Commit-ID: 02f726949f2be0967aa4871dd4e47d3967779b26
Gitweb: http://git.kernel.org/tip/02f726949f2be0967aa4871dd4e47d3967779b26
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Mon, 31 May 2010 18:13:25 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Tue, 1 Jun 2010 09:27:17 +0200
sched, trace: Fix sched_switch() prev_state argument
For CONFIG_PREEMPT=y kernels the sched_switch(.prev_state) argument isn't
useful because we can get preempted with current->state != TASK_RUNNING
without actually getting removed from the runqueue.
Cure this by treating all preempted tasks as runnable from the tracer's
point of view.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cautiously-acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
LKML-Reference: <1275322715.27810.23323.camel@twins>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
include/trace/events/sched.h | 19 ++++++++++++++++++-
1 files changed, 18 insertions(+), 1 deletions(-)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 4f733ec..b9e1dd6 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -115,6 +115,23 @@ DEFINE_EVENT(sched_wakeup_template, sched_wakeup_new,
TP_PROTO(struct task_struct *p, int success),
TP_ARGS(p, success));
+#ifdef CREATE_TRACE_POINTS
+static inline long __trace_sched_switch_state(struct task_struct *p)
+{
+ long state = p->state;
+
+#ifdef CONFIG_PREEMPT
+ /*
+ * For all intents and purposes a preempted task is a running task.
+ */
+ if (task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)
+ state = TASK_RUNNING;
+#endif
+
+ return state;
+}
+#endif
+
/*
* Tracepoint for task switches, performed by the scheduler:
*/
@@ -139,7 +156,7 @@ TRACE_EVENT(sched_switch,
memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
__entry->prev_pid = prev->pid;
__entry->prev_prio = prev->prio;
- __entry->prev_state = prev->state;
+ __entry->prev_state = __trace_sched_switch_state(prev);
memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
__entry->next_pid = next->pid;
__entry->next_prio = next->prio;
--
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