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 C3C466B01EE for ; Wed, 12 May 2010 17:02:10 -0400 (EDT) Message-ID: <4BEB1732.1010503@redhat.com> Date: Wed, 12 May 2010 17:01:38 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 3/5] track the root (oldest) anon_vma References: <20100512133815.0d048a86@annuminas.surriel.com> <20100512133958.3aff0515@annuminas.surriel.com> <20100512205941.GO24989@csn.ul.ie> In-Reply-To: <20100512205941.GO24989@csn.ul.ie> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: Andrew Morton , Andrea Arcangeli , Minchan Kim , Linux-MM , KAMEZAWA Hiroyuki , LKML , Linus Torvalds List-ID: On 05/12/2010 04:59 PM, Mel Gorman wrote: > On Wed, May 12, 2010 at 01:39:58PM -0400, Rik van Riel wrote: >> Subject: track the root (oldest) anon_vma >> >> Track the root (oldest) anon_vma in each anon_vma tree. Because we only >> take the lock on the root anon_vma, we cannot use the lock on higher-up >> anon_vmas to lock anything. This makes it impossible to do an indirect >> lookup of the root anon_vma, since the data structures could go away from >> under us. >> >> However, a direct pointer is safe because the root anon_vma is always the >> last one that gets freed on munmap or exit, by virtue of the same_vma list >> order and unlink_anon_vmas walking the list forward. >> > > Shouldn't this be "usually the last one that gets freed" because of the > ref-counting by KSM aspect? Minor nit anyway. It needs to be the last one that gets freed. Patch 5/5 makes sure that it is when KSM refcounting is involved. >> Signed-off-by: Rik van Riel > > Otherwise > > Acked-by: Mel Gorman Thank you for reviewing these patches. -- All rights reversed -- 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