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tracing/osnoise: Do not follow tracing_cpumask 

In preparation to support multiple instances, decouple the
osnoise/timelat workload from instance-specific tracing_cpumask.

Different instances can have conflicting cpumasks, making osnoise
workload management needlessly complex. Osnoise already has its
global cpumask.

I also thought about using the first instance mask, but the
"first" instance could be removed before the others.

This also fixes the problem that changing the tracing_mask was not
re-starting the trace.

Link: https://lkml.kernel.org/r/169a71bcc919ce3ab53ae6f9ca5cde57fffaf9c6.1635702894.git.bristot@kernel.org

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@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 (VMware) <rostedt@goodmis.org>
This commit is contained in:
Daniel Bristot de Oliveira 2021-10-31 19:04:56 +01:00 committed by Steven Rostedt (VMware)
parent feea69ec12
commit 66df27f19f
1 changed files with 6 additions and 18 deletions
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24
kernel/trace/trace_osnoise.c
View File

@ -1554,13 +1554,9 @@ static int start_per_cpu_kthreads(struct trace_array *tr)
cpus_read_lock();
/*
* Run only on CPUs in which trace and osnoise are allowed to run.
* Run only on online CPUs in which osnoise is allowed to run.
*/
cpumask_and(current_mask, tr->tracing_cpumask, &osnoise_cpumask);
/*
* And the CPU is online.
*/
cpumask_and(current_mask, cpu_online_mask, current_mask);
cpumask_and(current_mask, cpu_online_mask, &osnoise_cpumask);
for_each_possible_cpu(cpu)
per_cpu(per_cpu_osnoise_var, cpu).kthread = NULL;
@ -1581,10 +1577,8 @@ static int start_per_cpu_kthreads(struct trace_array *tr)
#ifdef CONFIG_HOTPLUG_CPU
static void osnoise_hotplug_workfn(struct work_struct *dummy)
{
struct trace_array *tr = osnoise_trace;
unsigned int cpu = smp_processor_id();
mutex_lock(&trace_types_lock);
if (!osnoise_busy)
@ -1596,9 +1590,6 @@ static void osnoise_hotplug_workfn(struct work_struct *dummy)
if (!cpumask_test_cpu(cpu, &osnoise_cpumask))
goto out_unlock;
if (!cpumask_test_cpu(cpu, tr->tracing_cpumask))
goto out_unlock;
start_kthread(cpu);
out_unlock:
@ -1701,13 +1692,10 @@ static void osnoise_tracer_stop(struct trace_array *tr);
* interface to the osnoise trace. By default, it lists all CPUs,
* in this way, allowing osnoise threads to run on any online CPU
* of the system. It serves to restrict the execution of osnoise to the
* set of CPUs writing via this interface. Note that osnoise also
* respects the "tracing_cpumask." Hence, osnoise threads will run only
* on the set of CPUs allowed here AND on "tracing_cpumask." Why not
* have just "tracing_cpumask?" Because the user might be interested
* in tracing what is running on other CPUs. For instance, one might
* run osnoise in one HT CPU while observing what is running on the
* sibling HT CPU.
* set of CPUs writing via this interface. Why not use "tracing_cpumask"?
* Because the user might be interested in tracing what is running on
* other CPUs. For instance, one might run osnoise in one HT CPU
* while observing what is running on the sibling HT CPU.
*/
static ssize_t
osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,