| Date | Fri, 29 Jun 2012 11:02:41 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH 06/40] autonuma: x86 pte_numa() and pmd_numa() |
| |
On 06/28/2012 08:55 AM, Andrea Arcangeli wrote:
> static inline int pte_file(pte_t pte) > { > - return pte_flags(pte)& _PAGE_FILE; > + return (pte_flags(pte)& _PAGE_FILE) == _PAGE_FILE; > }
Wait, why is this change made? Surely _PAGE_FILE is just one single bit and this change is not useful?
If there is a reason for this change, please document it.
> @@ -405,7 +405,9 @@ static inline int pte_same(pte_t a, pte_t b) > > static inline int pte_present(pte_t a) > { > - return pte_flags(a)& (_PAGE_PRESENT | _PAGE_PROTNONE); > + /* _PAGE_NUMA includes _PAGE_PROTNONE */ > + return pte_flags(a)& (_PAGE_PRESENT | _PAGE_PROTNONE | > + _PAGE_NUMA_PTE); > } > > static inline int pte_hidden(pte_t pte) > @@ -415,7 +417,46 @@ static inline int pte_hidden(pte_t pte) > > static inline int pmd_present(pmd_t pmd) > { > - return pmd_flags(pmd)& _PAGE_PRESENT; > + return pmd_flags(pmd)& (_PAGE_PRESENT | _PAGE_PROTNONE | > + _PAGE_NUMA_PMD); > +}
Somewhat subtle. Better documentation in patch 5 will help explain this.
> +#ifdef CONFIG_AUTONUMA > +static inline int pte_numa(pte_t pte) > +{ > + return (pte_flags(pte)& > + (_PAGE_NUMA_PTE|_PAGE_PRESENT)) == _PAGE_NUMA_PTE; > +} > + > +static inline int pmd_numa(pmd_t pmd) > +{ > + return (pmd_flags(pmd)& > + (_PAGE_NUMA_PMD|_PAGE_PRESENT)) == _PAGE_NUMA_PMD; > +} > +#endif
These could use a little explanation of how _PAGE_NUMA_* is used and what the flags mean.
> +static inline pte_t pte_mknotnuma(pte_t pte) > +{ > + pte = pte_clear_flags(pte, _PAGE_NUMA_PTE); > + return pte_set_flags(pte, _PAGE_PRESENT|_PAGE_ACCESSED); > +} > + > +static inline pmd_t pmd_mknotnuma(pmd_t pmd) > +{ > + pmd = pmd_clear_flags(pmd, _PAGE_NUMA_PMD); > + return pmd_set_flags(pmd, _PAGE_PRESENT|_PAGE_ACCESSED); > +} > + > +static inline pte_t pte_mknuma(pte_t pte) > +{ > + pte = pte_set_flags(pte, _PAGE_NUMA_PTE); > + return pte_clear_flags(pte, _PAGE_PRESENT); > +} > + > +static inline pmd_t pmd_mknuma(pmd_t pmd) > +{ > + pmd = pmd_set_flags(pmd, _PAGE_NUMA_PMD); > + return pmd_clear_flags(pmd, _PAGE_PRESENT); > }
These functions could use some explanation, too.
Why do the top ones set _PAGE_ACCESSED, while the bottom ones leave _PAGE_ACCESSED alone?
I can guess the answer, but it should be documented so it is also clear to people with less experience in the VM.
-- All rights reversed
|