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From: "Richard Seaman, Jr." <lists@tar.com>
To: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>
Date: Fri, 12 Dec 97 10:17:02 -0500
Reply-To: "Richard Seaman, Jr." <lists@tar.com>
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Subject: Virtual Memory Question
Sender: owner-freebsd-hackers@freebsd.org
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If I allocate memory using either malloc or mmap, how do I know if the
address handle I get back can be mapped to physical backing of some
sort (RAM or swap)?

For example, I have a machine with 16MB RAM and 64MB swap.  Using
malloc, I can malloc just about 128MB.  Obviously, thats more than I
can get physical backing for.  Trying to access it all terminates
the process, as would be expected.

For mmap (MAP_ANON with fd -1), I can "allocate" virtual memory totalling
over 3GB.  Same problem.

Or, am I just supposed to be smart enough to not grab too much memory?

Thanks.