RFR(xxs): 8199432: metaspace: fix wrong comment and condition in SpaceManager::verify()

Thomas Stüfe thomas.stuefe at gmail.com
Wed Mar 14 19:01:28 UTC 2018

Hi Coleen,

short question. This patch changes SpaceManager::verify in the sense that
now  SpaceManager::verify does now do something useful (iterating the
chunks of a class loader). This - over several steps - will lead to
"VerifyBefore/AfterGC" making more verifications in fastdebug.

I ran this patch through submit-hs (what I suppose is "tier1"?) and all was
well. Should I test anything else? I am a bit unsure since yesterday.

Thank you, Thomas

On Tue, Mar 13, 2018 at 11:04 PM, <coleen.phillimore at oracle.com> wrote:

> This looks good and potentially trivial.
> Coleen
> On 3/12/18 3:23 AM, Thomas Stüfe wrote:
>> Hi all,
>> may I please have sponsor/reviewers for this tiny fix:
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8199432
>> webrev: http://cr.openjdk.java.net/~stuefe/webrevs/8199432-fix-space
>> manager-
>> verify/webrev.00/webrev/
>> Basically, the condition and the comment make no sense anymore.
>> They used to make sense: in an earlier version of the Metaspace ("6964458:
>> Reimplement class meta-data storage to use native memory") the Metablocks
>> inside a metachunk always had headers and therefore were walkable. So,
>> Metachunk::verify walked all the blocks - which was not possible if were
>> returned with Metaspace::deallocate() and added to the block dictionary.
>> This is not true anymore, now MetaBlocks generally do not have a header,
>> so
>> MetaChunk::verify() does not walk them and is generally oblivious to
>> anything happening in the MetaChunk payload area. So, one can now always
>> call MetaChunk::verify(), regardless if MetaBlocks are in the block
>> dictionary or not.
>> Thanks, Thomas

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