/*
This file is part of GNUnet
(C) 2009, 2011 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 2, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
/**
* @file util/scheduler.c
* @brief schedule computations using continuation passing style
* @author Christian Grothoff
*/
#include "platform.h"
#include "gnunet_common.h"
#include "gnunet_os_lib.h"
#include "gnunet_scheduler_lib.h"
#include "gnunet_signal_lib.h"
#include "gnunet_time_lib.h"
#include "disk.h"
#define LOG(kind,...) GNUNET_log_from (kind, "util-scheduler", __VA_ARGS__)
#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util-scheduler", syscall)
#if HAVE_EXECINFO_H
#include "execinfo.h"
/**
* Use lsof to generate file descriptor reports on select error?
* (turn off for stable releases).
*/
#define USE_LSOF GNUNET_NO
/**
* Obtain trace information for all scheduler calls that schedule tasks.
*/
#define EXECINFO GNUNET_NO
/**
* Check each file descriptor before adding
*/
#define DEBUG_FDS GNUNET_NO
/**
* Depth of the traces collected via EXECINFO.
*/
#define MAX_TRACE_DEPTH 50
#endif
/**
* Should we figure out which tasks are delayed for a while
* before they are run? (Consider using in combination with EXECINFO).
*/
#define PROFILE_DELAYS GNUNET_NO
/**
* Task that were in the queue for longer than this are reported if
* PROFILE_DELAYS is active.
*/
#define DELAY_THRESHOLD GNUNET_TIME_UNIT_SECONDS
/**
* Linked list of pending tasks.
*/
struct Task
{
/**
* This is a linked list.
*/
struct Task *next;
/**
* Function to run when ready.
*/
GNUNET_SCHEDULER_Task callback;
/**
* Closure for the callback.
*/
void *callback_cls;
/**
* Set of file descriptors this task is waiting
* for for reading. Once ready, this is updated
* to reflect the set of file descriptors ready
* for operation.
*/
struct GNUNET_NETWORK_FDSet *read_set;
/**
* Set of file descriptors this task is waiting for for writing.
* Once ready, this is updated to reflect the set of file
* descriptors ready for operation.
*/
struct GNUNET_NETWORK_FDSet *write_set;
/**
* Unique task identifier.
*/
GNUNET_SCHEDULER_TaskIdentifier id;
/**
* Absolute timeout value for the task, or
* GNUNET_TIME_UNIT_FOREVER_ABS for "no timeout".
*/
struct GNUNET_TIME_Absolute timeout;
#if PROFILE_DELAYS
/**
* When was the task scheduled?
*/
struct GNUNET_TIME_Absolute start_time;
#endif
/**
* Why is the task ready? Set after task is added to ready queue.
* Initially set to zero. All reasons that have already been
* satisfied (i.e. read or write ready) will be set over time.
*/
enum GNUNET_SCHEDULER_Reason reason;
/**
* Task priority.
*/
enum GNUNET_SCHEDULER_Priority priority;
/**
* Set if we only wait for reading from a single FD, otherwise -1.
*/
int read_fd;
/**
* Set if we only wait for writing to a single FD, otherwise -1.
*/
int write_fd;
/**
* Should the existence of this task in the queue be counted as
* reason to not shutdown the scheduler?
*/
int lifeness;
#if EXECINFO
/**
* Array of strings which make up a backtrace from the point when this
* task was scheduled (essentially, who scheduled the task?)
*/
char **backtrace_strings;
/**
* Size of the backtrace_strings array
*/
int num_backtrace_strings;
#endif
};
/**
* List of tasks waiting for an event.
*/
static struct Task *pending;
/**
* List of tasks waiting ONLY for a timeout event.
* Sorted by timeout (earliest first). Used so that
* we do not traverse the list of these tasks when
* building select sets (we just look at the head
* to determine the respective timeout ONCE).
*/
static struct Task *pending_timeout;
/**
* Last inserted task waiting ONLY for a timeout event.
* Used to (heuristically) speed up insertion.
*/
static struct Task *pending_timeout_last;
/**
* ID of the task that is running right now.
*/
static struct Task *active_task;
/**
* List of tasks ready to run right now,
* grouped by importance.
*/
static struct Task *ready[GNUNET_SCHEDULER_PRIORITY_COUNT];
/**
* Identity of the last task queued. Incremented for each task to
* generate a unique task ID (it is virtually impossible to start
* more than 2^64 tasks during the lifetime of a process).
*/
static GNUNET_SCHEDULER_TaskIdentifier last_id;
/**
* Number of tasks on the ready list.
*/
static unsigned int ready_count;
/**
* How many tasks have we run so far?
*/
static unsigned long long tasks_run;
/**
* Priority of the task running right now. Only
* valid while a task is running.
*/
static enum GNUNET_SCHEDULER_Priority current_priority;
/**
* Priority of the highest task added in the current select
* iteration.
*/
static enum GNUNET_SCHEDULER_Priority max_priority_added;
/**
* Value of the 'lifeness' flag for the current task.
*/
static int current_lifeness;
/**
* Function to use as a select() in the scheduler.
* If NULL, we use GNUNET_NETWORK_socket_select ().
*/
static GNUNET_SCHEDULER_select scheduler_select;
/**
* Closure for 'scheduler_select'.
*/
static void *scheduler_select_cls;
/**
* Sets the select function to use in the scheduler (scheduler_select).
*
* @param new_select new select function to use
* @param new_select_cls closure for 'new_select'
* @return previously used select function, NULL for default
*/
void
GNUNET_SCHEDULER_set_select (GNUNET_SCHEDULER_select new_select,
void *new_select_cls)
{
scheduler_select = new_select;
scheduler_select_cls = new_select_cls;
}
/**
* Check that the given priority is legal (and return it).
*
* @param p priority value to check
* @return p on success, 0 on error
*/
static enum GNUNET_SCHEDULER_Priority
check_priority (enum GNUNET_SCHEDULER_Priority p)
{
if ((p >= 0) && (p < GNUNET_SCHEDULER_PRIORITY_COUNT))
return p;
GNUNET_assert (0);
return 0; /* make compiler happy */
}
/**
* Update all sets and timeout for select.
*
* @param rs read-set, set to all FDs we would like to read (updated)
* @param ws write-set, set to all FDs we would like to write (updated)
* @param timeout next timeout (updated)
*/
static void
update_sets (struct GNUNET_NETWORK_FDSet *rs, struct GNUNET_NETWORK_FDSet *ws,
struct GNUNET_TIME_Relative *timeout)
{
struct Task *pos;
struct GNUNET_TIME_Absolute now;
struct GNUNET_TIME_Relative to;
now = GNUNET_TIME_absolute_get ();
pos = pending_timeout;
if (pos != NULL)
{
to = GNUNET_TIME_absolute_get_difference (now, pos->timeout);
if (timeout->rel_value > to.rel_value)
*timeout = to;
if (pos->reason != 0)
*timeout = GNUNET_TIME_UNIT_ZERO;
}
pos = pending;
while (pos != NULL)
{
if (pos->timeout.abs_value != GNUNET_TIME_UNIT_FOREVER_ABS.abs_value)
{
to = GNUNET_TIME_absolute_get_difference (now, pos->timeout);
if (timeout->rel_value > to.rel_value)
*timeout = to;
}
if (pos->read_fd != -1)
GNUNET_NETWORK_fdset_set_native (rs, pos->read_fd);
if (pos->write_fd != -1)
GNUNET_NETWORK_fdset_set_native (ws, pos->write_fd);
if (pos->read_set != NULL)
GNUNET_NETWORK_fdset_add (rs, pos->read_set);
if (pos->write_set != NULL)
GNUNET_NETWORK_fdset_add (ws, pos->write_set);
if (pos->reason != 0)
*timeout = GNUNET_TIME_UNIT_ZERO;
pos = pos->next;
}
}
/**
* Check if the ready set overlaps with the set we want to have ready.
* If so, update the want set (set all FDs that are ready). If not,
* return GNUNET_NO.
*
* @param ready set that is ready
* @param want set that we want to be ready
* @return GNUNET_YES if there was some overlap
*/
static int
set_overlaps (const struct GNUNET_NETWORK_FDSet *ready,
struct GNUNET_NETWORK_FDSet *want)
{
if ((NULL == want) || (NULL == ready))
return GNUNET_NO;
if (GNUNET_NETWORK_fdset_overlap (ready, want))
{
/* copy all over (yes, there maybe unrelated bits,
* but this should not hurt well-written clients) */
GNUNET_NETWORK_fdset_copy (want, ready);
return GNUNET_YES;
}
return GNUNET_NO;
}
/**
* Check if the given task is eligible to run now.
* Also set the reason why it is eligible.
*
* @param task task to check if it is ready
* @param now the current time
* @param rs set of FDs ready for reading
* @param ws set of FDs ready for writing
* @return GNUNET_YES if we can run it, GNUNET_NO if not.
*/
static int
is_ready (struct Task *task, struct GNUNET_TIME_Absolute now,
const struct GNUNET_NETWORK_FDSet *rs,
const struct GNUNET_NETWORK_FDSet *ws)
{
enum GNUNET_SCHEDULER_Reason reason;
reason = task->reason;
if (now.abs_value >= task->timeout.abs_value)
reason |= GNUNET_SCHEDULER_REASON_TIMEOUT;
if ((0 == (reason & GNUNET_SCHEDULER_REASON_READ_READY)) &&
(((task->read_fd != -1) &&
(GNUNET_YES == GNUNET_NETWORK_fdset_test_native (rs, task->read_fd))) ||
(set_overlaps (rs, task->read_set))))
reason |= GNUNET_SCHEDULER_REASON_READ_READY;
if ((0 == (reason & GNUNET_SCHEDULER_REASON_WRITE_READY)) &&
(((task->write_fd != -1) &&
(GNUNET_YES == GNUNET_NETWORK_fdset_test_native (ws, task->write_fd)))
|| (set_overlaps (ws, task->write_set))))
reason |= GNUNET_SCHEDULER_REASON_WRITE_READY;
if (reason == 0)
return GNUNET_NO; /* not ready */
reason |= GNUNET_SCHEDULER_REASON_PREREQ_DONE;
task->reason = reason;
return GNUNET_YES;
}
/**
* Put a task that is ready for execution into the ready queue.
*
* @param task task ready for execution
*/
static void
queue_ready_task (struct Task *task)
{
enum GNUNET_SCHEDULER_Priority p = task->priority;
if (0 != (task->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
p = GNUNET_SCHEDULER_PRIORITY_SHUTDOWN;
task->next = ready[check_priority (p)];
ready[check_priority (p)] = task;
ready_count++;
}
/**
* Check which tasks are ready and move them
* to the respective ready queue.
*
* @param rs FDs ready for reading
* @param ws FDs ready for writing
*/
static void
check_ready (const struct GNUNET_NETWORK_FDSet *rs,
const struct GNUNET_NETWORK_FDSet *ws)
{
struct Task *pos;
struct Task *prev;
struct Task *next;
struct GNUNET_TIME_Absolute now;
now = GNUNET_TIME_absolute_get ();
prev = NULL;
pos = pending_timeout;
while (pos != NULL)
{
next = pos->next;
if (now.abs_value >= pos->timeout.abs_value)
pos->reason |= GNUNET_SCHEDULER_REASON_TIMEOUT;
if (0 == pos->reason)
break;
pending_timeout = next;
if (pending_timeout_last == pos)
pending_timeout_last = NULL;
queue_ready_task (pos);
pos = next;
}
pos = pending;
while (pos != NULL)
{
LOG (GNUNET_ERROR_TYPE_DEBUG,
"Checking readiness of task: %llu / %p\n",
pos->id, pos->callback_cls);
next = pos->next;
if (GNUNET_YES == is_ready (pos, now, rs, ws))
{
if (prev == NULL)
pending = next;
else
prev->next = next;
queue_ready_task (pos);
pos = next;
continue;
}
prev = pos;
pos = next;
}
}
/**
* Request the shutdown of a scheduler. Marks all currently
* pending tasks as ready because of shutdown. This will
* cause all tasks to run (as soon as possible, respecting
* priorities and prerequisite tasks). Note that tasks
* scheduled AFTER this call may still be delayed arbitrarily.
*/
void
GNUNET_SCHEDULER_shutdown ()
{
struct Task *pos;
int i;
pos = pending_timeout;
while (pos != NULL)
{
pos->reason |= GNUNET_SCHEDULER_REASON_SHUTDOWN;
/* we don't move the task into the ready queue yet; check_ready
* will do that later, possibly adding additional
* readiness-factors */
pos = pos->next;
}
pos = pending;
while (pos != NULL)
{
pos->reason |= GNUNET_SCHEDULER_REASON_SHUTDOWN;
/* we don't move the task into the ready queue yet; check_ready
* will do that later, possibly adding additional
* readiness-factors */
pos = pos->next;
}
for (i = 0; i < GNUNET_SCHEDULER_PRIORITY_COUNT; i++)
{
pos = ready[i];
while (pos != NULL)
{
pos->reason |= GNUNET_SCHEDULER_REASON_SHUTDOWN;
/* we don't move the task into the ready queue yet; check_ready
* will do that later, possibly adding additional
* readiness-factors */
pos = pos->next;
}
}
}
/**
* Destroy a task (release associated resources)
*
* @param t task to destroy
*/
static void
destroy_task (struct Task *t)
{
if (NULL != t->read_set)
GNUNET_NETWORK_fdset_destroy (t->read_set);
if (NULL != t->write_set)
GNUNET_NETWORK_fdset_destroy (t->write_set);
#if EXECINFO
GNUNET_free (t->backtrace_strings);
#endif
GNUNET_free (t);
}
/**
* Run at least one task in the highest-priority queue that is not
* empty. Keep running tasks until we are either no longer running
* "URGENT" tasks or until we have at least one "pending" task (which
* may become ready, hence we should select on it). Naturally, if
* there are no more ready tasks, we also return.
*
* @param rs FDs ready for reading
* @param ws FDs ready for writing
*/
static void
run_ready (struct GNUNET_NETWORK_FDSet *rs, struct GNUNET_NETWORK_FDSet *ws)
{
enum GNUNET_SCHEDULER_Priority p;
struct Task *pos;
struct GNUNET_SCHEDULER_TaskContext tc;
max_priority_added = GNUNET_SCHEDULER_PRIORITY_KEEP;
do
{
if (ready_count == 0)
return;
GNUNET_assert (ready[GNUNET_SCHEDULER_PRIORITY_KEEP] == NULL);
/* yes, p>0 is correct, 0 is "KEEP" which should
* always be an empty queue (see assertion)! */
for (p = GNUNET_SCHEDULER_PRIORITY_COUNT - 1; p > 0; p--)
{
pos = ready[p];
if (pos != NULL)
break;
}
GNUNET_assert (pos != NULL); /* ready_count wrong? */
ready[p] = pos->next;
ready_count--;
current_priority = pos->priority;
current_lifeness = pos->lifeness;
active_task = pos;
#if PROFILE_DELAYS
if (GNUNET_TIME_absolute_get_duration (pos->start_time).rel_value >
DELAY_THRESHOLD.rel_value)
{
LOG (GNUNET_ERROR_TYPE_DEBUG,
"Task %llu took %s to be scheduled\n",
(unsigned long long) pos->id,
GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_duration (pos->start_time), GNUNET_YES));
}
#endif
tc.reason = pos->reason;
tc.read_ready = (pos->read_set == NULL) ? rs : pos->read_set;
if ((pos->read_fd != -1) &&
(0 != (pos->reason & GNUNET_SCHEDULER_REASON_READ_READY)))
GNUNET_NETWORK_fdset_set_native (rs, pos->read_fd);
tc.write_ready = (pos->write_set == NULL) ? ws : pos->write_set;
if ((pos->write_fd != -1) &&
(0 != (pos->reason & GNUNET_SCHEDULER_REASON_WRITE_READY)))
GNUNET_NETWORK_fdset_set_native (ws, pos->write_fd);
if (((tc.reason & GNUNET_SCHEDULER_REASON_WRITE_READY) != 0) &&
(pos->write_fd != -1) &&
(!GNUNET_NETWORK_fdset_test_native (ws, pos->write_fd)))
GNUNET_abort (); // added to ready in previous select loop!
LOG (GNUNET_ERROR_TYPE_DEBUG,
"Running task: %llu / %p\n", pos->id,
pos->callback_cls);
pos->callback (pos->callback_cls, &tc);
#if EXECINFO
int i;
for (i = 0; i < pos->num_backtrace_strings; i++)
LOG (GNUNET_ERROR_TYPE_ERROR, "Task %llu trace %d: %s\n", pos->id, i,
pos->backtrace_strings[i]);
#endif
active_task = NULL;
destroy_task (pos);
tasks_run++;
}
while ((pending == NULL) || (p >= max_priority_added));
}
/**
* Pipe used to communicate shutdown via signal.
*/
static struct GNUNET_DISK_PipeHandle *shutdown_pipe_handle;
/**
* Process ID of this process at the time we installed the various
* signal handlers.
*/
static pid_t my_pid;
/**
* Signal handler called for SIGPIPE.
*/
#ifndef MINGW
static void
sighandler_pipe ()
{
return;
}
#endif
/**
* Signal handler called for signals that should cause us to shutdown.
*/
static void
sighandler_shutdown ()
{
static char c;
int old_errno = errno; /* backup errno */
if (getpid () != my_pid)
exit (1); /* we have fork'ed since the signal handler was created,
* ignore the signal, see https://gnunet.org/vfork discussion */
GNUNET_DISK_file_write (GNUNET_DISK_pipe_handle
(shutdown_pipe_handle, GNUNET_DISK_PIPE_END_WRITE),
&c, sizeof (c));
errno = old_errno;
}
/**
* Check if the system is still life. Trigger shutdown if we
* have tasks, but none of them give us lifeness.
*
* @return GNUNET_OK to continue the main loop,
* GNUNET_NO to exit
*/
static int
check_lifeness ()
{
struct Task *t;
if (ready_count > 0)
return GNUNET_OK;
for (t = pending; NULL != t; t = t->next)
if (t->lifeness == GNUNET_YES)
return GNUNET_OK;
for (t = pending_timeout; NULL != t; t = t->next)
if (t->lifeness == GNUNET_YES)
return GNUNET_OK;
if ((NULL != pending) || (NULL != pending_timeout))
{
GNUNET_SCHEDULER_shutdown ();
return GNUNET_OK;
}
return GNUNET_NO;
}
/**
* Initialize and run scheduler. This function will return when all
* tasks have completed. On systems with signals, receiving a SIGTERM
* (and other similar signals) will cause "GNUNET_SCHEDULER_shutdown"
* to be run after the active task is complete. As a result, SIGTERM
* causes all active tasks to be scheduled with reason
* "GNUNET_SCHEDULER_REASON_SHUTDOWN". (However, tasks added
* afterwards will execute normally!). Note that any particular signal
* will only shut down one scheduler; applications should always only
* create a single scheduler.
*
* @param task task to run immediately
* @param task_cls closure of task
*/
void
GNUNET_SCHEDULER_run (GNUNET_SCHEDULER_Task task, void *task_cls)
{
struct GNUNET_NETWORK_FDSet *rs;
struct GNUNET_NETWORK_FDSet *ws;
struct GNUNET_TIME_Relative timeout;
int ret;
struct GNUNET_SIGNAL_Context *shc_int;
struct GNUNET_SIGNAL_Context *shc_term;
#ifndef MINGW
struct GNUNET_SIGNAL_Context *shc_quit;
struct GNUNET_SIGNAL_Context *shc_hup;
struct GNUNET_SIGNAL_Context *shc_pipe;
#endif
unsigned long long last_tr;
unsigned int busy_wait_warning;
const struct GNUNET_DISK_FileHandle *pr;
char c;
GNUNET_assert (active_task == NULL);
rs = GNUNET_NETWORK_fdset_create ();
ws = GNUNET_NETWORK_fdset_create ();
GNUNET_assert (shutdown_pipe_handle == NULL);
shutdown_pipe_handle = GNUNET_DISK_pipe (GNUNET_NO, GNUNET_NO, GNUNET_NO, GNUNET_NO);
GNUNET_assert (shutdown_pipe_handle != NULL);
pr = GNUNET_DISK_pipe_handle (shutdown_pipe_handle,
GNUNET_DISK_PIPE_END_READ);
GNUNET_assert (pr != NULL);
my_pid = getpid ();
LOG (GNUNET_ERROR_TYPE_DEBUG, "Registering signal handlers\n");
shc_int = GNUNET_SIGNAL_handler_install (SIGINT, &sighandler_shutdown);
shc_term = GNUNET_SIGNAL_handler_install (SIGTERM, &sighandler_shutdown);
#ifndef MINGW
shc_pipe = GNUNET_SIGNAL_handler_install (SIGPIPE, &sighandler_pipe);
shc_quit = GNUNET_SIGNAL_handler_install (SIGQUIT, &sighandler_shutdown);
shc_hup = GNUNET_SIGNAL_handler_install (SIGHUP, &sighandler_shutdown);
#endif
current_priority = GNUNET_SCHEDULER_PRIORITY_DEFAULT;
current_lifeness = GNUNET_YES;
GNUNET_SCHEDULER_add_continuation (task, task_cls,
GNUNET_SCHEDULER_REASON_STARTUP);
active_task = (void *) (long) -1; /* force passing of sanity check */
GNUNET_SCHEDULER_add_now_with_lifeness (GNUNET_NO,
&GNUNET_OS_install_parent_control_handler,
NULL);
active_task = NULL;
last_tr = 0;
busy_wait_warning = 0;
while (GNUNET_OK == check_lifeness ())
{
GNUNET_NETWORK_fdset_zero (rs);
GNUNET_NETWORK_fdset_zero (ws);
timeout = GNUNET_TIME_UNIT_FOREVER_REL;
update_sets (rs, ws, &timeout);
GNUNET_NETWORK_fdset_handle_set (rs, pr);
if (ready_count > 0)
{
/* no blocking, more work already ready! */
timeout = GNUNET_TIME_UNIT_ZERO;
}
if (NULL == scheduler_select)
ret = GNUNET_NETWORK_socket_select (rs, ws, NULL, timeout);
else
ret = scheduler_select (scheduler_select_cls, rs, ws, NULL, timeout);
if (ret == GNUNET_SYSERR)
{
if (errno == EINTR)
continue;
LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "select");
#ifndef MINGW
#if USE_LSOF
char lsof[512];
snprintf (lsof, sizeof (lsof), "lsof -p %d", getpid ());
(void) close (1);
(void) dup2 (2, 1);
if (0 != system (lsof))
LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "system");
#endif
#endif
GNUNET_abort ();
break;
}
if ((ret == 0) && (timeout.rel_value == 0) && (busy_wait_warning > 16))
{
LOG (GNUNET_ERROR_TYPE_WARNING, _("Looks like we're busy waiting...\n"));
sleep (1); /* mitigate */
}
check_ready (rs, ws);
run_ready (rs, ws);
if (GNUNET_NETWORK_fdset_handle_isset (rs, pr))
{
/* consume the signal */
GNUNET_DISK_file_read (pr, &c, sizeof (c));
/* mark all active tasks as ready due to shutdown */
GNUNET_SCHEDULER_shutdown ();
}
if (last_tr == tasks_run)
{
busy_wait_warning++;
}
else
{
last_tr = tasks_run;
busy_wait_warning = 0;
}
}
GNUNET_SIGNAL_handler_uninstall (shc_int);
GNUNET_SIGNAL_handler_uninstall (shc_term);
#ifndef MINGW
GNUNET_SIGNAL_handler_uninstall (shc_pipe);
GNUNET_SIGNAL_handler_uninstall (shc_quit);
GNUNET_SIGNAL_handler_uninstall (shc_hup);
#endif
GNUNET_DISK_pipe_close (shutdown_pipe_handle);
shutdown_pipe_handle = NULL;
GNUNET_NETWORK_fdset_destroy (rs);
GNUNET_NETWORK_fdset_destroy (ws);
}
/**
* Obtain the reason code for why the current task was
* started. Will return the same value as
* the GNUNET_SCHEDULER_TaskContext's reason field.
*
* @return reason(s) why the current task is run
*/
enum GNUNET_SCHEDULER_Reason
GNUNET_SCHEDULER_get_reason ()
{
GNUNET_assert (active_task != NULL);
return active_task->reason;
}
/**
* Get information about the current load of this scheduler. Use this
* function to determine if an elective task should be added or simply
* dropped (if the decision should be made based on the number of
* tasks ready to run).
*
* @param p priority level to look at
* @return number of tasks pending right now
*/
unsigned int
GNUNET_SCHEDULER_get_load (enum GNUNET_SCHEDULER_Priority p)
{
struct Task *pos;
unsigned int ret;
GNUNET_assert (active_task != NULL);
if (p == GNUNET_SCHEDULER_PRIORITY_COUNT)
return ready_count;
if (p == GNUNET_SCHEDULER_PRIORITY_KEEP)
p = current_priority;
ret = 0;
pos = ready[check_priority (p)];
while (pos != NULL)
{
pos = pos->next;
ret++;
}
return ret;
}
/**
* Cancel the task with the specified identifier.
* The task must not yet have run.
*
* @param task id of the task to cancel
* @return original closure of the task
*/
void *
GNUNET_SCHEDULER_cancel (GNUNET_SCHEDULER_TaskIdentifier task)
{
struct Task *t;
struct Task *prev;
enum GNUNET_SCHEDULER_Priority p;
int to;
void *ret;
GNUNET_assert (active_task != NULL);
to = 0;
prev = NULL;
t = pending;
while (t != NULL)
{
if (t->id == task)
break;
prev = t;
t = t->next;
}
if (t == NULL)
{
prev = NULL;
to = 1;
t = pending_timeout;
while (t != NULL)
{
if (t->id == task)
break;
prev = t;
t = t->next;
}
if (pending_timeout_last == t)
pending_timeout_last = NULL;
}
p = 0;
while (t == NULL)
{
p++;
if (p >= GNUNET_SCHEDULER_PRIORITY_COUNT)
{
LOG (GNUNET_ERROR_TYPE_ERROR, _("Attempt to cancel dead task %llu!\n"),
(unsigned long long) task);
GNUNET_assert (0);
}
prev = NULL;
t = ready[p];
while (t != NULL)
{
if (t->id == task)
{
ready_count--;
break;
}
prev = t;
t = t->next;
}
}
if (prev == NULL)
{
if (p == 0)
{
if (to == 0)
{
pending = t->next;
}
else
{
pending_timeout = t->next;
}
}
else
{
ready[p] = t->next;
}
}
else
{
prev->next = t->next;
}
ret = t->callback_cls;
LOG (GNUNET_ERROR_TYPE_DEBUG, "Canceling task: %llu / %p\n", task,
t->callback_cls);
destroy_task (t);
return ret;
}
/**
* Continue the current execution with the given function. This is
* similar to the other "add" functions except that there is no delay
* and the reason code can be specified.
*
* @param task main function of the task
* @param task_cls closure for 'main'
* @param reason reason for task invocation
* @param priority priority to use for the task
*/
void
GNUNET_SCHEDULER_add_continuation_with_priority (GNUNET_SCHEDULER_Task task, void *task_cls,
enum GNUNET_SCHEDULER_Reason reason,
enum GNUNET_SCHEDULER_Priority priority)
{
struct Task *t;
#if EXECINFO
void *backtrace_array[50];
#endif
GNUNET_assert (NULL != task);
GNUNET_assert ((active_task != NULL) ||
(reason == GNUNET_SCHEDULER_REASON_STARTUP));
t = GNUNET_malloc (sizeof (struct Task));
#if EXECINFO
t->num_backtrace_strings = backtrace (backtrace_array, 50);
t->backtrace_strings =
backtrace_symbols (backtrace_array, t->num_backtrace_strings);
#endif
t->read_fd = -1;
t->write_fd = -1;
t->callback = task;
t->callback_cls = task_cls;
t->id = ++last_id;
#if PROFILE_DELAYS
t->start_time = GNUNET_TIME_absolute_get ();
#endif
t->reason = reason;
t->priority = priority;
t->lifeness = current_lifeness;
LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding continuation task: %llu / %p\n", t->id,
t->callback_cls);
queue_ready_task (t);
}
/**
* Continue the current execution with the given function. This is
* similar to the other "add" functions except that there is no delay
* and the reason code can be specified.
*
* @param task main function of the task
* @param task_cls closure for 'main'
* @param reason reason for task invocation
*/
void
GNUNET_SCHEDULER_add_continuation (GNUNET_SCHEDULER_Task task, void *task_cls,
enum GNUNET_SCHEDULER_Reason reason)
{
GNUNET_SCHEDULER_add_continuation_with_priority (task, task_cls,
reason,
GNUNET_SCHEDULER_PRIORITY_DEFAULT);
}
/**
* Schedule a new task to be run with a specified priority.
*
* @param prio how important is the new task?
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_with_priority (enum GNUNET_SCHEDULER_Priority prio,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
return GNUNET_SCHEDULER_add_select (prio,
GNUNET_TIME_UNIT_ZERO, NULL, NULL, task,
task_cls);
}
/**
* Schedule a new task to be run with a specified delay. The task
* will be scheduled for execution once the delay has expired.
*
* @param delay when should this operation time out? Use
* GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
* @param priority priority to use for the task
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_delayed_with_priority (struct GNUNET_TIME_Relative delay,
enum GNUNET_SCHEDULER_Priority priority,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
struct Task *t;
struct Task *pos;
struct Task *prev;
#if EXECINFO
void *backtrace_array[MAX_TRACE_DEPTH];
#endif
GNUNET_assert (active_task != NULL);
GNUNET_assert (NULL != task);
t = GNUNET_malloc (sizeof (struct Task));
t->callback = task;
t->callback_cls = task_cls;
#if EXECINFO
t->num_backtrace_strings = backtrace (backtrace_array, MAX_TRACE_DEPTH);
t->backtrace_strings =
backtrace_symbols (backtrace_array, t->num_backtrace_strings);
#endif
t->read_fd = -1;
t->write_fd = -1;
t->id = ++last_id;
#if PROFILE_DELAYS
t->start_time = GNUNET_TIME_absolute_get ();
#endif
t->timeout = GNUNET_TIME_relative_to_absolute (delay);
t->priority = priority;
t->lifeness = current_lifeness;
/* try tail first (optimization in case we are
* appending to a long list of tasks with timeouts) */
prev = pending_timeout_last;
if (prev != NULL)
{
if (prev->timeout.abs_value > t->timeout.abs_value)
prev = NULL;
else
pos = prev->next; /* heuristic success! */
}
if (prev == NULL)
{
/* heuristic failed, do traversal of timeout list */
pos = pending_timeout;
}
while ((pos != NULL) &&
((pos->timeout.abs_value <= t->timeout.abs_value) ||
(pos->reason != 0)))
{
prev = pos;
pos = pos->next;
}
if (prev == NULL)
pending_timeout = t;
else
prev->next = t;
t->next = pos;
/* hyper-optimization... */
pending_timeout_last = t;
LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding task: %llu / %p\n", t->id,
t->callback_cls);
#if EXECINFO
int i;
for (i = 0; i < t->num_backtrace_strings; i++)
LOG (GNUNET_ERROR_TYPE_DEBUG, "Task %llu trace %d: %s\n", t->id, i,
t->backtrace_strings[i]);
#endif
return t->id;
}
/**
* Schedule a new task to be run with a specified delay. The task
* will be scheduled for execution once the delay has expired. It
* will be run with the DEFAULT priority.
*
* @param delay when should this operation time out? Use
* GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_delayed (struct GNUNET_TIME_Relative delay,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
return GNUNET_SCHEDULER_add_delayed_with_priority (delay,
GNUNET_SCHEDULER_PRIORITY_DEFAULT,
task, task_cls);
}
/**
* Schedule a new task to be run as soon as possible. The task
* will be run with the DEFAULT priority.
*
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_now (GNUNET_SCHEDULER_Task task, void *task_cls)
{
return GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_ZERO, task, task_cls);
}
/**
* Schedule a new task to be run as soon as possible with the
* (transitive) ignore-shutdown flag either explicitly set or
* explicitly enabled. This task (and all tasks created from it,
* other than by another call to this function) will either count or
* not count for the 'lifeness' of the process. This API is only
* useful in a few special cases.
*
* @param lifeness GNUNET_YES if the task counts for lifeness, GNUNET_NO if not.
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_now_with_lifeness (int lifeness,
GNUNET_SCHEDULER_Task task,
void *task_cls)
{
GNUNET_SCHEDULER_TaskIdentifier ret;
ret =
GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
GNUNET_TIME_UNIT_ZERO, NULL, NULL, task,
task_cls);
GNUNET_assert (pending->id == ret);
pending->lifeness = lifeness;
return ret;
}
/**
* Schedule a new task to be run with a specified delay or when any of
* the specified file descriptor sets is ready. The delay can be used
* as a timeout on the socket(s) being ready. The task will be
* scheduled for execution once either the delay has expired or any of
* the socket operations is ready. This is the most general
* function of the "add" family. Note that the "prerequisite_task"
* must be satisfied in addition to any of the other conditions. In
* other words, the task will be started when
*
* (prerequisite-run)
* && (delay-ready
* || any-rs-ready
* || any-ws-ready
* || shutdown-active )
*
*
* @param delay how long should we wait? Use GNUNET_TIME_UNIT_FOREVER_REL for "forever",
* which means that the task will only be run after we receive SIGTERM
* @param priority priority to use
* @param rfd file descriptor we want to read (can be -1)
* @param wfd file descriptors we want to write (can be -1)
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
#ifndef MINGW
static GNUNET_SCHEDULER_TaskIdentifier
add_without_sets (struct GNUNET_TIME_Relative delay,
enum GNUNET_SCHEDULER_Priority priority,
int rfd, int wfd,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
struct Task *t;
#if EXECINFO
void *backtrace_array[MAX_TRACE_DEPTH];
#endif
GNUNET_assert (active_task != NULL);
GNUNET_assert (NULL != task);
t = GNUNET_malloc (sizeof (struct Task));
t->callback = task;
t->callback_cls = task_cls;
#if EXECINFO
t->num_backtrace_strings = backtrace (backtrace_array, MAX_TRACE_DEPTH);
t->backtrace_strings =
backtrace_symbols (backtrace_array, t->num_backtrace_strings);
#endif
#if DEBUG_FDS
if (-1 != rfd)
{
int flags = fcntl (rfd, F_GETFD);
if ((flags == -1) && (errno == EBADF))
{
LOG (GNUNET_ERROR_TYPE_ERROR, "Got invalid file descriptor %d!\n", rfd);
#if EXECINFO
int i;
for (i = 0; i < t->num_backtrace_strings; i++)
LOG (GNUNET_ERROR_TYPE_DEBUG, "Trace: %s\n", t->backtrace_strings[i]);
#endif
GNUNET_assert (0);
}
}
if (-1 != wfd)
{
int flags = fcntl (wfd, F_GETFD);
if (flags == -1 && errno == EBADF)
{
LOG (GNUNET_ERROR_TYPE_ERROR, "Got invalid file descriptor %d!\n", wfd);
#if EXECINFO
int i;
for (i = 0; i < t->num_backtrace_strings; i++)
LOG (GNUNET_ERROR_TYPE_DEBUG, "Trace: %s\n", t->backtrace_strings[i]);
#endif
GNUNET_assert (0);
}
}
#endif
t->read_fd = rfd;
GNUNET_assert (wfd >= -1);
t->write_fd = wfd;
t->id = ++last_id;
#if PROFILE_DELAYS
t->start_time = GNUNET_TIME_absolute_get ();
#endif
t->timeout = GNUNET_TIME_relative_to_absolute (delay);
t->priority = check_priority ((priority == GNUNET_SCHEDULER_PRIORITY_KEEP) ? current_priority : priority);
t->lifeness = current_lifeness;
t->next = pending;
pending = t;
max_priority_added = GNUNET_MAX (max_priority_added, t->priority);
LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding task: %llu / %p\n", t->id,
t->callback_cls);
#if EXECINFO
int i;
for (i = 0; i < t->num_backtrace_strings; i++)
LOG (GNUNET_ERROR_TYPE_DEBUG, "Task %llu trace %d: %s\n", t->id, i,
t->backtrace_strings[i]);
#endif
return t->id;
}
#endif
/**
* Schedule a new task to be run with a specified delay or when the
* specified file descriptor is ready for reading. The delay can be
* used as a timeout on the socket being ready. The task will be
* scheduled for execution once either the delay has expired or the
* socket operation is ready. It will be run with the DEFAULT priority.
*
* @param delay when should this operation time out? Use
* GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
* @param rfd read file-descriptor
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_read_net (struct GNUNET_TIME_Relative delay,
struct GNUNET_NETWORK_Handle *rfd,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
return GNUNET_SCHEDULER_add_read_net_with_priority (delay,
GNUNET_SCHEDULER_PRIORITY_DEFAULT,
rfd, task, task_cls);
}
/**
* Schedule a new task to be run with a specified priority and to be
* run after the specified delay or when the specified file descriptor
* is ready for reading. The delay can be used as a timeout on the
* socket being ready. The task will be scheduled for execution once
* either the delay has expired or the socket operation is ready. It
* will be run with the DEFAULT priority.
*
* @param delay when should this operation time out? Use
* GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
* @param priority priority to use for the task
* @param rfd read file-descriptor
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_read_net_with_priority (struct GNUNET_TIME_Relative delay,
enum GNUNET_SCHEDULER_Priority priority,
struct GNUNET_NETWORK_Handle *rfd,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
#if MINGW
struct GNUNET_NETWORK_FDSet *rs;
GNUNET_SCHEDULER_TaskIdentifier ret;
GNUNET_assert (rfd != NULL);
rs = GNUNET_NETWORK_fdset_create ();
GNUNET_NETWORK_fdset_set (rs, rfd);
ret =
GNUNET_SCHEDULER_add_select (priority,
delay, rs, NULL,
task, task_cls);
GNUNET_NETWORK_fdset_destroy (rs);
return ret;
#else
return add_without_sets (delay,
priority,
GNUNET_NETWORK_get_fd (rfd), -1, task,
task_cls);
#endif
}
/**
* Schedule a new task to be run with a specified delay or when the
* specified file descriptor is ready for writing. The delay can be
* used as a timeout on the socket being ready. The task will be
* scheduled for execution once either the delay has expired or the
* socket operation is ready. It will be run with the priority of
* the calling task.
*
* @param delay when should this operation time out? Use
* GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
* @param wfd write file-descriptor
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_write_net (struct GNUNET_TIME_Relative delay,
struct GNUNET_NETWORK_Handle *wfd,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
#if MINGW
struct GNUNET_NETWORK_FDSet *ws;
GNUNET_SCHEDULER_TaskIdentifier ret;
GNUNET_assert (wfd != NULL);
ws = GNUNET_NETWORK_fdset_create ();
GNUNET_NETWORK_fdset_set (ws, wfd);
ret =
GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
delay, NULL, ws,
task, task_cls);
GNUNET_NETWORK_fdset_destroy (ws);
return ret;
#else
GNUNET_assert (GNUNET_NETWORK_get_fd (wfd) >= 0);
return add_without_sets (delay,
GNUNET_SCHEDULER_PRIORITY_DEFAULT,
-1, GNUNET_NETWORK_get_fd (wfd), task,
task_cls);
#endif
}
/**
* Schedule a new task to be run with a specified delay or when the
* specified file descriptor is ready for reading. The delay can be
* used as a timeout on the socket being ready. The task will be
* scheduled for execution once either the delay has expired or the
* socket operation is ready. It will be run with the DEFAULT priority.
*
* @param delay when should this operation time out? Use
* GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
* @param rfd read file-descriptor
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_read_file (struct GNUNET_TIME_Relative delay,
const struct GNUNET_DISK_FileHandle *rfd,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
#if MINGW
struct GNUNET_NETWORK_FDSet *rs;
GNUNET_SCHEDULER_TaskIdentifier ret;
GNUNET_assert (rfd != NULL);
rs = GNUNET_NETWORK_fdset_create ();
GNUNET_NETWORK_fdset_handle_set (rs, rfd);
ret =
GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
delay, rs, NULL,
task, task_cls);
GNUNET_NETWORK_fdset_destroy (rs);
return ret;
#else
int fd;
GNUNET_DISK_internal_file_handle_ (rfd, &fd, sizeof (int));
return add_without_sets (delay,
GNUNET_SCHEDULER_PRIORITY_DEFAULT,
fd, -1, task, task_cls);
#endif
}
/**
* Schedule a new task to be run with a specified delay or when the
* specified file descriptor is ready for writing. The delay can be
* used as a timeout on the socket being ready. The task will be
* scheduled for execution once either the delay has expired or the
* socket operation is ready. It will be run with the DEFAULT priority.
*
* @param delay when should this operation time out? Use
* GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
* @param wfd write file-descriptor
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_write_file (struct GNUNET_TIME_Relative delay,
const struct GNUNET_DISK_FileHandle *wfd,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
#if MINGW
struct GNUNET_NETWORK_FDSet *ws;
GNUNET_SCHEDULER_TaskIdentifier ret;
GNUNET_assert (wfd != NULL);
ws = GNUNET_NETWORK_fdset_create ();
GNUNET_NETWORK_fdset_handle_set (ws, wfd);
ret =
GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
delay, NULL, ws,
task, task_cls);
GNUNET_NETWORK_fdset_destroy (ws);
return ret;
#else
int fd;
GNUNET_DISK_internal_file_handle_ (wfd, &fd, sizeof (int));
GNUNET_assert (fd >= 0);
return add_without_sets (delay,
GNUNET_SCHEDULER_PRIORITY_DEFAULT,
-1, fd, task, task_cls);
#endif
}
/**
* Schedule a new task to be run with a specified delay or when any of
* the specified file descriptor sets is ready. The delay can be used
* as a timeout on the socket(s) being ready. The task will be
* scheduled for execution once either the delay has expired or any of
* the socket operations is ready. This is the most general
* function of the "add" family. Note that the "prerequisite_task"
* must be satisfied in addition to any of the other conditions. In
* other words, the task will be started when
*
* (prerequisite-run)
* && (delay-ready
* || any-rs-ready
* || any-ws-ready
* || (shutdown-active && run-on-shutdown) )
*
*
* @param prio how important is this task?
* @param delay how long should we wait? Use GNUNET_TIME_UNIT_FOREVER_REL for "forever",
* which means that the task will only be run after we receive SIGTERM
* @param rs set of file descriptors we want to read (can be NULL)
* @param ws set of file descriptors we want to write (can be NULL)
* @param task main function of the task
* @param task_cls closure of task
* @return unique task identifier for the job
* only valid until "task" is started!
*/
GNUNET_SCHEDULER_TaskIdentifier
GNUNET_SCHEDULER_add_select (enum GNUNET_SCHEDULER_Priority prio,
struct GNUNET_TIME_Relative delay,
const struct GNUNET_NETWORK_FDSet *rs,
const struct GNUNET_NETWORK_FDSet *ws,
GNUNET_SCHEDULER_Task task, void *task_cls)
{
struct Task *t;
#if EXECINFO
void *backtrace_array[MAX_TRACE_DEPTH];
#endif
GNUNET_assert (NULL != active_task);
GNUNET_assert (NULL != task);
t = GNUNET_malloc (sizeof (struct Task));
t->callback = task;
t->callback_cls = task_cls;
#if EXECINFO
t->num_backtrace_strings = backtrace (backtrace_array, MAX_TRACE_DEPTH);
t->backtrace_strings =
backtrace_symbols (backtrace_array, t->num_backtrace_strings);
#endif
t->read_fd = -1;
t->write_fd = -1;
if (rs != NULL)
{
t->read_set = GNUNET_NETWORK_fdset_create ();
GNUNET_NETWORK_fdset_copy (t->read_set, rs);
}
if (ws != NULL)
{
t->write_set = GNUNET_NETWORK_fdset_create ();
GNUNET_NETWORK_fdset_copy (t->write_set, ws);
}
t->id = ++last_id;
#if PROFILE_DELAYS
t->start_time = GNUNET_TIME_absolute_get ();
#endif
t->timeout = GNUNET_TIME_relative_to_absolute (delay);
t->priority =
check_priority ((prio ==
GNUNET_SCHEDULER_PRIORITY_KEEP) ? current_priority :
prio);
t->lifeness = current_lifeness;
t->next = pending;
pending = t;
max_priority_added = GNUNET_MAX (max_priority_added, t->priority);
LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding task: %llu / %p\n", t->id,
t->callback_cls);
#if EXECINFO
int i;
for (i = 0; i < t->num_backtrace_strings; i++)
LOG (GNUNET_ERROR_TYPE_DEBUG, "Task %llu trace %d: %s\n", t->id, i,
t->backtrace_strings[i]);
#endif
return t->id;
}
/* end of scheduler.c */