On Sun, 28 Apr 2024 23:37:22 GMT, Vladimir Kozlov <k...@openjdk.org> wrote:
>> Move immutable nmethod's data from CodeCache to C heap. It includes >> `dependencies, nul_chk_table, handler_table, scopes_pcs, scopes_data, >> speculations`. It amounts for about 30% (optimized VM) of space in CodeCache. >> >> Use HotSpot's `os::malloc()` to allocate memory in C heap for immutable >> nmethod's data. Call `vm_exit_out_of_memory()` if allocation failed. >> >> Shuffle fields order and change some fields size from 4 to 2 bytes to avoid >> nmethod's header size increase. >> >> Tested tier1-5, stress,xcomp >> >> Our performance testing does not show difference. >> >> Example of updated `-XX:+PrintNMethodStatistics` output is in JBS comment. > > Vladimir Kozlov has updated the pull request incrementally with one > additional commit since the last revision: > > Address comments. Moved jvmci_data back to mutable data section. Looks good to me. Did you measure any impact on performance (potentially due to improved code density)? What's left for [JDK-7072317](https://bugs.openjdk.org/browse/JDK-7072317)? I wonder if the `CHECKED_CAST` changes shouldn't go into a separate RFE. ------------- Marked as reviewed by thartmann (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/18984#pullrequestreview-2027660174
