diff options
| -rw-r--r-- | include/migration/register.h | 2 | ||||
| -rw-r--r-- | migration/migration.c | 32 | ||||
| -rw-r--r-- | migration/migration.h | 14 | ||||
| -rw-r--r-- | migration/savevm.c | 54 | ||||
| -rw-r--r-- | migration/savevm.h | 1 | ||||
| -rw-r--r-- | migration/trace-events | 3 |
6 files changed, 104 insertions, 2 deletions
diff --git a/include/migration/register.h b/include/migration/register.h index a8dfd8fefd..90914f32f5 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -71,6 +71,8 @@ typedef struct SaveVMHandlers { int (*load_cleanup)(void *opaque); /* Called when postcopy migration wants to resume from failure */ int (*resume_prepare)(MigrationState *s, void *opaque); + /* Checks if switchover ack should be used. Called only in dest */ + bool (*switchover_ack_needed)(void *opaque); } SaveVMHandlers; int register_savevm_live(const char *idstr, diff --git a/migration/migration.c b/migration/migration.c index dc05c6f6ea..7653787f74 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -78,6 +78,7 @@ enum mig_rp_message_type { MIG_RP_MSG_REQ_PAGES, /* data (start: be64, len: be32) */ MIG_RP_MSG_RECV_BITMAP, /* send recved_bitmap back to source */ MIG_RP_MSG_RESUME_ACK, /* tell source that we are ready to resume */ + MIG_RP_MSG_SWITCHOVER_ACK, /* Tell source it's OK to do switchover */ MIG_RP_MSG_MAX }; @@ -760,6 +761,11 @@ bool migration_has_all_channels(void) return true; } +int migrate_send_rp_switchover_ack(MigrationIncomingState *mis) +{ + return migrate_send_rp_message(mis, MIG_RP_MSG_SWITCHOVER_ACK, 0, NULL); +} + /* * Send a 'SHUT' message on the return channel with the given value * to indicate that we've finished with the RP. Non-0 value indicates @@ -1405,6 +1411,7 @@ void migrate_init(MigrationState *s) s->vm_old_state = -1; s->iteration_initial_bytes = 0; s->threshold_size = 0; + s->switchover_acked = false; } int migrate_add_blocker_internal(Error *reason, Error **errp) @@ -1721,6 +1728,7 @@ static struct rp_cmd_args { [MIG_RP_MSG_REQ_PAGES_ID] = { .len = -1, .name = "REQ_PAGES_ID" }, [MIG_RP_MSG_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" }, [MIG_RP_MSG_RESUME_ACK] = { .len = 4, .name = "RESUME_ACK" }, + [MIG_RP_MSG_SWITCHOVER_ACK] = { .len = 0, .name = "SWITCHOVER_ACK" }, [MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" }, }; @@ -1959,6 +1967,11 @@ retry: } break; + case MIG_RP_MSG_SWITCHOVER_ACK: + ms->switchover_acked = true; + trace_source_return_path_thread_switchover_acked(); + break; + default: break; } @@ -2693,6 +2706,20 @@ static void migration_update_counters(MigrationState *s, bandwidth, s->threshold_size); } +static bool migration_can_switchover(MigrationState *s) +{ + if (!migrate_switchover_ack()) { + return true; + } + + /* No reason to wait for switchover ACK if VM is stopped */ + if (!runstate_is_running()) { + return true; + } + + return s->switchover_acked; +} + /* Migration thread iteration status */ typedef enum { MIG_ITERATE_RESUME, /* Resume current iteration */ @@ -2708,6 +2735,7 @@ static MigIterateState migration_iteration_run(MigrationState *s) { uint64_t must_precopy, can_postcopy; bool in_postcopy = s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE; + bool can_switchover = migration_can_switchover(s); qemu_savevm_state_pending_estimate(&must_precopy, &can_postcopy); uint64_t pending_size = must_precopy + can_postcopy; @@ -2720,14 +2748,14 @@ static MigIterateState migration_iteration_run(MigrationState *s) trace_migrate_pending_exact(pending_size, must_precopy, can_postcopy); } - if (!pending_size || pending_size < s->threshold_size) { + if ((!pending_size || pending_size < s->threshold_size) && can_switchover) { trace_migration_thread_low_pending(pending_size); migration_completion(s); return MIG_ITERATE_BREAK; } /* Still a significant amount to transfer */ - if (!in_postcopy && must_precopy <= s->threshold_size && + if (!in_postcopy && must_precopy <= s->threshold_size && can_switchover && qatomic_read(&s->start_postcopy)) { if (postcopy_start(s)) { error_report("%s: postcopy failed to start", __func__); diff --git a/migration/migration.h b/migration/migration.h index 30c3e97635..c859a0d35e 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -210,6 +210,13 @@ struct MigrationIncomingState { * contains valid information. */ QemuMutex page_request_mutex; + + /* + * Number of devices that have yet to approve switchover. When this reaches + * zero an ACK that it's OK to do switchover is sent to the source. No lock + * is needed as this field is updated serially. + */ + unsigned int switchover_ack_pending_num; }; MigrationIncomingState *migration_incoming_get_current(void); @@ -440,6 +447,12 @@ struct MigrationState { /* QEMU_VM_VMDESCRIPTION content filled for all non-iterable devices. */ JSONWriter *vmdesc; + + /* + * Indicates whether an ACK from the destination that it's OK to do + * switchover has been received. + */ + bool switchover_acked; }; void migrate_set_state(int *state, int old_state, int new_state); @@ -480,6 +493,7 @@ int migrate_send_rp_message_req_pages(MigrationIncomingState *mis, void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis, char *block_name); void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value); +int migrate_send_rp_switchover_ack(MigrationIncomingState *mis); void dirty_bitmap_mig_before_vm_start(void); void dirty_bitmap_mig_cancel_outgoing(void); diff --git a/migration/savevm.c b/migration/savevm.c index bc284087f9..cdf4793924 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2360,6 +2360,21 @@ static int loadvm_process_command(QEMUFile *f) error_report("CMD_OPEN_RETURN_PATH failed"); return -1; } + + /* + * Switchover ack is enabled but no device uses it, so send an ACK to + * source that it's OK to switchover. Do it here, after return path has + * been created. + */ + if (migrate_switchover_ack() && !mis->switchover_ack_pending_num) { + int ret = migrate_send_rp_switchover_ack(mis); + if (ret) { + error_report( + "Could not send switchover ack RP MSG, err %d (%s)", ret, + strerror(-ret)); + return ret; + } + } break; case MIG_CMD_PING: @@ -2586,6 +2601,23 @@ static int qemu_loadvm_state_header(QEMUFile *f) return 0; } +static void qemu_loadvm_state_switchover_ack_needed(MigrationIncomingState *mis) +{ + SaveStateEntry *se; + + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { + if (!se->ops || !se->ops->switchover_ack_needed) { + continue; + } + + if (se->ops->switchover_ack_needed(se->opaque)) { + mis->switchover_ack_pending_num++; + } + } + + trace_loadvm_state_switchover_ack_needed(mis->switchover_ack_pending_num); +} + static int qemu_loadvm_state_setup(QEMUFile *f) { SaveStateEntry *se; @@ -2789,6 +2821,10 @@ int qemu_loadvm_state(QEMUFile *f) return -EINVAL; } + if (migrate_switchover_ack()) { + qemu_loadvm_state_switchover_ack_needed(mis); + } + cpu_synchronize_all_pre_loadvm(); ret = qemu_loadvm_state_main(f, mis); @@ -2862,6 +2898,24 @@ int qemu_load_device_state(QEMUFile *f) return 0; } +int qemu_loadvm_approve_switchover(void) +{ + MigrationIncomingState *mis = migration_incoming_get_current(); + + if (!mis->switchover_ack_pending_num) { + return -EINVAL; + } + + mis->switchover_ack_pending_num--; + trace_loadvm_approve_switchover(mis->switchover_ack_pending_num); + + if (mis->switchover_ack_pending_num) { + return 0; + } + + return migrate_send_rp_switchover_ack(mis); +} + bool save_snapshot(const char *name, bool overwrite, const char *vmstate, bool has_devices, strList *devices, Error **errp) { diff --git a/migration/savevm.h b/migration/savevm.h index fb636735f0..e894bbc143 100644 --- a/migration/savevm.h +++ b/migration/savevm.h @@ -65,6 +65,7 @@ int qemu_loadvm_state(QEMUFile *f); void qemu_loadvm_state_cleanup(void); int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis); int qemu_load_device_state(QEMUFile *f); +int qemu_loadvm_approve_switchover(void); int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, bool in_postcopy, bool inactivate_disks); diff --git a/migration/trace-events b/migration/trace-events index cdaef7a1ea..5259c1044b 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -7,6 +7,7 @@ qemu_loadvm_state_section_partend(uint32_t section_id) "%u" qemu_loadvm_state_post_main(int ret) "%d" qemu_loadvm_state_section_startfull(uint32_t section_id, const char *idstr, uint32_t instance_id, uint32_t version_id) "%u(%s) %u %u" qemu_savevm_send_packaged(void) "" +loadvm_state_switchover_ack_needed(unsigned int switchover_ack_pending_num) "Switchover ack pending num=%u" loadvm_state_setup(void) "" loadvm_state_cleanup(void) "" loadvm_handle_cmd_packaged(unsigned int length) "%u" @@ -23,6 +24,7 @@ loadvm_postcopy_ram_handle_discard_end(void) "" loadvm_postcopy_ram_handle_discard_header(const char *ramid, uint16_t len) "%s: %ud" loadvm_process_command(const char *s, uint16_t len) "com=%s len=%d" loadvm_process_command_ping(uint32_t val) "0x%x" +loadvm_approve_switchover(unsigned int switchover_ack_pending_num) "Switchover ack pending num=%u" postcopy_ram_listen_thread_exit(void) "" postcopy_ram_listen_thread_start(void) "" qemu_savevm_send_postcopy_advise(void) "" @@ -180,6 +182,7 @@ source_return_path_thread_loop_top(void) "" source_return_path_thread_pong(uint32_t val) "0x%x" source_return_path_thread_shut(uint32_t val) "0x%x" source_return_path_thread_resume_ack(uint32_t v) "%"PRIu32 +source_return_path_thread_switchover_acked(void) "" migration_thread_low_pending(uint64_t pending) "%" PRIu64 migrate_transferred(uint64_t tranferred, uint64_t time_spent, uint64_t bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 " bandwidth %" PRIu64 " max_size %" PRId64 process_incoming_migration_co_end(int ret, int ps) "ret=%d postcopy-state=%d" |