8236569: -Xss not multiple of 4K does not work for the main thread on macOS #4256

slowhog · 2021-05-28T21:55:24Z

…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.

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);
        }
    }
}

Progress

Change must not contain extraneous whitespace
Commit message must refer to an issue
Change must be properly reviewed

Issue

JDK-8236569: -Xss not multiple of 4K does not work for the main thread on macOS

Reviewers

David Holmes (@dholmes-ora - Reviewer)
Alan Bateman (@AlanBateman - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/4256/head:pull/4256
$ git checkout pull/4256

Update a local copy of the PR:
$ git checkout pull/4256
$ git pull https://git.openjdk.java.net/jdk pull/4256/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 4256

View PR using the GUI difftool:
$ git pr show -t 4256

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/4256.diff

…d on macOS

bridgekeeper · 2021-05-28T21:55:30Z

👋 Welcome back henryjen! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2021-05-28T22:00:50Z

@slowhog The following label will be automatically applied to this pull request:

core-libs

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

mlbridge · 2021-05-28T22:04:30Z

Webrevs

dholmes-ora · 2021-05-30T03:00:56Z

src/java.base/macosx/native/libjli/java_md_macosx.m

@@ -722,6 +723,16 @@ static void MacOSXStartup(int argc, char *argv[]) {
    return (void*)(intptr_t)JavaMain(args);
 }

+static size_t alignUp(size_t stack_size) {
+    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 ?

sysconf is the portable way based on POSIX, we can use getpagesize give this is macOS specific code, which is BSD based.

slowhog · 2021-06-03T21:58:54Z

Withdraw for keep current behavior for compatibility. It would be preferred for user to specify proper value than we change the value on user's behalf.

dholmes-ora · 2021-06-07T02:22:55Z

I'm a bit confused about the state of this PR. It was closed/withdrawn but then reopened but with changes applied to platforms other than macOS - why?

dholmes-ora · 2021-06-07T02:23:57Z

Also the code does not compile on Linux in current form.

slowhog · 2021-06-07T03:22:18Z

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.

dholmes-ora · 2021-06-07T05:10:57Z

while some other Posix system might as explained in the man page

What manpage?

The POSIX specification for this does not allow for EINVAL being returned due to alignment issues. That is an extra constraint imposed by macOS and which makes it non-conforming to the POSIX spec IMO. While the changes in src/java.base/unix/native/libjli/java_md.c seem perfectly fine, are we actually ever going to execute it?

slowhog · 2021-06-07T15:18:42Z

Linux man page for pthread_attr_setstacksize() states that,

   On some systems, pthread_attr_setstacksize() can fail with the
   error EINVAL if stacksize is not a multiple of the system page
   size.

dholmes-ora

Hi Henry,

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

The help text needs tweaking - see CSR request.

Thanks,
David

dholmes-ora · 2021-06-08T02:36:26Z

src/java.base/share/classes/sun/launcher/resources/launcher.properties

@@ -172,6 +172,8 @@ java.launcher.X.usage=\n\
 \                      (Linux Only) show host system or container\n\
 \                      configuration and continue\n\
 \    -Xss<size>        set java thread stack size\n\
+\                      The actual size may be round up to multiple of system\n\


See updated help text in the CSR request.

Updated, thanks

openjdk · 2021-06-08T02:59:41Z

@slowhog This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

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

Reviewed-by: dholmes, alanb

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 684 new commits pushed to the master branch:

f4b3ee5: 8270280: security/infra/java/security/cert/CertPathValidator/certification/LetsEncryptCA.java OCSP response error
45abbee: 8243543: jtreg test security/infra/java/security/cert/CertPathValidator/certification/BuypassCA.java fails
c9251db: 8271209: Fix doc comment typos in JavadocTokenizer
96247ae: 8270187: G1: Remove ConcGCThreads constraint
9b27df6: 8271063: Print injected fields for InstanceKlass
0cc4bb7: 8270870: Simplify G1ServiceThread
8c8e3a0: 8271163: G1 uses wrong degree of MT processing since JDK-8270169
8a789b7: 8263840: PeriodicTask should declare its destructor virtual
f226190: 8270894: Use acquire semantics in ObjectSynchronizer::read_stable_mark()
ea182b5: 8271060: Merge G1CollectedHeap::determine_start_concurrent_mark_gc and G1Policy::decide_on_conc_mark_initiation
... and 674 more: https://git.openjdk.java.net/jdk/compare/52d88ee1d1e0f6b9927db03a2b0bff75e4be03a2...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

tstuefe

Hi,

proposed shorter form. Otherwise this looks fine.

Cheers, Thomas

tstuefe · 2021-06-08T08:17:54Z

src/java.base/unix/native/libjli/java_md.c

+        }
+        return page_size * pages;
+    }
+}


Could probably be shortened to something like this:

size_t pagesize = (size_t)sysconf(_SC_PAGESIZE); return (stack_size + (pagesize - 1)) & ~(pagesize - 1);

or, if you insist on checking for SIZE_MAX:

size_t pagesize = (size_t)sysconf(_SC_PAGESIZE); size_t max = SIZE_MAX - pagesize; return stack_size <= max ? (stack_size + (pagesize - 1)) & ~(pagesize - 1) : max;

(I see David requested this, so this is fine, though passing SIZE_MAX to this function will quite likely fail anyway :)

While sysconf(_SC_PAGESIZE) is most likely(if not always) be power of 2, it's not a constant we know for sure here and this is not critical path for performance, thus I didn't take that approach.

My concern was not performance but brevity, especially since you add the same function twice. And about using the same logic for aligning up as we do within hotspot (see align.hpp). You also mix up size_t and long (signed vs unsigned, and potentially different sizes) - there is nothing obvious wrong with that but I would at least consistently use size_t here.

tstuefe · 2021-06-08T13:37:10Z

Please make sure the failing tests have nothing to do with your patch. gc/shenandoah/compiler/TestLinkToNativeRBP.java
sounds at least suggestive.

mlbridge · 2021-06-09T01:11:48Z

Mailing list message from David Holmes on core-libs-dev:

On 8/06/2021 11:40 pm, Thomas Stuefe wrote:

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
Please make sure the failing tests have nothing to do with your patch. `gc/shenandoah/compiler/TestLinkToNativeRBP.java`
sounds at least suggestive.

warning: using incubating module(s): jdk.incubator.foreign
/home/runner/work/jdk/jdk/test/hotspot/jtreg/gc/shenandoah/compiler/TestLinkToNativeRBP.java:42:
error: cannot find symbol
import jdk.incubator.foreign.LibraryLookup;

Looks like shenandoah test was not updated for latest Foreign changes.

David

mlbridge · 2021-06-09T01:11:50Z

Mailing list message from David Holmes on core-libs-dev:

On 8/06/2021 11:40 pm, Thomas Stuefe wrote:

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
Please make sure the failing tests have nothing to do with your patch. `gc/shenandoah/compiler/TestLinkToNativeRBP.java`
sounds at least suggestive.

warning: using incubating module(s): jdk.incubator.foreign
/home/runner/work/jdk/jdk/test/hotspot/jtreg/gc/shenandoah/compiler/TestLinkToNativeRBP.java:42:
error: cannot find symbol
import jdk.incubator.foreign.LibraryLookup;

Looks like shenandoah test was not updated for latest Foreign changes.

David

bridgekeeper · 2021-07-07T05:38:27Z

@slowhog This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

slowhog · 2021-07-14T23:51:52Z

Still pending CSR, also considering adapt hotspot align up as suggested by @tstuefe.

AlanBateman · 2021-07-23T15:21:11Z

src/java.base/unix/native/libjli/java_md.c


    if (stack_size > 0) {
-        pthread_attr_setstacksize(&attr, stack_size);
+        if (EINVAL == pthread_attr_setstacksize(&attr, stack_size)) {


Style-wise it might be more consistent put EINVAL on the RHS of the ==.

bridgekeeper · 2021-08-20T18:14:32Z

@slowhog This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

bridgekeeper · 2021-09-17T20:26:05Z

@slowhog This pull request has been inactive for more than 8 weeks and will now be automatically closed. If you would like to continue working on this pull request in the future, feel free to reopen it! This can be done using the /open pull request command.

asotona · 2022-05-31T07:52:03Z

/open

openjdk · 2022-05-31T07:52:49Z

@asotona Only the pull request author can set the pull request state to "open"

asotona · 2022-05-31T08:38:51Z

Continuation in #8953

JDK-8236569: -Xss not multiple of 4K does not work for the main threa…

fb9b22d

…d on macOS

openjdk bot changed the title ~~JDK-8236569: -Xss not multiple of 4K does not work for the main threa…~~ 8236569: -Xss not multiple of 4K does not work for the main thread on macOS May 28, 2021

openjdk bot added the rfr Pull request is ready for review label May 28, 2021

openjdk bot added the core-libs core-libs-dev@openjdk.org label May 28, 2021

dholmes-ora reviewed May 30, 2021

View reviewed changes

slowhog closed this Jun 3, 2021

Avoid overflow on page size

39b041d

slowhog reopened this Jun 4, 2021

slowhog added 3 commits June 4, 2021 17:12

Only try to round-up when current value failed

56d8027

Merge

1e96be9

Change java -X output for -Xss

764a1f9

slowhog added 2 commits June 7, 2021 02:56

Merge

3245696

Cast type

5a8d4a1

dholmes-ora approved these changes Jun 8, 2021

View reviewed changes

openjdk bot added the ready Pull request is ready to be integrated label Jun 8, 2021

tstuefe reviewed Jun 8, 2021

View reviewed changes

Update help text

a396661

dholmes-ora approved these changes Jun 9, 2021

View reviewed changes

AlanBateman approved these changes Jul 23, 2021

View reviewed changes

bridgekeeper bot closed this Sep 17, 2021

asotona mentioned this pull request May 31, 2022

8236569: -Xss not multiple of 4K does not work for the main thread on macOS #8953

Closed

3 tasks

slowhog deleted the JDK-8236569 branch January 16, 2025 00:41

8236569: -Xss not multiple of 4K does not work for the main thread on macOS #4256

8236569: -Xss not multiple of 4K does not work for the main thread on macOS #4256

Uh oh!

Conversation

slowhog commented May 28, 2021 • edited by openjdk bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Progress

Issue

Reviewers

Reviewing

Uh oh!

bridgekeeper bot commented May 28, 2021

Uh oh!

openjdk bot commented May 28, 2021

Uh oh!

mlbridge bot commented May 28, 2021 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Webrevs

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

slowhog commented Jun 3, 2021

Uh oh!

dholmes-ora commented Jun 7, 2021

Uh oh!

dholmes-ora commented Jun 7, 2021

Uh oh!

slowhog commented Jun 7, 2021

Uh oh!

dholmes-ora commented Jun 7, 2021

Uh oh!

slowhog commented Jun 7, 2021

Uh oh!

dholmes-ora left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

openjdk bot commented Jun 8, 2021 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

tstuefe left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

tstuefe commented Jun 8, 2021

Uh oh!

mlbridge bot commented Jun 9, 2021

Uh oh!

mlbridge bot commented Jun 9, 2021

Uh oh!

bridgekeeper bot commented Jul 7, 2021

Uh oh!

slowhog commented Jul 14, 2021

Uh oh!

Choose a reason for hiding this comment

Uh oh!

bridgekeeper bot commented Aug 20, 2021

Uh oh!

bridgekeeper bot commented Sep 17, 2021

Uh oh!

asotona commented May 31, 2022

Uh oh!

openjdk bot commented May 31, 2022

Uh oh!

asotona commented May 31, 2022

Uh oh!

Uh oh!

slowhog commented May 28, 2021 •

edited by openjdk bot

Loading

mlbridge bot commented May 28, 2021 •

edited

Loading

openjdk bot commented Jun 8, 2021 •

edited

Loading