RFR (XS) : 8141641: Runtime: implement range for ErrorLogTimeout

[gerard ziemski]

On 11/16/2015 03:45 PM, David Holmes wrote:
>>> I'm making a bit of a hash of this review - sorry.
>>>
>>> I agree with Dmitry that the os::sleep call should be changed as above:
>>>
>>> os::sleep(this, ErrorLogTimeout * CONST64(1000), false);
>>>
>>> but as the sleep arg is a jlong we need to limit ErrorLogTimeout to
>>> (MAX_JLONG/1000) _but_ that's too big for uintx on
>>> 32-bit. Which means the true range is different on 32-bit versus
>>> 64-bit. So if I finally get this right we should have
>>> the range as:
>>>
>>> range(0, LP64_ONLY(MAX_JLONG/1000) NOT_LP64(UINTX_MAX))
>>>
>>> Not sure we have MAX_JLONG defined as a constant. I don't agree with
>>> just selecting the 32-bit range as that again
>>> becomes an arbitrary constraint on 64-bit.
>>
>> Since os:sleep() takes jlong (8 bytes long on both 32 and 64 bit), them
>> it would appear that the most straightforward solution is to change
>> ErrorLogTimeout type from "uintx" to "uint64_t" (also 8 bytes on both 32
>> and 64 bit) and then we can have the range simply defined as:
>>
>> range(0, max_jlong/1000)
>>
>> And then we can have:
>>
>> os::sleep(this, ErrorLogTimeout * CONST64(1000), false); // in seconds
>>
>> Do we agree?
>
> Not quite. First if ErrorLogTimeout is 64-bit then we don't need to apply CONST64 to 1000 as integer promotion will take
> care of it. But we then pass an unsigned 64-bit value where a signed 64-bit value is expected and that will need a cast
> to avoid a conversion warning.
>
> So perhaps ErrorLogTimeout should be int64_t instead - even though only positive values are valid?

There is no int64_t allowed in the globals's macro definition - uint64_t seems like the best type we have available here 
for jlong.

So perhaps:

os::sleep(this, (jlong)ErrorLogTimeout * 1000, false); // in seconds

is the closest/best we can do?


cheers