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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 088F3C433EF for ; Fri, 29 Oct 2021 02:34:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE4BB61107 for ; Fri, 29 Oct 2021 02:34:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231558AbhJ2Cgq (ORCPT ); Thu, 28 Oct 2021 22:36:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:41770 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231348AbhJ2Cgp (ORCPT ); Thu, 28 Oct 2021 22:36:45 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B34B9610E8; Fri, 29 Oct 2021 02:34:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635474857; bh=k+q5cwoUghGqcxAWgg2DvpUzWPsMNg2BWCU7/8wFZa4=; h=Date:Subject:From:To:Cc:References:In-Reply-To:From; b=Wjlt4z8uedxdmPbxVmntoWKxUtK1PCMg6UhhRS2GjRL5BPldvNWCkCuNNk5c6QY7t EAHlcGlVj0LmFtRsg+KtLAOxFOoddwdGDKnvf7mkjtsZEP4KbrPfAjXJGuigL2kxdj zREKIPRrchp4xGG1eEl+4qm/C6pwfIIQ0MwpuwXXGOokqeH/MOlAflGSzhudm8VyAX NA6qFggxKuibIyeNOOTiZa6hs7gP6akDvleMi+WEYtuCDM2+/AAPHZvjsj93QrpWe2 fy0AnFYAfWKw8s0WOJsV+uUjreJoUXREWnptT7NLxKFoRPDLjPMcX/qWw5xYi+9Teb Aly8eiIr9mzXg== Message-ID: Date: Fri, 29 Oct 2021 10:34:14 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.0.3 Subject: Re: [f2fs-dev] [PATCH] f2fs: skip f2fs_preallocate_blocks() for overwrite case Content-Language: en-US From: Chao Yu To: Jaegeuk Kim Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net References: <20210928151911.11189-1-chao@kernel.org> <65f6c366-9e5b-fe7f-7c38-061996d1882b@kernel.org> In-Reply-To: <65f6c366-9e5b-fe7f-7c38-061996d1882b@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 Ping, On 2021/9/29 8:05, Chao Yu wrote: > On 2021/9/29 3:08, Jaegeuk Kim wrote: >> On 09/28, Chao Yu wrote: >>> In f2fs_file_write_iter(), let's use f2fs_overwrite_io() to >>> check whethere it is overwrite case, for such case, we can skip >>> f2fs_preallocate_blocks() in order to avoid f2fs_do_map_lock(), >>> which may be blocked by checkpoint() potentially. >>> >>> Signed-off-by: Chao Yu >>> --- >>>   fs/f2fs/file.c | 4 ++++ >>>   1 file changed, 4 insertions(+) >>> >>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >>> index 13deae03df06..51fecb2f4db5 100644 >>> --- a/fs/f2fs/file.c >>> +++ b/fs/f2fs/file.c >>> @@ -4321,6 +4321,10 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) >>>           preallocated = true; >>>           target_size = iocb->ki_pos + iov_iter_count(from); >>> +        if (f2fs_overwrite_io(inode, iocb->ki_pos, >>> +                        iov_iter_count(from))) >>> +            goto write; >> >> This calls f2fs_map_blocks() which can be duplicate, if it's not the overwirte >> case. Do we have other benefit? > > f2fs_overwrite_io() will break for append write case w/ below check: > >     if (pos + len > i_size_read(inode)) >         return false; > > I guess we may only suffer double f2fs_map_blocks() for write hole > case, e.g. truncate to large size & write inside the filesize. For > this case, how about adding a condition to allow double f2fs_map_blocks() > only if write size is smaller than a threshold? > > Thanks, > >> >>> + >>>           err = f2fs_preallocate_blocks(iocb, from); >>>           if (err) { >>>   out_err: >>> -- >>> 2.32.0 > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.sourceforge.net%2Flists%2Flistinfo%2Flinux-f2fs-devel&data=04%7C01%7Cchao.yu%40oppo.com%7C421c06812eba4f922b0908d982dcdcc5%7Cf1905eb1c35341c5951662b4a54b5ee6%7C0%7C0%7C637684707374940190%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=u22eEWDAPaAZCyISyjTUOtQDLDuyKxTnNCI3eSwwWro%3D&reserved=0