LWLock/ShmemIndex startup question

From: Claudio Natoli <claudio(dot)natoli(at)memetrics(dot)com>
To: "'pgsql-hackers(at)postgresql(dot)org'" <pgsql-hackers(at)postgresql(dot)org>
Subject: LWLock/ShmemIndex startup question
Date: 2004-01-12 09:11:29
Message-ID: A02DEC4D1073D611BAE8525405FCCE2B55F253@harris.memetrics.local
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In CreateSharedMemoryAndSemaphores, there is the following comment, just
before CreateLWLocks():

/*
* Now initialize LWLocks, which do shared memory allocation and are
* needed for InitShmemIndex.
*/

Also, in InitShmemAllocation, there is:

/* ShmemIndex can't be set up yet (need LWLocks first) */

Are these comments still true? Specifically, is it necessary to call
CreateLWLocks before InitShmemIndex? I think it used to be, but then the
ShmemIndexLock got made into a separate spinlock in its own right.

It doesn't appear to be true, and I'd like to rearrange this section of the
code, as part of a possible solution to a Win32 shmem/semaphore bootstrap
problem (postgres semaphores under Win32 uses ShmemIndex which uses
spinlocks which use shared memory which use semaphores which ...).

If ok, I was specifically thinking of rolling the ShmemIndex initialization
into InitShmemAllocation, which I suspect used to do this anyway... any
complaints?

Cheers,
Claudio

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