Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965819AbXEKSF7 (ORCPT ); Fri, 11 May 2007 14:05:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760155AbXEKSFu (ORCPT ); Fri, 11 May 2007 14:05:50 -0400 Received: from smtp1.linux-foundation.org ([65.172.181.25]:50839 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759813AbXEKSFt (ORCPT ); Fri, 11 May 2007 14:05:49 -0400 Date: Fri, 11 May 2007 11:05:22 -0700 From: Andrew Morton To: Christoph Lameter Cc: Peter Zijlstra , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Oleg Nesterov , Ingo Molnar , Thomas Gleixner , Nick Piggin Subject: Re: [PATCH 1/2] scalable rw_mutex Message-Id: <20070511110522.ed459635.akpm@linux-foundation.org> In-Reply-To: References: <20070511131541.992688403@chello.nl> <20070511132321.895740140@chello.nl> <20070511093108.495feb70.akpm@linux-foundation.org> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 747 Lines: 19 On Fri, 11 May 2007 10:07:17 -0700 (PDT) Christoph Lameter wrote: > On Fri, 11 May 2007, Andrew Morton wrote: > > > yipes. percpu_counter_sum() is expensive. > > Capable of triggering NMI watchdog on 4096+ processors? Well. That would be a millisecond per cpu which sounds improbable. And we'd need to be calling it under local_irq_save() which we presently don't. And nobody has reported any problems against the existing callsites. But it's no speed demon, that's for sure. - 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/