From 7f9838fd01833ffb30177d964983076924344c9e Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 21 Jul 2011 19:59:22 -0400 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/dir.c | 6 ++++++ fs/sysfs/inode.c | 14 +------------- fs/sysfs/sysfs.h | 2 ++ 3 files changed, 9 insertions(+), 13 deletions(-) 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 @@ static void sysfs_link_sibling(struct sysfs_dirent *sd) 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 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd) { 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) { diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index e3f091a..1ee18c8 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -202,18 +202,6 @@ static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) inode->i_ctime = iattr->ia_ctime; } -static int sysfs_count_nlink(struct sysfs_dirent *sd) -{ - struct sysfs_dirent *child; - int nr = 0; - - for (child = sd->s_dir.children; child; child = child->s_sibling) - if (sysfs_type(child) == SYSFS_DIR) - nr++; - - return nr + 2; -} - static void sysfs_refresh_inode(struct sysfs_dirent *sd, struct inode *inode) { struct sysfs_inode_attrs *iattrs = sd->s_iattr; @@ -230,7 +218,7 @@ static void sysfs_refresh_inode(struct sysfs_dirent *sd, struct inode *inode) } if (sysfs_type(sd) == SYSFS_DIR) - inode->i_nlink = sysfs_count_nlink(sd); + inode->i_nlink = sd->s_dir.subdirs + 2; } int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 845ab3a..6348e2c 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -19,6 +19,8 @@ struct sysfs_elem_dir { struct kobject *kobj; /* children list starts here and goes through sd->s_sibling */ struct sysfs_dirent *children; + + unsigned long subdirs; }; struct sysfs_elem_symlink { -- 2.7.4