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From: Bob Liu <liubo95@huawei.com>
To: Jerome Glisse <jglisse@redhat.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, John Hubbard <jhubbard@nvidia.com>,
	Dan Williams <dan.j.williams@intel.com>,
	David Nellans <dnellans@nvidia.com>,
	Balbir Singh <bsingharora@gmail.com>,
	majiuyue <majiuyue@huawei.com>,
	"xieyisheng (A)" <xieyisheng1@huawei.com>,
	ross.zwisler@linux.intel.com
Subject: Re: [HMM-v25 19/19] mm/hmm: add new helper to hotplug CDM memory region v3
Date: Tue, 5 Sep 2017 09:13:24 +0800	[thread overview]
Message-ID: <7026dfda-9fd0-2661-5efc-66063dfdf6bc@huawei.com> (raw)
In-Reply-To: <20170904155123.GA3161@redhat.com>

On 2017/9/4 23:51, Jerome Glisse wrote:
> On Mon, Sep 04, 2017 at 11:09:14AM +0800, Bob Liu wrote:
>> On 2017/8/17 8:05, Jerome Glisse wrote:
>>> Unlike unaddressable memory, coherent device memory has a real
>>> resource associated with it on the system (as CPU can address
>>> it). Add a new helper to hotplug such memory within the HMM
>>> framework.
>>>
>>
>> Got an new question, coherent device( e.g CCIX) memory are likely reported to OS 
>> through ACPI and recognized as NUMA memory node.
>> Then how can their memory be captured and managed by HMM framework?
>>
> 
> Only platform that has such memory today is powerpc and it is not reported
> as regular memory by the firmware hence why they need this helper.
> 
> I don't think anyone has defined anything yet for x86 and acpi. As this is

Not yet, but now the ACPI spec has Heterogeneous Memory Attribute
Table (HMAT) table defined in ACPI 6.2.
The HMAT can cover CPU-addressable memory types(though not non-cache coherent on-device memory).

Ross from Intel already done some work on this, see:
https://lwn.net/Articles/724562/

arm64 supports APCI also, there is likely more this kind of device when CCIX is out
(should be very soon if on schedule).

> memory on PCIE like interface then i don't expect it to be reported as NUMA
> memory node but as io range like any regular PCIE resources. Device driver
> through capabilities flags would then figure out if the link between the
> device and CPU is CCIX capable if so it can use this helper to hotplug it
> as device memory.
> 

>From my point of view,  Cache coherent device memory will popular soon and reported through ACPI/UEFI.
Extending NUMA policy still sounds more reasonable to me.

--
Thanks,
Bob Liu

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  reply	other threads:[~2017-09-05  1:14 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-17  0:05 [HMM-v25 00/19] HMM (Heterogeneous Memory Management) v25 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 01/19] hmm: heterogeneous memory management documentation v3 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 02/19] mm/hmm: heterogeneous memory management (HMM for short) v5 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 03/19] mm/hmm/mirror: mirror process address space on device with HMM helpers v3 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 04/19] mm/hmm/mirror: helper to snapshot CPU page table v4 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 05/19] mm/hmm/mirror: device page fault handler Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 06/19] mm/memory_hotplug: introduce add_pages Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 07/19] mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory v5 Jérôme Glisse
2018-12-20  8:33   ` Dan Williams
2018-12-20 16:15     ` Jerome Glisse
2018-12-20 16:15       ` Jerome Glisse
2018-12-20 16:47       ` Dan Williams
2018-12-20 16:47         ` Dan Williams
2018-12-20 16:57         ` Jerome Glisse
2018-12-20 16:57           ` Jerome Glisse
2017-08-17  0:05 ` [HMM-v25 08/19] mm/ZONE_DEVICE: special case put_page() for device private pages v4 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 09/19] mm/memcontrol: allow to uncharge page without using page->lru field Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 10/19] mm/memcontrol: support MEMORY_DEVICE_PRIVATE v4 Jérôme Glisse
2017-09-05 17:13   ` Laurent Dufour
2017-09-05 17:21     ` Jerome Glisse
2017-08-17  0:05 ` [HMM-v25 11/19] mm/hmm/devmem: device memory hotplug using ZONE_DEVICE v7 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 12/19] mm/hmm/devmem: dummy HMM device for ZONE_DEVICE memory v3 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 13/19] mm/migrate: new migrate mode MIGRATE_SYNC_NO_COPY Jérôme Glisse
2017-08-17 21:12   ` Andrew Morton
2017-08-17 21:44     ` Jerome Glisse
2017-08-17  0:05 ` [HMM-v25 14/19] mm/migrate: new memory migration helper for use with device memory v5 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 15/19] mm/migrate: migrate_vma() unmap page from vma while collecting pages Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 16/19] mm/migrate: support un-addressable ZONE_DEVICE page in migration v3 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 17/19] mm/migrate: allow migrate_vma() to alloc new page on empty entry v4 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 18/19] mm/device-public-memory: device memory cache coherent with CPU v5 Jérôme Glisse
2017-08-17  0:05 ` [HMM-v25 19/19] mm/hmm: add new helper to hotplug CDM memory region v3 Jérôme Glisse
2017-09-04  3:09   ` Bob Liu
2017-09-04 15:51     ` Jerome Glisse
2017-09-05  1:13       ` Bob Liu [this message]
2017-09-05  2:38         ` Jerome Glisse
2017-09-05  3:50           ` Bob Liu
2017-09-05 13:50             ` Jerome Glisse
2017-09-05 16:18               ` Dan Williams
2017-09-05 19:00               ` Ross Zwisler
2017-09-05 19:20                 ` Jerome Glisse
2017-09-08 19:43                   ` Ross Zwisler
2017-09-08 20:29                     ` Jerome Glisse
2017-09-05 18:54           ` Ross Zwisler
2017-09-06  1:25             ` Bob Liu
2017-09-06  2:12               ` Jerome Glisse
2017-09-07  2:06                 ` Bob Liu
2017-09-07 17:00                   ` Jerome Glisse
2017-09-07 17:27                   ` Jerome Glisse
2017-09-08  1:59                     ` Bob Liu
2017-09-08 20:43                       ` Dan Williams
2017-11-17  3:47                         ` chetan L
2017-09-05  3:36       ` Balbir Singh
2017-08-17 21:39 ` [HMM-v25 00/19] HMM (Heterogeneous Memory Management) v25 Andrew Morton
2017-08-17 21:55   ` Jerome Glisse
2017-08-17 21:59     ` Dan Williams
2017-08-17 22:02       ` Jerome Glisse
2017-08-17 22:06         ` Dan Williams
2017-08-17 22:16       ` Andrew Morton
2017-12-13 12:10 ` Figo.zhang
2017-12-13 16:12   ` Jerome Glisse
2017-12-14  2:48     ` Figo.zhang
2017-12-14  3:16       ` Jerome Glisse
2017-12-14  3:53         ` Figo.zhang
2017-12-14  4:16           ` Jerome Glisse
2017-12-14  7:05             ` Figo.zhang
2017-12-14 15:28               ` Jerome Glisse

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