Running 2.4.18 in an embedded system (32MB RAM, no swap), malloc()
goes bye-bye:
/* Malloc as much as possible, then return */
#include <stdio.h>
#define UNIT 1024 /* one kilobyte */
int main ()
{
unsigned int j, totalmalloc=0, totalwrote=0, totalread=0;
while (1) {
unsigned char *buf = (unsigned char *) malloc (UNIT);
if (!buf) return 0;
totalmalloc += UNIT; fprintf (stderr, "%u ", totalmalloc);
for (j=0; j<UNIT; j++) buf[j] = j % 256;
totalwrote += UNIT; fprintf (stderr, "%u ", totalwrote);
for (j=0; j<UNIT; j++) if (buf[j] != (j % 256)) return -1;
totalread += UNIT; fprintf (stderr, "%u\n", totalread);
}
}
I expected this program to malloc most of my embedded MIPS's 32MB of
system RAM, then eventually return with a -1 or a -2. Unfortunately,
it hangs having finally printed:
M26916864
W26916864
R26916864
The malloc call isn't even returning. What could explain that?
I don't have swap space configured, and I notice several kernel
threads that I figure might be assuming I have swap. For example:
3 root S [ksoftirqd_CPU0]
4 root S [kswapd]
5 root S [bdflush]
6 root S [kupdated]
7 root S [mtdblockd]
Do I need any of these if I don't have swap? Are there any special
kernel configs I should be doing if I don't have swap?
Thanks,
Dave
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