sched: Simplify set_task_cpu()
Peter Zijlstra [Wed, 16 Dec 2009 17:04:42 +0000 (18:04 +0100)]
Rearrange code a bit now that its a simpler function.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170518.269101883@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched.c

index f92ce63..8a2bfd3 100644 (file)
@@ -2034,11 +2034,8 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
        return delta < (s64)sysctl_sched_migration_cost;
 }
 
-
 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
 {
-       int old_cpu = task_cpu(p);
-
 #ifdef CONFIG_SCHED_DEBUG
        /*
         * We should never call set_task_cpu() on a blocked task,
@@ -2049,11 +2046,11 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
 
        trace_sched_migrate_task(p, new_cpu);
 
-       if (old_cpu != new_cpu) {
-               p->se.nr_migrations++;
-               perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS,
-                                    1, 1, NULL, 0);
-       }
+       if (task_cpu(p) == new_cpu)
+               return;
+
+       p->se.nr_migrations++;
+       perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, 1, NULL, 0);
 
        __set_task_cpu(p, new_cpu);
 }