On Mon, 15 Apr 2024 03:24:07 GMT, Vladimir Kozlov <k...@openjdk.org> wrote:
>> This is part of changes which try to reduce size of `nmethod` and `codeblob` >> data vs code in CodeCache. >> These changes reduced size of `nmethod` header from 288 to 232 bytes. From >> 304 to 248 in optimized VM: >> >> Statistics for 1282 bytecoded nmethods for C2: >> total in heap = 5560352 (100%) >> header = 389728 (7.009053%) >> >> vs >> >> Statistics for 1322 bytecoded nmethods for C2: >> total in heap = 8307120 (100%) >> header = 327856 (3.946687%) >> >> >> Several unneeded fields in `nmethod` and `CodeBlob` were removed. Some >> fields were changed from `int` to `int16_t` with added corresponding asserts >> to make sure their values are fit into 16 bits. >> >> I did additional cleanup after recent `CompiledMethod` removal. >> >> Tested tier1-7,stress,xcomp and performance testing. > > Vladimir Kozlov has updated the pull request incrementally with one > additional commit since the last revision: > > Union fields which usages do not overlap src/hotspot/share/code/codeBlob.cpp line 88: > 86: S390_ONLY(_ctable_offset(0) COMMA) > 87: _header_size((uint16_t)header_size), > 88: _frame_complete_offset((int16_t)frame_complete_offset), Rather than a raw cast, it would be better to use checked_cast here, or better yet, change the incoming parameter types to match the field type. That way, if the caller is passing a constant, the compiler can check it at compile time. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/18768#discussion_r1566601934
