From owner-freebsd-current  Thu Apr 15  0: 7:26 1999
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Date: Thu, 15 Apr 1999 17:04:58 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199904150704.RAA06774@godzilla.zeta.org.au>
To: green@unixhelp.org, phk@critter.freebsd.dk
Subject: Re: swap-related problems
Cc: current@FreeBSD.ORG, mi@kot.ne.mediaone.net
Sender: owner-freebsd-current@FreeBSD.ORG
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>> Sorry FreeBSD doesn't support resource reservation for memory.
>
>mlock()? BTW, why can't anyone explain why the old behavior WAS THAT
>the process would get NULL? Now it's this...

Implementation quirks (bugs) and races.

brk(2) used to fail when memory (real+swap) is running short, instead
of waiting for the pagers to free some memory (it may be possible to
free almost as much memory as there is real memory, e.g., by forgetting
that pages backed by vnodes are in core).  This tended to cause innocent
processes to exit when malloc() failed.  However, in simple tests where
only one memory hog process is calling malloc(), it only affects the
guilty process.

Bruce


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