Messages in this thread Patch in this message | | | Date | Sun, 1 Nov 2009 11:33:09 -0500 | From | Benjamin LaHaise <> | Subject | [PATCH 2/3] sysfs directory scaling: count number of children dirs |
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sysfs_count_nlink() is a bottleneck during mass bring up of network interfaces. Eliminate this problem by tracking the number of directories.
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org> diff -u b/fs/sysfs/dir.c b/fs/sysfs/dir.c --- b/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -70,6 +70,7 @@ sd->s_sibling = *pos; sd->s_sibling_prev = prev; *pos = sd; + parent_sd->s_nr_children_dir += (sysfs_type(sd) == SYSFS_DIR); // rb tree insert new = &(parent_sd->s_dir.child_rb_root.rb_node); @@ -118,6 +119,7 @@ if (sd->s_sibling) sd->s_sibling->s_sibling_prev = prev; + sd->s_parent->s_nr_children_dir -= (sysfs_type(sd) == SYSFS_DIR); sd->s_sibling_prev = NULL; rb_erase(&sd->s_rb_node, &sd->s_parent->s_dir.child_rb_root); } diff -u b/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h --- b/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -71,6 +71,8 @@ ino_t s_ino; umode_t s_mode; struct sysfs_inode_attrs *s_iattr; + + int s_nr_children_dir; }; #define SD_DEACTIVATED_BIAS INT_MIN only in patch2: unchanged: --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -191,14 +191,7 @@ static struct lock_class_key sysfs_inode_imutex_key; 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; + return sd->s_nr_children_dir + 2; } static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
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