Messages in this thread | | | Date | Sat, 18 Dec 2021 11:06:57 +0100 | Subject | Re: [PATCH v1 06/11] mm: support GUP-triggered unsharing via FAULT_FLAG_UNSHARE (!hugetlb) | From | David Hildenbrand <> |
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On 18.12.21 03:42, Linus Torvalds wrote: > On Fri, Dec 17, 2021 at 6:17 PM Linus Torvalds > <torvalds@linux-foundation.org> wrote: >> >> I think the hugepage code should use the exact same logic that the >> regular wp fault code does. > > IOW, I think that this stupid (AND UNTESTED) patch should likely just > fix David's test-case with the hugepage and splice thing.. > > Or at least be somewhat close. But it should be paired with the GUP > side doing the right thing too, of course. Maybe it already does, > maybe it doesn't, I didn't check... > > And maybe there's something subtle about the page_count() of a THP > entry. Again, I can't really claim to have tested this all, but I'm > hoping this makes somebody go "Ahh, now I see what Linus means"
Not the reaction you are hoping for: "Gah, Linus still doesn't see why the page_count is just wrong". :)
See the mail I just wrote, let's get a common understanding of how our check should actually look like.
-- Thanks,
David / dhildenb
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