Re: [PATCH 7/8] pipe: account to kmemcg

[Vladimir Davydov]

On Mon, May 23, 2016 at 06:39:40PM +0800, kbuild test robot wrote:
...
>    fs/built-in.o: In function `anon_pipe_buf_steal':
> >> pipe.c:(.text+0x5f8d): undefined reference to `memcg_kmem_uncharge'

From: Vladimir Davydov <vdavy...@virtuozzo.com>
Subject: [PATCH] pipe-account-to-kmemcg-fix


diff --git a/fs/pipe.c b/fs/pipe.c
index 6345f3543788..b3ad0b33f04e 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -144,8 +144,10 @@ static int anon_pipe_buf_steal(struct pipe_inode_info 
*pipe,
        struct page *page = buf->page;
 
        if (page_count(page) == 1) {
-               memcg_kmem_uncharge(page, 0);
-               __ClearPageKmemcg(page);
+               if (memcg_kmem_enabled()) {
+                       memcg_kmem_uncharge(page, 0);
+                       __ClearPageKmemcg(page);
+               }
                __SetPageLocked(page);
                return 0;
        }