Messages in this thread | | | Date | Wed, 31 Oct 2012 11:16:35 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PART3 Patch 00/14] introduce N_MEMORY |
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On Wed, 31 Oct 2012, Wen Congyang wrote:
> From: Lai Jiangshan <laijs@cn.fujitsu.com> > > This patch is part3 of the following patchset: > https://lkml.org/lkml/2012/10/29/319 > > Part1 is here: > https://lkml.org/lkml/2012/10/31/30 > > Part2 is here: > http://marc.info/?l=linux-kernel&m=135166705909544&w=2 > > You can apply this patchset without the other parts. > > we need a node which only contains movable memory. This feature is very > important for node hotplug. So we will add a new nodemask > for all memory. N_MEMORY contains movable memory but N_HIGH_MEMORY > doesn't contain it. > > We don't remove N_HIGH_MEMORY because it can be used to search which > nodes contains memory that the kernel can use. >
This doesn't describe why we need the new node state, unfortunately. It makes sense to boot with node(s) containing only ZONE_MOVABLE, but it doesn't show why we need a nodemask to specify such nodes and such information should be available from the kernel log or /proc/zoneinfo.
Node hotplug should fail if all memory cannot be offlined, so why do we need another nodemask? Only offline the node if all memory is offlined.
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