Re: [PATCH V3 0/4] Define coherent device memory node

From	Balbir Singh <bsingharora@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH V3 0/4] Define coherent device memory node
Date	2017-03-01 04:00 +0100
Message-ID	<tg2EG-4LQ-1@gated-at.bofh.it> (permalink)
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>>> The idea of this patchset was to introduce
>>> the concept of memory that is not necessarily system memory, but is coherent
>>> in terms of visibility/access with some restrictions
>>>
>>
>> Which should be done without special casing the page allocator, cpusets and
>> special casing how cpusets are handled. It's not necessary for any other
>> mechanism used to restrict access to portions of memory such as cpusets,
>> mempolicies or even memblock reservations.
>
> Agreed, I mentioned a limitation that we see a cpusets. I do agree that
> we should reuse any infrastructure we have, but cpusets are more static
> in nature and inheritence compared to the requirements of CDM.
>

Mel, I went back and looked at cpusets and found some limitations that
I mentioned earlier, isolating a particular node requires some amount
of laborious work in terms of isolating all tasks away from the root cpuset
and then creating a hierarchy where the root cpuset is empty and now
belong to a child cpuset that has everything but the node we intend to
ioslate. Even with hardwalling, it does not prevent allocations from
the parent cpuset.

I am trying to understand the concerns that you/Michal/Vlastimil have
so that Anshuman/I/other stake holders can respond to the concerns
in one place if that makes sense. Here are the concerns I have heard
so far

1. Lets not add any overhead to the page allocator path
2. Lets try and keep the allocator changes easy to read/parse
3. Why do we need a NUMA interface?
4. How does this compare with HMM?
5. Why can't we use cpusets?

Would that be a fair set of concerns to address?

@Anshuman/@Srikar/@Aneesh anything else you'd like to add in terms
of concerns/issues? I think it will also make a good discussion thread
for those attending LSF/MM (I am not there) on this topic.

Balbir Singh.

Thread

[PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-15 13:10 +0100
  [PATCH V3 1/4] mm: Define coherent device memory (CDM) node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-15 13:10 +0100
    Re: [PATCH V3 1/4] mm: Define coherent device memory (CDM) node Bob Liu <lliubbo@gmail.com> - 2017-02-17 15:10 +0100
      Re: [PATCH V3 1/4] mm: Define coherent device memory (CDM) node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-21 11:30 +0100
  [PATCH V3 3/4] mm: Add new parameter to get_page_from_freelist() function Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-15 13:10 +0100
  [PATCH V3 2/4] mm: Enable HugeTLB allocation isolation for CDM nodes Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-15 13:10 +0100
  Re: [PATCH V3 0/4] Define coherent device memory node Mel Gorman <mgorman@suse.de> - 2017-02-15 19:30 +0100
    Re: [PATCH V3 0/4] Define coherent device memory node Balbir Singh <bsingharora@gmail.com> - 2017-02-16 23:20 +0100
      Re: [PATCH V3 0/4] Define coherent device memory node Mel Gorman <mgorman@suse.de> - 2017-02-17 10:40 +0100
        Re: [PATCH V3 0/4] Define coherent device memory node Balbir Singh <bsingharora@gmail.com> - 2017-02-21 04:00 +0100
          Re: [PATCH V3 0/4] Define coherent device memory node Balbir Singh <bsingharora@gmail.com> - 2017-03-01 04:00 +0100
            Re: [PATCH V3 0/4] Define coherent device memory node Mel Gorman <mgorman@suse.de> - 2017-03-01 11:40 +0100
              Re: [PATCH V3 0/4] Define coherent device memory node Balbir Singh <bsingharora@gmail.com> - 2017-03-01 12:10 +0100
                Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-03-08 13:20 +0100
                [PATCH 2/2] mm: Change mbind(MPOL_BIND) implementation for CDM nodes Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-03-08 14:30 +0100
    Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-17 12:50 +0100
      Re: [PATCH V3 0/4] Define coherent device memory node Mel Gorman <mgorman@suse.de> - 2017-02-17 14:40 +0100
        Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-21 14:20 +0100
          Re: [PATCH V3 0/4] Define coherent device memory node Jerome Glisse <jglisse@redhat.com> - 2017-02-21 21:20 +0100
            Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-23 09:20 +0100
              Re: [PATCH V3 0/4] Define coherent device memory node Jerome Glisse <jglisse@redhat.com> - 2017-02-23 16:30 +0100
          Re: [PATCH V3 0/4] Define coherent device memory node Michal Hocko <mhocko@kernel.org> - 2017-02-22 10:30 +0100
            Re: [PATCH V3 0/4] Define coherent device memory node Jerome Glisse <jglisse@redhat.com> - 2017-02-22 16:00 +0100
              Re: [PATCH V3 0/4] Define coherent device memory node Michal Hocko <mhocko@kernel.org> - 2017-02-22 18:00 +0100
                Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-03-06 07:00 +0100
            Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-23 10:00 +0100
          Re: [PATCH V3 0/4] Define coherent device memory node Mel Gorman <mgorman@suse.de> - 2017-02-23 17:00 +0100
            Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-03-06 06:20 +0100
      Re: [PATCH V3 0/4] Define coherent device memory node Michal Hocko <mhocko@kernel.org> - 2017-02-21 12:20 +0100
        Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-21 14:50 +0100
          Re: [PATCH V3 0/4] Define coherent device memory node Michal Hocko <mhocko@kernel.org> - 2017-02-22 11:00 +0100
            Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-23 08:00 +0100
              Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-03-05 13:50 +0100
          Re: [PATCH V3 0/4] Define coherent device memory node Bob Liu <liubo95@huawei.com> - 2017-02-24 02:20 +0100
            Re: [PATCH V3 0/4] Define coherent device memory node John Hubbard <jhubbard@nvidia.com> - 2017-02-24 05:40 +0100
            Re: [PATCH V3 0/4] Define coherent device memory node Jerome Glisse <jglisse@redhat.com> - 2017-02-24 06:20 +0100
              Re: [PATCH V3 0/4] Define coherent device memory node Bob Liu <liubo95@huawei.com> - 2017-02-27 03:00 +0100
                Re: [PATCH V3 0/4] Define coherent device memory node Anshuman Khandual <khandual@linux.vnet.ibm.com> - 2017-02-27 06:50 +0100

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