#include <pthread.h>
#include <pthread_extra.h>
#include <signal.h>
+#include <semaphore.h>
#include <errno.h>
#include <unistd.h>
#include <sys/resource.h>
+//#include <sys/siginfo.h>
//#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
//#include <sys/time.h>
-void pthread_pause_handler() {
- //Do nothing when there are more signals pending (to cleanup the queue)
- sigset_t pending;
- sigpending(&pending);
- if(sigismember(&pending, PTHREAD_XSIG_STOP)) return;
+//Mutex that ensures proper serialization of (un)pause calls
+//pthread_mutex_t pthread_pause_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
+
+//Semaphore that ensures proper serialization of (un)pause signals
+sem_t pthread_pause_sem;
+//Once control to init the semaphore (and possibly other stuff)
+pthread_once_t pthread_pause_once_ctrl = PTHREAD_ONCE_INIT;
+void pthread_pause_once(void) {
+ sem_init(&pthread_pause_sem, 0, 1);
+}
+void pthread_pause_init() { pthread_once(&pthread_pause_once_ctrl, &pthread_pause_once); }
+
+///When this variable is nonzero, only referenced thread is allowed to run
+///Access has to be protected by pthread_user_data_lock() and pthread_pause_sem;
+pthread_t pthread_pause_holder = PTHREAD_XNULL;
+
+void pthread_pause_handler(const int signal, siginfo_t *info, void *ptr) {
+ (void)signal; (void)info; (void)ptr;
+ int run = info->si_value.sival_int;
+ //(void)td;
+
+ //Post semaphore to confirm that signal is handled
+ sem_post(&pthread_pause_sem);
//Keep waiting for signals until we are supposed to be running
- sigset_t sigset;
- sigfillset(&sigset);
- sigdelset(&sigset, PTHREAD_XSIG_STOP);
- if(!pthread_user_data_internal(pthread_self())->running) {
+ if(!run) {
+ sigset_t sigset;
+ sigfillset(&sigset);
+ sigdelset(&sigset, PTHREAD_XSIG_STOP);
sigsuspend(&sigset);
}
}
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:
//grep -i sig /proc/$(pgrep binary)/status
- struct rlimit sigq = {.rlim_cur = 32, .rlim_max=32};
- setrlimit(RLIMIT_SIGPENDING, &sigq);
-
- //Setup signal handler
- signal(PTHREAD_XSIG_STOP, pthread_pause_handler);
+ //struct rlimit sigq = {.rlim_cur = 32, .rlim_max=32};
+ //setrlimit(RLIMIT_SIGPENDING, &sigq);
- //Unblock signal
+ //Prepare signal mask
sigset_t sigset;
sigemptyset(&sigset);
sigaddset(&sigset, PTHREAD_XSIG_STOP);
+
+ //Setup signal handler
+ //signal(PTHREAD_XSIG_STOP, pthread_pause_handler);
+ const struct sigaction pause_sa = {
+ .sa_sigaction = pthread_pause_handler,
+ .sa_mask = sigset,
+ .sa_flags = SA_SIGINFO | SA_RESTART,
+ .sa_restorer = NULL
+ };
+
+ sigaction(PTHREAD_XSIG_STOP, &pause_sa, NULL);
+
+ //Unblock signal
pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);
+
+ //Add thread to internal registry
+ 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());
+ //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
+ //Maybe not a good idea, causes DEADLOCKS!
+ //sem_wait(&pthread_pause_sem);
pthread_sigmask(SIG_BLOCK, &sigset, NULL);
+ //sem_post(&pthread_pause_sem);
+
+ //pthread_user_data_unlock();
}
+/*
int pthread_pause_reschedule(pthread_t thread) {
//Send signal to initiate pause handler
- while(pthread_kill(thread, PTHREAD_XSIG_STOP) == EAGAIN) usleep(1000);
+ //printf("SND: %p\n", (void *)pthread_user_data_internal(thread));
+ //while(pthread_kill(thread, PTHREAD_XSIG_STOP) == EAGAIN) usleep(1000);
+ while(pthread_sigqueue(thread, PTHREAD_XSIG_STOP,
+ (const union sigval){.sival_ptr=pthread_user_data_internal(thread)}
+ ) == EAGAIN) usleep(1000);
return 0;
}
+*/
+
+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);
+
+ //Only call this if you already acquired pthread_pause_sem semaphore!!!!
+ //Otherwise call pthread_pause_reschedule()
+
+ //Check if thread has running flag
+ int run = (pthread_user_data_internal(thread)->running);
+ //Check if privileged (single thread) mode is active
+ if(!pthread_equal(pthread_pause_holder, PTHREAD_XNULL) && !pthread_equal(pthread_pause_holder, thread)) {
+ run = 0;
+ }
+
+ //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);
+
+ //Wait for signal to be delivered
+ sem_wait(&pthread_pause_sem);
+ sem_post(&pthread_pause_sem);
+ pthread_user_data_unlock();
+
+ return 0;
+}
+
+int pthread_extra_yield() {
+ //Yield to both schedulers
+ pthread_pause_reschedule(pthread_self());
+ 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) {
+ 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) {
+ 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();
+ //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();
+ //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;
+}
// Wrappers ///////////////////////////////////////////////////////////
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());
//Check if we should be running according to pthread_pause sub-scheduler
- pthread_pause_reschedule(pthread_self());
+ //pthread_pause_reschedule(pthread_self());
+ pthread_extra_yield();
+ //Run actual task
return task.start_routine(task.arg);
pthread_cleanup_pop(1); //Needed by pthread_cleanup_push() macro
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