Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757560Ab3HOPgG (ORCPT ); Thu, 15 Aug 2013 11:36:06 -0400 Received: from a9-99.smtp-out.amazonses.com ([54.240.9.99]:44328 "EHLO a9-99.smtp-out.amazonses.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755854Ab3HOPgE (ORCPT ); Thu, 15 Aug 2013 11:36:04 -0400 X-Greylist: delayed 1040 seconds by postgrey-1.27 at vger.kernel.org; Thu, 15 Aug 2013 11:36:04 EDT Date: Thu, 15 Aug 2013 15:18:40 +0000 From: Christoph Lameter To: Minchan Kim cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, k.kozlowski@samsung.com, Seth Jennings , Mel Gorman , guz.fnst@cn.fujitsu.com, Benjamin LaHaise , Dave Hansen , lliubbo@gmail.com, aquini@redhat.com, Rik van Riel Subject: Re: [RFC 0/3] Pin page control subsystem In-Reply-To: <20130815044834.GB3139@gmail.com> Message-ID: <00000140828ea17e-d69af79a-1d8e-4df2-9513-492df5e00afc-000000@email.amazonses.com> References: <1376377502-28207-1-git-send-email-minchan@kernel.org> <00000140787b6191-ae3f2eb1-515e-48a1-8e64-502772af4700-000000@email.amazonses.com> <20130814001236.GC2271@bbox> <000001407dafbe92-7b2b4006-2225-4f0b-b23b-d66101a995aa-000000@email.amazonses.com> <20130814164705.GD2706@gmail.com> <000001407dc3c33b-4139d615-aecc-4745-a9b4-c84949f6a8f4-000000@email.amazonses.com> <20130815044834.GB3139@gmail.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SES-Outgoing: 2013.08.15-54.240.9.99 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1129 Lines: 22 On Thu, 15 Aug 2013, Minchan Kim wrote: > Now mlock pages could be migrated in case of CMA so I think it's not a > big problem to migrate it for other cases. > I remember You and Peter argued what's the mlock semainc of pin POV > and as I remember correctly, Peter said mlock doesn't mean pin so > we could migrate it but you didn't agree. Right? mlock means it can be migrated. Pinning is currently done by increasing the page count. Migration will be attempted but it will fail since the references cannot be all removed. Peter proposed that mlock would work like pinning so that a migration of the page would not be attempted. My concern is not only about migration but about a general way of pinning pages. Having mlock and pinning with different semantics is already an issue as the conversation with Peter brought out. Now we are adding yet another way that pinning is used. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/