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identity=mailfrom; envelope-from=""; helo=mx0a-00082601.pphosted.com; client-ip=67.231.145.42 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1612898412-11826 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 > Signed-off-by: Johannes Weiner Acked-by: Roman Gushchin Thanks!