From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH 02/10] mm: system wide ALLOC_NO_WATERMARK From: Peter Zijlstra In-Reply-To: <200708061121.50351.phillips@phunq.net> References: <20070806102922.907530000@chello.nl> <20070806103658.107883000@chello.nl> <200708061121.50351.phillips@phunq.net> Content-Type: text/plain Date: Mon, 06 Aug 2007 20:31:02 +0200 Message-Id: <1186425063.11797.80.camel@lappy> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Daniel Phillips Cc: Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Miller , Andrew Morton , Daniel Phillips , Pekka Enberg , Matt Mackall , Lee Schermerhorn , Steve Dickson List-ID: On Mon, 2007-08-06 at 11:21 -0700, Daniel Phillips wrote: > On Monday 06 August 2007 11:11, Christoph Lameter wrote: > > On Mon, 6 Aug 2007, Peter Zijlstra wrote: > > > Change ALLOC_NO_WATERMARK page allocation such that dipping into > > > the reserves becomes a system wide event. > > > > Shudder. That can just be a desaster for NUMA. Both performance wise > > and logic wise. One cpuset being low on memory should not affect > > applications in other cpusets. Do note that these are only PF_MEMALLOC allocations that will break the cpuset. And one can argue that these are not application allocation but system allocations. > Currently your system likely would have died here, so ending up with a > reserve page temporarily on the wrong node is already an improvement. > > I agree that the reserve pool should be per-node in the end, but I do > not think that serves the interest of simplifying the initial patch > set. How about a numa performance patch that adds onto the end of > Peter's series? Trouble with keeping this per node is that all the code dealing with the reserve needs to keep per-cpu state, which given that the system is really crawling at that moment, seems excessive. -- 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