blob: 03d32b008947d50d092dae800336a1941eab3da9 [file] [log] [blame]
/*
* FD polling functions for generic poll()
*
* Copyright 2000-2014 Willy Tarreau <w@1wt.eu>
*
* This program 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 of the License, or (at your option) any later version.
*
*/
#define _GNU_SOURCE // for POLLRDHUP on Linux
#include <unistd.h>
#include <poll.h>
#include <sys/time.h>
#include <sys/types.h>
#include <haproxy/activity.h>
#include <haproxy/api.h>
#include <haproxy/fd.h>
#include <haproxy/global.h>
#include <haproxy/ticks.h>
#include <haproxy/time.h>
#ifndef POLLRDHUP
/* POLLRDHUP was defined late in libc, and it appeared in kernel 2.6.17 */
#define POLLRDHUP 0
#endif
static int maxfd; /* # of the highest fd + 1 */
static unsigned int *fd_evts[2];
/* private data */
static THREAD_LOCAL int nbfd = 0;
static THREAD_LOCAL struct pollfd *poll_events = NULL;
static void __fd_clo(int fd)
{
hap_fd_clr(fd, fd_evts[DIR_RD]);
hap_fd_clr(fd, fd_evts[DIR_WR]);
}
static void _update_fd(int fd, int *max_add_fd)
{
int en;
en = fdtab[fd].state;
/* we have a single state for all threads, which is why we
* don't check the tid_bit. First thread to see the update
* takes it for every other one.
*/
if (!(en & FD_EV_ACTIVE_RW)) {
if (!(polled_mask[fd].poll_recv | polled_mask[fd].poll_send)) {
/* fd was not watched, it's still not */
return;
}
/* fd totally removed from poll list */
hap_fd_clr(fd, fd_evts[DIR_RD]);
hap_fd_clr(fd, fd_evts[DIR_WR]);
_HA_ATOMIC_AND(&polled_mask[fd].poll_recv, 0);
_HA_ATOMIC_AND(&polled_mask[fd].poll_send, 0);
}
else {
/* OK fd has to be monitored, it was either added or changed */
if (!(en & FD_EV_ACTIVE_R)) {
hap_fd_clr(fd, fd_evts[DIR_RD]);
if (polled_mask[fd].poll_recv & tid_bit)
_HA_ATOMIC_AND(&polled_mask[fd].poll_recv, ~tid_bit);
} else {
hap_fd_set(fd, fd_evts[DIR_RD]);
if (!(polled_mask[fd].poll_recv & tid_bit))
_HA_ATOMIC_OR(&polled_mask[fd].poll_recv, tid_bit);
}
if (!(en & FD_EV_ACTIVE_W)) {
hap_fd_clr(fd, fd_evts[DIR_WR]);
if (polled_mask[fd].poll_send & tid_bit)
_HA_ATOMIC_AND(&polled_mask[fd].poll_send, ~tid_bit);
}else {
hap_fd_set(fd, fd_evts[DIR_WR]);
if (!(polled_mask[fd].poll_send & tid_bit))
_HA_ATOMIC_OR(&polled_mask[fd].poll_send, tid_bit);
}
if (fd > *max_add_fd)
*max_add_fd = fd;
}
}
/*
* Poll() poller
*/
static void _do_poll(struct poller *p, int exp, int wake)
{
int status;
int fd;
int wait_time;
int updt_idx;
int fds, count;
int sr, sw;
int old_maxfd, new_maxfd, max_add_fd;
unsigned rn, wn; /* read new, write new */
int old_fd;
max_add_fd = -1;
/* first, scan the update list to find changes */
for (updt_idx = 0; updt_idx < fd_nbupdt; updt_idx++) {
fd = fd_updt[updt_idx];
_HA_ATOMIC_AND(&fdtab[fd].update_mask, ~tid_bit);
if (!fdtab[fd].owner) {
activity[tid].poll_drop++;
continue;
}
_update_fd(fd, &max_add_fd);
}
/* Now scan the global update list */
for (old_fd = fd = update_list.first; fd != -1; fd = fdtab[fd].update.next) {
if (fd == -2) {
fd = old_fd;
continue;
}
else if (fd <= -3)
fd = -fd -4;
if (fd == -1)
break;
if (fdtab[fd].update_mask & tid_bit) {
/* Cheat a bit, as the state is global to all pollers
* we don't need every thread ot take care of the
* update.
*/
_HA_ATOMIC_AND(&fdtab[fd].update_mask, ~all_threads_mask);
done_update_polling(fd);
} else
continue;
if (!fdtab[fd].owner)
continue;
_update_fd(fd, &max_add_fd);
}
/* maybe we added at least one fd larger than maxfd */
for (old_maxfd = maxfd; old_maxfd <= max_add_fd; ) {
if (_HA_ATOMIC_CAS(&maxfd, &old_maxfd, max_add_fd + 1))
break;
}
/* maxfd doesn't need to be precise but it needs to cover *all* active
* FDs. Thus we only shrink it if we have such an opportunity. The algo
* is simple : look for the previous used place, try to update maxfd to
* point to it, abort if maxfd changed in the mean time.
*/
old_maxfd = maxfd;
do {
new_maxfd = old_maxfd;
while (new_maxfd - 1 >= 0 && !fdtab[new_maxfd - 1].owner)
new_maxfd--;
if (new_maxfd >= old_maxfd)
break;
} while (!_HA_ATOMIC_CAS(&maxfd, &old_maxfd, new_maxfd));
thread_harmless_now();
if (sleeping_thread_mask & tid_bit)
_HA_ATOMIC_AND(&sleeping_thread_mask, ~tid_bit);
fd_nbupdt = 0;
nbfd = 0;
for (fds = 0; (fds * 8*sizeof(**fd_evts)) < maxfd; fds++) {
rn = fd_evts[DIR_RD][fds];
wn = fd_evts[DIR_WR][fds];
if (!(rn|wn))
continue;
for (count = 0, fd = fds * 8*sizeof(**fd_evts); count < 8*sizeof(**fd_evts) && fd < maxfd; count++, fd++) {
sr = (rn >> count) & 1;
sw = (wn >> count) & 1;
if ((sr|sw)) {
if (!fdtab[fd].owner) {
/* should normally not happen here except
* due to rare thread concurrency
*/
continue;
}
if (!(fdtab[fd].thread_mask & tid_bit)) {
activity[tid].poll_skip++;
continue;
}
poll_events[nbfd].fd = fd;
poll_events[nbfd].events = (sr ? (POLLIN | POLLRDHUP) : 0) | (sw ? POLLOUT : 0);
nbfd++;
}
}
}
/* now let's wait for events */
wait_time = wake ? 0 : compute_poll_timeout(exp);
tv_entering_poll();
activity_count_runtime();
status = poll(poll_events, nbfd, wait_time);
tv_update_date(wait_time, status);
tv_leaving_poll(wait_time, status);
thread_harmless_end();
for (count = 0; status > 0 && count < nbfd; count++) {
unsigned int n;
int e = poll_events[count].revents;
fd = poll_events[count].fd;
if (!(e & ( POLLOUT | POLLIN | POLLERR | POLLHUP | POLLRDHUP )))
continue;
/* ok, we found one active fd */
status--;
if (!fdtab[fd].owner) {
activity[tid].poll_dead++;
continue;
}
n = ((e & POLLIN) ? FD_EV_READY_R : 0) |
((e & POLLOUT) ? FD_EV_READY_W : 0) |
((e & POLLRDHUP) ? FD_EV_SHUT_R : 0) |
((e & POLLHUP) ? FD_EV_SHUT_RW : 0) |
((e & POLLERR) ? FD_EV_ERR_RW : 0);
if ((e & POLLRDHUP) && !(cur_poller.flags & HAP_POLL_F_RDHUP))
_HA_ATOMIC_OR(&cur_poller.flags, HAP_POLL_F_RDHUP);
fd_update_events(fd, n);
}
}
static int init_poll_per_thread()
{
poll_events = calloc(1, sizeof(struct pollfd) * global.maxsock);
if (poll_events == NULL)
return 0;
return 1;
}
static void deinit_poll_per_thread()
{
free(poll_events);
poll_events = NULL;
}
/*
* Initialization of the poll() poller.
* Returns 0 in case of failure, non-zero in case of success. If it fails, it
* disables the poller by setting its pref to 0.
*/
static int _do_init(struct poller *p)
{
__label__ fail_swevt, fail_srevt;
int fd_evts_bytes;
p->private = NULL;
fd_evts_bytes = (global.maxsock + sizeof(**fd_evts) * 8 - 1) / (sizeof(**fd_evts) * 8) * sizeof(**fd_evts);
if ((fd_evts[DIR_RD] = calloc(1, fd_evts_bytes)) == NULL)
goto fail_srevt;
if ((fd_evts[DIR_WR] = calloc(1, fd_evts_bytes)) == NULL)
goto fail_swevt;
hap_register_per_thread_init(init_poll_per_thread);
hap_register_per_thread_deinit(deinit_poll_per_thread);
return 1;
fail_swevt:
free(fd_evts[DIR_RD]);
fail_srevt:
p->pref = 0;
return 0;
}
/*
* Termination of the poll() poller.
* Memory is released and the poller is marked as unselectable.
*/
static void _do_term(struct poller *p)
{
free(fd_evts[DIR_WR]);
free(fd_evts[DIR_RD]);
p->private = NULL;
p->pref = 0;
}
/*
* Check that the poller works.
* Returns 1 if OK, otherwise 0.
*/
static int _do_test(struct poller *p)
{
return 1;
}
/*
* It is a constructor, which means that it will automatically be called before
* main(). This is GCC-specific but it works at least since 2.95.
* Special care must be taken so that it does not need any uninitialized data.
*/
__attribute__((constructor))
static void _do_register(void)
{
struct poller *p;
if (nbpollers >= MAX_POLLERS)
return;
p = &pollers[nbpollers++];
p->name = "poll";
p->pref = 200;
p->flags = HAP_POLL_F_ERRHUP;
p->private = NULL;
p->clo = __fd_clo;
p->test = _do_test;
p->init = _do_init;
p->term = _do_term;
p->poll = _do_poll;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/