stats: Prepare for collecting restore stats

Restore stats are difficult -- we have to collect them from several
tasks and thus existing plain variables would not work. We'll need
shared memory with stats, so prepre for allocating one.

Other than this -- put call to write_stats() where appropriate for
restore.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -1593,6 +1593,9 @@ int cr_pre_dump_tasks(pid_t pid)
 	LIST_HEAD(ctls);
 	struct parasite_ctl *ctl, *n;
 
+	if (init_stats(DUMP_STATS))
+		goto err;
+
 	if (kerndat_init())
 		goto err;
 
@@ -1657,6 +1660,9 @@ int cr_dump_tasks(pid_t pid)
 	pr_info("Dumping processes (pid: %d)\n", pid);
 	pr_info("========================================\n");
 
+	if (init_stats(DUMP_STATS))
+		goto err;
+
 	if (kerndat_init())
 		goto err;
 

cr-restore.c

@@ -60,6 +60,7 @@
 #include "page-read.h"
 #include "sysctl.h"
 #include "vdso.h"
+#include "stats.h"
 
 #include "protobuf.h"
 #include "protobuf/sa.pb-c.h"
@@ -1360,6 +1361,8 @@ out:
 	pr_info("Restore finished successfully. Resuming tasks.\n");
 	futex_set_and_wake(&task_entries->start, CR_STATE_COMPLETE);
 
+	write_stats(RESTORE_STATS);
+
 	if (!opts.restore_detach)
 		wait(NULL);
 	return 0;
@@ -1386,6 +1389,9 @@ int cr_restore_tasks(void)
 	if (check_img_inventory() < 0)
 		return -1;
 
+	if (init_stats(RESTORE_STATS))
+		return -1;
+
 	if (cpu_init() < 0)
 		return -1;
 

include/stats.h

@@ -25,6 +25,9 @@ enum {
 void cnt_add(int c, unsigned long val);
 
 #define DUMP_STATS	1
+#define RESTORE_STATS	2
+
+int init_stats(int what);
 void write_stats(int what);
 
 #endif

stats.c

@@ -93,3 +93,11 @@ void write_stats(int what)
 		close(fd);
 	}
 }
+
+int init_stats(int what)
+{
+	if (what == DUMP_STATS)
+		return 0;
+
+	return 0;
+}