Re: [PATCH v13 mm-new 05/16] khugepaged: introduce is_mthp_order helper
From: Zi Yan <ziy@nvidia.com>
Date: 2025-12-03 03:13:44
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On 1 Dec 2025, at 12:46, Nico Pache wrote:
quoted hunk ↗ jump to hunk
In order to add mTHP support, we will often be checking if a given order is a mTHP or PMD order. Lets create a simple helper function to keep the code clean and readable. Suggested-by: Lorenzo Stoakes <redacted> Signed-off-by: Nico Pache <npache@redhat.com> --- mm/khugepaged.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 8599c7fa112e..9c041141b2e3 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c@@ -338,6 +338,11 @@ static bool pte_none_or_zero(pte_t pte) return pte_present(pte) && is_zero_pfn(pte_pfn(pte)); } +static bool is_mthp_order(unsigned int order) +{ + return order != HPAGE_PMD_ORDER; +} +
The code at the bottom of __folio_split() in mm/huge_memory.c can use this helper. The code in deferred_split_folio() uses folio_test_pmd_mappable() instead of order == HPAGE_PMD_ORDER, but the code can be changed to use the helper.
quoted hunk ↗ jump to hunk
int hugepage_madvise(struct vm_area_struct *vma, vm_flags_t *vm_flags, int advice) {@@ -1071,13 +1076,13 @@ static int alloc_charge_folio(struct folio **foliop, struct mm_struct *mm, folio = __folio_alloc(gfp, order, node, &cc->alloc_nmask); if (!folio) { *foliop = NULL; - if (order == HPAGE_PMD_ORDER) + if (!is_mthp_order(order)) count_vm_event(THP_COLLAPSE_ALLOC_FAILED); count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC_FAILED); return SCAN_ALLOC_HUGE_PAGE_FAIL; } - if (order == HPAGE_PMD_ORDER) + if (!is_mthp_order(order)) count_vm_event(THP_COLLAPSE_ALLOC); count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC);-- 2.51.1
Best Regards, Yan, Zi