2007-03-21 David Smith <dsmith@redhat.com>

	PR 4146
	* tapsets.cxx (common_probe_entryfn_prologue): Added
	'interruptible' parameter.  If a probe is interruptible,
	interrupts are not disabled while the probe executes.  Preemption
	is disabled however.  Interruptible parameter defaults to false.
	(common_probe_entryfn_epilogue): Ditto.
	(be_derived_probe_group::emit_module_decl): Uses new
	'interruptible' parameter to mark begin/end probes as
	interruptible.
	(probe_derived_probe_group::emit_module): Initialize
	'actionremaining' with MAXACTION instead of initializing
	'actioncount' with 0.
	* translate.cxx (emit_common_header): Renamed 'actioncount' to
	'actionremaining'.  Turned logic around to initialize
	actionremaining to MAXACTION or MAXACTION_INTERRUPTIBLE then
	decrement it as actions occur.
	(translate_pass): Added MAXACTION_INTERRUPTIBLE initialization.
	* translate.h: Removed outdated comment portion.
	* stap.1.in: Documented MAXACTION_INTERRUPTIBLE.
	* NEWS: Added note about begin/end probes being run with
	interrupts enabled.

1 files changed, 11 insertions, 8 deletions

diff --git a/translate.cxx b/translate.cxx
index d3f9467a..e656c5ee 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -808,7 +808,7 @@ c_unparser::emit_common_header ()
   o->newline() << "struct context {";
   o->newline(1) << "atomic_t busy;";
   o->newline() << "const char *probe_point;";
-  o->newline() << "unsigned actioncount;";
+  o->newline() << "int actionremaining;";
   o->newline() << "unsigned nesting;";
   o->newline() << "const char *last_error;";
   // NB: last_error is used as a health flag within a probe.
@@ -2045,9 +2045,9 @@ c_unparser::visit_statement (statement *s, unsigned actions)
 
   if (actions > 0)
     {
-      o->newline() << "c->actioncount += " << actions << ";";
+      o->newline() << "c->actionremaining -= " << actions << ";";
       // XXX: This check is inserted too frequently.
-      o->newline() << "if (unlikely (c->actioncount > MAXACTION)) {";
+      o->newline() << "if (unlikely (c->actionremaining <= 0)) {";
       o->newline(1) << "c->last_error = \"MAXACTION exceeded\";";
       o->newline() << "goto " << outlabel << ";";
       o->newline(-1) << "}";
@@ -2189,9 +2189,9 @@ c_unparser::visit_for_loop (for_loop *s)
   // condition
   o->newline(-1) << toplabel << ":";
 
-  // Emit an explicit actioncount increment here to cover the act of
-  // iteration.  Equivalently, it can stand for the evaluation of the
-  // condition expression.
+  // Emit an explicit action here to cover the act of iteration.
+  // Equivalently, it can stand for the evaluation of the condition
+  // expression.
   o->indent(1);
   visit_statement (0, 1);
 
@@ -2413,8 +2413,8 @@ c_unparser::visit_foreach_loop (foreach_loop *s)
       // condition
       o->newline(-1) << toplabel << ":";
 
-      // Emit an explicit actioncount increment here to cover the act of
-      // iteration.  Equivalently, it can stand for the evaluation of the
+      // Emit an explicit action here to cover the act of iteration.
+      // Equivalently, it can stand for the evaluation of the
       // condition expression.
       o->indent(1);
       visit_statement (0, 1);
@@ -4072,6 +4072,9 @@ translate_pass (systemtap_session& s)
       s.op->newline() << "#ifndef MAXACTION";
       s.op->newline() << "#define MAXACTION 1000";
       s.op->newline() << "#endif";
+      s.op->newline() << "#ifndef MAXACTION_INTERRUPTIBLE";
+      s.op->newline() << "#define MAXACTION_INTERRUPTIBLE (MAXACTION * 10)";
+      s.op->newline() << "#endif";
       s.op->newline() << "#ifndef MAXTRYLOCK";
       s.op->newline() << "#define MAXTRYLOCK MAXACTION";
       s.op->newline() << "#endif";