From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756245AbbE2Oys (ORCPT ); Fri, 29 May 2015 10:54:48 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:34290 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753184AbbE2Oy1 (ORCPT ); Fri, 29 May 2015 10:54:27 -0400 Date: Fri, 29 May 2015 23:54:19 +0900 From: Minchan Kim To: Sergey Senozhatsky Cc: Weijie Yang , "'Andrew Morton'" , ngupta@vflare.org, "'Weijie Yang'" , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] zram: clear disk io accounting when reset zram device Message-ID: <20150529145418.GG11609@blaptop> References: <"000001d099be$fae6cc90$f0b465b0$@yang"@samsung.com> <20150529034141.GA1157@swordfish> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150529034141.GA1157@swordfish> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello guys, On Fri, May 29, 2015 at 12:41:41PM +0900, Sergey Senozhatsky wrote: > On (05/29/15 11:23), Weijie Yang wrote: > > This patch clears zram disk io accounting when reset the zram device, > > if don't do this, the residual io accounting stat will affect the > > diskstat in the next zram active cycle. Thanks for the fix. > > > > thanks. my bad. > > Acked-by: Sergey Senozhatsky Acked-by: Minchan Kim I give my acked-by because it's surely fix so there is no reason to hesitate. In future, I hope to change it like below. I think the problem is caused from weired feature "reset" of zram. Until a while ago, we didn't have hot_add/del feature so we should use custom reset function but now we have hot/add feature. So reset is logically same feature(ie, reset = hot_remove+hot_add but remains same device id). If we reuse zram_remove/add for reset, finally it calls del_gendisk which will do part_stat_set_all for us so we didn't have this kinds of problems. It needs more churns and some tweaks of zram_[remove|add] but it's more clean and consistent between reset and hot_remove. Just my two cents. > > -ss > > > Signed-off-by: Weijie Yang > > --- > > drivers/block/zram/zram_drv.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > > index 8dcbced..6e134f4 100644 > > --- a/drivers/block/zram/zram_drv.c > > +++ b/drivers/block/zram/zram_drv.c > > @@ -805,7 +805,9 @@ static void zram_reset_device(struct zram *zram) > > memset(&zram->stats, 0, sizeof(zram->stats)); > > zram->disksize = 0; > > zram->max_comp_streams = 1; > > + > > set_capacity(zram->disk, 0); > > + part_stat_set_all(&zram->disk->part0, 0); > > > > up_write(&zram->init_lock); > > /* I/O operation under all of CPU are done so let's free */ > > -- > > 1.7.10.4 > > > > -- Kind regards, Minchan Kim