Re: [PATCH v4 4/5] mm: make processing of movable_node arch-specific
flat view
From: Reza Arbab <hidden>
Date: 2016-10-25 15:55:19
Also in:
linux-devicetree, linux-mm, lkml
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 online_movable.
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 memblock_mark_hotplug()?
Again, this early boot marking mechanism only applies to movable_node. -- Reza Arbab