Messages in this thread | | | Date | Fri, 26 Aug 2022 11:55:42 -0400 | From | Peter Xu <> | Subject | Re: [PATCH v3 2/3] mm/migrate_device.c: Copy pte dirty bit to page |
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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
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