lkml.org 
[lkml]   [2022]   [Aug]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 2/2] KVM: selftests: Use getcpu() instead of sched_getcpu() in rseq_test
From
Date
On 8/10/22 6:53 AM, Sean Christopherson wrote:
> On Tue, Aug 09, 2022, Gavin Shan wrote:
>> On 8/9/22 5:17 PM, Florian Weimer wrote:
>>> * Florian Weimer:
>>>
>>>> * Gavin Shan:
>>>>
>>>>> sched_getcpu() is glibc dependent and it can simply return the CPU
>>>>> ID from the registered rseq information, as Florian Weimer pointed.
>>>>> In this case, it's pointless to compare the return value from
>>>>> sched_getcpu() and that fetched from the registered rseq information.
>>>>>
>>>>> Fix the issue by replacing sched_getcpu() with getcpu(), as Florian
>>>>> suggested. The comments are modified accordingly.
>>>>
>>>> Note that getcpu was added in glibc 2.29, so perhaps you need to perform
>>>> a direct system call?
>>>
>>> One more thing: syscall(__NR_getcpu) also has the advantage that it
>>> wouldn't have to be changed again if node IDs become available via rseq
>>> and getcpu is implemented using that.
>>>
>>> Thanks,
>>> Florian
>>>
>>
>> Thanks, Florian. It makes sense to me to use syscall(__NR_getcpu) in
>> next revision. Thanks for your quick review :)
>
> +1, and definitely add a comment to prevent future "cleanup".
>

Yep, I will have something like below in next revision:

/*
* We have to perform direct system call for getcpu() because it's not
* available until glic 2.29.
*/

Thanks,
Gavin

\
 
 \ /
  Last update: 2022-08-10 02:47    [W:0.268 / U:1.156 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site