Linux Virtualization - Aug 2023 - [PATCH vhost v13 05/12] virtio_ring: introduce virtqueue_dma_dev()

On Tue, Aug 15, 2023 at 2:32?PM Xuan Zhuo <xuanzhuo at linux.alibaba.com>
wrote:
>
>
> Hi, Jason
>
> Could you skip this patch?
I'm fine with either merging or dropping this.
>
> Let we review other patches firstly?
I will be on vacation soon, and won't have time to do this until next week.

But I spot two possible "issues":

1) the DMA metadata were stored in the headroom of the page, this
breaks frags coalescing, we need to benchmark it's impact
2) pre mapped DMA addresses were not reused in the case of XDP_TX/XDP_REDIRECT

I see Michael has merge this series so I'm fine to let it go first.

Thanks
>
> Thanks.
>

On Tue, 15 Aug 2023 15:50:23 +0800, Jason Wang <jasowang at redhat.com>
wrote:
> On Tue, Aug 15, 2023 at 2:32?PM Xuan Zhuo <xuanzhuo at
linux.alibaba.com> wrote:
> >
> >
> > Hi, Jason
> >
> > Could you skip this patch?
>
> I'm fine with either merging or dropping this.
>
> >
> > Let we review other patches firstly?
>
> I will be on vacation soon, and won't have time to do this until next
week.
Have a happly vacation.
>
> But I spot two possible "issues":
>
> 1) the DMA metadata were stored in the headroom of the page, this
> breaks frags coalescing, we need to benchmark it's impact
Not every page, just the first page of the COMP pages.

So I think there is no impact.

> 2) pre mapped DMA addresses were not reused in the case of
XDP_TX/XDP_REDIRECT
Because that the tx is not the premapped mode.

Thanks.
>
> I see Michael has merge this series so I'm fine to let it go first.
>
> Thanks
>
> >
> > Thanks.
> >
>

On Tue, Aug 15, 2023 at 03:50:23PM +0800, Jason Wang
wrote:
> On Tue, Aug 15, 2023 at 2:32?PM Xuan Zhuo <xuanzhuo at
linux.alibaba.com> wrote:
> >
> >
> > Hi, Jason
> >
> > Could you skip this patch?
> 
> I'm fine with either merging or dropping this.
> 
> >
> > Let we review other patches firstly?
> 
> I will be on vacation soon, and won't have time to do this until next
week.
> 
> But I spot two possible "issues":
> 
> 1) the DMA metadata were stored in the headroom of the page, this
> breaks frags coalescing, we need to benchmark it's impact
> 2) pre mapped DMA addresses were not reused in the case of
XDP_TX/XDP_REDIRECT
> 
> I see Michael has merge this series so I'm fine to let it go first.
> 
> Thanks
it's still queued for next. not too late to drop or better add
a patch on top.

> >
> > Thanks.
> >