Re: Garbage collector: Out of memory (when running AWT/SWING code on arm-linux)

Andrew Haley wrote:
> ffileppo wrote:
>>> Hi guys,
>>>
>>> I'm getting the following error:
>>>
>>> GC Warning: Out of Memory! Returning NIL!
>>>
>>> when I try to run any AWT/SWING code compiled with arm-linux-gcj on my embedded box (PXA270 - 128MB Ram). (Other code just runs fine)
>>>
>>> For example this code:
>>>
>>> import javax.swing.*;
>>>
>>> public class SimpleFrame {
>>>   public static void main(String args[]) {
>>>     System.out.println("Check 1");
>>>     JFrame f = new JFrame("Simple Frame");
>>>     System.out.println("Check 2");
>>>     f.setSize(200,100);
>>>     f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
>>>     f.setVisible(true);
>>>   }
>>> }
>>>
>>> gives out of memory error after printing "Check 1".
>>> Trying with some other code I can see that the first AWT/SWING call causes this error.
>>>
>>> Any idea to fix / debug this problem?
> 
> I think I've found it.  The unwinder is infinitely looping 'til it runs out
> of memory.

And here it is:

(gdb) x state->frames[23].start_ip
0x40c13ac0 <_Jv_JNI_FindClass>: 0xe1a0c00d
(gdb) x state->frames[24].start_ip
0x40017f78 <__udivdi3>: 0xe92d4ff0
(gdb) x state->frames[22].start_ip
0x40c4c918 <java.lang.Class.initializeClass()void>:  0xe92d41f0
(gdb) x state->frames[23].start_ip
0x40c13ac0 <_Jv_JNI_FindClass>: 0xe1a0c00d
(gdb) x state->frames[20].start_ip
0x40c1653c <_Jv_Linker.verify_class(java.lang.Class)>: 0xe52de004
(gdb) x state->frames[21].start_ip
0x40c17ce8 <_Jv_Linker.wait_for_state(java.lang.Class, int)>:      0xe92d47f0
(gdb) x state->frames[22].start_ip
0x40c4c918 <java.lang.Class.initializeClass()void>:  0xe92d41f0
(gdb) x state->frames[23].start_ip
0x40c13ac0 <_Jv_JNI_FindClass>: 0xe1a0c00d
(gdb) x state->frames[24].start_ip
0x40017f78 <__udivdi3>: 0xe92d4ff0
(gdb) x state->frames[25].start_ip
0x4176b834 <GC_generic_push_regs>:      0xe59f3010

So here's the badness: the frame above _Jv_JNI_FindClass is wrong.  Here it's
found to be __udivdi3 but in reality it should be
Java_gnu_java_awt_peer_gtk_GtkToolkit_gtkInit.  I wonder if
libjava/classpath/native/jni/gtk-peer/gnu_java_awt_peer_gtk_GtkToolkit.c
has bad unwinder data.  It's also possible that _Jv_JNI_FindClass has bad
unwinder data.

Anyway, the kludge I suggested should work.

Andrew.