[Qemu-devel] [v3 11/13] migration: Add interface to control compression

[Liang Li <liang.z.li@intel.com>]

The multiple compression threads can be turned on/off through
qmp and hmp interface when doing live migration.

Signed-off-by: Liang Li <liang.z.li@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
---
 migration.c      | 7 +++++--
 qapi-schema.json | 6 +++++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/migration.c b/migration.c
index 082ddb7..9d1613d 100644
--- a/migration.c
+++ b/migration.c
@@ -576,8 +576,11 @@ bool migrate_zero_blocks(void)
 
 bool migrate_use_compression(void)
 {
-    /* Disable compression before the series of patches are applied */
-    return false;
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS];
 }
 
 int migrate_compress_level(void)
diff --git a/qapi-schema.json b/qapi-schema.json
index 9ffdcf8..d371af3 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -491,13 +491,17 @@
 #          to enable the capability on the source VM. The feature is disabled by
 #          default. (since 1.6)
 #
+# @compress: Using the multiple compression threads to accelerate live migration.
+#          This feature can help to reduce the migration traffic, by sending
+#          compressed pages. The feature is disabled by default. (since 2.3)
+#
 # @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', 'rdma-pin-all', 'auto-converge', 'zero-blocks'] }
+  'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks', 'compress'] }
 
 ##
 # @MigrationCapabilityStatus
-- 
1.8.3.1