On Wed, Oct 07, 2020 at 11:39:30AM -0400, Mathieu Desnoyers wrote: > Moving the membarrier_switch_mm to cover kthread cases was to ensure (2), but > if we > add a p->mm NULL check in the global expedited iteration, I think we would be > OK > leaving the stale runqueue's membarrier state while in lazy tlb state. > > As far as (1) is concerned, I think your idea would work, because as you say > we will > have the proper barriers in kthread use/unuse mm. > > I just wonder whether having this stale membarrier state for lazy tlb is > warranted > performance-wise, as it adds complexity: the rq membarrier state will > therefore not be > relevant when we are in lazy tlb mode. > > Thoughts ?
Well, the way I got here was that I considered the membarrier state update tied to switch_mm(), and in that regard my proposal is a simplification.
