On Fri, Aug 26, 2022 at 04:47:22PM +0200, David Hildenbrand wrote: > > To me anon exclusive only shows this mm exclusively owns this page. I > > didn't quickly figure out why that requires different handling on tlb > > flushs. Did I perhaps miss something? > > GUP-fast is the magic bit, we have to make sure that we won't see new > GUP pins, thus the TLB flush. > > include/linux/mm.h:gup_must_unshare() contains documentation. Hmm.. Shouldn't ptep_get_and_clear() (e.g., xchg() on x86_64) already guarantees that no other process/thread will see this pte anymore afterwards? -- Peter Xu
