netdev - Re: [RFC] shrinking struct page (part of page pool)

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Message-ID: <CAC_iWjKr-Jd7DsAameimUYPUPgu8vBrsFb0cDJiNSBLEwqKF1A@mail.gmail.com>
Date: Sat, 10 May 2025 10:02:59 +0300
From: Ilias Apalodimas <ilias.apalodimas@...aro.org>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Byungchul Park <byungchul@...com>, willy@...radead.org, almasrymina@...gle.com, 
	kernel_team@...ynix.com, 42.hyeyoo@...il.com, linux-mm@...ck.org, 
	hawk@...nel.org, netdev@...r.kernel.org
Subject: Re: [RFC] shrinking struct page (part of page pool)

Hi Jakub

[...]

> > >
> > >    struct bump {
> > >     unsigned long _page_flags;
> > >     unsigned long bump_magic;
> > >     struct page_pool *bump_pp;
> > >     unsigned long _pp_mapping_pad;
> > >     unsigned long dma_addr;
> > >     atomic_long_t bump_ref_count;
> > >     unsigned int _page_type;
> > >     atomic_t _refcount;
> > >    };
> > >
> > > To netwrok guys, any thoughts on it?
> > > To Willy, do I understand correctly your direction?
> > >
> > > Plus, it's a quite another issue but I'm curious, that is, what do you
> > > guys think about moving the bump allocator(= page pool) code from
> > > network to mm?  I'd like to start on the work once gathering opinion
> > > from both Willy and network guys.
>
> I don't see any benefit from moving page pool to MM. It is quite
> networking specific. But we can discuss this later. Moving code
> is trivial, it should not be the initial focus.

Random thoughts here until I look at the patches.
The concept of devices doing DMA + recycling the used buffer
transcends networking. But I agree with you, that's something we can
discuss on the reviews.

Thanks
/Ilias