From f9bbefc701e319983bb8e13df8d615293c6f386a Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Tue, 22 Jul 2008 23:03:01 +0100 Subject: [PATCH] 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 Signed-off-by: Junio C Hamano --- daemon.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) diff --git a/daemon.c b/daemon.c index 7df41a6a4..4540e8df5 100644 --- a/daemon.c +++ b/daemon.c @@ -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++) { -- 2.30.2