qspinlock: Diagnostics for excessive lock-drop wait loop time
We see systems stuck in the queued_spin_lock_slowpath() loop that waits
for the lock to become unlocked in the case where the current CPU has
set pending state. Therefore, this not-for-mainline commit gives a warning
that includes the lock word state if the loop has been spinning for more
than 10 seconds. It also adds a WARN_ON_ONCE() that complains if the
lock is not in pending state.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
1 file changed
