[Qemu-devel] [PATCH 4/6] Migration: Emit event at start of pass

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <address@hidden>

Emit an event each time we sync the dirty bitmap on the source;
this helps libvirt use postcopy by giving it a kick when it
might be a good idea to start the postcopy.

Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
 migration/ram.c |  4 ++++
 qapi/event.json | 11 +++++++++++
 2 files changed, 15 insertions(+)

diff --git a/migration/ram.c b/migration/ram.c
index 0490f00..102d1f2 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -27,6 +27,7 @@
  */
 #include <stdint.h>
 #include <zlib.h>
+#include "qapi-event.h"
 #include "qemu/bitops.h"
 #include "qemu/bitmap.h"
 #include "qemu/timer.h"
@@ -682,6 +683,9 @@ static void migration_bitmap_sync(void)
         num_dirty_pages_period = 0;
     }
     s->dirty_sync_count = bitmap_sync_count;
+    if (migrate_use_events()) {
+        qapi_event_send_migration_pass(bitmap_sync_count, NULL);
+    }
 }
 
 /**
diff --git a/qapi/event.json b/qapi/event.json
index f0cef01..2440dbc 100644
--- a/qapi/event.json
+++ b/qapi/event.json
@@ -255,6 +255,17 @@
   'data': {'status': 'MigrationStatus'}}
 
 ##
+# @MIGRATION_PASS
+#
+# Emitted from the source side of a migration at the start of each pass
+# (when it syncs the dirty bitmap)
+#
+# Since: 2.6
+##
+{ 'event': 'MIGRATION_PASS',
+  'data': { 'pass': 'int' } }
+
+##
 # @ACPI_DEVICE_OST
 #
 # Emitted when guest executes ACPI _OST method.
-- 
2.5.0