static char *workingSet;	// The memory this program wants to acquire.
static int soFar;		// How many pages the program has so far.
static sthread_t refreshThread;

// This thread touches the pages we have in memory, to keep them recently used.
void refresh () {
    int i;

    while (1) {
        // Keep every page in memory recently used.
        for (i = 0; i < soFar; i += PAGESIZE)
            workingSet[i] = 0;
    }
}

int main (int argc, char **argv) {
    // Allocate a giant array.
    workingSet = malloc(ARRAYSIZE);
    soFar = 0;

    // Create a thread to keep our pages in memory, once they get there.
    thread_create(&refreshThread, refresh, 0);

    // Touch every page to bring it into memory.
    for (; soFar < ARRAYSIZE; soFar += PAGESIZE) 
        workingSet[soFar] = 0;

    // Now that everything is in memory, run computation.
    // ...
}