/*
* 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. The page still has PageWriteback set, which will pin it.
*
* We don't expect many pages to come through here, so don't bother batching
* things up.
*
* To avoid placing the page at the tail of the LRU while PG_writeback is still
* set, this function will clear PG_writeback before performing the page
* motion. Do that inside the lru lock because once PG_writeback is cleared
* we may not touch the page.
*
* Returns zero if it cleared PG_writeback.
*/
int rotate_reclaimable_page(struct page *page)
{
struct zone *zone;
unsigned long flags;
if (PageLocked(page))
return 1;
if (PageDirty(page))
return 1;
if (PageActive(page))
return 1;
if (!PageLRU(page))
return 1;
zone = page_zone(page);
spin_lock_irqsave(&zone->lru_lock, flags);
if (PageLRU(page) && !PageActive(page)) {
list_del(&page->lru);
list_add_tail(&page->lru, &zone->inactive_list);
inc_page_state(pgrotated);
}
if (!test_clear_page_writeback(page))
BUG();
spin_unlock_irqrestore(&zone->lru_lock, flags);
return 0;
}
/*
* 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.
*
* Returns zero if it cleared PG_writeback.
*/
int rotate_reclaimable_page(struct page *page)
{
struct pagevec *pvec;
unsigned long flags;
if (PageLocked(page))
return 1;
if (PageDirty(page))
return 1;
if (PageActive(page))
return 1;
if (!PageLRU(page))
return 1;
page_cache_get(page);
local_irq_save(flags);
pvec = &__get_cpu_var(lru_rotate_pvecs);
if (!pagevec_add(pvec, page))
pagevec_move_tail(pvec);
local_irq_restore(flags);
if (!test_clear_page_writeback(page))
BUG();
return 0;
}
