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kobject: Introduce kset_find_obj_hinted.

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One call chain getting to kset_find_obj is:
  link_mem_sections()
    find_mem_section()
      kset_find_obj()

This is done during boot.  The memory sections were added in a linearly
increasing order and link_mem_sections tends to utilize them in that
same linear order.

Introduce a kset_find_obj_hinted which is passed the result of the
previous kset_find_obj which it uses for a quick "is the next object
our desired object" check before falling back to the old behavior.

Signed-off-by: Robin Holt <holt@sgi.com>
To: Robert P. J. Day <rpjday@crashcourse.ca>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Robin Holt 2010-09-29 14:00:54 -05:00 committed by Greg Kroah-Hartman
parent ead454feb6
commit c25d1dfbd4
2 changed files with 41 additions and 0 deletions
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2
include/linux/kobject.h
View File

@ -191,6 +191,8 @@ static inline struct kobj_type *get_ktype(struct kobject *kobj)
}
extern struct kobject *kset_find_obj(struct kset *, const char *);
extern struct kobject *kset_find_obj_hinted(struct kset *, const char *,
struct kobject *);
/* The global /sys/kernel/ kobject for people to chain off of */
extern struct kobject *kernel_kobj;

39
lib/kobject.c
View File

@ -745,18 +745,57 @@ void kset_unregister(struct kset *k)
* take a reference and return the object.
*/
struct kobject *kset_find_obj(struct kset *kset, const char *name)
{
return kset_find_obj_hinted(kset, name, NULL);
}
/**
* kset_find_obj_hinted - search for object in kset given a predecessor hint.
* @kset: kset we're looking in.
* @name: object's name.
* @hint: hint to possible object's predecessor.
*
* Check the hint's next object and if it is a match return it directly,
* otherwise, fall back to the behavior of kset_find_obj(). Either way
* a reference for the returned object is held and the reference on the
* hinted object is released.
*/
struct kobject *kset_find_obj_hinted(struct kset *kset, const char *name,
struct kobject *hint)
{
struct kobject *k;
struct kobject *ret = NULL;
spin_lock(&kset->list_lock);
if (!hint)
goto slow_search;
/* end of list detection */
if (hint->entry.next == kset->list.next)
goto slow_search;
k = container_of(hint->entry.next, struct kobject, entry);
if (!kobject_name(k) || strcmp(kobject_name(k), name))
goto slow_search;
ret = kobject_get(k);
goto unlock_exit;
slow_search:
list_for_each_entry(k, &kset->list, entry) {
if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
ret = kobject_get(k);
break;
}
}
unlock_exit:
spin_unlock(&kset->list_lock);
if (hint)
kobject_put(hint);
return ret;
}