From ba040653b48d32afa8b6c3331eae97c6bbb66f03 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 22 May 2015 11:36:13 +0200 Subject: [PATCH] perf/x86/intel: Simplify put_exclusive_constraints() 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) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event_intel.c | 29 +++++++++++++------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index f3201439031d..74f19d9268bb 100644 --- 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(struct cpu_hw_events *cpuc, 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(struct cpu_hw_events *cpuc, 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(struct cpu_hw_events *cpuc, } /* - * 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 -- 2.30.2