Re: [f2fs-dev] [PATCH 1/3] f2fs: support passing down write hints given by users to block layer

[Hyunchul Lee]

On 01/25/2018 05:01 PM, Chao Yu wrote:
> Hi Hyunchul,
> 
> On 2018/1/25 10:47, Hyunchul Lee wrote:
>> Hi Chao,
>>
>> On 01/25/2018 12:32 AM, Chao Yu wrote:
>>> On 2018/1/22 18:49, Hyunchul Lee wrote:
>>>> From: Hyunchul Lee <cheol.lee@xxxxxxx>
>>>>
>>>> Add the 'whint_mode' mount option that controls which write
>>>> hints are passed down to block layer. There are "off" and
>>>> "user-based" mode. The default mode is "off".
>>>>
>>>> 1) whint_mode=user-based. F2FS tries to pass down hints given
>>>> by users.
>>>
>>> Minor,
>>>
>>> 1) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET
>>>
>>> 2) whint_mode=user-based. F2FS tries to pass down hints given by users.
>>> ...
>>>
>>
>> Okay, I will reflect this.
>>
>>> How about changing all comments and codes with above order?
>>>
>>>>
>>>> User                  F2FS                     Block
>>>> ----                  ----                     -----
>>>>                       META                     WRITE_LIFE_NOT_SET
>>>>                       HOT_NODE                 "
>>>>                       WARM_NODE                "
>>>>                       COLD_NODE                "
>>>> ioctl(COLD)           COLD_DATA                WRITE_LIFE_EXTREME
>>>> extension list        "                        "
>>>>
>>>> -- buffered io
>>>> WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
>>>> WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
>>>> WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_NOT_SET
>>>> WRITE_LIFE_NONE       "                        "
>>>> WRITE_LIFE_MEDIUM     "                        "
>>>> WRITE_LIFE_LONG       "                        "
>>>>
>>>> -- direct io
>>>> WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
>>>> WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
>>>> WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_NOT_SET
>>>> WRITE_LIFE_NONE       "                        WRITE_LIFE_NONE
>>>> WRITE_LIFE_MEDIUM     "                        WRITE_LIFE_MEDIUM
>>>> WRITE_LIFE_LONG       "                        WRITE_LIFE_LONG
>>>>
>>>> 2) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET.
>>>>
>>>> Many thanks to Chao Yu and Jaegeuk Kim for comments to
>>>> implement this patch.
>>>>
>>>> Signed-off-by: Hyunchul Lee <cheol.lee@xxxxxxx>
>>>> ---
>>>>  fs/f2fs/data.c    | 27 ++++++++++++++++++++-----
>>>>  fs/f2fs/f2fs.h    |  9 +++++++++
>>>>  fs/f2fs/segment.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>  fs/f2fs/super.c   | 24 +++++++++++++++++++++-
>>>>  4 files changed, 113 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>>> index 6cba74e..c76ddc2 100644
>>>> --- a/fs/f2fs/data.c
>>>> +++ b/fs/f2fs/data.c
>>>> @@ -175,15 +175,22 @@ static bool __same_bdev(struct f2fs_sb_info *sbi,
>>>>   */
>>>>  static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
>>>>  				struct writeback_control *wbc,
>>>> -				int npages, bool is_read)
>>>> +				int npages, bool is_read,
>>>> +				enum page_type type, enum temp_type temp)
>>>>  {
>>>>  	struct bio *bio;
>>>>  
>>>>  	bio = f2fs_bio_alloc(sbi, npages, true);
>>>>  
>>>>  	f2fs_target_device(sbi, blk_addr, bio);
>>>> -	bio->bi_end_io = is_read ? f2fs_read_end_io : f2fs_write_end_io;
>>>> -	bio->bi_private = is_read ? NULL : sbi;
>>>> +	if (is_read) {
>>>> +		bio->bi_end_io = f2fs_read_end_io;
>>>> +		bio->bi_private = NULL;
>>>> +	} else {
>>>> +		bio->bi_end_io = f2fs_write_end_io;
>>>> +		bio->bi_private = sbi;
>>>> +		bio->bi_write_hint = io_type_to_rw_hint(sbi, type, temp);
>>>> +	}
>>>>  	if (wbc)
>>>>  		wbc_init_bio(wbc, bio);
>>>>  
>>>> @@ -382,7 +389,7 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
>>>>  
>>>>  	/* Allocate a new bio */
>>>>  	bio = __bio_alloc(fio->sbi, fio->new_blkaddr, fio->io_wbc,
>>>> -				1, is_read_io(fio->op));
>>>> +				1, is_read_io(fio->op), fio->type, fio->temp);
>>>>  
>>>>  	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
>>>>  		bio_put(bio);
>>>> @@ -445,7 +452,8 @@ int f2fs_submit_page_write(struct f2fs_io_info *fio)
>>>>  			goto out_fail;
>>>>  		}
>>>>  		io->bio = __bio_alloc(sbi, fio->new_blkaddr, fio->io_wbc,
>>>> -						BIO_MAX_PAGES, false);
>>>> +						BIO_MAX_PAGES, false,
>>>> +						fio->type, fio->temp);
>>>>  		io->fio = *fio;
>>>>  	}
>>>>  
>>>> @@ -2287,10 +2295,12 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>>>>  {
>>>>  	struct address_space *mapping = iocb->ki_filp->f_mapping;
>>>>  	struct inode *inode = mapping->host;
>>>> +	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>>  	size_t count = iov_iter_count(iter);
>>>>  	loff_t offset = iocb->ki_pos;
>>>>  	int rw = iov_iter_rw(iter);
>>>>  	int err;
>>>> +	enum rw_hint hint;
>>>>  
>>>>  	err = check_direct_IO(inode, iter, offset);
>>>>  	if (err)
>>>> @@ -2301,11 +2311,18 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>>>>  
>>>>  	trace_f2fs_direct_IO_enter(inode, offset, count, rw);
>>>>  
>>>> +	if (rw == WRITE && sbi->whint_mode == WHINT_MODE_OFF) {
>>>> +		hint = iocb->ki_hint;
>>>> +		iocb->ki_hint = WRITE_LIFE_NOT_SET;
>>>> +	}
>>>
>>> In f2fs_preallocate_blocks, we should wrap original iocb->ki_hint with
>>> WRITE_LIFE_NOT_SET under WHINT_MODE_OFF mode?
>>>
>> In f2fs_preallocate_blocks, we should keep the original iocb->ki_hint to 
>> select proper segments. So I think f2fs_direct_IO is the best place
>> before submiting io.
> 
> Oh, right.
> 
> How about using temporary variable to store sbi->whint_mode? so that we
> won't be affected by sbi->whint_mode changing.
> 

Yes, We need this.

> And could you please check to make sure all .temp assignment being covered?
> 

I have checked all .temp assignments. But for read operations, this variable
is not used to determine write hints. so it is not initialized in this case.

Thanks,

> Thanks,
> 
>>
>> Thanks,
>>
>>> Thanks,
>>>
>>>> +
>>>>  	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]);
>>>>  
>>>>  	if (rw == WRITE) {
>>>> +		if (sbi->whint_mode == WHINT_MODE_OFF)
>>>> +			iocb->ki_hint = hint;
>>>>  		if (err > 0) {
>>>>  			f2fs_update_iostat(F2FS_I_SB(inode), APP_DIRECT_IO,
>>>>  									err);
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index b7ba496..d7c2797 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -1035,6 +1035,11 @@ enum {
>>>>  	MAX_TIME,
>>>>  };
>>>>  
>>>> +enum {
>>>> +	WHINT_MODE_OFF,		/* not pass down write hints */
>>>> +	WHINT_MODE_USER,	/* try to pass down hints given by users */
>>>> +};
>>>> +
>>>>  struct f2fs_sb_info {
>>>>  	struct super_block *sb;			/* pointer to VFS super block */
>>>>  	struct proc_dir_entry *s_proc;		/* proc entry */
>>>> @@ -1218,6 +1223,8 @@ struct f2fs_sb_info {
>>>>  	char *s_qf_names[MAXQUOTAS];
>>>>  	int s_jquota_fmt;			/* Format of quota to use */
>>>>  #endif
>>>> +	/* For which write hints are passed down to block layer */
>>>> +	int whint_mode;
>>>>  };
>>>>  
>>>>  #ifdef CONFIG_F2FS_FAULT_INJECTION
>>>> @@ -2766,6 +2773,8 @@ int lookup_journal_in_cursum(struct f2fs_journal *journal, int type,
>>>>  int __init create_segment_manager_caches(void);
>>>>  void destroy_segment_manager_caches(void);
>>>>  int rw_hint_to_seg_type(enum rw_hint hint);
>>>> +enum rw_hint io_type_to_rw_hint(struct f2fs_sb_info *sbi, enum page_type type,
>>>> +				enum temp_type temp);
>>>>  
>>>>  /*
>>>>   * checkpoint.c
>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>> index e5739ce..8bc1fc1 100644
>>>> --- a/fs/f2fs/segment.c
>>>> +++ b/fs/f2fs/segment.c
>>>> @@ -2458,6 +2458,62 @@ int rw_hint_to_seg_type(enum rw_hint hint)
>>>>  	}
>>>>  }
>>>>  
>>>> +/* This returns write hints for each segment type. This hints will be
>>>> + * passed down to block layer. There are 2 mapping tables which depend on
>>>> + * the mount option 'whint'.
>>>> + *
>>>> + * 1) whint_mode=user-based. F2FS tries to pass down hints given by users.
>>>> + *
>>>> + * User                  F2FS                     Block
>>>> + * ----                  ----                     -----
>>>> + *                       META                     WRITE_LIFE_NOT_SET
>>>> + *                       HOT_NODE                 "
>>>> + *                       WARM_NODE                "
>>>> + *                       COLD_NODE                "
>>>> + * ioctl(COLD)           COLD_DATA                WRITE_LIFE_EXTREME
>>>> + * extension list        "                        "
>>>> + *
>>>> + * -- buffered io
>>>> + * WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
>>>> + * WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
>>>> + * WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_NOT_SET
>>>> + * WRITE_LIFE_NONE       "                        "
>>>> + * WRITE_LIFE_MEDIUM     "                        "
>>>> + * WRITE_LIFE_LONG       "                        "
>>>> + *
>>>> + * -- direct io
>>>> + * WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
>>>> + * WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
>>>> + * WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_NOT_SET
>>>> + * WRITE_LIFE_NONE       "                        WRITE_LIFE_NONE
>>>> + * WRITE_LIFE_MEDIUM     "                        WRITE_LIFE_MEDIUM
>>>> + * WRITE_LIFE_LONG       "                        WRITE_LIFE_LONG
>>>> + *
>>>> + * 2) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET.
>>>> + *
>>>> + */
>>>> +
>>>> +enum rw_hint io_type_to_rw_hint(struct f2fs_sb_info *sbi,
>>>> +				enum page_type type, enum temp_type temp)
>>>> +{
>>>> +	if (sbi->whint_mode == WHINT_MODE_USER) {
>>>> +		if (type == DATA) {
>>>> +			switch (temp) {
>>>> +			case COLD:
>>>> +				return WRITE_LIFE_EXTREME;
>>>> +			case HOT:
>>>> +				return WRITE_LIFE_SHORT;
>>>> +			default:
>>>> +				return WRITE_LIFE_NOT_SET;
>>>> +			}
>>>> +		} else {
>>>> +			return WRITE_LIFE_NOT_SET;
>>>> +		}
>>>> +	} else {
>>>> +		return WRITE_LIFE_NOT_SET;
>>>> +	}
>>>> +}
>>>> +
>>>>  static int __get_segment_type_2(struct f2fs_io_info *fio)
>>>>  {
>>>>  	if (fio->type == DATA)
>>>> @@ -2645,6 +2701,7 @@ void write_meta_page(struct f2fs_sb_info *sbi, struct page *page,
>>>>  	struct f2fs_io_info fio = {
>>>>  		.sbi = sbi,
>>>>  		.type = META,
>>>> +		.temp = HOT,
>>>
>>> Could you check to make sure all .temp being covered?
>>>
>>>>  		.op = REQ_OP_WRITE,
>>>>  		.op_flags = REQ_SYNC | REQ_META | REQ_PRIO,
>>>>  		.old_blkaddr = page->index,
>>>> @@ -2693,6 +2750,8 @@ int rewrite_data_page(struct f2fs_io_info *fio)
>>>>  	int err;
>>>>  
>>>>  	fio->new_blkaddr = fio->old_blkaddr;
>>>> +	/* i/o temperature is needed for passing down write hints */
>>>> +	__get_segment_type(fio);
>>>>  	stat_inc_inplace_blocks(fio->sbi);
>>>>  
>>>>  	err = f2fs_submit_page_bio(fio);
>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>> index 8173ae6..9e22926 100644
>>>> --- a/fs/f2fs/super.c
>>>> +++ b/fs/f2fs/super.c
>>>> @@ -129,6 +129,7 @@ enum {
>>>>  	Opt_jqfmt_vfsold,
>>>>  	Opt_jqfmt_vfsv0,
>>>>  	Opt_jqfmt_vfsv1,
>>>> +	Opt_whint,
>>>>  	Opt_err,
>>>>  };
>>>>  
>>>> @@ -182,6 +183,7 @@ enum {
>>>>  	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
>>>>  	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
>>>>  	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
>>>> +	{Opt_whint, "whint_mode=%s"},
>>>>  	{Opt_err, NULL},
>>>>  };
>>>>  
>>>> @@ -679,6 +681,22 @@ static int parse_options(struct super_block *sb, char *options)
>>>>  					"quota operations not supported");
>>>>  			break;
>>>>  #endif
>>>> +		case Opt_whint:
>>>> +			name = match_strdup(&args[0]);
>>>> +			if (!name)
>>>> +				return -ENOMEM;
>>>> +			if (strlen(name) == 10 &&
>>>> +					!strncmp(name, "user-based", 10)) {
>>>> +				sbi->whint_mode = WHINT_MODE_USER;
>>>> +			} else if (strlen(name) == 3 &&
>>>> +					!strncmp(name, "off", 3)) {
>>>> +				sbi->whint_mode = WHINT_MODE_OFF;
>>>> +			} else {
>>>> +				kfree(name);
>>>> +				return -EINVAL;
>>>> +			}
>>>> +			kfree(name);
>>>> +			break;
>>>>  		default:
>>>>  			f2fs_msg(sb, KERN_ERR,
>>>>  				"Unrecognized mount option \"%s\" or missing value",
>>>> @@ -1225,6 +1243,8 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
>>>>  		seq_puts(seq, ",prjquota");
>>>>  #endif
>>>>  	f2fs_show_quota_options(seq, sbi->sb);
>>>> +	if (sbi->whint_mode == WHINT_MODE_USER)
>>>> +		seq_printf(seq, ",whint_mode=%s", "user-based");
>>>>  
>>>>  	return 0;
>>>>  }
>>>> @@ -1234,6 +1254,7 @@ static void default_options(struct f2fs_sb_info *sbi)
>>>>  	/* init some FS parameters */
>>>>  	sbi->active_logs = NR_CURSEG_TYPE;
>>>>  	sbi->inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
>>>> +	sbi->whint_mode = WHINT_MODE_OFF;
>>>>  
>>>>  	set_opt(sbi, BG_GC);
>>>>  	set_opt(sbi, INLINE_XATTR);
>>>> @@ -1274,6 +1295,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
>>>>  	bool need_restart_gc = false;
>>>>  	bool need_stop_gc = false;
>>>>  	bool no_extent_cache = !test_opt(sbi, EXTENT_CACHE);
>>>> +	int old_whint_mode = sbi->whint_mode;
>>>>  #ifdef CONFIG_F2FS_FAULT_INJECTION
>>>>  	struct f2fs_fault_info ffi = sbi->fault_info;
>>>>  #endif
>>>> @@ -1373,7 +1395,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
>>>>  		need_stop_gc = true;
>>>>  	}
>>>>  
>>>> -	if (*flags & SB_RDONLY) {
>>>> +	if (*flags & SB_RDONLY || sbi->whint_mode != old_whint_mode) {
>>>>  		writeback_inodes_sb(sb, WB_REASON_SYNC);
>>>>  		sync_inodes_sb(sb);
>>>>  
>>>>
>>>
>>
>> .
>>
> 
>