From: David Ahern <dsahern@kernel.org>
To: Yunsheng Lin <linyunsheng@huawei.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Mina Almasry <almasrymina@google.com>
Cc: "Jakub Kicinski" <kuba@kernel.org>,
davem@davemloft.net, pabeni@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
"Willem de Bruijn" <willemb@google.com>,
"Kaiyuan Zhang" <kaiyuanz@google.com>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Eric Dumazet" <edumazet@google.com>,
"Christian König" <christian.koenig@amd.com>,
"Matthew Wilcox" <willy@infradead.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH RFC 3/8] memory-provider: dmabuf devmem memory provider
Date: Wed, 15 Nov 2023 10:57:30 -0700 [thread overview]
Message-ID: <ee10d050-ef24-49b2-8712-c9bc8a911c2a@kernel.org> (raw)
In-Reply-To: <ed875644-95e8-629a-4c28-bf42329efa56@huawei.com>
On 11/15/23 2:21 AM, Yunsheng Lin wrote:
> On 2023/11/14 21:16, Jason Gunthorpe wrote:
>> On Tue, Nov 14, 2023 at 04:21:26AM -0800, Mina Almasry wrote:
>>
>>> Actually because you put the 'strtuct page for devmem' in
>>> skb->bv_frag, the net stack will grab the 'struct page' for devmem
>>> using skb_frag_page() then call things like page_address(), kmap,
>>> get_page, put_page, etc, etc, etc.
>>
>> Yikes, please no. If net has its own struct page look alike it has to
>> stay entirely inside net. A non-mm owned struct page should not be
>> passed into mm calls. It is just way too hacky to be seriously
>> considered :(
>
> Yes, that is something this patchset is trying to do, defining its own
> struct page look alike for page pool to support devmem.
>
Networking needs to be able to move away from struct page references.
The devmem and host memory for Rx use cases do not need to be page based.
next prev parent reply other threads:[~2023-11-15 17:57 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20231113130041.58124-1-linyunsheng@huawei.com>
[not found] ` <20231113130041.58124-4-linyunsheng@huawei.com>
[not found] ` <CAHS8izMjmj0DRT_vjzVq5HMQyXtZdVK=o4OP0gzbaN=aJdQ3ig@mail.gmail.com>
[not found] ` <20231113180554.1d1c6b1a@kernel.org>
2023-11-14 8:23 ` Yunsheng Lin
2023-11-14 12:21 ` Mina Almasry
2023-11-14 12:49 ` Yunsheng Lin
2023-11-14 12:58 ` Mina Almasry
2023-11-14 13:19 ` Yunsheng Lin
2023-11-14 15:41 ` Willem de Bruijn
2023-11-15 9:29 ` Yunsheng Lin
2023-11-15 18:07 ` Mina Almasry
2023-11-15 19:05 ` Mina Almasry
2023-11-16 11:12 ` Yunsheng Lin
2023-11-16 11:30 ` Mina Almasry
2023-11-14 13:16 ` Jason Gunthorpe
2023-11-15 6:46 ` Christian König
2023-11-15 9:21 ` Yunsheng Lin
2023-11-15 13:38 ` Jason Gunthorpe
2023-11-16 11:10 ` Yunsheng Lin
2023-11-16 15:31 ` Jason Gunthorpe
2023-11-15 17:44 ` Mina Almasry
2023-11-16 11:11 ` Yunsheng Lin
2023-11-15 17:57 ` David Ahern [this message]
2023-11-16 11:12 ` Yunsheng Lin
2023-11-16 15:58 ` David Ahern
2023-11-17 11:27 ` Yunsheng Lin
2023-11-14 22:25 ` Jakub Kicinski
2023-11-15 9:33 ` Yunsheng Lin
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