* Juan Quintela (quint...@redhat.com) wrote:
> We do the send_prepare() and the fill of the head packet without the
> mutex held. It will help a lot for compression and later in the
> series for zero pages.
>
> Notice that we can use p->pages without holding p->mutex because
> p->pending_job == 1.
>
> Signed-off-by: Juan Quintela <quint...@redhat.com>
> ---
> migration/multifd.h | 2 ++
> migration/multifd.c | 11 ++++++-----
> 2 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/migration/multifd.h b/migration/multifd.h
> index af8ce8921d..d48597a1ea 100644
> --- a/migration/multifd.h
> +++ b/migration/multifd.h
> @@ -109,7 +109,9 @@ typedef struct {
> /* array of pages to sent.
> * The owner of 'pages' depends of 'pending_job' value:
> * pending_job == 0 -> migration_thread can use it.
> + * No need for mutex lock.
> * pending_job != 0 -> multifd_channel can use it.
> + * No need for mutex lock.
> */
> MultiFDPages_t *pages;
>
> diff --git a/migration/multifd.c b/migration/multifd.c
> index 69b9d7cf98..056599cbaf 100644
> --- a/migration/multifd.c
> +++ b/migration/multifd.c
> @@ -661,6 +661,8 @@ static void *multifd_send_thread(void *opaque)
> p->flags |= MULTIFD_FLAG_SYNC;
> p->sync_needed = false;
> }
> + qemu_mutex_unlock(&p->mutex);
> +
> p->normal_num = 0;
>
> if (use_zero_copy_send) {
> @@ -682,11 +684,6 @@ static void *multifd_send_thread(void *opaque)
Looking at my source tree, without the rest of your series, I see an
unlock just before this pair of }'s; doesn't that need to go?
Dave
> }
> }
> multifd_send_fill_packet(p);
> - p->num_packets++;
> - p->total_normal_pages += p->normal_num;
> - p->pages->num = 0;
> - p->pages->block = NULL;
> - qemu_mutex_unlock(&p->mutex);
>
> trace_multifd_send(p->id, packet_num, p->normal_num, p->flags,
> p->next_packet_size);
> @@ -711,6 +708,10 @@ static void *multifd_send_thread(void *opaque)
> }
>
> qemu_mutex_lock(&p->mutex);
> + p->num_packets++;
> + p->total_normal_pages += p->normal_num;
> + p->pages->num = 0;
> + p->pages->block = NULL;
> p->sent_bytes += p->packet_len;;
> p->sent_bytes += p->next_packet_size;
> p->pending_job--;
> --
> 2.35.3
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
