Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755288AbZGVNKy (ORCPT ); Wed, 22 Jul 2009 09:10:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754892AbZGVNKx (ORCPT ); Wed, 22 Jul 2009 09:10:53 -0400 Received: from mail-pz0-f180.google.com ([209.85.222.180]:41279 "EHLO mail-pz0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754148AbZGVNKx (ORCPT ); Wed, 22 Jul 2009 09:10:53 -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=PHbQMSP1B1MxQpkjwZYE3nhmEx9/K0ab6xk6t88J8qCKMO0sHytD/gEjRywZkNpjzd ZLL06/MMvZ+OoleNjq3kszzlmcMGdQI3UloB7ODH0i7r71CsQ6Rbj9Fs4RACszL/N58u 2wv5/l/iYQsLFqk8RtCJYwTN9vW4C2NIvIoEA= MIME-Version: 1.0 In-Reply-To: <1248267830.27058.1404.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> Date: Wed, 22 Jul 2009 21:10:53 +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: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 792 Lines: 22 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? 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/