Re: [PATCH v3] perf tools: Work around lack of sched_getcpu in glibc < 2.6.

Namhyung Kim
2015-03-24T00:28:44Z

Hi Vinson,

On Mon, Mar 23, 2015 at 12:09:16PM -0700, Vinson Lee wrote:
> From: Vinson Lee <vlee@twitter.com>
>
> This patch fixes this build error with glibc < 2.6.
>
> CC util/cloexec.o
> cc1: warnings being treated as errors
> util/cloexec.c: In function ‘perf_flag_probe’:
> util/cloexec.c:24: error: implicit declaration of function
> ‘sched_getcpu’
> util/cloexec.c:24: error: nested extern declaration of ‘sched_getcpu’
> make: *** [util/cloexec.o] Error 1
>
> Cc: stable@vger.kernel.org # 3.18+
> Signed-off-by: Vinson Lee <vlee@twitter.com>

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung

> ---
> tools/perf/util/cloexec.c | 6 ++++++
> tools/perf/util/cloexec.h | 6 ++++++
> 2 files changed, 12 insertions(+)
>
> diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
> index 6da965b..85b5238 100644
> --- a/tools/perf/util/cloexec.c
> +++ b/tools/perf/util/cloexec.c
> @@ -7,6 +7,12 @@
>
> static unsigned long flag = PERF_FLAG_FD_CLOEXEC;
>
> +int __weak sched_getcpu(void)
> +{
> + errno = ENOSYS;
> + return -1;
> +}
> +
> static int perf_flag_probe(void)
> {
> /* use 'safest' configuration as used in perf_evsel__fallback() */
> diff --git a/tools/perf/util/cloexec.h b/tools/perf/util/cloexec.h
> index 94a5a7d..68888c2 100644
> --- a/tools/perf/util/cloexec.h
> +++ b/tools/perf/util/cloexec.h
> @@ -3,4 +3,10 @@
>
> unsigned long perf_event_open_cloexec_flag(void);
>
> +#ifdef __GLIBC_PREREQ
> +#if !__GLIBC_PREREQ(2, 6)
> +extern int sched_getcpu(void) __THROW;
> +#endif
> +#endif
> +
> #endif /* __PERF_CLOEXEC_H */
> --
> 1.8.2.1
>
> --
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