[PATCH v4 4/7] migration/multifd: Enable multifd zero page checking by default.

[Hao Xiang <hao.xiang@bytedance.com>]

Set default "zero-page-detection" option to "multifd". Now zero page
checking can be done in the multifd threads and this becomes the
default configuration. We still provide backward compatibility
where zero page checking is done from the migration main thread.

Signed-off-by: Hao Xiang <hao.xiang@bytedance.com>
---
 migration/options.c | 2 +-
 qapi/migration.json | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/migration/options.c b/migration/options.c
index 3c603391b0..3c79b6ccd4 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -181,7 +181,7 @@ Property migration_properties[] = {
                       MIG_MODE_NORMAL),
     DEFINE_PROP_ZERO_PAGE_DETECTION("zero-page-detection", MigrationState,
                        parameters.zero_page_detection,
-                       ZERO_PAGE_DETECTION_LEGACY),
+                       ZERO_PAGE_DETECTION_MULTIFD),
 
     /* Migration capabilities */
     DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
diff --git a/qapi/migration.json b/qapi/migration.json
index 846d0411d5..ca9561fbf1 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -903,7 +903,7 @@
 #        (Since 8.2)
 #
 # @zero-page-detection: Whether and how to detect zero pages.
-#     See description in @ZeroPageDetection.  Default is 'legacy'.
+#     See description in @ZeroPageDetection.  Default is 'multifd'.
 #     (since 9.0)
 #
 # Features:
@@ -1100,7 +1100,7 @@
 #        (Since 8.2)
 #
 # @zero-page-detection: Whether and how to detect zero pages.
-#     See description in @ZeroPageDetection.  Default is 'legacy'.
+#     See description in @ZeroPageDetection.  Default is 'multifd'.
 #     (since 9.0)
 #
 # Features:
@@ -1333,7 +1333,7 @@
 #        (Since 8.2)
 #
 # @zero-page-detection: Whether and how to detect zero pages.
-#     See description in @ZeroPageDetection.  Default is 'legacy'.
+#     See description in @ZeroPageDetection.  Default is 'multifd'.
 #     (since 9.0)
 #
 # Features:
-- 
2.30.2