/* DF-5253: keep VM page-cache pressure high so file faults stay major. */
#include <sys/mman.h>
#include <stdio.h>
int main(int argc, char **argv){
	size_t len = (argc > 1) ? ((size_t)atoi(argv[1]) << 20) : (1600u<<20);
	char *p = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_ANON, -1, 0);
	if (p == MAP_FAILED) { perror("mmap"); return 1; }
	size_t o; 
	for (o=0;o<len;o+=4096) p[o]=1;
	for(;;){ for (o=0;o<len;o+=4096) p[o]++; }
}