ccc319dcb4
Per task wakeup while not running (wwnr) monitor. 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. Link: https://lkml.kernel.org/r/473c0fc39967250fdebcff8b620311c11dccad30.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck <wim@linux-watchdog.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jonathan Corbet <corbet@lwn.net> 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: Tao Zhou <tao.zhou@linux.dev> Cc: Randy Dunlap <rdunlap@infradead.org> 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> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
88 lines
1.9 KiB
C
88 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/ftrace.h>
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#include <linux/tracepoint.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/rv.h>
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#include <rv/instrumentation.h>
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#include <rv/da_monitor.h>
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#define MODULE_NAME "wwnr"
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#include <trace/events/rv.h>
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#include <trace/events/sched.h>
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#include "wwnr.h"
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struct rv_monitor rv_wwnr;
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DECLARE_DA_MON_PER_TASK(wwnr, unsigned char);
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static void handle_switch(void *data, bool preempt, struct task_struct *p,
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struct task_struct *n, unsigned int prev_state)
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{
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/* start monitoring only after the first suspension */
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if (prev_state == TASK_INTERRUPTIBLE)
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da_handle_start_event_wwnr(p, switch_out_wwnr);
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else
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da_handle_event_wwnr(p, switch_out_wwnr);
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da_handle_event_wwnr(n, switch_in_wwnr);
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}
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static void handle_wakeup(void *data, struct task_struct *p)
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{
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da_handle_event_wwnr(p, wakeup_wwnr);
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}
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static int enable_wwnr(void)
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{
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int retval;
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retval = da_monitor_init_wwnr();
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if (retval)
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return retval;
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rv_attach_trace_probe("wwnr", sched_switch, handle_switch);
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rv_attach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
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return 0;
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}
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static void disable_wwnr(void)
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{
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rv_wwnr.enabled = 0;
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rv_detach_trace_probe("wwnr", sched_switch, handle_switch);
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rv_detach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
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da_monitor_destroy_wwnr();
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}
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struct rv_monitor rv_wwnr = {
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.name = "wwnr",
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.description = "wakeup while not running per-task testing model.",
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.enable = enable_wwnr,
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.disable = disable_wwnr,
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.reset = da_monitor_reset_all_wwnr,
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.enabled = 0,
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};
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static int register_wwnr(void)
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{
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rv_register_monitor(&rv_wwnr);
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return 0;
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}
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static void unregister_wwnr(void)
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{
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rv_unregister_monitor(&rv_wwnr);
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}
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module_init(register_wwnr);
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module_exit(unregister_wwnr);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Daniel Bristot de Oliveira <bristot@kernel.org>");
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MODULE_DESCRIPTION("wwnr: wakeup while not running monitor");
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