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References: <20210505154613.17214-1-longman@redhat.com> <20210505154613.17214-2-longman@redhat.com>
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From:   Shakeel Butt <shakeelb@google.com>
Date:   Wed, 5 May 2021 09:09:14 -0700
Message-ID: <CALvZod6AfOiKC3tmnJzgAJEUKwXwS__n8on59qbmHyHG2XAc4w@mail.gmail.com>
Subject: Re: [PATCH v3 1/2] mm: memcg/slab: Properly set up gfp flags for
 objcg pointer array
To:     Waiman Long <longman@redhat.com>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Vlastimil Babka <vbabka@suse.cz>, Roman Gushchin <guro@fb.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Cgroups <cgroups@vger.kernel.org>, Linux MM <linux-mm@kvack.org>
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On Wed, May 5, 2021 at 8:47 AM Waiman Long <longman@redhat.com> wrote:
>
> Since the merging of the new slab memory controller in v5.9, the page
> structure may store a pointer to obj_cgroup pointer array for slab pages.
> Currently, only the __GFP_ACCOUNT bit is masked off. However, the array
> is not readily reclaimable and doesn't need to come from the DMA buffer.
> So those GFP bits should be masked off as well.
>
> Do the flag bit clearing at memcg_alloc_page_obj_cgroups() to make sure
> that it is consistently applied no matter where it is called.
>
> Fixes: 286e04b8ed7a ("mm: memcg/slab: allocate obj_cgroups for non-root slab pages")
> Signed-off-by: Waiman Long <longman@redhat.com>

Reviewed-by: Shakeel Butt <shakeelb@google.com>