RFR: 8307958: Metaspace verification is slow causing extreme class unloading times [v2]

Tue May 23 08:07:04 UTC 2023

On Mon, 22 May 2023 18:27:07 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> This seems fine. To be clear, was most of the time spent in the ChunkManager::get_chunk() and return_chunk(), and maybe purge() calls, and not much in the split and merge chunks? I agree with adding SOMETIMES to all for consistency, but I hope we're not doing more of these operations that I assume should be infrequent.

Maybe it is overly defensive to add it to the split and get_chunk paths. The observed slowdown was for `purge()` calls, and more specifically the verification downstream of `~MetaspaceArena()`, which includes `return_chunk` and `merge()` as well as freelist `contains()` verification.

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PR Comment: https://git.openjdk.org/jdk/pull/14084#issuecomment-1558744966