From: Roman Gushchin <guro@fb.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Muchun Song <songmuchun@bytedance.com>,
Shakeel Butt <shakeelb@google.com>,
Michal Hocko <mhocko@suse.com>, <linux-mm@kvack.org>,
<cgroups@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<kernel-team@fb.com>
Subject: Re: [PATCH] fs: buffer: use raw page_memcg() on locked page
Date: Tue, 9 Feb 2021 11:20:01 -0800 [thread overview]
Message-ID: <20210209192001.GA524633@carbon.DHCP.thefacebook.com> (raw)
In-Reply-To: <20210209190126.97842-1-hannes@cmpxchg.org>
On Tue, Feb 09, 2021 at 02:01:26PM -0500, Johannes Weiner wrote:
> alloc_page_buffers() currently uses get_mem_cgroup_from_page() for
> charging the buffers to the page owner, which does an rcu-protected
> page->memcg lookup and acquires a reference. But buffer allocation has
> the page lock held throughout, which pins the page to the memcg and
> thereby the memcg - neither rcu nor holding an extra reference during
> the allocation are necessary. Use a raw page_memcg() instead.
>
> This was the last user of get_mem_cgroup_from_page(), delete it.
>
> Reported-by: Muchun Song <songmuchun@bytedance.com>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <guro@fb.com>
Thanks!
next prev parent reply other threads:[~2021-02-09 23:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 19:01 [PATCH] fs: buffer: use raw page_memcg() on locked page Johannes Weiner
2021-02-09 19:12 ` Shakeel Butt
2021-02-09 19:20 ` Roman Gushchin [this message]
2021-02-10 9:18 ` Michal Hocko
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