stats: drop zero pages stats

Note, that since zero pages stats never been into master we can make
incompatible changes to stats image.

travis-ci: success for revert zero pagemaps
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/include/stats.h

@@ -25,7 +25,6 @@ enum {
 	CNT_PAGES_SCANNED,
 	CNT_PAGES_SKIPPED_PARENT,
 	CNT_PAGES_WRITTEN,
-	CNT_PAGES_ZERO,
 	CNT_PAGES_LAZY,
 
 	DUMP_CNT_NR_STATS,

criu/stats.c

@@ -120,8 +120,6 @@ static void display_stats(int what, StatsEntry *stats)
 				stats->dump->pages_skipped_parent);
 		pr_msg("Memory pages written: %" PRIu64 " (0x%" PRIx64 ")\n", stats->dump->pages_written,
 				stats->dump->pages_written);
-		pr_msg("Zero memory pages: %" PRIu64 " (0x%" PRIx64 ")\n", stats->dump->pages_zero,
-				stats->dump->pages_zero);
 		pr_msg("Lazy memory pages: %" PRIu64 " (0x%" PRIx64 ")\n", stats->dump->pages_lazy,
 				stats->dump->pages_lazy);
 	} else if (what == RESTORE_STATS) {
@@ -161,7 +159,6 @@ void write_stats(int what)
 		ds_entry.pages_scanned = dstats->counts[CNT_PAGES_SCANNED];
 		ds_entry.pages_skipped_parent = dstats->counts[CNT_PAGES_SKIPPED_PARENT];
 		ds_entry.pages_written = dstats->counts[CNT_PAGES_WRITTEN];
-		ds_entry.pages_zero = dstats->counts[CNT_PAGES_ZERO];
 		ds_entry.pages_lazy = dstats->counts[CNT_PAGES_LAZY];
 
 		name = "dump";

images/stats.proto

@@ -13,8 +13,7 @@ message dump_stats_entry {
 
 	optional uint32			irmap_resolve		= 8;
 
-	required uint64			pages_zero		= 9;
-	required uint64			pages_lazy		= 10;
+	required uint64			pages_lazy		= 9;
 }
 
 message restore_stats_entry {