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 X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A6D3C0650F for ; Tue, 6 Aug 2019 00:37:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 03603216B7 for ; Tue, 6 Aug 2019 00:37:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565051874; bh=sbaxTE7kYFCFGs3ifzk0BZVFtKFrLdqe3vyYh0wqMBU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=wk8h1uvRW4kSD+gfQbN0NMhwy64TQNEfUpXzjFL/03Wglhuc389sV61tcf0iMtM5w EC6ch8PIZJ9uZ0aLY+GO7l7jOl/AFW5ZzUVrPvQfqUNrzq9LJ5LtEKVscDvP3wPe3g vxHHrPY3HNCACorID9bC/+yFpZI20AXuSfieTLdg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731171AbfHFAhw (ORCPT ); Mon, 5 Aug 2019 20:37:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:55380 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728870AbfHFAhw (ORCPT ); Mon, 5 Aug 2019 20:37:52 -0400 Received: from localhost (unknown [104.132.0.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 88D332147A; Tue, 6 Aug 2019 00:37:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565051870; bh=sbaxTE7kYFCFGs3ifzk0BZVFtKFrLdqe3vyYh0wqMBU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ScwRm8hYp7YQfd8Ar9IxfsD1IvTjjwbM9jdo1Kd4SoDa8WR86nXNa01XPZU3REWWy wvgcV2VQ+AR7KTnMyIVtNtSIv5ux4o6nw94lUm18wR6u88fn6RXCw85FNO/Ohe7xFP waJwBcl7zjIbk+x0JP69cudAjwY/VbY5Nq3Xko2w= Date: Mon, 5 Aug 2019 17:37:49 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, chao@kernel.org Subject: Re: [PATCH v2] f2fs: separate NOCoW and pinfile semantics Message-ID: <20190806003749.GB98101@jaegeuk-macbookpro.roam.corp.google.com> References: <20190723023640.GC60778@jaegeuk-macbookpro.roam.corp.google.com> <20190729055738.GA95664@jaegeuk-macbookpro.roam.corp.google.com> <07cd3aba-3516-9ba5-286e-277abb98e244@huawei.com> <20190730180231.GB76478@jaegeuk-macbookpro.roam.corp.google.com> <00e70eb1-c4fa-a6c9-69d7-71ff995c7d6c@huawei.com> <20190801041435.GB84433@jaegeuk-macbookpro.roam.corp.google.com> <20190801222746.GA27597@jaegeuk-macbookpro.roam.corp.google.com> <5d566fce-4412-65b2-e9d9-279b648f7551@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5d566fce-4412-65b2-e9d9-279b648f7551@huawei.com> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/02, Chao Yu wrote: > On 2019/8/2 6:27, Jaegeuk Kim wrote: > > On 08/01, Chao Yu wrote: > >> On 2019/8/1 12:14, Jaegeuk Kim wrote: > >>> On 07/31, Chao Yu wrote: > >>>> On 2019/7/31 2:02, Jaegeuk Kim wrote: > >>>>> On 07/29, Chao Yu wrote: > >>>>>> On 2019/7/29 13:57, Jaegeuk Kim wrote: > >>>>>>> On 07/23, Chao Yu wrote: > >>>>>>>> On 2019/7/23 10:36, Jaegeuk Kim wrote: > >>>>>>>>> On 07/19, Chao Yu wrote: > >>>>>>>>>> Pinning a file is heavy, because skipping pinned files make GC > >>>>>>>>>> running with heavy load or no effect. > >>>>>>>>> > >>>>>>>>> Pinned file is a part of NOCOW files, so I don't think we can simply drop it > >>>>>>>>> for backward compatibility. > >>>>>>>> > >>>>>>>> Yes, > >>>>>>>> > >>>>>>>> But what I concerned is that pin file is too heavy, so in order to satisfy below > >>>>>>>> demand, how about introducing pin_file_2 flag to triggering IPU only during > >>>>>>>> flush/writeback. > >>>>>>> > >>>>>>> That can be done by cold files? > >>>>>> > >>>>>> Then it may inherit property of cold type file, e.g. a) goes into cold area; b) > >>>>>> update with very low frequency. > >>>>>> > >>>>>> Actually pin_file_2 could be used by db-wal/log file, which are updated > >>>>>> frequently, and should go to hot/warm area, it does not match above two property. > >>>>> > >>>>> How about considering another name like "IPU-only mode"? > >>>>> > >>>>> fallocate write Flag GC > >>>>> Pin_file: preallocate IPU FS_NOCOW_FL Not allowed > >>>>> IPU_file: Not preallocate IPU N/A Default by temperature > >>>> > >>>> One question, do we need preallocate physical block address for IPU_file as > >>>> Pin_file? since it can enhance db file's sequential read performance, not sure, > >>>> db can handle random data in preallocated blocks. > >>> > >>> db file will do atomic writes, which can not be used with this. -wal may be able > >> > >> Now WAL mode were set by default in Android, so most of db file are -wal type now. > > > > Will be back again tho. > > R? Q. > > > > >> > >>> to preallocate blocks, but it can eat disk space unnecessarily. > >> > >> I meant .db-wal file rather than .db. > >> > >> Yes, that's ext4 style, that would bring better performance due to less holes in > >> block distribution. > >> > >> I don't think we need to worry about space issue for db-wal file. I tracked > >> .db-wal file's update before: > >> - there are very frequently truncation and deletion, that means the preallocated > >> blocks won't exist for long time. > >> - and also there are very frequently append writes, I suspect there almost very > >> few preallocate block are not written. > >> - total db-wal file number is less. > > > > Sometimes it can be large enough for system. > > For this, it's trade off: > - lose a few disk space at the very begin of db-wal lifecycle Or > - face fragment and read performance degradation. > > > If it's from user apps and short lived, why do we need preallocation? > > It triggers sequential read on db-wal file during checkpoint, though it's short > lived, still it can affect performance. > > What do you think of doing some performance test on WAL file to decide the > preallocation policy? Good idea. Can we? > > Thanks, > > > > >> > >>> > >>>> > >>>> Other behaviors looks good to me. :) > >>>> > >>>> I plan to use last bit in inode.i_inline to store this flag. > >>> > >>> Why not using i_flag like FS_NOCOW_FL? > >> > >> Oops, as you listed in last email, I can see you don't want to break > >> FS_NOCOW_FL's semantics for backward compatibility. > >> > >> Flag > >> IPU_file N/A > >> > >> If we plan to use FS_NOCOW_FL, that's what this patch has already did, you can > >> merge it directly... :P > >> > >>> > >>>> > >>>>> Cold_file: Not preallocate IPU N/A Move in cold area > >>>>> Hot_file: Not preallocate IPU/OPU N/A Move in hot area > >>>> > >>>> Should hot file be gced to hot area? That would mix new hot data with old 'hot' > >>>> data which actually become cold. > >>> > >>> But, user explicitly specified this is hot. > >> > >> With current implementation, GC will migrate data from hot/warm/cold area to > >> cold area. > >> > >> Thanks, > >> > >>> > >>>> > >>>> Thanks, > >>>> > >>>>> > >>>>>> > >>>>>> Thank, > >>>>>> > >>>>>>> > >>>>>>>> > >>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> So that this patch propose to separate nocow and pinfile semantics: > >>>>>>>>>> - NOCoW flag can only be set on regular file. > >>>>>>>>>> - NOCoW file will only trigger IPU at common writeback/flush. > >>>>>>>>>> - NOCow file will do OPU during GC. > >>>>>>>>>> > >>>>>>>>>> For the demand of 1) avoid fragment of file's physical block and > >>>>>>>>>> 2) userspace don't care about file's specific physical address, > >>>>>>>>>> tagging file as NOCoW will be cheaper than pinned one. > >>>>>>>> > >>>>>>>> ^^^ > >>>>>>>> > >>>>>>>> Thanks, > >>>>>>>> > >>>>>>>>>> > >>>>>>>>>> Signed-off-by: Chao Yu > >>>>>>>>>> --- > >>>>>>>>>> v2: > >>>>>>>>>> - rebase code to fix compile error. > >>>>>>>>>> fs/f2fs/data.c | 3 ++- > >>>>>>>>>> fs/f2fs/f2fs.h | 1 + > >>>>>>>>>> fs/f2fs/file.c | 22 +++++++++++++++++++--- > >>>>>>>>>> 3 files changed, 22 insertions(+), 4 deletions(-) > >>>>>>>>>> > >>>>>>>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > >>>>>>>>>> index a2a28bb269bf..15fb8954c363 100644 > >>>>>>>>>> --- a/fs/f2fs/data.c > >>>>>>>>>> +++ b/fs/f2fs/data.c > >>>>>>>>>> @@ -1884,7 +1884,8 @@ static inline bool check_inplace_update_policy(struct inode *inode, > >>>>>>>>>> > >>>>>>>>>> bool f2fs_should_update_inplace(struct inode *inode, struct f2fs_io_info *fio) > >>>>>>>>>> { > >>>>>>>>>> - if (f2fs_is_pinned_file(inode)) > >>>>>>>>>> + if (f2fs_is_pinned_file(inode) || > >>>>>>>>>> + F2FS_I(inode)->i_flags & F2FS_NOCOW_FL) > >>>>>>>>>> return true; > >>>>>>>>>> > >>>>>>>>>> /* if this is cold file, we should overwrite to avoid fragmentation */ > >>>>>>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > >>>>>>>>>> index 596ab3e1dd7b..f6c5a3d2e659 100644 > >>>>>>>>>> --- a/fs/f2fs/f2fs.h > >>>>>>>>>> +++ b/fs/f2fs/f2fs.h > >>>>>>>>>> @@ -2374,6 +2374,7 @@ static inline void f2fs_change_bit(unsigned int nr, char *addr) > >>>>>>>>>> #define F2FS_NOATIME_FL 0x00000080 /* do not update atime */ > >>>>>>>>>> #define F2FS_INDEX_FL 0x00001000 /* hash-indexed directory */ > >>>>>>>>>> #define F2FS_DIRSYNC_FL 0x00010000 /* dirsync behaviour (directories only) */ > >>>>>>>>>> +#define F2FS_NOCOW_FL 0x00800000 /* Do not cow file */ > >>>>>>>>>> #define F2FS_PROJINHERIT_FL 0x20000000 /* Create with parents projid */ > >>>>>>>>>> > >>>>>>>>>> /* Flags that should be inherited by new inodes from their parent. */ > >>>>>>>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > >>>>>>>>>> index 7ca545874060..ae0fec54cac6 100644 > >>>>>>>>>> --- a/fs/f2fs/file.c > >>>>>>>>>> +++ b/fs/f2fs/file.c > >>>>>>>>>> @@ -1692,6 +1692,7 @@ static const struct { > >>>>>>>>>> { F2FS_NOATIME_FL, FS_NOATIME_FL }, > >>>>>>>>>> { F2FS_INDEX_FL, FS_INDEX_FL }, > >>>>>>>>>> { F2FS_DIRSYNC_FL, FS_DIRSYNC_FL }, > >>>>>>>>>> + { F2FS_NOCOW_FL, FS_NOCOW_FL }, > >>>>>>>>>> { F2FS_PROJINHERIT_FL, FS_PROJINHERIT_FL }, > >>>>>>>>>> }; > >>>>>>>>>> > >>>>>>>>>> @@ -1715,7 +1716,8 @@ static const struct { > >>>>>>>>>> FS_NODUMP_FL | \ > >>>>>>>>>> FS_NOATIME_FL | \ > >>>>>>>>>> FS_DIRSYNC_FL | \ > >>>>>>>>>> - FS_PROJINHERIT_FL) > >>>>>>>>>> + FS_PROJINHERIT_FL | \ > >>>>>>>>>> + FS_NOCOW_FL) > >>>>>>>>>> > >>>>>>>>>> /* Convert f2fs on-disk i_flags to FS_IOC_{GET,SET}FLAGS flags */ > >>>>>>>>>> static inline u32 f2fs_iflags_to_fsflags(u32 iflags) > >>>>>>>>>> @@ -1753,8 +1755,6 @@ static int f2fs_ioc_getflags(struct file *filp, unsigned long arg) > >>>>>>>>>> fsflags |= FS_ENCRYPT_FL; > >>>>>>>>>> if (f2fs_has_inline_data(inode) || f2fs_has_inline_dentry(inode)) > >>>>>>>>>> fsflags |= FS_INLINE_DATA_FL; > >>>>>>>>>> - if (is_inode_flag_set(inode, FI_PIN_FILE)) > >>>>>>>>>> - fsflags |= FS_NOCOW_FL; > >>>>>>>>>> > >>>>>>>>>> fsflags &= F2FS_GETTABLE_FS_FL; > >>>>>>>>>> > >>>>>>>>>> @@ -1794,6 +1794,22 @@ static int f2fs_ioc_setflags(struct file *filp, unsigned long arg) > >>>>>>>>>> if (ret) > >>>>>>>>>> goto out; > >>>>>>>>>> > >>>>>>>>>> + if ((fsflags ^ old_fsflags) & FS_NOCOW_FL) { > >>>>>>>>>> + if (!S_ISREG(inode->i_mode)) { > >>>>>>>>>> + ret = -EINVAL; > >>>>>>>>>> + goto out; > >>>>>>>>>> + } > >>>>>>>>>> + > >>>>>>>>>> + if (f2fs_should_update_outplace(inode, NULL)) { > >>>>>>>>>> + ret = -EINVAL; > >>>>>>>>>> + goto out; > >>>>>>>>>> + } > >>>>>>>>>> + > >>>>>>>>>> + ret = f2fs_convert_inline_inode(inode); > >>>>>>>>>> + if (ret) > >>>>>>>>>> + goto out; > >>>>>>>>>> + } > >>>>>>>>>> + > >>>>>>>>>> ret = f2fs_setflags_common(inode, iflags, > >>>>>>>>>> f2fs_fsflags_to_iflags(F2FS_SETTABLE_FS_FL)); > >>>>>>>>>> out: > >>>>>>>>>> -- > >>>>>>>>>> 2.18.0.rc1 > >>>>>>>>> . > >>>>>>>>> > >>>>>>> . > >>>>>>> > >>>>> . > >>>>> > >>> . > >>> > > . > >