diff options
| -rw-r--r-- | include/linux/mm_types.h | 24 | ||||
| -rw-r--r-- | include/linux/slab.h | 9 | ||||
| -rw-r--r-- | include/linux/slab_def.h | 4 | ||||
| -rw-r--r-- | mm/slab.c | 571 |
4 files changed, 243 insertions, 365 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index faf4b7c1ad12..95bf0c5a7eb9 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -42,18 +42,22 @@ struct page { /* First double word block */ unsigned long flags; /* Atomic flags, some possibly * updated asynchronously */ - struct address_space *mapping; /* If low bit clear, points to - * inode address_space, or NULL. - * If page mapped as anonymous - * memory, low bit is set, and - * it points to anon_vma object: - * see PAGE_MAPPING_ANON below. - */ + union { + struct address_space *mapping; /* If low bit clear, points to + * inode address_space, or NULL. + * If page mapped as anonymous + * memory, low bit is set, and + * it points to anon_vma object: + * see PAGE_MAPPING_ANON below. + */ + void *s_mem; /* slab first object */ + }; + /* Second double word */ struct { union { pgoff_t index; /* Our offset within mapping. */ - void *freelist; /* slub/slob first free object */ + void *freelist; /* sl[aou]b first free object */ bool pfmemalloc; /* If set by the page allocator, * ALLOC_NO_WATERMARKS was set * and the low watermark was not @@ -109,6 +113,7 @@ struct page { }; atomic_t _count; /* Usage count, see below. */ }; + unsigned int active; /* SLAB */ }; }; @@ -130,6 +135,9 @@ struct page { struct list_head list; /* slobs list of pages */ struct slab *slab_page; /* slab fields */ + struct rcu_head rcu_head; /* Used by SLAB + * when destroying via RCU + */ }; /* Remainder is not double word aligned */ diff --git a/include/linux/slab.h b/include/linux/slab.h index 6c5cc0ea8713..caaad51fee1f 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -51,7 +51,14 @@ * } * rcu_read_unlock(); * - * See also the comment on struct slab_rcu in mm/slab.c. + * This is useful if we need to approach a kernel structure obliquely, + * from its address obtained without the usual locking. We can lock + * the structure to stabilize it and check it's still at the given address, + * only if we can be sure that the memory has not been meanwhile reused + * for some other kind of object (which our subsystem's lock might corrupt). + * + * rcu_read_lock before reading the address, then rcu_read_unlock after + * taking the spinlock within the structure expected at that address. */ #define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */ #define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */ diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h index cd401580bdd3..ca82e8ff89fa 100644 --- a/include/linux/slab_def.h +++ b/include/linux/slab_def.h @@ -41,8 +41,8 @@ struct kmem_cache { size_t colour; /* cache colouring range */ unsigned int colour_off; /* colour offset */ - struct kmem_cache *slabp_cache; - unsigned int slab_size; + struct kmem_cache *freelist_cache; + unsigned int freelist_size; /* constructor func */ void (*ctor)(void *obj); diff --git a/mm/slab.c b/mm/slab.c index 2580db062df9..a983e3084332 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -164,72 +164,6 @@ static bool pfmemalloc_active __read_mostly; /* - * kmem_bufctl_t: - * - * Bufctl's are used for linking objs within a slab - * linked offsets. - * - * This implementation relies on "struct page" for locating the cache & - * slab an object belongs to. - * This allows the bufctl structure to be small (one int), but limits - * the number of objects a slab (not a cache) can contain when off-slab - * bufctls are used. The limit is the size of the largest general cache - * that does not use off-slab slabs. - * For 32bit archs with 4 kB pages, is this 56. - * This is not serious, as it is only for large objects, when it is unwise - * to have too many per slab. - * Note: This limit can be raised by introducing a general cache whose size - * is less than 512 (PAGE_SIZE<<3), but greater than 256. - */ - -typedef unsigned int kmem_bufctl_t; -#define BUFCTL_END (((kmem_bufctl_t)(~0U))-0) -#define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1) -#define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2) -#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3) - -/* - * struct slab_rcu - * - * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to - * arrange for kmem_freepages to be called via RCU. This is useful if - * we need to approach a kernel structure obliquely, from its address - * obtained without the usual locking. We can lock the structure to - * stabilize it and check it's still at the given address, only if we - * can be sure that the memory has not been meanwhile reused for some - * other kind of object (which our subsystem's lock might corrupt). - * - * rcu_read_lock before reading the address, then rcu_read_unlock after - * taking the spinlock within the structure expected at that address. - */ -struct slab_rcu { - struct rcu_head head; - struct kmem_cache *cachep; - void *addr; -}; - -/* - * struct slab - * - * Manages the objs in a slab. Placed either at the beginning of mem allocated - * for a slab, or allocated from an general cache. - * Slabs are chained into three list: fully used, partial, fully free slabs. - */ -struct slab { - union { - struct { - struct list_head list; - unsigned long colouroff; - void *s_mem; /* including colour offset */ - unsigned int inuse; /* num of objs active in slab */ - kmem_bufctl_t free; - unsigned short nodeid; - }; - struct slab_rcu __slab_cover_slab_rcu; - }; -}; - -/* * struct array_cache * * Purpose: @@ -456,18 +390,10 @@ static inline struct kmem_cache *virt_to_cache(const void *obj) return page->slab_cache; } -static inline struct slab *virt_to_slab(const void *obj) -{ - struct page *page = virt_to_head_page(obj); - - VM_BUG_ON(!PageSlab(page)); - return page->slab_page; -} - -static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab, +static inline void *index_to_obj(struct kmem_cache *cache, struct page *page, unsigned int idx) { - return slab->s_mem + cache->size * idx; + return page->s_mem + cache->size * idx; } /* @@ -477,9 +403,9 @@ static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab, * reciprocal_divide(offset, cache->reciprocal_buffer_size) */ static inline unsigned int obj_to_index(const struct kmem_cache *cache, - const struct slab *slab, void *obj) + const struct page *page, void *obj) { - u32 offset = (obj - slab->s_mem); + u32 offset = (obj - page->s_mem); return reciprocal_divide(offset, cache->reciprocal_buffer_size); } @@ -641,7 +567,7 @@ static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep) static size_t slab_mgmt_size(size_t nr_objs, size_t align) { - return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align); + return ALIGN(nr_objs * sizeof(unsigned int), align); } /* @@ -660,8 +586,7 @@ static void cache_estimate(unsigned long gfporder, size_t buffer_size, * on it. For the latter case, the memory allocated for a * slab is used for: * - * - The struct slab - * - One kmem_bufctl_t for each object + * - One unsigned int for each object * - Padding to respect alignment of @align * - @buffer_size bytes for each object * @@ -674,8 +599,6 @@ static void cache_estimate(unsigned long gfporder, size_t buffer_size, mgmt_size = 0; nr_objs = slab_size / buffer_size; - if (nr_objs > SLAB_LIMIT) - nr_objs = SLAB_LIMIT; } else { /* * Ignore padding for the initial guess. The padding @@ -685,8 +608,7 @@ static void cache_estimate(unsigned long gfporder, size_t buffer_size, * into the memory allocation when taking the padding * into account. */ - nr_objs = (slab_size - sizeof(struct slab)) / - (buffer_size + sizeof(kmem_bufctl_t)); + nr_objs = (slab_size) / (buffer_size + sizeof(unsigned int)); /* * This calculated number will be either the right @@ -696,9 +618,6 @@ static void cache_estimate(unsigned long gfporder, size_t buffer_size, > slab_size) nr_objs--; - if (nr_objs > SLAB_LIMIT) - nr_objs = SLAB_LIMIT; - mgmt_size = slab_mgmt_size(nr_objs, align); } *num = nr_objs; @@ -829,10 +748,8 @@ static struct array_cache *alloc_arraycache(int node, int entries, return nc; } -static inline bool is_slab_pfmemalloc(struct slab *slabp) +static inline bool is_slab_pfmemalloc(struct page *page) { - struct page *page = virt_to_page(slabp->s_mem); - return PageSlabPfmemalloc(page); } @@ -841,23 +758,23 @@ static void recheck_pfmemalloc_active(struct kmem_cache *cachep, struct array_cache *ac) { struct kmem_cache_node *n = cachep->node[numa_mem_id()]; - struct slab *slabp; + struct page *page; unsigned long flags; if (!pfmemalloc_active) return; spin_lock_irqsave(&n->list_lock, flags); - list_for_each_entry(slabp, &n->slabs_full, list) - if (is_slab_pfmemalloc(slabp)) + list_for_each_entry(page, &n->slabs_full, lru) + if (is_slab_pfmemalloc(page)) goto out; - list_for_each_entry(slabp, &n->slabs_partial, list) - if (is_slab_pfmemalloc(slabp)) + list_for_each_entry(page, &n->slabs_partial, lru) + if (is_slab_pfmemalloc(page)) goto out; - list_for_each_entry(slabp, &n->slabs_free, list) - if (is_slab_pfmemalloc(slabp)) + list_for_each_entry(page, &n->slabs_free, lru) + if (is_slab_pfmemalloc(page)) goto out; pfmemalloc_active = false; @@ -897,8 +814,8 @@ static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac, */ n = cachep->node[numa_mem_id()]; if (!list_empty(&n->slabs_free) && force_refill) { - struct slab *slabp = virt_to_slab(objp); - ClearPageSlabPfmemalloc(virt_to_head_page(slabp->s_mem)); + struct page *page = virt_to_head_page(objp); + ClearPageSlabPfmemalloc(page); clear_obj_pfmemalloc(&objp); recheck_pfmemalloc_active(cachep, ac); return objp; @@ -1099,8 +1016,7 @@ static void drain_alien_cache(struct kmem_cache *cachep, static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) { - struct slab *slabp = virt_to_slab(objp); - int nodeid = slabp->nodeid; + int nodeid = page_to_nid(virt_to_page(objp)); struct kmem_cache_node *n; struct array_cache *alien = NULL; int node; @@ -1111,7 +1027,7 @@ static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) * Make sure we are not freeing a object from another node to the array * cache on this cpu. */ - if (likely(slabp->nodeid == node)) + if (likely(nodeid == node)) return 0; n = cachep->node[node]; @@ -1512,6 +1428,8 @@ void __init kmem_cache_init(void) { int i; + BUILD_BUG_ON(sizeof(((struct page *)NULL)->lru) < + sizeof(struct rcu_head)); kmem_cache = &kmem_cache_boot; setup_node_pointer(kmem_cache); @@ -1687,7 +1605,7 @@ static noinline void slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid) { struct kmem_cache_node *n; - struct slab *slabp; + struct page *page; unsigned long flags; int node; @@ -1706,15 +1624,15 @@ slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid) continue; spin_lock_irqsave(&n->list_lock, flags); - list_for_each_entry(slabp, &n->slabs_full, list) { + list_for_each_entry(page, &n->slabs_full, lru) { active_objs += cachep->num; active_slabs++; } - list_for_each_entry(slabp, &n->slabs_partial, list) { - active_objs += slabp->inuse; + list_for_each_entry(page, &n->slabs_partial, lru) { + active_objs += page->active; active_slabs++; } - list_for_each_entry(slabp, &n->slabs_free, list) + list_for_each_entry(page, &n->slabs_free, lru) num_slabs++; free_objects += n->free_objects; @@ -1736,19 +1654,11 @@ slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid) * did not request dmaable memory, we might get it, but that * would be relatively rare and ignorable. */ -static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) +static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, + int nodeid) { struct page *page; int nr_pages; - int i; - -#ifndef CONFIG_MMU - /* - * Nommu uses slab's for process anonymous memory allocations, and thus - * requires __GFP_COMP to properly refcount higher order allocations - */ - flags |= __GFP_COMP; -#endif flags |= cachep->allocflags; if (cachep->flags & SLAB_RECLAIM_ACCOUNT) @@ -1772,12 +1682,9 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) else add_zone_page_state(page_zone(page), NR_SLAB_UNRECLAIMABLE, nr_pages); - for (i = 0; i < nr_pages; i++) { - __SetPageSlab(page + i); - - if (page->pfmemalloc) - SetPageSlabPfmemalloc(page + i); - } + __SetPageSlab(page); + if (page->pfmemalloc) + SetPageSlabPfmemalloc(page); memcg_bind_pages(cachep, cachep->gfporder); if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) { @@ -1789,17 +1696,15 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) kmemcheck_mark_unallocated_pages(page, nr_pages); } - return page_address(page); + return page; } /* * Interface to system's page release. */ -static void kmem_freepages(struct kmem_cache *cachep, void *addr) +static void kmem_freepages(struct kmem_cache *cachep, struct page *page) { - unsigned long i = (1 << cachep->gfporder); - struct page *page = virt_to_page(addr); - const unsigned long nr_freed = i; + const unsigned long nr_freed = (1 << cachep->gfporder); kmemcheck_free_shadow(page, cachep->gfporder); @@ -1809,27 +1714,28 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr) else sub_zone_page_state(page_zone(page), NR_SLAB_UNRECLAIMABLE, nr_freed); - while (i--) { - BUG_ON(!PageSlab(page)); - __ClearPageSlabPfmemalloc(page); - __ClearPageSlab(page); - page++; - } + + BUG_ON(!PageSlab(page)); + __ClearPageSlabPfmemalloc(page); + __ClearPageSlab(page); + page_mapcount_reset(page); + page->mapping = NULL; memcg_release_pages(cachep, cachep->gfporder); if (current->reclaim_state) current->reclaim_state->reclaimed_slab += nr_freed; - free_memcg_kmem_pages((unsigned long)addr, cachep->gfporder); + __free_memcg_kmem_pages(page, cachep->gfporder); } static void kmem_rcu_free(struct rcu_head *head) { - struct slab_rcu *slab_rcu = (struct slab_rcu *)head; - struct kmem_cache *cachep = slab_rcu->cachep; + struct kmem_cache *cachep; + struct page *page; - kmem_freepages(cachep, slab_rcu->addr); - if (OFF_SLAB(cachep)) - kmem_cache_free(cachep->slabp_cache, slab_rcu); + page = container_of(head, struct page, rcu_head); + cachep = page->slab_cache; + + kmem_freepages(cachep, page); } #if DEBUG @@ -1978,19 +1884,19 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp) /* Print some data about the neighboring objects, if they * exist: */ - struct slab *slabp = virt_to_slab(objp); + struct page *page = virt_to_head_page(objp); unsigned int objnr; - objnr = obj_to_index(cachep, slabp, objp); + objnr = obj_to_index(cachep, page, objp); if (objnr) { - objp = index_to_obj(cachep, slabp, objnr - 1); + objp = index_to_obj(cachep, page, objnr - 1); realobj = (char *)objp + obj_offset(cachep); printk(KERN_ERR "Prev obj: start=%p, len=%d\n", realobj, size); print_objinfo(cachep, objp, 2); } if (objnr + 1 < cachep->num) { - objp = index_to_obj(cachep, slabp, objnr + 1); + objp = index_to_obj(cachep, page, objnr + 1); realobj = (char *)objp + obj_offset(cachep); printk(KERN_ERR "Next obj: start=%p, len=%d\n", realobj, size); @@ -2001,11 +1907,12 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp) #endif #if DEBUG -static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp) +static void slab_destroy_debugcheck(struct kmem_cache *cachep, + struct page *page) { int i; for (i = 0; i < cachep->num; i++) { - void *objp = index_to_obj(cachep, slabp, i); + void *objp = index_to_obj(cachep, page, i); if (cachep->flags & SLAB_POISON) { #ifdef CONFIG_DEBUG_PAGEALLOC @@ -2030,7 +1937,8 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slab } } #else -static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp) +static void slab_destroy_debugcheck(struct kmem_cache *cachep, + struct page *page) { } #endif @@ -2044,23 +1952,34 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slab * Before calling the slab must have been unlinked from the cache. The * cache-lock is not held/needed. */ -static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp) +static void slab_destroy(struct kmem_cache *cachep, struct page *page) { - void *addr = slabp->s_mem - slabp->colouroff; + void *freelist; - slab_destroy_debugcheck(cachep, slabp); + freelist = page->freelist; + slab_destroy_debugcheck(cachep, page); if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) { - struct slab_rcu *slab_rcu; + struct rcu_head *head; + + /* + * RCU free overloads the RCU head over the LRU. + * slab_page has been overloeaded over the LRU, + * however it is not used from now on so that + * we can use it safely. + */ + head = (void *)&page->rcu_head; + call_rcu(head, kmem_rcu_free); - slab_rcu = (struct slab_rcu *)slabp; - slab_rcu->cachep = cachep; - slab_rcu->addr = addr; - call_rcu(&slab_rcu->head, kmem_rcu_free); } else { - kmem_freepages(cachep, addr); - if (OFF_SLAB(cachep)) - kmem_cache_free(cachep->slabp_cache, slabp); + kmem_freepages(cachep, page); } + + /* + * From now on, we don't use freelist + * although actual page can be freed in rcu context + */ + if (OFF_SLAB(cachep)) + kmem_cache_free(cachep->freelist_cache, freelist); } /** @@ -2097,8 +2016,8 @@ static size_t calculate_slab_order(struct kmem_cache *cachep, * use off-slab slabs. Needed to avoid a possible * looping condition in cache_grow(). */ - offslab_limit = size - sizeof(struct slab); - offslab_limit /= sizeof(kmem_bufctl_t); + offslab_limit = size; + offslab_limit /= sizeof(unsigned int); if (num > offslab_limit) break; @@ -2220,7 +2139,7 @@ static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) int __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) { - size_t left_over, slab_size, ralign; + size_t left_over, freelist_size, ralign; gfp_t gfp; int err; size_t size = cachep->size; @@ -2339,22 +2258,21 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) if (!cachep->num) return -E2BIG; - slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t) - + sizeof(struct slab), cachep->align); + freelist_size = + ALIGN(cachep->num * sizeof(unsigned int), cachep->align); /* * If the slab has been placed off-slab, and we have enough space then * move it on-slab. This is at the expense of any extra colouring. */ - if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) { + if (flags & CFLGS_OFF_SLAB && left_over >= freelist_size) { flags &= ~CFLGS_OFF_SLAB; - left_over -= slab_size; + left_over -= freelist_size; } if (flags & CFLGS_OFF_SLAB) { /* really off slab. No need for manual alignment */ - slab_size = - cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab); + freelist_size = cachep->num * sizeof(unsigned int); #ifdef CONFIG_PAGE_POISONING /* If we're going to use the generic kernel_map_pages() @@ -2371,16 +2289,16 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) if (cachep->colour_off < cachep->align) cachep->colour_off = cachep->align; cachep->colour = left_over / cachep->colour_off; - cachep->slab_size = slab_size; + cachep->freelist_size = freelist_size; cachep->flags = flags; - cachep->allocflags = 0; + cachep->allocflags = __GFP_COMP; if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA)) cachep->allocflags |= GFP_DMA; cachep->size = size; cachep->reciprocal_buffer_size = reciprocal_value(size); if (flags & CFLGS_OFF_SLAB) { - cachep->slabp_cache = kmalloc_slab(slab_size, 0u); + cachep->freelist_cache = kmalloc_slab(freelist_size, 0u); /* * This is a possibility for one of the malloc_sizes caches. * But since we go off slab only for object size greater than @@ -2388,7 +2306,7 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) * this should not happen at all. * But leave a BUG_ON for some lucky dude. */ - BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache)); + BUG_ON(ZERO_OR_NULL_PTR(cachep->freelist_cache)); } err = setup_cpu_cache(cachep, gfp); @@ -2494,7 +2412,7 @@ static int drain_freelist(struct kmem_cache *cache, { struct list_head *p; int nr_freed; - struct slab *slabp; + struct page *page; nr_freed = 0; while (nr_freed < tofree && !list_empty(&n->slabs_free)) { @@ -2506,18 +2424,18 @@ static int drain_freelist(struct kmem_cache *cache, goto out; } - slabp = list_entry(p, struct slab, list); + page = list_entry(p, struct page, lru); #if DEBUG - BUG_ON(slabp->inuse); + BUG_ON(page->active); #endif - list_del(&slabp->list); + list_del(&page->lru); /* * Safe to drop the lock. The slab is no longer linked * to the cache. */ n->free_objects -= cache->num; spin_unlock_irq(&n->list_lock); - slab_destroy(cache, slabp); + slab_destroy(cache, page); nr_freed++; } out: @@ -2600,52 +2518,42 @@ int __kmem_cache_shutdown(struct kmem_cache *cachep) * descriptors in kmem_cache_create, we search through the malloc_sizes array. * If we are creating a malloc_sizes cache here it would not be visible to * kmem_find_general_cachep till the initialization is complete. - * Hence we cannot have slabp_cache same as the original cache. + * Hence we cannot have freelist_cache same as the original cache. */ -static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp, - int colour_off, gfp_t local_flags, - int nodeid) +static void *alloc_slabmgmt(struct kmem_cache *cachep, + struct page *page, int colour_off, + gfp_t local_flags, int nodeid) { - struct slab *slabp; + void *freelist; + void *addr = page_address(page); if (OFF_SLAB(cachep)) { /* Slab management obj is off-slab. */ - slabp = kmem_cache_alloc_node(cachep->slabp_cache, + freelist = kmem_cache_alloc_node(cachep->freelist_cache, local_flags, nodeid); - /* - * If the first object in the slab is leaked (it's allocated - * but no one has a reference to it), we want to make sure - * kmemleak does not treat the ->s_mem pointer as a reference - * to the object. Otherwise we will not report the leak. - */ - kmemleak_scan_area(&slabp->list, sizeof(struct list_head), - local_flags); - if (!slabp) + if (!freelist) return NULL; } else { - slabp = objp + colour_off; - colour_off += cachep->slab_size; + freelist = addr + colour_off; + colour_off += cachep->freelist_size; } - slabp->inuse = 0; - slabp->colouroff = colour_off; - slabp->s_mem = objp + colour_off; - slabp->nodeid = nodeid; - slabp->free = 0; - return slabp; + page->active = 0; + page->s_mem = addr + colour_off; + return freelist; } -static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp) +static inline unsigned int *slab_freelist(struct page *page) { - return (kmem_bufctl_t *) (slabp + 1); + return (unsigned int *)(page->freelist); } static void cache_init_objs(struct kmem_cache *cachep, - struct slab *slabp) + struct page *page) { int i; for (i = 0; i < cachep->num; i++) { - void *objp = index_to_obj(cachep, slabp, i); + void *objp = index_to_obj(cachep, page, i); #if DEBUG /* need to poison the objs? */ if (cachep->flags & SLAB_POISON) @@ -2681,9 +2589,8 @@ static void cache_init_objs(struct kmem_cache *cachep, if (cachep->ctor) cachep->ctor(objp); #endif - slab_bufctl(slabp)[i] = i + 1; + slab_freelist(page)[i] = i; } - slab_bufctl(slabp)[i - 1] = BUFCTL_END; } static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags) @@ -2696,41 +2603,41 @@ static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags) } } -static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp, +static void *slab_get_obj(struct kmem_cache *cachep, struct page *page, int nodeid) { - void *objp = index_to_obj(cachep, slabp, slabp->free); - kmem_bufctl_t next; + void *objp; - slabp->inuse++; - next = slab_bufctl(slabp)[slabp->free]; + objp = index_to_obj(cachep, page, slab_freelist(page)[page->active]); + page->active++; #if DEBUG - slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE; - WARN_ON(slabp->nodeid != nodeid); + WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid); #endif - slabp->free = next; return objp; } -static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp, +static void slab_put_obj(struct kmem_cache *cachep, struct page *page, void *objp, int nodeid) { - unsigned int objnr = obj_to_index(cachep, slabp, objp); - + unsigned int objnr = obj_to_index(cachep, page, objp); #if DEBUG + unsigned int i; + /* Verify that the slab belongs to the intended node */ - WARN_ON(slabp->nodeid != nodeid); + WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid); - if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) { - printk(KERN_ERR "slab: double free detected in cache " - "'%s', objp %p\n", cachep->name, objp); - BUG(); + /* Verify double free bug */ + for (i = page->active; i < cachep->num; i++) { + if (slab_freelist(page)[i] == objnr) { + printk(KERN_ERR "slab: double free detected in cache " + "'%s', objp %p\n", cachep->name, objp); + BUG(); + } } #endif - slab_bufctl(slabp)[objnr] = slabp->free; - slabp->free = objnr; - slabp->inuse--; + page->active--; + slab_freelist(page)[page->active] = objnr; } /* @@ -2738,23 +2645,11 @@ static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp, * for the slab allocator to be able to lookup the cache and slab of a * virtual address for kfree, ksize, and slab debugging. */ -static void slab_map_pages(struct kmem_cache *cache, struct slab *slab, - void *addr) +static void slab_map_pages(struct kmem_cache *cache, struct page *page, + void *freelist) { - int nr_pages; - struct page *page; - - page = virt_to_page(addr); - - nr_pages = 1; - if (likely(!PageCompound(page))) - nr_pages <<= cache->gfporder; - - do { - page->slab_cache = cache; - page->slab_page = slab; - page++; - } while (--nr_pages); + page->slab_cache = cache; + page->freelist = freelist; } /* @@ -2762,9 +2657,9 @@ static void slab_map_pages(struct kmem_cache *cache, struct slab *slab, * kmem_cache_alloc() when there are no active objs left in a cache. */ static int cache_grow(struct kmem_cache *cachep, - gfp_t flags, int nodeid, void *objp) + gfp_t flags, int nodeid, struct page *page) { - struct slab *slabp; + void *freelist; size_t offset; gfp_t local_flags; struct kmem_cache_node *n; @@ -2805,20 +2700,20 @@ static int cache_grow(struct kmem_cache *cachep, * Get mem for the objs. Attempt to allocate a physical page from * 'nodeid'. */ - if (!objp) - objp = kmem_getpages(cachep, local_flags, nodeid); - if (!objp) + if (!page) + page = kmem_getpages(cachep, local_flags, nodeid); + if (!page) goto failed; /* Get slab management. */ - slabp = alloc_slabmgmt(cachep, objp, offset, + freelist = alloc_slabmgmt(cachep, page, offset, local_flags & ~GFP_CONSTRAINT_MASK, nodeid); - if (!slabp) + if (!freelist) goto opps1; - slab_map_pages(cachep, slabp, objp); + slab_map_pages(cachep, page, freelist); - cache_init_objs(cachep, slabp); + cache_init_objs(cachep, page); if (local_flags & __GFP_WAIT) local_irq_disable(); @@ -2826,13 +2721,13 @@ static int cache_grow(struct kmem_cache *cachep, spin_lock(&n->list_lock); /* Make slab active. */ - list_add_tail(&slabp->list, &(n->slabs_free)); + list_add_tail(&page->lru, &(n->slabs_free)); STATS_INC_GROWN(cachep); n->free_objects += cachep->num; spin_unlock(&n->list_lock); return 1; opps1: - kmem_freepages(cachep, objp); + kmem_freepages(cachep, page); failed: if (local_flags & __GFP_WAIT) local_irq_disable(); @@ -2880,9 +2775,8 @@ static inline void verify_redzone_free(struct kmem_cache *cache, void *obj) static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, unsigned long caller) { - struct page *page; unsigned int objnr; - struct slab *slabp; + struct page *page; BUG_ON(virt_to_cache(objp) != cachep); @@ -2890,8 +2784,6 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, kfree_debugcheck(objp); page = virt_to_head_page(objp); - slabp = page->slab_page; - if (cachep->flags & SLAB_RED_ZONE) { verify_redzone_free(cachep, objp); *dbg_redzone1(cachep, objp) = RED_INACTIVE; @@ -2900,14 +2792,11 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, if (cachep->flags & SLAB_STORE_USER) *dbg_userword(cachep, objp) = (void *)caller; - objnr = obj_to_index(cachep, slabp, objp); + objnr = obj_to_index(cachep, page, objp); BUG_ON(objnr >= cachep->num); - BUG_ON(objp != index_to_obj(cachep, slabp, objnr)); + BUG_ON(objp != index_to_obj(cachep, page, objnr)); -#ifdef CONFIG_DEBUG_SLAB_LEAK - slab_bufctl(slabp)[objnr] = BUFCTL_FREE; -#endif if (cachep->flags & SLAB_POISON) { #ifdef CONFIG_DEBUG_PAGEALLOC if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) { @@ -2924,33 +2813,9 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, return objp; } -static void check_slabp(struct kmem_cache *cachep, struct slab *slabp) -{ - kmem_bufctl_t i; - int entries = 0; - - /* Check slab's freelist to see if this obj is there. */ - for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) { - entries++; - if (entries > cachep->num || i >= cachep->num) - goto bad; - } - if (entries != cachep->num - slabp->inuse) { -bad: - printk(KERN_ERR "slab: Internal list corruption detected in " - "cache '%s'(%d), slabp %p(%d). Tainted(%s). Hexdump:\n", - cachep->name, cachep->num, slabp, slabp->inuse, - print_tainted()); - print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp, - sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t), - 1); - BUG(); - } -} #else #define kfree_debugcheck(x) do { } while(0) #define cache_free_debugcheck(x,objp,z) (objp) -#define check_slabp(x,y) do { } while(0) #endif static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags, @@ -2989,7 +2854,7 @@ retry: while (batchcount > 0) { struct list_head *entry; - struct slab *slabp; + struct page *page; /* Get slab alloc is to come from. */ entry = n->slabs_partial.next; if (entry == &n->slabs_partial) { @@ -2999,8 +2864,7 @@ retry: goto must_grow; } - slabp = list_entry(entry, struct slab, list); - check_slabp(cachep, slabp); + page = list_entry(entry, struct page, lru); check_spinlock_acquired(cachep); /* @@ -3008,24 +2872,23 @@ retry: * there must be at least one object available for * allocation. */ - BUG_ON(slabp->inuse >= cachep->num); + BUG_ON(page->active >= cachep->num); - while (slabp->inuse < cachep->num && batchcount--) { + while (page->active < cachep->num && batchcount--) { STATS_INC_ALLOCED(cachep); STATS_INC_ACTIVE(cachep); STATS_SET_HIGH(cachep); - ac_put_obj(cachep, ac, slab_get_obj(cachep, slabp, + ac_put_obj(cachep, ac, slab_get_obj(cachep, page, node)); } - check_slabp(cachep, slabp); /* move slabp to correct slabp list: */ - list_del(&slabp->list); - if (slabp->free == BUFCTL_END) - list_add(&slabp->list, &n->slabs_full); + list_del(&page->lru); + if (page->active == cachep->num) + list_add(&page->list, &n->slabs_full); else - list_add(&slabp->list, &n->slabs_partial); + list_add(&page->list, &n->slabs_partial); } must_grow: @@ -3097,16 +2960,6 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, *dbg_redzone1(cachep, objp) = RED_ACTIVE; *dbg_redzone2(cachep, objp) = RED_ACTIVE; } -#ifdef CONFIG_DEBUG_SLAB_LEAK - { - struct slab *slabp; - unsigned objnr; - - slabp = virt_to_head_page(objp)->slab_page; - objnr = (unsigned)(objp - slabp->s_mem) / cachep->size; - slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE; - } -#endif objp += obj_offset(cachep); if (cachep->ctor && cachep->flags & SLAB_POISON) cachep->ctor(objp); @@ -3248,18 +3101,20 @@ retry: * We may trigger various forms of reclaim on the allowed * set and go into memory reserves if necessary. */ + struct page *page; + if (local_flags & __GFP_WAIT) local_irq_enable(); kmem_flagcheck(cache, flags); - obj = kmem_getpages(cache, local_flags, numa_mem_id()); + page = kmem_getpages(cache, local_flags, numa_mem_id()); if (local_flags & __GFP_WAIT) local_irq_disable(); - if (obj) { + if (page) { /* * Insert into the appropriate per node queues */ - nid = page_to_nid(virt_to_page(obj)); - if (cache_grow(cache, flags, nid, obj)) { + nid = page_to_nid(page); + if (cache_grow(cache, flags, nid, page)) { obj = ____cache_alloc_node(cache, flags | GFP_THISNODE, nid); if (!obj) @@ -3288,7 +3143,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) { struct list_head *entry; - struct slab *slabp; + struct page *page; struct kmem_cache_node *n; void *obj; int x; @@ -3308,26 +3163,24 @@ retry: goto must_grow; } - slabp = list_entry(entry, struct slab, list); + page = list_entry(entry, struct page, lru); check_spinlock_acquired_node(cachep, nodeid); - check_slabp(cachep, slabp); STATS_INC_NODEALLOCS(cachep); STATS_INC_ACTIVE(cachep); STATS_SET_HIGH(cachep); - BUG_ON(slabp->inuse == cachep->num); + BUG_ON(page->active == cachep->num); - obj = slab_get_obj(cachep, slabp, nodeid); - check_slabp(cachep, slabp); + obj = slab_get_obj(cachep, page, nodeid); n->free_objects--; /* move slabp to correct slabp list: */ - list_del(&slabp->list); + list_del(&page->lru); - if (slabp->free == BUFCTL_END) - list_add(&slabp->list, &n->slabs_full); + if (page->active == cachep->num) + list_add(&page->lru, &n->slabs_full); else - list_add(&slabp->list, &n->slabs_partial); + list_add(&page->lru, &n->slabs_partial); spin_unlock(&n->list_lock); goto done; @@ -3477,23 +3330,21 @@ static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects, for (i = 0; i < nr_objects; i++) { void *objp; - struct slab *slabp; + struct page *page; clear_obj_pfmemalloc(&objpp[i]); objp = objpp[i]; - slabp = virt_to_slab(objp); + page = virt_to_head_page(objp); n = cachep->node[node]; - list_del(&slabp->list); + list_del(&page->lru); check_spinlock_acquired_node(cachep, node); - check_slabp(cachep, slabp); - slab_put_obj(cachep, slabp, objp, node); + slab_put_obj(cachep, page, objp, node); STATS_DEC_ACTIVE(cachep); n->free_objects++; - check_slabp(cachep, slabp); /* fixup slab chains */ - if (slabp->inuse == 0) { + if (page->active == 0) { if (n->free_objects > n->free_limit) { n->free_objects -= cachep->num; /* No need to drop any previously held @@ -3502,16 +3353,16 @@ static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects, * a different cache, refer to comments before * alloc_slabmgmt. */ - slab_destroy(cachep, slabp); + slab_destroy(cachep, page); } else { - list_add(&slabp->list, &n->slabs_free); + list_add(&page->lru, &n->slabs_free); } } else { /* Unconditionally move a slab to the end of the * partial list on free - maximum time for the * other objects to be freed, too. */ - list_add_tail(&slabp->list, &n->slabs_partial); + list_add_tail(&page->lru, &n->slabs_partial); } } } @@ -3551,10 +3402,10 @@ free_done: p = n->slabs_free.next; while (p != &(n->slabs_free)) { - struct slab *slabp; + struct page *page; - slabp = list_entry(p, struct slab, list); - BUG_ON(slabp->inuse); + page = list_entry(p, struct page, lru); + BUG_ON(page->active); i++; p = p->next; @@ -4158,7 +4009,7 @@ out: #ifdef CONFIG_SLABINFO void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo) { - struct slab *slabp; + struct page *page; unsigned long active_objs; unsigned long num_objs; unsigned long active_slabs = 0; @@ -4178,23 +4029,23 @@ void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo) check_irq_on(); spin_lock_irq(&n->list_lock); - list_for_each_entry(slabp, &n->slabs_full, list) { - if (slabp->inuse != cachep->num && !error) + list_for_each_entry(page, &n->slabs_full, lru) { + if (page->active != cachep->num && !error) error = "slabs_full accounting error"; active_objs += cachep->num; active_slabs++; } - list_for_each_entry(slabp, &n->slabs_partial, list) { - if (slabp->inuse == cachep->num && !error) - error = "slabs_partial inuse accounting error"; - if (!slabp->inuse && !error) - error = "slabs_partial/inuse accounting error"; - active_objs += slabp->inuse; + list_for_each_entry(page, &n->slabs_partial, lru) { + if (page->active == cachep->num && !error) + error = "slabs_partial accounting error"; + if (!page->active && !error) + error = "slabs_partial accounting error"; + active_objs += page->active; active_slabs++; } - list_for_each_entry(slabp, &n->slabs_free, list) { - if (slabp->inuse && !error) - error = "slabs_free/inuse accounting error"; + list_for_each_entry(page, &n->slabs_free, lru) { + if (page->active && !error) + error = "slabs_free accounting error"; num_slabs++; } free_objects += n->free_objects; @@ -4346,15 +4197,27 @@ static inline int add_caller(unsigned long *n, unsigned long v) return 1; } -static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s) +static void handle_slab(unsigned long *n, struct kmem_cache *c, + struct page *page) { void *p; - int i; + int i, j; + if (n[0] == n[1]) return; - for (i = 0, p = s->s_mem; i < c->num; i++, p += c->size) { - if (slab_bufctl(s)[i] != BUFCTL_ACTIVE) + for (i = 0, p = page->s_mem; i < c->num; i++, p += c->size) { + bool active = true; + + for (j = page->active; j < c->num; j++) { + /* Skip freed item */ + if (slab_freelist(page)[j] == i) { + active = false; + break; + } + } + if (!active) continue; + if (!add_caller(n, (unsigned long)*dbg_userword(c, p))) return; } @@ -4379,7 +4242,7 @@ static void show_symbol(struct seq_file *m, unsigned long address) static int leaks_show(struct seq_file *m, void *p) { struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list); - struct slab *slabp; + struct page *page; struct kmem_cache_node *n; const char *name; unsigned long *x = m->private; @@ -4403,10 +4266,10 @@ static int leaks_show(struct seq_file *m, void *p) check_irq_on(); spin_lock_irq(&n->list_lock); - list_for_each_entry(slabp, &n->slabs_full, list) - handle_slab(x, cachep, slabp); - list_for_each_entry(slabp, &n->slabs_partial, list) - handle_slab(x, cachep, slabp); + list_for_each_entry(page, &n->slabs_full, lru) + handle_slab(x, cachep, page); + list_for_each_entry(page, &n->slabs_partial, lru) + handle_slab(x, cachep, page); spin_unlock_irq(&n->list_lock); } name = cachep->name; |