RFR (XS): 8193105: Print error code when map_memory_to_file() fails

[sangheon.kim]

On 12/06/2017 05:54 PM, David Holmes wrote:
> On 7/12/2017 5:30 AM, Sangheon Kim wrote:
>> On 2017-12-06 오전 11:19, sangheon.kim wrote:
>>> Hi David,
>>>
>>> Thank you for reviewing this.
>>>
>>> On 12/06/2017 03:31 AM, David Holmes wrote:
>>>> On 6/12/2017 9:25 PM, David Holmes wrote:
>>>>> Hi Sangheon,
>>>>>
>>>>> On 6/12/2017 5:46 PM, sangheon.kim wrote:
>>>>>> Hi all,
>>>>>>
>>>>>> Could I have some reviews for this change?
>>>>>>
>>>>>> JDK-8190308 (Implementation: JEP 316: Heap Allocation on 
>>>>>> Alternative Memory Devices) introduced a new 
>>>>>> test(TestAllocateHeapAt.java) but it is failing on Solaris-Sparc 
>>>>>> with fastdebug build. But unfortunately there's no error print 
>>>>>> when related function fails.
>>>>>>
>>>>>> This proposal is simply adding error code print for further 
>>>>>> investigation of JDK-8192871(TestAllocateHeapAt fails), not 
>>>>>> change its logic.
>>>>>>
>>>>>> CR: https://bugs.openjdk.java.net/browse/JDK-8193105
>>>>>> Webrev: http://cr.openjdk.java.net/~sangheki/8193105/webrev.0
>>>>>> Testing: hs-tier1
>>>>>
>>>>> !     vm_exit_during_initialization(err_msg("Error in mapping Java 
>>>>> heap at the given filesystem directory. error(%d)", ret));
>>>>>
>>>>> You should use strerror(ret) to print a readable error string here.
>>> Done.
>>>
>>>>
>>>> Except you can't because on OSX util_posix_fallocate doesn't 
>>>> necessarily return an error code! That's another bug in this 
>>>> particular so-called "posix" function! :(
>>> OSX version of util_posix_fallocate() uses fcntl(would return 9 
>>> kinds of errors) and ftruncate(12 errors). And both functions set 
>>> errno when those functions fail(i.e. return -1) [1]. But when we get 
>>> a return value of -1, we don't know which function is failed. If 
>>> this is your concern I would prefer to address under different CR as 
>>> I wanted to add this log for Sparc ASAP. JDK-8192871 is reported on 
>>> Sparc so far.
>> Sorry, I misunderstood what you said.
>> Now I understand that OSX version is not returning the error code. I 
>> will file a new bug for this.
>
> Right. But that also means using strerror is not appropriate ... 
> though will it actually cause a problem? Let's go with Kim's 
> suggestion and just stick with your original version that prints the 
> numeric value. The strerror can be added once the other bug is fixed.
Okay, I will push webrev.0 which is you and Kim reviewed version.

FYI, I filed JDK-8193146(OSX version of util_posix_fallocate() doesn't 
return error code) to address the problem discussed above.

Thanks,
Sangheon


>
> Thanks,
> David
>
>> Thanks,
>> Sangheon
>>
>>
>>>
>>> FYI, as there are 3 duplicated errors(EACCES, EBADF and EINVAL) 
>>> between 2 functions, we can't distinguish in these cases.
>>>
>>> webrev: http://cr.openjdk.java.net/~sangheki/8193105/webrev.1
>>>
>>> [1]:
>>> http://www.manpages.info/macosx/fcntl.2.html
>>> http://www.manpages.info/macosx/ftruncate.2.html
>>>
>>> Thanks,
>>> Sangheon
>>>
>>>
>>>>
>>>> David
>>>>
>>>>> Thanks,
>>>>> David
>>>>>
>>>>>> Thanks,
>>>>>> Sangheon
>>>
>>