udevd: remove max_childs_running logic

This was needed in the old days, where all the hotplug scripts did
nothing better than sleep for seconds to work around timing issues.
It made sure, that w continued to fork processes, while the machine
was doing nothing than sleeping, but the maximim number of childs
was already reached. This is no longer needed today, we do not run
many of these scripts anymore.

1 files changed, 5 insertions, 154 deletions

diff --git a/udev/udevd.c b/udev/udevd.c
index a711df53d4..a24ca92517 100644
--- a/udev/udevd.c
+++ b/udev/udevd.c
@@ -54,8 +54,6 @@
 
 /* maximum limit of forked childs */
 #define UDEVD_MAX_CHILDS		256
-/* start to throttle forking if maximum number of running childs in our session is reached */
-#define UDEVD_MAX_CHILDS_RUNNING	16
 
 static int debug;
 
@@ -95,7 +93,6 @@ static struct udev_rules rules;
 static struct udev_ctrl *udev_ctrl;
 static int uevent_netlink_sock = -1;
 static int inotify_fd = -1;
-static pid_t sid;
 
 static int signal_pipe[2] = {-1, -1};
 static volatile int sigchilds_waiting;
@@ -104,7 +101,6 @@ static volatile int reload_config;
 static int run_exec_q;
 static int stop_exec_q;
 static int max_childs;
-static int max_childs_running;
 static char udev_log_env[32];
 
 static LIST_HEAD(exec_list);
@@ -348,114 +344,6 @@ static int mem_size_mb(void)
 	return memsize;
 }
 
-static int cpu_count(void)
-{
-	FILE* f;
-	char buf[4096];
-	int count = 0;
-
-	f = fopen("/proc/stat", "r");
-	if (f == NULL)
-		return -1;
-
-	while (fgets(buf, sizeof(buf), f) != NULL) {
-		if (strncmp(buf, "cpu", 3) == 0 && isdigit(buf[3]))
-			count++;
-	}
-
-	fclose(f);
-	if (count == 0)
-		return -1;
-	return count;
-}
-
-static int running_processes(void)
-{
-	FILE* f;
-	char buf[4096];
-	int running = -1;
-
-	f = fopen("/proc/stat", "r");
-	if (f == NULL)
-		return -1;
-
-	while (fgets(buf, sizeof(buf), f) != NULL) {
-		int value;
-
-		if (sscanf(buf, "procs_running %u", &value) == 1) {
-			running = value;
-			break;
-		}
-	}
-
-	fclose(f);
-	return running;
-}
-
-/* return the number of process es in our session, count only until limit */
-static int running_processes_in_session(pid_t session, int limit)
-{
-	DIR *dir;
-	struct dirent *dent;
-	int running = 0;
-
-	dir = opendir("/proc");
-	if (!dir)
-		return -1;
-
-	/* read process info from /proc */
-	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
-		int f;
-		char procdir[64];
-		char line[256];
-		const char *pos;
-		char state;
-		pid_t ppid, pgrp, sess;
-		int len;
-
-		if (!isdigit(dent->d_name[0]))
-			continue;
-
-		snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
-		procdir[sizeof(procdir)-1] = '\0';
-
-		f = open(procdir, O_RDONLY);
-		if (f == -1)
-			continue;
-
-		len = read(f, line, sizeof(line)-1);
-		close(f);
-
-		if (len <= 0)
-			continue;
-		else
-			line[len] = '\0';
-
-		/* skip ugly program name */
-		pos = strrchr(line, ')') + 2;
-		if (pos == NULL)
-			continue;
-
-		if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
-			continue;
-
-		/* count only processes in our session */
-		if (sess != session)
-			continue;
-
-		/* count only running, no sleeping processes */
-		if (state != 'R')
-			continue;
-
-		running++;
-		if (limit > 0 && running >= limit)
-			break;
-	}
-	closedir(dir);
-
-	return running;
-}
-
 static int compare_devpath(const char *running, const char *waiting)
 {
 	int i;
@@ -524,8 +412,10 @@ static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 
 	/* check run queue for still running events */
 	list_for_each_entry(loop_msg, &running_list, node) {
-		if (limit && childs_count++ > limit) {
-			dbg(msg->udev, "%llu, maximum number (%i) of childs reached\n", msg->seqnum, childs_count);
+		childs_count++;
+
+		if (childs_count++ >= limit) {
+			info(msg->udev, "%llu, maximum number (%i) of childs reached\n", msg->seqnum, childs_count);
 			return 1;
 		}
 
@@ -565,27 +455,11 @@ static void msg_queue_manager(struct udev *udev)
 {
 	struct udevd_uevent_msg *loop_msg;
 	struct udevd_uevent_msg *tmp_msg;
-	int running;
 
 	if (list_empty(&exec_list))
 		return;
 
-	running = running_processes();
-	dbg(udev, "%d processes runnning on system\n", running);
-	if (running < 0)
-		running = max_childs_running;
-
 	list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
-		/* check running processes in our session and possibly throttle */
-		if (running >= max_childs_running) {
-			running = running_processes_in_session(sid, max_childs_running+10);
-			dbg(udev, "at least %d processes running in session\n", running);
-			if (running >= max_childs_running) {
-				dbg(udev, "delay seq %llu, too many processes already running\n", loop_msg->seqnum);
-				return;
-			}
-		}
-
 		/* serialize and wait for parent or child events */
 		if (devpath_busy(loop_msg, max_childs) != 0) {
 			dbg(udev, "delay seq %llu (%s)\n", loop_msg->seqnum, loop_msg->devpath);
@@ -595,7 +469,6 @@ static void msg_queue_manager(struct udev *udev)
 		/* move event to run list */
 		list_move_tail(&loop_msg->node, &running_list);
 		udev_event_run(loop_msg);
-		running++;
 		dbg(udev, "moved seq %llu to running list\n", loop_msg->seqnum);
 	}
 }
@@ -735,12 +608,6 @@ static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 		max_childs = i;
 	}
 
-	i = udev_ctrl_get_set_max_childs_running(ctrl_msg);
-	if (i > 0) {
-		info(udev, "udevd message (SET_MAX_CHILDS_RUNNING) received, max_childs_running=%i\n", i);
-		max_childs_running = i;
-	}
-
 	udev_ctrl_msg_unref(ctrl_msg);
 }
 
@@ -1079,10 +946,7 @@ int main(int argc, char *argv[])
 
 	chdir("/");
 	umask(022);
-
-	/* become session leader */
-	sid = setsid();
-	dbg(udev, "our session is %d\n", sid);
+	setsid();
 
 	/* OOM_DISABLE == -17 */
 	fd = open("/proc/self/oom_adj", O_RDWR);
@@ -1149,19 +1013,6 @@ int main(int argc, char *argv[])
 	}
 	info(udev, "initialize max_childs to %u\n", max_childs);
 
-	/* start to throttle forking if maximum number of _running_ childs is reached */
-	value = getenv("UDEVD_MAX_CHILDS_RUNNING");
-	if (value)
-		max_childs_running = strtoull(value, NULL, 10);
-	else {
-		int cpus = cpu_count();
-		if (cpus > 0)
-			max_childs_running = 8 + (8 * cpus);
-		else
-			max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
-	}
-	info(udev, "initialize max_childs_running to %u\n", max_childs_running);
-
 	/* clear environment for forked event processes */
 	clearenv();