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From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: John Hubbard <jhubbard@nvidia.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Anshuman Khandual <khandual@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: mhocko@suse.com, vbabka@suse.cz, mgorman@suse.de,
	minchan@kernel.org, aneesh.kumar@linux.vnet.ibm.com,
	bsingharora@gmail.com, srikar@linux.vnet.ibm.com,
	haren@linux.vnet.ibm.com, jglisse@redhat.com,
	dan.j.williams@intel.com
Subject: Re: [RFC V2 03/12] mm: Change generic FALLBACK zonelist creation process
Date: Wed, 1 Feb 2017 12:16:16 +0530	[thread overview]
Message-ID: <c174cdbe-fb7f-2c0f-7ac5-9f8719a06e0f@linux.vnet.ibm.com> (raw)
In-Reply-To: <79bfd849-8e6c-2f6d-0acf-4256a4137526@nvidia.com>

On 01/31/2017 12:55 PM, John Hubbard wrote:
> On 01/30/2017 05:57 PM, Dave Hansen wrote:
>> On 01/30/2017 05:36 PM, Anshuman Khandual wrote:
>>>> Let's say we had a CDM node with 100x more RAM than the rest of the
>>>> system and it was just as fast as the rest of the RAM.  Would we still
>>>> want it isolated like this?  Or would we want a different policy?
>>>
>>> But then the other argument being, dont we want to keep this 100X more
>>> memory isolated for some special purpose to be utilized by specific
>>> applications ?
>>
>> I was thinking that in this case, we wouldn't even want to bother with
>> having "system RAM" in the fallback lists.  A device who got its memory
>> usage off by 1% could start to starve the rest of the system.  A sane
>> policy in this case might be to isolate the "system RAM" from the
>> device's.
> 
> I also don't like having these policies hard-coded, and your 100x
> example above helps clarify what can go wrong about it. It would be
> nicer if, instead, we could better express the "distance" between nodes
> (bandwidth, latency, relative to sysmem, perhaps), and let the NUMA
> system figure out the Right Thing To Do.
> 
> I realize that this is not quite possible with NUMA just yet, but I
> wonder if that's a reasonable direction to go with this?

That is complete overhaul of the NUMA representation in the kernel. What
CDM attempts is to find a solution with existing NUMA framework and with
as little code change as possible.

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  parent reply	other threads:[~2017-02-01  6:46 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-30  3:35 [RFC V2 00/12] Define coherent device memory node Anshuman Khandual
2017-01-30  3:35 ` [RFC V2 01/12] mm: Define coherent device memory (CDM) node Anshuman Khandual
2017-01-30  3:35 ` [RFC V2 02/12] mm: Isolate HugeTLB allocations away from CDM nodes Anshuman Khandual
2017-01-30 17:19   ` Dave Hansen
2017-01-31  1:03     ` Anshuman Khandual
2017-01-31  1:37       ` Dave Hansen
2017-02-01 13:59         ` Anshuman Khandual
2017-02-01 19:01           ` Dave Hansen
2017-01-30  3:35 ` [RFC V2 03/12] mm: Change generic FALLBACK zonelist creation process Anshuman Khandual
2017-01-30 17:34   ` Dave Hansen
2017-01-31  1:36     ` Anshuman Khandual
2017-01-31  1:57       ` Dave Hansen
2017-01-31  7:25         ` John Hubbard
2017-01-31 18:04           ` Dave Hansen
2017-01-31 19:14             ` David Nellans
2017-02-01  6:56             ` Anshuman Khandual
2017-02-01  6:46           ` Anshuman Khandual [this message]
2017-02-01  6:40         ` Anshuman Khandual
2017-01-30  3:35 ` [RFC V2 04/12] mm: Change mbind(MPOL_BIND) implementation for CDM nodes Anshuman Khandual
2017-01-30  3:35 ` [RFC V2 05/12] cpuset: Add cpuset_inc() inside cpuset_init() Anshuman Khandual
2017-01-30 17:36   ` Dave Hansen
2017-01-30 20:30   ` Mel Gorman
2017-01-31 14:22     ` [RFC] cpuset: Enable changing of top_cpuset's mems_allowed nodemask Anshuman Khandual
2017-01-31 16:00       ` Mel Gorman
2017-02-01  7:31         ` Anshuman Khandual
2017-02-01  8:53           ` Michal Hocko
2017-02-01  9:18           ` Mel Gorman
2017-01-31 14:36     ` [RFC V2 05/12] cpuset: Add cpuset_inc() inside cpuset_init() Vlastimil Babka
2017-01-31 15:30       ` Anshuman Khandual
2017-01-30  3:35 ` [RFC V2 06/12] mm: Exclude CDM nodes from task->mems_allowed and root cpuset Anshuman Khandual
2017-01-30  3:35 ` [RFC V2 07/12] mm: Ignore cpuset enforcement when allocation flag has __GFP_THISNODE Anshuman Khandual
2017-01-30  3:35 ` [RFC V2 08/12] mm: Add new VMA flag VM_CDM Anshuman Khandual
2017-01-30 18:52   ` Jerome Glisse
2017-01-31  4:22     ` Anshuman Khandual
2017-01-31  6:05       ` Jerome Glisse
2017-01-30  3:35 ` [RFC V2 09/12] mm: Exclude CDM marked VMAs from auto NUMA Anshuman Khandual
2017-01-30  3:35 ` [RFC V2 10/12] mm: Ignore madvise(MADV_MERGEABLE) request for VM_CDM marked VMAs Anshuman Khandual
2017-01-30  3:35 ` [RFC V2 11/12] mm: Tag VMA with VM_CDM flag during page fault Anshuman Khandual
2017-01-30 17:51   ` Dave Hansen
2017-01-31  5:10     ` Anshuman Khandual
2017-01-31 17:54       ` Dave Hansen
2017-01-30  3:35 ` [RFC V2 12/12] mm: Tag VMA with VM_CDM flag explicitly during mbind(MPOL_BIND) Anshuman Khandual
2017-01-30 17:54   ` Dave Hansen
2017-01-31  4:36     ` Anshuman Khandual
2017-02-07 18:07       ` Dave Hansen
2017-02-08 14:13         ` Anshuman Khandual
2017-02-08 15:04         ` Jerome Glisse
2017-01-30  3:35 ` [DEBUG 13/21] powerpc/mm: Identify coherent device memory nodes during platform init Anshuman Khandual
2017-01-30  3:35 ` [DEBUG 14/21] powerpc/mm: Create numa nodes for hotplug memory Anshuman Khandual
2017-01-30  3:35 ` [DEBUG 15/21] powerpc/mm: Enable CONFIG_MOVABLE_NODE for PPC64 platform Anshuman Khandual
2017-01-30  3:35 ` [DEBUG 16/21] mm: Enable CONFIG_MOVABLE_NODE on powerpc Anshuman Khandual
2017-01-30  3:35 ` [DEBUG 17/21] mm: Export definition of 'zone_names' array through mmzone.h Anshuman Khandual
2017-01-30  3:35 ` [DEBUG 18/21] mm: Add debugfs interface to dump each node's zonelist information Anshuman Khandual
2017-01-30  3:36 ` [DEBUG 19/21] mm: Add migrate_virtual_range migration interface Anshuman Khandual
2017-01-30  3:36 ` [DEBUG 20/21] drivers: Add two drivers for coherent device memory tests Anshuman Khandual
2017-01-30  3:36 ` [DEBUG 21/21] selftests/powerpc: Add a script to perform random VMA migrations Anshuman Khandual
2017-01-31  5:48 ` [RFC V2 00/12] Define coherent device memory node Anshuman Khandual
2017-01-31  6:15   ` Jerome Glisse

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