src/ev_epoll.c - haproxy - Gitiles

 /*
  * FD polling functions for Linux epoll
  *
  * Copyright 2000-2012 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 <common/compat.h>
 #include <common/config.h>
 #include <common/debug.h>
 #include <common/epoll.h>
 #include <common/standard.h>
 #include <common/ticks.h>
 #include <common/time.h>
 #include <common/tools.h>

 #include <types/global.h>

 #include <proto/fd.h>
 #include <proto/signal.h>
 #include <proto/task.h>


 static int absmaxevents = 0;    // absolute maximum amounts of polled events

 /* private data */
 static struct epoll_event *epoll_events;
 static int epoll_fd;

 /* This structure may be used for any purpose. Warning! do not use it in
  * recursive functions !
  */
 static struct epoll_event ev;

 #ifndef EPOLLRDHUP
 /* EPOLLRDHUP was defined late in libc, and it appeared in kernel 2.6.17 */
 #define EPOLLRDHUP 0x2000
 #endif

 /*
  * speculative epoll() poller
  */
 REGPRM2 static void _do_poll(struct poller *p, int exp)
 {
 	int status, eo, en;
 	int fd, opcode;
 	int count;
 	int updt_idx;
 	int wait_time;

 	/* first, scan the update list to find changes */
 	for (updt_idx = 0; updt_idx < fd_nbupdt; updt_idx++) {
 		fd = fd_updt[updt_idx];
 		en = fdtab[fd].spec_e & 15;  /* new events */
 		eo = fdtab[fd].spec_e >> 4;  /* previous events */

 		if (fdtab[fd].owner && (eo ^ en)) {
 			if ((eo ^ en) & FD_EV_POLLED_RW) {
 				/* poll status changed */
 				if ((en & FD_EV_POLLED_RW) == 0) {
 					/* fd removed from poll list */
 					opcode = EPOLL_CTL_DEL;
 				}
 				else if ((eo & FD_EV_POLLED_RW) == 0) {
 					/* new fd in the poll list */
 					opcode = EPOLL_CTL_ADD;
 				}
 				else {
 					/* fd status changed */
 					opcode = EPOLL_CTL_MOD;
 				}

 				/* construct the epoll events based on new state */
 				ev.events = 0;
 				if (en & FD_EV_POLLED_R)
 					ev.events |= EPOLLIN | EPOLLRDHUP;

 				if (en & FD_EV_POLLED_W)
 					ev.events |= EPOLLOUT;

 				ev.data.fd = fd;
 				epoll_ctl(epoll_fd, opcode, fd, &ev);
 			}

 			fdtab[fd].spec_e = (en << 4) + en;  /* save new events */

 			if (!(en & FD_EV_ACTIVE_RW)) {
 				/* This fd doesn't use any active entry anymore, we can
 				 * kill its entry.
 				 */
 				release_spec_entry(fd);
 			}
 			else if ((en & ~eo) & FD_EV_ACTIVE_RW) {
 				/* we need a new spec entry now */
 				alloc_spec_entry(fd);
 			}

 		}
 		fdtab[fd].updated = 0;
 		fdtab[fd].new = 0;
 	}
 	fd_nbupdt = 0;

 	/* compute the epoll_wait() timeout */

 	if (fd_nbspec || run_queue || signal_queue_len) {
 		/* Maybe we still have events in the spec list, or there are
 		 * some tasks left pending in the run_queue, so we must not
 		 * wait in epoll() otherwise we would delay their delivery by
 		 * the next timeout.
 		 */
 		wait_time = 0;
 	}
 	else {
 		if (!exp)
 			wait_time = MAX_DELAY_MS;
 		else if (tick_is_expired(exp, now_ms))
 			wait_time = 0;
 		else {
 			wait_time = TICKS_TO_MS(tick_remain(now_ms, exp)) + 1;
 			if (wait_time > MAX_DELAY_MS)
 				wait_time = MAX_DELAY_MS;
 		}
 	}

 	/* now let's wait for polled events */

 	gettimeofday(&before_poll, NULL);
 	status = epoll_wait(epoll_fd, epoll_events, global.tune.maxpollevents, wait_time);
 	tv_update_date(wait_time, status);
 	measure_idle();

 	/* process polled events */

 	for (count = 0; count < status; count++) {
 		unsigned int n;
 		unsigned int e = epoll_events[count].events;
 		fd = epoll_events[count].data.fd;

 		if (!fdtab[fd].owner)
 			continue;

 		/* it looks complicated but gcc can optimize it away when constants
 		 * have same values... In fact it depends on gcc :-(
 		 */
 		fdtab[fd].ev &= FD_POLL_STICKY;
 		if (EPOLLIN == FD_POLL_IN && EPOLLOUT == FD_POLL_OUT &&
 		    EPOLLPRI == FD_POLL_PRI && EPOLLERR == FD_POLL_ERR &&
 		    EPOLLHUP == FD_POLL_HUP) {
 			n = e & (EPOLLIN|EPOLLOUT|EPOLLPRI|EPOLLERR|EPOLLHUP);
 		}
 		else {
 			n =	((e & EPOLLIN ) ? FD_POLL_IN  : 0) |
 				((e & EPOLLPRI) ? FD_POLL_PRI : 0) |
 				((e & EPOLLOUT) ? FD_POLL_OUT : 0) |
 				((e & EPOLLERR) ? FD_POLL_ERR : 0) |
 				((e & EPOLLHUP) ? FD_POLL_HUP : 0);
 		}

 		/* always remap RDHUP to HUP as they're used similarly */
 		if (e & EPOLLRDHUP)
 			n |= FD_POLL_HUP;

 		if (!n)
 			continue;

 		fdtab[fd].ev |= n;

 		if (fdtab[fd].iocb) {
 			int new_updt, old_updt;

 			/* Mark the events as speculative before processing
 			 * them so that if nothing can be done we don't need
 			 * to poll again.
 			 */
 			if (fdtab[fd].ev & FD_POLL_IN)
 				fd_ev_set(fd, DIR_RD);

 			if (fdtab[fd].ev & FD_POLL_OUT)
 				fd_ev_set(fd, DIR_WR);

 			if (fdtab[fd].spec_p) {
 				/* This fd was already scheduled for being called as a speculative I/O */
 				continue;
 			}

 			/* Save number of updates to detect creation of new FDs. */
 			old_updt = fd_nbupdt;
 			fdtab[fd].iocb(fd);

 			/* One or more fd might have been created during the iocb().
 			 * This mainly happens with new incoming connections that have
 			 * just been accepted, so we'd like to process them immediately
 			 * for better efficiency. Second benefit, if at the end the fds
 			 * are disabled again, we can safely destroy their update entry
 			 * to reduce the scope of later scans. This is the reason we
 			 * scan the new entries backwards.
 			 */

 			for (new_updt = fd_nbupdt; new_updt > old_updt; new_updt--) {
 				fd = fd_updt[new_updt - 1];
 				if (!fdtab[fd].new)
 					continue;

 				fdtab[fd].new = 0;
 				fdtab[fd].ev &= FD_POLL_STICKY;

 				if ((fdtab[fd].spec_e & FD_EV_STATUS_R) == FD_EV_ACTIVE_R)
 					fdtab[fd].ev |= FD_POLL_IN;

 				if ((fdtab[fd].spec_e & FD_EV_STATUS_W) == FD_EV_ACTIVE_W)
 					fdtab[fd].ev |= FD_POLL_OUT;

 				if (fdtab[fd].ev && fdtab[fd].iocb && fdtab[fd].owner)
 					fdtab[fd].iocb(fd);

 				/* we can remove this update entry if it's the last one and is
 				 * unused, otherwise we don't touch anything.
 				 */
 				if (new_updt == fd_nbupdt && fdtab[fd].spec_e == 0) {
 					fdtab[fd].updated = 0;
 					fd_nbupdt--;
 				}
 			}
 		}
 	}

 	/* the caller will take care of speculative events */
 }

 /*
  * Initialization of the speculative epoll() 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)
 {
 	p->private = NULL;

 	epoll_fd = epoll_create(global.maxsock + 1);
 	if (epoll_fd < 0)
 		goto fail_fd;

 	/* See comments at the top of the file about this formula. */
 	absmaxevents = MAX(global.tune.maxpollevents, global.maxsock);
 	epoll_events = (struct epoll_event*)
 		calloc(1, sizeof(struct epoll_event) * absmaxevents);

 	if (epoll_events == NULL)
 		goto fail_ee;

 	return 1;

  fail_ee:
 	close(epoll_fd);
 	epoll_fd = -1;
  fail_fd:
 	p->pref = 0;
 	return 0;
 }

 /*
  * Termination of the speculative epoll() poller.
  * Memory is released and the poller is marked as unselectable.
  */
 REGPRM1 static void _do_term(struct poller *p)
 {
 	free(epoll_events);

 	if (epoll_fd >= 0) {
 		close(epoll_fd);
 		epoll_fd = -1;
 	}

 	epoll_events = NULL;
 	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)
 {
 	int fd;

 	fd = epoll_create(global.maxsock + 1);
 	if (fd < 0)
 		return 0;
 	close(fd);
 	return 1;
 }

 /*
  * Recreate the epoll file descriptor after a fork(). Returns 1 if OK,
  * otherwise 0. It will ensure that all processes will not share their
  * epoll_fd. Some side effects were encountered because of this, such
  * as epoll_wait() returning an FD which was previously deleted.
  */
 REGPRM1 static int _do_fork(struct poller *p)
 {
 	if (epoll_fd >= 0)
 		close(epoll_fd);
 	epoll_fd = epoll_create(global.maxsock + 1);
 	if (epoll_fd < 0)
 		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;

 	epoll_fd = -1;
 	p = &pollers[nbpollers++];

 	p->name = "epoll";
 	p->pref = 300;
 	p->private = NULL;

 	p->clo  = NULL;
 	p->test = _do_test;
 	p->init = _do_init;
 	p->term = _do_term;
 	p->poll = _do_poll;
 	p->fork = _do_fork;
 }


 /*
  * Local variables:
  *  c-indent-level: 8
  *  c-basic-offset: 8
  * End:
  */
	/*
	* FD polling functions for Linux epoll
	*
	* Copyright 2000-2012 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 <common/compat.h>
	#include <common/config.h>
	#include <common/debug.h>
	#include <common/epoll.h>
	#include <common/standard.h>
	#include <common/ticks.h>
	#include <common/time.h>
	#include <common/tools.h>

	#include <types/global.h>

	#include <proto/fd.h>
	#include <proto/signal.h>
	#include <proto/task.h>


	static int absmaxevents = 0; // absolute maximum amounts of polled events

	/* private data */
	static struct epoll_event *epoll_events;
	static int epoll_fd;

	/* This structure may be used for any purpose. Warning! do not use it in
	* recursive functions !
	*/
	static struct epoll_event ev;

	#ifndef EPOLLRDHUP
	/* EPOLLRDHUP was defined late in libc, and it appeared in kernel 2.6.17 */
	#define EPOLLRDHUP 0x2000
	#endif

	/*
	* speculative epoll() poller
	*/
	REGPRM2 static void _do_poll(struct poller *p, int exp)
	{
	int status, eo, en;
	int fd, opcode;
	int count;
	int updt_idx;
	int wait_time;

	/* first, scan the update list to find changes */
	for (updt_idx = 0; updt_idx < fd_nbupdt; updt_idx++) {
	fd = fd_updt[updt_idx];
	en = fdtab[fd].spec_e & 15; /* new events */
	eo = fdtab[fd].spec_e >> 4; /* previous events */

	if (fdtab[fd].owner && (eo ^ en)) {
	if ((eo ^ en) & FD_EV_POLLED_RW) {
	/* poll status changed */
	if ((en & FD_EV_POLLED_RW) == 0) {
	/* fd removed from poll list */
	opcode = EPOLL_CTL_DEL;
	}
	else if ((eo & FD_EV_POLLED_RW) == 0) {
	/* new fd in the poll list */
	opcode = EPOLL_CTL_ADD;
	}
	else {
	/* fd status changed */
	opcode = EPOLL_CTL_MOD;
	}

	/* construct the epoll events based on new state */
	ev.events = 0;
	if (en & FD_EV_POLLED_R)
	ev.events \|= EPOLLIN \| EPOLLRDHUP;

	if (en & FD_EV_POLLED_W)
	ev.events \|= EPOLLOUT;

	ev.data.fd = fd;
	epoll_ctl(epoll_fd, opcode, fd, &ev);
	}

	fdtab[fd].spec_e = (en << 4) + en; /* save new events */

	if (!(en & FD_EV_ACTIVE_RW)) {
	/* This fd doesn't use any active entry anymore, we can
	* kill its entry.
	*/
	release_spec_entry(fd);
	}
	else if ((en & ~eo) & FD_EV_ACTIVE_RW) {
	/* we need a new spec entry now */
	alloc_spec_entry(fd);
	}

	}
	fdtab[fd].updated = 0;
	fdtab[fd].new = 0;
	}
	fd_nbupdt = 0;

	/* compute the epoll_wait() timeout */

	if (fd_nbspec \|\| run_queue \|\| signal_queue_len) {
	/* Maybe we still have events in the spec list, or there are
	* some tasks left pending in the run_queue, so we must not
	* wait in epoll() otherwise we would delay their delivery by
	* the next timeout.
	*/
	wait_time = 0;
	}
	else {
	if (!exp)
	wait_time = MAX_DELAY_MS;
	else if (tick_is_expired(exp, now_ms))
	wait_time = 0;
	else {
	wait_time = TICKS_TO_MS(tick_remain(now_ms, exp)) + 1;
	if (wait_time > MAX_DELAY_MS)
	wait_time = MAX_DELAY_MS;
	}
	}

	/* now let's wait for polled events */

	gettimeofday(&before_poll, NULL);
	status = epoll_wait(epoll_fd, epoll_events, global.tune.maxpollevents, wait_time);
	tv_update_date(wait_time, status);
	measure_idle();

	/* process polled events */

	for (count = 0; count < status; count++) {
	unsigned int n;
	unsigned int e = epoll_events[count].events;
	fd = epoll_events[count].data.fd;

	if (!fdtab[fd].owner)
	continue;

	/* it looks complicated but gcc can optimize it away when constants
	* have same values... In fact it depends on gcc :-(
	*/
	fdtab[fd].ev &= FD_POLL_STICKY;
	if (EPOLLIN == FD_POLL_IN && EPOLLOUT == FD_POLL_OUT &&
	EPOLLPRI == FD_POLL_PRI && EPOLLERR == FD_POLL_ERR &&
	EPOLLHUP == FD_POLL_HUP) {
	n = e & (EPOLLIN\|EPOLLOUT\|EPOLLPRI\|EPOLLERR\|EPOLLHUP);
	}
	else {
	n = ((e & EPOLLIN ) ? FD_POLL_IN : 0) \|
	((e & EPOLLPRI) ? FD_POLL_PRI : 0) \|
	((e & EPOLLOUT) ? FD_POLL_OUT : 0) \|
	((e & EPOLLERR) ? FD_POLL_ERR : 0) \|
	((e & EPOLLHUP) ? FD_POLL_HUP : 0);
	}

	/* always remap RDHUP to HUP as they're used similarly */
	if (e & EPOLLRDHUP)
	n \|= FD_POLL_HUP;

	if (!n)
	continue;

	fdtab[fd].ev \|= n;

	if (fdtab[fd].iocb) {
	int new_updt, old_updt;

	/* Mark the events as speculative before processing
	* them so that if nothing can be done we don't need
	* to poll again.
	*/
	if (fdtab[fd].ev & FD_POLL_IN)
	fd_ev_set(fd, DIR_RD);

	if (fdtab[fd].ev & FD_POLL_OUT)
	fd_ev_set(fd, DIR_WR);

	if (fdtab[fd].spec_p) {
	/* This fd was already scheduled for being called as a speculative I/O */
	continue;
	}

	/* Save number of updates to detect creation of new FDs. */
	old_updt = fd_nbupdt;
	fdtab[fd].iocb(fd);

	/* One or more fd might have been created during the iocb().
	* This mainly happens with new incoming connections that have
	* just been accepted, so we'd like to process them immediately
	* for better efficiency. Second benefit, if at the end the fds
	* are disabled again, we can safely destroy their update entry
	* to reduce the scope of later scans. This is the reason we
	* scan the new entries backwards.
	*/

	for (new_updt = fd_nbupdt; new_updt > old_updt; new_updt--) {
	fd = fd_updt[new_updt - 1];
	if (!fdtab[fd].new)
	continue;

	fdtab[fd].new = 0;
	fdtab[fd].ev &= FD_POLL_STICKY;

	if ((fdtab[fd].spec_e & FD_EV_STATUS_R) == FD_EV_ACTIVE_R)
	fdtab[fd].ev \|= FD_POLL_IN;

	if ((fdtab[fd].spec_e & FD_EV_STATUS_W) == FD_EV_ACTIVE_W)
	fdtab[fd].ev \|= FD_POLL_OUT;

	if (fdtab[fd].ev && fdtab[fd].iocb && fdtab[fd].owner)
	fdtab[fd].iocb(fd);

	/* we can remove this update entry if it's the last one and is
	* unused, otherwise we don't touch anything.
	*/
	if (new_updt == fd_nbupdt && fdtab[fd].spec_e == 0) {
	fdtab[fd].updated = 0;
	fd_nbupdt--;
	}
	}
	}
	}

	/* the caller will take care of speculative events */
	}

	/*
	* Initialization of the speculative epoll() 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)
	{
	p->private = NULL;

	epoll_fd = epoll_create(global.maxsock + 1);
	if (epoll_fd < 0)
	goto fail_fd;

	/* See comments at the top of the file about this formula. */
	absmaxevents = MAX(global.tune.maxpollevents, global.maxsock);
	epoll_events = (struct epoll_event*)
	calloc(1, sizeof(struct epoll_event) * absmaxevents);

	if (epoll_events == NULL)
	goto fail_ee;

	return 1;

	fail_ee:
	close(epoll_fd);
	epoll_fd = -1;
	fail_fd:
	p->pref = 0;
	return 0;
	}

	/*
	* Termination of the speculative epoll() poller.
	* Memory is released and the poller is marked as unselectable.
	*/
	REGPRM1 static void _do_term(struct poller *p)
	{
	free(epoll_events);

	if (epoll_fd >= 0) {
	close(epoll_fd);
	epoll_fd = -1;
	}

	epoll_events = NULL;
	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)
	{
	int fd;

	fd = epoll_create(global.maxsock + 1);
	if (fd < 0)
	return 0;
	close(fd);
	return 1;
	}

	/*
	* Recreate the epoll file descriptor after a fork(). Returns 1 if OK,
	* otherwise 0. It will ensure that all processes will not share their
	* epoll_fd. Some side effects were encountered because of this, such
	* as epoll_wait() returning an FD which was previously deleted.
	*/
	REGPRM1 static int _do_fork(struct poller *p)
	{
	if (epoll_fd >= 0)
	close(epoll_fd);
	epoll_fd = epoll_create(global.maxsock + 1);
	if (epoll_fd < 0)
	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;

	epoll_fd = -1;
	p = &pollers[nbpollers++];

	p->name = "epoll";
	p->pref = 300;
	p->private = NULL;

	p->clo = NULL;
	p->test = _do_test;
	p->init = _do_init;
	p->term = _do_term;
	p->poll = _do_poll;
	p->fork = _do_fork;
	}


	/*
	* Local variables:
	* c-indent-level: 8
	* c-basic-offset: 8
	* End:
	*/