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 PAA31317 for ; Mon, 27 Jul 1998 15:48:51 -0400 Date: Mon, 27 Jul 1998 12:02:02 +0100 Message-Id: <199807271102.MAA00713@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: <87iukovq42.fsf@atlas.CARNet.hr> Sender: owner-linux-mm@kvack.org To: ebiederm+eric@npwt.net Cc: Zlatko Calusic , "Stephen C. Tweedie" , linux-mm@kvack.org List-ID: Hi, On Sun, 26 Jul 1998 09:49:02 -0500 (CDT), Eric W Biederman said: > From where I sit it looks completly possible to give the buffer cache a > fake inode, and have it use the same mechanisms that I have developed for > handling other dirty data in the page cache. It should also be possible > in this effort to simplify the buffer_head structure as well. > As time permits I'll move in that direction. You'd still have to persuade people that it's a good idea. I'm not convinced. The reason for having things in the page cache is for fast lookup. For this to make sense for the buffer cache, you'd have to align the buffer cache on page boundaries, but buffers on disk are not naturally aligned this way. You'd end up wasting a lot of space as perhaps only a few of the buffers in any page were useful, and you'd also have to keep track of which buffers within the page were valid/dirty. We *need* a mechanism which is block-aligned, not page-aligned. The buffer cache is a good way of doing it. Forcing block device caching into a page-aligned cache is not necessarily going to simplify things. --Stephen -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org