Messages in this thread | | | Date | Thu, 3 Aug 2017 16:27:36 +0100 | From | Will Deacon <> | Subject | Re: [PATCH -v2 1/4] mm: Rework {set,clear,mm}_tlb_flush_pending() |
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On Wed, Aug 02, 2017 at 01:38:38PM +0200, Peter Zijlstra wrote: > Commit: > > af2c1401e6f9 ("mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates") > > added smp_mb__before_spinlock() to set_tlb_flush_pending(). I think we > can solve the same problem without this barrier. > > If instead we mandate that mm_tlb_flush_pending() is used while > holding the PTL we're guaranteed to observe prior > set_tlb_flush_pending() instances. > > For this to work we need to rework migrate_misplaced_transhuge_page() > a little and move the test up into do_huge_pmd_numa_page(). > > NOTE: this relies on flush_tlb_range() to guarantee: > > (1) it ensures that prior page table updates are visible to the > page table walker and > (2) it ensures that subsequent memory accesses are only made > visible after the invalidation has completed
Works for me:
Acked-by: Will Deacon <will.deacon@arm.com>
Will
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