From 892d00fba18a6dec2620165ce05e1697496f8381 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Fri, 26 May 2023 20:43:22 -0700 Subject: [PATCH] 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: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20230527034324.2597593-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-inject.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c index 2023b7a..c8cf2fdd 100644 --- a/tools/perf/builtin-inject.c +++ b/tools/perf/builtin-inject.c @@ -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; } -- 2.7.4