From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750743AbdAWGHb (ORCPT ); Mon, 23 Jan 2017 01:07:31 -0500 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:49605 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750703AbdAWGHb (ORCPT ); Mon, 23 Jan 2017 01:07:31 -0500 X-Original-SENDERIP: 156.147.1.151 X-Original-MAILFROM: iamjoonsoo.kim@lge.com X-Original-SENDERIP: 10.177.222.138 X-Original-MAILFROM: iamjoonsoo.kim@lge.com Date: Mon, 23 Jan 2017 15:13:50 +0900 From: Joonsoo Kim To: Minchan Kim Cc: zhouxianrong , Andrew Morton , Sergey Senozhatsky , linux-kernel@vger.kernel.org, Mi.Sophia.Wang@huawei.com, zhouxiyu@huawei.com, weidu.du@huawei.com, zhangshiming5@huawei.com, won.ho.park@huawei.com Subject: Re: [PATCH v3] zram: extend zero pages to same element pages Message-ID: <20170123061350.GE24581@js1304-P5Q-DELUXE> References: <1485136523-14325-1-git-send-email-minchan@kernel.org> <20170123030222.GB24581@js1304-P5Q-DELUXE> <5fc21686-6f5f-df04-bedf-a361d3c25112@huawei.com> <20170123044720.GA11763@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170123044720.GA11763@bbox> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 23, 2017 at 01:47:20PM +0900, Minchan Kim wrote: > Hello, > > When I look at first patch, I wanted to use increment loop but didn't > tell to you because that small piece of code is no harmful for readbility > to me so I want to keep author's code rather than pointing the trivial > which is just matter of preference out. > > Rather than readiblity, I suspect it might hurt performance and talked > with Namhyung but we cannot find anything decremental loop is bad > compared to incremental. Rather than, many articles have been said > decrement loop is faster like zhouxianrong's mentiond although I don't > think it makes marginal difference. > > Joonsoo, why do you think incremental is faster? > zhouxianrong, why do you think decrement loops makes cache problem? > > I'm okay either way. Just want to know why you guys think about it. Hmm... I guess that cache prefetcher works better for forward access but I'm not sure. Thanks.