Hi, Nico Some nit below.
On Tue, Aug 19, 2025 at 07:41:55AM -0600, Nico Pache wrote: >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 <[email protected]> >Acked-by: David Hildenbrand <[email protected]> >Co-developed-by: Dev Jain <[email protected]> >Signed-off-by: Dev Jain <[email protected]> >Signed-off-by: Nico Pache <[email protected]> >--- > mm/khugepaged.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > >diff --git a/mm/khugepaged.c b/mm/khugepaged.c >index b7b98aebb670..2d192ec961d2 100644 >--- a/mm/khugepaged.c >+++ b/mm/khugepaged.c There is a comment above this function, which says "revalidate vma before taking mmap_lock". I am afraid it is "after taking mmap_lock"? or "after taking mmap_lock again"? >@@ -917,7 +917,7 @@ static int collapse_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; > enum tva_type type = cc->is_khugepaged ? TVA_KHUGEPAGED : >@@ -930,9 +930,10 @@ 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, type, PMD_ORDER)) >+ if (!thp_vma_allowable_orders(vma, vma->vm_flags, type, orders)) > return SCAN_VMA_CHECK; > /* > * Anon VMA expected, the address may be unmapped then Below is a comment, "thp_vma_allowable_order may return". Since you use thp_vma_allowable_orders, maybe we need to change the comment too. >@@ -1134,7 +1135,8 @@ 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; >@@ -1168,7 +1170,8 @@ 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 */ >@@ -2807,7 +2810,7 @@ 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; >-- >2.50.1 > -- Wei Yang Help you, Help me
