[PATCH] Makefiles: Disable unused-variable warning (was: Re: [PATCH 1/6] memcg: fix unused variable warning)

Kirill A. Shutemov kirill at shutemov.name
Tue Dec 27 18:26:13 UTC 2011


On Tue, Dec 27, 2011 at 02:57:52PM +0100, Michal Hocko wrote:
> On Sat 24-12-11 05:00:14, Kirill A. Shutemov wrote:
> > From: "Kirill A. Shutemov" <kirill at shutemov.name>
> > 
> > mm/memcontrol.c: In function ‘memcg_check_events’:
> > mm/memcontrol.c:784:22: warning: unused variable ‘do_numainfo’ [-Wunused-variable]
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill at shutemov.name>
> > ---
> >  mm/memcontrol.c |    7 ++++---
> >  1 files changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index d643bd6..a5e92bd 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -781,14 +781,15 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
> >  	/* threshold event is triggered in finer grain than soft limit */
> >  	if (unlikely(mem_cgroup_event_ratelimit(memcg,
> >  						MEM_CGROUP_TARGET_THRESH))) {
> > -		bool do_softlimit, do_numainfo;
> > +		bool do_softlimit;
> >  
> > -		do_softlimit = mem_cgroup_event_ratelimit(memcg,
> > -						MEM_CGROUP_TARGET_SOFTLIMIT);
> >  #if MAX_NUMNODES > 1
> > +		bool do_numainfo;
> >  		do_numainfo = mem_cgroup_event_ratelimit(memcg,
> >  						MEM_CGROUP_TARGET_NUMAINFO);
> >  #endif
> > +		do_softlimit = mem_cgroup_event_ratelimit(memcg,
> > +						MEM_CGROUP_TARGET_SOFTLIMIT);
> 
> I don't like this very much. Maybe we should get rid of both do_* and
> do it with flags? But maybe it is not worth the additional code at
> all...

Something like this (untested):

====
From f57e1a2e1aaaa167c75b963d5bf12fcbdd3331b8 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill at shutemov.name>
Date: Tue, 27 Dec 2011 20:17:13 +0200
Subject: [PATCH] memcg: cleanup memcg_check_events()

Signed-off-by: Kirill A. Shutemov <kirill at shutemov.name>
---
 mm/memcontrol.c |   42 ++++++++++++++++++++++++------------------
 1 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d643bd6..40c2236 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -108,11 +108,12 @@ enum mem_cgroup_events_index {
  * than using jiffies etc. to handle periodic memcg event.
  */
 enum mem_cgroup_events_target {
-	MEM_CGROUP_TARGET_THRESH,
-	MEM_CGROUP_TARGET_SOFTLIMIT,
-	MEM_CGROUP_TARGET_NUMAINFO,
-	MEM_CGROUP_NTARGETS,
+	MEM_CGROUP_TARGET_THRESH	= BIT(1),
+	MEM_CGROUP_TARGET_SOFTLIMIT	= BIT(2),
+	MEM_CGROUP_TARGET_NUMAINFO	= BIT(3),
 };
+#define MEM_CGROUP_NTARGETS 3
+
 #define THRESHOLDS_EVENTS_TARGET (128)
 #define SOFTLIMIT_EVENTS_TARGET (1024)
 #define NUMAINFO_EVENTS_TARGET	(1024)
@@ -743,7 +744,7 @@ static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
 	return total;
 }
 
-static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
+static int mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
 				       enum mem_cgroup_events_target target)
 {
 	unsigned long val, next;
@@ -766,9 +767,9 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
 			break;
 		}
 		__this_cpu_write(memcg->stat->targets[target], next);
-		return true;
+		return target;
 	}
-	return false;
+	return 0;
 }
 
 /*
@@ -777,29 +778,34 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
  */
 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
 {
+	int flags;
+
 	preempt_disable();
-	/* threshold event is triggered in finer grain than soft limit */
-	if (unlikely(mem_cgroup_event_ratelimit(memcg,
-						MEM_CGROUP_TARGET_THRESH))) {
-		bool do_softlimit, do_numainfo;
+	flags = mem_cgroup_event_ratelimit(memcg, MEM_CGROUP_TARGET_THRESH);
 
-		do_softlimit = mem_cgroup_event_ratelimit(memcg,
+	/*
+	 * Threshold event is triggered in finer grain than soft limit
+	 * and numainfo
+	 */
+	if (unlikely(flags)) {
+		flags |= mem_cgroup_event_ratelimit(memcg,
 						MEM_CGROUP_TARGET_SOFTLIMIT);
 #if MAX_NUMNODES > 1
-		do_numainfo = mem_cgroup_event_ratelimit(memcg,
+		flags |= mem_cgroup_event_ratelimit(memcg,
 						MEM_CGROUP_TARGET_NUMAINFO);
 #endif
-		preempt_enable();
+	}
+	preempt_enable();
 
+	if (unlikely(flags)) {
 		mem_cgroup_threshold(memcg);
-		if (unlikely(do_softlimit))
+		if (unlikely(flags & MEM_CGROUP_TARGET_SOFTLIMIT))
 			mem_cgroup_update_tree(memcg, page);
 #if MAX_NUMNODES > 1
-		if (unlikely(do_numainfo))
+		if (unlikely(flags & MEM_CGROUP_TARGET_NUMAINFO))
 			atomic_inc(&memcg->numainfo_events);
 #endif
-	} else
-		preempt_enable();
+	}
 }
 
 struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
-- 
1.7.7.3

-- 
 Kirill A. Shutemov


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