Re: [PATCH 2/2] ksm: Optimize rmap_walk_ksm by passing a suitable address range

[yang.yang29]

> + pgoff_start = rmap_item->address >> PAGE_SHIFT;
> + pgoff_end = pgoff_start + folio_nr_pages(folio) - 1;
> +
> anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root,
> - 0, ULONG_MAX) {
> + pgoff_start, pgoff_end) {

Good job.
I see there is another similar situations in collect_procs_ksm().
We can simulate memory errors by calling the memory_failure().