Re: [PATCH net-next v5 03/14] page_pool: avoid calling no-op externals when possible

[Alexander Lobakin]

From: Jakub Kicinski <kuba@xxxxxxxxxx>
Date: Mon, 27 Nov 2023 10:17:20 -0800

> On Mon, 27 Nov 2023 15:32:19 +0100 Alexander Lobakin wrote:
>>> Sorry for not remembering the suggestion:(  
>>
>> In the previous versions of this change I used a global flag per whole
>> page_pool, just like XSk does for the whole XSk buff pool, then you
>> proposed to use the lowest bit of ::dma_addr and store it per page, so
>> that it would be more granular/precise. I tested it and it doesn't
>> perform worse than global, but in some cases may be beneficial.
> 
> FWIW I'd vote to stick to per-page pool. You seem to handle the
> sizeof(dma_addr_t) > sizeof(long) case correctly but the code is
> growing in complexity, providing no known/measurable benefit.
> We can always do this later but for now it seems like a premature
> optimization to me.

Yeah, this also seems more logical and optimal to me. Will wait a bit
for a possible reply from Chris and then send the next rev.

Thanks,
Olek