Re: [patch 18/25] debugobjects: Use static key for boot pool selection

[Leizhen (ThunderTown)]

On 2024/10/8 0:50, Thomas Gleixner wrote:
> Get rid of the conditional in the hot path.

Reviewed-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>

> 
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
>  lib/debugobjects.c |   19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> --- a/lib/debugobjects.c
> +++ b/lib/debugobjects.c
> @@ -7,16 +7,16 @@
>  
>  #define pr_fmt(fmt) "ODEBUG: " fmt
>  
> +#include <linux/cpu.h>
>  #include <linux/debugobjects.h>
> -#include <linux/interrupt.h>
> +#include <linux/debugfs.h>
> +#include <linux/hash.h>
> +#include <linux/kmemleak.h>
>  #include <linux/sched.h>
>  #include <linux/sched/task_stack.h>
>  #include <linux/seq_file.h>
> -#include <linux/debugfs.h>
>  #include <linux/slab.h>
> -#include <linux/hash.h>
> -#include <linux/kmemleak.h>
> -#include <linux/cpu.h>
> +#include <linux/static_key.h>
>  
>  #define ODEBUG_HASH_BITS	14
>  #define ODEBUG_HASH_SIZE	(1 << ODEBUG_HASH_BITS)
> @@ -103,6 +103,8 @@ static int __data_racy		debug_objects_fr
>  static void free_obj_work(struct work_struct *work);
>  static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
>  
> +static DEFINE_STATIC_KEY_FALSE(obj_cache_enabled);
> +
>  static int __init enable_object_debug(char *str)
>  {
>  	debug_objects_enabled = true;
> @@ -343,7 +345,7 @@ static struct debug_obj *alloc_object(vo
>  {
>  	struct debug_obj *obj;
>  
> -	if (likely(obj_cache))
> +	if (static_branch_likely(&obj_cache_enabled))
>  		obj = pcpu_alloc();
>  	else
>  		obj = __alloc_object(&pool_boot);
> @@ -393,7 +395,7 @@ static void free_obj_work(struct work_st
>  static void __free_object(struct debug_obj *obj)
>  {
>  	guard(irqsave)();
> -	if (likely(obj_cache))
> +	if (static_branch_likely(&obj_cache_enabled))
>  		pcpu_free(obj);
>  	else
>  		hlist_add_head(&obj->node, &pool_boot);
> @@ -572,7 +574,7 @@ static struct debug_obj *lookup_object_o
>  
>  static void debug_objects_fill_pool(void)
>  {
> -	if (unlikely(!obj_cache))
> +	if (!static_branch_likely(&obj_cache_enabled))
>  		return;
>  
>  	if (likely(!pool_should_refill(&pool_global)))
> @@ -1378,6 +1380,7 @@ void __init debug_objects_mem_init(void)
>  
>  	/* Everything worked. Expose the cache */
>  	obj_cache = cache;
> +	static_branch_enable(&obj_cache_enabled);
>  
>  #ifdef CONFIG_HOTPLUG_CPU
>  	cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
> 
> .
> 

-- 
Regards,
  Zhen Lei