[Qemu-devel] [PATCH 17/18] ram: Use memory_region_test_and_clear_dirty

[Juan Quintela <quintela@redhat.com>]

This avoids having to do two walks over the dirty bitmap, one reading
the dirty bits, and another cleaning them.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 arch_init.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index 1eefef8..79f466f 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -385,13 +385,12 @@ static void migration_bitmap_sync(void)

     QLIST_FOREACH(block, &ram_list.blocks, next) {
         for (addr = 0; addr < block->length; addr += TARGET_PAGE_SIZE) {
-            if (memory_region_get_dirty(block->mr, addr, TARGET_PAGE_SIZE,
-                                        DIRTY_MEMORY_MIGRATION)) {
+            if (memory_region_test_and_clear_dirty(block->mr,
+                                                   addr, TARGET_PAGE_SIZE,
+                                                   DIRTY_MEMORY_MIGRATION)) {
                 migration_bitmap_set_dirty(block->mr, addr);
             }
         }
-        memory_region_reset_dirty(block->mr, 0, block->length,
-                                  DIRTY_MEMORY_MIGRATION);
     }
     trace_migration_bitmap_sync_end(migration_dirty_pages
                                     - num_dirty_pages_init);
-- 
1.7.11.7