diff options
author | Steven Rostedt <rostedt@goodmis.org> | 2014-10-08 13:52:16 -0400 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2014-10-09 11:15:08 -0400 |
commit | addff1feb02b03cb766b9a611c6b2cebf29bc285 (patch) | |
tree | faf54b05294f2feac72d62ebafb2fcbe959185e0 /kernel/trace/trace_selftest.c | |
parent | fe0e01c77dd9f7a60916aec2149d8a1182baf63c (diff) |
tracing: Clean up scheduling in trace_wakeup_test_thread()
Peter's new debugging tool triggers when tasks exit with !TASK_RUNNING.
The code in trace_wakeup_test_thread() also has a single schedule() call
that should be encompassed by a loop.
This cleans up the code a little to make it a bit more robust and
also makes the return exit properly with TASK_RUNNING.
Link: http://lkml.kernel.org/p/20141008135216.76142204@gandalf.local.home
Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infreadead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_selftest.c')
-rw-r--r-- | kernel/trace/trace_selftest.c | 47 |
1 files changed, 30 insertions, 17 deletions
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 5ef60499dc8e..593f52b73551 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -1025,6 +1025,12 @@ trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr) #endif #ifdef CONFIG_SCHED_TRACER + +struct wakeup_test_data { + struct completion is_ready; + int go; +}; + static int trace_wakeup_test_thread(void *data) { /* Make this a -deadline thread */ @@ -1034,51 +1040,56 @@ static int trace_wakeup_test_thread(void *data) .sched_deadline = 10000000ULL, .sched_period = 10000000ULL }; - struct completion *x = data; + struct wakeup_test_data *x = data; sched_setattr(current, &attr); /* Make it know we have a new prio */ - complete(x); + complete(&x->is_ready); /* now go to sleep and let the test wake us up */ set_current_state(TASK_INTERRUPTIBLE); - schedule(); + while (!x->go) { + schedule(); + set_current_state(TASK_INTERRUPTIBLE); + } - complete(x); + complete(&x->is_ready); + + set_current_state(TASK_INTERRUPTIBLE); /* we are awake, now wait to disappear */ while (!kthread_should_stop()) { - /* - * This will likely be the system top priority - * task, do short sleeps to let others run. - */ - msleep(100); + schedule(); + set_current_state(TASK_INTERRUPTIBLE); } + __set_current_state(TASK_RUNNING); + return 0; } - int trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) { unsigned long save_max = tr->max_latency; struct task_struct *p; - struct completion is_ready; + struct wakeup_test_data data; unsigned long count; int ret; - init_completion(&is_ready); + memset(&data, 0, sizeof(data)); + + init_completion(&data.is_ready); /* create a -deadline thread */ - p = kthread_run(trace_wakeup_test_thread, &is_ready, "ftrace-test"); + p = kthread_run(trace_wakeup_test_thread, &data, "ftrace-test"); if (IS_ERR(p)) { printk(KERN_CONT "Failed to create ftrace wakeup test thread "); return -1; } /* make sure the thread is running at -deadline policy */ - wait_for_completion(&is_ready); + wait_for_completion(&data.is_ready); /* start the tracing */ ret = tracer_init(trace, tr); @@ -1099,18 +1110,20 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) msleep(100); } - init_completion(&is_ready); + init_completion(&data.is_ready); + + data.go = 1; + /* memory barrier is in the wake_up_process() */ wake_up_process(p); /* Wait for the task to wake up */ - wait_for_completion(&is_ready); + wait_for_completion(&data.is_ready); /* stop the tracing. */ tracing_stop(); /* check both trace buffers */ ret = trace_test_buffer(&tr->trace_buffer, NULL); - printk("ret = %d\n", ret); if (!ret) ret = trace_test_buffer(&tr->max_buffer, &count); |