C++ page_mapped函数代码示例

void __flush_anon_page(struct page *page, unsigned long vmaddr)
{
#ifdef CONFIG_RALINK_SOC
	if (!PageHighMem(page)) {
		unsigned long addr = (unsigned long) page_address(page);

		if (pages_do_alias(addr, vmaddr & PAGE_MASK)) {
			if (page_mapped(page) && !Page_dcache_dirty(page)) {
				void *kaddr;

				kaddr = kmap_coherent(page, vmaddr);
				flush_data_cache_page((unsigned long)kaddr);
				kunmap_coherent();
			} else {
				flush_data_cache_page(addr);
				ClearPageDcacheDirty(page);
			}
		}
	} else {
		void *laddr = lowmem_page_address(page);

		if (pages_do_alias((unsigned long)laddr, vmaddr & PAGE_MASK)) {
			if (page_mapped(page) && !Page_dcache_dirty(page)) {
				void *kaddr;

				kaddr = kmap_coherent(page, vmaddr);
				flush_data_cache_page((unsigned long)kaddr);
				kunmap_coherent();
			} else {
				void *kaddr;

				kaddr = kmap_atomic(page, KM_PTE1);
				flush_data_cache_page((unsigned long)kaddr);
				kunmap_atomic(kaddr, KM_PTE1);
				ClearPageDcacheDirty(page);
			}
		}
	}
#else
	unsigned long addr = (unsigned long) page_address(page);

	if (pages_do_alias(addr, vmaddr)) {
		if (page_mapped(page) && !Page_dcache_dirty(page)) {
			void *kaddr;

			kaddr = kmap_coherent(page, vmaddr);
			flush_data_cache_page((unsigned long)kaddr);
			kunmap_coherent();
		} else
			flush_data_cache_page(addr);
	}
#endif
}

/**
 * invalidate_inode_pages2 - remove all unmapped pages from an address_space
 * @mapping - the address_space
 *
 * invalidate_inode_pages2() is like truncate_inode_pages(), except for the case
 * where the page is seen to be mapped into process pagetables.  In that case,
 * the page is marked clean but is left attached to its address_space.
 *
 * The page is also marked not uptodate so that a subsequent pagefault will
 * perform I/O to bringthe page's contents back into sync with its backing
 * store.
 *
 * FIXME: invalidate_inode_pages2() is probably trivially livelockable.
 */
void invalidate_inode_pages2(struct address_space *mapping)
{
	struct pagevec pvec;
	pgoff_t next = 0;
	int i;

	pagevec_init(&pvec, 0);
	while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];

			lock_page(page);
			if (page->mapping == mapping) {	/* truncate race? */
				wait_on_page_writeback(page);
				next = page->index + 1;
				if (page_mapped(page)) {
					clear_page_dirty(page);
					ClearPageUptodate(page);
				} else {
					if (!invalidate_complete_page(mapping,
								      page)) {
						clear_page_dirty(page);
						ClearPageUptodate(page);
					}
				}
			}
			unlock_page(page);
		}
		pagevec_release(&pvec);
		cond_resched();
	}
}

/*
 * Check that TLB entries with kernel ASID (1) have kernel VMA (>= TASK_SIZE),
 * and TLB entries with user ASID (>=4) have VMA < TASK_SIZE.
 *
 * Check that valid TLB entries either have the same PA as the PTE, or PTE is
 * marked as non-present. Non-present PTE and the page with non-zero refcount
 * and zero mapcount is normal for batched TLB flush operation. Zero refcount
 * means that the page was freed prematurely. Non-zero mapcount is unusual,
 * but does not necessary means an error, thus marked as suspicious.
 */
static int check_tlb_entry(unsigned w, unsigned e, bool dtlb)
{
	unsigned tlbidx = w | (e << PAGE_SHIFT);
	unsigned r0 = dtlb ?
		read_dtlb_virtual(tlbidx) : read_itlb_virtual(tlbidx);
	unsigned vpn = (r0 & PAGE_MASK) | (e << PAGE_SHIFT);
	unsigned pte = get_pte_for_vaddr(vpn);
	unsigned mm_asid = (get_rasid_register() >> 8) & ASID_MASK;
	unsigned tlb_asid = r0 & ASID_MASK;
	bool kernel = tlb_asid == 1;
	int rc = 0;

	if (tlb_asid > 0 && ((vpn < TASK_SIZE) == kernel)) {
		pr_err("%cTLB: way: %u, entry: %u, VPN %08x in %s PTE\n",
				dtlb ? 'D' : 'I', w, e, vpn,
				kernel ? "kernel" : "user");
		rc |= TLB_INSANE;
	}

	if (tlb_asid == mm_asid) {
		unsigned r1 = dtlb ? read_dtlb_translation(tlbidx) :
			read_itlb_translation(tlbidx);
		if ((pte ^ r1) & PAGE_MASK) {
			pr_err("%cTLB: way: %u, entry: %u, mapping: %08x->%08x, PTE: %08x\n",
					dtlb ? 'D' : 'I', w, e, r0, r1, pte);
			if (pte == 0 || !pte_present(__pte(pte))) {
				struct page *p = pfn_to_page(r1 >> PAGE_SHIFT);
				pr_err("page refcount: %d, mapcount: %d\n",
						page_count(p),
						page_mapcount(p));
				if (!page_count(p))
					rc |= TLB_INSANE;
				else if (page_mapped(p))
					rc |= TLB_SUSPICIOUS;
			} else {

void copy_user_highpage(struct page *to, struct page *from,
			unsigned long vaddr, struct vm_area_struct *vma)
{
	void *vfrom, *vto;

	vto = kmap_atomic(to);

	if (boot_cpu_data.dcache.n_aliases && page_mapped(from) &&
	    test_bit(PG_dcache_clean, &from->flags)) {
		vfrom = kmap_coherent(from, vaddr);
		copy_page(vto, vfrom);
		kunmap_coherent(vfrom);
	} else {
		vfrom = kmap_atomic(from);
		copy_page(vto, vfrom);
		kunmap_atomic(vfrom);
	}

	if (pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK) ||
	    (vma->vm_flags & VM_EXEC))
		__flush_purge_region(vto, PAGE_SIZE);

	kunmap_atomic(vto);
	/* Make sure this page is cleared on other CPU's too before using it */
	smp_wmb();
}

void __update_cache(struct vm_area_struct *vma, unsigned long address,
	pte_t pte)
{
	struct page *page;
	unsigned long pfn, addr;
	int exec = (vma->vm_flags & VM_EXEC) && !cpu_has_ic_fills_f_dc;

	pfn = pte_pfn(pte);
	if (unlikely(!pfn_valid(pfn))) {
		wmb();
		return;
	}
	page = pfn_to_page(pfn);
	if (page_mapped(page) && Page_dcache_dirty(page)) {
		void *kaddr = NULL;
		if (PageHighMem(page)) {
			addr = (unsigned long)kmap_atomic(page);
			kaddr = (void *)addr;
		} else
			addr = (unsigned long) page_address(page);
		if (exec || (cpu_has_dc_aliases &&
		    pages_do_alias(addr, address & PAGE_MASK))) {
			flush_data_cache_page(addr);
			ClearPageDcacheDirty(page);
		}

		if (kaddr)
			kunmap_atomic((void *)kaddr);
	}
	wmb();  /* finish any outstanding arch cache flushes before ret to user */
}

/**
 * free_swap_cache:page从交换区高速缓存中删除
 */
static inline void free_swap_cache(struct page *page)
{
	if (PageSwapCache(page) && !page_mapped(page) && trylock_page(page)) {
		try_to_free_swap(page);
		unlock_page(page);
	}
}

/*
 * Handle cache congruency of kernel and userspace mappings of page when kernel
 * writes-to/reads-from
 *
 * The idea is to defer flushing of kernel mapping after a WRITE, possible if:
 *  -dcache is NOT aliasing, hence any U/K-mappings of page are congruent
 *  -U-mapping doesn't exist yet for page (finalised in update_mmu_cache)
 *  -In SMP, if hardware caches are coherent
 *
 * There's a corollary case, where kernel READs from a userspace mapped page.
 * If the U-mapping is not congruent to to K-mapping, former needs flushing.
 */
void flush_dcache_page(struct page *page)
{
	struct address_space *mapping;

	if (!cache_is_vipt_aliasing()) {
		clear_bit(PG_dc_clean, &page->flags);
		return;
	}

	/* don't handle anon pages here */
	mapping = page_mapping(page);
	if (!mapping)
		return;

	/*
	 * pagecache page, file not yet mapped to userspace
	 * Make a note that K-mapping is dirty
	 */
	if (!mapping_mapped(mapping)) {
		clear_bit(PG_dc_clean, &page->flags);
	} else if (page_mapped(page)) {

		/* kernel reading from page with U-mapping */
		void *paddr = page_address(page);
		unsigned long vaddr = page->index << PAGE_CACHE_SHIFT;

		if (addr_not_cache_congruent(paddr, vaddr))
			__flush_dcache_page(paddr, vaddr);
	}
}

int truncate_inode_page(struct address_space *mapping, struct page *page)
{
    if (page_mapped(page)) {
        unmap_mapping_range(mapping,
                            (loff_t)page->index << PAGE_CACHE_SHIFT,
                            PAGE_CACHE_SIZE, 0);
    }
    return truncate_complete_page(mapping, page);
}

/**
 * __replace_page - replace page in vma by new page.
 * based on replace_page in mm/ksm.c
 *
 * @vma:      vma that holds the pte pointing to page
 * @addr:     address the old @page is mapped at
 * @page:     the cowed page we are replacing by kpage
 * @kpage:    the modified page we replace page by
 *
 * Returns 0 on success, -EFAULT on failure.
 */
static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
				struct page *old_page, struct page *new_page)
{
	struct mm_struct *mm = vma->vm_mm;
	spinlock_t *ptl;
	pte_t *ptep;
	int err;
	/* For mmu_notifiers */
	const unsigned long mmun_start = addr;
	const unsigned long mmun_end   = addr + PAGE_SIZE;
	struct mem_cgroup *memcg;

	err = mem_cgroup_try_charge(new_page, vma->vm_mm, GFP_KERNEL, &memcg,
			false);
	if (err)
		return err;

	/* For try_to_free_swap() and munlock_vma_page() below */
	lock_page(old_page);

	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
	err = -EAGAIN;
	ptep = page_check_address(old_page, mm, addr, &ptl, 0);
	if (!ptep) {
		mem_cgroup_cancel_charge(new_page, memcg, false);
		goto unlock;
	}

	get_page(new_page);
	page_add_new_anon_rmap(new_page, vma, addr, false);
	mem_cgroup_commit_charge(new_page, memcg, false, false);
	lru_cache_add_active_or_unevictable(new_page, vma);

	if (!PageAnon(old_page)) {
		dec_mm_counter(mm, mm_counter_file(old_page));
		inc_mm_counter(mm, MM_ANONPAGES);
	}

	flush_cache_page(vma, addr, pte_pfn(*ptep));
	ptep_clear_flush_notify(vma, addr, ptep);
	set_pte_at_notify(mm, addr, ptep, mk_pte(new_page, vma->vm_page_prot));

	page_remove_rmap(old_page, false);
	if (!page_mapped(old_page))
		try_to_free_swap(old_page);
	pte_unmap_unlock(ptep, ptl);

	if (vma->vm_flags & VM_LOCKED)
		munlock_vma_page(old_page);
	put_page(old_page);

	err = 0;
 unlock:
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
	unlock_page(old_page);
	return err;
}

/*
 * Safely invalidate one page from its pagecache mapping.
 * It only drops clean, unused pages. The page must be locked.
 *
 * Returns 1 if the page is successfully invalidated, otherwise 0.
 */
int invalidate_inode_page(struct page *page)
{
    struct address_space *mapping = page_mapping(page);
    if (!mapping)
        return 0;
    if (PageDirty(page) || PageWriteback(page))
        return 0;
    if (page_mapped(page))
        return 0;
    return invalidate_complete_page(mapping, page);
}

static int tux3_set_page_dirty_bug(struct page *page)
{
	/* See comment of tux3_set_page_dirty() */
	ClearPageReclaim(page);

	assert(0);
	/* This page should not be mmapped */
	assert(!page_mapped(page));
	/* This page should be dirty already, otherwise we will lost data. */
	assert(PageDirty(page));
	return 0;
}

int truncate_inode_page(struct address_space *mapping, struct page *page)
{
	loff_t holelen;
	VM_BUG_ON_PAGE(PageTail(page), page);

	holelen = PageTransHuge(page) ? HPAGE_PMD_SIZE : PAGE_SIZE;
	if (page_mapped(page)) {
		unmap_mapping_range(mapping,
				   (loff_t)page->index << PAGE_SHIFT,
				   holelen, 0);
	}
	return truncate_complete_page(mapping, page);
}

void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
			 unsigned long vaddr, void *dst, const void *src,
			 unsigned long len)
{
	if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
	    test_bit(PG_dcache_clean, &page->flags)) {
		void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
		memcpy(dst, vfrom, len);
		kunmap_coherent(vfrom);
	} else {
		memcpy(dst, src, len);
		if (boot_cpu_data.dcache.n_aliases)
			clear_bit(PG_dcache_clean, &page->flags);
	}
}

void __flush_anon_page(struct page *page, unsigned long vmaddr)
{
	unsigned long addr = (unsigned long) page_address(page);

	if (pages_do_alias(addr, vmaddr)) {
		if (page_mapped(page) && !Page_dcache_dirty(page)) {
			void *kaddr;

			kaddr = kmap_coherent(page, vmaddr);
			flush_data_cache_page((unsigned long)kaddr);
			kunmap_coherent();
		} else
			flush_data_cache_page(addr);
	}
}

/*
 * If the page can not be invalidated, it is moved to the
 * inactive list to speed up its reclaim.  It is moved to the
 * head of the list, rather than the tail, to give the flusher
 * threads some time to write it out, as this is much more
 * effective than the single-page writeout from reclaim.
 *
 * If the page isn't page_mapped and dirty/writeback, the page
 * could reclaim asap using PG_reclaim.
 *
 * 1. active, mapped page -> none
 * 2. active, dirty/writeback page -> inactive, head, PG_reclaim
 * 3. inactive, mapped page -> none
 * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim
 * 5. inactive, clean -> inactive, tail
 * 6. Others -> none
 *
 * In 4, why it moves inactive's head, the VM expects the page would
 * be write it out by flusher threads as this is much more effective
 * than the single-page writeout from reclaim.
 */
static void lru_deactivate_fn(struct page *page, void *arg)
{
	int lru, file;
	bool active;
	struct zone *zone = page_zone(page);

	if (!PageLRU(page))
		return;

	if (PageUnevictable(page))
		return;

	/* Some processes are using the page */
	if (page_mapped(page))
		return;

	active = PageActive(page);

	file = page_is_file_cache(page);
	lru = page_lru_base_type(page);
	del_page_from_lru_list(zone, page, lru + active);
	ClearPageActive(page);
	ClearPageReferenced(page);
	add_page_to_lru_list(zone, page, lru);

	if (PageWriteback(page) || PageDirty(page)) {
		/*
		 * PG_reclaim could be raced with end_page_writeback
		 * It can make readahead confusing.  But race window
		 * is _really_ small and  it's non-critical problem.
		 */
		SetPageReclaim(page);
	} else {
		struct lruvec *lruvec;
		/*
		 * The page's writeback ends up during pagevec
		 * We moves tha page into tail of inactive.
		 */
		lruvec = mem_cgroup_lru_move_lists(zone, page, lru, lru);
		list_move_tail(&page->lru, &lruvec->lists[lru]);
		__count_vm_event(PGROTATED);
	}

	if (active)
		__count_vm_event(PGDEACTIVATE);
	update_page_reclaim_stat(zone, page, file, 0);
}