[IA64] Simplify cpu_idle_wait
This is just Venki's patch[*] for x86 ported to ia64.
* http://marc.info/?l=linux-kernel&m=120249201318159&w=2
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index be6c6f7..49937a3 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -52,7 +52,6 @@
#include "sigframe.h"
void (*ia64_mark_idle)(int);
-static DEFINE_PER_CPU(unsigned int, cpu_idle_state);
unsigned long boot_option_idle_override = 0;
EXPORT_SYMBOL(boot_option_idle_override);
@@ -254,33 +253,23 @@
}
#endif /* CONFIG_HOTPLUG_CPU */
+static void do_nothing(void *unused)
+{
+}
+
+/*
+ * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
+ * pm_idle and update to new pm_idle value. Required while changing pm_idle
+ * handler on SMP systems.
+ *
+ * Caller must have changed pm_idle to the new value before the call. Old
+ * pm_idle value will not be used by any CPU after the return of this function.
+ */
void cpu_idle_wait(void)
{
- unsigned int cpu, this_cpu = get_cpu();
- cpumask_t map;
- cpumask_t tmp = current->cpus_allowed;
-
- set_cpus_allowed(current, cpumask_of_cpu(this_cpu));
- put_cpu();
-
- cpus_clear(map);
- for_each_online_cpu(cpu) {
- per_cpu(cpu_idle_state, cpu) = 1;
- cpu_set(cpu, map);
- }
-
- __get_cpu_var(cpu_idle_state) = 0;
-
- wmb();
- do {
- ssleep(1);
- for_each_online_cpu(cpu) {
- if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu))
- cpu_clear(cpu, map);
- }
- cpus_and(map, map, cpu_online_map);
- } while (!cpus_empty(map));
- set_cpus_allowed(current, tmp);
+ smp_mb();
+ /* kick all the CPUs so that they exit out of pm_idle */
+ smp_call_function(do_nothing, NULL, 0, 1);
}
EXPORT_SYMBOL_GPL(cpu_idle_wait);
@@ -308,9 +297,6 @@
#ifdef CONFIG_SMP
min_xtp();
#endif
- if (__get_cpu_var(cpu_idle_state))
- __get_cpu_var(cpu_idle_state) = 0;
-
rmb();
if (mark_idle)
(*mark_idle)(1);