From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755740AbYG2G3a (ORCPT ); Tue, 29 Jul 2008 02:29:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751923AbYG2G3W (ORCPT ); Tue, 29 Jul 2008 02:29:22 -0400 Received: from gw.goop.org ([64.81.55.164]:42948 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751914AbYG2G3W (ORCPT ); Tue, 29 Jul 2008 02:29:22 -0400 Message-ID: <488EB8BE.8050806@goop.org> Date: Mon, 28 Jul 2008 23:29:18 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Andi Kleen CC: Ingo Molnar , Jens Axboe , Linux Kernel Mailing List Subject: Re: x86: Is there still value in having a special tlb flush IPI vector? References: <488E534F.2030204@goop.org> <488E5455.6010901@goop.org> <20080729021215.GG30344@one.firstfloor.org> In-Reply-To: <20080729021215.GG30344@one.firstfloor.org> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: >>> Now that normal smp_function_call is no longer an enormous bottleneck, >>> > > Hmm? It still uses a global lock at least as of current git tree. Yes, but it's only held briefly to put things onto the list. It doesn't get held over the whole IPI transaction as the old smp_call_function did, and the tlb flush code still does. RCU is used to manage the list walk and freeing, so there's no long-held locks there either. J