diff options
| -rw-r--r-- | migration/migration.c | 72 | ||||
| -rw-r--r-- | migration/migration.h | 6 | ||||
| -rw-r--r-- | migration/postcopy-ram.c | 17 | ||||
| -rw-r--r-- | migration/postcopy-ram.h | 2 | ||||
| -rw-r--r-- | migration/savevm.c | 6 |
5 files changed, 82 insertions, 21 deletions
diff --git a/migration/migration.c b/migration/migration.c index a2e362541d..a5c22e327d 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -235,6 +235,8 @@ void migration_object_init(void) qemu_sem_init(¤t_incoming->postcopy_pause_sem_dst, 0); qemu_sem_init(¤t_incoming->postcopy_pause_sem_fault, 0); qemu_sem_init(¤t_incoming->postcopy_pause_sem_fast_load, 0); + qemu_sem_init(¤t_incoming->postcopy_qemufile_dst_done, 0); + qemu_mutex_init(¤t_incoming->page_request_mutex); current_incoming->page_requested = g_tree_new(page_request_addr_cmp); @@ -737,6 +739,31 @@ void migration_fd_process_incoming(QEMUFile *f, Error **errp) migration_incoming_process(); } +/* + * Returns true when we want to start a new incoming migration process, + * false otherwise. + */ +static bool migration_should_start_incoming(bool main_channel) +{ + /* Multifd doesn't start unless all channels are established */ + if (migrate_use_multifd()) { + return migration_has_all_channels(); + } + + /* Preempt channel only starts when the main channel is created */ + if (migrate_postcopy_preempt()) { + return main_channel; + } + + /* + * For all the rest types of migration, we should only reach here when + * it's the main channel that's being created, and we should always + * proceed with this channel. + */ + assert(main_channel); + return true; +} + void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp) { MigrationIncomingState *mis = migration_incoming_get_current(); @@ -798,7 +825,7 @@ void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp) } } - if (migration_has_all_channels()) { + if (migration_should_start_incoming(default_channel)) { /* If it's a recovery, we're done */ if (postcopy_try_recover()) { return; @@ -3159,6 +3186,13 @@ static int await_return_path_close_on_source(MigrationState *ms) return ms->rp_state.error; } +static inline void +migration_wait_main_channel(MigrationState *ms) +{ + /* Wait until one PONG message received */ + qemu_sem_wait(&ms->rp_state.rp_pong_acks); +} + /* * Switch from normal iteration to postcopy * Returns non-0 on error @@ -3173,9 +3207,12 @@ static int postcopy_start(MigrationState *ms) bool restart_block = false; int cur_state = MIGRATION_STATUS_ACTIVE; - if (postcopy_preempt_wait_channel(ms)) { - migrate_set_state(&ms->state, ms->state, MIGRATION_STATUS_FAILED); - return -1; + if (migrate_postcopy_preempt()) { + migration_wait_main_channel(ms); + if (postcopy_preempt_establish_channel(ms)) { + migrate_set_state(&ms->state, ms->state, MIGRATION_STATUS_FAILED); + return -1; + } } if (!migrate_pause_before_switchover()) { @@ -3587,6 +3624,20 @@ static int postcopy_do_resume(MigrationState *s) } /* + * If preempt is enabled, re-establish the preempt channel. Note that + * we do it after resume prepare to make sure the main channel will be + * created before the preempt channel. E.g. with weak network, the + * dest QEMU may get messed up with the preempt and main channels on + * the order of connection setup. This guarantees the correct order. + */ + ret = postcopy_preempt_establish_channel(s); + if (ret) { + error_report("%s: postcopy_preempt_establish_channel(): %d", + __func__, ret); + return ret; + } + + /* * Last handshake with destination on the resume (destination will * switch to postcopy-active afterwards) */ @@ -3647,14 +3698,6 @@ static MigThrError postcopy_pause(MigrationState *s) if (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER) { /* Woken up by a recover procedure. Give it a shot */ - if (postcopy_preempt_wait_channel(s)) { - /* - * Preempt enabled, and new channel create failed; loop - * back to wait for another recovery. - */ - continue; - } - /* * Firstly, let's wake up the return path now, with a new * return path channel. @@ -4347,11 +4390,6 @@ void migrate_fd_connect(MigrationState *s, Error *error_in) } } - /* This needs to be done before resuming a postcopy */ - if (migrate_postcopy_preempt()) { - postcopy_preempt_setup(s); - } - if (resume) { /* Wakeup the main migration thread to do the recovery */ migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_PAUSED, diff --git a/migration/migration.h b/migration/migration.h index 4cb1cb6fa8..2da2f8a164 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -116,6 +116,12 @@ struct MigrationIncomingState { unsigned int postcopy_channels; /* QEMUFile for postcopy only; it'll be handled by a separate thread */ QEMUFile *postcopy_qemufile_dst; + /* + * When postcopy_qemufile_dst is properly setup, this sem is posted. + * One can wait on this semaphore to wait until the preempt channel is + * properly setup. + */ + QemuSemaphore postcopy_qemufile_dst_done; /* Postcopy priority thread is used to receive postcopy requested pages */ QemuThread postcopy_prio_thread; bool postcopy_prio_thread_created; diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index de6d4a3fd4..f54f44d899 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -1198,6 +1198,11 @@ int postcopy_ram_incoming_setup(MigrationIncomingState *mis) if (migrate_postcopy_preempt()) { /* + * The preempt channel is established in asynchronous way. Wait + * for its completion. + */ + qemu_sem_wait(&mis->postcopy_qemufile_dst_done); + /* * This thread needs to be created after the temp pages because * it'll fetch RAM_CHANNEL_POSTCOPY PostcopyTmpPage immediately. */ @@ -1544,6 +1549,7 @@ void postcopy_preempt_new_channel(MigrationIncomingState *mis, QEMUFile *file) */ qemu_file_set_blocking(file, true); mis->postcopy_qemufile_dst = file; + qemu_sem_post(&mis->postcopy_qemufile_dst_done); trace_postcopy_preempt_new_channel(); } @@ -1612,14 +1618,21 @@ out: postcopy_preempt_send_channel_done(s, ioc, local_err); } -/* Returns 0 if channel established, -1 for error. */ -int postcopy_preempt_wait_channel(MigrationState *s) +/* + * This function will kick off an async task to establish the preempt + * channel, and wait until the connection setup completed. Returns 0 if + * channel established, -1 for error. + */ +int postcopy_preempt_establish_channel(MigrationState *s) { /* If preempt not enabled, no need to wait */ if (!migrate_postcopy_preempt()) { return 0; } + /* Kick off async task to establish preempt channel */ + postcopy_preempt_setup(s); + /* * We need the postcopy preempt channel to be established before * starting doing anything. diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h index d5604cbcf1..b4867a32d5 100644 --- a/migration/postcopy-ram.h +++ b/migration/postcopy-ram.h @@ -192,6 +192,6 @@ enum PostcopyChannels { void postcopy_preempt_new_channel(MigrationIncomingState *mis, QEMUFile *file); void postcopy_preempt_setup(MigrationState *s); -int postcopy_preempt_wait_channel(MigrationState *s); +int postcopy_preempt_establish_channel(MigrationState *s); #endif diff --git a/migration/savevm.c b/migration/savevm.c index ce181e21e1..b5e6962bb6 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2200,7 +2200,11 @@ static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis) qemu_sem_post(&mis->postcopy_pause_sem_fault); if (migrate_postcopy_preempt()) { - /* The channel should already be setup again; make sure of it */ + /* + * The preempt channel will be created in async manner, now let's + * wait for it and make sure it's created. + */ + qemu_sem_wait(&mis->postcopy_qemufile_dst_done); assert(mis->postcopy_qemufile_dst); /* Kick the fast ram load thread too */ qemu_sem_post(&mis->postcopy_pause_sem_fast_load); |