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From: Logan Gunthorpe <logang@deltatee.com>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
	Bjorn Helgaas <helgaas@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Jens Axboe <axboe@kernel.dk>,
	Steve Wise <swise@opengridcomputing.com>,
	Stephen Bates <sbates@raithlin.com>,
	Max Gurtovoy <maxg@mellanox.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Keith Busch <keith.busch@intel.com>,
	linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org,
	linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
	linux-nvdimm@ml01.01.org, linux-kernel@vger.kernel.org,
	Jerome Glisse <jglisse@redhat.com>
Subject: Re: [RFC 0/8] Copy Offload with Peer-to-Peer PCI Memory
Date: Thu, 13 Apr 2017 22:40:46 -0600	[thread overview]
Message-ID: <08c32f0d-6c7c-b65f-6453-dde0d7c173d1@deltatee.com> (raw)
In-Reply-To: <20170414041656.GA30694@obsidianresearch.com>



On 13/04/17 10:16 PM, Jason Gunthorpe wrote:
> I'd suggest just detecting if there is any translation in bus
> addresses anywhere and just hard disabling P2P on such systems.

That's a fantastic suggestion. It simplifies things significantly.
Unless there are any significant objections I think I will plan on doing
that.

> On modern hardware with 64 bit BARs there is very little reason to
> have translation, so I think this is a legacy feature.

Yes, p2pmem users are likely to be designing systems around it (ie
JBOFs) and not trying to shoehorn it onto legacy architectures.

At the very least, it makes sense to leave it out and if someone comes
along who cares they can put in the effort to support the address
translation.

Thanks,

Logan

  reply	other threads:[~2017-04-14  4:41 UTC|newest]

Thread overview: 155+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-30 22:12 [RFC 0/8] Copy Offload with Peer-to-Peer PCI Memory Logan Gunthorpe
2017-03-30 22:12 ` [RFC 1/8] Introduce Peer-to-Peer memory (p2pmem) device Logan Gunthorpe
2017-03-31 18:49   ` Sinan Kaya
2017-03-31 21:23     ` Logan Gunthorpe
2017-03-31 21:38       ` Sinan Kaya
2017-03-31 22:42         ` Logan Gunthorpe
2017-03-31 23:51           ` Sinan Kaya
2017-04-01  1:57             ` Logan Gunthorpe
2017-04-01  2:17               ` okaya
2017-04-01 22:16                 ` Logan Gunthorpe
2017-04-02  2:26                   ` Sinan Kaya
2017-04-02 17:21                     ` Logan Gunthorpe
2017-04-02 21:03                       ` Sinan Kaya
2017-04-03  4:26                         ` Logan Gunthorpe
2017-04-25 11:58                           ` Marta Rybczynska
2017-04-25 16:58                             ` Logan Gunthorpe
2017-03-30 22:12 ` [RFC 2/8] cxgb4: setup pcie memory window 4 and create p2pmem region Logan Gunthorpe
2017-04-04 10:42   ` Sagi Grimberg
2017-04-04 15:56     ` Logan Gunthorpe
2017-04-05 15:41     ` Steve Wise
2017-03-30 22:12 ` [RFC 3/8] nvmet: Use p2pmem in nvme target Logan Gunthorpe
2017-04-04 10:40   ` Sagi Grimberg
2017-04-04 16:16     ` Logan Gunthorpe
2017-04-06  5:47       ` Sagi Grimberg
2017-04-06 15:52         ` Logan Gunthorpe
2017-03-30 22:12 ` [RFC 4/8] p2pmem: Add debugfs "stats" file Logan Gunthorpe
2017-04-04 10:46   ` Sagi Grimberg
2017-04-04 17:25     ` Logan Gunthorpe
2017-04-05 15:43     ` Steve Wise
2017-03-30 22:12 ` [RFC 5/8] scatterlist: Modify SG copy functions to support io memory Logan Gunthorpe
2017-03-31  7:09   ` Christoph Hellwig
2017-03-31 15:41     ` Logan Gunthorpe
2017-04-03 21:20       ` Logan Gunthorpe
2017-04-03 21:44         ` Dan Williams
2017-04-03 22:10           ` Logan Gunthorpe
2017-04-03 22:47             ` Dan Williams
2017-04-03 23:12               ` Logan Gunthorpe
2017-04-04  0:07                 ` Dan Williams
2017-04-07 17:59                   ` Logan Gunthorpe
2017-03-30 22:12 ` [RFC 6/8] nvmet: Be careful about using iomem accesses when dealing with p2pmem Logan Gunthorpe
2017-04-04 10:59   ` Sagi Grimberg
2017-04-04 15:46     ` Jason Gunthorpe
2017-04-04 17:21       ` Logan Gunthorpe
2017-04-06  5:33       ` Sagi Grimberg
2017-04-06 16:02         ` Logan Gunthorpe
2017-04-06 16:35         ` Jason Gunthorpe
2017-04-07 11:19         ` Stephen  Bates
2017-04-10  8:29           ` Sagi Grimberg
2017-04-10 16:03             ` Logan Gunthorpe
2017-03-30 22:12 ` [RFC 7/8] p2pmem: Support device removal Logan Gunthorpe
2017-03-30 22:12 ` [RFC 8/8] p2pmem: Added char device user interface Logan Gunthorpe
2017-04-12  5:22 ` [RFC 0/8] Copy Offload with Peer-to-Peer PCI Memory Benjamin Herrenschmidt
2017-04-12 17:09   ` Logan Gunthorpe
2017-04-12 21:55     ` Benjamin Herrenschmidt
2017-04-13 21:22       ` Logan Gunthorpe
2017-04-13 22:37         ` Benjamin Herrenschmidt
2017-04-13 23:26         ` Bjorn Helgaas
2017-04-14  4:16           ` Jason Gunthorpe
2017-04-14  4:40             ` Logan Gunthorpe [this message]
2017-04-14 11:37               ` Benjamin Herrenschmidt
2017-04-14 11:39                 ` Benjamin Herrenschmidt
2017-04-14 11:37             ` Benjamin Herrenschmidt
2017-04-14 17:30               ` Logan Gunthorpe
2017-04-14 19:04                 ` Bjorn Helgaas
2017-04-14 22:07                   ` Benjamin Herrenschmidt
2017-04-15 17:41                     ` Logan Gunthorpe
2017-04-15 22:09                       ` Dan Williams
2017-04-16  3:01                         ` Benjamin Herrenschmidt
2017-04-16  4:46                           ` Logan Gunthorpe
2017-04-16 15:53                           ` Dan Williams
2017-04-16 16:34                             ` Logan Gunthorpe
2017-04-16 22:31                               ` Benjamin Herrenschmidt
2017-04-24  7:36                                 ` Knut Omang
2017-04-24 16:14                                   ` Logan Gunthorpe
2017-04-25  6:30                                     ` Knut Omang
2017-04-25 17:03                                       ` Logan Gunthorpe
2017-04-25 21:23                                         ` Stephen  Bates
2017-04-25 21:23                                   ` Stephen  Bates
2017-04-16 22:26                             ` Benjamin Herrenschmidt
2017-04-15 22:17                       ` Benjamin Herrenschmidt
2017-04-16  5:36                         ` Logan Gunthorpe
2017-04-16 15:44 Dan Williams
2017-04-16 16:47 ` Logan Gunthorpe
2017-04-16 22:32   ` Benjamin Herrenschmidt
2017-04-17  5:13     ` Logan Gunthorpe
2017-04-17  7:20       ` Benjamin Herrenschmidt
2017-04-17 16:52         ` Logan Gunthorpe
2017-04-17 17:04           ` Dan Williams
2017-04-18  5:22             ` Logan Gunthorpe
2017-04-17 18:04           ` Jerome Glisse
2017-04-18  6:14             ` Logan Gunthorpe
2017-04-17 21:11           ` Benjamin Herrenschmidt
2017-04-18  5:43             ` Logan Gunthorpe
2017-04-18  6:29               ` Benjamin Herrenschmidt
2017-04-16 22:23 ` Benjamin Herrenschmidt
2017-04-18 16:45   ` Jason Gunthorpe
2017-04-18 17:27     ` Dan Williams
2017-04-18 18:00       ` Jason Gunthorpe
2017-04-18 18:34         ` Dan Williams
2017-04-19  1:13         ` Benjamin Herrenschmidt
2017-04-18 22:46       ` Benjamin Herrenschmidt
2017-04-18 22:52         ` Dan Williams
2017-04-18 18:30     ` Logan Gunthorpe
2017-04-18 19:01       ` Jason Gunthorpe
2017-04-18 19:35         ` Logan Gunthorpe
2017-04-18 19:48           ` Dan Williams
2017-04-18 20:29             ` Jerome Glisse
2017-04-18 20:31               ` Dan Williams
2017-04-18 20:48                 ` Logan Gunthorpe
2017-04-19  1:17                   ` Benjamin Herrenschmidt
2017-04-18 21:03             ` Jason Gunthorpe
2017-04-18 21:11               ` Dan Williams
2017-04-18 21:22                 ` Jason Gunthorpe
2017-04-18 21:36                   ` Dan Williams
2017-04-18 22:15                     ` Logan Gunthorpe
2017-04-18 22:28                       ` Dan Williams
2017-04-18 22:42                         ` Jason Gunthorpe
2017-04-18 22:51                           ` Dan Williams
2017-04-18 23:21                             ` Jason Gunthorpe
2017-04-19  1:25                               ` Benjamin Herrenschmidt
2017-04-18 22:48                         ` Logan Gunthorpe
2017-04-18 22:50                           ` Dan Williams
2017-04-18 22:56                             ` Logan Gunthorpe
2017-04-18 23:02                               ` Dan Williams
2017-04-19  1:21                   ` Benjamin Herrenschmidt
2017-04-18 21:31               ` Logan Gunthorpe
2017-04-18 22:24                 ` Jason Gunthorpe
2017-04-18 23:03                   ` Logan Gunthorpe
2017-04-19  1:23                   ` Benjamin Herrenschmidt
2017-04-19  1:20               ` Benjamin Herrenschmidt
2017-04-19 15:55                 ` Jason Gunthorpe
2017-04-19 16:48                   ` Logan Gunthorpe
2017-04-19 17:01                     ` Dan Williams
2017-04-19 17:32                       ` Jerome Glisse
2017-04-19 17:41                         ` Dan Williams
2017-04-19 18:11                           ` Logan Gunthorpe
2017-04-19 18:19                             ` Logan Gunthorpe
2017-04-19 18:30                               ` Dan Williams
2017-04-19 18:41                                 ` Logan Gunthorpe
2017-04-19 18:44                                   ` Dan Williams
2017-04-20 20:43                           ` Stephen  Bates
2017-04-20 20:47                             ` Dan Williams
2017-04-20 23:07                               ` Stephen  Bates
2017-04-21  4:59                                 ` Dan Williams
2017-04-19 17:14                     ` Jason Gunthorpe
2017-04-19 18:01                       ` Logan Gunthorpe
2017-04-19 18:32                         ` Jason Gunthorpe
2017-04-19 19:02                           ` Logan Gunthorpe
2017-04-19 19:31                             ` Jason Gunthorpe
2017-04-19 19:41                               ` Logan Gunthorpe
2017-04-19 20:48                                 ` Jason Gunthorpe
2017-04-19 22:55                                   ` Logan Gunthorpe
2017-04-20  0:07                                     ` Dan Williams
2017-04-18 19:48           ` Jason Gunthorpe
2017-04-18 20:06             ` Logan Gunthorpe

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