Hillf Danton <hdanton@xxxxxxxx> wrote: > > + smp_store_release(&buf->meta.head, head); > > Add a line of comment for the paring smp_load_acquire(). > I did not find it in 04/11. You won't find smp_load_acquire() - it's not in the kernel, though if you look in the sample, you'll find the corresponding barrier in userspace. Note that there's a further implicit barrier you don't see. I've added the comments: /* Barrier against userspace, ordering data read before tail read */ ring_tail = READ_ONCE(buf->meta.tail); and: /* Barrier against userspace, ordering head update after data write. */ smp_store_release(&buf->meta.head, head); David
