On Tue, 2 May 2023 16:47:06 GMT, Thomas Schatzl <tscha...@openjdk.org> wrote:

>> Hi all,
>> 
>>   please review this change that removes the pinned tag from `HeapRegion`.
>> 
>> So that "pinned" tag for G1 heap regions indicates that the region should 
>> not move during (young) gc. This applies to now removed archive regions and 
>> humongous objects/regions.
>> 
>> With "real" g1 region pinning to deal with gclocker in g1 once and for all 
>> upcoming we need a refcount, a single bit is not sufficient anymore. Further 
>> there will be a naming conflict as this kind of "pinning" is different to g1 
>> region pinning "pinning". The former indicates "contents can not be moved, 
>> but can be reclaimed", while the latter means "contents can not be moved and 
>> not reclaimed".
>> 
>> The (current) pinned flag is surprisingly little used, only for policy 
>> decisions.
>> 
>> The suggestion this change implements is to remove the "pinned" tag as it 
>> is, and reserve it for future g1 region pinning (that needs to store the 
>> pinning attribute differently as a refcount anyway).
>> 
>> Testing: tier1-3, gha
>> 
>> Thanks,
>>   Thomas
>
> Thomas Schatzl has updated the pull request incrementally with one additional 
> commit since the last revision:
> 
>   Remove is_young_gc_movable

Sorry to be late to the review.  I noticed a problem in a comment.

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PR Review: https://git.openjdk.org/jdk/pull/13643#pullrequestreview-1407061087

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