On Fri, Dec 22, 2017 at 4:06 PM, Michael Ellerman <m...@ellerman.id.au> wrote: > Michael Ellerman <m...@ellerman.id.au> writes: > >> When we're using the Radix MMU we map the kernel linear mapping with >> 1G pages. That means we must do memory hot remove in blocks of at >> least that size. Otherwise the linear mapping can end up not mapping >> all of memory because we've removed part of a 1G region but unmapped >> the entire 1G region from the linear mapping. >> >> Currently on pseries we consult the device tree to find out the the >> "LMB" (Logical Memory Block) size. This is the unit of memory hotplug >> communicated to us by the hypervisor, but it does not take into >> account anything the kernel has done itself, such as use 1G pages for >> the linear mapping. > > This patch failed to survive contact with reality. ie. it doesn't work. > > NAK.
I have patches to split the size of a region, I guess the right thing to do is to split the size of mapping during hotplug. I can look at doing that once I am back. What broke for you during testing? Balbir Singh.
