jump label: Introduce static_branch() interface

[deliverable/linux.git] / kernel / perf_event.c

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index ed253aa24ba491d5861671aeedb636a9a9ad8a55..d665e92fbd44078a824fbe16232d25edaf52eee5 100644 (file)
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -125,7 +125,7 @@ enum event_type_t {
  * perf_sched_events : >0 events exist
  * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
  */
-atomic_t perf_sched_events __read_mostly;
+struct jump_label_key perf_sched_events __read_mostly;
 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
 
 static atomic_t nr_mmap_events __read_mostly;
@@ -145,7 +145,8 @@ static struct srcu_struct pmus_srcu;
  */
 int sysctl_perf_event_paranoid __read_mostly = 1;
 
-int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
+/* Minimum for 128 pages + 1 for the user control page */
+int sysctl_perf_event_mlock __read_mostly = 516; /* 'free' kb per user */
 
 /*
  * max perf event sample rate
@@ -941,6 +942,7 @@ static void perf_group_attach(struct perf_event *event)
 static void
 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
 {
+       struct perf_cpu_context *cpuctx;
        /*
         * We can have double detach due to exit/hot-unplug + close.
         */
@@ -949,8 +951,17 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
 
        event->attach_state &= ~PERF_ATTACH_CONTEXT;
 
-       if (is_cgroup_event(event))
+       if (is_cgroup_event(event)) {
                ctx->nr_cgroups--;
+               cpuctx = __get_cpu_context(ctx);
+               /*
+                * if there are no more cgroup events
+                * then cler cgrp to avoid stale pointer
+                * in update_cgrp_time_from_cpuctx()
+                */
+               if (!ctx->nr_cgroups)
+                       cpuctx->cgrp = NULL;
+       }
 
        ctx->nr_events--;
        if (event->attr.inherit_stat)
@@ -5122,7 +5133,7 @@ static int perf_exclude_event(struct perf_event *event,
                              struct pt_regs *regs)
 {
        if (event->hw.state & PERF_HES_STOPPED)
-               return 0;
+               return 1;
 
        if (regs) {
                if (event->attr.exclude_user && user_mode(regs))
@@ -5406,7 +5417,7 @@ fail:
        return err;
 }
 
-atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
+struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
 
 static void sw_perf_event_destroy(struct perf_event *event)
 {
@@ -5478,6 +5489,8 @@ static int perf_tp_event_match(struct perf_event *event,
                                struct perf_sample_data *data,
                                struct pt_regs *regs)
 {
+       if (event->hw.state & PERF_HES_STOPPED)
+               return 0;
        /*
         * All tracepoints are from kernel-space.
         */
@@ -6720,17 +6733,20 @@ __perf_event_exit_task(struct perf_event *child_event,
                         struct perf_event_context *child_ctx,
                         struct task_struct *child)
 {
-       struct perf_event *parent_event;
+       if (child_event->parent) {
+               raw_spin_lock_irq(&child_ctx->lock);
+               perf_group_detach(child_event);
+               raw_spin_unlock_irq(&child_ctx->lock);
+       }
 
        perf_remove_from_context(child_event);
 
-       parent_event = child_event->parent;
        /*
-        * It can happen that parent exits first, and has events
+        * It can happen that the parent exits first, and has events
         * that are still around due to the child reference. These
-        * events need to be zapped - but otherwise linger.
+        * events need to be zapped.
         */
-       if (parent_event) {
+       if (child_event->parent) {
                sync_child_event(child_event, child);
                free_event(child_event);
        }