diff options
| -rw-r--r-- | migration/migration.c | 11 | ||||
| -rw-r--r-- | migration/multifd.c | 37 | ||||
| -rw-r--r-- | migration/multifd.h | 2 | ||||
| -rw-r--r-- | migration/socket.c | 5 |
4 files changed, 50 insertions, 5 deletions
diff --git a/migration/migration.c b/migration/migration.c index 4b6df2e..31739b2 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1497,7 +1497,16 @@ static bool migrate_params_check(MigrationParameters *params, Error **errp) error_prepend(errp, "Invalid mapping given for block-bitmap-mapping: "); return false; } - +#ifdef CONFIG_LINUX + if (params->zero_copy_send && + (!migrate_use_multifd() || + params->multifd_compression != MULTIFD_COMPRESSION_NONE || + (params->tls_creds && *params->tls_creds))) { + error_setg(errp, + "Zero copy only available for non-compressed non-TLS multifd migration"); + return false; + } +#endif return true; } diff --git a/migration/multifd.c b/migration/multifd.c index 2541cd2..9282ab6 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -569,6 +569,7 @@ void multifd_save_cleanup(void) int multifd_send_sync_main(QEMUFile *f) { int i; + bool flush_zero_copy; if (!migrate_use_multifd()) { return 0; @@ -579,6 +580,20 @@ int multifd_send_sync_main(QEMUFile *f) return -1; } } + + /* + * When using zero-copy, it's necessary to flush the pages before any of + * the pages can be sent again, so we'll make sure the new version of the + * pages will always arrive _later_ than the old pages. + * + * Currently we achieve this by flushing the zero-page requested writes + * per ram iteration, but in the future we could potentially optimize it + * to be less frequent, e.g. only after we finished one whole scanning of + * all the dirty bitmaps. + */ + + flush_zero_copy = migrate_use_zero_copy_send(); + for (i = 0; i < migrate_multifd_channels(); i++) { MultiFDSendParams *p = &multifd_send_state->params[i]; @@ -600,6 +615,17 @@ int multifd_send_sync_main(QEMUFile *f) ram_counters.transferred += p->packet_len; qemu_mutex_unlock(&p->mutex); qemu_sem_post(&p->sem); + + if (flush_zero_copy && p->c) { + int ret; + Error *err = NULL; + + ret = qio_channel_flush(p->c, &err); + if (ret < 0) { + error_report_err(err); + return -1; + } + } } for (i = 0; i < migrate_multifd_channels(); i++) { MultiFDSendParams *p = &multifd_send_state->params[i]; @@ -684,8 +710,8 @@ static void *multifd_send_thread(void *opaque) p->iov[0].iov_base = p->packet; } - ret = qio_channel_writev_all(p->c, p->iov, p->iovs_num, - &local_err); + ret = qio_channel_writev_full_all(p->c, p->iov, p->iovs_num, NULL, + 0, p->write_flags, &local_err); if (ret != 0) { break; } @@ -913,6 +939,13 @@ int multifd_save_setup(Error **errp) /* We need one extra place for the packet header */ p->iov = g_new0(struct iovec, page_count + 1); p->normal = g_new0(ram_addr_t, page_count); + + if (migrate_use_zero_copy_send()) { + p->write_flags = QIO_CHANNEL_WRITE_FLAG_ZERO_COPY; + } else { + p->write_flags = 0; + } + socket_send_channel_create(multifd_new_send_channel_async, p); } diff --git a/migration/multifd.h b/migration/multifd.h index bcf5992..4d8d89e 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -92,6 +92,8 @@ typedef struct { uint32_t packet_len; /* pointer to the packet */ MultiFDPacket_t *packet; + /* multifd flags for sending ram */ + int write_flags; /* multifd flags for each packet */ uint32_t flags; /* size of the next packet that contains pages */ diff --git a/migration/socket.c b/migration/socket.c index 3754d8f..4fd5e85 100644 --- a/migration/socket.c +++ b/migration/socket.c @@ -79,8 +79,9 @@ static void socket_outgoing_migration(QIOTask *task, trace_migration_socket_outgoing_connected(data->hostname); - if (migrate_use_zero_copy_send()) { - error_setg(&err, "Zero copy send not available in migration"); + if (migrate_use_zero_copy_send() && + !qio_channel_has_feature(sioc, QIO_CHANNEL_FEATURE_WRITE_ZERO_COPY)) { + error_setg(&err, "Zero copy send feature not detected in host kernel"); } out: |