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Fri, 02 Oct 2020 06:27:39 -0700 (PDT) Date: Fri, 2 Oct 2020 09:25:57 -0400 From: Johannes Weiner To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: Roman Gushchin , Andrew Morton , Shakeel Butt , Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@fb.com Subject: Re: [PATCH v4 4/4] mm: convert page kmemcg type to a page memcg flag Message-ID: <20201002132557.GA525590@cmpxchg.org> References: <20201001002710.748166-1-guro@fb.com> <20201001002710.748166-5-guro@fb.com> <20201001170036.GA29848@blackbook> <20201001172713.GA500308@cmpxchg.org> <20201002100350.GC24008@blackbody.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20201002100350.GC24008@blackbody.suse.cz> Content-Transfer-Encoding: quoted-printable 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 Fri, Oct 02, 2020 at 12:03:50PM +0200, Michal Koutn=FD wrote: > On Thu, Oct 01, 2020 at 01:27:13PM -0400, Johannes Weiner wrote: > > I do think there is a bug, though: mem_cgroup_move_account() should > > use WRITE_ONCE() on page->mem_cgroup. > If this were a bug, wouldn't be the proper approach > rcu_assign_pointer()/rcu_dereference() pair? Yes, you're right. I'll double check these code paths and follow up with a patch if necessary.