From d7e58f412cf6c5426efda60558f0ccfbf709f646 Mon Sep 17 00:00:00 2001 From: Fabiano Rosas Date: Tue, 27 Aug 2024 14:45:58 -0300 Subject: [PATCH] migration/multifd: Don't send ram data during SYNC Skip saving and loading any ram data in the packet in the case of a SYNC. This fixes a shortcoming of the current code which requires a reset of the MultiFDPages_t fields right after the previous pending_job finishes, otherwise the very next job might be a SYNC and multifd_send_fill_packet() will put the stale values in the packet. By not calling multifd_ram_fill_packet(), we can stop resetting MultiFDPages_t in the multifd core and leave that to the client code. Actually moving the reset function is not yet done because pages->num==0 is used by the client code to determine whether the MultiFDPages_t needs to be flushed. The subsequent patches will replace that with a generic flag that is not dependent on MultiFDPages_t. Reviewed-by: Peter Xu Signed-off-by: Fabiano Rosas --- migration/multifd.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index d64fcdf4ac..3a164c124d 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -452,6 +452,7 @@ void multifd_send_fill_packet(MultiFDSendParams *p) { MultiFDPacket_t *packet = p->packet; uint64_t packet_num; + bool sync_packet = p->flags & MULTIFD_FLAG_SYNC; memset(packet, 0, p->packet_len); @@ -466,7 +467,9 @@ void multifd_send_fill_packet(MultiFDSendParams *p) p->packets_sent++; - multifd_ram_fill_packet(p); + if (!sync_packet) { + multifd_ram_fill_packet(p); + } trace_multifd_send_fill(p->id, packet_num, p->flags, p->next_packet_size); @@ -574,7 +577,9 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) p->packet_num = be64_to_cpu(packet->packet_num); p->packets_recved++; - ret = multifd_ram_unfill_packet(p, errp); + if (!(p->flags & MULTIFD_FLAG_SYNC)) { + ret = multifd_ram_unfill_packet(p, errp); + } trace_multifd_recv_unfill(p->id, p->packet_num, p->flags, p->next_packet_size); @@ -1536,7 +1541,9 @@ static void *multifd_recv_thread(void *opaque) flags = p->flags; /* recv methods don't know how to handle the SYNC flag */ p->flags &= ~MULTIFD_FLAG_SYNC; - has_data = p->normal_num || p->zero_num; + if (!(flags & MULTIFD_FLAG_SYNC)) { + has_data = p->normal_num || p->zero_num; + } qemu_mutex_unlock(&p->mutex); } else { /*