Subject: Re: [PATCH -V5 06/25] powerpc: Reduce PTE table memory wastage

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Wed, 10 Apr 2013 13:24:59 +0530

Michael Ellerman <[email-masked]> writes:

> On Thu, Apr 04, 2013 at 11:27:44AM +0530, Aneesh Kumar K.V wrote:
>> From: "Aneesh Kumar K.V" <[email-masked]>
>> 
>> We allocate one page for the last level of linux page table. With THP and
>> large page size of 16MB, that would mean we are wasting large part
>> of that page. To map 16MB area, we only need a PTE space of 2K with 64K
>> page size. This patch reduce the space wastage by sharing the page
>> allocated for the last level of linux page table with multiple pmd
>> entries. We call these smaller chunks PTE page fragments and allocated
>> page, PTE page.
>
> This is not compiling for me:
>
> arch/powerpc/mm/mmu_context_hash64.c:118:3: error: implicit declaration of function 'reset_page_mapcount'
>

can you share the .config ? I have the git tree at 

git://github.com/kvaneesh/linux.git ppc64-thp-7

-aneesh