tree 0fd0d46928f5a2730647c304130b6a606a752eb0
parent 52a8d214ca4c92db292f8ed15ee3b83a0c0629a3
author Protobuf Team Bot <protobuf-github-bot@google.com> 1681512958 -0700
committer Copybara-Service <copybara-worker@google.com> 1681512996 -0700

Switch upb_Arena_Fuse from a CAS based list insertion to an exchange based one

```
(Generated by http://go/benchy. Settings: --runs 20 --reference "srcfs" --perflab)

name                                           old cpu/op   new cpu/op   delta
BM_ArenaOneAlloc                                 18.2ns ± 2%  18.1ns ± 1%  -0.72%  (p=0.002 n=18+17)
BM_ArenaInitialBlockOneAlloc                     5.31ns ± 0%  5.30ns ± 1%    ~     (p=0.345 n=16+19)
BM_ArenaFuseUnbalanced/2...

***

PiperOrigin-RevId: 524406384