Jaegeuk,

Will kernel still hang with this v3?

Thanks,

On 2018/12/19 17:29, 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 <yuch...@huawei.com>
> ---
> v3:
> - introduce f2fs_submit_ipu_bio() to check page Writeback status.
>  fs/f2fs/data.c    | 85 ++++++++++++++++++++++++++++++++++++++++++-----
>  fs/f2fs/f2fs.h    |  3 ++
>  fs/f2fs/segment.c |  5 ++-
>  3 files changed, 84 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index cdfe9a7b856e..e5cd3fd9e215 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -341,20 +341,20 @@ static void __submit_merged_bio(struct f2fs_bio_info 
> *io)
>       io->bio = NULL;
>  }
>  
> -static bool __has_merged_page(struct f2fs_bio_info *io, struct inode *inode,
> +static bool __has_merged_page(struct bio *bio, struct inode *inode,
>                                               struct page *page, nid_t ino)
>  {
>       struct bio_vec *bvec;
>       struct page *target;
>       int i;
>  
> -     if (!io->bio)
> +     if (!bio)
>               return false;
>  
>       if (!inode && !page && !ino)
>               return true;
>  
> -     bio_for_each_segment_all(bvec, io->bio, i) {
> +     bio_for_each_segment_all(bvec, bio, i) {
>  
>               if (bvec->bv_page->mapping)
>                       target = bvec->bv_page;
> @@ -405,7 +405,7 @@ static void __submit_merged_write_cond(struct 
> f2fs_sb_info *sbi,
>                       struct f2fs_bio_info *io = sbi->write_io[btype] + temp;
>  
>                       down_read(&io->io_rwsem);
> -                     ret = __has_merged_page(io, inode, page, ino);
> +                     ret = __has_merged_page(io->bio, inode, page, ino);
>                       up_read(&io->io_rwsem);
>               }
>               if (ret)
> @@ -474,6 +474,59 @@ 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_ipu_bio(struct f2fs_sb_info *sbi, struct bio *bio,
> +                                                     struct page *page)
> +{
> +     if (!__has_merged_page(bio, NULL, page, 0))
> +             return;
> +
> +     if (bio)
> +             __submit_bio(sbi, bio, DATA);
> +}
> +
>  void f2fs_submit_page_write(struct f2fs_io_info *fio)
>  {
>       struct f2fs_sb_info *sbi = fio->sbi;
> @@ -1903,6 +1956,8 @@ 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)
>  {
> @@ -1928,6 +1983,8 @@ 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);
> @@ -2029,6 +2086,10 @@ 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;
>       }
> @@ -2055,7 +2116,7 @@ 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);
>  }
>  
>  /*
> @@ -2071,6 +2132,8 @@ 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;
> @@ -2147,17 +2210,20 @@ static int f2fs_write_cache_pages(struct 
> address_space *mapping,
>                       }
>  
>                       if (PageWriteback(page)) {
> -                             if (wbc->sync_mode != WB_SYNC_NONE)
> +                             if (wbc->sync_mode != WB_SYNC_NONE) {
>                                       f2fs_wait_on_page_writeback(page,
>                                                               DATA, true);
> -                             else
> +                                     f2fs_submit_ipu_bio(sbi, bio, page);
> +                             } else {
>                                       goto continue_unlock;
> +                             }
>                       }
>  
>                       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
> @@ -2206,6 +2272,9 @@ 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 9e56c78fe519..eeede26339a8 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1044,6 +1044,8 @@ 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 */
>  };
>  
> @@ -3105,6 +3107,7 @@ 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 3241e0619275..a361d61b005e 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -3163,7 +3163,10 @@ 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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