[jdk8u] RFR: 8316278 G1: Clean up code in ptrQueue.[ch]pp and ptrQueue.inline.hpp

[Severin Gehwolf]

On Tue, 19 Sep 2023 02:09:15 GMT, Sun Jianye <jianyesun at openjdk.org> wrote:

> Hi~,  as reported by issue :  https://bugs.openjdk.org/browse/JDK-8316278 .  We found  the indexing method of PtrQueue's buf  is not  correct  when  converting an integer of type size_t to type int, then calling the method PtrQueue::byte_index_to_index . 
> The key problem is this way of using: 
> 
> size_t i=0;    _buf[byte_index_to_index((int)i)] = NULL;  
> 
> The return value of the function byte_index_to_index is the index of the array _buf, and it should be non-negative. So it's should be a type of size_t. 
> Currently we have found 2 issues related to this problem,  https://bugs.openjdk.org/browse/JDK-8308169 and  https://bugs.openjdk.org/browse/JDK-8303961.  They are all triggered by a special  size number of buf, like '-XX:G1UpdateBufferSize=512M'  or  '-XX:G1SATBBufferSize=500m'
> We found  [JDK-6899049](https://bugs.openjdk.org/browse/JDK-6899049) can sovle it, so please let's do backport it. We also added a test case.
> Thanks.

You also need to create the backport PR title as `Backport <sha-of-original-change>` so that the bots recognize it as backport. One way to figure this out is to go to a later JDK version, jdk11u-dev, for example and use `git log --grep 8316278`. HTH.

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PR Comment: https://git.openjdk.org/jdk8u/pull/50#issuecomment-1725153907