@@ -281,6 +281,14 @@ static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 	flush_pmd_entry(pmdp);
 }
 
+#if HPAGE_PMD_ORDER >= MAX_ORDER
+#error "hugepages can't be allocated by the buddy allocator"
+#endif
+
+#if HPAGE_PMD_ORDER < 2
+#error "We need more than 2 pages to do deferred thp split"
+#endif
+
 static inline int has_transparent_hugepage(void)
 {
 	return 1;

@@ -379,6 +379,13 @@ static inline pgprot_t mk_sect_prot(pgprot_t prot)
 
 #define set_pmd_at(mm, addr, pmdp, pmd)	set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
 
+#if HPAGE_PMD_ORDER >= MAX_ORDER
+#error "hugepages can't be allocated by the buddy allocator"
+#endif
+
+#if HPAGE_PMD_ORDER < 2
+#error "We need more than 2 pages to do deferred thp split"
+#endif
 static inline int has_transparent_hugepage(void)
 {
 	return 1;

@@ -468,6 +468,14 @@ static inline int io_remap_pfn_range(struct vm_area_struct *vma,
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 
+#if HPAGE_PMD_ORDER >= MAX_ORDER
+#error "hugepages can't be allocated by the buddy allocator"
+#endif
+
+#if HPAGE_PMD_ORDER < 2
+#error "We need more than 2 pages to do deferred thp split"
+#endif
+
 extern int has_transparent_hugepage(void);
 
 static inline int pmd_trans_huge(pmd_t pmd)

@@ -785,6 +785,13 @@ pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 
 int has_transparent_hugepage(void)
 {
+
+	BUILD_BUG_ON_MSG((PMD_SHIFT - PAGE_SHIFT) >= MAX_ORDER,
+		"hugepages can't be allocated by the buddy allocator");
+
+	BUILD_BUG_ON_MSG((PMD_SHIFT - PAGE_SHIFT) < 2,
+			 "We need more than 2 pages to do deferred thp split");
+
 	if (!mmu_has_feature(MMU_FTR_16M_PAGE))
 		return 0;
 	/*

@@ -1617,6 +1617,14 @@ static inline int pmd_trans_huge(pmd_t pmd)
 	return pmd_val(pmd) & _SEGMENT_ENTRY_LARGE;
 }
 
+#if HPAGE_PMD_ORDER >= MAX_ORDER
+#error "hugepages can't be allocated by the buddy allocator"
+#endif
+
+#if HPAGE_PMD_ORDER < 2
+#error "We need more than 2 pages to do deferred thp split"
+#endif
+
 static inline int has_transparent_hugepage(void)
 {
 	return MACHINE_HAS_HPAGE ? 1 : 0;

@@ -683,6 +683,13 @@ static inline unsigned long pmd_trans_huge(pmd_t pmd)
 	return pte_val(pte) & _PAGE_PMD_HUGE;
 }
 
+#if HPAGE_PMD_ORDER >= MAX_ORDER
+#error "hugepages can't be allocated by the buddy allocator"
+#endif
+
+#if HPAGE_PMD_ORDER < 2
+#error "We need more than 2 pages to do deferred thp split"
+#endif
 #define has_transparent_hugepage() 1
 
 static inline pmd_t pmd_mkold(pmd_t pmd)

@@ -488,6 +488,15 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
+#if HPAGE_PMD_ORDER >= MAX_ORDER
+#error "hugepages can't be allocated by the buddy allocator"
+#endif
+
+#if HPAGE_PMD_ORDER < 2
+#error "We need more than 2 pages to do deferred thp split"
+#endif
+
 #define has_transparent_hugepage() 1
 #define pmd_trans_huge pmd_huge_page
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */

@@ -173,6 +173,13 @@ static inline int pmd_devmap(pmd_t pmd)
 	return !!(pmd_val(pmd) & _PAGE_DEVMAP);
 }
 
+#if HPAGE_PMD_ORDER >= MAX_ORDER
+#error "hugepages can't be allocated by the buddy allocator"
+#endif
+
+#if HPAGE_PMD_ORDER < 2
+#error "We need more than 2 pages to do deferred thp split"
+#endif
 static inline int has_transparent_hugepage(void)
 {
 	return cpu_has_pse;

@@ -111,9 +111,6 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 			__split_huge_pmd(__vma, __pmd, __address);	\
 	}  while (0)
 
-#if HPAGE_PMD_ORDER >= MAX_ORDER
-#error "hugepages can't be allocated by the buddy allocator"
-#endif
 extern int hugepage_madvise(struct vm_area_struct *vma,
 			    unsigned long *vm_flags, int advice);
 extern void vma_adjust_trans_huge(struct vm_area_struct *vma,

@@ -81,7 +81,7 @@ unsigned long transparent_hugepage_flags __read_mostly =
 	(1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
 
 /* default scan 8*512 pte (or vmas) every 30 second */
-static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8;
+static unsigned int khugepaged_pages_to_scan __read_mostly;
 static unsigned int khugepaged_pages_collapsed;
 static unsigned int khugepaged_full_scans;
 static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000;

@@ -96,8 +96,8 @@ static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
  * it would have happened if the vma was large enough during page
  * fault.
  */
-static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1;
-static unsigned int khugepaged_max_ptes_swap __read_mostly = HPAGE_PMD_NR/8;
+static unsigned int khugepaged_max_ptes_none __read_mostly;
+static unsigned int khugepaged_max_ptes_swap __read_mostly;
 
 static int khugepaged(void *none);
 static int khugepaged_slab_init(void);

@@ -685,6 +685,10 @@ static int __init hugepage_init(void)
 	int err;
 	struct kobject *hugepage_kobj;
 
+	khugepaged_pages_to_scan = HPAGE_PMD_NR*8;
+	khugepaged_max_ptes_none = HPAGE_PMD_NR-1;
+	khugepaged_max_ptes_swap = HPAGE_PMD_NR/8;
+
 	if (!has_transparent_hugepage()) {
 		transparent_hugepage_flags = 0;
 		return -EINVAL;

@@ -794,7 +798,6 @@ void prep_transhuge_page(struct page *page)
 	 * we use page->mapping and page->indexlru in second tail page
 	 * as list_head: assuming THP order >= 2
 	 */
-	BUILD_BUG_ON(HPAGE_PMD_ORDER < 2);
 
 	INIT_LIST_HEAD(page_deferred_list(page));
 	set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR);