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Date: Fri, 16 Jun 2023 12:21:40 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Jesper Dangaard Brouer <jbrouer@redhat.com>
Cc: Alexander Duyck <alexander.duyck@gmail.com>, Yunsheng Lin
 <linyunsheng@huawei.com>, brouer@redhat.com, davem@davemloft.net,
 pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
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 <yisen.zhuang@huawei.com>, Salil Mehta <salil.mehta@huawei.com>, Eric
 Dumazet <edumazet@google.com>, Sunil Goutham <sgoutham@marvell.com>, Geetha
 sowjanya <gakula@marvell.com>, Subbaraya Sundeep <sbhatta@marvell.com>,
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Subject: Re: [PATCH net-next v4 4/5] page_pool: remove PP_FLAG_PAGE_FRAG
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On Fri, 16 Jun 2023 20:59:12 +0200 Jesper Dangaard Brouer wrote:
> +       if (mem_type == MEM_TYPE_PP_NETMEM)
> +               pp_netmem_put_page(pp, page, allow_direct);
> +       else
> +               page_pool_put_full_page(pp, page, allow_direct);

Interesting, what is the netmem type? I was thinking about extending
page pool for other mem providers and what came to mind was either
optionally replacing the free / alloc with a function pointer:

https://github.com/torvalds/linux/commit/578ebda5607781c0abb26c1feae7ec8b83840768

or wrapping the PP calls with static inlines which can direct to 
a different implementation completely (like zctap / io_uring zc).

Former is better for huge pages, latter is better for IO mem
(peer-to-peer DMA). I wonder if you have different use case which
requires a different model :(