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-rw-r--r--arch/powerpc/mm/pgtable_64.c7
-rw-r--r--include/linux/bug.h9
-rw-r--r--include/linux/huge_mm.h3
-rw-r--r--mm/huge_memory.c17
4 files changed, 30 insertions, 6 deletions
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index af304e6d5a89..0eb53128ca2a 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -817,6 +817,13 @@ 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;
/*
diff --git a/include/linux/bug.h b/include/linux/bug.h
index 7f4818673c41..e51b0709e78d 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -20,6 +20,7 @@ struct pt_regs;
#define BUILD_BUG_ON_MSG(cond, msg) (0)
#define BUILD_BUG_ON(condition) (0)
#define BUILD_BUG() (0)
+#define MAYBE_BUILD_BUG_ON(cond) (0)
#else /* __CHECKER__ */
/* Force a compilation error if a constant expression is not a power of 2 */
@@ -83,6 +84,14 @@ struct pt_regs;
*/
#define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
+#define MAYBE_BUILD_BUG_ON(cond) \
+ do { \
+ if (__builtin_constant_p((cond))) \
+ BUILD_BUG_ON(cond); \
+ else \
+ BUG_ON(cond); \
+ } while (0)
+
#endif /* __CHECKER__ */
#ifdef CONFIG_GENERIC_BUG
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 459fd25b378e..f12513a20a06 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -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,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index aea8f7a42df9..36c22a89df61 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -83,7 +83,7 @@ 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;
@@ -98,7 +98,7 @@ 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_none __read_mostly;
static int khugepaged(void *none);
static int khugepaged_slab_init(void);
@@ -660,6 +660,18 @@ static int __init hugepage_init(void)
return -EINVAL;
}
+ khugepaged_pages_to_scan = HPAGE_PMD_NR * 8;
+ khugepaged_max_ptes_none = HPAGE_PMD_NR - 1;
+ /*
+ * hugepages can't be allocated by the buddy allocator
+ */
+ MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER);
+ /*
+ * we use page->mapping and page->index in second tail page
+ * as list_head: assuming THP order >= 2
+ */
+ MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2);
+
err = hugepage_init_sysfs(&hugepage_kobj);
if (err)
goto err_sysfs;
@@ -764,7 +776,6 @@ 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);