[Qemu-devel] [PATCH V6 05/10] migration: introduce postcopy-blocktime capability

[Alexey Perevalov]

Right now it could be used on destination side to
enable vCPU blocktime calculation for postcopy live migration.
vCPU blocktime - it's time since vCPU thread was put into
interruptible sleep, till memory page was copied and thread awake.

Reviewed-by: Dr. David Alan Gilbert <address@hidden>
Signed-off-by: Alexey Perevalov <address@hidden>
---
 include/migration/migration.h | 1 +
 migration/migration.c         | 9 +++++++++
 qapi-schema.json              | 5 ++++-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/migration/migration.h b/include/migration/migration.h
index 49ec501..2951253 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -270,6 +270,7 @@ int migrate_compress_level(void);
 int migrate_compress_threads(void);
 int migrate_decompress_threads(void);
 bool migrate_use_events(void);
+bool migrate_postcopy_blocktime(void);
 
 /* Sending on the return path - generic and then for each message type */
 void migrate_send_rp_message(MigrationIncomingState *mis,
diff --git a/migration/migration.c b/migration/migration.c
index d735976..e10284e 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1341,6 +1341,15 @@ bool migrate_zero_blocks(void)
     return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
 }
 
+bool migrate_postcopy_blocktime(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME];
+}
+
 bool migrate_use_compression(void)
 {
     MigrationState *s;
diff --git a/qapi-schema.json b/qapi-schema.json
index 80603cf..78617fe 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -894,11 +894,14 @@
 # @release-ram: if enabled, qemu will free the migrated ram pages on the source
 #        during postcopy-ram migration. (since 2.9)
 #
+# @postcopy-blocktime: Calculate downtime for postcopy live migration (since 
2.10)
+#
 # Since: 1.2
 ##
 { 'enum': 'MigrationCapability',
   'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
-           'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram'] }
+           'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram',
+           'postcopy-blocktime'] }
 
 ##
 # @MigrationCapabilityStatus:
-- 
1.8.3.1