core/sched: added sched_change_priority() function

core/include/sched.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014 Freie Universität Berlin
+ * Copyright (C) 2014-2017 Freie Universität Berlin
  *
  * This file is subject to the terms and conditions of the GNU Lesser
  * General Public License v2.1. See the file LICENSE in the top level
@@ -75,6 +75,7 @@
  * @brief Scheduler API definition
  *
  * @author Kaspar Schleiser <kaspar@schleiser.de>
+ * @author Hauke Petersen <hauke.petersen@fu-berlin.de>
  */
 
 #ifndef SCHED_H
@@ -174,6 +175,21 @@ extern clist_node_t sched_runqueues[SCHED_PRIO_LEVELS];
  */
 NORETURN void sched_task_exit(void);
 
+#ifdef MODULE_CORE_PRIORITY_INHERITANCE
+/**
+ * @brief Change the priority of the given thread
+ *
+ * @note This functions expects interrupts to be disabled when called!
+ *
+ * @pre (thread != NULL)
+ * @pre (priority < SCHED_PRIO_LEVELS)
+ *
+ * @param[in,out] thread target thread
+ * @param[in] priority new priority to assign to @p thread
+ */
+void sched_change_priority(thread_t *thread, uint8_t priority);
+#endif
+
 #ifdef MODULE_SCHEDSTATISTICS
 /**
  * Scheduler statistics

core/sched.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014 Freie Universität Berlin
+ * Copyright (C) 2014-2017 Freie Universität Berlin
  *
  * This file is subject to the terms and conditions of the GNU Lesser
  * General Public License v2.1. See the file LICENSE in the top level
@@ -15,6 +15,7 @@
  *
  * @author Kaspar Schleiser <kaspar@schleiser.de>
  * @author René Kijewski <rene.kijewski@fu-berlin.de>
+ * @author Hauke Petersen <hauke.petersen@fu-berlin.de>
  *
  * @}
  */
@@ -79,6 +80,18 @@ static void (*sched_cb) (uint32_t timestamp, uint32_t value) = NULL;
 schedstat sched_pidlist[KERNEL_PID_LAST + 1];
 #endif
 
+static inline void runqueue_push(thread_t *thread, uint8_t priority) {
+ clist_rpush(&sched_runqueues[priority], &(thread->rq_entry));
+ runqueue_bitcache |= 1 << priority;
+}
+
+static inline void runqueue_pop(thread_t *thread) {
+ clist_lpop(&sched_runqueues[thread->priority]);
+ if (!sched_runqueues[thread->priority].next) {
+ runqueue_bitcache &= ~(1 << thread->priority);
+ }
+}
+
 int __attribute__((used)) sched_run(void)
 {
  sched_context_switch_request = 0;
@@ -164,19 +177,14 @@ void sched_set_status(thread_t *process, unsigned int status)
  if (!(process->status >= STATUS_ON_RUNQUEUE)) {
  DEBUG("sched_set_status: adding thread %" PRIkernel_pid " to runqueue %" PRIu8 ".\n",
  process->pid, process->priority);
- clist_rpush(&sched_runqueues[process->priority], &(process->rq_entry));
- runqueue_bitcache |= 1 << process->priority;
+ runqueue_push(process, process->priority);
  }
  }
  else {
  if (process->status >= STATUS_ON_RUNQUEUE) {
  DEBUG("sched_set_status: removing thread %" PRIkernel_pid " to runqueue %" PRIu8 ".\n",
  process->pid, process->priority);
- clist_lpop(&sched_runqueues[process->priority]);
-
- if (!sched_runqueues[process->priority].next) {
- runqueue_bitcache &= ~(1 << process->priority);
- }
+ runqueue_pop(process);
  }
  }
 
@@ -221,3 +229,21 @@ NORETURN void sched_task_exit(void)
  sched_active_thread = NULL;
  cpu_switch_context_exit();
 }
+
+#ifdef MODULE_CORE_PRIORITY_INHERITANCE
+void sched_change_priority(thread_t *thread, uint8_t priority)
+{
+ assert(thread && (priority < SCHED_PRIO_LEVELS));
+
+ if (thread->priority == priority) {
+ return;
+ }
+
+ if (thread->status >= STATUS_ON_RUNQUEUE) {
+ runqueue_pop(thread);
+ runqueue_push(thread, priority);
+ }
+
+ thread->priority = priority;
+}
+#endif