diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-10 17:23:08 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-10 17:23:08 -0800 |
| commit | dda64ead7e82caa47fafe0edc36067ee64df2203 (patch) | |
| tree | b3640f49cd50e129228332f61d6cbcae883318d6 /kernel | |
| parent | 186d32bbf034417b40e2b4e773eeb8ef106c16c1 (diff) | |
| parent | 78cbc6513217b00be6a9904415ef7ff3619eb035 (diff) | |
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
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/ftrace.c | 4 | ||||
| -rw-r--r-- | kernel/trace/trace_osnoise.c | 31 |
2 files changed, 33 insertions, 2 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a4b462b6f944..6105b7036482 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -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. */ diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index cfddb30e65ab..5e3c62a08fc0 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -1387,6 +1387,26 @@ static int run_osnoise(void) } /* + * 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 |