Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (123 commits)
  perf: Remove the nmi parameter from the oprofile_perf backend
  x86, perf: Make copy_from_user_nmi() a library function
  perf: Remove perf_event_attr::type check
  x86, perf: P4 PMU - Fix typos in comments and style cleanup
  perf tools: Make test use the preset debugfs path
  perf tools: Add automated tests for events parsing
  perf tools: De-opt the parse_events function
  perf script: Fix display of IP address for non-callchain path
  perf tools: Fix endian conversion reading event attr from file header
  perf tools: Add missing 'node' alias to the hw_cache[] array
  perf probe: Support adding probes on offline kernel modules
  perf probe: Add probed module in front of function
  perf probe: Introduce debuginfo to encapsulate dwarf information
  perf-probe: Move dwarf library routines to dwarf-aux.{c, h}
  perf probe: Remove redundant dwarf functions
  perf probe: Move strtailcmp to string.c
  perf probe: Rename DIE_FIND_CB_FOUND to DIE_FIND_CB_END
  tracing/kprobe: Update symbol reference when loading module
  tracing/kprobes: Support module init function probing
  kprobes: Return -ENOENT if probe point doesn't exist
  ...

5 files changed, 752 insertions, 674 deletions

diff --git a/kernel/events/Makefile b/kernel/events/Makefile
index 1ce23d3d8394..89e5e8aa4c36 100644
--- a/kernel/events/Makefile
+++ b/kernel/events/Makefile
@@ -2,5 +2,5 @@ ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_core.o = -pg
 endif
 
-obj-y := core.o
+obj-y := core.o ring_buffer.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 9efe7108ccaf..b8785e26ee1c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -36,6 +36,8 @@
 #include <linux/ftrace_event.h>
 #include <linux/hw_breakpoint.h>
 
+#include "internal.h"
+
 #include <asm/irq_regs.h>
 
 struct remote_function_call {
@@ -200,6 +202,22 @@ __get_cpu_context(struct perf_event_context *ctx)
 	return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
 }
 
+static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
+			  struct perf_event_context *ctx)
+{
+	raw_spin_lock(&cpuctx->ctx.lock);
+	if (ctx)
+		raw_spin_lock(&ctx->lock);
+}
+
+static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
+			    struct perf_event_context *ctx)
+{
+	if (ctx)
+		raw_spin_unlock(&ctx->lock);
+	raw_spin_unlock(&cpuctx->ctx.lock);
+}
+
 #ifdef CONFIG_CGROUP_PERF
 
 /*
@@ -340,11 +358,8 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
 	rcu_read_lock();
 
 	list_for_each_entry_rcu(pmu, &pmus, entry) {
-
 		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
 
-		perf_pmu_disable(cpuctx->ctx.pmu);
-
 		/*
 		 * perf_cgroup_events says at least one
 		 * context on this CPU has cgroup events.
@@ -353,6 +368,8 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
 		 * events for a context.
 		 */
 		if (cpuctx->ctx.nr_cgroups > 0) {
+			perf_ctx_lock(cpuctx, cpuctx->task_ctx);
+			perf_pmu_disable(cpuctx->ctx.pmu);
 
 			if (mode & PERF_CGROUP_SWOUT) {
 				cpu_ctx_sched_out(cpuctx, EVENT_ALL);
@@ -372,9 +389,9 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
 				cpuctx->cgrp = perf_cgroup_from_task(task);
 				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
 			}
+			perf_pmu_enable(cpuctx->ctx.pmu);
+			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 		}
-
-		perf_pmu_enable(cpuctx->ctx.pmu);
 	}
 
 	rcu_read_unlock();
@@ -731,6 +748,7 @@ static u64 perf_event_time(struct perf_event *event)
 
 /*
  * Update the total_time_enabled and total_time_running fields for a event.
+ * The caller of this function needs to hold the ctx->lock.
  */
 static void update_event_times(struct perf_event *event)
 {
@@ -1105,6 +1123,10 @@ static int __perf_remove_from_context(void *info)
 	raw_spin_lock(&ctx->lock);
 	event_sched_out(event, cpuctx, ctx);
 	list_del_event(event, ctx);
+	if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
+		ctx->is_active = 0;
+		cpuctx->task_ctx = NULL;
+	}
 	raw_spin_unlock(&ctx->lock);
 
 	return 0;
@@ -1454,8 +1476,24 @@ static void add_event_to_ctx(struct perf_event *event,
 	event->tstamp_stopped = tstamp;
 }
 
-static void perf_event_context_sched_in(struct perf_event_context *ctx,
-					struct task_struct *tsk);
+static void task_ctx_sched_out(struct perf_event_context *ctx);
+static void
+ctx_sched_in(struct perf_event_context *ctx,
+	     struct perf_cpu_context *cpuctx,
+	     enum event_type_t event_type,
+	     struct task_struct *task);
+
+static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
+				struct perf_event_context *ctx,
+				struct task_struct *task)
+{
+	cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
+	if (ctx)
+		ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
+	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
+	if (ctx)
+		ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
+}
 
 /*
  * Cross CPU call to install and enable a performance event
@@ -1466,20 +1504,37 @@ static int  __perf_install_in_context(void *info)
 {
 	struct perf_event *event = info;
 	struct perf_event_context *ctx = event->ctx;
-	struct perf_event *leader = event->group_leader;
 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
-	int err;
+	struct perf_event_context *task_ctx = cpuctx->task_ctx;
+	struct task_struct *task = current;
+
+	perf_ctx_lock(cpuctx, task_ctx);
+	perf_pmu_disable(cpuctx->ctx.pmu);
 
 	/*
-	 * In case we're installing a new context to an already running task,
-	 * could also happen before perf_event_task_sched_in() on architectures
-	 * which do context switches with IRQs enabled.
+	 * If there was an active task_ctx schedule it out.
 	 */
-	if (ctx->task && !cpuctx->task_ctx)
-		perf_event_context_sched_in(ctx, ctx->task);
+	if (task_ctx)
+		task_ctx_sched_out(task_ctx);
+
+	/*
+	 * If the context we're installing events in is not the
+	 * active task_ctx, flip them.
+	 */
+	if (ctx->task && task_ctx != ctx) {
+		if (task_ctx)
+			raw_spin_unlock(&task_ctx->lock);
+		raw_spin_lock(&ctx->lock);
+		task_ctx = ctx;
+	}
+
+	if (task_ctx) {
+		cpuctx->task_ctx = task_ctx;
+		task = task_ctx->task;
+	}
+
+	cpu_ctx_sched_out(cpuctx, EVENT_ALL);
 
-	raw_spin_lock(&ctx->lock);
-	ctx->is_active = 1;
 	update_context_time(ctx);
 	/*
 	 * update cgrp time only if current cgrp
@@ -1490,43 +1545,13 @@ static int  __perf_install_in_context(void *info)
 
 	add_event_to_ctx(event, ctx);
 
-	if (!event_filter_match(event))
-		goto unlock;
-
-	/*
-	 * Don't put the event on if it is disabled or if
-	 * it is in a group and the group isn't on.
-	 */
-	if (event->state != PERF_EVENT_STATE_INACTIVE ||
-	    (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
-		goto unlock;
-
 	/*
-	 * An exclusive event can't go on if there are already active
-	 * hardware events, and no hardware event can go on if there
-	 * is already an exclusive event on.
+	 * Schedule everything back in
 	 */
-	if (!group_can_go_on(event, cpuctx, 1))
-		err = -EEXIST;
-	else
-		err = event_sched_in(event, cpuctx, ctx);
-
-	if (err) {
-		/*
-		 * This event couldn't go on.  If it is in a group
-		 * then we have to pull the whole group off.
-		 * If the event group is pinned then put it in error state.
-		 */
-		if (leader != event)
-			group_sched_out(leader, cpuctx, ctx);
-		if (leader->attr.pinned) {
-			update_group_times(leader);
-			leader->state = PERF_EVENT_STATE_ERROR;
-		}
-	}
+	perf_event_sched_in(cpuctx, task_ctx, task);
 
-unlock:
-	raw_spin_unlock(&ctx->lock);
+	perf_pmu_enable(cpuctx->ctx.pmu);
+	perf_ctx_unlock(cpuctx, task_ctx);
 
 	return 0;
 }
@@ -1739,7 +1764,7 @@ out:
 	raw_spin_unlock_irq(&ctx->lock);
 }
 
-static int perf_event_refresh(struct perf_event *event, int refresh)
+int perf_event_refresh(struct perf_event *event, int refresh)
 {
 	/*
 	 * not supported on inherited events
@@ -1752,36 +1777,35 @@ static int perf_event_refresh(struct perf_event *event, int refresh)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(perf_event_refresh);
 
 static void ctx_sched_out(struct perf_event_context *ctx,
 			  struct perf_cpu_context *cpuctx,
 			  enum event_type_t event_type)
 {
 	struct perf_event *event;
+	int is_active = ctx->is_active;
 
-	raw_spin_lock(&ctx->lock);
-	perf_pmu_disable(ctx->pmu);
-	ctx->is_active = 0;
+	ctx->is_active &= ~event_type;
 	if (likely(!ctx->nr_events))
-		goto out;
+		return;
+
 	update_context_time(ctx);
 	update_cgrp_time_from_cpuctx(cpuctx);
-
 	if (!ctx->nr_active)
-		goto out;
+		return;
 
-	if (event_type & EVENT_PINNED) {
+	perf_pmu_disable(ctx->pmu);
+	if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
 		list_for_each_entry(event, &ctx->pinned_groups, group_entry)
 			group_sched_out(event, cpuctx, ctx);
 	}
 
-	if (event_type & EVENT_FLEXIBLE) {
+	if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
 		list_for_each_entry(event, &ctx->flexible_groups, group_entry)
 			group_sched_out(event, cpuctx, ctx);
 	}
-out:
 	perf_pmu_enable(ctx->pmu);
-	raw_spin_unlock(&ctx->lock);
 }
 
 /*
@@ -1929,8 +1953,10 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
 	rcu_read_unlock();
 
 	if (do_switch) {
+		raw_spin_lock(&ctx->lock);
 		ctx_sched_out(ctx, cpuctx, EVENT_ALL);
 		cpuctx->task_ctx = NULL;
+		raw_spin_unlock(&ctx->lock);
 	}
 }
 
@@ -1965,8 +1991,7 @@ void __perf_event_task_sched_out(struct task_struct *task,
 		perf_cgroup_sched_out(task);
 }
 
-static void task_ctx_sched_out(struct perf_event_context *ctx,
-			       enum event_type_t event_type)
+static void task_ctx_sched_out(struct perf_event_context *ctx)
 {
 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
 
@@ -1976,7 +2001,7 @@ static void task_ctx_sched_out(struct perf_event_context *ctx,
 	if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
 		return;
 
-	ctx_sched_out(ctx, cpuctx, event_type);
+	ctx_sched_out(ctx, cpuctx, EVENT_ALL);
 	cpuctx->task_ctx = NULL;
 }
 
@@ -2055,11 +2080,11 @@ ctx_sched_in(struct perf_event_context *ctx,
 	     struct task_struct *task)
 {
 	u64 now;
+	int is_active = ctx->is_active;
 
-	raw_spin_lock(&ctx->lock);
-	ctx->is_active = 1;
+	ctx->is_active |= event_type;
 	if (likely(!ctx->nr_events))
-		goto out;
+		return;
 
 	now = perf_clock();
 	ctx->timestamp = now;
@@ -2068,15 +2093,12 @@ ctx_sched_in(struct perf_event_context *ctx,
 	 * First go through the list and put on any pinned groups
 	 * in order to give them the best chance of going on.
 	 */
-	if (event_type & EVENT_PINNED)
+	if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
 		ctx_pinned_sched_in(ctx, cpuctx);
 
 	/* Then walk through the lower prio flexible groups */
-	if (event_type & EVENT_FLEXIBLE)
+	if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
 		ctx_flexible_sched_in(ctx, cpuctx);
-
-out:
-	raw_spin_unlock(&ctx->lock);
 }
 
 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
@@ -2088,19 +2110,6 @@ static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
 	ctx_sched_in(ctx, cpuctx, event_type, task);
 }
 
-static void task_ctx_sched_in(struct perf_event_context *ctx,
-			      enum event_type_t event_type)
-{
-	struct perf_cpu_context *cpuctx;
-
-	cpuctx = __get_cpu_context(ctx);
-	if (cpuctx->task_ctx == ctx)
-		return;
-
-	ctx_sched_in(ctx, cpuctx, event_type, NULL);
-	cpuctx->task_ctx = ctx;
-}
-
 static void perf_event_context_sched_in(struct perf_event_context *ctx,
 					struct task_struct *task)
 {
@@ -2110,6 +2119,7 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
 	if (cpuctx->task_ctx == ctx)
 		return;
 
+	perf_ctx_lock(cpuctx, ctx);
 	perf_pmu_disable(ctx->pmu);
 	/*
 	 * We want to keep the following priority order:
@@ -2118,18 +2128,18 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
 	 */
 	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
 
-	ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
-	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
-	ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
+	perf_event_sched_in(cpuctx, ctx, task);
 
 	cpuctx->task_ctx = ctx;
 
+	perf_pmu_enable(ctx->pmu);
+	perf_ctx_unlock(cpuctx, ctx);
+
 	/*
 	 * Since these rotations are per-cpu, we need to ensure the
 	 * cpu-context we got scheduled on is actually rotating.
 	 */
 	perf_pmu_rotate_start(ctx->pmu);
-	perf_pmu_enable(ctx->pmu);
 }
 
 /*
@@ -2269,7 +2279,6 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
 	u64 interrupts, now;
 	s64 delta;
 
-	raw_spin_lock(&ctx->lock);
 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
 		if (event->state != PERF_EVENT_STATE_ACTIVE)
 			continue;
@@ -2301,7 +2310,6 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
 		if (delta > 0)
 			perf_adjust_period(event, period, delta);
 	}
-	raw_spin_unlock(&ctx->lock);
 }
 
 /*
@@ -2309,16 +2317,12 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
  */
 static void rotate_ctx(struct perf_event_context *ctx)
 {
-	raw_spin_lock(&ctx->lock);
-
 	/*
 	 * Rotate the first entry last of non-pinned groups. Rotation might be
 	 * disabled by the inheritance code.
 	 */
 	if (!ctx->rotate_disable)
 		list_rotate_left(&ctx->flexible_groups);
-
-	raw_spin_unlock(&ctx->lock);
 }
 
 /*
@@ -2345,6 +2349,7 @@ static void perf_rotate_context(struct perf_cpu_context *cpuctx)
 			rotate = 1;
 	}
 
+	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
 	perf_pmu_disable(cpuctx->ctx.pmu);
 	perf_ctx_adjust_freq(&cpuctx->ctx, interval);
 	if (ctx)
@@ -2355,21 +2360,20 @@ static void perf_rotate_context(struct perf_cpu_context *cpuctx)
 
 	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
 	if (ctx)
-		task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
+		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
 
 	rotate_ctx(&cpuctx->ctx);
 	if (ctx)
 		rotate_ctx(ctx);
 
-	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, current);
-	if (ctx)
-		task_ctx_sched_in(ctx, EVENT_FLEXIBLE);
+	perf_event_sched_in(cpuctx, ctx, current);
 
 done:
 	if (remove)
 		list_del_init(&cpuctx->rotation_list);
 
 	perf_pmu_enable(cpuctx->ctx.pmu);
+	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 }
 
 void perf_event_task_tick(void)
@@ -2424,9 +2428,9 @@ static void perf_event_enable_on_exec(struct perf_event_context *ctx)
 	 * in.
 	 */
 	perf_cgroup_sched_out(current);
-	task_ctx_sched_out(ctx, EVENT_ALL);
 
 	raw_spin_lock(&ctx->lock);
+	task_ctx_sched_out(ctx);
 
 	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
 		ret = event_enable_on_exec(event, ctx);
@@ -2835,16 +2839,12 @@ retry:
 		unclone_ctx(ctx);
 		++ctx->pin_count;
 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
-	}
-
-	if (!ctx) {
+	} else {
 		ctx = alloc_perf_context(pmu, task);
 		err = -ENOMEM;
 		if (!ctx)
 			goto errout;
 
-		get_ctx(ctx);
-
 		err = 0;
 		mutex_lock(&task->perf_event_mutex);
 		/*
@@ -2856,14 +2856,14 @@ retry:
 		else if (task->perf_event_ctxp[ctxn])
 			err = -EAGAIN;
 		else {
+			get_ctx(ctx);
 			++ctx->pin_count;
 			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
 		}
 		mutex_unlock(&task->perf_event_mutex);
 
 		if (unlikely(err)) {
-			put_task_struct(task);
-			kfree(ctx);
+			put_ctx(ctx);
 
 			if (err == -EAGAIN)
 				goto retry;
@@ -2890,7 +2890,7 @@ static void free_event_rcu(struct rcu_head *head)
 	kfree(event);
 }
 
-static void perf_buffer_put(struct perf_buffer *buffer);
+static void ring_buffer_put(struct ring_buffer *rb);
 
 static void free_event(struct perf_event *event)
 {
@@ -2913,9 +2913,9 @@ static void free_event(struct perf_event *event)
 		}
 	}
 
-	if (event->buffer) {
-		perf_buffer_put(event->buffer);
-		event->buffer = NULL;
+	if (event->rb) {
+		ring_buffer_put(event->rb);
+		event->rb = NULL;
 	}
 
 	if (is_cgroup_event(event))
@@ -2934,12 +2934,6 @@ int perf_event_release_kernel(struct perf_event *event)
 {
 	struct perf_event_context *ctx = event->ctx;
 
-	/*
-	 * Remove from the PMU, can't get re-enabled since we got
-	 * here because the last ref went.
-	 */
-	perf_event_disable(event);
-
 	WARN_ON_ONCE(ctx->parent_ctx);
 	/*
 	 * There are two ways this annotation is useful:
@@ -2956,8 +2950,8 @@ int perf_event_release_kernel(struct perf_event *event)
 	mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
 	raw_spin_lock_irq(&ctx->lock);
 	perf_group_detach(event);
-	list_del_event(event, ctx);
 	raw_spin_unlock_irq(&ctx->lock);
+	perf_remove_from_context(event);
 	mutex_unlock(&ctx->mutex);
 
 	free_event(event);
@@ -3149,13 +3143,13 @@ perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 static unsigned int perf_poll(struct file *file, poll_table *wait)
 {
 	struct perf_event *event = file->private_data;
-	struct perf_buffer *buffer;
+	struct ring_buffer *rb;
 	unsigned int events = POLL_HUP;
 
 	rcu_read_lock();
-	buffer = rcu_dereference(event->buffer);
-	if (buffer)
-		events = atomic_xchg(&buffer->poll, 0);
+	rb = rcu_dereference(event->rb);
+	if (rb)
+		events = atomic_xchg(&rb->poll, 0);
 	rcu_read_unlock();
 
 	poll_wait(file, &event->waitq, wait);
@@ -3358,6 +3352,18 @@ static int perf_event_index(struct perf_event *event)
 	return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
 }
 
+static void calc_timer_values(struct perf_event *event,
+				u64 *running,
+				u64 *enabled)
+{
+	u64 now, ctx_time;
+
+	now = perf_clock();
+	ctx_time = event->shadow_ctx_time + now;
+	*enabled = ctx_time - event->tstamp_enabled;
+	*running = ctx_time - event->tstamp_running;
+}
+
 /*
  * 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
@@ -3366,14 +3372,25 @@ static int perf_event_index(struct perf_event *event)
 void perf_event_update_userpage(struct perf_event *event)
 {
 	struct perf_event_mmap_page *userpg;
-	struct perf_buffer *buffer;
+	struct ring_buffer *rb;
+	u64 enabled, running;
 
 	rcu_read_lock();
-	buffer = rcu_dereference(event->buffer);
-	if (!buffer)
+	/*
+	 * compute total_time_enabled, total_time_running
+	 * based on snapshot values taken when the event
+	 * was last scheduled in.
+	 *
+	 * we cannot simply called update_context_time()
+	 * because of locking issue as we can be called in
+	 * NMI context
+	 */
+	calc_timer_values(event, &enabled, &running);
+	rb = rcu_dereference(event->rb);
+	if (!rb)
 		goto unlock;
 
-	userpg = buffer->user_page;
+	userpg = rb->user_page;
 
 	/*
 	 * Disable preemption so as to not let the corresponding user-space
@@ -3387,10 +3404,10 @@ void perf_event_update_userpage(struct perf_event *event)
 	if (event->state == PERF_EVENT_STATE_ACTIVE)
 		userpg->offset -= local64_read(&event->hw.prev_count);
 
-	userpg->time_enabled = event->total_time_enabled +
+	userpg->time_enabled = enabled +
 			atomic64_read(&event->child_total_time_enabled);
 
-	userpg->time_running = event->total_time_running +
+	userpg->time_running = running +
 			atomic64_read(&event->child_total_time_running);
 
 	barrier();
@@ -3400,220 +3417,10 @@ unlock:
 	rcu_read_unlock();
 }
 
-static unsigned long perf_data_size(struct perf_buffer *buffer);
-
-static void
-perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
-{
-	long max_size = perf_data_size(buffer);
-
-	if (watermark)
-		buffer->watermark = min(max_size, watermark);
-
-	if (!buffer->watermark)
-		buffer->watermark = max_size / 2;
-
-	if (flags & PERF_BUFFER_WRITABLE)
-		buffer->writable = 1;
-
-	atomic_set(&buffer->refcount, 1);
-}
-
-#ifndef CONFIG_PERF_USE_VMALLOC
-
-/*
- * Back perf_mmap() with regular GFP_KERNEL-0 pages.
- */
-
-static struct page *
-perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
-{
-	if (pgoff > buffer->nr_pages)
-		return NULL;
-
-	if (pgoff == 0)
-		return virt_to_page(buffer->user_page);
-
-	return virt_to_page(buffer->data_pages[pgoff - 1]);
-}
-
-static void *perf_mmap_alloc_page(int cpu)
-{
-	struct page *page;
-	int node;
-
-	node = (cpu == -1) ? cpu : cpu_to_node(cpu);
-	page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
-	if (!page)
-		return NULL;
-
-	return page_address(page);
-}
-
-static struct perf_buffer *
-perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
-{
-	struct perf_buffer *buffer;
-	unsigned long size;
-	int i;
-
-	size = sizeof(struct perf_buffer);
-	size += nr_pages * sizeof(void *);
-
-	buffer = kzalloc(size, GFP_KERNEL);
-	if (!buffer)
-		goto fail;
-
-	buffer->user_page = perf_mmap_alloc_page(cpu);
-	if (!buffer->user_page)
-		goto fail_user_page;
-
-	for (i = 0; i < nr_pages; i++) {
-		buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
-		if (!buffer->data_pages[i])
-			goto fail_data_pages;
-	}
-
-	buffer->nr_pages = nr_pages;
-
-	perf_buffer_init(buffer, watermark, flags);
-
-	return buffer;
-
-fail_data_pages:
-	for (i--; i >= 0; i--)
-		free_page((unsigned long)buffer->data_pages[i]);
-
-	free_page((unsigned long)buffer->user_page);
-
-fail_user_page:
-	kfree(buffer);
-
-fail:
-	return NULL;
-}
-
-static void perf_mmap_free_page(unsigned long addr)
-{
-	struct page *page = virt_to_page((void *)addr);
-
-	page->mapping = NULL;
-	__free_page(page);
-}
-
-static void perf_buffer_free(struct perf_buffer *buffer)
-{
-	int i;
-
-	perf_mmap_free_page((unsigned long)buffer->user_page);
-	for (i = 0; i < buffer->nr_pages; i++)
-		perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
-	kfree(buffer);
-}
-
-static inline int page_order(struct perf_buffer *buffer)
-{
-	return 0;
-}
-
-#else
-
-/*
- * Back perf_mmap() with vmalloc memory.
- *
- * Required for architectures that have d-cache aliasing issues.
- */
-
-static inline int page_order(struct perf_buffer *buffer)
-{
-	return buffer->page_order;
-}
-
-static struct page *
-perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
-{
-	if (pgoff > (1UL << page_order(buffer)))
-		return NULL;
-
-	return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
-}
-
-static void perf_mmap_unmark_page(void *addr)
-{
-	struct page *page = vmalloc_to_page(addr);
-
-	page->mapping = NULL;
-}
-
-static void perf_buffer_free_work(struct work_struct *work)
-{
-	struct perf_buffer *buffer;
-	void *base;
-	int i, nr;
-
-	buffer = container_of(work, struct perf_buffer, work);
-	nr = 1 << page_order(buffer);
-
-	base = buffer->user_page;
-	for (i = 0; i < nr + 1; i++)
-		perf_mmap_unmark_page(base + (i * PAGE_SIZE));
-
-	vfree(base);
-	kfree(buffer);
-}
-
-static void perf_buffer_free(struct perf_buffer *buffer)
-{
-	schedule_work(&buffer->work);
-}
-
-static struct perf_buffer *
-perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
-{
-	struct perf_buffer *buffer;
-	unsigned long size;
-	void *all_buf;
-
-	size = sizeof(struct perf_buffer);
-	size += sizeof(void *);
-
-	buffer = kzalloc(size, GFP_KERNEL);
-	if (!buffer)
-		goto fail;
-
-	INIT_WORK(&buffer->work, perf_buffer_free_work);
-
-	all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
-	if (!all_buf)
-		goto fail_all_buf;
-
-	buffer->user_page = all_buf;
-	buffer->data_pages[0] = all_buf + PAGE_SIZE;
-	buffer->page_order = ilog2(nr_pages);
-	buffer->nr_pages = 1;
-
-	perf_buffer_init(buffer, watermark, flags);
-
-	return buffer;
-
-fail_all_buf:
-	kfree(buffer);
-
-fail:
-	return NULL;
-}
-
-#endif
-
-static unsigned long perf_data_size(struct perf_buffer *buffer)
-{
-	return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
-}
-
 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct perf_event *event = vma->vm_file->private_data;
-	struct perf_buffer *buffer;
+	struct ring_buffer *rb;
 	int ret = VM_FAULT_SIGBUS;
 
 	if (vmf->flags & FAULT_FLAG_MKWRITE) {
@@ -3623,14 +3430,14 @@ static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	}
 
 	rcu_read_lock();
-	buffer = rcu_dereference(event->buffer);
-	if (!buffer)
+	rb = rcu_dereference(event->rb);
+	if (!rb)
 		goto unlock;
 
 	if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
 		goto unlock;
 
-	vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
+	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
 	if (!vmf->page)
 		goto unlock;
 
@@ -3645,35 +3452,35 @@ unlock:
 	return ret;
 }
 
-static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
+static void rb_free_rcu(struct rcu_head *rcu_head)
 {
-	struct perf_buffer *buffer;
+	struct ring_buffer *rb;
 
-	buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
-	perf_buffer_free(buffer);
+	rb = container_of(rcu_head, struct ring_buffer, rcu_head);
+	rb_free(rb);
 }
 
-static struct perf_buffer *perf_buffer_get(struct perf_event *event)
+static struct ring_buffer *ring_buffer_get(struct perf_event *event)
 {
-	struct perf_buffer *buffer;
+	struct ring_buffer *rb;
 
 	rcu_read_lock();
-	buffer = rcu_dereference(event->buffer);
-	if (buffer) {
-		if (!atomic_inc_not_zero(&buffer->refcount))
-			buffer = NULL;
+	rb = rcu_dereference(event->rb);
+	if (rb) {
+		if (!atomic_inc_not_zero(&rb->refcount))
+			rb = NULL;
 	}
 	rcu_read_unlock();
 
-	return buffer;
+	return rb;
 }
 
-static void perf_buffer_put(struct perf_buffer *buffer)
+static void ring_buffer_put(struct ring_buffer *rb)
 {
-	if (!atomic_dec_and_test(&buffer->refcount))
+	if (!atomic_dec_and_test(&rb->refcount))
 		return;
 
-	call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
+	call_rcu(&rb->rcu_head, rb_free_rcu);
 }
 
 static void perf_mmap_open(struct vm_area_struct *vma)
@@ -3688,16 +3495,16 @@ static void perf_mmap_close(struct vm_area_struct *vma)
 	struct perf_event *event = vma->vm_file->private_data;
 
 	if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
-		unsigned long size = perf_data_size(event->buffer);
+		unsigned long size = perf_data_size(event->rb);
 		struct user_struct *user = event->mmap_user;
-		struct perf_buffer *buffer = event->buffer;
+		struct ring_buffer *rb = event->rb;
 
 		atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
 		vma->vm_mm->locked_vm -= event->mmap_locked;
-		rcu_assign_pointer(event->buffer, NULL);
+		rcu_assign_pointer(event->rb, NULL);
 		mutex_unlock(&event->mmap_mutex);
 
-		perf_buffer_put(buffer);
+		ring_buffer_put(rb);
 		free_uid(user);
 	}
 }
@@ -3715,7 +3522,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 	unsigned long user_locked, user_lock_limit;
 	struct user_struct *user = current_user();
 	unsigned long locked, lock_limit;
-	struct perf_buffer *buffer;
+	struct ring_buffer *rb;
 	unsigned long vma_size;
 	unsigned long nr_pages;
 	long user_extra, extra;
@@ -3724,7 +3531,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 	/*
 	 * Don't allow mmap() of inherited per-task counters. This would
 	 * create a performance issue due to all children writing to the
-	 * same buffer.
+	 * same rb.
 	 */
 	if (event->cpu == -1 && event->attr.inherit)
 		return -EINVAL;
@@ -3736,7 +3543,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 	nr_pages = (vma_size / PAGE_SIZE) - 1;
 
 	/*
-	 * If we have buffer pages ensure they're a power-of-two number, so we
+	 * If we have rb 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))
@@ -3750,9 +3557,9 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 
 	WARN_ON_ONCE(event->ctx->parent_ctx);
 	mutex_lock(&event->mmap_mutex);
-	if (event->buffer) {
-		if (event->buffer->nr_pages == nr_pages)
-			atomic_inc(&event->buffer->refcount);
+	if (event->rb) {
+		if (event->rb->nr_pages == nr_pages)
+			atomic_inc(&event->rb->refcount);
 		else
 			ret = -EINVAL;
 		goto unlock;
@@ -3782,18 +3589,20 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 		goto unlock;
 	}
 
-	WARN_ON(event->buffer);
+	WARN_ON(event->rb);
 
 	if (vma->vm_flags & VM_WRITE)
-		flags |= PERF_BUFFER_WRITABLE;
+		flags |= RING_BUFFER_WRITABLE;
 
-	buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
-				   event->cpu, flags);
-	if (!buffer) {
+	rb = rb_alloc(nr_pages, 
+		event->attr.watermark ? event->attr.wakeup_watermark : 0,
+		event->cpu, flags);
+
+	if (!rb) {
 		ret = -ENOMEM;
 		goto unlock;
 	}
-	rcu_assign_pointer(event->buffer, buffer);
+	rcu_assign_pointer(event->rb, rb);
 
 	atomic_long_add(user_extra, &user->locked_vm);
 	event->mmap_locked = extra;
@@ -3892,117 +3701,6 @@ int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
 }
 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
 
-/*
- * Output
- */
-static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
-			      unsigned long offset, unsigned long head)
-{
-	unsigned long mask;
-
-	if (!buffer->writable)
-		return true;
-
-	mask = perf_data_size(buffer) - 1;
-
-	offset = (offset - tail) & mask;
-	head   = (head   - tail) & mask;
-
-	if ((int)(head - offset) < 0)
-		return false;
-
-	return true;
-}
-
-static void perf_output_wakeup(struct perf_output_handle *handle)
-{
-	atomic_set(&handle->buffer->poll, POLL_IN);
-
-	if (handle->nmi) {
-		handle->event->pending_wakeup = 1;
-		irq_work_queue(&handle->event->pending);
-	} else
-		perf_event_wakeup(handle->event);
-}
-
-/*
- * We need to ensure a later event_id 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.
- *
- * We only publish the head (and generate a wakeup) when the outer-most
- * event completes.
- */
-static void perf_output_get_handle(struct perf_output_handle *handle)
-{
-	struct perf_buffer *buffer = handle->buffer;
-
-	preempt_disable();
-	local_inc(&buffer->nest);
-	handle->wakeup = local_read(&buffer->wakeup);
-}
-
-static void perf_output_put_handle(struct perf_output_handle *handle)
-{
-	struct perf_buffer *buffer = handle->buffer;
-	unsigned long head;
-
-again:
-	head = local_read(&buffer->head);
-
-	/*
-	 * IRQ/NMI can happen here, which means we can miss a head update.
-	 */
-
-	if (!local_dec_and_test(&buffer->nest))
-		goto out;
-
-	/*
-	 * Publish the known good head. Rely on the full barrier implied
-	 * by atomic_dec_and_test() order the buffer->head read and this
-	 * write.
-	 */
-	buffer->user_page->data_head = head;
-
-	/*
-	 * Now check if we missed an update, rely on the (compiler)
-	 * barrier in atomic_dec_and_test() to re-read buffer->head.
-	 */
-	if (unlikely(head != local_read(&buffer->head))) {
-		local_inc(&buffer->nest);
-		goto again;
-	}
-
-	if (handle->wakeup != local_read(&buffer->wakeup))
-		perf_output_wakeup(handle);
-
-out:
-	preempt_enable();
-}
-
-__always_inline void perf_output_copy(struct perf_output_handle *handle,
-		      const void *buf, unsigned int len)
-{
-	do {
-		unsigned long size = min_t(unsigned long, handle->size, len);
-
-		memcpy(handle->addr, buf, size);
-
-		len -= size;
-		handle->addr += size;
-		buf += size;
-		handle->size -= size;
-		if (!handle->size) {
-			struct perf_buffer *buffer = handle->buffer;
-
-			handle->page++;
-			handle->page &= buffer->nr_pages - 1;
-			handle->addr = buffer->data_pages[handle->page];
-			handle->size = PAGE_SIZE << page_order(buffer);
-		}
-	} while (len);
-}
-
 static void __perf_event_header__init_id(struct perf_event_header *header,
 					 struct perf_sample_data *data,
 					 struct perf_event *event)
@@ -4033,9 +3731,9 @@ static void __perf_event_header__init_id(struct perf_event_header *header,
 	}
 }
 
-static void perf_event_header__init_id(struct perf_event_header *header,
-				       struct perf_sample_data *data,
-				       struct perf_event *event)
+void perf_event_header__init_id(struct perf_event_header *header,
+				struct perf_sample_data *data,
+				struct perf_event *event)
 {
 	if (event->attr.sample_id_all)
 		__perf_event_header__init_id(header, data, event);
@@ -4062,121 +3760,14 @@ static void __perf_event__output_id_sample(struct perf_output_handle *handle,
 		perf_output_put(handle, data->cpu_entry);
 }
 
-static void perf_event__output_id_sample(struct perf_event *event,
-					 struct perf_output_handle *handle,
-					 struct perf_sample_data *sample)
+void perf_event__output_id_sample(struct perf_event *event,
+				  struct perf_output_handle *handle,
+				  struct perf_sample_data *sample)
 {
 	if (event->attr.sample_id_all)
 		__perf_event__output_id_sample(handle, sample);
 }
 
-int perf_output_begin(struct perf_output_handle *handle,
-		      struct perf_event *event, unsigned int size,
-		      int nmi, int sample)
-{
-	struct perf_buffer *buffer;
-	unsigned long tail, offset, head;
-	int have_lost;
-	struct perf_sample_data sample_data;
-	struct {
-		struct perf_event_header header;
-		u64			 id;
-		u64			 lost;
-	} lost_event;
-
-	rcu_read_lock();
-	/*
-	 * For inherited events we send all the output towards the parent.
-	 */
-	if (event->parent)
-		event = event->parent;
-
-	buffer = rcu_dereference(event->buffer);
-	if (!buffer)
-		goto out;
-
-	handle->buffer	= buffer;
-	handle->event	= event;
-	handle->nmi	= nmi;
-	handle->sample	= sample;
-
-	if (!buffer->nr_pages)
-		goto out;
-
-	have_lost = local_read(&buffer->lost);
-	if (have_lost) {
-		lost_event.header.size = sizeof(lost_event);
-		perf_event_header__init_id(&lost_event.header, &sample_data,
-					   event);
-		size += lost_event.header.size;
-	}
-
-	perf_output_get_handle(handle);
-
-	do {
-		/*
-		 * Userspace could choose to issue a mb() before updating the
-		 * tail pointer. So that all reads will be completed before the
-		 * write is issued.
-		 */
-		tail = ACCESS_ONCE(buffer->user_page->data_tail);
-		smp_rmb();
-		offset = head = local_read(&buffer->head);
-		head += size;
-		if (unlikely(!perf_output_space(buffer, tail, offset, head)))
-			goto fail;
-	} while (local_cmpxchg(&buffer->head, offset, head) != offset);
-
-	if (head - local_read(&buffer->wakeup) > buffer->watermark)
-		local_add(buffer->watermark, &buffer->wakeup);
-
-	handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
-	handle->page &= buffer->nr_pages - 1;
-	handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
-	handle->addr = buffer->data_pages[handle->page];
-	handle->addr += handle->size;
-	handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
-
-	if (have_lost) {
-		lost_event.header.type = PERF_RECORD_LOST;
-		lost_event.header.misc = 0;
-		lost_event.id          = event->id;
-		lost_event.lost        = local_xchg(&buffer->lost, 0);
-
-		perf_output_put(handle, lost_event);
-		perf_event__output_id_sample(event, handle, &sample_data);
-	}
-
-	return 0;
-
-fail:
-	local_inc(&buffer->lost);
-	perf_output_put_handle(handle);
-out:
-	rcu_read_unlock();
-
-	return -ENOSPC;
-}
-
-void perf_output_end(struct perf_output_handle *handle)
-{
-	struct perf_event *event = handle->event;
-	struct perf_buffer *buffer = handle->buffer;
-
-	int wakeup_events = event->attr.wakeup_events;
-
-	if (handle->sample && wakeup_events) {
-		int events = local_inc_return(&buffer->events);
-		if (events >= wakeup_events) {
-			local_sub(wakeup_events, &buffer->events);
-			local_inc(&buffer->wakeup);
-		}
-	}
-
-	perf_output_put_handle(handle);
-	rcu_read_unlock();
-}
-
 static void perf_output_read_one(struct perf_output_handle *handle,
 				 struct perf_event *event,
 				 u64 enabled, u64 running)
@@ -4197,7 +3788,7 @@ static void perf_output_read_one(struct perf_output_handle *handle,
 	if (read_format & PERF_FORMAT_ID)
 		values[n++] = primary_event_id(event);
 
-	perf_output_copy(handle, values, n * sizeof(u64));
+	__output_copy(handle, values, n * sizeof(u64));
 }
 
 /*
@@ -4227,7 +3818,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 	if (read_format & PERF_FORMAT_ID)
 		values[n++] = primary_event_id(leader);
 
-	perf_output_copy(handle, values, n * sizeof(u64));
+	__output_copy(handle, values, n * sizeof(u64));
 
 	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
 		n = 0;
@@ -4239,7 +3830,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 		if (read_format & PERF_FORMAT_ID)
 			values[n++] = primary_event_id(sub);
 
-		perf_output_copy(handle, values, n * sizeof(u64));
+		__output_copy(handle, values, n * sizeof(u64));
 	}
 }
 
@@ -4249,7 +3840,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 static void perf_output_read(struct perf_output_handle *handle,
 			     struct perf_event *event)
 {
-	u64 enabled = 0, running = 0, now, ctx_time;
+	u64 enabled = 0, running = 0;
 	u64 read_format = event->attr.read_format;
 
 	/*
@@ -4261,12 +3852,8 @@ static void perf_output_read(struct perf_output_handle *handle,
 	 * because of locking issue as we are called in
 	 * NMI context
 	 */
-	if (read_format & PERF_FORMAT_TOTAL_TIMES) {
-		now = perf_clock();
-		ctx_time = event->shadow_ctx_time + now;
-		enabled = ctx_time - event->tstamp_enabled;
-		running = ctx_time - event->tstamp_running;
-	}
+	if (read_format & PERF_FORMAT_TOTAL_TIMES)
+		calc_timer_values(event, &enabled, &running);
 
 	if (event->attr.read_format & PERF_FORMAT_GROUP)
 		perf_output_read_group(handle, event, enabled, running);
@@ -4319,7 +3906,7 @@ void perf_output_sample(struct perf_output_handle *handle,
 
 			size *= sizeof(u64);
 
-			perf_output_copy(handle, data->callchain, size);
+			__output_copy(handle, data->callchain, size);
 		} else {
 			u64 nr = 0;
 			perf_output_put(handle, nr);
@@ -4329,8 +3916,8 @@ void perf_output_sample(struct perf_output_handle *handle,
 	if (sample_type & PERF_SAMPLE_RAW) {
 		if (data->raw) {
 			perf_output_put(handle, data->raw->size);
-			perf_output_copy(handle, data->raw->data,
-					 data->raw->size);
+			__output_copy(handle, data->raw->data,
+					   data->raw->size);
 		} else {
 			struct {
 				u32	size;
@@ -4342,6 +3929,20 @@ void perf_output_sample(struct perf_output_handle *handle,
 			perf_output_put(handle, raw);
 		}
 	}
+
+	if (!event->attr.watermark) {
+		int wakeup_events = event->attr.wakeup_events;
+
+		if (wakeup_events) {
+			struct ring_buffer *rb = handle->rb;
+			int events = local_inc_return(&rb->events);
+
+			if (events >= wakeup_events) {
+				local_sub(wakeup_events, &rb->events);
+				local_inc(&rb->wakeup);
+			}
+		}
+	}
 }
 
 void perf_prepare_sample(struct perf_event_header *header,
@@ -4386,7 +3987,7 @@ void perf_prepare_sample(struct perf_event_header *header,
 	}
 }
 
-static void perf_event_output(struct perf_event *event, int nmi,
+static void perf_event_output(struct perf_event *event,
 				struct perf_sample_data *data,
 				struct pt_regs *regs)
 {
@@ -4398,7 +3999,7 @@ static void perf_event_output(struct perf_event *event, int nmi,
 
 	perf_prepare_sample(&header, data, event, regs);
 
-	if (perf_output_begin(&handle, event, header.size, nmi, 1))
+	if (perf_output_begin(&handle, event, header.size))
 		goto exit;
 
 	perf_output_sample(&handle, &header, data, event);
@@ -4438,7 +4039,7 @@ perf_event_read_event(struct perf_event *event,
 	int ret;
 
 	perf_event_header__init_id(&read_event.header, &sample, event);
-	ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
+	ret = perf_output_begin(&handle, event, read_event.header.size);
 	if (ret)
 		return;
 
@@ -4481,7 +4082,7 @@ static void perf_event_task_output(struct perf_event *event,
 	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
 
 	ret = perf_output_begin(&handle, event,
-				task_event->event_id.header.size, 0, 0);
+				task_event->event_id.header.size);
 	if (ret)
 		goto out;
 
@@ -4618,7 +4219,7 @@ static void perf_event_comm_output(struct perf_event *event,
 
 	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
 	ret = perf_output_begin(&handle, event,
-				comm_event->event_id.header.size, 0, 0);
+				comm_event->event_id.header.size);
 
 	if (ret)
 		goto out;
@@ -4627,7 +4228,7 @@ static void perf_event_comm_output(struct perf_event *event,
 	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
 
 	perf_output_put(&handle, comm_event->event_id);
-	perf_output_copy(&handle, comm_event->comm,
+	__output_copy(&handle, comm_event->comm,
 				   comm_event->comm_size);
 
 	perf_event__output_id_sample(event, &handle, &sample);
@@ -4765,7 +4366,7 @@ static void perf_event_mmap_output(struct perf_event *event,
 
 	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
 	ret = perf_output_begin(&handle, event,
-				mmap_event->event_id.header.size, 0, 0);
+				mmap_event->event_id.header.size);
 	if (ret)
 		goto out;
 
@@ -4773,7 +4374,7 @@ static void perf_event_mmap_output(struct perf_event *event,
 	mmap_event->event_id.tid = perf_event_tid(event, current);
 
 	perf_output_put(&handle, mmap_event->event_id);
-	perf_output_copy(&handle, mmap_event->file_name,
+	__output_copy(&handle, mmap_event->file_name,
 				   mmap_event->file_size);
 
 	perf_event__output_id_sample(event, &handle, &sample);
@@ -4829,7 +4430,7 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
 
 	if (file) {
 		/*
-		 * d_path works from the end of the buffer backwards, so we
+		 * d_path works from the end of the rb backwards, so we
 		 * need to add enough zero bytes after the string to handle
 		 * the 64bit alignment we do later.
 		 */
@@ -4960,7 +4561,7 @@ static void perf_log_throttle(struct perf_event *event, int enable)
 	perf_event_header__init_id(&throttle_event.header, &sample, event);
 
 	ret = perf_output_begin(&handle, event,
-				throttle_event.header.size, 1, 0);
+				throttle_event.header.size);
 	if (ret)
 		return;
 
@@ -4973,7 +4574,7 @@ static void perf_log_throttle(struct perf_event *event, int enable)
  * Generic event overflow handling, sampling.
  */
 
-static int __perf_event_overflow(struct perf_event *event, int nmi,
+static int __perf_event_overflow(struct perf_event *event,
 				   int throttle, struct perf_sample_data *data,
 				   struct pt_regs *regs)
 {
@@ -5016,34 +4617,28 @@ static int __perf_event_overflow(struct perf_event *event, int nmi,
 	if (events && atomic_dec_and_test(&event->event_limit)) {
 		ret = 1;
 		event->pending_kill = POLL_HUP;
-		if (nmi) {
-			event->pending_disable = 1;
-			irq_work_queue(&event->pending);
-		} else
-			perf_event_disable(event);
+		event->pending_disable = 1;
+		irq_work_queue(&event->pending);
 	}
 
 	if (event->overflow_handler)
-		event->overflow_handler(event, nmi, data, regs);
+		event->overflow_handler(event, data, regs);
 	else
-		perf_event_output(event, nmi, data, regs);
+		perf_event_output(event, data, regs);
 
 	if (event->fasync && event->pending_kill) {
-		if (nmi) {
-			event->pending_wakeup = 1;
-			irq_work_queue(&event->pending);
-		} else
-			perf_event_wakeup(event);
+		event->pending_wakeup = 1;
+		irq_work_queue(&event->pending);
 	}
 
 	return ret;
 }
 
-int perf_event_overflow(struct perf_event *event, int nmi,
+int perf_event_overflow(struct perf_event *event,
 			  struct perf_sample_data *data,
 			  struct pt_regs *regs)
 {
-	return __perf_event_overflow(event, nmi, 1, data, regs);
+	return __perf_event_overflow(event, 1, data, regs);
 }
 
 /*
@@ -5092,7 +4687,7 @@ again:
 }
 
 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
-				    int nmi, struct perf_sample_data *data,
+				    struct perf_sample_data *data,
 				    struct pt_regs *regs)
 {
 	struct hw_perf_event *hwc = &event->hw;
@@ -5106,7 +4701,7 @@ static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
 		return;
 
 	for (; overflow; overflow--) {
-		if (__perf_event_overflow(event, nmi, throttle,
+		if (__perf_event_overflow(event, throttle,
 					    data, regs)) {
 			/*
 			 * We inhibit the overflow from happening when
@@ -5119,7 +4714,7 @@ static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
 }
 
 static void perf_swevent_event(struct perf_event *event, u64 nr,
-			       int nmi, struct perf_sample_data *data,
+			       struct perf_sample_data *data,
 			       struct pt_regs *regs)
 {
 	struct hw_perf_event *hwc = &event->hw;
@@ -5133,12 +4728,12 @@ static void perf_swevent_event(struct perf_event *event, u64 nr,
 		return;
 
 	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
-		return perf_swevent_overflow(event, 1, nmi, data, regs);
+		return perf_swevent_overflow(event, 1, data, regs);
 
 	if (local64_add_negative(nr, &hwc->period_left))
 		return;
 
-	perf_swevent_overflow(event, 0, nmi, data, regs);
+	perf_swevent_overflow(event, 0, data, regs);
 }
 
 static int perf_exclude_event(struct perf_event *event,
@@ -5226,7 +4821,7 @@ find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
 }
 
 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
-				    u64 nr, int nmi,
+				    u64 nr,
 				    struct perf_sample_data *data,
 				    struct pt_regs *regs)
 {
@@ -5242,7 +4837,7 @@ static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
 
 	hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
 		if (perf_swevent_match(event, type, event_id, data, regs))
-			perf_swevent_event(event, nr, nmi, data, regs);
+			perf_swevent_event(event, nr, data, regs);
 	}
 end:
 	rcu_read_unlock();
@@ -5263,8 +4858,7 @@ inline void perf_swevent_put_recursion_context(int rctx)
 	put_recursion_context(swhash->recursion, rctx);
 }
 
-void __perf_sw_event(u32 event_id, u64 nr, int nmi,
-			    struct pt_regs *regs, u64 addr)
+void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
 {
 	struct perf_sample_data data;
 	int rctx;
@@ -5276,7 +4870,7 @@ void __perf_sw_event(u32 event_id, u64 nr, int nmi,
 
 	perf_sample_data_init(&data, addr);
 
-	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
+	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
 
 	perf_swevent_put_recursion_context(rctx);
 	preempt_enable_notrace();
@@ -5524,7 +5118,7 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
 
 	hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
 		if (perf_tp_event_match(event, &data, regs))
-			perf_swevent_event(event, count, 1, &data, regs);
+			perf_swevent_event(event, count, &data, regs);
 	}
 
 	perf_swevent_put_recursion_context(rctx);
@@ -5617,7 +5211,7 @@ void perf_bp_event(struct perf_event *bp, void *data)
 	perf_sample_data_init(&sample, bp->attr.bp_addr);
 
 	if (!bp->hw.state && !perf_exclude_event(bp, regs))
-		perf_swevent_event(bp, 1, 1, &sample, regs);
+		perf_swevent_event(bp, 1, &sample, regs);
 }
 #endif
 
@@ -5646,7 +5240,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
 
 	if (regs && !perf_exclude_event(event, regs)) {
 		if (!(event->attr.exclude_idle && current->pid == 0))
-			if (perf_event_overflow(event, 0, &data, regs))
+			if (perf_event_overflow(event, &data, regs))
 				ret = HRTIMER_NORESTART;
 	}
 
@@ -5986,6 +5580,7 @@ free_dev:
 }
 
 static struct lock_class_key cpuctx_mutex;
+static struct lock_class_key cpuctx_lock;
 
 int perf_pmu_register(struct pmu *pmu, char *name, int type)
 {
@@ -6036,6 +5631,7 @@ skip_type:
 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
 		__perf_event_init_context(&cpuctx->ctx);
 		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
+		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
 		cpuctx->ctx.type = cpu_context;
 		cpuctx->ctx.pmu = pmu;
 		cpuctx->jiffies_interval = 1;
@@ -6150,7 +5746,8 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 		 struct task_struct *task,
 		 struct perf_event *group_leader,
 		 struct perf_event *parent_event,
-		 perf_overflow_handler_t overflow_handler)
+		 perf_overflow_handler_t overflow_handler,
+		 void *context)
 {
 	struct pmu *pmu;
 	struct perf_event *event;
@@ -6208,10 +5805,13 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 #endif
 	}
 
-	if (!overflow_handler && parent_event)
+	if (!overflow_handler && parent_event) {
 		overflow_handler = parent_event->overflow_handler;
+		context = parent_event->overflow_handler_context;
+	}
 
 	event->overflow_handler	= overflow_handler;
+	event->overflow_handler_context = context;
 
 	if (attr->disabled)
 		event->state = PERF_EVENT_STATE_OFF;
@@ -6326,13 +5926,6 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
 	if (ret)
 		return -EFAULT;
 
-	/*
-	 * If the type exists, the corresponding creation will verify
-	 * the attr->config.
-	 */
-	if (attr->type >= PERF_TYPE_MAX)
-		return -EINVAL;
-
 	if (attr->__reserved_1)
 		return -EINVAL;
 
@@ -6354,7 +5947,7 @@ err_size:
 static int
 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
 {
-	struct perf_buffer *buffer = NULL, *old_buffer = NULL;
+	struct ring_buffer *rb = NULL, *old_rb = NULL;
 	int ret = -EINVAL;
 
 	if (!output_event)
@@ -6371,7 +5964,7 @@ perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
 		goto out;
 
 	/*
-	 * If its not a per-cpu buffer, it must be the same task.
+	 * If its not a per-cpu rb, it must be the same task.
 	 */
 	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
 		goto out;
@@ -6383,20 +5976,20 @@ set:
 		goto unlock;
 
 	if (output_event) {
-		/* get the buffer we want to redirect to */
-		buffer = perf_buffer_get(output_event);
-		if (!buffer)
+		/* get the rb we want to redirect to */
+		rb = ring_buffer_get(output_event);
+		if (!rb)
 			goto unlock;
 	}
 
-	old_buffer = event->buffer;
-	rcu_assign_pointer(event->buffer, buffer);
+	old_rb = event->rb;
+	rcu_assign_pointer(event->rb, rb);
 	ret = 0;
 unlock:
 	mutex_unlock(&event->mmap_mutex);
 
-	if (old_buffer)
-		perf_buffer_put(old_buffer);
+	if (old_rb)
+		ring_buffer_put(old_rb);
 out:
 	return ret;
 }
@@ -6478,7 +6071,8 @@ SYSCALL_DEFINE5(perf_event_open,
 		}
 	}
 
-	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL);
+	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
+				 NULL, NULL);
 	if (IS_ERR(event)) {
 		err = PTR_ERR(event);
 		goto err_task;
@@ -6663,7 +6257,8 @@ err_fd:
 struct perf_event *
 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
 				 struct task_struct *task,
-				 perf_overflow_handler_t overflow_handler)
+				 perf_overflow_handler_t overflow_handler,
+				 void *context)
 {
 	struct perf_event_context *ctx;
 	struct perf_event *event;
@@ -6673,7 +6268,8 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
 	 * Get the target context (task or percpu):
 	 */
 
-	event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler);
+	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
+				 overflow_handler, context);
 	if (IS_ERR(event)) {
 		err = PTR_ERR(event);
 		goto err;
@@ -6780,7 +6376,6 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
 	 * our context.
 	 */
 	child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
-	task_ctx_sched_out(child_ctx, EVENT_ALL);
 
 	/*
 	 * Take the context lock here so that if find_get_context is
@@ -6788,6 +6383,7 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
 	 * incremented the context's refcount before we do put_ctx below.
 	 */
 	raw_spin_lock(&child_ctx->lock);
+	task_ctx_sched_out(child_ctx);
 	child->perf_event_ctxp[ctxn] = NULL;
 	/*
 	 * If this context is a clone; unclone it so it can't get
@@ -6957,7 +6553,7 @@ inherit_event(struct perf_event *parent_event,
 					   parent_event->cpu,
 					   child,
 					   group_leader, parent_event,
-					   NULL);
+				           NULL, NULL);
 	if (IS_ERR(child_event))
 		return child_event;
 	get_ctx(child_ctx);
@@ -6984,6 +6580,8 @@ inherit_event(struct perf_event *parent_event,
 
 	child_event->ctx = child_ctx;
 	child_event->overflow_handler = parent_event->overflow_handler;
+	child_event->overflow_handler_context
+		= parent_event->overflow_handler_context;
 
 	/*
 	 * Precalculate sample_data sizes
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index 086adf25a55e..b7971d6f38bf 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -431,9 +431,11 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
 struct perf_event *
 register_user_hw_breakpoint(struct perf_event_attr *attr,
 			    perf_overflow_handler_t triggered,
+			    void *context,
 			    struct task_struct *tsk)
 {
-	return perf_event_create_kernel_counter(attr, -1, tsk, triggered);
+	return perf_event_create_kernel_counter(attr, -1, tsk, triggered,
+						context);
 }
 EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
 
@@ -502,7 +504,8 @@ EXPORT_SYMBOL_GPL(unregister_hw_breakpoint);
  */
 struct perf_event * __percpu *
 register_wide_hw_breakpoint(struct perf_event_attr *attr,
-			    perf_overflow_handler_t triggered)
+			    perf_overflow_handler_t triggered,
+			    void *context)
 {
 	struct perf_event * __percpu *cpu_events, **pevent, *bp;
 	long err;
@@ -515,7 +518,8 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr,
 	get_online_cpus();
 	for_each_online_cpu(cpu) {
 		pevent = per_cpu_ptr(cpu_events, cpu);
-		bp = perf_event_create_kernel_counter(attr, cpu, NULL, triggered);
+		bp = perf_event_create_kernel_counter(attr, cpu, NULL,
+						      triggered, context);
 
 		*pevent = bp;
 
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
new file mode 100644
index 000000000000..09097dd8116c
--- /dev/null
+++ b/kernel/events/internal.h
@@ -0,0 +1,96 @@
+#ifndef _KERNEL_EVENTS_INTERNAL_H
+#define _KERNEL_EVENTS_INTERNAL_H
+
+#define RING_BUFFER_WRITABLE		0x01
+
+struct ring_buffer {
+	atomic_t			refcount;
+	struct rcu_head			rcu_head;
+#ifdef CONFIG_PERF_USE_VMALLOC
+	struct work_struct		work;
+	int				page_order;	/* allocation order  */
+#endif
+	int				nr_pages;	/* nr of data pages  */
+	int				writable;	/* are we writable   */
+
+	atomic_t			poll;		/* POLL_ for wakeups */
+
+	local_t				head;		/* write position    */
+	local_t				nest;		/* nested writers    */
+	local_t				events;		/* event limit       */
+	local_t				wakeup;		/* wakeup stamp      */
+	local_t				lost;		/* nr records lost   */
+
+	long				watermark;	/* wakeup watermark  */
+
+	struct perf_event_mmap_page	*user_page;
+	void				*data_pages[0];
+};
+
+extern void rb_free(struct ring_buffer *rb);
+extern struct ring_buffer *
+rb_alloc(int nr_pages, long watermark, int cpu, int flags);
+extern void perf_event_wakeup(struct perf_event *event);
+
+extern void
+perf_event_header__init_id(struct perf_event_header *header,
+			   struct perf_sample_data *data,
+			   struct perf_event *event);
+extern void
+perf_event__output_id_sample(struct perf_event *event,
+			     struct perf_output_handle *handle,
+			     struct perf_sample_data *sample);
+
+extern struct page *
+perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff);
+
+#ifdef CONFIG_PERF_USE_VMALLOC
+/*
+ * Back perf_mmap() with vmalloc memory.
+ *
+ * Required for architectures that have d-cache aliasing issues.
+ */
+
+static inline int page_order(struct ring_buffer *rb)
+{
+	return rb->page_order;
+}
+
+#else
+
+static inline int page_order(struct ring_buffer *rb)
+{
+	return 0;
+}
+#endif
+
+static unsigned long perf_data_size(struct ring_buffer *rb)
+{
+	return rb->nr_pages << (PAGE_SHIFT + page_order(rb));
+}
+
+static inline void
+__output_copy(struct perf_output_handle *handle,
+		   const void *buf, unsigned int len)
+{
+	do {
+		unsigned long size = min_t(unsigned long, handle->size, len);
+
+		memcpy(handle->addr, buf, size);
+
+		len -= size;
+		handle->addr += size;
+		buf += size;
+		handle->size -= size;
+		if (!handle->size) {
+			struct ring_buffer *rb = handle->rb;
+
+			handle->page++;
+			handle->page &= rb->nr_pages - 1;
+			handle->addr = rb->data_pages[handle->page];
+			handle->size = PAGE_SIZE << page_order(rb);
+		}
+	} while (len);
+}
+
+#endif /* _KERNEL_EVENTS_INTERNAL_H */
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
new file mode 100644
index 000000000000..a2a29205cc0f
--- /dev/null
+++ b/kernel/events/ring_buffer.c
@@ -0,0 +1,380 @@
+/*
+ * Performance events ring-buffer code:
+ *
+ *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
+ *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ *
+ * For licensing details see kernel-base/COPYING
+ */
+
+#include <linux/perf_event.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+
+#include "internal.h"
+
+static bool perf_output_space(struct ring_buffer *rb, unsigned long tail,
+			      unsigned long offset, unsigned long head)
+{
+	unsigned long mask;
+
+	if (!rb->writable)
+		return true;
+
+	mask = perf_data_size(rb) - 1;
+
+	offset = (offset - tail) & mask;
+	head   = (head   - tail) & mask;
+
+	if ((int)(head - offset) < 0)
+		return false;
+
+	return true;
+}
+
+static void perf_output_wakeup(struct perf_output_handle *handle)
+{
+	atomic_set(&handle->rb->poll, POLL_IN);
+
+	handle->event->pending_wakeup = 1;
+	irq_work_queue(&handle->event->pending);
+}
+
+/*
+ * We need to ensure a later event_id 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.
+ *
+ * We only publish the head (and generate a wakeup) when the outer-most
+ * event completes.
+ */
+static void perf_output_get_handle(struct perf_output_handle *handle)
+{
+	struct ring_buffer *rb = handle->rb;
+
+	preempt_disable();
+	local_inc(&rb->nest);
+	handle->wakeup = local_read(&rb->wakeup);
+}
+
+static void perf_output_put_handle(struct perf_output_handle *handle)
+{
+	struct ring_buffer *rb = handle->rb;
+	unsigned long head;
+
+again:
+	head = local_read(&rb->head);
+
+	/*
+	 * IRQ/NMI can happen here, which means we can miss a head update.
+	 */
+
+	if (!local_dec_and_test(&rb->nest))
+		goto out;
+
+	/*
+	 * Publish the known good head. Rely on the full barrier implied
+	 * by atomic_dec_and_test() order the rb->head read and this
+	 * write.
+	 */
+	rb->user_page->data_head = head;
+
+	/*
+	 * Now check if we missed an update, rely on the (compiler)
+	 * barrier in atomic_dec_and_test() to re-read rb->head.
+	 */
+	if (unlikely(head != local_read(&rb->head))) {
+		local_inc(&rb->nest);
+		goto again;
+	}
+
+	if (handle->wakeup != local_read(&rb->wakeup))
+		perf_output_wakeup(handle);
+
+out:
+	preempt_enable();
+}
+
+int perf_output_begin(struct perf_output_handle *handle,
+		      struct perf_event *event, unsigned int size)
+{
+	struct ring_buffer *rb;
+	unsigned long tail, offset, head;
+	int have_lost;
+	struct perf_sample_data sample_data;
+	struct {
+		struct perf_event_header header;
+		u64			 id;
+		u64			 lost;
+	} lost_event;
+
+	rcu_read_lock();
+	/*
+	 * For inherited events we send all the output towards the parent.
+	 */
+	if (event->parent)
+		event = event->parent;
+
+	rb = rcu_dereference(event->rb);
+	if (!rb)
+		goto out;
+
+	handle->rb	= rb;
+	handle->event	= event;
+
+	if (!rb->nr_pages)
+		goto out;
+
+	have_lost = local_read(&rb->lost);
+	if (have_lost) {
+		lost_event.header.size = sizeof(lost_event);
+		perf_event_header__init_id(&lost_event.header, &sample_data,
+					   event);
+		size += lost_event.header.size;
+	}
+
+	perf_output_get_handle(handle);
+
+	do {
+		/*
+		 * Userspace could choose to issue a mb() before updating the
+		 * tail pointer. So that all reads will be completed before the
+		 * write is issued.
+		 */
+		tail = ACCESS_ONCE(rb->user_page->data_tail);
+		smp_rmb();
+		offset = head = local_read(&rb->head);
+		head += size;
+		if (unlikely(!perf_output_space(rb, tail, offset, head)))
+			goto fail;
+	} while (local_cmpxchg(&rb->head, offset, head) != offset);
+
+	if (head - local_read(&rb->wakeup) > rb->watermark)
+		local_add(rb->watermark, &rb->wakeup);
+
+	handle->page = offset >> (PAGE_SHIFT + page_order(rb));
+	handle->page &= rb->nr_pages - 1;
+	handle->size = offset & ((PAGE_SIZE << page_order(rb)) - 1);
+	handle->addr = rb->data_pages[handle->page];
+	handle->addr += handle->size;
+	handle->size = (PAGE_SIZE << page_order(rb)) - handle->size;
+
+	if (have_lost) {
+		lost_event.header.type = PERF_RECORD_LOST;
+		lost_event.header.misc = 0;
+		lost_event.id          = event->id;
+		lost_event.lost        = local_xchg(&rb->lost, 0);
+
+		perf_output_put(handle, lost_event);
+		perf_event__output_id_sample(event, handle, &sample_data);
+	}
+
+	return 0;
+
+fail:
+	local_inc(&rb->lost);
+	perf_output_put_handle(handle);
+out:
+	rcu_read_unlock();
+
+	return -ENOSPC;
+}
+
+void perf_output_copy(struct perf_output_handle *handle,
+		      const void *buf, unsigned int len)
+{
+	__output_copy(handle, buf, len);
+}
+
+void perf_output_end(struct perf_output_handle *handle)
+{
+	perf_output_put_handle(handle);
+	rcu_read_unlock();
+}
+
+static void
+ring_buffer_init(struct ring_buffer *rb, long watermark, int flags)
+{
+	long max_size = perf_data_size(rb);
+
+	if (watermark)
+		rb->watermark = min(max_size, watermark);
+
+	if (!rb->watermark)
+		rb->watermark = max_size / 2;
+
+	if (flags & RING_BUFFER_WRITABLE)
+		rb->writable = 1;
+
+	atomic_set(&rb->refcount, 1);
+}
+
+#ifndef CONFIG_PERF_USE_VMALLOC
+
+/*
+ * Back perf_mmap() with regular GFP_KERNEL-0 pages.
+ */
+
+struct page *
+perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff)
+{
+	if (pgoff > rb->nr_pages)
+		return NULL;
+
+	if (pgoff == 0)
+		return virt_to_page(rb->user_page);
+
+	return virt_to_page(rb->data_pages[pgoff - 1]);
+}
+
+static void *perf_mmap_alloc_page(int cpu)
+{
+	struct page *page;
+	int node;
+
+	node = (cpu == -1) ? cpu : cpu_to_node(cpu);
+	page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+	if (!page)
+		return NULL;
+
+	return page_address(page);
+}
+
+struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+	struct ring_buffer *rb;
+	unsigned long size;
+	int i;
+
+	size = sizeof(struct ring_buffer);
+	size += nr_pages * sizeof(void *);
+
+	rb = kzalloc(size, GFP_KERNEL);
+	if (!rb)
+		goto fail;
+
+	rb->user_page = perf_mmap_alloc_page(cpu);
+	if (!rb->user_page)
+		goto fail_user_page;
+
+	for (i = 0; i < nr_pages; i++) {
+		rb->data_pages[i] = perf_mmap_alloc_page(cpu);
+		if (!rb->data_pages[i])
+			goto fail_data_pages;
+	}
+
+	rb->nr_pages = nr_pages;
+
+	ring_buffer_init(rb, watermark, flags);
+
+	return rb;
+
+fail_data_pages:
+	for (i--; i >= 0; i--)
+		free_page((unsigned long)rb->data_pages[i]);
+
+	free_page((unsigned long)rb->user_page);
+
+fail_user_page:
+	kfree(rb);
+
+fail:
+	return NULL;
+}
+
+static void perf_mmap_free_page(unsigned long addr)
+{
+	struct page *page = virt_to_page((void *)addr);
+
+	page->mapping = NULL;
+	__free_page(page);
+}
+
+void rb_free(struct ring_buffer *rb)
+{
+	int i;
+
+	perf_mmap_free_page((unsigned long)rb->user_page);
+	for (i = 0; i < rb->nr_pages; i++)
+		perf_mmap_free_page((unsigned long)rb->data_pages[i]);
+	kfree(rb);
+}
+
+#else
+
+struct page *
+perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff)
+{
+	if (pgoff > (1UL << page_order(rb)))
+		return NULL;
+
+	return vmalloc_to_page((void *)rb->user_page + pgoff * PAGE_SIZE);
+}
+
+static void perf_mmap_unmark_page(void *addr)
+{
+	struct page *page = vmalloc_to_page(addr);
+
+	page->mapping = NULL;
+}
+
+static void rb_free_work(struct work_struct *work)
+{
+	struct ring_buffer *rb;
+	void *base;
+	int i, nr;
+
+	rb = container_of(work, struct ring_buffer, work);
+	nr = 1 << page_order(rb);
+
+	base = rb->user_page;
+	for (i = 0; i < nr + 1; i++)
+		perf_mmap_unmark_page(base + (i * PAGE_SIZE));
+
+	vfree(base);
+	kfree(rb);
+}
+
+void rb_free(struct ring_buffer *rb)
+{
+	schedule_work(&rb->work);
+}
+
+struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+	struct ring_buffer *rb;
+	unsigned long size;
+	void *all_buf;
+
+	size = sizeof(struct ring_buffer);
+	size += sizeof(void *);
+
+	rb = kzalloc(size, GFP_KERNEL);
+	if (!rb)
+		goto fail;
+
+	INIT_WORK(&rb->work, rb_free_work);
+
+	all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
+	if (!all_buf)
+		goto fail_all_buf;
+
+	rb->user_page = all_buf;
+	rb->data_pages[0] = all_buf + PAGE_SIZE;
+	rb->page_order = ilog2(nr_pages);
+	rb->nr_pages = 1;
+
+	ring_buffer_init(rb, watermark, flags);
+
+	return rb;
+
+fail_all_buf:
+	kfree(rb);
+
+fail:
+	return NULL;
+}
+
+#endif