sysfs: count subdirectories
sysfs: count subdirectories
This patch introduces a subdirectory counter for each sysfs directory.
Without the patch, sysfs_refresh_inode would walk all entries of the directory
to calculate the number of subdirectories.
This patch improves time of "ls -la /sys/block" when there are 10000 block
devices from 9 seconds to 0.19 seconds.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index ea9120a..7d240e6 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -47,6 +47,9 @@
BUG_ON(sd->s_sibling);
+ if (sysfs_type(sd) == SYSFS_DIR)
+ parent_sd->s_dir.subdirs++;
+
/* Store directory entries in order by ino. This allows
* readdir to properly restart without having to add a
* cursor into the s_dir.children list.
@@ -73,6 +76,9 @@
{
struct sysfs_dirent **pos;
+ if (sysfs_type(sd) == SYSFS_DIR)
+ sd->s_parent->s_dir.subdirs--;
+
for (pos = &sd->s_parent->s_dir.children; *pos;
pos = &(*pos)->s_sibling) {
if (*pos == sd) {