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Date: Thu, 11 Feb 2010 12:22:37 +0800
From: David Xu <davidxu@freebsd.org>
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To: Alexander Leidinger <Alexander@Leidinger.net>
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Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org,
	src-committers@FreeBSD.org, mono@FreeBSD.org
Subject: Re: svn commit: r203657 - head/sys/kern
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Alexander Leidinger wrote:
> Quoting David Xu <davidxu@FreeBSD.org> (from Mon, 8 Feb 2010 07:31:05 
> +0000 (UTC)):
>
>> Author: davidxu
>> Date: Mon Feb  8 07:31:05 2010
>> New Revision: 203657
>> URL: http://svn.freebsd.org/changeset/base/203657
>>
>> Log:
>>   Set waiters flag before checking semaphore's counter,
>>   otherwise we might lose a wakeup. Tested on postgresql database 
>> server.
>
> Uhm... if I ktrace a hanging process and I see some semop()s (I assume 
> it is waiting on some event to happen), where on Linux this process is 
> working correctly, then I would like to test this patch to see if the 
> process still has the same problem?
>
> Or differently asked: this affects the operation of semop(2)?
>
> Bye,
> Alexander.
>
This implementation uses umtx, the one in RELENG_8 uses semop() syscall.
They are unrelated.