"swapping of memory" priority

[beroal]

I emulate workload with this simple program in C language, let's call it "use-memory":

#include <malloc.h>
#define SIZE 160000000
int main (void) {
	char *p;
	char *p0;
	int i;
	int a;
	p0 = malloc (SIZE);
	a = 0;
	if (p) {
		while (1) for (i = SIZE, p = p0; (i -= 1000) >= 0;) {
			p[i] = (char) a;
			a++;
		}
	}
	else {
		return (-1);
	}
}

I run N processes. If (N * SIZE > "amount of physical memory in bytes"), then all programs became very slow. Including "bash" and "kill", so even killing of "use-memory" becomes hard. (Do not try N>8.) I think that this is because of intense swapping of memory of "use-memory". The problem is that other programs get swapped too.

I want "memory usage priority", like I/O priority ("ionice") and CPU priority ("chrt"). It should work like this: a program with lower priority may not force to swap memory of a program with higher priority.

[Rubberman]

This is, AFAIK, not a capability in the current kernel(s) of Linux, prioritization of memory usage (swap, vs. in-core). Sounds like you need to think about some kernel modifications, at least on an experimental basis. Hitting the swapper is a known issue with system performance. In fact, real-time systems usually don't support swapping because it negatively affect the determinist performance behavior required by real-time systems.