2021-08-09 04:36:14

by Davidlohr Bueso

Subject: [PATCH 6/7] perf/bench-futex, requeue: Robustify futex_wait() handling

Do not assume success and account for EAGAIN or any other return value,
however unlikely.

Signed-off-by: Davidlohr Bueso <[email protected]>
---
tools/perf/bench/futex-requeue.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c
index 80f40ee92b53..e4892ba6864f 100644
--- a/tools/perf/bench/futex-requeue.c
+++ b/tools/perf/bench/futex-requeue.c
@@ -76,6 +76,8 @@ static void print_summary(void)

static void *workerfn(void *arg __maybe_unused)
{
+ int ret;
+
pthread_mutex_lock(&thread_lock);
threads_starting--;
if (!threads_starting)
@@ -83,7 +85,18 @@ static void *workerfn(void *arg __maybe_unused)
pthread_cond_wait(&thread_worker, &thread_lock);
pthread_mutex_unlock(&thread_lock);

- futex_wait(&futex1, 0, NULL, futex_flag);
+ while (1) {
+ ret = futex_wait(&futex1, 0, NULL, futex_flag);
+ if (!ret)
+ break;
+
+ if (ret && errno != EAGAIN) {
+ if (!params.silent)
+ warn("futex_wait");
+ break;
+ }
+ }
+
return NULL;
}

--
2.26.2

2021-08-09 14:59:32

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH 6/7] perf/bench-futex, requeue: Robustify futex_wait() handling

Em Sun, Aug 08, 2021 at 09:33:00PM -0700, Davidlohr Bueso escreveu:
> Do not assume success and account for EAGAIN or any other return value,
> however unlikely.

Thanks, applied.

- Arnaldo


> Signed-off-by: Davidlohr Bueso <[email protected]>
> ---
> tools/perf/bench/futex-requeue.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c
> index 80f40ee92b53..e4892ba6864f 100644
> --- a/tools/perf/bench/futex-requeue.c
> +++ b/tools/perf/bench/futex-requeue.c
> @@ -76,6 +76,8 @@ static void print_summary(void)
>
> static void *workerfn(void *arg __maybe_unused)
> {
> + int ret;
> +
> pthread_mutex_lock(&thread_lock);
> threads_starting--;
> if (!threads_starting)
> @@ -83,7 +85,18 @@ static void *workerfn(void *arg __maybe_unused)
> pthread_cond_wait(&thread_worker, &thread_lock);
> pthread_mutex_unlock(&thread_lock);
>
> - futex_wait(&futex1, 0, NULL, futex_flag);
> + while (1) {
> + ret = futex_wait(&futex1, 0, NULL, futex_flag);
> + if (!ret)
> + break;
> +
> + if (ret && errno != EAGAIN) {
> + if (!params.silent)
> + warn("futex_wait");
> + break;
> + }
> + }
> +
> return NULL;
> }
>
> --
> 2.26.2
>

--

- Arnaldo