RFR: 8329469: Generational ZGC: Move the methods forwarding_[index|find|insert] from zRelocate.cpp to ZForwarding [v2]

[Guoxiong Li]

On Tue, 2 Apr 2024 11:03:38 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> Guoxiong Li has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
>> 
>>  - Mark several methods as private. Reduce cursor.
>>  - Merge branch 'master' into MOVE_FORWARDING
>>  - Move methods about ZForwarding.
>
> src/hotspot/share/gc/z/zForwarding.hpp line 153:
> 
>> 151:   zoffset insert(uintptr_t from_index, zoffset to_offset, ZForwardingCursor* cursor);
>> 152:   zaddress insert(zoffset from_offset, zaddress to_addr, ZForwardingCursor* cursor);
>> 153:   zaddress insert(zaddress from_addr, zaddress to_addr, ZForwardingCursor* cursor);
> 
> Could some of these functions be moved to the `private:` section where you added the `index` function?

I moved four methods.

> src/hotspot/share/gc/z/zRelocate.cpp line 356:
> 
>> 354: 
>> 355:   // Lookup forwarding
>> 356:   zaddress to_addr = forwarding->find(from_addr, &cursor);
> 
> While looking at this, I now see that this could use the find overload that doesn't take a ZForwardingCursor. Could you update the code to do so?

The `cursor` here can be used by the following `insert`. So it is good to keep it.

> src/hotspot/share/gc/z/zRelocate.cpp line 384:
> 
>> 382: zaddress ZRelocate::forward_object(ZForwarding* forwarding, zaddress_unsafe from_addr) {
>> 383:   ZForwardingCursor cursor;
>> 384:   const zaddress to_addr = forwarding->find(from_addr, &cursor);
> 
> Same here. The cursor is not necessary.

Removed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18579#discussion_r1547896619
PR Review Comment: https://git.openjdk.org/jdk/pull/18579#discussion_r1547896581
PR Review Comment: https://git.openjdk.org/jdk/pull/18579#discussion_r1547896527