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src/os/aix/vm/os_aix.cpp

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rev 12334 : 8169373: Work around linux NPTL stack guard error.
Summary: Also skip OS guard page for compiler thread, merge similar code on linux platforms, and streamline OS guard page handling on linuxs390, linuxppc, aixppc.
Reviewed-by: dholmes

@@ -850,42 +850,45 @@
 bool os::create_thread(Thread* thread, ThreadType thr_type,
                        size_t req_stack_size) {
 
   assert(thread->osthread() == NULL, "caller responsible");
 
-  // Allocate the OSThread object
+  // Allocate the OSThread object.
   OSThread* osthread = new OSThread(NULL, NULL);
   if (osthread == NULL) {
     return false;
   }
 
-  // set the correct thread state
+  // Set the correct thread state.
   osthread->set_thread_type(thr_type);
 
   // Initial state is ALLOCATED but not INITIALIZED
   osthread->set_state(ALLOCATED);
 
   thread->set_osthread(osthread);
 
-  // init thread attributes
+  // Init thread attributes.
   pthread_attr_t attr;
   pthread_attr_init(&attr);
   guarantee(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) == 0, "???");
 
   // Make sure we run in 1:1 kernel-user-thread mode.
   if (os::Aix::on_aix()) {
     guarantee(pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM) == 0, "???");
     guarantee(pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED) == 0, "???");
-  } // end: aix
+  }
 
   // Start in suspended state, and in os::thread_start, wake the thread up.
   guarantee(pthread_attr_setsuspendstate_np(&attr, PTHREAD_CREATE_SUSPENDED_NP) == 0, "???");
 
-  // calculate stack size if it's not specified by caller
+  // Calculate stack size if it's not specified by caller.
   size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
   pthread_attr_setstacksize(&attr, stack_size);
 
+  // libc guard page
+  pthread_attr_setguardsize(&attr, os::Aix::default_guard_size(thr_type));
+
   pthread_t tid;
   int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
 
   char buf[64];
   if (ret == 0) {

@@ -897,11 +900,11 @@
   }
 
   pthread_attr_destroy(&attr);
 
   if (ret != 0) {
-    // Need to clean up stuff we've allocated so far
+    // Need to clean up stuff we've allocated so far.
     thread->set_osthread(NULL);
     delete osthread;
     return false;
   }
 

@@ -3034,10 +3037,22 @@
     }
   }
   return chained;
 }
 
+size_t os::Aix::default_guard_size(os::ThreadType thr_type) {
+  // Creating guard pages is very expensive. Java thread has HotSpot
+  // guard pages, so only enable libc guard pages for non-Java threads.
+  //
+  // Aix can have different page sizes for stack (4K) and heap (64K).
+  // As Hotspot knows only one page size, we assume the stack has
+  // the same page size as the heap. Returning page_size() here can
+  // cause 16 guard pages which we want to avoid.  Thus we return 4K
+  // which will be rounded to the real page size by the OS.
+  return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : 4*K);
+}
+
 struct sigaction* os::Aix::get_preinstalled_handler(int sig) {
   if (sigismember(&sigs, sig)) {
     return &sigact[sig];
   }
   return NULL;
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