sysfs: use singly-linked list for sysfs_dirent tree
Make sysfs_dirent use singly linked list for its tree structure.
sysfs_link_sibling() and sysfs_unlink_sibling() functions are added to
handle simpler cases. It adds some complexity and cpu cycle overhead
but reduced memory footprint is worthwhile on big machines.
This change reduces the sizeof sysfs_dirent from 104 to 88 on 64bit
and from 60 to 52 on 32bit.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index ae006b0..6f8aaf3 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -23,8 +23,8 @@
atomic_t s_count;
atomic_t s_active;
struct sysfs_dirent * s_parent;
- struct list_head s_sibling;
- struct list_head s_children;
+ struct sysfs_dirent * s_sibling;
+ struct sysfs_dirent * s_children;
const char * s_name;
union {