[PATCH RFCv1 3/8] migration: Add last stage indicator to global dirty log synchronization

[Gavin Shan]

For the pre-copy live migration scenario, the last stage indicator
is needed for KVM backend to collect the dirty pages from the backup
bitmap when dirty ring is used. The indicator isn't used so far.

No functional change intended.

Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 migration/ram.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index d1b9b270ec..6c9642edee 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1176,7 +1176,7 @@ static void migration_trigger_throttle(RAMState *rs)
     }
 }
 
-static void migration_bitmap_sync(RAMState *rs)
+static void migration_bitmap_sync(RAMState *rs, bool last_stage)
 {
     RAMBlock *block;
     int64_t end_time;
@@ -1188,7 +1188,7 @@ static void migration_bitmap_sync(RAMState *rs)
     }
 
     trace_migration_bitmap_sync_start();
-    memory_global_dirty_log_sync(false);
+    memory_global_dirty_log_sync(last_stage);
 
     qemu_mutex_lock(&rs->bitmap_mutex);
     WITH_RCU_READ_LOCK_GUARD() {
@@ -1222,7 +1222,7 @@ static void migration_bitmap_sync(RAMState *rs)
     }
 }
 
-static void migration_bitmap_sync_precopy(RAMState *rs)
+static void migration_bitmap_sync_precopy(RAMState *rs, bool last_stage)
 {
     Error *local_err = NULL;
 
@@ -1235,7 +1235,7 @@ static void migration_bitmap_sync_precopy(RAMState *rs)
         local_err = NULL;
     }
 
-    migration_bitmap_sync(rs);
+    migration_bitmap_sync(rs, last_stage);
 
     if (precopy_notify(PRECOPY_NOTIFY_AFTER_BITMAP_SYNC, &local_err)) {
         error_report_err(local_err);
@@ -2844,7 +2844,7 @@ void ram_postcopy_send_discard_bitmap(MigrationState *ms)
     RCU_READ_LOCK_GUARD();
 
     /* This should be our last sync, the src is now paused */
-    migration_bitmap_sync(rs);
+    migration_bitmap_sync(rs, false);
 
     /* Easiest way to make sure we don't resume in the middle of a host-page */
     rs->pss[RAM_CHANNEL_PRECOPY].last_sent_block = NULL;
@@ -3034,7 +3034,7 @@ static void ram_init_bitmaps(RAMState *rs)
         /* We don't use dirty log with background snapshots */
         if (!migrate_background_snapshot()) {
             memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION);
-            migration_bitmap_sync_precopy(rs);
+            migration_bitmap_sync_precopy(rs, false);
         }
     }
     qemu_mutex_unlock_ramlist();
@@ -3349,7 +3349,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
 
     WITH_RCU_READ_LOCK_GUARD() {
         if (!migration_in_postcopy()) {
-            migration_bitmap_sync_precopy(rs);
+            migration_bitmap_sync_precopy(rs, true);
         }
 
         ram_control_before_iterate(f, RAM_CONTROL_FINISH);
@@ -3407,7 +3407,7 @@ static void ram_save_pending(QEMUFile *f, void *opaque, 
uint64_t max_size,
         remaining_size < max_size) {
         qemu_mutex_lock_iothread();
         WITH_RCU_READ_LOCK_GUARD() {
-            migration_bitmap_sync_precopy(rs);
+            migration_bitmap_sync_precopy(rs, false);
         }
         qemu_mutex_unlock_iothread();
         remaining_size = rs->migration_dirty_pages * TARGET_PAGE_SIZE;
-- 
2.23.0