/*
 * DF-0946 — swap pressure amplifier.
 * Allocates a large chunk to force the kernel to swap, then exits.
 * Intended to run as a background process alongside swap_meta_race.
 */
#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int main(int argc, char **argv) {
    size_t mb = (argc > 1) ? atol(argv[1]) : 3072;
    size_t sz = mb * 1024UL * 1024;
    char *p = malloc(sz);
    if (!p) { perror("malloc"); return 1; }
    /* touch every page to force allocation, then leave resident */
    long pg = sysconf(_SC_PAGESIZE);
    for (size_t i = 0; i < sz; i += pg) p[i] = (char)i;
    printf("[*] pressure amp: %zuMB resident, pid %d, sleeping 60s\n",
           mb, (int)getpid());
    fflush(stdout);
    sleep(60);
    free(p);
    return 0;
}