From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <42837A84.5070307@engr.sgi.com> Date: Thu, 12 May 2005 10:47:16 -0500 From: Ray Bryant MIME-Version: 1.0 Subject: Re: [Lhms-devel] Re: [PATCH 2.6.12-rc3 1/8] mm: manual page migration-rc2 -- xfs-extended-attributes-rc2.patch References: <20050511043756.10876.72079.60115@jackhammer.engr.sgi.com> <20050511043802.10876.60521.51027@jackhammer.engr.sgi.com> <20050511071538.GA23090@infradead.org> <4281F650.2020807@engr.sgi.com> <20050511195003.GA2468@infradead.org> <4282798F.8060005@engr.sgi.com> <20050512095535.GA14409@infradead.org> In-Reply-To: <20050512095535.GA14409@infradead.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Hellwig Cc: Ray Bryant , Hirokazu Takahashi , Marcelo Tosatti , Andi Kleen , Dave Hansen , linux-mm , Nathan Scott , Ray Bryant , lhms-devel@lists.sourceforge.net, Jes Sorensen List-ID: Christoph Hellwig wrote: > > When you talk about files you're already in the special casing business. > Only few vmas are file-backed and it makes lots of sense to mark an > anonymous vma non-migratable. > > I disagree. Here's a couple of random cases: (1) /bin/bash. /proc/pid maps shows it has 39 vmas. 30 of them are file backed. (2) blastwaves (a sample CFD code). /proc/pid maps shows 49 vmas. 33 of them are file backed. So, it seems to me that most vmas you encounter (by count) are mapped files. On the other hand, based on size, most pages would be mapped by anonymous vmas with the obvious exception being large mapped files. In all the thinking we've done about page migration, we have never once come across a case where anonymous vmas shouldn't be migrated. Can you describe to me an example where it would be useful to not migrate an anonymous vma? -- Best Regards, Ray ----------------------------------------------- Ray Bryant 512-453-9679 (work) 512-507-7807 (cell) raybry@sgi.com raybry@austin.rr.com The box said: "Requires Windows 98 or better", so I installed Linux. ----------------------------------------------- -- 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: aart@kvack.org