From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id D99F0280244 for ; Thu, 4 Jan 2018 05:21:16 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id k44so646099wre.1 for ; Thu, 04 Jan 2018 02:21:16 -0800 (PST) Received: from outbound-smtp16.blacknight.com (outbound-smtp16.blacknight.com. [46.22.139.233]) by mx.google.com with ESMTPS id p46si16566edc.208.2018.01.04.02.21.15 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Jan 2018 02:21:15 -0800 (PST) Received: from mail.blacknight.com (pemlinmail03.blacknight.ie [81.17.254.16]) by outbound-smtp16.blacknight.com (Postfix) with ESMTPS id 62F621C21AF for ; Thu, 4 Jan 2018 10:21:15 +0000 (GMT) Date: Thu, 4 Jan 2018 10:21:14 +0000 From: Mel Gorman Subject: Re: [PATCH -V4 -mm] mm, swap: Fix race between swapoff and some swap operations Message-ID: <20180104102114.l45sjluuzdgpcfd7@techsingularity.net> References: <871sjopllj.fsf@yhuang-dev.intel.com> <20171221235813.GA29033@bbox> <87r2rmj1d8.fsf@yhuang-dev.intel.com> <20171223013653.GB5279@bgram> <20180102102103.mpah2ehglufwhzle@suse.de> <20180102112955.GA29170@quack2.suse.cz> <20180102132908.hv3qwxqpz7h2jyqp@techsingularity.net> <87o9mbixi0.fsf@yhuang-dev.intel.com> <20180103095408.pqxggi7voser7ia3@techsingularity.net> <87lgheh173.fsf@yhuang-dev.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <87lgheh173.fsf@yhuang-dev.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Huang, Ying" Cc: Jan Kara , Mel Gorman , Minchan Kim , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , "Paul E . McKenney" , Johannes Weiner , Tim Chen , Shaohua Li , J???r???me Glisse , Michal Hocko , Andrea Arcangeli , David Rientjes , Rik van Riel , Dave Jiang , Aaron Lu On Thu, Jan 04, 2018 at 09:17:36AM +0800, Huang, Ying wrote: > > Maybe, but in this particular case, I would prefer to go with something > > more conventional unless there is strong evidence that it's an improvement > > (which I doubt in this case given the cost of migration overall and the > > corner case of migrating a dirty page). > > So you like page_lock() more than RCU? In this instance, yes. > Is there any problem of RCU? > The object to be protected isn't clear? > It's not clear what object is being protected or how it's protected and it's not the usual means a mapping is pinned. Furthermore, in the event a page is being truncated, we really do not want to bother doing any migration work for compaction purposes as it's a waste. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org