[RFC PATCH] memory-hotplug: Use dev_online for memhp_auto_offline

Michal Hocko mhocko at kernel.org
Sat Feb 25 03:52:25 AEDT 2017

On Fri 24-02-17 17:40:25, Vitaly Kuznetsov wrote:
> Michal Hocko <mhocko at kernel.org> writes:
> > On Fri 24-02-17 17:09:13, Vitaly Kuznetsov wrote:
> >> While this will most probably work for me I still disagree with the
> >> concept of 'one size fits all' here and the default 'false' for ACPI,
> >> we're taking away the feature from KVM/Vmware folks so they'll again
> >> come up with the udev rule which has known issues.
> >
> > Well, AFAIU acpi_memory_device_add is a standard way how to announce
> > physical memory added to the system. Where does the KVM/VMware depend on
> > this to do memory ballooning?
> As far as I understand memory hotplug in KVM/VMware is pure ACPI memory
> hotplug, there is no specific code for it.

VMware has its ballooning driver AFAIK and I have no idea what KVM uses.
Anyway, acpi_memory_device_add is no different from doing a physical
memory hotplug IIUC so there shouldn't be any difference to how it is

I will post the patch as an RFC sometimes next week, let's see what
others think about it.
Michal Hocko

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