[PATCH net-next v2 0/2] netdev: expose page pool order via netlink

[PATCH net-next v2 0/2] netdev: expose page pool order via netlink

[Dragos Tatulea]

This small series exposes io_uring's high order page configuration
via the page_pool netlink interface and updates the appropriate
selftest to check this value.

---
v2:
- Switched from exposing page_pool order to rx_buf_len via nl_fill of
  the io_uring memory provider.
- Updated selftest to check rx_buf_len.
- v1: https://lore.kernel.org/all/20260611161235.3807332-1-dtatulea@nvidia.com/
---
Dragos Tatulea (2):
  netdev: expose io_uring rx_page_order order via netlink
  io_uring/zcrx: selftests: verify rx_buf_len for large chunks

 Documentation/netlink/specs/netdev.yaml       |  9 ++++++-
 include/uapi/linux/netdev.h                   |  2 ++
 io_uring/zcrx.c                               |  8 ++++++
 tools/include/uapi/linux/netdev.h             |  2 ++
 .../selftests/drivers/net/hw/iou-zcrx.py      | 26 ++++++++++++++++++-
 5 files changed, 45 insertions(+), 2 deletions(-)

-- 
2.54.0

[PATCH net-next v2 1/2] netdev: expose io_uring rx_page_order order via netlink

[Dragos Tatulea]

This adds observability for the io_uring zcrx rx-buf-len configuration.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Yael Chemla <ychemla@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
---
 Documentation/netlink/specs/netdev.yaml | 9 ++++++++-
 include/uapi/linux/netdev.h             | 2 ++
 io_uring/zcrx.c                         | 8 ++++++++
 tools/include/uapi/linux/netdev.h       | 2 ++
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index 49862b666d7d..5f143da7458c 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -127,7 +127,14 @@ attribute-sets:
         enum: xsk-flags
   -
     name: io-uring-provider-info
-    attributes: []
+    attributes:
+      -
+        name: rx-buf-len
+        type: uint
+        doc: |
+          RX buffer length in bytes for this io_uring memory provider.
+          Reflects the rx_buf_len passed at io_uring zerocopy rx
+          registration time.
   -
     name: page-pool
     attributes:
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index 7df1056a35fd..2f3ab75e8cc0 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -97,6 +97,8 @@ enum {
 };
 
 enum {
+	NETDEV_A_IO_URING_PROVIDER_INFO_RX_BUF_LEN = 1,
+
 	__NETDEV_A_IO_URING_PROVIDER_INFO_MAX,
 	NETDEV_A_IO_URING_PROVIDER_INFO_MAX = (__NETDEV_A_IO_URING_PROVIDER_INFO_MAX - 1)
 };
diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 19837e0b5e91..c7b167c2d4e4 100644
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -1156,6 +1156,7 @@ static void io_pp_zc_destroy(struct page_pool *pp)
 static int io_pp_nl_fill(void *mp_priv, struct sk_buff *rsp,
 			 struct netdev_rx_queue *rxq)
 {
+	struct io_zcrx_ifq *ifq = mp_priv;
 	struct nlattr *nest;
 	int type;
 
@@ -1163,6 +1164,13 @@ static int io_pp_nl_fill(void *mp_priv, struct sk_buff *rsp,
 	nest = nla_nest_start(rsp, type);
 	if (!nest)
 		return -EMSGSIZE;
+
+	if (nla_put_uint(rsp, NETDEV_A_IO_URING_PROVIDER_INFO_RX_BUF_LEN,
+			 1ULL << ifq->niov_shift)) {
+		nla_nest_cancel(rsp, nest);
+		return -EMSGSIZE;
+	}
+
 	nla_nest_end(rsp, nest);
 
 	return 0;
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index 7df1056a35fd..2f3ab75e8cc0 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -97,6 +97,8 @@ enum {
 };
 
 enum {
+	NETDEV_A_IO_URING_PROVIDER_INFO_RX_BUF_LEN = 1,
+
 	__NETDEV_A_IO_URING_PROVIDER_INFO_MAX,
 	NETDEV_A_IO_URING_PROVIDER_INFO_MAX = (__NETDEV_A_IO_URING_PROVIDER_INFO_MAX - 1)
 };
-- 
2.54.0

Re: [PATCH net-next v2 1/2] netdev: expose io_uring rx_page_order order via netlink

[Pavel Begunkov]

On 6/12/26 22:17, Dragos Tatulea wrote:
> This adds observability for the io_uring zcrx rx-buf-len configuration.

It might be nicer to look it up in the queue, e.g. rxq->mp_params,
and make it a queue attribute instead of zcrx specific one. In either
case, no objections.

Acked-by: Pavel Begunkov <asml.silence@gmail.com>

-- 
Pavel Begunkov

Re: [PATCH net-next v2 1/2] netdev: expose io_uring rx_page_order order via netlink

[Dragos Tatulea]

On 13.06.26 11:53, Pavel Begunkov wrote:
> On 6/12/26 22:17, Dragos Tatulea wrote:
>> This adds observability for the io_uring zcrx rx-buf-len configuration.
> 
> It might be nicer to look it up in the queue, e.g. rxq->mp_params,
> and make it a queue attribute instead of zcrx specific one. In either
> case, no objections.
> 
In io_pp_nl_fill() or in page_pool_nl_fill() as it was done in v1 for order?

Thanks,
Dragos

Re: [PATCH net-next v2 1/2] netdev: expose io_uring rx_page_order order via netlink

[Jakub Kicinski]

On Sat, 13 Jun 2026 16:09:03 +0200 Dragos Tatulea wrote:
> On 13.06.26 11:53, Pavel Begunkov wrote:
> > On 6/12/26 22:17, Dragos Tatulea wrote:  
> >> This adds observability for the io_uring zcrx rx-buf-len configuration.  
> > 
> > It might be nicer to look it up in the queue, e.g. rxq->mp_params,
> > and make it a queue attribute instead of zcrx specific one. In either
> > case, no objections.
>   
> In io_pp_nl_fill() or in page_pool_nl_fill() as it was done in v1 for order?

It's fine. We decided to make the "page size" a memory provider
property, now we're going back to making it a queue level param? 
Like my RFC had that everyone hated so much? Sigh.

Re: [PATCH net-next v2 1/2] netdev: expose io_uring rx_page_order order via netlink

[Pavel Begunkov]

On 6/14/26 01:02, Jakub Kicinski wrote:
> On Sat, 13 Jun 2026 16:09:03 +0200 Dragos Tatulea wrote:
>> On 13.06.26 11:53, Pavel Begunkov wrote:
>>> On 6/12/26 22:17, Dragos Tatulea wrote:
>>>> This adds observability for the io_uring zcrx rx-buf-len configuration.
>>>
>>> It might be nicer to look it up in the queue, e.g. rxq->mp_params,
>>> and make it a queue attribute instead of zcrx specific one. In either
>>> case, no objections.
>>    
>> In io_pp_nl_fill() or in page_pool_nl_fill() as it was done in v1 for order?
> 
> It's fine. We decided to make the "page size" a memory provider
> property, now we're going back to making it a queue level param?
> Like my RFC had that everyone hated so much? Sigh.

TBH, I never cared much how nl would show it, so not opposing either
version. My idea is that even without plumbing in per-queue non-mp size
configuration, it'd be nice to have a common way to check it b/w
providers.

 From the semantics and observability perspective, zcrx is probably not
that interesting as the parameter is basically just a hint with no affect
on uapi, and I'd assume people would rather see the page pool size or even
the NIC's page size. But I guess it depends on what Dragos is really after
with this patch.

-- 
Pavel Begunkov

Re: [PATCH net-next v2 1/2] netdev: expose io_uring rx_page_order order via netlink

[Jakub Kicinski]

On Mon, 15 Jun 2026 12:16:47 +0100 Pavel Begunkov wrote:
> On 6/14/26 01:02, Jakub Kicinski wrote:
> > On Sat, 13 Jun 2026 16:09:03 +0200 Dragos Tatulea wrote:  
> >> In io_pp_nl_fill() or in page_pool_nl_fill() as it was done in v1 for order?  
> > 
> > It's fine. We decided to make the "page size" a memory provider
> > property, now we're going back to making it a queue level param?
> > Like my RFC had that everyone hated so much? Sigh.  
> 
> TBH, I never cared much how nl would show it, so not opposing either
> version. My idea is that even without plumbing in per-queue non-mp size
> configuration, it'd be nice to have a common way to check it b/w
> providers.
> 
>  From the semantics and observability perspective, zcrx is probably not
> that interesting as the parameter is basically just a hint with no affect
> on uapi, and I'd assume people would rather see the page pool size or even
> the NIC's page size. But I guess it depends on what Dragos is really after
> with this patch.

Not sure what Dragos's use case is but IMO it's useful as system admin
/ vendor to be able to peek at the important params when user reports
bad perf. The netlink MP info is meant for system observability.

Re: [PATCH net-next v2 1/2] netdev: expose io_uring rx_page_order order via netlink

[Pavel Begunkov]

On 6/13/26 15:09, Dragos Tatulea wrote:
> On 13.06.26 11:53, Pavel Begunkov wrote:
>> On 6/12/26 22:17, Dragos Tatulea wrote:
>>> This adds observability for the io_uring zcrx rx-buf-len configuration.
>>
>> It might be nicer to look it up in the queue, e.g. rxq->mp_params,
>> and make it a queue attribute instead of zcrx specific one. In either
>> case, no objections.
>>
> In io_pp_nl_fill() or in page_pool_nl_fill() as it was done in v1 for order?

I didn't see v1, so yeah, I was thinking along the same lines as
your previous version. Oh, well

-- 
Pavel Begunkov

Re: [PATCH net-next v2 0/2] netdev: expose page pool order via netlink

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Sat, 13 Jun 2026 00:17:02 +0300 you wrote:
> This small series exposes io_uring's high order page configuration
> via the page_pool netlink interface and updates the appropriate
> selftest to check this value.
> 
> ---
> v2:
> - Switched from exposing page_pool order to rx_buf_len via nl_fill of
>   the io_uring memory provider.
> - Updated selftest to check rx_buf_len.
> - v1: https://lore.kernel.org/all/20260611161235.3807332-1-dtatulea@nvidia.com/
> 
> [...]

Here is the summary with links:
  - [net-next,v2,1/2] netdev: expose io_uring rx_page_order order via netlink
    https://git.kernel.org/netdev/net-next/c/5c4adb7fb46f
  - [net-next,v2,2/2] io_uring/zcrx: selftests: verify rx_buf_len for large chunks
    https://git.kernel.org/netdev/net-next/c/18f65355e112

You are awesome, thank you!
-- 
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