From 4b69d7ea03c8f171e6819a793217b02650d37997 Mon Sep 17 00:00:00 2001
From: Terraneo Federico <fede.tft@miosix.org>
Date: Sun, 26 Mar 2023 14:35:15 +0200
Subject: [PATCH] Implement timedWait also in class ConditonVariable
---
miosix/kernel/kernel.h | 20 ++--
miosix/kernel/pthread.cpp | 79 +++++++++-------
miosix/kernel/pthread_private.h | 14 +--
miosix/kernel/sync.cpp | 163 ++++++++++++++++++--------------
miosix/kernel/sync.h | 90 +++++++++++++-----
5 files changed, 216 insertions(+), 150 deletions(-)
diff --git a/miosix/kernel/kernel.h b/miosix/kernel/kernel.h
index c7eb36af..7c8c054f 100755
--- a/miosix/kernel/kernel.h
+++ b/miosix/kernel/kernel.h
@@ -1039,18 +1039,18 @@ private:
//friend functions
//Need access to status
- friend void IRQaddToSleepingList(SleepData *x);
+ friend void IRQaddToSleepingList(SleepData *);
//Need access to status
- friend void IRQremoveFromSleepingList(SleepData *x);
+ friend void IRQremoveFromSleepingList(SleepData *);
//Needs access to status
- friend bool IRQwakeThreads(long long currentTick);
+ friend bool IRQwakeThreads(long long);
//Needs access to watermark, status, next
- friend void *idleThread(void *argv);
+ friend void *idleThread(void *);
//Needs to create the idle thread
friend void startKernel();
//Needs threadLauncher
- friend void miosix_private::initCtxsave(unsigned int *ctxsave,
- void *(*pc)(void *), unsigned int *sp, void *argv);
+ friend void miosix_private::initCtxsave(unsigned int *, void *(*)(void *),
+ unsigned int *, void *);
//Needs access to priority, savedPriority, mutexLocked and flags.
friend class Mutex;
//Needs access to flags
@@ -1062,13 +1062,13 @@ private:
//Needs access to flags, schedData
friend class EDFScheduler;
//Needs access to flags
- friend int ::pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex);
+ friend int ::pthread_cond_wait(pthread_cond_t *, pthread_mutex_t *);
//Needs access to flags
- friend int ::pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, const struct timespec *abstime);
+ friend int pthreadCondTimedWaitImpl(pthread_cond_t *, pthread_mutex_t *, long long);
//Needs access to flags
- friend int ::pthread_cond_signal(pthread_cond_t *cond);
+ friend int ::pthread_cond_signal(pthread_cond_t *);
//Needs access to flags
- friend int ::pthread_cond_broadcast(pthread_cond_t *cond);
+ friend int ::pthread_cond_broadcast(pthread_cond_t *);
//Needs access to cppReent
friend class CppReentrancyAccessor;
#ifdef WITH_PROCESSES
diff --git a/miosix/kernel/pthread.cpp b/miosix/kernel/pthread.cpp
index 37446505..f91bfa80 100644
--- a/miosix/kernel/pthread.cpp
+++ b/miosix/kernel/pthread.cpp
@@ -1,5 +1,5 @@
/***************************************************************************
- * Copyright (C) 2010, 2011 by Terraneo Federico *
+ * Copyright (C) 2010-2023 by Terraneo Federico *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
@@ -330,41 +330,7 @@ int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, const struct timespec *abstime)
{
- auto *condList=reinterpret_cast<IntrusiveList<CondData>*>(cond);
-
- long long timeout=timespec2ll(abstime);
- //Disallow absolute sleeps with negative or too low values, as the ns2tick()
- //algorithm in TimeConversion can't handle negative values and may undeflow
- //even with very low values due to a negative adjustOffsetNs. As an unlikely
- //side effect, very shor sleeps done very early at boot will be extended.
- timeout=std::max(timeout,100000LL);
- FastInterruptDisableLock dLock;
- Thread *p=Thread::IRQgetCurrentThread();
- CondData listItem;
- listItem.thread=p;
- condList->push_back(&listItem); //Putting this thread last on the list (lifo policy)
- SleepData sleepData;
- sleepData.p=p;
- sleepData.wakeupTime=timeout;
- IRQaddToSleepingList(&sleepData); //Putting this thread on the sleeping list too
- p->flags.IRQsetCondWait(true);
-
- unsigned int depth=IRQdoMutexUnlockAllDepthLevels(mutex);
- {
- FastInterruptEnableLock eLock(dLock);
- Thread::yield(); //Here the wait becomes effective
- }
- //Ensure that the thread is removed from both list, as it can be woken by
- //either a signal/broadcast (that removes it from condList) or by
- //IRQwakeThreads (that removes it from sleeping list).
- bool removed=condList->removeFast(&listItem);
- IRQremoveFromSleepingList(&sleepData);
-
- IRQdoMutexLockToDepth(mutex,dLock,depth);
-
- //If the thread was still in the cond variable list, it was woken up by a timeout
- if(removed) return ETIMEDOUT;
- return 0;
+ return pthreadCondTimedWaitImpl(cond,mutex,timespec2ll(abstime));
}
int pthread_cond_signal(pthread_cond_t *cond)
@@ -473,3 +439,44 @@ int pthread_once(pthread_once_t *once, void (*func)())
int pthread_setcancelstate(int state, int *oldstate) { return 0; } //Stub
} //extern "C"
+
+namespace miosix {
+
+int pthreadCondTimedWaitImpl(pthread_cond_t *cond, pthread_mutex_t *mutex, long long absTime)
+{
+ auto *condList=reinterpret_cast<IntrusiveList<CondData>*>(cond);
+
+ //Disallow absolute sleeps with negative or too low values, as the ns2tick()
+ //algorithm in TimeConversion can't handle negative values and may undeflow
+ //even with very low values due to a negative adjustOffsetNs. As an unlikely
+ //side effect, very shor sleeps done very early at boot will be extended.
+ absTime=std::max(absTime,100000LL);
+ FastInterruptDisableLock dLock;
+ Thread *p=Thread::IRQgetCurrentThread();
+ CondData listItem;
+ listItem.thread=p;
+ condList->push_back(&listItem); //Putting this thread last on the list (lifo policy)
+ SleepData sleepData;
+ sleepData.p=p;
+ sleepData.wakeupTime=absTime;
+ IRQaddToSleepingList(&sleepData); //Putting this thread on the sleeping list too
+ p->flags.IRQsetCondWait(true);
+
+ unsigned int depth=IRQdoMutexUnlockAllDepthLevels(mutex);
+ {
+ FastInterruptEnableLock eLock(dLock);
+ Thread::yield(); //Here the wait becomes effective
+ }
+ //Ensure that the thread is removed from both list, as it can be woken by
+ //either a signal/broadcast (that removes it from condList) or by
+ //IRQwakeThreads (that removes it from sleeping list).
+ bool removed=condList->removeFast(&listItem);
+ IRQremoveFromSleepingList(&sleepData);
+
+ IRQdoMutexLockToDepth(mutex,dLock,depth);
+
+ //If the thread was still in the cond variable list, it was woken up by a timeout
+ return removed ? ETIMEDOUT : 0;
+}
+
+} //namespace miosix
diff --git a/miosix/kernel/pthread_private.h b/miosix/kernel/pthread_private.h
index 2dc4cd71..1c43e211 100644
--- a/miosix/kernel/pthread_private.h
+++ b/miosix/kernel/pthread_private.h
@@ -1,5 +1,5 @@
/***************************************************************************
- * Copyright (C) 2011 by Terraneo Federico *
+ * Copyright (C) 2011-2023 by Terraneo Federico *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
@@ -33,6 +33,7 @@
#include <pthread.h>
#include "kernel.h"
#include "intrusive.h"
+#include "sync.h"
namespace miosix {
@@ -219,15 +220,6 @@ static inline unsigned int IRQdoMutexUnlockAllDepthLevels(pthread_mutex_t *mutex
return result;
}
-/**
- * \internal
- * \struct CondData
- * This struct is used to make a list of threads that are waiting on a condition
- * variable. It is used by the kernel, and should not be used by end users.
- */
-struct CondData : public IntrusiveListItem
-{
- Thread *thread; ///<\internal Thread that is waiting
-};
+int pthreadCondTimedWaitImpl(pthread_cond_t *cond, pthread_mutex_t *mutex, long long absTime);
} //namespace miosix
diff --git a/miosix/kernel/sync.cpp b/miosix/kernel/sync.cpp
index ceb01c48..8a7d4256 100644
--- a/miosix/kernel/sync.cpp
+++ b/miosix/kernel/sync.cpp
@@ -1,5 +1,5 @@
/***************************************************************************
- * Copyright (C) 2008, 2009, 2010, 2011 by Terraneo Federico *
+ * Copyright (C) 2008-2023 by Terraneo Federico *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
@@ -24,7 +24,6 @@
* You should have received a copy of the GNU General Public License *
* along with this program; if not, see <http://www.gnu.org/licenses/> *
***************************************************************************/
- //Miosix kernel
#include "sync.h"
#include "kernel.h"
@@ -37,11 +36,14 @@ using namespace std;
namespace miosix {
+void IRQaddToSleepingList(SleepData *x);
+void IRQremoveFromSleepingList(SleepData *x);
+
//
// class Mutex
//
-Mutex::Mutex(Options opt): owner(0), next(0), waiting()
+Mutex::Mutex(Options opt): owner(nullptr), next(nullptr), waiting()
{
recursiveDepth= opt==RECURSIVE ? 0 : -1;
}
@@ -49,12 +51,12 @@ Mutex::Mutex(Options opt): owner(0), next(0), waiting()
void Mutex::PKlock(PauseKernelLock& dLock)
{
Thread *p=Thread::getCurrentThread();
- if(owner==0)
+ if(owner==nullptr)
{
owner=p;
//Save original thread priority, if the thread has not yet locked
//another mutex
- if(owner->mutexLocked==0) owner->savedPriority=owner->getPriority();
+ if(owner->mutexLocked==nullptr) owner->savedPriority=owner->getPriority();
//Add this mutex to the list of mutexes locked by owner
this->next=owner->mutexLocked;
owner->mutexLocked=this;
@@ -79,7 +81,7 @@ void Mutex::PKlock(PauseKernelLock& dLock)
push_heap(waiting.begin(),waiting.end(),l);
//Handle priority inheritance
- if(p->mutexWaiting!=0) errorHandler(UNEXPECTED);
+ if(p->mutexWaiting!=nullptr) errorHandler(UNEXPECTED);
p->mutexWaiting=this;
if (owner->getPriority().mutexLessOp(p->getPriority()))
{
@@ -87,7 +89,7 @@ void Mutex::PKlock(PauseKernelLock& dLock)
for(;;)
{
Scheduler::PKsetPriority(walk,p->getPriority());
- if(walk->mutexWaiting==0) break;
+ if(walk->mutexWaiting==nullptr) break;
make_heap(walk->mutexWaiting->waiting.begin(),
walk->mutexWaiting->waiting.end(),l);
walk=walk->mutexWaiting->owner;
@@ -117,13 +119,13 @@ void Mutex::PKlock(PauseKernelLock& dLock)
void Mutex::PKlockToDepth(PauseKernelLock& dLock, unsigned int depth)
{
Thread *p=Thread::getCurrentThread();
- if(owner==0)
+ if(owner==nullptr)
{
owner=p;
if(recursiveDepth>=0) recursiveDepth=depth;
//Save original thread priority, if the thread has not yet locked
//another mutex
- if(owner->mutexLocked==0) owner->savedPriority=owner->getPriority();
+ if(owner->mutexLocked==nullptr) owner->savedPriority=owner->getPriority();
//Add this mutex to the list of mutexes locked by owner
this->next=owner->mutexLocked;
owner->mutexLocked=this;
@@ -148,7 +150,7 @@ void Mutex::PKlockToDepth(PauseKernelLock& dLock, unsigned int depth)
push_heap(waiting.begin(),waiting.end(),l);
//Handle priority inheritance
- if(p->mutexWaiting!=0) errorHandler(UNEXPECTED);
+ if(p->mutexWaiting!=nullptr) errorHandler(UNEXPECTED);
p->mutexWaiting=this;
if (owner->getPriority().mutexLessOp(p->getPriority()))
{
@@ -156,7 +158,7 @@ void Mutex::PKlockToDepth(PauseKernelLock& dLock, unsigned int depth)
for(;;)
{
Scheduler::PKsetPriority(walk,p->getPriority());
- if(walk->mutexWaiting==0) break;
+ if(walk->mutexWaiting==nullptr) break;
make_heap(walk->mutexWaiting->waiting.begin(),
walk->mutexWaiting->waiting.end(),l);
walk=walk->mutexWaiting->owner;
@@ -187,12 +189,12 @@ void Mutex::PKlockToDepth(PauseKernelLock& dLock, unsigned int depth)
bool Mutex::PKtryLock(PauseKernelLock& dLock)
{
Thread *p=Thread::getCurrentThread();
- if(owner==0)
+ if(owner==nullptr)
{
owner=p;
//Save original thread priority, if the thread has not yet locked
//another mutex
- if(owner->mutexLocked==0) owner->savedPriority=owner->getPriority();
+ if(owner->mutexLocked==nullptr) owner->savedPriority=owner->getPriority();
//Add this mutex to the list of mutexes locked by owner
this->next=owner->mutexLocked;
owner->mutexLocked=this;
@@ -226,7 +228,7 @@ bool Mutex::PKunlock(PauseKernelLock& dLock)
for(;;)
{
//this Mutex not in owner's list? impossible
- if(walk->next==0) errorHandler(UNEXPECTED);
+ if(walk->next==nullptr) errorHandler(UNEXPECTED);
if(walk->next==this)
{
walk->next=walk->next->next;
@@ -237,7 +239,7 @@ bool Mutex::PKunlock(PauseKernelLock& dLock)
}
//Handle priority inheritance
- if(owner->mutexLocked==0)
+ if(owner->mutexLocked==nullptr)
{
//Not locking any other mutex
if(owner->savedPriority!=owner->getPriority())
@@ -247,7 +249,7 @@ bool Mutex::PKunlock(PauseKernelLock& dLock)
//Calculate new priority of thread, which is
//max(savedPriority, inheritedPriority)
Mutex *walk=owner->mutexLocked;
- while(walk!=0)
+ while(walk!=nullptr)
{
if(walk->waiting.empty()==false)
if (pr.mutexLessOp(walk->waiting.front()->getPriority()))
@@ -266,9 +268,9 @@ bool Mutex::PKunlock(PauseKernelLock& dLock)
pop_heap(waiting.begin(),waiting.end(),l);
waiting.pop_back();
if(owner->mutexWaiting!=this) errorHandler(UNEXPECTED);
- owner->mutexWaiting=0;
+ owner->mutexWaiting=nullptr;
owner->PKwakeup();
- if(owner->mutexLocked==0) owner->savedPriority=owner->getPriority();
+ if(owner->mutexLocked==nullptr) owner->savedPriority=owner->getPriority();
//Add this mutex to the list of mutexes locked by owner
this->next=owner->mutexLocked;
owner->mutexLocked=this;
@@ -278,7 +280,7 @@ bool Mutex::PKunlock(PauseKernelLock& dLock)
Scheduler::PKsetPriority(owner,waiting.front()->getPriority());
return p->getPriority().mutexLessOp(owner->getPriority());
} else {
- owner=0; //No threads waiting
+ owner=nullptr; //No threads waiting
std::vector<Thread *>().swap(waiting); //Save some RAM
return false;
}
@@ -298,7 +300,7 @@ unsigned int Mutex::PKunlockAllDepthLevels(PauseKernelLock& dLock)
for(;;)
{
//this Mutex not in owner's list? impossible
- if(walk->next==0) errorHandler(UNEXPECTED);
+ if(walk->next==nullptr) errorHandler(UNEXPECTED);
if(walk->next==this)
{
walk->next=walk->next->next;
@@ -309,7 +311,7 @@ unsigned int Mutex::PKunlockAllDepthLevels(PauseKernelLock& dLock)
}
//Handle priority inheritance
- if(owner->mutexLocked==0)
+ if(owner->mutexLocked==nullptr)
{
//Not locking any other mutex
if(owner->savedPriority!=owner->getPriority())
@@ -319,7 +321,7 @@ unsigned int Mutex::PKunlockAllDepthLevels(PauseKernelLock& dLock)
//Calculate new priority of thread, which is
//max(savedPriority, inheritedPriority)
Mutex *walk=owner->mutexLocked;
- while(walk!=0)
+ while(walk!=nullptr)
{
if(walk->waiting.empty()==false)
if (pr.mutexLessOp(walk->waiting.front()->getPriority()))
@@ -338,9 +340,9 @@ unsigned int Mutex::PKunlockAllDepthLevels(PauseKernelLock& dLock)
pop_heap(waiting.begin(),waiting.end(),l);
waiting.pop_back();
if(owner->mutexWaiting!=this) errorHandler(UNEXPECTED);
- owner->mutexWaiting=0;
+ owner->mutexWaiting=nullptr;
owner->PKwakeup();
- if(owner->mutexLocked==0) owner->savedPriority=owner->getPriority();
+ if(owner->mutexLocked==nullptr) owner->savedPriority=owner->getPriority();
//Add this mutex to the list of mutexes locked by owner
this->next=owner->mutexLocked;
owner->mutexLocked=this;
@@ -349,7 +351,7 @@ unsigned int Mutex::PKunlockAllDepthLevels(PauseKernelLock& dLock)
owner->getPriority().mutexLessOp(waiting.front()->getPriority()))
Scheduler::PKsetPriority(owner,waiting.front()->getPriority());
} else {
- owner=0; //No threads waiting
+ owner=nullptr; //No threads waiting
std::vector<Thread *>().swap(waiting); //Save some RAM
}
@@ -363,27 +365,21 @@ unsigned int Mutex::PKunlockAllDepthLevels(PauseKernelLock& dLock)
// class ConditionVariable
//
-ConditionVariable::ConditionVariable(): first(0), last(0) {}
+//Memory layout must be kept in sync with pthread_cond, see wait(FastMutex& m)
+static_assert(sizeof(ConditionVariable)==sizeof(pthread_cond_t),"");
void ConditionVariable::wait(Mutex& m)
{
PauseKernelLock dLock;
-
- WaitingData w;
- w.p=Thread::getCurrentThread();
- w.next=0;
- //Add entry to tail of list
- if(first==0)
- {
- first=last=&w;
- } else {
- last->next=&w;
- last=&w;
- }
+ Thread *t=Thread::getCurrentThread();
+ CondData listItem;
+ listItem.thread=t;
+ condList.push_back(&listItem); //Add entry to tail of list
+
//Unlock mutex and wait
{
FastInterruptDisableLock l;
- w.p->flags.IRQsetCondWait(true);
+ t->flags.IRQsetCondWait(true);
}
unsigned int depth=m.PKunlockAllDepthLevels(dLock);
@@ -394,30 +390,55 @@ void ConditionVariable::wait(Mutex& m)
m.PKlockToDepth(dLock,depth);
}
-void ConditionVariable::wait(FastMutex& m)
+TimedWaitResult ConditionVariable::timedWait(Mutex& m, long long absTime)
{
- FastInterruptDisableLock dLock;
-
- WaitingData w;
- w.p=Thread::getCurrentThread();
- w.next=0;
- //Add entry to tail of list
- if(first==0)
+ //Disallow absolute sleeps with negative or too low values, as the ns2tick()
+ //algorithm in TimeConversion can't handle negative values and may undeflow
+ //even with very low values due to a negative adjustOffsetNs. As an unlikely
+ //side effect, very shor sleeps done very early at boot will be extended.
+ absTime=std::max(absTime,100000LL);
+
+ PauseKernelLock dLock;
+ Thread *t=Thread::getCurrentThread();
+ CondData listItem;
+ listItem.thread=t;
+ condList.push_back(&listItem); //Add entry to tail of list
+ SleepData sleepData;
+ sleepData.p=t;
+ sleepData.wakeupTime=absTime;
+
+ //Unlock mutex and wait
{
- first=last=&w;
- } else {
- last->next=&w;
- last=&w;
+ FastInterruptDisableLock l;
+ IRQaddToSleepingList(&sleepData); //Putting this thread on the sleeping list too
+ t->flags.IRQsetCondWait(true);
}
- //Unlock mutex and wait
- w.p->flags.IRQsetCondWait(true);
- unsigned int depth=IRQdoMutexUnlockAllDepthLevels(m.get());
+ unsigned int depth=m.PKunlockAllDepthLevels(dLock);
{
- FastInterruptEnableLock eLock(dLock);
+ RestartKernelLock eLock(dLock);
Thread::yield(); //Here the wait becomes effective
}
- IRQdoMutexLockToDepth(m.get(),dLock,depth);
+
+ //Ensure that the thread is removed from both list, as it can be woken by
+ //either a signal/broadcast (that removes it from condList) or by
+ //IRQwakeThreads (that removes it from sleeping list).
+ bool removed=condList.removeFast(&listItem);
+ {
+ FastInterruptDisableLock l;
+ IRQremoveFromSleepingList(&sleepData);
+ }
+
+ m.PKlockToDepth(dLock,depth);
+
+ //If the thread was still in the cond variable list, it was woken up by a timeout
+ return removed ? TimedWaitResult::Timeout : TimedWaitResult::NoTimeout;
+}
+
+TimedWaitResult ConditionVariable::timedWait(FastMutex& m, long long absTime)
+{
+ return pthreadCondTimedWaitImpl(reinterpret_cast<pthread_cond_t*>(this),
+ m.get(),absTime)==ETIMEDOUT ? TimedWaitResult::Timeout : TimedWaitResult::NoTimeout;
}
void ConditionVariable::signal()
@@ -428,14 +449,15 @@ void ConditionVariable::signal()
//that can only be called with irq disabled, othrwise we would use
//PauseKernelLock
FastInterruptDisableLock lock;
- if(first==0) return;
- //Wakeup
- first->p->flags.IRQsetCondWait(false);
+ if(condList.empty()) return;
+ //Remove from list and wakeup
+ Thread *t=condList.front()->thread;
+ condList.pop_front();
+ t->flags.IRQsetCondWait(false);
+ t->flags.IRQsetSleep(false); //Needed due to timedwait
//Check for priority issues
- if(Thread::IRQgetCurrentThread()->IRQgetPriority() <
- first->p->IRQgetPriority()) hppw=true;
- //Remove from list
- first=first->next;
+ if(t->IRQgetPriority()>Thread::IRQgetCurrentThread()->IRQgetPriority())
+ hppw=true;
}
//If the woken thread has higher priority than our priority, yield
if(hppw) Thread::yield();
@@ -449,15 +471,16 @@ void ConditionVariable::broadcast()
//that can only be called with irq disabled, othrwise we would use
//PauseKernelLock
FastInterruptDisableLock lock;
- while(first!=0)
+ while(!condList.empty())
{
- //Wakeup
- first->p->flags.IRQsetCondWait(false);
+ //Remove from list and wakeup
+ Thread *t=condList.front()->thread;
+ condList.pop_front();
+ t->flags.IRQsetCondWait(false);
+ t->flags.IRQsetSleep(false); //Needed due to timedwait
//Check for priority issues
- if(Thread::IRQgetCurrentThread()->IRQgetPriority() <
- first->p->IRQgetPriority()) hppw=true;
- //Remove from list
- first=first->next;
+ if(t->IRQgetPriority()>Thread::IRQgetCurrentThread()->IRQgetPriority())
+ hppw=true;
}
}
//If at least one of the woken thread has higher priority than our priority,
diff --git a/miosix/kernel/sync.h b/miosix/kernel/sync.h
index dfc2fd52..7bb97449 100644
--- a/miosix/kernel/sync.h
+++ b/miosix/kernel/sync.h
@@ -1,6 +1,5 @@
/***************************************************************************
- * Copyright (C) 2008, 2009, 2010, 2011, 2012, 2013, 2014 *
- * by Terraneo Federico *
+ * Copyright (C) 2008-2023 by Terraneo Federico *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
@@ -25,12 +24,11 @@
* You should have received a copy of the GNU General Public License *
* along with this program; if not, see <http://www.gnu.org/licenses/> *
***************************************************************************/
- //Miosix kernel
-#ifndef SYNC_H
-#define SYNC_H
+#pragma once
#include "kernel.h"
+#include "intrusive.h"
#include <vector>
namespace miosix {
@@ -68,7 +66,7 @@ public:
pthread_mutexattr_settype(&temp,PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(&impl,&temp);
pthread_mutexattr_destroy(&temp);
- } else pthread_mutex_init(&impl,NULL);
+ } else pthread_mutex_init(&impl,nullptr);
}
/**
@@ -386,6 +384,26 @@ private:
T& mutex;///< Reference to locked mutex
};
+/**
+ * \internal
+ * \struct CondData
+ * This struct is used to make a list of threads that are waiting on a condition
+ * variable. It is used by the kernel, and should not be used by end users.
+ */
+struct CondData : public IntrusiveListItem
+{
+ Thread *thread; ///<\internal Thread that is waiting
+};
+
+/**
+ * Possible return values of timedWait
+ */
+enum class TimedWaitResult
+{
+ NoTimeout,
+ Timeout
+};
+
/**
* A condition variable class for thread synchronization, available from
* Miosix 1.53.<br>
@@ -402,7 +420,7 @@ public:
/**
* Constructor, initializes the ConditionVariable.
*/
- ConditionVariable();
+ ConditionVariable() {}
/**
* Unlock the mutex and wait.
@@ -416,6 +434,20 @@ public:
wait(l.get());
}
+ /**
+ * Unlock the mutex and wait until woken up or timeout occurs.
+ * If more threads call wait() they must do so specifying the same mutex,
+ * otherwise the behaviour is undefined.
+ * \param l A Lock instance that locked a Mutex
+ * \param absTime absolute timeout time in nanoseconds
+ * \return whether the return was due to a timout or wakeup
+ */
+ template<typename T>
+ TimedWaitResult wait(Lock<T>& l, long long absTime)
+ {
+ return timedWait(l.get());
+ }
+
/**
* Unlock the Mutex and wait.
* If more threads call wait() they must do so specifying the same mutex,
@@ -430,7 +462,32 @@ public:
* otherwise the behaviour is undefined.
* \param m a locked Mutex
*/
- void wait(FastMutex& m);
+ void wait(FastMutex& m)
+ {
+ //Memory layout of ConditionVariable is the same of pthread_cond_t and
+ //the algorithm would be exactly the same
+ pthread_cond_wait(reinterpret_cast<pthread_cond_t*>(this),m.get());
+ }
+
+ /**
+ * Unlock the Mutex and wait until woken up or timeout occurs.
+ * If more threads call wait() they must do so specifying the same mutex,
+ * otherwise the behaviour is undefined.
+ * \param m a locked Mutex
+ * \param absTime absolute timeout time in nanoseconds
+ * \return whether the return was due to a timout or wakeup
+ */
+ TimedWaitResult timedWait(Mutex& m, long long absTime);
+
+ /**
+ * Unlock the FastMutex and wait until woken up or timeout occurs.
+ * If more threads call wait() they must do so specifying the same mutex,
+ * otherwise the behaviour is undefined.
+ * \param m a locked Mutex
+ * \param absTime absolute timeout time in nanoseconds
+ * \return whether the return was due to a timout or wakeup
+ */
+ TimedWaitResult timedWait(FastMutex& m, long long absTime);
/**
* Wakeup one waiting thread.
@@ -448,19 +505,8 @@ private:
ConditionVariable(const ConditionVariable& );
ConditionVariable& operator= (const ConditionVariable& );
- /**
- * \internal
- * \struct WaitingData
- * This struct is used to make a list of waiting threads.
- */
- struct WaitingData
- {
- Thread *p;///<\internal Thread that is waiting
- WaitingData *next;///<\internal Next thread in the list
- };
-
- WaitingData *first;///<Pointer to first element of waiting fifo
- WaitingData *last;///<Pointer to last element of waiting fifo
+ //Memory layout must be kept in sync with pthread_cond, see wait(FastMutex& m)
+ IntrusiveList<CondData> condList;
};
/**
@@ -468,5 +514,3 @@ private:
*/
} //namespace miosix
-
-#endif //SYNC_H
--
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