RFR: 8340103: Add internal set_flag function to VMATree [v5]

[Afshin Zafari]

On Wed, 18 Sep 2024 09:23:39 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

>> Hi!
>> 
>> The old VirtualMemoryTracker has a method set_reserved_region_type(address, flag). We implement this for the new VMATree implementation by altering the signature slightly to set_reserved_region_type(address, size, flag). This simplifies the implementation greatly for our new data structure and leads to trivial changes for the callers (all callers already know the size).
>> 
>> This PR implements the internal implementation along with tests, but does not change any callers.
>> 
>> I also do a few cleanups:
>> 
>> - Change `Node` to `TreeNode` in tests, we've seen build failures because of this (probably a precompiled headers issue)
>> - Add a few `print_on` methods for  easy debugging
>> - Add a `size` alias, it was a bit confusing that some functions took an argument `position sz`, so changed that to `size sz` 
>> 
>> Thanks.
>
> Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Hopefully this is it

Thanks for the work. This enables the `MemTracker::record_virtual_memory_tag` to just use this API and apply the results.

Just a few cases of 'flag' is missed in comments or in assertion strings. There should be 'tag'.
Can we use `add(SummaryDiff& other)` instead of `apply(SummaryDiff& other)`?

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

PR Review: https://git.openjdk.org/jdk/pull/20994#pullrequestreview-2312277962