migration: do not wait for free thread

Instead of putting the main thread to sleep state to wait for
free compression thread, we can directly post it out as normal
page that reduces the latency and uses CPUs more efficiently

A parameter, compress-wait-thread, is introduced, it can be
enabled if the user really wants the old behavior

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/hmp.c b/hmp.c
index c38e8b1f78..9147037951 100644
--- a/hmp.c
+++ b/hmp.c
@@ -327,6 +327,10 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
         monitor_printf(mon, "%s: %u\n",
             MigrationParameter_str(MIGRATION_PARAMETER_COMPRESS_THREADS),
             params->compress_threads);
+        assert(params->has_compress_wait_thread);
+        monitor_printf(mon, "%s: %s\n",
+            MigrationParameter_str(MIGRATION_PARAMETER_COMPRESS_WAIT_THREAD),
+            params->compress_wait_thread ? "on" : "off");
         assert(params->has_decompress_threads);
         monitor_printf(mon, "%s: %u\n",
             MigrationParameter_str(MIGRATION_PARAMETER_DECOMPRESS_THREADS),
@@ -1627,6 +1631,10 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
         p->has_compress_threads = true;
         visit_type_int(v, param, &p->compress_threads, &err);
         break;
+    case MIGRATION_PARAMETER_COMPRESS_WAIT_THREAD:
+        p->has_compress_wait_thread = true;
+        visit_type_bool(v, param, &p->compress_wait_thread, &err);
+        break;
     case MIGRATION_PARAMETER_DECOMPRESS_THREADS:
         p->has_decompress_threads = true;
         visit_type_int(v, param, &p->decompress_threads, &err);