(RFR)(S)(10): 8176768: hotspot ignores PTHREAD_STACK_MIN when creating new threads

[Chris Plummer]

Hello,

Sorry to beat a dead horse here, but in addition to Dan's recommended 
fixes, I also reworked how I check for overflow when aligning up thanks 
to a suggestion from David:

http://cr.openjdk.java.net/~cjplummer/8176768/webrev.03/webrev.hotspot/

src/os/linux/vm/os_linux.cpp:

  726   // behaviour. However, be careful not to end up with a size
  727   // of zero due to overflow. Don't add the guard page in that case.
  728   size_t guard_size = os::Linux::default_guard_size(thr_type);
  729   if (stack_size <= SIZE_MAX - guard_size) {
  730     stack_size += guard_size;
  731   }
  732   assert(is_size_aligned(stack_size, os::vm_page_size()), 
"stack_size not aligned");

src/os/posix/vm/os_posix.cpp:

1260   // pthread_attr_setstacksize() may require that the size be 
rounded up to the OS page size.
1261   // Be careful not to round up to 0. Align down in that case.
1262   if (stack_size <= SIZE_MAX - vm_page_size()) {
1263     stack_size = align_size_up(stack_size, vm_page_size());
1264   } else {
1265     stack_size = align_size_down(stack_size, vm_page_size());
1266   }

Dan's comments below for reference:
> src/os/aix/vm/os_aix.cpp
>       No comments.
>
> src/os/bsd/vm/os_bsd.cpp
>       No comments.
>
> src/os/linux/vm/os_linux.cpp
>       L729:   // In that cast just subract the page size to get the
> maximum possible stack size.
>           Typo: 'cast' -> 'case'
>           Typo: 'subract' -> 'subtract' (Thomas also commented on it)
>
> src/os/posix/vm/os_posix.cpp
>       L263:   // aligning up could have resulted in the size being 0. In
> that case just subract the
>           Nit: 'aligning' -> 'Aligning' (since it's a sentence)
>           Typo: 'subract' -> 'subtract'
>
> src/os/solaris/vm/os_solaris.cpp
>       No comments.
>
> src/share/vm/prims/jvm.cpp
>       L2812:       // -Avoid truncating on 32-bit platforms if size is
> greater than UINT_MAX
>           Nit: needs a period at the end like L2813.
>
> test/runtime/Thread/TooSmallStackSize.java
>       No comments.
>
> test/runtime/Thread/TestThreadStackSizes.java
>       L26:  * @summary Test user threads with various stacks sizes.
>           Typo?: "stacks sizes" -> "stack sizes"
>
>       L36:         super(null, null, "TestThreadStackSizes"+stackSize,
> stackSize);
>           Nit: spaces around the "+".
>
>       L46:             TestThreadStackSizes testThreadStackSize  = new
> TestThreadStackSizes(stackSize);
>           Nit: extra space before '='.
thanks

Chris