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From: Balbir Singh <bsingharora@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Vladimir Davydov" <vdavydov.dev@gmail.com>,
	"Marek Marczykowski-Górecki" <marmarek@mimuw.edu.pl>,
	linux-mm <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: workingset: fix NULL ptr in count_shadow_nodes
Date: Fri, 2 Dec 2016 08:24:16 +1100	[thread overview]
Message-ID: <CAKTCnzmZ1cwmtg+p3=3rTQJbf12VmFzWJcM+wsAdNN20v1DMDw@mail.gmail.com> (raw)
In-Reply-To: <20161201132156.21450-1-mhocko@kernel.org>

On Fri, Dec 2, 2016 at 12:21 AM, Michal Hocko <mhocko@kernel.org> wrote:
> From: Michal Hocko <mhocko@suse.com>
>
> 0a6b76dd23fa ("mm: workingset: make shadow node shrinker memcg aware")
> has made the workingset shadow nodes shrinker memcg aware. The
> implementation is not correct though because memcg_kmem_enabled() might
> become true while we are doing a global reclaim when the sc->memcg might
> be NULL which is exactly what Marek has seen:
>
<snip>
>
> -       if (memcg_kmem_enabled()) {
> +       if (sc->memcg) {
>                 pages = mem_cgroup_node_nr_lru_pages(sc->memcg, sc->nid,
>                                                      LRU_ALL_FILE);
>         } else {

Acked-by: Balbir Singh <bsingharora@gmail.com>

WARNING: multiple messages have this Message-ID (diff)
From: Balbir Singh <bsingharora@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Vladimir Davydov" <vdavydov.dev@gmail.com>,
	"Marek Marczykowski-Górecki" <marmarek@mimuw.edu.pl>,
	linux-mm <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: workingset: fix NULL ptr in count_shadow_nodes
Date: Fri, 2 Dec 2016 08:24:16 +1100	[thread overview]
Message-ID: <CAKTCnzmZ1cwmtg+p3=3rTQJbf12VmFzWJcM+wsAdNN20v1DMDw@mail.gmail.com> (raw)
In-Reply-To: <20161201132156.21450-1-mhocko@kernel.org>

On Fri, Dec 2, 2016 at 12:21 AM, Michal Hocko <mhocko@kernel.org> wrote:
> From: Michal Hocko <mhocko@suse.com>
>
> 0a6b76dd23fa ("mm: workingset: make shadow node shrinker memcg aware")
> has made the workingset shadow nodes shrinker memcg aware. The
> implementation is not correct though because memcg_kmem_enabled() might
> become true while we are doing a global reclaim when the sc->memcg might
> be NULL which is exactly what Marek has seen:
>
<snip>
>
> -       if (memcg_kmem_enabled()) {
> +       if (sc->memcg) {
>                 pages = mem_cgroup_node_nr_lru_pages(sc->memcg, sc->nid,
>                                                      LRU_ALL_FILE);
>         } else {

Acked-by: Balbir Singh <bsingharora@gmail.com>

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  parent reply	other threads:[~2016-12-01 21:24 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-01 13:21 [PATCH] mm: workingset: fix NULL ptr in count_shadow_nodes Michal Hocko
2016-12-01 13:21 ` Michal Hocko
2016-12-01 13:32 ` Vladimir Davydov
2016-12-01 13:32   ` Vladimir Davydov
2016-12-01 21:07 ` Johannes Weiner
2016-12-01 21:07   ` Johannes Weiner
2016-12-01 21:24 ` Balbir Singh [this message]
2016-12-01 21:24   ` Balbir Singh

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