Re: [PATCH] mm, memory_hotplug: support movable_node for hotplugable nodes

From: Wei Yang
Date: Sat Jun 10 2017 - 21:45:54 EST


On Thu, Jun 08, 2017 at 02:23:18PM +0200, Michal Hocko wrote:
>From: Michal Hocko <mhocko@xxxxxxxx>
>
>movable_node kernel parameter allows to make hotplugable NUMA
>nodes to put all the hotplugable memory into movable zone which
>allows more or less reliable memory hotremove. At least this
>is the case for the NUMA nodes present during the boot (see
>find_zone_movable_pfns_for_nodes).
>
>This is not the case for the memory hotplug, though.
>
> echo online > /sys/devices/system/memory/memoryXYZ/status
>
>will default to a kernel zone (usually ZONE_NORMAL) unless the
>particular memblock is already in the movable zone range which is not
>the case normally when onlining the memory from the udev rule context
>for a freshly hotadded NUMA node. The only option currently is to have a
>special udev rule to echo online_movable to all memblocks belonging to
>such a node which is rather clumsy. Not the mention this is inconsistent
>as well because what ended up in the movable zone during the boot will
>end up in a kernel zone after hotremove & hotadd without special care.
>

A kernel zone here means? Which is the counterpart in zone_type? or a
combination of several zone_type?


--
Wei Yang
Help you, Help me

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