migration: do not search dirty pages in bulk stage

avoid searching for dirty pages just increment the
page offset. all pages are dirty anyway.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/arch_init.c b/arch_init.c
index 3a0d02eafa..a522735dd1 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -340,7 +340,13 @@ ram_addr_t migration_bitmap_find_and_reset_dirty(MemoryRegion *mr,
     unsigned long nr = base + (start >> TARGET_PAGE_BITS);
     unsigned long size = base + (int128_get64(mr->size) >> TARGET_PAGE_BITS);
 
-    unsigned long next = find_next_bit(migration_bitmap, size, nr);
+    unsigned long next;
+
+    if (ram_bulk_stage && nr > base) {
+        next = nr + 1;
+    } else {
+        next = find_next_bit(migration_bitmap, size, nr);
+    }
 
     if (next < size) {
         clear_bit(next, migration_bitmap);