Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [f2fs-dev] [PATCH] f2fs: add bio cache for IPU
From:   Chao Yu <yuchao0@huawei.com>
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>
References: <20181023083817.3466-1-yuchao0@huawei.com>
 <20181115075226.GA83610@jaegeuk-macbookpro.roam.corp.google.com>
 <944355f6-49d8-f579-aad6-53c54258e90b@huawei.com>
Message-ID: <0fcfcec5-7b09-603e-f8b7-1c6346dc17b3@huawei.com>
Date:   Fri, 16 Nov 2018 17:46:19 +0800
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <944355f6-49d8-f579-aad6-53c54258e90b@huawei.com>
Content-Type: text/plain; charset="windows-1252"
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Jaegeuk,

On 2018/11/15 16:32, Chao Yu wrote:
> Hi Jaeguek,
> 
> On 2018/11/15 15:52, Jaegeuk Kim wrote:
>> Hi Chao,
>>
>> I suspect this brings a system stuck by missing bio being flushed. Please check
>> the changes.
> 
> Oh, let me check this patch.

I found one corner case below, but not very sure it can avoid system stuck.

	if (unlikely(f2fs_cp_error(sbi))) {
		if (bio && *bio) {
			__submit_bio(sbi, *bio, DATA);
			*bio = NULL;
		}
		f2fs_submit_merged_write(sbi, DATA);
		submitted = NULL;
	}

Anyway, let me send v2, could you please test this?

Thanks,

> 
> Thanks,
> 
>>
>> Thanks,
>>
>> On 10/23, 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>
>>> ---
>>>  fs/f2fs/data.c    | 57 +++++++++++++++++++++++++++++++++++++++++++++--
>>>  fs/f2fs/f2fs.h    |  3 +++
>>>  fs/f2fs/segment.c |  5 ++++-
>>>  3 files changed, 62 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index 01b7f59523dc..0c8f18dc140d 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -491,6 +491,49 @@ 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;
>>> @@ -1899,6 +1942,8 @@ 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)
>>>  {
>>> @@ -1924,6 +1969,8 @@ 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);
>>> @@ -2051,7 +2098,7 @@ 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);
>>>  }
>>>  
>>>  /*
>>> @@ -2067,6 +2114,8 @@ 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;
>>> @@ -2154,7 +2203,8 @@ 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
>>> @@ -2201,6 +2251,9 @@ 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 8932276015f9..6af2a105529d 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -1042,6 +1042,8 @@ 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 */
>>>  };
>>>  
>>> @@ -3085,6 +3087,7 @@ 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 3aa2f00262b3..b51b182dd7f4 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -3194,7 +3194,10 @@ 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);
>>>  
>>> -- 
>>> 2.18.0.rc1
>>
>> .
>>
> 
> 
> 
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> 
> .
>