On Mon, Apr 07, 2014 at 04:07:01PM +0300, Kirill A. Shutemov wrote:
> On Thu, Apr 03, 2014 at 10:48:44PM +0400, Cyrill Gorcunov wrote:
> > Hi! I've been trying to clean up soft-dirty bit usage. I can't cleanup
> > "ridiculous macros in pgtable-2level.h" completely because I need to
> > define _PAGE_FILE,_PAGE_PROTNONE,_PAGE_NUMA bits in sequence manner
> > like
> >
> > #define _PAGE_BIT_FILE (_PAGE_BIT_PRESENT + 1) /* _PAGE_BIT_RW */
> > #define _PAGE_BIT_NUMA (_PAGE_BIT_PRESENT + 2) /* _PAGE_BIT_USER */
> > #define _PAGE_BIT_PROTNONE (_PAGE_BIT_PRESENT + 3) /* _PAGE_BIT_PWT */
> >
> > which can't be done right now because numa code needs to save original
> > pte bits for example in __split_huge_page_map, if I'm not missing something
> > obvious.
>
> Sorry, I didn't get this. How __split_huge_page_map() does depend on pte
> bits order?
__split_huge_page_map
...
for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
...
here we modify with pte bits
entry = pte_mknuma(entry); --> clean _PAGE_PRESENT and set _PAGE_NUMA
pte bits must remain valid and meaningful, for example we might
have set _PAGE_RW here
> > is it intentional, and @prot_numa argument is supposed to be passed
> > with prot_numa = 1 one day, or it's leftover from old times?
>
> I see one more user of change_protection() -- change_prot_numa(), which
> has .prot_numa == 1.
Yeah, thanks, managed to miss this.
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