mm/mlock: implement folio_mlock_step() using folio_pte_batch()

Let's make folio_mlock_step() simply a wrapper around folio_pte_batch(),
which will greatly reduce the cost of ptep_get() when scanning a range of
contptes.

Link: https://lkml.kernel.org/r/20240611010418.70797-1-ioworker0@gmail.com
Signed-off-by: Lance Yang <ioworker0@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Suggested-by: Barry Song <21cnbao@gmail.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Cc: Bang Li <libang.li@antgroup.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/mlock.c b/mm/mlock.c
index 30b51cdea89decc236249867bd984475e75d58e2..52d6e401ad6764fb5b3e455b03cc793ef53d5f6c 100644 (file)
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -307,26 +307,15 @@ void munlock_folio(struct folio *folio)
 static inline unsigned int folio_mlock_step(struct folio *folio,
                pte_t *pte, unsigned long addr, unsigned long end)
 {
-       unsigned int count, i, nr = folio_nr_pages(folio);
-       unsigned long pfn = folio_pfn(folio);
+       const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
+       unsigned int count = (end - addr) >> PAGE_SHIFT;
        pte_t ptent = ptep_get(pte);
 
        if (!folio_test_large(folio))
                return 1;
 
-       count = pfn + nr - pte_pfn(ptent);
-       count = min_t(unsigned int, count, (end - addr) >> PAGE_SHIFT);
-
-       for (i = 0; i < count; i++, pte++) {
-               pte_t entry = ptep_get(pte);
-
-               if (!pte_present(entry))
-                       break;
-               if (pte_pfn(entry) - pfn >= nr)
-                       break;
-       }
-
-       return i;
+       return folio_pte_batch(folio, addr, pte, ptent, count, fpb_flags, NULL,
+                              NULL, NULL);
 }
 
 static inline bool allow_mlock_munlock(struct folio *folio,