Re: [PATCH] f2fs: separate IPU policy for fdatasync from F2FS_IPU_FSYNC

[qixiaoyu]

On Sun, Nov 06, 2022 at 09:54:59PM +0800, Chao Yu wrote:
> On 2022/11/2 20:25, qixiaoyu wrote:
> >Hi Chao,
> >
> >fdatasync do in-place-update to avoid additional node writes, but currently
> >it only do that with F2FS_IPU_FSYNC as:
> >
> >f2fs_do_sync_file:
> >	if (datasync || get_dirty_pages(inode) <= SM_I(sbi)->min_fsync_blocks)
> >  		set_inode_flag(inode, FI_NEED_IPU);
> >
> >check_inplace_update_policy:
> >	/* this is only set during fdatasync */
> >	if (policy & (0x1 << F2FS_IPU_FSYNC) &&
> >			is_inode_flag_set(inode, FI_NEED_IPU))
> >		return true;
> >
> >So this patch separate in-place-update of fdatasync from F2FS_IPU_FSYNC to
> >apply it to all IPU policy.
> >
> >BTW, we found small performance improvement with this patch on AndroBench app
> >using F2FS_IPU_SSR_UTIL on our product:
> 
> How this patch affects performance when F2FS_IPU_SSR_UTIL is on?
> 
> Thanks,
> 

SQLite test in AndroBench app use fdatasync to sync file to the disk.
When switch to F2FS_IPU_SSR_UTIL ipu_policy, it will use out-of-place-update
even though SQLite calls fdatasync, which will introduce extra meta data write.

Thanks.

> >
> >                 F2FS_IPU_FSYNC  F2FS_IPU_SSR_UTIL   F2FS_IPU_SSR_UTIL(with patch)
> >SQLite Insert(QPS)  6818.08     6327.09(-7.20%)     6757.72
> >SQLite Update(QPS)  6528.81     6336.57(-2.94%)     6490.77
> >SQLite Delete(QPS)  9724.68     9378.37(-3.56%)     9622.27
> >
> >Thanks
> >
> >On Tue, Nov 01, 2022 at 11:14:55PM +0800, Chao Yu wrote:
> >>On 2022/10/21 10:31, qixiaoyu1 wrote:
> >>>Currently IPU policy for fdatasync is coupled with F2FS_IPU_FSYNC.
> >>>Fix to apply it to all IPU policy.
> >>
> >>Xiaoyu,
> >>
> >>Sorry for the delay.
> >>
> >>I didn't get the point, can you please explain more about the
> >>issue?
> >>
> >>Thanks,
> >>
> >>>
> >>>Signed-off-by: qixiaoyu1 <qixiaoyu1@xxxxxxxxxx>
> >>>---
> >>>  fs/f2fs/data.c | 8 +++-----
> >>>  fs/f2fs/file.c | 4 +++-
> >>>  2 files changed, 6 insertions(+), 6 deletions(-)
> >>>
> >>>diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> >>>index a71e818cd67b..fec8e15fe820 100644
> >>>--- a/fs/f2fs/data.c
> >>>+++ b/fs/f2fs/data.c
> >>>@@ -2518,6 +2518,9 @@ static inline bool check_inplace_update_policy(struct inode *inode,
> >>>  	if (policy & (0x1 << F2FS_IPU_HONOR_OPU_WRITE) &&
> >>>  			is_inode_flag_set(inode, FI_OPU_WRITE))
> >>>  		return false;
> >>>+	/* this is set by fdatasync or F2FS_IPU_FSYNC policy */
> >>>+	if (is_inode_flag_set(inode, FI_NEED_IPU))
> >>>+		return true;
> >>>  	if (policy & (0x1 << F2FS_IPU_FORCE))
> >>>  		return true;
> >>>  	if (policy & (0x1 << F2FS_IPU_SSR) && f2fs_need_SSR(sbi))
> >>>@@ -2538,11 +2541,6 @@ static inline bool check_inplace_update_policy(struct inode *inode,
> >>>  			!IS_ENCRYPTED(inode))
> >>>  		return true;
> >>>-	/* this is only set during fdatasync */
> >>>-	if (policy & (0x1 << F2FS_IPU_FSYNC) &&
> >>>-			is_inode_flag_set(inode, FI_NEED_IPU))
> >>>-		return true;
> >>>-
> >>>  	if (unlikely(fio && is_sbi_flag_set(sbi, SBI_CP_DISABLED) &&
> >>>  			!f2fs_is_checkpointed_data(sbi, fio->old_blkaddr)))
> >>>  		return true;
> >>>diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> >>>index 82cda1258227..08091550cdf2 100644
> >>>--- a/fs/f2fs/file.c
> >>>+++ b/fs/f2fs/file.c
> >>>@@ -270,8 +270,10 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
> >>>  		goto go_write;
> >>>  	/* if fdatasync is triggered, let's do in-place-update */
> >>>-	if (datasync || get_dirty_pages(inode) <= SM_I(sbi)->min_fsync_blocks)
> >>>+	if (datasync || (SM_I(sbi)->ipu_policy & (0x1 << F2FS_IPU_FSYNC) &&
> >>>+			get_dirty_pages(inode) <= SM_I(sbi)->min_fsync_blocks))
> >>>  		set_inode_flag(inode, FI_NEED_IPU);
> >>>+
> >>>  	ret = file_write_and_wait_range(file, start, end);
> >>>  	clear_inode_flag(inode, FI_NEED_IPU);