Re: [PATCH v21 1/4] mm: add VM_DROPPABLE for designating always lazily freeable mappings

[David Hildenbrand]

On 09.07.24 04:17, Jason A. Donenfeld wrote:
> Hi David,
>
> On Mon, Jul 08, 2024 at 10:21:09PM +0200, David Hildenbrand wrote:
> > BTW, I was just trying to understand how MADV_FREE + MAP_DROPPABLE would
> > behave without any swap space around.
> >
> > Did you experiment with that?
>
> You mean on a system without any swap configured? That's actually my
> primary test environment for this. It behaves as expected: when ram
> fills up and the scanner is trying to reclaim what it can,
> folio_test_swapbacked(folio) is false, and the memory gets freed. After,
> reads fault in a zero page. So it's working as expected.

Okay, just to be clear: no swap/zram/zswap. The reclaim code regarding 
not scanning anonymous memory without swap was a bit confusing.

thanks!

--
Cheers,

David / dhildenb