Litmus core: simplify np-section protocolwip-2011.2-bbb

User a 32-bit word for all non-preemptive section flags.
Set the "please yield soon" flag atomically when
accessing it on remotely-scheduled tasks.

1 files changed, 11 insertions, 5 deletions

diff --git a/include/litmus/rt_param.h b/include/litmus/rt_param.h
index 389be0775869..d6d799174160 100644
--- a/include/litmus/rt_param.h
+++ b/include/litmus/rt_param.h
@@ -42,6 +42,16 @@ struct rt_task {
         budget_policy_t budget_policy; /* ignored by pfair */
 };
 
+union np_flag {
+        uint32_t raw;
+        struct {
+                /* Is the task currently in a non-preemptive section? */
+                uint32_t flag:31;
+                /* Should the task call into the scheduler? */
+                uint32_t preempt:1;
+        } np;
+};
+
 /* The definition of the data that is shared between the kernel and real-time
  * tasks via a shared page (see litmus/ctrldev.c).
  *
@@ -57,11 +67,7 @@ struct rt_task {
  * determining preemption/migration overheads).
  */
 struct control_page {
-        /* Is the task currently in a non-preemptive section? */
-        int np_flag;
-        /* Should the task call into the kernel when it leaves
-         * its non-preemptive section? */
-        int delayed_preemption;
+        volatile union np_flag sched;
 
         /* to be extended */
 };