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/memory/heap.hpp line 58: > 56: void set_length(size_t length) { > 57: LP64_ONLY( assert(((length >> 32) == 0), "sanity"); ) > 58: _header._length = (uint32_t)length; Suggestion: _header._length = checked_cast<uint32_t>length; src/hotspot/share/memory/heap.hpp line 63: > 61: // Accessors > 62: void* allocated_space() const { return (void*)(this + > 1); } > 63: size_t length() const { return > (size_t)_header._length; } This cast looks unnecessary. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/18768#discussion_r1566784458 PR Review Comment: https://git.openjdk.org/jdk/pull/18768#discussion_r1566784587