src/ev_epoll.c - haproxy - Gitiles

 /*
  * FD polling functions for linux epoll()
  *
  * Copyright 2000-2011 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/epoll.h>
 #include <common/standard.h>
 #include <common/ticks.h>
 #include <common/time.h>
 #include <common/tools.h>

 #include <types/fd.h>
 #include <types/global.h>

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

 /* This is what we store in a list. It consists in old values and fds to detect changes. */
 struct fd_chg {
 	unsigned int prev:2;	// previous state mask. New one is in fd_evts.
 	unsigned int fd:30;	// file descriptor
 };

 static int nbchanges = 0;		// number of changes pending
 static struct fd_chg *chg_list = NULL;	// list of changes
 static struct fd_chg **chg_ptr = NULL;	// per-fd changes

 /* Each 32-bit word contains 2-bit descriptors of the latest state for 16 FDs :
  *   desc = (u32 >> (2*fd)) & 3
  *   desc = 0 : FD not set
  *          1 : WRITE not set, READ set
  *          2 : WRITE set, READ not set
  *          3 : WRITE set, READ set
  */

 static uint32_t *fd_evts;

 /* 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;

 /* converts a direction to a single bitmask.
  *  0 => 1
  *  1 => 2
  */
 #define DIR2MSK(dir) ((dir) + 1)

 /* converts an FD to an fd_evts offset and to a bit shift */
 #define FD2OFS(fd)   ((uint32_t)(fd) >> 4)
 #define FD2BIT(fd)   (((uint32_t)(fd) & 0xF) << 1)
 #define FD2MSK(fd)   (3 << FD2BIT(fd))

 /*
  * Returns non-zero if direction <dir> is already set for <fd>.
  */
 REGPRM2 static int __fd_is_set(const int fd, int dir)
 {
 	return (fd_evts[FD2OFS(fd)] >> FD2BIT(fd)) & DIR2MSK(dir);
 }

 /*
  * Adds, mods or deletes <fd> according to current status and to new desired
  * mask <dmask> :
  *
  *    0 = nothing
  *    1 = EPOLLIN
  *    2 = EPOLLOUT
  *    3 = EPOLLIN | EPOLLOUT
  *
  */
 static int dmsk2event[4] = { 0, EPOLLIN, EPOLLOUT, EPOLLIN | EPOLLOUT };


 REGPRM2 static void fd_flush_changes()
 {
 	uint32_t ofs;
 	int opcode;
 	int prev, next;
 	int chg, fd;

 	for (chg = 0; chg < nbchanges; chg++) {
 		prev = chg_list[chg].prev;
 		fd = chg_list[chg].fd;
 		chg_ptr[fd] = NULL;

 		ofs = FD2OFS(fd);
 		next = (fd_evts[ofs] >> FD2BIT(fd)) & 3;

 		if (prev == next)
 			/* if the value was unchanged, do nothing */
 			continue;

 		ev.events = dmsk2event[next];
 		ev.data.fd = fd;

 		if (prev) {
 			if (!next) {
 				/* we want to delete it now */
 				opcode = EPOLL_CTL_DEL;
 			} else {
 				/* we want to switch it */
 				opcode = EPOLL_CTL_MOD;
 			}
 		} else {
 			/* the FD did not exist, let's add it */
 			opcode = EPOLL_CTL_ADD;
 		}

 		epoll_ctl(epoll_fd, opcode, fd, &ev);
 	}
 	nbchanges = 0;
 }

 REGPRM2 static void alloc_chg_list(const int fd, int old_evt)
 {
 	struct fd_chg *ptr;

 	if (unlikely(chg_ptr[fd] != NULL))
 		return;

 #if LIMIT_NUMBER_OF_CHANGES
 	if (nbchanges > 2)
 		fd_flush_changes();
 #endif

 	ptr = &chg_list[nbchanges++];
 	chg_ptr[fd] = ptr;
 	ptr->fd = fd;
 	ptr->prev = old_evt;
 }

 REGPRM2 static void __fd_set(const int fd, int dir)
 {
 	uint32_t ofs = FD2OFS(fd);
 	uint32_t dmsk = DIR2MSK(dir);
 	uint32_t old_evt;

 	old_evt = fd_evts[ofs] >> FD2BIT(fd);
 	old_evt &= 3;
 	if (unlikely(old_evt & dmsk))
 		return;

 	alloc_chg_list(fd, old_evt);
 	dmsk <<= FD2BIT(fd);
 	fd_evts[ofs] |= dmsk;
 }

 REGPRM2 static void __fd_clr(const int fd, int dir)
 {
 	uint32_t ofs = FD2OFS(fd);
 	uint32_t dmsk = DIR2MSK(dir);
 	uint32_t old_evt;

 	old_evt = fd_evts[ofs] >> FD2BIT(fd);
 	old_evt &= 3;
 	if (unlikely(!(old_evt & dmsk)))
 		return;

 	alloc_chg_list(fd, old_evt);
 	dmsk <<= FD2BIT(fd);
 	fd_evts[ofs] &= ~dmsk;
 }

 REGPRM1 static void __fd_rem(int fd)
 {
 	uint32_t ofs = FD2OFS(fd);
 	uint32_t old_evt;

 	old_evt = fd_evts[ofs] >> FD2BIT(fd);
 	old_evt &= 3;

 	if (unlikely(!old_evt))
 		return;

 	alloc_chg_list(fd, old_evt);
 	fd_evts[ofs] &= ~FD2MSK(fd);
 }

 /*
  * On valid epoll() implementations, a call to close() automatically removes
  * the fds. This means that the FD will appear as previously unset.
  */
 REGPRM1 static void __fd_clo(int fd)
 {
 	struct fd_chg *ptr;
 	fd_evts[FD2OFS(fd)] &= ~FD2MSK(fd);
 	ptr = chg_ptr[fd];
 	if (ptr) {
 		ptr->prev = 0;
 		chg_ptr[fd] = NULL;
 	}
 }

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

 	if (likely(nbchanges))
 		fd_flush_changes();

 	/* now let's wait for events */
 	if (run_queue || signal_queue_len)
 		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;
 	}

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

 	for (count = 0; count < status; count++) {
 		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.
 		 */
 		fdtab[fd].ev &= FD_POLL_STICKY;
 		fdtab[fd].ev |=
 			((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);

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

 /*
  * Initialization of the 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)
 {
 	__label__ fail_chg_ptr, fail_chg_list, fail_fdevt, fail_ee, fail_fd;
 	int fd_set_bytes;

 	p->private = NULL;
 	fd_set_bytes = 4 * (global.maxsock + 15) / 16;

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

 	epoll_events = (struct epoll_event*)
 		calloc(1, sizeof(struct epoll_event) * global.tune.maxpollevents);

 	if (epoll_events == NULL)
 		goto fail_ee;

 	if ((fd_evts = (uint32_t *)calloc(1, fd_set_bytes)) == NULL)
 		goto fail_fdevt;

 	chg_list = (struct fd_chg *)calloc(1, sizeof(struct fd_chg) * global.maxsock);
 	if (chg_list == NULL)
 		goto fail_chg_list;

 	chg_ptr = (struct fd_chg **)calloc(1, sizeof(struct fd_chg*) * global.maxsock);
 	if (chg_ptr == NULL)
 		goto fail_chg_ptr;

 	return 1;

  fail_chg_ptr:
 	free(chg_list);
  fail_chg_list:
 	free(fd_evts);
  fail_fdevt:
 	free(epoll_events);
  fail_ee:
 	close(epoll_fd);
 	epoll_fd = -1;
  fail_fd:
 	p->pref = 0;
 	return 0;
 }

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

 	free(chg_ptr);
 	free(chg_list);
 	free(fd_evts);
 	free(epoll_events);

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

 	chg_ptr = NULL;
 	chg_list = NULL;
 	fd_evts = NULL;
 	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->test = _do_test;
 	p->init = _do_init;
 	p->term = _do_term;
 	p->poll = _do_poll;
 	p->fork = _do_fork;

 	p->is_set  = __fd_is_set;
 	p->set = __fd_set;
 	p->wai = __fd_set;
 	p->clr = __fd_clr;
 	p->rem = __fd_rem;
 	p->clo = __fd_clo;
 }


 /*
  * Local variables:
  *  c-indent-level: 8
  *  c-basic-offset: 8
  * End:
  */
	/*
	* FD polling functions for linux epoll()
	*
	* Copyright 2000-2011 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/epoll.h>
	#include <common/standard.h>
	#include <common/ticks.h>
	#include <common/time.h>
	#include <common/tools.h>

	#include <types/fd.h>
	#include <types/global.h>

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

	/* This is what we store in a list. It consists in old values and fds to detect changes. */
	struct fd_chg {
	unsigned int prev:2; // previous state mask. New one is in fd_evts.
	unsigned int fd:30; // file descriptor
	};

	static int nbchanges = 0; // number of changes pending
	static struct fd_chg *chg_list = NULL; // list of changes
	static struct fd_chg **chg_ptr = NULL; // per-fd changes

	/* Each 32-bit word contains 2-bit descriptors of the latest state for 16 FDs :
	* desc = (u32 >> (2*fd)) & 3
	* desc = 0 : FD not set
	* 1 : WRITE not set, READ set
	* 2 : WRITE set, READ not set
	* 3 : WRITE set, READ set
	*/

	static uint32_t *fd_evts;

	/* 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;

	/* converts a direction to a single bitmask.
	* 0 => 1
	* 1 => 2
	*/
	#define DIR2MSK(dir) ((dir) + 1)

	/* converts an FD to an fd_evts offset and to a bit shift */
	#define FD2OFS(fd) ((uint32_t)(fd) >> 4)
	#define FD2BIT(fd) (((uint32_t)(fd) & 0xF) << 1)
	#define FD2MSK(fd) (3 << FD2BIT(fd))

	/*
	* Returns non-zero if direction <dir> is already set for <fd>.
	*/
	REGPRM2 static int __fd_is_set(const int fd, int dir)
	{
	return (fd_evts[FD2OFS(fd)] >> FD2BIT(fd)) & DIR2MSK(dir);
	}

	/*
	* Adds, mods or deletes <fd> according to current status and to new desired
	* mask <dmask> :
	*
	* 0 = nothing
	* 1 = EPOLLIN
	* 2 = EPOLLOUT
	* 3 = EPOLLIN \| EPOLLOUT
	*
	*/
	static int dmsk2event[4] = { 0, EPOLLIN, EPOLLOUT, EPOLLIN \| EPOLLOUT };


	REGPRM2 static void fd_flush_changes()
	{
	uint32_t ofs;
	int opcode;
	int prev, next;
	int chg, fd;

	for (chg = 0; chg < nbchanges; chg++) {
	prev = chg_list[chg].prev;
	fd = chg_list[chg].fd;
	chg_ptr[fd] = NULL;

	ofs = FD2OFS(fd);
	next = (fd_evts[ofs] >> FD2BIT(fd)) & 3;

	if (prev == next)
	/* if the value was unchanged, do nothing */
	continue;

	ev.events = dmsk2event[next];
	ev.data.fd = fd;

	if (prev) {
	if (!next) {
	/* we want to delete it now */
	opcode = EPOLL_CTL_DEL;
	} else {
	/* we want to switch it */
	opcode = EPOLL_CTL_MOD;
	}
	} else {
	/* the FD did not exist, let's add it */
	opcode = EPOLL_CTL_ADD;
	}

	epoll_ctl(epoll_fd, opcode, fd, &ev);
	}
	nbchanges = 0;
	}

	REGPRM2 static void alloc_chg_list(const int fd, int old_evt)
	{
	struct fd_chg *ptr;

	if (unlikely(chg_ptr[fd] != NULL))
	return;

	#if LIMIT_NUMBER_OF_CHANGES
	if (nbchanges > 2)
	fd_flush_changes();
	#endif

	ptr = &chg_list[nbchanges++];
	chg_ptr[fd] = ptr;
	ptr->fd = fd;
	ptr->prev = old_evt;
	}

	REGPRM2 static void __fd_set(const int fd, int dir)
	{
	uint32_t ofs = FD2OFS(fd);
	uint32_t dmsk = DIR2MSK(dir);
	uint32_t old_evt;

	old_evt = fd_evts[ofs] >> FD2BIT(fd);
	old_evt &= 3;
	if (unlikely(old_evt & dmsk))
	return;

	alloc_chg_list(fd, old_evt);
	dmsk <<= FD2BIT(fd);
	fd_evts[ofs] \|= dmsk;
	}

	REGPRM2 static void __fd_clr(const int fd, int dir)
	{
	uint32_t ofs = FD2OFS(fd);
	uint32_t dmsk = DIR2MSK(dir);
	uint32_t old_evt;

	old_evt = fd_evts[ofs] >> FD2BIT(fd);
	old_evt &= 3;
	if (unlikely(!(old_evt & dmsk)))
	return;

	alloc_chg_list(fd, old_evt);
	dmsk <<= FD2BIT(fd);
	fd_evts[ofs] &= ~dmsk;
	}

	REGPRM1 static void __fd_rem(int fd)
	{
	uint32_t ofs = FD2OFS(fd);
	uint32_t old_evt;

	old_evt = fd_evts[ofs] >> FD2BIT(fd);
	old_evt &= 3;

	if (unlikely(!old_evt))
	return;

	alloc_chg_list(fd, old_evt);
	fd_evts[ofs] &= ~FD2MSK(fd);
	}

	/*
	* On valid epoll() implementations, a call to close() automatically removes
	* the fds. This means that the FD will appear as previously unset.
	*/
	REGPRM1 static void __fd_clo(int fd)
	{
	struct fd_chg *ptr;
	fd_evts[FD2OFS(fd)] &= ~FD2MSK(fd);
	ptr = chg_ptr[fd];
	if (ptr) {
	ptr->prev = 0;
	chg_ptr[fd] = NULL;
	}
	}

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

	if (likely(nbchanges))
	fd_flush_changes();

	/* now let's wait for events */
	if (run_queue \|\| signal_queue_len)
	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;
	}

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

	for (count = 0; count < status; count++) {
	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.
	*/
	fdtab[fd].ev &= FD_POLL_STICKY;
	fdtab[fd].ev \|=
	((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);

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

	/*
	* Initialization of the 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)
	{
	__label__ fail_chg_ptr, fail_chg_list, fail_fdevt, fail_ee, fail_fd;
	int fd_set_bytes;

	p->private = NULL;
	fd_set_bytes = 4 * (global.maxsock + 15) / 16;

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

	epoll_events = (struct epoll_event*)
	calloc(1, sizeof(struct epoll_event) * global.tune.maxpollevents);

	if (epoll_events == NULL)
	goto fail_ee;

	if ((fd_evts = (uint32_t *)calloc(1, fd_set_bytes)) == NULL)
	goto fail_fdevt;

	chg_list = (struct fd_chg )calloc(1, sizeof(struct fd_chg) global.maxsock);
	if (chg_list == NULL)
	goto fail_chg_list;

	chg_ptr = (struct fd_chg *)calloc(1, sizeof(struct fd_chg) * global.maxsock);
	if (chg_ptr == NULL)
	goto fail_chg_ptr;

	return 1;

	fail_chg_ptr:
	free(chg_list);
	fail_chg_list:
	free(fd_evts);
	fail_fdevt:
	free(epoll_events);
	fail_ee:
	close(epoll_fd);
	epoll_fd = -1;
	fail_fd:
	p->pref = 0;
	return 0;
	}

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

	free(chg_ptr);
	free(chg_list);
	free(fd_evts);
	free(epoll_events);

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

	chg_ptr = NULL;
	chg_list = NULL;
	fd_evts = NULL;
	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->test = _do_test;
	p->init = _do_init;
	p->term = _do_term;
	p->poll = _do_poll;
	p->fork = _do_fork;

	p->is_set = __fd_is_set;
	p->set = __fd_set;
	p->wai = __fd_set;
	p->clr = __fd_clr;
	p->rem = __fd_rem;
	p->clo = __fd_clo;
	}


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