[Qemu-devel] [RFC PATCH v2 12/12] mc: activate and use MC if requested

[mrhines@linux.vnet.ibm.com]

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

Once the initial migration has completed, we kickoff the migration_thread,
which never dies. Additionally, we register load/save functions for MC
which allow us to inform the destination that we are requesting a
micro-checkpointing session without needing to add additional command-line
switches on the destination side.

Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>
---
 include/migration/migration.h |  2 +-
 include/migration/qemu-file.h |  1 +
 migration.c                   | 33 ++++++++++++++++++++++++++++-----
 vl.c                          |  2 ++
 4 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/include/migration/migration.h b/include/migration/migration.h
index f18ff5e..1695e9e 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -46,7 +46,7 @@ struct MigrationState
     int64_t bandwidth_limit;
     size_t bytes_xfer;
     size_t xfer_limit;
-    QemuThread thread;
+    QemuThread *thread;
     QEMUBH *cleanup_bh;
     QEMUFile *file;
 
diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
index c50de0d..89e7c19 100644
--- a/include/migration/qemu-file.h
+++ b/include/migration/qemu-file.h
@@ -148,6 +148,7 @@ QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
 QEMUFile *qemu_fopen(const char *filename, const char *mode);
 QEMUFile *qemu_fdopen(int fd, const char *mode);
 QEMUFile *qemu_fopen_socket(int fd, const char *mode);
+QEMUFile *qemu_fopen_mc(void *opaque, const char *mode);
 QEMUFile *qemu_popen_cmd(const char *command, const char *mode);
 int qemu_get_fd(QEMUFile *f);
 int qemu_fclose(QEMUFile *f);
diff --git a/migration.c b/migration.c
index 0ccbeaa..1a6fdbd 100644
--- a/migration.c
+++ b/migration.c
@@ -93,6 +93,9 @@ static void process_incoming_migration_co(void *opaque)
     int ret;
 
     ret = qemu_loadvm_state(f);
+    if (ret >= 0) {
+        mc_process_incoming_checkpoints_if_requested(f);
+    }
     qemu_fclose(f);
     free_xbzrle_decoded_buf();
     if (ret < 0) {
@@ -313,14 +316,17 @@ static void migrate_fd_cleanup(void *opaque)
 {
     MigrationState *s = opaque;
 
-    qemu_bh_delete(s->cleanup_bh);
-    s->cleanup_bh = NULL;
+    if(s->cleanup_bh) {
+        qemu_bh_delete(s->cleanup_bh);
+        s->cleanup_bh = NULL;
+    }
 
     if (s->file) {
         DPRINTF("closing file\n");
         qemu_mutex_unlock_iothread();
-        qemu_thread_join(&s->thread);
+        qemu_thread_join(s->thread);
         qemu_mutex_lock_iothread();
+        g_free(s->thread);
 
         qemu_fclose(s->file);
         s->file = NULL;
@@ -695,11 +701,27 @@ static void *migration_thread(void *opaque)
         s->downtime = end_time - start_time;
         runstate_set(RUN_STATE_POSTMIGRATE);
     } else {
+        if(migrate_use_mc()) {
+            qemu_fflush(s->file);
+            if (migrate_use_mc_net()) {
+                if (mc_enable_buffering() < 0 ||
+                        mc_start_buffer() < 0) {
+                    migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
+                }
+            }
+        }
+
         if (old_vm_running) {
             vm_start();
         }
     }
-    qemu_bh_schedule(s->cleanup_bh);
+
+    if (migrate_use_mc() && s->state != MIG_STATE_ERROR) {
+        mc_init_checkpointer(s);
+    } else {
+        qemu_bh_schedule(s->cleanup_bh);
+    }
+
     qemu_mutex_unlock_iothread();
 
     return NULL;
@@ -720,6 +742,7 @@ void migrate_fd_connect(MigrationState *s)
     /* Notify before starting migration thread */
     notifier_list_notify(&migration_state_notifiers, s);
 
-    qemu_thread_create(&s->thread, migration_thread, s,
+    s->thread = g_malloc0(sizeof(*s->thread));
+    qemu_thread_create(s->thread, migration_thread, s,
                        QEMU_THREAD_JOINABLE);
 }
diff --git a/vl.c b/vl.c
index 2fb5b1f..093eb20 100644
--- a/vl.c
+++ b/vl.c
@@ -4145,6 +4145,8 @@ int main(int argc, char **argv, char **envp)
     default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
 
     register_savevm_live(NULL, "ram", 0, 4, &savevm_ram_handlers, NULL);
+    register_savevm(NULL, "mc", -1, MC_VERSION, mc_info_save, 
+                                mc_info_load, NULL); 
 
     if (nb_numa_nodes > 0) {
         int i;
-- 
1.8.1.2