Re: [PATCH for-next 4/6] RDMA/hns: Support flexible pagesize

[Junxian Huang]

On 2023/12/26 16:52, Leon Romanovsky wrote:
> On Mon, Dec 25, 2023 at 03:53:28PM +0800, Junxian Huang wrote:
>> From: Chengchang Tang <tangchengchang@xxxxxxxxxx>
>>
>> In the current implementation, a fixed page size is used to
>> configure the PBL, which is not flexible enough and is not
>> conducive to the performance of the HW.
>>
>> Signed-off-by: Chengchang Tang <tangchengchang@xxxxxxxxxx>
>> Signed-off-by: Junxian Huang <huangjunxian6@xxxxxxxxxxxxx>
>> ---
>>  drivers/infiniband/hw/hns/hns_roce_alloc.c  |   6 -
>>  drivers/infiniband/hw/hns/hns_roce_device.h |   9 ++
>>  drivers/infiniband/hw/hns/hns_roce_mr.c     | 168 +++++++++++++++-----
>>  3 files changed, 139 insertions(+), 44 deletions(-)
> 
> I'm wonder if the ib_umem_find_best_pgsz() API should be used instead.
> What is missing there?
> 
> Thanks

Actually this API is used for umem.
For kmem, we add hns_roce_find_buf_best_pgsz() to do a similar job.

+static int get_best_page_shift(struct hns_roce_dev *hr_dev,
+			       struct hns_roce_mtr *mtr,
+			       struct hns_roce_buf_attr *buf_attr)
+{
+	unsigned int page_sz;
+
+	if (!buf_attr->adaptive || buf_attr->type != MTR_PBL)
+		return 0;
+
+	if (mtr->umem)
+		page_sz = ib_umem_find_best_pgsz(mtr->umem,
+						 hr_dev->caps.page_size_cap,
+						 buf_attr->iova);
+	else
+		page_sz = hns_roce_find_buf_best_pgsz(hr_dev, mtr->kmem);
+
+	if (!page_sz)
+		return -EINVAL;
+
+	buf_attr->page_shift = order_base_2(page_sz);
+	return 0;
+}

Thanks,
Junxian