From: Jason Gunthorpe <jgg@ziepe.ca>
To: Mina Almasry <almasrymina@google.com>
Cc: netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
Pavel Begunkov <asml.silence@gmail.com>,
Willem de Bruijn <willemb@google.com>,
Kaiyuan Zhang <kaiyuanz@google.com>,
Samiullah Khawaja <skhawaja@google.com>,
linux-kernel@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>
Subject: Re: [PATCH net-next v2 4/5] page_pool: disable sync for cpu for dmabuf memory provider
Date: Fri, 8 Nov 2024 10:18:12 -0400 [thread overview]
Message-ID: <20241108141812.GL35848@ziepe.ca> (raw)
In-Reply-To: <20241107212309.3097362-5-almasrymina@google.com>
On Thu, Nov 07, 2024 at 09:23:08PM +0000, Mina Almasry wrote:
> dmabuf dma-addresses should not be dma_sync'd for CPU/device. Typically
> its the driver responsibility to dma_sync for CPU, but the driver should
> not dma_sync for CPU if the netmem is actually coming from a dmabuf
> memory provider.
This is not completely true, it is not *all* dmabuf, just the parts of
the dmabuf that are actually MMIO.
If you do this you may want to block accepting dmabufs that have CPU
pages inside them.
Jason
next prev parent reply other threads:[~2024-11-08 14:18 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-07 21:23 [PATCH net-next v2 0/5] devmem TCP fixes Mina Almasry
2024-11-07 21:23 ` [PATCH net-next v2 1/5] net: page_pool: rename page_pool_alloc_netmem to *_netmems Mina Almasry
2024-11-08 15:53 ` Stanislav Fomichev
2024-11-07 21:23 ` [PATCH net-next v2 2/5] net: page_pool: create page_pool_alloc_netmem Mina Almasry
2024-11-08 15:53 ` Stanislav Fomichev
2024-11-07 21:23 ` [PATCH net-next v2 3/5] page_pool: Set `dma_sync` to false for devmem memory provider Mina Almasry
2024-11-08 15:53 ` Stanislav Fomichev
2024-11-08 16:34 ` Pavel Begunkov
2024-11-12 2:34 ` Jakub Kicinski
2024-11-07 21:23 ` [PATCH net-next v2 4/5] page_pool: disable sync for cpu for dmabuf " Mina Almasry
2024-11-08 14:18 ` Jason Gunthorpe [this message]
2024-11-08 15:58 ` Stanislav Fomichev
2024-11-08 16:39 ` Pavel Begunkov
2024-11-08 19:01 ` Mina Almasry
2024-11-15 1:59 ` Jason Gunthorpe
2024-11-22 22:10 ` Samiullah Khawaja
2024-11-24 2:33 ` Jakub Kicinski
2024-11-07 21:23 ` [PATCH net-next v2 5/5] netmem: add netmem_prefetch Mina Almasry
2024-11-08 2:56 ` kernel test robot
2024-11-08 3:29 ` kernel test robot
2024-11-08 4:21 ` kernel test robot
2024-11-08 15:55 ` Stanislav Fomichev
2024-11-12 2:35 ` Jakub Kicinski
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