Re: [PATCH] powerpc/mm: update arch_{add,remove}_memory() for radix
From: Reza Arbab
Date: Thu Jun 23 2016 - 15:37:54 EST
On Thu, Jun 23, 2016 at 10:47:20PM +0530, Aneesh Kumar K.V wrote:
Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx> writes:
These functions are making direct calls to the hash table APIs,
leading to a BUG() on systems using radix.
Switch them to the vmemmap_{create,remove}_mapping() wrappers, and
move to the __meminit section.
They are really not the same. They can possibly end up using different
base page size. Also vmemmap is available only with SPARSEMEM_VMEMMAP
enabled. Does hotplug depend on sparsemem vmemmap ?
I'm not sure. Maybe it's best if I back up a step and explain what lead
me to this patch. During hotplug, you get
...
arch_add_memory
create_section_mapping
htab_bolt_mapping
BUG_ON(!ppc_md.hpte_insert);
So it seemed to me that I needed a radix equivalent of
create_section_mapping().
After some digging, I found hash__vmemmap_create_mapping() and
radix__vmemmap_create_mapping() did what I needed. I did not notice the
#ifdef SPARSEMEM_VMEMMAP around them.
Hotplug/remove are now working for me as far as I can tell, so I think
the functional change in itself was correct. Hotplug may not depend on
sparsemem vmemmap, but we seem to need a radix create_section_mapping()
regardless.
Could it be that the functions just need to be renamed
hash__create_mapping()/radix__create_mapping() and moved out of #ifdef
SPARSEMEM_VMEMMAP?
--
Reza Arbab