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

[Chao Yu]

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.

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

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);
>>>  
>>>
>>
> 
> .
>