Horton

Re: Add spin_delay() implementation for Arm in s_lock.h

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: "Blake, Geoff" <blakgeof@amazon.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2022-01-07T03:37:31Z
Lists: pgsql-hackers 
On 2022-01-06 22:23:38 -0500, Tom Lane wrote:
> No; there's just one spinlock.  I'm re-purposing the spinlock that
> test_shm_mq uses to protect its setup operations (and thereafter
> ignores).

Oh, sorry, misread :(


> AFAICS the N+1 shm_mq instances don't internally contain
> spinlocks; they all use atomic ops.

They contain spinlocks too, and the naming is similar enough that I got
confused:
struct shm_mq
{
	slock_t		mq_mutex;

We don't use them for all that much anymore though...

Greetings,

Andres Freund

Commits

  1. Use ISB as a spin-delay instruction on ARM64.