linux-kernel - Re: [PATCH] f2fs: separate IPU policy for fdatasync from F2FS_IPU

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Date:   Wed, 2 Nov 2022 20:25:18 +0800
From:   qixiaoyu <qxy65535@...il.com>
To:     Chao Yu <chao@...nel.org>
Cc:     qixiaoyu1 <qixiaoyu1@...omi.com>, linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [PATCH] f2fs: separate IPU policy for fdatasync from
 F2FS_IPU_FSYNC

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:

                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@...omi.com>
> >---
> >  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);