From d48c3a044537689866fe44e65d24c7d39a68868a Mon Sep 17 00:00:00 2001 From: Juan Quintela Date: Fri, 19 Nov 2021 15:35:58 +0100 Subject: [PATCH] multifd: Use a single writev on the send side Until now, we wrote the packet header with write(), and the rest of the pages with writev(). Just increase the size of the iovec and do a single writev(). Signed-off-by: Juan Quintela Reviewed-by: Dr. David Alan Gilbert --- migration/multifd.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index 96b9cc0d8b..1d4885e1a0 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -646,7 +646,7 @@ static void *multifd_send_thread(void *opaque) uint32_t used = p->pages->num; uint64_t packet_num = p->packet_num; uint32_t flags = p->flags; - p->iovs_num = 0; + p->iovs_num = 1; if (used) { ret = multifd_send_state->ops->send_prepare(p, &local_err); @@ -666,20 +666,15 @@ static void *multifd_send_thread(void *opaque) trace_multifd_send(p->id, packet_num, used, flags, p->next_packet_size); - ret = qio_channel_write_all(p->c, (void *)p->packet, - p->packet_len, &local_err); + p->iov[0].iov_len = p->packet_len; + p->iov[0].iov_base = p->packet; + + ret = qio_channel_writev_all(p->c, p->iov, p->iovs_num, + &local_err); if (ret != 0) { break; } - if (used) { - ret = qio_channel_writev_all(p->c, p->iov, p->iovs_num, - &local_err); - if (ret != 0) { - break; - } - } - qemu_mutex_lock(&p->mutex); p->pending_job--; qemu_mutex_unlock(&p->mutex); @@ -916,7 +911,8 @@ int multifd_save_setup(Error **errp) p->packet->version = cpu_to_be32(MULTIFD_VERSION); p->name = g_strdup_printf("multifdsend_%d", i); p->tls_hostname = g_strdup(s->hostname); - p->iov = g_new0(struct iovec, page_count); + /* We need one extra place for the packet header */ + p->iov = g_new0(struct iovec, page_count + 1); socket_send_channel_create(multifd_new_send_channel_async, p); }