On Mon, Nov 22, 2021 at 05:28:31PM +0800, Wenpeng Liang wrote:
>
>
> On 2021/11/22 16:58, Leon Romanovsky wrote:
> >> entry = to_hns_mmap(rdma_entry);
> >> pfn = entry->address >> PAGE_SHIFT;
> >> - prot = vma->vm_page_prot;
> >>
> >> - if (entry->mmap_type != HNS_ROCE_MMAP_TYPE_TPTR)
> >> - prot = pgprot_noncached(prot);
> >> + switch (entry->mmap_type) {
> >> + case HNS_ROCE_MMAP_TYPE_DB:
> >> + prot = pgprot_noncached(vma->vm_page_prot);
> >> + break;
> >> + case HNS_ROCE_MMAP_TYPE_TPTR:
> >> + prot = vma->vm_page_prot;
> >> + break;
> >> + case HNS_ROCE_MMAP_TYPE_DWQE:
> >> + prot = pgprot_device(vma->vm_page_prot);
> > Everything fine, except this pgprot_device(). You probably need to check
> > WC internally in your driver and use or pgprot_writecombine() or
> > pgprot_noncached() explicitly.
> >
> > Thanks
> > .
> >
>
> This issue is also discussed in the v2 version, direct wqe uses
> this prot on HIP09 can achieve better performance than NC.
>
> v2 link: https://patchwork.kernel.org/project/linux-rdma/patch/1622705834-19353-3-git-send-email-liweihang@xxxxxxxxxx/
But isn't it specific to ARM model that behaves such? Will it be the case
when you move to upgrade your ARM core?
Thanks
>
> Thanks
> Wenpeng
