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Message-ID: <5A6E7D93.6090402@gmail.com>
Date:   Mon, 29 Jan 2018 10:49:07 +0900
From:   Hyunchul Lee <hyc.lee@gmail.com>
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To:     Chao Yu <yuchao0@huawei.com>, Chao Yu <chao@kernel.org>,
        Jaegeuk Kim <jaegeuk@kernel.org>
CC:     linux-fsdevel@vger.kernel.org, kernel-team@lge.com,
        Hyunchul Lee <cheol.lee@lge.com>, linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH 1/3] f2fs: support passing down write hints
 given by users to block layer
References: <1516618149-1495-1-git-send-email-hyc.lee@gmail.com> <1516618149-1495-2-git-send-email-hyc.lee@gmail.com> <f7873ebb-adf5-f8c5-ede2-4427c83285aa@kernel.org> <5A694538.9080007@gmail.com> <2a4c1cb0-f692-b752-988b-5fcc17a32013@huawei.com> <5A6A6C47.1060304@gmail.com> <2707f6af-8add-5d75-ea21-c1a689011fb6@huawei.com>
In-Reply-To: <2707f6af-8add-5d75-ea21-c1a689011fb6@huawei.com>
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On 01/26/2018 11:10 AM, Chao Yu wrote:
> On 2018/1/26 7:46, Hyunchul Lee wrote:
>> 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@lge.com>
>>>>>>
>>>>>> 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@lge.com>
>>>>>> ---
>>>>>>  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
> 
> I've checked that too, there is nothing was missing.
> 
> One more thing, our whint_mode is completely based on active six type logs,
> once some of them is close due to user configuration, write IO hint will be
> messed up, so what about just enabling WHINT_MODE_OFF mode if active log
> number is two or four?
> 

Yes, I tought this is reasonable. write hints are not useful in two or four.

> And we need to adjust rw_hint_to_seg_type to be aware of active log number?
> 

We does not have any choices in the two, But we can adjust the function 
like the following in the four.

* in 4 active logs
                               F2FS
---------------------------------------
directory                      HOT_DATA
WRITE_LIFE_SHORT               HOT_DATA
others                         COLD_DATA

>> is not used to determine write hints. so it is not initialized in this case.
> 
> I think that's OK.
> 
> Thanks,
> 
>>
>> 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);
>>>>>>  
>>>>>>
>>>>>
>>>>
>>>> .
>>>>
>>>
>>>
>>
>> .
>>
> 
>