X-Git-Url: https://git.harvie.cz/?a=blobdiff_plain;f=c%2Fpthread_extra%2Fpthread_pause.c;h=950d6fa26954ffdbf5d42ad9fcec3a27fd3e860b;hb=30d358cd5a66ea85b06729df8fa13a068ac21d51;hp=a9ce5dce3c487e87613fff24d90c39fe045f5741;hpb=3109d0d18e330e166a45042a2d363ec1b285c493;p=mirrors%2FPrograms.git

diff --git a/c/pthread_extra/pthread_pause.c b/c/pthread_extra/pthread_pause.c
index a9ce5dc..950d6fa 100644
--- a/c/pthread_extra/pthread_pause.c
+++ b/c/pthread_extra/pthread_pause.c
@@ -47,8 +47,7 @@ void pthread_pause_handler(const int signal, siginfo_t *info, void *ptr) {
 }
 
 void pthread_pause_enable() {
-	//Add thread to internal registry
-	//pthread_user_data_internal(pthread_self());
+	pthread_pause_init(); //Make sure semaphore is init'd
 
 	//Nesting signals too deep is not good for stack
 	//You can get runtime stats using following command:
@@ -56,8 +55,6 @@ void pthread_pause_enable() {
 	//struct rlimit sigq = {.rlim_cur = 32, .rlim_max=32};
 	//setrlimit(RLIMIT_SIGPENDING, &sigq);
 
-	pthread_pause_init(); //Make sure semaphore is init'd
-
 	//Prepare signal mask
 	sigset_t sigset;
 	sigemptyset(&sigset);
@@ -71,27 +68,35 @@ void pthread_pause_enable() {
 		.sa_flags = SA_SIGINFO | SA_RESTART,
 		.sa_restorer = NULL
 	};
+
 	sigaction(PTHREAD_XSIG_STOP, &pause_sa, NULL);
 
 	//Unblock signal
 	pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);
-}
 
-void pthread_pause_disable() {
 	//Add thread to internal registry
-	//pthread_user_data_internal(pthread_self());
+	pthread_user_data_internal(pthread_self()); //Only now, when signals are unblocked!
+}
 
+void pthread_pause_disable() {
+	//pthread_user_data_lock();
 	pthread_pause_init(); //Make sure semaphore is init'd
 
+	//Add thread to internal registry
+	//pthread_user_data_internal(pthread_self()); //DEADLOCKS!
+
 	//Block signal
 	sigset_t sigset;
 	sigemptyset(&sigset);
 	sigaddset(&sigset, PTHREAD_XSIG_STOP);
 
 	//Make sure all signals are dispatched before we block them
-	sem_wait(&pthread_pause_sem);
+	//Maybe not a good idea, causes DEADLOCKS!
+	//sem_wait(&pthread_pause_sem);
 	pthread_sigmask(SIG_BLOCK, &sigset, NULL);
-	sem_post(&pthread_pause_sem);
+	//sem_post(&pthread_pause_sem);
+
+	//pthread_user_data_unlock();
 }
 
 /*
@@ -108,6 +113,7 @@ int pthread_pause_reschedule(pthread_t thread) {
 
 int pthread_pause_reschedule(pthread_t thread) {
 	//Decide if the thread should run and signal it
+	pthread_user_data_lock();
 
 	//Wait for semaphore which means signal queue is empty
 	pthread_pause_init(); //Make sure semaphore is init'd
@@ -116,17 +122,16 @@ int pthread_pause_reschedule(pthread_t thread) {
 	//Only call this if you already acquired pthread_pause_sem semaphore!!!!
 	//Otherwise call pthread_pause_reschedule()
 
-	pthread_user_data_lock();
 	//Check if thread has running flag
 	int run = (pthread_user_data_internal(thread)->running);
 	//Check if privileged (single thread) mode is active
-	if((pthread_pause_holder != PTHREAD_XNULL) && !pthread_equal(pthread_pause_holder, thread)) {
+	if(!pthread_equal(pthread_pause_holder, PTHREAD_XNULL) && !pthread_equal(pthread_pause_holder, thread)) {
 		run = 0;
 	}
-	pthread_user_data_unlock();
 
 	//Send signal to initiate pause handler (keep trying while SigQueue is full)
 	//while(pthread_kill(thread, PTHREAD_XSIG_STOP) == EAGAIN) usleep(1000);
+	//printf("Sched %lu = %d (self: %lu, lck: %lu)\n", thread, run, pthread_self(), pthread_pause_holder);
 	while(pthread_sigqueue(thread, PTHREAD_XSIG_STOP,
 		(const union sigval){.sival_int=run}
 		) == EAGAIN) usleep(1000);
@@ -134,6 +139,7 @@ int pthread_pause_reschedule(pthread_t thread) {
 	//Wait for signal to be delivered
 	sem_wait(&pthread_pause_sem);
 	sem_post(&pthread_pause_sem);
+	pthread_user_data_unlock();
 
 	return 0;
 }
@@ -144,38 +150,58 @@ int pthread_extra_yield() {
 	return pthread_yield();
 }
 
+///Sanity check to be sure there are no race conditions
+inline void pthread_pause_assert_owner() {
+	if(!pthread_equal(pthread_pause_holder,PTHREAD_XNULL))
+		assert(pthread_equal(pthread_pause_holder, pthread_self()));
+}
+
+///Pause specified thread (block until it is paused)
 int pthread_pause(pthread_t thread) {
-	//Set thread as paused and notify it via signal (wait when queue full)
 	pthread_user_data_lock();
+	pthread_pause_assert_owner();
+	//if(!pthread_equal(pthread_pause_holder,PTHREAD_XNULL)) assert(pthread_equal(pthread_pause_holder, pthread_self()));
+	//Set thread as paused and notify it via signal (wait when queue full)
 	pthread_user_data_internal(thread)->running = 0;
 	pthread_pause_reschedule(thread);
 	pthread_user_data_unlock();
 	return 0;
 }
 
+///UnPause specified thread (block until it is unpaused)
 int pthread_unpause(pthread_t thread) {
-	//Set thread as running and notify it via signal (wait when queue full)
 	pthread_user_data_lock();
+	pthread_pause_assert_owner();
+	//Set thread as running and notify it via signal (wait when queue full)
 	pthread_user_data_internal(thread)->running = 1;
 	pthread_pause_reschedule(thread);
 	pthread_user_data_unlock();
 	return 0;
 }
 
+///Enter exclusive mode by pausing everyone else
 int pthread_pause_all() {
+	//printf("Pause ALL\n");
 	pthread_user_data_lock();
-	if(pthread_pause_holder!=PTHREAD_XNULL) assert(pthread_equal(pthread_pause_holder, pthread_self()));
+	//printf("Pause ALL+\n");
+	//printf("Pause %p == %p\n", (void *)pthread_pause_holder, (void *)pthread_self());
+	pthread_pause_assert_owner();
 	pthread_pause_holder = pthread_self();
 	pthread_user_data_internal_iterate(&pthread_pause_reschedule, NULL);
+	//printf("Pause ALL!\n");
 	pthread_user_data_unlock();
 	return 0;
 }
 
+///Leave exclusive mode by unpausing everyone else
 int pthread_unpause_all() {
+	//printf("UnPause ALL\n");
 	pthread_user_data_lock();
-	if(pthread_pause_holder!=PTHREAD_XNULL) assert(pthread_equal(pthread_pause_holder, pthread_self()));
+	//printf("UnPause ALL+\n");
+	pthread_pause_assert_owner();
 	pthread_pause_holder = PTHREAD_XNULL;
 	pthread_user_data_internal_iterate(&pthread_pause_reschedule, NULL);
+	//printf("UnPause ALL!\n");
 	pthread_user_data_unlock();
 	return 0;
 }
@@ -193,8 +219,10 @@ void *pthread_extra_thread_wrapper(void *arg) {
 	pthread_extra_wrapper_t task = *((pthread_extra_wrapper_t*)arg);
 	free(arg);
 
+	pthread_pause_enable();
+
 	//Register new thread to user data structure
-	pthread_user_data_internal(pthread_self());
+	//pthread_user_data_internal(pthread_self()); //Perhaps already done in pthread_extra_yield() and pthread_pause_enable()??
 
 	//TODO: user_data should do this automaticaly?
 	pthread_cleanup_push(pthread_user_data_cleanup, (void *)pthread_self());