On Fri, Apr 12, 2024 at 04:55:31PM +1000, Alistair Popple wrote: > Ok, I think I found the dragons you were talking about earlier for > device-dax. I completely broke that because as you've already pointed > out pmd_trans_huge() won't filter out DAX pages. That's fine for FS DAX > (because the pages are essentially normal pages now anyway), but we > don't have a PMD equivalent of vm_normal_page() which leads to all sorts > of issues for DEVDAX. What about vm_normal_page() depends on the radix level ? Doesn't DEVDAX memory have struct page too? > So I will probably have to add something like that unless we only need > to support large (pmd/pud) mappings of DEVDAX pages on systems with > CONFIG_ARCH_HAS_PTE_SPECIAL in which case I guess we could just filter > based on pte_special(). pte_special should only be used by memory without a struct page, is that what DEVDAX is? Jason
