linux-kernel - [PATCH 15/25] perf tools: Allow mmap2 event to synthesize modules

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Date:   Thu, 26 Nov 2020 18:00:16 +0100
From:   Jiri Olsa <jolsa@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Ian Rogers <irogers@...gle.com>,
        lkml <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Ingo Molnar <mingo@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Michael Petlan <mpetlan@...hat.com>,
        Song Liu <songliubraving@...com>,
        Stephane Eranian <eranian@...gle.com>,
        Alexey Budankov <alexey.budankov@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>
Subject: [PATCH 15/25] perf tools: Allow mmap2 event to synthesize modules

Allow mmap2 event to synthesize kernel modules,
so we can synthesize module's build id data in
following changes.

It's enabled by new symbol_conf.buildid_mmap2
bool, which will be switched in following
changes.

Acked-by: Ian Rogers <irogers@...gle.com>
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 tools/perf/util/synthetic-events.c | 49 +++++++++++++++++++-----------
 1 file changed, 32 insertions(+), 17 deletions(-)

diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index 872df6d6dbef..a18ae502d765 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -593,16 +593,17 @@ int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t
 	int rc = 0;
 	struct map *pos;
 	struct maps *maps = machine__kernel_maps(machine);
-	union perf_event *event = zalloc((sizeof(event->mmap) +
-					  machine->id_hdr_size));
+	union perf_event *event;
+	size_t size = symbol_conf.buildid_mmap2 ?
+			sizeof(event->mmap2) : sizeof(event->mmap);
+
+	event = zalloc(size + machine->id_hdr_size);
 	if (event == NULL) {
 		pr_debug("Not enough memory synthesizing mmap event "
 			 "for kernel modules\n");
 		return -1;
 	}
 
-	event->header.type = PERF_RECORD_MMAP;
-
 	/*
 	 * kernel uses 0 for user space maps, see kernel/perf_event.c
 	 * __perf_event_mmap
@@ -613,23 +614,37 @@ int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t
 		event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
 
 	maps__for_each_entry(maps, pos) {
-		size_t size;
-
 		if (!__map__is_kmodule(pos))
 			continue;
 
-		size = PERF_ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
-		event->mmap.header.type = PERF_RECORD_MMAP;
-		event->mmap.header.size = (sizeof(event->mmap) -
-				        (sizeof(event->mmap.filename) - size));
-		memset(event->mmap.filename + size, 0, machine->id_hdr_size);
-		event->mmap.header.size += machine->id_hdr_size;
-		event->mmap.start = pos->start;
-		event->mmap.len   = pos->end - pos->start;
-		event->mmap.pid   = machine->pid;
+		if (symbol_conf.buildid_mmap2) {
+			size = PERF_ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
+			event->mmap2.header.type = PERF_RECORD_MMAP2;
+			event->mmap2.header.size = (sizeof(event->mmap2) -
+						(sizeof(event->mmap2.filename) - size));
+			memset(event->mmap2.filename + size, 0, machine->id_hdr_size);
+			event->mmap2.header.size += machine->id_hdr_size;
+			event->mmap2.start = pos->start;
+			event->mmap2.len   = pos->end - pos->start;
+			event->mmap2.pid   = machine->pid;
+
+			memcpy(event->mmap2.filename, pos->dso->long_name,
+			       pos->dso->long_name_len + 1);
+		} else {
+			size = PERF_ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
+			event->mmap.header.type = PERF_RECORD_MMAP;
+			event->mmap.header.size = (sizeof(event->mmap) -
+						(sizeof(event->mmap.filename) - size));
+			memset(event->mmap.filename + size, 0, machine->id_hdr_size);
+			event->mmap.header.size += machine->id_hdr_size;
+			event->mmap.start = pos->start;
+			event->mmap.len   = pos->end - pos->start;
+			event->mmap.pid   = machine->pid;
+
+			memcpy(event->mmap.filename, pos->dso->long_name,
+			       pos->dso->long_name_len + 1);
+		}
 
-		memcpy(event->mmap.filename, pos->dso->long_name,
-		       pos->dso->long_name_len + 1);
 		if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
 			rc = -1;
 			break;
-- 
2.26.2