diff options
| -rw-r--r-- | include/migration/migration.h | 3 | ||||
| -rw-r--r-- | migration/migration.c | 174 | ||||
| -rw-r--r-- | trace-events | 4 |
3 files changed, 174 insertions, 7 deletions
diff --git a/include/migration/migration.h b/include/migration/migration.h index 2ad0d2b9dd..ff13ff25af 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -135,6 +135,9 @@ struct MigrationState /* Flag set once the migration has been asked to enter postcopy */ bool start_postcopy; + + /* Flag set once the migration thread is running (and needs joining) */ + bool migration_thread_running; }; void process_incoming_migration(QEMUFile *f); diff --git a/migration/migration.c b/migration/migration.c index afc863a84d..064986b527 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -745,7 +745,10 @@ static void migrate_fd_cleanup(void *opaque) if (s->file) { trace_migrate_fd_cleanup(); qemu_mutex_unlock_iothread(); - qemu_thread_join(&s->thread); + if (s->migration_thread_running) { + qemu_thread_join(&s->thread); + s->migration_thread_running = false; + } qemu_mutex_lock_iothread(); migrate_compress_threads_join(); @@ -1238,7 +1241,6 @@ out: return NULL; } -__attribute__ (( unused )) /* Until later in patch series */ static int open_return_path_on_source(MigrationState *ms) { @@ -1279,6 +1281,109 @@ static int await_return_path_close_on_source(MigrationState *ms) return ms->rp_state.error; } +/* + * Switch from normal iteration to postcopy + * Returns non-0 on error + */ +static int postcopy_start(MigrationState *ms, bool *old_vm_running) +{ + int ret; + const QEMUSizedBuffer *qsb; + int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); + migrate_set_state(ms, MIGRATION_STATUS_ACTIVE, + MIGRATION_STATUS_POSTCOPY_ACTIVE); + + trace_postcopy_start(); + qemu_mutex_lock_iothread(); + trace_postcopy_start_set_run(); + + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); + *old_vm_running = runstate_is_running(); + global_state_store(); + ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); + + if (ret < 0) { + goto fail; + } + + /* + * in Finish migrate and with the io-lock held everything should + * be quiet, but we've potentially still got dirty pages and we + * need to tell the destination to throw any pages it's already received + * that are dirty + */ + if (ram_postcopy_send_discard_bitmap(ms)) { + error_report("postcopy send discard bitmap failed"); + goto fail; + } + + /* + * send rest of state - note things that are doing postcopy + * will notice we're in POSTCOPY_ACTIVE and not actually + * wrap their state up here + */ + qemu_file_set_rate_limit(ms->file, INT64_MAX); + /* Ping just for debugging, helps line traces up */ + qemu_savevm_send_ping(ms->file, 2); + + /* + * While loading the device state we may trigger page transfer + * requests and the fd must be free to process those, and thus + * the destination must read the whole device state off the fd before + * it starts processing it. Unfortunately the ad-hoc migration format + * doesn't allow the destination to know the size to read without fully + * parsing it through each devices load-state code (especially the open + * coded devices that use get/put). + * So we wrap the device state up in a package with a length at the start; + * to do this we use a qemu_buf to hold the whole of the device state. + */ + QEMUFile *fb = qemu_bufopen("w", NULL); + if (!fb) { + error_report("Failed to create buffered file"); + goto fail; + } + + qemu_savevm_state_complete_precopy(fb); + qemu_savevm_send_ping(fb, 3); + + qemu_savevm_send_postcopy_run(fb); + + /* <><> end of stuff going into the package */ + qsb = qemu_buf_get(fb); + + /* Now send that blob */ + if (qemu_savevm_send_packaged(ms->file, qsb)) { + goto fail_closefb; + } + qemu_fclose(fb); + ms->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - time_at_stop; + + qemu_mutex_unlock_iothread(); + + /* + * Although this ping is just for debug, it could potentially be + * used for getting a better measurement of downtime at the source. + */ + qemu_savevm_send_ping(ms->file, 4); + + ret = qemu_file_get_error(ms->file); + if (ret) { + error_report("postcopy_start: Migration stream errored"); + migrate_set_state(ms, MIGRATION_STATUS_POSTCOPY_ACTIVE, + MIGRATION_STATUS_FAILED); + } + + return ret; + +fail_closefb: + qemu_fclose(fb); +fail: + migrate_set_state(ms, MIGRATION_STATUS_POSTCOPY_ACTIVE, + MIGRATION_STATUS_FAILED); + qemu_mutex_unlock_iothread(); + return -1; +} + /** * migration_completion: Used by migration_thread when there's not much left. * The caller 'breaks' the loop when this returns. @@ -1332,6 +1437,7 @@ fail: static void *migration_thread(void *opaque) { MigrationState *s = opaque; + /* Used by the bandwidth calcs, updated later */ int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST); int64_t initial_bytes = 0; @@ -1339,13 +1445,33 @@ static void *migration_thread(void *opaque) int64_t start_time = initial_time; int64_t end_time; bool old_vm_running = false; + bool entered_postcopy = false; + /* The active state we expect to be in; ACTIVE or POSTCOPY_ACTIVE */ + enum MigrationStatus current_active_state = MIGRATION_STATUS_ACTIVE; rcu_register_thread(); qemu_savevm_state_header(s->file); + + if (migrate_postcopy_ram()) { + /* Now tell the dest that it should open its end so it can reply */ + qemu_savevm_send_open_return_path(s->file); + + /* And do a ping that will make stuff easier to debug */ + qemu_savevm_send_ping(s->file, 1); + + /* + * Tell the destination that we *might* want to do postcopy later; + * if the other end can't do postcopy it should fail now, nice and + * early. + */ + qemu_savevm_send_postcopy_advise(s->file); + } + qemu_savevm_state_begin(s->file, &s->params); s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start; + current_active_state = MIGRATION_STATUS_ACTIVE; migrate_set_state(s, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_ACTIVE); trace_migration_thread_setup_complete(); @@ -1364,18 +1490,34 @@ static void *migration_thread(void *opaque) trace_migrate_pending(pending_size, max_size, pend_post, pend_nonpost); if (pending_size && pending_size >= max_size) { + /* Still a significant amount to transfer */ + + current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); + if (migrate_postcopy_ram() && + s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE && + pend_nonpost <= max_size && + atomic_read(&s->start_postcopy)) { + + if (!postcopy_start(s, &old_vm_running)) { + current_active_state = MIGRATION_STATUS_POSTCOPY_ACTIVE; + entered_postcopy = true; + } + + continue; + } + /* Just another iteration step */ qemu_savevm_state_iterate(s->file); } else { trace_migration_thread_low_pending(pending_size); - migration_completion(s, MIGRATION_STATUS_ACTIVE, + migration_completion(s, current_active_state, &old_vm_running, &start_time); break; } } if (qemu_file_get_error(s->file)) { - migrate_set_state(s, MIGRATION_STATUS_ACTIVE, - MIGRATION_STATUS_FAILED); + migrate_set_state(s, current_active_state, MIGRATION_STATUS_FAILED); + trace_migration_thread_file_err(); break; } current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); @@ -1406,6 +1548,7 @@ static void *migration_thread(void *opaque) } } + trace_migration_thread_after_loop(); /* If we enabled cpu throttling for auto-converge, turn it off. */ cpu_throttle_stop(); end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); @@ -1415,14 +1558,16 @@ static void *migration_thread(void *opaque) if (s->state == MIGRATION_STATUS_COMPLETED) { uint64_t transferred_bytes = qemu_ftell(s->file); s->total_time = end_time - s->total_time; - s->downtime = end_time - start_time; + if (!entered_postcopy) { + s->downtime = end_time - start_time; + } if (s->total_time) { s->mbps = (((double) transferred_bytes * 8.0) / ((double) s->total_time)) / 1000; } runstate_set(RUN_STATE_POSTMIGRATE); } else { - if (old_vm_running) { + if (old_vm_running && !entered_postcopy) { vm_start(); } } @@ -1445,9 +1590,24 @@ void migrate_fd_connect(MigrationState *s) /* Notify before starting migration thread */ notifier_list_notify(&migration_state_notifiers, s); + /* + * Open the return path; currently for postcopy but other things might + * also want it. + */ + if (migrate_postcopy_ram()) { + if (open_return_path_on_source(s)) { + error_report("Unable to open return-path for postcopy"); + migrate_set_state(s, MIGRATION_STATUS_SETUP, + MIGRATION_STATUS_FAILED); + migrate_fd_cleanup(s); + return; + } + } + migrate_compress_threads_create(); qemu_thread_create(&s->thread, "migration", migration_thread, s, QEMU_THREAD_JOINABLE); + s->migration_thread_running = true; } PostcopyState postcopy_state_get(void) diff --git a/trace-events b/trace-events index 47d3be31e1..9b7876eb8e 100644 --- a/trace-events +++ b/trace-events @@ -1453,9 +1453,13 @@ migrate_fd_error(void) "" migrate_fd_cancel(void) "" migrate_pending(uint64_t size, uint64_t max, uint64_t post, uint64_t nonpost) "pending size %" PRIu64 " max %" PRIu64 " (post=%" PRIu64 " nonpost=%" PRIu64 ")" migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d" +migration_thread_after_loop(void) "" +migration_thread_file_err(void) "" migration_thread_setup_complete(void) "" open_return_path_on_source(void) "" open_return_path_on_source_continue(void) "" +postcopy_start(void) "" +postcopy_start_set_run(void) "" source_return_path_thread_bad_end(void) "" source_return_path_thread_end(void) "" source_return_path_thread_entry(void) "" |