Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755124AbZGVNpI (ORCPT ); Wed, 22 Jul 2009 09:45:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753828AbZGVNpE (ORCPT ); Wed, 22 Jul 2009 09:45:04 -0400 Received: from wf-out-1314.google.com ([209.85.200.174]:14763 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752015AbZGVNpC convert rfc822-to-8bit (ORCPT ); Wed, 22 Jul 2009 09:45:02 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=AqhVyrcIm7H8t0r/7ucQ+XVfIG7KfeCR+n4L1zhEWpDePH4QYkHB3Axb89G4amwZfi /lXrge52Cz170sX6Fo3N8H0YnUlaR6LqELQ5/8PjJz9ne6gxbnUkMmCbsazO+19jgoVf BQ/peg/SJAg/Bw9S+NT0ikzvDa9/ek1Gq6L+4= MIME-Version: 1.0 In-Reply-To: <1248268755.27058.1426.camel@twins> References: <1248267513-4934-1-git-send-email-tom.leiming@gmail.com> <1248267513-4934-2-git-send-email-tom.leiming@gmail.com> <1248267513-4934-3-git-send-email-tom.leiming@gmail.com> <1248267830.27058.1404.camel@twins> <1248268755.27058.1426.camel@twins> Date: Wed, 22 Jul 2009 21:45:02 +0800 Message-ID: Subject: Re: [tip:core/locking 2/3] lockdep:define preallocated "stack" for BFS as per cpu variable From: Ming Lei To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, mingo@elte.hu, torvalds@linux-foundation.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1054 Lines: 29 2009/7/22 Peter Zijlstra : > On Wed, 2009-07-22 at 21:10 +0800, Ming Lei wrote: >> 2009/7/22 Peter Zijlstra : >> > On Wed, 2009-07-22 at 20:58 +0800, tom.leiming@gmail.com wrote: >> >> From: Ming Lei >> > >> > This patch can use a changelog. >> > >> > Why is this needed, isn't all that serialized by the graph_lock anyway? >> > Or are there a few paths where this isn't the case and we're now racy? >> >> It is really serialized by the graph_lock, but we can prevent cpu cache from >> being flushing by different cpu access, ?which seems that can be avoided by >> per cpu variables. Right? > > I doubt it'll make a difference, got any numbers to back that up? OK, I'll design some test case to get the numbers. Thanks. -- Lei Ming -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/