Re: [PATCH 2/2] trace/kprobe: Remove limit on kretprobe maxactive

From: Steven Rostedt
Date: Tue Jun 15 2021 - 21:03:56 EST


On Wed, 16 Jun 2021 09:46:22 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> To avoid such trouble, I had set the 4096 limitation for the maxactive
> parameter. Of course 4096 may not enough for some use-cases. I'm welcome
> to expand it (e.g. 32k, isn't it enough?), but removing the limitation
> may cause OOM trouble easily.

What if you just made the max as 10 * number of possible cpus, or 4096,
which ever is greater? Why would a user need more?

I'd still like to get a wrapper around function graph tracing so that
kretprobes could use it. I think that would get rid of the requirement
of maxactive, because isn't that just used to have a way to know the
original return value?

-- Steve