From owner-freebsd-current  Wed May 29  0: 7:12 2002
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To: Poul-Henning Kamp <phk@critter.freebsd.dk>
Cc: Terry Lambert <tlambert2@mindspring.com>,
	Richard Wenninger <richard@richardw.net>, current@FreeBSD.org
Subject: Re: UMA lock 
In-Reply-To: <10399.1022653079@critter.freebsd.dk> 
Date: Wed, 29 May 2002 00:07:09 -0700
From: Peter Wemm <peter@wemm.org>
Message-Id: <20020529070709.03852380A@overcee.wemm.org>
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Poul-Henning Kamp wrote:
> In message <20020529061540.88CD6380A@overcee.wemm.org>, Peter Wemm writes:
> 
> >As you said, _sleeping_ is the problem.  M_WAITOK means "you may sleep if
> >you like".   ie: it is a time bomb waiting for the right low memory conditio
    n
> >which will then explode with a 100% authentic crash or lock up.
> >
> >Pretend it said M_SLEEPOK instead of M_WAITOK.
> 
> Uhm, I'm actually seeing the opposite behaviour as well: after I
> changed the md(4) driver to use M_NOWAIT I still see malloc/zalloc
> sleeping...

No, this is a bug in UMA.  In certain circumstances, it calls itself
with M_WAITOK even when it itself was called with M_NOWAIT.

Cheers,
-Peter
--
Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5


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