Fix code cache allocation with large pages enabled

[SajinaKandy]

Code cache allocation sizes are calculated and rounded up to the page size available on the system. When large pages/huge pages are enabled, and page size >= 1GB, this can cause the code cache size calculation to go wrong.
When codecachetotal is lesser than the page size, it makes the size of code cache segment bigger than the total code cache size (default 256MB for a 64-bit VM).
If large pages are enabled, page size should be recalculated to a smaller value if required. Also a warning message should be printed in the verbose output.

Closes: ##18274

[SajinaKandy]

On a machine with 2M large page size,
java -Xcodecachetotal1M -Xcodecache1M "-Xjit:verbose={codecache,compilePerformance}" MemoryUsageTest

will output the following in the verbose output:

#CODECACHE:  Warning:Using page size 4096 instead of large page size 2097152
#CODECACHE:  The code cache repository was allocated between addresses 00007FC98DE00000 and 00007FC991E00000 to be near the VM/JIT modules to avoid trampolines
#CODECACHE:  allocated code cache segment of size 1048576
#CODECACHE:  allocateCodeCacheRepository: size=1048576 heapBase=00007FC990251000 heapAlloc=00007FC990251008 heapTop=00007FC990351000
#CODECACHE:  carved size=1048568 range: 00007FC990251008-00007FC990351000
#CODECACHE:  CodeCache allocated 00007FC98C0CCEB0 @ 00007FC990251008-00007FC990351000 HelperBase:00007FC990350260

The output of the memory usage for JIT Code cache is:

Name: JIT code cache
Type: Non-heap memory
Usage: init = 1048576(1024K) used = 1041568(1017K) committed = 1048576(1024K) max = 1048576(1024K)
Peak Usage: init = 1048576(1024K) used = 1048000(1023K) committed = 1048576(1024K) max = 1048576(1024K)
Collection Usage: null

In order to do this test I removed the lines which imposes a 2MB minimum on the code cache total size:

openj9/runtime/compiler/control/J9Options.cpp

Lines 1696 to 1697 in 06c3abc

	if (ccTotalSize < 2048)
	ccTotalSize = 2048;

Next Action: Test on a machine with 1GB huge page size.

[mpirvu]

See the inline comments

[mpirvu]

For me this PR does not build locally.

/home/mpirvu/FullJava11/openj9-openjdk-jdk11/openj9/runtime/gc_modron_startup/mmparseXXgc.cpp:645:31: error: 'class MM_Configuration' has no member named '_packetListSplitForced'
  645 |    extensions->configuration->_packetListSplitForced = true;

It's possible that there is a mismatch between this openj9 code and the omr one.
@SajinaKandy please rebase this branch.

[mpirvu]

The code works at least when 4KB and 1GB pages are available.
I'll see if I can get 4KB, 2 MB and 1GB pages all at the same time.

[SajinaKandy]

@mpirvu Its great you are able to test this. I have rebased my work.

[mpirvu]

Since not many people have verbose logs enabled, I think we should also add a trace point for this rare case (basically under the same conditions the verbose line is printed).
Moreover, this change needs to be documented.

[mpirvu]

I cannot get both 2MB and 1GB large pages enabled on the system. It's either one or the other.
The proposed code should fix the problem seen by the customer.

[mpirvu]

LGTM

[mpirvu]

jenkins compile all jdk21

[mpirvu]

jenkins compile alinux64 jdk21

[mpirvu]

jenkins test sanity zlinux jdk17

[mpirvu]

@SajinaKandy don't forget to create an issue at https://github.com/eclipse-openj9/openj9-docs to describe the change in behavior when large pages are used.

[SajinaKandy]

@mpirvu Raised the doc issue: eclipse-openj9/openj9-docs#1206