From: Jakub Kicinski <kuba@kernel.org>
To: Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Mina Almasry <almasrymina@google.com>
Cc: Yunsheng Lin <linyunsheng@huawei.com>,
davem@davemloft.net, pabeni@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
Lorenzo Bianconi <lorenzo@kernel.org>,
Alexander Duyck <alexander.duyck@gmail.com>,
Liang Chen <liangchen.linux@gmail.com>,
Alexander Lobakin <aleksander.lobakin@intel.com>,
Saeed Mahameed <saeedm@nvidia.com>,
Leon Romanovsky <leon@kernel.org>,
Eric Dumazet <edumazet@google.com>,
Jesper Dangaard Brouer <hawk@kernel.org>
Subject: Re: [PATCH net-next v7 1/6] page_pool: frag API support for 32-bit arch with 64-bit DMA
Date: Thu, 17 Aug 2023 09:15:54 -0700 [thread overview]
Message-ID: <20230817091554.31bb3600@kernel.org> (raw)
In-Reply-To: <CAC_iWjJd8Td_uAonvq_89WquX9wpAx0EYYxYMbm3TTxb2+trYg@mail.gmail.com>
On Thu, 17 Aug 2023 16:57:16 +0300 Ilias Apalodimas wrote:
> Why should we care about this? Even an architecture that's 32-bit and
> has a 64bit DMA should be allowed to split the pages internally if it
> decides to do so. The trick that drivers usually do is elevate the
> page refcnt and deal with that internally.
Can we assume the DMA mapping of page pool is page aligned? We should
be, right? That means we're storing 12 bits of 0 at the lower end.
So even with 32b of space we can easily store addresses for 32b+12b =>
16TB of memory. "Ought to be enough" to paraphrase Bill G, and the
problem is only in our heads?
Before we go that way - Mina, are the dma-buf "chunks" you're working
with going to be fragment-able? Or rather can driver and/or core take
multiple references on a single buffer?
next prev parent reply other threads:[~2023-08-17 16:17 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-16 10:01 [PATCH net-next v7 0/6] introduce page_pool_alloc() related API Yunsheng Lin
2023-08-16 10:01 ` [PATCH net-next v7 1/6] page_pool: frag API support for 32-bit arch with 64-bit DMA Yunsheng Lin
2023-08-17 13:57 ` Ilias Apalodimas
2023-08-17 16:15 ` Jakub Kicinski [this message]
2023-08-17 16:59 ` Ilias Apalodimas
2023-08-17 23:57 ` Jakub Kicinski
2023-08-18 6:12 ` Ilias Apalodimas
2023-08-18 8:59 ` Yunsheng Lin
2023-08-18 21:51 ` Jakub Kicinski
2023-08-21 8:38 ` Ilias Apalodimas
2023-08-21 11:15 ` Ilias Apalodimas
2023-08-21 12:18 ` Yunsheng Lin
2023-08-21 18:35 ` Jakub Kicinski
2023-08-22 9:21 ` Yunsheng Lin
2023-08-22 15:38 ` Jakub Kicinski
2023-08-22 18:30 ` Alexander Duyck
2023-08-22 18:58 ` Alexander Duyck
2023-08-23 3:03 ` Yunsheng Lin
2023-08-23 14:25 ` Jakub Kicinski
2023-08-23 18:00 ` Alexander Duyck
2023-08-25 9:40 ` Yunsheng Lin
2023-08-26 0:08 ` Jakub Kicinski
2023-08-28 14:50 ` Alexander Duyck
2023-08-28 15:38 ` Jakub Kicinski
2023-08-29 11:58 ` Yunsheng Lin
2023-08-16 10:01 ` [PATCH net-next v7 2/6] page_pool: unify frag_count handling in page_pool_is_last_frag() Yunsheng Lin
2023-08-16 11:30 ` Ilias Apalodimas
2023-08-16 12:42 ` Yunsheng Lin
2023-08-16 10:01 ` [PATCH net-next v7 3/6] page_pool: remove PP_FLAG_PAGE_FRAG Yunsheng Lin
2023-08-16 10:01 ` [PATCH net-next v7 4/6] page_pool: introduce page_pool[_cache]_alloc() API Yunsheng Lin
2023-08-16 10:01 ` [PATCH net-next v7 5/6] page_pool: update document about frag API Yunsheng Lin
2023-08-16 10:01 ` [PATCH net-next v7 6/6] net: veth: use newly added page pool API for veth with xdp Yunsheng Lin
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