From: Mina Almasry <almasrymina@google.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: "Shailend Chand" <shailend@google.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, linux-arch@vger.kernel.org,
linux-kselftest@vger.kernel.org, bpf@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>,
"Jonathan Corbet" <corbet@lwn.net>,
"Jeroen de Borst" <jeroendb@google.com>,
"Praveen Kaligineedi" <pkaligineedi@google.com>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Arnd Bergmann" <arnd@arndb.de>,
"David Ahern" <dsahern@kernel.org>,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
"Shuah Khan" <shuah@kernel.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
"Yunsheng Lin" <linyunsheng@huawei.com>,
"Harshitha Ramamurthy" <hramamurthy@google.com>,
"Shakeel Butt" <shakeelb@google.com>,
"Willem de Bruijn" <willemb@google.com>,
"Kaiyuan Zhang" <kaiyuanz@google.com>,
"Christoph Hellwig" <hch@infradead.org>
Subject: Re: [net-next v1 08/16] memory-provider: dmabuf devmem memory provider
Date: Tue, 12 Dec 2023 06:26:51 -0800 [thread overview]
Message-ID: <CAHS8izMVMx0fpT=dWsnD7piqs1g7Fam8Xf5dK3iOFNxeOQD9vQ@mail.gmail.com> (raw)
In-Reply-To: <20231212122535.GA3029808@nvidia.com>
On Tue, Dec 12, 2023 at 4:25 AM Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> On Thu, Dec 07, 2023 at 04:52:39PM -0800, Mina Almasry wrote:
>
> > +static inline struct page_pool_iov *page_to_page_pool_iov(struct page *page)
> > +{
> > + if (page_is_page_pool_iov(page))
> > + return (struct page_pool_iov *)((unsigned long)page & ~PP_IOV);
> > +
> > + DEBUG_NET_WARN_ON_ONCE(true);
> > + return NULL;
> > +}
>
> We already asked not to do this, please do not allocate weird things
> can call them 'struct page' when they are not. It undermines the
> maintainability of the mm to have things mis-typed like
> this. Introduce a new type for your thing so the compiler can check it
> properly.
>
There is a new type introduced, it's the page_pool_iov. We set the LSB
on page_pool_iov* and cast it to page* only to avoid the churn of
renaming page* to page_pool_iov* in the page_pool and all the net
drivers using it. Is that not a reasonable compromise in your opinion?
Since the LSB is set on the resulting page pointers, they are not
actually usuable as pages, and are never passed to mm APIs per your
requirement.
--
Thanks,
Mina
WARNING: multiple messages have this Message-ID (diff)
From: Mina Almasry <almasrymina@google.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: linux-doc@vger.kernel.org, "Kaiyuan Zhang" <kaiyuanz@google.com>,
dri-devel@lists.freedesktop.org,
"Eric Dumazet" <edumazet@google.com>,
linux-kselftest@vger.kernel.org, "Shuah Khan" <shuah@kernel.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
linux-arch@vger.kernel.org,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
"Jeroen de Borst" <jeroendb@google.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Christoph Hellwig" <hch@infradead.org>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
linux-media@vger.kernel.org,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"Arnd Bergmann" <arnd@arndb.de>,
"Shailend Chand" <shailend@google.com>,
"Shakeel Butt" <shakeelb@google.com>,
"Harshitha Ramamurthy" <hramamurthy@google.com>,
"Willem de Bruijn" <willemb@google.com>,
netdev@vger.kernel.org, "David Ahern" <dsahern@kernel.org>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
linux-kernel@vger.kernel.org,
"Christian König" <christian.koenig@amd.com>,
"Yunsheng Lin" <linyunsheng@huawei.com>,
"Praveen Kaligineedi" <pkaligineedi@google.com>,
bpf@vger.kernel.org, "David S. Miller" <davem@davemloft.net>
Subject: Re: [net-next v1 08/16] memory-provider: dmabuf devmem memory provider
Date: Tue, 12 Dec 2023 06:26:51 -0800 [thread overview]
Message-ID: <CAHS8izMVMx0fpT=dWsnD7piqs1g7Fam8Xf5dK3iOFNxeOQD9vQ@mail.gmail.com> (raw)
In-Reply-To: <20231212122535.GA3029808@nvidia.com>
On Tue, Dec 12, 2023 at 4:25 AM Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> On Thu, Dec 07, 2023 at 04:52:39PM -0800, Mina Almasry wrote:
>
> > +static inline struct page_pool_iov *page_to_page_pool_iov(struct page *page)
> > +{
> > + if (page_is_page_pool_iov(page))
> > + return (struct page_pool_iov *)((unsigned long)page & ~PP_IOV);
> > +
> > + DEBUG_NET_WARN_ON_ONCE(true);
> > + return NULL;
> > +}
>
> We already asked not to do this, please do not allocate weird things
> can call them 'struct page' when they are not. It undermines the
> maintainability of the mm to have things mis-typed like
> this. Introduce a new type for your thing so the compiler can check it
> properly.
>
There is a new type introduced, it's the page_pool_iov. We set the LSB
on page_pool_iov* and cast it to page* only to avoid the churn of
renaming page* to page_pool_iov* in the page_pool and all the net
drivers using it. Is that not a reasonable compromise in your opinion?
Since the LSB is set on the resulting page pointers, they are not
actually usuable as pages, and are never passed to mm APIs per your
requirement.
--
Thanks,
Mina
next prev parent reply other threads:[~2023-12-12 14:27 UTC|newest]
Thread overview: 145+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-08 0:52 [net-next v1 00/16] Device Memory TCP Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 0:52 ` [net-next v1 01/16] net: page_pool: factor out releasing DMA from releasing the page Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-10 3:49 ` Shakeel Butt
2023-12-10 3:49 ` Shakeel Butt
2023-12-12 8:11 ` Ilias Apalodimas
2023-12-12 8:11 ` Ilias Apalodimas
2023-12-08 0:52 ` [net-next v1 02/16] net: page_pool: create hooks for custom page providers Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-12 8:07 ` Ilias Apalodimas
2023-12-12 8:07 ` Ilias Apalodimas
2023-12-12 14:47 ` Mina Almasry
2023-12-12 14:47 ` Mina Almasry
2023-12-08 0:52 ` [net-next v1 03/16] queue_api: define queue api Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-14 1:15 ` Jakub Kicinski
2023-12-14 1:15 ` Jakub Kicinski
2023-12-08 0:52 ` [net-next v1 04/16] gve: implement " Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2024-03-05 11:45 ` Arnd Bergmann
2023-12-08 0:52 ` [net-next v1 05/16] net: netdev netlink api to bind dma-buf to a net device Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-14 1:17 ` Jakub Kicinski
2023-12-14 1:17 ` Jakub Kicinski
2023-12-08 0:52 ` [net-next v1 06/16] netdev: support binding dma-buf to netdevice Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 15:40 ` kernel test robot
2023-12-08 15:40 ` kernel test robot
2023-12-08 16:02 ` kernel test robot
2023-12-08 16:02 ` kernel test robot
2023-12-08 17:48 ` David Ahern
2023-12-08 17:48 ` David Ahern
2023-12-08 19:22 ` Mina Almasry
2023-12-08 19:22 ` Mina Almasry
2023-12-08 20:32 ` Mina Almasry
2023-12-08 20:32 ` Mina Almasry
2023-12-09 23:29 ` David Ahern
2023-12-09 23:29 ` David Ahern
2023-12-11 2:19 ` Mina Almasry
2023-12-11 2:19 ` Mina Almasry
2023-12-08 0:52 ` [net-next v1 07/16] netdev: netdevice devmem allocator Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 17:56 ` David Ahern
2023-12-08 17:56 ` David Ahern
2023-12-08 19:27 ` Mina Almasry
2023-12-08 19:27 ` Mina Almasry
2023-12-08 0:52 ` [net-next v1 08/16] memory-provider: dmabuf devmem memory provider Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 22:48 ` Pavel Begunkov
2023-12-08 22:48 ` Pavel Begunkov
2023-12-08 23:25 ` Mina Almasry
2023-12-08 23:25 ` Mina Almasry
2023-12-10 3:03 ` Pavel Begunkov
2023-12-10 3:03 ` Pavel Begunkov
2023-12-11 2:30 ` Mina Almasry
2023-12-11 2:30 ` Mina Almasry
2023-12-11 20:35 ` Pavel Begunkov
2023-12-11 20:35 ` Pavel Begunkov
2023-12-14 20:03 ` Mina Almasry
2023-12-14 20:03 ` Mina Almasry
2023-12-19 23:55 ` Pavel Begunkov
2023-12-19 23:55 ` Pavel Begunkov
2023-12-08 23:05 ` Pavel Begunkov
2023-12-08 23:05 ` Pavel Begunkov
2023-12-12 12:25 ` Jason Gunthorpe
2023-12-12 12:25 ` Jason Gunthorpe
2023-12-12 13:07 ` Christoph Hellwig
2023-12-12 14:26 ` Mina Almasry [this message]
2023-12-12 14:26 ` Mina Almasry
2023-12-12 14:39 ` Jason Gunthorpe
2023-12-12 14:39 ` Jason Gunthorpe
2023-12-12 14:58 ` Mina Almasry
2023-12-12 14:58 ` Mina Almasry
2023-12-12 15:08 ` Jason Gunthorpe
2023-12-12 15:08 ` Jason Gunthorpe
2023-12-13 1:09 ` Mina Almasry
2023-12-13 1:09 ` Mina Almasry
2023-12-13 2:19 ` David Ahern
2023-12-13 2:19 ` David Ahern
2023-12-13 7:49 ` Yinjun Zhang
2023-12-13 7:49 ` Yinjun Zhang
2023-12-08 0:52 ` [net-next v1 09/16] page_pool: device memory support Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 9:30 ` Yunsheng Lin
2023-12-08 9:30 ` Yunsheng Lin
2023-12-08 16:05 ` Mina Almasry
2023-12-08 16:05 ` Mina Almasry
2023-12-11 2:04 ` Yunsheng Lin
2023-12-11 2:04 ` Yunsheng Lin
2023-12-11 2:26 ` Mina Almasry
2023-12-11 2:26 ` Mina Almasry
2023-12-11 4:04 ` Mina Almasry
2023-12-11 4:04 ` Mina Almasry
2023-12-11 11:51 ` Yunsheng Lin
2023-12-11 11:51 ` Yunsheng Lin
2023-12-11 18:14 ` Mina Almasry
2023-12-11 18:14 ` Mina Almasry
2023-12-12 11:17 ` Yunsheng Lin
2023-12-12 11:17 ` Yunsheng Lin
2023-12-12 14:28 ` Mina Almasry
2023-12-12 14:28 ` Mina Almasry
2023-12-13 11:48 ` Yunsheng Lin
2023-12-13 11:48 ` Yunsheng Lin
2023-12-13 7:52 ` Mina Almasry
2023-12-13 7:52 ` Mina Almasry
2023-12-08 0:52 ` [net-next v1 10/16] page_pool: don't release iov on elevanted refcount Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 0:52 ` [net-next v1 11/16] net: support non paged skb frags Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 0:52 ` [net-next v1 12/16] net: add support for skbs with unreadable frags Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 0:52 ` [net-next v1 13/16] tcp: RX path for devmem TCP Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 15:40 ` kernel test robot
2023-12-08 15:40 ` kernel test robot
2023-12-08 17:55 ` David Ahern
2023-12-08 17:55 ` David Ahern
2023-12-08 19:23 ` Mina Almasry
2023-12-08 19:23 ` Mina Almasry
2023-12-08 0:52 ` [net-next v1 14/16] net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-12 19:08 ` Simon Horman
2023-12-12 19:08 ` Simon Horman
2023-12-08 0:52 ` [net-next v1 15/16] net: add devmem TCP documentation Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-12 19:14 ` Simon Horman
2023-12-12 19:14 ` Simon Horman
2023-12-08 0:52 ` [net-next v1 16/16] selftests: add ncdevmem, netcat for devmem TCP Mina Almasry
2023-12-08 0:52 ` Mina Almasry
2023-12-08 1:47 ` [net-next v1 00/16] Device Memory TCP Mina Almasry
2023-12-08 1:47 ` Mina Almasry
2023-12-08 17:57 ` David Ahern
2023-12-08 17:57 ` David Ahern
2023-12-08 19:31 ` Mina Almasry
2023-12-08 19:31 ` Mina Almasry
2023-12-10 3:48 ` Shakeel Butt
2023-12-10 3:48 ` Shakeel Butt
2023-12-12 5:58 ` Christoph Hellwig
2023-12-14 6:20 ` patchwork-bot+netdevbpf
2023-12-14 6:20 ` patchwork-bot+netdevbpf
2023-12-14 6:48 ` Christoph Hellwig
2023-12-14 6:51 ` Mina Almasry
2023-12-14 6:51 ` Mina Almasry
2023-12-14 6:59 ` Christoph Hellwig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAHS8izMVMx0fpT=dWsnD7piqs1g7Fam8Xf5dK3iOFNxeOQD9vQ@mail.gmail.com' \
--to=almasrymina@google.com \
--cc=arnd@arndb.de \
--cc=bpf@vger.kernel.org \
--cc=christian.koenig@amd.com \
--cc=corbet@lwn.net \
--cc=davem@davemloft.net \
--cc=dri-devel@lists.freedesktop.org \
--cc=dsahern@kernel.org \
--cc=edumazet@google.com \
--cc=hawk@kernel.org \
--cc=hch@infradead.org \
--cc=hramamurthy@google.com \
--cc=ilias.apalodimas@linaro.org \
--cc=jeroendb@google.com \
--cc=jgg@nvidia.com \
--cc=kaiyuanz@google.com \
--cc=kuba@kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=linyunsheng@huawei.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=pkaligineedi@google.com \
--cc=shailend@google.com \
--cc=shakeelb@google.com \
--cc=shuah@kernel.org \
--cc=sumit.semwal@linaro.org \
--cc=willemb@google.com \
--cc=willemdebruijn.kernel@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.