[PATCH 00/31] powerpc/mm: Update page table format for book3s 64

Aneesh Kumar K.V aneesh.kumar at linux.vnet.ibm.com
Tue Sep 22 16:48:17 AEST 2015


Scott Wood <scottwood at freescale.com> writes:

> On Mon, 2015-09-21 at 12:10 +0530, Aneesh Kumar K.V wrote:
>> Hi All,
>> 
>> This patch series attempt to update book3s 64 linux page table format to
>> make it more flexible. Our current pte format is very restrictive and we
>> overload multiple pte bits. This is due to the non-availability of free bits
>> in pte_t. We use pte_t to track the validity of 4K subpages. This patch
>> series free up pte_t of 11 bits by moving 4K subpage tracking to the
>> lower half of PTE page. The pte format is updated such that we have a
>> better method for identifying a pte entry at pmd level. This will also 
>> enable
>> us to implement hugetlb migration(not yet done in this series). 
>> 
>> Before making the changes to the pte format, I am splitting the
>> pte header definition such that we now have the below layout for headers
>> 
>> book3s
>>    32
>>      hash.h pgtable.h 
>>    64
>>      hash.h  pgtable.h hash-4k.h hash-64k.h
>> booke
>>   32
>>      pgtable.h pte-40x.h pte-44x.h pte-8xx.h pte-fsl-booke.h
>>   64
>>     pgtable-4k.h  pgtable-64k.h  pgtable.h
>
> 40x and 8xx are not booke.  Is there a better name that can be used for this 
> directory?  Maybe "nohash", similar to arch/powerpc/mm/tlb_nohash.c?
>

I looked at Documentation/powerpc/cpu_families.txt to name the headers.
It lists then below booke.

-aneesh



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