116 lines
3.6 KiB
Diff
116 lines
3.6 KiB
Diff
From: Tom Zanussi <tom.zanussi@linux.intel.com>
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Date: Mon, 26 Jun 2017 17:49:04 -0500
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Subject: [PATCH 03/32] ring-buffer: Add interface for setting absolute time
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stamps
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patches-4.11.8-rt5.tar.xz
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Define a new function, tracing_set_time_stamp_abs(), which can be used
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to enable or disable the use of absolute timestamps rather than time
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deltas for a trace array.
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This resets the buffer to prevent a mix of time deltas and absolute
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timestamps.
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Only the interface is added here; a subsequent patch will add the
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underlying implementation.
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Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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include/linux/ring_buffer.h | 2 ++
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kernel/trace/ring_buffer.c | 11 +++++++++++
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kernel/trace/trace.c | 25 ++++++++++++++++++++++++-
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kernel/trace/trace.h | 2 ++
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4 files changed, 39 insertions(+), 1 deletion(-)
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--- a/include/linux/ring_buffer.h
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+++ b/include/linux/ring_buffer.h
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@@ -180,6 +180,8 @@ void ring_buffer_normalize_time_stamp(st
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int cpu, u64 *ts);
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void ring_buffer_set_clock(struct ring_buffer *buffer,
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u64 (*clock)(void));
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+void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs);
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+bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer);
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size_t ring_buffer_page_len(void *page);
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--- a/kernel/trace/ring_buffer.c
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+++ b/kernel/trace/ring_buffer.c
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@@ -484,6 +484,7 @@ struct ring_buffer {
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u64 (*clock)(void);
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struct rb_irq_work irq_work;
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+ bool time_stamp_abs;
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};
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struct ring_buffer_iter {
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@@ -1378,6 +1379,16 @@ void ring_buffer_set_clock(struct ring_b
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buffer->clock = clock;
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}
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+void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs)
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+{
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+ buffer->time_stamp_abs = abs;
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+}
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+
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+bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer)
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+{
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+ return buffer->time_stamp_abs;
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+}
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+
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static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer);
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static inline unsigned long rb_page_entries(struct buffer_page *bpage)
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--- a/kernel/trace/trace.c
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+++ b/kernel/trace/trace.c
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@@ -2082,7 +2082,7 @@ trace_event_buffer_lock_reserve(struct r
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*current_rb = trace_file->tr->trace_buffer.buffer;
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- if ((trace_file->flags &
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+ if (!ring_buffer_time_stamp_abs(*current_rb) && (trace_file->flags &
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(EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
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(entry = this_cpu_read(trace_buffered_event))) {
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/* Try to use the per cpu buffer first */
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@@ -5959,6 +5959,29 @@ static int tracing_clock_open(struct ino
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return ret;
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}
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+int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs)
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+{
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+ mutex_lock(&trace_types_lock);
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+
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+ ring_buffer_set_time_stamp_abs(tr->trace_buffer.buffer, abs);
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+
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+ /*
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+ * New timestamps may not be consistent with the previous setting.
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+ * Reset the buffer so that it doesn't have incomparable timestamps.
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+ */
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+ tracing_reset_online_cpus(&tr->trace_buffer);
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+
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+#ifdef CONFIG_TRACER_MAX_TRACE
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+ if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
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+ ring_buffer_set_time_stamp_abs(tr->max_buffer.buffer, abs);
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+ tracing_reset_online_cpus(&tr->max_buffer);
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+#endif
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+
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+ mutex_unlock(&trace_types_lock);
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+
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+ return 0;
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+}
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+
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struct ftrace_buffer_info {
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struct trace_iterator iter;
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void *spare;
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--- a/kernel/trace/trace.h
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+++ b/kernel/trace/trace.h
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@@ -278,6 +278,8 @@ extern struct mutex trace_types_lock;
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extern int trace_array_get(struct trace_array *tr);
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extern void trace_array_put(struct trace_array *tr);
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+extern int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs);
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+
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/*
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* The global tracer (top) should be the first trace array added,
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* but we check the flag anyway.
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