RFR: 8334564: VM startup: fatal error: FLAG_SET_ERGO cannot be used to set an invalid value for NonNMethodCodeHeapSize

[Lutz Schmidt]

CodeHeap segment sizes are aligned to page size multiples. This can result in the non-nmethod segment receiving size 0 (zero). Range checking during FLAG_SET_ERGO processing detects that and raises an error, preventing the vm from starting.

This fix increases the minimum size of the non-nmethod segment to page size, preventing it from being rounded down to zero.

Verified by manual testing. Nightly tests (mainly to discover unexpected side effects) pending.

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Commit messages:
 - VM startup: fatal error: FLAG_SET_ERGO cannot be used to set an invalid value for NonNMethodCodeHeapSize

Changes: https://git.openjdk.org/jdk/pull/19812/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19812&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8334564
  Stats: 5 lines in 1 file changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/19812.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19812/head:pull/19812

PR: https://git.openjdk.org/jdk/pull/19812