Re: [PATCH 11/12] locking/mutex: Revive fast functions for CONFIG_LOCK_TRACEPOINTS

[Peter Zijlstra]

On Tue, Feb 08, 2022 at 10:42:07AM -0800, Namhyung Kim wrote:
> I'm not entirely sure why it removed the fast versions when lockdep is
> on.  It seems easy to add the required annotation when the fast
> version is succeeded as far as the tracpoints are concerned.

IIRC it was something like, lockdep depends on MUTEX_DEBUG and that in
turn relied on not having the fast path enabled. MUTEX_DEBUG used to
always take the wait_lock to ensure the debug state is consistent with
the lock state.