Re: [PATCH] ftrace: Prevent RCU stall on PREEMPT_VOLUNTARY kernels

From: Guilherme G. Piccoli
Date: Tue Dec 13 2022 - 17:05:07 EST




On 16/11/2022 03:36, Masami Hiramatsu (Google) wrote:
> On Tue, 15 Nov 2022 17:48:47 -0300
> "Guilherme G. Piccoli" <gpiccoli@xxxxxxxxxx> wrote:
>
>> The function match_records() may take a while due to a large
>> number of string comparisons, so when in PREEMPT_VOLUNTARY
>> kernels we could face RCU stalls due to that.
>>
>> Add a cond_resched() to prevent that.
>>
>> Suggested-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxx> # from RCU CPU stall warning perspective
>> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
>> Cc: Mark Rutland <mark.rutland@xxxxxxx>
>> Signed-off-by: Guilherme G. Piccoli <gpiccoli@xxxxxxxxxx>
>
> This looks good to me.
>
> Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
>
> Thanks!
>

Hi Steve, sorry to annoy, just a regular ping to see if we can get this
into 6.2 (if too late, not a huge deal).

Thanks,


Guilherme