From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH]: Free pages from local pcp lists under tight memory conditions From: Rohit Seth In-Reply-To: <20051123132647.257710b9.akpm@osdl.org> References: <20051122161000.A22430@unix-os.sc.intel.com> <1132775194.25086.54.camel@akash.sc.intel.com> <20051123115545.69087adf.akpm@osdl.org> <1132779605.25086.69.camel@akash.sc.intel.com> <20051123132647.257710b9.akpm@osdl.org> Content-Type: text/plain Date: Wed, 23 Nov 2005 13:40:48 -0800 Message-Id: <1132782048.25086.76.camel@akash.sc.intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: clameter@engr.sgi.com, torvalds@osdl.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Wed, 2005-11-23 at 13:26 -0800, Andrew Morton wrote: > Rohit Seth wrote: > > > > > I don't think Martin was able to demonstrate much benefit from the lock > > > contention reduction on 16-way NUMAQ either. > > > > > > So I dithered for months and it was a marginal merge, so it's appropriate > > > to justify the continued presence of the code. > > > > > > > May be the limits on the number of pages hanging on the per_cpu_pagelist > > was (or even now is) too small (for them to give any meaningful gain). > > May be we should have more physical contiguity in each of these pcps to > > give better cache spread. > > Could be. The initial settings were pretty arbitrary - I assumed that > someone would get in and tune them up, but nothing much happened. Perhaps > we should expose the thresholds in /proc/sys/vm so they're easier to play > with. Most certainly. If I had a patch ready...I would have given you one right away :-) Though I will work on it... It surely is unfortunate that we have not digged deeper into this area (in terms of optimizations).... -rohit -- 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