On 10.07.24 05:34, Jason A. Donenfeld wrote:
On Wed, Jul 10, 2024 at 05:05:06AM +0200, David Hildenbrand wrote:
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.
Right, no swap, as boring a system as can be. I've experimented with
that behavior on my swap-less 64GB thinkpad, as well as on little
special purpose VMs, where I hacked the VM_DROPPABLE test code into the
wireguard test suite.
Great, thanks!
--
Cheers,
David / dhildenb
