From 9a4426120dddab113782ea9cb331e5c03e2231ff Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Thu, 5 Dec 2024 20:23:05 -0800 Subject: [PATCH] perf hwmon_pmu: Use openat rather than dup to refresh directory The hwmon PMU test will make a temp directory, open the directory with O_DIRECTORY then fill it with contents. As the open is before the filling the contents the later fdopendir may reflect the initial empty state, meaning no events are seen. Change to re-open the directory, rather than dup the fd, so the latest contents are seen. Minor tweaks/additions to debug messages. Signed-off-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20241206042306.1055913-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/hwmon_pmu.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/hwmon_pmu.c b/tools/perf/util/hwmon_pmu.c index e61429b38ba7b..4acb9bb19b846 100644 --- a/tools/perf/util/hwmon_pmu.c +++ b/tools/perf/util/hwmon_pmu.c @@ -258,8 +258,12 @@ static int hwmon_pmu__read_events(struct hwmon_pmu *pmu) if (pmu->pmu.sysfs_aliases_loaded) return 0; - /* Use a dup-ed fd as closedir will close it. */ - dup_fd = dup(pmu->hwmon_dir_fd); + /* + * Use a dup-ed fd as closedir will close it. Use openat so that the + * directory contents are refreshed. + */ + dup_fd = openat(pmu->hwmon_dir_fd, ".", O_DIRECTORY); + if (dup_fd == -1) return -ENOMEM; @@ -336,6 +340,9 @@ static int hwmon_pmu__read_events(struct hwmon_pmu *pmu) close(fd); } } + if (hashmap__size(&pmu->events) == 0) + pr_debug2("hwmon_pmu: %s has no events\n", pmu->pmu.name); + hashmap__for_each_entry_safe((&pmu->events), cur, tmp, bkt) { union hwmon_pmu_event_key key = { .type_and_num = cur->key, @@ -343,8 +350,8 @@ static int hwmon_pmu__read_events(struct hwmon_pmu *pmu) struct hwmon_pmu_event_value *value = cur->pvalue; if (!test_bit(HWMON_ITEM_INPUT, value->items)) { - pr_debug("hwmon_pmu: removing event '%s%d' that has no input file\n", - hwmon_type_strs[key.type], key.num); + pr_debug("hwmon_pmu: %s removing event '%s%d' that has no input file\n", + pmu->pmu.name, hwmon_type_strs[key.type], key.num); hashmap__delete(&pmu->events, key.type_and_num, &key, &value); zfree(&value->label); zfree(&value->name); -- 2.50.1