Commit 3f28bbe5 authored by Kairui Song's avatar Kairui Song Committed by Andrew Morton
Browse files

mm/list_lru: don't pass unnecessary key parameters 

Patch series "mm/list_lru: Split list_lru lock into per-cgroup scope".

When LOCKDEP is not enabled, lock_class_key is an empty struct that is
never used.  But the list_lru initialization function still takes a
placeholder pointer as parameter, and the compiler cannot optimize it
because the function is not static and exported.

Remove this parameter and move it inside the list_lru struct.  Only use it
when LOCKDEP is enabled.  Kernel builds with LOCKDEP will be slightly
larger, while !LOCKDEP builds without it will be slightly smaller (the
common case).

Link: https://lkml.kernel.org/r/20241104175257.60853-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20241104175257.60853-2-ryncsn@gmail.com


Signed-off-by: default avatarKairui Song <kasong@tencent.com>
Acked-by: default avatarShakeel Butt <shakeel.butt@linux.dev>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 3738290b

include/linux/list_lru.h

+15 −3
Original line number Diff line number Diff line
@@ -56,16 +56,28 @@ struct list_lru { 
	bool			memcg_aware;

	struct xarray		xa;

#endif

#ifdef CONFIG_LOCKDEP

	struct lock_class_key	*key;

#endif

};



void list_lru_destroy(struct list_lru *lru);

int __list_lru_init(struct list_lru *lru, bool memcg_aware,

		    struct lock_class_key *key, struct shrinker *shrinker);

		    struct shrinker *shrinker);



#define list_lru_init(lru)				\

	__list_lru_init((lru), false, NULL, NULL)

	__list_lru_init((lru), false, NULL)

#define list_lru_init_memcg(lru, shrinker)		\

	__list_lru_init((lru), true, NULL, shrinker)

	__list_lru_init((lru), true, shrinker)



static inline int list_lru_init_memcg_key(struct list_lru *lru, struct shrinker *shrinker,

					  struct lock_class_key *key)

{

#ifdef CONFIG_LOCKDEP

	lru->key = key;

#endif

	return list_lru_init_memcg(lru, shrinker);

}



int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru,

			 gfp_t gfp);

mm/list_lru.c

+5 −4
Original line number Diff line number Diff line
@@ -562,8 +562,7 @@ static void memcg_destroy_list_lru(struct list_lru *lru) 
}

#endif /* CONFIG_MEMCG */



int __list_lru_init(struct list_lru *lru, bool memcg_aware,

		    struct lock_class_key *key, struct shrinker *shrinker)

int __list_lru_init(struct list_lru *lru, bool memcg_aware, struct shrinker *shrinker)

{

	int i;
@@ -583,8 +582,10 @@ int __list_lru_init(struct list_lru *lru, bool memcg_aware, 


	for_each_node(i) {

		spin_lock_init(&lru->node[i].lock);

		if (key)

			lockdep_set_class(&lru->node[i].lock, key);

#ifdef CONFIG_LOCKDEP

		if (lru->key)

			lockdep_set_class(&lru->node[i].lock, lru->key);

#endif

		init_one_lru(&lru->node[i].lru);

	}

mm/workingset.c

+2 −2
Original line number Diff line number Diff line
@@ -813,8 +813,8 @@ static int __init workingset_init(void) 
	if (!workingset_shadow_shrinker)

		goto err;



	ret = __list_lru_init(&shadow_nodes, true, &shadow_nodes_key,

			      workingset_shadow_shrinker);

	ret = list_lru_init_memcg_key(&shadow_nodes, workingset_shadow_shrinker,

				      &shadow_nodes_key);

	if (ret)

		goto err_list_lru;