Re: [PATCH 13 of 66] export maybe_mkwrite

Michal Simek
2011-01-18T14:29:55Z

Andrea Arcangeli wrote:
> Hi Michal,
>
> On Mon, Jan 17, 2011 at 03:14:07PM +0100, Michal Simek wrote:
>> Andrea Arcangeli wrote:
>>> From: Andrea Arcangeli <aarcange@redhat.com>
>>>
>>> huge_memory.c needs it too when it fallbacks in copying hugepages into regular
>>> fragmented pages if hugepage allocation fails during COW.
>>>
>>> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
>>> Acked-by: Rik van Riel <riel@redhat.com>
>>> Acked-by: Mel Gorman <mel@csn.ul.ie>
>> It wasn't good idea to do it. mm/memory.c is used only for system with
>> MMU. System without MMU are broken.
>>
>> Not sure what the right fix is but anyway I think use one ifdef make
>> sense (git patch in attachment).
>
> Can you show the build failure with CONFIG_MMU=n so I can understand
> better? Other places in mm.h depends on pte_t/vm_area_struct/VM_WRITE
> to be defined, if a system is without MMU nobody should call it
> simply. Not saying your patch is wrong, but I'm trying to understand
> how exactly it got broken and the gcc error would show it immediately.
>
> This is only called by memory.o and huge_memory.o and they both are
> built only if MMU=y.

Of course: Look for example at this page:
http://www.monstr.eu/wiki/doku.php?id=log:2011-01-18_11_51_49#linux_next

Thanks,
Michal

--
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian