From a2a702383e8baa22ee66ee60f1e036835a1ef42e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 7 Oct 2024 18:49:57 +0200 Subject: debugobjects: Dont free objects directly on CPU hotplug Freeing the per CPU pool of the unplugged CPU directly is suboptimal as the objects can be reused in the real pool if there is room. Aside of that this gets the accounting wrong. Use the regular free path, which allows reuse and has the accounting correct. Signed-off-by: Thomas Gleixner Reviewed-by: Zhen Lei Link: https://lore.kernel.org/all/20241007164913.263960570@linutronix.de --- lib/debugobjects.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) (limited to 'lib/debugobjects.c') diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 9867412d7946..a3d4c54f0839 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -430,27 +430,28 @@ static void free_object(struct debug_obj *obj) } #ifdef CONFIG_HOTPLUG_CPU -static int object_cpu_offline(unsigned int cpu) +static void put_objects(struct hlist_head *list) { - struct debug_percpu_free *percpu_pool; struct hlist_node *tmp; struct debug_obj *obj; - unsigned long flags; - /* Remote access is safe as the CPU is dead already */ - percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu); - hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) { + /* + * Using free_object() puts the objects into reuse or schedules + * them for freeing and it get's all the accounting correct. + */ + hlist_for_each_entry_safe(obj, tmp, list, node) { hlist_del(&obj->node); - kmem_cache_free(obj_cache, obj); + free_object(obj); } +} - raw_spin_lock_irqsave(&pool_lock, flags); - obj_pool_used -= percpu_pool->obj_free; - debug_objects_freed += percpu_pool->obj_free; - raw_spin_unlock_irqrestore(&pool_lock, flags); - - percpu_pool->obj_free = 0; +static int object_cpu_offline(unsigned int cpu) +{ + /* Remote access is safe as the CPU is dead already */ + struct debug_percpu_free *pcp = per_cpu_ptr(&percpu_obj_pool, cpu); + put_objects(&pcp->free_objs); + pcp->obj_free = 0; return 0; } #endif -- cgit v1.2.3