LITMUS^RT core: add should_wait_for_stack() callback

Allow plugins to give up when waiting for a stack to become available.

1 files changed, 7 insertions, 0 deletions

diff --git a/include/litmus/sched_plugin.h b/include/litmus/sched_plugin.h
index 0c2aabad40c9..1906a139e6e9 100644
--- a/include/litmus/sched_plugin.h
+++ b/include/litmus/sched_plugin.h
@@ -29,6 +29,12 @@ typedef struct task_struct* (*schedule_t)(struct task_struct * prev);
 typedef void (*finish_switch_t)(struct task_struct *prev);
 
 
+/* When waiting for the stack of the task selected by the plugin
+ * to become available, this callback is invoked to give the
+ * plugin a chance to cancel the wait. If the plugin returns false,
+ * the scheduler is invoked again. */
+typedef bool (*should_wait_for_stack_t)(struct task_struct *next);
+
 /********************* task state changes ********************/
 
 /* Called to setup a new real-time task.
@@ -103,6 +109,7 @@ struct sched_plugin {
         /*      scheduler invocation    */
         schedule_t              schedule;
         finish_switch_t         finish_switch;
+        should_wait_for_stack_t should_wait_for_stack;
 
         /*      syscall backend         */
         complete_job_t          complete_job;