On Fri, Mar 01, 2019 at 01:49:53PM +0200, Mike Rapoport wrote:

Hi Kirill,

On Thu, Feb 21, 2019 at 05:57:06PM +0300, Kirill A. Shutemov wrote:

quoted

On Thu, Feb 21, 2019 at 02:46:18PM +0000, Steven Price wrote:

quoted

On 21/02/2019 14:28, Kirill A. Shutemov wrote:

quoted

On Thu, Feb 21, 2019 at 11:34:52AM +0000, Steven Price wrote:

quoted

From: James Morse <james.morse@arm.com>

Exposing the pud/pgd levels of the page tables to walk_page_range() means
we may come across the exotic large mappings that come with large areas
of contiguous memory (such as the kernel's linear map).

For architectures that don't provide p?d_large() macros, provided a
does nothing default.

Nak, sorry.

Power will get broken by the patch. It has pmd_large() inline function,
that will be overwritten by the define from this patch.

I believe it requires more ground work on arch side in general.
All architectures that has huge page support has to provide these helpers
(and matching defines) before you can use it in a generic code.

Sorry about that, I had compile tested on power, but obviously not the
right config to actually see the breakage.

I don't think you'll catch it at compile-time. It would silently override
the helper with always-false.

Can you explain why the compiler would override the helper define in, e.g.
arch/powerpc/include/asm/pgtable.h with the generic (0)?

This one will not be overrided, but the other one will. See

arch/powerpc/include/asm/book3s/64/pgtable.h

-- 
 Kirill A. Shutemov

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel