memcg: remove redundant message at swapon

It's pointed out that swap_cgroup's message at swapon() is nonsense.
Because

  * It can be calculated very easily if all necessary information is
    written in Kconfig.

  * It's not necessary to annoying people at every swapon().

In other view, now, memory usage per swp_entry is reduced to 2bytes from
8bytes(64bit) and I think it's reasonably small.

Reported-by: Hugh Dickins <hugh@veritas.com>
Signed-off-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, 2 insertions, 7 deletions

diff --git a/init/Kconfig b/init/Kconfig
index 14c483d2b7c9..92d410603932 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -597,6 +597,8 @@ config CGROUP_MEM_RES_CTLR_SWAP
           is disabled by boot option, this will be automatically disabled and
           there will be no overhead from this. Even when you set this config=y,
           if boot option "noswapaccount" is set, swap will not be accounted.
+          Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
+          size is 4096bytes, 512k per 1Gbytes of swap.
 
 endif # CGROUPS
 
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index ebf81074bed4..791905c991df 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -426,13 +426,6 @@ int swap_cgroup_swapon(int type, unsigned long max_pages)
         }
         mutex_unlock(&swap_cgroup_mutex);
 
-        printk(KERN_INFO
-                "swap_cgroup: uses %ld bytes of vmalloc for pointer array space"
-                " and %ld bytes to hold mem_cgroup information per swap ents\n",
-                array_size, length * PAGE_SIZE);
-        printk(KERN_INFO
-        "swap_cgroup can be disabled by noswapaccount boot option.\n");
-
         return 0;
 nomem:
         printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.\n");