Re: pserialize(9) vs. TAILQ

[Masao Uebayashi <uebayasi%gmail.com@localhost>]

On Wed, Nov 19, 2014 at 2:53 AM, Taylor R Campbell
<campbell+netbsd-tech-kern%mumble.net@localhost> wrote:
> The one tricky detail is that after a reader has fetched the tqe_next
> pointer, it must issue a membar_consumer before dereferencing the
> pointer: otherwise there is no guarantee about the order in which the
> CPU will fetch the tqe_next pointer and its contents (which it may
> have cached).  Whoever inserts entries must also issue a
> membar_producer after initializing the entry and before inserting it,
> to match the reader's membar_consumer.

Good point.

> Someone^TM should invent names for queue operations that are
> pserialize-safe by virtue of automatically issuing these memory
> barriers: TAILQ_FOREACH_PSZ, TAILQ_INSERT_HEAD_PSZ, &c., or something,
> so that it is easier to use them correctly and spot incorrect use.

I think providing only TAILQ-for-pserialize(9) is enough.  Maybe
PSZQ()?  I don't really mind the name.