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Message-ID: <fe223231-5445-61ef-1ba8-0d46f4f4ed5f@vivo.com>
Date: Mon, 19 Jun 2023 11:11:47 +0800
From: Yangtao Li <frank.li@...o.com>
To: Chao Yu <chao@...nel.org>, Jaegeuk Kim <jaegeuk@...nel.org>
Cc: Qi Han <hanqi@...o.com>, linux-f2fs-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] f2fs: compress: don't force buffered io when in
COMPR_MODE_USER mode
On 2023/6/19 8:54, Chao Yu wrote:
> On 2023/6/13 12:14, Yangtao Li wrote:
>>
>> On 2023/6/12 22:38, Chao Yu wrote:
>>> On 2023/6/9 21:15, Yangtao Li wrote:
>>>> It is observed that when in user compression mode
>>>> (compress_extension=*),
>>>> even though the file is not compressed, the file is still forced to
>>>> use
>>>> buffer io, which makes the AndroBench sequential read and write drop
>>>> significantly. 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 <hanqi@...o.com>
>>>> Signed-off-by: Yangtao Li <frank.li@...o.com>
>>>> ---
>>>> 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?
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 */
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