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

Uladzislau Rezki
2020-06-18T20:03:49Z

On Thu, Jun 18, 2020 at 10:35:27AM -0700, Matthew Wilcox wrote:
> On Thu, Jun 18, 2020 at 07:30:49PM +0200, Uladzislau Rezki wrote:
> > > I'd suggest:
> > >
> > > rcu_lock_acquire(&rcu_callback_map);
> > > trace_rcu_invoke_kfree_bulk_callback(rcu_state.name,
> > > bkvhead[i]->nr_records, bkvhead[i]->records);
> > > if (i == 0) {
> > > kfree_bulk(bkvhead[i]->nr_records,
> > > bkvhead[i]->records);
> > > } else {
> > > for (j = 0; j < bkvhead[i]->nr_records; j++) {
> > > vfree(bkvhead[i]->records[j]);
> > > }
> > > }
> > > rcu_lock_release(&rcu_callback_map);
> > >
> > There are two different trace functions, one for "bulk" tracing
> > messages, and another one is per one call of kfree(), though we use
> > to indicate vfree() call.
> >
> > Probably we can rename it to: trace_rcu_invoke_kvfree_callback();
> >
> > What do you think?
>
> Works for me!
>
OK. I will send out the patch that will rename that trace function
that makes clear that the pointer that is freed can belong to SLAB
or vmalloc.

> > > But I'd also suggest a vfree_bulk be added. There are a few things
> > > which would be better done in bulk as part of the vfree process
> > > (we batch them up already, but i'm sure we could do better).
> >
> > I was thinking to implement of vfree_bulk() API, but i guess it can
> > be done as future work.
> >
> > Does that sound good?
>
> Yes, definitely a future piece of work.
>
You have already been doing it.

Thank you, Matthew :)

--
Vlad Rezki