Hi, 

I am facing an error which I don't get why it is happening. The changes are just simple. I added 2 header words required in the RCHeader file of plan reference count. It has 8 global bits and 2 header words. I didn't change anything anywhere except that. I have pasted the error message. If anybody knows the issue, please get back to me. The stack says the problem is with the flushRememberedSets of mutator. Could you please also elaborate on what is flushremembered sets? 


hkrish4@hkrish4box:~/jikesrvm/examples$ ../dist/BaseBaseSWCount1_ia32-linux/rvm -verbose:gc:4 SimpleList
Key: (I)mmortal (N)onmoving (D)iscontiguous (E)xtent (F)raction
     HEAP_START 0x57000000
AVAILABLE_START 0x5c800000
       boot IN  0x57000000->0x66ffffff E 0x10000000
   immortal IND []
       meta  ND []
        los  ND []
     sanity  ND []
 non-moving  ND []
    sm-code  ND []
    lg-code  ND []
         rc  ND [0x67000000->0x673fffff]
      rclos  ND []
  AVAILABLE_END 0xa0000000
       HEAP_END 0xa0000000
================ MMTk Configuration ================
plan = org.mmtk.plan.swcount.fullheap.RC
HEADER_MARK_BITS = true
====================================================
Collection 1:        reserved = 20 MB (5120 pgs)      used = 20 MB (5120 pgs)      total = 20 MB (5120 pgs)
  Before Collection: used = 20.00 Mb = boot 0.00 Mb + immortal 0.00 Mb + meta 0.00 Mb + los 0.00 Mb + sanity 0.00 Mb + non-moving 0.00 Mb + sm-code 0.00 Mb + lg-code 0.00 Mb + rc 18.76 Mb + rclos 1.23 Mb
                     used = 5120 pgs = boot 0 pgs + immortal 0 pgs + meta 1 pgs + los 0 pgs + sanity 0 pgs + non-moving 0 pgs + sm-code 0 pgs + lg-code 0 pgs + rc 4803 pgs + rclos 316 pgs
Thread 5:     Processing GC in parallel
Thread 4:     Processing GC in parallel
   After Collection: used = 19.69 Mb = boot 0.00 Mb + immortal 0.00 Mb + meta 0.00 Mb + los 0.00 Mb + sanity 0.00 Mb + non-moving 0.00 Mb + sm-code 0.00 Mb + lg-code 0.00 Mb + rc 18.50 Mb + rclos 1.18 Mb
                     used = 5041 pgs = boot 0 pgs + immortal 0 pgs + meta 2 pgs + los 0 pgs + sanity 0 pgs + non-moving 0 pgs + sm-code 0 pgs + lg-code 0 pgs + rc 4736 pgs + rclos 303 pgs
                     reserved = 19 MB (5041 pgs)      used = 19 MB (5041 pgs)      total = 20 MB (5120 pgs)
    Collection time: 1198.64 ms
Live ratio 0.98
GCLoad     0.57
Heap adjustment factor is 1.50
GC Message: Heap changed from 20480KB to 30720KB
 [CC] Collection 2:        reserved = 19 MB (5042 pgs)      used = 19 MB (5042 pgs)      total = 30 MB (7680 pgs)
  Before Collection: used = 19.69 Mb = boot 0.00 Mb + immortal 0.00 Mb + meta 0.01 Mb + los 0.00 Mb + sanity 0.00 Mb + non-moving 0.00 Mb + sm-code 0.00 Mb + lg-code 0.00 Mb + rc 18.50 Mb + rclos 1.18 Mb
                     used = 5042 pgs = boot 0 pgs + immortal 0 pgs + meta 3 pgs + los 0 pgs + sanity 0 pgs + non-moving 0 pgs + sm-code 0 pgs + lg-code 0 pgs + rc 4736 pgs + rclos 303 pgs
JikesRVM: TROUBLE.  Got a signal (Segmentation fault; #11) from outside the VM's address space in thread 0xb59fdb40.
JikesRVM: TROUBLE.  Got a signal (Segmentation fault; #11) from outside the VM's address space in thread 0xb61feb40.
JikesRVM: UNRECOVERABLE trapped signal 11 (Segmentation fault)
handler stack 0
JikesRVM: UNRECOVERABLE trapped signal 11 (Segmentation fault)
handler stack 0
si->si_addr   (nil)
si->si_addr   (nil)
cs            0x00000073
cs            0x00000073
ds            0x0000007b
ds            0x0000007b
es            0x0000007b
es            0x0000007b
fs            0x00000000
fs            0x00000000
gs            0x00000033
gs            0x00000033
ss            0x0000007b
ss            0x0000007b
edi           0x003d0f00
edi           0x003d0f00
esi -- PR/VP  0x67082114
esi -- PR/VP  0x6704be94
ebp           0xb59fd2d8
ebp           0xb61fe2d8
esp -- SP     0x674b9ea8
esp -- SP     0x674a2ea8
ebx           0x0805dff4
ebx           0x0805dff4
edx           0x67e5824c
edx           0x670699cc
ecx           0x67e68824
ecx           0x67e68824
eax           0x67e5824c
eax           0x670699cc
eip           0x00000000
eip           0x00000000
trapno        0x0000000e
trapno        0x0000000e
err           0x00000014
err           0x00000014
eflags        0x00210202
eflags        0x00210202
fpregs        b46042a0
fpregs        93b2d88
oldmask       0x00020000
oldmask       0x00020000
cr2           0x00000000
cr2           0x00000000
fp0 0x00000000000000000000
fp0 0x00000000000000000000
fp1 0x00000000000000000000
fp1 0x00000000000000000000
fp2 0x00000000000000000000
fp2 0x00000000000000000000
fp3 0x00000000000000000000
fp3 0x00000000000000000000
fp4 0x00000000000000000000
fp4 0x00000000000000000000
fp5 0x00000000000000000000
fp5 0x00000000000000000000
fp6 0x00000000000000000000
fp6 0x00000000000000000000
fp7 0x00000000c4ce8ee3401d
fp7 0x00000000000000000000
JikesRVM: internal error
JikesRVM: internal error
-- Stack --
(0x674a2ee4 1716)   at [0x674a2ee4, 0x5b1defda] Lorg/mmtk/plan/SimpleMutator; collectionPhase(SZ)V at line 50
(0x674a2f10 1719)   at [0x674a2f10, 0x5b2ec6b8] Lorg/mmtk/plan/swcount/RCBaseMutator; collectionPhase(SZ)V at line 173
(0x674a2f68 2956)   at [0x674a2f68, 0x5b2ec9e4] Lorg/mmtk/plan/Phase; processPhaseStack(Z)V at line 486
(0x674a2f88 2954)   at [0x674a2f88, 0x5b1d9490] Lorg/mmtk/plan/Phase; beginNewPhaseStack(I)V at line 385
(0x674a2fa4 4199)   at [0x674a2fa4, 0x5b1c5d4a] Lorg/mmtk/plan/swcount/RCBaseCollector; collect()V at line 86
(0x674a2fc0 4182)   at [0x674a2fc0, 0x5b1e26b8] Lorg/mmtk/plan/ParallelCollector; run()V at line 50
(0x674a2fe0 9924)   at [0x674a2fe0, 0x5b33e4b8] Lorg/jikesrvm/mm/mminterface/CollectorThread; run()V at line 80
(0x674a3000 13115)   at [0x674a3000, 0x08050376] Lorg/jikesrvm/scheduler/RVMThread; startoff()V at line 2623
Exception in GC thread

-- Threads --
7-main-1-RUNNABLE             
2-daemon-system-1-RUNNABLE    
3-daemon-system-5-RUNNABLE    
4-daemon-system-collector-1-RUNNABLE
5-daemon-system-collector-1-RUNNABLE
6-daemon-system-collector-1-RUNNABLE


-- Locks in use --

lock availability stats: 0 locks allocated, 0 locks freed, 0 free locks
Dumping stack of active thread

Dumping stack for Thread #4
-- Stack --
(0x6749cd68 13180)   at [0x6749cd68, 0x5b2f3c88] Lorg/jikesrvm/scheduler/RVMThread; dumpVirtualMachine()V at line 5397
(0x6749cd84 2744)   at [0x6749cd84, 0x5b0c3a36] Ljava/lang/VMThrowable; fillInStackTrace(Ljava/lang/Throwable;)Ljava/lang/VMThrowable; at line 45
(0x6749cda4 159)   at [0x6749cda4, 0x5b32a018] Ljava/lang/Throwable; fillInStackTrace()Ljava/lang/Throwable; at line 498
(0x6749cdc4 163)   at [0x6749cdc4, 0x5b32a09c] Ljava/lang/Throwable; <init>(Ljava/lang/String;)V at line 159
(0x6749cde4 162)   at [0x6749cde4, 0x5b329c1a] Ljava/lang/Throwable; <init>()V at line 147
(0x6749ce00 167)   at [0x6749ce00, 0x5b31eb92] Ljava/lang/Exception; <init>()V at line 66
(0x6749ce1c 872)   at [0x6749ce1c, 0x5b257326] Ljava/lang/RuntimeException; <init>()V at line 64
(0x6749ce38 12830)   at [0x6749ce38, 0x5b347d44] Ljava/lang/ClassCastException; <init>()V at line 63
(0x6749ce78 8632)   at [0x6749ce78, 0x5b25987f] Lorg/jikesrvm/runtime/RuntimeEntrypoints; deliverHardwareException(II)V at line 781
(0x6749ce94 1)   at [0x6749ce94, 0x5b25987f] <hardware trap>
(0x674a2e64 12801)   at [0x674a2e64, 0x5b34f038] Lorg/jikesrvm/Callbacks; notifyExit(I)V at line 800
(0x674a2e80 3175)   at [0x674a2e80, 0x5b33a336] Lorg/jikesrvm/VM; sysExit(I)V at line 2385
(0x674a2e9c 13176)   at [0x674a2e9c, 0x00000000] Lorg/jikesrvm/scheduler/RVMThread; dumpStackAndDie(Lorg/vmmagic/unboxed/Address;)V at line 5337
   at [0x674a2ec0, 0x5b1dce37] <native frame>
(0x674a2ee4 1716)   at [0x674a2ee4, 0x5b1defda] Lorg/mmtk/plan/SimpleMutator; collectionPhase(SZ)V at line 50
(0x674a2f10 1719)   at [0x674a2f10, 0x5b2ec6b8] Lorg/mmtk/plan/swcount/RCBaseMutator; collectionPhase(SZ)V at line 173
(0x674a2f68 2956)   at [0x674a2f68, 0x5b2ec9e4] Lorg/mmtk/plan/Phase; processPhaseStack(Z)V at line 486