On 01/27/2016 02:41 PM, Henning Schild wrote: > In 4.1 huge page mapping of io memory was introduced, enable ipipe to > handle that when pinning kernel memory. > > change that introduced the feature > 0f616be120c632c818faaea9adcb8f05a7a8601f > > Signed-off-by: Henning Schild <henning.sch...@siemens.com> > --- > arch/x86/mm/fault.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index fd5bbcc..ca1e75b 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -211,11 +211,15 @@ static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, > unsigned long address) > pud_k = pud_offset(pgd_k, address); > if (!pud_present(*pud_k)) > return NULL; > + if (pud_large(*pud)) > + return pud_k; > > pmd = pmd_offset(pud, address); > pmd_k = pmd_offset(pud_k, address); > if (!pmd_present(*pmd_k)) > return NULL; > + if (pmd_large(*pmd)) > + return pmd_k; > > if (!pmd_present(*pmd)) > set_pmd(pmd, *pmd_k); > @@ -400,6 +404,8 @@ static inline int vmalloc_sync_one(pgd_t *pgd, unsigned > long address) > > if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref)) > BUG(); > + if (pud_large(*pud)) > + return 0; > > pmd = pmd_offset(pud, address); > pmd_ref = pmd_offset(pud_ref, address); > @@ -408,6 +414,8 @@ static inline int vmalloc_sync_one(pgd_t *pgd, unsigned > long address) > > if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref)) > BUG(); > + if (pmd_large(*pmd)) > + return 0; > > pte_ref = pte_offset_kernel(pmd_ref, address); > if (!pte_present(*pte_ref)) >
I'm confused. Assuming the purpose of that patch is to exclude huge I/O mappings from pte pinning, why does the changes to the x86_32 version of the vmalloc_sync_one() helper actually prevent such pinning, while the x86_64 version does not? Could you explain the logic behind the changes? -- Philippe. _______________________________________________ Xenomai mailing list Xenomai@xenomai.org http://xenomai.org/mailman/listinfo/xenomai
