mm: memcontrol: rename memcg_cache_id to memcg_kmem_id

The memcg_cache_id() introduced by commit 2633d7a0 ("slab/slub:
consider a memcg parameter in kmem_create_cache") is used to index in the
kmem_cache->memcg_params->memcg_caches array.  Since
kmem_cache->memcg_params.memcg_caches has been removed by commit
9855609b ("mm: memcg/slab: use a single set of kmem_caches for all
accounted allocations").  So the name does not need to reflect cache
related.  Just rename it to memcg_kmem_id.  And it can reflect kmem
related.

Link: https://lkml.kernel.org/r/20220228122126.37293-17-songmuchun@bytedance.comSigned-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/memcontrol.h

@@ -1708,7 +1708,7 @@ static inline void memcg_kmem_uncharge_page(struct page *page, int order)
  * A helper for accessing memcg's kmem_id, used for getting
  * corresponding LRU lists.
  */
-static inline int memcg_cache_id(struct mem_cgroup *memcg)
+static inline int memcg_kmem_id(struct mem_cgroup *memcg)
 {
 	return memcg ? memcg->kmemcg_id : -1;
 }
@@ -1746,7 +1746,7 @@ static inline bool memcg_kmem_enabled(void)
 	return false;
 }
 
-static inline int memcg_cache_id(struct mem_cgroup *memcg)
+static inline int memcg_kmem_id(struct mem_cgroup *memcg)
 {
 	return -1;
 }

mm/list_lru.c

@@ -75,7 +75,7 @@ list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr,
 	if (!memcg)
 		goto out;
 
-	l = list_lru_from_memcg_idx(lru, nid, memcg_cache_id(memcg));
+	l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg));
 out:
 	if (memcg_ptr)
 		*memcg_ptr = memcg;
@@ -182,7 +182,7 @@ unsigned long list_lru_count_one(struct list_lru *lru,
 	long count;
 
 	rcu_read_lock();
-	l = list_lru_from_memcg_idx(lru, nid, memcg_cache_id(memcg));
+	l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg));
 	count = l ? READ_ONCE(l->nr_items) : 0;
 	rcu_read_unlock();
 
@@ -273,7 +273,7 @@ list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
 	unsigned long ret;
 
 	spin_lock(&nlru->lock);
-	ret = __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), isolate,
+	ret = __list_lru_walk_one(lru, nid, memcg_kmem_id(memcg), isolate,
 				  cb_arg, nr_to_walk);
 	spin_unlock(&nlru->lock);
 	return ret;
@@ -289,7 +289,7 @@ list_lru_walk_one_irq(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
 	unsigned long ret;
 
 	spin_lock_irq(&nlru->lock);
-	ret = __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), isolate,
+	ret = __list_lru_walk_one(lru, nid, memcg_kmem_id(memcg), isolate,
 				  cb_arg, nr_to_walk);
 	spin_unlock_irq(&nlru->lock);
 	return ret;