diff -ru jdk-1_5_0_11.b4/hotspot/src/os/bsd/vm/os_bsd.cpp jdk-1_5_0_11.ahj12/hotspot/src/os/bsd/vm/os_bsd.cpp
--- jdk-1_5_0_11.b4/hotspot/src/os/bsd/vm/os_bsd.cpp	Sun Feb 18 16:13:42 2007
+++ jdk-1_5_0_11.ahj12/hotspot/src/os/bsd/vm/os_bsd.cpp	Tue Feb 20 22:29:27 2007
@@ -2706,7 +2833,30 @@
 
 // this is called _after_ the global arguments have been parsed
 jint os::init_2(void) {
-  
+
+  // XXX ugly hack for 32-bit address space, since we know the
+  // java heap is allocated with mmap() not sbrk():
+#if SSIZE_MAX == 0x7fffffff
+  // set the max datasegment size to something reasonable
+  // complain if getrlimit/setrlimit fails but continue regardless. 
+  struct rlimit dseg_size;
+  int status = getrlimit(RLIMIT_DATA, &dseg_size);
+  if (status != 0) {
+     if (PrintMiscellaneous && (Verbose || WizardMode))
+        perror("os::init_2 getrlimit failed");
+  } else {
+     if (dseg_size.rlim_max > 1000 * 1024 * 1024) {
+        dseg_size.rlim_max = 500 * 1024 * 1024;
+        dseg_size.rlim_cur = 500 * 1024 * 1024;
+        status = setrlimit(RLIMIT_DATA, &dseg_size);
+        if (status != 0) {
+           if (PrintMiscellaneous && (Verbose || WizardMode))
+               perror("os::init_2 setrlimit failed");
+        }
+     }
+  }
+#endif
+
   // Allocate a single page and mark it as readable for safepoint polling
   if( SafepointPolling ) {
     address polling_page = (address) ::mmap(NULL, page_size,