mm: optimize compound_head() by avoiding a shared page flag
[sfrench/cifs-2.6.git] / mm / page_alloc.c
index 2c606cc922a50cc212b6f4abd6e8635356ebb99e..36d713e216e8d4dd22d42b3c1f72b570ff0965ea 100644 (file)
@@ -73,7 +73,9 @@ static void __free_pages_ok(struct page *page, unsigned int order);
  * don't need any ZONE_NORMAL reservation
  */
 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
+#ifdef CONFIG_ZONE_DMA
         256,
+#endif
 #ifdef CONFIG_ZONE_DMA32
         256,
 #endif
@@ -85,7 +87,9 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
 EXPORT_SYMBOL(totalram_pages);
 
 static char * const zone_names[MAX_NR_ZONES] = {
+#ifdef CONFIG_ZONE_DMA
         "DMA",
+#endif
 #ifdef CONFIG_ZONE_DMA32
         "DMA32",
 #endif
@@ -152,10 +156,8 @@ static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
 
 static int page_is_consistent(struct zone *zone, struct page *page)
 {
-#ifdef CONFIG_HOLES_IN_ZONE
-       if (!pfn_valid(page_to_pfn(page)))
+       if (!pfn_valid_within(page_to_pfn(page)))
                return 0;
-#endif
        if (zone != page_zone(page))
                return 0;
 
@@ -223,7 +225,7 @@ static void bad_page(struct page *page)
 
 static void free_compound_page(struct page *page)
 {
-       __free_pages_ok(page, (unsigned long)page[1].lru.prev);
+       __free_pages_ok(page, compound_order(page));
 }
 
 static void prep_compound_page(struct page *page, unsigned long order)
@@ -232,12 +234,13 @@ static void prep_compound_page(struct page *page, unsigned long order)
        int nr_pages = 1 << order;
 
        set_compound_page_dtor(page, free_compound_page);
-       page[1].lru.prev = (void *)order;
-       for (i = 0; i < nr_pages; i++) {
+       set_compound_order(page, order);
+       __SetPageHead(page);
+       for (i = 1; i < nr_pages; i++) {
                struct page *p = page + i;
 
-               __SetPageCompound(p);
-               set_page_private(p, (unsigned long)page);
+               __SetPageTail(p);
+               p->first_page = page;
        }
 }
 
@@ -246,16 +249,19 @@ static void destroy_compound_page(struct page *page, unsigned long order)
        int i;
        int nr_pages = 1 << order;
 
-       if (unlikely((unsigned long)page[1].lru.prev != order))
+       if (unlikely(compound_order(page) != order))
                bad_page(page);
 
-       for (i = 0; i < nr_pages; i++) {
+       if (unlikely(!PageHead(page)))
+                       bad_page(page);
+       __ClearPageHead(page);
+       for (i = 1; i < nr_pages; i++) {
                struct page *p = page + i;
 
-               if (unlikely(!PageCompound(p) |
-                               (page_private(p) != (unsigned long)page)))
+               if (unlikely(!PageTail(p) |
+                               (p->first_page != page)))
                        bad_page(page);
-               __ClearPageCompound(p);
+               __ClearPageTail(p);
        }
 }
 
@@ -342,10 +348,8 @@ __find_combined_index(unsigned long page_idx, unsigned int order)
 static inline int page_is_buddy(struct page *page, struct page *buddy,
                                                                int order)
 {
-#ifdef CONFIG_HOLES_IN_ZONE
-       if (!pfn_valid(page_to_pfn(buddy)))
+       if (!pfn_valid_within(page_to_pfn(buddy)))
                return 0;
-#endif
 
        if (page_zone_id(page) != page_zone_id(buddy))
                return 0;
@@ -395,7 +399,7 @@ static inline void __free_one_page(struct page *page,
        VM_BUG_ON(page_idx & (order_size - 1));
        VM_BUG_ON(bad_range(zone, page));
 
-       zone->free_pages += order_size;
+       __mod_zone_page_state(zone, NR_FREE_PAGES, order_size);
        while (order < MAX_ORDER-1) {
                unsigned long combined_idx;
                struct free_area *area;
@@ -429,13 +433,18 @@ static inline int free_pages_check(struct page *page)
                        1 << PG_private |
                        1 << PG_locked  |
                        1 << PG_active  |
-                       1 << PG_reclaim |
                        1 << PG_slab    |
                        1 << PG_swapcache |
                        1 << PG_writeback |
                        1 << PG_reserved |
                        1 << PG_buddy ))))
                bad_page(page);
+       /*
+        * PageReclaim == PageTail. It is only an error
+        * for PageReclaim to be set if PageCompound is clear.
+        */
+       if (unlikely(!PageCompound(page) && PageReclaim(page)))
+               bad_page(page);
        if (PageDirty(page))
                __ClearPageDirty(page);
        /*
@@ -596,7 +605,7 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
 
        page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
                        1 << PG_referenced | 1 << PG_arch_1 |
-                       1 << PG_checked | 1 << PG_mappedtodisk);
+                       1 << PG_owner_priv_1 | 1 << PG_mappedtodisk);
        set_page_private(page, 0);
        set_page_refcounted(page);
 
@@ -631,7 +640,7 @@ static struct page *__rmqueue(struct zone *zone, unsigned int order)
                list_del(&page->lru);
                rmv_page_order(page);
                area->nr_free--;
-               zone->free_pages -= 1UL << order;
+               __mod_zone_page_state(zone, NR_FREE_PAGES, - (1UL << order));
                expand(zone, page, order, current_order, area);
                return page;
        }
@@ -660,6 +669,26 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
        return i;
 }
 
+#if MAX_NUMNODES > 1
+int nr_node_ids __read_mostly = MAX_NUMNODES;
+EXPORT_SYMBOL(nr_node_ids);
+
+/*
+ * Figure out the number of possible node ids.
+ */
+static void __init setup_nr_node_ids(void)
+{
+       unsigned int node;
+       unsigned int highest = 0;
+
+       for_each_node_mask(node, node_possible_map)
+               highest = node;
+       nr_node_ids = highest + 1;
+}
+#else
+static void __init setup_nr_node_ids(void) {}
+#endif
+
 #ifdef CONFIG_NUMA
 /*
  * Called from the slab reaper to drain pagesets on a particular node that
@@ -989,7 +1018,8 @@ int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
                      int classzone_idx, int alloc_flags)
 {
        /* free_pages my go negative - that's OK */
-       long min = mark, free_pages = z->free_pages - (1 << order) + 1;
+       long min = mark;
+       long free_pages = zone_page_state(z, NR_FREE_PAGES) - (1 << order) + 1;
        int o;
 
        if (alloc_flags & ALLOC_HIGH)
@@ -1439,35 +1469,6 @@ fastcall void free_pages(unsigned long addr, unsigned int order)
 
 EXPORT_SYMBOL(free_pages);
 
-/*
- * Total amount of free (allocatable) RAM:
- */
-unsigned int nr_free_pages(void)
-{
-       unsigned int sum = 0;
-       struct zone *zone;
-
-       for_each_zone(zone)
-               sum += zone->free_pages;
-
-       return sum;
-}
-
-EXPORT_SYMBOL(nr_free_pages);
-
-#ifdef CONFIG_NUMA
-unsigned int nr_free_pages_pgdat(pg_data_t *pgdat)
-{
-       unsigned int sum = 0;
-       enum zone_type i;
-
-       for (i = 0; i < MAX_NR_ZONES; i++)
-               sum += pgdat->node_zones[i].free_pages;
-
-       return sum;
-}
-#endif
-
 static unsigned int nr_free_zone_pages(int offset)
 {
        /* Just pick one node, since fallback list is circular */
@@ -1514,7 +1515,7 @@ void si_meminfo(struct sysinfo *val)
 {
        val->totalram = totalram_pages;
        val->sharedram = 0;
-       val->freeram = nr_free_pages();
+       val->freeram = global_page_state(NR_FREE_PAGES);
        val->bufferram = nr_blockdev_pages();
        val->totalhigh = totalhigh_pages;
        val->freehigh = nr_free_highpages();
@@ -1529,10 +1530,11 @@ void si_meminfo_node(struct sysinfo *val, int nid)
        pg_data_t *pgdat = NODE_DATA(nid);
 
        val->totalram = pgdat->node_present_pages;
-       val->freeram = nr_free_pages_pgdat(pgdat);
+       val->freeram = node_page_state(nid, NR_FREE_PAGES);
 #ifdef CONFIG_HIGHMEM
        val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
-       val->freehigh = pgdat->node_zones[ZONE_HIGHMEM].free_pages;
+       val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
+                       NR_FREE_PAGES);
 #else
        val->totalhigh = 0;
        val->freehigh = 0;
@@ -1551,9 +1553,6 @@ void si_meminfo_node(struct sysinfo *val, int nid)
 void show_free_areas(void)
 {
        int cpu;
-       unsigned long active;
-       unsigned long inactive;
-       unsigned long free;
        struct zone *zone;
 
        for_each_zone(zone) {
@@ -1577,20 +1576,19 @@ void show_free_areas(void)
                }
        }
 
-       get_zone_counts(&active, &inactive, &free);
-
-       printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu "
-               "unstable:%lu free:%u slab:%lu mapped:%lu pagetables:%lu\n",
-               active,
-               inactive,
+       printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu\n"
+               " free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
+               global_page_state(NR_ACTIVE),
+               global_page_state(NR_INACTIVE),
                global_page_state(NR_FILE_DIRTY),
                global_page_state(NR_WRITEBACK),
                global_page_state(NR_UNSTABLE_NFS),
-               nr_free_pages(),
+               global_page_state(NR_FREE_PAGES),
                global_page_state(NR_SLAB_RECLAIMABLE) +
                        global_page_state(NR_SLAB_UNRECLAIMABLE),
                global_page_state(NR_FILE_MAPPED),
-               global_page_state(NR_PAGETABLE));
+               global_page_state(NR_PAGETABLE),
+               global_page_state(NR_BOUNCE));
 
        for_each_zone(zone) {
                int i;
@@ -1611,12 +1609,12 @@ void show_free_areas(void)
                        " all_unreclaimable? %s"
                        "\n",
                        zone->name,
-                       K(zone->free_pages),
+                       K(zone_page_state(zone, NR_FREE_PAGES)),
                        K(zone->pages_min),
                        K(zone->pages_low),
                        K(zone->pages_high),
-                       K(zone->nr_active),
-                       K(zone->nr_inactive),
+                       K(zone_page_state(zone, NR_ACTIVE)),
+                       K(zone_page_state(zone, NR_INACTIVE)),
                        K(zone->present_pages),
                        zone->pages_scanned,
                        (zone->all_unreclaimable ? "yes" : "no")
@@ -2650,11 +2648,11 @@ static void __meminit free_area_init_core(struct pglist_data *pgdat,
                                "  %s zone: %lu pages exceeds realsize %lu\n",
                                zone_names[j], memmap_pages, realsize);
 
-               /* Account for reserved DMA pages */
-               if (j == ZONE_DMA && realsize > dma_reserve) {
+               /* Account for reserved pages */
+               if (j == 0 && realsize > dma_reserve) {
                        realsize -= dma_reserve;
-                       printk(KERN_DEBUG "  DMA zone: %lu pages reserved\n",
-                                                               dma_reserve);
+                       printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
+                                       zone_names[0], dma_reserve);
                }
 
                if (!is_highmem_idx(j))
@@ -2674,7 +2672,6 @@ static void __meminit free_area_init_core(struct pglist_data *pgdat,
                spin_lock_init(&zone->lru_lock);
                zone_seqlock_init(zone);
                zone->zone_pgdat = pgdat;
-               zone->free_pages = 0;
 
                zone->prev_priority = DEF_PRIORITY;
 
@@ -2683,8 +2680,6 @@ static void __meminit free_area_init_core(struct pglist_data *pgdat,
                INIT_LIST_HEAD(&zone->inactive_list);
                zone->nr_scan_active = 0;
                zone->nr_scan_inactive = 0;
-               zone->nr_active = 0;
-               zone->nr_inactive = 0;
                zap_zone_vm_stats(zone);
                atomic_set(&zone->reclaim_in_progress, 0);
                if (!size)
@@ -2876,20 +2871,23 @@ static void __init sort_node_map(void)
                        cmp_node_active_region, NULL);
 }
 
-/* Find the lowest pfn for a node. This depends on a sorted early_node_map */
+/* Find the lowest pfn for a node */
 unsigned long __init find_min_pfn_for_node(unsigned long nid)
 {
        int i;
-
-       /* Regions in the early_node_map can be in any order */
-       sort_node_map();
+       unsigned long min_pfn = ULONG_MAX;
 
        /* Assuming a sorted map, the first range found has the starting pfn */
        for_each_active_range_index_in_nid(i, nid)
-               return early_node_map[i].start_pfn;
+               min_pfn = min(min_pfn, early_node_map[i].start_pfn);
 
-       printk(KERN_WARNING "Could not find start_pfn for node %lu\n", nid);
-       return 0;
+       if (min_pfn == ULONG_MAX) {
+               printk(KERN_WARNING
+                       "Could not find start_pfn for node %lu\n", nid);
+               return 0;
+       }
+
+       return min_pfn;
 }
 
 /**
@@ -2938,6 +2936,9 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
        unsigned long nid;
        enum zone_type i;
 
+       /* Sort early_node_map as initialisation assumes it is sorted */
+       sort_node_map();
+
        /* Record where the zone boundaries are */
        memset(arch_zone_lowest_possible_pfn, 0,
                                sizeof(arch_zone_lowest_possible_pfn));
@@ -2968,6 +2969,7 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
                                                early_node_map[i].end_pfn);
 
        /* Initialise every node */
+       setup_nr_node_ids();
        for_each_online_node(nid) {
                pg_data_t *pgdat = NODE_DATA(nid);
                free_area_init_node(nid, pgdat, NULL,
@@ -3206,7 +3208,8 @@ int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
        struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
 {
        proc_dointvec(table, write, file, buffer, length, ppos);
-       setup_per_zone_pages_min();
+       if (write)
+               setup_per_zone_pages_min();
        return 0;
 }
 
@@ -3394,18 +3397,4 @@ EXPORT_SYMBOL(pfn_to_page);
 EXPORT_SYMBOL(page_to_pfn);
 #endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
 
-#if MAX_NUMNODES > 1
-/*
- * Find the highest possible node id.
- */
-int highest_possible_node_id(void)
-{
-       unsigned int node;
-       unsigned int highest = 0;
 
-       for_each_node_mask(node, node_possible_map)
-               highest = node;
-       return highest;
-}
-EXPORT_SYMBOL(highest_possible_node_id);
-#endif