On Fri, 26 Apr 2024 21:16:03 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, jvmci_data`. 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. Bail out compilation 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. src/hotspot/share/code/nmethod.cpp line 1332: > 1330: #if INCLUDE_JVMCI > 1331: _speculations_offset = _scopes_data_offset; > 1332: _jvmci_data_offset = _speculations_offset; Why not use 0 for all these? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/18984#discussion_r1581642931
