From: Nathan Bossart <nathandbossart@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org
Subject: Re: small cleanup for s_lock.h
Date: Tue, 5 May 2026 10:49:30 -0500
Message-ID: <afoRiqyHl0HxhzCB@nathan> (raw)
In-Reply-To: <369933.1777933007@sss.pgh.pa.us>
References: <afkUeI7UhacZ5ZFm@nathan>
<369933.1777933007@sss.pgh.pa.us>
On Mon, May 04, 2026 at 06:16:47PM -0400, Tom Lane wrote:
> Nathan Bossart <nathandbossart@gmail.com> writes:
>> I'd like to rewrite the comment at the top of the file, too, but haven't
>> gotten to that yet. I find it a little misleading, especially because
>> we #error if TAS isn't defined.
>
> No objection in principle to improving that comment, but what did you
> have in mind exactly?
I think the way the comment presents the macros gives a potentially
misleading impression about what you typically need to do to get a new
platform working, and you basically need to read through the whole file to
make sense of what's going on. Some of the macros it mentions have a
default implementation that we use everywhere (e.g., S_INIT_LOCK), and if
you're using gcc, you may be able to just use the __sync_lock_test_and_set
versions. If you _did_ need to add a new section for a new platform, you'd
probably be more interested in defining slock_t, HAS_TEST_AND_TEST/TAS,
S_UNLOCK, SPIN_DELAY, and maybe TAS_SPIN. In fact, you _must_ ensure TAS
is defined or else we'll fail to compile.
Although as I write this e-mail and think about how exactly I'd rewrite the
comment, I grow less confident about doing so...
--
nathan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: nathandbossart@gmail.com, tgl@sss.pgh.pa.us
Subject: Re: small cleanup for s_lock.h
In-Reply-To: <afoRiqyHl0HxhzCB@nathan>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox