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perf inject: Lazily allocate guest_event event_buf

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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: Ian 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers 2023-05-26 20:43:22 -07:00 committed by Arnaldo Carvalho de Melo
parent d3944f0ed4
commit 892d00fba1
1 changed files with 12 additions and 3 deletions
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15
tools/perf/builtin-inject.c
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@ -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 @@ out_close_output:
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;
}