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From: Logan Gunthorpe <logang@deltatee.com>
To: Dan Williams <dan.j.williams@intel.com>, benh@au1.ibm.com
Cc: "Jens Axboe" <axboe@kernel.dk>,
	"Keith Busch" <keith.busch@intel.com>,
	"Oliver OHalloran" <oliveroh@au1.ibm.com>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	linux-nvdimm <linux-nvdimm@lists.01.org>,
	linux-rdma <linux-rdma@vger.kernel.org>,
	linux-pci@vger.kernel.org,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Jason Gunthorpe" <jgg@mellanox.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Max Gurtovoy" <maxg@mellanox.com>,
	"Christoph Hellwig" <hch@lst.de>
Subject: Re: [PATCH v2 00/10] Copy Offload in NVMe Fabrics with P2P PCI Memory
Date: Thu, 1 Mar 2018 14:57:06 -0700	[thread overview]
Message-ID: <43ba615f-a6e1-9444-65e1-494169cb415d@deltatee.com> (raw)
In-Reply-To: <2079ba48-5ae5-5b44-cce1-8175712dd395@deltatee.com>



On 01/03/18 02:45 PM, Logan Gunthorpe wrote:
> It handles it fine for many situations. But when you try to map 
> something that is at the end of the physical address space then the 
> spares-vmemmap needs virtual address space that's the size of the 
> physical address space divided by PAGE_SIZE which may be a little bit 
> too large...

Though, considering this more, maybe this shouldn't be a problem...

Lets say you have 56bits of address space. That's 64PB. If you use need 
a sparse vmemmap for the entire space it will take 16TB which leaves you 
with 63.98PB of address space left. (Similar calculations for other 
numbers of address bits.)

So I'm not sure what the problem with this is.

We still have to ensure all the arches map the memory with the right 
cache bits but that should be relatively easy to solve.

Logan

  reply	other threads:[~2018-03-01 21:57 UTC|newest]

Thread overview: 124+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-28 23:39 [PATCH v2 00/10] Copy Offload in NVMe Fabrics with P2P PCI Memory Logan Gunthorpe
2018-02-28 23:39 ` [PATCH v2 01/10] PCI/P2PDMA: Support peer to peer memory Logan Gunthorpe
2018-03-01 17:37   ` Bjorn Helgaas
2018-03-01 18:55     ` Logan Gunthorpe
2018-03-01 23:00       ` Bjorn Helgaas
2018-03-01 23:06         ` Logan Gunthorpe
2018-03-01 23:14           ` Stephen  Bates
2018-03-01 23:45             ` Bjorn Helgaas
2018-02-28 23:39 ` [PATCH v2 02/10] PCI/P2PDMA: Add sysfs group to display p2pmem stats Logan Gunthorpe
2018-03-01 17:44   ` Bjorn Helgaas
2018-03-02  0:15     ` Logan Gunthorpe
2018-03-02  0:36       ` Dan Williams
2018-03-02  0:37         ` Logan Gunthorpe
2018-02-28 23:39 ` [PATCH v2 03/10] PCI/P2PDMA: Add PCI p2pmem dma mappings to adjust the bus offset Logan Gunthorpe
2018-03-01 17:49   ` Bjorn Helgaas
2018-03-01 19:36     ` Logan Gunthorpe
2018-02-28 23:40 ` [PATCH v2 04/10] PCI/P2PDMA: Clear ACS P2P flags for all devices behind switches Logan Gunthorpe
2018-03-01 18:02   ` Bjorn Helgaas
2018-03-01 18:54     ` Stephen  Bates
2018-03-01 21:21       ` Alex Williamson
2018-03-01 21:26         ` Logan Gunthorpe
2018-03-01 21:32         ` Stephen  Bates
2018-03-01 21:35           ` Jerome Glisse
2018-03-01 21:37             ` Logan Gunthorpe
2018-03-01 23:15       ` Bjorn Helgaas
2018-03-01 23:59         ` Logan Gunthorpe
2018-03-01 19:13     ` Logan Gunthorpe
2018-03-05 22:28       ` Bjorn Helgaas
2018-03-05 23:01         ` Logan Gunthorpe
2018-02-28 23:40 ` [PATCH v2 05/10] block: Introduce PCI P2P flags for request and request queue Logan Gunthorpe
2018-03-01 11:08   ` Sagi Grimberg
2018-02-28 23:40 ` [PATCH v2 06/10] IB/core: Add optional PCI P2P flag to rdma_rw_ctx_[init|destroy]() Logan Gunthorpe
2018-03-01 10:32   ` Sagi Grimberg
2018-03-01 17:16     ` Logan Gunthorpe
2018-02-28 23:40 ` [PATCH v2 07/10] nvme-pci: Use PCI p2pmem subsystem to manage the CMB Logan Gunthorpe
2018-03-05  1:33   ` Oliver
2018-03-05 16:00     ` Keith Busch
2018-03-05 17:10       ` Logan Gunthorpe
2018-03-05 18:02         ` Sinan Kaya
2018-03-05 18:09           ` Logan Gunthorpe
2018-03-06  0:49         ` Oliver
2018-03-06  1:14           ` Logan Gunthorpe
2018-03-06 10:40             ` Oliver
2018-03-05 19:57       ` Sagi Grimberg
2018-03-05 20:10         ` Jason Gunthorpe
2018-03-05 20:16           ` Logan Gunthorpe
2018-03-05 20:42           ` Keith Busch
2018-03-05 20:50             ` Jason Gunthorpe
2018-03-05 20:13         ` Logan Gunthorpe
2018-02-28 23:40 ` [PATCH v2 08/10] nvme-pci: Add support for P2P memory in requests Logan Gunthorpe
2018-03-01 11:07   ` Sagi Grimberg
2018-03-01 15:58     ` Stephen  Bates
2018-03-09  5:08       ` Bart Van Assche
2018-02-28 23:40 ` [PATCH v2 09/10] nvme-pci: Add a quirk for a pseudo CMB Logan Gunthorpe
2018-03-01 11:03   ` Sagi Grimberg
2018-02-28 23:40 ` [PATCH v2 10/10] nvmet: Optionally use PCI P2P memory Logan Gunthorpe
2018-03-01 11:03   ` Sagi Grimberg
2018-03-01 16:15     ` Stephen  Bates
2018-03-01 17:40     ` Logan Gunthorpe
2018-03-01 18:35       ` Sagi Grimberg
2018-03-01 18:42         ` Jason Gunthorpe
2018-03-01 19:01           ` Stephen  Bates
2018-03-01 19:27           ` Logan Gunthorpe
2018-03-01 22:45             ` Jason Gunthorpe
2018-03-01 22:56               ` Logan Gunthorpe
2018-03-01 23:00               ` Stephen  Bates
2018-03-01 23:20                 ` Jason Gunthorpe
2018-03-01 23:29                   ` Logan Gunthorpe
2018-03-01 23:32                   ` Stephen  Bates
2018-03-01 23:49                 ` Keith Busch
2018-03-01 23:52                   ` Logan Gunthorpe
2018-03-01 23:53                   ` Stephen  Bates
2018-03-02 15:53                     ` Christoph Hellwig
2018-03-02 20:51                       ` Stephen  Bates
2018-03-01 23:57                   ` Stephen  Bates
2018-03-02  0:03                     ` Logan Gunthorpe
2018-03-02 16:18                     ` Jason Gunthorpe
2018-03-02 17:10                       ` Logan Gunthorpe
2018-03-01 19:10         ` Logan Gunthorpe
2018-03-01  3:54 ` [PATCH v2 00/10] Copy Offload in NVMe Fabrics with P2P PCI Memory Benjamin Herrenschmidt
2018-03-01  3:56   ` Benjamin Herrenschmidt
2018-03-01 18:04     ` Logan Gunthorpe
2018-03-01 20:29       ` Benjamin Herrenschmidt
2018-03-01 20:55         ` Jerome Glisse
2018-03-01 21:03           ` Logan Gunthorpe
2018-03-01 21:10             ` Jerome Glisse
2018-03-01 21:15               ` Logan Gunthorpe
2018-03-01 21:25                 ` Jerome Glisse
2018-03-01 21:37               ` Stephen  Bates
2018-03-02 21:38               ` Stephen  Bates
2018-03-02 22:09                 ` Jerome Glisse
2018-03-05 20:36                   ` Stephen  Bates
2018-03-01 20:55         ` Logan Gunthorpe
2018-03-01 18:09     ` Stephen  Bates
2018-03-01 20:32       ` Benjamin Herrenschmidt
2018-03-01 19:21     ` Dan Williams
2018-03-01 19:30       ` Logan Gunthorpe
2018-03-01 20:34       ` Benjamin Herrenschmidt
2018-03-01 20:40         ` Benjamin Herrenschmidt
2018-03-01 20:53           ` Jason Gunthorpe
2018-03-01 20:57             ` Logan Gunthorpe
2018-03-01 22:06             ` Benjamin Herrenschmidt
2018-03-01 22:31               ` Linus Torvalds
2018-03-01 22:34                 ` Benjamin Herrenschmidt
2018-03-02 16:22                   ` Kani, Toshi
2018-03-02 16:57                     ` Linus Torvalds
2018-03-02 17:34                       ` Linus Torvalds
2018-03-02 17:38                       ` Kani, Toshi
2018-03-01 21:37         ` Dan Williams
2018-03-01 21:45           ` Logan Gunthorpe
2018-03-01 21:57             ` Logan Gunthorpe [this message]
2018-03-01 23:00               ` Benjamin Herrenschmidt
2018-03-01 23:19                 ` Logan Gunthorpe
2018-03-01 23:25                   ` Benjamin Herrenschmidt
2018-03-02 21:44                     ` Benjamin Herrenschmidt
2018-03-02 22:24                       ` Logan Gunthorpe
2018-03-01 23:26                   ` Benjamin Herrenschmidt
2018-03-01 23:54                     ` Logan Gunthorpe
2018-03-01 21:03       ` Benjamin Herrenschmidt
2018-03-01 21:11         ` Logan Gunthorpe
2018-03-01 21:18           ` Jerome Glisse
2018-03-01 21:22             ` Logan Gunthorpe
2018-03-01 10:31 ` Sagi Grimberg
2018-03-01 19:33   ` Logan Gunthorpe

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