Re: [RFT PATCH 04/13] kprobes: Make optimizer delay to 1 second

[Steven Rostedt]

On Thu, 16 Jan 2020 23:44:52 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> Since the 5 jiffies delay for the optimizer is too
> short to wait for other probes, make it longer,
> like 1 second.

Hi Masami,

Can you explain more *why* 5 jiffies is too short.

Thanks!

-- Steve

> 
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> ---
>  kernel/kprobes.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 0dacdcecc90f..9c6e230852ad 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -469,7 +469,8 @@ static int kprobe_optimizer_queue_update;
>  
>  static void kprobe_optimizer(struct work_struct *work);
>  static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
> -#define OPTIMIZE_DELAY 5
> +/* Wait 1 second for starting optimization */
> +#define OPTIMIZE_DELAY HZ
>  
>  /*
>   * Optimize (replace a breakpoint with a jump) kprobes listed on