RFR: 8280374: G1: Remove unnecessary prev bitmap mark

[Thomas Schatzl]

On Thu, 20 Jan 2022 09:49:37 GMT, Hamlin Li <mli at openjdk.org> wrote:

> In JDK-8278917, the prev bitmap is used to mark evac failure objs, so at the post of evacuation, the evacuation failure objects are already marked during pss evacuation, so there is no need to mark them again in remove self forwardee phase.

Lgtm apart from the comment. I'll push this through our internal test suite and report back any issues.

src/hotspot/share/gc/g1/g1EvacFailure.cpp line 136:

> 134:       }
> 135:     }
> 136:     _cm->clear_range_in_prev_bitmap(mr);

The comment in line 107 needs to be updated to something like:


// Fill the memory area from start to end with filler objects, and update the BOT
// accordingly. Since we clear and use the prev bitmap for marking objects that
// failed evacuation, there is no work to be done there.

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Marked as reviewed by tschatzl (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/7153