Mercurial > dovecot > core-2.2
view src/lib/ioloop.c @ 12713:16ce45dbcb53
ioloop: Use -1 for infinite poll/epoll timeout rather than INT_MAX.
Should improve performance a tiny bit and also works around a CPU eater bug
in Linux 2.6.37.
author | Timo Sirainen <tss@iki.fi> |
---|---|
date | Wed, 26 Jan 2011 21:47:52 +0200 |
parents | 8fa2c23e9256 |
children | baa0314ed610 44d0474a451e |
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/* Copyright (c) 2002-2010 Dovecot authors, see the included COPYING file */ #include "lib.h" #include "time-util.h" #include "ioloop-internal.h" #include <unistd.h> #define timer_is_larger(tvp, uvp) \ ((tvp)->tv_sec > (uvp)->tv_sec || \ ((tvp)->tv_sec == (uvp)->tv_sec && \ (tvp)->tv_usec > (uvp)->tv_usec)) time_t ioloop_time = 0; struct timeval ioloop_timeval; struct ioloop *current_ioloop = NULL; static void io_loop_initialize_handler(struct ioloop *ioloop) { unsigned int initial_fd_count; initial_fd_count = ioloop->max_fd_count > 0 && ioloop->max_fd_count < IOLOOP_INITIAL_FD_COUNT ? ioloop->max_fd_count : IOLOOP_INITIAL_FD_COUNT; io_loop_handler_init(ioloop, initial_fd_count); } #undef io_add struct io *io_add(int fd, enum io_condition condition, io_callback_t *callback, void *context) { struct io_file *io; i_assert(fd >= 0); i_assert(callback != NULL); i_assert((condition & IO_NOTIFY) == 0); io = i_new(struct io_file, 1); io->io.condition = condition; io->io.callback = callback; io->io.context = context; io->io.ioloop = current_ioloop; io->refcount = 1; io->fd = fd; if (io->io.ioloop->cur_log != NULL) { io->io.log = io->io.ioloop->cur_log; io_loop_log_ref(io->io.log); } if (io->io.ioloop->handler_context == NULL) io_loop_initialize_handler(io->io.ioloop); io_loop_handle_add(io); if (io->io.ioloop->io_files != NULL) { io->io.ioloop->io_files->prev = io; io->next = io->io.ioloop->io_files; } io->io.ioloop->io_files = io; return &io->io; } static void io_file_unlink(struct io_file *io) { if (io->prev != NULL) io->prev->next = io->next; else io->io.ioloop->io_files = io->next; if (io->next != NULL) io->next->prev = io->prev; /* if we got here from an I/O handler callback, make sure we don't try to handle this one next. */ if (io->io.ioloop->next_io_file == io) io->io.ioloop->next_io_file = io->next; } static void io_remove_full(struct io **_io, bool closed) { struct io *io = *_io; i_assert(io->callback != NULL); *_io = NULL; /* make sure the callback doesn't get called anymore. kqueue code relies on this. */ io->callback = NULL; if (io->log != NULL) io_loop_log_unref(&io->log); if ((io->condition & IO_NOTIFY) != 0) io_loop_notify_remove(io); else { struct io_file *io_file = (struct io_file *)io; io_file_unlink(io_file); io_loop_handle_remove(io_file, closed); } } void io_remove(struct io **io) { io_remove_full(io, FALSE); } void io_remove_closed(struct io **io) { i_assert(((*io)->condition & IO_NOTIFY) == 0); io_remove_full(io, TRUE); } static void timeout_update_next(struct timeout *timeout, struct timeval *tv_now) { if (tv_now == NULL) { if (gettimeofday(&timeout->next_run, NULL) < 0) i_fatal("gettimeofday(): %m"); } else { timeout->next_run.tv_sec = tv_now->tv_sec; timeout->next_run.tv_usec = tv_now->tv_usec; } /* we don't want microsecond accuracy or this function will be called all the time - millisecond is more than enough */ timeout->next_run.tv_usec -= timeout->next_run.tv_usec % 1000; timeout->next_run.tv_sec += timeout->msecs/1000; timeout->next_run.tv_usec += (timeout->msecs%1000)*1000; if (timeout->next_run.tv_usec > 1000000) { timeout->next_run.tv_sec++; timeout->next_run.tv_usec -= 1000000; } } #undef timeout_add struct timeout *timeout_add(unsigned int msecs, timeout_callback_t *callback, void *context) { struct timeout *timeout; timeout = i_new(struct timeout, 1); timeout->msecs = msecs; timeout->ioloop = current_ioloop; timeout->callback = callback; timeout->context = context; if (timeout->ioloop->cur_log != NULL) { timeout->log = timeout->ioloop->cur_log; io_loop_log_ref(timeout->log); } timeout_update_next(timeout, timeout->ioloop->running ? NULL : &ioloop_timeval); priorityq_add(timeout->ioloop->timeouts, &timeout->item); return timeout; } static void timeout_free(struct timeout *timeout) { if (timeout->log != NULL) io_loop_log_unref(&timeout->log); i_free(timeout); } void timeout_remove(struct timeout **_timeout) { struct timeout *timeout = *_timeout; *_timeout = NULL; priorityq_remove(timeout->ioloop->timeouts, &timeout->item); timeout_free(timeout); } static void timeout_reset_timeval(struct timeout *timeout, struct timeval *tv_now) { timeout_update_next(timeout, tv_now); if (timeout->msecs == 0) { /* if we came here from io_loop_handle_timeouts(), next_run must be larger than tv_now or we could go to infinite loop. +1000 to get 1 ms further, another +1000 to account for timeout_update_next()'s truncation. */ timeout->next_run.tv_usec += 2000; if (timeout->next_run.tv_usec >= 1000000) { timeout->next_run.tv_sec++; timeout->next_run.tv_usec -= 1000000; } } i_assert(tv_now == NULL || timeout->next_run.tv_sec > tv_now->tv_sec || (timeout->next_run.tv_sec == tv_now->tv_sec && timeout->next_run.tv_usec > tv_now->tv_usec)); priorityq_remove(timeout->ioloop->timeouts, &timeout->item); priorityq_add(timeout->ioloop->timeouts, &timeout->item); } void timeout_reset(struct timeout *timeout) { timeout_reset_timeval(timeout, timeout->ioloop->running ? NULL : &ioloop_timeval); } static int timeout_get_wait_time(struct timeout *timeout, struct timeval *tv_r, struct timeval *tv_now) { int ret; if (tv_now->tv_sec == 0) { if (gettimeofday(tv_now, NULL) < 0) i_fatal("gettimeofday(): %m"); } tv_r->tv_sec = tv_now->tv_sec; tv_r->tv_usec = tv_now->tv_usec; i_assert(tv_r->tv_sec > 0); i_assert(timeout->next_run.tv_sec > 0); tv_r->tv_sec = timeout->next_run.tv_sec - tv_r->tv_sec; tv_r->tv_usec = timeout->next_run.tv_usec - tv_r->tv_usec; if (tv_r->tv_usec < 0) { tv_r->tv_sec--; tv_r->tv_usec += 1000000; } if (tv_r->tv_sec < 0 || (tv_r->tv_sec == 0 && tv_r->tv_usec < 1000)) { tv_r->tv_sec = 0; tv_r->tv_usec = 0; return 0; } if (tv_r->tv_sec > INT_MAX/1000-1) tv_r->tv_sec = INT_MAX/1000-1; /* round wait times up to next millisecond */ ret = tv_r->tv_sec * 1000 + (tv_r->tv_usec + 999) / 1000; i_assert(ret > 0 && tv_r->tv_sec >= 0 && tv_r->tv_usec >= 0); return ret; } int io_loop_get_wait_time(struct ioloop *ioloop, struct timeval *tv_r) { struct timeval tv_now; struct priorityq_item *item; struct timeout *timeout; int msecs; item = priorityq_peek(ioloop->timeouts); timeout = (struct timeout *)item; if (timeout == NULL) { /* no timeouts. use INT_MAX msecs for timeval and return -1 for poll/epoll infinity. */ tv_r->tv_sec = INT_MAX / 1000; tv_r->tv_usec = 0; ioloop->next_max_time = (1ULL << (TIME_T_MAX_BITS-1)) - 1; return -1; } tv_now.tv_sec = 0; msecs = timeout_get_wait_time(timeout, tv_r, &tv_now); ioloop->next_max_time = (tv_now.tv_sec + msecs/1000) + 1; return msecs; } static int timeout_cmp(const void *p1, const void *p2) { const struct timeout *to1 = p1, *to2 = p2; return timeval_cmp(&to1->next_run, &to2->next_run); } static void io_loop_default_time_moved(time_t old_time, time_t new_time) { if (old_time > new_time) { i_warning("Time moved backwards by %ld seconds.", (long)(old_time - new_time)); } } static void io_loop_timeouts_update(struct ioloop *ioloop, long diff_secs) { struct priorityq_item *const *items; unsigned int i, count; count = priorityq_count(ioloop->timeouts); items = priorityq_items(ioloop->timeouts); for (i = 0; i < count; i++) { struct timeout *to = (struct timeout *)items[i]; to->next_run.tv_sec += diff_secs; } } static void io_loops_timeouts_update(long diff_secs) { struct ioloop *ioloop; for (ioloop = current_ioloop; ioloop != NULL; ioloop = ioloop->prev) io_loop_timeouts_update(ioloop, diff_secs); } static void io_loop_handle_timeouts_real(struct ioloop *ioloop) { struct priorityq_item *item; struct timeval tv, tv_call; unsigned int t_id; if (gettimeofday(&ioloop_timeval, NULL) < 0) i_fatal("gettimeofday(): %m"); /* Don't bother comparing usecs. */ if (unlikely(ioloop_time > ioloop_timeval.tv_sec)) { /* time moved backwards */ io_loops_timeouts_update(-(long)(ioloop_time - ioloop_timeval.tv_sec)); ioloop->time_moved_callback(ioloop_time, ioloop_timeval.tv_sec); /* the callback may have slept, so check the time again. */ if (gettimeofday(&ioloop_timeval, NULL) < 0) i_fatal("gettimeofday(): %m"); } else if (unlikely(ioloop_timeval.tv_sec > ioloop->next_max_time)) { io_loops_timeouts_update(ioloop_timeval.tv_sec - ioloop->next_max_time); /* time moved forwards */ ioloop->time_moved_callback(ioloop->next_max_time, ioloop_timeval.tv_sec); } ioloop_time = ioloop_timeval.tv_sec; tv_call = ioloop_timeval; while ((item = priorityq_peek(ioloop->timeouts)) != NULL) { struct timeout *timeout = (struct timeout *)item; /* use tv_call to make sure we don't get to infinite loop in case callbacks update ioloop_timeval. */ if (timeout_get_wait_time(timeout, &tv, &tv_call) > 0) break; /* update timeout's next_run and reposition it in the queue */ timeout_reset_timeval(timeout, &tv_call); if (timeout->log != NULL) { ioloop->cur_log = timeout->log; io_loop_log_ref(ioloop->cur_log); i_set_failure_prefix(timeout->log->prefix); } t_id = t_push(); timeout->callback(timeout->context); if (t_pop() != t_id) { i_panic("Leaked a t_pop() call in timeout handler %p", (void *)timeout->callback); } if (ioloop->cur_log != NULL) { io_loop_log_unref(&ioloop->cur_log); i_set_failure_prefix(ioloop->default_log_prefix); } } } void io_loop_handle_timeouts(struct ioloop *ioloop) { T_BEGIN { io_loop_handle_timeouts_real(ioloop); } T_END; } void io_loop_call_io(struct io *io) { struct ioloop *ioloop = io->ioloop; unsigned int t_id; if (io->log != NULL) { ioloop->cur_log = io->log; io_loop_log_ref(ioloop->cur_log); i_set_failure_prefix(io->log->prefix); } t_id = t_push(); io->callback(io->context); if (t_pop() != t_id) { i_panic("Leaked a t_pop() call in I/O handler %p", (void *)io->callback); } if (ioloop->cur_log != NULL) { io_loop_log_unref(&ioloop->cur_log); i_set_failure_prefix(ioloop->default_log_prefix); } } void io_loop_run(struct ioloop *ioloop) { if (ioloop->handler_context == NULL) io_loop_initialize_handler(ioloop); if (ioloop->cur_log != NULL) io_loop_log_unref(&ioloop->cur_log); ioloop->running = TRUE; while (ioloop->running) io_loop_handler_run(ioloop); } void io_loop_stop(struct ioloop *ioloop) { ioloop->running = FALSE; } void io_loop_set_running(struct ioloop *ioloop) { ioloop->running = TRUE; } void io_loop_set_max_fd_count(struct ioloop *ioloop, unsigned int max_fds) { ioloop->max_fd_count = max_fds; } bool io_loop_is_running(struct ioloop *ioloop) { return ioloop->running; } struct ioloop *io_loop_create(void) { struct ioloop *ioloop; /* initialize time */ if (gettimeofday(&ioloop_timeval, NULL) < 0) i_fatal("gettimeofday(): %m"); ioloop_time = ioloop_timeval.tv_sec; ioloop = i_new(struct ioloop, 1); ioloop->timeouts = priorityq_init(timeout_cmp, 32); ioloop->time_moved_callback = current_ioloop != NULL ? current_ioloop->time_moved_callback : io_loop_default_time_moved; ioloop->prev = current_ioloop; current_ioloop = ioloop; return ioloop; } void io_loop_destroy(struct ioloop **_ioloop) { struct ioloop *ioloop = *_ioloop; struct priorityq_item *item; *_ioloop = NULL; if (ioloop->notify_handler_context != NULL) io_loop_notify_handler_deinit(ioloop); while (ioloop->io_files != NULL) { struct io_file *io = ioloop->io_files; struct io *_io = &io->io; i_warning("I/O leak: %p (%d)", (void *)io->io.callback, io->fd); io_remove(&_io); } while ((item = priorityq_pop(ioloop->timeouts)) != NULL) { struct timeout *to = (struct timeout *)item; i_warning("Timeout leak: %p", (void *)to->callback); timeout_free(to); } priorityq_deinit(&ioloop->timeouts); if (ioloop->handler_context != NULL) io_loop_handler_deinit(ioloop); /* ->prev won't work unless loops are destroyed in create order */ i_assert(ioloop == current_ioloop); current_ioloop = current_ioloop->prev; i_free(ioloop); } void io_loop_set_time_moved_callback(struct ioloop *ioloop, io_loop_time_moved_callback_t *callback) { ioloop->time_moved_callback = callback; } void io_loop_set_current(struct ioloop *ioloop) { current_ioloop = ioloop; } struct ioloop_log *io_loop_log_new(struct ioloop *ioloop) { struct ioloop_log *log; i_assert(ioloop->default_log_prefix != NULL); log = i_new(struct ioloop_log, 1); log->refcount = 2; log->prefix = i_strdup(""); log->ioloop = ioloop; if (ioloop->cur_log != NULL) io_loop_log_unref(&ioloop->cur_log); ioloop->cur_log = log; return log; } void io_loop_log_ref(struct ioloop_log *log) { i_assert(log->refcount > 0); log->refcount++; } void io_loop_log_unref(struct ioloop_log **_log) { struct ioloop_log *log = *_log; *_log = NULL; i_assert(log->refcount > 0); if (--log->refcount > 0) return; /* cur_log itself keeps a reference */ i_assert(log->ioloop->cur_log != log); i_free(log->prefix); i_free(log); } void io_loop_log_set_prefix(struct ioloop_log *log, const char *prefix) { i_free(log->prefix); log->prefix = i_strdup(prefix); } void io_loop_set_default_log_prefix(struct ioloop *ioloop, const char *prefix) { i_assert(prefix != NULL); i_free(ioloop->default_log_prefix); ioloop->default_log_prefix = i_strdup(prefix); }