RFR: 8328112: Remove CardTable::_guard_region [v2]

[Albert Mingkun Yang]

On Fri, 15 Mar 2024 13:20:37 GMT, Guoxiong Li <gli at openjdk.org> wrote:

>> Hi all,
>> 
>> This patch removes the `CardTable::_guard_region`. Thanks for taking the time to review.
>> 
>> Best Regards,
>> -- Guoxiong
>
> Guoxiong Li has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove guard card.

src/hotspot/share/gc/shared/cardTable.cpp line 82:

> 80: 
> 81:   // each card takes 1 byte; + 1 for the guard card
> 82:   size_t num_bytes = num_cards + 1;

I think it's better not to remove the `num_bytes` var. Otherwise, one have keep `one card == one byte` in mind everywhere #bytes is expected but #cards is used.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18324#discussion_r1526288722