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authorPeter Zijlstra <peterz@infradead.org>2016-03-18 16:28:04 +0100
committerSteven Rostedt <rostedt@goodmis.org>2016-03-22 23:04:10 +0100
commit7e6867bf831c71fe0e47438831ae3a94d4c7ab3c (patch)
treeaff6902663d850f314a23900a8caebf9a78e2a86 /kernel
parenttracing: Fix trace_printk() to print when not using bprintk() (diff)
downloadlinux-7e6867bf831c71fe0e47438831ae3a94d4c7ab3c.tar.xz
linux-7e6867bf831c71fe0e47438831ae3a94d4c7ab3c.zip
tracing: Record and show NMI state
The latency tracer format has a nice column to indicate IRQ state, but this is not able to tell us about NMI state. When tracing perf interrupt handlers (which often run in NMI context) it is very useful to see how the events nest. Link: http://lkml.kernel.org/r/20160318153022.105068893@infradead.org Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c1
-rw-r--r--kernel/trace/trace.h1
-rw-r--r--kernel/trace/trace_output.c10
3 files changed, 9 insertions, 3 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index cb2b708e4ea7..7bdf8ba323ec 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1664,6 +1664,7 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
#else
TRACE_FLAG_IRQS_NOSUPPORT |
#endif
+ ((pc & NMI_MASK ) ? TRACE_FLAG_NMI : 0) |
((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 39588c23dd8b..3fff4adfd431 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -125,6 +125,7 @@ enum trace_flag_type {
TRACE_FLAG_HARDIRQ = 0x08,
TRACE_FLAG_SOFTIRQ = 0x10,
TRACE_FLAG_PREEMPT_RESCHED = 0x20,
+ TRACE_FLAG_NMI = 0x40,
};
#define TRACE_BUF_SIZE 1024
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 282982195e09..0bb9cf2d53e6 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -389,7 +389,9 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
char irqs_off;
int hardirq;
int softirq;
+ int nmi;
+ nmi = entry->flags & TRACE_FLAG_NMI;
hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
@@ -415,10 +417,12 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
}
hardsoft_irq =
+ (nmi && hardirq) ? 'Z' :
+ nmi ? 'z' :
(hardirq && softirq) ? 'H' :
- hardirq ? 'h' :
- softirq ? 's' :
- '.';
+ hardirq ? 'h' :
+ softirq ? 's' :
+ '.' ;
trace_seq_printf(s, "%c%c%c",
irqs_off, need_resched, hardsoft_irq);