From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id 4CDB36B021D for ; Thu, 29 Apr 2010 11:40:36 -0400 (EDT) Message-ID: <4BD9A84C.3050709@redhat.com> Date: Thu, 29 Apr 2010 11:39:56 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [RFC PATCH -v3] take all anon_vma locks in anon_vma_lock References: <1272403852-10479-1-git-send-email-mel@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> <4BD8EA85.2000209@redhat.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: Andrea Arcangeli , Mel Gorman , Linux-MM , LKML , KAMEZAWA Hiroyuki , Christoph Lameter , Andrew Morton List-ID: On 04/28/2010 10:55 PM, Minchan Kim wrote: > When you tried anon_vma_chain patches as I pointed out, what I have a > concern is parent's vma not child's one. > The vma of parent still has N anon_vma. No, it is the other way around. The anon_vma of the parent is also present in all of the children, so the parent anon_vma is attached to N vmas. However, the parent vma only has 1 anon_vma attached to it, and each of the children will have 2 anon_vmas. That is what should keep any locking overhead with this patch minimal. Yes, a deep fork bomb can slow itself down. Too bad, don't do that :) -- 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