[svlug] Max process size

Marc MERLIN marc_news at valinux.com
Sun May 21 13:57:44 PDT 2000

On dim, mai 21, 2000 at 01:26:10 -0700, Wayne Earl wrote:
> Hello all!
> Can anyone tell me what is the maximum processess size under linux, and if

I believe it's 1 or 2G on IA32 depending on how your kernel was compiled. I
don't remember whether BIGMEM allows you to have more or not.
(you said "under linux", it really depends on the architecture)

> there is a way to increase this number? I can't find anything in the
> kernel source that would indicate a maximum. (this server runs 2.2.12,
> single processor)
> The machine in question has 1GB of RAM, and it appears that processes
> won't go over 256MB in size. (data gathered by running top).

Mmmh, you much have some other problem:
obelix.valinux.com >cat malloc.c 
#include <malloc.h>

int main()
    int i;
    char *ptr;


    printf("\nPointer: %ld\n\n", ptr);

    for (i=0;i<512*1048576;i++)

    return 0;

obelix.valinux.com >./malloc 
             total       used       free     shared    buffers     cached
Mem:       1035404     243108     792296      35556     139520      29664
-/+ buffers/cache:      73924     961480
Swap:       265064          0     265064

Pointer: 1074745352

             total       used       free     shared    buffers     cached
Mem:       1035404     767832     267572      35620     139520      29664
-/+ buffers/cache:     598648     436756
Swap:       265064          0     265064

I just allocated and filled half a gigabyte without problems.
obelix.valinux.com >uname -a
Linux obelix.valinux.com 2.2.14-5.0.14ext3nfs20000320marc3 #1 SMP Wed May 17 16:13:19 PDT 2000 i686 unknown

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