diff options
| -rw-r--r-- | include/linux/mmzone.h | 41 | ||||
| -rw-r--r-- | mm/bootmem.c | 21 | ||||
| -rw-r--r-- | mm/memory_hotplug.c | 10 | ||||
| -rw-r--r-- | mm/nobootmem.c | 22 | ||||
| -rw-r--r-- | mm/page_alloc.c | 44 | ||||
| -rw-r--r-- | mm/vmstat.c | 6 |
6 files changed, 121 insertions, 23 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 0c0b1d608a6..cd55dad56aa 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -460,17 +460,44 @@ struct zone { unsigned long zone_start_pfn; /* - * zone_start_pfn, spanned_pages and present_pages are all - * protected by span_seqlock. It is a seqlock because it has - * to be read outside of zone->lock, and it is done in the main - * allocator path. But, it is written quite infrequently. + * spanned_pages is the total pages spanned by the zone, including + * holes, which is calculated as: + * spanned_pages = zone_end_pfn - zone_start_pfn; * - * The lock is declared along with zone->lock because it is + * present_pages is physical pages existing within the zone, which + * is calculated as: + * present_pages = spanned_pages - absent_pages(pags in holes); + * + * managed_pages is present pages managed by the buddy system, which + * is calculated as (reserved_pages includes pages allocated by the + * bootmem allocator): + * managed_pages = present_pages - reserved_pages; + * + * So present_pages may be used by memory hotplug or memory power + * management logic to figure out unmanaged pages by checking + * (present_pages - managed_pages). And managed_pages should be used + * by page allocator and vm scanner to calculate all kinds of watermarks + * and thresholds. + * + * Locking rules: + * + * zone_start_pfn and spanned_pages are protected by span_seqlock. + * It is a seqlock because it has to be read outside of zone->lock, + * and it is done in the main allocator path. But, it is written + * quite infrequently. + * + * The span_seq lock is declared along with zone->lock because it is * frequently read in proximity to zone->lock. It's good to * give them a chance of being in the same cacheline. + * + * Write access to present_pages and managed_pages at runtime should + * be protected by lock_memory_hotplug()/unlock_memory_hotplug(). + * Any reader who can't tolerant drift of present_pages and + * managed_pages should hold memory hotplug lock to get a stable value. */ - unsigned long spanned_pages; /* total size, including holes */ - unsigned long present_pages; /* amount of memory (excluding holes) */ + unsigned long spanned_pages; + unsigned long present_pages; + unsigned long managed_pages; /* * rarely used fields: diff --git a/mm/bootmem.c b/mm/bootmem.c index 26d057a8b55..19262ac05dd 100644 --- a/mm/bootmem.c +++ b/mm/bootmem.c @@ -229,6 +229,22 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) return count; } +static void reset_node_lowmem_managed_pages(pg_data_t *pgdat) +{ + struct zone *z; + + /* + * In free_area_init_core(), highmem zone's managed_pages is set to + * present_pages, and bootmem allocator doesn't allocate from highmem + * zones. So there's no need to recalculate managed_pages because all + * highmem pages will be managed by the buddy system. Here highmem + * zone also includes highmem movable zone. + */ + for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) + if (!is_highmem(z)) + z->managed_pages = 0; +} + /** * free_all_bootmem_node - release a node's free pages to the buddy allocator * @pgdat: node to be released @@ -238,6 +254,7 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) unsigned long __init free_all_bootmem_node(pg_data_t *pgdat) { register_page_bootmem_info_node(pgdat); + reset_node_lowmem_managed_pages(pgdat); return free_all_bootmem_core(pgdat->bdata); } @@ -250,6 +267,10 @@ unsigned long __init free_all_bootmem(void) { unsigned long total_pages = 0; bootmem_data_t *bdata; + struct pglist_data *pgdat; + + for_each_online_pgdat(pgdat) + reset_node_lowmem_managed_pages(pgdat); list_for_each_entry(bdata, &bdata_list, list) total_pages += free_all_bootmem_core(bdata); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index c6cd8b51542..b7c93ca896d 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -106,6 +106,7 @@ static void get_page_bootmem(unsigned long info, struct page *page, void __ref put_page_bootmem(struct page *page) { unsigned long type; + static DEFINE_MUTEX(ppb_lock); type = (unsigned long) page->lru.next; BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || @@ -115,7 +116,14 @@ void __ref put_page_bootmem(struct page *page) ClearPagePrivate(page); set_page_private(page, 0); INIT_LIST_HEAD(&page->lru); + + /* + * Please refer to comment for __free_pages_bootmem() + * for why we serialize here. + */ + mutex_lock(&ppb_lock); __free_pages_bootmem(page, 0); + mutex_unlock(&ppb_lock); } } @@ -748,6 +756,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ return ret; } + zone->managed_pages += onlined_pages; zone->present_pages += onlined_pages; zone->zone_pgdat->node_present_pages += onlined_pages; if (onlined_pages) { @@ -1321,6 +1330,7 @@ repeat: /* reset pagetype flags and makes migrate type to be MOVABLE */ undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); /* removal success */ + zone->managed_pages -= offlined_pages; zone->present_pages -= offlined_pages; zone->zone_pgdat->node_present_pages -= offlined_pages; totalram_pages -= offlined_pages; diff --git a/mm/nobootmem.c b/mm/nobootmem.c index bd82f6b3141..b8294fc03df 100644 --- a/mm/nobootmem.c +++ b/mm/nobootmem.c @@ -137,6 +137,22 @@ unsigned long __init free_low_memory_core_early(int nodeid) return count; } +static void reset_node_lowmem_managed_pages(pg_data_t *pgdat) +{ + struct zone *z; + + /* + * In free_area_init_core(), highmem zone's managed_pages is set to + * present_pages, and bootmem allocator doesn't allocate from highmem + * zones. So there's no need to recalculate managed_pages because all + * highmem pages will be managed by the buddy system. Here highmem + * zone also includes highmem movable zone. + */ + for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) + if (!is_highmem(z)) + z->managed_pages = 0; +} + /** * free_all_bootmem_node - release a node's free pages to the buddy allocator * @pgdat: node to be released @@ -146,6 +162,7 @@ unsigned long __init free_low_memory_core_early(int nodeid) unsigned long __init free_all_bootmem_node(pg_data_t *pgdat) { register_page_bootmem_info_node(pgdat); + reset_node_lowmem_managed_pages(pgdat); /* free_low_memory_core_early(MAX_NUMNODES) will be called later */ return 0; @@ -158,6 +175,11 @@ unsigned long __init free_all_bootmem_node(pg_data_t *pgdat) */ unsigned long __init free_all_bootmem(void) { + struct pglist_data *pgdat; + + for_each_online_pgdat(pgdat) + reset_node_lowmem_managed_pages(pgdat); + /* * We need to use MAX_NUMNODES instead of NODE_DATA(0)->node_id * because in some case like Node0 doesn't have RAM installed diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2bf0d43d646..0b6a6d04300 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -735,6 +735,13 @@ static void __free_pages_ok(struct page *page, unsigned int order) local_irq_restore(flags); } +/* + * Read access to zone->managed_pages is safe because it's unsigned long, + * but we still need to serialize writers. Currently all callers of + * __free_pages_bootmem() except put_page_bootmem() should only be used + * at boot time. So for shorter boot time, we shift the burden to + * put_page_bootmem() to serialize writers. + */ void __meminit __free_pages_bootmem(struct page *page, unsigned int order) { unsigned int nr_pages = 1 << order; @@ -750,6 +757,7 @@ void __meminit __free_pages_bootmem(struct page *page, unsigned int order) set_page_count(p, 0); } + page_zone(page)->managed_pages += 1 << order; set_page_refcounted(page); __free_pages(page, order); } @@ -2984,6 +2992,7 @@ void show_free_areas(unsigned int filter) " isolated(anon):%lukB" " isolated(file):%lukB" " present:%lukB" + " managed:%lukB" " mlocked:%lukB" " dirty:%lukB" " writeback:%lukB" @@ -3013,6 +3022,7 @@ void show_free_areas(unsigned int filter) K(zone_page_state(zone, NR_ISOLATED_ANON)), K(zone_page_state(zone, NR_ISOLATED_FILE)), K(zone->present_pages), + K(zone->managed_pages), K(zone_page_state(zone, NR_MLOCK)), K(zone_page_state(zone, NR_FILE_DIRTY)), K(zone_page_state(zone, NR_WRITEBACK)), @@ -4502,48 +4512,54 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, for (j = 0; j < MAX_NR_ZONES; j++) { struct zone *zone = pgdat->node_zones + j; - unsigned long size, realsize, memmap_pages; + unsigned long size, realsize, freesize, memmap_pages; size = zone_spanned_pages_in_node(nid, j, zones_size); - realsize = size - zone_absent_pages_in_node(nid, j, + realsize = freesize = size - zone_absent_pages_in_node(nid, j, zholes_size); /* - * Adjust realsize so that it accounts for how much memory + * Adjust freesize so that it accounts for how much memory * is used by this zone for memmap. This affects the watermark * and per-cpu initialisations */ memmap_pages = PAGE_ALIGN(size * sizeof(struct page)) >> PAGE_SHIFT; - if (realsize >= memmap_pages) { - realsize -= memmap_pages; + if (freesize >= memmap_pages) { + freesize -= memmap_pages; if (memmap_pages) printk(KERN_DEBUG " %s zone: %lu pages used for memmap\n", zone_names[j], memmap_pages); } else printk(KERN_WARNING - " %s zone: %lu pages exceeds realsize %lu\n", - zone_names[j], memmap_pages, realsize); + " %s zone: %lu pages exceeds freesize %lu\n", + zone_names[j], memmap_pages, freesize); /* Account for reserved pages */ - if (j == 0 && realsize > dma_reserve) { - realsize -= dma_reserve; + if (j == 0 && freesize > dma_reserve) { + freesize -= dma_reserve; printk(KERN_DEBUG " %s zone: %lu pages reserved\n", zone_names[0], dma_reserve); } if (!is_highmem_idx(j)) - nr_kernel_pages += realsize; - nr_all_pages += realsize; + nr_kernel_pages += freesize; + nr_all_pages += freesize; zone->spanned_pages = size; - zone->present_pages = realsize; + zone->present_pages = freesize; + /* + * Set an approximate value for lowmem here, it will be adjusted + * when the bootmem allocator frees pages into the buddy system. + * And all highmem pages will be managed by the buddy system. + */ + zone->managed_pages = is_highmem_idx(j) ? realsize : freesize; #ifdef CONFIG_NUMA zone->node = nid; - zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio) + zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio) / 100; - zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100; + zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100; #endif zone->name = zone_names[j]; spin_lock_init(&zone->lock); diff --git a/mm/vmstat.c b/mm/vmstat.c index 9a4a522c0b0..df14808f0a3 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -994,14 +994,16 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, "\n high %lu" "\n scanned %lu" "\n spanned %lu" - "\n present %lu", + "\n present %lu" + "\n managed %lu", zone_page_state(zone, NR_FREE_PAGES), min_wmark_pages(zone), low_wmark_pages(zone), high_wmark_pages(zone), zone->pages_scanned, zone->spanned_pages, - zone->present_pages); + zone->present_pages, + zone->managed_pages); for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) seq_printf(m, "\n %-12s %lu", vmstat_text[i], |