From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752840AbaANAXb (ORCPT ); Mon, 13 Jan 2014 19:23:31 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:53790 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752105AbaANAX1 (ORCPT ); Mon, 13 Jan 2014 19:23:27 -0500 Date: Mon, 13 Jan 2014 16:23:25 -0800 From: Andrew Morton To: Minchan Kim Cc: linux-kernel@vger.kernel.org, Nitin Gupta , Jerome Marchand , Sergey Senozhatsky Subject: Re: [PATCH 4/7] zram: use atomic operation for stat Message-Id: <20140113162325.93896b1928f2c4a320f52d80@linux-foundation.org> In-Reply-To: <20140114001935.GW1992@bbox> References: <1389611942-15544-1-git-send-email-minchan@kernel.org> <1389611942-15544-5-git-send-email-minchan@kernel.org> <20140113155814.07ab74c8f77179fc770a8e5f@linux-foundation.org> <20140114001935.GW1992@bbox> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 14 Jan 2014 09:19:35 +0900 Minchan Kim wrote: > On Mon, Jan 13, 2014 at 03:58:14PM -0800, Andrew Morton wrote: > > On Mon, 13 Jan 2014 20:18:59 +0900 Minchan Kim wrote: > > > > > Some of fields in zram->stats are protected by zram->lock which > > > is rather coarse-grained so let's use atomic operation without > > > explict locking. > > > > Confused. The patch didn't remove any locking, so it made the code > > slower. > > True but it could make remove dependency of zram->lock for 32bit stat > so further patches can remove messy code and enhance write performance. > So, it's preparing patch for further step. > Should I rewrite the description to explain this? That would be useful ;) I'd ask for performance testing results but I expect they'll say "no difference". I grabbed patches 1-3 as they seems appropriate for 3.14.