From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from haymarket.ed.ac.uk (haymarket.ed.ac.uk [129.215.128.53]) by kvack.org (8.8.7/8.8.7) with ESMTP id KAA30896 for ; Wed, 22 Jul 1998 10:27:53 -0400 Date: Wed, 22 Jul 1998 11:36:38 +0100 Message-Id: <199807221036.LAA00829@dax.dcs.ed.ac.uk> From: "Stephen C. Tweedie" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: More info: 2.1.108 page cache performance on low memory In-Reply-To: References: <199807131653.RAA06838@dax.dcs.ed.ac.uk> <199807141730.SAA07239@dax.dcs.ed.ac.uk> <87d8b370ge.fsf@atlas.CARNet.hr> Sender: owner-linux-mm@kvack.org To: "Eric W. Biederman" Cc: Zlatko.Calusic@CARNet.hr, "Stephen C. Tweedie" , linux-mm@kvack.org List-ID: Hi, On 18 Jul 1998 11:40:20 -0500, ebiederm+eric@npwt.net (Eric W. Biederman) said: > Agreed. We should look very carefully though to see if any aging > solution increases fragmentation. According to Stephen the current > one does, and this may be a natural result of aging and not just a > single implementation :( No no no! The current VM has two separate but related problems. First is that it keeps too much cache in low memory configurations, and that appears to be much much better in 2.1.109 and 110. Second is the fragmentation issue, but that's a lot harder to address I'm afraid. I have a zoned allocator now working which does help enormously: it's the first time my VM-test 2.1 configuration has _ever_ been able to run successfully with 8k NFS. However, the zoned allocation can use memory less efficiently: the odd free pages in the paged zone cannot be used by non-paged users and vice versa, so overall performance may suffer. Right now I'm cleaning the code up for a release against 2.1.110 so that we can start testing. --Stephen -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org