Re: pgsql: Allow Pin/UnpinBuffer to operate in a lockfree manner.

On 2016-04-18 17:12:32 +0300, Alexander Korotkov wrote:
> On Mon, Apr 18, 2016 at 2:34 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> > On Sun, Apr 17, 2016 at 12:01 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > > Andres Freund <andres(at)anarazel(dot)de> writes:
> > >> Allow Pin/UnpinBuffer to operate in a lockfree manner.
> > >
> > > Now that I've had some occasion to look around in bufmgr.c, I am very
> > > unhappy that there are still boatloads of comments talking about a buffer
> > > header's spinlock, when there is in fact no spinlock anymore. Please
> > > expend some effort on making this less confusing for the next hacker.
> > > Maybe make those comments talk about a "lock bit" instead?
> >
> > I was actually going to complain about this, too. I noticed it over
> > the weekend when noodling around with another patch. I'm not sure
> > exactly how it should be revised, but I find the current state of
> > things confusing.
> >
>
> +1
> Do we have consensus on renaming "buffer header spinlock" to "buffer header
> lock bit"?

Personally I think the "spin" part is actually quite relevant, and I
think we shouldn't loose it. It describes concurrency and blocking
behaviour, and how errors need to be handled (i.e. there may not be
any).

Greetings,

Andres Freund