2005-11-24 Frank Ch. Eigler <fche@redhat.com>

	PR 1917
	* translate.cxx (emit_common_header, emit_module_init,
	emit_module_exit): Switch context array to per-cpu kmalloc variant.
	* tapsets (*::emit_probe_entires): Use per_cpu_ptr() for my context.

diff --git a/ChangeLog b/ChangeLog
index 9062e7939ac9f31fd986fad245e74fbc4933e419..f7b43b697ee03677cc665dd273aee16172c1d592 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2005-11-24  Frank Ch. Eigler  <fche@redhat.com>
+
+       PR 1917
+       * translate.cxx (emit_common_header, emit_module_init,
+       emit_module_exit): Switch context array to per-cpu kmalloc variant.
+       * tapsets (*::emit_probe_entires): Use per_cpu_ptr() for my context.
+
 2005-11-23  Graydon Hoare  <graydon@redhat.com>
 
        * elaborate.h (get_symbol_within_expression): Make visible.

diff --git a/tapsets.cxx b/tapsets.cxx
index fdf1b99932830ee8a5f98893a9588b317f327324..415bc31a807a8599aa578e852068cb58146c214c 100644 (file)
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -146,7 +146,7 @@ be_derived_probe::emit_probe_entries (translator_output* o, unsigned j)
 
       // While begin/end probes are executed single-threaded, we
       // still code defensively and use a per-cpu context.
-      o->newline(1) << "struct context* c = & contexts [smp_processor_id()];";
+      o->newline(1) << "struct context* c = per_cpu_ptr (contexts, smp_processor_id());";
       o->newline() << "const char* probe_point = "
                   << lex_cast_qstring(*l) << ";";
 
@@ -2754,7 +2754,7 @@ dwarf_derived_probe::emit_probe_entries (translator_output* o,
     {
       o->newline() << "int stap_kprobe_fault_handler (struct kprobe* kp, "
                   << "struct pt_regs* regs, int trapnr) {";
-      o->newline(1) << "struct context *c = & contexts [smp_processor_id()];";
+      o->newline(1) << "struct context* c = per_cpu_ptr (contexts, smp_processor_id());";
       o->newline() << "_stp_warn (\"systemtap probe fault\\n\");";
       o->newline() << "_stp_warn (\"cpu %d, probe %s, near %s\\n\", ";
       o->newline(1) << "smp_processor_id(), ";
@@ -2851,7 +2851,7 @@ dwarf_derived_probe::emit_probe_entries (translator_output* o,
   else
     o->line() << "struct kprobe *probe_instance";
   o->line() << ", struct pt_regs *regs) {";
-  o->newline(1) << "struct context *c = & contexts [smp_processor_id()];";
+  o->newline(1) << "struct context* c = per_cpu_ptr (contexts, smp_processor_id());";
 
   // Calculate the name of the current probe by finding its index in the probe array.
   if (has_return)
@@ -3017,7 +3017,7 @@ timer_derived_probe::emit_probe_entries (translator_output* o, unsigned j)
   o->newline() << "static struct timer_list timer_" << j << ";";
 
   o->newline() << "void enter_" << j << " (unsigned long val) {";
-  o->newline(1) << "struct context* c = & contexts [smp_processor_id()];";
+  o->newline(1) << "struct context* c = per_cpu_ptr (contexts, smp_processor_id());";
   o->newline() << "const char* probe_point = "
               << lex_cast_qstring(*locations[0]) << ";";
   o->newline() << "(void) val;";

diff --git a/translate.cxx b/translate.cxx
index 31899120d3ee09f00f2da9f9a74901f0f1f6ae00..e47f285640377c568ff4c21c6a17975807727e79 100644 (file)
--- a/translate.cxx
+++ b/translate.cxx
@@ -856,7 +856,8 @@ c_unparser::emit_common_header ()
       o->newline(-1) << "} function_" << c_varname (fd->name) << ";";
     }
   o->newline(-1) << "} locals [MAXNESTING];";
-  o->newline(-1) << "} contexts [NR_CPUS];" << endl;
+  o->newline(-1) << "};" << endl;
+  o->newline() << "void *contexts; /* alloc_percpu */" << endl;
 
   emit_map_type_instantiations ();
 
@@ -903,8 +904,17 @@ c_unparser::emit_module_init ()
   // while to abort right away.  Currently running probes are allowed to
   // terminate.  These may set STAP_SESSION_ERROR!
 
+  // per-cpu context
+  o->newline() << "contexts = alloc_percpu (struct context);";
+  o->newline() << "if (contexts == NULL) {";
+  o->newline() << "_stp_error (\"percpu context (size %lu) allocation failed\", sizeof (struct context));";
+  o->newline(1) << "rc = -ENOMEM;";
+  o->newline() << "goto out;";
+  o->newline(-1) << "}";
+
   for (unsigned i=0; i<session->globals.size(); i++)
     {
+      // XXX: handle failure!
       vardecl* v = session->globals[i];      
       if (v->index_types.size() > 0)
        o->newline() << getmap (v).init();
@@ -1013,8 +1023,10 @@ c_unparser::emit_module_exit ()
   o->newline() << "do {";
   o->newline(1) << "int i;";
   o->newline() << "holdon = 0;";
-  o->newline() << "for (i=0; i<NR_CPUS; i++)";
-  o->newline(1) << "if (atomic_read (&contexts[i].busy)) holdon = 1;";
+  o->newline() << "for (i=0; i < NR_CPUS; i++)";
+  o->newline(1) << "if (cpu_possible (i) && " 
+                << "atomic_read (& ((struct context *)per_cpu_ptr(contexts, i))->busy)) "
+                << "holdon = 1;";
   // o->newline(-1) << "if (holdon) msleep (5);";
   o->newline(-1) << "} while (holdon);";
   o->newline(-1);
@@ -1022,7 +1034,7 @@ c_unparser::emit_module_exit ()
   // genuinely stuck somehow
 
   for (int i=session->probes.size()-1; i>=0; i--)
-    session->probes[i]->emit_deregistrations (o, i);
+    session->probes[i]->emit_deregistrations (o, i); // NB: runs "end" probes
 
   for (unsigned i=0; i<session->globals.size(); i++)
     {
@@ -1030,6 +1042,9 @@ c_unparser::emit_module_exit ()
       if (v->index_types.size() > 0)
        o->newline() << getmap (v).fini();
     }
+
+  o->newline() << "free_percpu (contexts);";
+
   o->newline(-1) << "}" << endl;
 }