RFR: 8344882: (bf) Temporary direct buffers should not count against the upper limit on direct buffer memory

[Alan Bateman]

On Fri, 22 Nov 2024 23:44:11 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

> Make the memory used by internal temporary direct buffers not count towards the upper limit on direct buffer memory.

While you are there, can you also look into not creating a Cleaner for the temporary direct buffers? They are explicitly deallocated when they can't be returned to the TL cache or when the thread terminates (there is a hook in thread exit for this).

Also, on the surface it might look we could use a thread confined Arena and allocate MemorySegments and get a BB view but these temporary buffers are actually carrier local when there are virtual threads mounted.

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PR Comment: https://git.openjdk.org/jdk/pull/22339#issuecomment-2495590190