[Qemu-devel] [PATCH v8 2/3] Add 'auto-converge' migration capability

[Chegu Vinod <chegu_vinod@hp.com>]

The auto-converge migration capability allows the user to specify if they
choose live migration seqeunce to automatically detect and force convergence.

Signed-off-by: Chegu Vinod <chegu_vinod@hp.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/migration/migration.h |    2 ++
 migration.c                   |    9 +++++++++
 qapi-schema.json              |    5 ++++-
 3 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/include/migration/migration.h b/include/migration/migration.h
index e2acec6..ace91b0 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -127,4 +127,6 @@ int migrate_use_xbzrle(void);
 int64_t migrate_xbzrle_cache_size(void);
 
 int64_t xbzrle_cache_resize(int64_t new_size);
+
+bool migrate_auto_converge(void);
 #endif
diff --git a/migration.c b/migration.c
index 058f9e6..d0759c1 100644
--- a/migration.c
+++ b/migration.c
@@ -473,6 +473,15 @@ void qmp_migrate_set_downtime(double value, Error **errp)
     max_downtime = (uint64_t)value;
 }
 
+bool migrate_auto_converge(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
+}
+
 int migrate_use_xbzrle(void)
 {
     MigrationState *s;
diff --git a/qapi-schema.json b/qapi-schema.json
index a80ee40..c019fec 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -605,10 +605,13 @@
 #          This feature allows us to minimize migration traffic for certain work
 #          loads, by sending compressed difference of the pages
 #
+# @auto-converge: If enabled, QEMU will automatically throttle down the guest
+#          to speed up convergence of RAM migration. (since 1.6)
+#
 # Since: 1.2
 ##
 { 'enum': 'MigrationCapability',
-  'data': ['xbzrle'] }
+  'data': ['xbzrle', 'auto-converge'] }
 
 ##
 # @MigrationCapabilityStatus
-- 
1.7.1