On Thu, 27 Apr 2023 12:31:24 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 in full gc code src/hotspot/share/gc/g1/g1CollectionSetChooser.hpp line 57: > 55: // Determine whether to add the given region to the collection set > candidates or > 56: // not. Currently, we skip regions that we will never move during young > gc, and > 57: // regions which liveness is below the occupancy threshold. s/liveness is below/liveness is over/ ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/13643#discussion_r1181174243
