2 * Thread handling stuff for Citadel server
4 * Copyright (c) 1987-2010 by the citadel.org team
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include <sys/types.h>
26 #include <sys/socket.h>
32 #if TIME_WITH_SYS_TIME
33 # include <sys/time.h>
37 # include <sys/time.h>
46 # if HAVE_SYS_SYSCALL_H
47 # include <sys/syscall.h>
51 #include <libcitadel.h>
54 #include "ctdl_module.h"
55 #include "modules_init.h"
56 #include "housekeeping.h"
58 #include "citserver.h"
59 #include "sysdep_decls.h"
61 #include "event_client.h"
64 * define this to use the new worker_thread method of handling connections
69 * New thread interface.
70 * To create a thread you must call one of the create thread functions.
71 * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
72 * struct CtdlThreadNode *node = NULL;
74 * If the thread is created *node will point to the thread control structure for the created thread.
75 * If the thread creation fails *node remains NULL
76 * Do not free the memory pointed to by *node, it doesn't belong to you.
77 * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
78 * remove the need for the calls to eCrashRegisterThread and friends
81 static int num_threads = 0; /* Current number of threads */
82 static int num_workers = 0; /* Current number of worker threads */
83 long statcount = 0; /* are we doing a stats check? */
84 static long stats_done = 0;
86 CtdlThreadNode *CtdlThreadList = NULL;
87 CtdlThreadNode *CtdlThreadSchedList = NULL;
89 static CtdlThreadNode *GC_thread = NULL;
90 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
91 double CtdlThreadLoadAvg = 0;
92 double CtdlThreadWorkerAvg = 0;
93 citthread_key_t ThreadKey;
95 citthread_mutex_t Critters[MAX_SEMAPHORES]; /* Things needing locking */
99 void InitialiseSemaphores(void)
103 /* Set up a bunch of semaphores to be used for critical sections */
104 for (i=0; i<MAX_SEMAPHORES; ++i) {
105 citthread_mutex_init(&Critters[i], NULL);
113 * Obtain a semaphore lock to begin a critical section.
114 * but only if no one else has one
116 int try_critical_section(int which_one)
118 /* For all types of critical sections except those listed here,
119 * ensure nobody ever tries to do a critical section within a
120 * transaction; this could lead to deadlock.
122 if ( (which_one != S_FLOORCACHE)
123 #ifdef DEBUG_MEMORY_LEAKS
124 && (which_one != S_DEBUGMEMLEAKS)
126 && (which_one != S_RPLIST)
130 return (citthread_mutex_trylock(&Critters[which_one]));
135 * Obtain a semaphore lock to begin a critical section.
137 void begin_critical_section(int which_one)
139 /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
141 /* For all types of critical sections except those listed here,
142 * ensure nobody ever tries to do a critical section within a
143 * transaction; this could lead to deadlock.
145 if ( (which_one != S_FLOORCACHE)
146 #ifdef DEBUG_MEMORY_LEAKS
147 && (which_one != S_DEBUGMEMLEAKS)
149 && (which_one != S_RPLIST)
153 citthread_mutex_lock(&Critters[which_one]);
157 * Release a semaphore lock to end a critical section.
159 void end_critical_section(int which_one)
161 citthread_mutex_unlock(&Critters[which_one]);
166 * A function to destroy the TSD
168 static void ctdl_thread_internal_dest_tsd(void *arg)
178 * A function to initialise the thread TSD
180 void ctdl_thread_internal_init_tsd(void)
184 if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
185 CtdlLogPrintf(CTDL_EMERG, "citthread_key_create: %s\n", strerror(ret));
191 * Ensure that we have a key for thread-specific data.
193 * This should be called immediately after startup by any thread
196 void CtdlThreadAllocTSD(void)
200 if (citthread_getspecific(ThreadKey) != NULL)
203 tsd = malloc(sizeof(ThreadTSD));
207 memset(tsd->cursors, 0, sizeof tsd->cursors);
210 citthread_setspecific(ThreadKey, tsd);
214 void ctdl_thread_internal_free_tsd(void)
216 ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
217 citthread_setspecific(ThreadKey, NULL);
221 void ctdl_thread_internal_cleanup(void)
224 CtdlThreadNode *this_thread, *that_thread;
226 for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
228 free (CtdlThreadStates[i]);
231 /* Clean up the scheduled thread list */
232 this_thread = CtdlThreadSchedList;
235 that_thread = this_thread;
236 this_thread = this_thread->next;
237 citthread_mutex_destroy(&that_thread->ThreadMutex);
238 citthread_cond_destroy(&that_thread->ThreadCond);
239 citthread_mutex_destroy(&that_thread->SleepMutex);
240 citthread_cond_destroy(&that_thread->SleepCond);
241 citthread_attr_destroy(&that_thread->attr);
244 ctdl_thread_internal_free_tsd();
247 void ctdl_thread_internal_init(void)
249 CtdlThreadNode *this_thread;
252 CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
253 CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
254 CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
255 CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
256 CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
257 CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
258 CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
259 CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
260 CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
261 CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
263 /* Get ourself a thread entry */
264 this_thread = malloc(sizeof(CtdlThreadNode));
265 if (this_thread == NULL) {
266 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
269 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
270 memset (this_thread, 0, sizeof(CtdlThreadNode));
272 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
273 citthread_cond_init (&(this_thread->ThreadCond), NULL);
274 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
275 citthread_cond_init (&(this_thread->SleepCond), NULL);
277 /* We are garbage collector so create us as running */
278 this_thread->state = CTDL_THREAD_RUNNING;
280 if ((ret = citthread_attr_init(&this_thread->attr))) {
281 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
286 this_thread->name = "Garbage Collection Thread";
288 this_thread->tid = citthread_self();
289 GC_thread = this_thread;
292 num_threads++; // Increase the count of threads in the system.
294 this_thread->next = CtdlThreadList;
295 CtdlThreadList = this_thread;
296 if (this_thread->next)
297 this_thread->next->prev = this_thread;
298 /* Set up start times */
299 gettimeofday(&this_thread->start_time, NULL); /* Time this thread started */
300 memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval)); /* Changed state so mark it. */
305 * A function to update a threads load averages
307 void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
309 struct timeval now, result;
310 double last_duration;
312 gettimeofday(&now, NULL);
313 timersub(&now, &(this_thread->last_state_change), &result);
314 /* I don't think these mutex's are needed here */
315 citthread_mutex_lock(&this_thread->ThreadMutex);
316 // result now has a timeval for the time we spent in the last state since we last updated
317 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
318 if (this_thread->state == CTDL_THREAD_SLEEPING)
319 this_thread->avg_sleeping += last_duration;
320 if (this_thread->state == CTDL_THREAD_RUNNING)
321 this_thread->avg_running += last_duration;
322 if (this_thread->state == CTDL_THREAD_BLOCKED)
323 this_thread->avg_blocked += last_duration;
324 memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
325 citthread_mutex_unlock(&this_thread->ThreadMutex);
329 * A function to chenge the state of a thread
331 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
334 * Wether we change state or not we need update the load values
336 ctdl_thread_internal_update_avgs(this_thread);
337 /* This mutex not needed here? */
338 citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
339 if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
340 this_thread->state = new_state;
341 if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
342 this_thread->state = new_state;
343 if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
344 this_thread->state = new_state;
345 citthread_mutex_unlock(&this_thread->ThreadMutex);
350 * A function to tell all threads to exit
352 void CtdlThreadStopAll(void)
354 /* First run any registered shutdown hooks. This probably doesn't belong here. */
355 PerformSessionHooks(EVT_SHUTDOWN);
357 /* then close all tcp ports so nobody else can talk to us anymore. */
358 CtdlShutdownServiceHooks();
359 //FIXME: The signalling of the condition should not be in the critical_section
360 // We need to build a list of threads we are going to signal and then signal them afterwards
362 ShutDownEventQueue();
364 CtdlThreadNode *this_thread;
366 begin_critical_section(S_THREAD_LIST);
367 this_thread = CtdlThreadList;
368 // Ask the GC thread to stop first so everything knows we are shutting down.
369 GC_thread->state = CTDL_THREAD_STOP_REQ;
372 if (!citthread_equal(this_thread->tid, GC_thread->tid))
373 citthread_kill(this_thread->tid, SIGHUP);
375 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
376 citthread_cond_signal(&this_thread->ThreadCond);
377 citthread_cond_signal(&this_thread->SleepCond);
378 this_thread->stop_ticker = time(NULL);
379 CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
380 this_thread->name, this_thread->tid);
381 this_thread = this_thread->next;
383 end_critical_section(S_THREAD_LIST);
388 * A function to wake up all sleeping threads
390 void CtdlThreadWakeAll(void)
392 CtdlThreadNode *this_thread;
394 CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
396 begin_critical_section(S_THREAD_LIST);
397 this_thread = CtdlThreadList;
400 if (!this_thread->thread_func)
402 citthread_cond_signal(&this_thread->ThreadCond);
403 citthread_cond_signal(&this_thread->SleepCond);
405 this_thread = this_thread->next;
407 end_critical_section(S_THREAD_LIST);
412 * A function to return the number of threads running in the system
414 int CtdlThreadGetCount(void)
419 int CtdlThreadGetWorkers(void)
424 double CtdlThreadGetWorkerAvg(void)
428 begin_critical_section(S_THREAD_LIST);
429 ret = CtdlThreadWorkerAvg;
430 end_critical_section(S_THREAD_LIST);
434 double CtdlThreadGetLoadAvg(void)
436 double load_avg[3] = {0.0, 0.0, 0.0};
441 /* Borrowed this straight from procps */
442 smp_num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
443 if(smp_num_cpus<1) smp_num_cpus=1; /* SPARC glibc is buggy */
445 #ifdef HAVE_GETLOADAVG
446 ret = getloadavg(load_avg, 3);
450 return load_avg[0] / smp_num_cpus;
452 * This old chunk of code return a value that indicated the load on citserver
453 * This value could easily reach 100 % even when citserver was doing very little and
454 * hence the machine has much more spare capacity.
455 * Because this value was used to determine if the machine was under heavy load conditions
456 * from other processes in the system then citserver could be strangled un-necesarily
457 * What we are actually trying to achieve is to strangle citserver if the machine is heavily loaded.
458 * So we have changed this.
460 begin_critical_section(S_THREAD_LIST);
461 ret = CtdlThreadLoadAvg;
462 end_critical_section(S_THREAD_LIST);
471 * A function to rename a thread
472 * Returns a const char *
474 const char *CtdlThreadName(const char *name)
476 const char *old_name;
480 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
491 * A function to force a thread to exit
493 void CtdlThreadCancel(CtdlThreadNode *thread)
495 CtdlThreadNode *this_thread;
500 this_thread = thread;
503 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
508 if (!this_thread->thread_func)
510 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
515 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
516 citthread_cancel(this_thread->tid);
521 * A function for a thread to check if it has been asked to stop
523 int CtdlThreadCheckStop(void)
529 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
538 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
539 if (CT->signal == SIGHUP)
540 CT->state = CTDL_THREAD_STOP_REQ;
543 if(state == CTDL_THREAD_STOP_REQ)
545 CT->state = CTDL_THREAD_STOPPING;
548 else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
557 * A function to ask a thread to exit
558 * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
560 void CtdlThreadStop(CtdlThreadNode *thread)
562 CtdlThreadNode *this_thread;
567 this_thread = thread;
570 if (!(this_thread->thread_func))
571 return; // Don't stop garbage collector
573 if (!citthread_equal(this_thread->tid, GC_thread->tid))
574 citthread_kill(this_thread->tid, SIGHUP);
576 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
577 citthread_cond_signal(&this_thread->ThreadCond);
578 citthread_cond_signal(&this_thread->SleepCond);
579 this_thread->stop_ticker = time(NULL);
583 * So we now have a sleep command that works with threads but it is in seconds
585 void CtdlThreadSleep(int secs)
587 struct timespec wake_time;
588 struct timeval time_now;
593 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
597 memset (&wake_time, 0, sizeof(struct timespec));
598 gettimeofday(&time_now, NULL);
599 wake_time.tv_sec = time_now.tv_sec + secs;
600 wake_time.tv_nsec = time_now.tv_usec * 10;
602 ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
604 citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
605 citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
606 citthread_mutex_unlock(&CT->ThreadMutex);
608 ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
613 * Routine to clean up our thread function on exit
615 static void ctdl_internal_thread_cleanup(void *arg)
618 * In here we were called by the current thread because it is exiting
619 * NB. WE ARE THE CURRENT THREAD
623 const char *name = CT->name;
624 const pid_t tid = CT->tid;
626 CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (0x%08lx) exited.\n", name, (unsigned long) tid);
630 CtdlLogPrintf(CTDL_NOTICE, "some ((unknown ? ? ?) Thread exited.\n");
633 #ifdef HAVE_BACKTRACE
634 /// eCrash_UnregisterThread();
637 citthread_mutex_lock(&CT->ThreadMutex);
638 CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
639 citthread_mutex_unlock(&CT->ThreadMutex);
643 * A quick function to show the load averages
645 void ctdl_thread_internal_calc_loadavg(void)
647 CtdlThreadNode *that_thread;
648 double load_avg, worker_avg;
651 that_thread = CtdlThreadList;
656 /* Update load averages */
657 ctdl_thread_internal_update_avgs(that_thread);
658 citthread_mutex_lock(&that_thread->ThreadMutex);
659 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;
660 that_thread->avg_sleeping /= 2;
661 that_thread->avg_running /= 2;
662 that_thread->avg_blocked /= 2;
663 load_avg += that_thread->load_avg;
664 if (that_thread->flags & CTDLTHREAD_WORKER)
666 worker_avg += that_thread->load_avg;
669 #ifdef WITH_THREADLOG
670 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
673 CtdlThreadStates[that_thread->state],
674 that_thread->avg_sleeping,
675 that_thread->avg_running,
676 that_thread->avg_blocked,
677 that_thread->load_avg);
679 citthread_mutex_unlock(&that_thread->ThreadMutex);
680 that_thread = that_thread->next;
682 CtdlThreadLoadAvg = load_avg/num_threads;
683 CtdlThreadWorkerAvg = worker_avg/workers;
684 #ifdef WITH_THREADLOG
685 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);
691 * Garbage collection routine.
692 * Gets called by main() in a loop to clean up the thread list periodically.
694 void CtdlThreadGC (void)
696 CtdlThreadNode *this_thread, *that_thread;
697 int workers = 0, sys_workers;
700 begin_critical_section(S_THREAD_LIST);
702 /* Handle exiting of garbage collector thread */
704 CtdlThreadList->state = CTDL_THREAD_EXITED;
706 #ifdef WITH_THREADLOG
707 CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
710 * Woke up to do garbage collection
712 this_thread = CtdlThreadList;
715 that_thread = this_thread;
716 this_thread = this_thread->next;
718 if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
719 && (!citthread_equal(that_thread->tid, citthread_self())))
721 CtdlLogPrintf(CTDL_DEBUG, "Waiting for thread %s (0x%08lx) to exit.\n", that_thread->name, that_thread->tid);
722 terminate_stuck_sessions();
727 * Catch the situation where a worker was asked to stop but couldn't and we are not
730 that_thread->stop_ticker = 0;
733 if (that_thread->stop_ticker + 5 == time(NULL))
735 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);
736 if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
737 CtdlLogPrintf(CTDL_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
738 // that_thread->state = CTDL_THREAD_CANCELLED;
739 that_thread->stop_ticker++;
740 // citthread_cancel(that_thread->tid);
744 /* Do we need to clean up this thread? */
745 if ((that_thread->state != CTDL_THREAD_EXITED) && (that_thread->state != CTDL_THREAD_CANCELLED))
747 if(that_thread->flags & CTDLTHREAD_WORKER)
748 workers++; /* Sanity check on number of worker threads */
752 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
754 end_critical_section(S_THREAD_LIST);
755 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
760 if (num_threads <= 0)
762 end_critical_section(S_THREAD_LIST);
763 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
768 if(that_thread->flags & CTDLTHREAD_WORKER)
769 num_workers--; /* This is a wroker thread so reduce the count. */
771 /* If we are unlinking the list head then the next becomes the list head */
772 if(that_thread->prev)
773 that_thread->prev->next = that_thread->next;
775 CtdlThreadList = that_thread->next;
776 if(that_thread->next)
777 that_thread->next->prev = that_thread->prev;
779 citthread_cond_signal(&that_thread->ThreadCond);
780 citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
781 citthread_mutex_lock(&that_thread->ThreadMutex); // Make sure it has done what its doing
782 citthread_mutex_unlock(&that_thread->ThreadMutex);
784 * Join on the thread to do clean up and prevent memory leaks
785 * Also makes sure the thread has cleaned up after itself before we remove it from the list
786 * We can join on the garbage collector thread the join should just return EDEADLCK
788 ret = citthread_join (that_thread->tid, NULL);
790 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
791 else if (ret == EINVAL)
792 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
793 else if (ret == ESRCH)
794 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
796 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, citthread_join returned an unknown error(%d).\n", ret);
798 * Now we own that thread entry
800 CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (0x%08lx).\n",
801 that_thread->name, that_thread->tid);
802 citthread_mutex_destroy(&that_thread->ThreadMutex);
803 citthread_cond_destroy(&that_thread->ThreadCond);
804 citthread_mutex_destroy(&that_thread->SleepMutex);
805 citthread_cond_destroy(&that_thread->SleepCond);
806 citthread_attr_destroy(&that_thread->attr);
809 sys_workers = num_workers;
810 end_critical_section(S_THREAD_LIST);
812 /* Sanity check number of worker threads */
813 if (workers != sys_workers)
815 CtdlLogPrintf(CTDL_EMERG,
816 "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
827 * Runtime function for a Citadel Thread.
828 * This initialises the threads environment and then calls the user supplied thread function
829 * Note that this is the REAL thread function and wraps the users thread function.
831 static void *ctdl_internal_thread_func (void *arg)
833 CtdlThreadNode *this_thread;
836 /* lock and unlock the thread list.
837 * This causes this thread to wait until all its creation stuff has finished before it
838 * can continue its execution.
840 begin_critical_section(S_THREAD_LIST);
841 this_thread = (CtdlThreadNode *) arg;
842 gettimeofday(&this_thread->start_time, NULL); /* Time this thread started */
844 // Register the cleanup function to take care of when we exit.
845 citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
846 // Get our thread data structure
847 CtdlThreadAllocTSD();
849 this_thread->pid = getpid();
850 memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval)); /* Changed state so mark it. */
851 /* Only change to running state if we weren't asked to stop during the create cycle
852 * Other wise there is a window to allow this threads creation to continue to full grown and
853 * therby prevent a shutdown of the server.
855 if (!CtdlThreadCheckStop())
857 citthread_mutex_lock(&this_thread->ThreadMutex);
858 this_thread->state = CTDL_THREAD_RUNNING;
859 citthread_mutex_unlock(&this_thread->ThreadMutex);
861 end_critical_section(S_THREAD_LIST);
863 // Register for tracing
864 #ifdef HAVE_BACKTRACE
865 /// eCrash_RegisterThread(this_thread->name, 0);
868 // Tell the world we are here
869 #if defined(HAVE_SYSCALL_H) && defined (SYS_gettid)
870 this_thread->reltid = syscall(SYS_gettid);
872 CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (0x%08lx).\n",
873 this_thread->name, this_thread->tid);
876 * run the thread to do the work but only if we haven't been asked to stop
878 if (!CtdlThreadCheckStop())
879 ret = (this_thread->thread_func)(this_thread->user_args);
882 * Our thread is exiting either because it wanted to end or because the server is stopping
883 * We need to clean up
885 citthread_cleanup_pop(1); // Execute our cleanup routine and remove it
894 * Function to initialise an empty thread structure
896 CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
900 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
901 memset (this_thread, 0, sizeof(CtdlThreadNode));
903 /* Create the mutex's early so we can use them */
904 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
905 citthread_cond_init (&(this_thread->ThreadCond), NULL);
906 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
907 citthread_cond_init (&(this_thread->SleepCond), NULL);
909 this_thread->state = CTDL_THREAD_CREATE;
911 if ((ret = citthread_attr_init(&this_thread->attr))) {
912 citthread_mutex_unlock(&this_thread->ThreadMutex);
913 citthread_mutex_destroy(&(this_thread->ThreadMutex));
914 citthread_cond_destroy(&(this_thread->ThreadCond));
915 citthread_mutex_destroy(&(this_thread->SleepMutex));
916 citthread_cond_destroy(&(this_thread->SleepCond));
917 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
922 /* Our per-thread stacks need to be bigger than the default size,
923 * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
924 * crashes on 64-bit Linux.
926 if (flags & CTDLTHREAD_BIGSTACK)
928 #ifdef WITH_THREADLOG
929 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
931 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
932 citthread_mutex_unlock(&this_thread->ThreadMutex);
933 citthread_mutex_destroy(&(this_thread->ThreadMutex));
934 citthread_cond_destroy(&(this_thread->ThreadCond));
935 citthread_mutex_destroy(&(this_thread->SleepMutex));
936 citthread_cond_destroy(&(this_thread->SleepCond));
937 citthread_attr_destroy(&this_thread->attr);
938 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
945 /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
946 * load average for the system. If we don't do this then we create a mass of threads at the same time
947 * because the creation didn't affect the load average.
949 this_thread->avg_blocked = 2;
951 return (this_thread);
958 * Internal function to create a thread.
960 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
963 CtdlThreadNode *this_thread;
965 if (num_threads >= 32767)
967 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
971 this_thread = malloc(sizeof(CtdlThreadNode));
972 if (this_thread == NULL) {
973 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
977 /* Initialise the thread structure */
978 if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
981 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
985 * If we got here we are going to create the thread so we must initilise the structure
986 * first because most implimentations of threading can't create it in a stopped state
987 * and it might want to do things with its structure that aren't initialised otherwise.
991 this_thread->name = name;
995 this_thread->name = "Un-named Thread";
998 this_thread->flags = flags;
999 this_thread->thread_func = thread_func;
1000 this_thread->user_args = args;
1002 begin_critical_section(S_THREAD_LIST);
1004 * We pass this_thread into the thread as its args so that it can find out information
1005 * about itself and it has a bit of storage space for itself, not to mention that the REAL
1006 * thread function needs to finish off the setup of the structure
1008 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1010 end_critical_section(S_THREAD_LIST);
1011 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
1013 citthread_mutex_unlock(&this_thread->ThreadMutex);
1014 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1015 citthread_cond_destroy(&(this_thread->ThreadCond));
1016 citthread_mutex_destroy(&(this_thread->SleepMutex));
1017 citthread_cond_destroy(&(this_thread->SleepCond));
1018 citthread_attr_destroy(&this_thread->attr);
1022 num_threads++; // Increase the count of threads in the system.
1023 if(this_thread->flags & CTDLTHREAD_WORKER)
1026 this_thread->next = CtdlThreadList;
1027 CtdlThreadList = this_thread;
1028 if (this_thread->next)
1029 this_thread->next->prev = this_thread;
1030 ctdl_thread_internal_calc_loadavg();
1032 end_critical_section(S_THREAD_LIST);
1038 * Wrapper function to create a thread
1039 * ensures the critical section and other protections are in place.
1040 * char *name = name to give to thread, if NULL, use generic name
1041 * int flags = flags to determine type of thread and standard facilities
1043 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
1045 CtdlThreadNode *ret = NULL;
1047 ret = ctdl_internal_create_thread(name, flags, thread_func, args);
1053 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1057 begin_critical_section(S_THREAD_LIST);
1059 * We pass this_thread into the thread as its args so that it can find out information
1060 * about itself and it has a bit of storage space for itself, not to mention that the REAL
1061 * thread function needs to finish off the setup of the structure
1063 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1065 end_critical_section(S_THREAD_LIST);
1066 CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
1067 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1068 citthread_cond_destroy(&(this_thread->ThreadCond));
1069 citthread_mutex_destroy(&(this_thread->SleepMutex));
1070 citthread_cond_destroy(&(this_thread->SleepCond));
1071 citthread_attr_destroy(&this_thread->attr);
1077 num_threads++; // Increase the count of threads in the system.
1078 if(this_thread->flags & CTDLTHREAD_WORKER)
1081 this_thread->next = CtdlThreadList;
1082 CtdlThreadList = this_thread;
1083 if (this_thread->next)
1084 this_thread->next->prev = this_thread;
1086 ctdl_thread_internal_calc_loadavg();
1087 end_critical_section(S_THREAD_LIST);
1095 void ctdl_thread_internal_check_scheduled(void)
1097 CtdlThreadNode *this_thread, *that_thread;
1100 /* Don't start scheduled threads if the system wants single user mode */
1101 if (CtdlWantSingleUser())
1104 if (try_critical_section(S_SCHEDULE_LIST))
1105 return; /* If this list is locked we wait till the next chance */
1109 #ifdef WITH_THREADLOG
1110 CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1113 this_thread = CtdlThreadSchedList;
1116 that_thread = this_thread;
1117 this_thread = this_thread->next;
1119 if (now > that_thread->when)
1121 /* Unlink from schedule list */
1122 if (that_thread->prev)
1123 that_thread->prev->next = that_thread->next;
1125 CtdlThreadSchedList = that_thread->next;
1126 if (that_thread->next)
1127 that_thread->next->prev = that_thread->prev;
1129 that_thread->next = that_thread->prev = NULL;
1130 #ifdef WITH_THREADLOG
1131 CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1133 if (CT->state > CTDL_THREAD_STOP_REQ)
1134 { /* Only start it if the system is not stopping */
1135 if (ctdl_thread_internal_start_scheduled (that_thread))
1137 #ifdef WITH_THREADLOG
1138 CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (0x%08lx).\n",
1139 that_thread->name, that_thread->tid);
1144 #ifdef WITH_THREADLOG
1147 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n",
1148 that_thread->name, that_thread->when - time(NULL));
1152 end_critical_section(S_SCHEDULE_LIST);
1157 * A warapper function for select so we can show a thread as blocked
1159 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1163 ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1164 if (!CtdlThreadCheckStop())
1165 ret = select(n, readfds, writefds, exceptfds, timeout);
1167 * If the select returned <= 0 then it failed due to an error
1168 * or timeout so this thread could stop if asked to do so.
1169 * Anything else means it needs to continue unless the system is shutting down
1174 * The select says this thread needs to do something useful.
1175 * This thread was in an idle state so it may have been asked to stop
1176 * but if the system isn't shutting down this thread is no longer
1177 * idle and select has given it a task to do so it must not stop
1178 * In this condition we need to force it into the running state.
1179 * CtdlThreadGC will clear its ticker for us.
1181 * FIXME: there is still a small hole here. It is possible for the sequence of locking
1182 * to allow the state to get changed to STOP_REQ just after this code if the other thread
1183 * has decided to change the state before this lock, it there fore has to wait till the lock
1184 * completes but it will continue to change the state. We need something a bit better here.
1186 citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
1187 if (GC_thread->state > CTDL_THREAD_STOP_REQ && CT->state <= CTDL_THREAD_STOP_REQ)
1189 CtdlLogPrintf(CTDL_DEBUG, "Thread %s (0x%08lx) refused stop request.\n", CT->name, CT->tid);
1190 CT->state = CTDL_THREAD_RUNNING;
1192 citthread_mutex_unlock(&CT->ThreadMutex);
1195 ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1202 void *new_worker_thread(void *arg);
1203 extern void close_masters (void);
1206 void *simulation_worker (void*arg) {
1207 struct CitContext *this;
1209 this = CreateNewContext();
1212 this->state = CON_IDLE;
1213 dead_session_purge(1);
1214 begin_critical_section(S_SESSION_TABLE);
1216 end_critical_section(S_SESSION_TABLE);
1221 void *simulation_thread (void *arg)
1223 long stats = statcount;
1225 while(stats && !CtdlThreadCheckStop()) {
1226 CtdlThreadCreate("Connection simulation worker", CTDLTHREAD_BIGSTACK, simulation_worker, NULL);
1229 CtdlThreadStopAll();
1233 void go_threading(void)
1236 CtdlThreadNode *last_worker;
1237 struct timeval start, now, result;
1238 double last_duration;
1241 * Initialise the thread system
1243 ctdl_thread_internal_init();
1245 /* Second call to module init functions now that threading is up */
1247 initialise_modules(1);
1248 CtdlThreadCreate("select_on_master", CTDLTHREAD_BIGSTACK, select_on_master, NULL);
1251 CtdlLogPrintf(CTDL_EMERG, "Running connection simulation stats\n");
1252 gettimeofday(&start, NULL);
1253 CtdlThreadCreate("Connection simulation master", CTDLTHREAD_BIGSTACK, simulation_thread, NULL);
1258 * This thread is now used for garbage collection of other threads in the thread list
1260 CtdlLogPrintf(CTDL_INFO, "Startup thread %ld becoming garbage collector,\n", (long) citthread_self());
1263 * We do a lot of locking and unlocking of the thread list in here.
1264 * We do this so that we can repeatedly release time for other threads
1265 * that may be waiting on the thread list.
1266 * We are a low priority thread so we can afford to do this
1269 while (CtdlThreadGetCount())
1272 exit_signal = CT->signal;
1275 CtdlThreadStopAll();
1277 check_sched_shutdown();
1278 if (CT->state > CTDL_THREAD_STOP_REQ)
1280 begin_critical_section(S_THREAD_LIST);
1281 ctdl_thread_internal_calc_loadavg();
1282 end_critical_section(S_THREAD_LIST);
1284 ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1287 /* Reduce the size of the worker thread pool if necessary. */
1288 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1290 /* Ask a worker thread to stop as we no longer need it */
1291 begin_critical_section(S_THREAD_LIST);
1292 last_worker = CtdlThreadList;
1295 citthread_mutex_lock(&last_worker->ThreadMutex);
1296 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1298 citthread_mutex_unlock(&last_worker->ThreadMutex);
1301 citthread_mutex_unlock(&last_worker->ThreadMutex);
1302 last_worker = last_worker->next;
1304 end_critical_section(S_THREAD_LIST);
1307 #ifdef WITH_THREADLOG
1308 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (0x%08lx).\n",
1313 CtdlThreadStop(last_worker);
1318 * If all our workers are working hard, start some more to help out
1321 /* FIXME: come up with a better way to dynamically alter the number of threads
1322 * based on the system load
1325 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60)) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1327 /* Only start new threads if we are not going to overload the machine */
1328 /* Temporarily set to 10 should be enough to make sure we don't stranglew the server
1329 * at least until we make this a config option */
1330 if (CtdlThreadGetLoadAvg() < ((double)10.00)) {
1331 for (i=0; i<5 ; i++) {
1332 CtdlThreadCreate("Worker Thread",
1333 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1340 CtdlLogPrintf (CTDL_WARNING, "Server strangled due to machine load average too high.\n");
1346 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1351 #ifdef THREADS_USESIGNALS
1352 if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
1354 if (CtdlThreadGetCount())
1359 * If the above loop exits we must be shutting down since we obviously have no threads
1361 ctdl_thread_internal_cleanup();
1364 gettimeofday(&now, NULL);
1365 timersub(&now, &start, &result);
1366 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
1367 CtdlLogPrintf(CTDL_EMERG, "Simulated %ld connections in %f seconds\n", stats_done, last_duration);