On Tue, Aug 15, 2023 at 5:40 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, 15 Aug 2023 15:50:23 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> > On Tue, Aug 15, 2023 at 2:32 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> 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.
Nope, see this:
if (SKB_FRAG_PAGE_ORDER &&
!static_branch_unlikely(&net_high_order_alloc_disable_key)) {
/* Avoid direct reclaim but allow kswapd to wake */
pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
__GFP_COMP | __GFP_NOWARN |
__GFP_NORETRY,
SKB_FRAG_PAGE_ORDER);
if (likely(pfrag->page)) {
pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
return true;
}
}
The comp page might be disabled due to the SKB_FRAG_PAGE_ORDER and
net_high_order_alloc_disable_key.
>
>
> > 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.
Yes, we can optimize this on top.
Thanks
>
> Thanks.
>
> >
> > I see Michael has merge this series so I'm fine to let it go first.
> >
> > Thanks
> >
> > >
> > > Thanks.
> > >
> >
>
