On Mon, 7 Jun 2021 03:18:32 GMT, Henry Jen <[email protected]> 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
Planned to close JDK-8236569 as 'Won't Fix', as the issue was re-opened, we
give it another shot. As explained in the CSR review, we will only round-up the
stack size as required by the operating system. Test on Ubuntu shows that there
is no need to round-up, while some other Posix system might as explained in the
man page.
We round-up for MacOS as the document explicitly said that the size need to be
multiple of system page size. I also changed to use getpagesize() as you
suggested, although that's not needed.
-------------
PR: https://git.openjdk.java.net/jdk/pull/4256
