net: tcp_memcontrol: simplify linkage between socket and page counter

There won't be any separate counters for socket memory consumed by
protocols other than TCP in the future.  Remove the indirection and link
sockets directly to their owning memory cgroup.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 35 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f5de783860b8..eaaa86126277 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -294,9 +294,6 @@ static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
 void sock_update_memcg(struct sock *sk)
 {
         struct mem_cgroup *memcg;
-        struct cg_proto *cg_proto;
-
-        BUG_ON(!sk->sk_prot->proto_cgroup);
 
         /* Socket cloning can throw us here with sk_cgrp already
          * filled. It won't however, necessarily happen from
@@ -306,68 +303,58 @@ void sock_update_memcg(struct sock *sk)
          * Respecting the original socket's memcg is a better
          * decision in this case.
          */
-        if (sk->sk_cgrp) {
-                BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
-                css_get(&sk->sk_cgrp->memcg->css);
+        if (sk->sk_memcg) {
+                BUG_ON(mem_cgroup_is_root(sk->sk_memcg));
+                css_get(&sk->sk_memcg->css);
                 return;
         }
 
         rcu_read_lock();
         memcg = mem_cgroup_from_task(current);
-        cg_proto = sk->sk_prot->proto_cgroup(memcg);
-        if (cg_proto && cg_proto->active &&
-            css_tryget_online(&memcg->css)) {
-                sk->sk_cgrp = cg_proto;
-        }
+        if (memcg != root_mem_cgroup &&
+            memcg->tcp_mem.active &&
+            css_tryget_online(&memcg->css))
+                sk->sk_memcg = memcg;
         rcu_read_unlock();
 }
 EXPORT_SYMBOL(sock_update_memcg);
 
 void sock_release_memcg(struct sock *sk)
 {
-        WARN_ON(!sk->sk_cgrp->memcg);
-        css_put(&sk->sk_cgrp->memcg->css);
-}
-
-struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
-{
-        if (!memcg || mem_cgroup_is_root(memcg))
-                return NULL;
-
-        return &memcg->tcp_mem;
+        WARN_ON(!sk->sk_memcg);
+        css_put(&sk->sk_memcg->css);
 }
-EXPORT_SYMBOL(tcp_proto_cgroup);
 
 /**
  * mem_cgroup_charge_skmem - charge socket memory
- * @proto: proto to charge
+ * @memcg: memcg to charge
  * @nr_pages: number of pages to charge
  *
- * Charges @nr_pages to @proto. Returns %true if the charge fit within
- * @proto's configured limit, %false if the charge had to be forced.
+ * Charges @nr_pages to @memcg. Returns %true if the charge fit within
+ * @memcg's configured limit, %false if the charge had to be forced.
  */
-bool mem_cgroup_charge_skmem(struct cg_proto *proto, unsigned int nr_pages)
+bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
 {
         struct page_counter *counter;
 
-        if (page_counter_try_charge(&proto->memory_allocated,
+        if (page_counter_try_charge(&memcg->tcp_mem.memory_allocated,
                                     nr_pages, &counter)) {
-                proto->memory_pressure = 0;
+                memcg->tcp_mem.memory_pressure = 0;
                 return true;
         }
-        page_counter_charge(&proto->memory_allocated, nr_pages);
-        proto->memory_pressure = 1;
+        page_counter_charge(&memcg->tcp_mem.memory_allocated, nr_pages);
+        memcg->tcp_mem.memory_pressure = 1;
         return false;
 }
 
 /**
  * mem_cgroup_uncharge_skmem - uncharge socket memory
- * @proto - proto to uncharge
+ * @memcg - memcg to uncharge
  * @nr_pages - number of pages to uncharge
  */
-void mem_cgroup_uncharge_skmem(struct cg_proto *proto, unsigned int nr_pages)
+void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
 {
-        page_counter_uncharge(&proto->memory_allocated, nr_pages);
+        page_counter_uncharge(&memcg->tcp_mem.memory_allocated, nr_pages);
 }
 
 #endif
@@ -3653,7 +3640,7 @@ static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
         if (ret)
                 return ret;
 
-        return mem_cgroup_sockets_init(memcg, ss);
+        return tcp_init_cgroup(memcg, ss);
 }
 
 static void memcg_deactivate_kmem(struct mem_cgroup *memcg)
@@ -3709,7 +3696,7 @@ static void memcg_destroy_kmem(struct mem_cgroup *memcg)
                 static_key_slow_dec(&memcg_kmem_enabled_key);
                 WARN_ON(page_counter_read(&memcg->kmem));
         }
-        mem_cgroup_sockets_destroy(memcg);
+        tcp_destroy_cgroup(memcg);
 }
 #else
 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)