Re: [PATCH v2 2/3] resource: Add release_mem_region_adjustable()

From: David Rientjes
Date: Wed Apr 10 2013 - 02:16:32 EST


On Mon, 8 Apr 2013, Toshi Kani wrote:

> Added release_mem_region_adjustable(), which releases a requested
> region from a currently busy memory resource. This interface
> adjusts the matched memory resource accordingly even if the
> requested region does not match exactly but still fits into.
>
> This new interface is intended for memory hot-delete. During
> bootup, memory resources are inserted from the boot descriptor
> table, such as EFI Memory Table and e820. Each memory resource
> entry usually covers the whole contigous memory range. Memory
> hot-delete request, on the other hand, may target to a particular
> range of memory resource, and its size can be much smaller than
> the whole contiguous memory. Since the existing release interfaces
> like __release_region() require a requested region to be exactly
> matched to a resource entry, they do not allow a partial resource
> to be released.
>
> There is no change to the existing interfaces since their restriction
> is valid for I/O resources.
>
> Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>

Should this emit a warning for attempting to free a non-existant region
like __release_region() does?

I think it would be better to base this off my patch and surround it with
#ifdef CONFIG_MEMORY_HOTREMOVE as suggested by Andrew. There shouldn't be
any conflicts.
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