Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 24 Jan 2023 11:19:02 +0100 | Subject | Re: [PATCH] mm/khugepaged: Fix ->anon_vma race | From | David Hildenbrand <> |
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On 24.01.23 01:51, Kirill A. Shutemov wrote: > On Mon, Jan 23, 2023 at 12:07:05PM +0100, David Hildenbrand wrote: >>>> commit bedf03416913d88c796288f9dca109a53608c745 >>>> Author: Yang Shi <shy828301@gmail.com> >>>> Date: Wed Sep 7 11:01:44 2022 -0700 >>>> >>>> powerpc/64s/radix: don't need to broadcast IPI for radix pmd collapse flush >>>> The IPI broadcast is used to serialize against fast-GUP, but fast-GUP will >>>> move to use RCU instead of disabling local interrupts in fast-GUP. Using >>>> an IPI is the old-styled way of serializing against fast-GUP although it >>>> still works as expected now. >>>> And fast-GUP now fixed the potential race with THP collapse by checking >>>> whether PMD is changed or not. So IPI broadcast in radix pmd collapse >>>> flush is not necessary anymore. But it is still needed for hash TLB. >>> >>> Okay. But I think tlb_remove_table_sync_one() belongs inside >>> pmdp_collapse_flush(). Collapsing pmd table into huge page without >>> serialization is a bug. They should not be separate. >> >> Agreed. But I wonder if it should be moved into a generic >> pmdp_collapse_flush(), that calls an arch specific __pmdp_collapse_flush(). > > Um? There's no __pmdp_collapse_flush().
Did I imply that there is already one? ;)
-- Thanks,
David / dhildenb
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