From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753334Ab1AYURD (ORCPT ); Tue, 25 Jan 2011 15:17:03 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:58261 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752101Ab1AYURB (ORCPT ); Tue, 25 Jan 2011 15:17:01 -0500 MIME-Version: 1.0 In-Reply-To: <20110125174908.262260777@chello.nl> References: <20110125173111.720927511@chello.nl> <20110125174908.262260777@chello.nl> From: Linus Torvalds Date: Wed, 26 Jan 2011 06:16:08 +1000 Message-ID: Subject: Re: [PATCH 20/25] mm: Simplify anon_vma refcounts To: Peter Zijlstra Cc: Andrea Arcangeli , Avi Kivity , Thomas Gleixner , Rik van Riel , Ingo Molnar , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, Benjamin Herrenschmidt , David Miller , Hugh Dickins , Mel Gorman , Nick Piggin , Paul McKenney , Yanmin Zhang , Hugh Dickins Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 26, 2011 at 3:31 AM, Peter Zijlstra wrote: > > This patch changes the anon_vma refcount to be 0 when the object is > free. It does this by adding 1 ref to being in use in the anon_vma > structure (iow. the anon_vma->head list is not empty). Why is this patch part of this series, rather than being an independent patch before the whole series? I think this part of the series is the only total no-brainer, ie we should have done this from the beginning. The preemptability stuff I'm more nervous about (performance issues? semantic differences?) Linus From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id DB0E56B0092 for ; Tue, 25 Jan 2011 15:17:13 -0500 (EST) Received: from mail-iw0-f169.google.com (mail-iw0-f169.google.com [209.85.214.169]) (authenticated bits=0) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id p0PKGWHJ021452 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=FAIL) for ; Tue, 25 Jan 2011 12:16:33 -0800 Received: by iwn40 with SMTP id 40so183107iwn.14 for ; Tue, 25 Jan 2011 12:16:32 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20110125174908.262260777@chello.nl> References: <20110125173111.720927511@chello.nl> <20110125174908.262260777@chello.nl> From: Linus Torvalds Date: Wed, 26 Jan 2011 06:16:08 +1000 Message-ID: Subject: Re: [PATCH 20/25] mm: Simplify anon_vma refcounts Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: Andrea Arcangeli , Avi Kivity , Thomas Gleixner , Rik van Riel , Ingo Molnar , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, Benjamin Herrenschmidt , David Miller , Hugh Dickins , Mel Gorman , Nick Piggin , Paul McKenney , Yanmin Zhang , Hugh Dickins List-ID: On Wed, Jan 26, 2011 at 3:31 AM, Peter Zijlstra wrote: > > This patch changes the anon_vma refcount to be 0 when the object is > free. It does this by adding 1 ref to being in use in the anon_vma > structure (iow. the anon_vma->head list is not empty). Why is this patch part of this series, rather than being an independent patch before the whole series? I think this part of the series is the only total no-brainer, ie we should have done this from the beginning. The preemptability stuff I'm more nervous about (performance issues? semantic differences?) Linus -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org