Date: Mon, 7 Nov 2016 14:49:31 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Thomas Garnier <thgarnie@google.com>
Cc: Christoph Lameter <cl@linux.com>, Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>, Greg Thelen <gthelen@google.com>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH v3 1/2] memcg: Prevent memcg caches to be both OFF_SLAB
 & OBJFREELIST_SLAB
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        <20161107141919.fe50cef419918c7a4660f3c2@linux-foundation.org>
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On Mon, 7 Nov 2016 14:32:56 -0800 Thomas Garnier <thgarnie@google.com> wrote:

> On Mon, Nov 7, 2016 at 2:19 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
> > On Mon,  7 Nov 2016 13:11:14 -0800 Thomas Garnier <thgarnie@google.com> wrote:
> >
> >> From: Greg Thelen <gthelen@google.com>
> >>
> >> While testing OBJFREELIST_SLAB integration with pagealloc, we found a
> >> bug where kmem_cache(sys) would be created with both CFLGS_OFF_SLAB &
> >> CFLGS_OBJFREELIST_SLAB.
> >>
> >> The original kmem_cache is created early making OFF_SLAB not possible.
> >> When kmem_cache(sys) is created, OFF_SLAB is possible and if pagealloc
> >> is enabled it will try to enable it first under certain conditions.
> >> Given kmem_cache(sys) reuses the original flag, you can have both flags
> >> at the same time resulting in allocation failures and odd behaviors.
> >
> > Can we please have a better description of the problems which this bug
> > causes?  Without this info it's unclear to me which kernel version(s)
> > need the fix.
> >
> > Given that the bug is 6 months old I'm assuming "not very urgent".
> >
> 
> I will add more details and send another round.

Please simply send the additional changelog text in this thread -
processing an entire v4 patch just for a changelog fiddle is rather
heavyweight.