Intermittent code cache full messages in main (500USD Bounty)

[lihaoyi]

---

From the maintainer Li Haoyi: I'm putting a 500USD bounty on this issue, payable by bank transfer on a merged PR fixing this.

See https://github.com/orgs/com-lihaoyi/discussions/6 for other bounties and the terms and conditions that bounties operate under

---

e.g.

[12107] [info] compiling 1 Scala source to /Users/lihaoyi/Github/mill/out/core/server/test/semanticDbData.dest/classes ..
OpenJDK 64-Bit Server VM warning: CodeHeap 'non-profiled nmethods' is full. Compiler has been disabled.
OpenJDK 64-Bit Server VM warning: Try increasing the code heap size using -XX:NonProfiledCodeHeapSize=
[99.636s][warning][codecache] CodeHeap 'non-profiled nmethods' is full. Compiler has been disabled.
[99.636s][warning][codecache] Try increasing the code heap size using -XX:NonProfiledCodeHeapSize=
CodeHeap 'non-profiled nmethods': size=120032Kb used=119871Kb max_used=119871Kb free=161Kb
 bounds [0x0000000112248000, 0x0000000119780000, 0x0000000119780000]
CodeHeap 'profiled nmethods': size=120016Kb used=99387Kb max_used=120016Kb free=20628Kb
 bounds [0x000000010a780000, 0x0000000111cb4000, 0x0000000111cb4000]
CodeHeap 'non-nmethods': size=5712Kb used=1932Kb max_used=2116Kb free=3779Kb
 bounds [0x0000000111cb4000, 0x0000000111f24000, 0x0000000112248000]
 total_blobs=69508 nmethods=68283 adapters=1132
 compilation: disabled (not enough contiguous free space left)
              stopped_count=1, restarted_count=0
 full_count=1

Seems to have started only after merging the Scala 3 update. Probably leaking a classloader somewhere.

The completion criteria is a consistent reproduction, and a PR which can be shown to fix the issue.

[gamlerhart]

I had this one on 0.12.7 as well, after upgrading from 0.12.5.

However, I had it once, and then couldn't reproduce it.