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 CPU 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@xxxxxxx> --- fs/ext4/inode.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 1916164..4d78342 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; -- 1.7.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
