zed: don't malloc() global zed_conf instance, optimise zed_conf layout

It's all of 40 bytes with 4-byte pointers and 64 with 8-byte ones
(previously 44 and 88, respectively) ‒
there's no reason it can't live on the stack

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Ahelenia Ziemiańska <[email protected]>
Closes #11860

3 files changed, 48 insertions, 63 deletions

diff --git a/cmd/zed/zed.c b/cmd/zed/zed.c
index be1848ef1..e56b45fa7 100644
--- a/cmd/zed/zed.c
+++ b/cmd/zed/zed.c
@@ -216,15 +216,15 @@ _finish_daemonize(void)
 int
 main(int argc, char *argv[])
 {
-	struct zed_conf *zcp;
+	struct zed_conf zcp;
 	uint64_t saved_eid;
 	int64_t saved_etime[2];
 
 	zed_log_init(argv[0]);
 	zed_log_stderr_open(LOG_NOTICE);
-	zcp = zed_conf_create();
-	zed_conf_parse_opts(zcp, argc, argv);
-	if (zcp->do_verbose)
+	zed_conf_init(&zcp);
+	zed_conf_parse_opts(&zcp, argc, argv);
+	if (zcp.do_verbose)
 		zed_log_stderr_open(LOG_INFO);
 
 	if (geteuid() != 0)
@@ -237,32 +237,32 @@ main(int argc, char *argv[])
 	if (chdir("/") < 0)
 		zed_log_die("Failed to change to root directory");
 
-	if (zed_conf_scan_dir(zcp) < 0)
+	if (zed_conf_scan_dir(&zcp) < 0)
 		exit(EXIT_FAILURE);
 
-	if (!zcp->do_foreground) {
+	if (!zcp.do_foreground) {
 		_start_daemonize();
 		zed_log_syslog_open(LOG_DAEMON);
 	}
 	_setup_sig_handlers();
 
-	if (zcp->do_memlock)
+	if (zcp.do_memlock)
 		_lock_memory();
 
-	if ((zed_conf_write_pid(zcp) < 0) && (!zcp->do_force))
+	if ((zed_conf_write_pid(&zcp) < 0) && (!zcp.do_force))
 		exit(EXIT_FAILURE);
 
-	if (!zcp->do_foreground)
+	if (!zcp.do_foreground)
 		_finish_daemonize();
 
 	zed_log_msg(LOG_NOTICE,
 	    "ZFS Event Daemon %s-%s (PID %d)",
 	    ZFS_META_VERSION, ZFS_META_RELEASE, (int)getpid());
 
-	if (zed_conf_open_state(zcp) < 0)
+	if (zed_conf_open_state(&zcp) < 0)
 		exit(EXIT_FAILURE);
 
-	if (zed_conf_read_state(zcp, &saved_eid, saved_etime) < 0)
+	if (zed_conf_read_state(&zcp, &saved_eid, saved_etime) < 0)
 		exit(EXIT_FAILURE);
 
 idle:
@@ -271,24 +271,24 @@ idle:
 	 * successful.
 	 */
 	do {
-		if (!zed_event_init(zcp))
+		if (!zed_event_init(&zcp))
 			break;
 		/* Wait for some time and try again. tunable? */
 		sleep(30);
-	} while (!_got_exit && zcp->do_idle);
+	} while (!_got_exit && zcp.do_idle);
 
 	if (_got_exit)
 		goto out;
 
-	zed_event_seek(zcp, saved_eid, saved_etime);
+	zed_event_seek(&zcp, saved_eid, saved_etime);
 
 	while (!_got_exit) {
 		int rv;
 		if (_got_hup) {
 			_got_hup = 0;
-			(void) zed_conf_scan_dir(zcp);
+			(void) zed_conf_scan_dir(&zcp);
 		}
-		rv = zed_event_service(zcp);
+		rv = zed_event_service(&zcp);
 
 		/* ENODEV: When kernel module is unloaded (osx) */
 		if (rv == ENODEV)
@@ -296,13 +296,13 @@ idle:
 	}
 
 	zed_log_msg(LOG_NOTICE, "Exiting");
-	zed_event_fini(zcp);
+	zed_event_fini(&zcp);
 
-	if (zcp->do_idle && !_got_exit)
+	if (zcp.do_idle && !_got_exit)
 		goto idle;
 
 out:
-	zed_conf_destroy(zcp);
+	zed_conf_destroy(&zcp);
 	zed_log_fini();
 	exit(EXIT_SUCCESS);
 }
diff --git a/cmd/zed/zed_conf.c b/cmd/zed/zed_conf.c
index 5f895109d..9e67363f7 100644
--- a/cmd/zed/zed_conf.c
+++ b/cmd/zed/zed_conf.c
@@ -32,38 +32,26 @@
 #include "zed_strings.h"
 
 /*
- * Return a new configuration with default values.
+ * Initialise the configuration with default values.
  */
-struct zed_conf *
-zed_conf_create(void)
+void
+zed_conf_init(struct zed_conf *zcp)
 {
-	struct zed_conf *zcp;
-
-	zcp = calloc(1, sizeof (*zcp));
-	if (!zcp)
-		goto nomem;
-
-	zcp->pid_fd = -1;
-	zcp->zedlets = NULL;		/* created via zed_conf_scan_dir() */
-	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;
+	memset(zcp, 0, sizeof (*zcp));
 
-	if (!(zcp->pid_file = strdup(ZED_PID_FILE)))
-		goto nomem;
+	/* zcp->zfs_hdl opened in zed_event_init() */
+	/* zcp->zedlets created in zed_conf_scan_dir() */
 
-	if (!(zcp->zedlet_dir = strdup(ZED_ZEDLET_DIR)))
-		goto nomem;
+	zcp->pid_fd = -1;		/* opened in zed_conf_write_pid() */
+	zcp->state_fd = -1;		/* opened in zed_conf_open_state() */
+	zcp->zevent_fd = -1;		/* opened in zed_event_init() */
 
-	if (!(zcp->state_file = strdup(ZED_STATE_FILE)))
-		goto nomem;
-
-	return (zcp);
+	zcp->max_jobs = 16;
 
-nomem:
-	zed_log_die("Failed to create conf: %s", strerror(errno));
-	return (NULL);
+	if (!(zcp->pid_file = strdup(ZED_PID_FILE)) ||
+	    !(zcp->zedlet_dir = strdup(ZED_ZEDLET_DIR)) ||
+	    !(zcp->state_file = strdup(ZED_STATE_FILE)))
+		zed_log_die("Failed to create conf: %s", strerror(errno));
 }
 
 /*
@@ -74,9 +62,6 @@ nomem:
 void
 zed_conf_destroy(struct zed_conf *zcp)
 {
-	if (!zcp)
-		return;
-
 	if (zcp->state_fd >= 0) {
 		if (close(zcp->state_fd) < 0)
 			zed_log_msg(LOG_WARNING,
@@ -113,7 +98,6 @@ zed_conf_destroy(struct zed_conf *zcp)
 		zed_strings_destroy(zcp->zedlets);
 		zcp->zedlets = NULL;
 	}
-	free(zcp);
 }
 
 /*
diff --git a/cmd/zed/zed_conf.h b/cmd/zed/zed_conf.h
index c0691ddbc..b2dc09c51 100644
--- a/cmd/zed/zed_conf.h
+++ b/cmd/zed/zed_conf.h
@@ -20,26 +20,29 @@
 #include "zed_strings.h"
 
 struct zed_conf {
-	unsigned	do_force:1;		/* true if force enabled */
-	unsigned	do_foreground:1;	/* true if run in foreground */
-	unsigned	do_memlock:1;		/* true if locking memory */
-	unsigned	do_verbose:1;		/* true if verbosity enabled */
-	unsigned	do_zero:1;		/* true if zeroing state */
-	unsigned	do_idle:1;		/* true if idle enabled */
 	char		*pid_file;		/* abs path to pid file */
-	int		pid_fd;			/* fd to pid file for lock */
 	char		*zedlet_dir;		/* abs path to zedlet dir */
-	zed_strings_t	*zedlets;		/* names of enabled zedlets */
 	char		*state_file;		/* abs path to state file */
-	int		state_fd;		/* fd to state file */
+
 	libzfs_handle_t	*zfs_hdl;		/* handle to libzfs */
-	int		zevent_fd;		/* fd for access to zevents */
+	zed_strings_t	*zedlets;		/* names of enabled zedlets */
 	char		*path;		/* custom $PATH for zedlets to use */
+
+	int		pid_fd;			/* fd to pid file for lock */
+	int		state_fd;		/* fd to state file */
+	int		zevent_fd;		/* fd for access to zevents */
+
 	int16_t max_jobs;		/* max zedlets to run at one time */
-};
 
-struct zed_conf *zed_conf_create(void);
+	boolean_t	do_force:1;		/* true if force enabled */
+	boolean_t	do_foreground:1;	/* true if run in foreground */
+	boolean_t	do_memlock:1;		/* true if locking memory */
+	boolean_t	do_verbose:1;		/* true if verbosity enabled */
+	boolean_t	do_zero:1;		/* true if zeroing state */
+	boolean_t	do_idle:1;		/* true if idle enabled */
+};
 
+void zed_conf_init(struct zed_conf *zcp);
 void zed_conf_destroy(struct zed_conf *zcp);
 
 void zed_conf_parse_opts(struct zed_conf *zcp, int argc, char **argv);
@@ -49,9 +52,7 @@ int zed_conf_scan_dir(struct zed_conf *zcp);
 int zed_conf_write_pid(struct zed_conf *zcp);
 
 int zed_conf_open_state(struct zed_conf *zcp);
-
 int zed_conf_read_state(struct zed_conf *zcp, uint64_t *eidp, int64_t etime[]);
-
 int zed_conf_write_state(struct zed_conf *zcp, uint64_t eid, int64_t etime[]);
 
 #endif	/* !ZED_CONF_H */