[jdk8u-dev] RFR: 8303215: Make thread stacks not use huge pages

[Takuya Kiriyama]

Hi All,

I would like to backport the fix for bug JDK-8303215 to JDK 8. This bug addresses an issue with Transparent Huge Pages (THP) and thread stack allocation.
This fix is unclean, but almost clean backport from jdk11.

1. Backport:
The fix is almost clean from jdk11, but there is a slight difference.

- os_linux.cpp
Since JDK 8 does not include JDK-8183552, we need to add one more include statement. JDK-8183552 will likely not be backported to 8u.

- globals_linux_aarch64.hpp
In JDK 11, `CompilerThreadStackSize` is set to 2048, whereas JDK 8 originally sets it to `0`. This change to 2048 was introduced in JDK-8140520. Since JDK-8140520 is likely not directly related to this fix, I have excluded it from this fix and changed `CompilerThreadStackSize` to 2040.

2. Bug Reproduction:
The bug was successfully reproduced in Linux x86_64 with THP enabled (/sys/kernel/mm/transparent_hugepage/enabled = always).
Reproduction was confirmed using the following dummy thread program:

public class ThreadStackHugePageTest {
        public static void main(String[] args) {
                final int NUM_THREADS = 1000;
                final long SLEEP_SECONDS = 3600;
                final long SLEEP_MILISECONDS = SLEEP_SECONDS * 1000;

                List<Thread> threads = new ArrayList<>();

                for (int i = 0; i < NUM_THREADS; i++) {
                        Runnable task = () -> {
                                try {
                                        Thread.sleep(SLEEP_MILISECONDS);
                                } catch (InterruptedException e) {
                                        Thread.currentThread().interrupt();
                                }
                        };

                        Thread thread = new Thread(task);
                        threads.add(thread);

                        thread.start();
                }

                System.out.println("all threads are started");

                for (Thread thread : threads) {
                        try {
                                thread.join();
                        } catch (InterruptedException e) {
                                Thread.currentThread().interrupt();
                        }
                }
        }
}

The fix significantly reduces the number of anonymous regions with fully occupied RSS.

3. Regression Testing:
I ran the test/hotspot tests on Linux x64 as a regression test. No failures were found.

Thank you.

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

Commit messages:
 - 8303215: Make thread stacks not use huge pages

Changes: https://git.openjdk.org/jdk8u-dev/pull/746/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=746&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303215
  Stats: 29 lines in 2 files changed: 25 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/746.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/746/head:pull/746

PR: https://git.openjdk.org/jdk8u-dev/pull/746