Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757657Ab3HMOXm (ORCPT ); Tue, 13 Aug 2013 10:23:42 -0400 Received: from kanga.kvack.org ([205.233.56.17]:36476 "EHLO kanga.kvack.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757092Ab3HMOXl (ORCPT ); Tue, 13 Aug 2013 10:23:41 -0400 Date: Tue, 13 Aug 2013 10:23:38 -0400 From: Benjamin LaHaise To: Krzysztof Kozlowski Cc: Minchan Kim , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Seth Jennings , Mel Gorman , guz.fnst@cn.fujitsu.com, Dave Hansen , lliubbo@gmail.com, aquini@redhat.com, Rik van Riel , Tomasz Stanislawski Subject: Re: [RFC 0/3] Pin page control subsystem Message-ID: <20130813142338.GD13330@kvack.org> References: <1376377502-28207-1-git-send-email-minchan@kernel.org> <1376387202.31048.2.camel@AMDC1943> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1376387202.31048.2.camel@AMDC1943> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1372 Lines: 34 On Tue, Aug 13, 2013 at 11:46:42AM +0200, Krzysztof Kozlowski wrote: > Hi Minchan, > > On wto, 2013-08-13 at 16:04 +0900, Minchan Kim wrote: > > patch 2 introduce pinpage control > > subsystem. So, subsystems want to control pinpage should implement own > > pinpage_xxx functions because each subsystem would have other character > > so what kinds of data structure for managing pinpage information depends > > on them. Otherwise, they can use general functions defined in pinpage > > subsystem. patch 3 hacks migration.c so that migration is > > aware of pinpage now and migrate them with pinpage subsystem. > > I wonder why don't we use page->mapping and a_ops? Is there any > disadvantage of such mapping/a_ops? That's what the pending aio patches do, and I think this is a better approach for those use-cases that the technique works for. The biggest problem I see with the pinpage approach is that it's based on a single page at a time. I'd venture a guess that many pinned pages are done in groups of pages, not single ones. -ben > Best regards, > Krzysztof -- "Thought is the essence of where you are now." -- 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/