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

[Calvin Cheung]

Hi Jiangli,

I've updated the webrev at the same location:
     http://cr.openjdk.java.net/~ccheung/8065050/webrev/

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
>>>
>>
>