---
 This patch adds a support of "overwrite" mode of relayfs.
   When you'd like to use this mode, you just add "-O" to
   the stap command.

 hash.cxx                |    1 +
 main.cxx                |    8 +++++++-
 runtime/transport/utt.c |    4 ++++
 session.h               |    1 +
 translate.cxx           |    3 +++
 5 files changed, 16 insertions(+), 1 deletion(-)

Index: systemtap/runtime/transport/utt.c
===================================================================
--- systemtap.orig/runtime/transport/utt.c	2007-06-18 22:26:38.000000000 +0900
+++ systemtap/runtime/transport/utt.c	2007-06-18 22:30:13.000000000 +0900
@@ -129,7 +129,11 @@
 
 	utt = buf->chan->private_data;
 	atomic_inc(&utt->dropped);
+#ifdef STP_OVERWRITEMODE
+	return 1;
+#else
 	return 0;
+#endif
 }
 
 static int utt_remove_buf_file_callback(struct dentry *dentry)
Index: systemtap/hash.cxx
===================================================================
--- systemtap.orig/hash.cxx	2007-06-18 22:26:38.000000000 +0900
+++ systemtap/hash.cxx	2007-06-18 22:27:24.000000000 +0900
@@ -100,6 +100,7 @@
   h.add(s.merge);			// '-M'
   h.add(s.timing);			// '-t'
   h.add(s.prologue_searching);		// '-P'
+  h.add(s.overwrite_mode);		// '-O'
   for (unsigned i = 0; i < s.macros.size(); i++)
     h.add(s.macros[i]);
 
Index: systemtap/main.cxx
===================================================================
--- systemtap.orig/main.cxx	2007-06-18 22:26:38.000000000 +0900
+++ systemtap/main.cxx	2007-06-18 22:27:24.000000000 +0900
@@ -74,6 +74,7 @@
     << "   -P         prologue-searching for function probes" 
     << (s.prologue_searching ? " [set]" : "") << endl
     << "   -b         bulk (percpu file) mode" << (s.bulk_mode ? " [set]" : "") << endl
+    << "   -O         overwrite buffers mode" << (s.overwrite_mode ? " [set]" : "") << endl
     << "   -s NUM     buffer size in megabytes, instead of "
     << s.buffer_size << endl
     << "   -p NUM     stop after pass NUM 1-5, instead of "
@@ -205,6 +206,7 @@
   s.prologue_searching = false;
 #endif
 
+  s.overwrite_mode = false;
   s.buffer_size = 0;
   s.last_pass = 5;
   s.module_name = "stap_" + stringify(getpid());
@@ -265,7 +267,7 @@
   while (true)
     {
       // NB: also see find_hash(), help(), switch stmt below, stap.1 man page
-      int grc = getopt (argc, argv, "hVMvtp:I:e:o:R:r:m:kgPc:x:D:bs:u");
+      int grc = getopt (argc, argv, "hVMvtp:I:e:o:R:r:m:kgPc:x:D:bs:uO");
       if (grc < 0)
         break;
       switch (grc)
@@ -377,6 +379,10 @@
           s.bulk_mode = true;
           break;
 
+	case 'O':
+	  s.overwrite_mode = true;
+	  break;
+
 	case 'u':
 	  s.unoptimized = true;
 	  break;
Index: systemtap/session.h
===================================================================
--- systemtap.orig/session.h	2007-06-18 22:26:38.000000000 +0900
+++ systemtap/session.h	2007-06-18 22:27:24.000000000 +0900
@@ -97,6 +97,7 @@
   unsigned perfmon;
   bool symtab; /* true: emit symbol table at translation time; false: let staprun do it. */
   bool prologue_searching;
+  bool overwrite_mode;
 
   // Cache data
   bool use_cache;
Index: systemtap/translate.cxx
===================================================================
--- systemtap.orig/translate.cxx	2007-06-18 22:26:38.000000000 +0900
+++ systemtap/translate.cxx	2007-06-18 22:27:24.000000000 +0900
@@ -4319,6 +4319,9 @@
       if (s.bulk_mode)
 	  s.op->newline() << "#define STP_BULKMODE";
 	  
+      if (s.overwrite_mode)
+	  s.op->newline() << "#define STP_OVERWRITEMODE";
+
       if (s.timing)
 	s.op->newline() << "#define STP_TIMING";