RFR: 8236569: -Xss not multiple of 4K does not work for the main thread on macOS [v5]

[David Holmes]

On Mon, 7 Jun 2021 03:18:32 GMT, Henry Jen <henryjen at openjdk.org> wrote:

>> …d on macOS
>> 
>> This patch simply round up the specified stack size to multiple of the system page size. 
>> 
>> Test is trivial, simply run java with -Xss option against following code. On MacOS, before the fix, running with `-Xss159k` and `-Xss160k` would get `7183` and `649` respectively. After fix, both would output `649`, while `-Xss161k` would be same as `-Xss164k` and see 691 as the output.
>> 
>> ```code:java
>> public class StackLeak {
>>     public int depth = 0;
>>     public void stackLeak() {
>>         depth++;
>>         stackLeak();
>>     }
>> 
>>     public static void main(String[] args) {
>>         var test = new StackLeak();
>>         try {
>>             test.stackLeak();
>>         } catch (Throwable e) {
>>             System.out.println(test.depth);
>>         }
>>     }
>> }
>
> Henry Jen has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains seven additional commits since the last revision:
> 
>  - Cast type
>  - Merge
>  - Change java -X output for -Xss
>  - Merge
>  - Only try to round-up when current value failed
>  - Avoid overflow on page size
>  - JDK-8236569: -Xss not multiple of 4K does not work for the main thread on macOS

Hi Henry,

I'm okay with these changes in the current form.

The help text needs tweaking - see CSR request.

Thanks,
David

src/java.base/share/classes/sun/launcher/resources/launcher.properties line 175:

> 173: \                      configuration and continue\n\
> 174: \    -Xss<size>        set java thread stack size\n\
> 175: \                      The actual size may be round up to multiple of system\n\

See updated help text in the CSR request.

-------------

Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4256