From: Michal Hocko <mhocko@kernel.org>
To: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] radix-tree: account nodes to memcg only if explicitly requested
Date: Tue, 2 Aug 2016 14:46:45 +0200 [thread overview]
Message-ID: <20160802124644.GL12403@dhcp22.suse.cz> (raw)
In-Reply-To: <20160802124220.GC13263@esperanza>
On Tue 02-08-16 15:42:20, Vladimir Davydov wrote:
> On Tue, Aug 02, 2016 at 01:51:12PM +0200, Michal Hocko wrote:
> > On Mon 01-08-16 16:13:08, Vladimir Davydov wrote:
> > > Radix trees may be used not only for storing page cache pages, so
> > > unconditionally accounting radix tree nodes to the current memory cgroup
> > > is bad: if a radix tree node is used for storing data shared among
> > > different cgroups we risk pinning dead memory cgroups forever. So let's
> > > only account radix tree nodes if it was explicitly requested by passing
> > > __GFP_ACCOUNT to INIT_RADIX_TREE. Currently, we only want to account
> > > page cache entries, so mark mapping->page_tree so.
> > >
> > > Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
> >
> > OK, the patch makes sense to me. Such a false sharing would be really
> > tedious to debug
> >
> > Do we want to mark it for stable 4.6 to prevent from some pathological
> > issues. The patch is simple enough.
>
> Makes sense, expecially taking into account that kmemcg is enabled by
> default now.
>
> I'll resend the patch for stable then.
Maybe Andrew just want's to mark it for stable with
Fixes: 58e698af4c63 ("radix-tree: account radix_tree_node to memory cgroup")
Cc: stable # 4.6
> > Acked-by: Michal Hocko <mhocko@suse.com>
>
> Thanks!
>
> --
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--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-08-02 12:46 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-01 13:13 [PATCH] radix-tree: account nodes to memcg only if explicitly requested Vladimir Davydov
2016-08-01 15:24 ` Johannes Weiner
2016-08-01 16:06 ` Vladimir Davydov
2016-08-01 17:14 ` Johannes Weiner
2016-08-02 11:51 ` Michal Hocko
2016-08-02 12:42 ` Vladimir Davydov
2016-08-02 12:46 ` Michal Hocko [this message]
2016-08-02 18:51 ` Andrew Morton
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