[Qemu-devel] [PATCH 07/27] ram: Introduce migration_bitmap_test_and_reset_dirty()

[Juan Quintela <quintela@redhat.com>]

It just test if the dirty bit is set, and clears it.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 arch_init.c |   19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index b47bf05..c49c321 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -342,6 +342,19 @@ static RAMBlock *last_block;
 static ram_addr_t last_offset;
 static uint32_t last_version;

+static inline bool migration_bitmap_test_and_reset_dirty(MemoryRegion *mr,
+                                                         ram_addr_t offset)
+{
+    bool ret = memory_region_get_dirty(mr, offset, TARGET_PAGE_SIZE,
+                                       DIRTY_MEMORY_MIGRATION);
+
+    if (ret) {
+        memory_region_reset_dirty(mr, offset, TARGET_PAGE_SIZE,
+                                  DIRTY_MEMORY_MIGRATION);
+    }
+    return ret;
+}
+
 static inline void migration_bitmap_set_dirty(MemoryRegion *mr, int length)
 {
     ram_addr_t addr;
@@ -375,14 +388,10 @@ static int ram_save_block(QEMUFile *f, bool last_stage)

     do {
         mr = block->mr;
-        if (memory_region_get_dirty(mr, offset, TARGET_PAGE_SIZE,
-                                    DIRTY_MEMORY_MIGRATION)) {
+        if (migration_bitmap_test_and_reset_dirty(mr, offset)) {
             uint8_t *p;
             int cont = (block == last_block) ? RAM_SAVE_FLAG_CONTINUE : 0;

-            memory_region_reset_dirty(mr, offset, TARGET_PAGE_SIZE,
-                                      DIRTY_MEMORY_MIGRATION);
-
             p = memory_region_get_ram_ptr(mr) + offset;

             if (is_dup_page(p)) {
-- 
1.7.10.4