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/*
* FD polling functions for Linux epoll
*
* 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 <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>
/* private data */
static THREAD_LOCAL struct epoll_event *epoll_events = NULL;
static int epoll_fd[MAX_THREADS]; // per-thread epoll_fd
/* This structure may be used for any purpose. Warning! do not use it in
* recursive functions !
*/
static THREAD_LOCAL struct epoll_event ev;
#ifndef EPOLLRDHUP
/* EPOLLRDHUP was defined late in libc, and it appeared in kernel 2.6.17 */
#define EPOLLRDHUP 0x2000
#endif
/*
* Immediately remove file descriptor from epoll set upon close.
* Since we forked, some fds share inodes with the other process, and epoll may
* send us events even though this process closed the fd (see man 7 epoll,
* "Questions and answers", Q 6).
*/
REGPRM1 static void __fd_clo(int fd)
{
if (unlikely(fdtab[fd].cloned)) {
unsigned long m = fdtab[fd].thread_mask;
int i;
for (i = global.nbthread - 1; i >= 0; i--)
if (m & (1UL << i))
epoll_ctl(epoll_fd[i], EPOLL_CTL_DEL, fd, &ev);
}
}
/*
* Linux 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 polling changes */
for (updt_idx = 0; updt_idx < fd_nbupdt; updt_idx++) {
fd = fd_updt[updt_idx];
if (!fdtab[fd].owner) {
activity[tid].poll_drop++;
continue;
}
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fdtab[fd].update_mask &= ~tid_bit;
fdtab[fd].new = 0;
eo = fdtab[fd].state;
en = fd_compute_new_polled_status(eo);
fdtab[fd].state = en;
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
if (fdtab[fd].polled_mask & tid_bit) {
if (!(fdtab[fd].thread_mask & tid_bit) || !(en & FD_EV_POLLED_RW)) {
/* fd removed from poll list */
opcode = EPOLL_CTL_DEL;
HA_ATOMIC_AND(&fdtab[fd].polled_mask, ~tid_bit);
}
else {
/* fd status changed */
opcode = EPOLL_CTL_MOD;
}
}
else if ((fdtab[fd].thread_mask & tid_bit) && (en & FD_EV_POLLED_RW)) {
/* new fd in the poll list */
opcode = EPOLL_CTL_ADD;
HA_ATOMIC_OR(&fdtab[fd].polled_mask, tid_bit);
}
else {
continue;
}
/* 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[tid], opcode, fd, &ev);
}
fd_nbupdt = 0;
/* compute the epoll_wait() timeout */
if (!exp)
wait_time = MAX_DELAY_MS;
else if (tick_is_expired(exp, now_ms)) {
activity[tid].poll_exp++;
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[tid], 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) {
activity[tid].poll_dead++;
continue;
}
if (!(fdtab[fd].thread_mask & tid_bit)) {
/* FD has been migrated */
activity[tid].poll_skip++;
epoll_ctl(epoll_fd[tid], EPOLL_CTL_DEL, fd, &ev);
HA_ATOMIC_AND(&fdtab[fd].polled_mask, ~tid_bit);
continue;
}
/* it looks complicated but gcc can optimize it away when constants
* have same values... In fact it depends on gcc :-(
*/
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) {
HA_ATOMIC_OR(&cur_poller.flags, HAP_POLL_F_RDHUP);
n |= FD_POLL_HUP;
}
fd_update_events(fd, n);
}
/* the caller will take care of cached events */
}
static int init_epoll_per_thread()
{
int fd;
epoll_events = calloc(1, sizeof(struct epoll_event) * global.tune.maxpollevents);
if (epoll_events == NULL)
goto fail_alloc;
if (tid) {
epoll_fd[tid] = epoll_create(global.maxsock + 1);
if (epoll_fd[tid] < 0)
goto fail_fd;
}
/* we may have to unregister some events initially registered on the
* original fd when it was alone, and/or to register events on the new
* fd for this thread. Let's just mark them as updated, the poller will
* do the rest.
*/
for (fd = 0; fd < maxfd; fd++)
updt_fd_polling(fd);
return 1;
fail_fd:
free(epoll_events);
fail_alloc:
return 0;
}
static void deinit_epoll_per_thread()
{
if (tid)
close(epoll_fd[tid]);
free(epoll_events);
epoll_events = NULL;
}
/*
* 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)
{
p->private = NULL;
epoll_fd[tid] = epoll_create(global.maxsock + 1);
if (epoll_fd[tid] < 0)
goto fail_fd;
hap_register_per_thread_init(init_epoll_per_thread);
hap_register_per_thread_deinit(deinit_epoll_per_thread);
return 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)
{
if (epoll_fd[tid] >= 0) {
close(epoll_fd[tid]);
epoll_fd[tid] = -1;
}
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[tid] >= 0)
close(epoll_fd[tid]);
epoll_fd[tid] = epoll_create(global.maxsock + 1);
if (epoll_fd[tid] < 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;
int i;
if (nbpollers >= MAX_POLLERS)
return;
for (i = 0; i < MAX_THREADS; i++)
epoll_fd[i] = -1;
p = &pollers[nbpollers++];
p->name = "epoll";
p->pref = 300;
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;
p->fork = _do_fork;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/