diff options
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 127 |
1 files changed, 82 insertions, 45 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index b49579c7f2a5..7d57af21f49e 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -653,6 +653,7 @@ static void free_huge_page(struct page *page) BUG_ON(page_count(page)); BUG_ON(page_mapcount(page)); restore_reserve = PagePrivate(page); + ClearPagePrivate(page); spin_lock(&hugetlb_lock); hugetlb_cgroup_uncharge_page(hstate_index(h), @@ -695,8 +696,22 @@ static void prep_compound_gigantic_page(struct page *page, unsigned long order) /* we rely on prep_new_huge_page to set the destructor */ set_compound_order(page, order); __SetPageHead(page); + __ClearPageReserved(page); for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { __SetPageTail(p); + /* + * For gigantic hugepages allocated through bootmem at + * boot, it's safer to be consistent with the not-gigantic + * hugepages and clear the PG_reserved bit from all tail pages + * too. Otherwse drivers using get_user_pages() to access tail + * pages may get the reference counting wrong if they see + * PG_reserved set on a tail page (despite the head page not + * having PG_reserved set). Enforcing this consistency between + * head and tail pages allows drivers to optimize away a check + * on the head page when they need know if put_page() is needed + * after get_user_pages(). + */ + __ClearPageReserved(p); set_page_count(p, 0); p->first_page = page; } @@ -1329,9 +1344,9 @@ static void __init gather_bootmem_prealloc(void) #else page = virt_to_page(m); #endif - __ClearPageReserved(page); WARN_ON(page_count(page) != 1); prep_compound_huge_page(page, h->order); + WARN_ON(PageReserved(page)); prep_new_huge_page(h, page, page_to_nid(page)); /* * If we had gigantic hugepages allocated at boot time, we need @@ -2361,6 +2376,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { + spinlock_t *src_ptl, *dst_ptl; src_pte = huge_pte_offset(src, addr); if (!src_pte) continue; @@ -2372,8 +2388,9 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, if (dst_pte == src_pte) continue; - spin_lock(&dst->page_table_lock); - spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); + dst_ptl = huge_pte_lock(h, dst, dst_pte); + src_ptl = huge_pte_lockptr(h, src, src_pte); + spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); if (!huge_pte_none(huge_ptep_get(src_pte))) { if (cow) huge_ptep_set_wrprotect(src, addr, src_pte); @@ -2383,8 +2400,8 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, page_dup_rmap(ptepage); set_huge_pte_at(dst, addr, dst_pte, entry); } - spin_unlock(&src->page_table_lock); - spin_unlock(&dst->page_table_lock); + spin_unlock(src_ptl); + spin_unlock(dst_ptl); } return 0; @@ -2427,6 +2444,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long address; pte_t *ptep; pte_t pte; + spinlock_t *ptl; struct page *page; struct hstate *h = hstate_vma(vma); unsigned long sz = huge_page_size(h); @@ -2440,25 +2458,25 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, tlb_start_vma(tlb, vma); mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); again: - spin_lock(&mm->page_table_lock); for (address = start; address < end; address += sz) { ptep = huge_pte_offset(mm, address); if (!ptep) continue; + ptl = huge_pte_lock(h, mm, ptep); if (huge_pmd_unshare(mm, &address, ptep)) - continue; + goto unlock; pte = huge_ptep_get(ptep); if (huge_pte_none(pte)) - continue; + goto unlock; /* * HWPoisoned hugepage is already unmapped and dropped reference */ if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { huge_pte_clear(mm, address, ptep); - continue; + goto unlock; } page = pte_page(pte); @@ -2469,7 +2487,7 @@ again: */ if (ref_page) { if (page != ref_page) - continue; + goto unlock; /* * Mark the VMA as having unmapped its page so that @@ -2486,13 +2504,18 @@ again: page_remove_rmap(page); force_flush = !__tlb_remove_page(tlb, page); - if (force_flush) + if (force_flush) { + spin_unlock(ptl); break; + } /* Bail out after unmapping reference page if supplied */ - if (ref_page) + if (ref_page) { + spin_unlock(ptl); break; + } +unlock: + spin_unlock(ptl); } - spin_unlock(&mm->page_table_lock); /* * mmu_gather ran out of room to batch pages, we break out of * the PTE lock to avoid doing the potential expensive TLB invalidate @@ -2598,7 +2621,7 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, */ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *ptep, pte_t pte, - struct page *pagecache_page) + struct page *pagecache_page, spinlock_t *ptl) { struct hstate *h = hstate_vma(vma); struct page *old_page, *new_page; @@ -2632,8 +2655,8 @@ retry_avoidcopy: page_cache_get(old_page); - /* Drop page_table_lock as buddy allocator may be called */ - spin_unlock(&mm->page_table_lock); + /* Drop page table lock as buddy allocator may be called */ + spin_unlock(ptl); new_page = alloc_huge_page(vma, address, outside_reserve); if (IS_ERR(new_page)) { @@ -2651,13 +2674,13 @@ retry_avoidcopy: BUG_ON(huge_pte_none(pte)); if (unmap_ref_private(mm, vma, old_page, address)) { BUG_ON(huge_pte_none(pte)); - spin_lock(&mm->page_table_lock); + spin_lock(ptl); ptep = huge_pte_offset(mm, address & huge_page_mask(h)); if (likely(pte_same(huge_ptep_get(ptep), pte))) goto retry_avoidcopy; /* - * race occurs while re-acquiring page_table_lock, and - * our job is done. + * race occurs while re-acquiring page table + * lock, and our job is done. */ return 0; } @@ -2665,7 +2688,7 @@ retry_avoidcopy: } /* Caller expects lock to be held */ - spin_lock(&mm->page_table_lock); + spin_lock(ptl); if (err == -ENOMEM) return VM_FAULT_OOM; else @@ -2680,7 +2703,7 @@ retry_avoidcopy: page_cache_release(new_page); page_cache_release(old_page); /* Caller expects lock to be held */ - spin_lock(&mm->page_table_lock); + spin_lock(ptl); return VM_FAULT_OOM; } @@ -2692,10 +2715,10 @@ retry_avoidcopy: mmun_end = mmun_start + huge_page_size(h); mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); /* - * Retake the page_table_lock to check for racing updates + * Retake the page table lock to check for racing updates * before the page tables are altered */ - spin_lock(&mm->page_table_lock); + spin_lock(ptl); ptep = huge_pte_offset(mm, address & huge_page_mask(h)); if (likely(pte_same(huge_ptep_get(ptep), pte))) { ClearPagePrivate(new_page); @@ -2709,13 +2732,13 @@ retry_avoidcopy: /* Make the old page be freed below */ new_page = old_page; } - spin_unlock(&mm->page_table_lock); + spin_unlock(ptl); mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); page_cache_release(new_page); page_cache_release(old_page); /* Caller expects lock to be held */ - spin_lock(&mm->page_table_lock); + spin_lock(ptl); return 0; } @@ -2763,6 +2786,7 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, struct page *page; struct address_space *mapping; pte_t new_pte; + spinlock_t *ptl; /* * Currently, we are forced to kill the process in the event the @@ -2849,7 +2873,8 @@ retry: goto backout_unlocked; } - spin_lock(&mm->page_table_lock); + ptl = huge_pte_lockptr(h, mm, ptep); + spin_lock(ptl); size = i_size_read(mapping->host) >> huge_page_shift(h); if (idx >= size) goto backout; @@ -2870,16 +2895,16 @@ retry: if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { /* Optimization, do the COW without a second fault */ - ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); + ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl); } - spin_unlock(&mm->page_table_lock); + spin_unlock(ptl); unlock_page(page); out: return ret; backout: - spin_unlock(&mm->page_table_lock); + spin_unlock(ptl); backout_unlocked: unlock_page(page); put_page(page); @@ -2891,6 +2916,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, { pte_t *ptep; pte_t entry; + spinlock_t *ptl; int ret; struct page *page = NULL; struct page *pagecache_page = NULL; @@ -2903,7 +2929,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (ptep) { entry = huge_ptep_get(ptep); if (unlikely(is_hugetlb_entry_migration(entry))) { - migration_entry_wait_huge(mm, ptep); + migration_entry_wait_huge(vma, mm, ptep); return 0; } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) return VM_FAULT_HWPOISON_LARGE | @@ -2959,17 +2985,18 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (page != pagecache_page) lock_page(page); - spin_lock(&mm->page_table_lock); + ptl = huge_pte_lockptr(h, mm, ptep); + spin_lock(ptl); /* Check for a racing update before calling hugetlb_cow */ if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) - goto out_page_table_lock; + goto out_ptl; if (flags & FAULT_FLAG_WRITE) { if (!huge_pte_write(entry)) { ret = hugetlb_cow(mm, vma, address, ptep, entry, - pagecache_page); - goto out_page_table_lock; + pagecache_page, ptl); + goto out_ptl; } entry = huge_pte_mkdirty(entry); } @@ -2978,8 +3005,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, flags & FAULT_FLAG_WRITE)) update_mmu_cache(vma, address, ptep); -out_page_table_lock: - spin_unlock(&mm->page_table_lock); +out_ptl: + spin_unlock(ptl); if (pagecache_page) { unlock_page(pagecache_page); @@ -3005,9 +3032,9 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long remainder = *nr_pages; struct hstate *h = hstate_vma(vma); - spin_lock(&mm->page_table_lock); while (vaddr < vma->vm_end && remainder) { pte_t *pte; + spinlock_t *ptl = NULL; int absent; struct page *page; @@ -3015,8 +3042,12 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, * Some archs (sparc64, sh*) have multiple pte_ts to * each hugepage. We have to make sure we get the * first, for the page indexing below to work. + * + * Note that page table lock is not held when pte is null. */ pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); + if (pte) + ptl = huge_pte_lock(h, mm, pte); absent = !pte || huge_pte_none(huge_ptep_get(pte)); /* @@ -3028,6 +3059,8 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, */ if (absent && (flags & FOLL_DUMP) && !hugetlbfs_pagecache_present(h, vma, vaddr)) { + if (pte) + spin_unlock(ptl); remainder = 0; break; } @@ -3047,10 +3080,10 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, !huge_pte_write(huge_ptep_get(pte)))) { int ret; - spin_unlock(&mm->page_table_lock); + if (pte) + spin_unlock(ptl); ret = hugetlb_fault(mm, vma, vaddr, (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); - spin_lock(&mm->page_table_lock); if (!(ret & VM_FAULT_ERROR)) continue; @@ -3081,8 +3114,8 @@ same_page: */ goto same_page; } + spin_unlock(ptl); } - spin_unlock(&mm->page_table_lock); *nr_pages = remainder; *position = vaddr; @@ -3103,13 +3136,15 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma, flush_cache_range(vma, address, end); mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); - spin_lock(&mm->page_table_lock); for (; address < end; address += huge_page_size(h)) { + spinlock_t *ptl; ptep = huge_pte_offset(mm, address); if (!ptep) continue; + ptl = huge_pte_lock(h, mm, ptep); if (huge_pmd_unshare(mm, &address, ptep)) { pages++; + spin_unlock(ptl); continue; } if (!huge_pte_none(huge_ptep_get(ptep))) { @@ -3119,8 +3154,8 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma, set_huge_pte_at(mm, address, ptep, pte); pages++; } + spin_unlock(ptl); } - spin_unlock(&mm->page_table_lock); /* * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare * may have cleared our pud entry and done put_page on the page table: @@ -3283,6 +3318,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) unsigned long saddr; pte_t *spte = NULL; pte_t *pte; + spinlock_t *ptl; if (!vma_shareable(vma, addr)) return (pte_t *)pmd_alloc(mm, pud, addr); @@ -3305,13 +3341,14 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) if (!spte) goto out; - spin_lock(&mm->page_table_lock); + ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte); + spin_lock(ptl); if (pud_none(*pud)) pud_populate(mm, pud, (pmd_t *)((unsigned long)spte & PAGE_MASK)); else put_page(virt_to_page(spte)); - spin_unlock(&mm->page_table_lock); + spin_unlock(ptl); out: pte = (pte_t *)pmd_alloc(mm, pud, addr); mutex_unlock(&mapping->i_mmap_mutex); @@ -3325,7 +3362,7 @@ out: * indicated by page_count > 1, unmap is achieved by clearing pud and * decrementing the ref count. If count == 1, the pte page is not shared. * - * called with vma->vm_mm->page_table_lock held. + * called with page table lock held. * * returns: 1 successfully unmapped a shared pte page * 0 the underlying pte page is not shared, or it is the last user |