Re: [RFC PATCH 1/2] locking: add mutex_lock_nospin()

[Yafang Shao]

On Thu, Mar 5, 2026 at 10:28 AM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> On Thu, 5 Mar 2026 10:17:09 +0800
> Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> > bpftrace is a widely used tool for online debugging and dynamic
> > tracing. However, sysadmins may unknowingly run multiple bpftrace
> > instances concurrently without realizing the potential impact on
> > system performance.
> >
> > If this is your answer, I believe we should clearly document the
> > following warning:
> >
> >   Warning: Do not read available_filter_functions concurrently, as
> > doing so can significantly degrade system performance and potentially
> > impact production workloads.
>
> Or update bpftrace to cache that file. It's only updated on module load
> and unload, which isn't done much. There's no reason it needs to
> constantly read that file if bpftrace is being used constantly.

Other tools may also read available_filter_functions, requiring each
one to be patched individually to avoid this flaw—a clearly
impractical solution.

-- 
Regards
Yafang