From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dax.scot.redhat.com (sct@dax.scot.redhat.com [195.89.149.242]) by kvack.org (8.8.7/8.8.7) with ESMTP id RAA00514 for ; Mon, 7 Dec 1998 17:56:39 -0500 Date: Mon, 7 Dec 1998 22:56:26 GMT Message-Id: <199812072256.WAA04256@dax.scot.redhat.com> From: "Stephen C. Tweedie" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: readahead/behind algorithm In-Reply-To: References: Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: Linux MM , Alan Cox , Stephen Tweedie List-ID: Hi, On Mon, 7 Dec 1998 21:17:56 +0100 (CET), Rik van Riel said: > Hi, > I've thought a bit about what the 'ideal' readahead/behind > algorithm would be and reached the following conclusion. > 1. we test the presence of pages in the proximity of the > faulting page (31 behind, 32 ahead) building a map of > 64 pages. It will only be useful to start getting complex here if we take more care about maintaining the logical contiguity of pages when we swap them. If swap gets fragmented, then doing this sort of readahead will just use up bandwidth without giving any measurable performance gains. It would be better thinking along those lines right now, I suspect. --Stephen -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org