diff options
Diffstat (limited to 'mm/memory_hotplug.c')
| -rw-r--r-- | mm/memory_hotplug.c | 312 |
1 files changed, 283 insertions, 29 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index df9d554bea3..091b9c6c252 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -23,6 +23,9 @@ #include <linux/vmalloc.h> #include <linux/ioport.h> #include <linux/cpuset.h> +#include <linux/delay.h> +#include <linux/migrate.h> +#include <linux/page-isolation.h> #include <asm/tlbflush.h> @@ -161,14 +164,27 @@ static void grow_pgdat_span(struct pglist_data *pgdat, pgdat->node_start_pfn; } -int online_pages(unsigned long pfn, unsigned long nr_pages) +static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, + void *arg) { unsigned long i; + unsigned long onlined_pages = *(unsigned long *)arg; + struct page *page; + if (PageReserved(pfn_to_page(start_pfn))) + for (i = 0; i < nr_pages; i++) { + page = pfn_to_page(start_pfn + i); + online_page(page); + onlined_pages++; + } + *(unsigned long *)arg = onlined_pages; + return 0; +} + + +int online_pages(unsigned long pfn, unsigned long nr_pages) +{ unsigned long flags; unsigned long onlined_pages = 0; - struct resource res; - u64 section_end; - unsigned long start_pfn; struct zone *zone; int need_zonelists_rebuild = 0; @@ -191,32 +207,16 @@ int online_pages(unsigned long pfn, unsigned long nr_pages) if (!populated_zone(zone)) need_zonelists_rebuild = 1; - res.start = (u64)pfn << PAGE_SHIFT; - res.end = res.start + ((u64)nr_pages << PAGE_SHIFT) - 1; - res.flags = IORESOURCE_MEM; /* we just need system ram */ - section_end = res.end; - - while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) { - start_pfn = (unsigned long)(res.start >> PAGE_SHIFT); - nr_pages = (unsigned long) - ((res.end + 1 - res.start) >> PAGE_SHIFT); - - if (PageReserved(pfn_to_page(start_pfn))) { - /* this region's page is not onlined now */ - for (i = 0; i < nr_pages; i++) { - struct page *page = pfn_to_page(start_pfn + i); - online_page(page); - onlined_pages++; - } - } - - res.start = res.end + 1; - res.end = section_end; - } + walk_memory_resource(pfn, nr_pages, &onlined_pages, + online_pages_range); zone->present_pages += onlined_pages; zone->zone_pgdat->node_present_pages += onlined_pages; setup_per_zone_pages_min(); + if (onlined_pages) { + kswapd_run(zone_to_nid(zone)); + node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); + } if (need_zonelists_rebuild) build_all_zonelists(); @@ -271,9 +271,6 @@ int add_memory(int nid, u64 start, u64 size) if (!pgdat) return -ENOMEM; new_pgdat = 1; - ret = kswapd_run(nid); - if (ret) - goto error; } /* call arch's memory hotadd */ @@ -308,3 +305,260 @@ error: return ret; } EXPORT_SYMBOL_GPL(add_memory); + +#ifdef CONFIG_MEMORY_HOTREMOVE +/* + * Confirm all pages in a range [start, end) is belongs to the same zone. + */ +static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) +{ + unsigned long pfn; + struct zone *zone = NULL; + struct page *page; + int i; + for (pfn = start_pfn; + pfn < end_pfn; + pfn += MAX_ORDER_NR_PAGES) { + i = 0; + /* This is just a CONFIG_HOLES_IN_ZONE check.*/ + while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) + i++; + if (i == MAX_ORDER_NR_PAGES) + continue; + page = pfn_to_page(pfn + i); + if (zone && page_zone(page) != zone) + return 0; + zone = page_zone(page); + } + return 1; +} + +/* + * Scanning pfn is much easier than scanning lru list. + * Scan pfn from start to end and Find LRU page. + */ +int scan_lru_pages(unsigned long start, unsigned long end) +{ + unsigned long pfn; + struct page *page; + for (pfn = start; pfn < end; pfn++) { + if (pfn_valid(pfn)) { + page = pfn_to_page(pfn); + if (PageLRU(page)) + return pfn; + } + } + return 0; +} + +static struct page * +hotremove_migrate_alloc(struct page *page, + unsigned long private, + int **x) +{ + /* This should be improoooooved!! */ + return alloc_page(GFP_HIGHUSER_PAGECACHE); +} + + +#define NR_OFFLINE_AT_ONCE_PAGES (256) +static int +do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) +{ + unsigned long pfn; + struct page *page; + int move_pages = NR_OFFLINE_AT_ONCE_PAGES; + int not_managed = 0; + int ret = 0; + LIST_HEAD(source); + + for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { + if (!pfn_valid(pfn)) + continue; + page = pfn_to_page(pfn); + if (!page_count(page)) + continue; + /* + * We can skip free pages. And we can only deal with pages on + * LRU. + */ + ret = isolate_lru_page(page, &source); + if (!ret) { /* Success */ + move_pages--; + } else { + /* Becasue we don't have big zone->lock. we should + check this again here. */ + if (page_count(page)) + not_managed++; +#ifdef CONFIG_DEBUG_VM + printk(KERN_INFO "removing from LRU failed" + " %lx/%d/%lx\n", + pfn, page_count(page), page->flags); +#endif + } + } + ret = -EBUSY; + if (not_managed) { + if (!list_empty(&source)) + putback_lru_pages(&source); + goto out; + } + ret = 0; + if (list_empty(&source)) + goto out; + /* this function returns # of failed pages */ + ret = migrate_pages(&source, hotremove_migrate_alloc, 0); + +out: + return ret; +} + +/* + * remove from free_area[] and mark all as Reserved. + */ +static int +offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, + void *data) +{ + __offline_isolated_pages(start, start + nr_pages); + return 0; +} + +static void +offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) +{ + walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL, + offline_isolated_pages_cb); +} + +/* + * Check all pages in range, recoreded as memory resource, are isolated. + */ +static int +check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, + void *data) +{ + int ret; + long offlined = *(long *)data; + ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); + offlined = nr_pages; + if (!ret) + *(long *)data += offlined; + return ret; +} + +static long +check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) +{ + long offlined = 0; + int ret; + + ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined, + check_pages_isolated_cb); + if (ret < 0) + offlined = (long)ret; + return offlined; +} + +extern void drain_all_local_pages(void); + +int offline_pages(unsigned long start_pfn, + unsigned long end_pfn, unsigned long timeout) +{ + unsigned long pfn, nr_pages, expire; + long offlined_pages; + int ret, drain, retry_max; + struct zone *zone; + + BUG_ON(start_pfn >= end_pfn); + /* at least, alignment against pageblock is necessary */ + if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) + return -EINVAL; + if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) + return -EINVAL; + /* This makes hotplug much easier...and readable. + we assume this for now. .*/ + if (!test_pages_in_a_zone(start_pfn, end_pfn)) + return -EINVAL; + /* set above range as isolated */ + ret = start_isolate_page_range(start_pfn, end_pfn); + if (ret) + return ret; + nr_pages = end_pfn - start_pfn; + pfn = start_pfn; + expire = jiffies + timeout; + drain = 0; + retry_max = 5; +repeat: + /* start memory hot removal */ + ret = -EAGAIN; + if (time_after(jiffies, expire)) + goto failed_removal; + ret = -EINTR; + if (signal_pending(current)) + goto failed_removal; + ret = 0; + if (drain) { + lru_add_drain_all(); + flush_scheduled_work(); + cond_resched(); + drain_all_local_pages(); + } + + pfn = scan_lru_pages(start_pfn, end_pfn); + if (pfn) { /* We have page on LRU */ + ret = do_migrate_range(pfn, end_pfn); + if (!ret) { + drain = 1; + goto repeat; + } else { + if (ret < 0) + if (--retry_max == 0) + goto failed_removal; + yield(); + drain = 1; + goto repeat; + } + } + /* drain all zone's lru pagevec, this is asyncronous... */ + lru_add_drain_all(); + flush_scheduled_work(); + yield(); + /* drain pcp pages , this is synchrouns. */ + drain_all_local_pages(); + /* check again */ + offlined_pages = check_pages_isolated(start_pfn, end_pfn); + if (offlined_pages < 0) { + ret = -EBUSY; + goto failed_removal; + } + printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); + /* Ok, all of our target is islaoted. + We cannot do rollback at this point. */ + offline_isolated_pages(start_pfn, end_pfn); + /* reset pagetype flags */ + start_isolate_page_range(start_pfn, end_pfn); + /* removal success */ + zone = page_zone(pfn_to_page(start_pfn)); + zone->present_pages -= offlined_pages; + zone->zone_pgdat->node_present_pages -= offlined_pages; + totalram_pages -= offlined_pages; + num_physpages -= offlined_pages; + vm_total_pages = nr_free_pagecache_pages(); + writeback_set_ratelimit(); + return 0; + +failed_removal: + printk(KERN_INFO "memory offlining %lx to %lx failed\n", + start_pfn, end_pfn); + /* pushback to free area */ + undo_isolate_page_range(start_pfn, end_pfn); + return ret; +} +#else +int remove_memory(u64 start, u64 size) +{ + return -EINVAL; +} +EXPORT_SYMBOL_GPL(remove_memory); +#endif /* CONFIG_MEMORY_HOTREMOVE */ |