[Qemu-devel] [RFC PATCH v4 04/28] migration: Integrate COLO checkpoint process into migration

[zhanghailiang <zhang.zhanghailiang@huawei.com>]

Add a migrate state: MIGRATION_STATUS_COLO, enter this migration state
after the first live migration successfully finished.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
 include/migration/migration-colo.h |  3 ++
 include/migration/migration.h      |  2 ++
 migration/colo.c                   | 65 ++++++++++++++++++++++++++++++++++++++
 migration/migration.c              | 22 ++++++++++---
 qapi-schema.json                   |  2 +-
 stubs/migration-colo.c             |  9 ++++++
 6 files changed, 97 insertions(+), 6 deletions(-)

diff --git a/include/migration/migration-colo.h b/include/migration/migration-colo.h
index de68c72..cac23e1 100644
--- a/include/migration/migration-colo.h
+++ b/include/migration/migration-colo.h
@@ -19,4 +19,7 @@
 bool colo_supported(void);
 void colo_info_mig_init(void);
 
+void colo_init_checkpointer(MigrationState *s);
+bool migrate_in_colo_state(void);
+
 #endif
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 59acb62..c723a02 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -65,6 +65,8 @@ struct MigrationState
     int64_t dirty_sync_count;
 };
 
+void migrate_set_state(MigrationState *s, int old_state, int new_state);
+
 void process_incoming_migration(QEMUFile *f);
 
 void qemu_start_incoming_migration(const char *uri, Error **errp);
diff --git a/migration/colo.c b/migration/colo.c
index babfe4f..d8cab6d 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -10,9 +10,74 @@
  * later.  See the COPYING file in the top-level directory.
  */
 
+#include "sysemu/sysemu.h"
 #include "migration/migration-colo.h"
+#include "qemu/error-report.h"
+
+#define DEBUG_COLO 0
+
+#define DPRINTF(fmt, ...)                                   \
+    do {                                                    \
+        if (DEBUG_COLO) {                                   \
+            fprintf(stderr, "colo: " fmt , ## __VA_ARGS__); \
+        }                                                   \
+    } while (0)
+
+static QEMUBH *colo_bh;
 
 bool colo_supported(void)
 {
     return true;
 }
+
+bool migrate_in_colo_state(void)
+{
+    MigrationState *s = migrate_get_current();
+    return (s->state == MIGRATION_STATUS_COLO);
+}
+
+static void *colo_thread(void *opaque)
+{
+    MigrationState *s = opaque;
+
+    qemu_mutex_lock_iothread();
+    vm_start();
+    qemu_mutex_unlock_iothread();
+    DPRINTF("vm resume to run\n");
+
+
+    /*TODO: COLO checkpoint savevm loop*/
+
+    migrate_set_state(s, MIGRATION_STATUS_COLO, MIGRATION_STATUS_COMPLETED);
+
+    qemu_mutex_lock_iothread();
+    qemu_bh_schedule(s->cleanup_bh);
+    qemu_mutex_unlock_iothread();
+
+    return NULL;
+}
+
+static void colo_start_checkpointer(void *opaque)
+{
+    MigrationState *s = opaque;
+
+    if (colo_bh) {
+        qemu_bh_delete(colo_bh);
+        colo_bh = NULL;
+    }
+
+    qemu_mutex_unlock_iothread();
+    qemu_thread_join(&s->thread);
+    qemu_mutex_lock_iothread();
+
+    migrate_set_state(s, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_COLO);
+
+    qemu_thread_create(&s->thread, "colo", colo_thread, s,
+                       QEMU_THREAD_JOINABLE);
+}
+
+void colo_init_checkpointer(MigrationState *s)
+{
+    colo_bh = qemu_bh_new(colo_start_checkpointer, s);
+    qemu_bh_schedule(colo_bh);
+}
diff --git a/migration/migration.c b/migration/migration.c
index 7009ddd..d904c4d 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -235,6 +235,10 @@ MigrationInfo *qmp_query_migrate(Error **errp)
 
         get_xbzrle_cache_stats(info);
         break;
+    case MIGRATION_STATUS_COLO:
+        info->has_status = true;
+        /* TODO: display COLO specific information (checkpoint info etc.) */
+        break;
     case MIGRATION_STATUS_COMPLETED:
         get_xbzrle_cache_stats(info);
 
@@ -296,7 +300,7 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
 
 /* shared migration helpers */
 
-static void migrate_set_state(MigrationState *s, int old_state, int new_state)
+void migrate_set_state(MigrationState *s, int old_state, int new_state)
 {
     if (atomic_cmpxchg(&s->state, old_state, new_state) == new_state) {
         trace_migrate_set_state(new_state);
@@ -633,6 +637,7 @@ static void *migration_thread(void *opaque)
     int64_t max_size = 0;
     int64_t start_time = initial_time;
     bool old_vm_running = false;
+    bool enable_colo = migrate_enable_colo();
 
     qemu_savevm_state_begin(s->file, &s->params);
 
@@ -670,8 +675,10 @@ static void *migration_thread(void *opaque)
                 }
 
                 if (!qemu_file_get_error(s->file)) {
-                    migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
-                                      MIGRATION_STATUS_COMPLETED);
+                    if (!enable_colo) {
+                        migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
+                                          MIGRATION_STATUS_COMPLETED);
+                    }
                     break;
                 }
             }
@@ -722,11 +729,16 @@ static void *migration_thread(void *opaque)
         }
         runstate_set(RUN_STATE_POSTMIGRATE);
     } else {
-        if (old_vm_running) {
+        if (s->state == MIGRATION_STATUS_ACTIVE && enable_colo) {
+            colo_init_checkpointer(s);
+        } else if (old_vm_running) {
             vm_start();
         }
     }
-    qemu_bh_schedule(s->cleanup_bh);
+
+    if (!enable_colo) {
+        qemu_bh_schedule(s->cleanup_bh);
+    }
     qemu_mutex_unlock_iothread();
 
     return NULL;
diff --git a/qapi-schema.json b/qapi-schema.json
index 193cad4..172aae3 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -433,7 +433,7 @@
 ##
 { 'enum': 'MigrationStatus',
   'data': [ 'none', 'setup', 'cancelling', 'cancelled',
-            'active', 'completed', 'failed' ] }
+            'active', 'completed', 'failed', 'colo' ] }
 
 ##
 # @MigrationInfo
diff --git a/stubs/migration-colo.c b/stubs/migration-colo.c
index ccbaea8..495ca28 100644
--- a/stubs/migration-colo.c
+++ b/stubs/migration-colo.c
@@ -16,3 +16,12 @@ bool colo_supported(void)
 {
     return false;
 }
+
+bool migrate_in_colo_state(void)
+{
+    return false;
+}
+
+void colo_init_checkpointer(MigrationState *s)
+{
+}
-- 
1.7.12.4