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-rw-r--r--tapsets.cxx200
1 files changed, 88 insertions, 112 deletions
diff --git a/tapsets.cxx b/tapsets.cxx
index fcf84820..a6c57b80 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -1,5 +1,5 @@
// tapset resolution
-// Copyright (C) 2005 Red Hat Inc.
+// Copyright (C) 2005, 2006 Red Hat Inc.
// Copyright (C) 2005 Intel Corporation.
//
// This file is part of systemtap, and is free software. You can
@@ -86,6 +86,63 @@ lex_cast_qstring(IN const & in)
// ------------------------------------------------------------------------
+
+void
+derived_probe::emit_probe_prologue (translator_output* o,
+ const std::string& statereq)
+{
+ o->newline() << "struct context* c = per_cpu_ptr "
+ << "(contexts, smp_processor_id());";
+ o->newline() << "if (atomic_read (&session_state) != " << statereq << ")";
+ o->newline(1) << "goto probe_epilogue;";
+
+ o->newline(-1) << "if (unlikely (atomic_inc_return (&c->busy) != 1)) {";
+
+ o->newline(1) << "if (atomic_inc_return (& skipped_count) > MAXSKIPPED) {";
+ o->newline(1) << "atomic_set (& session_state, STAP_SESSION_ERROR);";
+ // NB: We don't assume that we can safely call stp_error etc. in such
+ // a reentrant context. But this is OK:
+ o->newline() << "_stp_exit ();";
+ o->newline(-1) << "}";
+
+ o->newline() << "atomic_dec (& c->busy);";
+ o->newline() << "goto probe_epilogue;";
+ o->newline(-1) << "}";
+ o->newline();
+ o->newline() << "c->last_error = 0;";
+ o->newline() << "c->probe_point = probe_point;";
+ o->newline() << "c->nesting = 0;";
+ o->newline() << "c->regs = 0;";
+ o->newline() << "c->actioncount = 0;";
+}
+
+void
+derived_probe::emit_probe_epilogue (translator_output* o)
+{
+ o->newline() << "if (unlikely (c->last_error && c->last_error[0])) {";
+ o->newline(1) << "if (c->last_stmt != NULL)";
+ o->newline(1) << "_stp_softerror (\"%s near %s\", c->last_error, c->last_stmt);";
+ o->newline(-1) << "else";
+ o->newline(1) << "_stp_softerror (\"%s\", c->last_error);";
+ o->indent(-1);
+ o->newline() << "atomic_inc (& error_count);";
+
+ o->newline() << "if (atomic_read (& error_count) > MAXERRORS) {";
+ o->newline(1) << "atomic_set (& session_state, STAP_SESSION_ERROR);";
+ o->newline() << "_stp_exit ();";
+ o->newline(-1) << "}";
+
+ o->newline(-1) << "}";
+
+ o->newline() << "atomic_dec (&c->busy);";
+ o->newline(-1) << "probe_epilogue: ;";
+ o->indent(1);
+}
+
+
+
+
+// ------------------------------------------------------------------------
// begin/end probes are run right during registration / deregistration
// ------------------------------------------------------------------------
@@ -147,40 +204,19 @@ 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 = per_cpu_ptr (contexts, smp_processor_id());";
+ o->indent(1);
o->newline() << "const char* probe_point = "
- << lex_cast_qstring(*l) << ";";
-
- // A precondition for running a probe handler is that we're in STARTING
- // or STOPPING state (not ERROR), and that no one else is already using
- // this context.
- o->newline() << "if (atomic_read (&session_state) != ";
- if (begin) o->line() << "STAP_SESSION_STARTING)";
- else o->line() << "STAP_SESSION_STOPPING)";
- o->newline(1) << "return;";
- o->newline(-1) << "if (atomic_inc_return (&c->busy) != 1) {";
- o->newline(1) << "_stp_warn (\"probe reentrancy (%s vs %s)\\n\", "
- << "c->probe_point, probe_point);";
- o->newline() << "atomic_set (& session_state, STAP_SESSION_ERROR);";
- o->newline() << "atomic_dec (&c->busy);";
- o->newline() << "return;";
- o->newline(-1) << "}";
- o->newline();
- o->newline() << "c->last_error = 0;";
- o->newline() << "c->probe_point = probe_point;";
- o->newline() << "c->nesting = 0;";
- o->newline() << "c->regs = 0;";
- o->newline() << "c->actioncount = 0;";
+ << lex_cast_qstring(*l) << ";";
+ emit_probe_prologue (o,
+ (begin ?
+ "STAP_SESSION_STARTING" :
+ "STAP_SESSION_STOPPING"));
// NB: locals are initialized by probe function itself
o->newline() << "probe_" << j << " (c);";
- o->newline() << "if (c->last_error && c->last_error[0]) {";
- o->newline(1) << "_stp_error (\"%s near %s\", c->last_error, c->last_stmt);";
- o->newline() << "atomic_set (& session_state, STAP_SESSION_ERROR);";
- o->newline(-1) << "}";
+ emit_probe_epilogue (o);
- o->newline() << "atomic_dec (&c->busy);";
o->newline(-1) << "}" << endl;
}
}
@@ -2936,12 +2972,24 @@ dwarf_derived_probe::emit_deregistrations (translator_output* o, unsigned proben
{
o->newline() << "#ifdef ARCH_SUPPORTS_KRETPROBES";
o->newline() << "unregister_kretprobe (&(" << probe_name << "));";
+ o->newline() << "atomic_add ("
+ << probe_name << ".kp.nmissed,"
+ << "& skipped_count);";
+ o->newline() << "atomic_add ("
+ << probe_name << ".nmissed,"
+ << "& skipped_count);";
o->newline() << "#else";
o->newline() << ";";
o->newline() << "#endif";
}
else
- o->newline() << "unregister_kprobe (&(" << probe_name << "));";
+ {
+ o->newline() << "unregister_kprobe (&(" << probe_name << "));";
+ o->newline() << "atomic_add ("
+ << probe_name << ".nmissed,"
+ << "& skipped_count);";
+ }
+
o->indent(-1);
o->newline(-1) << "}";
}
@@ -3053,7 +3101,7 @@ 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 = per_cpu_ptr (contexts, smp_processor_id());";
+ o->indent(1);
// Calculate the name of the current probe by finding its index in the probe array.
if (has_return)
@@ -3064,35 +3112,14 @@ dwarf_derived_probe::emit_probe_entries (translator_output* o,
o->newline() << "const char* probe_point = "
<< string_array
<< "[ (probe_instance - &(" << probe_array << "[0]))];";
-
- // A precondition for running a probe handler is that we're in RUNNING
- // state (not ERROR), and that no one else is already using this context.
- o->newline() << "if (atomic_read (&session_state) != STAP_SESSION_RUNNING)";
- o->newline(1) << "return 0;";
- o->newline(-1) << "if (atomic_inc_return (&c->busy) != 1) {";
- o->newline(1) << "_stp_warn (\"probe reentrancy (%s vs %s)\\n\", "
- << "c->probe_point, probe_point);";
- o->newline() << "atomic_set (& session_state, STAP_SESSION_ERROR);";
- o->newline() << "atomic_dec (&c->busy);";
- o->newline() << "return 0;";
- o->newline(-1) << "}";
- o->newline();
-
- o->newline() << "c->last_error = 0;";
- o->newline() << "c->probe_point = probe_point;";
- o->newline() << "c->nesting = 0;";
+ emit_probe_prologue (o, "STAP_SESSION_RUNNING");
o->newline() << "c->regs = regs;";
- o->newline() << "c->actioncount = 0;";
// NB: locals are initialized by probe function itself
o->newline() << "probe_" << probenum << " (c);";
- o->newline() << "if (c->last_error && c->last_error[0]) {";
- o->newline(1) << "_stp_error (\"%s near %s\", c->last_error, c->last_stmt);";
- o->newline() << "atomic_set (& session_state, STAP_SESSION_ERROR);";
- o->newline(-1) << "}";
+ emit_probe_epilogue (o);
- o->newline() << "atomic_dec (& c->busy);";
o->newline() << "return 0;";
o->newline(-1) << "}" << endl;
if (has_return)
@@ -3244,26 +3271,12 @@ 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 = per_cpu_ptr (contexts, smp_processor_id());";
+ o->indent(1);
o->newline() << "const char* probe_point = "
<< lex_cast_qstring(*locations[0]) << ";";
- o->newline() << "(void) val;";
-
- // A precondition for running a probe handler is that we're in
- // RUNNING state (not ERROR), and that no one else is already using
- // this context.
- o->newline() << "if (atomic_read (&session_state) != STAP_SESSION_RUNNING)";
- o->newline(1) << "return;";
-
- o->newline(-1) << "if (atomic_inc_return (&c->busy) != 1) {";
- o->newline(1) << "_stp_warn (\"probe reentrancy (%s vs %s)\\n\", "
- << "c->probe_point, probe_point);";
- o->newline() << "atomic_set (& session_state, STAP_SESSION_ERROR);";
- o->newline() << "atomic_dec (&c->busy);";
- o->newline() << "return;";
- o->newline(-1) << "}";
- o->newline();
+ emit_probe_prologue (o, "STAP_SESSION_RUNNING");
+ o->newline() << "(void) val;";
o->newline() << "mod_timer (& timer_" << j << ", jiffies + ";
if (time_is_msecs)
o->line() << "msecs_to_jiffies(";
@@ -3274,21 +3287,10 @@ timer_derived_probe::emit_probe_entries (translator_output* o, unsigned j)
o->line() << ")";
o->line() << ");";
- o->newline() << "c->probe_point = probe_point;";
- o->newline() << "c->last_error = 0;";
- o->newline() << "c->nesting = 0;";
- o->newline() << "c->regs = 0;";
- o->newline() << "c->actioncount = 0;";
-
// NB: locals are initialized by probe function itself
o->newline() << "probe_" << j << " (c);";
- o->newline() << "if (c->last_error && c->last_error[0]) {";
- o->newline(1) << "_stp_error (\"%s near %s\", c->last_error, c->last_stmt);";
- o->newline() << "atomic_set (& session_state, STAP_SESSION_ERROR);";
- o->newline(-1) << "}";
-
- o->newline() << "atomic_dec (&c->busy);";
+ emit_probe_epilogue (o);
o->newline(-1) << "}" << endl;
}
@@ -3394,45 +3396,19 @@ profile_derived_probe::emit_probe_entries (translator_output* o, unsigned j)
o->newline() << "int enter_" << j << " (struct pt_regs *regs) {";
}
- o->newline(1) << "struct context* c = per_cpu_ptr (contexts, smp_processor_id());";
+ o->indent(1);
o->newline() << "const char* probe_point = "
<< lex_cast_qstring(*locations[0]) << ";";
+ emit_probe_prologue (o, "STAP_SESSION_RUNNING");
if (using_rpn) {
o->newline() << "(void) self;";
o->newline() << "(void) val;";
}
- // A precondition for running a probe handler is that we're in
- // RUNNING state (not ERROR), and that no one else is already using
- // this context.
- o->newline() << "if (atomic_read (&session_state) != STAP_SESSION_RUNNING)";
- o->newline(1) << "return 0;";
-
- o->newline(-1) << "if (atomic_inc_return (&c->busy) != 1) {";
- o->newline(1) << "_stp_warn (\"probe reentrancy (%s vs %s)\\n\", "
- << "c->probe_point, probe_point);";
- o->newline() << "atomic_set (& session_state, STAP_SESSION_ERROR);";
- o->newline() << "atomic_dec (&c->busy);";
- o->newline() << "return 0;";
- o->newline(-1) << "}";
- o->newline();
-
- o->newline() << "c->probe_point = probe_point;";
- o->newline() << "c->last_error = 0;";
- o->newline() << "c->nesting = 0;";
- o->newline() << "c->regs = regs;";
- o->newline() << "c->actioncount = 0;";
-
- // NB: locals are initialized by probe function itself
o->newline() << "probe_" << j << " (c);";
- o->newline() << "if (c->last_error && c->last_error[0]) {";
- o->newline(1) << "_stp_error (\"%s near %s\", c->last_error, c->last_stmt);";
- o->newline() << "atomic_set (& session_state, STAP_SESSION_ERROR);";
- o->newline(-1) << "}";
-
- o->newline() << "atomic_dec (&c->busy);";
+ emit_probe_epilogue (o);
o->newline() << "return 0;";
o->newline(-1) << "}" << endl;
}
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