diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 3 | ||||
| -rw-r--r-- | lib/debugobjects.c | 127 |
2 files changed, 115 insertions, 15 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 4219208..0b7351b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -617,6 +617,9 @@ and is between 256 and 4096 characters. It is defined in the file debug_objects [KNL] Enable object debugging + no_debug_objects + [KNL] Disable object debugging + debugpat [X86] Enable PAT debugging decnet.addr= [HW,NET] diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 5d99be1..2755a3b 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -30,7 +30,7 @@ struct debug_bucket { static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE]; -static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE]; +static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata; static DEFINE_SPINLOCK(pool_lock); @@ -50,12 +50,23 @@ static int debug_objects_enabled __read_mostly static struct debug_obj_descr *descr_test __read_mostly; +static void free_obj_work(struct work_struct *work); +static DECLARE_WORK(debug_obj_work, free_obj_work); + static int __init enable_object_debug(char *str) { debug_objects_enabled = 1; return 0; } + +static int __init disable_object_debug(char *str) +{ + debug_objects_enabled = 0; + return 0; +} + early_param("debug_objects", enable_object_debug); +early_param("no_debug_objects", disable_object_debug); static const char *obj_states[ODEBUG_STATE_MAX] = { [ODEBUG_STATE_NONE] = "none", @@ -146,25 +157,51 @@ alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr) } /* - * Put the object back into the pool or give it back to kmem_cache: + * workqueue function to free objects. */ -static void free_object(struct debug_obj *obj) +static void free_obj_work(struct work_struct *work) { - unsigned long idx = (unsigned long)(obj - obj_static_pool); + struct debug_obj *obj; unsigned long flags; - if (obj_pool_free < ODEBUG_POOL_SIZE || idx < ODEBUG_POOL_SIZE) { - spin_lock_irqsave(&pool_lock, flags); - hlist_add_head(&obj->node, &obj_pool); - obj_pool_free++; - obj_pool_used--; - spin_unlock_irqrestore(&pool_lock, flags); - } else { - spin_lock_irqsave(&pool_lock, flags); - obj_pool_used--; + spin_lock_irqsave(&pool_lock, flags); + while (obj_pool_free > ODEBUG_POOL_SIZE) { + obj = hlist_entry(obj_pool.first, typeof(*obj), node); + hlist_del(&obj->node); + obj_pool_free--; + /* + * We release pool_lock across kmem_cache_free() to + * avoid contention on pool_lock. + */ spin_unlock_irqrestore(&pool_lock, flags); kmem_cache_free(obj_cache, obj); + spin_lock_irqsave(&pool_lock, flags); } + spin_unlock_irqrestore(&pool_lock, flags); +} + +/* + * Put the object back into the pool and schedule work to free objects + * if necessary. + */ +static void free_object(struct debug_obj *obj) +{ + unsigned long flags; + int sched = 0; + + spin_lock_irqsave(&pool_lock, flags); + /* + * schedule work when the pool is filled and the cache is + * initialized: + */ + if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache) + sched = !work_pending(&debug_obj_work); + hlist_add_head(&obj->node, &obj_pool); + obj_pool_free++; + obj_pool_used--; + spin_unlock_irqrestore(&pool_lock, flags); + if (sched) + schedule_work(&debug_obj_work); } /* @@ -876,6 +913,63 @@ void __init debug_objects_early_init(void) } /* + * Convert the statically allocated objects to dynamic ones: + */ +static int debug_objects_replace_static_objects(void) +{ + struct debug_bucket *db = obj_hash; + struct hlist_node *node, *tmp; + struct debug_obj *obj, *new; + HLIST_HEAD(objects); + int i, cnt = 0; + + for (i = 0; i < ODEBUG_POOL_SIZE; i++) { + obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL); + if (!obj) + goto free; + hlist_add_head(&obj->node, &objects); + } + + /* + * When debug_objects_mem_init() is called we know that only + * one CPU is up, so disabling interrupts is enough + * protection. This avoids the lockdep hell of lock ordering. + */ + local_irq_disable(); + + /* Remove the statically allocated objects from the pool */ + hlist_for_each_entry_safe(obj, node, tmp, &obj_pool, node) + hlist_del(&obj->node); + /* Move the allocated objects to the pool */ + hlist_move_list(&objects, &obj_pool); + + /* Replace the active object references */ + for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) { + hlist_move_list(&db->list, &objects); + + hlist_for_each_entry(obj, node, &objects, node) { + new = hlist_entry(obj_pool.first, typeof(*obj), node); + hlist_del(&new->node); + /* copy object data */ + *new = *obj; + hlist_add_head(&new->node, &db->list); + cnt++; + } + } + + printk(KERN_DEBUG "ODEBUG: %d of %d active objects replaced\n", cnt, + obj_pool_used); + local_irq_enable(); + return 0; +free: + hlist_for_each_entry_safe(obj, node, tmp, &objects, node) { + hlist_del(&obj->node); + kmem_cache_free(obj_cache, obj); + } + return -ENOMEM; +} + +/* * Called after the kmem_caches are functional to setup a dedicated * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag * prevents that the debug code is called on kmem_cache_free() for the @@ -890,8 +984,11 @@ void __init debug_objects_mem_init(void) sizeof (struct debug_obj), 0, SLAB_DEBUG_OBJECTS, NULL); - if (!obj_cache) + if (!obj_cache || debug_objects_replace_static_objects()) { debug_objects_enabled = 0; - else + if (obj_cache) + kmem_cache_destroy(obj_cache); + printk(KERN_WARNING "ODEBUG: out of memory.\n"); + } else debug_objects_selftest(); } |
