From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Sat, 21 May 2016 05:50:29 +0000 (-0700)
Subject: f2fs: remove writepages lock
X-Git-Tag: v4.8-rc1~145^2~55
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b93f7712868648c0529eed6b568cea1493d3d9f9;p=karo-tx-linux.git

f2fs: remove writepages lock

This patch removes writepages lock.
We can improve multi-threading performance.

tiobench, 32 threads, 4KB write per fsync on SSD
Before: 25.88 MB/s
After: 28.03 MB/s

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 287582e12f8f..7132b0202860 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1443,7 +1443,6 @@ static int f2fs_write_data_pages(struct address_space *mapping,
 {
 	struct inode *inode = mapping->host;
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	bool locked = false;
 	int ret;
 	long diff;
 
@@ -1472,14 +1471,8 @@ static int f2fs_write_data_pages(struct address_space *mapping,
 
 	diff = nr_pages_to_write(sbi, DATA, wbc);
 
-	if (!S_ISDIR(inode->i_mode) && wbc->sync_mode == WB_SYNC_ALL) {
-		mutex_lock(&sbi->writepages);
-		locked = true;
-	}
 	ret = f2fs_write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
 	f2fs_submit_merged_bio_cond(sbi, inode, NULL, 0, DATA, WRITE);
-	if (locked)
-		mutex_unlock(&sbi->writepages);
 
 	remove_dirty_inode(inode);
 
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index f02a3572fff3..4365108d40b3 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -770,7 +770,6 @@ struct f2fs_sb_info {
 	struct mutex cp_mutex;			/* checkpoint procedure lock */
 	struct rw_semaphore cp_rwsem;		/* blocking FS operations */
 	struct rw_semaphore node_write;		/* locking node writes */
-	struct mutex writepages;		/* mutex for writepages() */
 	wait_queue_head_t cp_wait;
 	unsigned long last_time[MAX_TIME];	/* to store time in jiffies */
 	long interval_time[MAX_TIME];		/* to store thresholds */
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 55203f6a4e8b..a5b57390079c 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1630,7 +1630,6 @@ try_onemore:
 	sbi->raw_super = raw_super;
 	sbi->valid_super_block = valid_super_block;
 	mutex_init(&sbi->gc_mutex);
-	mutex_init(&sbi->writepages);
 	mutex_init(&sbi->cp_mutex);
 	init_rwsem(&sbi->node_write);