path: root/fs/ext4/inline.c
diff options
authorZheng Liu <wenqing.lz@taobao.com>2014-07-15 10:10:04 -0400
committerTheodore Ts'o <tytso@mit.edu>2014-07-15 10:10:04 -0400
commit83447ccb4df6e6051027bedff2a8cfc6a52ebcf8 (patch)
tree92302fbc7d77b82d58ac0f2acda54c4bf4096a65 /fs/ext4/inline.c
parent590a141863f726216d452f26bdcc59d648fd7cb0 (diff)
ext4: make ext4_has_inline_data() as a inline function
Now ext4_has_inline_data() is used in wide spread codepaths. So we need to make it as a inline function to avoid burning some CPU cycles. Change in text size: text data bss dec hex filename before: 326110 19258 5528 350896 55ab0 fs/ext4/ext4.o after: 326227 19258 5528 351013 55b25 fs/ext4/ext4.o I use the following script to measure the CPU usage. #!/bin/bash shm_base='/dev/shm' img=${shm_base}/ext4-img mnt=/mnt/loop e2fsprgs_base=$HOME/e2fsprogs mkfs=${e2fsprgs_base}/misc/mke2fs fsck=${e2fsprgs_base}/e2fsck/e2fsck sudo umount $mnt dd if=/dev/zero of=$img bs=4k count=3145728 ${mkfs} -t ext4 -O inline_data -F $img sudo mount -t ext4 -o loop $img $mnt # start testing... testdir="${mnt}/testdir" mkdir $testdir cd $testdir echo "start testing..." for ((cnt=0;cnt<100;cnt++)); do for ((i=0;i<5;i++)); do for ((j=0;j<5;j++)); do for ((k=0;k<5;k++)); do for ((l=0;l<5;l++)); do mkdir -p $i/$j/$k/$l echo "$i-$j-$k-$l" > $i/$j/$k/$l/testfile done done done done ls -R $testdir > /dev/null rm -rf $testdir/* done The result of `perf top -G -U` is as below. vanilla: 13.92% [ext4] [k] ext4_do_update_inode 9.36% [ext4] [k] __ext4_get_inode_loc 4.07% [ext4] [k] ftrace_define_fields_ext4_writepages 3.83% [ext4] [k] __ext4_handle_dirty_metadata 3.42% [ext4] [k] ext4_get_inode_flags 2.71% [ext4] [k] ext4_mark_iloc_dirty 2.46% [ext4] [k] ftrace_define_fields_ext4_direct_IO_enter 2.26% [ext4] [k] ext4_get_inode_loc 2.22% [ext4] [k] ext4_has_inline_data [...] After applied the patch, we don't see ext4_has_inline_data() because it has been inlined and perf couldn't sample it. Although it doesn't mean that the CPU cycles can be saved but at least the overhead of function calls can be eliminated. So IMHO we'd better inline this function. Cc: Andreas Dilger <adilger.kernel@dilger.ca> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/inline.c')
1 files changed, 0 insertions, 6 deletions
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 645205d8ada6..141b6acbc51c 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -120,12 +120,6 @@ int ext4_get_max_inline_size(struct inode *inode)
return max_inline_size + EXT4_MIN_INLINE_DATA_SIZE;
-int ext4_has_inline_data(struct inode *inode)
- return ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA) &&
- EXT4_I(inode)->i_inline_off;
* this function does not take xattr_sem, which is OK because it is
* currently only used in a code path coming form ext4_iget, before