From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <6c88126b59816363f35ee1d010e720b6@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Fri, 31 Aug 2007 07:41:57 -0400
To: 9fans@cse.psu.edu
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Subject: [9fans] plan 9 overcommits memory?
Topicbox-Message-UUID: b2b9ae46-ead2-11e9-9d60-3106f5b1d025

i was trying to tickle a kernel panic, but instead
i think i found a bug.  this program was run on
a machine with 1800 MB user space available.
(3552/464510 user)

	#include<u.h>
	#include<libc.h>
	
	enum{
		Big	= 1024*1024*1790,
	};
	
	void
	main(void)
	{
		char *p;
		ulong i;
	
		p = malloc(Big);
		if(p == 0)
			sysfatal("malloc: %r");
		memset(p, 0, Big);
		exits("");
	}

the result was

	ladd# out of physical memory; no swap configured
	364: 8.out killed: out of memory

this means that the malloc *succeeded* it wasn't until i forced
the pagefault with the memset that i ran out of memory.  what's
going on here?

- erik