Re: [PATCH 21/27] nohz: Only stop the tick on RCU nocb CPUs

From: Namhyung Kim
Date: Wed Jan 02 2013 - 03:47:23 EST

Hi Frederic,

On Sat, 29 Dec 2012 17:43:00 +0100, Frederic Weisbecker wrote:
> On a full dynticks CPU, we want the RCU callbacks to be
> offlined to another CPU, otherwise we need to keep
> the tick to wait for the grace period completion.
> Ensure the full dynticks CPU is also an rcu_nocb one.
> -static bool is_nocb_cpu(int cpu)
> -{
> - return false;
> -}
> -

You may want to add the following also to shut up the gcc:

CC kernel/rcutree.o
In file included from /home/namhyung/project/linux/kernel/rcutree.c:58:0:
/home/namhyung/project/linux/kernel/rcutree.h:539:13: warning: âis_nocb_cpuâ declared âstaticâ but never defined [-Wunused-function]


diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 4b69291b093d..fbbad931c36a 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -536,7 +536,6 @@ static void print_cpu_stall_info(struct rcu_state *rsp, int cpu);
static void print_cpu_stall_info_end(void);
static void zero_cpu_stall_ticks(struct rcu_data *rdp);
static void increment_cpu_stall_ticks(void);
-static bool is_nocb_cpu(int cpu);
static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp,
bool lazy);
static bool rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp,
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