blob: 9dd93b8873c4763bd873e7af85ed6b14b2e8225d [file] [log] [blame]
/*
* FD polling functions for generic select()
*
* 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.
*
*/
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <haproxy/api.h>
#include <common/hathreads.h>
#include <common/ticks.h>
#include <common/time.h>
#include <types/global.h>
#include <proto/activity.h>
#include <proto/fd.h>
/* private data */
static int maxfd; /* # of the highest fd + 1 */
static unsigned int *fd_evts[2];
static THREAD_LOCAL fd_set *tmp_evts[2];
/* Immediately remove the entry upon close() */
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;
}
}
/*
* Select() poller
*/
static void _do_poll(struct poller *p, int exp, int wake)
{
int status;
int fd, i;
struct timeval delta;
int delta_ms;
int fds;
int updt_idx;
char count;
int readnotnull, writenotnull;
int old_maxfd, new_maxfd, max_add_fd;
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();
fd_nbupdt = 0;
/* let's restore fdset state */
readnotnull = 0; writenotnull = 0;
for (i = 0; i < (maxfd + FD_SETSIZE - 1)/(8*sizeof(int)); i++) {
readnotnull |= (*(((int*)tmp_evts[DIR_RD])+i) = *(((int*)fd_evts[DIR_RD])+i)) != 0;
writenotnull |= (*(((int*)tmp_evts[DIR_WR])+i) = *(((int*)fd_evts[DIR_WR])+i)) != 0;
}
/* now let's wait for events */
delta_ms = wake ? 0 : compute_poll_timeout(exp);
delta.tv_sec = (delta_ms / 1000);
delta.tv_usec = (delta_ms % 1000) * 1000;
tv_entering_poll();
activity_count_runtime();
status = select(maxfd,
readnotnull ? tmp_evts[DIR_RD] : NULL,
writenotnull ? tmp_evts[DIR_WR] : NULL,
NULL,
&delta);
tv_update_date(delta_ms, status);
tv_leaving_poll(delta_ms, status);
thread_harmless_end();
if (sleeping_thread_mask & tid_bit)
_HA_ATOMIC_AND(&sleeping_thread_mask, ~tid_bit);
if (status <= 0)
return;
for (fds = 0; (fds * BITS_PER_INT) < maxfd; fds++) {
if ((((int *)(tmp_evts[DIR_RD]))[fds] | ((int *)(tmp_evts[DIR_WR]))[fds]) == 0)
continue;
for (count = BITS_PER_INT, fd = fds * BITS_PER_INT; count && fd < maxfd; count--, fd++) {
unsigned int n = 0;
if (!fdtab[fd].owner) {
activity[tid].poll_dead++;
continue;
}
if (!(fdtab[fd].thread_mask & tid_bit)) {
activity[tid].poll_skip++;
continue;
}
if (FD_ISSET(fd, tmp_evts[DIR_RD]))
n |= FD_EV_READY_R;
if (FD_ISSET(fd, tmp_evts[DIR_WR]))
n |= FD_EV_READY_W;
fd_update_events(fd, n);
}
}
}
static int init_select_per_thread()
{
int fd_set_bytes;
fd_set_bytes = sizeof(fd_set) * (global.maxsock + FD_SETSIZE - 1) / FD_SETSIZE;
tmp_evts[DIR_RD] = (fd_set *)calloc(1, fd_set_bytes);
if (tmp_evts[DIR_RD] == NULL)
goto fail;
tmp_evts[DIR_WR] = (fd_set *)calloc(1, fd_set_bytes);
if (tmp_evts[DIR_WR] == NULL)
goto fail;
return 1;
fail:
free(tmp_evts[DIR_RD]);
free(tmp_evts[DIR_WR]);
return 0;
}
static void deinit_select_per_thread()
{
free(tmp_evts[DIR_WR]);
tmp_evts[DIR_WR] = NULL;
free(tmp_evts[DIR_RD]);
tmp_evts[DIR_RD] = NULL;
}
/*
* Initialization of the select() 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)
{
int fd_set_bytes;
p->private = NULL;
if (global.maxsock > FD_SETSIZE)
goto fail_srevt;
fd_set_bytes = sizeof(fd_set) * (global.maxsock + FD_SETSIZE - 1) / FD_SETSIZE;
if ((fd_evts[DIR_RD] = calloc(1, fd_set_bytes)) == NULL)
goto fail_srevt;
if ((fd_evts[DIR_WR] = calloc(1, fd_set_bytes)) == NULL)
goto fail_swevt;
hap_register_per_thread_init(init_select_per_thread);
hap_register_per_thread_deinit(deinit_select_per_thread);
return 1;
fail_swevt:
free(fd_evts[DIR_RD]);
fail_srevt:
p->pref = 0;
return 0;
}
/*
* Termination of the select() 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)
{
if (global.maxsock > FD_SETSIZE)
return 0;
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 = "select";
p->pref = 150;
p->flags = 0;
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:
*/