Re: [PATCH v3 08/34] ia64: mm: Add p?d_large() definitions

[Steven Price <steven.price@arm.com>]

On 01/03/2019 21:57, Kirill A. Shutemov wrote:
> On Wed, Feb 27, 2019 at 05:05:42PM +0000, Steven Price wrote:
>> walk_page_range() is going to be allowed to walk page tables other than
>> those of user space. For this it needs to know when it has reached a
>> 'leaf' entry in the page tables. This information is provided by the
>> p?d_large() functions/macros.
>>
>> For ia64 leaf entries are always at the lowest level, so implement
>> stubs returning 0.
> 
> Are you sure about this? I see pte_mkhuge defined for ia64 and Kconfig
> contains hugetlb references.
> 

I'm not completely familiar with ia64, but my understanding is that it
doesn't have the situation where a page table walk ends early - there is
always the full depth of entries. The p?d_huge() functions always return 0.

However my understanding is that it does support huge TLB entries, so
when populating the TLB a region larger than a standard page can be mapped.

I'd definitely welcome review by someone more familiar with ia64 to
check my assumptions.

Thanks,

Steve