LXR toybox/toys/other/readahead.c

   1/* readahead.c - preload files into disk cache.
   2 *
   3 * Copyright 2013 Rob Landley <rob@landley.net>
   4 *
   5 * No standard.
   6
   7USE_READAHEAD(NEWTOY(readahead, NULL, TOYFLAG_BIN))
   8
   9config READAHEAD
  10  bool "readahead"
  11  default y
  12  help
  13    usage: readahead FILE...
  14
  15    Preload files into disk cache.
  16*/
  17
  18#include "toys.h"
  19
  20#include <sys/syscall.h>
  21
  22static void do_readahead(int fd, char *name)
  23{
  24  int rc;
  25
  26  // Since including fcntl.h doesn't give us the wrapper, use the syscall.
  27  // 32 bits takes LO/HI offset (we don't care about endianness of 0).
  28  if (sizeof(long) == 4) rc = syscall(__NR_readahead, fd, 0, 0, INT_MAX);
  29  else rc = syscall(__NR_readahead, fd, 0, INT_MAX);
  30
  31  if (rc) perror_msg("readahead: %s", name);
  32}
  33
  34void readahead_main(void)
  35{
  36  loopfiles(toys.optargs, do_readahead);
  37}
  38