mirror of https://github.com/asterisk/asterisk
The primary win of switching to eventfd when possible is that it only uses a single file descriptor while pipe() will use two. This means for each bridge channel we're reducing the number of required file descriptors by 1, and - if you're using timerfd - we also now have 1 less file descriptor per Asterisk channel. The API is not ideal (passing int arrays), but this is the cleanest approach I could come up with to maintain API/ABI. I've also removed what I believe to be an erroneous code block that checked the non-blocking flag on the pipe ends for each read. If the file descriptor is 'losing' its non-blocking mode, it is because of a bug somewhere else in our code. In my testing I haven't seen any measurable difference in performance. Change-Id: Iff0fb1573e7f7a187d5211ddc60aa8f3da3edb1dcertified/13.18
Sean Bright
8 years ago
parent
dac4442cdd
commit
cea3742c54
@ -0,0 +1,159 @@
|
||||
/*
|
||||
* Asterisk -- An open source telephony toolkit.
|
||||
*
|
||||
* Copyright (C) 2017, Sean Bright
|
||||
*
|
||||
* Sean Bright <sean.bright@gmail.com>
|
||||
*
|
||||
* See http://www.asterisk.org for more information about
|
||||
* the Asterisk project. Please do not directly contact
|
||||
* any of the maintainers of this project for assistance;
|
||||
* the project provides a web site, mailing lists and IRC
|
||||
* channels for your use.
|
||||
*
|
||||
* This program is free software, distributed under the terms of
|
||||
* the GNU General Public License Version 2. See the LICENSE file
|
||||
* at the top of the source tree.
|
||||
*/
|
||||
|
||||
#ifndef ASTERISK_ALERTPIPE_H
|
||||
#define ASTERISK_ALERTPIPE_H
|
||||
|
||||
#include "asterisk/utils.h"
|
||||
|
||||
typedef enum {
|
||||
AST_ALERT_READ_SUCCESS = 0,
|
||||
AST_ALERT_NOT_READABLE,
|
||||
AST_ALERT_READ_FAIL,
|
||||
AST_ALERT_READ_FATAL,
|
||||
} ast_alert_status_t;
|
||||
|
||||
/*!
|
||||
* \brief Initialize an alert pipe
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p a two-element array to hold the alert pipe's file descriptors
|
||||
*
|
||||
* \return non-zero if a failure occurred, zero otherwise.
|
||||
*/
|
||||
int ast_alertpipe_init(int alert_pipe[2]);
|
||||
|
||||
/*!
|
||||
* \brief Close an alert pipe
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p a two-element containing the alert pipe's file descriptors
|
||||
*/
|
||||
void ast_alertpipe_close(int alert_pipe[2]);
|
||||
|
||||
/*!
|
||||
* \brief Read an event from an alert pipe
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p a two-element array containing the alert pipe's file descriptors
|
||||
*
|
||||
* \retval AST_ALERT_READ_SUCCESS on success
|
||||
* \retval AST_ALERT_NOT_READABLE if the alert pipe is not readable
|
||||
* \retval AST_ALERT_READ_FATAL if the alert pipe's file descriptors are in
|
||||
* blocking mode, or a read error occurs.
|
||||
*/
|
||||
ast_alert_status_t ast_alertpipe_read(int alert_pipe[2]);
|
||||
|
||||
/*!
|
||||
* \brief Write an event to an alert pipe
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p a two-element array containing the alert pipe's file descriptors
|
||||
*
|
||||
* \return see write(2)
|
||||
*/
|
||||
ssize_t ast_alertpipe_write(int alert_pipe[2]);
|
||||
|
||||
/*!
|
||||
* \brief Consume all alerts written to the alert pipe
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p a two-element array containing the alert pipe's file descriptors
|
||||
*
|
||||
* \retval AST_ALERT_READ_SUCCESS on success
|
||||
* \retval AST_ALERT_NOT_READABLE if the alert pipe is not readable
|
||||
* \retval AST_ALERT_READ_FATAL if the alert pipe's file descriptors are in
|
||||
* blocking mode, or a read error occurs.
|
||||
*/
|
||||
ast_alert_status_t ast_alertpipe_flush(int alert_pipe[2]);
|
||||
|
||||
/*!
|
||||
* \brief Sets the alert pipe file descriptors to default values
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p a two-element array containing the alert pipe's file descriptors
|
||||
*/
|
||||
AST_INLINE_API(
|
||||
void ast_alertpipe_clear(int alert_pipe[2]),
|
||||
{
|
||||
alert_pipe[0] = alert_pipe[1] = -1;
|
||||
}
|
||||
)
|
||||
|
||||
/*!
|
||||
* \brief Determine if the alert pipe is readable
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p a two-element array containing the alert pipe's file descriptors
|
||||
*
|
||||
* \return non-zero if the alert pipe is readable, zero otherwise.
|
||||
*/
|
||||
AST_INLINE_API(
|
||||
int attribute_pure ast_alertpipe_readable(int alert_pipe[2]),
|
||||
{
|
||||
return alert_pipe[0] > -1;
|
||||
}
|
||||
)
|
||||
|
||||
/*!
|
||||
* \brief Determine if the alert pipe is writable
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p a two-element array containing the alert pipe's file descriptors
|
||||
*
|
||||
* \return non-zero if the alert pipe is writable, zero otherwise.
|
||||
*/
|
||||
AST_INLINE_API(
|
||||
int attribute_pure ast_alertpipe_writable(int alert_pipe[2]),
|
||||
{
|
||||
return alert_pipe[1] > -1;
|
||||
}
|
||||
)
|
||||
|
||||
/*!
|
||||
* \brief Get the alert pipe's read file descriptor
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p a two-element array containing the alert pipe's file descriptors
|
||||
*
|
||||
* \return -1 if the file descriptor is not initialized, a non-negative value
|
||||
* otherwise.
|
||||
*/
|
||||
AST_INLINE_API(
|
||||
int attribute_pure ast_alertpipe_readfd(int alert_pipe[2]),
|
||||
{
|
||||
return alert_pipe[0];
|
||||
}
|
||||
)
|
||||
|
||||
/*!
|
||||
* \brief Swap the file descriptors from two alert pipes
|
||||
* \since 13.16.0
|
||||
*
|
||||
* \param p1 a two-element array containing an alert pipe's file descriptors
|
||||
* \param p2 a two-element array containing an alert pipe's file descriptors
|
||||
*/
|
||||
AST_INLINE_API(
|
||||
void ast_alertpipe_swap(int alert_pipe_1[2], int alert_pipe_2[2]),
|
||||
{
|
||||
SWAP(alert_pipe_1[0], alert_pipe_2[0]);
|
||||
SWAP(alert_pipe_1[1], alert_pipe_2[1]);
|
||||
}
|
||||
)
|
||||
|
||||
#endif /* ASTERISK_ALERTPIPE_H */
|
||||
@ -0,0 +1,166 @@
|
||||
/*
|
||||
* Asterisk -- An open source telephony toolkit.
|
||||
*
|
||||
* Copyright (C) 2017, Sean Bright
|
||||
*
|
||||
* Sean Bright <sean.bright@gmail.com>
|
||||
*
|
||||
* See http://www.asterisk.org for more information about
|
||||
* the Asterisk project. Please do not directly contact
|
||||
* any of the maintainers of this project for assistance;
|
||||
* the project provides a web site, mailing lists and IRC
|
||||
* channels for your use.
|
||||
*
|
||||
* This program is free software, distributed under the terms of
|
||||
* the GNU General Public License Version 2. See the LICENSE file
|
||||
* at the top of the source tree.
|
||||
*/
|
||||
|
||||
/*! \file
|
||||
*
|
||||
* \brief Alert Pipe API
|
||||
*
|
||||
* \author Sean Bright
|
||||
*/
|
||||
|
||||
#include "asterisk.h"
|
||||
|
||||
#include <unistd.h>
|
||||
#include <fcntl.h>
|
||||
|
||||
#ifdef HAVE_EVENTFD
|
||||
# include <sys/eventfd.h>
|
||||
#endif
|
||||
|
||||
#include "asterisk/alertpipe.h"
|
||||
#include "asterisk/logger.h"
|
||||
|
||||
int ast_alertpipe_init(int alert_pipe[2])
|
||||
{
|
||||
#ifdef HAVE_EVENTFD
|
||||
|
||||
int fd = eventfd(0, EFD_NONBLOCK | EFD_SEMAPHORE);
|
||||
if (fd > -1) {
|
||||
alert_pipe[0] = alert_pipe[1] = fd;
|
||||
return 0;
|
||||
}
|
||||
|
||||
ast_log(LOG_WARNING, "Failed to create alert pipe with eventfd(), falling back to pipe(): %s\n",
|
||||
strerror(errno));
|
||||
ast_alertpipe_clear(alert_pipe);
|
||||
|
||||
#endif
|
||||
|
||||
if (pipe(alert_pipe)) {
|
||||
ast_log(LOG_WARNING, "Failed to create alert pipe: %s\n", strerror(errno));
|
||||
return -1;
|
||||
} else {
|
||||
int flags = fcntl(alert_pipe[0], F_GETFL);
|
||||
if (fcntl(alert_pipe[0], F_SETFL, flags | O_NONBLOCK) < 0) {
|
||||
ast_log(LOG_WARNING, "Failed to set non-blocking mode on alert pipe: %s\n",
|
||||
strerror(errno));
|
||||
ast_alertpipe_close(alert_pipe);
|
||||
return -1;
|
||||
}
|
||||
flags = fcntl(alert_pipe[1], F_GETFL);
|
||||
if (fcntl(alert_pipe[1], F_SETFL, flags | O_NONBLOCK) < 0) {
|
||||
ast_log(LOG_WARNING, "Failed to set non-blocking mode on alert pipe: %s\n",
|
||||
strerror(errno));
|
||||
ast_alertpipe_close(alert_pipe);
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
void ast_alertpipe_close(int alert_pipe[2])
|
||||
{
|
||||
#ifdef HAVE_EVENTFD
|
||||
|
||||
if (alert_pipe[0] == alert_pipe[1]) {
|
||||
if (alert_pipe[0] > -1) {
|
||||
close(alert_pipe[0]);
|
||||
ast_alertpipe_clear(alert_pipe);
|
||||
}
|
||||
return;
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
if (alert_pipe[0] > -1) {
|
||||
close(alert_pipe[0]);
|
||||
}
|
||||
if (alert_pipe[1] > -1) {
|
||||
close(alert_pipe[1]);
|
||||
}
|
||||
ast_alertpipe_clear(alert_pipe);
|
||||
}
|
||||
|
||||
ast_alert_status_t ast_alertpipe_read(int alert_pipe[2])
|
||||
{
|
||||
uint64_t tmp;
|
||||
|
||||
if (!ast_alertpipe_readable(alert_pipe)) {
|
||||
return AST_ALERT_NOT_READABLE;
|
||||
}
|
||||
|
||||
if (read(alert_pipe[0], &tmp, sizeof(tmp)) < 0) {
|
||||
if (errno != EINTR && errno != EAGAIN) {
|
||||
ast_log(LOG_WARNING, "read() failed: %s\n", strerror(errno));
|
||||
return AST_ALERT_READ_FAIL;
|
||||
}
|
||||
}
|
||||
|
||||
return AST_ALERT_READ_SUCCESS;
|
||||
}
|
||||
|
||||
ssize_t ast_alertpipe_write(int alert_pipe[2])
|
||||
{
|
||||
uint64_t tmp = 1;
|
||||
|
||||
if (!ast_alertpipe_writable(alert_pipe)) {
|
||||
errno = EBADF;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* preset errno in case returned size does not match */
|
||||
errno = EPIPE;
|
||||
return write(alert_pipe[1], &tmp, sizeof(tmp)) != sizeof(tmp);
|
||||
}
|
||||
|
||||
ast_alert_status_t ast_alertpipe_flush(int alert_pipe[2])
|
||||
{
|
||||
int bytes_read;
|
||||
uint64_t tmp[16];
|
||||
|
||||
if (!ast_alertpipe_readable(alert_pipe)) {
|
||||
return AST_ALERT_NOT_READABLE;
|
||||
}
|
||||
|
||||
/* Read the alertpipe until it is exhausted. */
|
||||
for (;;) {
|
||||
bytes_read = read(alert_pipe[0], tmp, sizeof(tmp));
|
||||
if (bytes_read < 0) {
|
||||
if (errno == EINTR) {
|
||||
continue;
|
||||
}
|
||||
if (errno == EAGAIN || errno == EWOULDBLOCK) {
|
||||
/*
|
||||
* Would block so nothing left to read.
|
||||
* This is the normal loop exit.
|
||||
*/
|
||||
break;
|
||||
}
|
||||
ast_log(LOG_WARNING, "read() failed flushing alertpipe: %s\n",
|
||||
strerror(errno));
|
||||
return AST_ALERT_READ_FAIL;
|
||||
}
|
||||
if (!bytes_read) {
|
||||
/* Read nothing so we are done */
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
return AST_ALERT_READ_SUCCESS;
|
||||
}
|
||||
Loading…
Reference in new issue