RFR 8230765: Implement nmethod barrier for x86_32 platforms
zgu at redhat.com
Mon Nov 25 20:35:13 UTC 2019
Please review this implementation of nmethod barrier for x86_32 platforms.
x86_32 implementation mirrors x86_64's. The only difference is where it
reads nmethod disarmed value.
Unlike 64-bits, 32-bits platform does not have a dedicated register for
current thread. So that it is cheaper to read disarmed value from global
location than from per-thread GC data.
Currently, only Shenandoah GC uses the implementation for its concurrent
class unloading. This implementation, along with Shenandoah concurrent
class unloading, has been baked in shenandoah/jdk repo for some time
now, they are ready for integration.
hotspot_gc with x86_64 and x86_32 JVM on Linux
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