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[134.134.136.24]) by mx.google.com with ESMTPS id s4si2251212pgh.540.2019.02.14.22.34.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 14 Feb 2019 22:34:17 -0800 (PST) Received-SPF: pass (google.com: domain of ying.huang@intel.com designates 134.134.136.24 as permitted sender) client-ip=134.134.136.24; Authentication-Results: mx.google.com; spf=pass (google.com: domain of ying.huang@intel.com designates 134.134.136.24 as permitted sender) smtp.mailfrom=ying.huang@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Feb 2019 22:34:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,371,1544515200"; d="scan'208";a="134502115" Received: from yhuang-dev.sh.intel.com (HELO yhuang-dev) ([10.239.159.151]) by orsmga002.jf.intel.com with ESMTP; 14 Feb 2019 22:34:13 -0800 From: "Huang\, Ying" To: Andrea Parri Cc: Andrew Morton , , , Hugh Dickins , "Paul E . McKenney" , Minchan Kim , Johannes Weiner , Tim Chen , Mel Gorman , Jérôme Glisse , Michal Hocko , Andrea Arcangeli , David Rientjes , Rik van Riel , Jan Kara , Dave Jiang , Daniel Jordan Subject: Re: [PATCH -mm -V7] mm, swap: fix race between swapoff and some swap operations References: <20190211083846.18888-1-ying.huang@intel.com> <20190212101316.GA6905@andrea> Date: Fri, 15 Feb 2019 14:34:09 +0800 In-Reply-To: <20190212101316.GA6905@andrea> (Andrea Parri's message of "Tue, 12 Feb 2019 11:13:16 +0100") Message-ID: <87a7ixblwe.fsf@yhuang-dev.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii 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: Andrea Parri writes: >> Alternative implementation could be replacing disable preemption with >> rcu_read_lock_sched and stop_machine() with synchronize_sched(). > > JFYI, starting with v4.20-rc1, synchronize_rcu{,expedited}() also wait > for preempt-disable sections (the intent seems to retire the RCU-sched > update-side API), so that here you could instead use preempt-disable + > synchronize_rcu{,expedited}(). This LWN article gives an overview of > the latest RCU API/semantics changes: https://lwn.net/Articles/777036/. Thanks a lot! The article is really helpful! Best Regards, Huang, Ying > Andrea