blob: 90769c1ca8610d4f635aca387b475109d3f17979 [file] [log] [blame]
/*
* 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:
*/