1 files changed, 70 insertions, 55 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 36babfd20648..cfc227ccfceb 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3,7 +3,7 @@
  *
  *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
  *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
- *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
  *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
  *
  * For licensing details see kernel-base/COPYING
@@ -435,7 +435,7 @@ static inline void update_cgrp_time_from_event(struct perf_event *event)
 	if (!is_cgroup_event(event))
 		return;
 
-	cgrp = perf_cgroup_from_task(current);
+	cgrp = perf_cgroup_from_task(current, event->ctx);
 	/*
 	 * Do not update time when cgroup is not active
 	 */
@@ -458,7 +458,7 @@ perf_cgroup_set_timestamp(struct task_struct *task,
 	if (!task || !ctx->nr_cgroups)
 		return;
 
-	cgrp = perf_cgroup_from_task(task);
+	cgrp = perf_cgroup_from_task(task, ctx);
 	info = this_cpu_ptr(cgrp->info);
 	info->timestamp = ctx->timestamp;
 }
@@ -489,7 +489,6 @@ static void perf_cgroup_switch(struct task_struct *task, int mode)
 	 * we reschedule only in the presence of cgroup
 	 * constrained events.
 	 */
-	rcu_read_lock();
 
 	list_for_each_entry_rcu(pmu, &pmus, entry) {
 		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
@@ -522,8 +521,10 @@ static void perf_cgroup_switch(struct task_struct *task, int mode)
 				 * set cgrp before ctxsw in to allow
 				 * event_filter_match() to not have to pass
 				 * task around
+				 * we pass the cpuctx->ctx to perf_cgroup_from_task()
+				 * because cgorup events are only per-cpu
 				 */
-				cpuctx->cgrp = perf_cgroup_from_task(task);
+				cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
 				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
 			}
 			perf_pmu_enable(cpuctx->ctx.pmu);
@@ -531,8 +532,6 @@ static void perf_cgroup_switch(struct task_struct *task, int mode)
 		}
 	}
 
-	rcu_read_unlock();
-
 	local_irq_restore(flags);
 }
 
@@ -542,17 +541,20 @@ static inline void perf_cgroup_sched_out(struct task_struct *task,
 	struct perf_cgroup *cgrp1;
 	struct perf_cgroup *cgrp2 = NULL;
 
+	rcu_read_lock();
 	/*
 	 * we come here when we know perf_cgroup_events > 0
+	 * we do not need to pass the ctx here because we know
+	 * we are holding the rcu lock
 	 */
-	cgrp1 = perf_cgroup_from_task(task);
+	cgrp1 = perf_cgroup_from_task(task, NULL);
 
 	/*
 	 * next is NULL when called from perf_event_enable_on_exec()
 	 * that will systematically cause a cgroup_switch()
 	 */
 	if (next)
-		cgrp2 = perf_cgroup_from_task(next);
+		cgrp2 = perf_cgroup_from_task(next, NULL);
 
 	/*
 	 * only schedule out current cgroup events if we know
@@ -561,6 +563,8 @@ static inline void perf_cgroup_sched_out(struct task_struct *task,
 	 */
 	if (cgrp1 != cgrp2)
 		perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
+
+	rcu_read_unlock();
 }
 
 static inline void perf_cgroup_sched_in(struct task_struct *prev,
@@ -569,13 +573,16 @@ static inline void perf_cgroup_sched_in(struct task_struct *prev,
 	struct perf_cgroup *cgrp1;
 	struct perf_cgroup *cgrp2 = NULL;
 
+	rcu_read_lock();
 	/*
 	 * we come here when we know perf_cgroup_events > 0
+	 * we do not need to pass the ctx here because we know
+	 * we are holding the rcu lock
 	 */
-	cgrp1 = perf_cgroup_from_task(task);
+	cgrp1 = perf_cgroup_from_task(task, NULL);
 
 	/* prev can never be NULL */
-	cgrp2 = perf_cgroup_from_task(prev);
+	cgrp2 = perf_cgroup_from_task(prev, NULL);
 
 	/*
 	 * only need to schedule in cgroup events if we are changing
@@ -584,6 +591,8 @@ static inline void perf_cgroup_sched_in(struct task_struct *prev,
 	 */
 	if (cgrp1 != cgrp2)
 		perf_cgroup_switch(task, PERF_CGROUP_SWIN);
+
+	rcu_read_unlock();
 }
 
 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
@@ -3145,15 +3154,16 @@ static int event_enable_on_exec(struct perf_event *event,
  * Enable all of a task's events that have been marked enable-on-exec.
  * This expects task == current.
  */
-static void perf_event_enable_on_exec(struct perf_event_context *ctx)
+static void perf_event_enable_on_exec(int ctxn)
 {
-	struct perf_event_context *clone_ctx = NULL;
+	struct perf_event_context *ctx, *clone_ctx = NULL;
 	struct perf_event *event;
 	unsigned long flags;
 	int enabled = 0;
 	int ret;
 
 	local_irq_save(flags);
+	ctx = current->perf_event_ctxp[ctxn];
 	if (!ctx || !ctx->nr_events)
 		goto out;
 
@@ -3196,17 +3206,11 @@ out:
 
 void perf_event_exec(void)
 {
-	struct perf_event_context *ctx;
 	int ctxn;
 
 	rcu_read_lock();
-	for_each_task_context_nr(ctxn) {
-		ctx = current->perf_event_ctxp[ctxn];
-		if (!ctx)
-			continue;
-
-		perf_event_enable_on_exec(ctx);
-	}
+	for_each_task_context_nr(ctxn)
+		perf_event_enable_on_exec(ctxn);
 	rcu_read_unlock();
 }
 
@@ -4216,7 +4220,14 @@ retry:
 		goto retry;
 	}
 
-	__perf_event_period(&pe);
+	if (event->attr.freq) {
+		event->attr.sample_freq = value;
+	} else {
+		event->attr.sample_period = value;
+		event->hw.sample_period = value;
+	}
+
+	local64_set(&event->hw.period_left, 0);
 	raw_spin_unlock_irq(&ctx->lock);
 
 	return 0;
@@ -5667,6 +5678,17 @@ perf_event_aux_ctx(struct perf_event_context *ctx,
 }
 
 static void
+perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
+			struct perf_event_context *task_ctx)
+{
+	rcu_read_lock();
+	preempt_disable();
+	perf_event_aux_ctx(task_ctx, output, data);
+	preempt_enable();
+	rcu_read_unlock();
+}
+
+static void
 perf_event_aux(perf_event_aux_output_cb output, void *data,
 	       struct perf_event_context *task_ctx)
 {
@@ -5675,14 +5697,23 @@ perf_event_aux(perf_event_aux_output_cb output, void *data,
 	struct pmu *pmu;
 	int ctxn;
 
+	/*
+	 * If we have task_ctx != NULL we only notify
+	 * the task context itself. The task_ctx is set
+	 * only for EXIT events before releasing task
+	 * context.
+	 */
+	if (task_ctx) {
+		perf_event_aux_task_ctx(output, data, task_ctx);
+		return;
+	}
+
 	rcu_read_lock();
 	list_for_each_entry_rcu(pmu, &pmus, entry) {
 		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
 		if (cpuctx->unique_pmu != pmu)
 			goto next;
 		perf_event_aux_ctx(&cpuctx->ctx, output, data);
-		if (task_ctx)
-			goto next;
 		ctxn = pmu->task_ctx_nr;
 		if (ctxn < 0)
 			goto next;
@@ -5692,12 +5723,6 @@ perf_event_aux(perf_event_aux_output_cb output, void *data,
 next:
 		put_cpu_ptr(pmu->pmu_cpu_context);
 	}
-
-	if (task_ctx) {
-		preempt_disable();
-		perf_event_aux_ctx(task_ctx, output, data);
-		preempt_enable();
-	}
 	rcu_read_unlock();
 }
 
@@ -6463,9 +6488,6 @@ struct swevent_htable {
 
 	/* Recursion avoidance in each contexts */
 	int				recursion[PERF_NR_CONTEXTS];
-
-	/* Keeps track of cpu being initialized/exited */
-	bool				online;
 };
 
 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
@@ -6723,14 +6745,8 @@ static int perf_swevent_add(struct perf_event *event, int flags)
 	hwc->state = !(flags & PERF_EF_START);
 
 	head = find_swevent_head(swhash, event);
-	if (!head) {
-		/*
-		 * We can race with cpu hotplug code. Do not
-		 * WARN if the cpu just got unplugged.
-		 */
-		WARN_ON_ONCE(swhash->online);
+	if (WARN_ON_ONCE(!head))
 		return -EINVAL;
-	}
 
 	hlist_add_head_rcu(&event->hlist_entry, head);
 	perf_event_update_userpage(event);
@@ -6798,7 +6814,6 @@ static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
 	int err = 0;
 
 	mutex_lock(&swhash->hlist_mutex);
-
 	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
 		struct swevent_hlist *hlist;
 
@@ -8787,10 +8802,8 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
 	struct perf_event_context *child_ctx, *clone_ctx = NULL;
 	unsigned long flags;
 
-	if (likely(!child->perf_event_ctxp[ctxn])) {
-		perf_event_task(child, NULL, 0);
+	if (likely(!child->perf_event_ctxp[ctxn]))
 		return;
-	}
 
 	local_irq_save(flags);
 	/*
@@ -8874,6 +8887,14 @@ void perf_event_exit_task(struct task_struct *child)
 
 	for_each_task_context_nr(ctxn)
 		perf_event_exit_task_context(child, ctxn);
+
+	/*
+	 * The perf_event_exit_task_context calls perf_event_task
+	 * with child's task_ctx, which generates EXIT events for
+	 * child contexts and sets child->perf_event_ctxp[] to NULL.
+	 * At this point we need to send EXIT events to cpu contexts.
+	 */
+	perf_event_task(child, NULL, 0);
 }
 
 static void perf_free_event(struct perf_event *event,
@@ -9255,7 +9276,6 @@ static void perf_event_init_cpu(int cpu)
 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
 
 	mutex_lock(&swhash->hlist_mutex);
-	swhash->online = true;
 	if (swhash->hlist_refcount > 0) {
 		struct swevent_hlist *hlist;
 
@@ -9297,14 +9317,7 @@ static void perf_event_exit_cpu_context(int cpu)
 
 static void perf_event_exit_cpu(int cpu)
 {
-	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
-
 	perf_event_exit_cpu_context(cpu);
-
-	mutex_lock(&swhash->hlist_mutex);
-	swhash->online = false;
-	swevent_hlist_release(swhash);
-	mutex_unlock(&swhash->hlist_mutex);
 }
 #else
 static inline void perf_event_exit_cpu(int cpu) { }
@@ -9452,16 +9465,18 @@ static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
 static int __perf_cgroup_move(void *info)
 {
 	struct task_struct *task = info;
+	rcu_read_lock();
 	perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
+	rcu_read_unlock();
 	return 0;
 }
 
-static void perf_cgroup_attach(struct cgroup_subsys_state *css,
-			       struct cgroup_taskset *tset)
+static void perf_cgroup_attach(struct cgroup_taskset *tset)
 {
 	struct task_struct *task;
+	struct cgroup_subsys_state *css;
 
-	cgroup_taskset_for_each(task, tset)
+	cgroup_taskset_for_each(task, css, tset)
 		task_function_call(task, __perf_cgroup_move, task);
 }