diff options
Diffstat (limited to 'mm/slab.c')
| -rw-r--r-- | mm/slab.c | 314 |
1 files changed, 271 insertions, 43 deletions
diff --git a/mm/slab.c b/mm/slab.c index 26138c9f8f0..681837499d7 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -204,7 +204,8 @@ typedef unsigned int kmem_bufctl_t; #define BUFCTL_END (((kmem_bufctl_t)(~0U))-0) #define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1) -#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-2) +#define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2) +#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3) /* Max number of objs-per-slab for caches which use off-slab slabs. * Needed to avoid a possible looping condition in cache_grow(). @@ -897,6 +898,30 @@ static struct array_cache *alloc_arraycache(int node, int entries, return nc; } +/* + * Transfer objects in one arraycache to another. + * Locking must be handled by the caller. + * + * Return the number of entries transferred. + */ +static int transfer_objects(struct array_cache *to, + struct array_cache *from, unsigned int max) +{ + /* Figure out how many entries to transfer */ + int nr = min(min(from->avail, max), to->limit - to->avail); + + if (!nr) + return 0; + + memcpy(to->entry + to->avail, from->entry + from->avail -nr, + sizeof(void *) *nr); + + from->avail -= nr; + to->avail += nr; + to->touched = 1; + return nr; +} + #ifdef CONFIG_NUMA static void *__cache_alloc_node(struct kmem_cache *, gfp_t, int); static void *alternate_node_alloc(struct kmem_cache *, gfp_t); @@ -946,6 +971,13 @@ static void __drain_alien_cache(struct kmem_cache *cachep, if (ac->avail) { spin_lock(&rl3->list_lock); + /* + * Stuff objects into the remote nodes shared array first. + * That way we could avoid the overhead of putting the objects + * into the free lists and getting them back later. + */ + transfer_objects(rl3->shared, ac, ac->limit); + free_block(cachep, ac->entry, ac->avail, node); ac->avail = 0; spin_unlock(&rl3->list_lock); @@ -961,8 +993,8 @@ static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3) if (l3->alien) { struct array_cache *ac = l3->alien[node]; - if (ac && ac->avail) { - spin_lock_irq(&ac->lock); + + if (ac && ac->avail && spin_trylock_irq(&ac->lock)) { __drain_alien_cache(cachep, ac, node); spin_unlock_irq(&ac->lock); } @@ -1989,10 +2021,9 @@ kmem_cache_create (const char *name, size_t size, size_t align, align = ralign; /* Get cache's description obj. */ - cachep = kmem_cache_alloc(&cache_cache, SLAB_KERNEL); + cachep = kmem_cache_zalloc(&cache_cache, SLAB_KERNEL); if (!cachep) goto oops; - memset(cachep, 0, sizeof(struct kmem_cache)); #if DEBUG cachep->obj_size = size; @@ -2399,7 +2430,7 @@ static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp, /* Verify that the slab belongs to the intended node */ WARN_ON(slabp->nodeid != nodeid); - if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) { + 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(); @@ -2605,6 +2636,9 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, */ cachep->dtor(objp + obj_offset(cachep), cachep, 0); } +#ifdef CONFIG_DEBUG_SLAB_LEAK + slab_bufctl(slabp)[objnr] = BUFCTL_FREE; +#endif if (cachep->flags & SLAB_POISON) { #ifdef CONFIG_DEBUG_PAGEALLOC if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) { @@ -2677,20 +2711,10 @@ retry: BUG_ON(ac->avail > 0 || !l3); spin_lock(&l3->list_lock); - if (l3->shared) { - struct array_cache *shared_array = l3->shared; - if (shared_array->avail) { - if (batchcount > shared_array->avail) - batchcount = shared_array->avail; - shared_array->avail -= batchcount; - ac->avail = batchcount; - memcpy(ac->entry, - &(shared_array->entry[shared_array->avail]), - sizeof(void *) * batchcount); - shared_array->touched = 1; - goto alloc_done; - } - } + /* See if we can refill from the shared array */ + if (l3->shared && transfer_objects(ac, l3->shared, batchcount)) + goto alloc_done; + while (batchcount > 0) { struct list_head *entry; struct slab *slabp; @@ -2788,6 +2812,16 @@ 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 = page_get_slab(virt_to_page(objp)); + objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size; + slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE; + } +#endif objp += obj_offset(cachep); if (cachep->ctor && cachep->flags & SLAB_POISON) { unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR; @@ -3094,6 +3128,23 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) EXPORT_SYMBOL(kmem_cache_alloc); /** + * kmem_cache_alloc - Allocate an object. The memory is set to zero. + * @cache: The cache to allocate from. + * @flags: See kmalloc(). + * + * Allocate an object from this cache and set the allocated memory to zero. + * The flags are only relevant if the cache has no available objects. + */ +void *kmem_cache_zalloc(struct kmem_cache *cache, gfp_t flags) +{ + void *ret = __cache_alloc(cache, flags, __builtin_return_address(0)); + if (ret) + memset(ret, 0, obj_size(cache)); + return ret; +} +EXPORT_SYMBOL(kmem_cache_zalloc); + +/** * kmem_ptr_validate - check if an untrusted pointer might * be a slab entry. * @cachep: the cache we're checking against @@ -3220,22 +3271,23 @@ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, return __cache_alloc(cachep, flags, caller); } -#ifndef CONFIG_DEBUG_SLAB void *__kmalloc(size_t size, gfp_t flags) { +#ifndef CONFIG_DEBUG_SLAB return __do_kmalloc(size, flags, NULL); +#else + return __do_kmalloc(size, flags, __builtin_return_address(0)); +#endif } EXPORT_SYMBOL(__kmalloc); -#else - +#ifdef CONFIG_DEBUG_SLAB void *__kmalloc_track_caller(size_t size, gfp_t flags, void *caller) { return __do_kmalloc(size, flags, caller); } EXPORT_SYMBOL(__kmalloc_track_caller); - #endif #ifdef CONFIG_SMP @@ -3366,63 +3418,86 @@ const char *kmem_cache_name(struct kmem_cache *cachep) EXPORT_SYMBOL_GPL(kmem_cache_name); /* - * This initializes kmem_list3 for all nodes. + * This initializes kmem_list3 or resizes varioius caches for all nodes. */ static int alloc_kmemlist(struct kmem_cache *cachep) { int node; struct kmem_list3 *l3; - int err = 0; + struct array_cache *new_shared; + struct array_cache **new_alien; for_each_online_node(node) { - struct array_cache *nc = NULL, *new; - struct array_cache **new_alien = NULL; -#ifdef CONFIG_NUMA + new_alien = alloc_alien_cache(node, cachep->limit); if (!new_alien) goto fail; -#endif - new = alloc_arraycache(node, cachep->shared*cachep->batchcount, + + new_shared = alloc_arraycache(node, + cachep->shared*cachep->batchcount, 0xbaadf00d); - if (!new) + if (!new_shared) { + free_alien_cache(new_alien); goto fail; + } + l3 = cachep->nodelists[node]; if (l3) { + struct array_cache *shared = l3->shared; + spin_lock_irq(&l3->list_lock); - nc = cachep->nodelists[node]->shared; - if (nc) - free_block(cachep, nc->entry, nc->avail, node); + if (shared) + free_block(cachep, shared->entry, + shared->avail, node); - l3->shared = new; - if (!cachep->nodelists[node]->alien) { + l3->shared = new_shared; + if (!l3->alien) { l3->alien = new_alien; new_alien = NULL; } l3->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num; spin_unlock_irq(&l3->list_lock); - kfree(nc); + kfree(shared); free_alien_cache(new_alien); continue; } l3 = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, node); - if (!l3) + if (!l3) { + free_alien_cache(new_alien); + kfree(new_shared); goto fail; + } kmem_list3_init(l3); l3->next_reap = jiffies + REAPTIMEOUT_LIST3 + ((unsigned long)cachep) % REAPTIMEOUT_LIST3; - l3->shared = new; + l3->shared = new_shared; l3->alien = new_alien; l3->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num; cachep->nodelists[node] = l3; } - return err; + return 0; + fail: - err = -ENOMEM; - return err; + if (!cachep->next.next) { + /* Cache is not active yet. Roll back what we did */ + node--; + while (node >= 0) { + if (cachep->nodelists[node]) { + l3 = cachep->nodelists[node]; + + kfree(l3->shared); + free_alien_cache(l3->alien); + kfree(l3); + cachep->nodelists[node] = NULL; + } + node--; + } + } + return -ENOMEM; } struct ccupdate_struct { @@ -3899,6 +3974,159 @@ ssize_t slabinfo_write(struct file *file, const char __user * buffer, res = count; return res; } + +#ifdef CONFIG_DEBUG_SLAB_LEAK + +static void *leaks_start(struct seq_file *m, loff_t *pos) +{ + loff_t n = *pos; + struct list_head *p; + + mutex_lock(&cache_chain_mutex); + p = cache_chain.next; + while (n--) { + p = p->next; + if (p == &cache_chain) + return NULL; + } + return list_entry(p, struct kmem_cache, next); +} + +static inline int add_caller(unsigned long *n, unsigned long v) +{ + unsigned long *p; + int l; + if (!v) + return 1; + l = n[1]; + p = n + 2; + while (l) { + int i = l/2; + unsigned long *q = p + 2 * i; + if (*q == v) { + q[1]++; + return 1; + } + if (*q > v) { + l = i; + } else { + p = q + 2; + l -= i + 1; + } + } + if (++n[1] == n[0]) + return 0; + memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n)); + p[0] = v; + p[1] = 1; + return 1; +} + +static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s) +{ + void *p; + int i; + if (n[0] == n[1]) + return; + for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) { + if (slab_bufctl(s)[i] != BUFCTL_ACTIVE) + continue; + if (!add_caller(n, (unsigned long)*dbg_userword(c, p))) + return; + } +} + +static void show_symbol(struct seq_file *m, unsigned long address) +{ +#ifdef CONFIG_KALLSYMS + char *modname; + const char *name; + unsigned long offset, size; + char namebuf[KSYM_NAME_LEN+1]; + + name = kallsyms_lookup(address, &size, &offset, &modname, namebuf); + + if (name) { + seq_printf(m, "%s+%#lx/%#lx", name, offset, size); + if (modname) + seq_printf(m, " [%s]", modname); + return; + } +#endif + seq_printf(m, "%p", (void *)address); +} + +static int leaks_show(struct seq_file *m, void *p) +{ + struct kmem_cache *cachep = p; + struct list_head *q; + struct slab *slabp; + struct kmem_list3 *l3; + const char *name; + unsigned long *n = m->private; + int node; + int i; + + if (!(cachep->flags & SLAB_STORE_USER)) + return 0; + if (!(cachep->flags & SLAB_RED_ZONE)) + return 0; + + /* OK, we can do it */ + + n[1] = 0; + + for_each_online_node(node) { + l3 = cachep->nodelists[node]; + if (!l3) + continue; + + check_irq_on(); + spin_lock_irq(&l3->list_lock); + + list_for_each(q, &l3->slabs_full) { + slabp = list_entry(q, struct slab, list); + handle_slab(n, cachep, slabp); + } + list_for_each(q, &l3->slabs_partial) { + slabp = list_entry(q, struct slab, list); + handle_slab(n, cachep, slabp); + } + spin_unlock_irq(&l3->list_lock); + } + name = cachep->name; + if (n[0] == n[1]) { + /* Increase the buffer size */ + mutex_unlock(&cache_chain_mutex); + m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL); + if (!m->private) { + /* Too bad, we are really out */ + m->private = n; + mutex_lock(&cache_chain_mutex); + return -ENOMEM; + } + *(unsigned long *)m->private = n[0] * 2; + kfree(n); + mutex_lock(&cache_chain_mutex); + /* Now make sure this entry will be retried */ + m->count = m->size; + return 0; + } + for (i = 0; i < n[1]; i++) { + seq_printf(m, "%s: %lu ", name, n[2*i+3]); + show_symbol(m, n[2*i+2]); + seq_putc(m, '\n'); + } + return 0; +} + +struct seq_operations slabstats_op = { + .start = leaks_start, + .next = s_next, + .stop = s_stop, + .show = leaks_show, +}; +#endif #endif /** |