Messages in this thread | | | Date | Fri, 24 Aug 2018 13:32:14 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 3/4] mm/tlb, x86/mm: Support invalidating TLB caches for RCU_TABLE_FREE |
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On Fri, Aug 24, 2018 at 10:47:17AM +0200, Peter Zijlstra wrote: > On Thu, Aug 23, 2018 at 02:39:59PM +0100, Will Deacon wrote: > > The only problem with this approach is that we've lost track of the granule > > size by the point we get to the tlb_flush(), so we can't adjust the stride of > > the TLB invalidations for huge mappings, which actually works nicely in the > > synchronous case (e.g. we perform a single invalidation for a 2MB mapping, > > rather than iterating over it at a 4k granule). > > > > One thing we could do is switch to synchronous mode if we detect a change in > > granule (i.e. treat it like a batch failure). > > We could use tlb_start_vma() to track that, I think. Shouldn't be too > hard.
Hurm.. look at commit:
e77b0852b551 ("mm/mmu_gather: track page size with mmu gather and force flush if page size change")
yuck yuck yuck. That needs fixing.
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