[RFC PATCH 1/6] mm/mmu_notifier: Allow multiple struct mmu_interval_notifier passes

[Matthew Brost]

On Mon, Aug 18, 2025 at 06:42:36PM +0200, Thomas Hellström wrote:
> On Mon, 2025-08-18 at 13:36 -0300, Jason Gunthorpe wrote:
> > On Mon, Aug 18, 2025 at 09:25:20AM -0700, Matthew Brost wrote:
> > > I think this choice makes sense: it allows embedding the wait state
> > > from
> > > the initial notifier call into the pass structure. Patch [6] shows
> > > this
> > > by attaching the issued TLB invalidation fences to the pass. Since
> > > a
> > > single notifier may be invoked multiple times with different ranges
> > > but
> > > the same seqno,
> > 
> > That should be explained, but also seems to be a bit of a different
> > issue..
> > 
> > If the design is really to only have two passes and this linked list
> > is about retaining state then there should not be so much freedom to
> > have more passes.
> 
> Actually the initial suggestion was two passes only. Then I thought I
> saw a use-case for even three passes and added the multi-pass thing,
> but I think it turned out we didn't have such a use-case. IMO we could
> restrict it to two-pass. Matthew, that should be completely OK for the
> SVM use-case, right?
> 

Yea, I just replied that 2 passes should be sufficient.

Matt

> /Thomas
> 
> 
> > 
> > Jason
>