From 427639354ff346710012b53e1ceed5e3f3200e0c Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Fri, 8 Feb 2008 11:53:09 -0800 Subject: [PATCH] [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 Signed-off-by: Tony Luck --- arch/ia64/kernel/process.c | 44 +++++++++++++------------------------- 1 file changed, 15 insertions(+), 29 deletions(-) diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c index be6c6f7be02..49937a383b2 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 @@ static inline void play_dead(void) } #endif /* CONFIG_HOTPLUG_CPU */ -void cpu_idle_wait(void) +static void do_nothing(void *unused) { - 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); +/* + * 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) +{ + 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 @@ cpu_idle (void) #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); -- 2.41.0