Re: [PATCH 1/7] General notification queue with user mmap()'able ring buffer

Andrea Parri
2019-05-30T09:50:53Z

> > Looking at the perf ring buffer, there appears to be a missing barrier in
> > perf_aux_output_end():
> >
> > rb->user_page->aux_head = rb->aux_head;
> >
> > should be:
> >
> > smp_store_release(&rb->user_page->aux_head, rb->aux_head);
> >
> > It should also be using smp_load_acquire(). See
> > Documentation/core-api/circular-buffers.rst
> >
> > And a (partial) patch has been proposed: https://lkml.org/lkml/2018/5/10/249
>
> So, if that's all that needs to be fixed, can you use the same
> buffer/code if that patch is merged?

That's about one year old...: let me add the usual suspects in Cc: ;-)
since I'm not sure what the plan was (or if I'm missing something) ...

Speaking of ring buffer implementations (and relatively "old" patches),
here's another quite interesting:

https://lkml.kernel.org/r/20181211034032.32338-1-yuleixzhang@tencent.com

Thanks,
Andrea