[PATCH v2 1/5] mm/memcg: Pass both memcg and lruvec to mod_memcg_lruvec_state()

[Waiman Long]

The caller of mod_memcg_lruvec_state() has both memcg and lruvec readily
available. So both of them are now passed to mod_memcg_lruvec_state()
and __mod_memcg_lruvec_state(). The __mod_memcg_lruvec_state() is
updated to allow either of the two parameters to be set to null. This
makes mod_memcg_lruvec_state() equivalent to mod_memcg_state() if lruvec
is null.

The new __mod_memcg_lruvec_state() function will be used in the next
patch as a replacement of mod_memcg_state() in mm/percpu.c for the
consolidation of the memory uncharge and vmstat update functions in
the kmem_cache_free() path.

Signed-off-by: Waiman Long <long...@redhat.com>
Acked-by: Roman Gushchin <g...@fb.com>
Reviewed-by: Shakeel Butt <shake...@google.com>
---
 include/linux/memcontrol.h | 12 +++++++-----
 mm/memcontrol.c            | 19 +++++++++++++------
 mm/slab.h                  |  2 +-
 3 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 0c04d39a7967..95f12996e66c 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -955,8 +955,8 @@ static inline unsigned long lruvec_page_state_local(struct 
lruvec *lruvec,
        return x;
 }
 
-void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
-                             int val);
+void __mod_memcg_lruvec_state(struct mem_cgroup *memcg, struct lruvec *lruvec,
+                             enum node_stat_item idx, int val);
 void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val);
 
 static inline void mod_lruvec_kmem_state(void *p, enum node_stat_item idx,
@@ -969,13 +969,14 @@ static inline void mod_lruvec_kmem_state(void *p, enum 
node_stat_item idx,
        local_irq_restore(flags);
 }
 
-static inline void mod_memcg_lruvec_state(struct lruvec *lruvec,
+static inline void mod_memcg_lruvec_state(struct mem_cgroup *memcg,
+                                         struct lruvec *lruvec,
                                          enum node_stat_item idx, int val)
 {
        unsigned long flags;
 
        local_irq_save(flags);
-       __mod_memcg_lruvec_state(lruvec, idx, val);
+       __mod_memcg_lruvec_state(memcg, lruvec, idx, val);
        local_irq_restore(flags);
 }
 
@@ -1369,7 +1370,8 @@ static inline unsigned long 
lruvec_page_state_local(struct lruvec *lruvec,
        return node_page_state(lruvec_pgdat(lruvec), idx);
 }
 
-static inline void __mod_memcg_lruvec_state(struct lruvec *lruvec,
+static inline void __mod_memcg_lruvec_state(struct mem_cgroup *memcg,
+                                           struct lruvec *lruvec,
                                            enum node_stat_item idx, int val)
 {
 }
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e064ac0d850a..d66e1e38f8ac 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -799,20 +799,27 @@ parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid)
        return mem_cgroup_nodeinfo(parent, nid);
 }
 
-void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
-                             int val)
+/*
+ * Either one of memcg or lruvec can be NULL, but not both.
+ */
+void __mod_memcg_lruvec_state(struct mem_cgroup *memcg, struct lruvec *lruvec,
+                             enum node_stat_item idx, int val)
 {
        struct mem_cgroup_per_node *pn;
-       struct mem_cgroup *memcg;
        long x, threshold = MEMCG_CHARGE_BATCH;
 
+       /* Update lruvec */
        pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
-       memcg = pn->memcg;
+
+       if (!memcg)
+               memcg = pn->memcg;
 
        /* Update memcg */
        __mod_memcg_state(memcg, idx, val);
 
-       /* Update lruvec */
+       if (!lruvec)
+               return;
+
        __this_cpu_add(pn->lruvec_stat_local->count[idx], val);
 
        if (vmstat_item_in_bytes(idx))
@@ -848,7 +855,7 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum 
node_stat_item idx,
 
        /* Update memcg and lruvec */
        if (!mem_cgroup_disabled())
-               __mod_memcg_lruvec_state(lruvec, idx, val);
+               __mod_memcg_lruvec_state(NULL, lruvec, idx, val);
 }
 
 void __mod_lruvec_page_state(struct page *page, enum node_stat_item idx,
diff --git a/mm/slab.h b/mm/slab.h
index 076582f58f68..bc6c7545e487 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -293,7 +293,7 @@ static inline void mod_objcg_state(struct obj_cgroup *objcg,
        rcu_read_lock();
        memcg = obj_cgroup_memcg(objcg);
        lruvec = mem_cgroup_lruvec(memcg, pgdat);
-       mod_memcg_lruvec_state(lruvec, idx, nr);
+       mod_memcg_lruvec_state(memcg, lruvec, idx, nr);
        rcu_read_unlock();
 }
 
-- 
2.18.1