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Commit 5f80b13a authored by Christoph Lameter's avatar Christoph Lameter Committed by Pekka Enberg
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slub: get_map() function to establish map of free objects in a slab 



The bit map of free objects in a slab page is determined in various functions
if debugging is enabled.

Provide a common function for that purpose.

Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
parent 33de04ec

mm/slub.c

+22 −12
Original line number Diff line number Diff line
@@ -271,10 +271,6 @@ static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) 
	for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\

			__p += (__s)->size)



/* Scan freelist */

#define for_each_free_object(__p, __s, __free) \

	for (__p = (__free); __p; __p = get_freepointer((__s), __p))



/* Determine object index from a given position */

static inline int slab_index(void *p, struct kmem_cache *s, void *addr)

{
@@ -330,6 +326,21 @@ static inline int oo_objects(struct kmem_cache_order_objects x) 
	return x.x & OO_MASK;

}



/*

 * Determine a map of object in use on a page.

 *

 * Slab lock or node listlock must be held to guarantee that the page does

 * not vanish from under us.

 */

static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)

{

	void *p;

	void *addr = page_address(page);



	for (p = page->freelist; p; p = get_freepointer(s, p))

		set_bit(slab_index(p, s, addr), map);

}



#ifdef CONFIG_SLUB_DEBUG

/*

 * Debug settings:
@@ -2673,9 +2684,8 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page, 
		return;

	slab_err(s, page, "%s", text);

	slab_lock(page);

	for_each_free_object(p, s, page->freelist)

		set_bit(slab_index(p, s, addr), map);



	get_map(s, page, map);

	for_each_object(p, s, addr, page->objects) {



		if (!test_bit(slab_index(p, s, addr), map)) {
@@ -3610,8 +3620,9 @@ static int validate_slab(struct kmem_cache *s, struct page *page, 
	/* Now we know that a valid freelist exists */

	bitmap_zero(map, page->objects);



	for_each_free_object(p, s, page->freelist) {

		set_bit(slab_index(p, s, addr), map);

	get_map(s, page, map);

	for_each_object(p, s, addr, page->objects) {

		if (test_bit(slab_index(p, s, addr), map))

			if (!check_object(s, page, p, SLUB_RED_INACTIVE))

				return 0;

	}
@@ -3821,8 +3832,7 @@ static void process_slab(struct loc_track *t, struct kmem_cache *s, 
	void *p;



	bitmap_zero(map, page->objects);

	for_each_free_object(p, s, page->freelist)

		set_bit(slab_index(p, s, addr), map);

	get_map(s, page, map);



	for_each_object(p, s, addr, page->objects)

		if (!test_bit(slab_index(p, s, addr), map))