From: Chao Yu <yuchao0@huawei.com>
Date: Mon, 9 Apr 2018 02:25:23 +0000 (+0800)
Subject: f2fs: don't split checkpoint in fstrim
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=377224c471188a2c9a838f919160546f4e842ab8;p=openwrt%2Fstaging%2Fblogic.git

f2fs: don't split checkpoint in fstrim

Now, we issue discard asynchronously in separated thread instead of in
checkpoint, after that, we won't encounter long latency in checkpoint
due to huge number of synchronous discard command handling, so, we don't
need to split checkpoint to do trim in batch, merge it and obsolete
related sysfs entry.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 540553c933b6..372b88f4e706 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -101,6 +101,7 @@ Date:		February 2015
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
 Description:
 		 Controls the trimming rate in batch mode.
+		 <deprecated>
 
 What:		/sys/fs/f2fs/<disk>/cp_interval
 Date:		October 2015
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 27231fe8a6b2..534872d064bc 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -176,11 +176,6 @@ enum {
 #define	CP_DISCARD	0x00000010
 #define CP_TRIMMED	0x00000020
 
-#define DEF_BATCHED_TRIM_SECTIONS	2048
-#define BATCHED_TRIM_SEGMENTS(sbi)	\
-		(GET_SEG_FROM_SEC(sbi, SM_I(sbi)->trim_sections))
-#define BATCHED_TRIM_BLOCKS(sbi)	\
-		(BATCHED_TRIM_SEGMENTS(sbi) << (sbi)->log_blocks_per_seg)
 #define MAX_DISCARD_BLOCKS(sbi)		BLKS_PER_SEC(sbi)
 #define DEF_MAX_DISCARD_REQUEST		8	/* issue 8 discards per round */
 #define DEF_MAX_DISCARD_LEN		512	/* Max. 2MB per discard */
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 8c1f7a6bf178..3db035bf7203 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2395,7 +2395,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 {
 	__u64 start = F2FS_BYTES_TO_BLK(range->start);
 	__u64 end = start + F2FS_BYTES_TO_BLK(range->len) - 1;
-	unsigned int start_segno, end_segno, cur_segno;
+	unsigned int start_segno, end_segno;
 	block_t start_block, end_block;
 	struct cp_control cpc;
 	struct discard_policy dpolicy;
@@ -2421,40 +2421,27 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 
 	cpc.reason = CP_DISCARD;
 	cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
+	cpc.trim_start = start_segno;
+	cpc.trim_end = end_segno;
 
-	/* do checkpoint to issue discard commands safely */
-	for (cur_segno = start_segno; cur_segno <= end_segno;
-					cur_segno = cpc.trim_end + 1) {
-		cpc.trim_start = cur_segno;
-
-		if (sbi->discard_blks == 0)
-			break;
-		else if (sbi->discard_blks < BATCHED_TRIM_BLOCKS(sbi))
-			cpc.trim_end = end_segno;
-		else
-			cpc.trim_end = min_t(unsigned int,
-				rounddown(cur_segno +
-				BATCHED_TRIM_SEGMENTS(sbi),
-				sbi->segs_per_sec) - 1, end_segno);
-
-		mutex_lock(&sbi->gc_mutex);
-		err = write_checkpoint(sbi, &cpc);
-		mutex_unlock(&sbi->gc_mutex);
-		if (err)
-			break;
+	if (sbi->discard_blks == 0)
+		goto out;
 
-		schedule();
-	}
+	mutex_lock(&sbi->gc_mutex);
+	err = write_checkpoint(sbi, &cpc);
+	mutex_unlock(&sbi->gc_mutex);
+	if (err)
+		goto out;
 
 	start_block = START_BLOCK(sbi, start_segno);
-	end_block = START_BLOCK(sbi, min(cur_segno, end_segno) + 1);
+	end_block = START_BLOCK(sbi, end_segno + 1);
 
 	__init_discard_policy(sbi, &dpolicy, DPOLICY_FSTRIM, cpc.trim_minlen);
 	__issue_discard_cmd_range(sbi, &dpolicy, start_block, end_block);
 	trimmed = __wait_discard_cmd_range(sbi, &dpolicy,
 					start_block, end_block);
-out:
 	range->len = F2FS_BLK_TO_BYTES(trimmed);
+out:
 	return err;
 }
 
@@ -3841,8 +3828,6 @@ int build_segment_manager(struct f2fs_sb_info *sbi)
 	sm_info->min_hot_blocks = DEF_MIN_HOT_BLOCKS;
 	sm_info->min_ssr_sections = reserved_sections(sbi);
 
-	sm_info->trim_sections = DEF_BATCHED_TRIM_SECTIONS;
-
 	INIT_LIST_HEAD(&sm_info->sit_entry_set);
 
 	init_rwsem(&sm_info->curseg_lock);
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index f33a56d6e6dd..2c53de9251be 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -245,6 +245,9 @@ out:
 		return count;
 	}
 
+	if (!strcmp(a->attr.name, "trim_sections"))
+		return -EINVAL;
+
 	*ui = t;
 
 	if (!strcmp(a->attr.name, "iostat_enable") && *ui == 0)