sin/samba-mirror
1
0
Fork 0
mirror of https://github.com/samba-team/samba.git synced 2025-01-11 05:18:09 +03:00
Code

tevent: Use eventfd for signal/thread wakeup

Browse Source 
According to the manpage, eventfd is cheaper than a pipe. At least, we can save
a file descriptor and space for it in struct tevent_context :-)

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
This commit is contained in:
Volker Lendecke 2016-08-12 16:32:33 +02:00 committed by Jeremy Allison
parent f40c171743
commit c7e2cb839d
2 changed files with 53 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
lib/tevent/tevent.c
View File

@ -66,6 +66,9 @@
#include "tevent.h"
#include "tevent_internal.h"
#include "tevent_util.h"
#ifdef HAVE_EVENTFD
#include <sys/eventfd.h>
#endif
static void tevent_abort(struct tevent_context *ev, const char *reason);
@ -767,7 +770,7 @@ done:
bool tevent_common_have_events(struct tevent_context *ev)
{
if (ev->fd_events != NULL) {
if (ev->fd_events != ev->pipe_fde) {
if (ev->fd_events != ev->wakeup_fde) {
return true;
}
if (ev->fd_events->next != NULL) {
@ -840,10 +843,14 @@ static void wakeup_pipe_handler(struct tevent_context *ev,
{
ssize_t ret;
/* its non-blocking, doesn't matter if we read too much */
do {
char c[16];
ret = read(fde->fd, c, sizeof(c));
/*
* This is the boilerplate for eventfd, but it works
* for pipes too. And as we don't care about the data
* we read, we're fine.
*/
uint64_t val;
ret = read(fde->fd, &val, sizeof(val));
} while (ret == -1 && errno == EINTR);
}
@ -855,23 +862,39 @@ int tevent_common_wakeup_init(struct tevent_context *ev)
{
int ret;
if (ev->pipe_fde != NULL) {
if (ev->wakeup_fde != NULL) {
return 0;
}
ret = pipe(ev->pipe_fds);
#ifdef HAVE_EVENTFD
ret = eventfd(0, EFD_NONBLOCK);
if (ret == -1) {
return errno;
}
ev_set_blocking(ev->pipe_fds[0], false);
ev_set_blocking(ev->pipe_fds[1], false);
ev->wakeup_fd = ret;
#else
{
int pipe_fds[2];
ret = pipe(pipe_fds);
if (ret == -1) {
return errno;
}
ev->wakeup_fd = pipe_fds[0];
ev->wakeup_write_fd = pipe_fds[1];
ev->pipe_fde = tevent_add_fd(ev, ev, ev->pipe_fds[0],
ev_set_blocking(ev->wakeup_fd, false);
ev_set_blocking(ev->wakeup_write_fd, false);
}
#endif
ev->wakeup_fde = tevent_add_fd(ev, ev, ev->wakeup_fd,
TEVENT_FD_READ,
wakeup_pipe_handler, NULL);
if (ev->pipe_fde == NULL) {
close(ev->pipe_fds[0]);
close(ev->pipe_fds[1]);
if (ev->wakeup_fde == NULL) {
close(ev->wakeup_fd);
#ifndef HAVE_EVENTFD
close(ev->wakeup_write_fd);
#endif
return ENOMEM;
}
@ -882,13 +905,18 @@ int tevent_common_wakeup(struct tevent_context *ev)
{
ssize_t ret;
if (ev->pipe_fds[1] == -1) {
if (ev->wakeup_fde == NULL) {
return ENOTCONN;
}
do {
#ifdef HAVE_EVENTFD
uint64_t val = 1;
ret = write(ev->wakeup_fd, &val, sizeof(val));
#else
char c = '\0';
ret = write(ev->pipe_fds[1], &c, 1);
ret = write(ev->wakeup_write_fd, &c, 1);
#endif
} while ((ret == -1) && (errno == EINTR));
return 0;
@ -896,12 +924,14 @@ int tevent_common_wakeup(struct tevent_context *ev)
static void tevent_common_wakeup_fini(struct tevent_context *ev)
{
if (ev->pipe_fde == NULL) {
if (ev->wakeup_fde == NULL) {
return;
}
TALLOC_FREE(ev->pipe_fde);
TALLOC_FREE(ev->wakeup_fde);
close(ev->pipe_fds[0]);
close(ev->pipe_fds[1]);
close(ev->wakeup_fd);
#ifndef HAVE_EVENTFD
close(ev->wakeup_write_fd);
#endif
}

7
lib/tevent/tevent_internal.h
View File

@ -276,8 +276,11 @@ struct tevent_context {
void *additional_data;
/* pipe hack used with signal handlers */
struct tevent_fd *pipe_fde;
int pipe_fds[2];
struct tevent_fd *wakeup_fde;
int wakeup_fd;
#ifndef HAVE_EVENT_FD
int wakeup_write_fd;
#endif
/* debugging operations */
struct tevent_debug_ops debug_ops;