src/ev_poll.c - haproxy - Gitiles

 /*
  * 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 <common/compat.h>
 #include <common/config.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>


 #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;

 REGPRM1 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
  */
 REGPRM3 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.
  */
 REGPRM1 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:
 	free(poll_events);
 	p->pref = 0;
 	return 0;
 }

 /*
  * Termination of the poll() poller.
  * Memory is released and the poller is marked as unselectable.
  */
 REGPRM1 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.
  */
 REGPRM1 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 = 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:
  */
	/*
	* 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 <common/compat.h>
	#include <common/config.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>


	#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;

	REGPRM1 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
	*/
	REGPRM3 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 * 8sizeof(*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 * 8sizeof(fd_evts); count < 8sizeof(**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.
	*/
	REGPRM1 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:
	free(poll_events);
	p->pref = 0;
	return 0;
	}

	/*
	* Termination of the poll() poller.
	* Memory is released and the poller is marked as unselectable.
	*/
	REGPRM1 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.
	*/
	REGPRM1 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 = 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:
	*/