From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756155AbYJGGYe (ORCPT ); Tue, 7 Oct 2008 02:24:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751488AbYJGGYZ (ORCPT ); Tue, 7 Oct 2008 02:24:25 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:58788 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751245AbYJGGYY (ORCPT ); Tue, 7 Oct 2008 02:24:24 -0400 Date: Mon, 6 Oct 2008 23:23:22 -0700 From: Andrew Morton To: "Theodore Ts'o" Cc: "Aneesh Kumar K.V" , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org Subject: Re: [PATCH, RFC] percpu_counters: make fbc->count read atomic on 32 bit architecture Message-Id: <20081006232322.c383fac5.akpm@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 05 Oct 2008 21:28:10 -0400 "Theodore Ts'o" wrote: > The following patch has been sitting in the ext4 patch queue for about > six weeks. It was there it was a suspected cause for block allocation > bug. As I recall, it we found the true root cause since then, but this > has stuck around since it's a potential problem. Andrew has expressed > concerns that this patch might have performance impacts. Performace impacts I guess we'll just have to put up with. iirc I was thinking that this implementation should be pushed down to a kernel-wide atomic64_t and then the percpu_counters would just use that type.