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Date:   Tue, 18 Dec 2018 16:45:35 -0800
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <yuchao0@huawei.com>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: add bio cache for IPU
Message-ID: <20181219004535.GA46286@jaegeuk-macbookpro.roam.corp.google.com>
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 <ba61f507-a209-76c9-a10e-c847b07caf40@huawei.com>
 <20181214143656.GB75922@jaegeuk-macbookpro.roam.corp.google.com>
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On 12/14, Jaegeuk Kim wrote:
> On 12/14, Chao Yu wrote:
> > Hi Jaegeuk,
> > 
> > I guess ("f2fs: clear PG_writeback if IPU failed") and v2 patch can fix
> > hang issue caused by v1 one, could you please have a try with v2?
> 
> Sure.

Hang again. I'll remove this patch and run the test again without this to
confirm.

> 
> > 
> > Thanks,
> > 
> > On 2018/11/19 11:29, Chao Yu wrote:
> > > SQLite in Wal mode may trigger sequential IPU write in db-wal file, after
> > > commit d1b3e72d5490 ("f2fs: submit bio of in-place-update pages"), we
> > > lost the chance of merging page in inner managed bio cache, result in
> > > submitting more small-sized IO.
> > > 
> > > So let's add temporary bio in writepages() to cache mergeable write IO as
> > > much as possible.
> > > 
> > > Test case:
> > > 1. xfs_io -f /mnt/f2fs/file -c "pwrite 0 65536" -c "fsync"
> > > 2. xfs_io -f /mnt/f2fs/file -c "pwrite 0 65536" -c "fsync"
> > > 
> > > Before:
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65544, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65552, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65560, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65568, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65576, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65584, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65592, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65600, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65608, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65616, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65624, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65632, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65640, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65648, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65656, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65664, size = 4096
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), NODE, sector = 57352, size = 4096
> > > 
> > > After:
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65544, size = 65536
> > > f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), NODE, sector = 57368, size = 4096
> > > 
> > > Signed-off-by: Chao Yu <yuchao0@huawei.com>
> > > ---
> > > v2:
> > > - submit cached bio for cp error case.
> > >  fs/f2fs/data.c    | 61 +++++++++++++++++++++++++++++++++++++++++++++--
> > >  fs/f2fs/f2fs.h    |  3 +++
> > >  fs/f2fs/segment.c |  5 +++-
> > >  3 files changed, 66 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > index 8780f3d737c4..7dffafb8b2c5 100644
> > > --- a/fs/f2fs/data.c
> > > +++ b/fs/f2fs/data.c
> > > @@ -474,6 +474,49 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
> > >  	return 0;
> > >  }
> > >  
> > > +int f2fs_merge_page_bio(struct f2fs_io_info *fio)
> > > +{
> > > +	struct bio *bio = *fio->bio;
> > > +	struct page *page = fio->encrypted_page ?
> > > +			fio->encrypted_page : fio->page;
> > > +
> > > +	if (!f2fs_is_valid_blkaddr(fio->sbi, fio->new_blkaddr,
> > > +			__is_meta_io(fio) ? META_GENERIC : DATA_GENERIC))
> > > +		return -EFAULT;
> > > +
> > > +	trace_f2fs_submit_page_bio(page, fio);
> > > +	f2fs_trace_ios(fio, 0);
> > > +
> > > +	if (bio && (*fio->last_block + 1 != fio->new_blkaddr ||
> > > +			!__same_bdev(fio->sbi, fio->new_blkaddr, bio))) {
> > > +		__submit_bio(fio->sbi, bio, fio->type);
> > > +		bio = NULL;
> > > +	}
> > > +alloc_new:
> > > +	if (!bio) {
> > > +		bio = __bio_alloc(fio->sbi, fio->new_blkaddr, fio->io_wbc,
> > > +				BIO_MAX_PAGES, false, fio->type, fio->temp);
> > > +		*fio->last_block = fio->new_blkaddr;
> > > +		bio_set_op_attrs(bio, fio->op, fio->op_flags);
> > > +	}
> > > +
> > > +	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
> > > +		__submit_bio(fio->sbi, bio, fio->type);
> > > +		bio = NULL;
> > > +		goto alloc_new;
> > > +	}
> > > +
> > > +	if (fio->io_wbc)
> > > +		wbc_account_io(fio->io_wbc, page, PAGE_SIZE);
> > > +
> > > +	*fio->last_block = fio->new_blkaddr;
> > > +
> > > +	inc_page_count(fio->sbi, WB_DATA_TYPE(fio->page));
> > > +
> > > +	*fio->bio = bio;
> > > +	return 0;
> > > +}
> > > +
> > >  void f2fs_submit_page_write(struct f2fs_io_info *fio)
> > >  {
> > >  	struct f2fs_sb_info *sbi = fio->sbi;
> > > @@ -1894,6 +1937,8 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fio)
> > >  }
> > >  
> > >  static int __write_data_page(struct page *page, bool *submitted,
> > > +				struct bio **bio,
> > > +				sector_t *last_block,
> > >  				struct writeback_control *wbc,
> > >  				enum iostat_type io_type)
> > >  {
> > > @@ -1919,6 +1964,8 @@ static int __write_data_page(struct page *page, bool *submitted,
> > >  		.need_lock = LOCK_RETRY,
> > >  		.io_type = io_type,
> > >  		.io_wbc = wbc,
> > > +		.bio = bio,
> > > +		.last_block = last_block,
> > >  	};
> > >  
> > >  	trace_f2fs_writepage(page, DATA);
> > > @@ -2020,6 +2067,10 @@ static int __write_data_page(struct page *page, bool *submitted,
> > >  		f2fs_balance_fs(sbi, need_balance_fs);
> > >  
> > >  	if (unlikely(f2fs_cp_error(sbi))) {
> > > +		if (bio && *bio) {
> > > +			__submit_bio(sbi, *bio, DATA);
> > > +			*bio = NULL;
> > > +		}
> > >  		f2fs_submit_merged_write(sbi, DATA);
> > >  		submitted = NULL;
> > >  	}
> > > @@ -2046,7 +2097,7 @@ static int __write_data_page(struct page *page, bool *submitted,
> > >  static int f2fs_write_data_page(struct page *page,
> > >  					struct writeback_control *wbc)
> > >  {
> > > -	return __write_data_page(page, NULL, wbc, FS_DATA_IO);
> > > +	return __write_data_page(page, NULL, NULL, NULL, wbc, FS_DATA_IO);
> > >  }
> > >  
> > >  /*
> > > @@ -2062,6 +2113,8 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> > >  	int done = 0;
> > >  	struct pagevec pvec;
> > >  	struct f2fs_sb_info *sbi = F2FS_M_SB(mapping);
> > > +	struct bio *bio = NULL;
> > > +	sector_t last_block;
> > >  	int nr_pages;
> > >  	pgoff_t uninitialized_var(writeback_index);
> > >  	pgoff_t index;
> > > @@ -2149,7 +2202,8 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> > >  			if (!clear_page_dirty_for_io(page))
> > >  				goto continue_unlock;
> > >  
> > > -			ret = __write_data_page(page, &submitted, wbc, io_type);
> > > +			ret = __write_data_page(page, &submitted, &bio,
> > > +						&last_block, wbc, io_type);
> > >  			if (unlikely(ret)) {
> > >  				/*
> > >  				 * keep nr_to_write, since vfs uses this to
> > > @@ -2198,6 +2252,9 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> > >  	if (nwritten)
> > >  		f2fs_submit_merged_write_cond(F2FS_M_SB(mapping), mapping->host,
> > >  								NULL, 0, DATA);
> > > +	/* submit cached bio of IPU write */
> > > +	if (bio)
> > > +		__submit_bio(sbi, bio, DATA);
> > >  
> > >  	return ret;
> > >  }
> > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > > index 26ad1de8641c..d0bb679fd668 100644
> > > --- a/fs/f2fs/f2fs.h
> > > +++ b/fs/f2fs/f2fs.h
> > > @@ -1051,6 +1051,8 @@ struct f2fs_io_info {
> > >  	bool retry;		/* need to reallocate block address */
> > >  	enum iostat_type io_type;	/* io type */
> > >  	struct writeback_control *io_wbc; /* writeback control */
> > > +	struct bio **bio;		/* bio for ipu */
> > > +	sector_t *last_block;		/* last block number in bio */
> > >  	unsigned char version;		/* version of the node */
> > >  };
> > >  
> > > @@ -3093,6 +3095,7 @@ void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi,
> > >  				nid_t ino, enum page_type type);
> > >  void f2fs_flush_merged_writes(struct f2fs_sb_info *sbi);
> > >  int f2fs_submit_page_bio(struct f2fs_io_info *fio);
> > > +int f2fs_merge_page_bio(struct f2fs_io_info *fio);
> > >  void f2fs_submit_page_write(struct f2fs_io_info *fio);
> > >  struct block_device *f2fs_target_device(struct f2fs_sb_info *sbi,
> > >  			block_t blk_addr, struct bio *bio);
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index 204d31e58967..b0e6331a5d95 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -3158,7 +3158,10 @@ int f2fs_inplace_write_data(struct f2fs_io_info *fio)
> > >  
> > >  	stat_inc_inplace_blocks(fio->sbi);
> > >  
> > > -	err = f2fs_submit_page_bio(fio);
> > > +	if (fio->bio)
> > > +		err = f2fs_merge_page_bio(fio);
> > > +	else
> > > +		err = f2fs_submit_page_bio(fio);
> > >  	if (!err)
> > >  		update_device_state(fio);
> > >  
> > > 
> 
> 
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