Exclusive mode seems to work without deadlocks

[mirrors/Programs.git] / c / pthread_extra / pthread_pause.c

diff --git a/c/pthread_extra/pthread_pause.c b/c/pthread_extra/pthread_pause.c
index a9ce5dce3c487e87613fff24d90c39fe045f5741..24521af71f38741c0e85ea04412f89724f173626 100644 (file)
--- a/c/pthread_extra/pthread_pause.c
+++ b/c/pthread_extra/pthread_pause.c
@@ -47,8 +47,10 @@ void pthread_pause_handler(const int signal, siginfo_t *info, void *ptr) {
 }
 
 void pthread_pause_enable() {
+       pthread_pause_init(); //Make sure semaphore is init'd
+
        //Add thread to internal registry
-       //pthread_user_data_internal(pthread_self());
+       pthread_user_data_internal(pthread_self());
 
        //Nesting signals too deep is not good for stack
        //You can get runtime stats using following command:
@@ -56,8 +58,6 @@ 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);
@@ -78,11 +78,11 @@ void pthread_pause_enable() {
 }
 
 void pthread_pause_disable() {
-       //Add thread to internal registry
-       //pthread_user_data_internal(pthread_self());
-
        pthread_pause_init(); //Make sure semaphore is init'd
 
+       //Add thread to internal registry
+       pthread_user_data_internal(pthread_self());
+
        //Block signal
        sigset_t sigset;
        sigemptyset(&sigset);
@@ -109,6 +109,8 @@ 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
        sem_wait(&pthread_pause_sem);
@@ -116,17 +118,16 @@ 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 +135,7 @@ 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;
 }
@@ -162,20 +164,29 @@ int pthread_unpause(pthread_t thread) {
        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());
+       if(!pthread_equal(pthread_pause_holder,PTHREAD_XNULL)) assert(pthread_equal(pthread_pause_holder, pthread_self()));
        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");
+       if(!pthread_equal(pthread_pause_holder,PTHREAD_XNULL)) assert(pthread_equal(pthread_pause_holder, pthread_self()));
        pthread_pause_holder = PTHREAD_XNULL;
        pthread_user_data_internal_iterate(&pthread_pause_reschedule, NULL);
+       //printf("UnPause ALL!\n");
        pthread_user_data_unlock();
        return 0;
 }
@@ -194,7 +205,7 @@ void *pthread_extra_thread_wrapper(void *arg) {
        free(arg);
 
        //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()??
 
        //TODO: user_data should do this automaticaly?
        pthread_cleanup_push(pthread_user_data_cleanup, (void *)pthread_self());