debugobjects: Use separate list head for boot pool

There is no point to handle the statically allocated objects during early
boot in the actual pool list. This phase does not require accounting, so
all of the related complexity can be avoided.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/all/20241007164913.708939081@linutronix.de

Author: KAGA-KOKO

lib/debugobjects.c

@@ -68,6 +68,8 @@ static DEFINE_RAW_SPINLOCK(pool_lock);
 static struct obj_pool		pool_global;
 static struct obj_pool		pool_to_free;
 
+static HLIST_HEAD(pool_boot);
+
 /*
  * Because of the presence of percpu free pools, obj_pool_free will
  * under-count those in the percpu free pools. Similarly, obj_pool_used
@@ -278,6 +280,9 @@ alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *d
 			percpu_pool->obj_free--;
 			goto init_obj;
 		}
+	} else {
+		obj = __alloc_object(&pool_boot);
+		goto init_obj;
 	}
 
 	raw_spin_lock(&pool_lock);
@@ -381,12 +386,14 @@ static void __free_object(struct debug_obj *obj)
 	struct debug_obj *objs[ODEBUG_BATCH_SIZE];
 	struct debug_percpu_free *percpu_pool;
 	int lookahead_count = 0;
-	unsigned long flags;
 	bool work;
 
-	local_irq_save(flags);
-	if (!obj_cache)
-		goto free_to_obj_pool;
+	guard(irqsave)();
+
+	if (unlikely(!obj_cache)) {
+		hlist_add_head(&obj->node, &pool_boot);
+		return;
+	}
 
 	/*
 	 * Try to free it into the percpu pool first.
@@ -395,7 +402,6 @@ static void __free_object(struct debug_obj *obj)
 	if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
 		hlist_add_head(&obj->node, &percpu_pool->free_objs);
 		percpu_pool->obj_free++;
-		local_irq_restore(flags);
 		return;
 	}
 
@@ -410,7 +416,6 @@ static void __free_object(struct debug_obj *obj)
 		percpu_pool->obj_free--;
 	}
 
-free_to_obj_pool:
 	raw_spin_lock(&pool_lock);
 	work = (pool_global.cnt > debug_objects_pool_size) && obj_cache &&
 	       (pool_to_free.cnt < ODEBUG_FREE_WORK_MAX);
@@ -455,7 +460,6 @@ static void __free_object(struct debug_obj *obj)
 		}
 	}
 	raw_spin_unlock(&pool_lock);
-	local_irq_restore(flags);
 }
 
 /*
@@ -1341,10 +1345,9 @@ void __init debug_objects_early_init(void)
 	for (i = 0; i < ODEBUG_HASH_SIZE; i++)
 		raw_spin_lock_init(&obj_hash[i].lock);
 
+	/* Keep early boot simple and add everything to the boot list */
 	for (i = 0; i < ODEBUG_POOL_SIZE; i++)
-		hlist_add_head(&obj_static_pool[i].node, &pool_global.objects);
-
-	pool_global.cnt = ODEBUG_POOL_SIZE;
+		hlist_add_head(&obj_static_pool[i].node, &pool_boot);
 }
 
 /*
@@ -1372,10 +1375,11 @@ static bool __init debug_objects_replace_static_objects(struct kmem_cache *cache
 	pool_global.cnt = ODEBUG_POOL_SIZE;
 
 	/*
-	 * Replace the statically allocated objects list with the allocated
-	 * objects list.
+	 * Move the allocated objects to the global pool and disconnect the
+	 * boot pool.
 	 */
 	hlist_move_list(&objects, &pool_global.objects);
+	pool_boot.first = NULL;
 
 	/* Replace the active object references */
 	for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {