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Message-Id: <20240103050635.391888-7-irogers@google.com>
Date: Tue, 2 Jan 2024 21:06:16 -0800
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>, Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>,
Adrian Hunter <adrian.hunter@...el.com>, Nick Terrell <terrelln@...com>,
Kan Liang <kan.liang@...ux.intel.com>, Andi Kleen <ak@...ux.intel.com>,
Kajol Jain <kjain@...ux.ibm.com>, Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
Huacai Chen <chenhuacai@...nel.org>, Masami Hiramatsu <mhiramat@...nel.org>,
Vincent Whitchurch <vincent.whitchurch@...s.com>, "Steinar H. Gunderson" <sesse@...gle.com>,
Liam Howlett <liam.howlett@...cle.com>, Miguel Ojeda <ojeda@...nel.org>,
Colin Ian King <colin.i.king@...il.com>, Dmitrii Dolgov <9erthalion6@...il.com>,
Yang Jihong <yangjihong1@...wei.com>, Ming Wang <wangming01@...ngson.cn>,
James Clark <james.clark@....com>, K Prateek Nayak <kprateek.nayak@....com>,
Sean Christopherson <seanjc@...gle.com>, Leo Yan <leo.yan@...aro.org>,
Ravi Bangoria <ravi.bangoria@....com>, German Gomez <german.gomez@....com>,
Changbin Du <changbin.du@...wei.com>, Paolo Bonzini <pbonzini@...hat.com>, Li Dong <lidong@...o.com>,
Sandipan Das <sandipan.das@....com>, liuwenyu <liuwenyu7@...wei.com>,
linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
Guilherme Amadio <amadio@...too.org>
Subject: [PATCH v7 06/25] perf maps: Locking tidy up of nr_maps
After this change maps__nr_maps is only used by tests, existing users
are migrated to maps__empty. Compute maps__empty under the read lock.
Signed-off-by: Ian Rogers <irogers@...gle.com>
---
tools/perf/util/machine.c | 2 +-
tools/perf/util/maps.c | 10 ++++++++--
tools/perf/util/maps.h | 4 ++--
3 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 4911734411b5..3da92f18814a 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -440,7 +440,7 @@ static struct thread *findnew_guest_code(struct machine *machine,
return NULL;
/* Assume maps are set up if there are any */
- if (maps__nr_maps(thread__maps(thread)))
+ if (!maps__empty(thread__maps(thread)))
return thread;
host_thread = machine__find_thread(host_machine, -1, pid);
diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
index c08e412a4313..cb52de9d6c2a 100644
--- a/tools/perf/util/maps.c
+++ b/tools/perf/util/maps.c
@@ -528,7 +528,13 @@ void maps__remove(struct maps *maps, struct map *map)
bool maps__empty(struct maps *maps)
{
- return maps__nr_maps(maps) == 0;
+ bool res;
+
+ down_read(maps__lock(maps));
+ res = maps__nr_maps(maps) == 0;
+ up_read(maps__lock(maps));
+
+ return res;
}
bool maps__equal(struct maps *a, struct maps *b)
@@ -852,7 +858,7 @@ int maps__copy_from(struct maps *dest, struct maps *parent)
parent_maps_by_address = maps__maps_by_address(parent);
n = maps__nr_maps(parent);
- if (maps__empty(dest)) {
+ if (maps__nr_maps(dest) == 0) {
/* No existing mappings so just copy from parent to avoid reallocs in insert. */
unsigned int nr_maps_allocated = RC_CHK_ACCESS(parent)->nr_maps_allocated;
struct map **dest_maps_by_address =
diff --git a/tools/perf/util/maps.h b/tools/perf/util/maps.h
index 4bcba136ffe5..d9aa62ed968a 100644
--- a/tools/perf/util/maps.h
+++ b/tools/perf/util/maps.h
@@ -43,8 +43,8 @@ int maps__for_each_map(struct maps *maps, int (*cb)(struct map *map, void *data)
void maps__remove_maps(struct maps *maps, bool (*cb)(struct map *map, void *data), void *data);
struct machine *maps__machine(const struct maps *maps);
-unsigned int maps__nr_maps(const struct maps *maps);
-refcount_t *maps__refcnt(struct maps *maps);
+unsigned int maps__nr_maps(const struct maps *maps); /* Test only. */
+refcount_t *maps__refcnt(struct maps *maps); /* Test only. */
#ifdef HAVE_LIBUNWIND_SUPPORT
void *maps__addr_space(const struct maps *maps);
--
2.43.0.472.g3155946c3a-goog
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