On Sun, 30 May 2021 03:00:56 GMT, David Holmes <dhol...@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);
>> }
>> }
>> }
>
> src/java.base/macosx/native/libjli/java_md_macosx.m line 727:
>
>> 725:
>> 726: static size_t alignUp(size_t stack_size) {
>> 727: long page_size = sysconf(_SC_PAGESIZE);
>
> In hotspot we use `getpagesize()`. There is also a guard for a very large
> stack (within a page of SIZE_MAX) so that rounding up does not produce zero.
sounds like that (getpagesize) should work with m1 mac as well, as they have
16k pages. will it ?
-------------
PR: https://git.openjdk.java.net/jdk/pull/4256
