C++ PageActive函数代码示例

/*
 * FIXME: speed this up?
 */
void activate_page(struct page *page)
{
    struct zone *zone = page_zone(page);

    spin_lock_irq(&zone->lru_lock);
    if (PageLRU(page) && !PageActive(page)) {
        del_page_from_inactive_list(zone, page);
        SetPageActive(page);
        add_page_to_active_list(zone, page);
        __count_vm_event(PGACTIVATE);
        mem_cgroup_move_lists(page, true);
    }
    spin_unlock_irq(&zone->lru_lock);
}

static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
				 void *arg)
{
	int file = page_is_file_cache(page);
	int active = PageActive(page);
	enum lru_list lru = page_lru(page);

	VM_BUG_ON(PageLRU(page));

	SetPageLRU(page);
	add_page_to_lru_list(page, lruvec, lru);
	update_page_reclaim_stat(lruvec, file, active);
	trace_mm_lru_insertion(page, page_to_pfn(page), lru, trace_pagemap_flags(page));
}

static void pagevec_move_tail_fn(struct page *page, void *arg)
{
	int *pgmoved = arg;

	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
		enum lru_list lru = page_lru_base_type(page);
		struct lruvec *lruvec;

		lruvec = mem_cgroup_lru_move_lists(page_zone(page),
						   page, lru, lru);
		list_move_tail(&page->lru, &lruvec->lists[lru]);
		(*pgmoved)++;
	}
}

/*
 * Writeback is about to end against a page which has been marked for immediate
 * reclaim.  If it still appears to be reclaimable, move it to the tail of the
 * inactive list.
 */
void rotate_reclaimable_page(struct page *page)
{
	if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) &&
	    !PageUnevictable(page) && PageLRU(page)) {
		struct pagevec *pvec;
		unsigned long flags;

		get_page(page);
		local_irq_save(flags);
		pvec = this_cpu_ptr(&lru_rotate_pvecs);
		if (!pagevec_add(pvec, page) || PageCompound(page))
			pagevec_move_tail(pvec);
		local_irq_restore(flags);
	}
}

/* used by __split_huge_page_refcount() */
void lru_add_page_tail(struct page *page, struct page *page_tail,
		       struct lruvec *lruvec)
{
	int uninitialized_var(active);
	enum lru_list lru;
	const int file = 0;

	VM_BUG_ON(!PageHead(page));
	VM_BUG_ON(PageCompound(page_tail));
	VM_BUG_ON(PageLRU(page_tail));
	VM_BUG_ON(NR_CPUS != 1 &&
		  !spin_is_locked(&lruvec_zone(lruvec)->lru_lock));

	SetPageLRU(page_tail);

	if (page_evictable(page_tail, NULL)) {
		if (PageActive(page)) {
			SetPageActive(page_tail);
			active = 1;
			lru = LRU_ACTIVE_ANON;
		} else {
			active = 0;
			lru = LRU_INACTIVE_ANON;
		}
	} else {
		SetPageUnevictable(page_tail);
		lru = LRU_UNEVICTABLE;
	}

	if (likely(PageLRU(page)))
		list_add_tail(&page_tail->lru, &page->lru);
	else {
		struct list_head *list_head;
		/*
		 * Head page has not yet been counted, as an hpage,
		 * so we must account for each subpage individually.
		 *
		 * Use the standard add function to put page_tail on the list,
		 * but then correct its position so they all end up in order.
		 */
		add_page_to_lru_list(page_tail, lruvec, lru);
		list_head = page_tail->lru.prev;
		list_move_tail(&page_tail->lru, list_head);
	}

	if (!PageUnevictable(page))
		update_page_reclaim_stat(lruvec, file, active);
}

// refill_inactive_scan - try to move page in swap_active_list into swap_inactive_list
void
refill_inactive_scan(void) {
    size_t maxscan = nr_active_pages;
    list_entry_t *list = &(active_list.swap_list), *le = list_next(list);
    while (maxscan -- > 0 && le != list) {
        struct Page *page = le2page(le, swap_link);
        le = list_next(le);
        if (!(PageSwap(page) && PageActive(page))) {
            panic("active: wrong swap list.\n");
        }
        if (page_ref(page) == 0) {
            swap_list_del(page);
            swap_inactive_list_add(page);
        }
    }
}

static void __activate_page(struct page *page, struct lruvec *lruvec,
			    void *arg)
{
	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
		int file = page_is_file_cache(page);
		int lru = page_lru_base_type(page);

		del_page_from_lru_list(page, lruvec, lru);
		SetPageActive(page);
		lru += LRU_ACTIVE;
		add_page_to_lru_list(page, lruvec, lru);

		__count_vm_event(PGACTIVATE);
		update_page_reclaim_stat(lruvec, file, 1);
	}
}

static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
			    void *arg)
{
	if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
		int file = page_is_file_cache(page);
		int lru = page_lru_base_type(page);

		del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE);
		ClearPageActive(page);
		ClearPageReferenced(page);
		add_page_to_lru_list(page, lruvec, lru);

		__count_vm_event(PGDEACTIVATE);
		update_page_reclaim_stat(lruvec, file, 0);
	}
}

/*
 * 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);
}

static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
				 void *arg)
{
	enum lru_list lru = (enum lru_list)arg;
	int file = is_file_lru(lru);
	int active = is_active_lru(lru);

	VM_BUG_ON(PageActive(page));
	VM_BUG_ON(PageUnevictable(page));
	VM_BUG_ON(PageLRU(page));

	SetPageLRU(page);
	if (active)
		SetPageActive(page);
	add_page_to_lru_list(page, lruvec, lru);
	update_page_reclaim_stat(lruvec, file, active);
}

/*
 * added by qijiwen.
 * put the page on the lru directly 
*/
void add_page_to_lru_list_cma(struct page *page, enum lru_list lru)
{
	struct zone *zone = page_zone(page);
	int file = is_file_lru(lru);
	int active = is_active_lru(lru);
	unsigned long flags = 0;

	VM_BUG_ON(PageActive(page));
	VM_BUG_ON(PageUnevictable(page));
	VM_BUG_ON(PageLRU(page));

	spin_lock_irqsave(&zone->lru_lock, flags);
	SetPageLRU(page);
	if (active)
		SetPageActive(page);
	update_page_reclaim_stat(zone, page, file, active);
	add_page_to_lru_list(zone, page, lru);
	spin_unlock_irqrestore(&zone->lru_lock, flags);
}

/*
 * FIXME: speed this up?
 */
void activate_page(struct page *page)
{
	struct zone *zone = page_zone(page);

	spin_lock_irq(&zone->lru_lock);
	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
		int file = page_is_file_cache(page);
		int lru = LRU_BASE + file;
		del_page_from_lru_list(zone, page, lru);

		SetPageActive(page);
		lru += LRU_ACTIVE;
		add_page_to_lru_list(zone, page, lru);
		__count_vm_event(PGACTIVATE);
		mem_cgroup_move_lists(page, lru);

		zone->recent_rotated[!!file]++;
		zone->recent_scanned[!!file]++;
	}
	spin_unlock_irq(&zone->lru_lock);
}

/*
 * Isolate one page from the LRU lists. If successful put it onto
 * the indicated list with elevated page count.
 *
 * Result:
 *  -EBUSY: page not on LRU list
 *  0: page removed from LRU list and added to the specified list.
 */
int isolate_lru_page(struct page *page, struct list_head *pagelist)
{
	int ret = -EBUSY;

	if (PageLRU(page)) {
		struct zone *zone = page_zone(page);

		spin_lock_irq(&zone->lru_lock);
		if (PageLRU(page) && get_page_unless_zero(page)) {
			ret = 0;
			ClearPageLRU(page);
			if (PageActive(page))
				del_page_from_active_list(zone, page);
			else
				del_page_from_inactive_list(zone, page);
			list_add_tail(&page->lru, pagelist);
		}
		spin_unlock_irq(&zone->lru_lock);
	}
	return ret;
}

static struct page * rmqueue(zone_t *zone, unsigned int order)
{
	free_area_t * area = zone->free_area + order;
	unsigned int curr_order = order;
	struct list_head *head, *curr;
	unsigned long flags;
	struct page *page;

	spin_lock_irqsave(&zone->lock, flags);
	do {
		head = &area->free_list;
		curr = head->next;

		if (curr != head) {
			unsigned int index;

			page = list_entry(curr, struct page, list);
			if (BAD_RANGE(zone,page))
				BUG();
			list_del(curr);
			index = page - zone->zone_mem_map;
			if (curr_order != MAX_ORDER-1)
				MARK_USED(index, curr_order, area);
			zone->free_pages -= 1UL << order;

			page = expand(zone, page, index, order, curr_order, area);
			spin_unlock_irqrestore(&zone->lock, flags);

			set_page_count(page, 1);
			if (BAD_RANGE(zone,page))
				BUG();
			if (PageLRU(page))
				BUG();
			if (PageActive(page))
				BUG();
			return page;	
		}
		curr_order++;
		area++;
	} while (curr_order < MAX_ORDER);

// page_launder - try to move page to swap_active_list OR swap_inactive_list, 
//              - and call swap_fs_write to swap out pages in swap_inactive_list
int
page_launder(void) {
    size_t maxscan = nr_inactive_pages, free_count = 0;
    list_entry_t *list = &(inactive_list.swap_list), *le = list_next(list);
    while (maxscan -- > 0 && le != list) {
        struct Page *page = le2page(le, swap_link);
        le = list_next(le);
        if (!(PageSwap(page) && !PageActive(page))) {
            panic("inactive: wrong swap list.\n");
        }
        swap_list_del(page);
        if (page_ref(page) != 0) {
            swap_active_list_add(page);
            continue ;
        }
        swap_entry_t entry = page->index;
        if (!try_free_swap_entry(entry)) {
            if (PageDirty(page)) {
                ClearPageDirty(page);
                swap_duplicate(entry);
                if (swapfs_write(entry, page) != 0) {
                    SetPageDirty(page);
                }
                mem_map[swap_offset(entry)] --;
                if (page_ref(page) != 0) {
                    swap_active_list_add(page);
                    continue ;
                }
                if (PageDirty(page)) {
                    swap_inactive_list_add(page);
                    continue ;
                }
                try_free_swap_entry(entry);
            }
        }
        free_count ++;
        swap_free_page(page);
    }
    return free_count;
}