Re: [f2fs-dev] [PATCH 1/2] f2fs: run discard jobs when put_super

[Jaegeuk Kim]

On 01/23, Chao Yu wrote:
> On 2019/1/23 8:02, Jaegeuk Kim wrote:
> > When we umount f2fs, we need to avoid long delay due to discard commands, which
> > is actually taking tens of seconds, if storage is very slow on UNMAP. So, this
> > patch introduces timeout-based work on it.
> > 
> > By default, let me give 5 seconds for discard.
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> > ---
> >  Documentation/ABI/testing/sysfs-fs-f2fs |  7 +++++++
> >  fs/f2fs/f2fs.h                          |  5 ++++-
> >  fs/f2fs/segment.c                       | 11 ++++++++++-
> >  fs/f2fs/super.c                         | 17 ++++++++---------
> >  fs/f2fs/sysfs.c                         |  3 +++
> >  5 files changed, 32 insertions(+), 11 deletions(-)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> > index a7ce33199457..91822ce25831 100644
> > --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> > +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> > @@ -86,6 +86,13 @@ Description:
> >  		The unit size is one block, now only support configuring in range
> >  		of [1, 512].
> >  
> > +What:          /sys/fs/f2fs/<disk>/umount_discard_timeout
> > +Date:          January 2019
> > +Contact:       "Jaegeuk Kim" <jaegeuk@xxxxxxxxxx>
> > +Description:
> > +		Set timeout to issue discard commands during umount.
> > +		Default: 5 secs
> > +
> >  What:		/sys/fs/f2fs/<disk>/max_victim_search
> >  Date:		January 2014
> >  Contact:	"Jaegeuk Kim" <jaegeuk.kim@xxxxxxxxxxx>
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 0f564883e078..6b6ec5600089 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -191,6 +191,7 @@ enum {
> >  #define DEF_CP_INTERVAL			60	/* 60 secs */
> >  #define DEF_IDLE_INTERVAL		5	/* 5 secs */
> >  #define DEF_DISABLE_INTERVAL		5	/* 5 secs */
> > +#define DEF_UMOUNT_DISCARD_TIMEOUT	5	/* 5 secs */
> >  
> >  struct cp_control {
> >  	int reason;
> > @@ -310,6 +311,7 @@ struct discard_policy {
> >  	bool sync;			/* submit discard with REQ_SYNC flag */
> >  	bool ordered;			/* issue discard by lba order */
> >  	unsigned int granularity;	/* discard granularity */
> > +	int timeout;			/* discard timeout for put_super */
> >  };
> >  
> >  struct discard_cmd_control {
> > @@ -1110,6 +1112,7 @@ enum {
> >  	DISCARD_TIME,
> >  	GC_TIME,
> >  	DISABLE_TIME,
> > +	UMOUNT_DISCARD_TIMEOUT,
> >  	MAX_TIME,
> 
> After the patch, MAX_TIME will be 6, so if we set @timeout to 6 via sysfs,
> the configuration will not be enabled due to below condition, right?

Yup.

> 
> +	if (dpolicy->timeout != MAX_TIME)
> +		f2fs_update_time(sbi, dpolicy->timeout);
> 
> >  };
> >  
> > @@ -3006,7 +3009,7 @@ void f2fs_invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr);
> >  bool f2fs_is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr);
> >  void f2fs_drop_discard_cmd(struct f2fs_sb_info *sbi);
> >  void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi);
> > -bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
> > +bool f2fs_issue_discard_timeout(struct f2fs_sb_info *sbi);
> >  void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
> >  					struct cp_control *cpc);
> >  void f2fs_dirty_to_prefree(struct f2fs_sb_info *sbi);
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 9b79056d705d..97e0faf09ebf 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -1037,6 +1037,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
> >  
> >  	dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
> >  	dpolicy->io_aware_gran = MAX_PLIST_NUM;
> > +	dpolicy->timeout = MAX_TIME;
> >  
> >  	if (discard_type == DPOLICY_BG) {
> >  		dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
> > @@ -1424,7 +1425,14 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> >  	int i, issued = 0;
> >  	bool io_interrupted = false;
> >  
> > +	if (dpolicy->timeout != MAX_TIME)
> > +		f2fs_update_time(sbi, dpolicy->timeout);
> > +
> >  	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > +		if (dpolicy->timeout != MAX_TIME &&
> > +				f2fs_time_over(sbi, dpolicy->timeout))
> > +			break;
> > +
> >  		if (i + 1 < dpolicy->granularity)
> >  			break;
> >  
> > @@ -1611,7 +1619,7 @@ void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi)
> >  }
> >  
> >  /* This comes from f2fs_put_super */
> > -bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
> > +bool f2fs_issue_discard_timeout(struct f2fs_sb_info *sbi)
> >  {
> >  	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> >  	struct discard_policy dpolicy;
> > @@ -1619,6 +1627,7 @@ bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
> >  
> >  	__init_discard_policy(sbi, &dpolicy, DPOLICY_UMOUNT,
> >  					dcc->discard_granularity);
> > +	dpolicy.timeout = UMOUNT_DISCARD_TIMEOUT;
> >  	__issue_discard_cmd(sbi, &dpolicy);
> >  	dropped = __drop_discard_cmd(sbi);
> >  
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index ea514acede36..7998ff5418f2 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -1029,6 +1029,9 @@ static void f2fs_put_super(struct super_block *sb)
> >  	int i;
> >  	bool dropped;
> >  
> > +	/* be sure to wait for any on-going discard commands */
> > +	dropped = f2fs_issue_discard_timeout(sbi);
> > +
> >  	f2fs_quota_off_umount(sb);
> >  
> >  	/* prevent remaining shrinker jobs */
> > @@ -1044,17 +1047,12 @@ static void f2fs_put_super(struct super_block *sb)
> >  		struct cp_control cpc = {
> >  			.reason = CP_UMOUNT,
> >  		};
> > -		f2fs_write_checkpoint(sbi, &cpc);
> > -	}
> >  
> > -	/* be sure to wait for any on-going discard commands */
> > -	dropped = f2fs_wait_discard_bios(sbi);
> > +		if ((f2fs_hw_support_discard(sbi) ||
> > +				f2fs_hw_should_discard(sbi)) &&
> > +				!sbi->discard_blks && !dropped)
> > +			cpc.reason |= CP_TRIMMED;
> >  
> > -	if ((f2fs_hw_support_discard(sbi) || f2fs_hw_should_discard(sbi)) &&
> > -					!sbi->discard_blks && !dropped) {
> > -		struct cp_control cpc = {
> > -			.reason = CP_UMOUNT | CP_TRIMMED,
> > -		};
> >  		f2fs_write_checkpoint(sbi, &cpc);
> 
> Still, there will be problematic as I commented in last patch, could you
> check that?
> 
> Thanks,
> 
> >  	}
> >  
> > @@ -2706,6 +2704,7 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
> >  	sbi->interval_time[DISCARD_TIME] = DEF_IDLE_INTERVAL;
> >  	sbi->interval_time[GC_TIME] = DEF_IDLE_INTERVAL;
> >  	sbi->interval_time[DISABLE_TIME] = DEF_DISABLE_INTERVAL;
> > +	sbi->interval_time[UMOUNT_DISCARD_TIMEOUT] = DEF_UMOUNT_DISCARD_TIMEOUT;
> >  	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 5b83e1d66cb3..18c627e8fc90 100644
> > --- a/fs/f2fs/sysfs.c
> > +++ b/fs/f2fs/sysfs.c
> > @@ -426,6 +426,8 @@ 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,
> > +		umount_discard_timeout, interval_time[UMOUNT_DISCARD_TIMEOUT]);
> >  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);
> > @@ -483,6 +485,7 @@ static struct attribute *f2fs_attrs[] = {
> >  	ATTR_LIST(idle_interval),
> >  	ATTR_LIST(discard_idle_interval),
> >  	ATTR_LIST(gc_idle_interval),
> > +	ATTR_LIST(umount_discard_timeout),
> >  	ATTR_LIST(iostat_enable),
> >  	ATTR_LIST(readdir_ra),
> >  	ATTR_LIST(gc_pin_file_thresh),
> >