Re: [PATCH v6 1/3] memory: implement memory_block_advise/probe_max_size

[Dan Williams]

Gregory Price wrote:
> Hotplug memory sources may have opinions on what the memblock size
> should be - usually for alignment purposes.  For example, CXL memory
> extents can be 256MB with a matching alignment. If this size/alignment
> is smaller than the block size, it can result in stranded capacity.
> 
> Implement memory_block_advise_max_size for use prior to allocator init,
> for software to advise the system on the max block size.
> 
> Implement memory_block_probe_max_size for use by arch init code to
> calculate the best block size. Use of advice is architecture defined.
> 
> The probe value can never change after first probe. Calls to advise
> after probe will return -EBUSY to aid debugging.
> 
> On systems without hotplug, always return -ENODEV and 0 respectively.

Should the advice just succeed when the result does not matter?

Otherwise, it depends on the caller to not care based on config.

I do not feel that strongly about it, so either way:

Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx>