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

Chris Plummer chris.plummer at oracle.com
Wed Mar 22 21:38:34 UTC 2017

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/osaix.cpp No comments.

src/os/bsd/vm/osbsd.cpp No comments. src/os/linux/vm/oslinux.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/osposix.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/ossolaris.cpp No comments. src/share/vm/prims/jvm.cpp L2812: // -Avoid truncating on 32-bit platforms if size is greater than UINTMAX 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

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