Messages in this thread | | | Date | Mon, 11 May 2015 15:40:15 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH V3] mm/thp: Split out pmd collpase flush into a separate functions |
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On Mon, 11 May 2015 12:09:30 +0530 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
> Architectures like ppc64 [1] need to do special things while clearing > pmd before a collapse. For them this operation is largely different > from a normal hugepage pte clear. Hence add a separate function > to clear pmd before collapse. After this patch pmdp_* functions > operate only on hugepage pte, and not on regular pmd_t values > pointing to page table. > > [1] ppc64 needs to invalidate all the normal page pte mappings we > already have inserted in the hardware hash page table. But before > doing that we need to make sure there are no parallel hash page > table insert going on. So we need to do a kick_all_cpus_sync() > before flushing the older hash table entries. By moving this to > a separate function we capture these details and mention how it > is different from a hugepage pte clear. > > This patch is a cleanup and only does code movement for clarity. > There should not be any change in functionality. > > ... > > +#ifndef pmd_collapse_flush > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +static inline pmd_t pmd_collapse_flush(struct vm_area_struct *vma, > + unsigned long address, > + pmd_t *pmdp) > +{ > + return pmdp_clear_flush(vma, address, pmdp); > +} > +#else > +static inline pmd_t pmd_collapse_flush(struct vm_area_struct *vma, > + unsigned long address, > + pmd_t *pmdp) > +{ > + BUILD_BUG(); > + return __pmd(0); > +} > +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
You want
#define pmd_collapse_flush pmd_collapse_flush
here, just in case a later header file performs the same test.
> +#endif > +
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