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 8A48A6B0047 for ; Fri, 1 Oct 2010 08:08:10 -0400 (EDT) Message-ID: <4CA5CF17.1090807@redhat.com> Date: Fri, 01 Oct 2010 08:07:51 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 0/2] Reduce mmap_sem hold times during file backed page faults References: <1285909484-30958-1-git-send-email-walken@google.com> In-Reply-To: <1285909484-30958-1-git-send-email-walken@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Michel Lespinasse Cc: linux-mm@kvack.org, Linus Torvalds , Ying Han , linux-kernel@vger.kernel.org, Andrew Morton , Nick Piggin , Peter Zijlstra , Hugh Dickins List-ID: On 10/01/2010 01:04 AM, Michel Lespinasse wrote: > Linus, I would appreciate your comments on this since you shot down the > previous proposal. I hope you'll find this approach is sane, but I would > be interested to hear if you have specific objections. > > mmap_sem is very coarse grained (per process) and has long read-hold times > (disk latencies); this breaks down rapidly for workloads that use both > read and write mmap_sem acquires. This short patch series tries to reduce > mmap_sem hold times when faulting in file backed VMAs. The changes make sense to me, but it would be good to know what kind of benefits you have seen with these patches. Especially performance numbers :) -- 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