Limit physical memory per process

Question

I am writing an algorithm to perform some external memory computations, i.e. where your input data does not fit into main memory and you have to consider the I/O complexity.

Answer 1

As other posters have indicated already, setrlimit is the most probable solution, it controls the limits of all configurable aspects of a process environment. Use this command to see these individual settings on your shell process:

ulimit -a

The ones most pertinent to your scenario in the resulting output are as follows:

data seg size           (kbytes, -d) unlimited
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
virtual memory          (kbytes, -v) unlimited

Checkout the manual page for setrlimit ("man setrlimit"), it can be invoked programmatically from your C/C++ code. I have used it to good effect in the past for controlling stack size limits. (btw, there is no dedicated man page for ulimit, it's actually an embedded bash command, so it's in the bash man page.)