Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when using movable_node

From	Reza Arbab <arbab@linux.vnet.ibm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when using movable_node
Date	2016-10-04 22:30 +0200
Message-ID	<soEvD-7yl-13@gated-at.bofh.it> (permalink)
References	<slmvf-1Fh-7@gated-at.bofh.it> <slmvf-1Fh-13@gated-at.bofh.it> <slLtE-wZ-5@gated-at.bofh.it> <slOhP-2ju-1@gated-at.bofh.it> <som5H-3z4-7@gated-at.bofh.it>
Organization	IBM Linux Technology Center

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On Tue, Oct 04, 2016 at 11:48:30AM +1100, Balbir Singh wrote:
>On 27/09/16 10:14, Reza Arbab wrote:
>> Right. To be clear, the background info I put in the commit log 
>> refers to x86, where the SRAT can describe movable nodes which exist 
>> at boot.  They're trying to avoid allocations from those nodes before 
>> they've been identified.
>>
>> On power, movable nodes can only exist via hotplug, so that scenario 
>> can't happen. We can immediately go back to top-down allocation. That 
>> is the missing call being added in the patch.
>
>Can we fix cmdline_parse_movable_node() to do the right thing? I 
>suspect that code is heavily x86 only in the sense that no other arch 
>needs it.

Good idea. We could change it so things only go bottom-up on x86 in the 
first place.

A nice consequence is that CONFIG_MOVABLE_NODE would then basically be 
usable on any platform with memory hotplug, not just PPC64 and X86_64.

I'll see if I can move the relevant code into an arch_*() call or 
otherwise factor it out.

-- 
Reza Arbab

Thread

[PATCH v3 0/5] powerpc/mm: movable hotplug memory nodes Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-25 20:40 +0200
  [PATCH v3 2/5] drivers/of: do not add memory for unavailable nodes Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-25 20:40 +0200
  [PATCH v3 4/5] powerpc/mm: restore top-down allocation when using movable_node Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-25 20:40 +0200
    Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when using movable_node "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2016-09-26 17:50 +0200
      Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when  using movable_node Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-26 22:50 +0200
    Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when  using movable_node Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-09-26 23:20 +0200
      Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when  using movable_node Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-27 02:20 +0200
        Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when using  movable_node Balbir Singh <bsingharora@gmail.com> - 2016-10-04 02:50 +0200
          Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when  using movable_node Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-10-04 22:30 +0200
  [PATCH v3 3/5] powerpc/mm: allow memory hotplug into a memoryless node Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-25 20:40 +0200
  [PATCH v3 5/5] mm: enable CONFIG_MOVABLE_NODE on powerpc Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-25 20:40 +0200
    Re: [PATCH v3 5/5] mm: enable CONFIG_MOVABLE_NODE on powerpc "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2016-09-26 17:50 +0200
    Re: [PATCH v3 5/5] mm: enable CONFIG_MOVABLE_NODE on powerpc Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-09-26 23:20 +0200
      Re: [PATCH v3 5/5] mm: enable CONFIG_MOVABLE_NODE on powerpc Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-27 02:20 +0200
  [PATCH v3 1/5] drivers/of: introduce of_fdt_is_available() Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-25 20:40 +0200
    Re: [PATCH v3 1/5] drivers/of: introduce of_fdt_is_available() Rob Herring <robh+dt@kernel.org> - 2016-10-03 17:30 +0200

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