From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Atomic operations within spinlocks
In-reply-to: <20200604190645.xumymtlefvqgdhfr@alap3.anarazel.de>
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Comments: In-reply-to Andres Freund <andres@anarazel.de>
	message dated "Thu, 04 Jun 2020 12:06:45 -0700"
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Date: Thu, 04 Jun 2020 15:13:29 -0400
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Andres Freund <andres@anarazel.de> writes:
> On 2020-06-04 14:50:40 -0400, Tom Lane wrote:
>> 2. The computed completePasses value would go backwards.  I bet
>> that wouldn't matter too much either, or at least we could teach
>> BgBufferSync to cope.  (I notice the comments therein suggest that
>> it is already designed to cope with completePasses wrapping around,
>> so maybe nothing needs to be done.)

> If we're not concerned about that, then we can remove the
> atomic-inside-spinlock, I think. The only reason for that right now is
> to avoid assuming a wrong pass number.

Hmm.  That might be a less-invasive path to a solution.  I can take
a look, if you don't want to.

			regards, tom lane