Re: [PATCH v3 3/4] mm: Support batched unmap for lazyfree large folios during reclamation

On Wed, Feb 5, 2025 at 12:38 AM David Hildenbrand [off-list ref] wrote:

Hi,

quoted

      unsigned long hsz = 0;

@@ -1780,6 +1800,16 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
                              hugetlb_vma_unlock_write(vma);
                      }
                      pteval = huge_ptep_clear_flush(vma, address, pvmw.pte);
+             } else if (folio_test_large(folio) && !(flags & TTU_HWPOISON) &&
+                             can_batch_unmap_folio_ptes(address, folio, pvmw.pte)) {
+                     nr_pages = folio_nr_pages(folio);
+                     flush_cache_range(vma, range.start, range.end);
+                     pteval = get_and_clear_full_ptes(mm, address, pvmw.pte, nr_pages, 0);
+                     if (should_defer_flush(mm, flags))
+                             set_tlb_ubc_flush_pending(mm, pteval, address,
+                                     address + folio_size(folio));
+                     else
+                             flush_tlb_range(vma, range.start, range.end);
              } else {

I have some fixes [1] that will collide with this series. I'm currently
preparing a v2, and am not 100% sure when the fixes will get queued+merged.

I'll base them against mm-stable for now, and send them out based on
that, to avoid the conflicts here (should all be fairly easy to resolve
from a quick glimpse).

So we might have to refresh this series here if the fixes go in first.

I assume you're referring to "[PATCH v1 08/12] mm/rmap: handle
device-exclusive entries correctly in try_to_unmap_one()". It looks
straightforward to resolve the conflict. If your patch is applied first,
I'll send a rebase.

[1] https://lkml.kernel.org/r/20250129115411.2077152-1-david@redhat.com

--
Cheers,

David / dhildenb

Thanks
Barry