From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 11 Jul 2000 20:00:23 +0200 (CEST) From: Andrea Arcangeli Subject: Re: [PATCH] 2.2.17pre7 VM enhancement Re: I/O performance on 2.4.0-test2 In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: "Stephen C. Tweedie" , Marcelo Tosatti , Jens Axboe , Alan Cox , Derek Martin , Linux Kernel , linux-mm@kvack.org, "David S. Miller" List-ID: On Tue, 11 Jul 2000, Rik van Riel wrote: >On Tue, 11 Jul 2000, Andrea Arcangeli wrote: >> On Tue, 11 Jul 2000, Rik van Riel wrote: >> >> >No. You just wrote down the strongest argument in favour of one >> >unified queue for all types of memory usage. >> >> Do that and download an dozen of iso image with gigabit ethernet >> in background. > >You need to forget about LRU for a moment. The fact that >LRU is fundamentally broken doesn't mean that it has >anything whatsoever to do with whether we age all pages >fairly or whether we prefer some pages over other pages. > >If LRU is broken we need to fix that, a workaround like >your proposal doesn't fix anything in this case. So tell me how with your design can I avoid the kernel to unmap anything while running: cp /dev/zero . forever. Whatever aging algorithm you use if you wait enough time the mapped pages will be thrown away eventually. If the above `cp` is able to throw away _everything_ eventually, that will be a major problem IMHO and I don't agree in using a long-term-design that can't avoid that so common problem. Andrea -- 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.eu.org/Linux-MM/