Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fixes from Ingo Molnar:
 "A bogus warning fix, a counter width handling fix affecting certain
  machines, plus a oneliner hw-enablement patch for Knights Mill CPUs"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Remove invalid warning from list_update_cgroup_even()t
  perf/x86: Fix full width counter, counter overflow
  perf/x86/intel: Enable C-state residency events for Knights Mill

Author: torvalds

arch/x86/events/core.c

@@ -69,7 +69,7 @@ u64 x86_perf_event_update(struct perf_event *event)
 	int shift = 64 - x86_pmu.cntval_bits;
 	u64 prev_raw_count, new_raw_count;
 	int idx = hwc->idx;
-	s64 delta;
+	u64 delta;
 
 	if (idx == INTEL_PMC_IDX_FIXED_BTS)
 		return 0;

arch/x86/events/intel/core.c

@@ -4034,7 +4034,7 @@ __init int intel_pmu_init(void)
 
 	/* Support full width counters using alternative MSR range */
 	if (x86_pmu.intel_cap.full_width_write) {
-		x86_pmu.max_period = x86_pmu.cntval_mask;
+		x86_pmu.max_period = x86_pmu.cntval_mask >> 1;
 		x86_pmu.perfctr = MSR_IA32_PMC0;
 		pr_cont("full-width counters, ");
 	}

arch/x86/events/intel/cstate.c

@@ -540,6 +540,7 @@ static const struct x86_cpu_id intel_cstates_match[] __initconst = {
 	X86_CSTATES_MODEL(INTEL_FAM6_SKYLAKE_DESKTOP, snb_cstates),
 
 	X86_CSTATES_MODEL(INTEL_FAM6_XEON_PHI_KNL, knl_cstates),
+	X86_CSTATES_MODEL(INTEL_FAM6_XEON_PHI_KNM, knl_cstates),
 	{ },
 };
 MODULE_DEVICE_TABLE(x86cpu, intel_cstates_match);

kernel/events/core.c

@@ -903,17 +903,14 @@ list_update_cgroup_event(struct perf_event *event,
 	 */
 	cpuctx = __get_cpu_context(ctx);
 
-	/* Only set/clear cpuctx->cgrp if current task uses event->cgrp. */
-	if (perf_cgroup_from_task(current, ctx) != event->cgrp) {
-		/*
-		 * We are removing the last cpu event in this context.
-		 * If that event is not active in this cpu, cpuctx->cgrp
-		 * should've been cleared by perf_cgroup_switch.
-		 */
-		WARN_ON_ONCE(!add && cpuctx->cgrp);
-		return;
-	}
-	cpuctx->cgrp = add ? event->cgrp : NULL;
+	/*
+	 * cpuctx->cgrp is NULL until a cgroup event is sched in or
+	 * ctx->nr_cgroup == 0 .
+	 */
+	if (add && perf_cgroup_from_task(current, ctx) == event->cgrp)
+		cpuctx->cgrp = event->cgrp;
+	else if (!add)
+		cpuctx->cgrp = NULL;
 }
 
 #else /* !CONFIG_CGROUP_PERF */