Don't bother with taking locks if we're not actually going to do anything. Also, drop the _irqsave(), this is very much only called from IRQ-disabled context.
Signed-off-by: Peter Zijlstra (Intel) <[email protected]> --- arch/x86/kernel/cpu/perf_event_intel.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -2130,7 +2130,6 @@ static void intel_put_excl_constraints(s struct intel_excl_cntrs *excl_cntrs = cpuc->excl_cntrs; int tid = cpuc->excl_thread_id; struct intel_excl_states *xl; - unsigned long flags = 0; /* keep compiler happy */ /* * nothing needed if in group validation mode @@ -2141,7 +2140,6 @@ static void intel_put_excl_constraints(s if (WARN_ON_ONCE(!excl_cntrs)) return; - xl = &excl_cntrs->states[tid]; if (hwc->flags & PERF_X86_EVENT_EXCL_ACCT) { hwc->flags &= ~PERF_X86_EVENT_EXCL_ACCT; if (!--cpuc->n_excl) @@ -2149,22 +2147,25 @@ static void intel_put_excl_constraints(s } /* - * put_constraint may be called from x86_schedule_events() - * which already has the lock held so here make locking - * conditional + * If event was actually assigned, then mark the counter state as + * unused now. */ - if (!xl->sched_started) - raw_spin_lock_irqsave(&excl_cntrs->lock, flags); + if (hwc->idx >= 0) { + xl = &excl_cntrs->states[tid]; + + /* + * put_constraint may be called from x86_schedule_events() + * which already has the lock held so here make locking + * conditional. + */ + if (!xl->sched_started) + raw_spin_lock(&excl_cntrs->lock); - /* - * if event was actually assigned, then mark the - * counter state as unused now - */ - if (hwc->idx >= 0) xl->state[hwc->idx] = INTEL_EXCL_UNUSED; - if (!xl->sched_started) - raw_spin_unlock_irqrestore(&excl_cntrs->lock, flags); + if (!xl->sched_started) + raw_spin_unlock(&excl_cntrs->lock); + } } static void -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
