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SubjectRe: [PATCH v4 4/5] mm: make processing of movable_node arch-specific
On Tue, Oct 25, 2016 at 11:15:40PM +1100, Balbir Singh wrote:
>After the ack, I realized there were some more checks needed, IOW
>questions for you :)

Hey! No takebacks!

The short answer is that neither of these is a concern.

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

>1. Have you checked to see if our memblock allocations spill
>over to probably hotpluggable nodes?

Since our nodes don't exist at boot, we don't have that short window
before the zones are drawn where the node has normal memory, and a
kernel allocation might occur within.

>2. Shouldn't we be marking nodes discovered as movable via

Again, this early boot marking mechanism only applies to movable_node.

Reza Arbab

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