Date: Wed, 14 Apr 1999 22:32:26 -0600 From: Warner Losh <imp@harmony.village.org> To: mi@aldan.algebra.com Cc: current@FreeBSD.ORG Subject: Re: swap-related problems Message-ID: <199904150432.WAA07661@harmony.village.org> In-Reply-To: Your message of "Wed, 14 Apr 1999 19:40:07 EDT." <199904142340.TAA96857@misha.cisco.com> References: <199904142340.TAA96857@misha.cisco.com>
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In message <199904142340.TAA96857@misha.cisco.com> Mikhail Teterin writes:
: Then, one can write a safe malloc, which will install the signal
: handler, and touch every page in the the memory referenced by the
: to-be-returned pointer. If the signal handler is invoked in the
: progress, the to-be-returned memory must be returned back to the
: system and NULL should be returned to the caller.
This won't work all the time. FreeBSD overcommits swap space and you
may get a SIGKILL even if you've touched all the pages. FreeBSD kills
processes when swap space runs out.
: However, my (in)ability to propose anything remotely sensible does
: not change the facts established in this painful thread. That our
: malloc does not conform to standards (for whatever reasons), and
: that something should be done about it. That "something" must start
: with documenting the flaw...
The behavior is documented:
The malloc() and calloc() functions return a pointer to the allocated
memory if successful; otherwise a NULL pointer is returned.
What the system does when it has resource shortages is beyond the
scope of the ANSI-C standard, so I don't see why you say that
FreeBSD's malloc isn't standard conforming.
Warner
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