On Mon, 22 Jan 2024 10:57:00 -0500
Steven Rostedt [off-list ref] wrote:

On Mon, 22 Jan 2024 15:36:29 +0800
George Guo [off-list ref] wrote:

quoted

From: George Guo <redacted>

Add do_warn, warn_limit fields to the output of the
percpu_alloc_percpu_fail ftrace event.

This is required to percpu_alloc failed with no warning showing.  

You mean to state;

  In order to know why percpu_alloc failed but produces no warnings,
the do_warn and warn_limit should be traced to let the user know it
was rate-limited.

Or something like that?

Honestly, I don't think that the trace event is the proper place to do
that. The trace event just shows that it did fail. If you are
confused to why it doesn't print to dmesg, then you can simply add a
kprobe to see those values as well.

-- Steve

quoted

Signed-off-by: George Guo <redacted>
--- 

There are two reasons of percpu_alloc failed without warnings: 

1. do_warn is false
2. do_warn is true and warn_limit is reached the limit.

Showing do_warn and warn_limit makes things simple, maybe dont need
kprobe again.