From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD78CC433EF for ; Tue, 8 Feb 2022 09:18:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353688AbiBHJSN (ORCPT ); Tue, 8 Feb 2022 04:18:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238582AbiBHJSK (ORCPT ); Tue, 8 Feb 2022 04:18:10 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEA5CC03FEC3 for ; Tue, 8 Feb 2022 01:18:06 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8B02961465 for ; Tue, 8 Feb 2022 09:18:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23CD4C340EE; Tue, 8 Feb 2022 09:18:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644311886; bh=I7Xie7sMfICHs14aE9eDxrmpTe6fMPFsk6GoOxJmkV8=; h=Date:Subject:From:To:Cc:References:In-Reply-To:From; b=g2SIl1sv37Wg4HfiTuc4dZnLg2S/byf3jUtnH3uIc4WvhjoID1lqvjW6LXqKoZ09y KJaXGAbCLiMOl0wys7ZCmWmeT2Fx2xPwaTXoZ3ZZJZ6lVnKu3/rQkqPNJ1f5NEJeMk 1Ovl49WTI0DoSyXnD9KNIDP39i5U+0J28WZuuFMKPe+UV2PbVEY93HpsSm6pkDcWOo zi9BuuErpypqH+TrJl38bj6QOjzLVmakbAjevbg858sHUeDausKlm4Tsu3MfoJDQXh Ei3Wb7fUIFDqoMCTQGPh/JHreg5ddJVjBg2shjWIIvmLVKeAMytFsfIEb4Ruc3xhCQ qUjloscENnUNg== Message-ID: <2cd93012-16b8-6681-cabe-c1401987bf27@kernel.org> Date: Tue, 8 Feb 2022 17:18:02 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid unneeded preflush during checkpoint() Content-Language: en-US From: Chao Yu To: Jaegeuk Kim Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net References: <20220207113516.9489-1-chao@kernel.org> <59da7f3e-92bd-1165-00e3-3dc18ae19aea@kernel.org> In-Reply-To: <59da7f3e-92bd-1165-00e3-3dc18ae19aea@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/2/8 9:35, Chao Yu wrote: > On 2022/2/8 3:14, Jaegeuk Kim wrote: >> On 02/07, Chao Yu wrote: >>> During checkpoint, we have committed preflush command via f2fs_flush_device_cache() >> >>   787 int f2fs_flush_device_cache(struct f2fs_sb_info *sbi) >>   788 { >>   789         int ret = 0, i; >>   790 >>   791         if (!f2fs_is_multi_device(sbi)) >>   792                 return 0; >> >> Seems a wrong assumption. > > Oh, I missed that f2fs_flush_device_cache was introduced to flush devices except > first device when multi-device feature is on. > >     for (i = 1; i < sbi->s_ndevs; i++) { >         int count = DEFAULT_RETRY_IO_COUNT; > > So, this patch seems wrong... > > Instead, below case looks wrong since it needs to trigger flush during checkpoint() > no matter nobarrier is on or off. Wrong comments, let's ignore this patch, sorry. Thanks, > >     if (test_opt(sbi, NOBARRIER)) >         return 0; > > Thanks, > >> >>> to persist all metadata pages except last #2 CP pack page, so we don't need to >>> commit another preflush command in commit_checkpoint(), remove it to avoid unneeded >>> write cache overhead. >>> >>> Signed-off-by: Chao Yu >>> --- >>>   fs/f2fs/data.c | 2 +- >>>   1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >>> index 8c417864c66a..15ac18bbbc8e 100644 >>> --- a/fs/f2fs/data.c >>> +++ b/fs/f2fs/data.c >>> @@ -598,7 +598,7 @@ static void __f2fs_submit_merged_write(struct f2fs_sb_info *sbi, >>>           io->fio.op = REQ_OP_WRITE; >>>           io->fio.op_flags = REQ_META | REQ_PRIO | REQ_SYNC; >>>           if (!test_opt(sbi, NOBARRIER)) >>> -            io->fio.op_flags |= REQ_PREFLUSH | REQ_FUA; >>> +            io->fio.op_flags |= REQ_FUA; >>>       } >>>       __submit_merged_bio(io); >>>       up_write(&io->io_rwsem); >>> -- >>> 2.32.0 > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel