8334371: [AIX] Beginning with AIX 7.3 TL1 mmap() supports 64K memory pages #1362

JoKern65 · 2025-01-27T12:13:46Z

Beginning with AIX 7.3 TL1 mmap() supports 64K memory pages. As an enhancement, during the initialization of the VM the availability of this new feature is examined. If the 64K pages are supported the VM will use mmap() with 64K pages instead of shmget()/shmat() with 64K pages due to the bad 256M alignment of shmget()/shmat().

In this downport to jdk21 we want to support the new AIX 7.3 TL1 feature, but with some differences explained here:

static void query_multipage_support() in src/hotspot/os/aix/os_aix.cpp
The structure of the function was changed identically in head and jdk21. Because jdk21 beforehand used trcVerbose(...) and head beforehand used log_warning(pagesize)(...) this seems to be a difference, but I just kept the tracing functions as the were before.
src/hotspot/share/memory/virtualspace.cpp
Adding the use of os::Aix::supports_64K_mmap_pages() introduces the dependency to the header src/hotspot/os/aix/os_aix.hpp. In head this header was included with #include "runtime/os.inline.hpp" beforehand by dependant code added after jdk21. Therefore I have to include #include "runtime/os.inline.hpp" explicitely in virtualspace.cpp. #include "runtime/os.hpp" can be dropped instead.
src/hotspot/share/runtime/os.cpp
Function char* os::attempt_reserve_memory_between() does not exist in jdk21, so I do not have to port the adoptions of head there.
TEST_VM(os, aix_reserve_at_non_shmlba_aligned_address) moved from test/hotspot/gtest/runtime/test_os.cpp to test/hotspot/gtest/runtime/test_os_aix.cpp
This test function does not exist in jdk21, so there is nothing to move.

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JDK-8334371 needs maintainer approval

Issue

JDK-8334371: [AIX] Beginning with AIX 7.3 TL1 mmap() supports 64K memory pages (Enhancement - P4 - Approved)

Reviewers

Martin Doerr (@TheRealMDoerr - Reviewer)
Thomas Stuefe (@tstuefe - Reviewer) Review applies to 7a128fe2

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$ git fetch https://git.openjdk.org/jdk21u-dev.git pull/1362/head:pull/1362
$ git checkout pull/1362

Update a local copy of the PR:
$ git checkout pull/1362
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/1362/head

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https://git.openjdk.org/jdk21u-dev/pull/1362.diff

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bridgekeeper · 2025-01-27T12:14:41Z

👋 Welcome back jkern! 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 · 2025-01-27T12:14:55Z

@JoKern65 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:

8334371: [AIX] Beginning with AIX 7.3 TL1 mmap() supports 64K memory pages

Reviewed-by: mdoerr, stuefe
Backport-of: ced99066354fc6a32c587b9e3c35b07e26d3452e

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 22 new commits pushed to the master branch:

981ec16: 8347911: Limit the length of inflated text chunks
caa7cc2: 8338571: [TestBug] DefaultCloseOperation.java test not working as expected wrt instruction after JDK-8325851 fix
80253a3: 8343491: javax/management/remote/mandatory/connection/DeadLockTest.java failing with NoSuchObjectException: no such object in table
d0fbffd: 8226938: [TEST_BUG]GTK L&F: There is no Details button in FileChooser Dialog
9a2988c: 8340078: Open source several 2D tests
12070ca: 8332917: failure_handler should execute gdb "info threads" command on linux
42f0ebc: 8330647: Two CDS tests fail with -UseCompressedOops and UseSerialGC/UseParallelGC
7b7aa75: 8329692: Add more details to FrameStateTest.java test instructions
ba27543: 8325042: Remove unused JVMDITools test files
69e8c20: 8320691: Timeout handler on Windows takes 2 hours to complete
... and 12 more: https://git.openjdk.org/jdk21u-dev/compare/91e7582724f78ac924ed8003a2c80e6dc731517f...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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@TheRealMDoerr, @tstuefe) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

openjdk · 2025-01-27T12:15:19Z

This backport pull request has now been updated with issue from the original commit.

mlbridge · 2025-01-27T12:18:31Z

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TheRealMDoerr

This change differs significantly from the original change. Please explain all differences.

TheRealMDoerr

LGTM.

TheRealMDoerr · 2025-02-03T19:10:38Z

src/hotspot/share/memory/virtualspace.cpp

 #include "runtime/globals_extension.hpp"
 #include "runtime/java.hpp"
 #include "runtime/os.hpp"
+#include "runtime/os.inline.hpp"


Note that including os.hpp is no longer needed when you include os.inline.hpp.

openjdk · 2025-02-03T19:11:52Z

⚠️ @JoKern65 This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

tstuefe

Patch looks good. Thanks for doing this.

After 20 years we can finally start reducing the crud around 64k page handling. If 64K page handling is ubiquitous, you will be able to throw out the System V shm allocation path, and all that vmem_xxx stuff we wrote 20 years ago.

JoKern65 · 2025-02-04T13:22:14Z

/approval JDK-8334371 request backport to support new OS Release AIX 7.3. All needed changes compared to head described in description of this PR.

openjdk · 2025-02-04T13:22:58Z

@JoKern65
JDK-8334371: The approval request has been created successfully.

JoKern65 · 2025-02-05T09:32:26Z

/integrate

openjdk · 2025-02-05T09:33:00Z

@JoKern65
Your change (at version 8b5a6d2) is now ready to be sponsored by a Committer.

TheRealMDoerr · 2025-02-05T09:49:14Z

/sponsor

openjdk · 2025-02-05T09:50:20Z

Going to push as commit 29a5de0.
Since your change was applied there have been 22 commits pushed to the master branch:

981ec16: 8347911: Limit the length of inflated text chunks
caa7cc2: 8338571: [TestBug] DefaultCloseOperation.java test not working as expected wrt instruction after JDK-8325851 fix
80253a3: 8343491: javax/management/remote/mandatory/connection/DeadLockTest.java failing with NoSuchObjectException: no such object in table
d0fbffd: 8226938: [TEST_BUG]GTK L&F: There is no Details button in FileChooser Dialog
9a2988c: 8340078: Open source several 2D tests
12070ca: 8332917: failure_handler should execute gdb "info threads" command on linux
42f0ebc: 8330647: Two CDS tests fail with -UseCompressedOops and UseSerialGC/UseParallelGC
7b7aa75: 8329692: Add more details to FrameStateTest.java test instructions
ba27543: 8325042: Remove unused JVMDITools test files
69e8c20: 8320691: Timeout handler on Windows takes 2 hours to complete
... and 12 more: https://git.openjdk.org/jdk21u-dev/compare/91e7582724f78ac924ed8003a2c80e6dc731517f...master

Your commit was automatically rebased without conflicts.

openjdk · 2025-02-05T09:50:27Z

@TheRealMDoerr @JoKern65 Pushed as commit 29a5de0.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

Backport ced99066354fc6a32c587b9e3c35b07e26d3452e

4f85d01

openjdk bot changed the title ~~Backport ced99066354fc6a32c587b9e3c35b07e26d3452e~~ 8334371: [AIX] Beginning with AIX 7.3 TL1 mmap() supports 64K memory pages Jan 27, 2025

openjdk bot added backport Port of a pull request already in a different code base rfr Pull request is ready for review labels Jan 27, 2025

TheRealMDoerr reviewed Jan 27, 2025

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JoKern65 added 3 commits January 27, 2025 16:17

add all the changes from the original review processs

d171cf9

add more changes from the original review process

0099e3a

additionally headers

7a128fe

TheRealMDoerr approved these changes Feb 3, 2025

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tstuefe approved these changes Feb 4, 2025

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runtime/os.hpp replaced by runtime/os.inline.hpp

8b5a6d2

TheRealMDoerr approved these changes Feb 4, 2025

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openjdk bot added approval Requires approval; will be removed when approval is received ready Pull request is ready to be integrated and removed approval Requires approval; will be removed when approval is received labels Feb 4, 2025

openjdk bot added the sponsor Pull request is ready to be sponsored label Feb 5, 2025

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openjdk bot closed this Feb 5, 2025

openjdk bot removed the ready Pull request is ready to be integrated label Feb 5, 2025

openjdk bot removed rfr Pull request is ready for review sponsor Pull request is ready to be sponsored labels Feb 5, 2025

8334371: [AIX] Beginning with AIX 7.3 TL1 mmap() supports 64K memory pages #1362

8334371: [AIX] Beginning with AIX 7.3 TL1 mmap() supports 64K memory pages #1362

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