RFR: 8260941: Remove the conc_scan parameter for CardTable

[Kim Barrett]

On Fri, 5 Feb 2021 09:52:25 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

> Hi,
> 
>   can I have reviews for this removal of the last(?) CMS-specific code in CardTable, namely some provision to indicate that cards are being scanned concurrently in Serial/Parallel GC barrier code?
> 
> The change simply follows the predicate into Serial/Parallel GC code which always returns false for them and removes that code.
> 
> In the review for JDK-8234534 I mentioned that I split this out due to unexplainable errors; testing tier1-5 three times showed none of that any more (after updating to latest code).
> 
> This change has only been built on Oracle-platforms and linux-x86 via github actions (https://github.com/tschatzl/jdk/actions/runs/539993964), so I would like to kindly ask maintainers of the others to compile and report issues (32 bit ARM, PPC etc).
> 
> Testing: tier1-5

Looks good.  Just the one minor nit about "virtual".

src/hotspot/share/gc/g1/g1BarrierSet.hpp line 56:

> 54:   ~G1BarrierSet() { }
> 55: 
> 56:   bool card_mark_must_follow_store() const {

Should be "virtual".  (Probably should be "override", but nobody's gotten around to vetting and proposing that change to the style guide.)

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Marked as reviewed by kbarrett (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/2425