*
* \param s Pointer to the scheduler struct.
*
- * This function updates the global \a now pointer, calls all registered
+ * This function updates the global now pointer, calls all registered
* pre_monitor hooks which may set the timeout and add any file descriptors to
- * the fd sets of \a s. Next, it calls para_select() and makes the result
+ * the pollfd array. Next, it calls the poll function and makes the result
* available to the registered tasks by calling their post_monitor hook.
*
* \return Zero if no more tasks are left in the task list, negative if the
- * select function returned an error.
+ * poll function returned an error.
*
* \sa \ref now.
*/
int ret;
unsigned num_running_tasks;
- if (!s->select_function)
- s->select_function = para_select;
+ if (!s->poll_function)
+ s->poll_function = xpoll;
again:
- FD_ZERO(&s->rfds);
- FD_ZERO(&s->wfds);
+ s->num_pfds = 0;
+ if (s->pidx)
+ memset(s->pidx, 0xff, s->pidx_array_len * sizeof(unsigned));
s->timeout = s->default_timeout;
- s->max_fileno = -1;
clock_get_realtime(&now_struct);
sched_pre_monitor(s);
- ret = s->select_function(s->max_fileno + 1, &s->rfds, &s->wfds,
- s->timeout);
+ ret = s->poll_function(s->pfd, s->num_pfds, s->timeout);
if (ret < 0)
return ret;
- if (ret == 0) {
- /*
- * APUE: Be careful not to check the descriptor sets on return
- * unless the return value is greater than zero. The return
- * state of the descriptor sets is implementation dependent if
- * either a signal is caught or the timer expires.
- */
- FD_ZERO(&s->rfds);
- FD_ZERO(&s->wfds);
- }
clock_get_realtime(&now_struct);
num_running_tasks = sched_post_monitor(s);
if (num_running_tasks == 0)
t->name);
unlink_and_free_task(t);
}
+ free(s->pfd);
+ free(s->pidx);
}
/**
*/
struct task *task_register(struct task_info *info, struct sched *s)
{
- struct task *t = para_malloc(sizeof(*t));
+ struct task *t = alloc(sizeof(*t));
assert(info->post_monitor);
}
/**
- * Set the select timeout to the minimal possible value.
+ * Set the I/O timeout to the minimal possible value.
*
* \param s Pointer to the scheduler struct.
*
- * This causes the next select() call to return immediately.
+ * This causes the next poll() call to return immediately.
*/
void sched_min_delay(struct sched *s)
{
}
/**
- * Impose an upper bound for the timeout of the next select() call.
+ * Impose an upper bound for the I/O timeout.
*
* \param to Maximal allowed timeout.
* \param s Pointer to the scheduler struct.
*
- * If the current scheduler timeout is already smaller than \a to, this
- * function does nothing. Otherwise the timeout for the next select() call is
- * set to the given value.
+ * If the current I/O timeout is already smaller than to, this function does
+ * nothing. Otherwise the timeout is set to the given value.
*
* \sa \ref sched_request_timeout_ms().
*/
}
/**
- * Force the next select() call to return before the given amount of milliseconds.
+ * Bound the I/O timeout to at most the given amount of milliseconds.
*
* \param ms The maximal allowed timeout in milliseconds.
* \param s Pointer to the scheduler struct.
*
- * Like sched_request_timeout() this imposes an upper bound on the timeout
- * value for the next select() call.
+ * Like \ref sched_request_timeout() this imposes an upper bound on the I/O
+ * timeout.
*/
void sched_request_timeout_ms(long unsigned ms, struct sched *s)
{
}
/**
- * Force the next select() call to return before the given future time.
+ * Bound the I/O timeout by an absolute time in the future.
*
- * \param barrier Absolute time before select() should return.
+ * \param barrier Defines the upper bound for the timeout.
* \param s Pointer to the scheduler struct.
*
- * \return If \a barrier is in the past, this function does nothing and returns
- * zero. Otherwise it returns one.
+ * \return If the barrier is in the past, this function does nothing and
+ * returns zero. Otherwise it returns one.
*
* \sa \ref sched_request_barrier_or_min_delay().
*/
}
/**
- * Force the next select() call to return before the given time.
+ * Bound the I/O timeout or request a minimal delay.
*
- * \param barrier Absolute time before select() should return.
+ * \param barrier Absolute time as in \ref sched_request_barrier().
* \param s Pointer to the scheduler struct.
*
- * \return If \a barrier is in the past, this function requests a minimal
+ * \return If the barrier is in the past, this function requests a minimal
* timeout and returns zero. Otherwise it returns one.
*
* \sa \ref sched_min_delay(), \ref sched_request_barrier().
return 1;
}
-static void sched_fd_set(int fd, fd_set *fds, int *max_fileno)
+static void add_pollfd(int fd, struct sched *s, short events)
{
- assert(fd >= 0 && fd < FD_SETSIZE);
+ assert(fd >= 0);
#if 0
{
int flags = fcntl(fd, F_GETFL);
}
}
#endif
- FD_SET(fd, fds);
- *max_fileno = PARA_MAX(*max_fileno, fd);
+ if (s->pidx_array_len > fd) { /* is fd already registered? */
+ if (s->pidx[fd] < s->pfd_array_len) { /* yes, it is */
+ assert(s->pfd[s->pidx[fd]].fd == fd);
+ s->pfd[s->pidx[fd]].events |= events;
+ return;
+ }
+ } else { /* need to extend the index array */
+ unsigned old_len = s->pidx_array_len;
+ while (s->pidx_array_len <= fd)
+ s->pidx_array_len = s->pidx_array_len * 2 + 1;
+ PARA_INFO_LOG("pidx array len: %u\n", s->pidx_array_len);
+ s->pidx = para_realloc(s->pidx,
+ s->pidx_array_len * sizeof(unsigned));
+ memset(s->pidx + old_len, 0xff,
+ (s->pidx_array_len - old_len) * sizeof(unsigned));
+ }
+ /*
+ * The given fd is not part of the pfd array yet. Initialize pidx[fd]
+ * to point at the next unused slot of this array and initialize the
+ * slot.
+ */
+ s->pidx[fd] = s->num_pfds;
+ if (s->pfd_array_len <= s->num_pfds) {
+ unsigned old_len = s->pfd_array_len;
+ s->pfd_array_len = old_len * 2 + 1;
+ PARA_INFO_LOG("pfd array len: %u\n", s->pfd_array_len);
+ s->pfd = para_realloc(s->pfd,
+ s->pfd_array_len * sizeof(struct pollfd));
+ memset(s->pfd + old_len, 0,
+ (s->pfd_array_len - old_len) * sizeof(struct pollfd));
+ }
+ s->pfd[s->num_pfds].fd = fd;
+ s->pfd[s->num_pfds].events = events;
+ s->pfd[s->num_pfds].revents = 0;
+ s->num_pfds++;
}
/**
*/
void sched_monitor_readfd(int fd, struct sched *s)
{
- sched_fd_set(fd, &s->rfds, &s->max_fileno);
+ add_pollfd(fd, s, POLLIN);
}
/**
*/
void sched_monitor_writefd(int fd, struct sched *s)
{
- sched_fd_set(fd, &s->wfds, &s->max_fileno);
+ add_pollfd(fd, s, POLLOUT);
+}
+
+static int get_revents(int fd, const struct sched *s)
+{
+ if (fd < 0)
+ return 0;
+ if (fd >= s->pidx_array_len)
+ return 0;
+ if (s->pidx[fd] >= s->num_pfds)
+ return 0;
+ if (s->pfd[s->pidx[fd]].fd != fd)
+ return 0;
+ assert((s->pfd[s->pidx[fd]].revents & POLLNVAL) == 0);
+ return s->pfd[s->pidx[fd]].revents;
+}
+
+/**
+ * Check whether there is data to read on the given fd.
+ *
+ * To be called from the ->post_monitor() method of a task.
+ *
+ * \param fd Should have been monitored with \ref sched_monitor_readfd().
+ * \param s The scheduler instance.
+ *
+ * \return True if the file descriptor is ready for reading, false otherwise.
+ * If fd is negative, or has not been monitored in the current iteration of the
+ * scheduler's main loop, the function also returns false.
+ *
+ * \sa \ref sched_write_ok().
+ */
+bool sched_read_ok(int fd, const struct sched *s)
+{
+ return get_revents(fd, s) & (POLLIN | POLLERR | POLLHUP);
+}
+
+/**
+ * Check whether writing is possible (i.e., does not block).
+ *
+ * \param fd Should have been monitored with \ref sched_monitor_writefd().
+ * \param s The scheduler instance.
+ *
+ * \return True if the file descriptor is ready for writing, false otherwise.
+ * The comment in \ref sched_read_ok() about invalid file descriptors applies
+ * to this function as well.
+ */
+bool sched_write_ok(int fd, const struct sched *s)
+{
+ return get_revents(fd, s) & (POLLOUT | POLLERR | POLLHUP);
}