Commit 5412b539 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'core/debugobjects' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core/debugobjects' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  debugobjects: delay free of internal objects
  debugobjects: replace static objects when slab cache becomes available
  debug_objects: add boot-parameter toggle to turn object debugging off again
parents e4c393fd 337fff8b
......@@ -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]
......
......@@ -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_obj_work(struct work_struct *work)
{
struct debug_obj *obj;
unsigned long flags;
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 idx = (unsigned long)(obj - obj_static_pool);
unsigned long flags;
int sched = 0;
if (obj_pool_free < ODEBUG_POOL_SIZE || idx < ODEBUG_POOL_SIZE) {
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);
} else {
spin_lock_irqsave(&pool_lock, flags);
obj_pool_used--;
spin_unlock_irqrestore(&pool_lock, flags);
kmem_cache_free(obj_cache, obj);
}
if (sched)
schedule_work(&debug_obj_work);
}
/*
......@@ -875,6 +912,63 @@ void __init debug_objects_early_init(void)
hlist_add_head(&obj_static_pool[i].node, &obj_pool);
}
/*
* 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
......@@ -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();
}
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