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Commit 50d5c41c authored by Christoph Lameter's avatar Christoph Lameter Committed by Pekka Enberg
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slub: Do not use frozen page flag but a bit in the page counters 



Do not use a page flag for the frozen bit. It needs to be part
of the state that is handled with cmpxchg_double(). So use a bit
in the counter struct in the page struct for that purpose.

Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
parent 7e0528da

include/linux/mm_types.h

+3 −2
Original line number Diff line number Diff line
@@ -41,8 +41,9 @@ struct page { 
					 * & limit reverse map searches.

					 */

		struct {		/* SLUB */

			u16 inuse;

			u16 objects;

			unsigned inuse:16;

			unsigned objects:15;

			unsigned frozen:1;

		};

	};

	union {

include/linux/page-flags.h

+0 −5
Original line number Diff line number Diff line
@@ -124,9 +124,6 @@ enum pageflags { 


	/* SLOB */

	PG_slob_free = PG_private,



	/* SLUB */

	PG_slub_frozen = PG_active,

};



#ifndef __GENERATING_BOUNDS_H
@@ -212,8 +209,6 @@ PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked) 


__PAGEFLAG(SlobFree, slob_free)



__PAGEFLAG(SlubFrozen, slub_frozen)



/*

 * Private page markings that may be used by the filesystem that owns the page

 * for its own purposes.

mm/slub.c

+6 −6
Original line number Diff line number Diff line
@@ -166,7 +166,7 @@ static inline int kmem_cache_debug(struct kmem_cache *s) 


#define OO_SHIFT	16

#define OO_MASK		((1 << OO_SHIFT) - 1)

#define MAX_OBJS_PER_PAGE	65535 /* since page.objects is u16 */

#define MAX_OBJS_PER_PAGE	32767 /* since page.objects is u15 */



/* Internal SLUB flags */

#define __OBJECT_POISON		0x80000000UL /* Poison object */
@@ -1025,7 +1025,7 @@ static noinline int free_debug_processing(struct kmem_cache *s, 
	}



	/* Special debug activities for freeing objects */

	if (!PageSlubFrozen(page) && !page->freelist)

	if (!page->frozen && !page->freelist)

		remove_full(s, page);

	if (s->flags & SLAB_STORE_USER)

		set_track(s, object, TRACK_FREE, addr);
@@ -1424,7 +1424,7 @@ static inline int lock_and_freeze_slab(struct kmem_cache_node *n, 
{

	if (slab_trylock(page)) {

		__remove_partial(n, page);

		__SetPageSlubFrozen(page);

		page->frozen = 1;

		return 1;

	}

	return 0;
@@ -1538,7 +1538,7 @@ static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail) 
{

	struct kmem_cache_node *n = get_node(s, page_to_nid(page));



	__ClearPageSlubFrozen(page);

	page->frozen = 0;

	if (page->inuse) {



		if (page->freelist) {
@@ -1868,7 +1868,7 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, 
			flush_slab(s, c);



		slab_lock(page);

		__SetPageSlubFrozen(page);

		page->frozen = 1;

		c->node = page_to_nid(page);

		c->page = page;

		goto load_freelist;
@@ -2048,7 +2048,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page, 
	page->freelist = object;

	page->inuse--;



	if (unlikely(PageSlubFrozen(page))) {

	if (unlikely(page->frozen)) {

		stat(s, FREE_FROZEN);

		goto out_unlock;

	}