Messages in this thread | | | Date | Tue, 25 Oct 2016 19:49:29 -0500 | From | Reza Arbab <> | Subject | Re: [PATCH v4 4/5] mm: make processing of movable_node arch-specific |
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On Wed, Oct 26, 2016 at 09:34:18AM +1100, Balbir Singh wrote: >I still believe we need your changes, I was wondering if we've tested >it against normal memory nodes and checked if any memblock >allocations end up there. Michael showed me some memblock >allocations on node 1 of a two node machine with movable_node
The movable_node option is x86-only. Both of those nodes contain normal memory, so allocations on both are allowed.
>> Longer; if you use "movable_node", x86 can identify these nodes at >> boot. They call memblock_mark_hotplug() while parsing the SRAT. Then, >> when the zones are initialized, those markings are used to determine >> ZONE_MOVABLE. >> >> We have no analog of this SRAT information, so our movable nodes can >> only be created post boot, by hotplugging and explicitly onlining >> with online_movable. > >Is this true for all of system memory as well or only for nodes >hotplugged later?
As far as I know, power has nothing like the SRAT that tells us, at boot, which memory is hotpluggable. So there is nothing to wire the movable_node option up to.
Of course, any memory you hotplug afterwards is, by definition, hotpluggable. So we can still create movable nodes that way.
-- Reza Arbab
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