Move SEND_RESCHED tracing to preempt.c

The SEND_RESCHED is really only interesting if the IPI was generated
by LITMUS^RT. Therefore, we don't need to trace in Linux's
architecture-specific code. Instead, we hook into the preemption state
machine, which is informed about incoming IPIs anyway.

2 files changed, 10 insertions, 10 deletions

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index f5e294040b1c..7539d84628f7 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -25,7 +25,6 @@
 
 #include <litmus/preempt.h>
 #include <litmus/debug_trace.h>
-#include <litmus/trace.h>
 
 #include <asm/mtrr.h>
 #include <asm/tlbflush.h>
@@ -122,7 +121,6 @@ static void native_smp_send_reschedule(int cpu)
                 WARN_ON(1);
                 return;
         }
-        TS_SEND_RESCHED_START(cpu);
         apic->send_IPI_mask(cpumask_of(cpu), RESCHEDULE_VECTOR);
 }
 
@@ -214,18 +212,16 @@ static void native_stop_other_cpus(int wait)
 void smp_reschedule_interrupt(struct pt_regs *regs)
 {
         ack_APIC_irq();
-        /* 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
          */
+
+        /* LITMUS^RT: this IPI might need to trigger the sched state machine.
+         * Starting from 3.0 schedule_ipi() actually does something.  This may
+         * increase IPI latencies compared with previous versions. */
+        sched_state_ipi();
 }
 
 void smp_call_function_interrupt(struct pt_regs *regs)
diff --git a/litmus/preempt.c b/litmus/preempt.c
index 5704d0bf4c0b..6be2f26728b8 100644
--- a/litmus/preempt.c
+++ b/litmus/preempt.c
@@ -2,6 +2,7 @@
 
 #include <litmus/litmus.h>
 #include <litmus/preempt.h>
+#include <litmus/trace.h>
 
 /* The rescheduling state of each processor.
  */
@@ -47,6 +48,7 @@ void sched_state_ipi(void)
                 set_tsk_need_resched(current);
                 TRACE_STATE("IPI -> set_tsk_need_resched(%s/%d)\n",
                             current->comm, current->pid);
+                TS_SEND_RESCHED_END;
         } else {
                 /* ignore */
                 TRACE_STATE("ignoring IPI in state %x (%s)\n",
@@ -85,8 +87,10 @@ void litmus_reschedule(int cpu)
         if (scheduled_transition_ok) {
                 if (smp_processor_id() == cpu)
                         set_tsk_need_resched(current);
-                else
+                else {
+                        TS_SEND_RESCHED_START(cpu);
                         smp_send_reschedule(cpu);
+                }
         }
 
         TRACE_STATE("%s picked-ok:%d sched-ok:%d\n",