On 11.12.23 17:33, Matthew Wilcox wrote:
On Mon, Dec 11, 2023 at 04:56:15PM +0100, David Hildenbrand wrote:
hugetlb rmap handling differs quite a lot from "ordinary" rmap code.
For example, hugetlb currently only supports entire mappings, and treats
any mapping as mapped using a single "logical PTE". Let's move it out
of the way so we can overhaul our "ordinary" rmap.
implementation/interface.
Let's introduce and use hugetlb_remove_rmap() and remove the hugetlb
code from page_remove_rmap(). This effectively removes one check on the
small-folio path as well.
Note: all possible candidates that need care are page_remove_rmap() that
pass compound=true.
Reviewed-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
+++ b/mm/rmap.c
@@ -1482,13 +1482,6 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma,
VM_BUG_ON_PAGE(compound && !PageHead(page), page);
- /* Hugetlb pages are not counted in NR_*MAPPED */
- if (unlikely(folio_test_hugetlb(folio))) {
- /* hugetlb pages are always mapped with pmds */
- atomic_dec(&folio->_entire_mapcount);
- return;
- }
Maybe add
VM_BUG_ON_FOLIO(folio_test_hugetlb(folio), folio);
A bulk-add that in patch #6.
Thanks!
--
Cheers,
David / dhildenb
