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authorLinus Torvalds <torvalds@linux-foundation.org>2009-04-05 10:26:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-05 10:26:36 -0700
commit5412b5399e095730008a14f2107331b2123733e4 (patch)
tree6b3a7aee35a2d7d97cef33a077e6c60a394f5298
parentMerge branch 'printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip (diff)
parentdebugobjects: delay free of internal objects (diff)
downloadlinux-dev-5412b5399e095730008a14f2107331b2123733e4.tar.xz
linux-dev-5412b5399e095730008a14f2107331b2123733e4.zip
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
-rw-r--r--Documentation/kernel-parameters.txt3
-rw-r--r--lib/debugobjects.c127
2 files changed, 115 insertions, 15 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 421920897a37..0b7351b0582c 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 5d99be1fd988..2755a3bd16a1 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();
}