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From cf5a79a4fc58f655ef60463859926d360c048d1b Mon Sep 17 00:00:00 2001
From: Tom Zanussi <tom.zanussi@linux.intel.com>
Date: Mon, 15 Jan 2018 20:51:39 -0600
Subject: [PATCH 1753/1795] ring-buffer: Add interface for setting absolute
time stamps
Define a new function, tracing_set_time_stamp_abs(), which can be used
to enable or disable the use of absolute timestamps rather than time
deltas for a trace array.
Only the interface is added here; a subsequent patch will add the
underlying implementation.
Link: http://lkml.kernel.org/r/ce96119de44c7fe0ee44786d15254e9b493040d3.1516069914.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Baohong Liu <baohong.liu@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
(cherry picked from commit 00b4145298aeb05a2d110117ed18148cb21ebd14)
Signed-off-by: Hirotaka MOTAI <Motai.Hirotaka@aj.MitsubishiElectric.co.jp>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
include/linux/ring_buffer.h | 2 ++
kernel/trace/ring_buffer.c | 11 +++++++++++
kernel/trace/trace.c | 33 ++++++++++++++++++++++++++++++++-
kernel/trace/trace.h | 3 +++
4 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 5caa062a02b2..adffb56bae8f 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -179,6 +179,8 @@ void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
int cpu, u64 *ts);
void ring_buffer_set_clock(struct ring_buffer *buffer,
u64 (*clock)(void));
+void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs);
+bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer);
size_t ring_buffer_page_len(void *page);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 052b44d616cb..34179e57c355 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -488,6 +488,7 @@ struct ring_buffer {
u64 (*clock)(void);
struct rb_irq_work irq_work;
+ bool time_stamp_abs;
};
struct ring_buffer_iter {
@@ -1387,6 +1388,16 @@ void ring_buffer_set_clock(struct ring_buffer *buffer,
buffer->clock = clock;
}
+void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs)
+{
+ buffer->time_stamp_abs = abs;
+}
+
+bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer)
+{
+ return buffer->time_stamp_abs;
+}
+
static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer);
static inline unsigned long rb_page_entries(struct buffer_page *bpage)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index e9cbb96cd99e..0359ff7ba906 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2275,7 +2275,7 @@ trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
*current_rb = trace_file->tr->trace_buffer.buffer;
- if ((trace_file->flags &
+ if (!ring_buffer_time_stamp_abs(*current_rb) && (trace_file->flags &
(EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
(entry = this_cpu_read(trace_buffered_event))) {
/* Try to use the per cpu buffer first */
@@ -6298,6 +6298,37 @@ static int tracing_clock_open(struct inode *inode, struct file *file)
return ret;
}
+int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs)
+{
+ int ret = 0;
+
+ mutex_lock(&trace_types_lock);
+
+ if (abs && tr->time_stamp_abs_ref++)
+ goto out;
+
+ if (!abs) {
+ if (WARN_ON_ONCE(!tr->time_stamp_abs_ref)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (--tr->time_stamp_abs_ref)
+ goto out;
+ }
+
+ ring_buffer_set_time_stamp_abs(tr->trace_buffer.buffer, abs);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+ if (tr->max_buffer.buffer)
+ ring_buffer_set_time_stamp_abs(tr->max_buffer.buffer, abs);
+#endif
+ out:
+ mutex_unlock(&trace_types_lock);
+
+ return ret;
+}
+
struct ftrace_buffer_info {
struct trace_iterator iter;
void *spare;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 96c92f9c314c..5f1d4ae594e5 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -273,6 +273,7 @@ struct trace_array {
/* function tracing enabled */
int function_enabled;
#endif
+ int time_stamp_abs_ref;
};
enum {
@@ -286,6 +287,8 @@ extern struct mutex trace_types_lock;
extern int trace_array_get(struct trace_array *tr);
extern void trace_array_put(struct trace_array *tr);
+extern int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs);
+
/*
* The global tracer (top) should be the first trace array added,
* but we check the flag anyway.
--
2.19.0
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