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 for <linuxppc-dev@lists.ozlabs.org> from <aneesh.kumar@linux.vnet.ibm.com>;
 Sun, 21 Aug 2016 10:15:41 -0600
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Reza Arbab <arbab@linux.vnet.ibm.com>,
 Benjamin Herrenschmidt <benh@kernel.crashing.org>,
 Paul Mackerras <paulus@samba.org>, Michael Ellerman <mpe@ellerman.id.au>,
 Balbir Singh <bsingharora@gmail.com>, linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC v2 0/2] powerpc/mm: enable memory hotplug on radix
In-Reply-To: <1471449083-15931-1-git-send-email-arbab@linux.vnet.ibm.com>
References: <1471449083-15931-1-git-send-email-arbab@linux.vnet.ibm.com>
Date: Sun, 21 Aug 2016 21:45:35 +0530
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Reza Arbab <arbab@linux.vnet.ibm.com> writes:

> Memory hotplug is leading to hash page table calls, even on radix:
>
> ...
> 	arch_add_memory
> 		create_section_mapping
> 			htab_bolt_mapping
> 				BUG_ON(!ppc_md.hpte_insert);
>
> Refactor {create,remove}_section_mapping() into hash__ and radix__ variants.
>
> RFC/TODO:
> I wasn't sure what to do in radix__remove_section_mapping(). Its vmemmap
> counterpart radix__vmemmap_remove_mapping() is stubbed as a FIXME. I left it
> empty for now.

For linear mapping and for vmemmap area we should do something equivalent of

static void __meminit
remove_pagetable(unsigned long start, unsigned long end, bool direct)

as done for x86.

-aneesh