On Mon, 27 Jun 2022 08:15:01 GMT, Yi Yang <yy...@openjdk.org> wrote:
>> It seems that calculation of
>> MemoryMXBean.getNonHeapMemoryUsage(jmm_GetMemoryUsage) is wrong.
>>
>> Currently,
>> `NonHeapUsage=CodeCache+Metaspace(ClassTypeSpace+NonClassTypeSpace)+CompressedClassSpace(ClassTypeSpace)`
>>
>> ==> CodeHeap 'non-nmethods' 1532544 (Used)
>> ==> CodeHeap 'profiled nmethods' 0
>> ==> CodeHeap 'non-profiled nmethods' 13952
>> ==> Metaspace 506696
>> ==> Compressed Class Space 43312
>> init = 7667712(7488K) used = 2096504(2047K) committed = 8454144(8256K) max =
>> -1(-1K)
>>
>> In this way, getNonHeapMemoryUsage is larger than it ought to be, it should
>> be `NonHeapUsage = CodeCache + Metaspace`.
>
> Yi Yang has updated the pull request incrementally with one additional commit
> since the last revision:
>
> address @tstuefe's comments; remove unnecessary declaration
I think @iklam meant something somewhat different. Since we remove the class
space bean, we now need to rewrite those tests using that bean.
Lets say we create the following whitebox APIs
- long WB_getClassSpaceUsage
- long WB_getClassSpaceCommitted
Maybe also (to be symmetric, and to not have to mix bean code and this code in
test/hotspot/jtreg/vmTestbase/metaspace/gc/MemoryUsageTest.java:
- long WB_getMetaSpaceUsage
- long WB_getMetaSpaceCommitted
Maybe also:
- boolean WB_usesClassSpace()
- long WB_classSpaceMax()
though these can easily be implemented using existing whitebox method (there is
one to get VM flags, so you could get `UseCompressedClassPointers` and
`CompressedClassSpaceSize` instead.
Now:
- In test/hotspot/jtreg/vmTestbase/metaspace/gc/MemoryUsageTest.java, you don't
use beans anymore but those functions. You'd rewrite "getUsed()" and
"getCommitted()" to use the new whitebox functions.
- In metaspce/ShrinkGrowTest, the bean is only used to confirm that class space
is active. You can use WB_usesClassSpace for that, or the value of
"UseCompressedClassPointers" flag.
- In
test/hotspot/jtreg/vmTestbase/vm/mlvm/indy/stress/gc/lotsOfCallSites/Test.java,
we use Compressed Class Bean to get Compressed Class usage and maximum size.
YHere, you would have to exchange `classMetadataPoolMXB.getUsage();` with
`WB_getClassSpaceUsage()` and `classMetadataPoolMXB.getUsage();` with
`CompressedClassSpaceSize`
----
Note that since this RFR really grew in complexity compared to what you wanted
to do originally, I'd be fine with dropping it altogether. If we continue, I
think above proposal is the simplest way to go.
src/hotspot/share/services/memoryPool.cpp line 188:
> 186:
> 187: // Note, any NonHeap pools would be counted into Non-Heap memory by
> MemoryMXBean.getNonHeapMemoryUsage.
> 188: // Make sure that it behaves as you expected if you want to add a new
> type of NonHeap pool
This comment is somewhat cryptic. Behave like what?
src/hotspot/share/services/memoryPool.cpp line 189:
> 187: // Note, any NonHeap pools would be counted into Non-Heap memory by
> MemoryMXBean.getNonHeapMemoryUsage.
> 188: // Make sure that it behaves as you expected if you want to add a new
> type of NonHeap pool
> 189: MetaspacePool::MetaspacePool() :
Can you please add a comment like
"Accounts for Metaspace (both class space and non-class space).
Max usage is MaxMetaspaceSize. Current usage includes prematurely freed blocks.
As far as this API is concerned, CompressedClassSpaceSize is ignored."
test/hotspot/jtreg/vmTestbase/nsk/share/gc/gp/GarbageUtils.java line 53:
> 51: ANY (),
> 52: HEAP("Java heap space"),
> 53: METASPACE("Metaspace");
This chance is wrong, I think. We still have class space OOMEs.
-------------
Changes requested by stuefe (Reviewer).
PR: https://git.openjdk.org/jdk/pull/8831
