From: Jakub Kicinski <kuba@kernel.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Luigi Rizzo <lrizzo@google.com>,
"David Hildenbrand (Arm)" <david@kernel.org>,
Luigi Rizzo <rizzo.unipi@gmail.com>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
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>,
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: Fri, 23 Oct 2026 10:27:56 -0700 [thread overview]
Message-ID: <20261023102756.201315d7@kernel.org> (raw)
In-Reply-To: <20261023145023.GH3977851@ziepe.ca>
On Fri, 23 Oct 2026 11:50:23 -0300 Jason Gunthorpe wrote:
> > Anyways, reading your next comments, are you suggesting that all
> > these functionalities should be implemented as pagepool extensions?
> > (2MB mappings and iommu backing, proper allocator of fragments out of larger
> > pages, device-less pagepools, multi-domain mappings, pagepool
> > as memory provider for skb heads, pagepool as memory provider for descriptor
> > rings ?)
>
> netdev shouldn't be touching iommu, it can get a 2M page and map it
> using the normal DMA API. AFAIK there is not such a big reason to need
> any of these layering violations. They just make it easier on page
> pool..
FWIW we're entirely happy on the netdev side to add this to page pool.
In fact the initial RFC I posted for "page pool memory providers"
was addressing this exact use case. I didn't push it forward due
to low time and suspicion that IOMMU folks would prefer a more generic
solution. Since then memory providers were pushed forward and merged
for dmabuf, and we have netlink APIs to configure things. So adding
large mappings should be SMOC.
next prev parent reply other threads:[~2026-10-23 17:27 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-03 21:22 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)
2026-10-14 11:05 ` Luigi Rizzo
2026-10-17 17:11 ` Luigi Rizzo
2026-10-22 20:12 ` Jason Gunthorpe
2026-10-22 21:51 ` Luigi Rizzo
2026-10-23 14:01 ` Jason Gunthorpe
2026-10-23 14:30 ` Luigi Rizzo
2026-10-23 14:50 ` Jason Gunthorpe
2026-10-23 15:12 ` Luigi Rizzo
2026-10-23 17:27 ` Jakub Kicinski [this message]
2026-10-23 20:22 ` 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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