On Tue, 13 May 2025 14:10:33 GMT, Joel Sikström <jsiks...@openjdk.org> wrote:
> Hello, > > The goal of this RFE is to separate Metaspace printing from GC printing. The > main reason Metaspace and GC printing is coupled the way it is right now is > because historically, the permanent generation (PermGen), which was replaced > by Metaspace, was part of the GC heap. Hence, it made sense to also print > info about the PermGen when printing the GC heap. > > With Metaspace replacing the PermGen, which uses memory that is separate from > the GC heap, the coupling has become more loose, raising the question if > Metaspace should be printed somewhere else (maybe when printing *other* > Metaspace stuff?). A reason to still print Metaspace when printing the heap > is that the GC is responsible for unloading classes and nmethods, which means > it makes sense to print Metaspace information in connection to when a GC is > performed. > > To better reflect the current state of the JVM, I propse we make the > following changes to separate Metaspace from GC printing: > * Move Metaspace printing from HeapInfoDCmd to MetaspaceDCmd. > * Move Metaspace printing from the "Heap:" section to "Metaspace:" section in > vmError.cpp (hs_err files, the VM.info jcmd and -XX:+PrintVMInfoAtExit). > * Use gc+exit instead of gc+heap+exit as tags for the LogTarget during exit > printing to reflect that it's not only the heap being printed. > * And the largest change in terms of LOC, separate Metaspace and GC Heap > prints in the before/after GC invocation(s) printing. This is also recorded > in a ring buffer, which is printed in vmError.cpp. > > Testing: > * GHA, Oracle's tier 1-4 > * Manuel inspection of printed content This pull request has now been integrated. Changeset: 85af573c Author: Joel Sikström <jsiks...@openjdk.org> URL: https://git.openjdk.org/jdk/commit/85af573cb6b5063c24f1efcbfb80bbace2883c7c Stats: 148 lines in 14 files changed: 60 ins; 31 del; 57 mod 8356848: Separate Metaspace and GC printing Reviewed-by: stefank, stuefe ------------- PR: https://git.openjdk.org/jdk/pull/25214
