Make reserved_size for compressed class space and metaspace respect the ergo-initialized CompressedClassSpaceSize flag value

Man Cao manc at google.com
Thu Dec 7 18:42:58 UTC 2017


Hello,

This is a friendly ping. Could anyone review or sponsor this change? It's
just a two-liner change.

-Man

On Thu, Nov 30, 2017 at 2:03 PM, Man Cao <manc at google.com> wrote:

> I realized that the email attachment is probably dropped by the mailing
> list, so below is the inlined patch.
>
> --- old/src/hotspot/share/memory/metaspace.cpp 2017-11-29
> 14:56:59.017118444 -0800
> +++ new/src/hotspot/share/memory/metaspace.cpp 2017-11-29
> 14:56:58.657121375 -0800
> @@ -3321,9 +3321,6 @@
>    MinMetaspaceExpansion = align_down_bounded(MinMetaspaceExpansion,
> _commit_alignment);
>    MaxMetaspaceExpansion = align_down_bounded(MaxMetaspaceExpansion,
> _commit_alignment);
>
> -  CompressedClassSpaceSize = align_down_bounded(CompressedClassSpaceSize,
> _reserve_alignment);
> -  set_compressed_class_space_size(CompressedClassSpaceSize);
> -
>    // Initial virtual space size will be calculated at global_initialize()
>    size_t min_metaspace_sz =
>        VIRTUALSPACEMULTIPLIER * InitialBootClassLoaderMetaspaceSize;
> @@ -3341,6 +3338,8 @@
>                    min_metaspace_sz);
>    }
>
> +  CompressedClassSpaceSize = align_down_bounded(CompressedClassSpaceSize,
> _reserve_alignment);
> +  set_compressed_class_space_size(CompressedClassSpaceSize);
>  }
>
>  void Metaspace::global_initialize() {
>
> Best,
> Man
>
> On Wed, Nov 29, 2017 at 3:21 PM, Man Cao <manc at google.com> wrote:
>
>> Hello,
>>
>> This patch is a follow-up fix for https://bugs.openjdk.java.
>> net/browse/JDK-8087291
>>
>> This patch moves the call to set_compressed_class_space_size() after the
>> flag value for CompressedClassSpaceSize is ergo-initialized, fixing the
>> issue that the reserved size for compressed class space and metaspace is
>> excessively large when MaxMetaspaceSize is set to a small value. More
>> discussion about it is available here:
>> http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2
>> 017-November/025200.html
>>
>> This code patch is attached. Could anyone review and/or sponsor this
>> patch?
>>
>> Best,
>> Man
>>
>
>
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