On Wed, 22 Mar 2023 09:46:04 GMT, Roman Kennke <rken...@openjdk.org> wrote:
>> src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp line 670: >> >>> 668: get_thread (scrReg); // beware: clobbers ICCs >>> 669: movptr(Address(boxReg, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)), >>> scrReg); >>> 670: xorptr(boxReg, boxReg); // set icc.ZFlag = 1 to >>> indicate success >> >> Should this be under `if (UseFastLocking)`? > > I don't think so, unless we also want to change all the stuff in x86_32.ad to > not fetch the thread before calling into fast_unlock(). However, I think it > is a nice and useful change. I could break it out of this PR and get it > reviewed separately, it is a side-effect of the new locking impl insofar as > we always require a thread register, and allocate&fetch it before going into > fast_lock(). I missed that it is under #ifndef LP64. Yes, it make since since you are now passing `thread` in register. And why we need to `get_thread()` at line 708 if we already have it? It is still hard to follow this 32-bit code. What each register is holding, what is value `3` and why we don't have checks similar to LP64 code after CAS? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/10907#discussion_r1145223128
