4 * Citadel "system dependent" stuff.
5 * See COPYING for copyright information.
7 * Here's where we have the Citadel thread implimentation
14 #include <sys/types.h>
16 #include <sys/socket.h>
22 #if TIME_WITH_SYS_TIME
23 # include <sys/time.h>
27 # include <sys/time.h>
36 # if HAVE_SYS_SYSCALL_H
37 # include <sys/syscall.h>
41 #include <libcitadel.h>
44 #include "ctdl_module.h"
45 #include "modules_init.h"
46 #include "housekeeping.h"
48 #include "citserver.h"
49 #include "sysdep_decls.h"
53 * define this to use the new worker_thread method of handling connections
58 * New thread interface.
59 * To create a thread you must call one of the create thread functions.
60 * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
61 * struct CtdlThreadNode *node = NULL;
63 * If the thread is created *node will point to the thread control structure for the created thread.
64 * If the thread creation fails *node remains NULL
65 * Do not free the memory pointed to by *node, it doesn't belong to you.
66 * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
67 * remove the need for the calls to eCrashRegisterThread and friends
70 static int num_threads = 0; /* Current number of threads */
71 static int num_workers = 0; /* Current number of worker threads */
72 long statcount = 0; /* are we doing a stats check? */
73 static long stats_done = 0;
75 CtdlThreadNode *CtdlThreadList = NULL;
76 CtdlThreadNode *CtdlThreadSchedList = NULL;
78 static CtdlThreadNode *GC_thread = NULL;
79 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
80 double CtdlThreadLoadAvg = 0;
81 double CtdlThreadWorkerAvg = 0;
82 citthread_key_t ThreadKey;
84 citthread_mutex_t Critters[MAX_SEMAPHORES]; /* Things needing locking */
88 void InitialiseSemaphores(void)
92 /* Set up a bunch of semaphores to be used for critical sections */
93 for (i=0; i<MAX_SEMAPHORES; ++i) {
94 citthread_mutex_init(&Critters[i], NULL);
102 * Obtain a semaphore lock to begin a critical section.
103 * but only if no one else has one
105 int try_critical_section(int which_one)
107 /* For all types of critical sections except those listed here,
108 * ensure nobody ever tries to do a critical section within a
109 * transaction; this could lead to deadlock.
111 if ( (which_one != S_FLOORCACHE)
112 #ifdef DEBUG_MEMORY_LEAKS
113 && (which_one != S_DEBUGMEMLEAKS)
115 && (which_one != S_RPLIST)
119 return (citthread_mutex_trylock(&Critters[which_one]));
124 * Obtain a semaphore lock to begin a critical section.
126 void begin_critical_section(int which_one)
128 /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
130 /* For all types of critical sections except those listed here,
131 * ensure nobody ever tries to do a critical section within a
132 * transaction; this could lead to deadlock.
134 if ( (which_one != S_FLOORCACHE)
135 #ifdef DEBUG_MEMORY_LEAKS
136 && (which_one != S_DEBUGMEMLEAKS)
138 && (which_one != S_RPLIST)
142 citthread_mutex_lock(&Critters[which_one]);
146 * Release a semaphore lock to end a critical section.
148 void end_critical_section(int which_one)
150 citthread_mutex_unlock(&Critters[which_one]);
155 * A function to destroy the TSD
157 static void ctdl_thread_internal_dest_tsd(void *arg)
167 * A function to initialise the thread TSD
169 void ctdl_thread_internal_init_tsd(void)
173 if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
174 CtdlLogPrintf(CTDL_EMERG, "citthread_key_create: %s\n", strerror(ret));
180 * Ensure that we have a key for thread-specific data.
182 * This should be called immediately after startup by any thread
185 void CtdlThreadAllocTSD(void)
189 if (citthread_getspecific(ThreadKey) != NULL)
192 tsd = malloc(sizeof(ThreadTSD));
196 memset(tsd->cursors, 0, sizeof tsd->cursors);
199 citthread_setspecific(ThreadKey, tsd);
203 void ctdl_thread_internal_free_tsd(void)
205 ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
206 citthread_setspecific(ThreadKey, NULL);
210 void ctdl_thread_internal_cleanup(void)
213 CtdlThreadNode *this_thread, *that_thread;
215 for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
217 free (CtdlThreadStates[i]);
220 /* Clean up the scheduled thread list */
221 this_thread = CtdlThreadSchedList;
224 that_thread = this_thread;
225 this_thread = this_thread->next;
226 citthread_mutex_destroy(&that_thread->ThreadMutex);
227 citthread_cond_destroy(&that_thread->ThreadCond);
228 citthread_mutex_destroy(&that_thread->SleepMutex);
229 citthread_cond_destroy(&that_thread->SleepCond);
230 citthread_attr_destroy(&that_thread->attr);
233 ctdl_thread_internal_free_tsd();
236 void ctdl_thread_internal_init(void)
238 CtdlThreadNode *this_thread;
241 CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
242 CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
243 CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
244 CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
245 CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
246 CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
247 CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
248 CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
249 CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
250 CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
252 /* Get ourself a thread entry */
253 this_thread = malloc(sizeof(CtdlThreadNode));
254 if (this_thread == NULL) {
255 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
258 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
259 memset (this_thread, 0, sizeof(CtdlThreadNode));
261 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
262 citthread_cond_init (&(this_thread->ThreadCond), NULL);
263 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
264 citthread_cond_init (&(this_thread->SleepCond), NULL);
266 /* We are garbage collector so create us as running */
267 this_thread->state = CTDL_THREAD_RUNNING;
269 if ((ret = citthread_attr_init(&this_thread->attr))) {
270 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
275 this_thread->name = "Garbage Collection Thread";
277 this_thread->tid = citthread_self();
278 GC_thread = this_thread;
281 num_threads++; // Increase the count of threads in the system.
283 this_thread->next = CtdlThreadList;
284 CtdlThreadList = this_thread;
285 if (this_thread->next)
286 this_thread->next->prev = this_thread;
287 /* Set up start times */
288 gettimeofday(&this_thread->start_time, NULL); /* Time this thread started */
289 memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval)); /* Changed state so mark it. */
294 * A function to update a threads load averages
296 void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
298 struct timeval now, result;
299 double last_duration;
301 gettimeofday(&now, NULL);
302 timersub(&now, &(this_thread->last_state_change), &result);
303 /* I don't think these mutex's are needed here */
304 citthread_mutex_lock(&this_thread->ThreadMutex);
305 // result now has a timeval for the time we spent in the last state since we last updated
306 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
307 if (this_thread->state == CTDL_THREAD_SLEEPING)
308 this_thread->avg_sleeping += last_duration;
309 if (this_thread->state == CTDL_THREAD_RUNNING)
310 this_thread->avg_running += last_duration;
311 if (this_thread->state == CTDL_THREAD_BLOCKED)
312 this_thread->avg_blocked += last_duration;
313 memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
314 citthread_mutex_unlock(&this_thread->ThreadMutex);
318 * A function to chenge the state of a thread
320 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
323 * Wether we change state or not we need update the load values
325 ctdl_thread_internal_update_avgs(this_thread);
326 /* This mutex not needed here? */
327 citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
328 if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
329 this_thread->state = new_state;
330 if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
331 this_thread->state = new_state;
332 if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
333 this_thread->state = new_state;
334 citthread_mutex_unlock(&this_thread->ThreadMutex);
339 * A function to tell all threads to exit
341 void CtdlThreadStopAll(void)
343 /* First run any registered shutdown hooks. This probably doesn't belong here. */
344 PerformSessionHooks(EVT_SHUTDOWN);
346 //FIXME: The signalling of the condition should not be in the critical_section
347 // We need to build a list of threads we are going to signal and then signal them afterwards
349 CtdlThreadNode *this_thread;
351 begin_critical_section(S_THREAD_LIST);
352 this_thread = CtdlThreadList;
353 // Ask the GC thread to stop first so everything knows we are shutting down.
354 GC_thread->state = CTDL_THREAD_STOP_REQ;
357 if (!citthread_equal(this_thread->tid, GC_thread->tid))
358 citthread_kill(this_thread->tid, SIGHUP);
360 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
361 citthread_cond_signal(&this_thread->ThreadCond);
362 citthread_cond_signal(&this_thread->SleepCond);
363 this_thread->stop_ticker = time(NULL);
364 CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
365 this_thread->name, this_thread->tid);
366 this_thread = this_thread->next;
368 end_critical_section(S_THREAD_LIST);
373 * A function to wake up all sleeping threads
375 void CtdlThreadWakeAll(void)
377 CtdlThreadNode *this_thread;
379 CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
381 begin_critical_section(S_THREAD_LIST);
382 this_thread = CtdlThreadList;
385 if (!this_thread->thread_func)
387 citthread_cond_signal(&this_thread->ThreadCond);
388 citthread_cond_signal(&this_thread->SleepCond);
390 this_thread = this_thread->next;
392 end_critical_section(S_THREAD_LIST);
397 * A function to return the number of threads running in the system
399 int CtdlThreadGetCount(void)
404 int CtdlThreadGetWorkers(void)
409 double CtdlThreadGetWorkerAvg(void)
413 begin_critical_section(S_THREAD_LIST);
414 ret = CtdlThreadWorkerAvg;
415 end_critical_section(S_THREAD_LIST);
419 double CtdlThreadGetLoadAvg(void)
421 double load_avg[3] = {0.0, 0.0, 0.0};
426 /* Borrowed this straight from procps */
427 smp_num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
428 if(smp_num_cpus<1) smp_num_cpus=1; /* SPARC glibc is buggy */
430 #ifdef HAVE_GETLOADAVG
431 ret = getloadavg(load_avg, 3);
435 return load_avg[0] / smp_num_cpus;
437 * This old chunk of code return a value that indicated the load on citserver
438 * This value could easily reach 100 % even when citserver was doing very little and
439 * hence the machine has much more spare capacity.
440 * Because this value was used to determine if the machine was under heavy load conditions
441 * from other processes in the system then citserver could be strangled un-necesarily
442 * What we are actually trying to achieve is to strangle citserver if the machine is heavily loaded.
443 * So we have changed this.
445 begin_critical_section(S_THREAD_LIST);
446 ret = CtdlThreadLoadAvg;
447 end_critical_section(S_THREAD_LIST);
456 * A function to rename a thread
457 * Returns a const char *
459 const char *CtdlThreadName(const char *name)
461 const char *old_name;
465 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
476 * A function to force a thread to exit
478 void CtdlThreadCancel(CtdlThreadNode *thread)
480 CtdlThreadNode *this_thread;
485 this_thread = thread;
488 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
493 if (!this_thread->thread_func)
495 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
500 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
501 citthread_cancel(this_thread->tid);
506 * A function for a thread to check if it has been asked to stop
508 int CtdlThreadCheckStop(void)
514 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
523 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
524 if (CT->signal == SIGHUP)
525 CT->state = CTDL_THREAD_STOP_REQ;
528 if(state == CTDL_THREAD_STOP_REQ)
530 CT->state = CTDL_THREAD_STOPPING;
533 else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
542 * A function to ask a thread to exit
543 * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
545 void CtdlThreadStop(CtdlThreadNode *thread)
547 CtdlThreadNode *this_thread;
552 this_thread = thread;
555 if (!(this_thread->thread_func))
556 return; // Don't stop garbage collector
558 if (!citthread_equal(this_thread->tid, GC_thread->tid))
559 citthread_kill(this_thread->tid, SIGHUP);
561 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
562 citthread_cond_signal(&this_thread->ThreadCond);
563 citthread_cond_signal(&this_thread->SleepCond);
564 this_thread->stop_ticker = time(NULL);
568 * So we now have a sleep command that works with threads but it is in seconds
570 void CtdlThreadSleep(int secs)
572 struct timespec wake_time;
573 struct timeval time_now;
578 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
582 memset (&wake_time, 0, sizeof(struct timespec));
583 gettimeofday(&time_now, NULL);
584 wake_time.tv_sec = time_now.tv_sec + secs;
585 wake_time.tv_nsec = time_now.tv_usec * 10;
587 ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
589 citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
590 citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
591 citthread_mutex_unlock(&CT->ThreadMutex);
593 ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
598 * Routine to clean up our thread function on exit
600 static void ctdl_internal_thread_cleanup(void *arg)
603 * In here we were called by the current thread because it is exiting
604 * NB. WE ARE THE CURRENT THREAD
608 const char *name = CT->name;
609 const pid_t tid = CT->tid;
611 CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (0x%08lx) exited.\n", name, tid);
615 CtdlLogPrintf(CTDL_NOTICE, "some ((unknown ? ? ?) Thread exited.\n");
618 #ifdef HAVE_BACKTRACE
619 /// eCrash_UnregisterThread();
622 citthread_mutex_lock(&CT->ThreadMutex);
623 CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
624 citthread_mutex_unlock(&CT->ThreadMutex);
628 * A quick function to show the load averages
630 void ctdl_thread_internal_calc_loadavg(void)
632 CtdlThreadNode *that_thread;
633 double load_avg, worker_avg;
636 that_thread = CtdlThreadList;
641 /* Update load averages */
642 ctdl_thread_internal_update_avgs(that_thread);
643 citthread_mutex_lock(&that_thread->ThreadMutex);
644 that_thread->load_avg = (that_thread->avg_sleeping + that_thread->avg_running) / (that_thread->avg_sleeping + that_thread->avg_running + that_thread->avg_blocked) * 100;
645 that_thread->avg_sleeping /= 2;
646 that_thread->avg_running /= 2;
647 that_thread->avg_blocked /= 2;
648 load_avg += that_thread->load_avg;
649 if (that_thread->flags & CTDLTHREAD_WORKER)
651 worker_avg += that_thread->load_avg;
654 #ifdef WITH_THREADLOG
655 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
658 CtdlThreadStates[that_thread->state],
659 that_thread->avg_sleeping,
660 that_thread->avg_running,
661 that_thread->avg_blocked,
662 that_thread->load_avg);
664 citthread_mutex_unlock(&that_thread->ThreadMutex);
665 that_thread = that_thread->next;
667 CtdlThreadLoadAvg = load_avg/num_threads;
668 CtdlThreadWorkerAvg = worker_avg/workers;
669 #ifdef WITH_THREADLOG
670 CtdlLogPrintf(CTDL_INFO, "System load average %.2f, workers averag %.2f, threads %d, workers %d, sessions %d\n", CtdlThreadGetLoadAvg(), CtdlThreadWorkerAvg, num_threads, num_workers, num_sessions);
676 * Garbage collection routine.
677 * Gets called by main() in a loop to clean up the thread list periodically.
679 void CtdlThreadGC (void)
681 CtdlThreadNode *this_thread, *that_thread;
682 int workers = 0, sys_workers;
685 begin_critical_section(S_THREAD_LIST);
687 /* Handle exiting of garbage collector thread */
689 CtdlThreadList->state = CTDL_THREAD_EXITED;
691 #ifdef WITH_THREADLOG
692 CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
695 * Woke up to do garbage collection
697 this_thread = CtdlThreadList;
700 that_thread = this_thread;
701 this_thread = this_thread->next;
703 if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
704 && (!citthread_equal(that_thread->tid, citthread_self())))
705 CtdlLogPrintf(CTDL_DEBUG, "Waiting for thread %s (0x%08lx) to exit.\n", that_thread->name, that_thread->tid);
709 * Catch the situation where a worker was asked to stop but couldn't and we are not
712 that_thread->stop_ticker = 0;
715 if (that_thread->stop_ticker + 5 == time(NULL))
717 CtdlLogPrintf(CTDL_DEBUG, "Thread System: The thread \"%s\" (0x%08lx) failed to self terminate within 5 ticks. It would be cancelled now.\n", that_thread->name, that_thread->tid);
718 if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
719 CtdlLogPrintf(CTDL_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
720 // that_thread->state = CTDL_THREAD_CANCELLED;
721 that_thread->stop_ticker++;
722 // citthread_cancel(that_thread->tid);
726 /* Do we need to clean up this thread? */
727 if ((that_thread->state != CTDL_THREAD_EXITED) && (that_thread->state != CTDL_THREAD_CANCELLED))
729 if(that_thread->flags & CTDLTHREAD_WORKER)
730 workers++; /* Sanity check on number of worker threads */
734 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
736 end_critical_section(S_THREAD_LIST);
737 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
742 if (num_threads <= 0)
744 end_critical_section(S_THREAD_LIST);
745 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
750 if(that_thread->flags & CTDLTHREAD_WORKER)
751 num_workers--; /* This is a wroker thread so reduce the count. */
753 /* If we are unlinking the list head then the next becomes the list head */
754 if(that_thread->prev)
755 that_thread->prev->next = that_thread->next;
757 CtdlThreadList = that_thread->next;
758 if(that_thread->next)
759 that_thread->next->prev = that_thread->prev;
761 citthread_cond_signal(&that_thread->ThreadCond);
762 citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
763 citthread_mutex_lock(&that_thread->ThreadMutex); // Make sure it has done what its doing
764 citthread_mutex_unlock(&that_thread->ThreadMutex);
766 * Join on the thread to do clean up and prevent memory leaks
767 * Also makes sure the thread has cleaned up after itself before we remove it from the list
768 * We can join on the garbage collector thread the join should just return EDEADLCK
770 ret = citthread_join (that_thread->tid, NULL);
772 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
773 else if (ret == EINVAL)
774 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
775 else if (ret == ESRCH)
776 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
778 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, citthread_join returned an unknown error(%d).\n", ret);
780 * Now we own that thread entry
782 CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (0x%08lx).\n",
783 that_thread->name, that_thread->tid);
784 citthread_mutex_destroy(&that_thread->ThreadMutex);
785 citthread_cond_destroy(&that_thread->ThreadCond);
786 citthread_mutex_destroy(&that_thread->SleepMutex);
787 citthread_cond_destroy(&that_thread->SleepCond);
788 citthread_attr_destroy(&that_thread->attr);
791 sys_workers = num_workers;
792 end_critical_section(S_THREAD_LIST);
794 /* Sanity check number of worker threads */
795 if (workers != sys_workers)
797 CtdlLogPrintf(CTDL_EMERG,
798 "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
809 * Runtime function for a Citadel Thread.
810 * This initialises the threads environment and then calls the user supplied thread function
811 * Note that this is the REAL thread function and wraps the users thread function.
813 static void *ctdl_internal_thread_func (void *arg)
815 CtdlThreadNode *this_thread;
818 /* lock and unlock the thread list.
819 * This causes this thread to wait until all its creation stuff has finished before it
820 * can continue its execution.
822 begin_critical_section(S_THREAD_LIST);
823 this_thread = (CtdlThreadNode *) arg;
824 gettimeofday(&this_thread->start_time, NULL); /* Time this thread started */
826 // Register the cleanup function to take care of when we exit.
827 citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
828 // Get our thread data structure
829 CtdlThreadAllocTSD();
831 this_thread->pid = getpid();
832 memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval)); /* Changed state so mark it. */
833 /* Only change to running state if we weren't asked to stop during the create cycle
834 * Other wise there is a window to allow this threads creation to continue to full grown and
835 * therby prevent a shutdown of the server.
837 if (!CtdlThreadCheckStop())
839 citthread_mutex_lock(&this_thread->ThreadMutex);
840 this_thread->state = CTDL_THREAD_RUNNING;
841 citthread_mutex_unlock(&this_thread->ThreadMutex);
843 end_critical_section(S_THREAD_LIST);
845 // Register for tracing
846 #ifdef HAVE_BACKTRACE
847 /// eCrash_RegisterThread(this_thread->name, 0);
850 // Tell the world we are here
851 #if defined(HAVE_SYSCALL_H) && defined (SYS_gettid)
852 this_thread->reltid = syscall(SYS_gettid);
854 CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (0x%08lx).\n",
855 this_thread->name, this_thread->tid);
858 * run the thread to do the work but only if we haven't been asked to stop
860 if (!CtdlThreadCheckStop())
861 ret = (this_thread->thread_func)(this_thread->user_args);
864 * Our thread is exiting either because it wanted to end or because the server is stopping
865 * We need to clean up
867 citthread_cleanup_pop(1); // Execute our cleanup routine and remove it
876 * Function to initialise an empty thread structure
878 CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
882 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
883 memset (this_thread, 0, sizeof(CtdlThreadNode));
885 /* Create the mutex's early so we can use them */
886 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
887 citthread_cond_init (&(this_thread->ThreadCond), NULL);
888 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
889 citthread_cond_init (&(this_thread->SleepCond), NULL);
891 this_thread->state = CTDL_THREAD_CREATE;
893 if ((ret = citthread_attr_init(&this_thread->attr))) {
894 citthread_mutex_unlock(&this_thread->ThreadMutex);
895 citthread_mutex_destroy(&(this_thread->ThreadMutex));
896 citthread_cond_destroy(&(this_thread->ThreadCond));
897 citthread_mutex_destroy(&(this_thread->SleepMutex));
898 citthread_cond_destroy(&(this_thread->SleepCond));
899 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
904 /* Our per-thread stacks need to be bigger than the default size,
905 * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
906 * crashes on 64-bit Linux.
908 if (flags & CTDLTHREAD_BIGSTACK)
910 #ifdef WITH_THREADLOG
911 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
913 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
914 citthread_mutex_unlock(&this_thread->ThreadMutex);
915 citthread_mutex_destroy(&(this_thread->ThreadMutex));
916 citthread_cond_destroy(&(this_thread->ThreadCond));
917 citthread_mutex_destroy(&(this_thread->SleepMutex));
918 citthread_cond_destroy(&(this_thread->SleepCond));
919 citthread_attr_destroy(&this_thread->attr);
920 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
927 /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
928 * load average for the system. If we don't do this then we create a mass of threads at the same time
929 * because the creation didn't affect the load average.
931 this_thread->avg_blocked = 2;
933 return (this_thread);
940 * Internal function to create a thread.
942 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
945 CtdlThreadNode *this_thread;
947 if (num_threads >= 32767)
949 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
953 this_thread = malloc(sizeof(CtdlThreadNode));
954 if (this_thread == NULL) {
955 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
959 /* Initialise the thread structure */
960 if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
963 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
967 * If we got here we are going to create the thread so we must initilise the structure
968 * first because most implimentations of threading can't create it in a stopped state
969 * and it might want to do things with its structure that aren't initialised otherwise.
973 this_thread->name = name;
977 this_thread->name = "Un-named Thread";
980 this_thread->flags = flags;
981 this_thread->thread_func = thread_func;
982 this_thread->user_args = args;
984 begin_critical_section(S_THREAD_LIST);
986 * We pass this_thread into the thread as its args so that it can find out information
987 * about itself and it has a bit of storage space for itself, not to mention that the REAL
988 * thread function needs to finish off the setup of the structure
990 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
992 end_critical_section(S_THREAD_LIST);
993 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
995 citthread_mutex_unlock(&this_thread->ThreadMutex);
996 citthread_mutex_destroy(&(this_thread->ThreadMutex));
997 citthread_cond_destroy(&(this_thread->ThreadCond));
998 citthread_mutex_destroy(&(this_thread->SleepMutex));
999 citthread_cond_destroy(&(this_thread->SleepCond));
1000 citthread_attr_destroy(&this_thread->attr);
1004 num_threads++; // Increase the count of threads in the system.
1005 if(this_thread->flags & CTDLTHREAD_WORKER)
1008 this_thread->next = CtdlThreadList;
1009 CtdlThreadList = this_thread;
1010 if (this_thread->next)
1011 this_thread->next->prev = this_thread;
1012 ctdl_thread_internal_calc_loadavg();
1014 end_critical_section(S_THREAD_LIST);
1020 * Wrapper function to create a thread
1021 * ensures the critical section and other protections are in place.
1022 * char *name = name to give to thread, if NULL, use generic name
1023 * int flags = flags to determine type of thread and standard facilities
1025 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
1027 CtdlThreadNode *ret = NULL;
1029 ret = ctdl_internal_create_thread(name, flags, thread_func, args);
1036 * Internal function to schedule a thread.
1037 * Must be called from within a S_THREAD_LIST critical section
1039 CtdlThreadNode *CtdlThreadSchedule(char *name, long flags, void *(*thread_func) (void *arg), void *args, time_t when)
1041 CtdlThreadNode *this_thread;
1043 if (num_threads >= 32767)
1045 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
1049 this_thread = malloc(sizeof(CtdlThreadNode));
1050 if (this_thread == NULL) {
1051 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
1054 /* Initialise the thread structure */
1055 if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
1058 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
1063 * If we got here we are going to create the thread so we must initilise the structure
1064 * first because most implimentations of threading can't create it in a stopped state
1065 * and it might want to do things with its structure that aren't initialised otherwise.
1069 this_thread->name = name;
1073 this_thread->name = "Un-named Thread";
1076 this_thread->flags = flags;
1077 this_thread->thread_func = thread_func;
1078 this_thread->user_args = args;
1081 * When to start this thread
1083 this_thread->when = when;
1085 begin_critical_section(S_SCHEDULE_LIST);
1086 this_thread->next = CtdlThreadSchedList;
1087 CtdlThreadSchedList = this_thread;
1088 if (this_thread->next)
1089 this_thread->next->prev = this_thread;
1090 end_critical_section(S_SCHEDULE_LIST);
1097 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1101 begin_critical_section(S_THREAD_LIST);
1103 * We pass this_thread into the thread as its args so that it can find out information
1104 * about itself and it has a bit of storage space for itself, not to mention that the REAL
1105 * thread function needs to finish off the setup of the structure
1107 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1109 end_critical_section(S_THREAD_LIST);
1110 CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
1111 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1112 citthread_cond_destroy(&(this_thread->ThreadCond));
1113 citthread_mutex_destroy(&(this_thread->SleepMutex));
1114 citthread_cond_destroy(&(this_thread->SleepCond));
1115 citthread_attr_destroy(&this_thread->attr);
1121 num_threads++; // Increase the count of threads in the system.
1122 if(this_thread->flags & CTDLTHREAD_WORKER)
1125 this_thread->next = CtdlThreadList;
1126 CtdlThreadList = this_thread;
1127 if (this_thread->next)
1128 this_thread->next->prev = this_thread;
1130 ctdl_thread_internal_calc_loadavg();
1131 end_critical_section(S_THREAD_LIST);
1139 void ctdl_thread_internal_check_scheduled(void)
1141 CtdlThreadNode *this_thread, *that_thread;
1144 /* Don't start scheduled threads if the system wants single user mode */
1145 if (CtdlWantSingleUser())
1148 if (try_critical_section(S_SCHEDULE_LIST))
1149 return; /* If this list is locked we wait till the next chance */
1153 #ifdef WITH_THREADLOG
1154 CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1157 this_thread = CtdlThreadSchedList;
1160 that_thread = this_thread;
1161 this_thread = this_thread->next;
1163 if (now > that_thread->when)
1165 /* Unlink from schedule list */
1166 if (that_thread->prev)
1167 that_thread->prev->next = that_thread->next;
1169 CtdlThreadSchedList = that_thread->next;
1170 if (that_thread->next)
1171 that_thread->next->prev = that_thread->prev;
1173 that_thread->next = that_thread->prev = NULL;
1174 #ifdef WITH_THREADLOG
1175 CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1177 if (CT->state > CTDL_THREAD_STOP_REQ)
1178 { /* Only start it if the system is not stopping */
1179 if (ctdl_thread_internal_start_scheduled (that_thread))
1181 #ifdef WITH_THREADLOG
1182 CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (0x%08lx).\n",
1183 that_thread->name, that_thread->tid);
1188 #ifdef WITH_THREADLOG
1191 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n",
1192 that_thread->name, that_thread->when - time(NULL));
1196 end_critical_section(S_SCHEDULE_LIST);
1201 * A warapper function for select so we can show a thread as blocked
1203 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1207 ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1208 if (!CtdlThreadCheckStop())
1209 ret = select(n, readfds, writefds, exceptfds, timeout);
1211 * If the select returned <= 0 then it failed due to an error
1212 * or timeout so this thread could stop if asked to do so.
1213 * Anything else means it needs to continue unless the system is shutting down
1218 * The select says this thread needs to do something useful.
1219 * This thread was in an idle state so it may have been asked to stop
1220 * but if the system isn't shutting down this thread is no longer
1221 * idle and select has given it a task to do so it must not stop
1222 * In this condition we need to force it into the running state.
1223 * CtdlThreadGC will clear its ticker for us.
1225 * FIXME: there is still a small hole here. It is possible for the sequence of locking
1226 * to allow the state to get changed to STOP_REQ just after this code if the other thread
1227 * has decided to change the state before this lock, it there fore has to wait till the lock
1228 * completes but it will continue to change the state. We need something a bit better here.
1230 citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
1231 if (GC_thread->state > CTDL_THREAD_STOP_REQ && CT->state <= CTDL_THREAD_STOP_REQ)
1233 CtdlLogPrintf(CTDL_DEBUG, "Thread %s (0x%08lx) refused stop request.\n", CT->name, CT->tid);
1234 CT->state = CTDL_THREAD_RUNNING;
1236 citthread_mutex_unlock(&CT->ThreadMutex);
1239 ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1246 void *new_worker_thread(void *arg);
1247 extern void close_masters (void);
1250 void *simulation_worker (void*arg) {
1251 struct CitContext *this;
1253 this = CreateNewContext();
1256 this->state = CON_IDLE;
1257 dead_session_purge(1);
1258 begin_critical_section(S_SESSION_TABLE);
1260 end_critical_section(S_SESSION_TABLE);
1265 void *simulation_thread (void *arg)
1267 long stats = statcount;
1269 while(stats && !CtdlThreadCheckStop()) {
1270 CtdlThreadCreate("Connection simulation worker", CTDLTHREAD_BIGSTACK, simulation_worker, NULL);
1273 CtdlThreadStopAll();
1277 void go_threading(void)
1280 CtdlThreadNode *last_worker;
1281 struct timeval start, now, result;
1282 double last_duration;
1285 * Initialise the thread system
1287 ctdl_thread_internal_init();
1289 /* Second call to module init functions now that threading is up */
1291 initialise_modules(1);
1292 CtdlThreadCreate("select_on_master", CTDLTHREAD_BIGSTACK, select_on_master, NULL);
1295 CtdlLogPrintf(CTDL_EMERG, "Running connection simulation stats\n");
1296 gettimeofday(&start, NULL);
1297 CtdlThreadCreate("Connection simulation master", CTDLTHREAD_BIGSTACK, simulation_thread, NULL);
1302 * This thread is now used for garbage collection of other threads in the thread list
1304 CtdlLogPrintf(CTDL_INFO, "Startup thread %d becoming garbage collector,\n", citthread_self());
1307 * We do a lot of locking and unlocking of the thread list in here.
1308 * We do this so that we can repeatedly release time for other threads
1309 * that may be waiting on the thread list.
1310 * We are a low priority thread so we can afford to do this
1313 while (CtdlThreadGetCount())
1316 exit_signal = CT->signal;
1319 CtdlThreadStopAll();
1321 check_sched_shutdown();
1322 if (CT->state > CTDL_THREAD_STOP_REQ)
1324 begin_critical_section(S_THREAD_LIST);
1325 ctdl_thread_internal_calc_loadavg();
1326 end_critical_section(S_THREAD_LIST);
1328 ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1331 /* Reduce the size of the worker thread pool if necessary. */
1332 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1334 /* Ask a worker thread to stop as we no longer need it */
1335 begin_critical_section(S_THREAD_LIST);
1336 last_worker = CtdlThreadList;
1339 citthread_mutex_lock(&last_worker->ThreadMutex);
1340 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1342 citthread_mutex_unlock(&last_worker->ThreadMutex);
1345 citthread_mutex_unlock(&last_worker->ThreadMutex);
1346 last_worker = last_worker->next;
1348 end_critical_section(S_THREAD_LIST);
1351 #ifdef WITH_THREADLOG
1352 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (0x%08lx).\n",
1357 CtdlThreadStop(last_worker);
1362 * If all our workers are working hard, start some more to help out
1365 /* FIXME: come up with a better way to dynamically alter the number of threads
1366 * based on the system load
1369 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60)) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1371 /* Only start new threads if we are not going to overload the machine */
1372 /* Temporarily set to 10 should be enough to make sure we don't stranglew the server
1373 * at least until we make this a config option */
1374 if (CtdlThreadGetLoadAvg() < ((double)10.00)) {
1375 for (i=0; i<5 ; i++) {
1376 CtdlThreadCreate("Worker Thread",
1377 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1384 CtdlLogPrintf (CTDL_WARNING, "Server strangled due to machine load average too high.\n");
1390 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1395 #ifdef THREADS_USESIGNALS
1396 if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
1398 if (CtdlThreadGetCount())
1403 * If the above loop exits we must be shutting down since we obviously have no threads
1405 ctdl_thread_internal_cleanup();
1408 gettimeofday(&now, NULL);
1409 timersub(&now, &start, &result);
1410 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
1411 CtdlLogPrintf(CTDL_EMERG, "Simulated %ld connections in %f seconds\n", stats_done, last_duration);