From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 19 Aug 2001 03:17:30 +0200 From: Andrea Arcangeli Subject: Re: resend Re: [PATCH] final merging patch -- significant mozilla speedup. Message-ID: <20010819031730.V1719@athlon.random> References: <20010819023548.P1719@athlon.random> <20010819025532.S1719@athlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20010819025532.S1719@athlon.random>; from andrea@suse.de on Sun, Aug 19, 2001 at 02:55:32AM +0200 Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Ben LaHaise , torvalds@transmeta.com, alan@redhat.com, linux-mm@kvack.org, Chris Blizzard List-ID: On Sun, Aug 19, 2001 at 02:55:32AM +0200, Andrea Arcangeli wrote: > On Sat, Aug 18, 2001 at 09:50:04PM -0300, Rik van Riel wrote: > > On Sun, 19 Aug 2001, Andrea Arcangeli wrote: > > > On Sat, Aug 18, 2001 at 08:10:50PM -0400, Ben LaHaise wrote: > > > > > > Your patch performs a few odd things like: > > > > > > > > + vma->vm_raend = 0; > > ... > > > > which I would argue are incorrect. Remember that page faults rely on > > > > > > vm_raend is obviously correct. > > > > Why ? > > Do you know of any piece of code that touches vm_raend without the the > mmap_sem acquired? If yes you will change my mind about it otherwise you > will know why. btw, while my change to madvise is obviously correct (madvise holds the write sem), I noticed now that the other code changing vm_raend is racy (but this is totally unrelated to my changes): the nopage callback during the page fault updates the vm_raend with only the read semaphore acquired so multiple threads could get confused, however it seems a controlled race that cannot harm. 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-mm.org/