From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751297AbdAMIH5 (ORCPT ); Fri, 13 Jan 2017 03:07:57 -0500 Received: from LGEAMRELO13.lge.com ([156.147.23.53]:34355 "EHLO lgeamrelo13.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751151AbdAMIH4 (ORCPT ); Fri, 13 Jan 2017 03:07:56 -0500 X-Original-SENDERIP: 156.147.1.127 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 165.244.249.25 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.223.161 X-Original-MAILFROM: minchan@kernel.org Date: Fri, 13 Jan 2017 17:03:30 +0900 From: Minchan Kim To: Sergey Senozhatsky CC: , , , , , , , , , , Subject: Re: [PATCH] mm: extend zero pages to same element pages for zram Message-ID: <20170113080330.GB8018@bbox> References: <1483692145-75357-1-git-send-email-zhouxianrong@huawei.com> <20170109234110.GA10298@bbox> <20170113042444.GE9360@jagdpanzerIV.localdomain> <20170113062343.GA7827@bbox> <20170113063614.GA484@jagdpanzerIV.localdomain> <20170113064719.GA8018@bbox> <20170113070245.GB484@jagdpanzerIV.localdomain> MIME-Version: 1.0 In-Reply-To: <20170113070245.GB484@jagdpanzerIV.localdomain> User-Agent: Mutt/1.5.24 (2015-08-30) X-MIMETrack: Itemize by SMTP Server on LGEKRMHUB06/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/01/13 17:03:32, Serialize by Router on LGEKRMHUB06/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/01/13 17:03:32, Serialize complete at 2017/01/13 17:03:32 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 13, 2017 at 04:02:45PM +0900, Sergey Senozhatsky wrote: > On (01/13/17 15:47), Minchan Kim wrote: > [..] > > > > Could you elaborate a bit? Do you mean this? > > > > > > > > ret = scnprintf(buf, PAGE_SIZE, > > > > "%8llu %8llu %8llu %8lu %8ld %8llu %8lu\n", > > > > orig_size << PAGE_SHIFT, > > > > (u64)atomic64_read(&zram->stats.compr_data_size), > > > > mem_used << PAGE_SHIFT, > > > > zram->limit_pages << PAGE_SHIFT, > > > > max_used << PAGE_SHIFT, > > > > // (u64)atomic64_read(&zram->stats.zero_pages), > > > > (u64)atomic64_read(&zram->stats.same_pages), > > > > pool_stats.pages_compacted); > > > > > > yes, correct. > > > > > > do we need to export it as two different stats (zero_pages and > > > same_pages), if those are basically same thing internally? > > > > So, let summary up. > > > > 1. replace zero_page stat into same page stat in mm_stat > > 2. s/zero_pages/same_pages/Documentation/blockdev/zram.txt > > 3. No need to warn to "cat /sys/block/zram0/mm_stat" user to see zero_pages > > about semantic change > > 1) account zero_page and same_pages in one attr. > > this already is in the patch. > > 2) do not rename zero_pages attr. > > we can't do this so fast, I think. > > > > 3. No need to warn to "cat /sys/block/zram0/mm_stat" user to see zero_pages > > about semantic change > > yes. we just _may_ have more pages (depending on data pattern) which we treat > as "zero" pages internally. this results in lower memory consumption. I don't > think warn users about this change is necessary; they won't be able to do > anything about it anyway. zero_pages stat is pretty much just a fun number to > know. isn't it? > I just wanted to confirm your thought. I hope anyone doesn't is sensitive on that number. ;) Let's replace zero_page stat field in mm_stat. Thanks.