[tip:sched/urgent] sched, trace: Fix sched_switch() prev_state argument
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From: tip-bot for Peter Zijlstra on 1 Jun 2010 05:20 Commit-ID: 02f726949f2be0967aa4871dd4e47d3967779b26 Gitweb: http://git.kernel.org/tip/02f726949f2be0967aa4871dd4e47d3967779b26 Author: Peter Zijlstra <a.p.zijlstra(a)chello.nl> AuthorDate: Mon, 31 May 2010 18:13:25 +0200 Committer: Ingo Molnar <mingo(a)elte.hu> 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(a)chello.nl> Cautiously-acked-by: Steven Rostedt <rostedt(a)goodmis.org> LKML-Reference: <1275322715.27810.23323.camel(a)twins> Signed-off-by: Ingo Molnar <mingo(a)elte.hu> --- 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |