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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id r185sm875146qke.102.2020.01.29.04.25.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Jan 2020 04:25:39 -0800 (PST) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH] mm/page_counter: fix various data races Date: Wed, 29 Jan 2020 07:25:39 -0500 Message-Id: <2D795DB7-66FE-4F01-872F-F8ACAE9505EF@lca.pw> References: <59f892d0-5fc4-ae32-ce65-5a688d9180c8@I-love.SAKURA.ne.jp> Cc: Dmitry Vyukov , Michal Hocko , akpm@linux-foundation.org, hannes@cmpxchg.org, elver@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org In-Reply-To: <59f892d0-5fc4-ae32-ce65-5a688d9180c8@I-love.SAKURA.ne.jp> To: Tetsuo Handa X-Mailer: iPhone Mail (17C54) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000019, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > On Jan 29, 2020, at 7:13 AM, Tetsuo Handa wrote: >=20 > By the way, can READ_ONCE()/WRITE_ONCE() really solve this warning? > The link above says read/write on the same location ( mm/page_counter.c:12= 9 ). > I don't know how READ_ONCE()/WRITE_ONCE() can solve the race. That looks like a different one where it complains about c->failcnt++. I=E2=80= =99ll send a separate patch for that.=