Add readahead.

1 files changed, 37 insertions, 0 deletions

diff --git a/toys/other/readahead.c b/toys/other/readahead.c
new file mode 100644
index 00000000..4edd6516
--- /dev/null
+++ b/toys/other/readahead.c
@@ -0,0 +1,37 @@
+/* readahead.c - preload files into disk cache.
+ *
+ * Copyright 2013 Rob Landley <rob@landley.net>
+ *
+ * No standard.
+
+USE_READAHEAD(NEWTOY(readahead, NULL, TOYFLAG_BIN))
+
+config READAHEAD
+  bool "readahead"
+  default y
+  help
+    usage: readahead FILE...
+
+    Preload files into disk cache.
+*/
+
+#include "toys.h"
+
+#include <sys/syscall.h>
+
+static void do_readahead(int fd, char *name)
+{
+  int rc;
+
+  // Since including fcntl.h doesn't give us the wrapper, use the syscall.
+  // 32 bits takes LO/HI offset (we don't care about endianness of 0).
+  if (sizeof(long) == 4) rc = syscall(__NR_readahead, fd, 0, 0, INT_MAX);
+  else rc = syscall(__NR_readahead, fd, 0, INT_MAX);
+
+  if (rc) perror_msg("readahead: %s", name);
+}
+
+void readahead_main(void)
+{
+  loopfiles(toys.optargs, do_readahead);
+}