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authorTheodore Ts'o <tytso@mit.edu>2010-11-02 09:34:50 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-11-02 10:38:30 -0400
commiteb8abb927ae2fd1730e24ea94cd9527f3c086292 (patch)
treee0ae72934040e8d840db503c311ac070d9850bc8
parent7fe19da4ca38fc20cdbc7020fcf2eca8fc756410 (diff)
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ext4: Remove useless spinlock in ext4_getattr()
Linus noted, and complained to me, that doing while lots of "git diff"'s of kernel sources, these spinlocks were responsible for 27% of the spinlock cost on his two-processor system as reported by perf. Git was doing lots of parallel stats, and this was putting a lot of pressure on ext4_getattr(). A spinlock to protect a single memory-to-memory copy is pointless, so remove it. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/ext4/inode.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 19161647046..4d78342f3bf 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5410,9 +5410,7 @@ int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
* will return the blocks that include the delayed allocation
* blocks for this file.
*/
- spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
- spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
return 0;