Re: [f2fs-dev] [PATCH] f2fs: add GC_URGENT_LOW mode in gc_urgent

From: Daeho Jeong
Date: Wed Jul 01 2020 - 00:13:38 EST

Yes, it's correct.

2020ë 7ì 1ì (ì) ìí 12:35, Chao Yu <yuchao0@xxxxxxxxxx>ëì ìì:
>
> On 2020/6/30 8:54, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@xxxxxxxxxx>
> >
> > Added a new gc_urgent mode, GC_URGENT_LOW, in which mode
> > F2FS will lower the bar of checking idle in order to
> > process outstanding discard commands and GC a little bit
> > aggressively.
> >
> > Signed-off-by: Daeho Jeong <daehojeong@xxxxxxxxxx>
> > ---
> > Documentation/ABI/testing/sysfs-fs-f2fs | 4 +++-
> > fs/f2fs/f2fs.h | 10 ++++++++--
> > fs/f2fs/gc.c | 6 +++---
> > fs/f2fs/segment.c | 4 ++--
> > fs/f2fs/sysfs.c | 6 ++++--
> > 5 files changed, 20 insertions(+), 10 deletions(-)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> > index 4bb93a06d8ab..7f730c4c8df2 100644
> > --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> > +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> > @@ -229,7 +229,9 @@ Date: August 2017
> > Contact: "Jaegeuk Kim" <jaegeuk@xxxxxxxxxx>
> > Description: Do background GC agressively when set. When gc_urgent = 1,
> > background thread starts to do GC by given gc_urgent_sleep_time
> > - interval. It is set to 0 by default.
> > + interval. When gc_urgent = 2, F2FS will lower the bar of
> > + checking idle in order to process outstanding discard commands
> > + and GC a little bit aggressively. It is set to 0 by default.
> >
> > What: /sys/fs/f2fs/<disk>/gc_urgent_sleep_time
> > Date: August 2017
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index e6e47618a357..4b28fd42fdbc 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1283,7 +1283,8 @@ enum {
> > GC_NORMAL,
> > GC_IDLE_CB,
> > GC_IDLE_GREEDY,
> > - GC_URGENT,
> > + GC_URGENT_HIGH,
> > + GC_URGENT_LOW,
> > };
> >
> > enum {
> > @@ -1540,6 +1541,7 @@ struct f2fs_sb_info {
> > unsigned int cur_victim_sec; /* current victim section num */
> > unsigned int gc_mode; /* current GC state */
> > unsigned int next_victim_seg[2]; /* next segment in victim section */
> > +
> > /* for skip statistic */
> > unsigned int atomic_files; /* # of opened atomic file */
> > unsigned long long skipped_atomic_files[2]; /* FG_GC and BG_GC */
> > @@ -2480,7 +2482,7 @@ static inline void *f2fs_kmem_cache_alloc(struct kmem_cache *cachep,
> >
> > static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
> > {
> > - if (sbi->gc_mode == GC_URGENT)
> > + if (sbi->gc_mode == GC_URGENT_HIGH)
> > return true;
> >
> > if (get_pages(sbi, F2FS_RD_DATA) || get_pages(sbi, F2FS_RD_NODE) ||
> > @@ -2498,6 +2500,10 @@ static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
> > atomic_read(&SM_I(sbi)->fcc_info->queued_flush))
> > return false;
> >
> > + if (sbi->gc_mode == GC_URGENT_LOW &&
> > + (type == DISCARD_TIME || type == GC_TIME))
> > + return true;
> > +
> > return f2fs_time_over(sbi, type);
> > }
> >
> > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > index 6eec3b2d606d..3b718da69910 100644
> > --- a/fs/f2fs/gc.c
> > +++ b/fs/f2fs/gc.c
> > @@ -82,7 +82,7 @@ static int gc_thread_func(void *data)
> > * invalidated soon after by user update or deletion.
> > * So, I'd like to wait some time to collect dirty segments.
> > */
> > - if (sbi->gc_mode == GC_URGENT) {
> > + if (sbi->gc_mode == GC_URGENT_HIGH) {
> > wait_ms = gc_th->urgent_sleep_time;
> > down_write(&sbi->gc_lock);
> > goto do_gc;
> > @@ -176,7 +176,7 @@ static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
> > gc_mode = GC_CB;
> > break;
> > case GC_IDLE_GREEDY:
> > - case GC_URGENT:
> > + case GC_URGENT_HIGH:
> > gc_mode = GC_GREEDY;
> > break;
> > }
> > @@ -211,7 +211,7 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
> > * foreground GC and urgent GC cases.
> > */
> > if (gc_type != FG_GC &&
> > - (sbi->gc_mode != GC_URGENT) &&
> > + (sbi->gc_mode != GC_URGENT_HIGH) &&
> > p->max_search > sbi->max_victim_search)
> > p->max_search = sbi->max_victim_search;
> >
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index b45e473508a9..5924b3965ae4 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -174,7 +174,7 @@ bool f2fs_need_SSR(struct f2fs_sb_info *sbi)
> >
> > if (f2fs_lfs_mode(sbi))
> > return false;
> > - if (sbi->gc_mode == GC_URGENT)
> > + if (sbi->gc_mode == GC_URGENT_HIGH)
> > return true;
> > if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
> > return true;
> > @@ -1759,7 +1759,7 @@ static int issue_discard_thread(void *data)
> > continue;
> > }
> >
> > - if (sbi->gc_mode == GC_URGENT)
> > + if (sbi->gc_mode == GC_URGENT_HIGH)
> > __init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);
> >
> > sb_start_intwrite(sbi->sb);
> > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> > index e877c59b9fdb..ab40e1f89f23 100644
> > --- a/fs/f2fs/sysfs.c
> > +++ b/fs/f2fs/sysfs.c
> > @@ -350,14 +350,16 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
> > return -EINVAL;
> >
> > if (!strcmp(a->attr.name, "gc_urgent")) {
> > - if (t >= 1) {
> > - sbi->gc_mode = GC_URGENT;
> > + if (t == 1) {
> > + sbi->gc_mode = GC_URGENT_HIGH;
> > if (sbi->gc_thread) {
> > sbi->gc_thread->gc_wake = 1;
> > wake_up_interruptible_all(
> > &sbi->gc_thread->gc_wait_queue_head);
> > wake_up_discard_thread(sbi, true);
> > }
> > + } else if (t == 2) {
> > + sbi->gc_mode = GC_URGENT_LOW;
> > } else {
> > sbi->gc_mode = GC_NORMAL;
>
> As functionality description in sysfs doc, shouldn't it be:
>
> if (t == 0) {
> sbi->gc_mode = GC_NORMAL;
> } else if (t == 1) {
> sbi->gc_mode = GC_URGENT_HIGH;
> ...
> } else if (t == 2) {
> sbi->gc_mode = GC_URGENT_LOW;
> } else {
> return -EINVAL;
> }
> return count;
>
> > }
> >