From: Matthew Wilcox <[email protected]> Add a vma_is_dax() helper macro to test whether the VMA is DAX, and use it in zap_huge_pmd() and __split_huge_page_pmd().
Signed-off-by: Matthew Wilcox <[email protected]> --- include/linux/dax.h | 4 ++++ mm/huge_memory.c | 46 ++++++++++++++++++++++++++++------------------ 2 files changed, 32 insertions(+), 18 deletions(-) diff --git a/include/linux/dax.h b/include/linux/dax.h index 4f27d3d..9b51f9d 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -18,4 +18,8 @@ int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *); #define dax_mkwrite(vma, vmf, gb, iod) dax_fault(vma, vmf, gb, iod) #define __dax_mkwrite(vma, vmf, gb, iod) __dax_fault(vma, vmf, gb, iod) +static inline bool vma_is_dax(struct vm_area_struct *vma) +{ + return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host); +} #endif diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 911071b..b7bd855 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -23,6 +23,7 @@ #include <linux/pagemap.h> #include <linux/migrate.h> #include <linux/hashtable.h> +#include <linux/dax.h> #include <asm/tlb.h> #include <asm/pgalloc.h> @@ -1391,7 +1392,6 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, int ret = 0; if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { - struct page *page; pgtable_t pgtable; pmd_t orig_pmd; /* @@ -1403,13 +1403,22 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, tlb->fullmm); tlb_remove_pmd_tlb_entry(tlb, pmd, addr); - pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); + if (vma_is_dax(vma)) { + if (is_huge_zero_pmd(orig_pmd)) { + pgtable = NULL; + } else { + spin_unlock(ptl); + return 1; + } + } else { + pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); + } if (is_huge_zero_pmd(orig_pmd)) { atomic_long_dec(&tlb->mm->nr_ptes); spin_unlock(ptl); put_huge_zero_page(); } else { - page = pmd_page(orig_pmd); + struct page *page = pmd_page(orig_pmd); page_remove_rmap(page); VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); @@ -1418,7 +1427,8 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, spin_unlock(ptl); tlb_remove_page(tlb, page); } - pte_free(tlb->mm, pgtable); + if (pgtable) + pte_free(tlb->mm, pgtable); ret = 1; } return ret; @@ -2887,7 +2897,7 @@ void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, pmd_t *pmd) { spinlock_t *ptl; - struct page *page; + struct page *page = NULL; struct mm_struct *mm = vma->vm_mm; unsigned long haddr = address & HPAGE_PMD_MASK; unsigned long mmun_start; /* For mmu_notifiers */ @@ -2900,25 +2910,25 @@ void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, again: mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); ptl = pmd_lock(mm, pmd); - if (unlikely(!pmd_trans_huge(*pmd))) { - spin_unlock(ptl); - mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); - return; - } - if (is_huge_zero_pmd(*pmd)) { + if (unlikely(!pmd_trans_huge(*pmd))) + goto unlock; + if (vma_is_dax(vma)) { + pmdp_huge_clear_flush(vma, haddr, pmd); + } else if (is_huge_zero_pmd(*pmd)) { __split_huge_zero_page_pmd(vma, haddr, pmd); - spin_unlock(ptl); - mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); - return; + } else { + page = pmd_page(*pmd); + VM_BUG_ON_PAGE(!page_count(page), page); + get_page(page); } - page = pmd_page(*pmd); - VM_BUG_ON_PAGE(!page_count(page), page); - get_page(page); + unlock: spin_unlock(ptl); mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); - split_huge_page(page); + if (!page) + return; + split_huge_page(page); put_page(page); /* -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
