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From: Jason Gunthorpe <jgg@mellanox.com>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: Jerome Glisse <jglisse@redhat.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Christian Koenig <christian.koenig@amd.com>,
	Felix Kuehling <Felix.Kuehling@amd.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>, Christoph Hellwig <hch@lst.de>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <jroedel@suse.de>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>
Subject: Re: [RFC PATCH 3/5] mm/vma: add support for peer to peer to device vma
Date: Tue, 29 Jan 2019 20:58:35 +0000	[thread overview]
Message-ID: <20190129205827.GM10108@mellanox.com> (raw)
In-Reply-To: <99c228c6-ef96-7594-cb43-78931966c75d@deltatee.com>

On Tue, Jan 29, 2019 at 01:39:49PM -0700, Logan Gunthorpe wrote:

> implement the mapping. And I don't think we should have 'special' vma's
> for this (though we may need something to ensure we don't get mapping
> requests mixed with different types of pages...).

I think Jerome explained the point here is to have a 'special vma'
rather than a 'special struct page' as, really, we don't need a
struct page at all to make this work.

If I recall your earlier attempts at adding struct page for BAR
memory, it ran aground on issues related to O_DIRECT/sgls, etc, etc.

This does seem to avoid that pitfall entirely as we can never
accidently get into the SGL system with this kind of memory or VMA?

Jason

  parent reply	other threads:[~2019-01-29 20:58 UTC|newest]

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-29 17:47 [RFC PATCH 0/5] Device peer to peer (p2p) through vma jglisse
2019-01-29 17:47 ` [RFC PATCH 1/5] pci/p2p: add a function to test peer to peer capability jglisse
2019-01-29 18:24   ` Logan Gunthorpe
2019-01-29 19:44     ` Greg Kroah-Hartman
2019-01-29 19:53       ` Jerome Glisse
2019-01-29 20:44       ` Logan Gunthorpe
2019-01-29 21:00         ` Jerome Glisse
2019-01-29 19:56   ` Alex Deucher
2019-01-29 20:00     ` Jerome Glisse
2019-01-29 20:24     ` Logan Gunthorpe
2019-01-29 21:28       ` Alex Deucher
2019-01-30 10:25       ` Christian König
2019-01-29 17:47 ` [RFC PATCH 2/5] drivers/base: " jglisse
2019-01-29 18:26   ` Logan Gunthorpe
2019-01-29 19:54     ` Jerome Glisse
2019-01-29 19:46   ` Greg Kroah-Hartman
2019-01-29 19:56     ` Jerome Glisse
2019-01-29 17:47 ` [RFC PATCH 3/5] mm/vma: add support for peer to peer to device vma jglisse
2019-01-29 18:36   ` Logan Gunthorpe
2019-01-29 19:11     ` Jerome Glisse
2019-01-29 19:24       ` Logan Gunthorpe
2019-01-29 19:44         ` Jerome Glisse
2019-01-29 20:43           ` Logan Gunthorpe
2019-01-30  7:52             ` Christoph Hellwig
2019-01-29 19:32       ` Jason Gunthorpe
2019-01-29 19:50         ` Jerome Glisse
2019-01-29 20:24           ` Jason Gunthorpe
2019-01-29 20:44             ` Jerome Glisse
2019-01-29 23:02               ` Jason Gunthorpe
2019-01-30  0:08                 ` Jerome Glisse
2019-01-30  4:30                   ` Jason Gunthorpe
2019-01-30 15:43                     ` Jerome Glisse
2019-01-29 20:39         ` Logan Gunthorpe
2019-01-29 20:57           ` Jerome Glisse
2019-01-29 21:30             ` Logan Gunthorpe
2019-01-29 21:50               ` Jerome Glisse
2019-01-29 22:58                 ` Logan Gunthorpe
2019-01-29 23:47                   ` Jerome Glisse
2019-01-30  1:17                     ` Logan Gunthorpe
2019-01-30  2:48                       ` Jerome Glisse
2019-01-30  4:18                       ` Jason Gunthorpe
2019-01-30  8:00                         ` Christoph Hellwig
2019-01-30 15:49                           ` Jerome Glisse
2019-01-30 19:06                           ` Jason Gunthorpe
2019-01-30 19:45                             ` Logan Gunthorpe
2019-01-30 19:59                               ` Jason Gunthorpe
2019-01-30 21:01                                 ` Logan Gunthorpe
2019-01-30 21:50                                   ` Jason Gunthorpe
2019-01-30 22:52                                     ` Logan Gunthorpe
2019-01-30 23:30                                       ` Jason Gunthorpe
2019-01-31  8:13                                       ` Christoph Hellwig
2019-01-31 15:37                                         ` Jerome Glisse
2019-01-31 19:02                                         ` Jason Gunthorpe
2019-01-31 19:19                                           ` Logan Gunthorpe
2019-01-31 19:54                                             ` Jason Gunthorpe
2019-01-31 19:35                                           ` Jerome Glisse
2019-01-31 19:44                                             ` Logan Gunthorpe
2019-01-31 19:58                                             ` Jason Gunthorpe
2019-01-30 17:17                         ` Logan Gunthorpe
2019-01-30 18:56                           ` Jason Gunthorpe
2019-01-30 19:22                             ` Jerome Glisse
2019-01-30 19:38                               ` Jason Gunthorpe
2019-01-30 20:00                                 ` Logan Gunthorpe
2019-01-30 20:11                                   ` Jason Gunthorpe
2019-01-30 20:43                                     ` Jerome Glisse
2019-01-30 20:50                                       ` Jason Gunthorpe
2019-01-30 21:45                                         ` Jerome Glisse
2019-01-30 21:56                                           ` Jason Gunthorpe
2019-01-30 22:30                                             ` Jerome Glisse
2019-01-30 22:33                                               ` Jason Gunthorpe
2019-01-30 22:47                                                 ` Jerome Glisse
2019-01-30 22:51                                                   ` Jason Gunthorpe
2019-01-30 22:58                                                     ` Jerome Glisse
2019-01-30 19:52                               ` Logan Gunthorpe
2019-01-30 20:35                                 ` Jerome Glisse
2019-01-29 20:58           ` Jason Gunthorpe [this message]
2019-01-30  8:02             ` Christoph Hellwig
2019-01-30 10:33               ` Koenig, Christian
2019-01-30 15:55                 ` Jerome Glisse
2019-01-30 17:26                   ` Christoph Hellwig
2019-01-30 17:32                     ` Logan Gunthorpe
2019-01-30 17:39                     ` Jason Gunthorpe
2019-01-30 18:05                     ` Jerome Glisse
2019-01-30 17:44               ` Jason Gunthorpe
2019-01-30 18:13                 ` Logan Gunthorpe
2019-01-30 18:50                   ` Jerome Glisse
2019-01-31  8:02                     ` Christoph Hellwig
2019-01-31 15:03                       ` Jerome Glisse
2019-01-30 19:19                   ` Jason Gunthorpe
2019-01-30 19:48                     ` Logan Gunthorpe
2019-01-30 20:44                       ` Jason Gunthorpe
2019-01-31  8:05                         ` Christoph Hellwig
2019-01-31 15:11                           ` Jerome Glisse
2019-01-29 17:47 ` [RFC PATCH 4/5] mm/hmm: add support for peer to peer to HMM device memory jglisse
2019-01-29 17:47 ` [RFC PATCH 5/5] mm/hmm: add support for peer to peer to special device vma jglisse

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