From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 16 Jul 2001 14:19:15 +0100 From: "Stephen C. Tweedie" Subject: Re: [PATCH] Separate global/perzone inactive/free shortage Message-ID: <20010716141915.C28023@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ; from mikeg@wen-online.de on Sat, Jul 14, 2001 at 10:34:39AM +0200 Sender: owner-linux-mm@kvack.org Return-Path: To: Mike Galbraith Cc: Marcelo Tosatti , Rik van Riel , Dirk Wetter , "Stephen C. Tweedie" , linux-mm@kvack.org List-ID: Hi, > On Sat, 14 Jul 2001, Marcelo Tosatti wrote: > On highmem machines, wouldn't it save a LOT of time to prevent allocation > of ZONE_DMA as VM pages? Or, if we really need to, get those pages into > the swapcache instantly? Crawling through nearly 4 gig of VM looking for > 16 MB of ram has got to be very expensive. Besides, those pages are just > too precious to allow some user task to sit on them. Can't we balance that automatically? Why not just round-robin between the eligible zones when allocating, biasing each zone based on size? On a 4GB box you'd basically end up doing 3 times as many allocations from the highmem zone as the normal zone and only very occasionally would you try to dig into the dma zone. But on a 32MB box you would automatically spread allocations 50/50 between normal and dma, and on a 20MB box you would be biased in favour of allocating dma pages. Cheers, Stephen -- 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/