RFR(XS): 8065050: vm crashes during CDS dump when very small SharedMiscDataSize is specified

[David Holmes]

On 4/12/2014 11:40 AM, Calvin Cheung wrote:
> Hi Jiangli,
>
> I've updated the webrev at the same location:
>      http://cr.openjdk.java.net/~ccheung/8065050/webrev/

Seems okay. Do we have a test that sets the flags to these allowed 
minimum values and dumps and then uses the archive?

Thanks,
David

> Previous version is saved at:
>      http://cr.openjdk.java.net/~ccheung/8065050/webrev.00/
>
> thanks,
> Calvin
>
> On 12/3/2014 3:53 PM, Jiangli Zhou wrote:
>> Hi Calvin,
>>
>> On 12/03/2014 03:51 PM, Calvin Cheung wrote:
>>> On 12/3/2014 2:55 PM, Jiangli Zhou wrote:
>>>> Hi Calvin,
>>>>
>>>> It's better to define 12M and 16M as enums in metaspaceShared.hpp
>>>> now they are referenced in more than one place.
>>> So global.hpp will need to include metaspaceShared.hpp.
>>>>
>>>> I also have some questions. The 12M/16M are not introduced by this
>>>> change, do you know why those values were chosen as the default RO
>>>> and RW sizes?
>>> Sorry. I don't know the reasons why those values were chosen.
>>>> Now we require both spaces have to be at lease 12M on 32-bit
>>>> machines and 16M on 64-bit machine, is it a reasonable requirement?
>>>> What's the minimum size requirement for the RO and RW spaces with
>>>> the default classlist?
>>>
>>> Below are the numbers for the RO and RW spaces with the default
>>> classlist for various platforms:
>>> =====
>>> linux
>>> =====
>>> 64-bit
>>> ro space:   8433480 [ 37.8% of total] out of  16777216 bytes [50.3%
>>> used] at 0x0000000800000000
>>> rw space:  11418608 [ 51.1% of total] out of  16777216 bytes [68.1%
>>> used] at 0x0000000801000000
>>>
>>> 32-bit
>>> ro space:   6316488 [ 48.9% of total] out of  12582912 bytes [50.2%
>>> used] at 0x80000000
>>> rw space:   5794312 [ 44.9% of total] out of  12582912 bytes [46.0%
>>> used] at 0x80c00000
>>>
>>> ========
>>> windows
>>> ========
>>> 64-bit
>>> ro space:   7888680 [ 37.7% of total] out of  16777216 bytes [47.0%
>>> used] at 0x0000000800000000
>>> rw space:  10704496 [ 51.1% of total] out of  16777216 bytes [63.8%
>>> used] at 0x0000000801000000
>>>
>>> 32-bit
>>> ro space:   6030640 [ 49.3% of total] out of  12582912 bytes [47.9%
>>> used] at 0x14690000
>>> rw space:   5440904 [ 44.5% of total] out of  12582912 bytes [43.2%
>>> used] at 0x15290000
>>>
>>> ====
>>> mac
>>> ====
>>> 64-bit
>>> ro space:   6798968 [ 37.0% of total] out of  16777216 bytes [40.5%
>>> used] at 0x0000000800000000
>>> rw space:   9446240 [ 51.4% of total] out of  16777216 bytes [56.3%
>>> used] at 0x0000000801000000
>>>
>>> ====
>>>
>>> So maybe we can define some enums as follows and leave the default
>>> values in globals.hpp alone?
>>>
>>> min_ro_size  NOT_LP64(7*M) LP64_ONLY(9*M)
>>> min_rw_size  NOT_LP64(6*M) LP64_ONLY(12*M)
>>
>> Sounds good to me.
>>
>> Thanks,
>> Jiangli
>>
>>>
>>> thanks,
>>> Calvin
>>>
>>>>
>>>> Thanks,
>>>> Jiangli
>>>>
>>>> On 12/01/2014 12:10 PM, Calvin Cheung wrote:
>>>>> JBS: https://bugs.openjdk.java.net/browse/JDK-8065050
>>>>>
>>>>> Adding more checks on the SharedMiscDataSize, ShareReadOnlySize,
>>>>> and SharedReadWriteSize.
>>>>>
>>>>> For the SharedMiscDataSize, it is based on
>>>>> MetaspaceShared::generate_vtable_methods(). Similar to what was
>>>>> done for the SharedMiscCodeSize.
>>>>>
>>>>> For the ShareReadOnlySize and SharedReadWriteSize, I'm checking if
>>>>> they are at least the default size.
>>>>> I think it's reasonable to enforce the ro and rw sizes to be at
>>>>> least the default size. A default dump of CDS archive requires >8M
>>>>> of ro space and >11M of rw space.
>>>>>
>>>>> webrev:
>>>>>     http://cr.openjdk.java.net/~ccheung/8065050/webrev/
>>>>>
>>>>> tests:
>>>>>     ran the testcase via jtreg on linux_x64 and windows_x64
>>>>>     JPRT
>>>>>
>>>>> thanks,
>>>>> Calvin
>>>>
>>>
>>
>