mm: memcontrol: implement lruvec stat functions on top of each other

The implementation of the lruvec stat functions and their variants for
accounting through a page, or accounting from a preemptible context, are
mostly identical and needlessly repetitive.

Implement the lruvec_page functions by looking up the page's lruvec and
then using the lruvec function.

Implement the functions for preemptible contexts by disabling preemption
before calling the atomic context functions.

Link: http://lkml.kernel.org/r/20171103153336.24044-2-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 22 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 2c80b69dd266..1ffc54ac4cc9 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -569,51 +569,51 @@ static inline void __mod_lruvec_state(struct lruvec *lruvec,
 {
         struct mem_cgroup_per_node *pn;
 
+        /* Update node */
         __mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
+
         if (mem_cgroup_disabled())
                 return;
+
         pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
+
+        /* Update memcg */
         __mod_memcg_state(pn->memcg, idx, val);
+
+        /* Update lruvec */
         __this_cpu_add(pn->lruvec_stat->count[idx], val);
 }
 
 static inline void mod_lruvec_state(struct lruvec *lruvec,
                                     enum node_stat_item idx, int val)
 {
-        struct mem_cgroup_per_node *pn;
-
-        mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
-        if (mem_cgroup_disabled())
-                return;
-        pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
-        mod_memcg_state(pn->memcg, idx, val);
-        this_cpu_add(pn->lruvec_stat->count[idx], val);
+        preempt_disable();
+        __mod_lruvec_state(lruvec, idx, val);
+        preempt_enable();
 }
 
 static inline void __mod_lruvec_page_state(struct page *page,
                                            enum node_stat_item idx, int val)
 {
-        struct mem_cgroup_per_node *pn;
+        pg_data_t *pgdat = page_pgdat(page);
+        struct lruvec *lruvec;
 
-        __mod_node_page_state(page_pgdat(page), idx, val);
-        if (mem_cgroup_disabled() || !page->mem_cgroup)
+        /* Untracked pages have no memcg, no lruvec. Update only the node */
+        if (!page->mem_cgroup) {
+                __mod_node_page_state(pgdat, idx, val);
                 return;
-        __mod_memcg_state(page->mem_cgroup, idx, val);
-        pn = page->mem_cgroup->nodeinfo[page_to_nid(page)];
-        __this_cpu_add(pn->lruvec_stat->count[idx], val);
+        }
+
+        lruvec = mem_cgroup_lruvec(pgdat, page->mem_cgroup);
+        __mod_lruvec_state(lruvec, idx, val);
 }
 
 static inline void mod_lruvec_page_state(struct page *page,
                                          enum node_stat_item idx, int val)
 {
-        struct mem_cgroup_per_node *pn;
-
-        mod_node_page_state(page_pgdat(page), idx, val);
-        if (mem_cgroup_disabled() || !page->mem_cgroup)
-                return;
-        mod_memcg_state(page->mem_cgroup, idx, val);
-        pn = page->mem_cgroup->nodeinfo[page_to_nid(page)];
-        this_cpu_add(pn->lruvec_stat->count[idx], val);
+        preempt_disable();
+        __mod_lruvec_page_state(page, idx, val);
+        preempt_enable();
 }
 
 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,