RFR: 8266642: improve ResolvedMethodTable hash function [v7]

[Vladimir Ivanov]

On Fri, 14 May 2021 12:04:55 GMT, Denghui Dong <ddong at openjdk.org> wrote:

>> JDK-8249719 has fixed the bad hash function problem, however, the performance problem still exists when there are a large number of classes with the same name.
>> Adding the address of the corresponding ClassLoaderData as a factor of hash can solve the problem.
>
> Denghui Dong has updated the pull request incrementally with one additional commit since the last revision:
> 
>   refactor

Looks good to me, but, please, wait for somebody from Runtime team to approve it.

src/hotspot/share/prims/resolvedMethodTable.cpp line 56:

> 54: 
> 55: unsigned int method_hash(const Method* method) {
> 56:   unsigned int hash = method->method_holder()->class_loader_data()->identity_hash();

I don't see "#include classfile/classLoaderData.hpp" in your patch. Did you verify it builds successfully? I saw a compilation failure without the include:


src/hotspot/share/prims/resolvedMethodTable.cpp:56:67: error: member access into incomplete type 'ClassLoaderData'
  unsigned int hash = method->method_holder()->class_loader_data()->identity_hash();
                                                                  ^
src/hotspot/share/memory/allocation.hpp:260:7: note: forward declaration of 'ClassLoaderData'
class ClassLoaderData;
      ^
1 error generated.

-------------

Marked as reviewed by vlivanov (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/3901