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authorIan Rogers <irogers@google.com>2024-02-10 06:17:46 +0300
committerNamhyung Kim <namhyung@kernel.org>2024-02-12 23:35:41 +0300
commit923e4616ec15b7feabdc353b229762069eb73c43 (patch)
tree6f9d5e861d27560f0ba58a98cd191924abc6546f
parentff0bd79980fffa00c36eb2b9044dbe9cfdf4bb79 (diff)
downloadlinux-923e4616ec15b7feabdc353b229762069eb73c43.tar.xz
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@google.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: K Prateek Nayak <kprateek.nayak@amd.com> Cc: James Clark <james.clark@arm.com> Cc: Vincent Whitchurch <vincent.whitchurch@axis.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Colin Ian King <colin.i.king@gmail.com> Cc: Changbin Du <changbin.du@huawei.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Leo Yan <leo.yan@linux.dev> Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Artem Savkov <asavkov@redhat.com> Cc: bpf@vger.kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> Link: https://lore.kernel.org/r/20240210031746.4057262-7-irogers@google.com
-rw-r--r--tools/perf/util/machine.c2
-rw-r--r--tools/perf/util/maps.c10
-rw-r--r--tools/perf/util/maps.h4
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);