linux-kernel - Re: [PATCH v8 3/5] selftests/ftrace: Add clear_dynamic

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Date:   Fri, 20 Aug 2021 09:13:25 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     linux-kernel@...r.kernel.org, linux-trace-devel@...r.kernel.org,
        Ingo Molnar <mingo@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        "Tzvetomir Stoyanov" <tz.stoyanov@...il.com>,
        Tom Zanussi <zanussi@...nel.org>,
        Shuah Khan <shuah@...nel.org>,
        Shuah Khan <skhan@...uxfoundation.org>,
        linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v8 3/5] selftests/ftrace: Add clear_dynamic_events() to
 test cases

On Thu, 19 Aug 2021 11:26:07 -0400
Steven Rostedt <rostedt@...dmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@...dmis.org>
> 
> Add a function to remove all dynamic events from the tracing directory. It
> requires a loop as some of the dynamic events may depend on others being
> removed first. Also add a safety that prevents it from looping infinitely
> due to a bug where an event never gets removed.
> 
> Link: https://lkml.kernel.org/r/20210819041842.696873153@goodmis.org
> 

Thank you for adding this useful function!

Acked-by: Masami Hiramatsu <mhiramat@...nel.org>


> Cc: Shuah Khan <shuah@...nel.org>
> Cc: Shuah Khan <skhan@...uxfoundation.org>
> Cc: linux-kselftest@...r.kernel.org
> Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
> ---
>  .../testing/selftests/ftrace/test.d/functions | 22 +++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> index a6fac927ee82..f68d336b961b 100644
> --- a/tools/testing/selftests/ftrace/test.d/functions
> +++ b/tools/testing/selftests/ftrace/test.d/functions
> @@ -83,6 +83,27 @@ clear_synthetic_events() { # reset all current synthetic events
>      done
>  }
>  
> +clear_dynamic_events() { # reset all current dynamic events
> +    again=1
> +    stop=1
> +    # loop mulitple times as some events require other to be removed first
> +    while [ $again -eq 1 ]; do
> +	stop=$((stop+1))
> +	# Prevent infinite loops
> +	if [ $stop -gt 10 ]; then
> +	    break;
> +	fi
> +	again=2
> +	grep -v '^#' dynamic_events|
> +	while read line; do
> +	    del=`echo $line | sed -e 's/^.\([^ ]*\).*/-\1/'`
> +	    if ! echo "$del" >> dynamic_events; then
> +		again=1
> +	    fi
> +	done
> +    done
> +}
> +
>  initialize_ftrace() { # Reset ftrace to initial-state
>  # As the initial state, ftrace will be set to nop tracer,
>  # no events, no triggers, no filters, no function filters,
> @@ -93,6 +114,7 @@ initialize_ftrace() { # Reset ftrace to initial-state
>      reset_events_filter
>      reset_ftrace_filter
>      disable_events
> +    clear_dynamic_events
>      [ -f set_event_pid ] && echo > set_event_pid
>      [ -f set_ftrace_pid ] && echo > set_ftrace_pid
>      [ -f set_ftrace_notrace ] && echo > set_ftrace_notrace
> -- 
> 2.30.2


-- 
Masami Hiramatsu <mhiramat@...nel.org>