mm/memcg: relocate mod_objcg_mlstate(), get_obj_stock() and put_obj_stock()

All the calls to mod_objcg_mlstate(), get_obj_stock() and
put_obj_stock() are done by functions defined within the same "#ifdef
CONFIG_MEMCG_KMEM" compilation block.  When CONFIG_MEMCG_KMEM isn't
defined, the following compilation warnings will be issued [1] and [2].

  mm/memcontrol.c:785:20: warning: unused function 'mod_objcg_mlstate'
  mm/memcontrol.c:2113:33: warning: unused function 'get_obj_stock'

Fix these warning by moving those functions to under the same
CONFIG_MEMCG_KMEM compilation block.  There is no functional change.

[1] https://lore.kernel.org/lkml/202111272014.WOYNLUV6-lkp@intel.com/
[2] https://lore.kernel.org/lkml/202111280551.LXsWYt1T-lkp@intel.com/

Link: https://lkml.kernel.org/r/20211129161140.306488-1-longman@redhat.com
Fixes: 559271146efc ("mm/memcg: optimize user context object stock access")
Fixes: 68ac5b3c8db2 ("mm/memcg: cache vmstat data in percpu memcg_stock_pcp")
Signed-off-by: Waiman Long <longman@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6863a83..2ed5f2a 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -776,24 +776,6 @@ void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val)
        rcu_read_unlock();
 }
 
-/*
- * mod_objcg_mlstate() may be called with irq enabled, so
- * mod_memcg_lruvec_state() should be used.
- */
-static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,
-                                    struct pglist_data *pgdat,
-                                    enum node_stat_item idx, int nr)
-{
-       struct mem_cgroup *memcg;
-       struct lruvec *lruvec;
-
-       rcu_read_lock();
-       memcg = obj_cgroup_memcg(objcg);
-       lruvec = mem_cgroup_lruvec(memcg, pgdat);
-       mod_memcg_lruvec_state(lruvec, idx, nr);
-       rcu_read_unlock();
-}
-
 /**
  * __count_memcg_events - account VM events in a cgroup
  * @memcg: the memory cgroup
@@ -2137,41 +2119,6 @@ static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
 }
 #endif
 
-/*
- * Most kmem_cache_alloc() calls are from user context. The irq disable/enable
- * sequence used in this case to access content from object stock is slow.
- * To optimize for user context access, there are now two object stocks for
- * task context and interrupt context access respectively.
- *
- * The task context object stock can be accessed by disabling preemption only
- * which is cheap in non-preempt kernel. The interrupt context object stock
- * can only be accessed after disabling interrupt. User context code can
- * access interrupt object stock, but not vice versa.
- */
-static inline struct obj_stock *get_obj_stock(unsigned long *pflags)
-{
-       struct memcg_stock_pcp *stock;
-
-       if (likely(in_task())) {
-               *pflags = 0UL;
-               preempt_disable();
-               stock = this_cpu_ptr(&memcg_stock);
-               return &stock->task_obj;
-       }
-
-       local_irq_save(*pflags);
-       stock = this_cpu_ptr(&memcg_stock);
-       return &stock->irq_obj;
-}
-
-static inline void put_obj_stock(unsigned long flags)
-{
-       if (likely(in_task()))
-               preempt_enable();
-       else
-               local_irq_restore(flags);
-}
-
 /**
  * consume_stock: Try to consume stocked charge on this cpu.
  * @memcg: memcg to consume from.
@@ -2816,6 +2763,59 @@ retry:
  */
 #define OBJCGS_CLEAR_MASK      (__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT)
 
+/*
+ * Most kmem_cache_alloc() calls are from user context. The irq disable/enable
+ * sequence used in this case to access content from object stock is slow.
+ * To optimize for user context access, there are now two object stocks for
+ * task context and interrupt context access respectively.
+ *
+ * The task context object stock can be accessed by disabling preemption only
+ * which is cheap in non-preempt kernel. The interrupt context object stock
+ * can only be accessed after disabling interrupt. User context code can
+ * access interrupt object stock, but not vice versa.
+ */
+static inline struct obj_stock *get_obj_stock(unsigned long *pflags)
+{
+       struct memcg_stock_pcp *stock;
+
+       if (likely(in_task())) {
+               *pflags = 0UL;
+               preempt_disable();
+               stock = this_cpu_ptr(&memcg_stock);
+               return &stock->task_obj;
+       }
+
+       local_irq_save(*pflags);
+       stock = this_cpu_ptr(&memcg_stock);
+       return &stock->irq_obj;
+}
+
+static inline void put_obj_stock(unsigned long flags)
+{
+       if (likely(in_task()))
+               preempt_enable();
+       else
+               local_irq_restore(flags);
+}
+
+/*
+ * mod_objcg_mlstate() may be called with irq enabled, so
+ * mod_memcg_lruvec_state() should be used.
+ */
+static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,
+                                    struct pglist_data *pgdat,
+                                    enum node_stat_item idx, int nr)
+{
+       struct mem_cgroup *memcg;
+       struct lruvec *lruvec;
+
+       rcu_read_lock();
+       memcg = obj_cgroup_memcg(objcg);
+       lruvec = mem_cgroup_lruvec(memcg, pgdat);
+       mod_memcg_lruvec_state(lruvec, idx, nr);
+       rcu_read_unlock();
+}
+
 int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
                                 gfp_t gfp, bool new_page)
 {