perf: Reduce stack usage of perf_output_begin()

__perf_output_begin() has an on-stack struct perf_sample_data in the
unlikely case it needs to generate a LOST record. However, every call
to perf_output_begin() must already have a perf_sample_data on-stack.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201030151954.985416146@infradead.org
This commit is contained in:
Peter Zijlstra
2020-10-30 15:50:32 +01:00
parent 7bdb157cde
commit 267fb27352
6 changed files with 37 additions and 30 deletions

View File

@@ -1400,11 +1400,14 @@ perf_event_addr_filters(struct perf_event *event)
extern void perf_event_addr_filters_sync(struct perf_event *event);
extern int perf_output_begin(struct perf_output_handle *handle,
struct perf_sample_data *data,
struct perf_event *event, unsigned int size);
extern int perf_output_begin_forward(struct perf_output_handle *handle,
struct perf_event *event,
unsigned int size);
struct perf_sample_data *data,
struct perf_event *event,
unsigned int size);
extern int perf_output_begin_backward(struct perf_output_handle *handle,
struct perf_sample_data *data,
struct perf_event *event,
unsigned int size);