From: David Wei <dw@davidwei.uk>
To: David Ahern <dsahern@kernel.org>, Mina Almasry <almasrymina@google.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Arnd Bergmann" <arnd@arndb.de>,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
"Shuah Khan" <shuah@kernel.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
"Shakeel Butt" <shakeelb@google.com>,
"Jeroen de Borst" <jeroendb@google.com>,
"Praveen Kaligineedi" <pkaligineedi@google.com>,
"Willem de Bruijn" <willemb@google.com>,
"Kaiyuan Zhang" <kaiyuanz@google.com>,
"Pavel Begunkov" <asml.silence@gmail.com>
Subject: Re: [RFC PATCH v3 05/12] netdev: netdevice devmem allocator
Date: Wed, 8 Nov 2023 17:00:39 -0800 [thread overview]
Message-ID: <b1476f8e-1b4b-497a-9e80-aff679ca8b4b@davidwei.uk> (raw)
In-Reply-To: <a5b95e6b-8716-4e2e-9183-959b754b5b5e@kernel.org>
On 2023-11-07 14:55, David Ahern wrote:
> On 11/7/23 3:10 PM, Mina Almasry wrote:
>> On Mon, Nov 6, 2023 at 3:44 PM David Ahern <dsahern@kernel.org> wrote:
>>>
>>> On 11/5/23 7:44 PM, Mina Almasry wrote:
>>>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>>>> index eeeda849115c..1c351c138a5b 100644
>>>> --- a/include/linux/netdevice.h
>>>> +++ b/include/linux/netdevice.h
>>>> @@ -843,6 +843,9 @@ struct netdev_dmabuf_binding {
>>>> };
>>>>
>>>> #ifdef CONFIG_DMA_SHARED_BUFFER
>>>> +struct page_pool_iov *
>>>> +netdev_alloc_devmem(struct netdev_dmabuf_binding *binding);
>>>> +void netdev_free_devmem(struct page_pool_iov *ppiov);
>>>
>>> netdev_{alloc,free}_dmabuf?
>>>
>>
>> Can do.
>>
>>> I say that because a dmabuf can be host memory, at least I am not aware
>>> of a restriction that a dmabuf is device memory.
>>>
>>
>> In my limited experience dma-buf is generally device memory, and
>> that's really its use case. CONFIG_UDMABUF is a driver that mocks
>> dma-buf with a memfd which I think is used for testing. But I can do
>> the rename, it's more clear anyway, I think.
>
> config UDMABUF
> bool "userspace dmabuf misc driver"
> default n
> depends on DMA_SHARED_BUFFER
> depends on MEMFD_CREATE || COMPILE_TEST
> help
> A driver to let userspace turn memfd regions into dma-bufs.
> Qemu can use this to create host dmabufs for guest framebuffers.
>
>
> Qemu is just a userspace process; it is no way a special one.
>
> Treating host memory as a dmabuf should radically simplify the io_uring
> extension of this set. That the io_uring set needs to dive into
> page_pools is just wrong - complicating the design and code and pushing
> io_uring into a realm it does not need to be involved in.
I think our io_uring proposal will already be vastly simplified once we
rebase onto Kuba's page pool memory provider API. Using udmabuf means
depending on a driver designed for testing, vs io_uring's registered
buffers API that's been tried and tested.
I don't have an intuitive understanding of the trade offs yet, and would
need to try out udmabuf and compare vs say using our own page pool
memory provider.
>
> Most (all?) of this patch set can work with any memory; only device
> memory is unreadable.
>
>
next prev parent reply other threads:[~2023-11-09 1:00 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-06 2:43 [RFC PATCH v3 00/12] Device Memory TCP Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 01/12] net: page_pool: factor out releasing DMA from releasing the page Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 02/12] net: page_pool: create hooks for custom page providers Mina Almasry
2023-11-07 7:44 ` Yunsheng Lin
2023-11-09 11:09 ` Paolo Abeni
2023-11-10 23:19 ` Jakub Kicinski
2023-11-13 3:28 ` Mina Almasry
2023-11-13 22:10 ` Jakub Kicinski
2023-11-06 2:44 ` [RFC PATCH v3 03/12] net: netdev netlink api to bind dma-buf to a net device Mina Almasry
2023-11-10 23:16 ` Jakub Kicinski
2023-11-06 2:44 ` [RFC PATCH v3 04/12] netdev: support binding dma-buf to netdevice Mina Almasry
2023-11-07 7:46 ` Yunsheng Lin
2023-11-07 21:59 ` Mina Almasry
2023-11-08 3:40 ` Yunsheng Lin
2023-11-09 2:22 ` Mina Almasry
2023-11-09 9:29 ` Yunsheng Lin
2023-11-08 23:47 ` David Wei
2023-11-09 2:25 ` Mina Almasry
2023-11-09 8:29 ` Paolo Abeni
2023-11-10 2:59 ` Mina Almasry
2023-11-10 7:38 ` Yunsheng Lin
2023-11-10 9:45 ` Mina Almasry
2023-11-10 23:19 ` Jakub Kicinski
2023-11-11 2:19 ` Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 05/12] netdev: netdevice devmem allocator Mina Almasry
2023-11-06 23:44 ` David Ahern
2023-11-07 22:10 ` Mina Almasry
2023-11-07 22:55 ` David Ahern
2023-11-07 23:03 ` Mina Almasry
2023-11-09 1:15 ` David Wei
2023-11-10 14:26 ` Pavel Begunkov
2023-11-11 17:19 ` David Ahern
2023-11-14 16:09 ` Pavel Begunkov
2023-11-09 1:00 ` David Wei [this message]
2023-11-08 3:48 ` Yunsheng Lin
2023-11-09 1:41 ` Mina Almasry
2023-11-07 7:45 ` Yunsheng Lin
2023-11-09 8:44 ` Paolo Abeni
2023-11-06 2:44 ` [RFC PATCH v3 06/12] memory-provider: dmabuf devmem memory provider Mina Almasry
2023-11-06 21:02 ` Stanislav Fomichev
2023-11-06 23:49 ` David Ahern
2023-11-08 0:02 ` Mina Almasry
2023-11-08 0:10 ` David Ahern
2023-11-10 23:16 ` Jakub Kicinski
2023-11-13 4:54 ` Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 07/12] page-pool: device memory support Mina Almasry
2023-11-07 8:00 ` Yunsheng Lin
2023-11-07 21:56 ` Mina Almasry
2023-11-08 10:56 ` Yunsheng Lin
2023-11-09 3:20 ` Mina Almasry
2023-11-09 9:30 ` Yunsheng Lin
2023-11-09 12:20 ` Mina Almasry
2023-11-09 13:23 ` Yunsheng Lin
2023-11-09 9:01 ` Paolo Abeni
2023-11-06 2:44 ` [RFC PATCH v3 08/12] net: support non paged skb frags Mina Almasry
2023-11-07 9:00 ` Yunsheng Lin
2023-11-07 21:19 ` Mina Almasry
2023-11-08 11:25 ` Yunsheng Lin
2023-11-09 9:14 ` Paolo Abeni
2023-11-10 4:06 ` Mina Almasry
2023-11-10 23:19 ` Jakub Kicinski
2023-11-13 6:05 ` Mina Almasry
2023-11-13 22:17 ` Jakub Kicinski
2023-11-06 2:44 ` [RFC PATCH v3 09/12] net: add support for skbs with unreadable frags Mina Almasry
2023-11-06 18:47 ` Stanislav Fomichev
2023-11-06 19:34 ` David Ahern
2023-11-06 20:31 ` Mina Almasry
2023-11-06 21:59 ` Stanislav Fomichev
2023-11-06 22:18 ` Mina Almasry
2023-11-06 22:59 ` Stanislav Fomichev
2023-11-06 23:27 ` Mina Almasry
2023-11-06 23:55 ` Stanislav Fomichev
2023-11-07 0:07 ` Willem de Bruijn
2023-11-07 0:14 ` Stanislav Fomichev
2023-11-07 0:59 ` Stanislav Fomichev
2023-11-07 2:23 ` Willem de Bruijn
2023-11-07 17:44 ` Stanislav Fomichev
2023-11-07 17:57 ` Willem de Bruijn
2023-11-07 18:14 ` Stanislav Fomichev
2023-11-07 0:20 ` Mina Almasry
2023-11-07 1:06 ` Stanislav Fomichev
2023-11-07 19:53 ` Mina Almasry
2023-11-07 21:05 ` Stanislav Fomichev
2023-11-07 21:17 ` Eric Dumazet
2023-11-07 22:23 ` Stanislav Fomichev
2023-11-10 23:17 ` Jakub Kicinski
2023-11-10 23:19 ` Jakub Kicinski
2023-11-07 1:09 ` David Ahern
2023-11-06 23:37 ` David Ahern
2023-11-07 0:03 ` Mina Almasry
2023-11-06 20:56 ` Stanislav Fomichev
2023-11-07 0:16 ` David Ahern
2023-11-07 0:23 ` Mina Almasry
2023-11-08 14:43 ` David Laight
2023-11-06 2:44 ` [RFC PATCH v3 10/12] tcp: RX path for devmem TCP Mina Almasry
2023-11-06 18:44 ` Stanislav Fomichev
2023-11-06 19:29 ` Mina Almasry
2023-11-06 21:14 ` Willem de Bruijn
2023-11-06 22:34 ` Stanislav Fomichev
2023-11-06 22:55 ` Willem de Bruijn
2023-11-06 23:32 ` Stanislav Fomichev
2023-11-06 23:55 ` David Ahern
2023-11-07 0:02 ` Willem de Bruijn
2023-11-07 23:55 ` Mina Almasry
2023-11-08 0:01 ` David Ahern
2023-11-09 2:39 ` Mina Almasry
2023-11-09 16:07 ` Edward Cree
2023-12-08 20:12 ` Pavel Begunkov
2023-11-09 11:05 ` Paolo Abeni
2023-11-10 23:16 ` Jakub Kicinski
2023-12-08 20:28 ` Pavel Begunkov
2023-12-08 20:09 ` Pavel Begunkov
2023-11-06 21:17 ` Stanislav Fomichev
2023-11-08 15:36 ` Edward Cree
2023-11-09 10:52 ` Paolo Abeni
2023-11-10 23:19 ` Jakub Kicinski
2023-11-06 2:44 ` [RFC PATCH v3 11/12] net: add SO_DEVMEM_DONTNEED setsockopt to release RX pages Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 12/12] selftests: add ncdevmem, netcat for devmem TCP Mina Almasry
2023-11-09 11:03 ` Paolo Abeni
2023-11-10 23:13 ` Jakub Kicinski
2023-11-11 2:27 ` Mina Almasry
2023-11-11 2:35 ` Jakub Kicinski
2023-11-13 4:08 ` Mina Almasry
2023-11-13 22:20 ` Jakub Kicinski
2023-11-10 23:17 ` Jakub Kicinski
2023-11-07 15:18 ` [RFC PATCH v3 00/12] Device Memory TCP David Ahern
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