mem-snap: Redefine CLI options for mem snapshot

They are not documented, thus OK for now. Two options --
* one to specify where the parent images are
* one to reset dirty memory tracking

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

crtools.c

@@ -113,8 +113,9 @@ int main(int argc, char *argv[])
 			{ "page-server", no_argument, 0, 50},
 			{ "address", required_argument, 0, 51},
 			{ "port", required_argument, 0, 52},
-			{ "snapshot", optional_argument, 0, 53},
+			{ "prev-images-dir", required_argument, 0, 53},
 			{ "ms", no_argument, 0, 54},
+			{ "track-mem", no_argument, 0, 55},
 			{ },
 		};
 
@@ -262,8 +263,10 @@ int main(int argc, char *argv[])
 			opts.handle_file_locks = true;
 			break;
 		case 53:
-			opts.mem_snapshot = true;
-			opts.snap_parent = optarg;
+			opts.img_parent = optarg;
+			break;
+		case 55:
+			opts.track_mem = true;
 			break;
 		case 54:
 			opts.check_ms_kernel = true;
@@ -287,8 +290,8 @@ int main(int argc, char *argv[])
 			return ret;
 	}
 
-	if (opts.mem_snapshot)
-		pr_info("Will do snapshot from %s\n", opts.snap_parent);
+	if (opts.img_parent)
+		pr_info("Will do snapshot from %s\n", opts.img_parent);
 
 	ret = open_image_dir();
 	if (ret < 0) {

image.c

@@ -332,8 +332,8 @@ int open_image_dir(void)
 
 	close(fd);
 
-	if (opts.snap_parent) {
-		ret = symlink(opts.snap_parent, CR_PARENT_LINK);
+	if (opts.img_parent) {
+		ret = symlink(opts.img_parent, CR_PARENT_LINK);
 		if (ret < 0) {
 			pr_perror("Can't link parent snapshot.");
 			goto err;

include/crtools.h

@@ -119,8 +119,8 @@ struct cr_options {
 	struct list_head	scripts;
 	bool			use_page_server;
 	struct sockaddr_in	ps_addr;
-	bool			mem_snapshot;
-	char			*snap_parent;
+	bool			track_mem;
+	char			*img_parent;
 };
 
 extern struct cr_options opts;

mem.c

@@ -45,9 +45,15 @@ static int task_reset_dirty_track(int pid)
 	int fd, ret;
 	char cmd[] = "4";
 
-	if (!opts.mem_snapshot)
+	if (!opts.track_mem)
 		return 0;
 
+	if (!kerndat_has_dirty_track) {
+		pr_err("Kernel doesn't support dirty tracking. "
+				"No snapshot available.\n");
+		return -1;
+	}
+
 	pr_info("Reset %d's dirty tracking\n", pid);
 	fd = open_proc_rw(pid, "clear_refs");
 	if (fd < 0)
@@ -71,15 +77,6 @@ static struct mem_snap_ctx *mem_snap_init(struct parasite_ctl *ctl)
 	int p_fd, pm_fd;
 	PagemapHead *h;
 
-	if (!opts.mem_snapshot)
-		return NULL;
-
-	if (!kerndat_has_dirty_track) {
-		pr_err("Kernel doesn't support dirty tracking. "
-				"No snapshot available.\n");
-		return ERR_PTR(-1);
-	}
-
 	p_fd = get_service_fd(PARENT_FD_OFF);
 	if (p_fd < 0) {
 		pr_debug("Will do full memory dump\n");

test/mem-snap/run.sh

@@ -40,13 +40,13 @@ for SNAP in $(seq 1 $NRSNAP); do
 	mkdir "$IMGDIR/$SNAP/"
 	if [ $SNAP -eq 1 ] ; then
 		# First snapshot -- no parent, keep running
-		args="--snapshot -R"
+		args="--track-mem -R"
 	elif [ $SNAP -eq $NRSNAP ]; then
 		# Last snapshot -- has parent, kill afterwards
-		args="--snapshot=../$((SNAP - 1))/"
+		args="--prev-images-dir=../$((SNAP - 1))/"
 	else
 		# Other snapshots -- have parent, keep running
-		args="--snapshot=../$((SNAP - 1))/ -R"
+		args="--prev-images-dir=../$((SNAP - 1))/ --track-mem -R"
 	fi
 
 	if [ $USEPS -eq 1 ]; then