Re: [PATCH v12 02/11] mm, swap: Add infrastructure for saving page metadata on swap

[Dave Hansen]

On 02/21/2018 09:15 AM, Khalid Aziz wrote:
> If a processor supports special metadata for a page, for example ADI
> version tags on SPARC M7, this metadata must be saved when the page is
> swapped out. The same metadata must be restored when the page is swapped
> back in. This patch adds two new architecture specific functions -
> arch_do_swap_page() to be called when a page is swapped in, and
> arch_unmap_one() to be called when a page is being unmapped for swap
> out. These architecture hooks allow page metadata to be saved if the
> architecture supports it.

I still think silently squishing cacheline-level hardware data into
page-level software data structures is dangerous.

But, you seem rather determined to do it this way.  I don't think this
will _hurt_ anyone else, though other than needlessly cluttering up the
code.