f2fs: avoid unnecessary bio submit when wait page writeback

This patch introduce is_merged_page() to check whether current page is merged in f2fs bio cache. When page is not in cache, we can avoid submitting bio cache, resulting in having more chance to merge pages. Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: avoid unnecessary bio submit when wait page writeback
This patch introduce is_merged_page() to check whether current page is merged in f2fs bio cache. When page is not in cache, we can avoid submitting bio cache, resulting in having more chance to merge pages. Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Chao Yu · Jaegeuk Kim
1 parent 3bb5e2c8fe
Showing 4 changed files with 34 additions and 8 deletions Side-by-side Diff
fs/f2fs/data.c
fs/f2fs/f2fs.h
fs/f2fs/segment.c
fs/f2fs/super.c
@@ -134,7 +134,7 @@
  
 	io = is_read_io(rw) ? &sbi->read_io : &sbi->write_io[btype];
  
-	mutex_lock(&io->io_mutex);
+	down_write(&io->io_rwsem);
  
 	/* change META to META_FLUSH in the checkpoint procedure */
 	if (type >= META_FLUSH) {
@@ -142,7 +142,7 @@
 		io->fio.rw = WRITE_FLUSH_FUA | REQ_META | REQ_PRIO;
 	}
 	__submit_merged_bio(io);
-	mutex_unlock(&io->io_mutex);
+	up_write(&io->io_rwsem);
 }
  
 /*
@@ -180,7 +180,7 @@
  
 	verify_block_addr(sbi, blk_addr);
  
-	mutex_lock(&io->io_mutex);
+	down_write(&io->io_rwsem);
  
 	if (!is_read)
 		inc_page_count(sbi, F2FS_WRITEBACK);
@@ -204,7 +204,7 @@
  
 	io->last_block_in_bio = blk_addr;
  
-	mutex_unlock(&io->io_mutex);
+	up_write(&io->io_rwsem);
 	trace_f2fs_submit_page_mbio(page, fio->rw, fio->type, blk_addr);
 }
  
@@ -394,7 +394,7 @@
 	struct bio *bio;		/* bios to merge */
 	sector_t last_block_in_bio;	/* last block number */
 	struct f2fs_io_info fio;	/* store buffered io info. */
-	struct mutex io_mutex;		/* mutex for bio */
+	struct rw_semaphore io_rwsem;	/* blocking op for bio */
 };
  
 struct f2fs_sb_info {
@@ -1046,12 +1046,38 @@
 	mutex_unlock(&curseg->curseg_mutex);
 }
  
+static inline bool is_merged_page(struct f2fs_sb_info *sbi,
+					struct page *page, enum page_type type)
+{
+	enum page_type btype = PAGE_TYPE_OF_BIO(type);
+	struct f2fs_bio_info *io = &sbi->write_io[btype];
+	struct bio *bio = io->bio;
+	struct bio_vec *bvec;
+	int i;
+
+	down_read(&io->io_rwsem);
+	if (!bio)
+		goto out;
+
+	bio_for_each_segment_all(bvec, bio, i) {
+		if (page == bvec->bv_page) {
+			up_read(&io->io_rwsem);
+			return true;
+		}
+	}
+
+out:
+	up_read(&io->io_rwsem);
+	return false;
+}
+
 void f2fs_wait_on_page_writeback(struct page *page,
 				enum page_type type)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
 	if (PageWriteback(page)) {
-		f2fs_submit_merged_bio(sbi, type, WRITE);
+		if (is_merged_page(sbi, page, type))
+			f2fs_submit_merged_bio(sbi, type, WRITE);
 		wait_on_page_writeback(page);
 	}
 }
@@ -920,11 +920,11 @@
 	sbi->por_doing = false;
 	spin_lock_init(&sbi->stat_lock);
  
-	mutex_init(&sbi->read_io.io_mutex);
+	init_rwsem(&sbi->read_io.io_rwsem);
 	sbi->read_io.sbi = sbi;
 	sbi->read_io.bio = NULL;
 	for (i = 0; i < NR_PAGE_TYPE; i++) {
-		mutex_init(&sbi->write_io[i].io_mutex);
+		init_rwsem(&sbi->write_io[i].io_rwsem);
 		sbi->write_io[i].sbi = sbi;
 		sbi->write_io[i].bio = NULL;
 	}
...	...	@@ -134,7 +134,7 @@
134	134
135	135	io = is_read_io(rw) ? &sbi->read_io : &sbi->write_io[btype];
136	136
137		- mutex_lock(&io->io_mutex);
	137	+ down_write(&io->io_rwsem);
138	138
139	139	/* change META to META_FLUSH in the checkpoint procedure */
140	140	if (type >= META_FLUSH) {
...	...	@@ -142,7 +142,7 @@
142	142	io->fio.rw = WRITE_FLUSH_FUA \| REQ_META \| REQ_PRIO;
143	143	}
144	144	__submit_merged_bio(io);
145		- mutex_unlock(&io->io_mutex);
	145	+ up_write(&io->io_rwsem);
146	146	}
147	147
148	148	/*
...	...	@@ -180,7 +180,7 @@
180	180
181	181	verify_block_addr(sbi, blk_addr);
182	182
183		- mutex_lock(&io->io_mutex);
	183	+ down_write(&io->io_rwsem);
184	184
185	185	if (!is_read)
186	186	inc_page_count(sbi, F2FS_WRITEBACK);
...	...	@@ -204,7 +204,7 @@
204	204
205	205	io->last_block_in_bio = blk_addr;
206	206
207		- mutex_unlock(&io->io_mutex);
	207	+ up_write(&io->io_rwsem);
208	208	trace_f2fs_submit_page_mbio(page, fio->rw, fio->type, blk_addr);
209	209	}
210	210
...	...	@@ -394,7 +394,7 @@
394	394	struct bio bio; / bios to merge */
395	395	sector_t last_block_in_bio; /* last block number */
396	396	struct f2fs_io_info fio; /* store buffered io info. */
397		- struct mutex io_mutex; /* mutex for bio */
	397	+ struct rw_semaphore io_rwsem; /* blocking op for bio */
398	398	};
399	399
400	400	struct f2fs_sb_info {
...	...	@@ -1046,12 +1046,38 @@
1046	1046	mutex_unlock(&curseg->curseg_mutex);
1047	1047	}
1048	1048
	1049	+static inline bool is_merged_page(struct f2fs_sb_info *sbi,
	1050	+ struct page *page, enum page_type type)
	1051	+{
	1052	+ enum page_type btype = PAGE_TYPE_OF_BIO(type);
	1053	+ struct f2fs_bio_info *io = &sbi->write_io[btype];
	1054	+ struct bio *bio = io->bio;
	1055	+ struct bio_vec *bvec;
	1056	+ int i;
	1057	+
	1058	+ down_read(&io->io_rwsem);
	1059	+ if (!bio)
	1060	+ goto out;
	1061	+
	1062	+ bio_for_each_segment_all(bvec, bio, i) {
	1063	+ if (page == bvec->bv_page) {
	1064	+ up_read(&io->io_rwsem);
	1065	+ return true;
	1066	+ }
	1067	+ }
	1068	+
	1069	+out:
	1070	+ up_read(&io->io_rwsem);
	1071	+ return false;
	1072	+}
	1073	+
1049	1074	void f2fs_wait_on_page_writeback(struct page *page,
1050	1075	enum page_type type)
1051	1076	{
1052	1077	struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
1053	1078	if (PageWriteback(page)) {
1054		- f2fs_submit_merged_bio(sbi, type, WRITE);
	1079	+ if (is_merged_page(sbi, page, type))
	1080	+ f2fs_submit_merged_bio(sbi, type, WRITE);
1055	1081	wait_on_page_writeback(page);
1056	1082	}
1057	1083	}
...	...	@@ -920,11 +920,11 @@
920	920	sbi->por_doing = false;
921	921	spin_lock_init(&sbi->stat_lock);
922	922
923		- mutex_init(&sbi->read_io.io_mutex);
	923	+ init_rwsem(&sbi->read_io.io_rwsem);
924	924	sbi->read_io.sbi = sbi;
925	925	sbi->read_io.bio = NULL;
926	926	for (i = 0; i < NR_PAGE_TYPE; i++) {
927		- mutex_init(&sbi->write_io[i].io_mutex);
	927	+ init_rwsem(&sbi->write_io[i].io_rwsem);
928	928	sbi->write_io[i].sbi = sbi;
929	929	sbi->write_io[i].bio = NULL;
930	930	}