RFR: 8263131: reduce unnecessary downwards search when using linear search to find method

[Ioi Lam]

On Sat, 6 Mar 2021 14:38:03 GMT, Lehua Ding <github.com+13173904+lhtin at openjdk.org> wrote:

> Hi,
> 
> The `InstanceKlass::find_method_by_name` and `InstanceKlass::find_method_index` use `InstanceKlass::quick_search` to find a method by name. If the method found doesn't match the expected method signature, It has to search downwards and upwards. But if `_disable_method_binary_search` was set to `true`, the `InstanceKlass::quick_search` will use linear search instead of binary search to find the method. So there no needs to search downwards because there no other method with the same name before it since the method found is the first matched method.
> 
> Best regards,
> Lehua

_disable_method_binary_search is used only when dumping a CDS archive. Have you run all the test cases under test/hotspot/jtreg/runtime/cds?

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

PR: https://git.openjdk.java.net/jdk/pull/2857