mem/stats: Add stats about memory dumping

pages_scanned -- the amount of pages criu looked at for decision
pages_skipped_parent -- the amount of pages that were skipped, due to
                        they are present in parent image
pages_writted -- the amount of pages criu transfered into image
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/stats.h

@@ -14,6 +14,16 @@ enum {
 void timing_start(int t);
 void timing_stop(int t);
 
+enum {
+	CNT_PAGES_SCANNED,
+	CNT_PAGES_SKIPPED_PARENT,
+	CNT_PAGES_WRITTEN,
+
+	CNT_NR_STATS,
+};
+
+void cnt_add(int c, unsigned long val);
+
 #define DUMP_STATS	1
 void write_stats(int what);
 

mem.c

@@ -251,6 +251,10 @@ static int generate_iovs(struct vma_area *vma, int pagemap, struct page_pipe *pp
 			return -1;
 	}
 
+	cnt_add(CNT_PAGES_SCANNED, nr_to_scan);
+	cnt_add(CNT_PAGES_SKIPPED_PARENT, pages[0]);
+	cnt_add(CNT_PAGES_WRITTEN, pages[1]);
+
 	pr_info("Pagemap generated: %lu pages %lu holes\n", pages[1], pages[0]);
 	return 0;
 }

protobuf/stats.proto

@@ -4,6 +4,10 @@ message dump_stats_entry {
 	required uint32 frozen_time = 2;
 	required uint32 memdump_time = 3;
 	required uint32	memwrite_time = 4;
+
+	required uint64	pages_scanned = 5;
+	required uint64	pages_skipped_parent = 6;
+	required uint64	pages_written = 7;
 }
 
 message stats_entry {

stats.c

@@ -12,6 +12,14 @@ struct timing {
 
 static struct timing timings[TIME_NR_STATS];
 
+static unsigned long counts[CNT_NR_STATS];
+
+void cnt_add(int c, unsigned long val)
+{
+	BUG_ON(c >= CNT_NR_STATS);
+	counts[c] += val;
+}
+
 static void timeval_accumulate(const struct timeval *from, const struct timeval *to,
 		struct timeval *res)
 {
@@ -46,7 +54,8 @@ void timing_stop(int t)
 
 void show_stats(int fd)
 {
-	do_pb_show_plain(fd, PB_STATS, 1, NULL, "1.1:%u 1.2:%u 1.3:%u 1.4:%u");
+	do_pb_show_plain(fd, PB_STATS, 1, NULL,
+			"1.1:%u 1.2:%u 1.3:%u 1.4:%u 1.5:%Lu 1.6:%Lu 1.7:%Lu");
 }
 
 static void encode_time(int t, u_int32_t *to)
@@ -70,6 +79,10 @@ void write_stats(int what)
 		encode_time(TIME_MEMDUMP, &dstats.memdump_time);
 		encode_time(TIME_MEMWRITE, &dstats.memwrite_time);
 
+		dstats.pages_scanned = counts[CNT_PAGES_SCANNED];
+		dstats.pages_skipped_parent = counts[CNT_PAGES_SKIPPED_PARENT];
+		dstats.pages_written = counts[CNT_PAGES_WRITTEN];
+
 		name = "dump";
 	} else
 		return;