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"
38 * Use lsof to generate file descriptor reports on select error?
39 * (turn off for stable releases).
41 #define USE_LSOF GNUNET_NO
44 * Obtain trace information for all scheduler calls that schedule tasks.
46 #define EXECINFO GNUNET_NO
49 * Check each file descriptor before adding
51 #define DEBUG_FDS GNUNET_EXTRA_LOGGING
54 * Depth of the traces collected via EXECINFO.
56 #define MAX_TRACE_DEPTH 50
59 #define DEBUG_TASKS GNUNET_EXTRA_LOGGING
62 * Should we figure out which tasks are delayed for a while
63 * before they are run? (Consider using in combination with EXECINFO).
65 #define PROFILE_DELAYS GNUNET_NO
68 * Task that were in the queue for longer than this are reported if
69 * PROFILE_DELAYS is active.
71 #define DELAY_THRESHOLD GNUNET_TIME_UNIT_SECONDS
74 * Linked list of pending tasks.
79 * This is a linked list.
84 * Function to run when ready.
86 GNUNET_SCHEDULER_Task callback;
89 * Closure for the callback.
94 * Set of file descriptors this task is waiting
95 * for for reading. Once ready, this is updated
96 * to reflect the set of file descriptors ready
99 struct GNUNET_NETWORK_FDSet *read_set;
102 * Set of file descriptors this task is waiting for for writing.
103 * Once ready, this is updated to reflect the set of file
104 * descriptors ready for operation.
106 struct GNUNET_NETWORK_FDSet *write_set;
109 * Unique task identifier.
111 GNUNET_SCHEDULER_TaskIdentifier id;
114 * Identifier of a prerequisite task.
116 GNUNET_SCHEDULER_TaskIdentifier prereq_id;
119 * Absolute timeout value for the task, or
120 * GNUNET_TIME_UNIT_FOREVER_ABS for "no timeout".
122 struct GNUNET_TIME_Absolute timeout;
126 * When was the task scheduled?
128 struct GNUNET_TIME_Absolute start_time;
132 * Why is the task ready? Set after task is added to ready queue.
133 * Initially set to zero. All reasons that have already been
134 * satisfied (i.e. read or write ready) will be set over time.
136 enum GNUNET_SCHEDULER_Reason reason;
141 enum GNUNET_SCHEDULER_Priority priority;
144 * Set if we only wait for reading from a single FD, otherwise -1.
149 * Set if we only wait for writing to a single FD, otherwise -1.
154 * Should the existence of this task in the queue be counted as
155 * reason to not shutdown the scheduler?
161 * Array of strings which make up a backtrace from the point when this
162 * task was scheduled (essentially, who scheduled the task?)
164 char **backtrace_strings;
167 * Size of the backtrace_strings array
169 int num_backtrace_strings;
177 * List of tasks waiting for an event.
179 static struct Task *pending;
182 * List of tasks waiting ONLY for a timeout event.
183 * Sorted by timeout (earliest first). Used so that
184 * we do not traverse the list of these tasks when
185 * building select sets (we just look at the head
186 * to determine the respective timeout ONCE).
188 static struct Task *pending_timeout;
191 * Last inserted task waiting ONLY for a timeout event.
192 * Used to (heuristically) speed up insertion.
194 static struct Task *pending_timeout_last;
197 * ID of the task that is running right now.
199 static struct Task *active_task;
202 * List of tasks ready to run right now,
203 * grouped by importance.
205 static struct Task *ready[GNUNET_SCHEDULER_PRIORITY_COUNT];
208 * Identity of the last task queued. Incremented for each task to
209 * generate a unique task ID (it is virtually impossible to start
210 * more than 2^64 tasks during the lifetime of a process).
212 static GNUNET_SCHEDULER_TaskIdentifier last_id;
215 * Highest number so that all tasks with smaller identifiers
216 * have already completed. Also the lowest number of a task
217 * still waiting to be executed.
219 static GNUNET_SCHEDULER_TaskIdentifier lowest_pending_id;
222 * Number of tasks on the ready list.
224 static unsigned int ready_count;
227 * How many tasks have we run so far?
229 static unsigned long long tasks_run;
232 * Priority of the task running right now. Only
233 * valid while a task is running.
235 static enum GNUNET_SCHEDULER_Priority current_priority;
238 * Priority of the highest task added in the current select
241 static enum GNUNET_SCHEDULER_Priority max_priority_added;
244 * Value of the 'lifeness' flag for the current task.
246 static int current_lifeness;
249 * Function to use as a select() in the scheduler.
250 * If NULL, we use GNUNET_NETWORK_socket_select ().
252 static GNUNET_SCHEDULER_select scheduler_select;
255 * Closure for 'scheduler_select'.
257 static void *scheduler_select_cls;
260 * Sets the select function to use in the scheduler (scheduler_select).
262 * @param new_select new select function to use
263 * @param new_select_cls closure for 'new_select'
264 * @return previously used select function, NULL for default
267 GNUNET_SCHEDULER_set_select (GNUNET_SCHEDULER_select new_select,
268 void *new_select_cls)
270 scheduler_select = new_select;
271 scheduler_select_cls = new_select_cls;
276 * Check that the given priority is legal (and return it).
278 * @param p priority value to check
279 * @return p on success, 0 on error
281 static enum GNUNET_SCHEDULER_Priority
282 check_priority (enum GNUNET_SCHEDULER_Priority p)
284 if ((p >= 0) && (p < GNUNET_SCHEDULER_PRIORITY_COUNT))
287 return 0; /* make compiler happy */
292 * Is a task with this identifier still pending? Also updates
293 * "lowest_pending_id" as a side-effect (for faster checks in the
294 * future), but only if the return value is "GNUNET_NO" (and
295 * the "lowest_pending_id" check failed).
297 * @param id which task are we checking for
298 * @return GNUNET_YES if so, GNUNET_NO if not
301 is_pending (GNUNET_SCHEDULER_TaskIdentifier id)
304 enum GNUNET_SCHEDULER_Priority p;
305 GNUNET_SCHEDULER_TaskIdentifier min;
307 if (id < lowest_pending_id)
309 min = -1; /* maximum value */
319 pos = pending_timeout;
328 for (p = 0; p < GNUNET_SCHEDULER_PRIORITY_COUNT; p++)
340 lowest_pending_id = min;
346 * Update all sets and timeout for select.
348 * @param rs read-set, set to all FDs we would like to read (updated)
349 * @param ws write-set, set to all FDs we would like to write (updated)
350 * @param timeout next timeout (updated)
353 update_sets (struct GNUNET_NETWORK_FDSet *rs, struct GNUNET_NETWORK_FDSet *ws,
354 struct GNUNET_TIME_Relative *timeout)
357 struct GNUNET_TIME_Absolute now;
358 struct GNUNET_TIME_Relative to;
360 now = GNUNET_TIME_absolute_get ();
361 pos = pending_timeout;
364 to = GNUNET_TIME_absolute_get_difference (now, pos->timeout);
365 if (timeout->rel_value > to.rel_value)
367 if (pos->reason != 0)
368 *timeout = GNUNET_TIME_UNIT_ZERO;
373 if ((pos->prereq_id != GNUNET_SCHEDULER_NO_TASK) &&
374 (GNUNET_YES == is_pending (pos->prereq_id)))
379 if (pos->timeout.abs_value != GNUNET_TIME_UNIT_FOREVER_ABS.abs_value)
381 to = GNUNET_TIME_absolute_get_difference (now, pos->timeout);
382 if (timeout->rel_value > to.rel_value)
385 if (pos->read_fd != -1)
386 GNUNET_NETWORK_fdset_set_native (rs, pos->read_fd);
387 if (pos->write_fd != -1)
388 GNUNET_NETWORK_fdset_set_native (ws, pos->write_fd);
389 if (pos->read_set != NULL)
390 GNUNET_NETWORK_fdset_add (rs, pos->read_set);
391 if (pos->write_set != NULL)
392 GNUNET_NETWORK_fdset_add (ws, pos->write_set);
393 if (pos->reason != 0)
394 *timeout = GNUNET_TIME_UNIT_ZERO;
401 * Check if the ready set overlaps with the set we want to have ready.
402 * If so, update the want set (set all FDs that are ready). If not,
405 * @param ready set that is ready
406 * @param want set that we want to be ready
407 * @return GNUNET_YES if there was some overlap
410 set_overlaps (const struct GNUNET_NETWORK_FDSet *ready,
411 struct GNUNET_NETWORK_FDSet *want)
413 if ((NULL == want) || (NULL == ready))
415 if (GNUNET_NETWORK_fdset_overlap (ready, want))
417 /* copy all over (yes, there maybe unrelated bits,
418 * but this should not hurt well-written clients) */
419 GNUNET_NETWORK_fdset_copy (want, ready);
427 * Check if the given task is eligible to run now.
428 * Also set the reason why it is eligible.
430 * @param task task to check if it is ready
431 * @param now the current time
432 * @param rs set of FDs ready for reading
433 * @param ws set of FDs ready for writing
434 * @return GNUNET_YES if we can run it, GNUNET_NO if not.
437 is_ready (struct Task *task, struct GNUNET_TIME_Absolute now,
438 const struct GNUNET_NETWORK_FDSet *rs,
439 const struct GNUNET_NETWORK_FDSet *ws)
441 enum GNUNET_SCHEDULER_Reason reason;
443 reason = task->reason;
444 if (now.abs_value >= task->timeout.abs_value)
445 reason |= GNUNET_SCHEDULER_REASON_TIMEOUT;
446 if ((0 == (reason & GNUNET_SCHEDULER_REASON_READ_READY)) &&
447 (((task->read_fd != -1) &&
448 (GNUNET_YES == GNUNET_NETWORK_fdset_test_native (rs, task->read_fd))) ||
449 (set_overlaps (rs, task->read_set))))
450 reason |= GNUNET_SCHEDULER_REASON_READ_READY;
451 if ((0 == (reason & GNUNET_SCHEDULER_REASON_WRITE_READY)) &&
452 (((task->write_fd != -1) &&
453 (GNUNET_YES == GNUNET_NETWORK_fdset_test_native (ws, task->write_fd)))
454 || (set_overlaps (ws, task->write_set))))
455 reason |= GNUNET_SCHEDULER_REASON_WRITE_READY;
457 return GNUNET_NO; /* not ready */
458 if (task->prereq_id != GNUNET_SCHEDULER_NO_TASK)
460 if (GNUNET_YES == is_pending (task->prereq_id))
462 task->reason = reason;
463 return GNUNET_NO; /* prereq waiting */
465 reason |= GNUNET_SCHEDULER_REASON_PREREQ_DONE;
467 task->reason = reason;
473 * Put a task that is ready for execution into the ready queue.
475 * @param task task ready for execution
478 queue_ready_task (struct Task *task)
480 enum GNUNET_SCHEDULER_Priority p = task->priority;
482 if (0 != (task->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
483 p = GNUNET_SCHEDULER_PRIORITY_SHUTDOWN;
484 task->next = ready[check_priority (p)];
485 ready[check_priority (p)] = task;
491 * Check which tasks are ready and move them
492 * to the respective ready queue.
494 * @param rs FDs ready for reading
495 * @param ws FDs ready for writing
498 check_ready (const struct GNUNET_NETWORK_FDSet *rs,
499 const struct GNUNET_NETWORK_FDSet *ws)
504 struct GNUNET_TIME_Absolute now;
506 now = GNUNET_TIME_absolute_get ();
508 pos = pending_timeout;
512 if (now.abs_value >= pos->timeout.abs_value)
513 pos->reason |= GNUNET_SCHEDULER_REASON_TIMEOUT;
514 if (0 == pos->reason)
516 pending_timeout = next;
517 if (pending_timeout_last == pos)
518 pending_timeout_last = NULL;
519 queue_ready_task (pos);
526 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
527 "Checking readiness of task: %llu / %p\n", pos->id,
531 if (GNUNET_YES == is_ready (pos, now, rs, ws))
537 queue_ready_task (pos);
548 * Request the shutdown of a scheduler. Marks all currently
549 * pending tasks as ready because of shutdown. This will
550 * cause all tasks to run (as soon as possible, respecting
551 * priorities and prerequisite tasks). Note that tasks
552 * scheduled AFTER this call may still be delayed arbitrarily.
555 GNUNET_SCHEDULER_shutdown ()
560 pos = pending_timeout;
563 pos->reason |= GNUNET_SCHEDULER_REASON_SHUTDOWN;
564 /* we don't move the task into the ready queue yet; check_ready
565 * will do that later, possibly adding additional
566 * readiness-factors */
572 pos->reason |= GNUNET_SCHEDULER_REASON_SHUTDOWN;
573 /* we don't move the task into the ready queue yet; check_ready
574 * will do that later, possibly adding additional
575 * readiness-factors */
578 for (i = 0; i < GNUNET_SCHEDULER_PRIORITY_COUNT; i++)
583 pos->reason |= GNUNET_SCHEDULER_REASON_SHUTDOWN;
584 /* we don't move the task into the ready queue yet; check_ready
585 * will do that later, possibly adding additional
586 * readiness-factors */
594 * Destroy a task (release associated resources)
596 * @param t task to destroy
599 destroy_task (struct Task *t)
601 if (NULL != t->read_set)
602 GNUNET_NETWORK_fdset_destroy (t->read_set);
603 if (NULL != t->write_set)
604 GNUNET_NETWORK_fdset_destroy (t->write_set);
606 GNUNET_free (t->backtrace_strings);
613 * Run at least one task in the highest-priority queue that is not
614 * empty. Keep running tasks until we are either no longer running
615 * "URGENT" tasks or until we have at least one "pending" task (which
616 * may become ready, hence we should select on it). Naturally, if
617 * there are no more ready tasks, we also return.
619 * @param rs FDs ready for reading
620 * @param ws FDs ready for writing
623 run_ready (struct GNUNET_NETWORK_FDSet *rs, struct GNUNET_NETWORK_FDSet *ws)
625 enum GNUNET_SCHEDULER_Priority p;
627 struct GNUNET_SCHEDULER_TaskContext tc;
629 max_priority_added = GNUNET_SCHEDULER_PRIORITY_KEEP;
632 if (ready_count == 0)
634 GNUNET_assert (ready[GNUNET_SCHEDULER_PRIORITY_KEEP] == NULL);
635 /* yes, p>0 is correct, 0 is "KEEP" which should
636 * always be an empty queue (see assertion)! */
637 for (p = GNUNET_SCHEDULER_PRIORITY_COUNT - 1; p > 0; p--)
643 GNUNET_assert (pos != NULL); /* ready_count wrong? */
644 ready[p] = pos->next;
646 if (current_priority != pos->priority)
648 current_priority = pos->priority;
649 (void) GNUNET_OS_set_process_priority (GNUNET_OS_process_current (),
652 current_lifeness = pos->lifeness;
655 if (GNUNET_TIME_absolute_get_duration (pos->start_time).rel_value >
656 DELAY_THRESHOLD.rel_value)
658 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
659 "Task %llu took %llums to be scheduled\n", pos->id,
661 GNUNET_TIME_absolute_get_duration
662 (pos->start_time).rel_value);
665 tc.reason = pos->reason;
666 tc.read_ready = (pos->read_set == NULL) ? rs : pos->read_set;
667 if ((pos->read_fd != -1) &&
668 (0 != (pos->reason & GNUNET_SCHEDULER_REASON_READ_READY)))
669 GNUNET_NETWORK_fdset_set_native (rs, pos->read_fd);
670 tc.write_ready = (pos->write_set == NULL) ? ws : pos->write_set;
671 if ((pos->write_fd != -1) &&
672 (0 != (pos->reason & GNUNET_SCHEDULER_REASON_WRITE_READY)))
673 GNUNET_NETWORK_fdset_set_native (ws, pos->write_fd);
674 if (((tc.reason & GNUNET_SCHEDULER_REASON_WRITE_READY) != 0) &&
675 (pos->write_fd != -1) &&
676 (!GNUNET_NETWORK_fdset_test_native (ws, pos->write_fd)))
677 abort (); // added to ready in previous select loop!
679 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Running task: %llu / %p\n", pos->id,
682 pos->callback (pos->callback_cls, &tc);
686 for (i = 0; i < pos->num_backtrace_strings; i++)
687 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Task %llu trace %d: %s\n", pos->id,
688 i, pos->backtrace_strings[i]);
694 while ((pending == NULL) || (p >= max_priority_added));
698 * Pipe used to communicate shutdown via signal.
700 static struct GNUNET_DISK_PipeHandle *shutdown_pipe_handle;
703 * Signal handler called for SIGPIPE.
713 * Signal handler called for signals that should cause us to shutdown.
716 sighandler_shutdown ()
719 int old_errno = errno; /* backup errno */
721 GNUNET_DISK_file_write (GNUNET_DISK_pipe_handle
722 (shutdown_pipe_handle, GNUNET_DISK_PIPE_END_WRITE),
729 * Check if the system is still life. Trigger shutdown if we
730 * have tasks, but none of them give us lifeness.
732 * @return GNUNET_OK to continue the main loop,
742 for (t = pending; NULL != t; t = t->next)
743 if (t->lifeness == GNUNET_YES)
745 for (t = pending_timeout; NULL != t; t = t->next)
746 if (t->lifeness == GNUNET_YES)
748 if ((NULL != pending) || (NULL != pending_timeout))
750 GNUNET_SCHEDULER_shutdown ();
758 * Initialize and run scheduler. This function will return when all
759 * tasks have completed. On systems with signals, receiving a SIGTERM
760 * (and other similar signals) will cause "GNUNET_SCHEDULER_shutdown"
761 * to be run after the active task is complete. As a result, SIGTERM
762 * causes all active tasks to be scheduled with reason
763 * "GNUNET_SCHEDULER_REASON_SHUTDOWN". (However, tasks added
764 * afterwards will execute normally!). Note that any particular signal
765 * will only shut down one scheduler; applications should always only
766 * create a single scheduler.
768 * @param task task to run immediately
769 * @param task_cls closure of task
772 GNUNET_SCHEDULER_run (GNUNET_SCHEDULER_Task task, void *task_cls)
774 struct GNUNET_NETWORK_FDSet *rs;
775 struct GNUNET_NETWORK_FDSet *ws;
776 struct GNUNET_TIME_Relative timeout;
778 struct GNUNET_SIGNAL_Context *shc_int;
779 struct GNUNET_SIGNAL_Context *shc_term;
782 struct GNUNET_SIGNAL_Context *shc_quit;
783 struct GNUNET_SIGNAL_Context *shc_hup;
784 struct GNUNET_SIGNAL_Context *shc_pipe;
786 unsigned long long last_tr;
787 unsigned int busy_wait_warning;
788 const struct GNUNET_DISK_FileHandle *pr;
791 GNUNET_assert (active_task == NULL);
792 rs = GNUNET_NETWORK_fdset_create ();
793 ws = GNUNET_NETWORK_fdset_create ();
794 GNUNET_assert (shutdown_pipe_handle == NULL);
795 shutdown_pipe_handle = GNUNET_DISK_pipe (GNUNET_NO, GNUNET_NO, GNUNET_NO);
796 GNUNET_assert (shutdown_pipe_handle != NULL);
797 pr = GNUNET_DISK_pipe_handle (shutdown_pipe_handle,
798 GNUNET_DISK_PIPE_END_READ);
799 GNUNET_assert (pr != NULL);
800 shc_int = GNUNET_SIGNAL_handler_install (SIGINT, &sighandler_shutdown);
801 shc_term = GNUNET_SIGNAL_handler_install (SIGTERM, &sighandler_shutdown);
803 shc_pipe = GNUNET_SIGNAL_handler_install (SIGPIPE, &sighandler_pipe);
804 shc_quit = GNUNET_SIGNAL_handler_install (SIGQUIT, &sighandler_shutdown);
805 shc_hup = GNUNET_SIGNAL_handler_install (SIGHUP, &sighandler_shutdown);
807 current_priority = GNUNET_SCHEDULER_PRIORITY_DEFAULT;
808 current_lifeness = GNUNET_YES;
809 GNUNET_SCHEDULER_add_continuation (task, task_cls,
810 GNUNET_SCHEDULER_REASON_STARTUP);
811 #if ENABLE_WINDOWS_WORKAROUNDS
812 active_task = (void *) (long) -1; /* force passing of sanity check */
813 GNUNET_SCHEDULER_add_now_with_lifeness (GNUNET_NO,
814 &GNUNET_OS_install_parent_control_handler,
819 busy_wait_warning = 0;
820 while (GNUNET_OK == check_lifeness ())
822 GNUNET_NETWORK_fdset_zero (rs);
823 GNUNET_NETWORK_fdset_zero (ws);
824 timeout = GNUNET_TIME_UNIT_FOREVER_REL;
825 update_sets (rs, ws, &timeout);
826 GNUNET_NETWORK_fdset_handle_set (rs, pr);
829 /* no blocking, more work already ready! */
830 timeout = GNUNET_TIME_UNIT_ZERO;
832 if (NULL == scheduler_select)
833 ret = GNUNET_NETWORK_socket_select (rs, ws, NULL, timeout);
835 ret = scheduler_select (scheduler_select_cls, rs, ws, NULL, timeout);
836 if (ret == GNUNET_SYSERR)
841 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "select");
846 snprintf (lsof, sizeof (lsof), "lsof -p %d", getpid ());
849 if (0 != system (lsof))
850 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "system");
856 if ((ret == 0) && (timeout.rel_value == 0) && (busy_wait_warning > 16))
858 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
859 _("Looks like we're busy waiting...\n"));
860 sleep (1); /* mitigate */
862 check_ready (rs, ws);
864 if (GNUNET_NETWORK_fdset_handle_isset (rs, pr))
866 /* consume the signal */
867 GNUNET_DISK_file_read (pr, &c, sizeof (c));
868 /* mark all active tasks as ready due to shutdown */
869 GNUNET_SCHEDULER_shutdown ();
871 if (last_tr == tasks_run)
878 busy_wait_warning = 0;
881 GNUNET_SIGNAL_handler_uninstall (shc_int);
882 GNUNET_SIGNAL_handler_uninstall (shc_term);
884 GNUNET_SIGNAL_handler_uninstall (shc_pipe);
885 GNUNET_SIGNAL_handler_uninstall (shc_quit);
886 GNUNET_SIGNAL_handler_uninstall (shc_hup);
888 GNUNET_DISK_pipe_close (shutdown_pipe_handle);
889 shutdown_pipe_handle = NULL;
890 GNUNET_NETWORK_fdset_destroy (rs);
891 GNUNET_NETWORK_fdset_destroy (ws);
896 * Obtain the reason code for why the current task was
897 * started. Will return the same value as
898 * the GNUNET_SCHEDULER_TaskContext's reason field.
900 * @return reason(s) why the current task is run
902 enum GNUNET_SCHEDULER_Reason
903 GNUNET_SCHEDULER_get_reason ()
905 GNUNET_assert (active_task != NULL);
906 return active_task->reason;
911 * Get information about the current load of this scheduler. Use this
912 * function to determine if an elective task should be added or simply
913 * dropped (if the decision should be made based on the number of
914 * tasks ready to run).
916 * @param p priority level to look at
917 * @return number of tasks pending right now
920 GNUNET_SCHEDULER_get_load (enum GNUNET_SCHEDULER_Priority p)
925 GNUNET_assert (active_task != NULL);
926 if (p == GNUNET_SCHEDULER_PRIORITY_COUNT)
928 if (p == GNUNET_SCHEDULER_PRIORITY_KEEP)
929 p = current_priority;
931 pos = ready[check_priority (p)];
942 * Cancel the task with the specified identifier.
943 * The task must not yet have run.
945 * @param task id of the task to cancel
946 * @return original closure of the task
949 GNUNET_SCHEDULER_cancel (GNUNET_SCHEDULER_TaskIdentifier task)
953 enum GNUNET_SCHEDULER_Priority p;
957 GNUNET_assert (active_task != NULL);
980 if (pending_timeout_last == t)
981 pending_timeout_last = NULL;
987 if (p >= GNUNET_SCHEDULER_PRIORITY_COUNT)
989 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
990 _("Attempt to cancel dead task %llu!\n"),
991 (unsigned long long) task);
1017 pending_timeout = t->next;
1027 prev->next = t->next;
1029 ret = t->callback_cls;
1031 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Canceling task: %llu / %p\n", task,
1040 * Continue the current execution with the given function. This is
1041 * similar to the other "add" functions except that there is no delay
1042 * and the reason code can be specified.
1044 * @param task main function of the task
1045 * @param task_cls closure for 'main'
1046 * @param reason reason for task invocation
1049 GNUNET_SCHEDULER_add_continuation (GNUNET_SCHEDULER_Task task, void *task_cls,
1050 enum GNUNET_SCHEDULER_Reason reason)
1055 void *backtrace_array[50];
1058 GNUNET_assert (NULL != task);
1059 GNUNET_assert ((active_task != NULL) ||
1060 (reason == GNUNET_SCHEDULER_REASON_STARTUP));
1061 t = GNUNET_malloc (sizeof (struct Task));
1063 t->num_backtrace_strings = backtrace (backtrace_array, 50);
1064 t->backtrace_strings =
1065 backtrace_symbols (backtrace_array, t->num_backtrace_strings);
1070 t->callback_cls = task_cls;
1073 t->start_time = GNUNET_TIME_absolute_get ();
1076 t->priority = current_priority;
1077 t->lifeness = current_lifeness;
1079 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Adding continuation task: %llu / %p\n",
1080 t->id, t->callback_cls);
1082 queue_ready_task (t);
1088 * Schedule a new task to be run after the specified prerequisite task
1089 * has completed. It will be run with the priority of the calling
1092 * @param prerequisite_task run this task after the task with the given
1093 * task identifier completes (and any of our other
1094 * conditions, such as delay, read or write-readiness
1095 * are satisfied). Use GNUNET_SCHEDULER_NO_TASK to not have any dependency
1096 * on completion of other tasks (this will cause the task to run as
1097 * soon as possible).
1098 * @param task main function of the task
1099 * @param task_cls closure of task
1100 * @return unique task identifier for the job
1101 * only valid until "task" is started!
1103 GNUNET_SCHEDULER_TaskIdentifier
1104 GNUNET_SCHEDULER_add_after (GNUNET_SCHEDULER_TaskIdentifier prerequisite_task,
1105 GNUNET_SCHEDULER_Task task, void *task_cls)
1107 return GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_KEEP,
1108 prerequisite_task, GNUNET_TIME_UNIT_ZERO,
1109 NULL, NULL, task, task_cls);
1114 * Schedule a new task to be run with a specified priority.
1116 * @param prio how important is the new task?
1117 * @param task main function of the task
1118 * @param task_cls closure of task
1119 * @return unique task identifier for the job
1120 * only valid until "task" is started!
1122 GNUNET_SCHEDULER_TaskIdentifier
1123 GNUNET_SCHEDULER_add_with_priority (enum GNUNET_SCHEDULER_Priority prio,
1124 GNUNET_SCHEDULER_Task task, void *task_cls)
1126 return GNUNET_SCHEDULER_add_select (prio, GNUNET_SCHEDULER_NO_TASK,
1127 GNUNET_TIME_UNIT_ZERO, NULL, NULL, task,
1134 * Schedule a new task to be run with a specified delay. The task
1135 * will be scheduled for execution once the delay has expired. It
1136 * will be run with the priority of the calling task.
1138 * @param delay when should this operation time out? Use
1139 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1140 * @param task main function of the task
1141 * @param task_cls closure of task
1142 * @return unique task identifier for the job
1143 * only valid until "task" is started!
1145 GNUNET_SCHEDULER_TaskIdentifier
1146 GNUNET_SCHEDULER_add_delayed (struct GNUNET_TIME_Relative delay,
1147 GNUNET_SCHEDULER_Task task, void *task_cls)
1150 /* new, optimized version */
1156 void *backtrace_array[MAX_TRACE_DEPTH];
1159 GNUNET_assert (active_task != NULL);
1160 GNUNET_assert (NULL != task);
1161 t = GNUNET_malloc (sizeof (struct Task));
1163 t->callback_cls = task_cls;
1165 t->num_backtrace_strings = backtrace (backtrace_array, MAX_TRACE_DEPTH);
1166 t->backtrace_strings =
1167 backtrace_symbols (backtrace_array, t->num_backtrace_strings);
1173 t->start_time = GNUNET_TIME_absolute_get ();
1175 t->timeout = GNUNET_TIME_relative_to_absolute (delay);
1176 t->priority = current_priority;
1177 t->lifeness = current_lifeness;
1178 /* try tail first (optimization in case we are
1179 * appending to a long list of tasks with timeouts) */
1180 prev = pending_timeout_last;
1183 if (prev->timeout.abs_value > t->timeout.abs_value)
1186 pos = prev->next; /* heuristic success! */
1190 /* heuristic failed, do traversal of timeout list */
1191 pos = pending_timeout;
1193 while ((pos != NULL) &&
1194 ((pos->timeout.abs_value <= t->timeout.abs_value) ||
1195 (pos->reason != 0)))
1201 pending_timeout = t;
1205 /* hyper-optimization... */
1206 pending_timeout_last = t;
1209 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Adding task: %llu / %p\n", t->id,
1215 for (i = 0; i < t->num_backtrace_strings; i++)
1216 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Task %llu trace %d: %s\n", t->id, i,
1217 t->backtrace_strings[i]);
1222 /* unoptimized version */
1223 return GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_KEEP,
1224 GNUNET_SCHEDULER_NO_TASK, delay, NULL,
1225 NULL, task, task_cls);
1232 * Schedule a new task to be run as soon as possible. The task
1233 * will be run with the priority of the calling task.
1235 * @param task main function of the task
1236 * @param task_cls closure of task
1237 * @return unique task identifier for the job
1238 * only valid until "task" is started!
1240 GNUNET_SCHEDULER_TaskIdentifier
1241 GNUNET_SCHEDULER_add_now (GNUNET_SCHEDULER_Task task, void *task_cls)
1243 return GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_KEEP,
1244 GNUNET_SCHEDULER_NO_TASK,
1245 GNUNET_TIME_UNIT_ZERO, NULL, NULL, task,
1251 * Schedule a new task to be run as soon as possible with the
1252 * (transitive) ignore-shutdown flag either explicitly set or
1253 * explicitly enabled. This task (and all tasks created from it,
1254 * other than by another call to this function) will either count or
1255 * not count for the 'lifeness' of the process. This API is only
1256 * useful in a few special cases.
1258 * @param lifeness GNUNET_YES if the task counts for lifeness, GNUNET_NO if not.
1259 * @param task main function of the task
1260 * @param task_cls closure of task
1261 * @return unique task identifier for the job
1262 * only valid until "task" is started!
1264 GNUNET_SCHEDULER_TaskIdentifier
1265 GNUNET_SCHEDULER_add_now_with_lifeness (int lifeness,
1266 GNUNET_SCHEDULER_Task task,
1269 GNUNET_SCHEDULER_TaskIdentifier ret;
1272 GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_KEEP,
1273 GNUNET_SCHEDULER_NO_TASK,
1274 GNUNET_TIME_UNIT_ZERO, NULL, NULL, task,
1276 GNUNET_assert (pending->id == ret);
1277 pending->lifeness = lifeness;
1285 * Schedule a new task to be run with a specified delay or when any of
1286 * the specified file descriptor sets is ready. The delay can be used
1287 * as a timeout on the socket(s) being ready. The task will be
1288 * scheduled for execution once either the delay has expired or any of
1289 * the socket operations is ready. This is the most general
1290 * function of the "add" family. Note that the "prerequisite_task"
1291 * must be satisfied in addition to any of the other conditions. In
1292 * other words, the task will be started when
1294 * (prerequisite-run)
1298 * || shutdown-active )
1301 * @param delay how long should we wait? Use GNUNET_TIME_UNIT_FOREVER_REL for "forever",
1302 * which means that the task will only be run after we receive SIGTERM
1303 * @param rfd file descriptor we want to read (can be -1)
1304 * @param wfd file descriptors we want to write (can be -1)
1305 * @param task main function of the task
1306 * @param task_cls closure of task
1307 * @return unique task identifier for the job
1308 * only valid until "task" is started!
1311 GNUNET_SCHEDULER_TaskIdentifier
1312 add_without_sets (struct GNUNET_TIME_Relative delay, int rfd, int wfd,
1313 GNUNET_SCHEDULER_Task task, void *task_cls)
1318 void *backtrace_array[MAX_TRACE_DEPTH];
1321 GNUNET_assert (active_task != NULL);
1322 GNUNET_assert (NULL != task);
1323 t = GNUNET_malloc (sizeof (struct Task));
1325 t->callback_cls = task_cls;
1327 t->num_backtrace_strings = backtrace (backtrace_array, MAX_TRACE_DEPTH);
1328 t->backtrace_strings =
1329 backtrace_symbols (backtrace_array, t->num_backtrace_strings);
1334 int flags = fcntl (rfd, F_GETFD);
1336 if (flags == -1 && errno == EBADF)
1338 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Got invalid file descriptor %d!\n",
1343 for (i = 0; i < t->num_backtrace_strings; i++)
1344 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Trace: %s\n",
1345 t->backtrace_strings[i]);
1352 int flags = fcntl (wfd, F_GETFD);
1354 if (flags == -1 && errno == EBADF)
1356 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Got invalid file descriptor %d!\n",
1361 for (i = 0; i < t->num_backtrace_strings; i++)
1362 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Trace: %s\n",
1363 t->backtrace_strings[i]);
1370 GNUNET_assert (wfd >= -1);
1374 t->start_time = GNUNET_TIME_absolute_get ();
1376 t->prereq_id = GNUNET_SCHEDULER_NO_TASK;
1377 t->timeout = GNUNET_TIME_relative_to_absolute (delay);
1378 t->priority = check_priority (current_priority);
1379 t->lifeness = current_lifeness;
1382 max_priority_added = GNUNET_MAX (max_priority_added, t->priority);
1384 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Adding task: %llu / %p\n", t->id,
1390 for (i = 0; i < t->num_backtrace_strings; i++)
1391 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Task %llu trace %d: %s\n", t->id, i,
1392 t->backtrace_strings[i]);
1401 * Schedule a new task to be run with a specified delay or when the
1402 * specified file descriptor is ready for reading. The delay can be
1403 * used as a timeout on the socket being ready. The task will be
1404 * scheduled for execution once either the delay has expired or the
1405 * socket operation is ready. It will be run with the priority of
1408 * @param delay when should this operation time out? Use
1409 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1410 * @param rfd read file-descriptor
1411 * @param task main function of the task
1412 * @param task_cls closure of task
1413 * @return unique task identifier for the job
1414 * only valid until "task" is started!
1416 GNUNET_SCHEDULER_TaskIdentifier
1417 GNUNET_SCHEDULER_add_read_net (struct GNUNET_TIME_Relative delay,
1418 struct GNUNET_NETWORK_Handle *rfd,
1419 GNUNET_SCHEDULER_Task task, void *task_cls)
1422 struct GNUNET_NETWORK_FDSet *rs;
1423 GNUNET_SCHEDULER_TaskIdentifier ret;
1425 GNUNET_assert (rfd != NULL);
1426 rs = GNUNET_NETWORK_fdset_create ();
1427 GNUNET_NETWORK_fdset_set (rs, rfd);
1429 GNUNET_SCHEDULER_add_select (check_priority (current_priority),
1430 GNUNET_SCHEDULER_NO_TASK, delay, rs, NULL,
1432 GNUNET_NETWORK_fdset_destroy (rs);
1435 return add_without_sets (delay, GNUNET_NETWORK_get_fd (rfd), -1, task,
1442 * Schedule a new task to be run with a specified delay or when the
1443 * specified file descriptor is ready for writing. The delay can be
1444 * used as a timeout on the socket being ready. The task will be
1445 * scheduled for execution once either the delay has expired or the
1446 * socket operation is ready. It will be run with the priority of
1449 * @param delay when should this operation time out? Use
1450 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1451 * @param wfd write file-descriptor
1452 * @param task main function of the task
1453 * @param task_cls closure of task
1454 * @return unique task identifier for the job
1455 * only valid until "task" is started!
1457 GNUNET_SCHEDULER_TaskIdentifier
1458 GNUNET_SCHEDULER_add_write_net (struct GNUNET_TIME_Relative delay,
1459 struct GNUNET_NETWORK_Handle *wfd,
1460 GNUNET_SCHEDULER_Task task, void *task_cls)
1463 struct GNUNET_NETWORK_FDSet *ws;
1464 GNUNET_SCHEDULER_TaskIdentifier ret;
1466 GNUNET_assert (wfd != NULL);
1467 ws = GNUNET_NETWORK_fdset_create ();
1468 GNUNET_NETWORK_fdset_set (ws, wfd);
1470 GNUNET_SCHEDULER_add_select (check_priority (current_priority),
1471 GNUNET_SCHEDULER_NO_TASK, delay, NULL, ws,
1473 GNUNET_NETWORK_fdset_destroy (ws);
1476 GNUNET_assert (GNUNET_NETWORK_get_fd (wfd) >= 0);
1477 return add_without_sets (delay, -1, GNUNET_NETWORK_get_fd (wfd), task,
1484 * Schedule a new task to be run with a specified delay or when the
1485 * specified file descriptor is ready for reading. The delay can be
1486 * used as a timeout on the socket being ready. The task will be
1487 * scheduled for execution once either the delay has expired or the
1488 * socket operation is ready. It will be run with the priority of
1491 * @param delay when should this operation time out? Use
1492 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1493 * @param rfd read file-descriptor
1494 * @param task main function of the task
1495 * @param task_cls closure of task
1496 * @return unique task identifier for the job
1497 * only valid until "task" is started!
1499 GNUNET_SCHEDULER_TaskIdentifier
1500 GNUNET_SCHEDULER_add_read_file (struct GNUNET_TIME_Relative delay,
1501 const struct GNUNET_DISK_FileHandle *rfd,
1502 GNUNET_SCHEDULER_Task task, void *task_cls)
1505 struct GNUNET_NETWORK_FDSet *rs;
1506 GNUNET_SCHEDULER_TaskIdentifier ret;
1508 GNUNET_assert (rfd != NULL);
1509 rs = GNUNET_NETWORK_fdset_create ();
1510 GNUNET_NETWORK_fdset_handle_set (rs, rfd);
1512 GNUNET_SCHEDULER_add_select (check_priority (current_priority),
1513 GNUNET_SCHEDULER_NO_TASK, delay, rs, NULL,
1515 GNUNET_NETWORK_fdset_destroy (rs);
1520 GNUNET_DISK_internal_file_handle_ (rfd, &fd, sizeof (int));
1521 return add_without_sets (delay, fd, -1, task, task_cls);
1528 * Schedule a new task to be run with a specified delay or when the
1529 * specified file descriptor is ready for writing. The delay can be
1530 * used as a timeout on the socket being ready. The task will be
1531 * scheduled for execution once either the delay has expired or the
1532 * socket operation is ready. It will be run with the priority of
1535 * @param delay when should this operation time out? Use
1536 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
1537 * @param wfd write file-descriptor
1538 * @param task main function of the task
1539 * @param task_cls closure of task
1540 * @return unique task identifier for the job
1541 * only valid until "task" is started!
1543 GNUNET_SCHEDULER_TaskIdentifier
1544 GNUNET_SCHEDULER_add_write_file (struct GNUNET_TIME_Relative delay,
1545 const struct GNUNET_DISK_FileHandle *wfd,
1546 GNUNET_SCHEDULER_Task task, void *task_cls)
1549 struct GNUNET_NETWORK_FDSet *ws;
1550 GNUNET_SCHEDULER_TaskIdentifier ret;
1552 GNUNET_assert (wfd != NULL);
1553 ws = GNUNET_NETWORK_fdset_create ();
1554 GNUNET_NETWORK_fdset_handle_set (ws, wfd);
1556 GNUNET_SCHEDULER_add_select (check_priority (current_priority),
1557 GNUNET_SCHEDULER_NO_TASK, delay, NULL, ws,
1559 GNUNET_NETWORK_fdset_destroy (ws);
1564 GNUNET_DISK_internal_file_handle_ (wfd, &fd, sizeof (int));
1565 GNUNET_assert (fd >= 0);
1566 return add_without_sets (delay, -1, fd, task, task_cls);
1574 * Schedule a new task to be run with a specified delay or when any of
1575 * the specified file descriptor sets is ready. The delay can be used
1576 * as a timeout on the socket(s) being ready. The task will be
1577 * scheduled for execution once either the delay has expired or any of
1578 * the socket operations is ready. This is the most general
1579 * function of the "add" family. Note that the "prerequisite_task"
1580 * must be satisfied in addition to any of the other conditions. In
1581 * other words, the task will be started when
1583 * (prerequisite-run)
1587 * || (shutdown-active && run-on-shutdown) )
1590 * @param prio how important is this task?
1591 * @param prerequisite_task run this task after the task with the given
1592 * task identifier completes (and any of our other
1593 * conditions, such as delay, read or write-readiness
1594 * are satisfied). Use GNUNET_SCHEDULER_NO_TASK to not have any dependency
1595 * on completion of other tasks.
1596 * @param delay how long should we wait? Use GNUNET_TIME_UNIT_FOREVER_REL for "forever",
1597 * which means that the task will only be run after we receive SIGTERM
1598 * @param rs set of file descriptors we want to read (can be NULL)
1599 * @param ws set of file descriptors we want to write (can be NULL)
1600 * @param task main function of the task
1601 * @param task_cls closure of task
1602 * @return unique task identifier for the job
1603 * only valid until "task" is started!
1605 GNUNET_SCHEDULER_TaskIdentifier
1606 GNUNET_SCHEDULER_add_select (enum GNUNET_SCHEDULER_Priority prio,
1607 GNUNET_SCHEDULER_TaskIdentifier prerequisite_task,
1608 struct GNUNET_TIME_Relative delay,
1609 const struct GNUNET_NETWORK_FDSet *rs,
1610 const struct GNUNET_NETWORK_FDSet *ws,
1611 GNUNET_SCHEDULER_Task task, void *task_cls)
1616 void *backtrace_array[MAX_TRACE_DEPTH];
1619 GNUNET_assert (active_task != NULL);
1620 GNUNET_assert (NULL != task);
1621 t = GNUNET_malloc (sizeof (struct Task));
1623 t->callback_cls = task_cls;
1625 t->num_backtrace_strings = backtrace (backtrace_array, MAX_TRACE_DEPTH);
1626 t->backtrace_strings =
1627 backtrace_symbols (backtrace_array, t->num_backtrace_strings);
1633 t->read_set = GNUNET_NETWORK_fdset_create ();
1634 GNUNET_NETWORK_fdset_copy (t->read_set, rs);
1638 t->write_set = GNUNET_NETWORK_fdset_create ();
1639 GNUNET_NETWORK_fdset_copy (t->write_set, ws);
1643 t->start_time = GNUNET_TIME_absolute_get ();
1645 t->prereq_id = prerequisite_task;
1646 t->timeout = GNUNET_TIME_relative_to_absolute (delay);
1648 check_priority ((prio ==
1649 GNUNET_SCHEDULER_PRIORITY_KEEP) ? current_priority :
1651 t->lifeness = current_lifeness;
1654 max_priority_added = GNUNET_MAX (max_priority_added, t->priority);
1656 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Adding task: %llu / %p\n", t->id,
1662 for (i = 0; i < t->num_backtrace_strings; i++)
1663 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Task %llu trace %d: %s\n", t->id, i,
1664 t->backtrace_strings[i]);
1669 /* end of scheduler.c */