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Commit e5137b50 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHED 



Since the introduction of PREEMPT_NEED_RESCHED in:

  f27dde8d ("sched: Add NEED_RESCHED to the preempt_count")

we need to be able to look at both TIF_NEED_RESCHED and
PREEMPT_NEED_RESCHED to understand the full preemption behaviour.

Add it to the trace output.

Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Link: http://lkml.kernel.org/r/20131004152826.GP3081@twins.programming.kicks-ass.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7053ea1a

Documentation/trace/ftrace.txt

+5 −1
Original line number Diff line number Diff line
@@ -655,7 +655,11 @@ explains which is which. 
		  read the irq flags variable, an 'X' will always

		  be printed here.



  need-resched: 'N' task need_resched is set, '.' otherwise.

  need-resched:

	'N' both TIF_NEED_RESCHED and PREEMPT_NEED_RESCHED is set,

	'n' only TIF_NEED_RESCHED is set,

	'p' only PREEMPT_NEED_RESCHED is set,

	'.' otherwise.



  hardirq/softirq:

	'H' - hard irq occurred inside a softirq.

kernel/trace/trace.c

+2 −1
Original line number Diff line number Diff line
@@ -1509,7 +1509,8 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags, 
#endif

		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |

		((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |

		(need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);

		(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |

		(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);

}

EXPORT_SYMBOL_GPL(tracing_generic_entry_update);

kernel/trace/trace.h

+1 −0
Original line number Diff line number Diff line
@@ -124,6 +124,7 @@ enum trace_flag_type { 
	TRACE_FLAG_NEED_RESCHED		= 0x04,

	TRACE_FLAG_HARDIRQ		= 0x08,

	TRACE_FLAG_SOFTIRQ		= 0x10,

	TRACE_FLAG_PREEMPT_RESCHED	= 0x20,

};



#define TRACE_BUF_SIZE		1024

kernel/trace/trace_output.c

+17 −2
Original line number Diff line number Diff line
@@ -618,8 +618,23 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry) 
		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :

		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :

		'.';

	need_resched =

		(entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.';



	switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |

				TRACE_FLAG_PREEMPT_RESCHED)) {

	case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED:

		need_resched = 'N';

		break;

	case TRACE_FLAG_NEED_RESCHED:

		need_resched = 'n';

		break;

	case TRACE_FLAG_PREEMPT_RESCHED:

		need_resched = 'p';

		break;

	default:

		need_resched = '.';

		break;

	}



	hardsoft_irq =

		(hardirq && softirq) ? 'H' :

		hardirq ? 'h' :