From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 18 Sep 2007 10:54:43 +0100 Subject: Re: [PATCH/RFC 6/14] Reclaim Scalability: "No Reclaim LRU Infrastructure" Message-ID: <20070918095443.GA2035@skynet.ie> References: <20070914205359.6536.98017.sendpatchset@localhost> <20070914205438.6536.49500.sendpatchset@localhost> <1190042245.5460.81.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: From: mel@skynet.ie (Mel Gorman) Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Lee Schermerhorn , linux-mm@kvack.org, akpm@linux-foundation.org, riel@redhat.com, balbir@linux.vnet.ibm.com, andrea@suse.de, a.p.zijlstra@chello.nl, eric.whitney@hp.com, npiggin@suse.de List-ID: On (17/09/07 11:41), Christoph Lameter didst pronounce: > On Mon, 17 Sep 2007, Lee Schermerhorn wrote: > > > > One fleeting thought here: It may be useful to *not* allocate known > > > unreclaimable pages with __GFP_MOVABLE. > > > > Sorry, I don't understand where you're coming from here. > > Non-reclaimable pages should be migratable, but maybe __GFP_MOVABLE > > means something else? > > True. __GFP_MOVABLE + MLOCK is movable. Yes. Right now, it's rare we actually move them but the patches exist to make it possible when we find it to be a real problem. > Also the ramfs/shmem pages. There > may be uses though that require a page to stay put because it is used for > some nefarious I/O purpose by a driver. RDMA comes to mind. Yeah :/ > Maybe we need > some additional option that works like MLOCK but forbids migration. The problem with RDMA that I recall is that we don't know at allocation time that they may be unmovable sometimes in the future. I didn't think of a way around that problem. > Those > would then be unreclaimable and not __GFP_MOVABLE. I know some of our > applications create huge amount of these. > Can you think of a way that pages that will be later pinned by something like RDMA can be identified in advance? -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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