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    Subject[PATCH V4 10/20] rv/monitor: Add the wwnr monitor skeleton created by dot2k
    Date
    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@linux-watchdog.org>
    Cc: Guenter Roeck <linux@roeck-us.net>
    Cc: Jonathan Corbet <corbet@lwn.net>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Will Deacon <will@kernel.org>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Marco Elver <elver@google.com>
    Cc: Dmitry Vyukov <dvyukov@google.com>
    Cc: "Paul E. McKenney" <paulmck@kernel.org>
    Cc: Shuah Khan <skhan@linuxfoundation.org>
    Cc: Gabriele Paoloni <gpaoloni@redhat.com>
    Cc: Juri Lelli <juri.lelli@redhat.com>
    Cc: Clark Williams <williams@redhat.com>
    Cc: linux-doc@vger.kernel.org
    Cc: linux-kernel@vger.kernel.org
    Cc: linux-trace-devel@vger.kernel.org
    Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.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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