On Fri, Feb 23, 2024 at 03:50:33PM -0800, Dan Williams wrote: > Certainly something like that would have satisified this sanity test use > case. I will note that mm_account_fault() would need some help to figure > out the size of the page table entry that got installed. Maybe > extensions to vm_fault_reason to add VM_FAULT_P*D? That compliments > VM_FAULT_FALLBACK to indicate whether, for example, the fallback went > from PUD to PMD, or all the way back to PTE. ugh, no, it's more complicated than that. look at the recent changes to set_ptes(). we can now install PTEs of many different sizes, depending on the architecture. someday i look forward to supporting all the page sizes on parisc (4k, 16k, 64k, 256k, ... 4G)