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tracing: Add method for recording "func_repeats" events

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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: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Yordan Karadzhov (VMware) 2021-04-15 21:18:52 +03:00 committed by Steven Rostedt (VMware)
parent 20344c54d1
commit c658797f1a
2 changed files with 38 additions and 0 deletions
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34
kernel/trace/trace.c
View File

@ -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;

4
kernel/trace/trace.h
View File

@ -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[]);