On Mon, Feb 08, 2016 at 12:11:00PM +0530, Aneesh Kumar K.V wrote: > With next generation power processor, we are having a new mmu model > [1] that require us to maintain a different linux page table format. > > Inorder to support both current and future ppc64 systems with a single > kernel we need to make sure kernel can select between different page > table format at runtime. With the new MMU (radix MMU) added, we will > have two different pmd hugepage size 16MB for hash model and 2MB for > Radix model. Hence make HPAGE_PMD related values as a variable. > > [1] http://ibm.biz/power-isa3 (Needs registration). > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> > --- > arch/arm/include/asm/pgtable-3level.h | 8 ++++++++ > arch/arm64/include/asm/pgtable.h | 7 +++++++ > arch/mips/include/asm/pgtable.h | 8 ++++++++ > arch/powerpc/mm/pgtable_64.c | 7 +++++++ > arch/s390/include/asm/pgtable.h | 8 ++++++++ > arch/sparc/include/asm/pgtable_64.h | 7 +++++++ > arch/tile/include/asm/pgtable.h | 9 +++++++++ > arch/x86/include/asm/pgtable.h | 8 ++++++++ > include/linux/huge_mm.h | 3 --- > mm/huge_memory.c | 8 +++++--- > 10 files changed, 67 insertions(+), 6 deletions(-) That is ugly. What about this: 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 08fc0ba2207e..bc33330b5547 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); @@ -650,16 +650,36 @@ static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) } #endif /* CONFIG_SYSFS */ +#define MAYBE_BUILD_BUG_ON(cond) \ +({ \ + if (__builtin_constant_p((cond))) \ + BUILD_BUG_ON(cond); \ + else \ + BUG_ON(cond); \ +}) + 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; + if (!has_transparent_hugepage()) { transparent_hugepage_flags = 0; return -EINVAL; } + /* 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; @@ -760,12 +780,6 @@ static inline struct list_head *page_deferred_list(struct page *page) 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); } -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>