Why are there "<IRQ>" and "</IRQ>" in the call trace section? What does them imply?

Why are there "<IRQ>" and "</IRQ>" in the call trace section? What does them imply?

[孙世龙 sunshilong]

Hi, list

As the subject, here is the related log:
[72873.713472] Call Trace:
[72873.713473]  <IRQ>
[72873.713474]  switch_mm_irqs_off+0x31b/0x4e0
[72873.713475]  xnarch_switch_to+0x2f/0x80
[72873.713476]  ___xnsched_run.part.74+0x154/0x480
[72873.713476]  ___xnsched_run+0x35/0x50
[72873.713477]  xnintr_irq_handler+0x346/0x4c0
[72873.713478]  ? xnintr_core_clock_handler+0x1b6/0x360
[72873.713479]  dispatch_irq_head+0x8e/0x110
[72873.713479]  ? xnintr_irq_handler+0x5/0x4c0
[72873.713481]  ? dispatch_irq_head+0x8e/0x110
[72873.713482]  __ipipe_dispatch_irq+0xd9/0x1c0
[72873.713483]  __ipipe_handle_irq+0x86/0x1e0
[72873.713483]  common_interrupt+0xf/0x2c
[72873.713484]  </IRQ>

Maybe, the later one(i.e. </IRQ>) implies there was an interrupt
request and the common_interuppt() function handler it.
Am I right?

But what about the former one(i.e. <IRQ>)?

Thank you for your attention to this matter.

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

Re: Why are there "<IRQ>" and "</IRQ>" in the call trace section? What does them imply?

[Valdis Klētnieks]

[-- Attachment #1.1: Type: text/plain, Size: 1265 bytes --]

On Fri, 10 Jul 2020 13:29:29 +0800, "e- d8 i> sunshilong" said:

> [72873.713473]  <IRQ>
> [72873.713474]  switch_mm_irqs_off+0x31b/0x4e0
> [72873.713475]  xnarch_switch_to+0x2f/0x80
> [72873.713476]  ___xnsched_run.part.74+0x154/0x480
> [72873.713476]  ___xnsched_run+0x35/0x50
> [72873.713477]  xnintr_irq_handler+0x346/0x4c0
> [72873.713478]  ? xnintr_core_clock_handler+0x1b6/0x360
> [72873.713479]  dispatch_irq_head+0x8e/0x110
> [72873.713479]  ? xnintr_irq_handler+0x5/0x4c0
> [72873.713481]  ? dispatch_irq_head+0x8e/0x110
> [72873.713482]  __ipipe_dispatch_irq+0xd9/0x1c0
> [72873.713483]  __ipipe_handle_irq+0x86/0x1e0
> [72873.713483]  common_interrupt+0xf/0x2c
> [72873.713484]  </IRQ>
>
> Maybe, the later one(i.e. </IRQ>) implies there was an interrupt
> request and the common_interuppt() function handler it.

No.  It's possible for the kernel traceback to include some routines that
were in an IRQ, and some more that were outside IRQ context.  So you
can tell which are which, the stack dump is formatted as:

<IRQ>
function that was running when the trace was called for
the function that call it
another function back
(...)
interrupt_handler  of some sort
</IRQ>
function that was running when the interrupt hit
this caller
and its parent
etc



[-- Attachment #1.2: Type: application/pgp-signature, Size: 832 bytes --]

[-- Attachment #2: Type: text/plain, Size: 170 bytes --]

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

Re: Why are there "<IRQ>" and "</IRQ>" in the call trace section? What does them imply?

[CVS]

While i am not sure why this notation was chosen,
at least one precedent would be HTML
where an element is defined by
a starting tag named within angle-brackets
and the end of the element is defined by
a corresponding tag with the the same name prefixed with a "/"

https://en.wikipedia.org/wiki/HTML_element#Syntax

regards
CVS

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies