From: Logan Gunthorpe <logang@deltatee.com>
To: Bjorn Helgaas <helgaas@kernel.org>, Stephen Bates <sbates@raithlin.com>
Cc: "Sinan Kaya" <okaya@codeaurora.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"Christoph Hellwig" <hch@lst.de>, "Jens Axboe" <axboe@kernel.dk>,
"Keith Busch" <keith.busch@intel.com>,
"Sagi Grimberg" <sagi@grimberg.me>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Jason Gunthorpe" <jgg@mellanox.com>,
"Max Gurtovoy" <maxg@mellanox.com>,
"Dan Williams" <dan.j.williams@intel.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
"Alex Williamson" <alex.williamson@redhat.com>
Subject: Re: [PATCH v3 01/11] PCI/P2PDMA: Support peer-to-peer memory
Date: Fri, 23 Mar 2018 15:59:14 -0600 [thread overview]
Message-ID: <dc414fa5-1af9-0ba7-e12e-4cd9df313119@deltatee.com> (raw)
In-Reply-To: <20180323215046.GC210003@bhelgaas-glaptop.roam.corp.google.com>
On 23/03/18 03:50 PM, Bjorn Helgaas wrote:
> Popping way up the stack, my original point was that I'm trying to
> remove restrictions on what devices can participate in peer-to-peer
> DMA. I think it's fairly clear that in conventional PCI, any devices
> in the same PCI hierarchy, i.e., below the same host-to-PCI bridge,
> should be able to DMA to each other.
Yup, we are working on this.
> The routing behavior of PCIe is supposed to be compatible with
> conventional PCI, and I would argue that this effectively requires
> multi-function PCIe devices to have the internal routing required to
> avoid the route-to-self issue.
That would be very nice but many devices do not support the internal
route. We've had to work around this in the past and as I mentioned
earlier that NVMe devices have a flag indicating support. However, if a
device wants to be involved in P2P it must support it and we can exclude
devices that don't support it by simply not enabling their drivers.
Logan
next prev parent reply other threads:[~2018-03-23 21:59 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-12 19:35 [PATCH v3 00/11] Copy Offload in NVMe Fabrics with P2P PCI Memory Logan Gunthorpe
2018-03-12 19:35 ` [PATCH v3 01/11] PCI/P2PDMA: Support peer-to-peer memory Logan Gunthorpe
2018-03-13 3:28 ` Sinan Kaya
2018-03-13 16:43 ` Logan Gunthorpe
2018-03-13 17:49 ` Sinan Kaya
2018-03-13 18:44 ` Logan Gunthorpe
2018-03-13 19:10 ` Sinan Kaya
2018-03-13 19:19 ` Logan Gunthorpe
2018-03-13 19:53 ` Sinan Kaya
2018-03-13 20:46 ` Logan Gunthorpe
2018-03-13 21:22 ` Sinan Kaya
2018-03-13 22:00 ` Logan Gunthorpe
2018-03-13 22:29 ` Sinan Kaya
2018-03-13 22:45 ` Stephen Bates
2018-03-13 22:48 ` Logan Gunthorpe
2018-03-13 23:19 ` Sinan Kaya
2018-03-13 23:45 ` Logan Gunthorpe
2018-03-14 12:16 ` David Laight
2018-03-14 16:23 ` Logan Gunthorpe
2018-03-13 22:31 ` Stephen Bates
2018-03-13 23:08 ` Bjorn Helgaas
2018-03-13 23:21 ` Logan Gunthorpe
2018-03-14 2:56 ` Bjorn Helgaas
2018-03-14 14:05 ` Stephen Bates
2018-03-14 16:17 ` Logan Gunthorpe
2018-03-14 18:51 ` Bjorn Helgaas
2018-03-14 19:03 ` Logan Gunthorpe
2018-03-14 19:28 ` Dan Williams
2018-03-14 19:30 ` Logan Gunthorpe
2018-03-14 19:34 ` Stephen Bates
2018-03-15 4:00 ` Martin K. Petersen
2018-03-15 4:30 ` Dan Williams
2018-03-22 22:57 ` Stephen Bates
2018-03-23 21:50 ` Bjorn Helgaas
2018-03-23 21:59 ` Logan Gunthorpe [this message]
2018-03-24 3:49 ` Bjorn Helgaas
2018-03-24 15:28 ` Stephen Bates
2018-03-26 15:43 ` Logan Gunthorpe
2018-03-26 11:11 ` Jonathan Cameron
2018-03-26 14:01 ` Bjorn Helgaas
2018-03-26 15:46 ` Logan Gunthorpe
2018-03-27 8:47 ` Jonathan Cameron
2018-03-27 15:37 ` Logan Gunthorpe
2018-04-13 21:56 ` Stephen Bates
2018-03-26 16:41 ` Jason Gunthorpe
2018-03-26 17:30 ` Logan Gunthorpe
2018-03-26 19:35 ` Jason Gunthorpe
2018-03-26 20:42 ` Logan Gunthorpe
2018-03-13 18:40 ` Logan Gunthorpe
2018-03-12 19:35 ` [PATCH v3 02/11] PCI/P2PDMA: Add sysfs group to display p2pmem stats Logan Gunthorpe
2018-03-12 19:35 ` [PATCH v3 03/11] PCI/P2PDMA: Add PCI p2pmem dma mappings to adjust the bus offset Logan Gunthorpe
2018-03-12 19:35 ` [PATCH v3 04/11] PCI/P2PDMA: Clear ACS P2P flags for all devices behind switches Logan Gunthorpe
2018-03-12 19:35 ` [PATCH v3 05/11] PCI/P2PDMA: Add P2P DMA driver writer's documentation Logan Gunthorpe
2018-03-12 19:41 ` Jonathan Corbet
2018-03-12 21:18 ` Logan Gunthorpe
2018-03-12 19:35 ` [PATCH v3 06/11] block: Introduce PCI P2P flags for request and request queue Logan Gunthorpe
2018-03-21 9:27 ` Christoph Hellwig
2018-03-12 19:35 ` [PATCH v3 07/11] IB/core: Ensure we map P2P memory correctly in rdma_rw_ctx_[init|destroy]() Logan Gunthorpe
2018-03-21 9:27 ` Christoph Hellwig
2018-03-12 19:35 ` [PATCH v3 08/11] nvme-pci: Use PCI p2pmem subsystem to manage the CMB Logan Gunthorpe
2018-03-13 1:55 ` Sinan Kaya
2018-03-13 1:58 ` Sinan Kaya
2018-03-12 19:35 ` [PATCH v3 09/11] nvme-pci: Add support for P2P memory in requests Logan Gunthorpe
2018-03-21 9:23 ` Christoph Hellwig
2018-03-12 19:35 ` [PATCH v3 10/11] nvme-pci: Add a quirk for a pseudo CMB Logan Gunthorpe
2018-03-12 19:35 ` [PATCH v3 11/11] nvmet: Optionally use PCI P2P memory Logan Gunthorpe
2018-03-21 9:27 ` Christoph Hellwig
2018-03-21 16:52 ` Logan Gunthorpe
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