Re: [PATCH] selftests/mm: uffd-missing-wp: add GC related functionality test

[Andrew Morton]

On Sun, 27 Sep 2026 23:26:31 -0400 Martin Cracauer <cracauer@xxxxxxxx> wrote:

> Add a test that asserts that functionality needed for generational
> garbage collection works.  Namely to implement a write barrier using
> userfaultfd instead of using segmentation faults.  The planned target
> is the GC in SBCL.
> 
> The real GC will initially fill heap pages by using on-demand loading
> of pages from an image file, either via mmap(2) or using userfaultfd
> to decompress a page read from an image file made from individually
> compressed blocks.  This test doesn't do that so that it needs no disk
> I/O and no decompression library.  Instead, a fault will be filled by
> copying page content from prepared pages in the heap.

Thanks.  Sashiko asked a couple of things:
	https://sashiko.dev/#/patchset/arneZ-KkRWUNI0Ho@xxxxxxxx