diff --git a/cmd/zed/agents/zfs_agents.c b/cmd/zed/agents/zfs_agents.c
index 67b7951b0e65..35dd818ff80d 100644
--- a/cmd/zed/agents/zfs_agents.c
+++ b/cmd/zed/agents/zfs_agents.c
@@ -392,6 +392,7 @@ zfs_agent_init(libzfs_handle_t *zfs_hdl)
 		list_destroy(&agent_events);
 		zed_log_die("Failed to initialize agents");
 	}
+	pthread_setname_np(g_agents_tid, "agents");
 }
 
 void
diff --git a/cmd/zed/agents/zfs_mod.c b/cmd/zed/agents/zfs_mod.c
index 4a58e1f1dbd3..b564f2b12a26 100644
--- a/cmd/zed/agents/zfs_mod.c
+++ b/cmd/zed/agents/zfs_mod.c
@@ -918,6 +918,7 @@ zfs_slm_init()
 		return (-1);
 	}
 
+	pthread_setname_np(g_zfs_tid, "enum-pools");
 	list_create(&g_device_list, sizeof (struct pendingdev),
 	    offsetof(struct pendingdev, pd_node));
 
diff --git a/cmd/zed/zed.c b/cmd/zed/zed.c
index 907b8af0d01f..349e4d01b135 100644
--- a/cmd/zed/zed.c
+++ b/cmd/zed/zed.c
@@ -60,8 +60,8 @@ _setup_sig_handlers(void)
 		zed_log_die("Failed to initialize sigset");
 
 	sa.sa_flags = SA_RESTART;
-	sa.sa_handler = SIG_IGN;
 
+	sa.sa_handler = SIG_IGN;
 	if (sigaction(SIGPIPE, &sa, NULL) < 0)
 		zed_log_die("Failed to ignore SIGPIPE");
 
@@ -75,6 +75,10 @@ _setup_sig_handlers(void)
 	sa.sa_handler = _hup_handler;
 	if (sigaction(SIGHUP, &sa, NULL) < 0)
 		zed_log_die("Failed to register SIGHUP handler");
+
+	(void) sigaddset(&sa.sa_mask, SIGCHLD);
+	if (pthread_sigmask(SIG_BLOCK, &sa.sa_mask, NULL) < 0)
+		zed_log_die("Failed to block SIGCHLD");
 }
 
 /*
diff --git a/cmd/zed/zed_conf.c b/cmd/zed/zed_conf.c
index c15f01fecb41..44ccc2557b2d 100644
--- a/cmd/zed/zed_conf.c
+++ b/cmd/zed/zed_conf.c
@@ -51,6 +51,7 @@ zed_conf_create(void)
 	zcp->state_fd = -1;		/* opened via zed_conf_open_state() */
 	zcp->zfs_hdl = NULL;		/* opened via zed_event_init() */
 	zcp->zevent_fd = -1;		/* opened via zed_event_init() */
+	zcp->max_jobs = 16;
 
 	if (!(zcp->conf_file = strdup(ZED_CONF_FILE)))
 		goto nomem;
@@ -172,6 +173,8 @@ _zed_conf_display_help(const char *prog, int got_err)
 	    "Write daemon's PID to FILE.", ZED_PID_FILE);
 	fprintf(fp, "%*c%*s %s [%s]\n", w1, 0x20, -w2, "-s FILE",
 	    "Write daemon's state to FILE.", ZED_STATE_FILE);
+	fprintf(fp, "%*c%*s %s [%d]\n", w1, 0x20, -w2, "-j JOBS",
+	    "Start at most JOBS at once.", 16);
 	fprintf(fp, "\n");
 
 	exit(got_err ? EXIT_FAILURE : EXIT_SUCCESS);
@@ -251,8 +254,9 @@ _zed_conf_parse_path(char **resultp, const char *path)
 void
 zed_conf_parse_opts(struct zed_conf *zcp, int argc, char **argv)
 {
-	const char * const opts = ":hLVc:d:p:P:s:vfFMZI";
+	const char * const opts = ":hLVc:d:p:P:s:vfFMZIj:";
 	int opt;
+	unsigned long raw;
 
 	if (!zcp || !argv || !argv[0])
 		zed_log_die("Failed to parse options: Internal error");
@@ -303,6 +307,17 @@ zed_conf_parse_opts(struct zed_conf *zcp, int argc, char **argv)
 		case 'Z':
 			zcp->do_zero = 1;
 			break;
+		case 'j':
+			errno = 0;
+			raw = strtoul(optarg, NULL, 0);
+			if (errno == ERANGE || raw > INT16_MAX) {
+				zed_log_die("%lu is too many jobs", raw);
+			} if (raw == 0) {
+				zed_log_die("0 jobs makes no sense");
+			} else {
+				zcp->max_jobs = raw;
+			}
+			break;
 		case '?':
 		default:
 			if (optopt == '?')
diff --git a/cmd/zed/zed_conf.h b/cmd/zed/zed_conf.h
index f44d20382968..7599af46b11e 100644
--- a/cmd/zed/zed_conf.h
+++ b/cmd/zed/zed_conf.h
@@ -39,6 +39,7 @@ struct zed_conf {
 	libzfs_handle_t	*zfs_hdl;		/* handle to libzfs */
 	int		zevent_fd;		/* fd for access to zevents */
 	char		*path;		/* custom $PATH for zedlets to use */
+	int16_t max_jobs;		/* max zedlets to run at one time */
 };
 
 struct zed_conf *zed_conf_create(void);
diff --git a/cmd/zed/zed_disk_event.c b/cmd/zed/zed_disk_event.c
index 174d24523253..6ec566cff3ca 100644
--- a/cmd/zed/zed_disk_event.c
+++ b/cmd/zed/zed_disk_event.c
@@ -379,6 +379,7 @@ zed_disk_event_init()
 		return (-1);
 	}
 
+	pthread_setname_np(g_mon_tid, "udev monitor");
 	zed_log_msg(LOG_INFO, "zed_disk_event_init");
 
 	return (0);
diff --git a/cmd/zed/zed_event.c b/cmd/zed/zed_event.c
index 8892087d6e62..6d746b7b139a 100644
--- a/cmd/zed/zed_event.c
+++ b/cmd/zed/zed_event.c
@@ -15,7 +15,7 @@
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <libzfs.h>			/* FIXME: Replace with libzfs_core. */
+#include <libzfs_core.h>
 #include <paths.h>
 #include <stdarg.h>
 #include <stdio.h>
@@ -96,6 +96,8 @@ zed_event_fini(struct zed_conf *zcp)
 		libzfs_fini(zcp->zfs_hdl);
 		zcp->zfs_hdl = NULL;
 	}
+
+	zed_exec_fini();
 }
 
 /*
@@ -953,8 +955,7 @@ zed_event_service(struct zed_conf *zcp)
 
 		_zed_event_add_time_strings(eid, zsp, etime);
 
-		zed_exec_process(eid, class, subclass,
-		    zcp->zedlet_dir, zcp->zedlets, zsp, zcp->zevent_fd);
+		zed_exec_process(eid, class, subclass, zcp, zsp);
 
 		zed_conf_write_state(zcp, eid, etime);
 
diff --git a/cmd/zed/zed_exec.c b/cmd/zed/zed_exec.c
index e8f510213868..1fbac429683b 100644
--- a/cmd/zed/zed_exec.c
+++ b/cmd/zed/zed_exec.c
@@ -18,10 +18,13 @@
 #include <fcntl.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stddef.h>
+#include <sys/avl.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
 #include <time.h>
 #include <unistd.h>
+#include <pthread.h>
 #include "zed_exec.h"
 #include "zed_file.h"
 #include "zed_log.h"
@@ -29,6 +32,39 @@
 
 #define	ZEVENT_FILENO	3
 
+struct launched_process_node {
+	avl_node_t node;
+	pid_t pid;
+	uint64_t eid;
+	char *name;
+};
+
+static int
+_launched_process_node_compare(const void *x1, const void *x2)
+{
+	pid_t p1;
+	pid_t p2;
+
+	assert(x1 != NULL);
+	assert(x2 != NULL);
+
+	p1 = ((const struct launched_process_node *) x1)->pid;
+	p2 = ((const struct launched_process_node *) x2)->pid;
+
+	if (p1 < p2)
+		return (-1);
+	else if (p1 == p2)
+		return (0);
+	else
+		return (1);
+}
+
+static pthread_t _reap_children_tid = (pthread_t)-1;
+static volatile boolean_t _reap_children_stop;
+static avl_tree_t _launched_processes;
+static pthread_mutex_t _launched_processes_lock = PTHREAD_MUTEX_INITIALIZER;
+static int16_t _launched_processes_limit;
+
 /*
  * Create an environment string array for passing to execve() using the
  * NAME=VALUE strings in container [zsp].
@@ -85,14 +121,20 @@ _zed_exec_fork_child(uint64_t eid, const char *dir, const char *prog,
 	int n;
 	pid_t pid;
 	int fd;
-	pid_t wpid;
-	int status;
+	struct launched_process_node *node;
+	sigset_t mask;
+	struct timespec launch_timeout =
+		{ .tv_sec = 0, .tv_nsec = 200 * 1000 * 1000, };
 
 	assert(dir != NULL);
 	assert(prog != NULL);
 	assert(env != NULL);
 	assert(zfd >= 0);
 
+	while (__atomic_load_n(&_launched_processes_limit,
+	    __ATOMIC_SEQ_CST) <= 0)
+		(void) nanosleep(&launch_timeout, NULL);
+
 	n = snprintf(path, sizeof (path), "%s/%s", dir, prog);
 	if ((n < 0) || (n >= sizeof (path))) {
 		zed_log_msg(LOG_WARNING,
@@ -107,6 +149,9 @@ _zed_exec_fork_child(uint64_t eid, const char *dir, const char *prog,
 		    prog, eid, strerror(errno));
 		return;
 	} else if (pid == 0) {
+		(void) sigemptyset(&mask);
+		(void) sigprocmask(SIG_SETMASK, &mask, NULL);
+
 		(void) umask(022);
 		if ((fd = open("/dev/null", O_RDWR)) != -1) {
 			(void) dup2(fd, STDIN_FILENO);
@@ -121,80 +166,135 @@ _zed_exec_fork_child(uint64_t eid, const char *dir, const char *prog,
 
 	/* parent process */
 
+	__atomic_sub_fetch(&_launched_processes_limit, 1, __ATOMIC_SEQ_CST);
 	zed_log_msg(LOG_INFO, "Invoking \"%s\" eid=%llu pid=%d",
 	    prog, eid, pid);
 
-	/* FIXME: Timeout rogue child processes with sigalarm? */
-
-	/*
-	 * Wait for child process using WNOHANG to limit
-	 * the time spent waiting to 10 seconds (10,000ms).
-	 */
-	for (n = 0; n < 1000; n++) {
-		wpid = waitpid(pid, &status, WNOHANG);
-		if (wpid == (pid_t)-1) {
-			if (errno == EINTR)
-				continue;
-			zed_log_msg(LOG_WARNING,
-			    "Failed to wait for \"%s\" eid=%llu pid=%d",
-			    prog, eid, pid);
-			break;
-		} else if (wpid == 0) {
-			struct timespec t;
-
-			/* child still running */
-			t.tv_sec = 0;
-			t.tv_nsec = 10000000;	/* 10ms */
-			(void) nanosleep(&t, NULL);
-			continue;
-		}
+	node = calloc(1, sizeof (*node));
+	if (node) {
+		node->pid = pid;
+		node->eid = eid;
+		node->name = strdup(prog);
+		(void) pthread_mutex_lock(&_launched_processes_lock);
+		avl_add(&_launched_processes, node);
+		(void) pthread_mutex_unlock(&_launched_processes_lock);
+	}
+}
+
+static void
+_nop(int sig)
+{}
+
+static void *
+_reap_children(void *arg)
+{
+	struct launched_process_node node, *pnode;
+	pid_t pid;
+	int status;
+	struct sigaction sa = {};
+
+	(void) sigfillset(&sa.sa_mask);
+	(void) sigdelset(&sa.sa_mask, SIGCHLD);
+	(void) pthread_sigmask(SIG_SETMASK, &sa.sa_mask, NULL);
+
+	(void) sigemptyset(&sa.sa_mask);
+	sa.sa_handler = _nop;
+	sa.sa_flags = SA_NOCLDSTOP;
+	(void) sigaction(SIGCHLD, &sa, NULL);
 
-		if (WIFEXITED(status)) {
-			zed_log_msg(LOG_INFO,
-			    "Finished \"%s\" eid=%llu pid=%d exit=%d",
-			    prog, eid, pid, WEXITSTATUS(status));
-		} else if (WIFSIGNALED(status)) {
-			zed_log_msg(LOG_INFO,
-			    "Finished \"%s\" eid=%llu pid=%d sig=%d/%s",
-			    prog, eid, pid, WTERMSIG(status),
-			    strsignal(WTERMSIG(status)));
+	for (_reap_children_stop = B_FALSE; !_reap_children_stop; ) {
+		pid = waitpid(0, &status, 0);
+
+		if (pid == (pid_t)-1) {
+			if (errno == ECHILD)
+				pause();
+			else if (errno != EINTR)
+				zed_log_msg(LOG_WARNING,
+				    "Failed to wait for children: %s",
+				    strerror(errno));
 		} else {
-			zed_log_msg(LOG_INFO,
-			    "Finished \"%s\" eid=%llu pid=%d status=0x%X",
-			    prog, eid, (unsigned int) status);
+			memset(&node, 0, sizeof (node));
+			node.pid = pid;
+			(void) pthread_mutex_lock(&_launched_processes_lock);
+			pnode = avl_find(&_launched_processes, &node, NULL);
+			if (pnode) {
+				memcpy(&node, pnode, sizeof (node));
+
+				avl_remove(&_launched_processes, pnode);
+				free(pnode);
+			}
+			(void) pthread_mutex_unlock(&_launched_processes_lock);
+			__atomic_add_fetch(&_launched_processes_limit, 1,
+			    __ATOMIC_SEQ_CST);
+
+			if (WIFEXITED(status)) {
+				zed_log_msg(LOG_INFO,
+				    "Finished \"%s\" eid=%llu pid=%d exit=%d",
+				    node.name, node.eid, pid,
+				    WEXITSTATUS(status));
+			} else if (WIFSIGNALED(status)) {
+				zed_log_msg(LOG_INFO,
+				    "Finished \"%s\" eid=%llu pid=%d sig=%d/%s",
+				    node.name, node.eid, pid, WTERMSIG(status),
+				    strsignal(WTERMSIG(status)));
+			} else {
+				zed_log_msg(LOG_INFO,
+				    "Finished \"%s\" eid=%llu pid=%d "
+				    "status=0x%X",
+				    node.name, node.eid, (unsigned int) status);
+			}
+
+			free(node.name);
 		}
-		break;
 	}
 
-	/*
-	 * kill child process after 10 seconds
-	 */
-	if (wpid == 0) {
-		zed_log_msg(LOG_WARNING, "Killing hung \"%s\" pid=%d",
-		    prog, pid);
-		(void) kill(pid, SIGKILL);
-		(void) waitpid(pid, &status, 0);
+	return (NULL);
+}
+
+void
+zed_exec_fini(void)
+{
+	struct launched_process_node *node;
+	void *ck = NULL;
+
+	if (_reap_children_tid == (pthread_t)-1)
+		return;
+
+	_reap_children_stop = B_TRUE;
+	(void) pthread_kill(_reap_children_tid, SIGCHLD);
+	(void) pthread_join(_reap_children_tid, NULL);
+
+	while ((node = avl_destroy_nodes(&_launched_processes, &ck)) != NULL) {
+		free(node->name);
+		free(node);
 	}
+	avl_destroy(&_launched_processes);
+
+	(void) pthread_mutex_destroy(&_launched_processes_lock);
+	(void) pthread_mutex_init(&_launched_processes_lock, NULL);
+
+	_reap_children_tid = (pthread_t)-1;
 }
 
 /*
  * Process the event [eid] by synchronously invoking all zedlets with a
  * matching class prefix.
  *
- * Each executable in [zedlets] from the directory [dir] is matched against
- * the event's [class], [subclass], and the "all" class (which matches
- * all events).  Every zedlet with a matching class prefix is invoked.
+ * Each executable in [zcp->zedlets] from the directory [zcp->zedlet_dir]
+ * is matched against the event's [class], [subclass], and the "all" class
+ * (which matches all events).
+ * Every zedlet with a matching class prefix is invoked.
  * The NAME=VALUE strings in [envs] will be passed to the zedlet as
  * environment variables.
  *
- * The file descriptor [zfd] is the zevent_fd used to track the
+ * The file descriptor [zcp->zevent_fd] is the zevent_fd used to track the
  * current cursor location within the zevent nvlist.
  *
  * Return 0 on success, -1 on error.
  */
 int
 zed_exec_process(uint64_t eid, const char *class, const char *subclass,
-    const char *dir, zed_strings_t *zedlets, zed_strings_t *envs, int zfd)
+    struct zed_conf *zcp, zed_strings_t *envs)
 {
 	const char *class_strings[4];
 	const char *allclass = "all";
@@ -203,9 +303,22 @@ zed_exec_process(uint64_t eid, const char *class, const char *subclass,
 	char **e;
 	int n;
 
-	if (!dir || !zedlets || !envs || zfd < 0)
+	if (!zcp->zedlet_dir || !zcp->zedlets || !envs || zcp->zevent_fd < 0)
 		return (-1);
 
+	if (_reap_children_tid == (pthread_t)-1) {
+		_launched_processes_limit = zcp->max_jobs;
+
+		if (pthread_create(&_reap_children_tid, NULL,
+		    _reap_children, NULL) != 0)
+			return (-1);
+		pthread_setname_np(_reap_children_tid, "reap ZEDLETs");
+
+		avl_create(&_launched_processes, _launched_process_node_compare,
+		    sizeof (struct launched_process_node),
+		    offsetof(struct launched_process_node, node));
+	}
+
 	csp = class_strings;
 
 	if (class)
@@ -221,11 +334,13 @@ zed_exec_process(uint64_t eid, const char *class, const char *subclass,
 
 	e = _zed_exec_create_env(envs);
 
-	for (z = zed_strings_first(zedlets); z; z = zed_strings_next(zedlets)) {
+	for (z = zed_strings_first(zcp->zedlets); z;
+	    z = zed_strings_next(zcp->zedlets)) {
 		for (csp = class_strings; *csp; csp++) {
 			n = strlen(*csp);
 			if ((strncmp(z, *csp, n) == 0) && !isalpha(z[n]))
-				_zed_exec_fork_child(eid, dir, z, e, zfd);
+				_zed_exec_fork_child(eid, zcp->zedlet_dir,
+				    z, e, zcp->zevent_fd);
 		}
 	}
 	free(e);
diff --git a/cmd/zed/zed_exec.h b/cmd/zed/zed_exec.h
index 5eb9170abfe3..2a7f721f0030 100644
--- a/cmd/zed/zed_exec.h
+++ b/cmd/zed/zed_exec.h
@@ -17,9 +17,11 @@
 
 #include <stdint.h>
 #include "zed_strings.h"
+#include "zed_conf.h"
+
+void zed_exec_fini(void);
 
 int zed_exec_process(uint64_t eid, const char *class, const char *subclass,
-    const char *dir, zed_strings_t *zedlets, zed_strings_t *envs,
-    int zevent_fd);
+    struct zed_conf *zcp, zed_strings_t *envs);
 
 #endif	/* !ZED_EXEC_H */
diff --git a/cmd/zed/zed_file.c b/cmd/zed/zed_file.c
index b51b1ca9dcf6..4437892e9058 100644
--- a/cmd/zed/zed_file.c
+++ b/cmd/zed/zed_file.c
@@ -187,31 +187,3 @@ zed_file_close_from(int lowfd)
 
 	errno = errno_bak;
 }
-
-/*
- * Set the CLOEXEC flag on file descriptor [fd] so it will be automatically
- * closed upon successful execution of one of the exec functions.
- * Return 0 on success, or -1 on error.
- *
- * FIXME: No longer needed?
- */
-int
-zed_file_close_on_exec(int fd)
-{
-	int flags;
-
-	if (fd < 0) {
-		errno = EBADF;
-		return (-1);
-	}
-	flags = fcntl(fd, F_GETFD);
-	if (flags == -1)
-		return (-1);
-
-	flags |= FD_CLOEXEC;
-
-	if (fcntl(fd, F_SETFD, flags) == -1)
-		return (-1);
-
-	return (0);
-}
diff --git a/cmd/zed/zed_file.h b/cmd/zed/zed_file.h
index 7dcae83810ef..28a5dd0ccac3 100644
--- a/cmd/zed/zed_file.h
+++ b/cmd/zed/zed_file.h
@@ -30,6 +30,4 @@ pid_t zed_file_is_locked(int fd);
 
 void zed_file_close_from(int fd);
 
-int zed_file_close_on_exec(int fd);
-
 #endif	/* !ZED_FILE_H */
diff --git a/man/man8/zed.8.in b/man/man8/zed.8.in
index e32a89de8a0f..db9f4a816311 100644
--- a/man/man8/zed.8.in
+++ b/man/man8/zed.8.in
@@ -29,6 +29,7 @@ ZED \- ZFS Event Daemon
 [\fB\-p\fR \fIpidfile\fR]
 [\fB\-P\fR \fIpath\fR]
 [\fB\-s\fR \fIstatefile\fR]
+[\fB\-j\fR \fIjobs\fR]
 [\fB\-v\fR]
 [\fB\-V\fR]
 [\fB\-Z\fR]
@@ -95,6 +96,11 @@ it in production!
 .TP
 .BI \-s\  statefile
 Write the daemon's state to the specified file.
+.TP
+.BI \-j\  jobs
+Allow at most \fIjobs\fR ZEDLETs to run concurrently,
+delaying execution of new ones until they finish.
+Defaults to 16.
 .SH ZEVENTS
 .PP
 A zevent is comprised of a list of nvpairs (name/value pairs).  Each zevent
@@ -231,12 +237,6 @@ Terminate the daemon.
 
 .SH BUGS
 .PP
-Events are processed synchronously by a single thread.  This can delay the
-processing of simultaneous zevents.
-.PP
-ZEDLETs are killed after a maximum of ten seconds.
-This can lead to a violation of a ZEDLET's atomicity assumptions.
-.PP
 The ownership and permissions of the \fIenabled-zedlets\fR directory (along
 with all parent directories) are not checked.  If any of these directories
 are improperly owned or permissioned, an unprivileged user could insert a
diff --git a/tests/zfs-tests/include/libtest.shlib b/tests/zfs-tests/include/libtest.shlib
index bd77bae7d967..c3b1adc93a4e 100644
--- a/tests/zfs-tests/include/libtest.shlib
+++ b/tests/zfs-tests/include/libtest.shlib
@@ -3705,8 +3705,8 @@ function zed_start
 		# run ZED in the background and redirect foreground logging
 		# output to $ZED_LOG.
 		log_must truncate -s 0 $ZED_DEBUG_LOG
-		log_must eval "zed -vF -d $ZEDLET_DIR -p $ZEDLET_DIR/zed.pid -P $PATH" \
-		    "-s $ZEDLET_DIR/state 2>$ZED_LOG &"
+		log_must eval "zed -vF -d $ZEDLET_DIR -P $PATH" \
+		    "-s $ZEDLET_DIR/state -j 1 2>$ZED_LOG &"
 	fi
 
 	return 0
@@ -3722,14 +3722,13 @@ function zed_stop
 	fi
 
 	log_note "Stopping ZED"
-	if [[ -f ${ZEDLET_DIR}/zed.pid ]]; then
-		zedpid=$(<${ZEDLET_DIR}/zed.pid)
-		kill $zedpid
-		while ps -p $zedpid > /dev/null; do
-			sleep 1
-		done
-		rm -f ${ZEDLET_DIR}/zed.pid
-	fi
+	while true; do
+		zedpids="$(pgrep -x zed)"
+		[ "$?" -ne 0 ] && break
+
+		log_must kill $zedpids
+		sleep 1
+	done
 	return 0
 }
 
diff --git a/tests/zfs-tests/tests/functional/events/zed_rc_filter.ksh b/tests/zfs-tests/tests/functional/events/zed_rc_filter.ksh
index 44652ee4cf12..0bef0ef1f96b 100755
--- a/tests/zfs-tests/tests/functional/events/zed_rc_filter.ksh
+++ b/tests/zfs-tests/tests/functional/events/zed_rc_filter.ksh
@@ -49,6 +49,7 @@ log_assert "Verify zpool sub-commands generate expected events"
 log_onexit cleanup
 
 log_must zpool events -c
+log_must zed_stop
 log_must zed_start
 
 # Backup our zed.rc