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authorPeter Zijlstra <peterz@infradead.org>2013-10-04 17:28:26 +0200
committerIngo Molnar <mingo@kernel.org>2013-11-11 12:43:39 +0100
commite5137b50a0640009fd63a3e65c14bc6e1be8796a (patch)
treeef8475a7281a78d7ad7bd6694b44c8a32c12f970
parent7053ea1a34fa8567cb5e3c39e04ace4c5d0fbeaa (diff)
ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHED
Since the introduction of PREEMPT_NEED_RESCHED in: f27dde8deef3 ("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: Peter Zijlstra <peterz@infradead.org> Acked-by: Steven 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: Ingo Molnar <mingo@kernel.org>
-rw-r--r--Documentation/trace/ftrace.txt6
-rw-r--r--kernel/trace/trace.c3
-rw-r--r--kernel/trace/trace.h1
-rw-r--r--kernel/trace/trace_output.c19
4 files changed, 25 insertions, 4 deletions
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index ea2d35d64d26..bd365988e8d8 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -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.
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7974ba20557d..d9fea7dfd5d3 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 10c86fb7a2b4..73d08aa25b55 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -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
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 34e7cbac0c9c..ed32284fbe32 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -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' :