Messages in this thread | | | From | "Aneesh Kumar K.V" <> | Subject | Re: [PATCH] powerpc/mm: update arch_{add,remove}_memory() for radix | Date | Tue, 28 Jun 2016 19:33:06 +0530 |
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Michael Ellerman <mpe@ellerman.id.au> writes:
> On Thu, 2016-06-23 at 14:37 -0500, Reza Arbab wrote: >> On Thu, Jun 23, 2016 at 10:47:20PM +0530, Aneesh Kumar K.V wrote: >> > Reza Arbab <arbab@linux.vnet.ibm.com> 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. > > I think that's more by luck than design. The vmemmap routines use > mmu_vmemmap_psize which is probably but not definitely the same as > mmu_linear_psize. > >> Could it be that the functions just need to be renamed >> hash__create_mapping()/radix__create_mapping() and moved out of #ifdef >> SPARSEMEM_VMEMMAP? > > No, you need to use mmu_linear_psize for the hotplug case. > > But you can probably factor out a common routine that both cases use, and hide > the hash vs radix check in that. > > And probably send me a patch to make MEMORY_HOTPLUG depend on !RADIX for v4.7?
Few other stuff we need to still look from Radix point 1) machine check handling/memory errors 2) kexec
-aneesh
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