RFR: 8303749: Serial: Use more strict card table API

[Thomas Schatzl]

On Tue, 7 Mar 2023 13:29:50 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Simple refactoring to skip an unnecessary guard check.
> 
> Test: tier1-3

Lgtm.

src/hotspot/share/gc/serial/cardTableRS.cpp line 160:

> 158:     clear_MemRegion(to_be_cleared_mr);
> 159:   }
> 160:   dirty_MemRegion(used_mr);

Now that `invalidate()` isn't called any more, it might be useful to rename the method to `dirty_or_clear()` or something. In general I think that "dirty" is more specific and clear than "invalidate", but the "invalidate" term probably stems from wanting to be generic (not only here).
So feel free to ignore this suggestions.

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Marked as reviewed by tschatzl (Reviewer).

PR: https://git.openjdk.org/jdk/pull/12902