diff options
| -rw-r--r-- | mm/vmstat.c | 150 |
1 files changed, 149 insertions, 1 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c index fa12ea3051f..d3e0fa169f0 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -379,7 +379,50 @@ void zone_statistics(struct zone *preferred_zone, struct zone *z) } #endif -#ifdef CONFIG_PROC_FS +#ifdef CONFIG_COMPACTION +struct contig_page_info { + unsigned long free_pages; + unsigned long free_blocks_total; + unsigned long free_blocks_suitable; +}; + +/* + * Calculate the number of free pages in a zone, how many contiguous + * pages are free and how many are large enough to satisfy an allocation of + * the target size. Note that this function makes no attempt to estimate + * how many suitable free blocks there *might* be if MOVABLE pages were + * migrated. Calculating that is possible, but expensive and can be + * figured out from userspace + */ +static void fill_contig_page_info(struct zone *zone, + unsigned int suitable_order, + struct contig_page_info *info) +{ + unsigned int order; + + info->free_pages = 0; + info->free_blocks_total = 0; + info->free_blocks_suitable = 0; + + for (order = 0; order < MAX_ORDER; order++) { + unsigned long blocks; + + /* Count number of free blocks */ + blocks = zone->free_area[order].nr_free; + info->free_blocks_total += blocks; + + /* Count free base pages */ + info->free_pages += blocks << order; + + /* Count the suitable free blocks */ + if (order >= suitable_order) + info->free_blocks_suitable += blocks << + (order - suitable_order); + } +} +#endif + +#if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION) #include <linux/proc_fs.h> #include <linux/seq_file.h> @@ -432,7 +475,9 @@ static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat, spin_unlock_irqrestore(&zone->lock, flags); } } +#endif +#ifdef CONFIG_PROC_FS static void frag_show_print(struct seq_file *m, pg_data_t *pgdat, struct zone *zone) { @@ -954,3 +999,106 @@ static int __init setup_vmstat(void) return 0; } module_init(setup_vmstat) + +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION) +#include <linux/debugfs.h> + +static struct dentry *extfrag_debug_root; + +/* + * Return an index indicating how much of the available free memory is + * unusable for an allocation of the requested size. + */ +static int unusable_free_index(unsigned int order, + struct contig_page_info *info) +{ + /* No free memory is interpreted as all free memory is unusable */ + if (info->free_pages == 0) + return 1000; + + /* + * Index should be a value between 0 and 1. Return a value to 3 + * decimal places. + * + * 0 => no fragmentation + * 1 => high fragmentation + */ + return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages); + +} + +static void unusable_show_print(struct seq_file *m, + pg_data_t *pgdat, struct zone *zone) +{ + unsigned int order; + int index; + 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 = unusable_free_index(order, &info); + seq_printf(m, "%d.%03d ", index / 1000, index % 1000); + } + + seq_putc(m, '\n'); +} + +/* + * Display unusable free space index + * + * The unusable free space index measures how much of the available free + * memory cannot be used to satisfy an allocation of a given size and is a + * value between 0 and 1. The higher the value, the more of free memory is + * unusable and by implication, the worse the external fragmentation is. This + * can be expressed as a percentage by multiplying by 100. + */ +static int unusable_show(struct seq_file *m, void *arg) +{ + pg_data_t *pgdat = (pg_data_t *)arg; + + /* check memoryless node */ + if (!node_state(pgdat->node_id, N_HIGH_MEMORY)) + return 0; + + walk_zones_in_node(m, pgdat, unusable_show_print); + + return 0; +} + +static const struct seq_operations unusable_op = { + .start = frag_start, + .next = frag_next, + .stop = frag_stop, + .show = unusable_show, +}; + +static int unusable_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &unusable_op); +} + +static const struct file_operations unusable_file_ops = { + .open = unusable_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); + if (!extfrag_debug_root) + return -ENOMEM; + + if (!debugfs_create_file("unusable_index", 0444, + extfrag_debug_root, NULL, &unusable_file_ops)) + return -ENOMEM; + + return 0; +} + +module_init(extfrag_debug_init); +#endif |