Unexpected behavior for `KA.device!(backend, num)`

[simone-silvestri]

Over at Oceananingans, we had memory issues related to the fact that it seems that

KA.device!(backend, num)

does not switch to the intended device
MWE:

julia> using CUDA, KernelAbstractions

julia> KernelAbstractions.device!(CUDABackend(), 2)

julia> CUDA.device() # should be device number 1
CuDevice(0): NVIDIA TITAN V

This is because device! is only defined for an Int32
https://github.com/JuliaGPU/CUDA.jl/blob/cd2ab1d22e36396b6a1141ee8782d182a5020087/src/CUDAKernels.jl#L67-L69

julia> KernelAbstractions.device!(CUDABackend(), Int32(2))
CuDevice(1): NVIDIA TITAN V

Why is this the case? Should we allow any integer? Or maybe a non-silent failure in case the device cannot be switched

[vchuravy]

Off that's nasty.

KernelAbstractions.jl/src/KernelAbstractions.jl

Line 622 in 1ac546f

function device!(backend::Backend, id::Int)

So CUDAKernels also should have used Int

(Can you open a PR?)