If PMD-sized pages are not supported on an architecture (ie. the arch implements arch_has_pmd_leaves() and it returns false) then the current code disables all THP, including mTHP. This commit fixes this by allowing mTHP to be always enabled for all archs. When PMD-sized pages are not supported, its sysfs entry won't be created and their mapping will be disallowed at page-fault time. Signed-off-by: Luiz Capitulino --- mm/huge_memory.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1e5ea2e47f79..882331592928 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -115,6 +115,9 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma, else supported_orders = THP_ORDERS_ALL_FILE_DEFAULT; + if (!pgtable_has_pmd_leaves()) + supported_orders &= ~(BIT(PMD_ORDER) | BIT(PUD_ORDER)); + orders &= supported_orders; if (!orders) return 0; @@ -122,7 +125,7 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma, if (!vma->vm_mm) /* vdso */ return 0; - if (!pgtable_has_pmd_leaves() || vma_thp_disabled(vma, vm_flags, forced_collapse)) + if (vma_thp_disabled(vma, vm_flags, forced_collapse)) return 0; /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ @@ -806,6 +809,9 @@ static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) } orders = THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DEFAULT; + if (!pgtable_has_pmd_leaves()) + orders &= ~(BIT(PMD_ORDER) | BIT(PUD_ORDER)); + order = highest_order(orders); while (orders) { thpsize = thpsize_create(order, *hugepage_kobj); @@ -905,9 +911,6 @@ static int __init hugepage_init(void) int err; struct kobject *hugepage_kobj; - if (!pgtable_has_pmd_leaves()) - return -EINVAL; - /* * hugepages can't be allocated by the buddy allocator */ -- 2.52.0