Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp

Conflicts:
	litmus/sched_cedf.c

1 files changed, 15 insertions, 9 deletions

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 74cca6014c0e..ed4c4f54e2ae 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -174,10 +174,10 @@ asmlinkage void smp_reboot_interrupt(void)
         irq_exit();
 }
 
-static void native_smp_send_stop(void)
+static void native_stop_other_cpus(int wait)
 {
         unsigned long flags;
-        unsigned long wait;
+        unsigned long timeout;
 
         if (reboot_force)
                 return;
@@ -194,9 +194,12 @@ static void native_smp_send_stop(void)
         if (num_online_cpus() > 1) {
                 apic->send_IPI_allbutself(REBOOT_VECTOR);
 
-                /* Don't wait longer than a second */
-                wait = USEC_PER_SEC;
-                while (num_online_cpus() > 1 && wait--)
+                /*
+                 * Don't wait longer than a second if the caller
+                 * didn't ask us to wait.
+                 */
+                timeout = USEC_PER_SEC;
+                while (num_online_cpus() > 1 && (wait || timeout--))
                         udelay(1);
         }
 
@@ -206,9 +209,7 @@ static void native_smp_send_stop(void)
 }
 
 /*
- * Reschedule call back. Nothing to do,
- * all the work is done automatically when
- * we return from the interrupt.
+ * Reschedule call back.
  */
 void smp_reschedule_interrupt(struct pt_regs *regs)
 {
@@ -216,6 +217,11 @@ void smp_reschedule_interrupt(struct pt_regs *regs)
         /* LITMUS^RT: this IPI might need to trigger the sched state machine. */
         sched_state_ipi();
         inc_irq_stat(irq_resched_count);
+        /*
+         * LITMUS^RT: starting from 3.0 schedule_ipi() actually does something.
+         * This may increase IPI latencies compared with previous versions.
+         */
+        scheduler_ipi();
         TS_SEND_RESCHED_END;
         /*
          * KVM uses this interrupt to force a cpu out of guest mode
@@ -254,7 +260,7 @@ struct smp_ops smp_ops = {
         .smp_prepare_cpus       = native_smp_prepare_cpus,
         .smp_cpus_done          = native_smp_cpus_done,
 
-        .smp_send_stop          = native_smp_send_stop,
+        .stop_other_cpus        = native_stop_other_cpus,
         .smp_send_reschedule    = native_smp_send_reschedule,
 
         .cpu_up                 = native_cpu_up,