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Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Subject: Re: [PATCH] f2fs: compress: don't force buffered io when in COMPR_MODE_USER mode To: Chao Yu , Jaegeuk Kim Cc: Qi Han , linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org References: <20230609131555.56651-1-frank.li@vivo.com> <8097d4d9-815e-2527-0fb7-90ec0609a4a3@kernel.org> <7ab6b6f9-37fa-9bf2-69ce-7b1b1944d9f3@kernel.org> <65ce42d6-889a-5e1d-8f04-af8f66fd0afa@kernel.org> From: Yangtao Li In-Reply-To: <65ce42d6-889a-5e1d-8f04-af8f66fd0afa@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: SGXP274CA0023.SGPP274.PROD.OUTLOOK.COM (2603:1096:4:b8::35) To SEZPR06MB5269.apcprd06.prod.outlook.com (2603:1096:101:78::6) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SEZPR06MB5269:EE_|SEZPR06MB5591:EE_ X-MS-Office365-Filtering-Correlation-Id: 0d94bb1a-4d60-45d4-ef92-08db70a7fefb X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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In fact, when the file is not compressed, we don't >>>>>> need >>>>>> to force it to buffer io. >>>>>> >>>>>>                    | w/o patch | w/ patch | >>>>>> seq read  (MB/s) | 1320.068  | 3696.154 | >>>>>> seq write (MB/s) | 617.996   | 2978.478 | >>>>>> >>>>>> Fixes: 4c8ff7095bef ("f2fs: support data compression") >>>>>> Signed-off-by: Qi Han >>>>>> Signed-off-by: Yangtao Li >>>>>> --- >>>>>>    fs/f2fs/f2fs.h | 14 ++++++++++++++ >>>>>>    fs/f2fs/file.c |  2 +- >>>>>>    2 files changed, 15 insertions(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >>>>>> index 1efcfd9e5a99..7f5472525310 100644 >>>>>> --- a/fs/f2fs/f2fs.h >>>>>> +++ b/fs/f2fs/f2fs.h >>>>>> @@ -3168,6 +3168,20 @@ static inline int f2fs_compressed_file(struct >>>>>> inode *inode) >>>>>>            is_inode_flag_set(inode, FI_COMPRESSED_FILE); >>>>>>    } >>>>>>    +static inline bool f2fs_is_compressed_file(struct inode *inode) >>>>>> +{ >>>>>> +    int compress_mode = >>>>>> F2FS_OPTION(F2FS_I_SB(inode)).compress_mode; >>>>>> + >>>>>> +    if (compress_mode == COMPR_MODE_FS) >>>>>> +        return f2fs_compressed_file(inode); >>>>>> +    else if (atomic_read(&F2FS_I(inode)->i_compr_blocks) || >>>>> >>>>> Should check dirty page as well? i_compr_blocks may increase after >>>>> data writeback. >>>>> >>>> IIUC, in COMPR_MODE_USER mode, i_compr_blocks will only be updated >>>> when >>>> FI_ENABLE_COMPRESS is enabled. >>>> >>>> If FI_ENABLE_COMPRESS is not enabled, i_compr_blocks will never be >>>> updated after data writeback. >>>> >>>> So there is no need to additionally judge whether there is a dirty >>>> page? >>> >>> Oh, user mode, that's correct. >>> >>> If we allow dio/aio on compress file, it needs to consider race case in >>> between aio and ioc_compress_file. >> >> >> The inode_lock is already held in f2fs_file_write_iter and >> f2fs_ioc_compress_file, I guess this is enough? >> >> What else? > > aio may complete outside inode lock, so it needs to call inode_dio_wait() > in f2fs_ioc_compress_file() to avoid the race case? How about adding this below？ diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index f45d05c13ae5..5021d13e788b 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -4146,6 +4146,10 @@ static int f2fs_ioc_compress_file(struct file *filp)                 goto out;         } +       /* avoid race case between aio and ioc_compress_file */ +       if (F2FS_OPTION(sbi).compress_mode == COMPR_MODE_USER) +               inode_dio_wait(inode); +         ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);         if (ret)                 goto out; Thanks, > > Thanks, > >> >> >> 4691 static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct >> iov_iter *from) >> 4692 { >> 4693         struct inode *inode = file_inode(iocb->ki_filp); >> 4694         const loff_t orig_pos = iocb->ki_pos; >> 4695         const size_t orig_count = iov_iter_count(from); >> 4696         loff_t target_size; >> 4697         bool dio; >> 4698         bool may_need_sync = true; >> 4699         int preallocated; >> 4700         ssize_t ret; >> 4701 >> 4702         if (unlikely(f2fs_cp_error(F2FS_I_SB(inode)))) { >> 4703                 ret = -EIO; >> 4704                 goto out; >> 4705         } >> 4706 >> 4707         if (!f2fs_is_compress_backend_ready(inode)) { >> 4708                 ret = -EOPNOTSUPP; >> 4709                 goto out; >> 4710         } >> 4711 >> 4712         if (iocb->ki_flags & IOCB_NOWAIT) { >> 4713                 if (!inode_trylock(inode)) { >> 4714                         ret = -EAGAIN; >> 4715                         goto out; >> 4716                 } >> 4717         } else { >> 4718                 inode_lock(inode); >> 4719         } >> >> >> 4115 static int f2fs_ioc_compress_file(struct file *filp) >> 4116 { >> 4117         struct inode *inode = file_inode(filp); >> 4118         struct f2fs_sb_info *sbi = F2FS_I_SB(inode); >> 4119         pgoff_t page_idx = 0, last_idx; >> 4120         unsigned int blk_per_seg = sbi->blocks_per_seg; >> 4121         int cluster_size = F2FS_I(inode)->i_cluster_size; >> 4122         int count, ret; >> 4123 >> 4124         if (!f2fs_sb_has_compression(sbi) || >> 4125                         F2FS_OPTION(sbi).compress_mode != >> COMPR_MODE_USER) >> 4126                 return -EOPNOTSUPP; >> 4127 >> 4128         if (!(filp->f_mode & FMODE_WRITE)) >> 4129                 return -EBADF; >> 4130 >> 4131         if (!f2fs_compressed_file(inode)) >> 4132                 return -EINVAL; >> 4133 >> 4134         f2fs_balance_fs(sbi, true); >> 4135 >> 4136         file_start_write(filp); >> 4137         inode_lock(inode); >> >> >> Thanks, >> >>> >>> Thanks, >>> >>>> >>>> >>>> Thanks, >>>> >>>>> Thanks, >>>>> >>>>>> +        is_inode_flag_set(inode, FI_COMPRESS_RELEASED) || >>>>>> +        is_inode_flag_set(inode, FI_ENABLE_COMPRESS)) >>>>>> +        return true; >>>>>> + >>>>>> +    return false; >>>>>> +} >>>>>> + >>>>>>    static inline bool f2fs_need_compress_data(struct inode *inode) >>>>>>    { >>>>>>        int compress_mode = >>>>>> F2FS_OPTION(F2FS_I_SB(inode)).compress_mode; >>>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >>>>>> index 74ecc9e20619..0698129b2165 100644 >>>>>> --- a/fs/f2fs/file.c >>>>>> +++ b/fs/f2fs/file.c >>>>>> @@ -821,7 +821,7 @@ static bool f2fs_force_buffered_io(struct inode >>>>>> *inode, int rw) >>>>>>            return true; >>>>>>        if (fsverity_active(inode)) >>>>>>            return true; >>>>>> -    if (f2fs_compressed_file(inode)) >>>>>> +    if (f2fs_is_compressed_file(inode)) >>>>>>            return true; >>>>>>          /* disallow direct IO if any of devices has unaligned >>>>>> blksize */