On Wed, 9 Apr 2025 14:32:43 GMT, Thomas Schatzl <tscha...@openjdk.org> wrote:
>> src/hotspot/share/gc/g1/g1ConcurrentRefineSweepTask.cpp line 83: >> >>> 81: break; >>> 82: } >>> 83: case G1RemSet::HasRefToOld : break; // Nothing special to do. >> >> Why doesn't call `inc_cards_clean_again` in this case? The card is cleared >> also. (In fact, I don't get why this needs to a separate case from >> `NoInteresting`.) > > "NoInteresting" means that the card contains no interesting reference at all. > "HasRefToOld" means that there has been an interesting reference in the card. > > The distinction between these groups of cards seems interesting to me. E.g. > out of X non-clean cards, there were A with a reference to the collection > set, B that were already marked as containing a card to the collection, C not > having any interesting card any more (transitioned from clean -> dirty -> > clean, and cleared by the mutator), D being non-parsable, and E having > references to old (and no other references). > > I could add a separate counter for these type of cards too - they can be > inferred from the total number of scanned minus the others though. I see; "clean again" means the existing interesting pointer was overwritten by mutator. I misinterpret the comment as cards transitioned from dirty to clean. ` size_t _cards_clean_again; // Dirtied cards that were cleaned.` To prevent misunderstanding, what do you think of renaming "NoInteresting" to "NoCrossRegion" and "_cards_clean_again" to "_cards_no_cross_region", or sth alike so that the 1:1 mapping is clearer? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/23739#discussion_r2036885633
