From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 1AF356007BA for ; Tue, 5 Jan 2010 08:43:17 -0500 (EST) Date: Tue, 5 Jan 2010 05:45:36 -0800 From: Arjan van de Ven Subject: Re: [RFC][PATCH 6/8] mm: handle_speculative_fault() Message-ID: <20100105054536.44bf8002@infradead.org> In-Reply-To: <20100104182813.753545361@chello.nl> References: <20100104182429.833180340@chello.nl> <20100104182813.753545361@chello.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: "Paul E. McKenney" , Peter Zijlstra , KAMEZAWA Hiroyuki , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "minchan.kim@gmail.com" , cl@linux-foundation.org, "hugh.dickins" , Nick Piggin , Ingo Molnar , Linus Torvalds List-ID: On Mon, 04 Jan 2010 19:24:35 +0100 Peter Zijlstra wrote: > Generic speculative fault handler, tries to service a pagefault > without holding mmap_sem. while I appreciate the goal of reducing contention on this lock... wouldn't step one be to remove the page zeroing from under this lock? that's by far (easily by 10x I would guess) the most expensive thing that's done under the lock, and I would expect a first order of contention reduction just by having the zeroing of a page not done under the lock... -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- 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