Re: [f2fs-dev] [RFC PATHC 2/2] f2fs: apply write hints to select the type of segment for direct write

From: Hyunchul Lee
Date: Sun Nov 12 2017 - 19:07:56 EST


On 11/11/2017 09:38 AM, Chao Yu wrote:
> On 2017/11/9 13:51, Hyunchul Lee wrote:
>> From: Hyunchul Lee <cheol.lee@xxxxxxx>
>>
>> Select the type of the segment using write hints, when blocks are
>> allocated for direct write.
>>
>> There are unhandled corner cases. Hints are not applied in
>> in-place update. And if the blocks of a file is not pre-allocated
>> because of the invalid user buffer, CURSEG_WARM_DATA segment will
>> be selected.
>>
>> Signed-off-by: Hyunchul Lee <cheol.lee@xxxxxxx>
>> ---
>> fs/f2fs/data.c | 101 ++++++++++++++++++++++++++++++++++-----------------------
>> fs/f2fs/f2fs.h | 1 +
>> 2 files changed, 61 insertions(+), 41 deletions(-)
>>
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 36b5352..d06048a 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -783,7 +783,7 @@ struct page *get_new_data_page(struct inode *inode,
>> return page;
>> }
>>
>> -static int __allocate_data_block(struct dnode_of_data *dn)
>> +static int __allocate_data_block(struct dnode_of_data *dn, int seg_type)
>> {
>> struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
>> struct f2fs_summary sum;
>> @@ -808,7 +808,7 @@ static int __allocate_data_block(struct dnode_of_data *dn)
>> set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
>>
>> allocate_data_block(sbi, NULL, dn->data_blkaddr, &dn->data_blkaddr,
>> - &sum, CURSEG_WARM_DATA, NULL, false);
>> + &sum, seg_type, NULL, false);
>> set_data_blkaddr(dn);
>>
>> /* update i_size */
>> @@ -827,42 +827,6 @@ static inline bool __force_buffered_io(struct inode *inode, int rw)
>> F2FS_I_SB(inode)->s_ndevs);
>> }
>>
>> -int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from)
>> -{
>> - struct inode *inode = file_inode(iocb->ki_filp);
>> - struct f2fs_map_blocks map;
>> - int err = 0;
>> -
>> - if (is_inode_flag_set(inode, FI_NO_PREALLOC))
>> - return 0;
>> -
>> - map.m_lblk = F2FS_BLK_ALIGN(iocb->ki_pos);
>> - map.m_len = F2FS_BYTES_TO_BLK(iocb->ki_pos + iov_iter_count(from));
>> - if (map.m_len > map.m_lblk)
>> - map.m_len -= map.m_lblk;
>> - else
>> - map.m_len = 0;
>> -
>> - map.m_next_pgofs = NULL;
>> -
>> - if (iocb->ki_flags & IOCB_DIRECT) {
>> - err = f2fs_convert_inline_inode(inode);
>> - if (err)
>> - return err;
>> - return f2fs_map_blocks(inode, &map, 1,
>> - __force_buffered_io(inode, WRITE) ?
>> - F2FS_GET_BLOCK_PRE_AIO :
>> - F2FS_GET_BLOCK_PRE_DIO);
>> - }
>> - if (iocb->ki_pos + iov_iter_count(from) > MAX_INLINE_DATA(inode)) {
>> - err = f2fs_convert_inline_inode(inode);
>> - if (err)
>> - return err;
>> - }
>> - if (!f2fs_has_inline_data(inode))
>> - return f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_AIO);
>> - return err;
>> -}
>>
>> static inline void __do_map_lock(struct f2fs_sb_info *sbi, int flag, bool lock)
>> {
>> @@ -888,8 +852,8 @@ static inline void __do_map_lock(struct f2fs_sb_info *sbi, int flag, bool lock)
>> * b. do not use extent cache for better performance
>> * c. give the block addresses to blockdev
>> */
>> -int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>> - int create, int flag)
>> +static int __f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>> + int create, int flag, int seg_type)
>> {
>> unsigned int maxblocks = map->m_len;
>> struct dnode_of_data dn;
>> @@ -957,7 +921,12 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>> last_ofs_in_node = dn.ofs_in_node;
>> }
>> } else {
>> - err = __allocate_data_block(&dn);
>> + /* if this inode is marked with FI_NO_PREALLOC,
>> + * @seg_type is NO_CHECK_TYPE
>> + */
>> + if (seg_type == NO_CHECK_TYPE)
>> + seg_type = CURSEG_WARM_DATA;
>> + err = __allocate_data_block(&dn, seg_type);
>
> We need to use inode.i_write_hint instead of ki_hint passed from file.f_write_hint?
>

The following commit says to use file.f_write_hint if it is available.
"c75b1d9 fs: add fcntl() interface for setting/getting write life time hints"

And ki_hint is assiged to file.f_write_hint or inode.i_write_hint
by file_write_hint() in init_sync_kiocb().
So, I think we need to use ki_hint instead of inode.i_write_hint.

Thanks

> Thanks,
>
>> if (!err)
>> set_inode_flag(inode, FI_APPEND_WRITE);
>> }
>> @@ -1048,6 +1017,51 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>> return err;
>> }
>>
>> +int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>> + int create, int flag)
>> +{
>> + return __f2fs_map_blocks(inode, map, create, flag, NO_CHECK_TYPE);
>> +}
>> +
>> +int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from)
>> +{
>> + struct inode *inode = file_inode(iocb->ki_filp);
>> + struct f2fs_map_blocks map;
>> + int err = 0;
>> +
>> + if (is_inode_flag_set(inode, FI_NO_PREALLOC))
>> + return 0;
>> +
>> + map.m_lblk = F2FS_BLK_ALIGN(iocb->ki_pos);
>> + map.m_len = F2FS_BYTES_TO_BLK(iocb->ki_pos + iov_iter_count(from));
>> + if (map.m_len > map.m_lblk)
>> + map.m_len -= map.m_lblk;
>> + else
>> + map.m_len = 0;
>> +
>> + map.m_next_pgofs = NULL;
>> +
>> + if (iocb->ki_flags & IOCB_DIRECT) {
>> + err = f2fs_convert_inline_inode(inode);
>> + if (err)
>> + return err;
>> + return __f2fs_map_blocks(inode, &map, 1,
>> + __force_buffered_io(inode, WRITE) ?
>> + F2FS_GET_BLOCK_PRE_AIO :
>> + F2FS_GET_BLOCK_PRE_DIO,
>> + rw_hint_to_seg_type(iocb->ki_hint));
>> + }
>> + if (iocb->ki_pos + iov_iter_count(from) > MAX_INLINE_DATA(inode)) {
>> + err = f2fs_convert_inline_inode(inode);
>> + if (err)
>> + return err;
>> + }
>> + if (!f2fs_has_inline_data(inode))
>> + return f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_AIO);
>> +
>> + return err;
>> +}
>> +
>> static int __get_data_block(struct inode *inode, sector_t iblock,
>> struct buffer_head *bh, int create, int flag,
>> pgoff_t *next_pgofs)
>> @@ -2082,6 +2096,11 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>>
>> trace_f2fs_direct_IO_enter(inode, offset, count, rw);
>>
>> + /* This is for avoiding the situation that the data of a segment is
>> + * passed down to devices with different hints
>> + */
>> + iocb->ki_hint = WRITE_LIFE_NOT_SET;
>> +
>> down_read(&F2FS_I(inode)->dio_rwsem[rw]);
>> err = blockdev_direct_IO(iocb, inode, iter, get_data_block_dio);
>> up_read(&F2FS_I(inode)->dio_rwsem[rw]);
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 4b4a72f..9be5658 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -2562,6 +2562,7 @@ int lookup_journal_in_cursum(struct f2fs_journal *journal, int type,
>> void destroy_segment_manager(struct f2fs_sb_info *sbi);
>> int __init create_segment_manager_caches(void);
>> void destroy_segment_manager_caches(void);
>> +int rw_hint_to_seg_type(enum rw_hint hint);
>>
>> /*
>> * checkpoint.c
>>
>