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Minor tracing fixes:

Browse Source 
- Fix unregistering the same event twice a the user could disable
    the event osnoise will disable on unregistering.
 
  - Inform RCU of a quiescent state in the osnoise testing thread.
 
  - Fix some kerneldoc comments.
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Merge tag 'trace-v5.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Minor tracing fixes:

   - Fix unregistering the same event twice. A user could disable the
     same event that osnoise will disable on unregistering.

   - Inform RCU of a quiescent state in the osnoise testing thread.

   - Fix some kerneldoc comments"

* tag 'trace-v5.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix some W=1 warnings in kernel doc comments
  tracing/osnoise: Force quiescent states while tracing
  tracing/osnoise: Do not unregister events twice
This commit is contained in:
Linus Torvalds 2022-03-10 17:23:08 -08:00
commit dda64ead7e
2 changed files with 33 additions and 2 deletions
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4
kernel/trace/ftrace.c
View File

@ -7790,7 +7790,7 @@ int ftrace_is_dead(void)
/**
* register_ftrace_function - register a function for profiling
* @ops - ops structure that holds the function for profiling.
* @ops: ops structure that holds the function for profiling.
*
* Register a function to be called by all functions in the
* kernel.
@ -7817,7 +7817,7 @@ EXPORT_SYMBOL_GPL(register_ftrace_function);
/**
* unregister_ftrace_function - unregister a function for profiling.
* @ops - ops structure that holds the function to unregister
* @ops: ops structure that holds the function to unregister
*
* Unregister a function that was added to be called by ftrace profiling.
*/

31
kernel/trace/trace_osnoise.c
View File

@ -1386,6 +1386,26 @@ static int run_osnoise(void)
osnoise_stop_tracing();
}
/*
* In some cases, notably when running on a nohz_full CPU with
* a stopped tick PREEMPT_RCU has no way to account for QSs.
* This will eventually cause unwarranted noise as PREEMPT_RCU
* will force preemption as the means of ending the current
* grace period. We avoid this problem by calling
* rcu_momentary_dyntick_idle(), which performs a zero duration
* EQS allowing PREEMPT_RCU to end the current grace period.
* This call shouldn't be wrapped inside an RCU critical
* section.
*
* Note that in non PREEMPT_RCU kernels QSs are handled through
* cond_resched()
*/
if (IS_ENABLED(CONFIG_PREEMPT_RCU)) {
local_irq_disable();
rcu_momentary_dyntick_idle();
local_irq_enable();
}
/*
* For the non-preemptive kernel config: let threads runs, if
* they so wish.
@ -2200,6 +2220,17 @@ static void osnoise_workload_stop(void)
if (osnoise_has_registered_instances())
return;
/*
* If callbacks were already disabled in a previous stop
* call, there is no need to disable then again.
*
* For instance, this happens when tracing is stopped via:
* echo 0 > tracing_on
* echo nop > current_tracer.
*/
if (!trace_osnoise_callback_enabled)
return;
trace_osnoise_callback_enabled = false;
/*
* Make sure that ftrace_nmi_enter/exit() see