Re: [PATCH net-next v6 3/5] page_pool: Allow drivers to hint on SKB recycling

[David Ahern]

On 6/4/21 2:42 AM, Ilias Apalodimas wrote:
> [...]
>>> +	/* Driver set this to memory recycling info. Reset it on recycle.
>>> +	 * This will *not* work for NIC using a split-page memory model.
>>> +	 * The page will be returned to the pool here regardless of the
>>> +	 * 'flipped' fragment being in use or not.
>>> +	 */
>>
>> I am not sure I understand how does the last part of comment related
>> to the code below, as there is no driver using split-page memory model
>> will reach here because those driver will not call skb_mark_for_recycle(),
>> right?
>>
> 
> Yes the comment is there to prohibit people (mlx5 only actually) to add the
> recycling bit on their driver.  Because if they do it will *probably* work
> but they might get random corrupted packets which will be hard to debug.
> 

What's the complexity for getting it to work with split page model?
Since 1500 is the default MTU, requiring a page per packet means a lot
of wasted memory.