Messages in this thread | | | Date | Fri, 27 Apr 2018 12:37:59 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH RFC] tracepoint: Introduce tracepoint callbacks executing with preempt on |
| |
On Fri, 27 Apr 2018 09:30:05 -0700 Joel Fernandes <joelaf@google.com> wrote:
> On Fri, Apr 27, 2018 at 7:47 AM, Steven Rostedt <rostedt@goodmis.org> wrote: > > On Fri, 27 Apr 2018 10:26:29 -0400 (EDT) > > Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote: > > > >> The general approach and the implementation look fine, except for > >> one small detail: I would be tempted to explicitly disable preemption > >> around the call to the tracepoint callback for the rcuidle variant, > >> unless we plan to audit every tracer right away to remove any assumption > >> that preemption is disabled in the callback implementation. > > > > I'm thinking that we do that audit. There shouldn't be many instances > > of it. I like the idea that a tracepoint callback gets called with > > preemption enabled. > > Here is the list of all callers of the _rcuidle :
I was thinking of auditing who registers callbacks to any tracepoints.
-- Steve
> > trace_clk_disable_complete_rcuidle > trace_clk_disable_rcuidle > trace_clk_enable_complete_rcuidle > trace_clk_enable_rcuidle > trace_console_rcuidle > trace_cpu_idle_rcuidle > trace_ipi_entry_rcuidle > trace_ipi_exit_rcuidle > trace_ipi_raise_rcuidle > trace_irq_disable_rcuidle > trace_irq_enable_rcuidle > trace_power_domain_target_rcuidle > trace_preempt_disable_rcuidle > trace_preempt_enable_rcuidle > trace_rpm_idle_rcuidle > trace_rpm_resume_rcuidle > trace_rpm_return_int_rcuidle > trace_rpm_suspend_rcuidle > trace_tlb_flush_rcuidle > > All of these are either called from irqs or preemption disabled > already. So I think it should be fine to keep preemption on. But I'm > Ok with disabling it before callback execution if we agree that we > want that. > > (and the ring buffer code is able to cope anyway Steven pointed). > > thanks, > > - Joel
| |