diff options
| author | Dev Jain <dev.jain@arm.com> | 2025-07-24 10:53:00 +0530 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-08-02 12:06:10 -0700 |
| commit | 4ea3594a47412f9dd20fbda0dc70b0cbec9cba43 (patch) | |
| tree | fb3fb9cf6ef0484675f4ce7e755743ff62477df5 | |
| parent | 3dfde97800e06882960cc926d2c428f2128b7c70 (diff) | |
khugepaged: optimize __collapse_huge_page_copy_succeeded() by PTE batching
Use PTE batching to batch process PTEs mapping the same large folio. An
improvement is expected due to batching refcount-mapcount manipulation on
the folios, and for arm64 which supports contig mappings, the number of
TLB flushes is also reduced.
Link: https://lkml.kernel.org/r/20250724052301.23844-3-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/khugepaged.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index a55fb1dcd224..f23e943506bc 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -700,12 +700,15 @@ static void __collapse_huge_page_copy_succeeded(pte_t *pte, spinlock_t *ptl, struct list_head *compound_pagelist) { + unsigned long end = address + HPAGE_PMD_SIZE; struct folio *src, *tmp; - pte_t *_pte; pte_t pteval; + pte_t *_pte; + unsigned int nr_ptes; - for (_pte = pte; _pte < pte + HPAGE_PMD_NR; - _pte++, address += PAGE_SIZE) { + for (_pte = pte; _pte < pte + HPAGE_PMD_NR; _pte += nr_ptes, + address += nr_ptes * PAGE_SIZE) { + nr_ptes = 1; pteval = ptep_get(_pte); if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); @@ -722,18 +725,26 @@ static void __collapse_huge_page_copy_succeeded(pte_t *pte, struct page *src_page = pte_page(pteval); src = page_folio(src_page); - if (!folio_test_large(src)) + + if (folio_test_large(src)) { + unsigned int max_nr_ptes = (end - address) >> PAGE_SHIFT; + + nr_ptes = folio_pte_batch(src, _pte, pteval, max_nr_ptes); + } else { release_pte_folio(src); + } + /* * ptl mostly unnecessary, but preempt has to * be disabled to update the per-cpu stats * inside folio_remove_rmap_pte(). */ spin_lock(ptl); - ptep_clear(vma->vm_mm, address, _pte); - folio_remove_rmap_pte(src, src_page, vma); + clear_ptes(vma->vm_mm, address, _pte, nr_ptes); + folio_remove_rmap_ptes(src, src_page, nr_ptes, vma); spin_unlock(ptl); - free_folio_and_swap_cache(src); + free_swap_cache(src); + folio_put_refs(src, nr_ptes); } } |