[libvirt] [PATCH v5 06/13] conf: Introduce address caching for PCI extensions

[Yi Min Zhao]

在 2018/9/12 下午3:35, Yi Min Zhao 写道:
>>> +static void *
>>> +virZPCIAddrCopy(const void *name)
>>> +{
>>> +    unsigned int *copy;
>>> +
>>> +    if (VIR_ALLOC(copy) < 0)
>>> +        return NULL;
>>> +
>>> +    *copy = *((unsigned int *)name);
>>> +    return (void *)copy;
>>> +}
>>> +
>>> +
>>> +static void
>>> +virZPCIAddrKeyFree(void *name)
>>> +{
>>> +    VIR_FREE(name);
>>> +}
>> This makes sense and seems to work just fine; however, you are
>> allocating and releasing a bunch of small integers, which seems
>> a bit wasteful.
>>
>> vircgroup is AFAICT avoiding all that extra memory management by
>> stuffing the values straight into the pointers themselves, which
>> you should also be able to do since the biggest legal ID is a
>> 32-bit integer.
>>
>> That said, I haven't been able to get that to actually work, at
>> least with a quick attempt :( Would you mind exploring that route
>> and figuring out whether it's feasible at all?
> I'm testing this. Actually I wanted to do so like vircgroup. I 
> remembered there's
> error due to the previous code logic. I will reply to you later. 
I remebered the reason and test again. FID might be 0. It is treated as 
an error
if we save 0 in void* pointer.

-- 
Yi Min