RFR(S) 8193184: NMT: Report array class count in NMT summary

[coleen.phillimore at oracle.com]

Hi Zhengyu,

This looks really good.  The instanceKlass count does seem to belong to 
ClassLoaderData.

http://cr.openjdk.java.net/~zgu/8193184/webrev.00/src/hotspot/share/classfile/classLoaderData.hpp.udiff.html

+ static void inc_instance_classes(size_t count) {
+ Atomic::add(count, &_num_instance_classes);
+ }
+
+ static void dec_instance_classes(size_t count) {
+ assert(count <= _num_instance_classes, "Sanity");
+ Atomic::sub(count, &_num_instance_classes);
+ }
+
+ static void inc_array_classes(size_t count) {
+ Atomic::add(count, &_num_array_classes);
+ }
+
+ static void dec_array_classes(size_t count) {
+ assert(count <= _num_array_classes, "Sanity");
+ Atomic::sub(count, &_num_array_classes);
+ }


Can you move these functions to classLoaderData.inline.hpp?

Maybe you should add an NMT test for this to verify the output?

Thanks,
Coleen


On 2/2/18 3:28 PM, Zhengyu Gu wrote:
> Please review this patch that adds array class count to NMT report, so 
> the class count can closely match the output from GC.class_stats.
>
> For example:
> Summary:
> -                     Class (reserved=1069781KB, committed=1069269KB)
>                             (classes #3362)
>                             (  instance classes# 3105, array classes#257)
>
> Summary diff:
> -                     Class (reserved=1071843KB +2061KB, 
> committed=1070051KB +781KB)
>                             (classes #3405 +43)
>                             (  instance classes# 3143 +38, array 
> classes#262 +5)
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8193184
> Webrev: http://cr.openjdk.java.net/~zgu/8193184/webrev.00/
>
> Test:
>   hotspot_tier1_runtime on Linux 64 (fastdebug and release)
>
> Thanks,
>
> -Zhengyu
>