From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Robin Murphy <robin.murphy@arm.com>, Luigi Rizzo <lrizzo@google.com>
Cc: Luigi Rizzo <rizzo.unipi@gmail.com>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@kernel.org>,
"David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@kernel.org>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Danilo Krummrich <dakr@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Willem de Bruijn <willemb@google.com>,
Kuniyuki Iwashima <kuniyu@google.com>,
Joshua Washington <joshwash@google.com>,
Harshitha Ramamurthy <hramamurthy@google.com>,
Saeed Mahameed <saeedm@nvidia.com>,
Tariq Toukan <tariqt@nvidia.com>,
Tony Nguyen <anthony.l.nguyen@intel.com>,
Przemek Kitszel <przemyslaw.kitszel@intel.com>,
Alexander Lobakin <aleksander.lobakin@intel.com>,
Michael Chan <michael.chan@broadcom.com>,
Pavan Chebbi <pavan.chebbi@broadcom.com>,
iommu@lists.linux.dev, netdev@vger.kernel.org,
linux-mm@kvack.org, driver-core@lists.linux.dev,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC: DMA_PMD 00/22] DMA_PMD: PMD_SIZE-backed IO buffer pools
Date: Wed, 14 Oct 2026 12:47:45 +0200 [thread overview]
Message-ID: <75c229ef-ae41-4072-9c90-98d4779c52bf@kernel.org> (raw)
In-Reply-To: <4fda41ed-741b-4c5f-ae83-e3ea5a447441@arm.com>
On 10/13/26 12:42, Robin Murphy wrote:
> On 12/10/2026 8:43 pm, David Hildenbrand (Arm) wrote:
>> On 10/12/26 16:45, Luigi Rizzo wrote:
>>> On Mon, Oct 12, 2026 at 3:51 PM David Hildenbrand (Arm)
>>> <david@kernel.org> wrote:
>>>
>>> I had to call it something... an earlier prototype used the name IOMMU_2M,
>>> but I didn't want to suggest that the design was limited to 2M (it is not).
>>>
>>> Aside from the name, the _current_ prototype restricts to 2M allocations,
>>> exactly because too large units are expensive and wasteful.
>>>
>>> In the code, decoupling the allocation size from the PMD size is trivial.
>>
>> Yeah, we should do that.
>>
>> We should probably just find a way to describe that this is a POOL that focuses
>> on physical contiguity in some configured granularity.
> And since it's intended for DMA we could call it dma_pool and oh look it already
> exists...
Heh, I did have "DMA_POOL" in mind when writing my reply.
>
> Sure the current implementation is capped at PAGE_SIZE for allocation (and thus
> mapping too), but I don't see why that couldn't just be made more flexible.
That intuitively sounds like the right direction.
--
Cheers,
David
next prev parent reply other threads:[~2026-10-14 10:47 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-03 21:22 [RFC: DMA_PMD 00/22] DMA_PMD: PMD_SIZE-backed IO buffer pools Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 01/22] iommu/dma: introduce CONFIG_DMA_PMD and metadata table Luigi Rizzo
2026-10-03 21:44 ` Randy Dunlap
2026-10-04 9:14 ` Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 02/22] iommu/dma: add DMA_PMD pool lifecycle and page recycle hook Luigi Rizzo
2026-10-10 2:59 ` kernel test robot
2026-10-03 21:22 ` [RFC: DMA_PMD 03/22] mm: Add split_page_compound() Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 04/22] iommu/dma: add DMA_PMD pool block allocation Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 05/22] iommu/dma: Global cap and shrinker for DMA_PMD pool memory Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 06/22] iommu/dma: reserve a per-domain IOVA window for DMA_PMD pages Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 07/22] iommu/dma: release DMA_PMD domain mappings on domain teardown Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 08/22] iommu/dma: use per-domain IOVA window to map DMA_PMD memory Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 09/22] iommu/dma: Add DMA_PMD arena allocator Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 10/22] driver core: Add per-device dma_pmd_* sysfs attributes Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 11/22] dma-mapping: Use DMA_PMD arena for dma_alloc_attrs() Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 12/22] net/core: Use per-CPU DMA_PMD pools for skb_page_frag_refill() Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 13/22] net/core: Use DMA_PMD for page_pool memory Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 14/22] iommu/dma: Support decrypted and pinned DMA_PMD pages Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 15/22] iommu/dma: Add background page scrubber for DMA_PMD pools Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 16/22] iommu/dma: Add per-NUMA-node PMD page reservoir Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 17/22] net/gve: Use DMA_PMD memory for RX buffers Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 18/22] net/gve: Use DMA_PMD memory for tx header bounce buffers Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 19/22] net/mlx5e: " Luigi Rizzo
2026-10-14 17:22 ` Dragos Tatulea
2026-10-14 17:50 ` Dragos Tatulea
2026-10-14 18:28 ` Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 20/22] net/idpf: " Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 21/22] net/bnxt: " Luigi Rizzo
2026-10-03 21:22 ` [RFC: DMA_PMD 22/22] iommu/dma: Add DMA_PMD statistics and debugfs Luigi Rizzo
2026-10-11 9:02 ` [RFC: DMA_PMD 00/22] DMA_PMD: PMD_SIZE-backed IO buffer pools Pranjal Shrivastava
2026-10-12 13:51 ` David Hildenbrand (Arm)
2026-10-12 14:45 ` Luigi Rizzo
2026-10-12 19:43 ` David Hildenbrand (Arm)
2026-10-13 10:42 ` Robin Murphy
2026-10-14 10:47 ` David Hildenbrand (Arm) [this message]
2026-10-14 11:05 ` Luigi Rizzo
2026-10-12 14:49 ` Mostafa Saleh
2026-10-12 15:02 ` Luigi Rizzo
2026-10-14 17:28 ` Dragos Tatulea
2026-10-14 18:14 ` Luigi Rizzo
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