memcg: remove some redundant checks

We don't need to check do_swap_account in the case that the function which
checks do_swap_account will never get called if do_swap_account == 0.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 4 insertions, 15 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6f682901deb5..3468c38adde6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -45,7 +45,7 @@ struct cgroup_subsys mem_cgroup_subsys __read_mostly;
 #define MEM_CGROUP_RECLAIM_RETRIES      5
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
-/* Turned on only when memory cgroup is enabled && really_do_swap_account = 0 */
+/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
 int do_swap_account __read_mostly;
 static int really_do_swap_account __initdata = 1; /* for remember boot option*/
 #else
@@ -1763,16 +1763,14 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
         return ret;
 }
 
-int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
-                                unsigned long long val)
+static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
+                                        unsigned long long val)
 {
         int retry_count;
         u64 memlimit, oldusage, curusage;
         int children = mem_cgroup_count_children(memcg);
         int ret = -EBUSY;
 
-        if (!do_swap_account)
-                return -EINVAL;
         /* see mem_cgroup_resize_res_limit */
         retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
         oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
@@ -2007,8 +2005,7 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
                 val = res_counter_read_u64(&mem->res, name);
                 break;
         case _MEMSWAP:
-                if (do_swap_account)
-                        val = res_counter_read_u64(&mem->memsw, name);
+                val = res_counter_read_u64(&mem->memsw, name);
                 break;
         default:
                 BUG();
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 672089d5819f..f22b4ebbd8dc 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -311,8 +311,6 @@ static int swap_cgroup_prepare(int type)
         struct swap_cgroup_ctrl *ctrl;
         unsigned long idx, max;
 
-        if (!do_swap_account)
-                return 0;
         ctrl = &swap_cgroup_ctrl[type];
 
         for (idx = 0; idx < ctrl->length; idx++) {
@@ -349,9 +347,6 @@ unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
         struct swap_cgroup *sc;
         unsigned short old;
 
-        if (!do_swap_account)
-                return 0;
-
         ctrl = &swap_cgroup_ctrl[type];
 
         mappage = ctrl->map[idx];
@@ -380,9 +375,6 @@ unsigned short lookup_swap_cgroup(swp_entry_t ent)
         struct swap_cgroup *sc;
         unsigned short ret;
 
-        if (!do_swap_account)
-                return 0;
-
         ctrl = &swap_cgroup_ctrl[type];
         mappage = ctrl->map[idx];
         sc = page_address(mappage);