2 This file is part of GNUnet
3 (C) 2009, 2011 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @file util/scheduler.c
23 * @brief schedule computations using continuation passing style
24 * @author Christian Grothoff
27 #include "gnunet_common.h"
28 #include "gnunet_os_lib.h"
29 #include "gnunet_scheduler_lib.h"
30 #include "gnunet_signal_lib.h"
31 #include "gnunet_time_lib.h"
33 #define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
35 #define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall)
42 * Use lsof to generate file descriptor reports on select error?
43 * (turn off for stable releases).
45 #define USE_LSOF GNUNET_NO
48 * Obtain trace information for all scheduler calls that schedule tasks.
50 #define EXECINFO GNUNET_NO
53 * Check each file descriptor before adding
55 #define DEBUG_FDS GNUNET_EXTRA_LOGGING
58 * Depth of the traces collected via EXECINFO.
60 #define MAX_TRACE_DEPTH 50
63 #define DEBUG_TASKS GNUNET_EXTRA_LOGGING
66 * Should we figure out which tasks are delayed for a while
67 * before they are run? (Consider using in combination with EXECINFO).
69 #define PROFILE_DELAYS GNUNET_NO
72 * Task that were in the queue for longer than this are reported if
73 * PROFILE_DELAYS is active.
75 #define DELAY_THRESHOLD GNUNET_TIME_UNIT_SECONDS
78 * Linked list of pending tasks.
83 * This is a linked list.
88 * Function to run when ready.
90 GNUNET_SCHEDULER_Task callback;
93 * Closure for the callback.
98 * Set of file descriptors this task is waiting
99 * for for reading. Once ready, this is updated
100 * to reflect the set of file descriptors ready
103 struct GNUNET_NETWORK_FDSet *read_set;
106 * Set of file descriptors this task is waiting for for writing.
107 * Once ready, this is updated to reflect the set of file
108 * descriptors ready for operation.
110 struct GNUNET_NETWORK_FDSet *write_set;
113 * Unique task identifier.
115 GNUNET_SCHEDULER_TaskIdentifier id;
118 * Identifier of a prerequisite task.
120 GNUNET_SCHEDULER_TaskIdentifier prereq_id;
123 * Absolute timeout value for the task, or
124 * GNUNET_TIME_UNIT_FOREVER_ABS for "no timeout".
126 struct GNUNET_TIME_Absolute timeout;
130 * When was the task scheduled?
132 struct GNUNET_TIME_Absolute start_time;
136 * Why is the task ready? Set after task is added to ready queue.
137 * Initially set to zero. All reasons that have already been
138 * satisfied (i.e. read or write ready) will be set over time.
140 enum GNUNET_SCHEDULER_Reason reason;
145 enum GNUNET_SCHEDULER_Priority priority;
148 * Set if we only wait for reading from a single FD, otherwise -1.
153 * Set if we only wait for writing to a single FD, otherwise -1.
158 * Should the existence of this task in the queue be counted as
159 * reason to not shutdown the scheduler?
165 * Array of strings which make up a backtrace from the point when this
166 * task was scheduled (essentially, who scheduled the task?)
168 char **backtrace_strings;
171 * Size of the backtrace_strings array
173 int num_backtrace_strings;
181 * List of tasks waiting for an event.
183 static struct Task *pending;
186 * List of tasks waiting ONLY for a timeout event.
187 * Sorted by timeout (earliest first). Used so that
188 * we do not traverse the list of these tasks when
189 * building select sets (we just look at the head
190 * to determine the respective timeout ONCE).
192 static struct Task *pending_timeout;
195 * Last inserted task waiting ONLY for a timeout event.
196 * Used to (heuristically) speed up insertion.
198 static struct Task *pending_timeout_last;
201 * ID of the task that is running right now.
203 static struct Task *active_task;
206 * List of tasks ready to run right now,
207 * grouped by importance.
209 static struct Task *ready[GNUNET_SCHEDULER_PRIORITY_COUNT];
212 * Identity of the last task queued. Incremented for each task to
213 * generate a unique task ID (it is virtually impossible to start
214 * more than 2^64 tasks during the lifetime of a process).
216 static GNUNET_SCHEDULER_TaskIdentifier last_id;
219 * Highest number so that all tasks with smaller identifiers
220 * have already completed. Also the lowest number of a task
221 * still waiting to be executed.
223 static GNUNET_SCHEDULER_TaskIdentifier lowest_pending_id;
226 * Number of tasks on the ready list.
228 static unsigned int ready_count;
231 * How many tasks have we run so far?
233 static unsigned long long tasks_run;
236 * Priority of the task running right now. Only
237 * valid while a task is running.
239 static enum GNUNET_SCHEDULER_Priority current_priority;
242 * Priority of the highest task added in the current select
245 static enum GNUNET_SCHEDULER_Priority max_priority_added;
248 * Value of the 'lifeness' flag for the current task.
250 static int current_lifeness;
253 * Function to use as a select() in the scheduler.
254 * If NULL, we use GNUNET_NETWORK_socket_select ().
256 static GNUNET_SCHEDULER_select scheduler_select;
259 * Closure for 'scheduler_select'.
261 static void *scheduler_select_cls;
264 * Sets the select function to use in the scheduler (scheduler_select).
266 * @param new_select new select function to use
267 * @param new_select_cls closure for 'new_select'
268 * @return previously used select function, NULL for default
271 GNUNET_SCHEDULER_set_select (GNUNET_SCHEDULER_select new_select,
272 void *new_select_cls)
274 scheduler_select = new_select;
275 scheduler_select_cls = new_select_cls;
280 * Check that the given priority is legal (and return it).
282 * @param p priority value to check
283 * @return p on success, 0 on error
285 static enum GNUNET_SCHEDULER_Priority
286 check_priority (enum GNUNET_SCHEDULER_Priority p)
288 if ((p >= 0) && (p < GNUNET_SCHEDULER_PRIORITY_COUNT))
291 return 0; /* make compiler happy */
296 * Is a task with this identifier still pending? Also updates
297 * "lowest_pending_id" as a side-effect (for faster checks in the
298 * future), but only if the return value is "GNUNET_NO" (and
299 * the "lowest_pending_id" check failed).
301 * @param id which task are we checking for
302 * @return GNUNET_YES if so, GNUNET_NO if not
305 is_pending (GNUNET_SCHEDULER_TaskIdentifier id)
308 enum GNUNET_SCHEDULER_Priority p;
309 GNUNET_SCHEDULER_TaskIdentifier min;
311 if (id < lowest_pending_id)
313 min = -1; /* maximum value */
323 pos = pending_timeout;
332 for (p = 0; p < GNUNET_SCHEDULER_PRIORITY_COUNT; p++)
344 lowest_pending_id = min;
350 * Update all sets and timeout for select.
352 * @param rs read-set, set to all FDs we would like to read (updated)
353 * @param ws write-set, set to all FDs we would like to write (updated)
354 * @param timeout next timeout (updated)
357 update_sets (struct GNUNET_NETWORK_FDSet *rs, struct GNUNET_NETWORK_FDSet *ws,
358 struct GNUNET_TIME_Relative *timeout)
361 struct GNUNET_TIME_Absolute now;
362 struct GNUNET_TIME_Relative to;
364 now = GNUNET_TIME_absolute_get ();
365 pos = pending_timeout;
368 to = GNUNET_TIME_absolute_get_difference (now, pos->timeout);
369 if (timeout->rel_value > to.rel_value)
371 if (pos->reason != 0)
372 *timeout = GNUNET_TIME_UNIT_ZERO;
377 if ((pos->prereq_id != GNUNET_SCHEDULER_NO_TASK) &&
378 (GNUNET_YES == is_pending (pos->prereq_id)))
383 if (pos->timeout.abs_value != GNUNET_TIME_UNIT_FOREVER_ABS.abs_value)
385 to = GNUNET_TIME_absolute_get_difference (now, pos->timeout);
386 if (timeout->rel_value > to.rel_value)
389 if (pos->read_fd != -1)
390 GNUNET_NETWORK_fdset_set_native (rs, pos->read_fd);
391 if (pos->write_fd != -1)
392 GNUNET_NETWORK_fdset_set_native (ws, pos->write_fd);
393 if (pos->read_set != NULL)
394 GNUNET_NETWORK_fdset_add (rs, pos->read_set);
395 if (pos->write_set != NULL)
396 GNUNET_NETWORK_fdset_add (ws, pos->write_set);
397 if (pos->reason != 0)
398 *timeout = GNUNET_TIME_UNIT_ZERO;
405 * Check if the ready set overlaps with the set we want to have ready.
406 * If so, update the want set (set all FDs that are ready). If not,
409 * @param ready set that is ready
410 * @param want set that we want to be ready
411 * @return GNUNET_YES if there was some overlap
414 set_overlaps (const struct GNUNET_NETWORK_FDSet *ready,
415 struct GNUNET_NETWORK_FDSet *want)
417 if ((NULL == want) || (NULL == ready))
419 if (GNUNET_NETWORK_fdset_overlap (ready, want))
421 /* copy all over (yes, there maybe unrelated bits,
422 * but this should not hurt well-written clients) */
423 GNUNET_NETWORK_fdset_copy (want, ready);
431 * Check if the given task is eligible to run now.
432 * Also set the reason why it is eligible.
434 * @param task task to check if it is ready
435 * @param now the current time
436 * @param rs set of FDs ready for reading
437 * @param ws set of FDs ready for writing
438 * @return GNUNET_YES if we can run it, GNUNET_NO if not.
441 is_ready (struct Task *task, struct GNUNET_TIME_Absolute now,
442 const struct GNUNET_NETWORK_FDSet *rs,
443 const struct GNUNET_NETWORK_FDSet *ws)
445 enum GNUNET_SCHEDULER_Reason reason;
447 reason = task->reason;
448 if (now.abs_value >= task->timeout.abs_value)
449 reason |= GNUNET_SCHEDULER_REASON_TIMEOUT;
450 if ((0 == (reason & GNUNET_SCHEDULER_REASON_READ_READY)) &&
451 (((task->read_fd != -1) &&
452 (GNUNET_YES == GNUNET_NETWORK_fdset_test_native (rs, task->read_fd))) ||
453 (set_overlaps (rs, task->read_set))))
454 reason |= GNUNET_SCHEDULER_REASON_READ_READY;
455 if ((0 == (reason & GNUNET_SCHEDULER_REASON_WRITE_READY)) &&
456 (((task->write_fd != -1) &&
457 (GNUNET_YES == GNUNET_NETWORK_fdset_test_native (ws, task->write_fd)))
458 || (set_overlaps (ws, task->write_set))))
459 reason |= GNUNET_SCHEDULER_REASON_WRITE_READY;
461 return GNUNET_NO; /* not ready */
462 if (task->prereq_id != GNUNET_SCHEDULER_NO_TASK)
464 if (GNUNET_YES == is_pending (task->prereq_id))
466 task->reason = reason;
467 return GNUNET_NO; /* prereq waiting */
469 reason |= GNUNET_SCHEDULER_REASON_PREREQ_DONE;
471 task->reason = reason;
477 * Put a task that is ready for execution into the ready queue.
479 * @param task task ready for execution
482 queue_ready_task (struct Task *task)
484 enum GNUNET_SCHEDULER_Priority p = task->priority;
486 if (0 != (task->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
487 p = GNUNET_SCHEDULER_PRIORITY_SHUTDOWN;
488 task->next = ready[check_priority (p)];
489 ready[check_priority (p)] = task;
495 * Check which tasks are ready and move them
496 * to the respective ready queue.
498 * @param rs FDs ready for reading
499 * @param ws FDs ready for writing
502 check_ready (const struct GNUNET_NETWORK_FDSet *rs,
503 const struct GNUNET_NETWORK_FDSet *ws)
508 struct GNUNET_TIME_Absolute now;
510 now = GNUNET_TIME_absolute_get ();
512 pos = pending_timeout;
516 if (now.abs_value >= pos->timeout.abs_value)
517 pos->reason |= GNUNET_SCHEDULER_REASON_TIMEOUT;
518 if (0 == pos->reason)
520 pending_timeout = next;
521 if (pending_timeout_last == pos)
522 pending_timeout_last = NULL;
523 queue_ready_task (pos);
530 LOG (GNUNET_ERROR_TYPE_DEBUG, "Checking readiness of task: %llu / %p\n",
531 pos->id, pos->callback_cls);
534 if (GNUNET_YES == is_ready (pos, now, rs, ws))
540 queue_ready_task (pos);
551 * Request the shutdown of a scheduler. Marks all currently
552 * pending tasks as ready because of shutdown. This will
553 * cause all tasks to run (as soon as possible, respecting
554 * priorities and prerequisite tasks). Note that tasks
555 * scheduled AFTER this call may still be delayed arbitrarily.
558 GNUNET_SCHEDULER_shutdown ()
563 pos = pending_timeout;
566 pos->reason |= GNUNET_SCHEDULER_REASON_SHUTDOWN;
567 /* we don't move the task into the ready queue yet; check_ready
568 * will do that later, possibly adding additional
569 * readiness-factors */
575 pos->reason |= GNUNET_SCHEDULER_REASON_SHUTDOWN;
576 /* we don't move the task into the ready queue yet; check_ready
577 * will do that later, possibly adding additional
578 * readiness-factors */
581 for (i = 0; i < GNUNET_SCHEDULER_PRIORITY_COUNT; i++)
586 pos->reason |= GNUNET_SCHEDULER_REASON_SHUTDOWN;
587 /* we don't move the task into the ready queue yet; check_ready
588 * will do that later, possibly adding additional
589 * readiness-factors */
597 * Destroy a task (release associated resources)
599 * @param t task to destroy
602 destroy_task (struct Task *t)
604 if (NULL != t->read_set)
605 GNUNET_NETWORK_fdset_destroy (t->read_set);
606 if (NULL != t->write_set)
607 GNUNET_NETWORK_fdset_destroy (t->write_set);
609 GNUNET_free (t->backtrace_strings);
616 * Run at least one task in the highest-priority queue that is not
617 * empty. Keep running tasks until we are either no longer running
618 * "URGENT" tasks or until we have at least one "pending" task (which
619 * may become ready, hence we should select on it). Naturally, if
620 * there are no more ready tasks, we also return.
622 * @param rs FDs ready for reading
623 * @param ws FDs ready for writing
626 run_ready (struct GNUNET_NETWORK_FDSet *rs, struct GNUNET_NETWORK_FDSet *ws)
628 enum GNUNET_SCHEDULER_Priority p;
630 struct GNUNET_SCHEDULER_TaskContext tc;
632 max_priority_added = GNUNET_SCHEDULER_PRIORITY_KEEP;
635 if (ready_count == 0)
637 GNUNET_assert (ready[GNUNET_SCHEDULER_PRIORITY_KEEP] == NULL);
638 /* yes, p>0 is correct, 0 is "KEEP" which should
639 * always be an empty queue (see assertion)! */
640 for (p = GNUNET_SCHEDULER_PRIORITY_COUNT - 1; p > 0; p--)
646 GNUNET_assert (pos != NULL); /* ready_count wrong? */
647 ready[p] = pos->next;
649 if (current_priority != pos->priority)
651 current_priority = pos->priority;
652 (void) GNUNET_OS_set_process_priority (GNUNET_OS_process_current (),
655 current_lifeness = pos->lifeness;
658 if (GNUNET_TIME_absolute_get_duration (pos->start_time).rel_value >
659 DELAY_THRESHOLD.rel_value)
661 LOG (GNUNET_ERROR_TYPE_ERROR, "Task %llu took %llums to be scheduled\n",
664 GNUNET_TIME_absolute_get_duration (pos->start_time).rel_value);
667 tc.reason = pos->reason;
668 tc.read_ready = (pos->read_set == NULL) ? rs : pos->read_set;
669 if ((pos->read_fd != -1) &&
670 (0 != (pos->reason & GNUNET_SCHEDULER_REASON_READ_READY)))
671 GNUNET_NETWORK_fdset_set_native (rs, pos->read_fd);
672 tc.write_ready = (pos->write_set == NULL) ? ws : pos->write_set;
673 if ((pos->write_fd != -1) &&
674 (0 != (pos->reason & GNUNET_SCHEDULER_REASON_WRITE_READY)))
675 GNUNET_NETWORK_fdset_set_native (ws, pos->write_fd);
676 if (((tc.reason & GNUNET_SCHEDULER_REASON_WRITE_READY) != 0) &&
677 (pos->write_fd != -1) &&
678 (!GNUNET_NETWORK_fdset_test_native (ws, pos->write_fd)))
679 GNUNET_abort (); // added to ready in previous select loop!
681 LOG (GNUNET_ERROR_TYPE_DEBUG, "Running task: %llu / %p\n", pos->id,
684 pos->callback (pos->callback_cls, &tc);
688 for (i = 0; i < pos->num_backtrace_strings; i++)
689 LOG (GNUNET_ERROR_TYPE_ERROR, "Task %llu trace %d: %s\n", pos->id, i,
690 pos->backtrace_strings[i]);
696 while ((pending == NULL) || (p >= max_priority_added));
700 * Pipe used to communicate shutdown via signal.
702 static struct GNUNET_DISK_PipeHandle *shutdown_pipe_handle;
705 * Process ID of this process at the time we installed the various
711 * Signal handler called for SIGPIPE.
721 * Signal handler called for signals that should cause us to shutdown.
724 sighandler_shutdown ()
727 int old_errno = errno; /* backup errno */
729 if (getpid () != my_pid)
730 exit (1); /* we have fork'ed since the signal handler was created,
731 * ignore the signal, see https://gnunet.org/vfork discussion */
732 GNUNET_DISK_file_write (GNUNET_DISK_pipe_handle
733 (shutdown_pipe_handle, GNUNET_DISK_PIPE_END_WRITE),
740 * Check if the system is still life. Trigger shutdown if we
741 * have tasks, but none of them give us lifeness.
743 * @return GNUNET_OK to continue the main loop,
753 for (t = pending; NULL != t; t = t->next)
754 if (t->lifeness == GNUNET_YES)
756 for (t = pending_timeout; NULL != t; t = t->next)
757 if (t->lifeness == GNUNET_YES)
759 if ((NULL != pending) || (NULL != pending_timeout))
761 GNUNET_SCHEDULER_shutdown ();
769 * Initialize and run scheduler. This function will return when all
770 * tasks have completed. On systems with signals, receiving a SIGTERM
771 * (and other similar signals) will cause "GNUNET_SCHEDULER_shutdown"
772 * to be run after the active task is complete. As a result, SIGTERM
773 * causes all active tasks to be scheduled with reason
774 * "GNUNET_SCHEDULER_REASON_SHUTDOWN". (However, tasks added
775 * afterwards will execute normally!). Note that any particular signal
776 * will only shut down one scheduler; applications should always only
777 * create a single scheduler.
779 * @param task task to run immediately
780 * @param task_cls closure of task
783 GNUNET_SCHEDULER_run (GNUNET_SCHEDULER_Task task, void *task_cls)
785 struct GNUNET_NETWORK_FDSet *rs;
786 struct GNUNET_NETWORK_FDSet *ws;
787 struct GNUNET_TIME_Relative timeout;
789 struct GNUNET_SIGNAL_Context *shc_int;
790 struct GNUNET_SIGNAL_Context *shc_term;
793 struct GNUNET_SIGNAL_Context *shc_quit;
794 struct GNUNET_SIGNAL_Context *shc_hup;
795 struct GNUNET_SIGNAL_Context *shc_pipe;
797 unsigned long long last_tr;
798 unsigned int busy_wait_warning;
799 const struct GNUNET_DISK_FileHandle *pr;
802 GNUNET_assert (active_task == NULL);
803 rs = GNUNET_NETWORK_fdset_create ();
804 ws = GNUNET_NETWORK_fdset_create ();
805 GNUNET_assert (shutdown_pipe_handle == NULL);
806 shutdown_pipe_handle = GNUNET_DISK_pipe (GNUNET_NO, GNUNET_NO, GNUNET_NO, GNUNET_NO);
807 GNUNET_assert (shutdown_pipe_handle != NULL);
808 pr = GNUNET_DISK_pipe_handle (shutdown_pipe_handle,
809 GNUNET_DISK_PIPE_END_READ);
810 GNUNET_assert (pr != NULL);
812 shc_int = GNUNET_SIGNAL_handler_install (SIGINT, &sighandler_shutdown);
813 shc_term = GNUNET_SIGNAL_handler_install (SIGTERM, &sighandler_shutdown);
815 shc_pipe = GNUNET_SIGNAL_handler_install (SIGPIPE, &sighandler_pipe);
816 shc_quit = GNUNET_SIGNAL_handler_install (SIGQUIT, &sighandler_shutdown);
817 shc_hup = GNUNET_SIGNAL_handler_install (SIGHUP, &sighandler_shutdown);
819 current_priority = GNUNET_SCHEDULER_PRIORITY_DEFAULT;
820 current_lifeness = GNUNET_YES;
821 GNUNET_SCHEDULER_add_continuation (task, task_cls,
822 GNUNET_SCHEDULER_REASON_STARTUP);
823 #if ENABLE_WINDOWS_WORKAROUNDS
824 active_task = (void *) (long) -1; /* force passing of sanity check */
825 GNUNET_SCHEDULER_add_now_with_lifeness (GNUNET_NO,
826 &GNUNET_OS_install_parent_control_handler,
831 busy_wait_warning = 0;
832 while (GNUNET_OK == check_lifeness ())
834 GNUNET_NETWORK_fdset_zero (rs);
835 GNUNET_NETWORK_fdset_zero (ws);
836 timeout = GNUNET_TIME_UNIT_FOREVER_REL;
837 update_sets (rs, ws, &timeout);
838 GNUNET_NETWORK_fdset_handle_set (rs, pr);
841 /* no blocking, more work already ready! */
842 timeout = GNUNET_TIME_UNIT_ZERO;
844 if (NULL == scheduler_select)
845 ret = GNUNET_NETWORK_socket_select (rs, ws, NULL, timeout);
847 ret = scheduler_select (scheduler_select_cls, rs, ws, NULL, timeout);
848 if (ret == GNUNET_SYSERR)
853 LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "select");
858 snprintf (lsof, sizeof (lsof), "lsof -p %d", getpid ());
861 if (0 != system (lsof))
862 LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "system");
868 if ((ret == 0) && (timeout.rel_value == 0) && (busy_wait_warning > 16))
870 LOG (GNUNET_ERROR_TYPE_WARNING, _("Looks like we're busy waiting...\n"));
871 sleep (1); /* mitigate */
873 check_ready (rs, ws);
875 if (GNUNET_NETWORK_fdset_handle_isset (rs, pr))
877 /* consume the signal */
878 GNUNET_DISK_file_read (pr, &c, sizeof (c));
879 /* mark all active tasks as ready due to shutdown */
880 GNUNET_SCHEDULER_shutdown ();
882 if (last_tr == tasks_run)
889 busy_wait_warning = 0;
892 GNUNET_SIGNAL_handler_uninstall (shc_int);
893 GNUNET_SIGNAL_handler_uninstall (shc_term);
895 GNUNET_SIGNAL_handler_uninstall (shc_pipe);
896 GNUNET_SIGNAL_handler_uninstall (shc_quit);
897 GNUNET_SIGNAL_handler_uninstall (shc_hup);
899 GNUNET_DISK_pipe_close (shutdown_pipe_handle);
900 shutdown_pipe_handle = NULL;
901 GNUNET_NETWORK_fdset_destroy (rs);
902 GNUNET_NETWORK_fdset_destroy (ws);
907 * Obtain the reason code for why the current task was
908 * started. Will return the same value as
909 * the GNUNET_SCHEDULER_TaskContext's reason field.
911 * @return reason(s) why the current task is run
913 enum GNUNET_SCHEDULER_Reason
914 GNUNET_SCHEDULER_get_reason ()
916 GNUNET_assert (active_task != NULL);
917 return active_task->reason;
922 * Get information about the current load of this scheduler. Use this
923 * function to determine if an elective task should be added or simply
924 * dropped (if the decision should be made based on the number of
925 * tasks ready to run).
927 * @param p priority level to look at
928 * @return number of tasks pending right now
931 GNUNET_SCHEDULER_get_load (enum GNUNET_SCHEDULER_Priority p)
936 GNUNET_assert (active_task != NULL);
937 if (p == GNUNET_SCHEDULER_PRIORITY_COUNT)
939 if (p == GNUNET_SCHEDULER_PRIORITY_KEEP)
940 p = current_priority;
942 pos = ready[check_priority (p)];
953 * Cancel the task with the specified identifier.
954 * The task must not yet have run.
956 * @param task id of the task to cancel
957 * @return original closure of the task
960 GNUNET_SCHEDULER_cancel (GNUNET_SCHEDULER_TaskIdentifier task)
964 enum GNUNET_SCHEDULER_Priority p;
968 GNUNET_assert (active_task != NULL);
991 if (pending_timeout_last == t)
992 pending_timeout_last = NULL;
998 if (p >= GNUNET_SCHEDULER_PRIORITY_COUNT)
1000 LOG (GNUNET_ERROR_TYPE_ERROR, _("Attempt to cancel dead task %llu!\n"),
1001 (unsigned long long) task);
1027 pending_timeout = t->next;
1037 prev->next = t->next;
1039 ret = t->callback_cls;
1041 LOG (GNUNET_ERROR_TYPE_DEBUG, "Canceling task: %llu / %p\n", task,
1050 * Continue the current execution with the given function. This is
1051 * similar to the other "add" functions except that there is no delay
1052 * and the reason code can be specified.
1054 * @param task main function of the task
1055 * @param task_cls closure for 'main'
1056 * @param reason reason for task invocation
1057 * @param priority priority to use for the task
1060 GNUNET_SCHEDULER_add_continuation_with_priority (GNUNET_SCHEDULER_Task task, void *task_cls,
1061 enum GNUNET_SCHEDULER_Reason reason,
1062 enum GNUNET_SCHEDULER_Priority priority)
1067 void *backtrace_array[50];
1070 GNUNET_assert (NULL != task);
1071 GNUNET_assert ((active_task != NULL) ||
1072 (reason == GNUNET_SCHEDULER_REASON_STARTUP));
1073 t = GNUNET_malloc (sizeof (struct Task));
1075 t->num_backtrace_strings = backtrace (backtrace_array, 50);
1076 t->backtrace_strings =
1077 backtrace_symbols (backtrace_array, t->num_backtrace_strings);
1082 t->callback_cls = task_cls;
1085 t->start_time = GNUNET_TIME_absolute_get ();
1088 t->priority = priority;
1089 t->lifeness = current_lifeness;
1091 LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding continuation task: %llu / %p\n", t->id,
1094 queue_ready_task (t);
1099 * Continue the current execution with the given function. This is
1100 * similar to the other "add" functions except that there is no delay
1101 * and the reason code can be specified.
1103 * @param task main function of the task
1104 * @param task_cls closure for 'main'
1105 * @param reason reason for task invocation
1108 GNUNET_SCHEDULER_add_continuation (GNUNET_SCHEDULER_Task task, void *task_cls,
1109 enum GNUNET_SCHEDULER_Reason reason)
1111 GNUNET_SCHEDULER_add_continuation_with_priority (task, task_cls,
1113 GNUNET_SCHEDULER_PRIORITY_DEFAULT);
1118 * Schedule a new task to be run after the specified prerequisite task
1119 * has completed. It will be run with the DEFAULT priority.
1121 * @param prerequisite_task run this task after the task with the given
1122 * task identifier completes (and any of our other
1123 * conditions, such as delay, read or write-readiness
1124 * are satisfied). Use GNUNET_SCHEDULER_NO_TASK to not have any dependency
1125 * on completion of other tasks (this will cause the task to run as
1126 * soon as possible).
1127 * @param task main function of the task
1128 * @param task_cls closure of task
1129 * @return unique task identifier for the job
1130 * only valid until "task" is started!
1132 GNUNET_SCHEDULER_TaskIdentifier
1133 GNUNET_SCHEDULER_add_after (GNUNET_SCHEDULER_TaskIdentifier prerequisite_task,
1134 GNUNET_SCHEDULER_Task task, void *task_cls)
1136 return GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1137 prerequisite_task, GNUNET_TIME_UNIT_ZERO,
1138 NULL, NULL, task, task_cls);
1143 * Schedule a new task to be run with a specified priority.
1145 * @param prio how important is the new task?
1146 * @param task main function of the task
1147 * @param task_cls closure of task
1148 * @return unique task identifier for the job
1149 * only valid until "task" is started!
1151 GNUNET_SCHEDULER_TaskIdentifier
1152 GNUNET_SCHEDULER_add_with_priority (enum GNUNET_SCHEDULER_Priority prio,
1153 GNUNET_SCHEDULER_Task task, void *task_cls)
1155 return GNUNET_SCHEDULER_add_select (prio, GNUNET_SCHEDULER_NO_TASK,
1156 GNUNET_TIME_UNIT_ZERO, NULL, NULL, task,
1163 * Schedule a new task to be run with a specified delay. The task
1164 * will be scheduled for execution once the delay has expired.
1166 * @param delay when should this operation time out? Use
1167 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1168 * @param priority priority to use for the task
1169 * @param task main function of the task
1170 * @param task_cls closure of task
1171 * @return unique task identifier for the job
1172 * only valid until "task" is started!
1174 GNUNET_SCHEDULER_TaskIdentifier
1175 GNUNET_SCHEDULER_add_delayed_with_priority (struct GNUNET_TIME_Relative delay,
1176 enum GNUNET_SCHEDULER_Priority priority,
1177 GNUNET_SCHEDULER_Task task, void *task_cls)
1184 void *backtrace_array[MAX_TRACE_DEPTH];
1187 GNUNET_assert (active_task != NULL);
1188 GNUNET_assert (NULL != task);
1189 t = GNUNET_malloc (sizeof (struct Task));
1191 t->callback_cls = task_cls;
1193 t->num_backtrace_strings = backtrace (backtrace_array, MAX_TRACE_DEPTH);
1194 t->backtrace_strings =
1195 backtrace_symbols (backtrace_array, t->num_backtrace_strings);
1201 t->start_time = GNUNET_TIME_absolute_get ();
1203 t->timeout = GNUNET_TIME_relative_to_absolute (delay);
1204 t->priority = priority;
1205 t->lifeness = current_lifeness;
1206 /* try tail first (optimization in case we are
1207 * appending to a long list of tasks with timeouts) */
1208 prev = pending_timeout_last;
1211 if (prev->timeout.abs_value > t->timeout.abs_value)
1214 pos = prev->next; /* heuristic success! */
1218 /* heuristic failed, do traversal of timeout list */
1219 pos = pending_timeout;
1221 while ((pos != NULL) &&
1222 ((pos->timeout.abs_value <= t->timeout.abs_value) ||
1223 (pos->reason != 0)))
1229 pending_timeout = t;
1233 /* hyper-optimization... */
1234 pending_timeout_last = t;
1237 LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding task: %llu / %p\n", t->id,
1243 for (i = 0; i < t->num_backtrace_strings; i++)
1244 LOG (GNUNET_ERROR_TYPE_DEBUG, "Task %llu trace %d: %s\n", t->id, i,
1245 t->backtrace_strings[i]);
1252 * Schedule a new task to be run with a specified delay. The task
1253 * will be scheduled for execution once the delay has expired. It
1254 * will be run with the DEFAULT priority.
1256 * @param delay when should this operation time out? Use
1257 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1258 * @param task main function of the task
1259 * @param task_cls closure of task
1260 * @return unique task identifier for the job
1261 * only valid until "task" is started!
1263 GNUNET_SCHEDULER_TaskIdentifier
1264 GNUNET_SCHEDULER_add_delayed (struct GNUNET_TIME_Relative delay,
1265 GNUNET_SCHEDULER_Task task, void *task_cls)
1267 return GNUNET_SCHEDULER_add_delayed_with_priority (delay,
1268 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1274 * Schedule a new task to be run as soon as possible. The task
1275 * will be run with the DEFAULT priority.
1277 * @param task main function of the task
1278 * @param task_cls closure of task
1279 * @return unique task identifier for the job
1280 * only valid until "task" is started!
1282 GNUNET_SCHEDULER_TaskIdentifier
1283 GNUNET_SCHEDULER_add_now (GNUNET_SCHEDULER_Task task, void *task_cls)
1285 return GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_ZERO, task, task_cls);
1290 * Schedule a new task to be run as soon as possible with the
1291 * (transitive) ignore-shutdown flag either explicitly set or
1292 * explicitly enabled. This task (and all tasks created from it,
1293 * other than by another call to this function) will either count or
1294 * not count for the 'lifeness' of the process. This API is only
1295 * useful in a few special cases.
1297 * @param lifeness GNUNET_YES if the task counts for lifeness, GNUNET_NO if not.
1298 * @param task main function of the task
1299 * @param task_cls closure of task
1300 * @return unique task identifier for the job
1301 * only valid until "task" is started!
1303 GNUNET_SCHEDULER_TaskIdentifier
1304 GNUNET_SCHEDULER_add_now_with_lifeness (int lifeness,
1305 GNUNET_SCHEDULER_Task task,
1308 GNUNET_SCHEDULER_TaskIdentifier ret;
1311 GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1312 GNUNET_SCHEDULER_NO_TASK,
1313 GNUNET_TIME_UNIT_ZERO, NULL, NULL, task,
1315 GNUNET_assert (pending->id == ret);
1316 pending->lifeness = lifeness;
1322 * Schedule a new task to be run with a specified delay or when any of
1323 * the specified file descriptor sets is ready. The delay can be used
1324 * as a timeout on the socket(s) being ready. The task will be
1325 * scheduled for execution once either the delay has expired or any of
1326 * the socket operations is ready. This is the most general
1327 * function of the "add" family. Note that the "prerequisite_task"
1328 * must be satisfied in addition to any of the other conditions. In
1329 * other words, the task will be started when
1331 * (prerequisite-run)
1335 * || shutdown-active )
1338 * @param delay how long should we wait? Use GNUNET_TIME_UNIT_FOREVER_REL for "forever",
1339 * which means that the task will only be run after we receive SIGTERM
1340 * @param priority priority to use
1341 * @param rfd file descriptor we want to read (can be -1)
1342 * @param wfd file descriptors we want to write (can be -1)
1343 * @param task main function of the task
1344 * @param task_cls closure of task
1345 * @return unique task identifier for the job
1346 * only valid until "task" is started!
1349 static GNUNET_SCHEDULER_TaskIdentifier
1350 add_without_sets (struct GNUNET_TIME_Relative delay,
1351 enum GNUNET_SCHEDULER_Priority priority,
1353 GNUNET_SCHEDULER_Task task, void *task_cls)
1358 void *backtrace_array[MAX_TRACE_DEPTH];
1361 GNUNET_assert (active_task != NULL);
1362 GNUNET_assert (NULL != task);
1363 t = GNUNET_malloc (sizeof (struct Task));
1365 t->callback_cls = task_cls;
1367 t->num_backtrace_strings = backtrace (backtrace_array, MAX_TRACE_DEPTH);
1368 t->backtrace_strings =
1369 backtrace_symbols (backtrace_array, t->num_backtrace_strings);
1374 int flags = fcntl (rfd, F_GETFD);
1376 if ((flags == -1) && (errno == EBADF))
1378 LOG (GNUNET_ERROR_TYPE_ERROR, "Got invalid file descriptor %d!\n", rfd);
1382 for (i = 0; i < t->num_backtrace_strings; i++)
1383 LOG (GNUNET_ERROR_TYPE_DEBUG, "Trace: %s\n", t->backtrace_strings[i]);
1390 int flags = fcntl (wfd, F_GETFD);
1392 if (flags == -1 && errno == EBADF)
1394 LOG (GNUNET_ERROR_TYPE_ERROR, "Got invalid file descriptor %d!\n", wfd);
1398 for (i = 0; i < t->num_backtrace_strings; i++)
1399 LOG (GNUNET_ERROR_TYPE_DEBUG, "Trace: %s\n", t->backtrace_strings[i]);
1406 GNUNET_assert (wfd >= -1);
1410 t->start_time = GNUNET_TIME_absolute_get ();
1412 t->prereq_id = GNUNET_SCHEDULER_NO_TASK;
1413 t->timeout = GNUNET_TIME_relative_to_absolute (delay);
1414 t->priority = check_priority ((priority == GNUNET_SCHEDULER_PRIORITY_KEEP) ? current_priority : priority);
1415 t->lifeness = current_lifeness;
1418 max_priority_added = GNUNET_MAX (max_priority_added, t->priority);
1420 LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding task: %llu / %p\n", t->id,
1426 for (i = 0; i < t->num_backtrace_strings; i++)
1427 LOG (GNUNET_ERROR_TYPE_DEBUG, "Task %llu trace %d: %s\n", t->id, i,
1428 t->backtrace_strings[i]);
1437 * Schedule a new task to be run with a specified delay or when the
1438 * specified file descriptor is ready for reading. The delay can be
1439 * used as a timeout on the socket being ready. The task will be
1440 * scheduled for execution once either the delay has expired or the
1441 * socket operation is ready. It will be run with the DEFAULT priority.
1443 * @param delay when should this operation time out? Use
1444 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1445 * @param rfd read file-descriptor
1446 * @param task main function of the task
1447 * @param task_cls closure of task
1448 * @return unique task identifier for the job
1449 * only valid until "task" is started!
1451 GNUNET_SCHEDULER_TaskIdentifier
1452 GNUNET_SCHEDULER_add_read_net (struct GNUNET_TIME_Relative delay,
1453 struct GNUNET_NETWORK_Handle *rfd,
1454 GNUNET_SCHEDULER_Task task, void *task_cls)
1457 struct GNUNET_NETWORK_FDSet *rs;
1458 GNUNET_SCHEDULER_TaskIdentifier ret;
1460 GNUNET_assert (rfd != NULL);
1461 rs = GNUNET_NETWORK_fdset_create ();
1462 GNUNET_NETWORK_fdset_set (rs, rfd);
1464 GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1465 GNUNET_SCHEDULER_NO_TASK, delay, rs, NULL,
1467 GNUNET_NETWORK_fdset_destroy (rs);
1470 return add_without_sets (delay,
1471 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1472 GNUNET_NETWORK_get_fd (rfd), -1, task,
1479 * Schedule a new task to be run with a specified delay or when the
1480 * specified file descriptor is ready for writing. The delay can be
1481 * used as a timeout on the socket being ready. The task will be
1482 * scheduled for execution once either the delay has expired or the
1483 * socket operation is ready. It will be run with the priority of
1486 * @param delay when should this operation time out? Use
1487 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1488 * @param wfd write file-descriptor
1489 * @param task main function of the task
1490 * @param task_cls closure of task
1491 * @return unique task identifier for the job
1492 * only valid until "task" is started!
1494 GNUNET_SCHEDULER_TaskIdentifier
1495 GNUNET_SCHEDULER_add_write_net (struct GNUNET_TIME_Relative delay,
1496 struct GNUNET_NETWORK_Handle *wfd,
1497 GNUNET_SCHEDULER_Task task, void *task_cls)
1500 struct GNUNET_NETWORK_FDSet *ws;
1501 GNUNET_SCHEDULER_TaskIdentifier ret;
1503 GNUNET_assert (wfd != NULL);
1504 ws = GNUNET_NETWORK_fdset_create ();
1505 GNUNET_NETWORK_fdset_set (ws, wfd);
1507 GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1508 GNUNET_SCHEDULER_NO_TASK, delay, NULL, ws,
1510 GNUNET_NETWORK_fdset_destroy (ws);
1513 GNUNET_assert (GNUNET_NETWORK_get_fd (wfd) >= 0);
1514 return add_without_sets (delay,
1515 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1516 -1, GNUNET_NETWORK_get_fd (wfd), task,
1523 * Schedule a new task to be run with a specified delay or when the
1524 * specified file descriptor is ready for reading. The delay can be
1525 * used as a timeout on the socket being ready. The task will be
1526 * scheduled for execution once either the delay has expired or the
1527 * socket operation is ready. It will be run with the DEFAULT priority.
1529 * @param delay when should this operation time out? Use
1530 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1531 * @param rfd read file-descriptor
1532 * @param task main function of the task
1533 * @param task_cls closure of task
1534 * @return unique task identifier for the job
1535 * only valid until "task" is started!
1537 GNUNET_SCHEDULER_TaskIdentifier
1538 GNUNET_SCHEDULER_add_read_file (struct GNUNET_TIME_Relative delay,
1539 const struct GNUNET_DISK_FileHandle *rfd,
1540 GNUNET_SCHEDULER_Task task, void *task_cls)
1543 struct GNUNET_NETWORK_FDSet *rs;
1544 GNUNET_SCHEDULER_TaskIdentifier ret;
1546 GNUNET_assert (rfd != NULL);
1547 rs = GNUNET_NETWORK_fdset_create ();
1548 GNUNET_NETWORK_fdset_handle_set (rs, rfd);
1550 GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1551 GNUNET_SCHEDULER_NO_TASK, delay, rs, NULL,
1553 GNUNET_NETWORK_fdset_destroy (rs);
1558 GNUNET_DISK_internal_file_handle_ (rfd, &fd, sizeof (int));
1559 return add_without_sets (delay,
1560 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1561 fd, -1, task, task_cls);
1568 * Schedule a new task to be run with a specified delay or when the
1569 * specified file descriptor is ready for writing. The delay can be
1570 * used as a timeout on the socket being ready. The task will be
1571 * scheduled for execution once either the delay has expired or the
1572 * socket operation is ready. It will be run with the DEFAULT priority.
1574 * @param delay when should this operation time out? Use
1575 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1576 * @param wfd write file-descriptor
1577 * @param task main function of the task
1578 * @param task_cls closure of task
1579 * @return unique task identifier for the job
1580 * only valid until "task" is started!
1582 GNUNET_SCHEDULER_TaskIdentifier
1583 GNUNET_SCHEDULER_add_write_file (struct GNUNET_TIME_Relative delay,
1584 const struct GNUNET_DISK_FileHandle *wfd,
1585 GNUNET_SCHEDULER_Task task, void *task_cls)
1588 struct GNUNET_NETWORK_FDSet *ws;
1589 GNUNET_SCHEDULER_TaskIdentifier ret;
1591 GNUNET_assert (wfd != NULL);
1592 ws = GNUNET_NETWORK_fdset_create ();
1593 GNUNET_NETWORK_fdset_handle_set (ws, wfd);
1595 GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1596 GNUNET_SCHEDULER_NO_TASK, delay, NULL, ws,
1598 GNUNET_NETWORK_fdset_destroy (ws);
1603 GNUNET_DISK_internal_file_handle_ (wfd, &fd, sizeof (int));
1604 GNUNET_assert (fd >= 0);
1605 return add_without_sets (delay,
1606 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
1607 -1, fd, task, task_cls);
1615 * Schedule a new task to be run with a specified delay or when any of
1616 * the specified file descriptor sets is ready. The delay can be used
1617 * as a timeout on the socket(s) being ready. The task will be
1618 * scheduled for execution once either the delay has expired or any of
1619 * the socket operations is ready. This is the most general
1620 * function of the "add" family. Note that the "prerequisite_task"
1621 * must be satisfied in addition to any of the other conditions. In
1622 * other words, the task will be started when
1624 * (prerequisite-run)
1628 * || (shutdown-active && run-on-shutdown) )
1631 * @param prio how important is this task?
1632 * @param prerequisite_task run this task after the task with the given
1633 * task identifier completes (and any of our other
1634 * conditions, such as delay, read or write-readiness
1635 * are satisfied). Use GNUNET_SCHEDULER_NO_TASK to not have any dependency
1636 * on completion of other tasks.
1637 * @param delay how long should we wait? Use GNUNET_TIME_UNIT_FOREVER_REL for "forever",
1638 * which means that the task will only be run after we receive SIGTERM
1639 * @param rs set of file descriptors we want to read (can be NULL)
1640 * @param ws set of file descriptors we want to write (can be NULL)
1641 * @param task main function of the task
1642 * @param task_cls closure of task
1643 * @return unique task identifier for the job
1644 * only valid until "task" is started!
1646 GNUNET_SCHEDULER_TaskIdentifier
1647 GNUNET_SCHEDULER_add_select (enum GNUNET_SCHEDULER_Priority prio,
1648 GNUNET_SCHEDULER_TaskIdentifier prerequisite_task,
1649 struct GNUNET_TIME_Relative delay,
1650 const struct GNUNET_NETWORK_FDSet *rs,
1651 const struct GNUNET_NETWORK_FDSet *ws,
1652 GNUNET_SCHEDULER_Task task, void *task_cls)
1657 void *backtrace_array[MAX_TRACE_DEPTH];
1660 GNUNET_assert (active_task != NULL);
1661 GNUNET_assert (NULL != task);
1662 t = GNUNET_malloc (sizeof (struct Task));
1664 t->callback_cls = task_cls;
1666 t->num_backtrace_strings = backtrace (backtrace_array, MAX_TRACE_DEPTH);
1667 t->backtrace_strings =
1668 backtrace_symbols (backtrace_array, t->num_backtrace_strings);
1674 t->read_set = GNUNET_NETWORK_fdset_create ();
1675 GNUNET_NETWORK_fdset_copy (t->read_set, rs);
1679 t->write_set = GNUNET_NETWORK_fdset_create ();
1680 GNUNET_NETWORK_fdset_copy (t->write_set, ws);
1684 t->start_time = GNUNET_TIME_absolute_get ();
1686 t->prereq_id = prerequisite_task;
1687 t->timeout = GNUNET_TIME_relative_to_absolute (delay);
1689 check_priority ((prio ==
1690 GNUNET_SCHEDULER_PRIORITY_KEEP) ? current_priority :
1692 t->lifeness = current_lifeness;
1695 max_priority_added = GNUNET_MAX (max_priority_added, t->priority);
1697 LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding task: %llu / %p\n", t->id,
1703 for (i = 0; i < t->num_backtrace_strings; i++)
1704 LOG (GNUNET_ERROR_TYPE_DEBUG, "Task %llu trace %d: %s\n", t->id, i,
1705 t->backtrace_strings[i]);
1710 /* end of scheduler.c */