diff options
Diffstat (limited to 'kernel/mm/slub.c')
| -rw-r--r-- | kernel/mm/slub.c | 369 |
1 files changed, 298 insertions, 71 deletions
diff --git a/kernel/mm/slub.c b/kernel/mm/slub.c index 905e283d7..d304d8802 100644 --- a/kernel/mm/slub.c +++ b/kernel/mm/slub.c @@ -459,8 +459,10 @@ static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map) /* * Debug settings: */ -#ifdef CONFIG_SLUB_DEBUG_ON +#if defined(CONFIG_SLUB_DEBUG_ON) static int slub_debug = DEBUG_DEFAULT_FLAGS; +#elif defined(CONFIG_KASAN) +static int slub_debug = SLAB_STORE_USER; #else static int slub_debug; #endif @@ -1063,11 +1065,15 @@ bad: return 0; } +/* Supports checking bulk free of a constructed freelist */ static noinline struct kmem_cache_node *free_debug_processing( - struct kmem_cache *s, struct page *page, void *object, + struct kmem_cache *s, struct page *page, + void *head, void *tail, int bulk_cnt, unsigned long addr, unsigned long *flags) { struct kmem_cache_node *n = get_node(s, page_to_nid(page)); + void *object = head; + int cnt = 0; raw_spin_lock_irqsave(&n->list_lock, *flags); slab_lock(page); @@ -1075,6 +1081,9 @@ static noinline struct kmem_cache_node *free_debug_processing( if (!check_slab(s, page)) goto fail; +next_object: + cnt++; + if (!check_valid_pointer(s, page, object)) { slab_err(s, page, "Invalid object pointer 0x%p", object); goto fail; @@ -1105,8 +1114,19 @@ static noinline struct kmem_cache_node *free_debug_processing( if (s->flags & SLAB_STORE_USER) set_track(s, object, TRACK_FREE, addr); trace(s, page, object, 0); + /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */ init_object(s, object, SLUB_RED_INACTIVE); + + /* Reached end of constructed freelist yet? */ + if (object != tail) { + object = get_freepointer(s, object); + goto next_object; + } out: + if (cnt != bulk_cnt) + slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n", + bulk_cnt, cnt); + slab_unlock(page); /* * Keep node_lock to preserve integrity @@ -1202,7 +1222,7 @@ unsigned long kmem_cache_flags(unsigned long object_size, return flags; } -#else +#else /* !CONFIG_SLUB_DEBUG */ static inline void setup_object_debug(struct kmem_cache *s, struct page *page, void *object) {} @@ -1210,7 +1230,8 @@ static inline int alloc_debug_processing(struct kmem_cache *s, struct page *page, void *object, unsigned long addr) { return 0; } static inline struct kmem_cache_node *free_debug_processing( - struct kmem_cache *s, struct page *page, void *object, + struct kmem_cache *s, struct page *page, + void *head, void *tail, int bulk_cnt, unsigned long addr, unsigned long *flags) { return NULL; } static inline int slab_pad_check(struct kmem_cache *s, struct page *page) @@ -1269,7 +1290,7 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, { flags &= gfp_allowed_mask; lockdep_trace_alloc(flags); - might_sleep_if(flags & __GFP_WAIT); + might_sleep_if(gfpflags_allow_blocking(flags)); if (should_failslab(s->object_size, flags, s->flags)) return NULL; @@ -1277,14 +1298,21 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, return memcg_kmem_get_cache(s, flags); } -static inline void slab_post_alloc_hook(struct kmem_cache *s, - gfp_t flags, void *object) +static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, + size_t size, void **p) { + size_t i; + flags &= gfp_allowed_mask; - kmemcheck_slab_alloc(s, flags, object, slab_ksize(s)); - kmemleak_alloc_recursive(object, s->object_size, 1, s->flags, flags); + for (i = 0; i < size; i++) { + void *object = p[i]; + + kmemcheck_slab_alloc(s, flags, object, slab_ksize(s)); + kmemleak_alloc_recursive(object, s->object_size, 1, + s->flags, flags); + kasan_slab_alloc(s, object); + } memcg_kmem_put_cache(s); - kasan_slab_alloc(s, object); } static inline void slab_free_hook(struct kmem_cache *s, void *x) @@ -1312,6 +1340,29 @@ static inline void slab_free_hook(struct kmem_cache *s, void *x) kasan_slab_free(s, x); } +static inline void slab_free_freelist_hook(struct kmem_cache *s, + void *head, void *tail) +{ +/* + * Compiler cannot detect this function can be removed if slab_free_hook() + * evaluates to nothing. Thus, catch all relevant config debug options here. + */ +#if defined(CONFIG_KMEMCHECK) || \ + defined(CONFIG_LOCKDEP) || \ + defined(CONFIG_DEBUG_KMEMLEAK) || \ + defined(CONFIG_DEBUG_OBJECTS_FREE) || \ + defined(CONFIG_KASAN) + + void *object = head; + void *tail_obj = tail ? : head; + + do { + slab_free_hook(s, object); + } while ((object != tail_obj) && + (object = get_freepointer(s, object))); +#endif +} + static void setup_object(struct kmem_cache *s, struct page *page, void *object) { @@ -1334,16 +1385,15 @@ static inline struct page *alloc_slab_page(struct kmem_cache *s, flags |= __GFP_NOTRACK; - if (memcg_charge_slab(s, flags, order)) - return NULL; - if (node == NUMA_NO_NODE) page = alloc_pages(flags, order); else - page = alloc_pages_exact_node(node, flags, order); + page = __alloc_pages_node(node, flags, order); - if (!page) - memcg_uncharge_slab(s, order); + if (page && memcg_charge_slab(page, flags, order, s)) { + __free_pages(page, order); + page = NULL; + } return page; } @@ -1355,13 +1405,15 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) gfp_t alloc_gfp; void *start, *p; int idx, order; - bool enableirqs; + bool enableirqs = false; flags &= gfp_allowed_mask; - enableirqs = (flags & __GFP_WAIT) != 0; + if (gfpflags_allow_blocking(flags)) + enableirqs = true; #ifdef CONFIG_PREEMPT_RT_FULL - enableirqs |= system_state == SYSTEM_RUNNING; + if (system_state == SYSTEM_RUNNING) + enableirqs = true; #endif if (enableirqs) local_irq_enable(); @@ -1373,6 +1425,8 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) * so we fall-back to the minimum order allocation. */ alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL; + if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min)) + alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_DIRECT_RECLAIM; page = alloc_slab_page(s, alloc_gfp, node, oo); if (unlikely(!page)) { @@ -1485,8 +1539,7 @@ static void __free_slab(struct kmem_cache *s, struct page *page) page_mapcount_reset(page); if (current->reclaim_state) current->reclaim_state->reclaimed_slab += pages; - __free_pages(page, order); - memcg_uncharge_slab(s, order); + __free_kmem_pages(page, order); } static void free_delayed(struct list_head *h) @@ -1526,10 +1579,7 @@ static void free_slab(struct kmem_cache *s, struct page *page) VM_BUG_ON(s->reserved != sizeof(*head)); head = page_address(page) + offset; } else { - /* - * RCU free overloads the RCU head over the LRU - */ - head = (void *)&page->lru; + head = &page->rcu_head; } call_rcu(head, rcu_free_slab); @@ -2345,25 +2395,17 @@ static inline void *get_freelist(struct kmem_cache *s, struct page *page) * And if we were unable to get a new slab from the partial slab lists then * we need to allocate a new slab. This is the slowest path since it involves * a call to the page allocator and the setup of a new slab. + * + * Version of __slab_alloc to use when we know that interrupts are + * already disabled (which is the case for bulk allocation). */ -static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, - unsigned long addr, struct kmem_cache_cpu *c) +static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, + unsigned long addr, struct kmem_cache_cpu *c, + struct list_head *to_free) { struct slub_free_list *f; void *freelist; struct page *page; - unsigned long flags; - LIST_HEAD(tofree); - - local_irq_save(flags); -#ifdef CONFIG_PREEMPT - /* - * We may have been preempted and rescheduled on a different - * cpu before disabling interrupts. Need to reload cpu area - * pointer. - */ - c = this_cpu_ptr(s->cpu_slab); -#endif page = c->page; if (!page) @@ -2421,13 +2463,13 @@ load_freelist: VM_BUG_ON(!c->page->frozen); c->freelist = get_freepointer(s, freelist); c->tid = next_tid(c->tid); + out: f = this_cpu_ptr(&slub_free_list); raw_spin_lock(&f->lock); - list_splice_init(&f->list, &tofree); + list_splice_init(&f->list, to_free); raw_spin_unlock(&f->lock); - local_irq_restore(flags); - free_delayed(&tofree); + return freelist; new_slab: @@ -2444,7 +2486,7 @@ new_slab: if (unlikely(!freelist)) { slab_out_of_memory(s, gfpflags, node); - goto out; + return NULL; } page = c->page; @@ -2463,6 +2505,33 @@ new_slab: } /* + * Another one that disabled interrupt and compensates for possible + * cpu changes by refetching the per cpu area pointer. + */ +static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, + unsigned long addr, struct kmem_cache_cpu *c) +{ + void *p; + unsigned long flags; + LIST_HEAD(tofree); + + local_irq_save(flags); +#ifdef CONFIG_PREEMPT + /* + * We may have been preempted and rescheduled on a different + * cpu before disabling interrupts. Need to reload cpu area + * pointer. + */ + c = this_cpu_ptr(s->cpu_slab); +#endif + + p = ___slab_alloc(s, gfpflags, node, addr, c, &tofree); + local_irq_restore(flags); + free_delayed(&tofree); + return p; +} + +/* * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc) * have the fastpath folded into their functions. So no function call * overhead for requests that can be satisfied on the fastpath. @@ -2475,7 +2544,7 @@ new_slab: static __always_inline void *slab_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node, unsigned long addr) { - void **object; + void *object; struct kmem_cache_cpu *c; struct page *page; unsigned long tid; @@ -2554,7 +2623,7 @@ redo: if (unlikely(gfpflags & __GFP_ZERO) && object) memset(object, 0, s->object_size); - slab_post_alloc_hook(s, gfpflags, object); + slab_post_alloc_hook(s, gfpflags, 1, &object); return object; } @@ -2625,10 +2694,11 @@ EXPORT_SYMBOL(kmem_cache_alloc_node_trace); * handling required then we can return immediately. */ static void __slab_free(struct kmem_cache *s, struct page *page, - void *x, unsigned long addr) + void *head, void *tail, int cnt, + unsigned long addr) + { void *prior; - void **object = (void *)x; int was_frozen; struct page new; unsigned long counters; @@ -2638,7 +2708,8 @@ static void __slab_free(struct kmem_cache *s, struct page *page, stat(s, FREE_SLOWPATH); if (kmem_cache_debug(s) && - !(n = free_debug_processing(s, page, x, addr, &flags))) + !(n = free_debug_processing(s, page, head, tail, cnt, + addr, &flags))) return; do { @@ -2648,10 +2719,10 @@ static void __slab_free(struct kmem_cache *s, struct page *page, } prior = page->freelist; counters = page->counters; - set_freepointer(s, object, prior); + set_freepointer(s, tail, prior); new.counters = counters; was_frozen = new.frozen; - new.inuse--; + new.inuse -= cnt; if ((!new.inuse || !prior) && !was_frozen) { if (kmem_cache_has_cpu_partial(s) && !prior) { @@ -2682,7 +2753,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page, } while (!cmpxchg_double_slab(s, page, prior, counters, - object, new.counters, + head, new.counters, "__slab_free")); if (likely(!n)) { @@ -2747,22 +2818,27 @@ slab_empty: * * If fastpath is not possible then fall back to __slab_free where we deal * with all sorts of special processing. + * + * Bulk free of a freelist with several objects (all pointing to the + * same page) possible by specifying head and tail ptr, plus objects + * count (cnt). Bulk free indicated by tail pointer being set. */ -static __always_inline void slab_free(struct kmem_cache *s, - struct page *page, void *x, unsigned long addr) +static __always_inline void slab_free(struct kmem_cache *s, struct page *page, + void *head, void *tail, int cnt, + unsigned long addr) { - void **object = (void *)x; + void *tail_obj = tail ? : head; struct kmem_cache_cpu *c; unsigned long tid; - slab_free_hook(s, x); + slab_free_freelist_hook(s, head, tail); redo: /* * Determine the currently cpus per cpu slab. * The cpu may change afterward. However that does not matter since * data is retrieved via this pointer. If we are on the same cpu - * during the cmpxchg then the free will succedd. + * during the cmpxchg then the free will succeed. */ do { tid = this_cpu_read(s->cpu_slab->tid); @@ -2774,19 +2850,19 @@ redo: barrier(); if (likely(page == c->page)) { - set_freepointer(s, object, c->freelist); + set_freepointer(s, tail_obj, c->freelist); if (unlikely(!this_cpu_cmpxchg_double( s->cpu_slab->freelist, s->cpu_slab->tid, c->freelist, tid, - object, next_tid(tid)))) { + head, next_tid(tid)))) { note_cmpxchg_failure("slab_free", s, tid); goto redo; } stat(s, FREE_FASTPATH); } else - __slab_free(s, page, x, addr); + __slab_free(s, page, head, tail_obj, cnt, addr); } @@ -2795,11 +2871,168 @@ void kmem_cache_free(struct kmem_cache *s, void *x) s = cache_from_obj(s, x); if (!s) return; - slab_free(s, virt_to_head_page(x), x, _RET_IP_); + slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_); trace_kmem_cache_free(_RET_IP_, x); } EXPORT_SYMBOL(kmem_cache_free); +struct detached_freelist { + struct page *page; + void *tail; + void *freelist; + int cnt; +}; + +/* + * This function progressively scans the array with free objects (with + * a limited look ahead) and extract objects belonging to the same + * page. It builds a detached freelist directly within the given + * page/objects. This can happen without any need for + * synchronization, because the objects are owned by running process. + * The freelist is build up as a single linked list in the objects. + * The idea is, that this detached freelist can then be bulk + * transferred to the real freelist(s), but only requiring a single + * synchronization primitive. Look ahead in the array is limited due + * to performance reasons. + */ +static int build_detached_freelist(struct kmem_cache *s, size_t size, + void **p, struct detached_freelist *df) +{ + size_t first_skipped_index = 0; + int lookahead = 3; + void *object; + + /* Always re-init detached_freelist */ + df->page = NULL; + + do { + object = p[--size]; + } while (!object && size); + + if (!object) + return 0; + + /* Start new detached freelist */ + set_freepointer(s, object, NULL); + df->page = virt_to_head_page(object); + df->tail = object; + df->freelist = object; + p[size] = NULL; /* mark object processed */ + df->cnt = 1; + + while (size) { + object = p[--size]; + if (!object) + continue; /* Skip processed objects */ + + /* df->page is always set at this point */ + if (df->page == virt_to_head_page(object)) { + /* Opportunity build freelist */ + set_freepointer(s, object, df->freelist); + df->freelist = object; + df->cnt++; + p[size] = NULL; /* mark object processed */ + + continue; + } + + /* Limit look ahead search */ + if (!--lookahead) + break; + + if (!first_skipped_index) + first_skipped_index = size + 1; + } + + return first_skipped_index; +} + + +/* Note that interrupts must be enabled when calling this function. */ +void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p) +{ + if (WARN_ON(!size)) + return; + + do { + struct detached_freelist df; + struct kmem_cache *s; + + /* Support for memcg */ + s = cache_from_obj(orig_s, p[size - 1]); + + size = build_detached_freelist(s, size, p, &df); + if (unlikely(!df.page)) + continue; + + slab_free(s, df.page, df.freelist, df.tail, df.cnt, _RET_IP_); + } while (likely(size)); +} +EXPORT_SYMBOL(kmem_cache_free_bulk); + +/* Note that interrupts must be enabled when calling this function. */ +int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, + void **p) +{ + struct kmem_cache_cpu *c; + LIST_HEAD(to_free); + int i; + + /* memcg and kmem_cache debug support */ + s = slab_pre_alloc_hook(s, flags); + if (unlikely(!s)) + return false; + /* + * Drain objects in the per cpu slab, while disabling local + * IRQs, which protects against PREEMPT and interrupts + * handlers invoking normal fastpath. + */ + local_irq_disable(); + c = this_cpu_ptr(s->cpu_slab); + + for (i = 0; i < size; i++) { + void *object = c->freelist; + + if (unlikely(!object)) { + /* + * Invoking slow path likely have side-effect + * of re-populating per CPU c->freelist + */ + p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE, + _RET_IP_, c, &to_free); + if (unlikely(!p[i])) + goto error; + + c = this_cpu_ptr(s->cpu_slab); + continue; /* goto for-loop */ + } + c->freelist = get_freepointer(s, object); + p[i] = object; + } + c->tid = next_tid(c->tid); + local_irq_enable(); + free_delayed(&to_free); + + /* Clear memory outside IRQ disabled fastpath loop */ + if (unlikely(flags & __GFP_ZERO)) { + int j; + + for (j = 0; j < i; j++) + memset(p[j], 0, s->object_size); + } + + /* memcg and kmem_cache debug support */ + slab_post_alloc_hook(s, flags, size, p); + return i; +error: + local_irq_enable(); + slab_post_alloc_hook(s, flags, i, p); + __kmem_cache_free_bulk(s, i, p); + return 0; +} +EXPORT_SYMBOL(kmem_cache_alloc_bulk); + + /* * Object placement in a slab is made very easy because we always start at * offset 0. If we tune the size of the object to the alignment then we can @@ -2858,20 +3091,15 @@ static inline int slab_order(int size, int min_objects, if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE) return get_order(size * MAX_OBJS_PER_PAGE) - 1; - for (order = max(min_order, - fls(min_objects * size - 1) - PAGE_SHIFT); + for (order = max(min_order, get_order(min_objects * size + reserved)); order <= max_order; order++) { unsigned long slab_size = PAGE_SIZE << order; - if (slab_size < min_objects * size + reserved) - continue; - rem = (slab_size - reserved) % size; if (rem <= slab_size / fract_leftover) break; - } return order; @@ -2889,7 +3117,7 @@ static inline int calculate_order(int size, int reserved) * works by first attempting to generate a layout with * the best configuration and backing off gradually. * - * First we reduce the acceptable waste in a slab. Then + * First we increase the acceptable waste in a slab. Then * we reduce the minimum objects required in a slab. */ min_objects = slub_min_objects; @@ -3465,7 +3693,7 @@ void kfree(const void *x) __free_kmem_pages(page, compound_order(page)); return; } - slab_free(page->slab_cache, page, object, _RET_IP_); + slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_); } EXPORT_SYMBOL(kfree); @@ -3756,6 +3984,7 @@ void __init kmem_cache_init(void) kmem_cache_node = bootstrap(&boot_kmem_cache_node); /* Now we can use the kmem_cache to allocate kmalloc slabs */ + setup_kmalloc_cache_index_table(); create_kmalloc_caches(0); #ifdef CONFIG_SMP @@ -5236,7 +5465,7 @@ static int sysfs_slab_add(struct kmem_cache *s) s->kobj.kset = cache_kset(s); err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name); if (err) - goto out_put_kobj; + goto out; err = sysfs_create_group(&s->kobj, &slab_attr_group); if (err) @@ -5263,8 +5492,6 @@ out: return err; out_del_kobj: kobject_del(&s->kobj); -out_put_kobj: - kobject_put(&s->kobj); goto out; } |