/*
- * $Id: sysdep.c 5882 2007-12-13 19:46:05Z davew $
+ * $Id$
*
* Citadel "system dependent" stuff.
- * See copyright.txt for copyright information.
+ * See COPYING for copyright information.
*
* Here's where we have the Citadel thread implimentation
*
*/
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
#include <sys/types.h>
#include <errno.h>
#include <sys/socket.h>
#include <unistd.h>
#include <fcntl.h>
+#include <signal.h>
#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# endif
#endif
+#include <libcitadel.h>
+
#include "threads.h"
#include "ctdl_module.h"
#include "modules_init.h"
#include "config.h"
#include "citserver.h"
#include "sysdep_decls.h"
+#include "context.h"
/*
* define this to use the new worker_thread method of handling connections
CtdlThreadNode *CtdlThreadList = NULL;
CtdlThreadNode *CtdlThreadSchedList = NULL;
-static citthread_t GC_thread;
+static CtdlThreadNode *GC_thread = NULL;
static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
double CtdlThreadLoadAvg = 0;
double CtdlThreadWorkerAvg = 0;
int ret;
if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
- lprintf(CTDL_EMERG, "citthread_key_create: %s\n", strerror(ret));
+ CtdlLogPrintf(CTDL_EMERG, "citthread_key_create: %s\n", strerror(ret));
exit(CTDLEXIT_DB);
}
}
CtdlThreadNode *this_thread;
int ret = 0;
- GC_thread = citthread_self();
CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
this_thread->name = "Garbage Collection Thread";
- this_thread->tid = GC_thread;
+ this_thread->tid = citthread_self();
+ GC_thread = this_thread;
CT = this_thread;
num_threads++; // Increase the count of threads in the system.
*/
void CtdlThreadStopAll(void)
{
+ /* First run any registered shutdown hooks. This probably doesn't belong here. */
+ PerformSessionHooks(EVT_SHUTDOWN);
+
//FIXME: The signalling of the condition should not be in the critical_section
// We need to build a list of threads we are going to signal and then signal them afterwards
begin_critical_section(S_THREAD_LIST);
this_thread = CtdlThreadList;
+ // Ask the GC thread to stop first so everything knows we are shutting down.
+ GC_thread->state = CTDL_THREAD_STOP_REQ;
while(this_thread)
{
#ifdef THREADS_USESIGNALS
- citthread_killl(this_thread->tid, SIGHUP);
+ if (!citthread_equal(this_thread->tid, GC_thread->tid))
+ citthread_kill(this_thread->tid, SIGHUP);
#endif
ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
citthread_cond_signal(&this_thread->ThreadCond);
citthread_cond_signal(&this_thread->SleepCond);
+ this_thread->stop_ticker = time(NULL);
CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
this_thread->name, this_thread->tid);
this_thread = this_thread->next;
double CtdlThreadGetLoadAvg(void)
{
- double ret;
-
+ double load_avg[3] ;
+
+ int ret;
+ int smp_num_cpus;
+
+ /* Borrowed this straight from procps */
+ smp_num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+ if(smp_num_cpus<1) smp_num_cpus=1; /* SPARC glibc is buggy */
+
+ ret = getloadavg(load_avg, 3);
+ if (ret < 0)
+ return 0;
+ return load_avg[0] / smp_num_cpus;
+/*
+ * This old chunk of code return a value that indicated the load on citserver
+ * This value could easily reach 100 % even when citserver was doing very little and
+ * hence the machine has much more spare capacity.
+ * Because this value was used to determine if the machine was under heavy load conditions
+ * from other processes in the system then citserver could be strangled un-necesarily
+ * What we are actually trying to achieve is to strangle citserver if the machine is heavily loaded.
+ * So we have changed this.
+
begin_critical_section(S_THREAD_LIST);
ret = CtdlThreadLoadAvg;
end_critical_section(S_THREAD_LIST);
return ret;
+*/
}
state = CT->state;
-#ifdef THREADS_USERSIGNALS
+#ifdef THREADS_USESIGNALS
if (CT->signal)
+ {
CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
+ CT->signal = 0;
+ }
#endif
if(state == CTDL_THREAD_STOP_REQ)
{
if (!(this_thread->thread_func))
return; // Don't stop garbage collector
#ifdef THREADS_USESIGNALS
- citthread_kill(this_thread->tid, SIGHUP);
+ if (!citthread_equal(this_thread->tid, GC_thread->tid))
+ citthread_kill(this_thread->tid, SIGHUP);
#endif
ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
citthread_cond_signal(&this_thread->ThreadCond);
citthread_cond_signal(&this_thread->SleepCond);
+ this_thread->stop_ticker = time(NULL);
}
/*
CtdlThreadLoadAvg = load_avg/num_threads;
CtdlThreadWorkerAvg = worker_avg/workers;
#ifdef WITH_THREADLOG
- CtdlLogPrintf(CTDL_INFO, "System load average %.2f, workers averag %.2f, threads %d, workers %d, sessions %d\n", CtdlThreadLoadAvg, CtdlThreadWorkerAvg, num_threads, num_workers, num_sessions);
+ 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);
#endif
}
if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
&& (!citthread_equal(that_thread->tid, citthread_self())))
- that_thread->stop_ticker++;
+ CtdlLogPrintf(CTDL_DEBUG, "Waiting for thread %s (0x%08lx) to exit.\n", that_thread->name, that_thread->tid);
+ else
+ {
+ /**
+ * Catch the situation where a worker was asked to stop but couldn't and we are not
+ * shutting down.
+ */
+ that_thread->stop_ticker = 0;
+ }
- if (that_thread->stop_ticker == 5)
+ if (that_thread->stop_ticker + 5 == time(NULL))
{
- CtdlLogPrintf(CTDL_DEBUG, "Thread System: The thread \"%s\" (0x%08lx) failed to self terminate withing 5 ticks. Canceling it.\n", that_thread->name, that_thread->tid);
+ 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);
if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
- CtdlLogPrintf(CTDL_INFO, "Thread System: A non worker thread was canceled this may cause message loss.\n");
- that_thread->state = CTDL_THREAD_CANCELLED;
+ CtdlLogPrintf(CTDL_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
+// that_thread->state = CTDL_THREAD_CANCELLED;
that_thread->stop_ticker++;
- citthread_cancel(that_thread->tid);
- continue;
+// citthread_cancel(that_thread->tid);
+// continue;
}
/* Do we need to clean up this thread? */
CtdlThreadNode *this_thread, *that_thread;
time_t now;
+ /* Don't start scheduled threads if the system wants single user mode */
+ if (CtdlWantSingleUser())
+ return;
+
if (try_critical_section(S_SCHEDULE_LIST))
return; /* If this list is locked we wait till the next chance */
if (ctdl_thread_internal_start_scheduled (that_thread))
{
#ifdef WITH_THREADLOG
- CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (%ud).\n",
+ CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (0x%08lx).\n",
that_thread->name, that_thread->tid);
#endif
}
*/
int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
{
- int ret;
+ int ret = 0;
ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
- ret = select(n, readfds, writefds, exceptfds, timeout);
+ if (!CtdlThreadCheckStop())
+ ret = select(n, readfds, writefds, exceptfds, timeout);
+ /**
+ * If the select returned <= 0 then it failed due to an error
+ * or timeout so this thread could stop if asked to do so.
+ * Anything else means it needs to continue unless the system is shutting down
+ */
+ if (ret > 0)
+ {
+ /**
+ * The select says this thread needs to do something useful.
+ * This thread was in an idle state so it may have been asked to stop
+ * but if the system isn't shutting down this thread is no longer
+ * idle and select has given it a task to do so it must not stop
+ * In this condition we need to force it into the running state.
+ * CtdlThreadGC will clear its ticker for us.
+ *
+ * FIXME: there is still a small hole here. It is possible for the sequence of locking
+ * to allow the state to get changed to STOP_REQ just after this code if the other thread
+ * has decided to change the state before this lock, it there fore has to wait till the lock
+ * completes but it will continue to change the state. We need something a bit better here.
+ */
+ citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
+ if (GC_thread->state > CTDL_THREAD_STOP_REQ && CT->state <= CTDL_THREAD_STOP_REQ)
+ {
+ CtdlLogPrintf(CTDL_DEBUG, "Thread %s (0x%08lx) refused stop request.\n", CT->name, CT->tid);
+ CT->state = CTDL_THREAD_RUNNING;
+ }
+ citthread_mutex_unlock(&CT->ThreadMutex);
+ }
+
ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
+
return ret;
}
#ifdef NEW_WORKER
if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkers() <= num_sessions) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
#else
- if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60) && (CtdlThreadGetLoadAvg() < 90) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
+ if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60)) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
#endif /* NEW_WORKER */
{
- for (i=0; i<5 ; i++)
- {
+ /* Only start new threads if we are not going to overload the machine */
+ if (CtdlThreadGetLoadAvg() < ((double)1.00)) {
+ for (i=0; i<5 ; i++) {
#ifdef NEW_WORKER
- CtdlThreadCreate("Worker Thread (new)",
- CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
- new_worker_thread,
- NULL
- );
+ CtdlThreadCreate("Worker Thread (new)",
+ CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
+ new_worker_thread,
+ NULL
+ );
#else
- CtdlThreadCreate("Worker Thread",
- CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
- worker_thread,
- NULL
- );
+ CtdlThreadCreate("Worker Thread",
+ CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
+ worker_thread,
+ NULL
+ );
#endif /* NEW_WORKER */
+ }
}
+ else
+ CtdlLogPrintf (CTDL_WARNING, "Server strangled due to machine load average too high.\n");
}
CtdlThreadGC();
-
+
if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
{
CtdlThreadGC();
}
+#ifdef THREADS_USESIGNALS
+ if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
+#else
if (CtdlThreadGetCount())
+#endif
CtdlThreadSleep(1);
}
/*
-extern void dead_session_purge(int force);
/*
* A new worker_thread loop.
projects / citadel.git / blobdiff