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Commit bba681cb authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: introduce a batched trim 



This patch introduces a batched trimming feature, which submits split discard
commands.

This is to avoid long latency due to huge trim commands.
If fstrim was triggered ranging from 0 to the end of device, we should lock
all the checkpoint-related mutexes, resulting in very long latency.

Reviewed-by: default avatarChao Yu <chao2.yu@samsung.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 487261f3

Documentation/ABI/testing/sysfs-fs-f2fs

+6 −0
Original line number Diff line number Diff line
@@ -74,3 +74,9 @@ Date: March 2014 
Contact:	"Jaegeuk Kim" <jaegeuk.kim@samsung.com>

Description:

		 Controls the memory footprint used by f2fs.



What:		/sys/fs/f2fs/<disk>/trim_sections

Date:		February 2015

Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>

Description:

		 Controls the trimming rate in batch mode.

Documentation/filesystems/f2fs.txt

+4 −0
Original line number Diff line number Diff line
@@ -199,6 +199,10 @@ Files in /sys/fs/f2fs/<devname> 
			      checkpoint is triggered, and issued during the

			      checkpoint. By default, it is disabled with 0.



 trim_sections                This parameter controls the number of sections

                              to be trimmed out in batch mode when FITRIM

                              conducts. 32 sections is set by default.



 ipu_policy                   This parameter controls the policy of in-place

                              updates in f2fs. There are five policies:

                               0x01: F2FS_IPU_FORCE, 0x02: F2FS_IPU_SSR,

fs/f2fs/f2fs.h

+7 −0
Original line number Diff line number Diff line
@@ -105,6 +105,10 @@ enum { 
	CP_DISCARD,

};



#define DEF_BATCHED_TRIM_SECTIONS	32

#define BATCHED_TRIM_SEGMENTS(sbi)	\

		(SM_I(sbi)->trim_sections * (sbi)->segs_per_sec)



struct cp_control {

	int reason;

	__u64 trim_start;
@@ -448,6 +452,9 @@ struct f2fs_sm_info { 
	int nr_discards;			/* # of discards in the list */

	int max_discards;			/* max. discards to be issued */



	/* for batched trimming */

	unsigned int trim_sections;		/* # of sections to trim */



	struct list_head sit_entry_set;	/* sit entry set list */



	unsigned int ipu_policy;	/* in-place-update policy */

fs/f2fs/segment.c

+12 −5
Original line number Diff line number Diff line
@@ -1066,14 +1066,19 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range) 
	end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :

						GET_SEGNO(sbi, end);

	cpc.reason = CP_DISCARD;

	cpc.trim_start = start_segno;

	cpc.trim_end = end_segno;

	cpc.trim_minlen = range->minlen >> sbi->log_blocksize;



	/* do checkpoint to issue discard commands safely */

	for (; start_segno <= end_segno; start_segno = cpc.trim_end + 1) {

		cpc.trim_start = start_segno;

		cpc.trim_end = min_t(unsigned int, rounddown(start_segno +

				BATCHED_TRIM_SEGMENTS(sbi),

				sbi->segs_per_sec) - 1, end_segno);



		mutex_lock(&sbi->gc_mutex);

		write_checkpoint(sbi, &cpc);

		mutex_unlock(&sbi->gc_mutex);

	}

out:

	range->len = cpc.trimmed << sbi->log_blocksize;

	return 0;
@@ -2127,6 +2132,8 @@ int build_segment_manager(struct f2fs_sb_info *sbi) 
	sm_info->nr_discards = 0;

	sm_info->max_discards = 0;



	sm_info->trim_sections = DEF_BATCHED_TRIM_SECTIONS;



	INIT_LIST_HEAD(&sm_info->sit_entry_set);



	if (test_opt(sbi, FLUSH_MERGE) && !f2fs_readonly(sbi->sb)) {

fs/f2fs/super.c

+2 −0
Original line number Diff line number Diff line
@@ -195,6 +195,7 @@ F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time); 
F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_idle, gc_idle);

F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments);

F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, max_small_discards, max_discards);

F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections);

F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy);

F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util);

F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_fsync_blocks, min_fsync_blocks);
@@ -210,6 +211,7 @@ static struct attribute *f2fs_attrs[] = { 
	ATTR_LIST(gc_idle),

	ATTR_LIST(reclaim_segments),

	ATTR_LIST(max_small_discards),

	ATTR_LIST(batched_trim_sections),

	ATTR_LIST(ipu_policy),

	ATTR_LIST(min_ipu_util),

	ATTR_LIST(min_fsync_blocks),