From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 26 Sep 2000 16:05:54 +0200 From: Andrea Arcangeli Subject: Re: [patch] vmfixes-2.4.0-test9-B2 - fixing deadlocks Message-ID: <20000926160554.B13832@athlon.random> References: <20000924224303.C2615@redhat.com> <20000925001342.I5571@athlon.random> <20000925003650.A20748@home.ds9a.nl> <20000925014137.B6249@athlon.random> <20000925172442.J2615@redhat.com> <20000925190347.E27677@athlon.random> <20000925190657.N2615@redhat.com> <20000925213242.A30832@athlon.random> <20000925205457.Y2615@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ; from cr@sap.com on Tue, Sep 26, 2000 at 08:54:23AM +0200 Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Rohland Cc: "Stephen C. Tweedie" , Ingo Molnar , Linus Torvalds , Rik van Riel , Roger Larsson , MM mailing list , linux-kernel@vger.kernel.org List-ID: On Tue, Sep 26, 2000 at 08:54:23AM +0200, Christoph Rohland wrote: > "Stephen C. Tweedie" writes: > > > Hi, > > > > On Mon, Sep 25, 2000 at 09:32:42PM +0200, Andrea Arcangeli wrote: > > > > > Having shrink_mmap that browse the mapped page cache is useless > > > as having shrink_mmap browsing kernel memory and anonymous pages > > > as it does in 2.2.x as far I can tell. It's an algorithm > > > complexity problem and it will waste lots of CPU. > > > > It's a compromise between CPU cost and Getting It Right. Ignoring the > > mmap is not a good solution either. > > > > > Now think this simple real life example. A 2G RAM machine running > > > an executable image of 1.5G, 300M in shm and 200M in cache. > > Hey that's ridiculous: 1.5G executable image and 300M shm? Take it > vice-versa and you are approaching real life. Could you tell me what's wrong in having an app with a 1.5G mapped executable (or a tiny executable but with a 1.5G shared/private file mapping if you prefer), 300M of shm (or 300M of anonymous memory if you prefer) and 200M as filesystem cache? The application have a misc I/O load that in some part will run out of the working set, what's wrong with this? What's ridiculous? Please elaborate. To emulate that workload we only need to mmap(1.5G, MAP_PRIVATE or MAP_SHARED), fault into it, and run bonnie. 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/