Re: [PATCH v3] page_pool: add a comment explaining the fragment counter usage

From: Ilias Apalodimas
Date: Tue Feb 21 2023 - 12:22:54 EST


On Tue, 21 Feb 2023 at 19:15, Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
>
> On Sat, 18 Feb 2023 00:21:30 +0200 Ilias Apalodimas wrote:
> > When reading the page_pool code the first impression is that keeping
> > two separate counters, one being the page refcnt and the other being
> > fragment pp_frag_count, is counter-intuitive.
> >
> > However without that fragment counter we don't know when to reliably
> > destroy or sync the outstanding DMA mappings. So let's add a comment
> > explaining this part.
>
> I discussed with Paolo off-list, since it's just a comment change
> I'll push it in.

Fair enough. Thanks Jakub.

Regards
/Ilias