From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 3 Jul 2009 08:30:27 -0500
Subject: stop_machine: convert stop_machine_run() to PREEMPT_RT
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: 80184c5d14205abd7de8e7e4380c809fbdf7c95c
Patch-mainline: Queued in subsystem maintainer repository
References: SLE Realtime Extension
Instead of playing with non-preemption, introduce explicit
startup serialization. This is more robust and cleaner as
well.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bigeasy: XXX: stopper_lock -> stop_cpus_lock]
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
---
kernel/stop_machine.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -475,6 +475,16 @@ static void cpu_stopper_thread(unsigned
struct cpu_stop_done *done = work->done;
int ret;
+ /*
+ * Wait until the stopper finished scheduling on all
+ * cpus
+ */
+ lg_global_lock(&stop_cpus_lock);
+ /*
+ * Let other cpu threads continue as well
+ */
+ lg_global_unlock(&stop_cpus_lock);
+
/* cpu stop callbacks must not sleep, make in_atomic() == T */
preempt_count_inc();
ret = fn(arg);