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Date: Thu, 16 Jun 2022 10:44:52 +0200
From: Daniel Bristot de Oliveira <bristot@...nel.org>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: Daniel Bristot de Oliveira <bristot@...nel.org>,
Wim Van Sebroeck <wim@...ux-watchdog.org>,
Guenter Roeck <linux@...ck-us.net>,
Jonathan Corbet <corbet@....net>,
Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <peterz@...radead.org>,
Will Deacon <will@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Marco Elver <elver@...gle.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
"Paul E. McKenney" <paulmck@...nel.org>,
Shuah Khan <skhan@...uxfoundation.org>,
Gabriele Paoloni <gpaoloni@...hat.com>,
Juri Lelli <juri.lelli@...hat.com>,
Clark Williams <williams@...hat.com>,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-trace-devel@...r.kernel.org
Subject: [PATCH V4 10/20] rv/monitor: Add the wwnr monitor skeleton created by dot2k
Per task wakeup while not running (wwnr) monitor, generated by dot2k
with this command line:
$ dot2k -d wwnr.dot -t per_task
The model is:
----- %< -----
digraph state_automaton {
center = true;
size = "7,11";
{node [shape = plaintext, style=invis, label=""] "__init_not_running"};
{node [shape = ellipse] "not_running"};
{node [shape = plaintext] "not_running"};
{node [shape = plaintext] "running"};
"__init_not_running" -> "not_running";
"not_running" [label = "not_running", color = green3];
"not_running" -> "not_running" [ label = "wakeup" ];
"not_running" -> "running" [ label = "switch_in" ];
"running" [label = "running"];
"running" -> "not_running" [ label = "switch_out" ];
{ rank = min ;
"__init_not_running";
"not_running";
}
}
----- >% -----
This model is broken, the reason is that a task can be running in the
processor without being set as RUNNABLE. Think about a task about to
sleep:
1: set_current_state(TASK_UNINTERRUPTIBLE);
2: schedule();
And then imagine an IRQ happening in between the lines one and two,
waking the task up. BOOM, the wakeup will happen while the task is
running.
Q: Why do we need this model, so?
A: To test the reactors.
Cc: Wim Van Sebroeck <wim@...ux-watchdog.org>
Cc: Guenter Roeck <linux@...ck-us.net>
Cc: Jonathan Corbet <corbet@....net>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Will Deacon <will@...nel.org>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Marco Elver <elver@...gle.com>
Cc: Dmitry Vyukov <dvyukov@...gle.com>
Cc: "Paul E. McKenney" <paulmck@...nel.org>
Cc: Shuah Khan <skhan@...uxfoundation.org>
Cc: Gabriele Paoloni <gpaoloni@...hat.com>
Cc: Juri Lelli <juri.lelli@...hat.com>
Cc: Clark Williams <williams@...hat.com>
Cc: linux-doc@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Cc: linux-trace-devel@...r.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@...nel.org>
---
kernel/trace/rv/monitors/wwnr/wwnr.c | 115 +++++++++++++++++++++++++++
kernel/trace/rv/monitors/wwnr/wwnr.h | 38 +++++++++
2 files changed, 153 insertions(+)
create mode 100644 kernel/trace/rv/monitors/wwnr/wwnr.c
create mode 100644 kernel/trace/rv/monitors/wwnr/wwnr.h
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.c b/kernel/trace/rv/monitors/wwnr/wwnr.c
new file mode 100644
index 000000000000..8ba01f0f0df8
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+#include <rv/instrumentation.h>
+#include <rv/da_monitor.h>
+
+#define MODULE_NAME "wwnr"
+
+/*
+ * XXX: include required tracepoint headers, e.g.,
+ * #include <linux/trace/events/sched.h>
+ */
+#include <trace/events/rv.h>
+
+/*
+ * This is the self-generated part of the monitor. Generally, there is no need
+ * to touch this section.
+ */
+#include "wwnr.h"
+
+/*
+ * Declare the deterministic automata monitor.
+ *
+ * The rv monitor reference is needed for the monitor declaration.
+ */
+struct rv_monitor rv_wwnr;
+DECLARE_DA_MON_PER_TASK(wwnr, char);
+
+/*
+ * This is the instrumentation part of the monitor.
+ *
+ * This is the section where manual work is required. Here the kernel events
+ * are translated into model's event.
+ *
+ */
+static void handle_switch_in(void *data, /* XXX: fill header */)
+{
+ struct task_struct *p = /* XXX: how do I get p? */;
+ da_handle_event_wwnr(p, switch_in_wwnr);
+}
+
+static void handle_switch_out(void *data, /* XXX: fill header */)
+{
+ struct task_struct *p = /* XXX: how do I get p? */;
+ da_handle_event_wwnr(p, switch_out_wwnr);
+}
+
+static void handle_wakeup(void *data, /* XXX: fill header */)
+{
+ struct task_struct *p = /* XXX: how do I get p? */;
+ da_handle_event_wwnr(p, wakeup_wwnr);
+}
+
+static int start_wwnr(void)
+{
+ int retval;
+
+ retval = da_monitor_init_wwnr();
+ if (retval)
+ return retval;
+
+ rv_attach_trace_probe("wwnr", /* XXX: tracepoint */, handle_switch_in);
+ rv_attach_trace_probe("wwnr", /* XXX: tracepoint */, handle_switch_out);
+ rv_attach_trace_probe("wwnr", /* XXX: tracepoint */, handle_wakeup);
+
+ return 0;
+}
+
+static void stop_wwnr(void)
+{
+ rv_wwnr.enabled = 0;
+
+ rv_detach_trace_probe("wwnr", /* XXX: tracepoint */, handle_switch_in);
+ rv_detach_trace_probe("wwnr", /* XXX: tracepoint */, handle_switch_out);
+ rv_detach_trace_probe("wwnr", /* XXX: tracepoint */, handle_wakeup);
+
+ da_monitor_destroy_wwnr();
+}
+
+/*
+ * This is the monitor register section.
+ */
+struct rv_monitor rv_wwnr = {
+ .name = "wwnr",
+ .description = "auto-generated wwnr",
+ .start = start_wwnr,
+ .stop = stop_wwnr,
+ .reset = da_monitor_reset_all_wwnr,
+ .enabled = 0,
+};
+
+int register_wwnr(void)
+{
+ rv_register_monitor(&rv_wwnr);
+ return 0;
+}
+
+void unregister_wwnr(void)
+{
+ if (rv_wwnr.enabled)
+ stop_wwnr();
+
+ rv_unregister_monitor(&rv_wwnr);
+}
+
+module_init(register_wwnr);
+module_exit(unregister_wwnr);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("dot2k: auto-generated");
+MODULE_DESCRIPTION("wwnr");
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.h b/kernel/trace/rv/monitors/wwnr/wwnr.h
new file mode 100644
index 000000000000..f3dc160642bf
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.h
@@ -0,0 +1,38 @@
+enum states_wwnr {
+ not_running_wwnr = 0,
+ running_wwnr,
+ state_max_wwnr
+};
+
+enum events_wwnr {
+ switch_in_wwnr = 0,
+ switch_out_wwnr,
+ wakeup_wwnr,
+ event_max_wwnr
+};
+
+struct automaton_wwnr {
+ char *state_names[state_max_wwnr];
+ char *event_names[event_max_wwnr];
+ char function[state_max_wwnr][event_max_wwnr];
+ char initial_state;
+ char final_states[state_max_wwnr];
+};
+
+struct automaton_wwnr automaton_wwnr = {
+ .state_names = {
+ "not_running",
+ "running"
+ },
+ .event_names = {
+ "switch_in",
+ "switch_out",
+ "wakeup"
+ },
+ .function = {
+ { running_wwnr, -1, not_running_wwnr },
+ { -1, not_running_wwnr, -1 },
+ },
+ .initial_state = not_running_wwnr,
+ .final_states = { 1, 0 },
+};
--
2.35.1
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