From: kirill@shutemov.name (Kirill A. Shutemov)
To: linux-snps-arc@lists.infradead.org
Subject: [PATCH V4 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
Date: Mon, 7 Oct 2019 17:00:58 +0300 [thread overview]
Message-ID: <20191007140058.um5g44rvxyzyiref@box> (raw)
In-Reply-To: <20191007135158.GA36360@gmail.com>
On Mon, Oct 07, 2019@03:51:58PM +0200, Ingo Molnar wrote:
>
> * Kirill A. Shutemov <kirill@shutemov.name> wrote:
>
> > On Mon, Oct 07, 2019@03:06:17PM +0200, Ingo Molnar wrote:
> > >
> > > * Anshuman Khandual <anshuman.khandual@arm.com> wrote:
> > >
> > > > This adds a test module which will validate architecture page table helpers
> > > > and accessors regarding compliance with generic MM semantics expectations.
> > > > This will help various architectures in validating changes to the existing
> > > > page table helpers or addition of new ones.
> > > >
> > > > Test page table and memory pages creating it's entries at various level are
> > > > all allocated from system memory with required alignments. If memory pages
> > > > with required size and alignment could not be allocated, then all depending
> > > > individual tests are skipped.
> > >
> > > > diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
> > > > index 52e5f5f2240d..b882792a3999 100644
> > > > --- a/arch/x86/include/asm/pgtable_64_types.h
> > > > +++ b/arch/x86/include/asm/pgtable_64_types.h
> > > > @@ -40,6 +40,8 @@ static inline bool pgtable_l5_enabled(void)
> > > > #define pgtable_l5_enabled() 0
> > > > #endif /* CONFIG_X86_5LEVEL */
> > > >
> > > > +#define mm_p4d_folded(mm) (!pgtable_l5_enabled())
> > > > +
> > > > extern unsigned int pgdir_shift;
> > > > extern unsigned int ptrs_per_p4d;
> > >
> > > Any deep reason this has to be a macro instead of proper C?
> >
> > It's a way to override the generic mm_p4d_folded(). It can be rewritten
> > as inline function + define. Something like:
> >
> > #define mm_p4d_folded mm_p4d_folded
> > static inline bool mm_p4d_folded(struct mm_struct *mm)
> > {
> > return !pgtable_l5_enabled();
> > }
> >
> > But I don't see much reason to be more verbose here than needed.
>
> C type checking? Documentation? Yeah, I know it's just a one-liner, but
> the principle of the death by a thousand cuts applies here.
Okay, if you think it worth it. Anshuman, could you fix it up for the next
submission?
> BTW., any reason this must be in the low level pgtable_64_types.h type
> header, instead of one of the API level header files?
I defined it next pgtable_l5_enabled(). What is more appropriate place to
you? pgtable_64.h? Yeah, it makes sense.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2019-10-07 14:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 5:45 [PATCH V4 0/2] mm/debug: Add tests for architecture exported page table helpers Anshuman Khandual
2019-10-07 5:45 ` [PATCH V4 1/2] mm/hugetlb: Make alloc_gigantic_page() available for general use Anshuman Khandual
2019-10-07 5:45 ` [PATCH V4 2/2] mm/pgtable/debug: Add test validating architecture page table helpers Anshuman Khandual
2019-10-07 13:06 ` Ingo Molnar
2019-10-07 13:26 ` Kirill A. Shutemov
2019-10-07 13:51 ` Ingo Molnar
2019-10-07 14:00 ` Kirill A. Shutemov [this message]
2019-10-08 8:13 ` Anshuman Khandual
2019-10-08 8:07 ` Anshuman Khandual
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