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SubjectRe: [PATCHv5 11/19] x86/mm: Implement vma_keyid()
On Wed, Jul 18, 2018 at 04:40:14PM -0700, Dave Hansen wrote:
> > --- a/arch/x86/mm/mktme.c
> > +++ b/arch/x86/mm/mktme.c
> > @@ -1,3 +1,4 @@
> > +#include <linux/mm.h>
> > #include <asm/mktme.h>
> >
> > phys_addr_t mktme_keyid_mask;
> > @@ -37,3 +38,14 @@ struct page_ext_operations page_mktme_ops = {
> > .need = need_page_mktme,
> > .init = init_page_mktme,
> > };
> > +
> > +int vma_keyid(struct vm_area_struct *vma)
> > +{
> > + pgprotval_t prot;
> > +
> > + if (!mktme_enabled())
> > + return 0;
> > +
> > + prot = pgprot_val(vma->vm_page_prot);
> > + return (prot & mktme_keyid_mask) >> mktme_keyid_shift;
> > +}
>
> I'm a bit surprised this isn't inlined. Not that function calls are
> expensive, but we *could* entirely avoid them using the normal pattern of:
>
> // In the header:
> static inline vma_keyid(...)
> {
> if (!mktme_enabled())
> return 0;
>
> return __vma_keyid(...); // <- the .c file version
> }

Okay. I'll do this. But it would be a macros. <asm/mktme.h> gets included
very early. We cannot really use jump label code there directly.

--
Kirill A. Shutemov

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