diff options
Diffstat (limited to 'mm/slab.c')
| -rw-r--r-- | mm/slab.c | 771 |
1 files changed, 470 insertions, 301 deletions
diff --git a/mm/slab.c b/mm/slab.c index 17e2848979c5..c11bf5007952 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -213,6 +213,11 @@ static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list); static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp); static void cache_reap(struct work_struct *unused); +static inline void fixup_objfreelist_debug(struct kmem_cache *cachep, + void **list); +static inline void fixup_slab_list(struct kmem_cache *cachep, + struct kmem_cache_node *n, struct page *page, + void **list); static int slab_early_init = 1; #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node)) @@ -421,8 +426,6 @@ static struct kmem_cache kmem_cache_boot = { .name = "kmem_cache", }; -#define BAD_ALIEN_MAGIC 0x01020304ul - static DEFINE_PER_CPU(struct delayed_work, slab_reap_work); static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep) @@ -519,22 +522,15 @@ static DEFINE_PER_CPU(unsigned long, slab_reap_node); static void init_reap_node(int cpu) { - int node; - - node = next_node(cpu_to_mem(cpu), node_online_map); - if (node == MAX_NUMNODES) - node = first_node(node_online_map); - - per_cpu(slab_reap_node, cpu) = node; + per_cpu(slab_reap_node, cpu) = next_node_in(cpu_to_mem(cpu), + node_online_map); } static void next_reap_node(void) { int node = __this_cpu_read(slab_reap_node); - node = next_node(node, node_online_map); - if (unlikely(node >= MAX_NUMNODES)) - node = first_node(node_online_map); + node = next_node_in(node, node_online_map); __this_cpu_write(slab_reap_node, node); } @@ -644,7 +640,7 @@ static int transfer_objects(struct array_cache *to, static inline struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp) { - return (struct alien_cache **)BAD_ALIEN_MAGIC; + return NULL; } static inline void free_alien_cache(struct alien_cache **ac_ptr) @@ -850,6 +846,46 @@ static inline gfp_t gfp_exact_node(gfp_t flags) } #endif +static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp) +{ + struct kmem_cache_node *n; + + /* + * Set up the kmem_cache_node for cpu before we can + * begin anything. Make sure some other cpu on this + * node has not already allocated this + */ + n = get_node(cachep, node); + if (n) { + spin_lock_irq(&n->list_lock); + n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount + + cachep->num; + spin_unlock_irq(&n->list_lock); + + return 0; + } + + n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node); + if (!n) + return -ENOMEM; + + kmem_cache_node_init(n); + n->next_reap = jiffies + REAPTIMEOUT_NODE + + ((unsigned long)cachep) % REAPTIMEOUT_NODE; + + n->free_limit = + (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num; + + /* + * The kmem_cache_nodes don't come and go as CPUs + * come and go. slab_mutex is sufficient + * protection here. + */ + cachep->node[node] = n; + + return 0; +} + /* * Allocates and initializes node for a node on each slab cache, used for * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node @@ -861,46 +897,82 @@ static inline gfp_t gfp_exact_node(gfp_t flags) */ static int init_cache_node_node(int node) { + int ret; struct kmem_cache *cachep; - struct kmem_cache_node *n; - const size_t memsize = sizeof(struct kmem_cache_node); list_for_each_entry(cachep, &slab_caches, list) { - /* - * Set up the kmem_cache_node for cpu before we can - * begin anything. Make sure some other cpu on this - * node has not already allocated this - */ - n = get_node(cachep, node); - if (!n) { - n = kmalloc_node(memsize, GFP_KERNEL, node); - if (!n) - return -ENOMEM; - kmem_cache_node_init(n); - n->next_reap = jiffies + REAPTIMEOUT_NODE + - ((unsigned long)cachep) % REAPTIMEOUT_NODE; - - /* - * The kmem_cache_nodes don't come and go as CPUs - * come and go. slab_mutex is sufficient - * protection here. - */ - cachep->node[node] = n; - } - - spin_lock_irq(&n->list_lock); - n->free_limit = - (1 + nr_cpus_node(node)) * - cachep->batchcount + cachep->num; - spin_unlock_irq(&n->list_lock); + ret = init_cache_node(cachep, node, GFP_KERNEL); + if (ret) + return ret; } + return 0; } -static inline int slabs_tofree(struct kmem_cache *cachep, - struct kmem_cache_node *n) +static int setup_kmem_cache_node(struct kmem_cache *cachep, + int node, gfp_t gfp, bool force_change) { - return (n->free_objects + cachep->num - 1) / cachep->num; + int ret = -ENOMEM; + struct kmem_cache_node *n; + struct array_cache *old_shared = NULL; + struct array_cache *new_shared = NULL; + struct alien_cache **new_alien = NULL; + LIST_HEAD(list); + + if (use_alien_caches) { + new_alien = alloc_alien_cache(node, cachep->limit, gfp); + if (!new_alien) + goto fail; + } + + if (cachep->shared) { + new_shared = alloc_arraycache(node, + cachep->shared * cachep->batchcount, 0xbaadf00d, gfp); + if (!new_shared) + goto fail; + } + + ret = init_cache_node(cachep, node, gfp); + if (ret) + goto fail; + + n = get_node(cachep, node); + spin_lock_irq(&n->list_lock); + if (n->shared && force_change) { + free_block(cachep, n->shared->entry, + n->shared->avail, node, &list); + n->shared->avail = 0; + } + + if (!n->shared || force_change) { + old_shared = n->shared; + n->shared = new_shared; + new_shared = NULL; + } + + if (!n->alien) { + n->alien = new_alien; + new_alien = NULL; + } + + spin_unlock_irq(&n->list_lock); + slabs_destroy(cachep, &list); + + /* + * To protect lockless access to n->shared during irq disabled context. + * If n->shared isn't NULL in irq disabled context, accessing to it is + * guaranteed to be valid until irq is re-enabled, because it will be + * freed after synchronize_sched(). + */ + if (force_change) + synchronize_sched(); + +fail: + kfree(old_shared); + kfree(new_shared); + free_alien_cache(new_alien); + + return ret; } static void cpuup_canceled(long cpu) @@ -967,14 +1039,13 @@ free_slab: n = get_node(cachep, node); if (!n) continue; - drain_freelist(cachep, n, slabs_tofree(cachep, n)); + drain_freelist(cachep, n, INT_MAX); } } static int cpuup_prepare(long cpu) { struct kmem_cache *cachep; - struct kmem_cache_node *n = NULL; int node = cpu_to_mem(cpu); int err; @@ -993,44 +1064,9 @@ static int cpuup_prepare(long cpu) * array caches */ list_for_each_entry(cachep, &slab_caches, list) { - struct array_cache *shared = NULL; - struct alien_cache **alien = NULL; - - if (cachep->shared) { - shared = alloc_arraycache(node, - cachep->shared * cachep->batchcount, - 0xbaadf00d, GFP_KERNEL); - if (!shared) - goto bad; - } - if (use_alien_caches) { - alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL); - if (!alien) { - kfree(shared); - goto bad; - } - } - n = get_node(cachep, node); - BUG_ON(!n); - - spin_lock_irq(&n->list_lock); - if (!n->shared) { - /* - * We are serialised from CPU_DEAD or - * CPU_UP_CANCELLED by the cpucontrol lock - */ - n->shared = shared; - shared = NULL; - } -#ifdef CONFIG_NUMA - if (!n->alien) { - n->alien = alien; - alien = NULL; - } -#endif - spin_unlock_irq(&n->list_lock); - kfree(shared); - free_alien_cache(alien); + err = setup_kmem_cache_node(cachep, node, GFP_KERNEL, false); + if (err) + goto bad; } return 0; @@ -1119,7 +1155,7 @@ static int __meminit drain_cache_node_node(int node) if (!n) continue; - drain_freelist(cachep, n, slabs_tofree(cachep, n)); + drain_freelist(cachep, n, INT_MAX); if (!list_empty(&n->slabs_full) || !list_empty(&n->slabs_partial)) { @@ -1200,6 +1236,61 @@ static void __init set_up_node(struct kmem_cache *cachep, int index) } } +#ifdef CONFIG_SLAB_FREELIST_RANDOM +static void freelist_randomize(struct rnd_state *state, freelist_idx_t *list, + size_t count) +{ + size_t i; + unsigned int rand; + + for (i = 0; i < count; i++) + list[i] = i; + + /* Fisher-Yates shuffle */ + for (i = count - 1; i > 0; i--) { + rand = prandom_u32_state(state); + rand %= (i + 1); + swap(list[i], list[rand]); + } +} + +/* Create a random sequence per cache */ +static int cache_random_seq_create(struct kmem_cache *cachep, gfp_t gfp) +{ + unsigned int seed, count = cachep->num; + struct rnd_state state; + + if (count < 2) + return 0; + + /* If it fails, we will just use the global lists */ + cachep->random_seq = kcalloc(count, sizeof(freelist_idx_t), gfp); + if (!cachep->random_seq) + return -ENOMEM; + + /* Get best entropy at this stage */ + get_random_bytes_arch(&seed, sizeof(seed)); + prandom_seed_state(&state, seed); + + freelist_randomize(&state, cachep->random_seq, count); + return 0; +} + +/* Destroy the per-cache random freelist sequence */ +static void cache_random_seq_destroy(struct kmem_cache *cachep) +{ + kfree(cachep->random_seq); + cachep->random_seq = NULL; +} +#else +static inline int cache_random_seq_create(struct kmem_cache *cachep, gfp_t gfp) +{ + return 0; +} +static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { } +#endif /* CONFIG_SLAB_FREELIST_RANDOM */ + + /* * Initialisation. Called after the page allocator have been initialised and * before smp_init(). @@ -1212,7 +1303,7 @@ void __init kmem_cache_init(void) sizeof(struct rcu_head)); kmem_cache = &kmem_cache_boot; - if (num_possible_nodes() == 1) + if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1) use_alien_caches = 0; for (i = 0; i < NUM_INIT_LISTS; i++) @@ -1781,7 +1872,7 @@ static size_t calculate_slab_order(struct kmem_cache *cachep, /* * Needed to avoid possible looping condition - * in cache_grow() + * in cache_grow_begin() */ if (OFF_SLAB(freelist_cache)) continue; @@ -2138,7 +2229,7 @@ done: cachep->freelist_size = cachep->num * sizeof(freelist_idx_t); cachep->flags = flags; cachep->allocflags = __GFP_COMP; - if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA)) + if (flags & SLAB_CACHE_DMA) cachep->allocflags |= GFP_DMA; cachep->size = size; cachep->reciprocal_buffer_size = reciprocal_value(size); @@ -2180,6 +2271,11 @@ static void check_irq_on(void) BUG_ON(irqs_disabled()); } +static void check_mutex_acquired(void) +{ + BUG_ON(!mutex_is_locked(&slab_mutex)); +} + static void check_spinlock_acquired(struct kmem_cache *cachep) { #ifdef CONFIG_SMP @@ -2199,13 +2295,27 @@ static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node) #else #define check_irq_off() do { } while(0) #define check_irq_on() do { } while(0) +#define check_mutex_acquired() do { } while(0) #define check_spinlock_acquired(x) do { } while(0) #define check_spinlock_acquired_node(x, y) do { } while(0) #endif -static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n, - struct array_cache *ac, - int force, int node); +static void drain_array_locked(struct kmem_cache *cachep, struct array_cache *ac, + int node, bool free_all, struct list_head *list) +{ + int tofree; + + if (!ac || !ac->avail) + return; + + tofree = free_all ? ac->avail : (ac->limit + 4) / 5; + if (tofree > ac->avail) + tofree = (ac->avail + 1) / 2; + + free_block(cachep, ac->entry, tofree, node, list); + ac->avail -= tofree; + memmove(ac->entry, &(ac->entry[tofree]), sizeof(void *) * ac->avail); +} static void do_drain(void *arg) { @@ -2229,6 +2339,7 @@ static void drain_cpu_caches(struct kmem_cache *cachep) { struct kmem_cache_node *n; int node; + LIST_HEAD(list); on_each_cpu(do_drain, cachep, 1); check_irq_on(); @@ -2236,8 +2347,13 @@ static void drain_cpu_caches(struct kmem_cache *cachep) if (n->alien) drain_alien_cache(cachep, n->alien); - for_each_kmem_cache_node(cachep, node, n) - drain_array(cachep, n, n->shared, 1, node); + for_each_kmem_cache_node(cachep, node, n) { + spin_lock_irq(&n->list_lock); + drain_array_locked(cachep, n->shared, node, true, &list); + spin_unlock_irq(&n->list_lock); + + slabs_destroy(cachep, &list); + } } /* @@ -2288,7 +2404,7 @@ int __kmem_cache_shrink(struct kmem_cache *cachep, bool deactivate) check_irq_on(); for_each_kmem_cache_node(cachep, node, n) { - drain_freelist(cachep, n, slabs_tofree(cachep, n)); + drain_freelist(cachep, n, INT_MAX); ret += !list_empty(&n->slabs_full) || !list_empty(&n->slabs_partial); @@ -2306,6 +2422,8 @@ void __kmem_cache_release(struct kmem_cache *cachep) int i; struct kmem_cache_node *n; + cache_random_seq_destroy(cachep); + free_percpu(cachep->cpu_cache); /* NUMA: free the node structures */ @@ -2412,15 +2530,115 @@ static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page) #endif } +#ifdef CONFIG_SLAB_FREELIST_RANDOM +/* Hold information during a freelist initialization */ +union freelist_init_state { + struct { + unsigned int pos; + freelist_idx_t *list; + unsigned int count; + unsigned int rand; + }; + struct rnd_state rnd_state; +}; + +/* + * Initialize the state based on the randomization methode available. + * return true if the pre-computed list is available, false otherwize. + */ +static bool freelist_state_initialize(union freelist_init_state *state, + struct kmem_cache *cachep, + unsigned int count) +{ + bool ret; + unsigned int rand; + + /* Use best entropy available to define a random shift */ + get_random_bytes_arch(&rand, sizeof(rand)); + + /* Use a random state if the pre-computed list is not available */ + if (!cachep->random_seq) { + prandom_seed_state(&state->rnd_state, rand); + ret = false; + } else { + state->list = cachep->random_seq; + state->count = count; + state->pos = 0; + state->rand = rand; + ret = true; + } + return ret; +} + +/* Get the next entry on the list and randomize it using a random shift */ +static freelist_idx_t next_random_slot(union freelist_init_state *state) +{ + return (state->list[state->pos++] + state->rand) % state->count; +} + +/* + * Shuffle the freelist initialization state based on pre-computed lists. + * return true if the list was successfully shuffled, false otherwise. + */ +static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page) +{ + unsigned int objfreelist = 0, i, count = cachep->num; + union freelist_init_state state; + bool precomputed; + + if (count < 2) + return false; + + precomputed = freelist_state_initialize(&state, cachep, count); + + /* Take a random entry as the objfreelist */ + if (OBJFREELIST_SLAB(cachep)) { + if (!precomputed) + objfreelist = count - 1; + else + objfreelist = next_random_slot(&state); + page->freelist = index_to_obj(cachep, page, objfreelist) + + obj_offset(cachep); + count--; + } + + /* + * On early boot, generate the list dynamically. + * Later use a pre-computed list for speed. + */ + if (!precomputed) { + freelist_randomize(&state.rnd_state, page->freelist, count); + } else { + for (i = 0; i < count; i++) + set_free_obj(page, i, next_random_slot(&state)); + } + + if (OBJFREELIST_SLAB(cachep)) + set_free_obj(page, cachep->num - 1, objfreelist); + + return true; +} +#else +static inline bool shuffle_freelist(struct kmem_cache *cachep, + struct page *page) +{ + return false; +} +#endif /* CONFIG_SLAB_FREELIST_RANDOM */ + static void cache_init_objs(struct kmem_cache *cachep, struct page *page) { int i; void *objp; + bool shuffled; cache_init_objs_debug(cachep, page); - if (OBJFREELIST_SLAB(cachep)) { + /* Try to randomize the freelist if enabled */ + shuffled = shuffle_freelist(cachep, page); + + if (!shuffled && OBJFREELIST_SLAB(cachep)) { page->freelist = index_to_obj(cachep, page, cachep->num - 1) + obj_offset(cachep); } @@ -2434,17 +2652,8 @@ static void cache_init_objs(struct kmem_cache *cachep, kasan_poison_object_data(cachep, objp); } - set_free_obj(page, i, i); - } -} - -static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags) -{ - if (CONFIG_ZONE_DMA_FLAG) { - if (flags & GFP_DMA) - BUG_ON(!(cachep->allocflags & GFP_DMA)); - else - BUG_ON(cachep->allocflags & GFP_DMA); + if (!shuffled) + set_free_obj(page, i, i); } } @@ -2502,13 +2711,15 @@ static void slab_map_pages(struct kmem_cache *cache, struct page *page, * Grow (by 1) the number of slabs within a cache. This is called by * 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, struct page *page) +static struct page *cache_grow_begin(struct kmem_cache *cachep, + gfp_t flags, int nodeid) { void *freelist; size_t offset; gfp_t local_flags; + int page_node; struct kmem_cache_node *n; + struct page *page; /* * Be lazy and only check for valid flags here, keeping it out of the @@ -2520,43 +2731,35 @@ static int cache_grow(struct kmem_cache *cachep, } local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); - /* Take the node list lock to change the colour_next on this node */ check_irq_off(); - n = get_node(cachep, nodeid); - spin_lock(&n->list_lock); - - /* Get colour for the slab, and cal the next value. */ - offset = n->colour_next; - n->colour_next++; - if (n->colour_next >= cachep->colour) - n->colour_next = 0; - spin_unlock(&n->list_lock); - - offset *= cachep->colour_off; - if (gfpflags_allow_blocking(local_flags)) local_irq_enable(); /* - * The test for missing atomic flag is performed here, rather than - * the more obvious place, simply to reduce the critical path length - * in kmem_cache_alloc(). If a caller is seriously mis-behaving they - * will eventually be caught here (where it matters). - */ - kmem_flagcheck(cachep, flags); - - /* * Get mem for the objs. Attempt to allocate a physical page from * 'nodeid'. */ - if (!page) - page = kmem_getpages(cachep, local_flags, nodeid); + page = kmem_getpages(cachep, local_flags, nodeid); if (!page) goto failed; + page_node = page_to_nid(page); + n = get_node(cachep, page_node); + + /* Get colour for the slab, and cal the next value. */ + n->colour_next++; + if (n->colour_next >= cachep->colour) + n->colour_next = 0; + + offset = n->colour_next; + if (offset >= cachep->colour) + offset = 0; + + offset *= cachep->colour_off; + /* Get slab management. */ freelist = alloc_slabmgmt(cachep, page, offset, - local_flags & ~GFP_CONSTRAINT_MASK, nodeid); + local_flags & ~GFP_CONSTRAINT_MASK, page_node); if (OFF_SLAB(cachep) && !freelist) goto opps1; @@ -2567,21 +2770,40 @@ static int cache_grow(struct kmem_cache *cachep, if (gfpflags_allow_blocking(local_flags)) local_irq_disable(); - check_irq_off(); - spin_lock(&n->list_lock); - /* Make slab active. */ - list_add_tail(&page->lru, &(n->slabs_free)); - STATS_INC_GROWN(cachep); - n->free_objects += cachep->num; - spin_unlock(&n->list_lock); - return 1; + return page; + opps1: kmem_freepages(cachep, page); failed: if (gfpflags_allow_blocking(local_flags)) local_irq_disable(); - return 0; + return NULL; +} + +static void cache_grow_end(struct kmem_cache *cachep, struct page *page) +{ + struct kmem_cache_node *n; + void *list = NULL; + + check_irq_off(); + + if (!page) + return; + + INIT_LIST_HEAD(&page->lru); + n = get_node(cachep, page_to_nid(page)); + + spin_lock(&n->list_lock); + if (!page->active) + list_add_tail(&page->lru, &(n->slabs_free)); + else + fixup_slab_list(cachep, n, page, &list); + STATS_INC_GROWN(cachep); + n->free_objects += cachep->num - page->active; + spin_unlock(&n->list_lock); + + fixup_objfreelist_debug(cachep, &list); } #if DEBUG @@ -2785,18 +3007,42 @@ static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep, return obj; } +/* + * Slab list should be fixed up by fixup_slab_list() for existing slab + * or cache_grow_end() for new slab + */ +static __always_inline int alloc_block(struct kmem_cache *cachep, + struct array_cache *ac, struct page *page, int batchcount) +{ + /* + * There must be at least one object available for + * allocation. + */ + BUG_ON(page->active >= cachep->num); + + while (page->active < cachep->num && batchcount--) { + STATS_INC_ALLOCED(cachep); + STATS_INC_ACTIVE(cachep); + STATS_SET_HIGH(cachep); + + ac->entry[ac->avail++] = slab_get_obj(cachep, page); + } + + return batchcount; +} + static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) { int batchcount; struct kmem_cache_node *n; - struct array_cache *ac; + struct array_cache *ac, *shared; int node; void *list = NULL; + struct page *page; check_irq_off(); node = numa_mem_id(); -retry: ac = cpu_cache_get(cachep); batchcount = ac->batchcount; if (!ac->touched && batchcount > BATCHREFILL_LIMIT) { @@ -2810,16 +3056,20 @@ retry: n = get_node(cachep, node); BUG_ON(ac->avail > 0 || !n); + shared = READ_ONCE(n->shared); + if (!n->free_objects && (!shared || !shared->avail)) + goto direct_grow; + spin_lock(&n->list_lock); + shared = READ_ONCE(n->shared); /* See if we can refill from the shared array */ - if (n->shared && transfer_objects(ac, n->shared, batchcount)) { - n->shared->touched = 1; + if (shared && transfer_objects(ac, shared, batchcount)) { + shared->touched = 1; goto alloc_done; } while (batchcount > 0) { - struct page *page; /* Get slab alloc is to come from. */ page = get_first_slab(n, false); if (!page) @@ -2827,21 +3077,7 @@ retry: check_spinlock_acquired(cachep); - /* - * The slab was either on partial or free list so - * there must be at least one object available for - * allocation. - */ - BUG_ON(page->active >= cachep->num); - - while (page->active < cachep->num && batchcount--) { - STATS_INC_ALLOCED(cachep); - STATS_INC_ACTIVE(cachep); - STATS_SET_HIGH(cachep); - - ac->entry[ac->avail++] = slab_get_obj(cachep, page); - } - + batchcount = alloc_block(cachep, ac, page, batchcount); fixup_slab_list(cachep, n, page, &list); } @@ -2851,9 +3087,8 @@ alloc_done: spin_unlock(&n->list_lock); fixup_objfreelist_debug(cachep, &list); +direct_grow: if (unlikely(!ac->avail)) { - int x; - /* Check if we can use obj in pfmemalloc slab */ if (sk_memalloc_socks()) { void *obj = cache_alloc_pfmemalloc(cachep, n, flags); @@ -2862,18 +3097,19 @@ alloc_done: return obj; } - x = cache_grow(cachep, gfp_exact_node(flags), node, NULL); + page = cache_grow_begin(cachep, gfp_exact_node(flags), node); - /* cache_grow can reenable interrupts, then ac could change. */ + /* + * cache_grow_begin() can reenable interrupts, + * then ac could change. + */ ac = cpu_cache_get(cachep); - node = numa_mem_id(); + if (!ac->avail && page) + alloc_block(cachep, ac, page, batchcount); + cache_grow_end(cachep, page); - /* no objects in sight? abort */ - if (!x && ac->avail == 0) + if (!ac->avail) return NULL; - - if (!ac->avail) /* objects refilled by interrupt? */ - goto retry; } ac->touched = 1; @@ -2884,9 +3120,6 @@ static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep, gfp_t flags) { might_sleep_if(gfpflags_allow_blocking(flags)); -#if DEBUG - kmem_flagcheck(cachep, flags); -#endif } #if DEBUG @@ -2998,19 +3231,17 @@ static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags) static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags) { struct zonelist *zonelist; - gfp_t local_flags; struct zoneref *z; struct zone *zone; enum zone_type high_zoneidx = gfp_zone(flags); void *obj = NULL; + struct page *page; int nid; unsigned int cpuset_mems_cookie; if (flags & __GFP_THISNODE) return NULL; - local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); - retry_cpuset: cpuset_mems_cookie = read_mems_allowed_begin(); zonelist = node_zonelist(mempolicy_slab_node(), flags); @@ -3040,33 +3271,19 @@ retry: * We may trigger various forms of reclaim on the allowed * set and go into memory reserves if necessary. */ - struct page *page; - - if (gfpflags_allow_blocking(local_flags)) - local_irq_enable(); - kmem_flagcheck(cache, flags); - page = kmem_getpages(cache, local_flags, numa_mem_id()); - if (gfpflags_allow_blocking(local_flags)) - local_irq_disable(); + page = cache_grow_begin(cache, flags, numa_mem_id()); + cache_grow_end(cache, page); if (page) { + nid = page_to_nid(page); + obj = ____cache_alloc_node(cache, + gfp_exact_node(flags), nid); + /* - * Insert into the appropriate per node queues + * Another processor may allocate the objects in + * the slab since we are not holding any locks. */ - nid = page_to_nid(page); - if (cache_grow(cache, flags, nid, page)) { - obj = ____cache_alloc_node(cache, - gfp_exact_node(flags), nid); - if (!obj) - /* - * Another processor may allocate the - * objects in the slab since we are - * not holding any locks. - */ - goto retry; - } else { - /* cache_grow already freed obj */ - obj = NULL; - } + if (!obj) + goto retry; } } @@ -3083,15 +3300,13 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, { struct page *page; struct kmem_cache_node *n; - void *obj; + void *obj = NULL; void *list = NULL; - int x; VM_BUG_ON(nodeid < 0 || nodeid >= MAX_NUMNODES); n = get_node(cachep, nodeid); BUG_ON(!n); -retry: check_irq_off(); spin_lock(&n->list_lock); page = get_first_slab(n, false); @@ -3113,18 +3328,18 @@ retry: spin_unlock(&n->list_lock); fixup_objfreelist_debug(cachep, &list); - goto done; + return obj; must_grow: spin_unlock(&n->list_lock); - x = cache_grow(cachep, gfp_exact_node(flags), nodeid, NULL); - if (x) - goto retry; - - return fallback_alloc(cachep, flags); + page = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid); + if (page) { + /* This slab isn't counted yet so don't update free_objects */ + obj = slab_get_obj(cachep, page); + } + cache_grow_end(cachep, page); -done: - return obj; + return obj ? obj : fallback_alloc(cachep, flags); } static __always_inline void * @@ -3242,6 +3457,9 @@ static void free_block(struct kmem_cache *cachep, void **objpp, { int i; struct kmem_cache_node *n = get_node(cachep, node); + struct page *page; + + n->free_objects += nr_objects; for (i = 0; i < nr_objects; i++) { void *objp; @@ -3254,17 +3472,11 @@ static void free_block(struct kmem_cache *cachep, void **objpp, check_spinlock_acquired_node(cachep, node); slab_put_obj(cachep, page, objp); STATS_DEC_ACTIVE(cachep); - n->free_objects++; /* fixup slab chains */ - if (page->active == 0) { - if (n->free_objects > n->free_limit) { - n->free_objects -= cachep->num; - list_add_tail(&page->lru, list); - } else { - list_add(&page->lru, &n->slabs_free); - } - } else { + if (page->active == 0) + 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. @@ -3272,6 +3484,14 @@ static void free_block(struct kmem_cache *cachep, void **objpp, list_add_tail(&page->lru, &n->slabs_partial); } } + + while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) { + n->free_objects -= cachep->num; + + page = list_last_entry(&n->slabs_free, struct page, lru); + list_del(&page->lru); + list_add(&page->lru, list); + } } static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) @@ -3645,72 +3865,19 @@ EXPORT_SYMBOL(kfree); /* * This initializes kmem_cache_node or resizes various caches for all nodes. */ -static int alloc_kmem_cache_node(struct kmem_cache *cachep, gfp_t gfp) +static int setup_kmem_cache_nodes(struct kmem_cache *cachep, gfp_t gfp) { + int ret; int node; struct kmem_cache_node *n; - struct array_cache *new_shared; - struct alien_cache **new_alien = NULL; for_each_online_node(node) { - - if (use_alien_caches) { - new_alien = alloc_alien_cache(node, cachep->limit, gfp); - if (!new_alien) - goto fail; - } - - new_shared = NULL; - if (cachep->shared) { - new_shared = alloc_arraycache(node, - cachep->shared*cachep->batchcount, - 0xbaadf00d, gfp); - if (!new_shared) { - free_alien_cache(new_alien); - goto fail; - } - } - - n = get_node(cachep, node); - if (n) { - struct array_cache *shared = n->shared; - LIST_HEAD(list); - - spin_lock_irq(&n->list_lock); - - if (shared) - free_block(cachep, shared->entry, - shared->avail, node, &list); - - n->shared = new_shared; - if (!n->alien) { - n->alien = new_alien; - new_alien = NULL; - } - n->free_limit = (1 + nr_cpus_node(node)) * - cachep->batchcount + cachep->num; - spin_unlock_irq(&n->list_lock); - slabs_destroy(cachep, &list); - kfree(shared); - free_alien_cache(new_alien); - continue; - } - n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node); - if (!n) { - free_alien_cache(new_alien); - kfree(new_shared); + ret = setup_kmem_cache_node(cachep, node, gfp, true); + if (ret) goto fail; - } - kmem_cache_node_init(n); - n->next_reap = jiffies + REAPTIMEOUT_NODE + - ((unsigned long)cachep) % REAPTIMEOUT_NODE; - n->shared = new_shared; - n->alien = new_alien; - n->free_limit = (1 + nr_cpus_node(node)) * - cachep->batchcount + cachep->num; - cachep->node[node] = n; } + return 0; fail: @@ -3752,7 +3919,7 @@ static int __do_tune_cpucache(struct kmem_cache *cachep, int limit, cachep->shared = shared; if (!prev) - goto alloc_node; + goto setup_node; for_each_online_cpu(cpu) { LIST_HEAD(list); @@ -3769,8 +3936,8 @@ static int __do_tune_cpucache(struct kmem_cache *cachep, int limit, } free_percpu(prev); -alloc_node: - return alloc_kmem_cache_node(cachep, gfp); +setup_node: + return setup_kmem_cache_nodes(cachep, gfp); } static int do_tune_cpucache(struct kmem_cache *cachep, int limit, @@ -3804,6 +3971,10 @@ static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) int shared = 0; int batchcount = 0; + err = cache_random_seq_create(cachep, gfp); + if (err) + goto end; + if (!is_root_cache(cachep)) { struct kmem_cache *root = memcg_root_cache(cachep); limit = root->limit; @@ -3857,6 +4028,7 @@ static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) batchcount = (limit + 1) / 2; skip_setup: err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp); +end: if (err) pr_err("enable_cpucache failed for %s, error %d\n", cachep->name, -err); @@ -3869,29 +4041,26 @@ skip_setup: * if drain_array() is used on the shared array. */ static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n, - struct array_cache *ac, int force, int node) + struct array_cache *ac, int node) { LIST_HEAD(list); - int tofree; + + /* ac from n->shared can be freed if we don't hold the slab_mutex. */ + check_mutex_acquired(); if (!ac || !ac->avail) return; - if (ac->touched && !force) { + + if (ac->touched) { ac->touched = 0; - } else { - spin_lock_irq(&n->list_lock); - if (ac->avail) { - tofree = force ? ac->avail : (ac->limit + 4) / 5; - if (tofree > ac->avail) - tofree = (ac->avail + 1) / 2; - free_block(cachep, ac->entry, tofree, node, &list); - ac->avail -= tofree; - memmove(ac->entry, &(ac->entry[tofree]), - sizeof(void *) * ac->avail); - } - spin_unlock_irq(&n->list_lock); - slabs_destroy(cachep, &list); + return; } + + spin_lock_irq(&n->list_lock); + drain_array_locked(cachep, ac, node, false, &list); + spin_unlock_irq(&n->list_lock); + + slabs_destroy(cachep, &list); } /** @@ -3929,7 +4098,7 @@ static void cache_reap(struct work_struct *w) reap_alien(searchp, n); - drain_array(searchp, n, cpu_cache_get(searchp), 0, node); + drain_array(searchp, n, cpu_cache_get(searchp), node); /* * These are racy checks but it does not matter @@ -3940,7 +4109,7 @@ static void cache_reap(struct work_struct *w) n->next_reap = jiffies + REAPTIMEOUT_NODE; - drain_array(searchp, n, n->shared, 0, node); + drain_array(searchp, n, n->shared, node); if (n->free_touched) n->free_touched = 0; |