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

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Message-ID: <alpine.DEB.2.20.1708071302310.18681@nuc-kabylake>
Date:   Mon, 7 Aug 2017 13:03:03 -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 Mon, 7 Aug 2017, Laura Abbott wrote:

> > 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?
>
> Yes, that's intentional here. I see the validation as a separate more
> expensive feature. I had a crude patch to do some checks for testing
> and I know Daniel Micay had an out of tree patch to do some checks
> as well.

Ok then this patch does nothing? How does this help?