Re: [PATCH 2/5] glibc: sched_getcpu(): use rseq cpu_id TLS on Linux (v2)

[Mathieu Desnoyers <mathieu.desnoyers@efficios.com>]

----- On Apr 18, 2019, at 11:33 AM, Szabolcs Nagy Szabolcs.Nagy@arm.com wrote:

> On 16/04/2019 18:32, Mathieu Desnoyers wrote:
>> --- a/sysdeps/unix/sysv/linux/sched_getcpu.c
>> +++ b/sysdeps/unix/sysv/linux/sched_getcpu.c
>> @@ -37,3 +37,26 @@ sched_getcpu (void)
>>    return -1;
>>  #endif
>>  }
>> +
>> +#ifdef __NR_rseq
>> +#include <sys/rseq.h>
>> +#endif
>> +
>> +#if defined __NR_rseq && defined RSEQ_SIG
>> +extern __attribute__ ((tls_model ("initial-exec")))
>> +__thread volatile struct rseq __rseq_abi;
> 
> i'd expect sys/rseq.h to provide this declaration.

And it actually does! Will remove this duplicate.

Thanks,

Mathieu

> 
>> +
>> +int
>> +sched_getcpu (void)
>> +{
>> +  int cpu_id = __rseq_abi.cpu_id;
>> +
>> +  return cpu_id >= 0 ? cpu_id : vsyscall_sched_getcpu ();
>> +}
>> +#else
>> +int
>> +sched_getcpu (void)
>> +{
>> +  return vsyscall_sched_getcpu ();
>> +}
>> +#endif
>> -- 2.17.1

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com