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

[Vinson Lee]

On Mon, Feb 16, 2015 at 12:50 PM, Yann Droneaud <ydroneaud@xxxxxxxxxx> wrote:
> Hi,
>
> Le vendredi 13 fÃvrier 2015 Ã 18:06 -0800, Vinson Lee a Ãcrit :
>> From: Vinson Lee <vlee@xxxxxxxxxxx>
>>
>> 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 âperf_flag_probeâ:
>> util/cloexec.c:24: error: implicit declaration of function
>> âsched_getcpuâ
>> util/cloexec.c:24: error: nested extern declaration of âsched_getcpuâ
>> make: *** [util/cloexec.o] Error 1
>>
>> Cc: stable@xxxxxxxxxxxxxxx # 3.18+
>> Signed-off-by: Vinson Lee <vlee@xxxxxxxxxxx>
>> ---
>>  tools/perf/util/cloexec.c | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
>> index 47b78b3..3738924 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;
>>
>> +#ifdef __GLIBC_PREREQ
>> +#if __GLIBC_PREREQ(2, 6)
>> +#define HAVE_SCHED_GETCPU
>> +#endif
>> +#endif
>> +
>
> OK
>
>>  static int perf_flag_probe(void)
>>  {
>>       /* use 'safest' configuration as used in perf_evsel__fallback() */
>> @@ -21,9 +27,13 @@ static int perf_flag_probe(void)
>>       pid_t pid = -1;
>>       char sbuf[STRERR_BUFSIZE];
>>
>> +#ifdef HAVE_SCHED_GETCPU
>>       cpu = sched_getcpu();
>>       if (cpu < 0)
>>               cpu = 0;
>> +#else
>> +     cpu = 0;
>> +#endif
>>
>>       while (1) {
>>               /* check cloexec flag */
>
> I've reviewed the use of __GLIBC_PREREQ(2, 6), but not whether using cpu
> = 0 is OK if sched_getcpu() is not available.
>
> Reviewed-by: Yann Droneaud <ydroneaud@xxxxxxxxxx>
>
> Regards.
>
> --
> Yann Droneaud
> OPTEYA
>
>
>

Ping. Please review the sched_getcpu hunk.
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