Messages in this thread Patch in this message | | | Date | Tue, 2 Dec 2014 10:12:10 +0000 | From | Mel Gorman <> | Subject | Re: [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing |
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On Tue, Dec 02, 2014 at 09:38:39AM +1100, Benjamin Herrenschmidt wrote: > On Fri, 2014-11-21 at 13:57 +0000, Mel Gorman wrote: > > > #ifdef CONFIG_NUMA_BALANCING > > +/* > > + * These work without NUMA balancing but the kernel does not care. See the > > + * comment in include/asm-generic/pgtable.h > > + */ > > +static inline int pte_protnone(pte_t pte) > > +{ > > + return (pte_val(pte) & > > + (_PAGE_PRESENT | _PAGE_USER)) == _PAGE_PRESENT; > > +} > > I would add a comment clarifying that this only works for user pages, > ie, this accessor will always return "true" for a kernel page on ppc. >
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h index 490bd6d..7b889a3 100644 --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h @@ -41,7 +41,8 @@ static inline pgprot_t pte_pgprot(pte_t pte) { return __pgprot(pte_val(pte) & PA #ifdef CONFIG_NUMA_BALANCING /* * These work without NUMA balancing but the kernel does not care. See the - * comment in include/asm-generic/pgtable.h + * comment in include/asm-generic/pgtable.h . On powerpc, this will only + * work for user pages and always return true for kernel pages. */ static inline int pte_protnone(pte_t pte) { -- Mel Gorman SUSE Labs
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