Ability to use temporary memory resource sets within ManagedArrays

[rcarson3]

@davidbeckingsale so for a library that I work on here at LLNL, I've been recently been looking at integrating CARE into it in-order to help simplify our internal memory management and our forall type kernels with the ever increasing need to support more and more hardware. I've been in talks with @adayton1 a bit about this, and he's been super helpful.

During some of our more recent discussions, I asked about how to make sure CARE uses the resource sets that an application code has told our library to use, so these would usually be resource sets associated with temporary memory. He pointed me to https://github.com/LLNL/CARE/blob/develop/src/care/care.cpp#L22, but warned me that this would change the global allocators that CHAI is using. I of course would rather avoid doing that for obvious reasons, and so @adayton1 mentioned there might be a way within CHAI to have a ManagedArray constructor take in a list of allocators which should allow me to make use of these temporary memory resource sets. Therefore, I figured it'd be a good idea to just open an issue and see if you had an advice/ideas for how best to handle this sort of use case of CHAI which could then be propagated up into CARE's use of ManagedArrays/host_device_ptrs.

[davidbeckingsale]

Would this constructor work for you: https://github.com/LLNL/CHAI/blob/develop/src/chai/ManagedArray.hpp#L101 ?

See here for an example: https://github.com/LLNL/CHAI/blob/develop/examples/chai-umpire-allocators.cpp

[rcarson3]

I believe that should work :) I should be able to use that method along with https://github.com/LLNL/CARE/blob/develop/src/care/host_device_ptr.h#L119 to at least initially prototype around with things.

[davidbeckingsale]

Great! Let us know if you have any questions.

[rcarson3]

I definitely will, and I'll reopen this issue if I do.