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Re: [PATCH v7 03/12] vhost: Delete useless read memory barrier
From: |
Jason Wang |
Subject: |
Re: [PATCH v7 03/12] vhost: Delete useless read memory barrier |
Date: |
Fri, 5 Aug 2022 11:48:55 +0800 |
On Fri, Aug 5, 2022 at 2:29 AM Eugenio Pérez <eperezma@redhat.com> wrote:
>
> As discussed in previous series [1], this memory barrier is useless with
> the atomic read of used idx at vhost_svq_more_used. Deleting it.
>
> [1] https://lists.nongnu.org/archive/html/qemu-devel/2022-07/msg02616.html
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
> ---
> hw/virtio/vhost-shadow-virtqueue.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/hw/virtio/vhost-shadow-virtqueue.c
> b/hw/virtio/vhost-shadow-virtqueue.c
> index e6eebd0e8d..1b49bf54f2 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.c
> +++ b/hw/virtio/vhost-shadow-virtqueue.c
> @@ -509,9 +509,6 @@ size_t vhost_svq_poll(VhostShadowVirtqueue *svq)
> if (unlikely(g_get_monotonic_time() - start_us > 10e6)) {
> return 0;
> }
> -
> - /* Make sure we read new used_idx */
> - smp_rmb();
> } while (true);
> }
>
> --
> 2.31.1
>
- [PATCH v7 00/12] NIC vhost-vdpa state restore via Shadow CVQ, Eugenio Pérez, 2022/08/04
- [PATCH v7 02/12] vhost: use SVQ element ndescs instead of opaque data for desc validation, Eugenio Pérez, 2022/08/04
- [PATCH v7 03/12] vhost: Delete useless read memory barrier, Eugenio Pérez, 2022/08/04
- Re: [PATCH v7 03/12] vhost: Delete useless read memory barrier,
Jason Wang <=
- [PATCH v7 04/12] vhost: Do not depend on !NULL VirtQueueElement on vhost_svq_flush, Eugenio Pérez, 2022/08/04
- [PATCH v7 05/12] vhost_net: Add NetClientInfo prepare callback, Eugenio Pérez, 2022/08/04
- [PATCH v7 07/12] vdpa: add net_vhost_vdpa_cvq_info NetClientInfo, Eugenio Pérez, 2022/08/04
- [PATCH v7 06/12] vhost_net: Add NetClientInfo stop callback, Eugenio Pérez, 2022/08/04
- [PATCH v7 01/12] vhost: stop transfer elem ownership in vhost_handle_guest_kick, Eugenio Pérez, 2022/08/04
- [PATCH v7 08/12] vdpa: Move command buffers map to start of net device, Eugenio Pérez, 2022/08/04