Messages in this thread | | | Date | Sat, 30 Sep 2017 05:08:17 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v6 2/2] tracing: Add support for preempt and irq enable/disable events |
| |
On Mon, 25 Sep 2017 17:23:00 -0700 Joel Fernandes <joelaf@google.com> wrote:
> The trace_hardirqs_off API can be called even when IRQs are already > off. This is unlike the trace_hardirqs_on which checks if IRQs are off > (atleast from some callsites), here are the definitions just for > reference [1]. I guess we could modify local_irq_disable and > local_irq_save to check what the HW flags was before calling > raw_local_irq_save and only then call trace_hardirqs_off if they were > indeed on and now being turned off, but that adds complexity to it - > also we have to then modify all the callsites from assembly code to > conditionally call trace_hardirqs_on/off :(. >
> [1] http://elixir.free-electrons.com/linux/latest/source/include/linux/irqflags.h#L89
Yeah, I think the issue for the recursion is basically this:
#define local_irq_restore(flags) \ do { \ if (raw_irqs_disabled_flags(flags)) { \ raw_local_irq_restore(flags); \ trace_hardirqs_off(); \ } else { \ trace_hardirqs_on(); \ raw_local_irq_restore(flags); \ } \ } while (0)
Peter,
Is there any place where we would call local_irq_restore() when interrupts are enabled?
-- Steve
| |