On Fri, Aug 24, 2018 at 01:32:14PM +0200, Peter Zijlstra wrote:
> 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")
Ah, good, it seems that already got cleaned up a lot. But it all moved
into the power code.. blergh.
