Re: [Xen-devel] [PATCH] xen: superficial clean-ups

[chenbaodong <chenbaodong@mxnavi.com>]

On 6/11/19 18:29, Juergen Gross wrote:
> On 11.06.19 12:27, Andrew Cooper wrote:
>> On 11/06/2019 11:25, Juergen Gross wrote:
>>> On 11.06.19 12:18, George Dunlap wrote:
>>>> On 6/11/19 10:20 AM, Baodong Chen wrote:
>>>>> * Remove redundant set 'DOMDYING_dead'
>>>>> domain_create() will set this when fail, thus no need
>>>>> set in arch_domain_create().
>>>>>
>>>>> * Set error when really happened
>>>>
>>>>> diff --git a/xen/common/schedule.c b/xen/common/schedule.c
>>>>> index 86341bc..d6cdcf8 100644
>>>>> --- a/xen/common/schedule.c
>>>>> +++ b/xen/common/schedule.c
>>>>> @@ -1894,9 +1894,11 @@ struct scheduler *scheduler_alloc(unsigned
>>>>> int sched_id, int *perr)
>>>>>        return NULL;
>>>>>       found:
>>>>> -    *perr = -ENOMEM;
>>>>>        if ( (sched = xmalloc(struct scheduler)) == NULL )
>>>>> +    {
>>>>> +        *perr = -ENOMEM;
>>>>>            return NULL;
>>>>> +    }
>>>>>        memcpy(sched, schedulers[i], sizeof(*sched));
>>>>>        if ( (*perr = SCHED_OP(sched, init)) != 0 )
>>>>
>>>> I was going to say, this is a common idiom in the Xen code, and the
>>>> compiler will end up re-organizing things such that the write doesn't
>>>> happen anyway.  But in this case, its' actually writing through a
>>>> pointer before and after a function call; I don't think the compiler
>>>> would actually be allowed to optimize this write away.
>>>>
>>>> So, I guess I'd be OK with this particular hunk.  Dario, any opinions?
>>>
>>> I'd rather switch to PTR_ERR() here dropping the perr parameter.
>>
>> +2 for this, but I was going to wait until core scheduling had gotten a
>> bit further before suggesting cleanup which is guaranteed to collide.
>>
>> Sadly, it's fairly intrusive in the cpupool code as well.
>
> I can add this to my list of scheduler cleanups to do.
Copy that.
>
>
> Juergen
> .
>

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