1 files changed, 216 insertions, 666 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4fe7e3aa02e2..fd572bbdc9f5 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -33,39 +33,21 @@
 #include <linux/cpuset.h>
 #include <linux/notifier.h>
 #include <linux/rwsem.h>
+#include <linux/delay.h>
 
 #include <asm/tlbflush.h>
 #include <asm/div64.h>
 
 #include <linux/swapops.h>
 
-/* possible outcome of pageout() */
-typedef enum {
-        /* failed to write page out, page is locked */
-        PAGE_KEEP,
-        /* move page to the active list, page is locked */
-        PAGE_ACTIVATE,
-        /* page has been sent to the disk successfully, page is unlocked */
-        PAGE_SUCCESS,
-        /* page is clean and locked */
-        PAGE_CLEAN,
-} pageout_t;
+#include "internal.h"
 
 struct scan_control {
-        /* Ask refill_inactive_zone, or shrink_cache to scan this many pages */
-        unsigned long nr_to_scan;
-
         /* Incremented by the number of inactive pages that were scanned */
         unsigned long nr_scanned;
 
-        /* Incremented by the number of pages reclaimed */
-        unsigned long nr_reclaimed;
-
         unsigned long nr_mapped;        /* From page_state */
 
-        /* Ask shrink_caches, or shrink_zone to scan at this priority */
-        unsigned int priority;
-
         /* This context's GFP mask */
         gfp_t gfp_mask;
 
@@ -183,10 +165,11 @@ EXPORT_SYMBOL(remove_shrinker);
  *
  * Returns the number of slab objects which we shrunk.
  */
-int shrink_slab(unsigned long scanned, gfp_t gfp_mask, unsigned long lru_pages)
+unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
+                        unsigned long lru_pages)
 {
         struct shrinker *shrinker;
-        int ret = 0;
+        unsigned long ret = 0;
 
         if (scanned == 0)
                 scanned = SWAP_CLUSTER_MAX;
@@ -306,9 +289,10 @@ static void handle_write_error(struct address_space *mapping,
 }
 
 /*
- * pageout is called by shrink_list() for each dirty page. Calls ->writepage().
+ * pageout is called by shrink_page_list() for each dirty page.
+ * Calls ->writepage().
  */
-static pageout_t pageout(struct page *page, struct address_space *mapping)
+pageout_t pageout(struct page *page, struct address_space *mapping)
 {
         /*
          * If the page is dirty, only perform writeback if that write
@@ -376,7 +360,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping)
         return PAGE_CLEAN;
 }
 
-static int remove_mapping(struct address_space *mapping, struct page *page)
+int remove_mapping(struct address_space *mapping, struct page *page)
 {
         if (!mapping)
                 return 0;               /* truncate got there first */
@@ -414,14 +398,15 @@ cannot_free:
 }
 
 /*
- * shrink_list adds the number of reclaimed pages to sc->nr_reclaimed
+ * shrink_page_list() returns the number of reclaimed pages
  */
-static int shrink_list(struct list_head *page_list, struct scan_control *sc)
+static unsigned long shrink_page_list(struct list_head *page_list,
+                                        struct scan_control *sc)
 {
         LIST_HEAD(ret_pages);
         struct pagevec freed_pvec;
         int pgactivate = 0;
-        int reclaimed = 0;
+        unsigned long nr_reclaimed = 0;
 
         cond_resched();
 
@@ -464,12 +449,9 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
                  * Anonymous process memory has backing store?
                  * Try to allocate it some swap space here.
                  */
-                if (PageAnon(page) && !PageSwapCache(page)) {
-                        if (!sc->may_swap)
-                                goto keep_locked;
+                if (PageAnon(page) && !PageSwapCache(page))
                         if (!add_to_swap(page, GFP_ATOMIC))
                                 goto activate_locked;
-                }
 #endif /* CONFIG_SWAP */
 
                 mapping = page_mapping(page);
@@ -481,12 +463,6 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
                  * processes. Try to unmap it here.
                  */
                 if (page_mapped(page) && mapping) {
-                        /*
-                         * No unmapping if we do not swap
-                         */
-                        if (!sc->may_swap)
-                                goto keep_locked;
-
                         switch (try_to_unmap(page, 0)) {
                         case SWAP_FAIL:
                                 goto activate_locked;
@@ -561,7 +537,7 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
 
 free_it:
                 unlock_page(page);
-                reclaimed++;
+                nr_reclaimed++;
                 if (!pagevec_add(&freed_pvec, page))
                         __pagevec_release_nonlru(&freed_pvec);
                 continue;
@@ -579,483 +555,8 @@ keep:
         if (pagevec_count(&freed_pvec))
                 __pagevec_release_nonlru(&freed_pvec);
         mod_page_state(pgactivate, pgactivate);
-        sc->nr_reclaimed += reclaimed;
-        return reclaimed;
-}
-
-#ifdef CONFIG_MIGRATION
-static inline void move_to_lru(struct page *page)
-{
-        list_del(&page->lru);
-        if (PageActive(page)) {
-                /*
-                 * lru_cache_add_active checks that
-                 * the PG_active bit is off.
-                 */
-                ClearPageActive(page);
-                lru_cache_add_active(page);
-        } else {
-                lru_cache_add(page);
-        }
-        put_page(page);
-}
-
-/*
- * Add isolated pages on the list back to the LRU.
- *
- * returns the number of pages put back.
- */
-int putback_lru_pages(struct list_head *l)
-{
-        struct page *page;
-        struct page *page2;
-        int count = 0;
-
-        list_for_each_entry_safe(page, page2, l, lru) {
-                move_to_lru(page);
-                count++;
-        }
-        return count;
-}
-
-/*
- * Non migratable page
- */
-int fail_migrate_page(struct page *newpage, struct page *page)
-{
-        return -EIO;
-}
-EXPORT_SYMBOL(fail_migrate_page);
-
-/*
- * swapout a single page
- * page is locked upon entry, unlocked on exit
- */
-static int swap_page(struct page *page)
-{
-        struct address_space *mapping = page_mapping(page);
-
-        if (page_mapped(page) && mapping)
-                if (try_to_unmap(page, 1) != SWAP_SUCCESS)
-                        goto unlock_retry;
-
-        if (PageDirty(page)) {
-                /* Page is dirty, try to write it out here */
-                switch(pageout(page, mapping)) {
-                case PAGE_KEEP:
-                case PAGE_ACTIVATE:
-                        goto unlock_retry;
-
-                case PAGE_SUCCESS:
-                        goto retry;
-
-                case PAGE_CLEAN:
-                        ; /* try to free the page below */
-                }
-        }
-
-        if (PagePrivate(page)) {
-                if (!try_to_release_page(page, GFP_KERNEL) ||
-                    (!mapping && page_count(page) == 1))
-                        goto unlock_retry;
-        }
-
-        if (remove_mapping(mapping, page)) {
-                /* Success */
-                unlock_page(page);
-                return 0;
-        }
-
-unlock_retry:
-        unlock_page(page);
-
-retry:
-        return -EAGAIN;
-}
-EXPORT_SYMBOL(swap_page);
-
-/*
- * Page migration was first developed in the context of the memory hotplug
- * project. The main authors of the migration code are:
- *
- * IWAMOTO Toshihiro <iwamoto@valinux.co.jp>
- * Hirokazu Takahashi <taka@valinux.co.jp>
- * Dave Hansen <haveblue@us.ibm.com>
- * Christoph Lameter <clameter@sgi.com>
- */
-
-/*
- * Remove references for a page and establish the new page with the correct
- * basic settings to be able to stop accesses to the page.
- */
-int migrate_page_remove_references(struct page *newpage,
-                                struct page *page, int nr_refs)
-{
-        struct address_space *mapping = page_mapping(page);
-        struct page **radix_pointer;
-
-        /*
-         * Avoid doing any of the following work if the page count
-         * indicates that the page is in use or truncate has removed
-         * the page.
-         */
-        if (!mapping || page_mapcount(page) + nr_refs != page_count(page))
-                return -EAGAIN;
-
-        /*
-         * Establish swap ptes for anonymous pages or destroy pte
-         * maps for files.
-         *
-         * In order to reestablish file backed mappings the fault handlers
-         * will take the radix tree_lock which may then be used to stop
-         * processses from accessing this page until the new page is ready.
-         *
-         * A process accessing via a swap pte (an anonymous page) will take a
-         * page_lock on the old page which will block the process until the
-         * migration attempt is complete. At that time the PageSwapCache bit
-         * will be examined. If the page was migrated then the PageSwapCache
-         * bit will be clear and the operation to retrieve the page will be
-         * retried which will find the new page in the radix tree. Then a new
-         * direct mapping may be generated based on the radix tree contents.
-         *
-         * If the page was not migrated then the PageSwapCache bit
-         * is still set and the operation may continue.
-         */
-        if (try_to_unmap(page, 1) == SWAP_FAIL)
-                /* A vma has VM_LOCKED set -> Permanent failure */
-                return -EPERM;
-
-        /*
-         * Give up if we were unable to remove all mappings.
-         */
-        if (page_mapcount(page))
-                return -EAGAIN;
-
-        write_lock_irq(&mapping->tree_lock);
-
-        radix_pointer = (struct page **)radix_tree_lookup_slot(
-                                                &mapping->page_tree,
-                                                page_index(page));
-
-        if (!page_mapping(page) || page_count(page) != nr_refs ||
-                        *radix_pointer != page) {
-                write_unlock_irq(&mapping->tree_lock);
-                return -EAGAIN;
-        }
-
-        /*
-         * Now we know that no one else is looking at the page.
-         *
-         * Certain minimal information about a page must be available
-         * in order for other subsystems to properly handle the page if they
-         * find it through the radix tree update before we are finished
-         * copying the page.
-         */
-        get_page(newpage);
-        newpage->index = page->index;
-        newpage->mapping = page->mapping;
-        if (PageSwapCache(page)) {
-                SetPageSwapCache(newpage);
-                set_page_private(newpage, page_private(page));
-        }
-
-        *radix_pointer = newpage;
-        __put_page(page);
-        write_unlock_irq(&mapping->tree_lock);
-
-        return 0;
-}
-EXPORT_SYMBOL(migrate_page_remove_references);
-
-/*
- * Copy the page to its new location
- */
-void migrate_page_copy(struct page *newpage, struct page *page)
-{
-        copy_highpage(newpage, page);
-
-        if (PageError(page))
-                SetPageError(newpage);
-        if (PageReferenced(page))
-                SetPageReferenced(newpage);
-        if (PageUptodate(page))
-                SetPageUptodate(newpage);
-        if (PageActive(page))
-                SetPageActive(newpage);
-        if (PageChecked(page))
-                SetPageChecked(newpage);
-        if (PageMappedToDisk(page))
-                SetPageMappedToDisk(newpage);
-
-        if (PageDirty(page)) {
-                clear_page_dirty_for_io(page);
-                set_page_dirty(newpage);
-        }
-
-        ClearPageSwapCache(page);
-        ClearPageActive(page);
-        ClearPagePrivate(page);
-        set_page_private(page, 0);
-        page->mapping = NULL;
-
-        /*
-         * If any waiters have accumulated on the new page then
-         * wake them up.
-         */
-        if (PageWriteback(newpage))
-                end_page_writeback(newpage);
-}
-EXPORT_SYMBOL(migrate_page_copy);
-
-/*
- * Common logic to directly migrate a single page suitable for
- * pages that do not use PagePrivate.
- *
- * Pages are locked upon entry and exit.
- */
-int migrate_page(struct page *newpage, struct page *page)
-{
-        int rc;
-
-        BUG_ON(PageWriteback(page));    /* Writeback must be complete */
-
-        rc = migrate_page_remove_references(newpage, page, 2);
-
-        if (rc)
-                return rc;
-
-        migrate_page_copy(newpage, page);
-
-        /*
-         * Remove auxiliary swap entries and replace
-         * them with real ptes.
-         *
-         * Note that a real pte entry will allow processes that are not
-         * waiting on the page lock to use the new page via the page tables
-         * before the new page is unlocked.
-         */
-        remove_from_swap(newpage);
-        return 0;
+        return nr_reclaimed;
 }
-EXPORT_SYMBOL(migrate_page);
-
-/*
- * migrate_pages
- *
- * Two lists are passed to this function. The first list
- * contains the pages isolated from the LRU to be migrated.
- * The second list contains new pages that the pages isolated
- * can be moved to. If the second list is NULL then all
- * pages are swapped out.
- *
- * The function returns after 10 attempts or if no pages
- * are movable anymore because to has become empty
- * or no retryable pages exist anymore.
- *
- * Return: Number of pages not migrated when "to" ran empty.
- */
-int migrate_pages(struct list_head *from, struct list_head *to,
-                  struct list_head *moved, struct list_head *failed)
-{
-        int retry;
-        int nr_failed = 0;
-        int pass = 0;
-        struct page *page;
-        struct page *page2;
-        int swapwrite = current->flags & PF_SWAPWRITE;
-        int rc;
-
-        if (!swapwrite)
-                current->flags |= PF_SWAPWRITE;
-
-redo:
-        retry = 0;
-
-        list_for_each_entry_safe(page, page2, from, lru) {
-                struct page *newpage = NULL;
-                struct address_space *mapping;
-
-                cond_resched();
-
-                rc = 0;
-                if (page_count(page) == 1)
-                        /* page was freed from under us. So we are done. */
-                        goto next;
-
-                if (to && list_empty(to))
-                        break;
-
-                /*
-                 * Skip locked pages during the first two passes to give the
-                 * functions holding the lock time to release the page. Later we
-                 * use lock_page() to have a higher chance of acquiring the
-                 * lock.
-                 */
-                rc = -EAGAIN;
-                if (pass > 2)
-                        lock_page(page);
-                else
-                        if (TestSetPageLocked(page))
-                                goto next;
-
-                /*
-                 * Only wait on writeback if we have already done a pass where
-                 * we we may have triggered writeouts for lots of pages.
-                 */
-                if (pass > 0) {
-                        wait_on_page_writeback(page);
-                } else {
-                        if (PageWriteback(page))
-                                goto unlock_page;
-                }
-
-                /*
-                 * Anonymous pages must have swap cache references otherwise
-                 * the information contained in the page maps cannot be
-                 * preserved.
-                 */
-                if (PageAnon(page) && !PageSwapCache(page)) {
-                        if (!add_to_swap(page, GFP_KERNEL)) {
-                                rc = -ENOMEM;
-                                goto unlock_page;
-                        }
-                }
-
-                if (!to) {
-                        rc = swap_page(page);
-                        goto next;
-                }
-
-                newpage = lru_to_page(to);
-                lock_page(newpage);
-
-                /*
-                 * Pages are properly locked and writeback is complete.
-                 * Try to migrate the page.
-                 */
-                mapping = page_mapping(page);
-                if (!mapping)
-                        goto unlock_both;
-
-                if (mapping->a_ops->migratepage) {
-                        /*
-                         * Most pages have a mapping and most filesystems
-                         * should provide a migration function. Anonymous
-                         * pages are part of swap space which also has its
-                         * own migration function. This is the most common
-                         * path for page migration.
-                         */
-                        rc = mapping->a_ops->migratepage(newpage, page);
-                        goto unlock_both;
-                }
-
-                /*
-                 * Default handling if a filesystem does not provide
-                 * a migration function. We can only migrate clean
-                 * pages so try to write out any dirty pages first.
-                 */
-                if (PageDirty(page)) {
-                        switch (pageout(page, mapping)) {
-                        case PAGE_KEEP:
-                        case PAGE_ACTIVATE:
-                                goto unlock_both;
-
-                        case PAGE_SUCCESS:
-                                unlock_page(newpage);
-                                goto next;
-
-                        case PAGE_CLEAN:
-                                ; /* try to migrate the page below */
-                        }
-                }
-
-                /*
-                 * Buffers are managed in a filesystem specific way.
-                 * We must have no buffers or drop them.
-                 */
-                if (!page_has_buffers(page) ||
-                    try_to_release_page(page, GFP_KERNEL)) {
-                        rc = migrate_page(newpage, page);
-                        goto unlock_both;
-                }
-
-                /*
-                 * On early passes with mapped pages simply
-                 * retry. There may be a lock held for some
-                 * buffers that may go away. Later
-                 * swap them out.
-                 */
-                if (pass > 4) {
-                        /*
-                         * Persistently unable to drop buffers..... As a
-                         * measure of last resort we fall back to
-                         * swap_page().
-                         */
-                        unlock_page(newpage);
-                        newpage = NULL;
-                        rc = swap_page(page);
-                        goto next;
-                }
-
-unlock_both:
-                unlock_page(newpage);
-
-unlock_page:
-                unlock_page(page);
-
-next:
-                if (rc == -EAGAIN) {
-                        retry++;
-                } else if (rc) {
-                        /* Permanent failure */
-                        list_move(&page->lru, failed);
-                        nr_failed++;
-                } else {
-                        if (newpage) {
-                                /* Successful migration. Return page to LRU */
-                                move_to_lru(newpage);
-                        }
-                        list_move(&page->lru, moved);
-                }
-        }
-        if (retry && pass++ < 10)
-                goto redo;
-
-        if (!swapwrite)
-                current->flags &= ~PF_SWAPWRITE;
-
-        return nr_failed + retry;
-}
-
-/*
- * Isolate one page from the LRU lists and put it on the
- * indicated list with elevated refcount.
- *
- * Result:
- *  0 = page not on LRU list
- *  1 = page removed from LRU list and added to the specified list.
- */
-int isolate_lru_page(struct page *page)
-{
-        int ret = 0;
-
-        if (PageLRU(page)) {
-                struct zone *zone = page_zone(page);
-                spin_lock_irq(&zone->lru_lock);
-                if (TestClearPageLRU(page)) {
-                        ret = 1;
-                        get_page(page);
-                        if (PageActive(page))
-                                del_page_from_active_list(zone, page);
-                        else
-                                del_page_from_inactive_list(zone, page);
-                }
-                spin_unlock_irq(&zone->lru_lock);
-        }
-
-        return ret;
-}
-#endif
 
 /*
  * zone->lru_lock is heavily contended.  Some of the functions that
@@ -1074,32 +575,35 @@ int isolate_lru_page(struct page *page)
  *
  * returns how many pages were moved onto *@dst.
  */
-static int isolate_lru_pages(int nr_to_scan, struct list_head *src,
-                             struct list_head *dst, int *scanned)
+static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
+                struct list_head *src, struct list_head *dst,
+                unsigned long *scanned)
 {
-        int nr_taken = 0;
+        unsigned long nr_taken = 0;
         struct page *page;
-        int scan = 0;
+        unsigned long scan;
 
-        while (scan++ < nr_to_scan && !list_empty(src)) {
+        for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) {
+                struct list_head *target;
                 page = lru_to_page(src);
                 prefetchw_prev_lru_page(page, src, flags);
 
-                if (!TestClearPageLRU(page))
-                        BUG();
+                BUG_ON(!PageLRU(page));
+
                 list_del(&page->lru);
-                if (get_page_testone(page)) {
+                target = src;
+                if (likely(get_page_unless_zero(page))) {
                         /*
-                         * It is being freed elsewhere
+                         * Be careful not to clear PageLRU until after we're
+                         * sure the page is not being freed elsewhere -- the
+                         * page release code relies on it.
                          */
-                        __put_page(page);
-                        SetPageLRU(page);
-                        list_add(&page->lru, src);
-                        continue;
-                } else {
-                        list_add(&page->lru, dst);
+                        ClearPageLRU(page);
+                        target = dst;
                         nr_taken++;
-                }
+                } /* else it is being freed elsewhere */
+
+                list_add(&page->lru, target);
         }
 
         *scanned = scan;
@@ -1107,23 +611,26 @@ static int isolate_lru_pages(int nr_to_scan, struct list_head *src,
 }
 
 /*
- * shrink_cache() adds the number of pages reclaimed to sc->nr_reclaimed
+ * shrink_inactive_list() is a helper for shrink_zone().  It returns the number
+ * of reclaimed pages
  */
-static void shrink_cache(struct zone *zone, struct scan_control *sc)
+static unsigned long shrink_inactive_list(unsigned long max_scan,
+                                struct zone *zone, struct scan_control *sc)
 {
         LIST_HEAD(page_list);
         struct pagevec pvec;
-        int max_scan = sc->nr_to_scan;
+        unsigned long nr_scanned = 0;
+        unsigned long nr_reclaimed = 0;
 
         pagevec_init(&pvec, 1);
 
         lru_add_drain();
         spin_lock_irq(&zone->lru_lock);
-        while (max_scan > 0) {
+        do {
                 struct page *page;
-                int nr_taken;
-                int nr_scan;
-                int nr_freed;
+                unsigned long nr_taken;
+                unsigned long nr_scan;
+                unsigned long nr_freed;
 
                 nr_taken = isolate_lru_pages(sc->swap_cluster_max,
                                              &zone->inactive_list,
@@ -1132,12 +639,9 @@ static void shrink_cache(struct zone *zone, struct scan_control *sc)
                 zone->pages_scanned += nr_scan;
                 spin_unlock_irq(&zone->lru_lock);
 
-                if (nr_taken == 0)
-                        goto done;
-
-                max_scan -= nr_scan;
-                nr_freed = shrink_list(&page_list, sc);
-
+                nr_scanned += nr_scan;
+                nr_freed = shrink_page_list(&page_list, sc);
+                nr_reclaimed += nr_freed;
                 local_irq_disable();
                 if (current_is_kswapd()) {
                         __mod_page_state_zone(zone, pgscan_kswapd, nr_scan);
@@ -1146,14 +650,17 @@ static void shrink_cache(struct zone *zone, struct scan_control *sc)
                         __mod_page_state_zone(zone, pgscan_direct, nr_scan);
                 __mod_page_state_zone(zone, pgsteal, nr_freed);
 
+                if (nr_taken == 0)
+                        goto done;
+
                 spin_lock(&zone->lru_lock);
                 /*
                  * Put back any unfreeable pages.
                  */
                 while (!list_empty(&page_list)) {
                         page = lru_to_page(&page_list);
-                        if (TestSetPageLRU(page))
-                                BUG();
+                        BUG_ON(PageLRU(page));
+                        SetPageLRU(page);
                         list_del(&page->lru);
                         if (PageActive(page))
                                 add_page_to_active_list(zone, page);
@@ -1165,10 +672,12 @@ static void shrink_cache(struct zone *zone, struct scan_control *sc)
                                 spin_lock_irq(&zone->lru_lock);
                         }
                 }
-        }
-        spin_unlock_irq(&zone->lru_lock);
+        } while (nr_scanned < max_scan);
+        spin_unlock(&zone->lru_lock);
 done:
+        local_irq_enable();
         pagevec_release(&pvec);
+        return nr_reclaimed;
 }
 
 /*
@@ -1188,13 +697,12 @@ done:
  * The downside is that we have to touch page->_count against each page.
  * But we had to alter page->flags anyway.
  */
-static void
-refill_inactive_zone(struct zone *zone, struct scan_control *sc)
+static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
+                                struct scan_control *sc)
 {
-        int pgmoved;
+        unsigned long pgmoved;
         int pgdeactivate = 0;
-        int pgscanned;
-        int nr_pages = sc->nr_to_scan;
+        unsigned long pgscanned;
         LIST_HEAD(l_hold);      /* The pages which were snipped off */
         LIST_HEAD(l_inactive);  /* Pages to go onto the inactive_list */
         LIST_HEAD(l_active);    /* Pages to go onto the active_list */
@@ -1202,7 +710,7 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc)
         struct pagevec pvec;
         int reclaim_mapped = 0;
 
-        if (unlikely(sc->may_swap)) {
+        if (sc->may_swap) {
                 long mapped_ratio;
                 long distress;
                 long swap_tendency;
@@ -1272,10 +780,11 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc)
         while (!list_empty(&l_inactive)) {
                 page = lru_to_page(&l_inactive);
                 prefetchw_prev_lru_page(page, &l_inactive, flags);
-                if (TestSetPageLRU(page))
-                        BUG();
-                if (!TestClearPageActive(page))
-                        BUG();
+                BUG_ON(PageLRU(page));
+                SetPageLRU(page);
+                BUG_ON(!PageActive(page));
+                ClearPageActive(page);
+
                 list_move(&page->lru, &zone->inactive_list);
                 pgmoved++;
                 if (!pagevec_add(&pvec, page)) {
@@ -1301,8 +810,8 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc)
         while (!list_empty(&l_active)) {
                 page = lru_to_page(&l_active);
                 prefetchw_prev_lru_page(page, &l_active, flags);
-                if (TestSetPageLRU(page))
-                        BUG();
+                BUG_ON(PageLRU(page));
+                SetPageLRU(page);
                 BUG_ON(!PageActive(page));
                 list_move(&page->lru, &zone->active_list);
                 pgmoved++;
@@ -1327,11 +836,13 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc)
 /*
  * This is a basic per-zone page freer.  Used by both kswapd and direct reclaim.
  */
-static void
-shrink_zone(struct zone *zone, struct scan_control *sc)
+static unsigned long shrink_zone(int priority, struct zone *zone,
+                                struct scan_control *sc)
 {
         unsigned long nr_active;
         unsigned long nr_inactive;
+        unsigned long nr_to_scan;
+        unsigned long nr_reclaimed = 0;
 
         atomic_inc(&zone->reclaim_in_progress);
 
@@ -1339,14 +850,14 @@ shrink_zone(struct zone *zone, struct scan_control *sc)
          * Add one to `nr_to_scan' just to make sure that the kernel will
          * slowly sift through the active list.
          */
-        zone->nr_scan_active += (zone->nr_active >> sc->priority) + 1;
+        zone->nr_scan_active += (zone->nr_active >> priority) + 1;
         nr_active = zone->nr_scan_active;
         if (nr_active >= sc->swap_cluster_max)
                 zone->nr_scan_active = 0;
         else
                 nr_active = 0;
 
-        zone->nr_scan_inactive += (zone->nr_inactive >> sc->priority) + 1;
+        zone->nr_scan_inactive += (zone->nr_inactive >> priority) + 1;
         nr_inactive = zone->nr_scan_inactive;
         if (nr_inactive >= sc->swap_cluster_max)
                 zone->nr_scan_inactive = 0;
@@ -1355,23 +866,25 @@ shrink_zone(struct zone *zone, struct scan_control *sc)
 
         while (nr_active || nr_inactive) {
                 if (nr_active) {
-                        sc->nr_to_scan = min(nr_active,
+                        nr_to_scan = min(nr_active,
                                         (unsigned long)sc->swap_cluster_max);
-                        nr_active -= sc->nr_to_scan;
-                        refill_inactive_zone(zone, sc);
+                        nr_active -= nr_to_scan;
+                        shrink_active_list(nr_to_scan, zone, sc);
                 }
 
                 if (nr_inactive) {
-                        sc->nr_to_scan = min(nr_inactive,
+                        nr_to_scan = min(nr_inactive,
                                         (unsigned long)sc->swap_cluster_max);
-                        nr_inactive -= sc->nr_to_scan;
-                        shrink_cache(zone, sc);
+                        nr_inactive -= nr_to_scan;
+                        nr_reclaimed += shrink_inactive_list(nr_to_scan, zone,
+                                                                sc);
                 }
         }
 
         throttle_vm_writeout();
 
         atomic_dec(&zone->reclaim_in_progress);
+        return nr_reclaimed;
 }
 
 /*
@@ -1390,9 +903,10 @@ shrink_zone(struct zone *zone, struct scan_control *sc)
  * If a zone is deemed to be full of pinned pages then just give it a light
  * scan then give up on it.
  */
-static void
-shrink_caches(struct zone **zones, struct scan_control *sc)
+static unsigned long shrink_zones(int priority, struct zone **zones,
+                                        struct scan_control *sc)
 {
+        unsigned long nr_reclaimed = 0;
         int i;
 
         for (i = 0; zones[i] != NULL; i++) {
@@ -1404,15 +918,16 @@ shrink_caches(struct zone **zones, struct scan_control *sc)
                 if (!cpuset_zone_allowed(zone, __GFP_HARDWALL))
                         continue;
 
-                zone->temp_priority = sc->priority;
-                if (zone->prev_priority > sc->priority)
-                        zone->prev_priority = sc->priority;
+                zone->temp_priority = priority;
+                if (zone->prev_priority > priority)
+                        zone->prev_priority = priority;
 
-                if (zone->all_unreclaimable && sc->priority != DEF_PRIORITY)
+                if (zone->all_unreclaimable && priority != DEF_PRIORITY)
                         continue;       /* Let kswapd poll it */
 
-                shrink_zone(zone, sc);
+                nr_reclaimed += shrink_zone(priority, zone, sc);
         }
+        return nr_reclaimed;
 }
  
 /*
@@ -1428,19 +943,21 @@ shrink_caches(struct zone **zones, struct scan_control *sc)
  * holds filesystem locks which prevent writeout this might not work, and the
  * allocation attempt will fail.
  */
-int try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
+unsigned long try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
 {
         int priority;
         int ret = 0;
-        int total_scanned = 0, total_reclaimed = 0;
+        unsigned long total_scanned = 0;
+        unsigned long nr_reclaimed = 0;
         struct reclaim_state *reclaim_state = current->reclaim_state;
-        struct scan_control sc;
         unsigned long lru_pages = 0;
         int i;
-
-        sc.gfp_mask = gfp_mask;
-        sc.may_writepage = !laptop_mode;
-        sc.may_swap = 1;
+        struct scan_control sc = {
+                .gfp_mask = gfp_mask,
+                .may_writepage = !laptop_mode,
+                .swap_cluster_max = SWAP_CLUSTER_MAX,
+                .may_swap = 1,
+        };
 
         inc_page_state(allocstall);
 
@@ -1457,20 +974,16 @@ int try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
         for (priority = DEF_PRIORITY; priority >= 0; priority--) {
                 sc.nr_mapped = read_page_state(nr_mapped);
                 sc.nr_scanned = 0;
-                sc.nr_reclaimed = 0;
-                sc.priority = priority;
-                sc.swap_cluster_max = SWAP_CLUSTER_MAX;
                 if (!priority)
                         disable_swap_token();
-                shrink_caches(zones, &sc);
+                nr_reclaimed += shrink_zones(priority, zones, &sc);
                 shrink_slab(sc.nr_scanned, gfp_mask, lru_pages);
                 if (reclaim_state) {
-                        sc.nr_reclaimed += reclaim_state->reclaimed_slab;
+                        nr_reclaimed += reclaim_state->reclaimed_slab;
                         reclaim_state->reclaimed_slab = 0;
                 }
                 total_scanned += sc.nr_scanned;
-                total_reclaimed += sc.nr_reclaimed;
-                if (total_reclaimed >= sc.swap_cluster_max) {
+                if (nr_reclaimed >= sc.swap_cluster_max) {
                         ret = 1;
                         goto out;
                 }
@@ -1482,7 +995,8 @@ int try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
                  * that's undesirable in laptop mode, where we *want* lumpy
                  * writeout.  So in laptop mode, write out the whole world.
                  */
-                if (total_scanned > sc.swap_cluster_max + sc.swap_cluster_max/2) {
+                if (total_scanned > sc.swap_cluster_max +
+                                        sc.swap_cluster_max / 2) {
                         wakeup_pdflush(laptop_mode ? 0 : total_scanned);
                         sc.may_writepage = 1;
                 }
@@ -1528,22 +1042,26 @@ out:
  * the page allocator fallback scheme to ensure that aging of pages is balanced
  * across the zones.
  */
-static int balance_pgdat(pg_data_t *pgdat, int nr_pages, int order)
+static unsigned long balance_pgdat(pg_data_t *pgdat, unsigned long nr_pages,
+                                int order)
 {
-        int to_free = nr_pages;
+        unsigned long to_free = nr_pages;
         int all_zones_ok;
         int priority;
         int i;
-        int total_scanned, total_reclaimed;
+        unsigned long total_scanned;
+        unsigned long nr_reclaimed;
         struct reclaim_state *reclaim_state = current->reclaim_state;
-        struct scan_control sc;
+        struct scan_control sc = {
+                .gfp_mask = GFP_KERNEL,
+                .may_swap = 1,
+                .swap_cluster_max = nr_pages ? nr_pages : SWAP_CLUSTER_MAX,
+        };
 
 loop_again:
         total_scanned = 0;
-        total_reclaimed = 0;
-        sc.gfp_mask = GFP_KERNEL;
-        sc.may_writepage = !laptop_mode;
-        sc.may_swap = 1;
+        nr_reclaimed = 0;
+        sc.may_writepage = !laptop_mode,
         sc.nr_mapped = read_page_state(nr_mapped);
 
         inc_page_state(pageoutrun);
@@ -1624,15 +1142,11 @@ scan:
                         if (zone->prev_priority > priority)
                                 zone->prev_priority = priority;
                         sc.nr_scanned = 0;
-                        sc.nr_reclaimed = 0;
-                        sc.priority = priority;
-                        sc.swap_cluster_max = nr_pages? nr_pages : SWAP_CLUSTER_MAX;
-                        shrink_zone(zone, &sc);
+                        nr_reclaimed += shrink_zone(priority, zone, &sc);
                         reclaim_state->reclaimed_slab = 0;
                         nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
                                                 lru_pages);
-                        sc.nr_reclaimed += reclaim_state->reclaimed_slab;
-                        total_reclaimed += sc.nr_reclaimed;
+                        nr_reclaimed += reclaim_state->reclaimed_slab;
                         total_scanned += sc.nr_scanned;
                         if (zone->all_unreclaimable)
                                 continue;
@@ -1645,10 +1159,10 @@ scan:
                          * even in laptop mode
                          */
                         if (total_scanned > SWAP_CLUSTER_MAX * 2 &&
-                            total_scanned > total_reclaimed+total_reclaimed/2)
+                            total_scanned > nr_reclaimed + nr_reclaimed / 2)
                                 sc.may_writepage = 1;
                 }
-                if (nr_pages && to_free > total_reclaimed)
+                if (nr_pages && to_free > nr_reclaimed)
                         continue;       /* swsusp: need to do more work */
                 if (all_zones_ok)
                         break;          /* kswapd: all done */
@@ -1665,7 +1179,7 @@ scan:
                  * matches the direct reclaim path behaviour in terms of impact
                  * on zone->*_priority.
                  */
-                if ((total_reclaimed >= SWAP_CLUSTER_MAX) && (!nr_pages))
+                if ((nr_reclaimed >= SWAP_CLUSTER_MAX) && !nr_pages)
                         break;
         }
 out:
@@ -1679,7 +1193,7 @@ out:
                 goto loop_again;
         }
 
-        return total_reclaimed;
+        return nr_reclaimed;
 }
 
 /*
@@ -1779,24 +1293,31 @@ void wakeup_kswapd(struct zone *zone, int order)
  * Try to free `nr_pages' of memory, system-wide.  Returns the number of freed
  * pages.
  */
-int shrink_all_memory(int nr_pages)
+unsigned long shrink_all_memory(unsigned long nr_pages)
 {
         pg_data_t *pgdat;
-        int nr_to_free = nr_pages;
-        int ret = 0;
+        unsigned long nr_to_free = nr_pages;
+        unsigned long ret = 0;
+        unsigned retry = 2;
         struct reclaim_state reclaim_state = {
                 .reclaimed_slab = 0,
         };
 
         current->reclaim_state = &reclaim_state;
+repeat:
         for_each_pgdat(pgdat) {
-                int freed;
+                unsigned long freed;
+
                 freed = balance_pgdat(pgdat, nr_to_free, 0);
                 ret += freed;
                 nr_to_free -= freed;
-                if (nr_to_free <= 0)
+                if ((long)nr_to_free <= 0)
                         break;
         }
+        if (retry-- && ret < nr_pages) {
+                blk_congestion_wait(WRITE, HZ/5);
+                goto repeat;
+        }
         current->reclaim_state = NULL;
         return ret;
 }
@@ -1808,8 +1329,7 @@ int shrink_all_memory(int nr_pages)
    away, we get changed to run anywhere: as the first one comes back,
    restore their cpu bindings. */
 static int __devinit cpu_callback(struct notifier_block *nfb,
-                                  unsigned long action,
-                                  void *hcpu)
+                                  unsigned long action, void *hcpu)
 {
         pg_data_t *pgdat;
         cpumask_t mask;
@@ -1829,10 +1349,15 @@ static int __devinit cpu_callback(struct notifier_block *nfb,
 static int __init kswapd_init(void)
 {
         pg_data_t *pgdat;
+
         swap_setup();
-        for_each_pgdat(pgdat)
-                pgdat->kswapd
-                = find_task_by_pid(kernel_thread(kswapd, pgdat, CLONE_KERNEL));
+        for_each_pgdat(pgdat) {
+                pid_t pid;
+
+                pid = kernel_thread(kswapd, pgdat, CLONE_KERNEL);
+                BUG_ON(pid < 0);
+                pgdat->kswapd = find_task_by_pid(pid);
+        }
         total_memory = nr_free_pagecache_pages();
         hotcpu_notifier(cpu_callback, 0);
         return 0;
@@ -1874,46 +1399,24 @@ int zone_reclaim_interval __read_mostly = 30*HZ;
 /*
  * Try to free up some pages from this zone through reclaim.
  */
-int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
+static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 {
-        int nr_pages;
+        /* Minimum pages needed in order to stay on node */
+        const unsigned long nr_pages = 1 << order;
         struct task_struct *p = current;
         struct reclaim_state reclaim_state;
-        struct scan_control sc;
-        cpumask_t mask;
-        int node_id;
-
-        if (time_before(jiffies,
-                zone->last_unsuccessful_zone_reclaim + zone_reclaim_interval))
-                        return 0;
-
-        if (!(gfp_mask & __GFP_WAIT) ||
-                zone->all_unreclaimable ||
-                atomic_read(&zone->reclaim_in_progress) > 0 ||
-                (p->flags & PF_MEMALLOC))
-                        return 0;
-
-        node_id = zone->zone_pgdat->node_id;
-        mask = node_to_cpumask(node_id);
-        if (!cpus_empty(mask) && node_id != numa_node_id())
-                return 0;
-
-        sc.may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE);
-        sc.may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP);
-        sc.nr_scanned = 0;
-        sc.nr_reclaimed = 0;
-        sc.priority = ZONE_RECLAIM_PRIORITY + 1;
-        sc.nr_mapped = read_page_state(nr_mapped);
-        sc.gfp_mask = gfp_mask;
+        int priority;
+        unsigned long nr_reclaimed = 0;
+        struct scan_control sc = {
+                .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE),
+                .may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP),
+                .nr_mapped = read_page_state(nr_mapped),
+                .swap_cluster_max = max_t(unsigned long, nr_pages,
+                                        SWAP_CLUSTER_MAX),
+                .gfp_mask = gfp_mask,
+        };
 
         disable_swap_token();
-
-        nr_pages = 1 << order;
-        if (nr_pages > SWAP_CLUSTER_MAX)
-                sc.swap_cluster_max = nr_pages;
-        else
-                sc.swap_cluster_max = SWAP_CLUSTER_MAX;
-
         cond_resched();
         /*
          * We need to be able to allocate from the reserves for RECLAIM_SWAP
@@ -1928,17 +1431,20 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
          * Free memory by calling shrink zone with increasing priorities
          * until we have enough memory freed.
          */
+        priority = ZONE_RECLAIM_PRIORITY;
         do {
-                sc.priority--;
-                shrink_zone(zone, &sc);
+                nr_reclaimed += shrink_zone(priority, zone, &sc);
+                priority--;
+        } while (priority >= 0 && nr_reclaimed < nr_pages);
 
-        } while (sc.nr_reclaimed < nr_pages && sc.priority > 0);
-
-        if (sc.nr_reclaimed < nr_pages && (zone_reclaim_mode & RECLAIM_SLAB)) {
+        if (nr_reclaimed < nr_pages && (zone_reclaim_mode & RECLAIM_SLAB)) {
                 /*
-                 * shrink_slab does not currently allow us to determine
-                 * how many pages were freed in the zone. So we just
-                 * shake the slab and then go offnode for a single allocation.
+                 * shrink_slab() does not currently allow us to determine how
+                 * many pages were freed in this zone. So we just shake the slab
+                 * a bit and then go off node for this particular allocation
+                 * despite possibly having freed enough memory to allocate in
+                 * this zone.  If we freed local memory then the next
+                 * allocations will be local again.
                  *
                  * shrink_slab will free memory on all zones and may take
                  * a long time.
@@ -1949,10 +1455,54 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
         p->reclaim_state = NULL;
         current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE);
 
-        if (sc.nr_reclaimed == 0)
+        if (nr_reclaimed == 0) {
+                /*
+                 * We were unable to reclaim enough pages to stay on node.  We
+                 * now allow off node accesses for a certain time period before
+                 * trying again to reclaim pages from the local zone.
+                 */
                 zone->last_unsuccessful_zone_reclaim = jiffies;
+        }
 
-        return sc.nr_reclaimed >= nr_pages;
+        return nr_reclaimed >= nr_pages;
 }
-#endif
 
+int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
+{
+        cpumask_t mask;
+        int node_id;
+
+        /*
+         * Do not reclaim if there was a recent unsuccessful attempt at zone
+         * reclaim.  In that case we let allocations go off node for the
+         * zone_reclaim_interval.  Otherwise we would scan for each off-node
+         * page allocation.
+         */
+        if (time_before(jiffies,
+                zone->last_unsuccessful_zone_reclaim + zone_reclaim_interval))
+                        return 0;
+
+        /*
+         * Avoid concurrent zone reclaims, do not reclaim in a zone that does
+         * not have reclaimable pages and if we should not delay the allocation
+         * then do not scan.
+         */
+        if (!(gfp_mask & __GFP_WAIT) ||
+                zone->all_unreclaimable ||
+                atomic_read(&zone->reclaim_in_progress) > 0 ||
+                (current->flags & PF_MEMALLOC))
+                        return 0;
+
+        /*
+         * Only run zone reclaim on the local zone or on zones that do not
+         * have associated processors. This will favor the local processor
+         * over remote processors and spread off node memory allocations
+         * as wide as possible.
+         */
+        node_id = zone->zone_pgdat->node_id;
+        mask = node_to_cpumask(node_id);
+        if (!cpus_empty(mask) && node_id != numa_node_id())
+                return 0;
+        return __zone_reclaim(zone, gfp_mask, order);
+}
+#endif