From d766506d6ae991f4459838689205ad7d2cbfe5de Mon Sep 17 00:00:00 2001
From: sasan-golchin <ahmad.golchin@mail.polimi.it>
Date: Tue, 8 Nov 2016 11:38:13 +0100
Subject: [PATCH] Control Scheduler FIX - preemption priority - less-than and
greater-than operators fixed
---
miosix/kernel/scheduler/control/control_scheduler.cpp | 3 ++-
.../kernel/scheduler/control/control_scheduler_types.h | 10 ++++++----
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/miosix/kernel/scheduler/control/control_scheduler.cpp b/miosix/kernel/scheduler/control/control_scheduler.cpp
index a774893f..8952dc4f 100644
--- a/miosix/kernel/scheduler/control/control_scheduler.cpp
+++ b/miosix/kernel/scheduler/control/control_scheduler.cpp
@@ -200,7 +200,8 @@ long long ControlScheduler::IRQgetNextPreemption()
// Should be called when the current thread is the idle thread
static inline void IRQsetNextPreemptionForIdle(){
if (sleepingList->empty())
- //normally should happen unless an IRQ is set!
+ //normally should not happen unless an IRQ is already set and able to
+ //preempt idle thread
nextPreemption = numeric_limits<long long>::max();
else
nextPreemption = sleepingList->front()->wakeup_time;
diff --git a/miosix/kernel/scheduler/control/control_scheduler_types.h b/miosix/kernel/scheduler/control/control_scheduler_types.h
index 3b423156..bcf35f99 100755
--- a/miosix/kernel/scheduler/control/control_scheduler_types.h
+++ b/miosix/kernel/scheduler/control/control_scheduler_types.h
@@ -125,13 +125,15 @@ private:
inline bool operator <(ControlSchedulerPriority a, ControlSchedulerPriority b)
{
- return (b.getRealtime() == 1 && a.getRealtime() != 1) ||
- (a.getRealtime() != 1 && b.getRealtime() != 1 && a.get() < b.get());
+ //rule 1) Idle thread should be always preempted by any thread!
+ //rule 2) Only REALTIME_PRIORITY_IMMEDIATE threads can preempt other threads
+ //right away, for other real-time priorities, the scheduler does not
+ //require to be called before the end of the current burst!
+ return a.get()==-1 || (a.getRealtime() != 1 && b.getRealtime() == 1);
}
inline bool operator>(ControlSchedulerPriority a, ControlSchedulerPriority b){
- return (a.getRealtime() == 1 && b.getRealtime() != 1) ||
- (a.getRealtime() != 1 && b.getRealtime() != 1 && a.get() > b.get());
+ return b.get()==-1 || (a.getRealtime() == 1 && b.getRealtime() != 1);
}
inline bool operator ==(ControlSchedulerPriority a, ControlSchedulerPriority b)
--
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