Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

[safe/jmp/linux-2.6] / mm / vmstat.c

diff --git a/mm/vmstat.c b/mm/vmstat.c
index d3e0fa1..7759941 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -16,6 +16,7 @@
 #include <linux/cpu.h>
 #include <linux/vmstat.h>
 #include <linux/sched.h>
+#include <linux/math64.h>
 
 #ifdef CONFIG_VM_EVENT_COUNTERS
 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
@@ -420,6 +421,42 @@ static void fill_contig_page_info(struct zone *zone,
                                                (order - suitable_order);
        }
 }
+
+/*
+ * A fragmentation index only makes sense if an allocation of a requested
+ * size would fail. If that is true, the fragmentation index indicates
+ * whether external fragmentation or a lack of memory was the problem.
+ * The value can be used to determine if page reclaim or compaction
+ * should be used
+ */
+static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
+{
+       unsigned long requested = 1UL << order;
+
+       if (!info->free_blocks_total)
+               return 0;
+
+       /* Fragmentation index only makes sense when a request would fail */
+       if (info->free_blocks_suitable)
+               return -1000;
+
+       /*
+        * Index is between 0 and 1 so return within 3 decimal places
+        *
+        * 0 => allocation would fail due to lack of memory
+        * 1 => allocation would fail due to fragmentation
+        */
+       return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
+}
+
+/* Same as __fragmentation index but allocs contig_page_info on stack */
+int fragmentation_index(struct zone *zone, unsigned int order)
+{
+       struct contig_page_info info;
+
+       fill_contig_page_info(zone, order, &info);
+       return __fragmentation_index(order, &info);
+}
 #endif
 
 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
@@ -738,6 +775,16 @@ static const char * const vmstat_text[] = {
        "allocstall",
 
        "pgrotated",
+
+#ifdef CONFIG_COMPACTION
+       "compact_blocks_moved",
+       "compact_pages_moved",
+       "compact_pagemigrate_failed",
+       "compact_stall",
+       "compact_fail",
+       "compact_success",
+#endif
+
 #ifdef CONFIG_HUGETLB_PAGE
        "htlb_buddy_alloc_success",
        "htlb_buddy_alloc_fail",
@@ -1087,6 +1134,58 @@ static const struct file_operations unusable_file_ops = {
        .release        = seq_release,
 };
 
+static void extfrag_show_print(struct seq_file *m,
+                                       pg_data_t *pgdat, struct zone *zone)
+{
+       unsigned int order;
+       int index;
+
+       /* Alloc on stack as interrupts are disabled for zone walk */
+       struct contig_page_info info;
+
+       seq_printf(m, "Node %d, zone %8s ",
+                               pgdat->node_id,
+                               zone->name);
+       for (order = 0; order < MAX_ORDER; ++order) {
+               fill_contig_page_info(zone, order, &info);
+               index = __fragmentation_index(order, &info);
+               seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
+       }
+
+       seq_putc(m, '\n');
+}
+
+/*
+ * Display fragmentation index for orders that allocations would fail for
+ */
+static int extfrag_show(struct seq_file *m, void *arg)
+{
+       pg_data_t *pgdat = (pg_data_t *)arg;
+
+       walk_zones_in_node(m, pgdat, extfrag_show_print);
+
+       return 0;
+}
+
+static const struct seq_operations extfrag_op = {
+       .start  = frag_start,
+       .next   = frag_next,
+       .stop   = frag_stop,
+       .show   = extfrag_show,
+};
+
+static int extfrag_open(struct inode *inode, struct file *file)
+{
+       return seq_open(file, &extfrag_op);
+}
+
+static const struct file_operations extfrag_file_ops = {
+       .open           = extfrag_open,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = seq_release,
+};
+
 static int __init extfrag_debug_init(void)
 {
        extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
@@ -1097,6 +1196,10 @@ static int __init extfrag_debug_init(void)
                        extfrag_debug_root, NULL, &unusable_file_ops))
                return -ENOMEM;
 
+       if (!debugfs_create_file("extfrag_index", 0444,
+                       extfrag_debug_root, NULL, &extfrag_file_ops))
+               return -ENOMEM;
+
        return 0;
 }