Request for Comments: Backport of JDK-8166317: InterpreterCodeSize should be computed

[David Holmes]

Hi Leslie,

Patches must be submitted using OpenJDK infrastructure for legal 
purposes. Please get someone to host your patch on cr.openjdk.java.net, 
or else (if it is small) inline it in your email.

Thanks,
David

On 17/09/2018 5:26 PM, Leslie Zhai wrote:
> Hi all,
> 
> I would like to backport the fix for:
> 
> https://bugs.openjdk.java.net/browse/JDK-8166317
> 
> To OpenJDK 8 updates dev:
> 
> http://hg.openjdk.java.net/jdk8u/jdk8u-dev
> 
> The fix is mostly the same as the version that was committed in 10 
> except that there are:
> 
> * no _code_end or _data_end private members in the 
> hotspot/src/share/vm/code/codeBlob.hpp
> 
> * no get_code_heap(...) function in the 
> hotspot/src/share/vm/code/codeCache.cpp
> 
> in OpenJDK 8, so I just:
> 
> * use _data_offset private member to update code_end() and data_end() in 
> the adjust_size
> 
> * use _heap private member to call deallocate_tail(...) function
> 
> * leave the opportunity for MIPS if need to override 
> `g1_barrier_stubs_init`
> 
> Here is the patch:
> 
> https://raw.githubusercontent.com/xiangzhai/jdk8u-dev/master/JDK-8166317-Backport.patch 
> 
> 
> Please review it and give me some comments, thanks a lot!
> 
> ----- 8< -------- 8< -------- 8< -------- 8< -------- 8< -------- 8< ---
> 
> $ jtreg -vmoptions:"-XX:+UnlockDiagnosticVMOptions 
> -XX:+PrintInterpreter" -dir:/home/loongson/zhaixiang/jdk8-mips/jdk/test 
> -verbose:all 
> -exclude:/home/loongson/zhaixiang/jdk8-mips/jdk/test/ProblemList.txt 
> -conc:2 -Xmx512m -a -ignore:quiet -timeoutFactor:5 -agentvm 
> -testjdk:/home/loongson/zhaixiang/jdk8-mips/build/linux-mips64-normal-server-release/images/j2sdk-image 
> com/sun/jdi/AccessSpecifierTest.java
> 
> * Applied the patch, theres no more waste in the CodeCache after 
> interpreter generation and the output of -XX:+PrintInterpreter looks as 
> follows for jdk8u-dev on mips64el:
> 
> Agent[0].stdout: 
> ----------------------------------------------------------------------
> Agent[0].stdout: Interpreter
> Agent[0].stdout:
> Agent[0].stdout: code size        =    163K bytes
> Agent[0].stdout: total space      =    163K bytes
> Agent[0].stdout: wasted space     =      0K bytes
> Agent[0].stdout:
> Agent[0].stdout: # of codelets    =    263
> Agent[0].stdout: avg codelet size =    636 bytes
> 
> ...
> 
> AccessSpecifierTest: passed
> 
> * Dropped the patch, the used/wasted ratio for the interpreter part of 
> the code cache (which can be dumped with -XX:+PrintInterpreter) looks as 
> follows for jdk8u-dev on mips64el:
> 
> Agent[0].stdout: 
> ----------------------------------------------------------------------
> Agent[0].stdout: Interpreter
> Agent[0].stdout:
> Agent[0].stdout: code size        =    163K bytes
> Agent[0].stdout: total space      =    499K bytes
> Agent[0].stdout: wasted space     =    336K bytes
> Agent[0].stdout:
> Agent[0].stdout: # of codelets    =    263
> Agent[0].stdout: avg codelet size =    636 bytes
> 
> ...
> 
> STDOUT:
> #
> # A fatal error has been detected by the Java Runtime Environment:
> #
> #  Internal Error (interpreter.hpp:109), pid=23725, tid=0x000000fff2f9b1f0
> #  guarantee(codelet_size > 0 && (size_t)codelet_size > 2*K) failed: not 
> enough space for interpreter generation
> 
> 
> Thanks,
> 
> Leslie Zhai
> 
>