Commit c658797f authored by Yordan Karadzhov (VMware)'s avatar Yordan Karadzhov (VMware) Committed by Steven Rostedt (VMware)
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tracing: Add method for recording "func_repeats" events 

This patch only provides the implementation of the method.
Later we will used it in a combination with a new option for
function tracing.

Link: https://lkml.kernel.org/r/20210415181854.147448-5-y.karadz@gmail.com



Signed-off-by: default avatarYordan Karadzhov (VMware) <y.karadz@gmail.com>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 20344c54

kernel/trace/trace.c

+34 −0
Original line number Diff line number Diff line
@@ -3117,6 +3117,40 @@ static void ftrace_trace_userstack(struct trace_array *tr, 


#endif /* CONFIG_STACKTRACE */



static inline void

func_repeats_set_delta_ts(struct func_repeats_entry *entry,

			  unsigned long long delta)

{

	entry->bottom_delta_ts = delta & U32_MAX;

	entry->top_delta_ts = (delta >> 32);

}



void trace_last_func_repeats(struct trace_array *tr,

			     struct trace_func_repeats *last_info,

			     unsigned int trace_ctx)

{

	struct trace_buffer *buffer = tr->array_buffer.buffer;

	struct func_repeats_entry *entry;

	struct ring_buffer_event *event;

	u64 delta;



	event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS,

					    sizeof(*entry), trace_ctx);

	if (!event)

		return;



	delta = ring_buffer_event_time_stamp(buffer, event) -

		last_info->ts_last_call;



	entry = ring_buffer_event_data(event);

	entry->ip = last_info->ip;

	entry->parent_ip = last_info->parent_ip;

	entry->count = last_info->count;

	func_repeats_set_delta_ts(entry, delta);



	__buffer_unlock_commit(buffer, event);

}



/* created for use with alloc_percpu */

struct trace_buffer_struct {

	int nesting;

kernel/trace/trace.h

+4 −0
Original line number Diff line number Diff line
@@ -695,6 +695,10 @@ static inline void __trace_stack(struct trace_array *tr, unsigned int trace_ctx, 
}

#endif /* CONFIG_STACKTRACE */



void trace_last_func_repeats(struct trace_array *tr,

			     struct trace_func_repeats *last_info,

			     unsigned int trace_ctx);



extern u64 ftrace_now(int cpu);



extern void trace_find_cmdline(int pid, char comm[]);