From: David Sterba <dsterba@suse.cz>
Date: Mon, 29 Sep 2014 23:33:33 +0000 (+0200)
Subject: btrfs: remove unlikely from data-dependent branches and slow paths
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ee39b432b4ac083acdafd7b4f156283722e3bf14;p=linux.git

btrfs: remove unlikely from data-dependent branches and slow paths

There are the branch hints that obviously depend on the data being
processed, the CPU predictor will do better job according to the actual
load. It also does not make sense to use the hints in slow paths that do
a lot of other operations like locking, waiting or IO.

Signed-off-by: David Sterba <dsterba@suse.cz>
---

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 44d04979f0717..ede740bfaac0e 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9694,7 +9694,7 @@ void btrfs_end_nocow_write(struct btrfs_root *root)
 
 int btrfs_start_nocow_write(struct btrfs_root *root)
 {
-	if (unlikely(atomic_read(&root->will_be_snapshoted)))
+	if (atomic_read(&root->will_be_snapshoted))
 		return 0;
 
 	percpu_counter_inc(&root->subv_writers->counter);
@@ -9702,7 +9702,7 @@ int btrfs_start_nocow_write(struct btrfs_root *root)
 	 * Make sure counter is updated before we check for snapshot creation.
 	 */
 	smp_mb();
-	if (unlikely(atomic_read(&root->will_be_snapshoted))) {
+	if (atomic_read(&root->will_be_snapshoted)) {
 		btrfs_end_nocow_write(root);
 		return 0;
 	}
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 29b147d46b0a1..a18ceabd99a87 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -452,7 +452,7 @@ static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
 		if (unlikely(copied == 0))
 			break;
 
-		if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
+		if (copied < PAGE_CACHE_SIZE - offset) {
 			offset += copied;
 		} else {
 			pg++;
@@ -1792,7 +1792,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	if (sync)
 		atomic_inc(&BTRFS_I(inode)->sync_writers);
 
-	if (unlikely(file->f_flags & O_DIRECT)) {
+	if (file->f_flags & O_DIRECT) {
 		num_written = __btrfs_direct_write(iocb, from, pos);
 	} else {
 		num_written = __btrfs_buffered_write(file, from, pos);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 998e67fdf2f6b..47d214560831a 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7802,9 +7802,9 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
 	atomic_inc(&dip->pending_bios);
 
 	while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
-		if (unlikely(map_length < submit_len + bvec->bv_len ||
+		if (map_length < submit_len + bvec->bv_len ||
 		    bio_add_page(bio, bvec->bv_page, bvec->bv_len,
-				 bvec->bv_offset) < bvec->bv_len)) {
+				 bvec->bv_offset) < bvec->bv_len) {
 			/*
 			 * inc the count before we submit the bio so
 			 * we know the end IO handler won't happen before
@@ -8017,8 +8017,8 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
 		ret = btrfs_delalloc_reserve_space(inode, count);
 		if (ret)
 			goto out;
-	} else if (unlikely(test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
-				     &BTRFS_I(inode)->runtime_flags))) {
+	} else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
+				     &BTRFS_I(inode)->runtime_flags)) {
 		inode_dio_done(inode);
 		flags = DIO_LOCKING | DIO_SKIP_HOLES;
 		wakeup = false;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0ff212757b955..f2c60cd70e63e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3167,7 +3167,7 @@ static void clone_update_extent_map(struct inode *inode,
 					em->start + em->len - 1, 0);
 	}
 
-	if (unlikely(ret))
+	if (ret)
 		set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
 			&BTRFS_I(inode)->runtime_flags);
 }
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 16d0c1b62b3ef..8eded14e8c5c4 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -418,7 +418,7 @@ start_transaction(struct btrfs_root *root, u64 num_items, unsigned int type,
 		/*
 		 * Do the reservation for the relocation root creation
 		 */
-		if (unlikely(need_reserve_reloc_root(root))) {
+		if (need_reserve_reloc_root(root)) {
 			num_bytes += root->nodesize;
 			reloc_reserved = true;
 		}