diff options
| -rw-r--r-- | arch/powerpc/mm/pgtable_64.c | 7 | ||||
| -rw-r--r-- | include/linux/bug.h | 9 | ||||
| -rw-r--r-- | include/linux/huge_mm.h | 3 | ||||
| -rw-r--r-- | mm/huge_memory.c | 17 |
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); |