Allow scheduler to 'logically' remove crit_entry's from level-C heap.

This required fixes to hrtimer_start_on code so that events can be cancelled
or re-armed while an hrtimer pull is in progress.

1 files changed, 17 insertions, 2 deletions

diff --git a/include/litmus/sched_mc.h b/include/litmus/sched_mc.h
index d67a7bfc470c..0a1b3f0c718c 100644
--- a/include/litmus/sched_mc.h
+++ b/include/litmus/sched_mc.h
@@ -26,7 +26,6 @@ struct mc_job {
  * These are used only in the kernel. Userspace programs like RTSpin won't see
  * them.
  */
-
 struct mc_data {
         struct mc_task mc_task;
         struct mc_job mc_job;
@@ -62,6 +61,22 @@ struct ce_dom_data {
 };
 
 /**
+ * enum crit_state - Logically add / remove CPUs from criticality levels.
+ *
+ * Global crit levels need to use a two step process to remove CPUs so
+ * that the CPUs can be removed without holding domain locks.
+ *
+ * @CS_ACTIVE   The criticality entry can run a task
+ * @CS_ACTIVATE The criticality entry can run a task, but hasn't had its
+ *              position updated in a global heap. Set with ONLY CPU lock.
+ * @CS_REMOVE   The criticality entry is logically removed, but hasn't had its
+ *              position adjusted in a global heap. This should be set when
+ *              ONLY the CPU state is locked.
+ * @CS_REMOVED  The criticality entry has been removed from the crit level
+ */
+enum crit_state { CS_ACTIVE, CS_ACTIVATE, CS_REMOVE, CS_REMOVED };
+
+/**
  * struct crit_entry - State of a CPU within each criticality level system.
  * @level       Criticality level of this entry
  * @linked      Logically running task, ghost or regular
@@ -75,7 +90,7 @@ struct crit_entry {
         enum crit_level         level;
         struct task_struct*     linked;
         struct domain*          domain;
-        int                     usable;
+        enum crit_state         state;
 #ifdef CONFIG_MERGE_TIMERS
         struct rt_event         event;
 #else