8373295: Wrong log tag for UseCompressedOops ergo setting

[iklam]

Please review this trivial change: Ergonomic settings of UseCompressedOops should be logged with log_debug(gc, heap, coops)

Note: this is the same log channel used just a few lines above.

jdk/src/hotspot/share/runtime/arguments.cpp

Lines 1579 to 1586 in c9ab330

	if (HeapBaseMinAddress < DefaultHeapBaseMinAddress) {
	// matches compressed oops printing flags
	log_debug(gc, heap, coops)("HeapBaseMinAddress must be at least %zu "
	"(%zuG) which is greater than value given %zu",
	DefaultHeapBaseMinAddress,
	DefaultHeapBaseMinAddress/G,
	HeapBaseMinAddress);
	FLAG_SET_ERGO(HeapBaseMinAddress, DefaultHeapBaseMinAddress);

---

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Issue

• JDK-8373295: Wrong log tag for UseCompressedOops ergo setting (Bug - P4)

Reviewers

• David Holmes (@dholmes-ora - Reviewer)
• Yasumasa Suenaga (@YaSuenag - Reviewer)

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[openjdk]

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

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

8373295: Wrong log tag for UseCompressedOops ergo setting

Reviewed-by: dholmes, ysuenaga

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At the time when this comment was updated there had been 10 new commits pushed to the master branch:

• 020e3f9: 8373293: Change the exception handling in TestNestHostErrorWithMultiThread.java
• 35fe0b1: 8372641: [s390x] Test failure TestMergeStores.java
• c9ab330: 8373116: Genshen: arraycopy_work should be always done for arrays in old gen during young concurrent marking
• ... and 7 more: https://git.openjdk.org/jdk/compare/811591c5c332e6427dc96819451e046841fe635b...master

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[mlbridge]

Webrevs

• 01: Full - Incremental (8910b775)
• 00: Full (bae01e13)

[YaSuenag]

I completely agree with your change!

But I received review that it should not be changed from CDS tag (I know it is aot now). See review thread in my past proposal for details: https://mail.openjdk.org/pipermail/hotspot-runtime-dev/2019-October/036315.html

I'm happy to approve if we can accept.

[dholmes-ora]

The CDS logging line was put in for JDK-8226462, and as referenced by Yasumasa it was there for CDS users to be informed (or perhaps more accurately for one of our CDS tests to check it). Does that test no longer exist, or check this condition?

[iklam]

The CDS logging line was put in for JDK-8226462, and as referenced by Yasumasa it was there for CDS users to be informed (or perhaps more accurately for one of our CDS tests to check it). Does that test no longer exist, or check this condition?

This log is used only by the SysDictCras.java test .

CDS dumping requires UseCompressedClassPointers==true. In the time of JDK-8226462, when running on a host with lot of RAM, UseCompressedOops would be disabled, which causes UseCompressedClassPointers to be disabled, which caused the CDS dump to fail.

This is no longer the case -- UseCompressedClassPointers is now independent of UseCompressedOops

$ java -XX:MaxRAM=512g -XX:MaxRAMPercentage=12.5 -XX:+PrintFlagsFinal --version | grep UseCompressedClassPointers
     bool UseCompressedClassPointers   = true   {product} {default}

Also, the test is kind of pointless now. The only significant VM flags are

• -XX:SharedBaseAddress=0: this is covered by other test cases such as test/hotspot/jtreg/runtime/cds/appcds/ArchiveRelocationTest.java
• -XX:MaxRAMPercentage=12.5: this might have been useful in reproducing the original crash but it's no longer relevant.

So I removed this test altogether.

[dholmes-ora]

If test is no longer relevant then change seems fine.

[YaSuenag]

Thank you for fixing this!

[iklam]

Thanks @YaSuenag @dholmes-ora for the review
/integrate

[openjdk]

Going to push as commit 8c8d21d.
Since your change was applied there have been 19 commits pushed to the master branch:

• a4eb57c: 8367028: compiler/c2/irTests/TestFloat16ScalarOperations.java failing intermittently because of constant folding
• 830c4d3: 8366272: The os::xxx APIs do not manage errno correctly
• 0a55789: 8373025: test/hotspot/jtreg/gc/cslocker/TestCSLocker.java may deadlock
• ... and 16 more: https://git.openjdk.org/jdk/compare/811591c5c332e6427dc96819451e046841fe635b...master

Your commit was automatically rebased without conflicts.

[openjdk]

@iklam Pushed as commit 8c8d21d.

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