Off-heap object space
Khanh Nguyen
ktruong.nguyen at gmail.com
Sat Jan 16 01:54:23 UTC 2016
Hi,
I want to implement an off-heap, non-GC, non-contiguous object space. Of
course my naive approach is to call os::malloc or the existing macro
AllocateHeap(). Also I did turn the compressed oops flags off. But I'm
facing this undeterministic issue: randomly the JVM crashes. That is,
sometimes my program can successfully run (with the correct result). And
sometimes it crashes (in library code)
Partial crash log is this:
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00007fd71102681d, pid=6741, tid=140562059818752
#
# JRE version: OpenJDK Runtime Environment (8.0) (build
1.8.0-internal-debug-khanhtn1_2016_01_15_17_06-b00)
# Java VM: OpenJDK 64-Bit Server VM (25.0-b70-debug interpreted mode
linux-amd64 )
# Problematic frame:
# j
java.util.HashMap.putVal(ILjava/lang/Object;Ljava/lang/Object;ZZ)Ljava/lang/Object;+56
#
# Core dump written. Default location:
/lv_scratch/scratch/khanh/openjdk8/core or core.6741
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
#
--------------- T H R E A D ---------------
Current thread (0x00007fd72000a800): JavaThread "main" [_thread_in_Java,
id=6742, stack(0x00007fd72794f000,0x00007fd727a50000)]
siginfo:si_signo=SIGSEGV: si_errno=0, si_code=2 (SEGV_ACCERR),
si_addr=0x00007fd723ee00be
Registers:
RAX=0x00007fd6110fc818, RBX=0x00007fd0ae129248, RCX=0x0000000000000000,
RDX=0x0000003fe88800be
RSP=0x00007fd727a4e428, RBP=0x00007fd727a4e480, RSI=0x00007fd727a4e3b8,
RDI=0x0000000001200020
R8 =0x0000000000000000, R9 =0x0000000000000024, R10=0x00007f973b660000,
R11=0x00007fd727a4e390
R12=0x00007fd711000564, R13=0x00007fd0ae124bb3, R14=0x00007fd727a4e4f0,
R15=0x00007fd72000a800
RIP=0x00007fd71102681d, EFLAGS=0x0000000000010206,
CSGSFS=0x0000000000000033, ERR=0x0000000000000006
TRAPNO=0x000000000000000e
Stack: [0x00007fd72794f000,0x00007fd727a50000], sp=0x00007fd727a4e428,
free space=1021k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native
code)
j
java.util.HashMap.putVal(ILjava/lang/Object;Ljava/lang/Object;ZZ)Ljava/lang/Object;+56
j
java.util.HashMap.put(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;+9
j EmptyMethod.generateHashMap()Ljava/util/HashMap;+44
j EmptyMethod.runTest(I)V+24
j EmptyMethod.main([Ljava/lang/String;)V+97
v ~StubRoutines::call_stub
V [libjvm.so+0x823762] JavaCalls::call_helper(JavaValue*, methodHandle*,
JavaCallArguments*, Thread*)+0x680
V [libjvm.so+0xaaae44] os::os_exception_wrapper(void (*)(JavaValue*,
methodHandle*, JavaCallArguments*, Thread*), JavaValue*, methodHandle*,
JavaCallArguments*, Thread*)+0x3a
V [libjvm.so+0x8230db] JavaCalls::call(JavaValue*, methodHandle,
JavaCallArguments*, Thread*)+0x7d
V [libjvm.so+0x837185] jni_invoke_static(JNIEnv_*, JavaValue*, _jobject*,
JNICallType, _jmethodID*, JNI_ArgumentPusher*, Thread*)+0x1ca
V [libjvm.so+0x84d31e] jni_CallStaticVoidMethod+0x385
C [libjli.so+0x8012] JavaMain+0x89a
--------------- P R O C E S S ---------------
Java Threads: ( => current thread )
0x00007fd72014c000 JavaThread "Service Thread" daemon [_thread_blocked,
id=6765, stack(0x00007fd0a9e37000,0x00007fd0a9f38000)]
0x00007fd720142800 JavaThread "Signal Dispatcher" daemon
[_thread_blocked, id=6764, stack(0x00007fd0a9f38000,0x00007fd0aa039000)]
0x00007fd7200e9000 JavaThread "Finalizer" daemon [_thread_blocked,
id=6763, stack(0x00007fd110058000,0x00007fd110159000)]
0x00007fd7200e6800 JavaThread "Reference Handler" daemon
[_thread_blocked, id=6762, stack(0x00007fd0aa039000,0x00007fd0aa13a000)]
=>0x00007fd72000a800 JavaThread "main" [_thread_in_Java, id=6742,
stack(0x00007fd72794f000,0x00007fd727a50000)]
Other Threads:
0x00007fd7200db800 VMThread [stack:
0x00007fd0aa13a000,0x00007fd0aa23b000] [id=6761]
0x00007fd720150000 WatcherThread [stack:
0x00007fd0a9d36000,0x00007fd0a9e37000] [id=6766]
VM state:not at safepoint (normal execution)
VM Mutex/Monitor currently owned by a thread: None
Heap:
PSYoungGen total 5120K, used 2088K [0x00007fd611000000,
0x00007fd611b00000, 0x00007fd711000000)
eden space 4096K, 25% used
[0x00007fd611000000,0x00007fd61110a278,0x00007fd611400000)
from space 1024K, 100% used
[0x00007fd611400000,0x00007fd611500000,0x00007fd611500000)
to space 1536K, 0% used
[0x00007fd611980000,0x00007fd611980000,0x00007fd611b00000)
ParOldGen total 512512K, used 1128K [0x00007fd411000000,
0x00007fd430480000, 0x00007fd611000000)
object space 512512K, 0% used
[0x00007fd411000000,0x00007fd41111a0c0,0x00007fd430480000)
Metaspace used 3255K, capacity 4108K, committed 4352K, reserved 8192K
Card table byte_map: [0x00007fd7256e8000,0x00007fd726ee9000] byte_map_base:
0x00007f973b660000
Marking Bits: (ParMarkBitMap*) 0x00007fd728f79340
Begin Bits: [0x00007fd0b0000000, 0x00007fd0bc000000)
End Bits: [0x00007fd0bc000000, 0x00007fd0c8000000)
Polling page: 0x00007fd7291f5000
CodeCache: size=245760Kb used=1439Kb max_used=1439Kb free=244320Kb
bounds [0x00007fd711000000, 0x00007fd711270000, 0x00007fd720000000]
total_blobs=189 nmethods=0 adapters=164
compilation: disabled (interpreter mode)
Using gdb doesn't show anything interesting unfortunately
#2 0x00007fd023d393a3 in os::abort (dump_core=true) at
/scratch/khanh/openjdk8/hotspot/src/os/linux/vm/os_linux.cpp:1563
#3 0x00007fd023efacdd in VMError::report_and_die (this=0x7fd023293d00) at
/scratch/khanh/openjdk8/hotspot/src/share/vm/utilities/vmError.cpp:1078
#4 0x00007fd023d453d9 in JVM_handle_linux_signal (sig=11,
info=0x7fd023293fb0, ucVoid=0x7fd023293e80, abort_if_unrecognized=1) at
/scratch/khanh/openjdk8/hotspot/src/os_cpu/linux_x86/vm/os_linux_x86.cpp:534
#5 0x00007fd023d3eebf in signalHandler (sig=11, info=0x7fd023293fb0,
uc=0x7fd023293e80) at
/scratch/khanh/openjdk8/hotspot/src/os/linux/vm/os_linux.cpp:4278
#6 <signal handler called>
#7 0x00007fd00d02681d in ?? ()
#8 0x00007fcf0d0feee0 in ?? ()
#9 0x0000000000000002 in ?? ()
#10 0x00007fc9e95c9c58 in ?? ()
#11 0x00007fd023294440 in ?? ()
#12 0x00007fca09c71bb0 in ?? ()
#13 0x00007fd0232944f0 in ?? ()
#14 0x00007fca09c74e30 in ?? ()
#15 0x0000000000000000 in ?? ()
So my questions, specifically, are
1) Why SEGV_ACCERR? And any idea of where the problem might be?
2) In theory, it should be straightforward for me to have an off-heap space
where I can allocate objects in. I don't understand why there is a random
crash like what I have. I mean if I violate some implicit rules in Hotspot,
my program should fail always.
Any pointers/suggestions are greatly appreciated.
Thank you,
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