Fabiano Rosas <faro...@suse.de> writes:
> While we cannot yet disentangle the multifd packet from page data, we
> can make the code a bit cleaner by setting the page-related fields in
> a separate function.
>
> Signed-off-by: Fabiano Rosas <faro...@suse.de>
> ---
> migration/multifd.c | 104 +++++++++++++++++++++++++++++---------------
> 1 file changed, 68 insertions(+), 36 deletions(-)
>
> diff --git a/migration/multifd.c b/migration/multifd.c
> index c4a952576d..6fe339b378 100644
> --- a/migration/multifd.c
> +++ b/migration/multifd.c
> @@ -407,65 +407,64 @@ static void multifd_pages_clear(MultiFDPages_t *pages)
> g_free(pages);
> }
>
> -void multifd_send_fill_packet(MultiFDSendParams *p)
> +static void multifd_ram_fill_packet(MultiFDSendParams *p)
> {
> MultiFDPacket_t *packet = p->packet;
> MultiFDPages_t *pages = p->data->opaque;
> - uint64_t packet_num;
> uint32_t zero_num = pages->num - pages->normal_num;
> - int i;
>
> - packet->flags = cpu_to_be32(p->flags);
> packet->pages_alloc = cpu_to_be32(pages->allocated);
> packet->normal_pages = cpu_to_be32(pages->normal_num);
> packet->zero_pages = cpu_to_be32(zero_num);
> - packet->next_packet_size = cpu_to_be32(p->next_packet_size);
> -
> - packet_num = qatomic_fetch_inc(&multifd_send_state->packet_num);
> - packet->packet_num = cpu_to_be64(packet_num);
>
> if (pages->block) {
> strncpy(packet->ramblock, pages->block->idstr, 256);
> }
>
> - for (i = 0; i < pages->num; i++) {
> + for (int i = 0; i < pages->num; i++) {
> /* there are architectures where ram_addr_t is 32 bit */
> uint64_t temp = pages->offset[i];
>
> packet->offset[i] = cpu_to_be64(temp);
> }
>
> - p->packets_sent++;
> p->total_normal_pages += pages->normal_num;
> p->total_zero_pages += zero_num;
> +}
>
> - trace_multifd_send(p->id, packet_num, pages->normal_num, zero_num,
> +void multifd_send_fill_packet(MultiFDSendParams *p)
> +{
> + MultiFDPacket_t *packet = p->packet;
> + uint64_t packet_num;
> +
> + memset(packet, 0, p->packet_len);
> +
> + packet->magic = cpu_to_be32(MULTIFD_MAGIC);
> + packet->version = cpu_to_be32(MULTIFD_VERSION);
> +
> + packet->flags = cpu_to_be32(p->flags);
> + packet->next_packet_size = cpu_to_be32(p->next_packet_size);
> +
> + packet_num = qatomic_fetch_inc(&multifd_send_state->packet_num);
> + packet->packet_num = cpu_to_be64(packet_num);
> +
> + p->packets_sent++;
> +
> + if (p->data) {
This needs to be !(p->flags & MULTIFD_SYNC). In v2 I'll add it in a
separate patch to make it clear:
-->8--
>From e0dd1e0f10b6adb5d419ff68c1ef3b76d2fcf1d4 Mon Sep 17 00:00:00 2001
From: Fabiano Rosas <faro...@suse.de>
Date: Fri, 19 Jul 2024 11:28:33 -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.
Signed-off-by: Fabiano Rosas <faro...@suse.de>
---
migration/multifd.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/migration/multifd.c b/migration/multifd.c
index 3809890082..6e6e62d352 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -431,6 +431,7 @@ 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);
@@ -445,7 +446,9 @@ 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(p->id, packet_num,
be32_to_cpu(packet->normal_pages),
@@ -556,7 +559,12 @@ 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) {
+ p->normal_num = 0;
+ p->zero_num = 0;
+ } else {
+ ret = multifd_ram_unfill_packet(p, errp);
+ }
trace_multifd_recv(p->id, p->packet_num, p->normal_num, p->zero_num,
p->flags, p->next_packet_size);
--
2.35.3
