Possible LMB hot unplug bug in 4.13+ kernels

[Daniel Henrique Barboza]

> Unless you (Daniel) think there's some reason lmb_is_removable() is
> incorrectly returning false. But most likely it's correct and there's
> just an unmovable allocation in that range.

I am not educated enough to say that the current behavior is wrong. What I
can say is that in 4.11 and older kernels that supports LMB hot 
plug/unplug I
didn't see this kernel "refusal" to remove a LMB that was just hotplugged.

Assuming that the kernel is behaving as intended, a QEMU guest started with
4Gb of RAM that receives an extra 1Gb of RAM will not unplug this same 1Gb.
It seems off from the user perspective that a recently added memory is being
considered not removable, thus QEMU will need to keep this limitation in 
mind when
dealing with future LMB bugs in 4.13+ kernels.


Thanks,


Daniel