Merge branch 'perf-fixes-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip

* 'perf-fixes-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip:
  x86, perf: Check that current->mm is alive before getting user callchain
  perf_event: Fix broken calc_timer_values()
  perf events: Fix slow and broken cgroup context switch code

2 files changed, 56 insertions, 13 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index b8785e26ee1c..0f857782d06f 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -399,14 +399,54 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
         local_irq_restore(flags);
 }
 
-static inline void perf_cgroup_sched_out(struct task_struct *task)
+static inline void perf_cgroup_sched_out(struct task_struct *task,
+                                         struct task_struct *next)
 {
-        perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
+        struct perf_cgroup *cgrp1;
+        struct perf_cgroup *cgrp2 = NULL;
+
+        /*
+         * we come here when we know perf_cgroup_events > 0
+         */
+        cgrp1 = perf_cgroup_from_task(task);
+
+        /*
+         * next is NULL when called from perf_event_enable_on_exec()
+         * that will systematically cause a cgroup_switch()
+         */
+        if (next)
+                cgrp2 = perf_cgroup_from_task(next);
+
+        /*
+         * only schedule out current cgroup events if we know
+         * that we are switching to a different cgroup. Otherwise,
+         * do no touch the cgroup events.
+         */
+        if (cgrp1 != cgrp2)
+                perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
 }
 
-static inline void perf_cgroup_sched_in(struct task_struct *task)
+static inline void perf_cgroup_sched_in(struct task_struct *prev,
+                                        struct task_struct *task)
 {
-        perf_cgroup_switch(task, PERF_CGROUP_SWIN);
+        struct perf_cgroup *cgrp1;
+        struct perf_cgroup *cgrp2 = NULL;
+
+        /*
+         * we come here when we know perf_cgroup_events > 0
+         */
+        cgrp1 = perf_cgroup_from_task(task);
+
+        /* prev can never be NULL */
+        cgrp2 = perf_cgroup_from_task(prev);
+
+        /*
+         * only need to schedule in cgroup events if we are changing
+         * cgroup during ctxsw. Cgroup events were not scheduled
+         * out of ctxsw out if that was not the case.
+         */
+        if (cgrp1 != cgrp2)
+                perf_cgroup_switch(task, PERF_CGROUP_SWIN);
 }
 
 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
@@ -518,11 +558,13 @@ static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
 {
 }
 
-static inline void perf_cgroup_sched_out(struct task_struct *task)
+static inline void perf_cgroup_sched_out(struct task_struct *task,
+                                         struct task_struct *next)
 {
 }
 
-static inline void perf_cgroup_sched_in(struct task_struct *task)
+static inline void perf_cgroup_sched_in(struct task_struct *prev,
+                                        struct task_struct *task)
 {
 }
 
@@ -1988,7 +2030,7 @@ void __perf_event_task_sched_out(struct task_struct *task,
          * cgroup event are system-wide mode only
          */
         if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
-                perf_cgroup_sched_out(task);
+                perf_cgroup_sched_out(task, next);
 }
 
 static void task_ctx_sched_out(struct perf_event_context *ctx)
@@ -2153,7 +2195,8 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
  * accessing the event control register. If a NMI hits, then it will
  * keep the event running.
  */
-void __perf_event_task_sched_in(struct task_struct *task)
+void __perf_event_task_sched_in(struct task_struct *prev,
+                                struct task_struct *task)
 {
         struct perf_event_context *ctx;
         int ctxn;
@@ -2171,7 +2214,7 @@ void __perf_event_task_sched_in(struct task_struct *task)
          * cgroup event are system-wide mode only
          */
         if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
-                perf_cgroup_sched_in(task);
+                perf_cgroup_sched_in(prev, task);
 }
 
 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
@@ -2427,7 +2470,7 @@ static void perf_event_enable_on_exec(struct perf_event_context *ctx)
          * ctxswin cgroup events which are already scheduled
          * in.
          */
-        perf_cgroup_sched_out(current);
+        perf_cgroup_sched_out(current, NULL);
 
         raw_spin_lock(&ctx->lock);
         task_ctx_sched_out(ctx);
@@ -3353,8 +3396,8 @@ static int perf_event_index(struct perf_event *event)
 }
 
 static void calc_timer_values(struct perf_event *event,
-                                u64 *running,
-                                u64 *enabled)
+                                u64 *enabled,
+                                u64 *running)
 {
         u64 now, ctx_time;
 
diff --git a/kernel/sched.c b/kernel/sched.c
index ccacdbdecf45..0408cdc6d572 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3065,7 +3065,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
         local_irq_disable();
 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
-        perf_event_task_sched_in(current);
+        perf_event_task_sched_in(prev, current);
 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
         local_irq_enable();
 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */