From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 8 Nov 2004 14:28:37 -0800 From: Andrew Morton Subject: Re: [PATCH] ignore referenced pages on reclaim when OOM Message-Id: <20041108142837.307029fc.akpm@osdl.org> In-Reply-To: References: <16783.59834.7179.464876@thebsh.namesys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: nikita@clusterfs.com, marcelo.tosatti@cyclades.com, linux-mm@kvack.org List-ID: Rik van Riel wrote: > > On Tue, 9 Nov 2004, Nikita Danilov wrote: > > > > Speeds up extreme load performance on Rik's tests. > > > > I recently tested quite similar thing, the only dfference being that in > > my case references bit started being ignored when scanning priority > > reached 2 rather than 0. > > > > I found that it _degrades_ performance in the loads when there is a lot > > of file system write-back going from tail of the inactive list (like > > dirtying huge file through mmap in a loop). > > Well yeah, when you reach priority 2, you've only scanned > 1/4 of memory. On the other hand, when you reach priority > 0, you've already scanned all pages once - beyond that point > the referenced bit really doesn't buy you much any more. > But we have to scan active, referenced pages two times to move them onto the inactive list. A bit more, really, because nowadays refill_inactive_zone() doesn't even run page_referenced() until it starts to reach higher scanning priorities. So it could be that we're just not scanning enough. -- 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