[8u60] RFR of backport for 8066875: VirtualSpace does not use large pages

[Tobias Hartmann]

Hi Thomas,

the code cache related changes look good to me (not a reviewer).

Best,
Tobias

On 26.03.2015 13:55, Thomas Schatzl wrote:
> Hi all,
> 
>   can I have reviews for the backport of "8066875: VirtualSpace does not
> use large pages" for 8u60? I also would like to have one review from the
> compiler team (cc'ed) since the change touches some compiler files.
> 
> It did only apply with minor changes, so I need re-reviews. The problem
> is that in jdk9 the code cache sizing has been changed. In particular:
> - dropped the hunk in code/codeCache.cpp because the code to determine
> memory sizes in 8u60 is much simpler i.e. .
> E.g. this change:
> --- a/src/share/vm/code/codeCache.cpp	Thu Jan 15 16:05:20 2015 +0100
> +++ b/src/share/vm/code/codeCache.cpp	Fri Jan 16 10:29:12 2015 +0100
> @@ -233,8 +233,8 @@
>  ReservedCodeSpace CodeCache::reserve_heap_memory(size_t size) {
>    // Determine alignment
>    const size_t page_size = os::can_execute_large_page_memory() ?
> -          MIN2(os::page_size_for_region(InitialCodeCacheSize, 8),
> -               os::page_size_for_region(size, 8)) :
> +          MIN2(os::page_size_for_region_aligned(InitialCodeCacheSize, 8),
> +               os::page_size_for_region_aligned(size, 8)) :
>            os::vm_page_size();
>    const size_t granularity = os::vm_allocation_granularity();
>    const size_t r_align = MAX2(page_size, granularity);
> 
> - fixed the code in heap.cpp because of the same change (JDK-8015774:
> Add support for multiple code heaps) is not in 8u60.
> 
> Note that this change is based on "8049864: TestParallelHeapSizeFlags
> fails with unexpected heap size"
> which is also out for review (on hotspot-gc-dev), and "8053995: Add
> method to WhiteBox to get vm_pagesize" which applies cleanly.
> 
> Full 8u60 changeset:
> http://cr.openjdk.java.net/~tschatzl/8066875-8u60/webrev.8u60/
> Fix changeset:
> http://cr.openjdk.java.net/~tschatzl/8066875-8u60/webrev.8u60-fix/
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8066875
> Original change:
> http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/4321214d5dbc
> 
> Testing: jprt
> 
> With that changeset in place, JDK-8058354 can be merged relatively
> easily, which is the goal of most of the recent backports.
> 
> Thanks,
>   Thomas
> 
> 
> 
> 
> 
>