anchao commented on code in PR #14578:
URL: https://github.com/apache/nuttx/pull/14578#discussion_r1856149288
##########
sched/sched/sched_unlock.c:
##########
@@ -40,278 +40,155 @@
* Public Functions
****************************************************************************/
-/****************************************************************************
- * Name: sched_unlock
- *
- * Description:
- * This function decrements the preemption lock count. Typically this
- * is paired with sched_lock() and concludes a critical section of
- * code. Preemption will not be unlocked until sched_unlock() has
- * been called as many times as sched_lock(). When the lockcount is
- * decremented to zero, any tasks that were eligible to preempt the
- * current task will execute.
- *
- ****************************************************************************/
-
-#ifdef CONFIG_SMP
-
-int sched_unlock(void)
+static inline_function void sched_preempt_schedule(FAR struct tcb_s *tcb)
{
- FAR struct tcb_s *rtcb;
+ bool need_leave_csection = false;
+ irqstate_t flags;
- /* This operation is safe because the scheduler is locked and no context
- * switch may occur.
- */
+ if (list_pendingtasks()->head != NULL)
+ {
+ flags = enter_critical_section_wo_note();
+ need_leave_csection = true;
- rtcb = this_task();
+ if (nxsched_merge_pending())
+ {
+ up_switch_context(this_task(), tcb);
+ }
+ }
- /* Check for some special cases: (1) rtcb may be NULL only during
- * early boot-up phases, and (2) sched_unlock() should have no
- * effect if called from the interrupt level.
+#if CONFIG_RR_INTERVAL > 0
+ /* If (1) the task that was running supported round-robin
+ * scheduling and (2) if its time slice has already expired, but
+ * (3) it could not slice out because pre-emption was disabled,
+ * then we need to swap the task out now and reassess the interval
+ * timer for the next time slice.
*/
- if (rtcb != NULL && !up_interrupt_context())
+ if ((tcb->flags & TCB_FLAG_POLICY_MASK) == TCB_FLAG_SCHED_RR &&
+ tcb->timeslice == 0)
{
- /* Prevent context switches throughout the following. */
-
- irqstate_t flags = enter_critical_section();
- int cpu = this_cpu();
-
- DEBUGASSERT(rtcb->lockcount > 0);
-
- /* Decrement the preemption lock counter */
-
- rtcb->lockcount--;
+ if (!need_leave_csection)
+ {
+ flags = enter_critical_section_wo_note();
+ need_leave_csection = true;
+ }
- /* Check if the lock counter has decremented to zero. If so,
- * then pre-emption has been re-enabled.
+ /* Yes.. that is the situation. But one more thing. The call
+ * to nxsched_merge_pending() above may have actually replaced
+ * the task at the head of the ready-to-run list. In that
+ * case, we need only to reset the timeslice value back to the
+ * maximum.
*/
- if (rtcb->lockcount <= 0)
+ if (tcb != this_task())
{
- /* Note that we no longer have pre-emption disabled. */
-
-#if CONFIG_SCHED_CRITMONITOR_MAXTIME_PREEMPTION >= 0
- nxsched_critmon_preemption(rtcb, false, return_address(0));
-#endif
-#ifdef CONFIG_SCHED_INSTRUMENTATION_PREEMPTION
- sched_note_premption(rtcb, false);
-#endif
-
- /* Release any ready-to-run tasks that have collected in
- * g_pendingtasks.
- *
- * NOTE: This operation has a very high likelihood of causing
- * this task to be switched out!
- */
-
- if (list_pendingtasks()->head != NULL)
- {
- if (nxsched_merge_pending())
- {
- up_switch_context(this_task(), rtcb);
- }
- }
-
-#if CONFIG_RR_INTERVAL > 0
- /* If (1) the task that was running supported round-robin
- * scheduling and (2) if its time slice has already expired, but
- * (3) it could not slice out because pre-emption was disabled,
- * then we need to swap the task out now and reassess the interval
- * timer for the next time slice.
- */
-
- if ((rtcb->flags & TCB_FLAG_POLICY_MASK) == TCB_FLAG_SCHED_RR &&
- rtcb->timeslice == 0)
- {
- /* Yes.. that is the situation. But one more thing. The call
- * to nxsched_merge_pending() above may have actually replaced
- * the task at the head of the ready-to-run list. In that
- * case, we need only to reset the timeslice value back to the
- * maximum.
- */
-
- if (rtcb != current_task(cpu))
- {
- rtcb->timeslice = MSEC2TICK(CONFIG_RR_INTERVAL);
- }
-#ifdef CONFIG_SCHED_TICKLESS
- else
- {
- nxsched_reassess_timer();
- }
-#endif
- }
+ tcb->timeslice = MSEC2TICK(CONFIG_RR_INTERVAL);
+ }
+# ifdef CONFIG_SCHED_TICKLESS
+ else
+ {
+ nxsched_reassess_timer();
+ }
+# endif
+ }
#endif
#ifdef CONFIG_SCHED_SPORADIC
-#if CONFIG_RR_INTERVAL > 0
- else
-#endif
- /* If (1) the task that was running supported sporadic scheduling
- * and (2) if its budget slice has already expired, but (3) it
- * could not slice out because pre-emption was disabled, then we
- * need to swap the task out now and reassess the interval timer
- * for the next time slice.
- */
-
- if ((rtcb->flags & TCB_FLAG_POLICY_MASK) == TCB_FLAG_SCHED_SPORADIC
- && rtcb->timeslice < 0)
- {
- /* Yes.. that is the situation. Force the low-priority state
- * now
- */
+# if CONFIG_RR_INTERVAL > 0
+ else
+# endif
+ /* If (1) the task that was running supported sporadic scheduling
+ * and (2) if its budget slice has already expired, but (3) it
+ * could not slice out because pre-emption was disabled, then we
+ * need to swap the task out now and reassess the interval timer
+ * for the next time slice.
+ */
- nxsched_sporadic_lowpriority(rtcb);
+ if ((tcb->flags & TCB_FLAG_POLICY_MASK) == TCB_FLAG_SCHED_SPORADIC
+ && tcb->timeslice < 0)
+ {
+ if (!need_leave_csection)
+ {
+ flags = enter_critical_section_wo_note_wo_note();
Review Comment:
let move this change to commit
https://github.com/apache/nuttx/pull/14578/commits/26967104f02cbcf5d9a07dcc1147942a3af21f87
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