git daemon: avoid waking up too often

To avoid waking up unnecessarily, a pipe is set up that is only ever
written to by child_handler(), when a child disconnects, as suggested
per Junio.

This avoids waking up the main process every second to see if a child
was disconnected.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Johannes Schindelin 2008-07-22 23:03:01 +01:00 committed by Junio C Hamano
parent 3b6aeb3cc3
commit f9bbefc701

View file

@ -16,6 +16,7 @@
static int log_syslog;
static int verbose;
static int reuseaddr;
static int child_handler_pipe[2];
static const char daemon_usage[] =
"git daemon [--verbose] [--syslog] [--export-all]\n"
@ -788,6 +789,7 @@ static void child_handler(int signo)
pid = -pid;
dead_child[reaped % MAX_CHILDREN] = pid;
children_reaped = reaped + 1;
write(child_handler_pipe[1], &status, 1);
continue;
}
break;
@ -933,29 +935,24 @@ static int service_loop(int socknum, int *socklist)
struct pollfd *pfd;
int i;
pfd = xcalloc(socknum, sizeof(struct pollfd));
if (pipe(child_handler_pipe) < 0)
die ("Could not set up pipe for child handler");
pfd = xcalloc(socknum + 1, sizeof(struct pollfd));
for (i = 0; i < socknum; i++) {
pfd[i].fd = socklist[i];
pfd[i].events = POLLIN;
}
pfd[socknum].fd = child_handler_pipe[0];
pfd[socknum].events = POLLIN;
signal(SIGCHLD, child_handler);
for (;;) {
int i;
int timeout;
/*
* This 1-sec timeout could lead to idly looping but it is
* here so that children culled in child_handler() are reported
* without too much delay. We could probably set up a pipe
* to ourselves that we poll, and write to the fd from child_handler()
* to wake us up (and consume it when the poll() returns...
*/
timeout = (children_spawned != children_deleted) ? 1000 : -1;
i = poll(pfd, socknum, timeout);
if (i < 0) {
if (poll(pfd, socknum + 1, -1) < 0) {
if (errno != EINTR) {
error("poll failed, resuming: %s",
strerror(errno));
@ -963,9 +960,9 @@ static int service_loop(int socknum, int *socklist)
}
continue;
}
if (i == 0) {
if (pfd[socknum].revents & POLLIN) {
read(child_handler_pipe[0], &i, 1);
check_dead_children();
continue;
}
for (i = 0; i < socknum; i++) {