Hi Chao,
On Wed, Jan 27, 2016 at 06:02:37PM +0800, Chao Yu wrote:
> > -----Original Message-----
> > From: Shuoran [mailto:[email protected]]
> > Sent: Wednesday, January 27, 2016 3:40 PM
> > To: Chao Yu
> > Cc: [email protected]; [email protected]
> > Subject: Re: [f2fs-dev] [PATCH] Introduce lifetime write IO statistics
> >
> > On 2016/1/27 15:20, Chao Yu wrote:
> > >> -----Original Message-----
> > >> From: Shuoran [mailto:[email protected]]
> > >> Sent: Tuesday, January 26, 2016 6:12 PM
> > >> To: Chao Yu
> > >> Cc: [email protected]; [email protected]
> > >> Subject: Re: [f2fs-dev] [PATCH] Introduce lifetime write IO statistics
> > >>
> > >> On 2016/1/26 17:24, Chao Yu wrote:
> > >>> Hi,
> > >>>
> > >>>> -----Original Message-----
> > >>>> From: Liu Shuoran [mailto:[email protected]]
> > >>>> Sent: Tuesday, January 26, 2016 3:41 PM
> > >>>> To: [email protected]
> > >>>> Cc: [email protected]
> > >>>> 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 <[email protected]>
> > >>>> Signed-off-by: Pengyang Hou <[email protected]>
> > >>>> Signed-off-by: Jaegeuk Kim <[email protected]>
> > >>>> ---
> > >>>> 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.
> > >> Yes, maybe I can bring forward the action of saving old mount options.
> > >>>> + 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?
> > >> Data summary might be compacted. So only hot/warm/cold node summary is
> > >> available, and we just picked hot node summary.
> > > Oh, you're right, warm data journal would not be persisted if data
> > > summaries are compacted, my mistake.
> > >
> > > Wouldn't be better to persist this stat number into super block like
> > > ext4?
> > >
> > > Thanks,
> >
> > I think super block in F2FS is not updated as frequent as that in Ext4
> > (there are several places invoking ext4_commit_super, while few invoking
> > f2fs_commit_super), although in this design the statistics is not
> > updated very frequently either. Another concern is that, to some extent,
> > the super blocks of f2fs is not supposed to update except for a few
> > cases. So the stat is better stored in the checkpoint, and we just tried
> > very hard finding a spare place.
>
> Got it, so the key point is preventing generating additional IO.
>
> If update points of stat in your approach is enough, so for
> 1) umount case: commit sb approach causes two more blocks updating.
> 2) remount case: commit sb approach causes one less blocks updating when
> FASTBOOT is disabled.
>
> Not a big degression. :)
>
> IMO, maybe it's better to use journal log in data segments to store
> checkpoint related data, maybe more nats/sits entries.
>
> And another thing is I'm in doubt that whether it is enough to use cp +
> data journal to update stat, since abnormal pow-cut after a normal cp would
> make us losing all stats saved before.
Pros and Cons.
IMO, we don't need to guarantee up-to-date information to users. If users wants
to keep that in high accuracy, they simply can set fastboot.
Thanks,
>
> Thanks,
>
> >
> > >>> 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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> > >>>> _______________________________________________
> > >>>> Linux-f2fs-devel mailing list
> > >>>> [email protected]
> > >>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> > >>> .
> > >>>
> > >
> > >
> > > .
> > >
> >
>
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