     Laura Abbott <labbott@...hat.com>
cc:     Pekka Enberg <penberg@...nel.org>,
        David Rientjes <rientjes@...gle.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Kees Cook <keescook@...omium.org>,
        Rik van Riel <riel@...hat.com>
Subject: Re: [RFC][PATCH] mm/slub.c: Allow poisoning to use the fast path

On Fri, 4 Aug 2017, Laura Abbott wrote:

> All slub debug features currently disable the fast path completely.
> Some features such as consistency checks require this to allow taking of
> locks. Poisoning and red zoning don't require this and can safely use
> the per-cpu fast path. Introduce a Kconfig to continue to use the fast
> path when 'fast' debugging options are enabled. The code will
> automatically revert to always using the slow path when 'slow' options
> are enabled.

Ok I see that the objects are initialized with poisoning and redzoning but
I do not see that there is fastpath code to actually check the values
before the object is reinitialized. Is that intentional or am
I missing something?