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 KAA24876 for ; Tue, 1 Dec 1998 10:13:31 -0500 Date: Tue, 1 Dec 1998 15:13:22 GMT Message-Id: <199812011513.PAA18172@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: [PATCH] swapin readahead In-Reply-To: References: Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: Linux MM , Stephen Tweedie List-ID: Hi Rik, In article , Rik van Riel writes: > here is a very first primitive version of as swapin > readahead patch. It seems to give much increased > throughput to swap and the desktop switch time has > decreased noticably. > The checks are all needed. The first two checks are there > to avoid annoying messages from swap_state.c :)) There's a third check needed, I think, which probably accounts for the swap_duplicate errors people have been noting. You need to skip pages which are marked as locked in the swap_lockmap, or the async page read may block (you might be trying to read in a page which is still being written to swap). In this case, by the time you have slept, the swap entry is not necessarily still in use, so you may end up reading an unused swap entry. That would certainly lead to swap_duplicate warnings, although I think they should be benign. --Stephen -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org