diff options
author | Sean Bright <sean.bright@gmail.com> | 2017-04-17 20:06:10 -0400 |
---|---|---|
committer | Sean Bright <sean.bright@gmail.com> | 2017-04-24 12:46:27 -0400 |
commit | cea3742c549a3c31621d2d29a1b78b42211e01d0 (patch) | |
tree | 10d3b39a433741922041fdbe0608d22e1905f1f9 /main | |
parent | dac4442cdd787b58035fcd13d51abbf50a4d7cb3 (diff) |
core: Use eventfd for alert pipes on Linux when possible
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: Iff0fb1573e7f7a187d5211ddc60aa8f3da3edb1d
Diffstat (limited to 'main')
-rw-r--r-- | main/alertpipe.c | 166 | ||||
-rw-r--r-- | main/bridge_channel.c | 87 | ||||
-rw-r--r-- | main/channel_internal_api.c | 121 | ||||
-rw-r--r-- | main/utils.c | 3 |
4 files changed, 186 insertions, 191 deletions
diff --git a/main/alertpipe.c b/main/alertpipe.c new file mode 100644 index 000000000..fa6ec7bcc --- /dev/null +++ b/main/alertpipe.c @@ -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; +} diff --git a/main/bridge_channel.c b/main/bridge_channel.c index 652d40ca4..b466b3c6a 100644 --- a/main/bridge_channel.c +++ b/main/bridge_channel.c @@ -37,6 +37,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #include <signal.h> #include "asterisk/heap.h" +#include "asterisk/alertpipe.h" #include "asterisk/astobj2.h" #include "asterisk/stringfields.h" #include "asterisk/app.h" @@ -956,7 +957,6 @@ static void bridge_frame_free(struct ast_frame *frame) int ast_bridge_channel_queue_frame(struct ast_bridge_channel *bridge_channel, struct ast_frame *fr) { struct ast_frame *dup; - char nudge = 0; if (bridge_channel->suspended /* Also defer DTMF frames. */ @@ -985,7 +985,7 @@ int ast_bridge_channel_queue_frame(struct ast_bridge_channel *bridge_channel, st } AST_LIST_INSERT_TAIL(&bridge_channel->wr_queue, dup, frame_list); - if (write(bridge_channel->alert_pipe[1], &nudge, sizeof(nudge)) != sizeof(nudge)) { + if (ast_alertpipe_write(bridge_channel->alert_pipe)) { ast_log(LOG_ERROR, "We couldn't write alert pipe for %p(%s)... something is VERY wrong\n", bridge_channel, ast_channel_name(bridge_channel->chan)); } @@ -2259,25 +2259,6 @@ static void bridge_channel_handle_control(struct ast_bridge_channel *bridge_chan /*! * \internal - * \param bridge_channel Channel to read wr_queue alert pipe. - * - * \return Nothing - */ -static void bridge_channel_read_wr_queue_alert(struct ast_bridge_channel *bridge_channel) -{ - char nudge; - - if (read(bridge_channel->alert_pipe[0], &nudge, sizeof(nudge)) < 0) { - if (errno != EINTR && errno != EAGAIN) { - ast_log(LOG_WARNING, "read() failed for alert pipe on %p(%s): %s\n", - bridge_channel, ast_channel_name(bridge_channel->chan), - strerror(errno)); - } - } -} - -/*! - * \internal * \brief Handle bridge channel write frame to channel. * \since 12.0.0 * @@ -2298,7 +2279,7 @@ static void bridge_channel_handle_write(struct ast_bridge_channel *bridge_channe /* No frame, flush the alert pipe of excess alerts. */ ast_log(LOG_WARNING, "Weird. No frame from bridge for %s to process?\n", ast_channel_name(bridge_channel->chan)); - bridge_channel_read_wr_queue_alert(bridge_channel); + ast_alertpipe_read(bridge_channel->alert_pipe); ast_bridge_channel_unlock(bridge_channel); return; } @@ -2314,7 +2295,7 @@ static void bridge_channel_handle_write(struct ast_bridge_channel *bridge_channe break; } } - bridge_channel_read_wr_queue_alert(bridge_channel); + ast_alertpipe_read(bridge_channel->alert_pipe); AST_LIST_REMOVE_CURRENT(frame_list); break; } @@ -2852,62 +2833,6 @@ int bridge_channel_internal_allows_optimization(struct ast_bridge_channel *bridg && AST_LIST_EMPTY(&bridge_channel->wr_queue); } -/*! - * \internal - * \brief Close a pipe. - * \since 12.0.0 - * - * \param my_pipe What to close. - * - * \return Nothing - */ -static void pipe_close(int *my_pipe) -{ - if (my_pipe[0] > -1) { - close(my_pipe[0]); - my_pipe[0] = -1; - } - if (my_pipe[1] > -1) { - close(my_pipe[1]); - my_pipe[1] = -1; - } -} - -/*! - * \internal - * \brief Initialize a pipe as non-blocking. - * \since 12.0.0 - * - * \param my_pipe What to initialize. - * - * \retval 0 on success. - * \retval -1 on error. - */ -static int pipe_init_nonblock(int *my_pipe) -{ - int flags; - - my_pipe[0] = -1; - my_pipe[1] = -1; - if (pipe(my_pipe)) { - ast_log(LOG_WARNING, "Can't create pipe! Try increasing max file descriptors with ulimit -n\n"); - return -1; - } - flags = fcntl(my_pipe[0], F_GETFL); - if (fcntl(my_pipe[0], F_SETFL, flags | O_NONBLOCK) < 0) { - ast_log(LOG_WARNING, "Unable to set read pipe nonblocking! (%d: %s)\n", - errno, strerror(errno)); - return -1; - } - flags = fcntl(my_pipe[1], F_GETFL); - if (fcntl(my_pipe[1], F_SETFL, flags | O_NONBLOCK) < 0) { - ast_log(LOG_WARNING, "Unable to set write pipe nonblocking! (%d: %s)\n", - errno, strerror(errno)); - return -1; - } - return 0; -} - /* Destroy elements of the bridge channel structure and the bridge channel structure itself */ static void bridge_channel_destroy(void *obj) { @@ -2927,7 +2852,7 @@ static void bridge_channel_destroy(void *obj) while ((fr = AST_LIST_REMOVE_HEAD(&bridge_channel->wr_queue, frame_list))) { bridge_frame_free(fr); } - pipe_close(bridge_channel->alert_pipe); + ast_alertpipe_close(bridge_channel->alert_pipe); ast_cond_destroy(&bridge_channel->cond); @@ -2944,7 +2869,7 @@ struct ast_bridge_channel *bridge_channel_internal_alloc(struct ast_bridge *brid return NULL; } ast_cond_init(&bridge_channel->cond, NULL); - if (pipe_init_nonblock(bridge_channel->alert_pipe)) { + if (ast_alertpipe_init(bridge_channel->alert_pipe)) { ao2_ref(bridge_channel, -1); return NULL; } diff --git a/main/channel_internal_api.c b/main/channel_internal_api.c index bb33e9f55..d181f52a2 100644 --- a/main/channel_internal_api.c +++ b/main/channel_internal_api.c @@ -38,6 +38,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #include <unistd.h> #include <fcntl.h> +#include "asterisk/alertpipe.h" #include "asterisk/paths.h" #include "asterisk/channel.h" #include "asterisk/channel_internal.h" @@ -1237,152 +1238,52 @@ void ast_channel_named_pickupgroups_set(struct ast_channel *chan, struct ast_nam /* Alertpipe functions */ int ast_channel_alert_write(struct ast_channel *chan) { - char blah = 0x7F; - - if (!ast_channel_alert_writable(chan)) { - errno = EBADF; - return 0; - } - /* preset errno in case returned size does not match */ - errno = EPIPE; - return write(chan->alertpipe[1], &blah, sizeof(blah)) != sizeof(blah); -} - -static int channel_internal_alert_check_nonblock(struct ast_channel *chan) -{ - int flags; - - flags = fcntl(chan->alertpipe[0], F_GETFL); - /* For some odd reason, the alertpipe occasionally loses nonblocking status, - * which immediately causes a deadlock scenario. Detect and prevent this. */ - if ((flags & O_NONBLOCK) == 0) { - ast_log(LOG_ERROR, "Alertpipe on channel %s lost O_NONBLOCK?!!\n", ast_channel_name(chan)); - if (fcntl(chan->alertpipe[0], F_SETFL, flags | O_NONBLOCK) < 0) { - ast_log(LOG_WARNING, "Unable to set alertpipe nonblocking! (%d: %s)\n", errno, strerror(errno)); - return -1; - } - } - return 0; + return ast_alertpipe_write(chan->alertpipe); } ast_alert_status_t ast_channel_internal_alert_flush(struct ast_channel *chan) { - int bytes_read; - char blah[100]; - - if (!ast_channel_internal_alert_readable(chan)) { - return AST_ALERT_NOT_READABLE; - } - if (channel_internal_alert_check_nonblock(chan)) { - return AST_ALERT_READ_FATAL; - } - - /* Read the alertpipe until it is exhausted. */ - for (;;) { - bytes_read = read(chan->alertpipe[0], blah, sizeof(blah)); - 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; + return ast_alertpipe_flush(chan->alertpipe); } ast_alert_status_t ast_channel_internal_alert_read(struct ast_channel *chan) { - char blah; - - if (!ast_channel_internal_alert_readable(chan)) { - return AST_ALERT_NOT_READABLE; - } - if (channel_internal_alert_check_nonblock(chan)) { - return AST_ALERT_READ_FATAL; - } - - if (read(chan->alertpipe[0], &blah, sizeof(blah)) < 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; + return ast_alertpipe_read(chan->alertpipe); } int ast_channel_alert_writable(struct ast_channel *chan) { - return chan->alertpipe[1] > -1; + return ast_alertpipe_writable(chan->alertpipe); } int ast_channel_internal_alert_readable(struct ast_channel *chan) { - return chan->alertpipe[0] > -1; + return ast_alertpipe_readable(chan->alertpipe); } void ast_channel_internal_alertpipe_clear(struct ast_channel *chan) { - chan->alertpipe[0] = chan->alertpipe[1] = -1; + ast_alertpipe_clear(chan->alertpipe); } void ast_channel_internal_alertpipe_close(struct ast_channel *chan) { - if (ast_channel_internal_alert_readable(chan)) { - close(chan->alertpipe[0]); - chan->alertpipe[0] = -1; - } - if (ast_channel_alert_writable(chan)) { - close(chan->alertpipe[1]); - chan->alertpipe[1] = -1; - } + ast_alertpipe_close(chan->alertpipe); } int ast_channel_internal_alertpipe_init(struct ast_channel *chan) { - if (pipe(chan->alertpipe)) { - ast_log(LOG_WARNING, "Channel allocation failed: Can't create alert pipe! Try increasing max file descriptors with ulimit -n\n"); - return -1; - } else { - int flags = fcntl(chan->alertpipe[0], F_GETFL); - if (fcntl(chan->alertpipe[0], F_SETFL, flags | O_NONBLOCK) < 0) { - ast_log(LOG_WARNING, "Channel allocation failed: Unable to set alertpipe nonblocking! (%d: %s)\n", errno, strerror(errno)); - return -1; - } - flags = fcntl(chan->alertpipe[1], F_GETFL); - if (fcntl(chan->alertpipe[1], F_SETFL, flags | O_NONBLOCK) < 0) { - ast_log(LOG_WARNING, "Channel allocation failed: Unable to set alertpipe nonblocking! (%d: %s)\n", errno, strerror(errno)); - return -1; - } - } - return 0; + return ast_alertpipe_init(chan->alertpipe); } int ast_channel_internal_alert_readfd(struct ast_channel *chan) { - return chan->alertpipe[0]; + return ast_alertpipe_readfd(chan->alertpipe); } void ast_channel_internal_alertpipe_swap(struct ast_channel *chan1, struct ast_channel *chan2) { - int i; - for (i = 0; i < ARRAY_LEN(chan1->alertpipe); i++) { - SWAP(chan1->alertpipe[i], chan2->alertpipe[i]); - } + ast_alertpipe_swap(chan1->alertpipe, chan2->alertpipe); } /* file descriptor array accessors */ diff --git a/main/utils.c b/main/utils.c index de7ff8f90..b31db5982 100644 --- a/main/utils.c +++ b/main/utils.c @@ -69,6 +69,9 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #define AST_API_MODULE #include "asterisk/config.h" +#define AST_API_MODULE +#include "asterisk/alertpipe.h" + static char base64[64]; static char b2a[256]; |