Re: Swap Min Odrer

[David Hildenbrand <david@redhat.com>]

On 07.01.25 10:43, Daniel Gomez wrote:
> Hi,

Hi,

> 
> High-capacity SSDs require writes to be aligned with the drive's
> indirection unit (IU), which is typically >4 KiB, to avoid RMW. To
> support swap on these devices, we need to ensure that writes do not
> cross IU boundaries. So, I think this may require increasing the minimum
> allocation size for swap users.

How would we handle swapout/swapin when we have smaller pages (just 
imagine someone does a mmap(4KiB))?

Could this be something that gets abstracted/handled by the swap 
implementation? (i.e., multiple small folios get added to the swapcache 
but get written out / read in as a single unit?).

I recall that we have been talking about a better swap abstraction for 
years :)

Might be a good topic for LSF/MM (might or might not be a better place 
than the MM alignment session).

-- 
Cheers,

David / dhildenb