Re: [f2fs-dev] [PATCH v2] f2fs: add new idle interval timing for discard and gc paths

From: Jaegeuk Kim
Date: Tue Sep 11 2018 - 18:10:02 EST

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In reply to: Chao Yu: "Re: [f2fs-dev] [PATCH v2] f2fs: add new idle interval timing for discard and gc paths"
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On 09/11, Chao Yu wrote:
> On 2018/9/10 11:47, Sahitya Tummala wrote:
> > This helps to control the frequency of submission of discard and
> > GC requests independently, based on the need. The sleep timing of
> > GC thread is now aligned with this idle time when the dev is busy,
> > to avoid unnecessary periodic wakeups.
> >
> > Suggested-by: Chao Yu <yuchao0@xxxxxxxxxx>
> > Signed-off-by: Sahitya Tummala <stummala@xxxxxxxxxxxxxx>
> > ---
> > v2:
> > -fix __issue_discard_cmd_orderly() path
> >
> > Documentation/ABI/testing/sysfs-fs-f2fs | 17 ++++++++++++++++-
> > fs/f2fs/f2fs.h | 31 +++++++++++++++++++++++++++----
> > fs/f2fs/gc.c | 6 ++++--
> > fs/f2fs/segment.c | 16 ++++++----------
> > fs/f2fs/super.c | 2 ++
> > fs/f2fs/sysfs.c | 5 +++++
> > 6 files changed, 60 insertions(+), 17 deletions(-)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> > index 94a24ae..3ac4177 100644
> > --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> > +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> > @@ -121,7 +121,22 @@ What: /sys/fs/f2fs/<disk>/idle_interval
> > Date: January 2016
> > Contact: "Jaegeuk Kim" <jaegeuk@xxxxxxxxxx>
> > Description:
> > - Controls the idle timing.
> > + Controls the idle timing for all paths other than
> > + discard and gc path.
> > +
> > +What: /sys/fs/f2fs/<disk>/discard_idle_interval
> > +Date: September 2018
> > +Contact: "Chao Yu" <yuchao0@xxxxxxxxxx>
> > +Contact: "Sahitya Tummala" <stummala@xxxxxxxxxxxxxx>
> > +Description:
> > + Controls the idle timing for discard path.
> > +
> > +What: /sys/fs/f2fs/<disk>/gc_idle_interval
> > +Date: September 2018
> > +Contact: "Chao Yu" <yuchao0@xxxxxxxxxx>
> > +Contact: "Sahitya Tummala" <stummala@xxxxxxxxxxxxxx>
> > +Description:
> > + Controls the idle timing for gc path.
> >
> > What: /sys/fs/f2fs/<disk>/iostat_enable
> > Date: August 2017
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index abf9256..6070681 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1093,6 +1093,8 @@ enum {
> > enum {
> > CP_TIME,
> > REQ_TIME,
> > + DISCARD_TIME,
> > + GC_TIME,
> > MAX_TIME,
> > };
> >
> > @@ -1347,14 +1349,35 @@ static inline void f2fs_update_time(struct f2fs_sb_info *sbi, int type)
> > sbi->last_time[type] = jiffies;
> > }
> >
> > -static inline bool f2fs_time_over(struct f2fs_sb_info *sbi, int type)
> > +static inline bool f2fs_time_over_cp(struct f2fs_sb_info *sbi)

I don't see why we need this separately.

> > +{
> > + unsigned long interval = sbi->interval_time[CP_TIME] * HZ;
> > +
> > + return time_after(jiffies, sbi->last_time[CP_TIME] + interval);
> > +}
> > +
> > +static inline bool f2fs_time_over_req(struct f2fs_sb_info *sbi, int type)
> > +{
> > + unsigned long interval = sbi->interval_time[type] * HZ;
> > +
> > + return time_after(jiffies, sbi->last_time[REQ_TIME] + interval);
> > +}
> > +
> > +static inline unsigned int f2fs_get_wait_time(struct f2fs_sb_info *sbi,
> > + int type)

f2fs_time_to_wait()?

> > {
> > unsigned long interval = sbi->interval_time[type] * HZ;
> > + unsigned int wait_ms = 0;
> > + long delta;
> > +
> > + delta = (sbi->last_time[REQ_TIME] + interval) - jiffies;
> > + if (delta > 0)
> > + wait_ms = jiffies_to_msecs(delta);
> >
> > - return time_after(jiffies, sbi->last_time[type] + interval);
> > + return wait_ms;
> > }
> >
> > -static inline bool is_idle(struct f2fs_sb_info *sbi)
> > +static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
> > {
> > struct block_device *bdev = sbi->sb->s_bdev;
> > struct request_queue *q = bdev_get_queue(bdev);
> > @@ -1363,7 +1386,7 @@ static inline bool is_idle(struct f2fs_sb_info *sbi)
> > if (rl->count[BLK_RW_SYNC] || rl->count[BLK_RW_ASYNC])
> > return false;
> >
> > - return f2fs_time_over(sbi, REQ_TIME);
> > + return f2fs_time_over_req(sbi, type);
> > }
> >
> > /*
> > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > index 5c8d004..c0bafea 100644
> > --- a/fs/f2fs/gc.c
> > +++ b/fs/f2fs/gc.c
> > @@ -83,8 +83,10 @@ static int gc_thread_func(void *data)
> > if (!mutex_trylock(&sbi->gc_mutex))
> > goto next;
> >
> > - if (!is_idle(sbi)) {
> > - increase_sleep_time(gc_th, &wait_ms);
> > + if (!is_idle(sbi, GC_TIME)) {
> > + wait_ms = f2fs_get_wait_time(sbi, GC_TIME);
>
> It seems this patch changes the method of increasing wait_ms here, if device is
> busy, we may wake up GC thread earlier than before, not sure we should do this.
>
> To Jaegeuk, how do you think of this?

Yes, please let us discuss this in another patch.

>
> Thanks,
>
> > + if (!wait_ms)
> > + increase_sleep_time(gc_th, &wait_ms);
> > mutex_unlock(&sbi->gc_mutex);
> > goto next;
> > }
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index c5024f8..2d15733 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -511,7 +511,7 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
> > else
> > f2fs_build_free_nids(sbi, false, false);
> >
> > - if (!is_idle(sbi) &&
> > + if (!is_idle(sbi, REQ_TIME) &&
> > (!excess_dirty_nats(sbi) && !excess_dirty_nodes(sbi)))
> > return;
> >
> > @@ -521,7 +521,7 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
> > excess_prefree_segs(sbi) ||
> > excess_dirty_nats(sbi) ||
> > excess_dirty_nodes(sbi) ||
> > - f2fs_time_over(sbi, CP_TIME)) {
> > + f2fs_time_over_cp(sbi)) {
> > if (test_opt(sbi, DATA_FLUSH)) {
> > struct blk_plug plug;
> >
> > @@ -1311,7 +1311,7 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
> > if (dc->state != D_PREP)
> > goto next;
> >
> > - if (dpolicy->io_aware && !is_idle(sbi)) {
> > + if (dpolicy->io_aware && !is_idle(sbi, DISCARD_TIME)) {
> > io_interrupted = true;
> > break;
> > }
> > @@ -1371,7 +1371,7 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> > f2fs_bug_on(sbi, dc->state != D_PREP);
> >
> > if (dpolicy->io_aware && i < dpolicy->io_aware_gran &&
> > - !is_idle(sbi)) {
> > + !is_idle(sbi, DISCARD_TIME)) {
> > io_interrupted = true;
> > break;
> > }
> > @@ -1564,8 +1564,6 @@ static int issue_discard_thread(void *data)
> > struct discard_policy dpolicy;
> > unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
> > int issued;
> > - unsigned long interval = sbi->interval_time[REQ_TIME] * HZ;
> > - long delta;
> >
> > set_freezable();
> >
> > @@ -1602,10 +1600,8 @@ static int issue_discard_thread(void *data)
> > __wait_all_discard_cmd(sbi, &dpolicy);
> > wait_ms = dpolicy.min_interval;
> > } else if (issued == -1){
> > - delta = (sbi->last_time[REQ_TIME] + interval) - jiffies;
> > - if (delta > 0)
> > - wait_ms = jiffies_to_msecs(delta);
> > - else
> > + wait_ms = f2fs_get_wait_time(sbi, DISCARD_TIME);
> > + if (!wait_ms)
> > wait_ms = dpolicy.mid_interval;
> > } else {
> > wait_ms = dpolicy.max_interval;
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 896b885..1706f45 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -2423,6 +2423,8 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
> > sbi->dir_level = DEF_DIR_LEVEL;
> > sbi->interval_time[CP_TIME] = DEF_CP_INTERVAL;
> > sbi->interval_time[REQ_TIME] = DEF_IDLE_INTERVAL;
> > + sbi->interval_time[DISCARD_TIME] = DEF_IDLE_INTERVAL;
> > + sbi->interval_time[GC_TIME] = DEF_IDLE_INTERVAL;
> > clear_sbi_flag(sbi, SBI_NEED_FSCK);
> >
> > for (i = 0; i < NR_COUNT_TYPE; i++)
> > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> > index 81c0e53..0afe99c 100644
> > --- a/fs/f2fs/sysfs.c
> > +++ b/fs/f2fs/sysfs.c
> > @@ -407,6 +407,9 @@ static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> > 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_RW_ATTR(F2FS_SBI, f2fs_sb_info, discard_idle_interval,
> > + interval_time[DISCARD_TIME]);
> > +F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_idle_interval, interval_time[GC_TIME]);
> > F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, iostat_enable, iostat_enable);
> > F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, readdir_ra, readdir_ra);
> > F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_pin_file_thresh, gc_pin_file_threshold);
> > @@ -460,6 +463,8 @@ static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> > ATTR_LIST(dirty_nats_ratio),
> > ATTR_LIST(cp_interval),
> > ATTR_LIST(idle_interval),
> > + ATTR_LIST(discard_idle_interval),
> > + ATTR_LIST(gc_idle_interval),
> > ATTR_LIST(iostat_enable),
> > ATTR_LIST(readdir_ra),
> > ATTR_LIST(gc_pin_file_thresh),
> >

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Previous message: Dave Chinner: "Re: [PATCH v3 3/4] fs/dcache: Track & report number of negative dentries"
In reply to: Chao Yu: "Re: [f2fs-dev] [PATCH v2] f2fs: add new idle interval timing for discard and gc paths"
Next in thread: Sahitya Tummala: "Re: [f2fs-dev] [PATCH v2] f2fs: add new idle interval timing for discard and gc paths"
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