From 7656c72b5a631452ace361037ccf8384454d0f72 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Wed, 9 May 2007 02:32:40 -0700 Subject: [PATCH] SLUB: add macros for scanning objects in a slab Scanning of objects happens in a number of functions. Consolidate that code. DECLARE_BITMAP instead of coding the declaration for bitmaps. Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slub.c | 75 ++++++++++++++++++++++++++++++++----------------------- 1 file changed, 44 insertions(+), 31 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 15189d826f8f..e97627b0733a 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -208,6 +208,38 @@ static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) #endif } +/* + * Slow version of get and set free pointer. + * + * This version requires touching the cache lines of kmem_cache which + * we avoid to do in the fast alloc free paths. There we obtain the offset + * from the page struct. + */ +static inline void *get_freepointer(struct kmem_cache *s, void *object) +{ + return *(void **)(object + s->offset); +} + +static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) +{ + *(void **)(object + s->offset) = fp; +} + +/* Loop over all objects in a slab */ +#define for_each_object(__p, __s, __addr) \ + for (__p = (__addr); __p < (__addr) + (__s)->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) +{ + return (p - addr) / s->size; +} + /* * Object debugging */ @@ -243,23 +275,6 @@ static void print_section(char *text, u8 *addr, unsigned int length) } } -/* - * Slow version of get and set free pointer. - * - * This version requires touching the cache lines of kmem_cache which - * we avoid to do in the fast alloc free paths. There we obtain the offset - * from the page struct. - */ -static void *get_freepointer(struct kmem_cache *s, void *object) -{ - return *(void **)(object + s->offset); -} - -static void set_freepointer(struct kmem_cache *s, void *object, void *fp) -{ - *(void **)(object + s->offset) = fp; -} - /* * Tracking user of a slab. */ @@ -852,7 +867,7 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) memset(start, POISON_INUSE, PAGE_SIZE << s->order); last = start; - for (p = start + s->size; p < end; p += s->size) { + for_each_object(p, s, start) { setup_object(s, page, last); set_freepointer(s, last, p); last = p; @@ -873,12 +888,10 @@ static void __free_slab(struct kmem_cache *s, struct page *page) int pages = 1 << s->order; if (unlikely(PageError(page) || s->dtor)) { - void *start = page_address(page); - void *end = start + (pages << PAGE_SHIFT); void *p; slab_pad_check(s, page); - for (p = start; p <= end - s->size; p += s->size) { + for_each_object(p, s, page_address(page)) { if (s->dtor) s->dtor(p, s, 0); check_object(s, page, p, 0); @@ -2583,7 +2596,7 @@ static int validate_slab(struct kmem_cache *s, struct page *page) { void *p; void *addr = page_address(page); - unsigned long map[BITS_TO_LONGS(s->objects)]; + DECLARE_BITMAP(map, s->objects); if (!check_slab(s, page) || !on_freelist(s, page, NULL)) @@ -2592,14 +2605,14 @@ static int validate_slab(struct kmem_cache *s, struct page *page) /* Now we know that a valid freelist exists */ bitmap_zero(map, s->objects); - for(p = page->freelist; p; p = get_freepointer(s, p)) { - set_bit((p - addr) / s->size, map); + for_each_free_object(p, s, page->freelist) { + set_bit(slab_index(p, s, addr), map); if (!check_object(s, page, p, 0)) return 0; } - for(p = addr; p < addr + s->objects * s->size; p += s->size) - if (!test_bit((p - addr) / s->size, map)) + for_each_object(p, s, addr) + if (!test_bit(slab_index(p, s, addr), map)) if (!check_object(s, page, p, 1)) return 0; return 1; @@ -2771,15 +2784,15 @@ static void process_slab(struct loc_track *t, struct kmem_cache *s, struct page *page, enum track_item alloc) { void *addr = page_address(page); - unsigned long map[BITS_TO_LONGS(s->objects)]; + DECLARE_BITMAP(map, s->objects); void *p; bitmap_zero(map, s->objects); - for (p = page->freelist; p; p = get_freepointer(s, p)) - set_bit((p - addr) / s->size, map); + for_each_free_object(p, s, page->freelist) + set_bit(slab_index(p, s, addr), map); - for (p = addr; p < addr + s->objects * s->size; p += s->size) - if (!test_bit((p - addr) / s->size, map)) { + for_each_object(p, s, addr) + if (!test_bit(slab_index(p, s, addr), map)) { void *addr = get_track(s, p, alloc)->addr; add_location(t, s, addr);