Out of memory: system();

[Ed K.]

On Fri, 11 Jun 2004, fredex wrote:
> On Fri, Jun 11, 2004 at 01:45:00PM -0400, Ed K. wrote:
>> I have fedora core2 installed with kernel: kernel-2.6.5-1.358
>>
>> I must call system(....) about 300,000 times from a process that has 175MB
>> allocated on a computer with only 256MB of RAM. But after about the 5,000th
>> call, i get an out of memory error (errno: 12 Cannot allocate memory) when
>> I call the system function.
>
> Sounds like a pretty dangerous thing to be doing. You're sure there's
> no better way to design this program?
>
> If you give some more details on what you're doing and why it
> has to be done this way, perhaps someone can ofer some helpful
> suggestions.
>

I don't know how much I can tell about the project, doesn't that suck?
But you can read some of the publicity at:
http://www.phppo.cdc.gov/cyto/CytoView_Demo.asp

Sorry, but you need a windows client to view the demos.

I do have a working test:

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>

int main(int argc, char *argv[])
{
   unsigned char *data;
   int i;

   data=malloc(500*1024*1024);
   memset(data,0,500*1024*1024);

   for (i=0; i<100000; i++)
     system("cat /proc/meminfo");
}

This does not cause problems on FC1 (kernel 2.4.22-1.2188) But does on FC2 (kernel 2.6.5-1.358)

Is this a glibc bug or a kernel bug?

ed

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