On Thu, Feb 06, 2025 at 02:54:15AM -0800, Kumar Kartikeya Dwivedi wrote: > @@ -68,6 +71,44 @@ > > #include "mcs_spinlock.h" > > +struct rqspinlock_timeout { > + u64 timeout_end; > + u64 duration; > + u16 spin; > +}; > + > +static noinline int check_timeout(struct rqspinlock_timeout *ts) > +{ > + u64 time = ktime_get_mono_fast_ns(); This is only sane if you have a TSC clocksource. If you ever manage to hit the HPET fallback, you're *really* sad. > + > + if (!ts->timeout_end) { > + ts->timeout_end = time + ts->duration; > + return 0; > + } > + > + if (time > ts->timeout_end) > + return -ETIMEDOUT; > + > + return 0; > +} > + > +#define RES_CHECK_TIMEOUT(ts, ret) \ > + ({ \ > + if (!(ts).spin++) \ > + (ret) = check_timeout(&(ts)); \ > + (ret); \ > + })