memcg: fix gfp_mask of callers of charge

Fix misuse of gfp_kernel.

Now, most of callers of mem_cgroup_charge_xxx functions uses GFP_KERNEL.

I think that this is from the fact that page_cgroup *was* dynamically
allocated.

But now, we allocate all page_cgroup at boot.  And
mem_cgroup_try_to_free_pages() reclaim memory from GFP_HIGHUSER_MOVABLE +
specified GFP_RECLAIM_MASK.

  * This is because we just want to reduce memory usage.
    "Where we should reclaim from ?" is not a problem in memcg.

This patch modifies gfp masks to be GFP_HIGUSER_MOVABLE if possible.

Note: This patch is not for fixing behavior but for showing sane information
      in source code.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory.c b/mm/memory.c
index 7f210f1..ba5189e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2000,7 +2000,7 @@
 	cow_user_page(new_page, old_page, address, vma);
 	__SetPageUptodate(new_page);
 
-	if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
+	if (mem_cgroup_newpage_charge(new_page, mm, GFP_HIGHUSER_MOVABLE))
 		goto oom_free_new;
 
 	/*
@@ -2431,7 +2431,7 @@
 	lock_page(page);
 	delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
 
-	if (mem_cgroup_try_charge(mm, GFP_KERNEL, &ptr) == -ENOMEM) {
+	if (mem_cgroup_try_charge(mm, GFP_HIGHUSER_MOVABLE, &ptr) == -ENOMEM) {
 		ret = VM_FAULT_OOM;
 		unlock_page(page);
 		goto out;
@@ -2512,7 +2512,7 @@
 		goto oom;
 	__SetPageUptodate(page);
 
-	if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
+	if (mem_cgroup_newpage_charge(page, mm, GFP_HIGHUSER_MOVABLE))
 		goto oom_free_page;
 
 	entry = mk_pte(page, vma->vm_page_prot);
@@ -2603,7 +2603,8 @@
 				ret = VM_FAULT_OOM;
 				goto out;
 			}
-			if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
+			if (mem_cgroup_newpage_charge(page,
+						mm, GFP_HIGHUSER_MOVABLE)) {
 				ret = VM_FAULT_OOM;
 				page_cache_release(page);
 				goto out;