Re: [PATCH v2 4/6] x86: Add clear_page_nocache

[H. Peter Anvin]

On 08/09/2012 08:03 AM, Kirill A. Shutemov wrote:
> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
>
> Add a cache avoiding version of clear_page. Straight forward integer variant
> of the existing 64bit clear_page, for both 32bit and 64bit.
>
> Also add the necessary glue for highmem including a layer that non cache
> coherent architectures that use the virtual address for flushing can
> hook in. This is not needed on x86 of course.
>
> If an architecture wants to provide cache avoiding version of clear_page
> it should to define ARCH_HAS_USER_NOCACHE to 1 and implement
> clear_page_nocache() and clear_user_highpage_nocache().

Compile failure:

/home/hpa/kernel/tip.x86-mm/arch/x86/mm/fault.c: In function 
âclear_user_highpage_nocacheâ:
/home/hpa/kernel/tip.x86-mm/arch/x86/mm/fault.c:1215:30: error: 
âKM_USER0â undeclared (first use in this function)
/home/hpa/kernel/tip.x86-mm/arch/x86/mm/fault.c:1215:30: note: each 
undeclared identifier is reported only once for each function it appears in
/home/hpa/kernel/tip.x86-mm/arch/x86/mm/fault.c:1215:2: error: too many 
arguments to function âkmap_atomicâ
In file included from 
/home/hpa/kernel/tip.x86-mm/include/linux/pagemap.h:10:0,
                 from 
/home/hpa/kernel/tip.x86-mm/include/linux/mempolicy.h:70,
                 from 
/home/hpa/kernel/tip.x86-mm/include/linux/hugetlb.h:15,
                 from /home/hpa/kernel/tip.x86-mm/arch/x86/mm/fault.c:14:
/home/hpa/kernel/tip.x86-mm/include/linux/highmem.h:66:21: note: 
declared here
make[4]: *** [arch/x86/mm/fault.o] Error 1
make[3]: *** [arch/x86/mm] Error 2
make[2]: *** [arch/x86] Error 2
make[1]: *** [sub-make] Error 2
make[1]: Leaving directory `/home/hpa/kernel/tip.x86-mm'

This happens on *all* my test configurations, including both x86-64 and 
i386 allyesconfig.  I suspect your patchset base is stale.

	-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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