From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 3CE166B0226 for ; Sat, 24 Apr 2010 07:14:15 -0400 (EDT) Date: Sat, 24 Apr 2010 13:13:40 +0200 From: Andrea Arcangeli Subject: Re: [PATCH 04/14] mm,migration: Allow the migration of PageSwapCache pages Message-ID: <20100424111340.GB32034@random.random> References: <20100422193106.9ffad4ec.kamezawa.hiroyu@jp.fujitsu.com> <20100422195153.d91c1c9e.kamezawa.hiroyu@jp.fujitsu.com> <1271946226.2100.211.camel@barrios-desktop> <1271947206.2100.216.camel@barrios-desktop> <20100422154443.GD30306@csn.ul.ie> <20100423183135.GT32034@random.random> <20100423192311.GC14351@csn.ul.ie> <20100423193948.GU32034@random.random> <20100423213549.GV32034@random.random> <20100424105226.GF14351@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100424105226.GF14351@csn.ul.ie> Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: Minchan Kim , KAMEZAWA Hiroyuki , Christoph Lameter , Andrew Morton , Adam Litke , Avi Kivity , David Rientjes , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Sat, Apr 24, 2010 at 11:52:27AM +0100, Mel Gorman wrote: > I think you're right. This is a new bug introduced by the anon_vma changes. On > the plus side, it means we don't have to worry about -stable. Correct, no worry about -stable. > > vma_adjust already takes the anon_vma->lock and of course I also > > further verified that trying to apply your snippet to vma_adjust > > results in immediately deadlock as the very same lock is already taken > > in my tree as it's the same anon-vma (simpler). > > Yes, I expected that. Previously, there was only one anon_vma so if you > double-take the lock, bad things happen. > > > So aa.git will be > > immune from these bugs for now. > > > > It should be. I expect that's why you have never seen the bugon in > swapops. Correct, I never seen it, and I keep it under very great stress with swap storms of hugepages, lots of I/O and khugepaged at 100% cpu. Also keep in mind expand_downwards which also adjusts vm_start/vm_pgoff the same way (and without mmap_sem write mode). -- 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/ . Don't email: email@kvack.org