An example which didn't pan out

• The goal is to be able to run mincore

  • Accepts as input the address of an mmap file

  • Returns a byte-vector of which pages are cached in core

  • Possible to optimize code to first read blocks of a file which won't trigger disk IO

• The first step is to mmap a file

require "usr/include/sys/mman.ph"; # for &MAP_FIXED my $file = "/etc/motd"; my $size = -s $file or die; open F, $file or die; my $addr = syscall(&SYS_mmap, 0, $size, &PROT_READ, &MAP_SHARED, fileno F, 0); die "$!\n" unless ($addr > 0);