Re: [PATCH] Introduce lifetime write IO statistics

[Chao Yu <chao2.yu@samsung.com>]

Hi,

> -----Original Message-----
> From: Liu Shuoran [mailto:liushuoran@huawei.com]
> Sent: Tuesday, January 26, 2016 3:41 PM
> To: jaegeuk@kernel.org
> Cc: linux-f2fs-devel@lists.sourceforge.net
> Subject: [f2fs-dev] [PATCH] Introduce lifetime write IO statistics
> 
> This patch introduces lifetime IO write statistics exposed to the sysfs interface.
> The write IO amount is obtained from block layer, accumulated in the file system and
> stored in the hot node summary of checkpoint.
> 
> Signed-off-by: Shuoran Liu <liushuoran@huawei.com>
> Signed-off-by: Pengyang Hou <houpengyang@huawei.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/checkpoint.c    | 12 ++++++++++++
>  fs/f2fs/f2fs.h          | 11 +++++++++++
>  fs/f2fs/super.c         | 35 +++++++++++++++++++++++++++++++++++
>  include/linux/f2fs_fs.h | 14 +++++++++++++-
>  4 files changed, 71 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 3842af9..998de47 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -921,6 +921,10 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>  	int cp_payload_blks = __cp_payload(sbi);
>  	block_t discard_blk = NEXT_FREE_BLKADDR(sbi, curseg);
>  	bool invalidate = false;
> +	struct super_block *sb = sbi->sb;
> +	struct curseg_info *seg_i = CURSEG_I(sbi, CURSEG_HOT_NODE);
> +	u64 kbytes_written;
> +
> 
>  	/*
>  	 * This avoids to conduct wrong roll-forward operations and uses
> @@ -1034,6 +1038,14 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control
> *cpc)
> 
>  	write_data_summaries(sbi, start_blk);
>  	start_blk += data_sum_blocks;
> +
> +	/* Record write statistics in the hot node summary */
> +	kbytes_written = sbi->kbytes_written;
> +	if (sb->s_bdev->bd_part)
> +		kbytes_written += BD_PART_WRITTEN(sbi);
> +
> +	seg_i->sum_blk->info.kbytes_written = cpu_to_le64(kbytes_written);
> +
>  	if (__remain_node_summaries(cpc->reason)) {
>  		write_node_summaries(sbi, start_blk);
>  		start_blk += NR_CURSEG_NODE_TYPE;
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index ff79054..cee5fab0 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -844,8 +844,19 @@ struct f2fs_sb_info {
>  	struct list_head s_list;
>  	struct mutex umount_mutex;
>  	unsigned int shrinker_run_no;
> +
> +	/* For write statistics */
> +	u64 sectors_written_start;
> +	u64 kbytes_written;
>  };
> 
> +/* For write statistics. Suppose sector size is 512 bytes,
> + * and the return value is in kbytes. s is of struct f2fs_sb_info.
> + */
> +#define BD_PART_WRITTEN(s)						 \
> +(((u64)part_stat_read(s->sb->s_bdev->bd_part, sectors[1]) -		 \
> +		s->sectors_written_start) >> 1)
> +
>  static inline void f2fs_update_time(struct f2fs_sb_info *sbi, int type)
>  {
>  	sbi->last_time[type] = jiffies;
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 3bf990b..7ed10f1 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -126,6 +126,19 @@ static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int
> struct_type)
>  	return NULL;
>  }
> 
> +static ssize_t lifetime_write_kbytes_show(struct f2fs_attr *a,
> +		struct f2fs_sb_info *sbi, char *buf)
> +{
> +	struct super_block *sb = sbi->sb;
> +
> +	if (!sb->s_bdev->bd_part)
> +		return snprintf(buf, PAGE_SIZE, "0\n");
> +
> +	return snprintf(buf, PAGE_SIZE, "%llu\n",
> +		(unsigned long long)(sbi->kbytes_written +
> +			BD_PART_WRITTEN(sbi)));
> +}
> +
>  static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
>  			struct f2fs_sb_info *sbi, char *buf)
>  {
> @@ -204,6 +217,9 @@ static struct f2fs_attr f2fs_attr_##_name = {			\
>  		f2fs_sbi_show, f2fs_sbi_store,			\
>  		offsetof(struct struct_name, elname))
> 
> +#define F2FS_GENERAL_RO_ATTR(name) \
> +static struct f2fs_attr f2fs_attr_##name = __ATTR(name, 0444, name##_show, NULL)
> +
>  F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_min_sleep_time, min_sleep_time);
>  F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_max_sleep_time, max_sleep_time);
>  F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
> @@ -220,6 +236,7 @@ F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, max_victim_search,
> max_victim_search);
>  F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, dir_level, dir_level);
>  F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, cp_interval, interval_time[CP_TIME]);
>  F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, idle_interval, interval_time[REQ_TIME]);
> +F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
> 
>  #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
>  static struct attribute *f2fs_attrs[] = {
> @@ -239,6 +256,7 @@ static struct attribute *f2fs_attrs[] = {
>  	ATTR_LIST(ra_nid_pages),
>  	ATTR_LIST(cp_interval),
>  	ATTR_LIST(idle_interval),
> +	ATTR_LIST(lifetime_write_kbytes),
>  	NULL,
>  };
> 
> @@ -766,6 +784,11 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
>  	bool need_stop_gc = false;
>  	bool no_extent_cache = !test_opt(sbi, EXTENT_CACHE);
> 
> +	if (*flags & MS_RDONLY) {
> +		set_opt(sbi, FASTBOOT);

Need to recover to original mode, otherwise it may change option user
set.

> +		set_sbi_flag(sbi, SBI_IS_DIRTY);
> +	}
> +
>  	sync_filesystem(sb);
> 
>  	/*
> @@ -1242,6 +1265,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>  	bool retry = true, need_fsck = false;
>  	char *options = NULL;
>  	int recovery, i, valid_super_block;
> +	struct curseg_info *seg_i;
> 
>  try_onemore:
>  	err = -EINVAL;
> @@ -1372,6 +1396,17 @@ try_onemore:
>  		goto free_nm;
>  	}
> 
> +	/* For write statistics */
> +	if (sb->s_bdev->bd_part)
> +		sbi->sectors_written_start =
> +			(u64)part_stat_read(sb->s_bdev->bd_part, sectors[1]);
> +
> +	/* Read accumulated write IO statistics if exists */
> +	seg_i = CURSEG_I(sbi, CURSEG_HOT_NODE);

Why not CURSEG_WARM_DATA?

Thanks,

> +	if(__exist_node_summaries(sbi))
> +		sbi->kbytes_written =
> +			le64_to_cpu(seg_i->sum_blk->info.kbytes_written);
> +
>  	build_gc_manager(sbi);
> 
>  	/* get an inode for node space */
> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
> index e59c3be..67aa01d 100644
> --- a/include/linux/f2fs_fs.h
> +++ b/include/linux/f2fs_fs.h
> @@ -358,6 +358,12 @@ struct summary_footer {
>  				sizeof(struct sit_journal_entry))
>  #define SIT_JOURNAL_RESERVED	((SUM_JOURNAL_SIZE - 2) %\
>  				sizeof(struct sit_journal_entry))
> +
> +/* Reserved area should make size of f2fs_extra_info equals to
> + * that of nat_journal and sit_journal.
> + */
> +#define EXTRA_INFO_RESERVED	(SUM_JOURNAL_SIZE - 2 - 8)
> +
>  /*
>   * frequently updated NAT/SIT entries can be stored in the spare area in
>   * summary blocks
> @@ -387,6 +393,11 @@ struct sit_journal {
>  	__u8 reserved[SIT_JOURNAL_RESERVED];
>  } __packed;
> 
> +struct f2fs_extra_info {
> +	__le64 kbytes_written;
> +	__u8 reserved[EXTRA_INFO_RESERVED];
> +} __packed;
> +
>  /* 4KB-sized summary block structure */
>  struct f2fs_summary_block {
>  	struct f2fs_summary entries[ENTRIES_IN_SUM];
> @@ -394,10 +405,11 @@ struct f2fs_summary_block {
>  		__le16 n_nats;
>  		__le16 n_sits;
>  	};
> -	/* spare area is used by NAT or SIT journals */
> +	/* spare area is used by NAT or SIT journals or extra info */
>  	union {
>  		struct nat_journal nat_j;
>  		struct sit_journal sit_j;
> +		struct f2fs_extra_info info;
>  	};
>  	struct summary_footer footer;
>  } __packed;
> --
> 1.9.1
> 
> 
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