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Message-Id: <1e9fc63b7e380ef0340b55f8dfb9535dec8087cb.1621414942.git.bristot@redhat.com>
Date: Wed, 19 May 2021 13:36:31 +0200
From: Daniel Bristot de Oliveira <bristot@...hat.com>
To: linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>
Cc: Tommaso Cucinotta <tommaso.cucinotta@...tannapisa.it>,
Kate Carcia <kcarcia@...hat.com>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Jonathan Corbet <corbet@....net>,
Ingo Molnar <mingo@...hat.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <peterz@...radead.org>,
Will Deacon <will@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
"Paul E. McKenney" <paulmck@...nel.org>,
Joel Fernandes <joel@...lfernandes.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Gabriele Paoloni <gabriele.paoloni@...el.com>,
Juri Lelli <juri.lelli@...hat.com>,
Clark Williams <williams@...hat.com>, linux-doc@...r.kernel.org
Subject: [RFC PATCH 10/16] rv/monitors: 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: Jonathan Corbet <corbet@....net>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>
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: "Paul E. McKenney" <paulmck@...nel.org>
Cc: Joel Fernandes <joel@...lfernandes.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc: Gabriele Paoloni <gabriele.paoloni@...el.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
Signed-off-by: Daniel Bristot de Oliveira <bristot@...hat.com>
---
kernel/trace/rv/monitors/wwnr/model.h | 38 ++++++++
kernel/trace/rv/monitors/wwnr/wwnr.c | 127 ++++++++++++++++++++++++++
kernel/trace/rv/monitors/wwnr/wwnr.h | 70 ++++++++++++++
3 files changed, 235 insertions(+)
create mode 100644 kernel/trace/rv/monitors/wwnr/model.h
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/model.h b/kernel/trace/rv/monitors/wwnr/model.h
new file mode 100644
index 000000000000..7840ffbda98d
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/model.h
@@ -0,0 +1,38 @@
+enum states_wwnr {
+ not_running = 0,
+ running,
+ state_max
+};
+
+enum events_wwnr {
+ switch_in = 0,
+ switch_out,
+ wakeup,
+ event_max
+};
+
+struct automaton_wwnr {
+ char *state_names[state_max];
+ char *event_names[event_max];
+ char function[state_max][event_max];
+ char initial_state;
+ char final_states[state_max];
+};
+
+struct automaton_wwnr automaton_wwnr = {
+ .state_names = {
+ "not_running",
+ "running"
+ },
+ .event_names = {
+ "switch_in",
+ "switch_out",
+ "wakeup"
+ },
+ .function = {
+ { running, -1, not_running },
+ { -1, not_running, -1 },
+ },
+ .initial_state = not_running,
+ .final_states = { 1, 0 },
+};
\ No newline at end of file
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.c b/kernel/trace/rv/monitors/wwnr/wwnr.c
new file mode 100644
index 000000000000..91cb3b70a6a7
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.c
@@ -0,0 +1,127 @@
+#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/da_monitor.h>
+
+#define MODULE_NAME "wwnr"
+
+/*
+ * This is the self-generated part of the monitor. Generally, there is no need
+ * to touch this section.
+ */
+#include "model.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);
+
+#define CREATE_TRACE_POINTS
+#include "wwnr.h"
+
+/*
+ * 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.
+ *
+ */
+
+void handle_switch_in(void *data, /* XXX: fill header */)
+{
+ pid_t pid = /* XXX how do I get the pid? */;
+ da_handle_event_wwnr(pid, switch_in);
+}
+
+void handle_switch_out(void *data, /* XXX: fill header */)
+{
+ pid_t pid = /* XXX how do I get the pid? */;
+ da_handle_event_wwnr(pid, switch_out);
+}
+
+void handle_wakeup(void *data, /* XXX: fill header */)
+{
+ pid_t pid = /* XXX how do I get the pid? */;
+ da_handle_event_wwnr(pid, wakeup);
+}
+
+#define NR_TP 3
+static struct tracepoint_hook_helper tracepoints_to_hook[NR_TP] = {
+ {
+ .probe = handle_switch_in,
+ .name = /* XXX: tracepoint name here */,
+ .registered = 0
+ },
+ {
+ .probe = handle_switch_out,
+ .name = /* XXX: tracepoint name here */,
+ .registered = 0
+ },
+ {
+ .probe = handle_wakeup,
+ .name = /* XXX: tracepoint name here */,
+ .registered = 0
+ },
+};
+
+static int start_wwnr(void)
+{
+ int retval;
+
+ da_monitor_init_wwnr();
+
+ retval = thh_hook_probes(tracepoints_to_hook, NR_TP);
+ if (retval)
+ goto out_err;
+
+ return 0;
+
+out_err:
+ return -EINVAL;
+}
+
+static void stop_wwnr(void)
+{
+ rv_wwnr.enabled = 0;
+ thh_unhook_probes(tracepoints_to_hook, NR_TP);
+ return;
+}
+
+/*
+ * 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 v2");
+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..4af1827d2f16
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM rv
+
+#if !defined(_WWNR_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _WWNR_TRACE_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(event_wwnr,
+
+ TP_PROTO(pid_t pid, char state, char event, char next_state, bool safe),
+
+ TP_ARGS(pid, state, event, next_state, safe),
+
+ TP_STRUCT__entry(
+ __field( pid_t, pid )
+ __field( char, state )
+ __field( char, event )
+ __field( char, next_state )
+ __field( bool, safe )
+ ),
+
+ TP_fast_assign(
+ __entry->pid = pid;
+ __entry->state = state;
+ __entry->event = event;
+ __entry->next_state = next_state;
+ __entry->safe = safe;
+ ),
+
+ TP_printk("%d: %s x %s -> %s %s",
+ __entry->pid,
+ model_get_state_name_wwnr(__entry->state),
+ model_get_event_name_wwnr(__entry->event),
+ model_get_state_name_wwnr(__entry->next_state),
+ __entry->safe ? "(safe)" : "")
+);
+
+TRACE_EVENT(error_wwnr,
+
+ TP_PROTO(pid_t pid, char state, char event),
+
+ TP_ARGS(pid, state, event),
+
+ TP_STRUCT__entry(
+ __field( pid_t, pid )
+ __field( char, state )
+ __field( char, event )
+ ),
+
+ TP_fast_assign(
+ __entry->pid = pid;
+ __entry->state = state;
+ __entry->event = event;
+ ),
+
+ TP_printk("%d event %s not expected in the state %s",
+ __entry->pid,
+ model_get_event_name_wwnr(__entry->event),
+ model_get_state_name_wwnr(__entry->state))
+);
+
+#endif /* _WWNR_H */
+
+/* This part ust be outside protection */
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE wwnr
+#include <trace/define_trace.h>
--
2.26.2
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