1 files changed, 174 insertions, 21 deletions

diff --git a/arch/x86/kernel/cpu/perf_event_intel_cqm.c b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
index b5d9d74..8003d87 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
@@ -182,23 +182,124 @@ fail:
 
 /*
  * Determine if @a and @b measure the same set of tasks.
+ *
+ * If @a and @b measure the same set of tasks then we want to share a
+ * single RMID.
  */
 static bool __match_event(struct perf_event *a, struct perf_event *b)
 {
+	/* Per-cpu and task events don't mix */
 	if ((a->attach_state & PERF_ATTACH_TASK) !=
 	    (b->attach_state & PERF_ATTACH_TASK))
 		return false;
 
-	/* not task */
+#ifdef CONFIG_CGROUP_PERF
+	if (a->cgrp != b->cgrp)
+		return false;
+#endif
+
+	/* If not task event, we're machine wide */
+	if (!(b->attach_state & PERF_ATTACH_TASK))
+		return true;
+
+	/*
+	 * Events that target same task are placed into the same cache group.
+	 */
+	if (a->hw.cqm_target == b->hw.cqm_target)
+		return true;
+
+	/*
+	 * Are we an inherited event?
+	 */
+	if (b->parent == a)
+		return true;
+
+	return false;
+}
+
+#ifdef CONFIG_CGROUP_PERF
+static inline struct perf_cgroup *event_to_cgroup(struct perf_event *event)
+{
+	if (event->attach_state & PERF_ATTACH_TASK)
+		return perf_cgroup_from_task(event->hw.cqm_target);
 
-	return true; /* if not task, we're machine wide */
+	return event->cgrp;
 }
+#endif
 
 /*
  * Determine if @a's tasks intersect with @b's tasks
+ *
+ * There are combinations of events that we explicitly prohibit,
+ *
+ *		   PROHIBITS
+ *     system-wide    -> 	cgroup and task
+ *     cgroup 	      ->	system-wide
+ *     		      ->	task in cgroup
+ *     task 	      -> 	system-wide
+ *     		      ->	task in cgroup
+ *
+ * Call this function before allocating an RMID.
  */
 static bool __conflict_event(struct perf_event *a, struct perf_event *b)
 {
+#ifdef CONFIG_CGROUP_PERF
+	/*
+	 * We can have any number of cgroups but only one system-wide
+	 * event at a time.
+	 */
+	if (a->cgrp && b->cgrp) {
+		struct perf_cgroup *ac = a->cgrp;
+		struct perf_cgroup *bc = b->cgrp;
+
+		/*
+		 * This condition should have been caught in
+		 * __match_event() and we should be sharing an RMID.
+		 */
+		WARN_ON_ONCE(ac == bc);
+
+		if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) ||
+		    cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup))
+			return true;
+
+		return false;
+	}
+
+	if (a->cgrp || b->cgrp) {
+		struct perf_cgroup *ac, *bc;
+
+		/*
+		 * cgroup and system-wide events are mutually exclusive
+		 */
+		if ((a->cgrp && !(b->attach_state & PERF_ATTACH_TASK)) ||
+		    (b->cgrp && !(a->attach_state & PERF_ATTACH_TASK)))
+			return true;
+
+		/*
+		 * Ensure neither event is part of the other's cgroup
+		 */
+		ac = event_to_cgroup(a);
+		bc = event_to_cgroup(b);
+		if (ac == bc)
+			return true;
+
+		/*
+		 * Must have cgroup and non-intersecting task events.
+		 */
+		if (!ac || !bc)
+			return false;
+
+		/*
+		 * We have cgroup and task events, and the task belongs
+		 * to a cgroup. Check for for overlap.
+		 */
+		if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) ||
+		    cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup))
+			return true;
+
+		return false;
+	}
+#endif
 	/*
 	 * If one of them is not a task, same story as above with cgroups.
 	 */
@@ -245,9 +346,16 @@ static int intel_cqm_setup_event(struct perf_event *event,
 
 static void intel_cqm_event_read(struct perf_event *event)
 {
-	unsigned long rmid = event->hw.cqm_rmid;
+	unsigned long rmid;
 	u64 val;
 
+	/*
+	 * Task events are handled by intel_cqm_event_count().
+	 */
+	if (event->cpu == -1)
+		return;
+
+	rmid = event->hw.cqm_rmid;
 	val = __rmid_read(rmid);
 
 	/*
@@ -259,6 +367,63 @@ static void intel_cqm_event_read(struct perf_event *event)
 	local64_set(&event->count, val);
 }
 
+struct rmid_read {
+	unsigned int rmid;
+	atomic64_t value;
+};
+
+static void __intel_cqm_event_count(void *info)
+{
+	struct rmid_read *rr = info;
+	u64 val;
+
+	val = __rmid_read(rr->rmid);
+
+	if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
+		return;
+
+	atomic64_add(val, &rr->value);
+}
+
+static inline bool cqm_group_leader(struct perf_event *event)
+{
+	return !list_empty(&event->hw.cqm_groups_entry);
+}
+
+static u64 intel_cqm_event_count(struct perf_event *event)
+{
+	struct rmid_read rr = {
+		.rmid = event->hw.cqm_rmid,
+		.value = ATOMIC64_INIT(0),
+	};
+
+	/*
+	 * We only need to worry about task events. System-wide events
+	 * are handled like usual, i.e. entirely with
+	 * intel_cqm_event_read().
+	 */
+	if (event->cpu != -1)
+		return __perf_event_count(event);
+
+	/*
+	 * Only the group leader gets to report values. This stops us
+	 * reporting duplicate values to userspace, and gives us a clear
+	 * rule for which task gets to report the values.
+	 *
+	 * Note that it is impossible to attribute these values to
+	 * specific packages - we forfeit that ability when we create
+	 * task events.
+	 */
+	if (!cqm_group_leader(event))
+		return 0;
+
+	on_each_cpu_mask(&cqm_cpumask, __intel_cqm_event_count, &rr, 1);
+
+	local64_set(&event->count, atomic64_read(&rr.value));
+
+	return __perf_event_count(event);
+}
+
 static void intel_cqm_event_start(struct perf_event *event, int mode)
 {
 	struct intel_cqm_state *state = this_cpu_ptr(&cqm_state);
@@ -344,7 +509,7 @@ static void intel_cqm_event_destroy(struct perf_event *event)
 	/*
 	 * And we're the group leader..
 	 */
-	if (!list_empty(&event->hw.cqm_groups_entry)) {
+	if (cqm_group_leader(event)) {
 		/*
 		 * If there was a group_other, make that leader, otherwise
 		 * destroy the group and return the RMID.
@@ -365,17 +530,6 @@ static void intel_cqm_event_destroy(struct perf_event *event)
 
 static struct pmu intel_cqm_pmu;
 
-/*
- * XXX there's a bit of a problem in that we cannot simply do the one
- * event per node as one would want, since that one event would one get
- * scheduled on the one cpu. But we want to 'schedule' the RMID on all
- * CPUs.
- *
- * This means we want events for each CPU, however, that generates a lot
- * of duplicate values out to userspace -- this is not to be helped
- * unless we want to change the core code in some way. Fore more info,
- * see intel_cqm_event_read().
- */
 static int intel_cqm_event_init(struct perf_event *event)
 {
 	struct perf_event *group = NULL;
@@ -387,9 +541,6 @@ static int intel_cqm_event_init(struct perf_event *event)
 	if (event->attr.config & ~QOS_EVENT_MASK)
 		return -EINVAL;
 
-	if (event->cpu == -1)
-		return -EINVAL;
-
 	/* unsupported modes and filters */
 	if (event->attr.exclude_user   ||
 	    event->attr.exclude_kernel ||
@@ -407,7 +558,8 @@ static int intel_cqm_event_init(struct perf_event *event)
 
 	mutex_lock(&cache_mutex);
 
-	err = intel_cqm_setup_event(event, &group); /* will also set rmid */
+	/* Will also set rmid */
+	err = intel_cqm_setup_event(event, &group);
 	if (err)
 		goto out;
 
@@ -470,6 +622,7 @@ static struct pmu intel_cqm_pmu = {
 	.start		= intel_cqm_event_start,
 	.stop		= intel_cqm_event_stop,
 	.read		= intel_cqm_event_read,
+	.count		= intel_cqm_event_count,
 };
 
 static inline void cqm_pick_event_reader(int cpu)
@@ -599,8 +752,8 @@ static int __init intel_cqm_init(void)
 
 	__perf_cpu_notifier(intel_cqm_cpu_notifier);
 
-	ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm", -1);
-
+	ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm",
+				PERF_TYPE_INTEL_CQM);
 	if (ret)
 		pr_err("Intel CQM perf registration failed: %d\n", ret);
 	else