Request for review: 8005895: Inefficient InstanceKlass field packing wasts memory

Jiangli Zhou jiangli.zhou at
Thu Jan 10 09:57:51 PST 2013


Please review the following trivial change for repacking the 
InstanceKlass fields to improve memory efficiency.

The 'bool' typed variables, '_is_marked_dependent' and 
'_has_default_methods' were grouped with u2 typed fields. For both, 
there were 1-byte padding added on 32bit machine. We can pack those two 
boolean variables together to avoid the padding, then move one of the u2 
field to be together with '_init_state' and '_reference_type'. That 
saves 4 bytes without any real code change.



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