RFR (M): 8189737: Make HeapRegion not derive from Space

Thomas Schatzl thomas.schatzl at oracle.com
Thu Oct 31 13:43:17 UTC 2019


Hi all,

   can I get reviews for this refactoring that removes the inheritance 
of HeapRegion from Space?

Since JDK10 we did not use much of the shared code in G1, so apart from 
inheriting a few trivial members (bottom, top, compaction_top) there is 
not much gain in inheriting from (Contiguous-)Space, except adding quite 
a few unused members and lots of legacy code.

In JDK10 we already considered removing this inheritance, but never got 
around until now :)

There will be a follow-up JDK-8233306 that cleans up the code a bit 
(sorting members and methods), but to keep this a bit more easily 
reviewable, the change is as it is.

The change is smaller than webrev indicates, for some reason the 
single-line include change in test_g1HeapVerifier.cpp caused it to be 
included as a "new" file. There is also a lot of one-line 
#include-wrangling.

CR:
https://bugs.openjdk.java.net/browse/JDK-8189737
Webrev:
http://cr.openjdk.java.net/~tschatzl/8189737/webrev/
Testing:
hs-tier-1-5

Thanks,
   Thomas



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