[PATCH v8 03/15] khugepaged: generalize hugepage_vma_revalidate for mTHP support
From: Nico Pache <npache@redhat.com>
Date: 2025-07-02 05:59:24
Also in:
linux-doc, linux-mm, lkml
Subsystem:
memory management, memory management - thp (transparent huge page), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Linus Torvalds
For khugepaged to support different mTHP orders, we must generalize this to check if the PMD is not shared by another VMA and the order is enabled. To ensure madvise_collapse can support working on mTHP orders without the PMD order enabled, we need to convert hugepage_vma_revalidate to take a bitmap of orders. No functional change in this patch. Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Co-developed-by: Dev Jain <dev.jain@arm.com> Signed-off-by: Dev Jain <dev.jain@arm.com> Signed-off-by: Nico Pache <npache@redhat.com> --- mm/khugepaged.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index bf69e81a3d82..7bcd4d280c71 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c@@ -907,7 +907,7 @@ static int khugepaged_find_target_node(struct collapse_control *cc) static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, bool expect_anon, struct vm_area_struct **vmap, - struct collapse_control *cc) + struct collapse_control *cc, unsigned long orders) { struct vm_area_struct *vma; unsigned long tva_flags = cc->is_khugepaged ? TVA_ENFORCE_SYSFS : 0;
@@ -919,9 +919,10 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, if (!vma) return SCAN_VMA_NULL; + /* Always check the PMD order to insure its not shared by another VMA */ if (!thp_vma_suitable_order(vma, address, PMD_ORDER)) return SCAN_ADDRESS_RANGE; - if (!thp_vma_allowable_order(vma, vma->vm_flags, tva_flags, PMD_ORDER)) + if (!thp_vma_allowable_orders(vma, vma->vm_flags, tva_flags, orders)) return SCAN_VMA_CHECK; /* * Anon VMA expected, the address may be unmapped then
@@ -1115,7 +1116,8 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, goto out_nolock; mmap_read_lock(mm); - result = hugepage_vma_revalidate(mm, address, true, &vma, cc); + result = hugepage_vma_revalidate(mm, address, true, &vma, cc, + BIT(HPAGE_PMD_ORDER)); if (result != SCAN_SUCCEED) { mmap_read_unlock(mm); goto out_nolock;
@@ -1149,7 +1151,8 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, * mmap_lock. */ mmap_write_lock(mm); - result = hugepage_vma_revalidate(mm, address, true, &vma, cc); + result = hugepage_vma_revalidate(mm, address, true, &vma, cc, + BIT(HPAGE_PMD_ORDER)); if (result != SCAN_SUCCEED) goto out_up_write; /* check if the pmd is still valid */
@@ -2780,7 +2783,7 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start, mmap_read_lock(mm); mmap_locked = true; result = hugepage_vma_revalidate(mm, addr, false, &vma, - cc); + cc, BIT(HPAGE_PMD_ORDER)); if (result != SCAN_SUCCEED) { last_fail = result; goto out_nolock;
--
2.49.0