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authorIan Rogers <[email protected]>2023-12-06 17:16:53 -0800
committerArnaldo Carvalho de Melo <[email protected]>2023-12-20 14:56:10 -0300
commite77b0236cd0cd1572c6a9b25097b207eab799e74 (patch)
treef5a696d86e7d54804b39f6b817559549ee1545f1
parent9084952704ba075de28684301ec282b6626b5e7a (diff)
perf maps: Add maps__load_first()
Avoid bpf_lock_contention_read touching the internal maps data structure by adding a helper function. As access is done directly on the map in maps, hold the read lock to stop it being removed. Signed-off-by: Ian Rogers <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Athira Rajeev <[email protected]> Cc: Changbin Du <[email protected]> Cc: Colin Ian King <[email protected]> Cc: Dmitrii Dolgov <[email protected]> Cc: German Gomez <[email protected]> Cc: Guilherme Amadio <[email protected]> Cc: Huacai Chen <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: James Clark <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: K Prateek Nayak <[email protected]> Cc: Kajol Jain <[email protected]> Cc: Kan Liang <[email protected]> Cc: Leo Yan <[email protected]> Cc: Li Dong <[email protected]> Cc: Liam Howlett <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Miguel Ojeda <[email protected]> Cc: Ming Wang <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Nick Terrell <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Ravi Bangoria <[email protected]> Cc: Sandipan Das <[email protected]> Cc: Sean Christopherson <[email protected]> Cc: Steinar H. Gunderson <[email protected]> Cc: Vincent Whitchurch <[email protected]> Cc: Wenyu Liu <[email protected]> Cc: Yang Jihong <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
-rw-r--r--tools/perf/util/bpf_lock_contention.c2
-rw-r--r--tools/perf/util/maps.c13
-rw-r--r--tools/perf/util/maps.h2
3 files changed, 16 insertions, 1 deletions
diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index f1716c089c99..31ff19afc20c 100644
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -318,7 +318,7 @@ int lock_contention_read(struct lock_contention *con)
}
/* make sure it loads the kernel map */
- map__load(maps__first(machine->kmaps)->map);
+ maps__load_first(machine->kmaps);
prev_key = NULL;
while (!bpf_map_get_next_key(fd, prev_key, &key)) {
diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
index 986daa1b0497..024a6c9f72c4 100644
--- a/tools/perf/util/maps.c
+++ b/tools/perf/util/maps.c
@@ -793,3 +793,16 @@ out:
}
return err;
}
+
+void maps__load_first(struct maps *maps)
+{
+ struct map_rb_node *first;
+
+ down_read(maps__lock(maps));
+
+ first = maps__first(maps);
+ if (first)
+ map__load(first->map);
+
+ up_read(maps__lock(maps));
+}
diff --git a/tools/perf/util/maps.h b/tools/perf/util/maps.h
index e4a49d6ff5cf..b7ab3ec61b7c 100644
--- a/tools/perf/util/maps.h
+++ b/tools/perf/util/maps.h
@@ -142,4 +142,6 @@ void __maps__sort_by_name(struct maps *maps);
void maps__fixup_end(struct maps *maps);
+void maps__load_first(struct maps *maps);
+
#endif // __PERF_MAPS_H