On Wed, Feb 19, 2025 at 9:16 AM David Wei [off-list ref] wrote:

On 2024-11-01 11:24, Taehee Yoo wrote:

quoted

On Fri, Nov 1, 2024 at 11:53 PM Mina Almasry [off-list ref] wrote:

quoted

On Tue, Oct 22, 2024 at 9:25 AM Taehee Yoo [off-list ref] wrote:

quoted

Currently, bnxt_en driver satisfies the requirements of Device memory
TCP, which is tcp-data-split.
So, it implements Device memory TCP for bnxt_en driver.

From now on, the aggregation ring handles netmem_ref instead of page
regardless of the on/off of netmem.
So, for the aggregation ring, memory will be handled with the netmem
page_pool API instead of generic page_pool API.

If Devmem is enabled, netmem_ref is used as-is and if Devmem is not
enabled, netmem_ref will be converted to page and that is used.

Driver recognizes whether the devmem is set or unset based on the
mp_params.mp_priv is not NULL.
Only if devmem is set, it passes PP_FLAG_ALLOW_UNREADABLE_NETMEM.

Looks like in the latest version, you pass
PP_FLAG_ALLOW_UNREADABLE_NETMEM unconditionally, so this line is
obsolete.

Okay, I will remove this line.

quoted

However, I think you should only pass PP_FLAG_ALLOW_UNREADABLE_NETMEM
if hds_thresh==0 and tcp-data-split==1, because otherwise the driver
is not configured well enough to handle unreadable netmem, right? I
know that we added checks in the devmem binding to detect hds_thresh
and tcp-data-split, but we should keep another layer of protection in
the driver. The driver should not set PP_FLAG_ALLOW_UNREADABLE_NETMEM
unless it's configured to be able to handle unreadable netmem.

Okay, I agree, I will pass PP_FLAG_ALLOW_UNREADABLE_NETMEM
only when hds_thresh==0 and tcp-data-split==1.

quoted

quoted

Tested-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
---

v4:
 - Do not select NET_DEVMEM in Kconfig.
 - Pass PP_FLAG_ALLOW_UNREADABLE_NETMEM flag unconditionally.
 - Add __bnxt_rx_agg_pages_xdp().
 - Use gfp flag in __bnxt_alloc_rx_netmem().
 - Do not add *offset in the __bnxt_alloc_rx_netmem().
 - Do not pass queue_idx to bnxt_alloc_rx_page_pool().
 - Add Test tag from Stanislav.
 - Add page_pool_recycle_direct_netmem() helper.

v3:
 - Patch added.

 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 182 ++++++++++++++++------
 drivers/net/ethernet/broadcom/bnxt/bnxt.h |   2 +-
 include/net/page_pool/helpers.h           |   6 +
 3 files changed, 142 insertions(+), 48 deletions(-)

Hi Taehee, what is your plan with this patch? Are you still working on
it? I noticed that you dropped it in later versions of this series. With
io_uring zero copy Rx now merged I also need bnxt support, but I don't
want to duplicate efforts. Please let me know, thanks!

Hi David,
Sorry for the late! I'm still working on it.
I implemented a working patch, but there are several bugs.
So I'm thinking about how to deal with it.
And then, I would like to send this patch after fixing bugs.

Thanks a lot!
Taehee Yoo