f2fs: move f2fs to use reader-unfair rwsems

f2fs rw_semaphores work better if writers can starve readers,
especially for the checkpoint thread, because writers are strictly
more important than reader threads. This prevents significant priority
inversion between low-priority readers that blocked while trying to
acquire the read lock and a second acquisition of the write lock that
might be blocking high priority work.

Signed-off-by: Tim Murray <timmurray@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 28 insertions, 28 deletions

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 76e6a3df9aba..9af6c20532ec 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1355,16 +1355,16 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb)
 	/* Initialize f2fs-specific inode info */
 	atomic_set(&fi->dirty_pages, 0);
 	atomic_set(&fi->i_compr_blocks, 0);
-	init_rwsem(&fi->i_sem);
+	init_f2fs_rwsem(&fi->i_sem);
 	spin_lock_init(&fi->i_size_lock);
 	INIT_LIST_HEAD(&fi->dirty_list);
 	INIT_LIST_HEAD(&fi->gdirty_list);
 	INIT_LIST_HEAD(&fi->inmem_ilist);
 	INIT_LIST_HEAD(&fi->inmem_pages);
 	mutex_init(&fi->inmem_lock);
-	init_rwsem(&fi->i_gc_rwsem[READ]);
-	init_rwsem(&fi->i_gc_rwsem[WRITE]);
-	init_rwsem(&fi->i_xattr_sem);
+	init_f2fs_rwsem(&fi->i_gc_rwsem[READ]);
+	init_f2fs_rwsem(&fi->i_gc_rwsem[WRITE]);
+	init_f2fs_rwsem(&fi->i_xattr_sem);
 
 	/* Will be used by directory only */
 	fi->i_dir_level = F2FS_SB(sb)->dir_level;
@@ -2088,7 +2088,7 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
 	f2fs_update_time(sbi, DISABLE_TIME);
 
 	while (!f2fs_time_over(sbi, DISABLE_TIME)) {
-		down_write(&sbi->gc_lock);
+		f2fs_down_write(&sbi->gc_lock);
 		err = f2fs_gc(sbi, true, false, false, NULL_SEGNO);
 		if (err == -ENODATA) {
 			err = 0;
@@ -2110,7 +2110,7 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
 		goto restore_flag;
 	}
 
-	down_write(&sbi->gc_lock);
+	f2fs_down_write(&sbi->gc_lock);
 	cpc.reason = CP_PAUSE;
 	set_sbi_flag(sbi, SBI_CP_DISABLED);
 	err = f2fs_write_checkpoint(sbi, &cpc);
@@ -2122,7 +2122,7 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
 	spin_unlock(&sbi->stat_lock);
 
 out_unlock:
-	up_write(&sbi->gc_lock);
+	f2fs_up_write(&sbi->gc_lock);
 restore_flag:
 	sbi->sb->s_flags = s_flags;	/* Restore SB_RDONLY status */
 	return err;
@@ -2142,12 +2142,12 @@ static void f2fs_enable_checkpoint(struct f2fs_sb_info *sbi)
 	if (unlikely(retry < 0))
 		f2fs_warn(sbi, "checkpoint=enable has some unwritten data.");
 
-	down_write(&sbi->gc_lock);
+	f2fs_down_write(&sbi->gc_lock);
 	f2fs_dirty_to_prefree(sbi);
 
 	clear_sbi_flag(sbi, SBI_CP_DISABLED);
 	set_sbi_flag(sbi, SBI_IS_DIRTY);
-	up_write(&sbi->gc_lock);
+	f2fs_up_write(&sbi->gc_lock);
 
 	f2fs_sync_fs(sbi->sb, 1);
 }
@@ -2707,18 +2707,18 @@ int f2fs_quota_sync(struct super_block *sb, int type)
 		/*
 		 * do_quotactl
 		 *  f2fs_quota_sync
-		 *  down_read(quota_sem)
+		 *  f2fs_down_read(quota_sem)
 		 *  dquot_writeback_dquots()
 		 *  f2fs_dquot_commit
 		 *			      block_operation
-		 *			      down_read(quota_sem)
+		 *			      f2fs_down_read(quota_sem)
 		 */
 		f2fs_lock_op(sbi);
-		down_read(&sbi->quota_sem);
+		f2fs_down_read(&sbi->quota_sem);
 
 		ret = f2fs_quota_sync_file(sbi, cnt);
 
-		up_read(&sbi->quota_sem);
+		f2fs_up_read(&sbi->quota_sem);
 		f2fs_unlock_op(sbi);
 
 		inode_unlock(dqopt->files[cnt]);
@@ -2843,11 +2843,11 @@ static int f2fs_dquot_commit(struct dquot *dquot)
 	struct f2fs_sb_info *sbi = F2FS_SB(dquot->dq_sb);
 	int ret;
 
-	down_read_nested(&sbi->quota_sem, SINGLE_DEPTH_NESTING);
+	f2fs_down_read_nested(&sbi->quota_sem, SINGLE_DEPTH_NESTING);
 	ret = dquot_commit(dquot);
 	if (ret < 0)
 		set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
-	up_read(&sbi->quota_sem);
+	f2fs_up_read(&sbi->quota_sem);
 	return ret;
 }
 
@@ -2856,11 +2856,11 @@ static int f2fs_dquot_acquire(struct dquot *dquot)
 	struct f2fs_sb_info *sbi = F2FS_SB(dquot->dq_sb);
 	int ret;
 
-	down_read(&sbi->quota_sem);
+	f2fs_down_read(&sbi->quota_sem);
 	ret = dquot_acquire(dquot);
 	if (ret < 0)
 		set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
-	up_read(&sbi->quota_sem);
+	f2fs_up_read(&sbi->quota_sem);
 	return ret;
 }
 
@@ -3601,14 +3601,14 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
 
 	INIT_LIST_HEAD(&sbi->s_list);
 	mutex_init(&sbi->umount_mutex);
-	init_rwsem(&sbi->io_order_lock);
+	init_f2fs_rwsem(&sbi->io_order_lock);
 	spin_lock_init(&sbi->cp_lock);
 
 	sbi->dirty_device = 0;
 	spin_lock_init(&sbi->dev_lock);
 
-	init_rwsem(&sbi->sb_lock);
-	init_rwsem(&sbi->pin_sem);
+	init_f2fs_rwsem(&sbi->sb_lock);
+	init_f2fs_rwsem(&sbi->pin_sem);
 }
 
 static int init_percpu_info(struct f2fs_sb_info *sbi)
@@ -4067,11 +4067,11 @@ try_onemore:
 
 	/* init f2fs-specific super block info */
 	sbi->valid_super_block = valid_super_block;
-	init_rwsem(&sbi->gc_lock);
+	init_f2fs_rwsem(&sbi->gc_lock);
 	mutex_init(&sbi->writepages);
-	init_rwsem(&sbi->cp_global_sem);
-	init_rwsem(&sbi->node_write);
-	init_rwsem(&sbi->node_change);
+	init_f2fs_rwsem(&sbi->cp_global_sem);
+	init_f2fs_rwsem(&sbi->node_write);
+	init_f2fs_rwsem(&sbi->node_change);
 
 	/* disallow all the data/node/meta page writes */
 	set_sbi_flag(sbi, SBI_POR_DOING);
@@ -4092,18 +4092,18 @@ try_onemore:
 		}
 
 		for (j = HOT; j < n; j++) {
-			init_rwsem(&sbi->write_io[i][j].io_rwsem);
+			init_f2fs_rwsem(&sbi->write_io[i][j].io_rwsem);
 			sbi->write_io[i][j].sbi = sbi;
 			sbi->write_io[i][j].bio = NULL;
 			spin_lock_init(&sbi->write_io[i][j].io_lock);
 			INIT_LIST_HEAD(&sbi->write_io[i][j].io_list);
 			INIT_LIST_HEAD(&sbi->write_io[i][j].bio_list);
-			init_rwsem(&sbi->write_io[i][j].bio_list_lock);
+			init_f2fs_rwsem(&sbi->write_io[i][j].bio_list_lock);
 		}
 	}
 
-	init_rwsem(&sbi->cp_rwsem);
-	init_rwsem(&sbi->quota_sem);
+	init_f2fs_rwsem(&sbi->cp_rwsem);
+	init_f2fs_rwsem(&sbi->quota_sem);
 	init_waitqueue_head(&sbi->cp_wait);
 	init_sb_info(sbi);