[Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration

[mrhines@linux.vnet.ibm.com]

From: "Michael R. Hines" <mrhines@us.ibm.com>

This capability allows you to disable dynamic chunk registration
for better throughput on high-performance links.

It is enabled by default.

Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>
---
 migration.c      |   10 ++++++++++
 qapi-schema.json |    8 +++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/migration.c b/migration.c
index 3b4b467..5afd9b8 100644
--- a/migration.c
+++ b/migration.c
@@ -66,6 +66,7 @@ MigrationState *migrate_get_current(void)
         .state = MIG_STATE_SETUP,
         .bandwidth_limit = MAX_THROTTLE,
         .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
+        .enabled_capabilities[MIGRATION_CAPABILITY_X_CHUNK_REGISTER_DESTINATION] = true,
     };
 
     return &current_migration;
@@ -474,6 +475,15 @@ void qmp_migrate_set_downtime(double value, Error **errp)
     max_downtime = (uint64_t)value;
 }
 
+bool migrate_chunk_register_destination(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->enabled_capabilities[MIGRATION_CAPABILITY_X_CHUNK_REGISTER_DESTINATION];
+}
+
 int migrate_use_xbzrle(void)
 {
     MigrationState *s;
diff --git a/qapi-schema.json b/qapi-schema.json
index 751d3c2..297707e 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -599,10 +599,16 @@
 #          This feature allows us to minimize migration traffic for certain work
 #          loads, by sending compressed difference of the pages
 #
+# @x-chunk-register-destination: (since 1.5) RDMA option which controls whether
+#          or not the entire VM memory footprint is mlock() on demand or all at once.
+#          Refer to docs/rdma.txt for more advice on when to take advantage option.
+#          Enabled by default, and will be renamed to 'chunk-register-destination' 
+#          after experimental testing is complete.
+#
 # Since: 1.2
 ##
 { 'enum': 'MigrationCapability',
-  'data': ['xbzrle'] }
+  'data': ['xbzrle', 'x-chunk-register-destination'] }
 
 ##
 # @MigrationCapabilityStatus
-- 
1.7.10.4