Re: [PATCH v2 09/16] rcu/tree: Maintain separate array for vmalloc ptrs

Paul E. McKenney
2020-06-18T19:04:06Z

On Thu, Jun 18, 2020 at 08:34:48PM +0200, Uladzislau Rezki wrote:
> > > >
> > > > I suspect that he would like to keep the tracing.
> > > >
> > > > It might be worth trying the branches, given that they would be constant
> > > > and indexed by "i". The compiler might well remove the indirection.
> > > >
> > > > The compiler guys brag about doing so, which of course might or might
> > > > not have any correlation to a given compiler actually doing so. :-/
> > > >
> > > > Having a vfree_bulk() might well be useful, but I would feel more
> > > > confidence in that if there were other callers of kfree_bulk().
> > > >
> > > Hmm... I think replacing that with vfree_bulk() is a good idea though.
> >
> > In other words, get rid of kfree_bulk() in favor of vfree_bulk()?
> >
> kfree_bulk() does not understand vmalloc memory. vfree_bulk() should
> be implemented to release vmalloc's pointers. On i high level it will
> be used the same way as kfree_bulk() but for vmalloc ptrs. only.

Ah, I thought that you guys were proposing something that did bulk
free of both kmalloc and vmalloc memory.

Thanx, Paul

> > > > But again, either way, future work as far as this series is concerned.
> > > >
> > > What do you mean: is concerned?
> >
> > Apologies for the strange English. How about this?
> >
> > "This series is OK as is. Any comments above did not prevent me from
> > taking these patches, but instead discuss possible future work."
> >
> That is perfectly clear to me :)
>
> > > We are planning to implement kfree_rcu() to be integrated directly into
> > > SLAB: SLAB, SLUB, SLOB. So, there are plenty of future work :)
> >
> > And I am glad that this is still the goal. ;-)
> >
> :)
>
> --
> Vlad Rezki