From 923e4616ec15b7feabdc353b229762069eb73c43 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Fri, 9 Feb 2024 19:17:46 -0800 Subject: [PATCH] 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 Acked-by: Namhyung Kim Cc: K Prateek Nayak Cc: James Clark Cc: Vincent Whitchurch Cc: Alexey Dobriyan Cc: Colin Ian King Cc: Changbin Du Cc: Masami Hiramatsu Cc: Song Liu Cc: Leo Yan Cc: Athira Rajeev Cc: Liam Howlett Cc: Artem Savkov Cc: bpf@vger.kernel.org Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240210031746.4057262-7-irogers@google.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 439cefab112a..53aea6d2ef93 100644 --- a/tools/perf/util/maps.c +++ b/tools/perf/util/maps.c @@ -541,7 +541,13 @@ 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) @@ -871,7 +877,7 @@ 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); -- 2.25.1