Re: Our "fallback" atomics implementation doesn't actually work - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Our "fallback" atomics implementation doesn't actually work
Date
Msg-id 22366.1475691465@sss.pgh.pa.us
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In response to Re: Our "fallback" atomics implementation doesn't actually work  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> On 2016-10-05 14:01:05 -0400, Tom Lane wrote:
>> I think what is happening is that there are circular assumptions that end
>> up trying to implement a spinlock in terms of a spinlock, or otherwise
>> somehow recursively use the process's semaphore.  It's a bit hard to tell
>> though because the atomics code is such an underdocumented rat's nest of
>> #ifdefs.

> I don't think that should be the case, but I'll look into it.  How long
> did it take for you to reproduce the issue?

It hangs up within 10 or 20 seconds for me.  I didn't try hard to get a
census of where, but at least some of the callers are trying to acquire
buffer partition locks.
        regards, tom lane



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