Re: [PATCH v2 1/3] vmscan,memcg: memcg aware swap token

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

> CONFIG_CGROUPS=n:
> 
> mm/thrash.c: In function 'grab_swap_token':
> mm/thrash.c:73: error: implicit declaration of function 'css_put'
> 
> I don't think that adding a null stub for css_put() is the right fix
> here...

My bad. Following patch fixes this issue.

Thanks.



>From 6a824b46219cb2f11b125e9a33f65e0f01899d09 Mon Sep 17 00:00:00 2001
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Date: Mon, 30 May 2011 15:47:32 +0900
Subject: [PATCH] swap-token: fix compilation error when CONFIG_CGROUPS=n

Andrew Morton pointed out css_put() is not defined when
CONFIG_CGROUPS=n.

: CONFIG_CGROUPS=n:
:
: mm/thrash.c: In function 'grab_swap_token':
: mm/thrash.c:73: error: implicit declaration of function 'css_put'

Thus, this patch move the whole logic into CONFIG_CGROUP_MEM_RES_CTLR
condtion.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
 mm/thrash.c |   24 +++++++++++++++++++-----
 1 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/mm/thrash.c b/mm/thrash.c
index 8832edb..cd06606 100644
--- a/mm/thrash.c
+++ b/mm/thrash.c
@@ -31,11 +31,28 @@ static DEFINE_SPINLOCK(swap_token_lock);
 struct mm_struct *swap_token_mm;
 struct mem_cgroup *swap_token_memcg;

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+static struct mem_cgroup* swap_token_memcg_from_mm(struct mm_struct *mm)
+{
+	struct mem_cgroup *memcg;
+
+	memcg = try_get_mem_cgroup_from_mm(mm);
+	if (memcg)
+		css_put(mem_cgroup_css(memcg));
+
+	return memcg;
+}
+#else
+static struct mem_cgroup* swap_token_memcg_from_mm(struct mm_struct *mm)
+{
+	return NULL;
+}
+#endif
+
 void grab_swap_token(struct mm_struct *mm)
 {
 	int current_interval;
 	unsigned int old_prio = mm->token_priority;
-	struct mem_cgroup *memcg;
 	static unsigned int global_faults;
 	static unsigned int last_aging;

@@ -93,12 +110,9 @@ out:

 replace_token:
 	mm->token_priority += 2;
-	memcg = try_get_mem_cgroup_from_mm(mm);
-	if (memcg)
-		css_put(mem_cgroup_css(memcg));
 	trace_replace_swap_token(swap_token_mm, mm);
 	swap_token_mm = mm;
-	swap_token_memcg = memcg;
+	swap_token_memcg = swap_token_memcg_from_mm(mm);
 	last_aging = global_faults;
 	goto out;
 }
-- 
1.7.3.1