Re: Little cleanup: Move ProcStructLock to the ProcGlobal struct
Chao Li <li.evan.chao@gmail.com>
From: Chao Li <li.evan.chao@gmail.com>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2026-02-11T03:16:07Z
Lists: pgsql-hackers
> On Feb 11, 2026, at 01:39, Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>
> For some reason, the ProcStructLock spinlock is allocated in a shared memory area of its own:
>
> /* Create ProcStructLock spinlock, too */
> ProcStructLock = (slock_t *) ShmemInitStruct("ProcStructLock spinlock",
> sizeof(slock_t),
> &found);
> SpinLockInit(ProcStructLock);
>
> I believe that's just for historical reasons. A long long time ago, spinlocks had to be allocated separately rather than embedded in other structs.
>
> The spinlock protects the freeProcs list and some other fields in ProcGlobal, so let's put it together with those fields. It's good for cache locality to have it next to the thing it protects, and just makes more sense anyway.
>
> Any objections?
>
> - Heikki<0001-Move-ProcStructLock-to-the-ProcGlobal-struct.patch>
Hi Heikki,
I took a quick review. You moved ProcStructLock into PROC_HDR as freeProcsLock, and deleted:
```
ProcStructLock = ShmemInitStruct(...);
SpinLockInit(ProcStructLock);
```
But I don’t see a replacement like SpinLockInit(&ProcGlobal->freeProcsLock);
Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/
Commits
-
Move ProcStructLock to the ProcGlobal struct
- 7984ce7a1d21 19 (unreleased) landed