Commit 892d00fb authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

perf inject: Lazily allocate guest_event event_buf 



The event_buf is 64kb (PERF_SAMPLE_SIZE_MAX) and stack allocated in
struct perf_inject. It is used for guest events that may not exist in
a file. Make the array allocation lazy to cut down on the stack usage.

Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230527034324.2597593-5-irogers@google.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent d3944f0e

tools/perf/builtin-inject.c

+12 −3
Original line number Diff line number Diff line
@@ -47,7 +47,7 @@ 
struct guest_event {

	struct perf_sample		sample;

	union perf_event		*event;

	char				event_buf[PERF_SAMPLE_MAX_SIZE];

	char				*event_buf;

};



struct guest_id {
@@ -1374,11 +1374,19 @@ static void guest_session__convert_time(struct guest_session *gs, u64 guest_time 


static int guest_session__fetch(struct guest_session *gs)

{

	void *buf = gs->ev.event_buf;

	struct perf_event_header *hdr = buf;

	void *buf;

	struct perf_event_header *hdr;

	size_t hdr_sz = sizeof(*hdr);

	ssize_t ret;



	buf = gs->ev.event_buf;

	if (!buf) {

		buf = malloc(PERF_SAMPLE_MAX_SIZE);

		if (!buf)

			return -ENOMEM;

		gs->ev.event_buf = buf;

	}

	hdr = buf;

	ret = readn(gs->tmp_fd, buf, hdr_sz);

	if (ret < 0)

		return ret;
@@ -2401,5 +2409,6 @@ int cmd_inject(int argc, const char **argv) 
		perf_data__close(&inject.output);

	free(inject.itrace_synth_opts.vm_tm_corr_args);

	free(inject.event_copy);

	free(inject.guest_session.ev.event_buf);

	return ret;

}