Re: [PATCH net-next 1/3] net: netmem: add net_iov_area freelist helpers

[Pavel Begunkov <asml.silence@gmail.com>]

On 9/24/26 17:46, Mina Almasry wrote:
> On Thu, Sep 24, 2026 at 8:41 AM Pavel Begunkov <asml.silence@gmail.com> wrote:
>>
>> On 9/24/26 16:02, Mina Almasry wrote:
>>> On Tue, Sep 22, 2026 at 1:43 PM Stanislav Fomichev <sdf.kernel@gmail.com> wrote:
>>>>
>>>> io_uring zero-copy receive and devmem both maintain a bounded LIFO for
>>>> net_iovs in a contiguous area. Store the freelist in struct net_iov_area
>>>> and provide common push and pop helpers.
>>>>
>>>> Leave synchronization to area owners. Keep devmem's area adjacent to its
>>>
>>> This could be a follow up change, but I think synchronization should
>>> be provided by the netmem/niov infra, rather than the area owners. TBH
>>> the infra providing an unsynchronized data structure and letting the
>>> area owner use it and shoot themselves in the foot feels error prone.
>>> For now we could use a comment.
>>
>> I don't think we want it. The duplication is minor, but I'm not set
>> on the per area index array approach, and it'd make changing it
>> more difficult.
>>
> 
> What is 'it'? I'm guessing you don't want the freelist array put in
> the net_iov_area at all then? Because even that change will make
> replacing the freelist array hard to swap? Or are you objecting to
> just letting the netmem functions do the locking
I meant this consolidation / patch. Yes, it adds more friction
but I don't see much benefit. And I can guess why Stan didn't
include locking, zcrx takes it for additional sync and keeps
one lock for all areas.

-- 
Pavel Begunkov