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

[Aneesh Kumar K.V]

"Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com> writes:

> Michael Ellerman <michael at ellerman.id.au> writes:
>
>> On Thu, Apr 04, 2013 at 11:27:44AM +0530, Aneesh Kumar K.V wrote:
>>> From: "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com>
>>> 
>>> 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

22b751c3d0376e86a377e3a0aa2ddbbe9d2eefc1 . Will rebase to latest linus tree.

-aneesh