Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull x86 cpu offlining patch from Ingo Molnar:
 "This tree includes a single commit that speeds up x86 suspend/resume
  by replacing a naive 100msec sleep based polling loop with proper
  completion notification.

  This gives some real suspend/resume benefit on servers with larger
  core counts"

* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/smpboot: Speed up suspend/resume by avoiding 100ms sleep for CPU offline during S3

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 1c3443d98105414ab4df6e847f72a349b6072683..2d5200e56357d49f3466ce55e8ab2b3273306f68 100644 (file)
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -102,6 +102,8 @@ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
 DEFINE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);
 EXPORT_PER_CPU_SYMBOL(cpu_info);
 
+static DEFINE_PER_CPU(struct completion, die_complete);
+
 atomic_t init_deasserted;
 
 /*
@@ -1325,26 +1327,24 @@ int native_cpu_disable(void)
                return ret;
 
        clear_local_APIC();
-
+       init_completion(&per_cpu(die_complete, smp_processor_id()));
        cpu_disable_common();
+
        return 0;
 }
 
 void native_cpu_die(unsigned int cpu)
 {
        /* We don't do anything here: idle task is faking death itself. */
-       unsigned int i;
+       wait_for_completion_timeout(&per_cpu(die_complete, cpu), HZ);
 
-       for (i = 0; i < 10; i++) {
-               /* They ack this in play_dead by setting CPU_DEAD */
-               if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
-                       if (system_state == SYSTEM_RUNNING)
-                               pr_info("CPU %u is now offline\n", cpu);
-                       return;
-               }
-               msleep(100);
+       /* They ack this in play_dead() by setting CPU_DEAD */
+       if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
+               if (system_state == SYSTEM_RUNNING)
+                       pr_info("CPU %u is now offline\n", cpu);
+       } else {
+               pr_err("CPU %u didn't die...\n", cpu);
        }
-       pr_err("CPU %u didn't die...\n", cpu);
 }
 
 void play_dead_common(void)
@@ -1356,6 +1356,7 @@ void play_dead_common(void)
        mb();
        /* Ack it */
        __this_cpu_write(cpu_state, CPU_DEAD);
+       complete(&per_cpu(die_complete, smp_processor_id()));
 
        /*
         * With physical CPU hotplug, we should halt the cpu