From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 027D36B01F6 for ; Wed, 28 Apr 2010 20:28:27 -0400 (EDT) Received: by iwn40 with SMTP id 40so5925913iwn.1 for ; Wed, 28 Apr 2010 17:28:26 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20100428165734.6541bab3@annuminas.surriel.com> References: <1272403852-10479-1-git-send-email-mel@csn.ul.ie> <20100427231007.GA510@random.random> <20100428091555.GB15815@csn.ul.ie> <20100428153525.GR510@random.random> <20100428155558.GI15815@csn.ul.ie> <20100428162305.GX510@random.random> <20100428134719.32e8011b@annuminas.surriel.com> <20100428142510.09984e15@annuminas.surriel.com> <20100428161711.5a815fa8@annuminas.surriel.com> <20100428165734.6541bab3@annuminas.surriel.com> Date: Thu, 29 Apr 2010 09:28:25 +0900 Message-ID: Subject: Re: [RFC PATCH -v3] take all anon_vma locks in anon_vma_lock From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: Andrea Arcangeli , Mel Gorman , Linux-MM , LKML , KAMEZAWA Hiroyuki , Christoph Lameter , Andrew Morton List-ID: On Thu, Apr 29, 2010 at 5:57 AM, Rik van Riel wrote: > Take all the locks for all the anon_vmas in anon_vma_lock, this properly > excludes migration and the transparent hugepage code from VMA changes don= e > by mmap/munmap/mprotect/expand_stack/etc... > > Unfortunately, this requires adding a new lock (mm->anon_vma_chain_lock), > otherwise we have an unavoidable lock ordering conflict. =C2=A0This chang= es the > locking rules for the "same_vma" list to be either mm->mmap_sem for write= , > or mm->mmap_sem for read plus the new mm->anon_vma_chain lock. =C2=A0This= limits > the place where the new lock is taken to 2 locations - anon_vma_prepare a= nd > expand_downwards. > > Document the locking rules for the same_vma list in the anon_vma_chain an= d > remove the anon_vma_lock call from expand_upwards, which does not need it= . > > Signed-off-by: Rik van Riel This patch makes things simple. So I like this. Actually, I wanted this all-at-once locks approach. But I was worried about that how the patch affects AIM 7 workload which is cause of anon_vma_chain about scalability by Rik. But now Rik himself is sending the patch. So I assume the patch couldn't decrease scalability of the workload heavily. Let's wait result of test if Rik doesn't have a problem of AIM7. --=20 Kind regards, Minchan Kim -- 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