src/os_cpu/aix_ppc/vm/os_aix_ppc.cpp

rev 12307 : 8169373: Work around linux NPTL stack guard error.
Summary: Also streamline OS guard page handling on linuxs390, linuxppc, aixppc.
rev 12308 : imported patch new_os_guard_for_java_thread.patch

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  }
  
  ////////////////////////////////////////////////////////////////////////////////
  // thread stack
  
! // These sizes exclude OS stack guard pages, but include
! // the VM guard pages.
! size_t os::Posix::_compiler_thread_min_stack_allowed = 128 * K;
! size_t os::Posix::_java_thread_min_stack_allowed = 128 * K;
! size_t os::Posix::_vm_internal_thread_min_stack_allowed = 128 * K;
  
  // Return default stack size for thr_type.
  size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
    // Default stack size (compiler thread needs larger stack).
    size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
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  }
  
  ////////////////////////////////////////////////////////////////////////////////
  // thread stack
  
! // Minimum usable stack sizes required to get to user code. Space for VM
! // guard pages is added later.
! size_t os::Posix::_compiler_thread_min_stack_allowed = 192 * K;
! size_t os::Posix::_java_thread_min_stack_allowed = 64 * K;
! size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
  
  // Return default stack size for thr_type.
  size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
    // Default stack size (compiler thread needs larger stack).
    size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
*** 555,565 ****
    // 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 ? 0 : 4*K);
  }
  
  /////////////////////////////////////////////////////////////////////////////
  // helper functions for fatal error handler
  
--- 555,565 ----
    // 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 == os::compiler_thread) ? 0 : 4*K);
  }
  
  /////////////////////////////////////////////////////////////////////////////
  // helper functions for fatal error handler