perf_counter: fix counter freeing logic
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / perf_counter.c
index d6cc22271ef45cfcfd1a627449093a78801e0356..7af16d1c480fbf0c19d1c9ad740e8e68c2516007 100644 (file)
@@ -1,13 +1,16 @@
 /*
  * Performance counter core code
  *
- *  Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de>
- *  Copyright(C) 2008 Red Hat, Inc., Ingo Molnar
+ *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ *  Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
+ *  Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
  *
- *  For licencing details see kernel-base/COPYING
+ *  For licensing details see kernel-base/COPYING
  */
 
 #include <linux/fs.h>
+#include <linux/mm.h>
 #include <linux/cpu.h>
 #include <linux/smp.h>
 #include <linux/file.h>
 #include <linux/sysfs.h>
 #include <linux/ptrace.h>
 #include <linux/percpu.h>
+#include <linux/vmstat.h>
+#include <linux/hardirq.h>
+#include <linux/rculist.h>
 #include <linux/uaccess.h>
 #include <linux/syscalls.h>
 #include <linux/anon_inodes.h>
 #include <linux/kernel_stat.h>
 #include <linux/perf_counter.h>
-#include <linux/mm.h>
-#include <linux/vmstat.h>
-#include <linux/rculist.h>
+#include <linux/dcache.h>
+
+#include <asm/irq_regs.h>
 
 /*
  * Each CPU has a list of per CPU counters:
@@ -33,22 +39,30 @@ int perf_max_counters __read_mostly = 1;
 static int perf_reserved_percpu __read_mostly;
 static int perf_overcommit __read_mostly = 1;
 
+static atomic_t nr_counters __read_mostly;
+static atomic_t nr_mmap_tracking __read_mostly;
+static atomic_t nr_munmap_tracking __read_mostly;
+static atomic_t nr_comm_tracking __read_mostly;
+
+int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */
+int sysctl_perf_counter_mlock __read_mostly = 512; /* 'free' kb per user */
+
 /*
- * Mutex for (sysadmin-configurable) counter reservations:
+ * Lock for (sysadmin-configurable) counter reservations:
  */
-static DEFINE_MUTEX(perf_resource_mutex);
+static DEFINE_SPINLOCK(perf_resource_lock);
 
 /*
  * Architecture provided APIs - weak aliases:
  */
-extern __weak const struct hw_perf_counter_ops *
-hw_perf_counter_init(struct perf_counter *counter)
+extern __weak const struct pmu *hw_perf_counter_init(struct perf_counter *counter)
 {
        return NULL;
 }
 
-u64 __weak hw_perf_save_disable(void)          { return 0; }
-void __weak hw_perf_restore(u64 ctrl)          { barrier(); }
+void __weak hw_perf_disable(void)              { barrier(); }
+void __weak hw_perf_enable(void)               { barrier(); }
+
 void __weak hw_perf_counter_setup(int cpu)     { barrier(); }
 int __weak hw_perf_group_sched_in(struct perf_counter *group_leader,
               struct perf_cpu_context *cpuctx,
@@ -59,6 +73,30 @@ int __weak hw_perf_group_sched_in(struct perf_counter *group_leader,
 
 void __weak perf_counter_print_debug(void)     { }
 
+static DEFINE_PER_CPU(int, disable_count);
+
+void __perf_disable(void)
+{
+       __get_cpu_var(disable_count)++;
+}
+
+bool __perf_enable(void)
+{
+       return !--__get_cpu_var(disable_count);
+}
+
+void perf_disable(void)
+{
+       __perf_disable();
+       hw_perf_disable();
+}
+
+void perf_enable(void)
+{
+       if (__perf_enable())
+               hw_perf_enable();
+}
+
 static void
 list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
 {
@@ -69,12 +107,15 @@ list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
         * add it straight to the context's counter list, or to the group
         * leader's sibling list:
         */
-       if (counter->group_leader == counter)
+       if (group_leader == counter)
                list_add_tail(&counter->list_entry, &ctx->counter_list);
-       else
+       else {
                list_add_tail(&counter->list_entry, &group_leader->sibling_list);
+               group_leader->nr_siblings++;
+       }
 
        list_add_rcu(&counter->event_entry, &ctx->event_list);
+       ctx->nr_counters++;
 }
 
 static void
@@ -82,9 +123,14 @@ list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
 {
        struct perf_counter *sibling, *tmp;
 
+       ctx->nr_counters--;
+
        list_del_init(&counter->list_entry);
        list_del_rcu(&counter->event_entry);
 
+       if (counter->group_leader != counter)
+               counter->group_leader->nr_siblings--;
+
        /*
         * If this was a group counter with sibling counters then
         * upgrade the siblings to singleton counters by adding them
@@ -107,7 +153,8 @@ counter_sched_out(struct perf_counter *counter,
                return;
 
        counter->state = PERF_COUNTER_STATE_INACTIVE;
-       counter->hw_ops->disable(counter);
+       counter->tstamp_stopped = ctx->time;
+       counter->pmu->disable(counter);
        counter->oncpu = -1;
 
        if (!is_software_counter(counter))
@@ -151,7 +198,6 @@ static void __perf_counter_remove_from_context(void *info)
        struct perf_counter *counter = info;
        struct perf_counter_context *ctx = counter->ctx;
        unsigned long flags;
-       u64 perf_flags;
 
        /*
         * If this is a task context, we need to check whether it is
@@ -161,21 +207,19 @@ static void __perf_counter_remove_from_context(void *info)
        if (ctx->task && cpuctx->task_ctx != ctx)
                return;
 
-       curr_rq_lock_irq_save(&flags);
-       spin_lock(&ctx->lock);
+       spin_lock_irqsave(&ctx->lock, flags);
 
        counter_sched_out(counter, cpuctx, ctx);
 
        counter->task = NULL;
-       ctx->nr_counters--;
 
        /*
         * Protect the list operation against NMI by disabling the
         * counters on a global level. NOP for non NMI based counters.
         */
-       perf_flags = hw_perf_save_disable();
+       perf_disable();
        list_del_counter(counter, ctx);
-       hw_perf_restore(perf_flags);
+       perf_enable();
 
        if (!ctx->task) {
                /*
@@ -187,8 +231,7 @@ static void __perf_counter_remove_from_context(void *info)
                            perf_max_counters - perf_reserved_percpu);
        }
 
-       spin_unlock(&ctx->lock);
-       curr_rq_unlock_irq_restore(&flags);
+       spin_unlock_irqrestore(&ctx->lock, flags);
 }
 
 
@@ -235,13 +278,61 @@ retry:
         * succeed.
         */
        if (!list_empty(&counter->list_entry)) {
-               ctx->nr_counters--;
                list_del_counter(counter, ctx);
                counter->task = NULL;
        }
        spin_unlock_irq(&ctx->lock);
 }
 
+static inline u64 perf_clock(void)
+{
+       return cpu_clock(smp_processor_id());
+}
+
+/*
+ * Update the record of the current time in a context.
+ */
+static void update_context_time(struct perf_counter_context *ctx)
+{
+       u64 now = perf_clock();
+
+       ctx->time += now - ctx->timestamp;
+       ctx->timestamp = now;
+}
+
+/*
+ * Update the total_time_enabled and total_time_running fields for a counter.
+ */
+static void update_counter_times(struct perf_counter *counter)
+{
+       struct perf_counter_context *ctx = counter->ctx;
+       u64 run_end;
+
+       if (counter->state < PERF_COUNTER_STATE_INACTIVE)
+               return;
+
+       counter->total_time_enabled = ctx->time - counter->tstamp_enabled;
+
+       if (counter->state == PERF_COUNTER_STATE_INACTIVE)
+               run_end = counter->tstamp_stopped;
+       else
+               run_end = ctx->time;
+
+       counter->total_time_running = run_end - counter->tstamp_running;
+}
+
+/*
+ * Update total_time_enabled and total_time_running for all counters in a group.
+ */
+static void update_group_times(struct perf_counter *leader)
+{
+       struct perf_counter *counter;
+
+       update_counter_times(leader);
+       list_for_each_entry(counter, &leader->sibling_list, list_entry)
+               update_counter_times(counter);
+}
+
 /*
  * Cross CPU call to disable a performance counter
  */
@@ -259,14 +350,15 @@ static void __perf_counter_disable(void *info)
        if (ctx->task && cpuctx->task_ctx != ctx)
                return;
 
-       curr_rq_lock_irq_save(&flags);
-       spin_lock(&ctx->lock);
+       spin_lock_irqsave(&ctx->lock, flags);
 
        /*
         * If the counter is on, turn it off.
         * If it is in error state, leave it in error state.
         */
        if (counter->state >= PERF_COUNTER_STATE_INACTIVE) {
+               update_context_time(ctx);
+               update_counter_times(counter);
                if (counter == counter->group_leader)
                        group_sched_out(counter, cpuctx, ctx);
                else
@@ -274,8 +366,7 @@ static void __perf_counter_disable(void *info)
                counter->state = PERF_COUNTER_STATE_OFF;
        }
 
-       spin_unlock(&ctx->lock);
-       curr_rq_unlock_irq_restore(&flags);
+       spin_unlock_irqrestore(&ctx->lock, flags);
 }
 
 /*
@@ -311,30 +402,14 @@ static void perf_counter_disable(struct perf_counter *counter)
         * Since we have the lock this context can't be scheduled
         * in, so we can change the state safely.
         */
-       if (counter->state == PERF_COUNTER_STATE_INACTIVE)
+       if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
+               update_counter_times(counter);
                counter->state = PERF_COUNTER_STATE_OFF;
+       }
 
        spin_unlock_irq(&ctx->lock);
 }
 
-/*
- * Disable a counter and all its children.
- */
-static void perf_counter_disable_family(struct perf_counter *counter)
-{
-       struct perf_counter *child;
-
-       perf_counter_disable(counter);
-
-       /*
-        * Lock the mutex to protect the list of children
-        */
-       mutex_lock(&counter->mutex);
-       list_for_each_entry(child, &counter->child_list, child_list)
-               perf_counter_disable(child);
-       mutex_unlock(&counter->mutex);
-}
-
 static int
 counter_sched_in(struct perf_counter *counter,
                 struct perf_cpu_context *cpuctx,
@@ -351,12 +426,14 @@ counter_sched_in(struct perf_counter *counter,
         */
        smp_wmb();
 
-       if (counter->hw_ops->enable(counter)) {
+       if (counter->pmu->enable(counter)) {
                counter->state = PERF_COUNTER_STATE_INACTIVE;
                counter->oncpu = -1;
                return -EAGAIN;
        }
 
+       counter->tstamp_running += ctx->time - counter->tstamp_stopped;
+
        if (!is_software_counter(counter))
                cpuctx->active_oncpu++;
        ctx->nr_active++;
@@ -367,6 +444,54 @@ counter_sched_in(struct perf_counter *counter,
        return 0;
 }
 
+static int
+group_sched_in(struct perf_counter *group_counter,
+              struct perf_cpu_context *cpuctx,
+              struct perf_counter_context *ctx,
+              int cpu)
+{
+       struct perf_counter *counter, *partial_group;
+       int ret;
+
+       if (group_counter->state == PERF_COUNTER_STATE_OFF)
+               return 0;
+
+       ret = hw_perf_group_sched_in(group_counter, cpuctx, ctx, cpu);
+       if (ret)
+               return ret < 0 ? ret : 0;
+
+       group_counter->prev_state = group_counter->state;
+       if (counter_sched_in(group_counter, cpuctx, ctx, cpu))
+               return -EAGAIN;
+
+       /*
+        * Schedule in siblings as one group (if any):
+        */
+       list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
+               counter->prev_state = counter->state;
+               if (counter_sched_in(counter, cpuctx, ctx, cpu)) {
+                       partial_group = counter;
+                       goto group_error;
+               }
+       }
+
+       return 0;
+
+group_error:
+       /*
+        * Groups can be scheduled in as one unit only, so undo any
+        * partial group before returning:
+        */
+       list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
+               if (counter == partial_group)
+                       break;
+               counter_sched_out(counter, cpuctx, ctx);
+       }
+       counter_sched_out(group_counter, cpuctx, ctx);
+
+       return -EAGAIN;
+}
+
 /*
  * Return 1 for a group consisting entirely of software counters,
  * 0 if the group contains any hardware counters.
@@ -377,9 +502,11 @@ static int is_software_only_group(struct perf_counter *leader)
 
        if (!is_software_counter(leader))
                return 0;
+
        list_for_each_entry(counter, &leader->sibling_list, list_entry)
                if (!is_software_counter(counter))
                        return 0;
+
        return 1;
 }
 
@@ -414,6 +541,16 @@ static int group_can_go_on(struct perf_counter *counter,
        return can_add_hw;
 }
 
+static void add_counter_to_ctx(struct perf_counter *counter,
+                              struct perf_counter_context *ctx)
+{
+       list_add_counter(counter, ctx);
+       counter->prev_state = PERF_COUNTER_STATE_OFF;
+       counter->tstamp_enabled = ctx->time;
+       counter->tstamp_running = ctx->time;
+       counter->tstamp_stopped = ctx->time;
+}
+
 /*
  * Cross CPU call to install and enable a performance counter
  */
@@ -425,7 +562,6 @@ static void __perf_install_in_context(void *info)
        struct perf_counter *leader = counter->group_leader;
        int cpu = smp_processor_id();
        unsigned long flags;
-       u64 perf_flags;
        int err;
 
        /*
@@ -436,18 +572,16 @@ static void __perf_install_in_context(void *info)
        if (ctx->task && cpuctx->task_ctx != ctx)
                return;
 
-       curr_rq_lock_irq_save(&flags);
-       spin_lock(&ctx->lock);
+       spin_lock_irqsave(&ctx->lock, flags);
+       update_context_time(ctx);
 
        /*
         * Protect the list operation against NMI by disabling the
         * counters on a global level. NOP for non NMI based counters.
         */
-       perf_flags = hw_perf_save_disable();
+       perf_disable();
 
-       list_add_counter(counter, ctx);
-       ctx->nr_counters++;
-       counter->prev_state = PERF_COUNTER_STATE_OFF;
+       add_counter_to_ctx(counter, ctx);
 
        /*
         * Don't put the counter on if it is disabled or if
@@ -475,18 +609,19 @@ static void __perf_install_in_context(void *info)
                 */
                if (leader != counter)
                        group_sched_out(leader, cpuctx, ctx);
-               if (leader->hw_event.pinned)
+               if (leader->hw_event.pinned) {
+                       update_group_times(leader);
                        leader->state = PERF_COUNTER_STATE_ERROR;
+               }
        }
 
        if (!err && !ctx->task && cpuctx->max_pertask)
                cpuctx->max_pertask--;
 
  unlock:
-       hw_perf_restore(perf_flags);
+       perf_enable();
 
-       spin_unlock(&ctx->lock);
-       curr_rq_unlock_irq_restore(&flags);
+       spin_unlock_irqrestore(&ctx->lock, flags);
 }
 
 /*
@@ -537,10 +672,8 @@ retry:
         * can add the counter safely, if it the call above did not
         * succeed.
         */
-       if (list_empty(&counter->list_entry)) {
-               list_add_counter(counter, ctx);
-               ctx->nr_counters++;
-       }
+       if (list_empty(&counter->list_entry))
+               add_counter_to_ctx(counter, ctx);
        spin_unlock_irq(&ctx->lock);
 }
 
@@ -563,13 +696,14 @@ static void __perf_counter_enable(void *info)
        if (ctx->task && cpuctx->task_ctx != ctx)
                return;
 
-       curr_rq_lock_irq_save(&flags);
-       spin_lock(&ctx->lock);
+       spin_lock_irqsave(&ctx->lock, flags);
+       update_context_time(ctx);
 
        counter->prev_state = counter->state;
        if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
                goto unlock;
        counter->state = PERF_COUNTER_STATE_INACTIVE;
+       counter->tstamp_enabled = ctx->time - counter->total_time_enabled;
 
        /*
         * If the counter is in a group and isn't the group leader,
@@ -578,11 +712,18 @@ static void __perf_counter_enable(void *info)
        if (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE)
                goto unlock;
 
-       if (!group_can_go_on(counter, cpuctx, 1))
+       if (!group_can_go_on(counter, cpuctx, 1)) {
                err = -EEXIST;
-       else
-               err = counter_sched_in(counter, cpuctx, ctx,
-                                      smp_processor_id());
+       } else {
+               perf_disable();
+               if (counter == leader)
+                       err = group_sched_in(counter, cpuctx, ctx,
+                                            smp_processor_id());
+               else
+                       err = counter_sched_in(counter, cpuctx, ctx,
+                                              smp_processor_id());
+               perf_enable();
+       }
 
        if (err) {
                /*
@@ -591,13 +732,14 @@ static void __perf_counter_enable(void *info)
                 */
                if (leader != counter)
                        group_sched_out(leader, cpuctx, ctx);
-               if (leader->hw_event.pinned)
+               if (leader->hw_event.pinned) {
+                       update_group_times(leader);
                        leader->state = PERF_COUNTER_STATE_ERROR;
+               }
        }
 
  unlock:
-       spin_unlock(&ctx->lock);
-       curr_rq_unlock_irq_restore(&flags);
+       spin_unlock_irqrestore(&ctx->lock, flags);
 }
 
 /*
@@ -648,47 +790,46 @@ static void perf_counter_enable(struct perf_counter *counter)
         * Since we have the lock this context can't be scheduled
         * in, so we can change the state safely.
         */
-       if (counter->state == PERF_COUNTER_STATE_OFF)
+       if (counter->state == PERF_COUNTER_STATE_OFF) {
                counter->state = PERF_COUNTER_STATE_INACTIVE;
+               counter->tstamp_enabled =
+                       ctx->time - counter->total_time_enabled;
+       }
  out:
        spin_unlock_irq(&ctx->lock);
 }
 
-/*
- * Enable a counter and all its children.
- */
-static void perf_counter_enable_family(struct perf_counter *counter)
+static int perf_counter_refresh(struct perf_counter *counter, int refresh)
 {
-       struct perf_counter *child;
+       /*
+        * not supported on inherited counters
+        */
+       if (counter->hw_event.inherit)
+               return -EINVAL;
 
+       atomic_add(refresh, &counter->event_limit);
        perf_counter_enable(counter);
 
-       /*
-        * Lock the mutex to protect the list of children
-        */
-       mutex_lock(&counter->mutex);
-       list_for_each_entry(child, &counter->child_list, child_list)
-               perf_counter_enable(child);
-       mutex_unlock(&counter->mutex);
+       return 0;
 }
 
 void __perf_counter_sched_out(struct perf_counter_context *ctx,
                              struct perf_cpu_context *cpuctx)
 {
        struct perf_counter *counter;
-       u64 flags;
 
        spin_lock(&ctx->lock);
        ctx->is_active = 0;
        if (likely(!ctx->nr_counters))
                goto out;
+       update_context_time(ctx);
 
-       flags = hw_perf_save_disable();
+       perf_disable();
        if (ctx->nr_active) {
                list_for_each_entry(counter, &ctx->counter_list, list_entry)
                        group_sched_out(counter, cpuctx, ctx);
        }
-       hw_perf_restore(flags);
+       perf_enable();
  out:
        spin_unlock(&ctx->lock);
 }
@@ -708,66 +849,31 @@ void perf_counter_task_sched_out(struct task_struct *task, int cpu)
 {
        struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
        struct perf_counter_context *ctx = &task->perf_counter_ctx;
+       struct pt_regs *regs;
 
        if (likely(!cpuctx->task_ctx))
                return;
 
+       update_context_time(ctx);
+
+       regs = task_pt_regs(task);
+       perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES, 1, 1, regs, 0);
        __perf_counter_sched_out(ctx, cpuctx);
 
        cpuctx->task_ctx = NULL;
 }
 
-static void perf_counter_cpu_sched_out(struct perf_cpu_context *cpuctx)
+static void __perf_counter_task_sched_out(struct perf_counter_context *ctx)
 {
-       __perf_counter_sched_out(&cpuctx->ctx, cpuctx);
+       struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+
+       __perf_counter_sched_out(ctx, cpuctx);
+       cpuctx->task_ctx = NULL;
 }
 
-static int
-group_sched_in(struct perf_counter *group_counter,
-              struct perf_cpu_context *cpuctx,
-              struct perf_counter_context *ctx,
-              int cpu)
+static void perf_counter_cpu_sched_out(struct perf_cpu_context *cpuctx)
 {
-       struct perf_counter *counter, *partial_group;
-       int ret;
-
-       if (group_counter->state == PERF_COUNTER_STATE_OFF)
-               return 0;
-
-       ret = hw_perf_group_sched_in(group_counter, cpuctx, ctx, cpu);
-       if (ret)
-               return ret < 0 ? ret : 0;
-
-       group_counter->prev_state = group_counter->state;
-       if (counter_sched_in(group_counter, cpuctx, ctx, cpu))
-               return -EAGAIN;
-
-       /*
-        * Schedule in siblings as one group (if any):
-        */
-       list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
-               counter->prev_state = counter->state;
-               if (counter_sched_in(counter, cpuctx, ctx, cpu)) {
-                       partial_group = counter;
-                       goto group_error;
-               }
-       }
-
-       return 0;
-
-group_error:
-       /*
-        * Groups can be scheduled in as one unit only, so undo any
-        * partial group before returning:
-        */
-       list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
-               if (counter == partial_group)
-                       break;
-               counter_sched_out(counter, cpuctx, ctx);
-       }
-       counter_sched_out(group_counter, cpuctx, ctx);
-
-       return -EAGAIN;
+       __perf_counter_sched_out(&cpuctx->ctx, cpuctx);
 }
 
 static void
@@ -775,7 +881,6 @@ __perf_counter_sched_in(struct perf_counter_context *ctx,
                        struct perf_cpu_context *cpuctx, int cpu)
 {
        struct perf_counter *counter;
-       u64 flags;
        int can_add_hw = 1;
 
        spin_lock(&ctx->lock);
@@ -783,7 +888,9 @@ __perf_counter_sched_in(struct perf_counter_context *ctx,
        if (likely(!ctx->nr_counters))
                goto out;
 
-       flags = hw_perf_save_disable();
+       ctx->timestamp = perf_clock();
+
+       perf_disable();
 
        /*
         * First go through the list and put on any pinned groups
@@ -803,8 +910,10 @@ __perf_counter_sched_in(struct perf_counter_context *ctx,
                 * If this pinned group hasn't been scheduled,
                 * put it in error state.
                 */
-               if (counter->state == PERF_COUNTER_STATE_INACTIVE)
+               if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
+                       update_group_times(counter);
                        counter->state = PERF_COUNTER_STATE_ERROR;
+               }
        }
 
        list_for_each_entry(counter, &ctx->counter_list, list_entry) {
@@ -828,7 +937,7 @@ __perf_counter_sched_in(struct perf_counter_context *ctx,
                                can_add_hw = 0;
                }
        }
-       hw_perf_restore(flags);
+       perf_enable();
  out:
        spin_unlock(&ctx->lock);
 }
@@ -866,37 +975,31 @@ int perf_counter_task_disable(void)
        struct perf_counter_context *ctx = &curr->perf_counter_ctx;
        struct perf_counter *counter;
        unsigned long flags;
-       u64 perf_flags;
-       int cpu;
 
        if (likely(!ctx->nr_counters))
                return 0;
 
-       curr_rq_lock_irq_save(&flags);
-       cpu = smp_processor_id();
-
-       /* force the update of the task clock: */
-       __task_delta_exec(curr, 1);
+       local_irq_save(flags);
 
-       perf_counter_task_sched_out(curr, cpu);
+       __perf_counter_task_sched_out(ctx);
 
        spin_lock(&ctx->lock);
 
        /*
         * Disable all the counters:
         */
-       perf_flags = hw_perf_save_disable();
+       perf_disable();
 
        list_for_each_entry(counter, &ctx->counter_list, list_entry) {
-               if (counter->state != PERF_COUNTER_STATE_ERROR)
+               if (counter->state != PERF_COUNTER_STATE_ERROR) {
+                       update_group_times(counter);
                        counter->state = PERF_COUNTER_STATE_OFF;
+               }
        }
 
-       hw_perf_restore(perf_flags);
+       perf_enable();
 
-       spin_unlock(&ctx->lock);
-
-       curr_rq_unlock_irq_restore(&flags);
+       spin_unlock_irqrestore(&ctx->lock, flags);
 
        return 0;
 }
@@ -907,51 +1010,80 @@ int perf_counter_task_enable(void)
        struct perf_counter_context *ctx = &curr->perf_counter_ctx;
        struct perf_counter *counter;
        unsigned long flags;
-       u64 perf_flags;
        int cpu;
 
        if (likely(!ctx->nr_counters))
                return 0;
 
-       curr_rq_lock_irq_save(&flags);
+       local_irq_save(flags);
        cpu = smp_processor_id();
 
-       /* force the update of the task clock: */
-       __task_delta_exec(curr, 1);
-
-       perf_counter_task_sched_out(curr, cpu);
+       __perf_counter_task_sched_out(ctx);
 
        spin_lock(&ctx->lock);
 
        /*
         * Disable all the counters:
         */
-       perf_flags = hw_perf_save_disable();
+       perf_disable();
 
        list_for_each_entry(counter, &ctx->counter_list, list_entry) {
                if (counter->state > PERF_COUNTER_STATE_OFF)
                        continue;
                counter->state = PERF_COUNTER_STATE_INACTIVE;
+               counter->tstamp_enabled =
+                       ctx->time - counter->total_time_enabled;
                counter->hw_event.disabled = 0;
        }
-       hw_perf_restore(perf_flags);
+       perf_enable();
 
        spin_unlock(&ctx->lock);
 
        perf_counter_task_sched_in(curr, cpu);
 
-       curr_rq_unlock_irq_restore(&flags);
+       local_irq_restore(flags);
 
        return 0;
 }
 
+void perf_adjust_freq(struct perf_counter_context *ctx)
+{
+       struct perf_counter *counter;
+       u64 irq_period;
+       u64 events, period;
+       s64 delta;
+
+       spin_lock(&ctx->lock);
+       list_for_each_entry(counter, &ctx->counter_list, list_entry) {
+               if (counter->state != PERF_COUNTER_STATE_ACTIVE)
+                       continue;
+
+               if (!counter->hw_event.freq || !counter->hw_event.irq_freq)
+                       continue;
+
+               events = HZ * counter->hw.interrupts * counter->hw.irq_period;
+               period = div64_u64(events, counter->hw_event.irq_freq);
+
+               delta = (s64)(1 + period - counter->hw.irq_period);
+               delta >>= 1;
+
+               irq_period = counter->hw.irq_period + delta;
+
+               if (!irq_period)
+                       irq_period = 1;
+
+               counter->hw.irq_period = irq_period;
+               counter->hw.interrupts = 0;
+       }
+       spin_unlock(&ctx->lock);
+}
+
 /*
  * Round-robin a context's counters:
  */
 static void rotate_ctx(struct perf_counter_context *ctx)
 {
        struct perf_counter *counter;
-       u64 perf_flags;
 
        if (!ctx->nr_counters)
                return;
@@ -960,32 +1092,37 @@ static void rotate_ctx(struct perf_counter_context *ctx)
        /*
         * Rotate the first entry last (works just fine for group counters too):
         */
-       perf_flags = hw_perf_save_disable();
+       perf_disable();
        list_for_each_entry(counter, &ctx->counter_list, list_entry) {
                list_move_tail(&counter->list_entry, &ctx->counter_list);
                break;
        }
-       hw_perf_restore(perf_flags);
+       perf_enable();
 
        spin_unlock(&ctx->lock);
 }
 
 void perf_counter_task_tick(struct task_struct *curr, int cpu)
 {
-       struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
-       struct perf_counter_context *ctx = &curr->perf_counter_ctx;
-       const int rotate_percpu = 0;
+       struct perf_cpu_context *cpuctx;
+       struct perf_counter_context *ctx;
+
+       if (!atomic_read(&nr_counters))
+               return;
+
+       cpuctx = &per_cpu(perf_cpu_context, cpu);
+       ctx = &curr->perf_counter_ctx;
+
+       perf_adjust_freq(&cpuctx->ctx);
+       perf_adjust_freq(ctx);
 
-       if (rotate_percpu)
-               perf_counter_cpu_sched_out(cpuctx);
-       perf_counter_task_sched_out(curr, cpu);
+       perf_counter_cpu_sched_out(cpuctx);
+       __perf_counter_task_sched_out(ctx);
 
-       if (rotate_percpu)
-               rotate_ctx(&cpuctx->ctx);
+       rotate_ctx(&cpuctx->ctx);
        rotate_ctx(ctx);
 
-       if (rotate_percpu)
-               perf_counter_cpu_sched_in(cpuctx, cpu);
+       perf_counter_cpu_sched_in(cpuctx, cpu);
        perf_counter_task_sched_in(curr, cpu);
 }
 
@@ -995,11 +1132,15 @@ void perf_counter_task_tick(struct task_struct *curr, int cpu)
 static void __read(void *info)
 {
        struct perf_counter *counter = info;
+       struct perf_counter_context *ctx = counter->ctx;
        unsigned long flags;
 
-       curr_rq_lock_irq_save(&flags);
-       counter->hw_ops->read(counter);
-       curr_rq_unlock_irq_restore(&flags);
+       local_irq_save(flags);
+       if (ctx->is_active)
+               update_context_time(ctx);
+       counter->pmu->read(counter);
+       update_counter_times(counter);
+       local_irq_restore(flags);
 }
 
 static u64 perf_counter_read(struct perf_counter *counter)
@@ -1011,71 +1152,13 @@ static u64 perf_counter_read(struct perf_counter *counter)
        if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
                smp_call_function_single(counter->oncpu,
                                         __read, counter, 1);
+       } else if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
+               update_counter_times(counter);
        }
 
        return atomic64_read(&counter->count);
 }
 
-/*
- * Cross CPU call to switch performance data pointers
- */
-static void __perf_switch_irq_data(void *info)
-{
-       struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
-       struct perf_counter *counter = info;
-       struct perf_counter_context *ctx = counter->ctx;
-       struct perf_data *oldirqdata = counter->irqdata;
-
-       /*
-        * If this is a task context, we need to check whether it is
-        * the current task context of this cpu. If not it has been
-        * scheduled out before the smp call arrived.
-        */
-       if (ctx->task) {
-               if (cpuctx->task_ctx != ctx)
-                       return;
-               spin_lock(&ctx->lock);
-       }
-
-       /* Change the pointer NMI safe */
-       atomic_long_set((atomic_long_t *)&counter->irqdata,
-                       (unsigned long) counter->usrdata);
-       counter->usrdata = oldirqdata;
-
-       if (ctx->task)
-               spin_unlock(&ctx->lock);
-}
-
-static struct perf_data *perf_switch_irq_data(struct perf_counter *counter)
-{
-       struct perf_counter_context *ctx = counter->ctx;
-       struct perf_data *oldirqdata = counter->irqdata;
-       struct task_struct *task = ctx->task;
-
-       if (!task) {
-               smp_call_function_single(counter->cpu,
-                                        __perf_switch_irq_data,
-                                        counter, 1);
-               return counter->usrdata;
-       }
-
-retry:
-       spin_lock_irq(&ctx->lock);
-       if (counter->state != PERF_COUNTER_STATE_ACTIVE) {
-               counter->irqdata = counter->usrdata;
-               counter->usrdata = oldirqdata;
-               spin_unlock_irq(&ctx->lock);
-               return oldirqdata;
-       }
-       spin_unlock_irq(&ctx->lock);
-       task_oncpu_function_call(task, __perf_switch_irq_data, counter);
-       /* Might have failed, because task was scheduled out */
-       if (counter->irqdata == oldirqdata)
-               goto retry;
-
-       return counter->usrdata;
-}
-
 static void put_context(struct perf_counter_context *ctx)
 {
        if (ctx->task)
@@ -1093,7 +1176,7 @@ static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
         */
        if (cpu != -1) {
                /* Must be root to operate on a CPU counter: */
-               if (!capable(CAP_SYS_ADMIN))
+               if (sysctl_perf_counter_priv && !capable(CAP_SYS_ADMIN))
                        return ERR_PTR(-EACCES);
 
                if (cpu < 0 || cpu > num_possible_cpus())
@@ -1145,6 +1228,26 @@ static void free_counter_rcu(struct rcu_head *head)
        kfree(counter);
 }
 
+static void perf_pending_sync(struct perf_counter *counter);
+
+static void free_counter(struct perf_counter *counter)
+{
+       perf_pending_sync(counter);
+
+       atomic_dec(&nr_counters);
+       if (counter->hw_event.mmap)
+               atomic_dec(&nr_mmap_tracking);
+       if (counter->hw_event.munmap)
+               atomic_dec(&nr_munmap_tracking);
+       if (counter->hw_event.comm)
+               atomic_dec(&nr_comm_tracking);
+
+       if (counter->destroy)
+               counter->destroy(counter);
+
+       call_rcu(&counter->rcu_head, free_counter_rcu);
+}
+
 /*
  * Called when the last reference to the file is gone.
  */
@@ -1163,7 +1266,7 @@ static int perf_release(struct inode *inode, struct file *file)
        mutex_unlock(&counter->mutex);
        mutex_unlock(&ctx->mutex);
 
-       call_rcu(&counter->rcu_head, free_counter_rcu);
+       free_counter(counter);
        put_context(ctx);
 
        return 0;
@@ -1175,10 +1278,8 @@ static int perf_release(struct inode *inode, struct file *file)
 static ssize_t
 perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count)
 {
-       u64 cntval;
-
-       if (count != sizeof(cntval))
-               return -EINVAL;
+       u64 values[3];
+       int n;
 
        /*
         * Return end-of-file for a read on a counter that is in
@@ -1189,156 +1290,1154 @@ perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count)
                return 0;
 
        mutex_lock(&counter->mutex);
-       cntval = perf_counter_read(counter);
+       values[0] = perf_counter_read(counter);
+       n = 1;
+       if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+               values[n++] = counter->total_time_enabled +
+                       atomic64_read(&counter->child_total_time_enabled);
+       if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+               values[n++] = counter->total_time_running +
+                       atomic64_read(&counter->child_total_time_running);
        mutex_unlock(&counter->mutex);
 
-       return put_user(cntval, (u64 __user *) buf) ? -EFAULT : sizeof(cntval);
+       if (count < n * sizeof(u64))
+               return -EINVAL;
+       count = n * sizeof(u64);
+
+       if (copy_to_user(buf, values, count))
+               return -EFAULT;
+
+       return count;
+}
+
+static ssize_t
+perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+       struct perf_counter *counter = file->private_data;
+
+       return perf_read_hw(counter, buf, count);
+}
+
+static unsigned int perf_poll(struct file *file, poll_table *wait)
+{
+       struct perf_counter *counter = file->private_data;
+       struct perf_mmap_data *data;
+       unsigned int events = POLL_HUP;
+
+       rcu_read_lock();
+       data = rcu_dereference(counter->data);
+       if (data)
+               events = atomic_xchg(&data->poll, 0);
+       rcu_read_unlock();
+
+       poll_wait(file, &counter->waitq, wait);
+
+       return events;
+}
+
+static void perf_counter_reset(struct perf_counter *counter)
+{
+       (void)perf_counter_read(counter);
+       atomic64_set(&counter->count, 0);
+       perf_counter_update_userpage(counter);
+}
+
+static void perf_counter_for_each_sibling(struct perf_counter *counter,
+                                         void (*func)(struct perf_counter *))
+{
+       struct perf_counter_context *ctx = counter->ctx;
+       struct perf_counter *sibling;
+
+       spin_lock_irq(&ctx->lock);
+       counter = counter->group_leader;
+
+       func(counter);
+       list_for_each_entry(sibling, &counter->sibling_list, list_entry)
+               func(sibling);
+       spin_unlock_irq(&ctx->lock);
+}
+
+static void perf_counter_for_each_child(struct perf_counter *counter,
+                                       void (*func)(struct perf_counter *))
+{
+       struct perf_counter *child;
+
+       mutex_lock(&counter->mutex);
+       func(counter);
+       list_for_each_entry(child, &counter->child_list, child_list)
+               func(child);
+       mutex_unlock(&counter->mutex);
+}
+
+static void perf_counter_for_each(struct perf_counter *counter,
+                                 void (*func)(struct perf_counter *))
+{
+       struct perf_counter *child;
+
+       mutex_lock(&counter->mutex);
+       perf_counter_for_each_sibling(counter, func);
+       list_for_each_entry(child, &counter->child_list, child_list)
+               perf_counter_for_each_sibling(child, func);
+       mutex_unlock(&counter->mutex);
+}
+
+static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+       struct perf_counter *counter = file->private_data;
+       void (*func)(struct perf_counter *);
+       u32 flags = arg;
+
+       switch (cmd) {
+       case PERF_COUNTER_IOC_ENABLE:
+               func = perf_counter_enable;
+               break;
+       case PERF_COUNTER_IOC_DISABLE:
+               func = perf_counter_disable;
+               break;
+       case PERF_COUNTER_IOC_RESET:
+               func = perf_counter_reset;
+               break;
+
+       case PERF_COUNTER_IOC_REFRESH:
+               return perf_counter_refresh(counter, arg);
+       default:
+               return -ENOTTY;
+       }
+
+       if (flags & PERF_IOC_FLAG_GROUP)
+               perf_counter_for_each(counter, func);
+       else
+               perf_counter_for_each_child(counter, func);
+
+       return 0;
+}
+
+/*
+ * Callers need to ensure there can be no nesting of this function, otherwise
+ * the seqlock logic goes bad. We can not serialize this because the arch
+ * code calls this from NMI context.
+ */
+void perf_counter_update_userpage(struct perf_counter *counter)
+{
+       struct perf_mmap_data *data;
+       struct perf_counter_mmap_page *userpg;
+
+       rcu_read_lock();
+       data = rcu_dereference(counter->data);
+       if (!data)
+               goto unlock;
+
+       userpg = data->user_page;
+
+       /*
+        * Disable preemption so as to not let the corresponding user-space
+        * spin too long if we get preempted.
+        */
+       preempt_disable();
+       ++userpg->lock;
+       barrier();
+       userpg->index = counter->hw.idx;
+       userpg->offset = atomic64_read(&counter->count);
+       if (counter->state == PERF_COUNTER_STATE_ACTIVE)
+               userpg->offset -= atomic64_read(&counter->hw.prev_count);
+
+       barrier();
+       ++userpg->lock;
+       preempt_enable();
+unlock:
+       rcu_read_unlock();
+}
+
+static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+       struct perf_counter *counter = vma->vm_file->private_data;
+       struct perf_mmap_data *data;
+       int ret = VM_FAULT_SIGBUS;
+
+       rcu_read_lock();
+       data = rcu_dereference(counter->data);
+       if (!data)
+               goto unlock;
+
+       if (vmf->pgoff == 0) {
+               vmf->page = virt_to_page(data->user_page);
+       } else {
+               int nr = vmf->pgoff - 1;
+
+               if ((unsigned)nr > data->nr_pages)
+                       goto unlock;
+
+               vmf->page = virt_to_page(data->data_pages[nr]);
+       }
+       get_page(vmf->page);
+       ret = 0;
+unlock:
+       rcu_read_unlock();
+
+       return ret;
+}
+
+static int perf_mmap_data_alloc(struct perf_counter *counter, int nr_pages)
+{
+       struct perf_mmap_data *data;
+       unsigned long size;
+       int i;
+
+       WARN_ON(atomic_read(&counter->mmap_count));
+
+       size = sizeof(struct perf_mmap_data);
+       size += nr_pages * sizeof(void *);
+
+       data = kzalloc(size, GFP_KERNEL);
+       if (!data)
+               goto fail;
+
+       data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
+       if (!data->user_page)
+               goto fail_user_page;
+
+       for (i = 0; i < nr_pages; i++) {
+               data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
+               if (!data->data_pages[i])
+                       goto fail_data_pages;
+       }
+
+       data->nr_pages = nr_pages;
+       atomic_set(&data->lock, -1);
+
+       rcu_assign_pointer(counter->data, data);
+
+       return 0;
+
+fail_data_pages:
+       for (i--; i >= 0; i--)
+               free_page((unsigned long)data->data_pages[i]);
+
+       free_page((unsigned long)data->user_page);
+
+fail_user_page:
+       kfree(data);
+
+fail:
+       return -ENOMEM;
+}
+
+static void __perf_mmap_data_free(struct rcu_head *rcu_head)
+{
+       struct perf_mmap_data *data = container_of(rcu_head,
+                       struct perf_mmap_data, rcu_head);
+       int i;
+
+       free_page((unsigned long)data->user_page);
+       for (i = 0; i < data->nr_pages; i++)
+               free_page((unsigned long)data->data_pages[i]);
+       kfree(data);
+}
+
+static void perf_mmap_data_free(struct perf_counter *counter)
+{
+       struct perf_mmap_data *data = counter->data;
+
+       WARN_ON(atomic_read(&counter->mmap_count));
+
+       rcu_assign_pointer(counter->data, NULL);
+       call_rcu(&data->rcu_head, __perf_mmap_data_free);
+}
+
+static void perf_mmap_open(struct vm_area_struct *vma)
+{
+       struct perf_counter *counter = vma->vm_file->private_data;
+
+       atomic_inc(&counter->mmap_count);
+}
+
+static void perf_mmap_close(struct vm_area_struct *vma)
+{
+       struct perf_counter *counter = vma->vm_file->private_data;
+
+       if (atomic_dec_and_mutex_lock(&counter->mmap_count,
+                                     &counter->mmap_mutex)) {
+               struct user_struct *user = current_user();
+
+               atomic_long_sub(counter->data->nr_pages + 1, &user->locked_vm);
+               vma->vm_mm->locked_vm -= counter->data->nr_locked;
+               perf_mmap_data_free(counter);
+               mutex_unlock(&counter->mmap_mutex);
+       }
+}
+
+static struct vm_operations_struct perf_mmap_vmops = {
+       .open  = perf_mmap_open,
+       .close = perf_mmap_close,
+       .fault = perf_mmap_fault,
+};
+
+static int perf_mmap(struct file *file, struct vm_area_struct *vma)
+{
+       struct perf_counter *counter = file->private_data;
+       struct user_struct *user = current_user();
+       unsigned long vma_size;
+       unsigned long nr_pages;
+       unsigned long user_locked, user_lock_limit;
+       unsigned long locked, lock_limit;
+       long user_extra, extra;
+       int ret = 0;
+
+       if (!(vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_WRITE))
+               return -EINVAL;
+
+       vma_size = vma->vm_end - vma->vm_start;
+       nr_pages = (vma_size / PAGE_SIZE) - 1;
+
+       /*
+        * If we have data pages ensure they're a power-of-two number, so we
+        * can do bitmasks instead of modulo.
+        */
+       if (nr_pages != 0 && !is_power_of_2(nr_pages))
+               return -EINVAL;
+
+       if (vma_size != PAGE_SIZE * (1 + nr_pages))
+               return -EINVAL;
+
+       if (vma->vm_pgoff != 0)
+               return -EINVAL;
+
+       mutex_lock(&counter->mmap_mutex);
+       if (atomic_inc_not_zero(&counter->mmap_count)) {
+               if (nr_pages != counter->data->nr_pages)
+                       ret = -EINVAL;
+               goto unlock;
+       }
+
+       user_extra = nr_pages + 1;
+       user_lock_limit = sysctl_perf_counter_mlock >> (PAGE_SHIFT - 10);
+       user_locked = atomic_long_read(&user->locked_vm) + user_extra;
+
+       extra = 0;
+       if (user_locked > user_lock_limit)
+               extra = user_locked - user_lock_limit;
+
+       lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+       lock_limit >>= PAGE_SHIFT;
+       locked = vma->vm_mm->locked_vm + extra;
+
+       if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
+               ret = -EPERM;
+               goto unlock;
+       }
+
+       WARN_ON(counter->data);
+       ret = perf_mmap_data_alloc(counter, nr_pages);
+       if (ret)
+               goto unlock;
+
+       atomic_set(&counter->mmap_count, 1);
+       atomic_long_add(user_extra, &user->locked_vm);
+       vma->vm_mm->locked_vm += extra;
+       counter->data->nr_locked = extra;
+unlock:
+       mutex_unlock(&counter->mmap_mutex);
+
+       vma->vm_flags &= ~VM_MAYWRITE;
+       vma->vm_flags |= VM_RESERVED;
+       vma->vm_ops = &perf_mmap_vmops;
+
+       return ret;
+}
+
+static int perf_fasync(int fd, struct file *filp, int on)
+{
+       struct perf_counter *counter = filp->private_data;
+       struct inode *inode = filp->f_path.dentry->d_inode;
+       int retval;
+
+       mutex_lock(&inode->i_mutex);
+       retval = fasync_helper(fd, filp, on, &counter->fasync);
+       mutex_unlock(&inode->i_mutex);
+
+       if (retval < 0)
+               return retval;
+
+       return 0;
+}
+
+static const struct file_operations perf_fops = {
+       .release                = perf_release,
+       .read                   = perf_read,
+       .poll                   = perf_poll,
+       .unlocked_ioctl         = perf_ioctl,
+       .compat_ioctl           = perf_ioctl,
+       .mmap                   = perf_mmap,
+       .fasync                 = perf_fasync,
+};
+
+/*
+ * Perf counter wakeup
+ *
+ * If there's data, ensure we set the poll() state and publish everything
+ * to user-space before waking everybody up.
+ */
+
+void perf_counter_wakeup(struct perf_counter *counter)
+{
+       wake_up_all(&counter->waitq);
+
+       if (counter->pending_kill) {
+               kill_fasync(&counter->fasync, SIGIO, counter->pending_kill);
+               counter->pending_kill = 0;
+       }
+}
+
+/*
+ * Pending wakeups
+ *
+ * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
+ *
+ * The NMI bit means we cannot possibly take locks. Therefore, maintain a
+ * single linked list and use cmpxchg() to add entries lockless.
+ */
+
+static void perf_pending_counter(struct perf_pending_entry *entry)
+{
+       struct perf_counter *counter = container_of(entry,
+                       struct perf_counter, pending);
+
+       if (counter->pending_disable) {
+               counter->pending_disable = 0;
+               perf_counter_disable(counter);
+       }
+
+       if (counter->pending_wakeup) {
+               counter->pending_wakeup = 0;
+               perf_counter_wakeup(counter);
+       }
+}
+
+#define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
+
+static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
+       PENDING_TAIL,
+};
+
+static void perf_pending_queue(struct perf_pending_entry *entry,
+                              void (*func)(struct perf_pending_entry *))
+{
+       struct perf_pending_entry **head;
+
+       if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
+               return;
+
+       entry->func = func;
+
+       head = &get_cpu_var(perf_pending_head);
+
+       do {
+               entry->next = *head;
+       } while (cmpxchg(head, entry->next, entry) != entry->next);
+
+       set_perf_counter_pending();
+
+       put_cpu_var(perf_pending_head);
+}
+
+static int __perf_pending_run(void)
+{
+       struct perf_pending_entry *list;
+       int nr = 0;
+
+       list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
+       while (list != PENDING_TAIL) {
+               void (*func)(struct perf_pending_entry *);
+               struct perf_pending_entry *entry = list;
+
+               list = list->next;
+
+               func = entry->func;
+               entry->next = NULL;
+               /*
+                * Ensure we observe the unqueue before we issue the wakeup,
+                * so that we won't be waiting forever.
+                * -- see perf_not_pending().
+                */
+               smp_wmb();
+
+               func(entry);
+               nr++;
+       }
+
+       return nr;
+}
+
+static inline int perf_not_pending(struct perf_counter *counter)
+{
+       /*
+        * If we flush on whatever cpu we run, there is a chance we don't
+        * need to wait.
+        */
+       get_cpu();
+       __perf_pending_run();
+       put_cpu();
+
+       /*
+        * Ensure we see the proper queue state before going to sleep
+        * so that we do not miss the wakeup. -- see perf_pending_handle()
+        */
+       smp_rmb();
+       return counter->pending.next == NULL;
+}
+
+static void perf_pending_sync(struct perf_counter *counter)
+{
+       wait_event(counter->waitq, perf_not_pending(counter));
+}
+
+void perf_counter_do_pending(void)
+{
+       __perf_pending_run();
+}
+
+/*
+ * Callchain support -- arch specific
+ */
+
+__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
+{
+       return NULL;
+}
+
+/*
+ * Output
+ */
+
+struct perf_output_handle {
+       struct perf_counter     *counter;
+       struct perf_mmap_data   *data;
+       unsigned int            offset;
+       unsigned int            head;
+       int                     nmi;
+       int                     overflow;
+       int                     locked;
+       unsigned long           flags;
+};
+
+static void perf_output_wakeup(struct perf_output_handle *handle)
+{
+       atomic_set(&handle->data->poll, POLL_IN);
+
+       if (handle->nmi) {
+               handle->counter->pending_wakeup = 1;
+               perf_pending_queue(&handle->counter->pending,
+                                  perf_pending_counter);
+       } else
+               perf_counter_wakeup(handle->counter);
+}
+
+/*
+ * Curious locking construct.
+ *
+ * We need to ensure a later event doesn't publish a head when a former
+ * event isn't done writing. However since we need to deal with NMIs we
+ * cannot fully serialize things.
+ *
+ * What we do is serialize between CPUs so we only have to deal with NMI
+ * nesting on a single CPU.
+ *
+ * We only publish the head (and generate a wakeup) when the outer-most
+ * event completes.
+ */
+static void perf_output_lock(struct perf_output_handle *handle)
+{
+       struct perf_mmap_data *data = handle->data;
+       int cpu;
+
+       handle->locked = 0;
+
+       local_irq_save(handle->flags);
+       cpu = smp_processor_id();
+
+       if (in_nmi() && atomic_read(&data->lock) == cpu)
+               return;
+
+       while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
+               cpu_relax();
+
+       handle->locked = 1;
+}
+
+static void perf_output_unlock(struct perf_output_handle *handle)
+{
+       struct perf_mmap_data *data = handle->data;
+       int head, cpu;
+
+       data->done_head = data->head;
+
+       if (!handle->locked)
+               goto out;
+
+again:
+       /*
+        * The xchg implies a full barrier that ensures all writes are done
+        * before we publish the new head, matched by a rmb() in userspace when
+        * reading this position.
+        */
+       while ((head = atomic_xchg(&data->done_head, 0)))
+               data->user_page->data_head = head;
+
+       /*
+        * NMI can happen here, which means we can miss a done_head update.
+        */
+
+       cpu = atomic_xchg(&data->lock, -1);
+       WARN_ON_ONCE(cpu != smp_processor_id());
+
+       /*
+        * Therefore we have to validate we did not indeed do so.
+        */
+       if (unlikely(atomic_read(&data->done_head))) {
+               /*
+                * Since we had it locked, we can lock it again.
+                */
+               while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
+                       cpu_relax();
+
+               goto again;
+       }
+
+       if (atomic_xchg(&data->wakeup, 0))
+               perf_output_wakeup(handle);
+out:
+       local_irq_restore(handle->flags);
+}
+
+static int perf_output_begin(struct perf_output_handle *handle,
+                            struct perf_counter *counter, unsigned int size,
+                            int nmi, int overflow)
+{
+       struct perf_mmap_data *data;
+       unsigned int offset, head;
+
+       /*
+        * For inherited counters we send all the output towards the parent.
+        */
+       if (counter->parent)
+               counter = counter->parent;
+
+       rcu_read_lock();
+       data = rcu_dereference(counter->data);
+       if (!data)
+               goto out;
+
+       handle->data     = data;
+       handle->counter  = counter;
+       handle->nmi      = nmi;
+       handle->overflow = overflow;
+
+       if (!data->nr_pages)
+               goto fail;
+
+       perf_output_lock(handle);
+
+       do {
+               offset = head = atomic_read(&data->head);
+               head += size;
+       } while (atomic_cmpxchg(&data->head, offset, head) != offset);
+
+       handle->offset  = offset;
+       handle->head    = head;
+
+       if ((offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT))
+               atomic_set(&data->wakeup, 1);
+
+       return 0;
+
+fail:
+       perf_output_wakeup(handle);
+out:
+       rcu_read_unlock();
+
+       return -ENOSPC;
+}
+
+static void perf_output_copy(struct perf_output_handle *handle,
+                            void *buf, unsigned int len)
+{
+       unsigned int pages_mask;
+       unsigned int offset;
+       unsigned int size;
+       void **pages;
+
+       offset          = handle->offset;
+       pages_mask      = handle->data->nr_pages - 1;
+       pages           = handle->data->data_pages;
+
+       do {
+               unsigned int page_offset;
+               int nr;
+
+               nr          = (offset >> PAGE_SHIFT) & pages_mask;
+               page_offset = offset & (PAGE_SIZE - 1);
+               size        = min_t(unsigned int, PAGE_SIZE - page_offset, len);
+
+               memcpy(pages[nr] + page_offset, buf, size);
+
+               len         -= size;
+               buf         += size;
+               offset      += size;
+       } while (len);
+
+       handle->offset = offset;
+
+       /*
+        * Check we didn't copy past our reservation window, taking the
+        * possible unsigned int wrap into account.
+        */
+       WARN_ON_ONCE(((int)(handle->head - handle->offset)) < 0);
+}
+
+#define perf_output_put(handle, x) \
+       perf_output_copy((handle), &(x), sizeof(x))
+
+static void perf_output_end(struct perf_output_handle *handle)
+{
+       struct perf_counter *counter = handle->counter;
+       struct perf_mmap_data *data = handle->data;
+
+       int wakeup_events = counter->hw_event.wakeup_events;
+
+       if (handle->overflow && wakeup_events) {
+               int events = atomic_inc_return(&data->events);
+               if (events >= wakeup_events) {
+                       atomic_sub(wakeup_events, &data->events);
+                       atomic_set(&data->wakeup, 1);
+               }
+       }
+
+       perf_output_unlock(handle);
+       rcu_read_unlock();
+}
+
+static void perf_counter_output(struct perf_counter *counter,
+                               int nmi, struct pt_regs *regs, u64 addr)
+{
+       int ret;
+       u64 record_type = counter->hw_event.record_type;
+       struct perf_output_handle handle;
+       struct perf_event_header header;
+       u64 ip;
+       struct {
+               u32 pid, tid;
+       } tid_entry;
+       struct {
+               u64 event;
+               u64 counter;
+       } group_entry;
+       struct perf_callchain_entry *callchain = NULL;
+       int callchain_size = 0;
+       u64 time;
+       struct {
+               u32 cpu, reserved;
+       } cpu_entry;
+
+       header.type = 0;
+       header.size = sizeof(header);
+
+       header.misc = PERF_EVENT_MISC_OVERFLOW;
+       header.misc |= perf_misc_flags(regs);
+
+       if (record_type & PERF_RECORD_IP) {
+               ip = perf_instruction_pointer(regs);
+               header.type |= PERF_RECORD_IP;
+               header.size += sizeof(ip);
+       }
+
+       if (record_type & PERF_RECORD_TID) {
+               /* namespace issues */
+               tid_entry.pid = current->group_leader->pid;
+               tid_entry.tid = current->pid;
+
+               header.type |= PERF_RECORD_TID;
+               header.size += sizeof(tid_entry);
+       }
+
+       if (record_type & PERF_RECORD_TIME) {
+               /*
+                * Maybe do better on x86 and provide cpu_clock_nmi()
+                */
+               time = sched_clock();
+
+               header.type |= PERF_RECORD_TIME;
+               header.size += sizeof(u64);
+       }
+
+       if (record_type & PERF_RECORD_ADDR) {
+               header.type |= PERF_RECORD_ADDR;
+               header.size += sizeof(u64);
+       }
+
+       if (record_type & PERF_RECORD_CONFIG) {
+               header.type |= PERF_RECORD_CONFIG;
+               header.size += sizeof(u64);
+       }
+
+       if (record_type & PERF_RECORD_CPU) {
+               header.type |= PERF_RECORD_CPU;
+               header.size += sizeof(cpu_entry);
+
+               cpu_entry.cpu = raw_smp_processor_id();
+       }
+
+       if (record_type & PERF_RECORD_GROUP) {
+               header.type |= PERF_RECORD_GROUP;
+               header.size += sizeof(u64) +
+                       counter->nr_siblings * sizeof(group_entry);
+       }
+
+       if (record_type & PERF_RECORD_CALLCHAIN) {
+               callchain = perf_callchain(regs);
+
+               if (callchain) {
+                       callchain_size = (1 + callchain->nr) * sizeof(u64);
+
+                       header.type |= PERF_RECORD_CALLCHAIN;
+                       header.size += callchain_size;
+               }
+       }
+
+       ret = perf_output_begin(&handle, counter, header.size, nmi, 1);
+       if (ret)
+               return;
+
+       perf_output_put(&handle, header);
+
+       if (record_type & PERF_RECORD_IP)
+               perf_output_put(&handle, ip);
+
+       if (record_type & PERF_RECORD_TID)
+               perf_output_put(&handle, tid_entry);
+
+       if (record_type & PERF_RECORD_TIME)
+               perf_output_put(&handle, time);
+
+       if (record_type & PERF_RECORD_ADDR)
+               perf_output_put(&handle, addr);
+
+       if (record_type & PERF_RECORD_CONFIG)
+               perf_output_put(&handle, counter->hw_event.config);
+
+       if (record_type & PERF_RECORD_CPU)
+               perf_output_put(&handle, cpu_entry);
+
+       /*
+        * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.
+        */
+       if (record_type & PERF_RECORD_GROUP) {
+               struct perf_counter *leader, *sub;
+               u64 nr = counter->nr_siblings;
+
+               perf_output_put(&handle, nr);
+
+               leader = counter->group_leader;
+               list_for_each_entry(sub, &leader->sibling_list, list_entry) {
+                       if (sub != counter)
+                               sub->pmu->read(sub);
+
+                       group_entry.event = sub->hw_event.config;
+                       group_entry.counter = atomic64_read(&sub->count);
+
+                       perf_output_put(&handle, group_entry);
+               }
+       }
+
+       if (callchain)
+               perf_output_copy(&handle, callchain, callchain_size);
+
+       perf_output_end(&handle);
+}
+
+/*
+ * comm tracking
+ */
+
+struct perf_comm_event {
+       struct task_struct      *task;
+       char                    *comm;
+       int                     comm_size;
+
+       struct {
+               struct perf_event_header        header;
+
+               u32                             pid;
+               u32                             tid;
+       } event;
+};
+
+static void perf_counter_comm_output(struct perf_counter *counter,
+                                    struct perf_comm_event *comm_event)
+{
+       struct perf_output_handle handle;
+       int size = comm_event->event.header.size;
+       int ret = perf_output_begin(&handle, counter, size, 0, 0);
+
+       if (ret)
+               return;
+
+       perf_output_put(&handle, comm_event->event);
+       perf_output_copy(&handle, comm_event->comm,
+                                  comm_event->comm_size);
+       perf_output_end(&handle);
+}
+
+static int perf_counter_comm_match(struct perf_counter *counter,
+                                  struct perf_comm_event *comm_event)
+{
+       if (counter->hw_event.comm &&
+           comm_event->event.header.type == PERF_EVENT_COMM)
+               return 1;
+
+       return 0;
+}
+
+static void perf_counter_comm_ctx(struct perf_counter_context *ctx,
+                                 struct perf_comm_event *comm_event)
+{
+       struct perf_counter *counter;
+
+       if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
+               return;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
+               if (perf_counter_comm_match(counter, comm_event))
+                       perf_counter_comm_output(counter, comm_event);
+       }
+       rcu_read_unlock();
+}
+
+static void perf_counter_comm_event(struct perf_comm_event *comm_event)
+{
+       struct perf_cpu_context *cpuctx;
+       unsigned int size;
+       char *comm = comm_event->task->comm;
+
+       size = ALIGN(strlen(comm)+1, sizeof(u64));
+
+       comm_event->comm = comm;
+       comm_event->comm_size = size;
+
+       comm_event->event.header.size = sizeof(comm_event->event) + size;
+
+       cpuctx = &get_cpu_var(perf_cpu_context);
+       perf_counter_comm_ctx(&cpuctx->ctx, comm_event);
+       put_cpu_var(perf_cpu_context);
+
+       perf_counter_comm_ctx(&current->perf_counter_ctx, comm_event);
 }
 
-static ssize_t
-perf_copy_usrdata(struct perf_data *usrdata, char __user *buf, size_t count)
+void perf_counter_comm(struct task_struct *task)
 {
-       if (!usrdata->len)
-               return 0;
-
-       count = min(count, (size_t)usrdata->len);
-       if (copy_to_user(buf, usrdata->data + usrdata->rd_idx, count))
-               return -EFAULT;
+       struct perf_comm_event comm_event;
 
-       /* Adjust the counters */
-       usrdata->len -= count;
-       if (!usrdata->len)
-               usrdata->rd_idx = 0;
-       else
-               usrdata->rd_idx += count;
+       if (!atomic_read(&nr_comm_tracking))
+               return;
+       
+       comm_event = (struct perf_comm_event){
+               .task   = task,
+               .event  = {
+                       .header = { .type = PERF_EVENT_COMM, },
+                       .pid    = task->group_leader->pid,
+                       .tid    = task->pid,
+               },
+       };
 
-       return count;
+       perf_counter_comm_event(&comm_event);
 }
 
-static ssize_t
-perf_read_irq_data(struct perf_counter *counter,
-                  char __user          *buf,
-                  size_t               count,
-                  int                  nonblocking)
-{
-       struct perf_data *irqdata, *usrdata;
-       DECLARE_WAITQUEUE(wait, current);
-       ssize_t res, res2;
+/*
+ * mmap tracking
+ */
 
-       irqdata = counter->irqdata;
-       usrdata = counter->usrdata;
+struct perf_mmap_event {
+       struct file     *file;
+       char            *file_name;
+       int             file_size;
 
-       if (usrdata->len + irqdata->len >= count)
-               goto read_pending;
+       struct {
+               struct perf_event_header        header;
 
-       if (nonblocking)
-               return -EAGAIN;
+               u32                             pid;
+               u32                             tid;
+               u64                             start;
+               u64                             len;
+               u64                             pgoff;
+       } event;
+};
 
-       spin_lock_irq(&counter->waitq.lock);
-       __add_wait_queue(&counter->waitq, &wait);
-       for (;;) {
-               set_current_state(TASK_INTERRUPTIBLE);
-               if (usrdata->len + irqdata->len >= count)
-                       break;
+static void perf_counter_mmap_output(struct perf_counter *counter,
+                                    struct perf_mmap_event *mmap_event)
+{
+       struct perf_output_handle handle;
+       int size = mmap_event->event.header.size;
+       int ret = perf_output_begin(&handle, counter, size, 0, 0);
 
-               if (signal_pending(current))
-                       break;
+       if (ret)
+               return;
 
-               if (counter->state == PERF_COUNTER_STATE_ERROR)
-                       break;
+       perf_output_put(&handle, mmap_event->event);
+       perf_output_copy(&handle, mmap_event->file_name,
+                                  mmap_event->file_size);
+       perf_output_end(&handle);
+}
 
-               spin_unlock_irq(&counter->waitq.lock);
-               schedule();
-               spin_lock_irq(&counter->waitq.lock);
-       }
-       __remove_wait_queue(&counter->waitq, &wait);
-       __set_current_state(TASK_RUNNING);
-       spin_unlock_irq(&counter->waitq.lock);
+static int perf_counter_mmap_match(struct perf_counter *counter,
+                                  struct perf_mmap_event *mmap_event)
+{
+       if (counter->hw_event.mmap &&
+           mmap_event->event.header.type == PERF_EVENT_MMAP)
+               return 1;
 
-       if (usrdata->len + irqdata->len < count &&
-           counter->state != PERF_COUNTER_STATE_ERROR)
-               return -ERESTARTSYS;
-read_pending:
-       mutex_lock(&counter->mutex);
+       if (counter->hw_event.munmap &&
+           mmap_event->event.header.type == PERF_EVENT_MUNMAP)
+               return 1;
 
-       /* Drain pending data first: */
-       res = perf_copy_usrdata(usrdata, buf, count);
-       if (res < 0 || res == count)
-               goto out;
+       return 0;
+}
+
+static void perf_counter_mmap_ctx(struct perf_counter_context *ctx,
+                                 struct perf_mmap_event *mmap_event)
+{
+       struct perf_counter *counter;
+
+       if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
+               return;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
+               if (perf_counter_mmap_match(counter, mmap_event))
+                       perf_counter_mmap_output(counter, mmap_event);
+       }
+       rcu_read_unlock();
+}
 
-       /* Switch irq buffer: */
-       usrdata = perf_switch_irq_data(counter);
-       res2 = perf_copy_usrdata(usrdata, buf + res, count - res);
-       if (res2 < 0) {
-               if (!res)
-                       res = -EFAULT;
+static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
+{
+       struct perf_cpu_context *cpuctx;
+       struct file *file = mmap_event->file;
+       unsigned int size;
+       char tmp[16];
+       char *buf = NULL;
+       char *name;
+
+       if (file) {
+               buf = kzalloc(PATH_MAX, GFP_KERNEL);
+               if (!buf) {
+                       name = strncpy(tmp, "//enomem", sizeof(tmp));
+                       goto got_name;
+               }
+               name = d_path(&file->f_path, buf, PATH_MAX);
+               if (IS_ERR(name)) {
+                       name = strncpy(tmp, "//toolong", sizeof(tmp));
+                       goto got_name;
+               }
        } else {
-               res += res2;
+               name = strncpy(tmp, "//anon", sizeof(tmp));
+               goto got_name;
        }
-out:
-       mutex_unlock(&counter->mutex);
 
-       return res;
+got_name:
+       size = ALIGN(strlen(name)+1, sizeof(u64));
+
+       mmap_event->file_name = name;
+       mmap_event->file_size = size;
+
+       mmap_event->event.header.size = sizeof(mmap_event->event) + size;
+
+       cpuctx = &get_cpu_var(perf_cpu_context);
+       perf_counter_mmap_ctx(&cpuctx->ctx, mmap_event);
+       put_cpu_var(perf_cpu_context);
+
+       perf_counter_mmap_ctx(&current->perf_counter_ctx, mmap_event);
+
+       kfree(buf);
 }
 
-static ssize_t
-perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+void perf_counter_mmap(unsigned long addr, unsigned long len,
+                      unsigned long pgoff, struct file *file)
 {
-       struct perf_counter *counter = file->private_data;
+       struct perf_mmap_event mmap_event;
 
-       switch (counter->hw_event.record_type) {
-       case PERF_RECORD_SIMPLE:
-               return perf_read_hw(counter, buf, count);
+       if (!atomic_read(&nr_mmap_tracking))
+               return;
 
-       case PERF_RECORD_IRQ:
-       case PERF_RECORD_GROUP:
-               return perf_read_irq_data(counter, buf, count,
-                                         file->f_flags & O_NONBLOCK);
-       }
-       return -EINVAL;
+       mmap_event = (struct perf_mmap_event){
+               .file   = file,
+               .event  = {
+                       .header = { .type = PERF_EVENT_MMAP, },
+                       .pid    = current->group_leader->pid,
+                       .tid    = current->pid,
+                       .start  = addr,
+                       .len    = len,
+                       .pgoff  = pgoff,
+               },
+       };
+
+       perf_counter_mmap_event(&mmap_event);
 }
 
-static unsigned int perf_poll(struct file *file, poll_table *wait)
+void perf_counter_munmap(unsigned long addr, unsigned long len,
+                        unsigned long pgoff, struct file *file)
 {
-       struct perf_counter *counter = file->private_data;
-       unsigned int events = 0;
-       unsigned long flags;
+       struct perf_mmap_event mmap_event;
 
-       poll_wait(file, &counter->waitq, wait);
+       if (!atomic_read(&nr_munmap_tracking))
+               return;
 
-       spin_lock_irqsave(&counter->waitq.lock, flags);
-       if (counter->usrdata->len || counter->irqdata->len)
-               events |= POLLIN;
-       spin_unlock_irqrestore(&counter->waitq.lock, flags);
+       mmap_event = (struct perf_mmap_event){
+               .file   = file,
+               .event  = {
+                       .header = { .type = PERF_EVENT_MUNMAP, },
+                       .pid    = current->group_leader->pid,
+                       .tid    = current->pid,
+                       .start  = addr,
+                       .len    = len,
+                       .pgoff  = pgoff,
+               },
+       };
 
-       return events;
+       perf_counter_mmap_event(&mmap_event);
 }
 
-static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+/*
+ * Generic counter overflow handling.
+ */
+
+int perf_counter_overflow(struct perf_counter *counter,
+                         int nmi, struct pt_regs *regs, u64 addr)
 {
-       struct perf_counter *counter = file->private_data;
-       int err = 0;
+       int events = atomic_read(&counter->event_limit);
+       int ret = 0;
 
-       switch (cmd) {
-       case PERF_COUNTER_IOC_ENABLE:
-               perf_counter_enable_family(counter);
-               break;
-       case PERF_COUNTER_IOC_DISABLE:
-               perf_counter_disable_family(counter);
-               break;
-       default:
-               err = -ENOTTY;
+       counter->hw.interrupts++;
+
+       /*
+        * XXX event_limit might not quite work as expected on inherited
+        * counters
+        */
+
+       counter->pending_kill = POLL_IN;
+       if (events && atomic_dec_and_test(&counter->event_limit)) {
+               ret = 1;
+               counter->pending_kill = POLL_HUP;
+               if (nmi) {
+                       counter->pending_disable = 1;
+                       perf_pending_queue(&counter->pending,
+                                          perf_pending_counter);
+               } else
+                       perf_counter_disable(counter);
        }
-       return err;
-}
 
-static const struct file_operations perf_fops = {
-       .release                = perf_release,
-       .read                   = perf_read,
-       .poll                   = perf_poll,
-       .unlocked_ioctl         = perf_ioctl,
-       .compat_ioctl           = perf_ioctl,
-};
+       perf_counter_output(counter, nmi, regs, addr);
+       return ret;
+}
 
 /*
  * Generic software counter infrastructure
@@ -1382,67 +2481,15 @@ static void perf_swcounter_set_period(struct perf_counter *counter)
        atomic64_set(&hwc->count, -left);
 }
 
-static void perf_swcounter_save_and_restart(struct perf_counter *counter)
-{
-       perf_swcounter_update(counter);
-       perf_swcounter_set_period(counter);
-}
-
-static void perf_swcounter_store_irq(struct perf_counter *counter, u64 data)
-{
-       struct perf_data *irqdata = counter->irqdata;
-
-       if (irqdata->len > PERF_DATA_BUFLEN - sizeof(u64)) {
-               irqdata->overrun++;
-       } else {
-               u64 *p = (u64 *) &irqdata->data[irqdata->len];
-
-               *p = data;
-               irqdata->len += sizeof(u64);
-       }
-}
-
-static void perf_swcounter_handle_group(struct perf_counter *sibling)
-{
-       struct perf_counter *counter, *group_leader = sibling->group_leader;
-
-       list_for_each_entry(counter, &group_leader->sibling_list, list_entry) {
-               counter->hw_ops->read(counter);
-               perf_swcounter_store_irq(sibling, counter->hw_event.type);
-               perf_swcounter_store_irq(sibling, atomic64_read(&counter->count));
-       }
-}
-
-static void perf_swcounter_interrupt(struct perf_counter *counter,
-                                    int nmi, struct pt_regs *regs)
-{
-       switch (counter->hw_event.record_type) {
-       case PERF_RECORD_SIMPLE:
-               break;
-
-       case PERF_RECORD_IRQ:
-               perf_swcounter_store_irq(counter, instruction_pointer(regs));
-               break;
-
-       case PERF_RECORD_GROUP:
-               perf_swcounter_handle_group(counter);
-               break;
-       }
-
-       if (nmi) {
-               counter->wakeup_pending = 1;
-               set_tsk_thread_flag(current, TIF_PERF_COUNTERS);
-       } else
-               wake_up(&counter->waitq);
-}
-
 static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
 {
+       enum hrtimer_restart ret = HRTIMER_RESTART;
        struct perf_counter *counter;
        struct pt_regs *regs;
+       u64 period;
 
        counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
-       counter->hw_ops->read(counter);
+       counter->pmu->read(counter);
 
        regs = get_irq_regs();
        /*
@@ -1453,32 +2500,42 @@ static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
                        !counter->hw_event.exclude_user)
                regs = task_pt_regs(current);
 
-       if (regs)
-               perf_swcounter_interrupt(counter, 0, regs);
+       if (regs) {
+               if (perf_counter_overflow(counter, 0, regs, 0))
+                       ret = HRTIMER_NORESTART;
+       }
 
-       hrtimer_forward_now(hrtimer, ns_to_ktime(counter->hw.irq_period));
+       period = max_t(u64, 10000, counter->hw.irq_period);
+       hrtimer_forward_now(hrtimer, ns_to_ktime(period));
 
-       return HRTIMER_RESTART;
+       return ret;
 }
 
 static void perf_swcounter_overflow(struct perf_counter *counter,
-                                   int nmi, struct pt_regs *regs)
+                                   int nmi, struct pt_regs *regs, u64 addr)
 {
-       perf_swcounter_save_and_restart(counter);
-       perf_swcounter_interrupt(counter, nmi, regs);
+       perf_swcounter_update(counter);
+       perf_swcounter_set_period(counter);
+       if (perf_counter_overflow(counter, nmi, regs, addr))
+               /* soft-disable the counter */
+               ;
+
 }
 
 static int perf_swcounter_match(struct perf_counter *counter,
-                               enum hw_event_types event,
-                               struct pt_regs *regs)
+                               enum perf_event_types type,
+                               u32 event, struct pt_regs *regs)
 {
        if (counter->state != PERF_COUNTER_STATE_ACTIVE)
                return 0;
 
-       if (counter->hw_event.raw)
+       if (perf_event_raw(&counter->hw_event))
+               return 0;
+
+       if (perf_event_type(&counter->hw_event) != type)
                return 0;
 
-       if (counter->hw_event.type != event)
+       if (perf_event_id(&counter->hw_event) != event)
                return 0;
 
        if (counter->hw_event.exclude_user && user_mode(regs))
@@ -1491,42 +2548,78 @@ static int perf_swcounter_match(struct perf_counter *counter,
 }
 
 static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
-                              int nmi, struct pt_regs *regs)
+                              int nmi, struct pt_regs *regs, u64 addr)
 {
        int neg = atomic64_add_negative(nr, &counter->hw.count);
        if (counter->hw.irq_period && !neg)
-               perf_swcounter_overflow(counter, nmi, regs);
+               perf_swcounter_overflow(counter, nmi, regs, addr);
 }
 
 static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
-                                    enum hw_event_types event, u64 nr,
-                                    int nmi, struct pt_regs *regs)
+                                    enum perf_event_types type, u32 event,
+                                    u64 nr, int nmi, struct pt_regs *regs,
+                                    u64 addr)
 {
        struct perf_counter *counter;
 
-       if (list_empty(&ctx->event_list))
+       if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
                return;
 
        rcu_read_lock();
        list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
-               if (perf_swcounter_match(counter, event, regs))
-                       perf_swcounter_add(counter, nr, nmi, regs);
+               if (perf_swcounter_match(counter, type, event, regs))
+                       perf_swcounter_add(counter, nr, nmi, regs, addr);
        }
        rcu_read_unlock();
 }
 
-void perf_swcounter_event(enum hw_event_types event, u64 nr,
-                         int nmi, struct pt_regs *regs)
+static int *perf_swcounter_recursion_context(struct perf_cpu_context *cpuctx)
+{
+       if (in_nmi())
+               return &cpuctx->recursion[3];
+
+       if (in_irq())
+               return &cpuctx->recursion[2];
+
+       if (in_softirq())
+               return &cpuctx->recursion[1];
+
+       return &cpuctx->recursion[0];
+}
+
+static void __perf_swcounter_event(enum perf_event_types type, u32 event,
+                                  u64 nr, int nmi, struct pt_regs *regs,
+                                  u64 addr)
 {
        struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
+       int *recursion = perf_swcounter_recursion_context(cpuctx);
+
+       if (*recursion)
+               goto out;
+
+       (*recursion)++;
+       barrier();
 
-       perf_swcounter_ctx_event(&cpuctx->ctx, event, nr, nmi, regs);
-       if (cpuctx->task_ctx)
-               perf_swcounter_ctx_event(cpuctx->task_ctx, event, nr, nmi, regs);
+       perf_swcounter_ctx_event(&cpuctx->ctx, type, event,
+                                nr, nmi, regs, addr);
+       if (cpuctx->task_ctx) {
+               perf_swcounter_ctx_event(cpuctx->task_ctx, type, event,
+                                        nr, nmi, regs, addr);
+       }
+
+       barrier();
+       (*recursion)--;
 
+out:
        put_cpu_var(perf_cpu_context);
 }
 
+void
+perf_swcounter_event(u32 event, u64 nr, int nmi, struct pt_regs *regs, u64 addr)
+{
+       __perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi, regs, addr);
+}
+
 static void perf_swcounter_read(struct perf_counter *counter)
 {
        perf_swcounter_update(counter);
@@ -1543,7 +2636,7 @@ static void perf_swcounter_disable(struct perf_counter *counter)
        perf_swcounter_update(counter);
 }
 
-static const struct hw_perf_counter_ops perf_ops_generic = {
+static const struct pmu perf_ops_generic = {
        .enable         = perf_swcounter_enable,
        .disable        = perf_swcounter_disable,
        .read           = perf_swcounter_read,
@@ -1574,8 +2667,9 @@ static int cpu_clock_perf_counter_enable(struct perf_counter *counter)
        hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        hwc->hrtimer.function = perf_swcounter_hrtimer;
        if (hwc->irq_period) {
+               u64 period = max_t(u64, 10000, hwc->irq_period);
                __hrtimer_start_range_ns(&hwc->hrtimer,
-                               ns_to_ktime(hwc->irq_period), 0,
+                               ns_to_ktime(period), 0,
                                HRTIMER_MODE_REL, 0);
        }
 
@@ -1593,7 +2687,7 @@ static void cpu_clock_perf_counter_read(struct perf_counter *counter)
        cpu_clock_perf_counter_update(counter);
 }
 
-static const struct hw_perf_counter_ops perf_ops_cpu_clock = {
+static const struct pmu perf_ops_cpu_clock = {
        .enable         = cpu_clock_perf_counter_enable,
        .disable        = cpu_clock_perf_counter_disable,
        .read           = cpu_clock_perf_counter_read,
@@ -1603,43 +2697,30 @@ static const struct hw_perf_counter_ops perf_ops_cpu_clock = {
  * Software counter: task time clock
  */
 
-/*
- * Called from within the scheduler:
- */
-static u64 task_clock_perf_counter_val(struct perf_counter *counter, int update)
-{
-       struct task_struct *curr = counter->task;
-       u64 delta;
-
-       delta = __task_delta_exec(curr, update);
-
-       return curr->se.sum_exec_runtime + delta;
-}
-
 static void task_clock_perf_counter_update(struct perf_counter *counter, u64 now)
 {
        u64 prev;
        s64 delta;
 
-       prev = atomic64_read(&counter->hw.prev_count);
-
-       atomic64_set(&counter->hw.prev_count, now);
-
+       prev = atomic64_xchg(&counter->hw.prev_count, now);
        delta = now - prev;
-
        atomic64_add(delta, &counter->count);
 }
 
 static int task_clock_perf_counter_enable(struct perf_counter *counter)
 {
        struct hw_perf_counter *hwc = &counter->hw;
+       u64 now;
+
+       now = counter->ctx->time;
 
-       atomic64_set(&hwc->prev_count, task_clock_perf_counter_val(counter, 0));
+       atomic64_set(&hwc->prev_count, now);
        hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        hwc->hrtimer.function = perf_swcounter_hrtimer;
        if (hwc->irq_period) {
+               u64 period = max_t(u64, 10000, hwc->irq_period);
                __hrtimer_start_range_ns(&hwc->hrtimer,
-                               ns_to_ktime(hwc->irq_period), 0,
+                               ns_to_ktime(period), 0,
                                HRTIMER_MODE_REL, 0);
        }
 
@@ -1649,74 +2730,32 @@ static int task_clock_perf_counter_enable(struct perf_counter *counter)
 static void task_clock_perf_counter_disable(struct perf_counter *counter)
 {
        hrtimer_cancel(&counter->hw.hrtimer);
-       task_clock_perf_counter_update(counter,
-                       task_clock_perf_counter_val(counter, 0));
+       task_clock_perf_counter_update(counter, counter->ctx->time);
+
 }
 
 static void task_clock_perf_counter_read(struct perf_counter *counter)
 {
-       task_clock_perf_counter_update(counter,
-                       task_clock_perf_counter_val(counter, 1));
+       u64 time;
+
+       if (!in_nmi()) {
+               update_context_time(counter->ctx);
+               time = counter->ctx->time;
+       } else {
+               u64 now = perf_clock();
+               u64 delta = now - counter->ctx->timestamp;
+               time = counter->ctx->time + delta;
+       }
+
+       task_clock_perf_counter_update(counter, time);
 }
 
-static const struct hw_perf_counter_ops perf_ops_task_clock = {
+static const struct pmu perf_ops_task_clock = {
        .enable         = task_clock_perf_counter_enable,
        .disable        = task_clock_perf_counter_disable,
        .read           = task_clock_perf_counter_read,
 };
 
-/*
- * Software counter: context switches
- */
-
-static u64 get_context_switches(struct perf_counter *counter)
-{
-       struct task_struct *curr = counter->ctx->task;
-
-       if (curr)
-               return curr->nvcsw + curr->nivcsw;
-       return cpu_nr_switches(smp_processor_id());
-}
-
-static void context_switches_perf_counter_update(struct perf_counter *counter)
-{
-       u64 prev, now;
-       s64 delta;
-
-       prev = atomic64_read(&counter->hw.prev_count);
-       now = get_context_switches(counter);
-
-       atomic64_set(&counter->hw.prev_count, now);
-
-       delta = now - prev;
-
-       atomic64_add(delta, &counter->count);
-}
-
-static void context_switches_perf_counter_read(struct perf_counter *counter)
-{
-       context_switches_perf_counter_update(counter);
-}
-
-static int context_switches_perf_counter_enable(struct perf_counter *counter)
-{
-       if (counter->prev_state <= PERF_COUNTER_STATE_OFF)
-               atomic64_set(&counter->hw.prev_count,
-                            get_context_switches(counter));
-       return 0;
-}
-
-static void context_switches_perf_counter_disable(struct perf_counter *counter)
-{
-       context_switches_perf_counter_update(counter);
-}
-
-static const struct hw_perf_counter_ops perf_ops_context_switches = {
-       .enable         = context_switches_perf_counter_enable,
-       .disable        = context_switches_perf_counter_disable,
-       .read           = context_switches_perf_counter_read,
-};
-
 /*
  * Software counter: cpu migrations
  */
@@ -1763,18 +2802,56 @@ static void cpu_migrations_perf_counter_disable(struct perf_counter *counter)
        cpu_migrations_perf_counter_update(counter);
 }
 
-static const struct hw_perf_counter_ops perf_ops_cpu_migrations = {
+static const struct pmu perf_ops_cpu_migrations = {
        .enable         = cpu_migrations_perf_counter_enable,
        .disable        = cpu_migrations_perf_counter_disable,
        .read           = cpu_migrations_perf_counter_read,
 };
 
-static const struct hw_perf_counter_ops *
-sw_perf_counter_init(struct perf_counter *counter)
+#ifdef CONFIG_EVENT_PROFILE
+void perf_tpcounter_event(int event_id)
 {
-       struct perf_counter_hw_event *hw_event = &counter->hw_event;
-       const struct hw_perf_counter_ops *hw_ops = NULL;
-       struct hw_perf_counter *hwc = &counter->hw;
+       struct pt_regs *regs = get_irq_regs();
+
+       if (!regs)
+               regs = task_pt_regs(current);
+
+       __perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, 1, 1, regs, 0);
+}
+EXPORT_SYMBOL_GPL(perf_tpcounter_event);
+
+extern int ftrace_profile_enable(int);
+extern void ftrace_profile_disable(int);
+
+static void tp_perf_counter_destroy(struct perf_counter *counter)
+{
+       ftrace_profile_disable(perf_event_id(&counter->hw_event));
+}
+
+static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
+{
+       int event_id = perf_event_id(&counter->hw_event);
+       int ret;
+
+       ret = ftrace_profile_enable(event_id);
+       if (ret)
+               return NULL;
+
+       counter->destroy = tp_perf_counter_destroy;
+       counter->hw.irq_period = counter->hw_event.irq_period;
+
+       return &perf_ops_generic;
+}
+#else
+static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
+{
+       return NULL;
+}
+#endif
+
+static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
+{
+       const struct pmu *pmu = NULL;
 
        /*
         * Software counters (currently) can't in general distinguish
@@ -1783,12 +2860,10 @@ sw_perf_counter_init(struct perf_counter *counter)
         * to be kernel events, and page faults are never hypervisor
         * events.
         */
-       switch (counter->hw_event.type) {
+       switch (perf_event_id(&counter->hw_event)) {
        case PERF_COUNT_CPU_CLOCK:
-               hw_ops = &perf_ops_cpu_clock;
+               pmu = &perf_ops_cpu_clock;
 
-               if (hw_event->irq_period && hw_event->irq_period < 10000)
-                       hw_event->irq_period = 10000;
                break;
        case PERF_COUNT_TASK_CLOCK:
                /*
@@ -1796,34 +2871,24 @@ sw_perf_counter_init(struct perf_counter *counter)
                 * use the cpu_clock counter instead.
                 */
                if (counter->ctx->task)
-                       hw_ops = &perf_ops_task_clock;
+                       pmu = &perf_ops_task_clock;
                else
-                       hw_ops = &perf_ops_cpu_clock;
+                       pmu = &perf_ops_cpu_clock;
 
-               if (hw_event->irq_period && hw_event->irq_period < 10000)
-                       hw_event->irq_period = 10000;
                break;
        case PERF_COUNT_PAGE_FAULTS:
        case PERF_COUNT_PAGE_FAULTS_MIN:
        case PERF_COUNT_PAGE_FAULTS_MAJ:
-               hw_ops = &perf_ops_generic;
-               break;
        case PERF_COUNT_CONTEXT_SWITCHES:
-               if (!counter->hw_event.exclude_kernel)
-                       hw_ops = &perf_ops_context_switches;
+               pmu = &perf_ops_generic;
                break;
        case PERF_COUNT_CPU_MIGRATIONS:
                if (!counter->hw_event.exclude_kernel)
-                       hw_ops = &perf_ops_cpu_migrations;
-               break;
-       default:
+                       pmu = &perf_ops_cpu_migrations;
                break;
        }
 
-       if (hw_ops)
-               hwc->irq_period = hw_event->irq_period;
-
-       return hw_ops;
+       return pmu;
 }
 
 /*
@@ -1836,12 +2901,14 @@ perf_counter_alloc(struct perf_counter_hw_event *hw_event,
                   struct perf_counter *group_leader,
                   gfp_t gfpflags)
 {
-       const struct hw_perf_counter_ops *hw_ops;
+       const struct pmu *pmu;
        struct perf_counter *counter;
+       struct hw_perf_counter *hwc;
+       long err;
 
        counter = kzalloc(sizeof(*counter), gfpflags);
        if (!counter)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
 
        /*
         * Single counters are their own group leaders, with an
@@ -1856,32 +2923,73 @@ perf_counter_alloc(struct perf_counter_hw_event *hw_event,
        INIT_LIST_HEAD(&counter->sibling_list);
        init_waitqueue_head(&counter->waitq);
 
+       mutex_init(&counter->mmap_mutex);
+
        INIT_LIST_HEAD(&counter->child_list);
 
-       counter->irqdata                = &counter->data[0];
-       counter->usrdata                = &counter->data[1];
        counter->cpu                    = cpu;
        counter->hw_event               = *hw_event;
-       counter->wakeup_pending         = 0;
        counter->group_leader           = group_leader;
-       counter->hw_ops                 = NULL;
+       counter->pmu                    = NULL;
        counter->ctx                    = ctx;
 
        counter->state = PERF_COUNTER_STATE_INACTIVE;
        if (hw_event->disabled)
                counter->state = PERF_COUNTER_STATE_OFF;
 
-       hw_ops = NULL;
-       if (!hw_event->raw && hw_event->type < 0)
-               hw_ops = sw_perf_counter_init(counter);
+       pmu = NULL;
+
+       hwc = &counter->hw;
+       if (hw_event->freq && hw_event->irq_freq)
+               hwc->irq_period = div64_u64(TICK_NSEC, hw_event->irq_freq);
        else
-               hw_ops = hw_perf_counter_init(counter);
+               hwc->irq_period = hw_event->irq_period;
+
+       /*
+        * we currently do not support PERF_RECORD_GROUP on inherited counters
+        */
+       if (hw_event->inherit && (hw_event->record_type & PERF_RECORD_GROUP))
+               goto done;
+
+       if (perf_event_raw(hw_event)) {
+               pmu = hw_perf_counter_init(counter);
+               goto done;
+       }
+
+       switch (perf_event_type(hw_event)) {
+       case PERF_TYPE_HARDWARE:
+               pmu = hw_perf_counter_init(counter);
+               break;
+
+       case PERF_TYPE_SOFTWARE:
+               pmu = sw_perf_counter_init(counter);
+               break;
+
+       case PERF_TYPE_TRACEPOINT:
+               pmu = tp_perf_counter_init(counter);
+               break;
+       }
+done:
+       err = 0;
+       if (!pmu)
+               err = -EINVAL;
+       else if (IS_ERR(pmu))
+               err = PTR_ERR(pmu);
 
-       if (!hw_ops) {
+       if (err) {
                kfree(counter);
-               return NULL;
+               return ERR_PTR(err);
        }
-       counter->hw_ops = hw_ops;
+
+       counter->pmu = pmu;
+
+       atomic_inc(&nr_counters);
+       if (counter->hw_event.mmap)
+               atomic_inc(&nr_mmap_tracking);
+       if (counter->hw_event.munmap)
+               atomic_inc(&nr_munmap_tracking);
+       if (counter->hw_event.comm)
+               atomic_inc(&nr_comm_tracking);
 
        return counter;
 }
@@ -1953,10 +3061,10 @@ SYSCALL_DEFINE5(perf_counter_open,
                        goto err_put_context;
        }
 
-       ret = -EINVAL;
        counter = perf_counter_alloc(&hw_event, cpu, ctx, group_leader,
                                     GFP_KERNEL);
-       if (!counter)
+       ret = PTR_ERR(counter);
+       if (IS_ERR(counter))
                goto err_put_context;
 
        ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0);
@@ -2028,15 +3136,14 @@ inherit_counter(struct perf_counter *parent_counter,
        child_counter = perf_counter_alloc(&parent_counter->hw_event,
                                           parent_counter->cpu, child_ctx,
                                           group_leader, GFP_KERNEL);
-       if (!child_counter)
-               return NULL;
+       if (IS_ERR(child_counter))
+               return child_counter;
 
        /*
         * Link it up in the child's context:
         */
        child_counter->task = child;
-       list_add_counter(child_counter, child_ctx);
-       child_ctx->nr_counters++;
+       add_counter_to_ctx(child_counter, child_ctx);
 
        child_counter->parent = parent_counter;
        /*
@@ -2081,15 +3188,17 @@ static int inherit_group(struct perf_counter *parent_counter,
 {
        struct perf_counter *leader;
        struct perf_counter *sub;
+       struct perf_counter *child_ctr;
 
        leader = inherit_counter(parent_counter, parent, parent_ctx,
                                 child, NULL, child_ctx);
-       if (!leader)
-               return -ENOMEM;
+       if (IS_ERR(leader))
+               return PTR_ERR(leader);
        list_for_each_entry(sub, &parent_counter->sibling_list, list_entry) {
-               if (!inherit_counter(sub, parent, parent_ctx,
-                                    child, leader, child_ctx))
-                       return -ENOMEM;
+               child_ctr = inherit_counter(sub, parent, parent_ctx,
+                                           child, leader, child_ctx);
+               if (IS_ERR(child_ctr))
+                       return PTR_ERR(child_ctr);
        }
        return 0;
 }
@@ -2097,15 +3206,18 @@ static int inherit_group(struct perf_counter *parent_counter,
 static void sync_child_counter(struct perf_counter *child_counter,
                               struct perf_counter *parent_counter)
 {
-       u64 parent_val, child_val;
+       u64 child_val;
 
-       parent_val = atomic64_read(&parent_counter->count);
        child_val = atomic64_read(&child_counter->count);
 
        /*
         * Add back the child's count to the parent's count:
         */
        atomic64_add(child_val, &parent_counter->count);
+       atomic64_add(child_counter->total_time_enabled,
+                    &parent_counter->child_total_time_enabled);
+       atomic64_add(child_counter->total_time_running,
+                    &parent_counter->child_total_time_running);
 
        /*
         * Remove this counter from the parent's list
@@ -2127,7 +3239,6 @@ __perf_counter_exit_task(struct task_struct *child,
                         struct perf_counter_context *child_ctx)
 {
        struct perf_counter *parent_counter;
-       struct perf_counter *sub, *tmp;
 
        /*
         * If we do not self-reap then we have to wait for the
@@ -2139,11 +3250,11 @@ __perf_counter_exit_task(struct task_struct *child,
         */
        if (child != current) {
                wait_task_inactive(child, 0);
-               list_del_init(&child_counter->list_entry);
+               update_counter_times(child_counter);
+               list_del_counter(child_counter, child_ctx);
        } else {
                struct perf_cpu_context *cpuctx;
                unsigned long flags;
-               u64 perf_flags;
 
                /*
                 * Disable and unlink this counter.
@@ -2151,19 +3262,18 @@ __perf_counter_exit_task(struct task_struct *child,
                 * Be careful about zapping the list - IRQ/NMI context
                 * could still be processing it:
                 */
-               curr_rq_lock_irq_save(&flags);
-               perf_flags = hw_perf_save_disable();
+               local_irq_save(flags);
+               perf_disable();
 
                cpuctx = &__get_cpu_var(perf_cpu_context);
 
                group_sched_out(child_counter, cpuctx, child_ctx);
+               update_counter_times(child_counter);
 
-               list_del_init(&child_counter->list_entry);
+               list_del_counter(child_counter, child_ctx);
 
-               child_ctx->nr_counters--;
-
-               hw_perf_restore(perf_flags);
-               curr_rq_unlock_irq_restore(&flags);
+               perf_enable();
+               local_irq_restore(flags);
        }
 
        parent_counter = child_counter->parent;
@@ -2174,14 +3284,7 @@ __perf_counter_exit_task(struct task_struct *child,
         */
        if (parent_counter) {
                sync_child_counter(child_counter, parent_counter);
-               list_for_each_entry_safe(sub, tmp, &child_counter->sibling_list,
-                                        list_entry) {
-                       if (sub->parent) {
-                               sync_child_counter(sub, sub->parent);
-                               kfree(sub);
-                       }
-               }
-               kfree(child_counter);
+               free_counter(child_counter);
        }
 }
 
@@ -2196,14 +3299,25 @@ void perf_counter_exit_task(struct task_struct *child)
        struct perf_counter *child_counter, *tmp;
        struct perf_counter_context *child_ctx;
 
+       WARN_ON_ONCE(child != current);
+
        child_ctx = &child->perf_counter_ctx;
 
        if (likely(!child_ctx->nr_counters))
                return;
 
+again:
        list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list,
                                 list_entry)
                __perf_counter_exit_task(child, child_counter, child_ctx);
+
+       /*
+        * If the last counter was a group counter, it will have appended all
+        * its siblings to the list, but we obtained 'tmp' before that which
+        * will still point to the list head terminating the iteration.
+        */
+       if (!list_empty(&child_ctx->counter_list))
+               goto again;
 }
 
 /*
@@ -2257,9 +3371,9 @@ static void __cpuinit perf_counter_init_cpu(int cpu)
        cpuctx = &per_cpu(perf_cpu_context, cpu);
        __perf_counter_init_context(&cpuctx->ctx, NULL);
 
-       mutex_lock(&perf_resource_mutex);
+       spin_lock(&perf_resource_lock);
        cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu;
-       mutex_unlock(&perf_resource_mutex);
+       spin_unlock(&perf_resource_lock);
 
        hw_perf_counter_setup(cpu);
 }
@@ -2315,15 +3429,12 @@ static struct notifier_block __cpuinitdata perf_cpu_nb = {
        .notifier_call          = perf_cpu_notify,
 };
 
-static int __init perf_counter_init(void)
+void __init perf_counter_init(void)
 {
        perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
                        (void *)(long)smp_processor_id());
        register_cpu_notifier(&perf_cpu_nb);
-
-       return 0;
 }
-early_initcall(perf_counter_init);
 
 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
 {
@@ -2345,7 +3456,7 @@ perf_set_reserve_percpu(struct sysdev_class *class,
        if (val > perf_max_counters)
                return -EINVAL;
 
-       mutex_lock(&perf_resource_mutex);
+       spin_lock(&perf_resource_lock);
        perf_reserved_percpu = val;
        for_each_online_cpu(cpu) {
                cpuctx = &per_cpu(perf_cpu_context, cpu);
@@ -2355,7 +3466,7 @@ perf_set_reserve_percpu(struct sysdev_class *class,
                cpuctx->max_pertask = mpt;
                spin_unlock_irq(&cpuctx->ctx.lock);
        }
-       mutex_unlock(&perf_resource_mutex);
+       spin_unlock(&perf_resource_lock);
 
        return count;
 }
@@ -2377,9 +3488,9 @@ perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
        if (val > 1)
                return -EINVAL;
 
-       mutex_lock(&perf_resource_mutex);
+       spin_lock(&perf_resource_lock);
        perf_overcommit = val;
-       mutex_unlock(&perf_resource_mutex);
+       spin_unlock(&perf_resource_lock);
 
        return count;
 }