mm: memcontrol: flatten struct cg_proto

There are no more external users of struct cg_proto, flatten the
structure into struct mem_cgroup.

Since using those struct members doesn't stand out as much anymore,
add cgroup2 static branches to make it clearer which code is legacy.

Suggested-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 21 insertions, 26 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 47995b499429..a3869bf97746 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -85,12 +85,6 @@ enum mem_cgroup_events_target {
         MEM_CGROUP_NTARGETS,
 };
 
-struct cg_proto {
-        struct page_counter     memory_allocated;       /* Current allocated memory. */
-        int                     memory_pressure;
-        bool                    active;
-};
-
 #ifdef CONFIG_MEMCG
 struct mem_cgroup_stat_cpu {
         long count[MEM_CGROUP_STAT_NSTATS];
@@ -169,8 +163,11 @@ struct mem_cgroup {
 
         /* Accounted resources */
         struct page_counter memory;
+
+        /* Legacy consumer-oriented counters */
         struct page_counter memsw;
         struct page_counter kmem;
+        struct page_counter tcpmem;
 
         /* Normal memory consumption range */
         unsigned long low;
@@ -236,7 +233,8 @@ struct mem_cgroup {
         unsigned long           socket_pressure;
 
         /* Legacy tcp memory accounting */
-        struct cg_proto tcp_mem;
+        bool                    tcpmem_active;
+        int                     tcpmem_pressure;
 
 #ifndef CONFIG_SLOB
         /* Index in the kmem_cache->memcg_params.memcg_caches array */
@@ -715,7 +713,7 @@ extern struct static_key_false memcg_sockets_enabled_key;
 #define mem_cgroup_sockets_enabled static_branch_unlikely(&memcg_sockets_enabled_key)
 static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
 {
-        if (memcg->tcp_mem.memory_pressure)
+        if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_pressure)
                 return true;
         do {
                 if (time_before(jiffies, memcg->socket_pressure))
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 379f9911b87b..6937f16f5ecb 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2843,7 +2843,7 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
                 counter = &memcg->kmem;
                 break;
         case _TCP:
-                counter = &memcg->tcp_mem.memory_allocated;
+                counter = &memcg->tcpmem;
                 break;
         default:
                 BUG();
@@ -3028,11 +3028,11 @@ static int memcg_update_tcp_limit(struct mem_cgroup *memcg, unsigned long limit)
 
         mutex_lock(&memcg_limit_mutex);
 
-        ret = page_counter_limit(&memcg->tcp_mem.memory_allocated, limit);
+        ret = page_counter_limit(&memcg->tcpmem, limit);
         if (ret)
                 goto out;
 
-        if (!memcg->tcp_mem.active) {
+        if (!memcg->tcpmem_active) {
                 /*
                  * The active flag needs to be written after the static_key
                  * update. This is what guarantees that the socket activation
@@ -3050,7 +3050,7 @@ static int memcg_update_tcp_limit(struct mem_cgroup *memcg, unsigned long limit)
                  * patched in yet.
                  */
                 static_branch_inc(&memcg_sockets_enabled_key);
-                memcg->tcp_mem.active = true;
+                memcg->tcpmem_active = true;
         }
 out:
         mutex_unlock(&memcg_limit_mutex);
@@ -3119,7 +3119,7 @@ static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
                 counter = &memcg->kmem;
                 break;
         case _TCP:
-                counter = &memcg->tcp_mem.memory_allocated;
+                counter = &memcg->tcpmem;
                 break;
         default:
                 BUG();
@@ -4295,8 +4295,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)
                 memcg->soft_limit = PAGE_COUNTER_MAX;
                 page_counter_init(&memcg->memsw, &parent->memsw);
                 page_counter_init(&memcg->kmem, &parent->kmem);
-                page_counter_init(&memcg->tcp_mem.memory_allocated,
-                                  &parent->tcp_mem.memory_allocated);
+                page_counter_init(&memcg->tcpmem, &parent->tcpmem);
 
                 /*
                  * No need to take a reference to the parent because cgroup
@@ -4308,7 +4307,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)
                 memcg->soft_limit = PAGE_COUNTER_MAX;
                 page_counter_init(&memcg->memsw, NULL);
                 page_counter_init(&memcg->kmem, NULL);
-                page_counter_init(&memcg->tcp_mem.memory_allocated, NULL);
+                page_counter_init(&memcg->tcpmem, NULL);
                 /*
                  * Deeper hierachy with use_hierarchy == false doesn't make
                  * much sense so let cgroup subsystem know about this
@@ -4374,7 +4373,7 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
         if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
                 static_branch_dec(&memcg_sockets_enabled_key);
 
-        if (memcg->tcp_mem.active)
+        if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
                 static_branch_dec(&memcg_sockets_enabled_key);
 
         memcg_free_kmem(memcg);
@@ -5601,7 +5600,7 @@ void sock_update_memcg(struct sock *sk)
         memcg = mem_cgroup_from_task(current);
         if (memcg == root_mem_cgroup)
                 goto out;
-        if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcp_mem.active)
+        if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
                 goto out;
         if (css_tryget_online(&memcg->css))
                 sk->sk_memcg = memcg;
@@ -5629,15 +5628,14 @@ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
         gfp_t gfp_mask = GFP_KERNEL;
 
         if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
-                struct page_counter *counter;
+                struct page_counter *fail;
 
-                if (page_counter_try_charge(&memcg->tcp_mem.memory_allocated,
-                                            nr_pages, &counter)) {
-                        memcg->tcp_mem.memory_pressure = 0;
+                if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
+                        memcg->tcpmem_pressure = 0;
                         return true;
                 }
-                page_counter_charge(&memcg->tcp_mem.memory_allocated, nr_pages);
-                memcg->tcp_mem.memory_pressure = 1;
+                page_counter_charge(&memcg->tcpmem, nr_pages);
+                memcg->tcpmem_pressure = 1;
                 return false;
         }
 
@@ -5660,8 +5658,7 @@ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
 {
         if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
-                page_counter_uncharge(&memcg->tcp_mem.memory_allocated,
-                                      nr_pages);
+                page_counter_uncharge(&memcg->tcpmem, nr_pages);
                 return;
         }