From e69aab13117efc1987620090e539b4ebeb33a04c Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 26 Feb 2016 18:43:43 +0000
Subject: cpu/hotplug: Make wait for dead cpu completion based

Kill the busy spinning on the control side and just wait for the hotplugged
cpu to tell that it reached the dead state.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Rik van Riel <riel@redhat.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/20160226182341.776157858@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/sched/idle.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

(limited to 'kernel/sched')

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index a4b9813afc96..8abbe89e9114 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -194,8 +194,6 @@ exit_idle:
 	rcu_idle_exit();
 }
 
-DEFINE_PER_CPU(bool, cpu_dead_idle);
-
 /*
  * Generic idle loop implementation
  *
@@ -224,8 +222,7 @@ static void cpu_idle_loop(void)
 			if (cpu_is_offline(smp_processor_id())) {
 				rcu_cpu_notify(NULL, CPU_DYING_IDLE,
 					       (void *)(long)smp_processor_id());
-				smp_mb(); /* all activity before dead. */
-				this_cpu_write(cpu_dead_idle, true);
+				cpuhp_report_idle_dead();
 				arch_cpu_idle_dead();
 			}
 
-- 
cgit v1.2.1