initial check in

util/unfreeze.cpp

@@ -0,0 +1,49 @@
+#include <iostream>
+#include <cstring>
+#include <cerrno>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+
+using namespace std;
+
+
+int main(int argc, char *argv[])
+try
+{
+      if (argc < 2)
+            throw string("Usage: ") + argv[0] + " <filenames>";
+	  for( int i = 0; i < argc; ++i )
+	  {
+		  //
+		  // Open the file and determint its size.
+		  //
+		  char *fileName = argv[1];
+		  int fd = open(fileName, O_RDONLY);
+		  if (fd < 0)
+				throw strerror(errno);
+		  struct stat st;
+		  if (fstat(fd, &st) < 0)
+				throw strerror(errno);
+		  off_t fileSize = st.st_size;
+		  //
+		  // Request the system to unload the file from the page cache.
+		  //
+		  if (posix_fadvise(fd, 0, fileSize, POSIX_FADV_DONTNEED))
+				throw strerror(errno);
+		  close(fd);
+	  }
+      return 0;
+}
+catch (string str)
+{
+      cout << str << endl;
+      return 1;
+}
+catch (const char *str)
+{
+      cout << str << endl;
+      return 1;
+}
+