Request for reviews (S): 6892186: 6896084: VM does not reserve protected page below heap for compressed oops implicit null checks
Christian.Thalinger at Sun.COM
Thu Oct 29 01:50:14 PDT 2009
On Wed, 2009-10-28 at 16:13 -0700, Vladimir Kozlov wrote:
> Fixed 6896084: VM does not reserve protected page below heap for compressed oops implicit null checks
> VM should reserve protected page below heap for compressed oops
> implicit null checks in compiled code (see 6716785).
> After zero based compressed oops changes (6791178) the page is
> not reserved because undefined narrow_oop_base (NULL by default)
> is used in ReservedHeapSpace() to determine if the page is needed.
> Set narrow_oop_base and narrow_oop_use_implicit_null_checks
> values according to compressed oops encoding mode in
> Universe::preferred_heap_base() which is called before
> ReservedHeapSpace() constructors.
Using size_t for base (which is an address) feels a little strange but
otherwise looks good.
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