diff options
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 438 |
1 files changed, 400 insertions, 38 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 77ed2d773705..32efd8028bc9 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -35,9 +35,13 @@ #include <linux/hugetlb.h> #include <linux/hugetlb_cgroup.h> #include <linux/gfp.h> +#include <linux/balloon_compaction.h> #include <asm/tlbflush.h> +#define CREATE_TRACE_POINTS +#include <trace/events/migrate.h> + #include "internal.h" /* @@ -79,7 +83,30 @@ void putback_lru_pages(struct list_head *l) list_del(&page->lru); dec_zone_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); - putback_lru_page(page); + putback_lru_page(page); + } +} + +/* + * Put previously isolated pages back onto the appropriate lists + * from where they were once taken off for compaction/migration. + * + * This function shall be used instead of putback_lru_pages(), + * whenever the isolated pageset has been built by isolate_migratepages_range() + */ +void putback_movable_pages(struct list_head *l) +{ + struct page *page; + struct page *page2; + + list_for_each_entry_safe(page, page2, l, lru) { + list_del(&page->lru); + dec_zone_page_state(page, NR_ISOLATED_ANON + + page_is_file_cache(page)); + if (unlikely(balloon_page_movable(page))) + balloon_page_putback(page); + else + putback_lru_page(page); } } @@ -91,8 +118,6 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, { struct mm_struct *mm = vma->vm_mm; swp_entry_t entry; - pgd_t *pgd; - pud_t *pud; pmd_t *pmd; pte_t *ptep, pte; spinlock_t *ptl; @@ -103,19 +128,11 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, goto out; ptl = &mm->page_table_lock; } else { - pgd = pgd_offset(mm, addr); - if (!pgd_present(*pgd)) - goto out; - - pud = pud_offset(pgd, addr); - if (!pud_present(*pud)) + pmd = mm_find_pmd(mm, addr); + if (!pmd) goto out; - - pmd = pmd_offset(pud, addr); if (pmd_trans_huge(*pmd)) goto out; - if (!pmd_present(*pmd)) - goto out; ptep = pte_offset_map(pmd, addr); @@ -279,14 +296,14 @@ static int migrate_page_move_mapping(struct address_space *mapping, struct page *newpage, struct page *page, struct buffer_head *head, enum migrate_mode mode) { - int expected_count; + int expected_count = 0; void **pslot; if (!mapping) { /* Anonymous page without mapping */ if (page_count(page) != 1) return -EAGAIN; - return 0; + return MIGRATEPAGE_SUCCESS; } spin_lock_irq(&mapping->tree_lock); @@ -356,7 +373,7 @@ static int migrate_page_move_mapping(struct address_space *mapping, } spin_unlock_irq(&mapping->tree_lock); - return 0; + return MIGRATEPAGE_SUCCESS; } /* @@ -372,7 +389,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, if (!mapping) { if (page_count(page) != 1) return -EAGAIN; - return 0; + return MIGRATEPAGE_SUCCESS; } spin_lock_irq(&mapping->tree_lock); @@ -399,7 +416,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, page_unfreeze_refs(page, expected_count - 1); spin_unlock_irq(&mapping->tree_lock); - return 0; + return MIGRATEPAGE_SUCCESS; } /* @@ -407,7 +424,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, */ void migrate_page_copy(struct page *newpage, struct page *page) { - if (PageHuge(page)) + if (PageHuge(page) || PageTransHuge(page)) copy_huge_page(newpage, page); else copy_highpage(newpage, page); @@ -486,11 +503,11 @@ int migrate_page(struct address_space *mapping, rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode); - if (rc) + if (rc != MIGRATEPAGE_SUCCESS) return rc; migrate_page_copy(newpage, page); - return 0; + return MIGRATEPAGE_SUCCESS; } EXPORT_SYMBOL(migrate_page); @@ -513,7 +530,7 @@ int buffer_migrate_page(struct address_space *mapping, rc = migrate_page_move_mapping(mapping, newpage, page, head, mode); - if (rc) + if (rc != MIGRATEPAGE_SUCCESS) return rc; /* @@ -549,7 +566,7 @@ int buffer_migrate_page(struct address_space *mapping, } while (bh != head); - return 0; + return MIGRATEPAGE_SUCCESS; } EXPORT_SYMBOL(buffer_migrate_page); #endif @@ -628,7 +645,7 @@ static int fallback_migrate_page(struct address_space *mapping, * * Return value: * < 0 - error code - * == 0 - success + * MIGRATEPAGE_SUCCESS - success */ static int move_to_new_page(struct page *newpage, struct page *page, int remap_swapcache, enum migrate_mode mode) @@ -665,7 +682,7 @@ static int move_to_new_page(struct page *newpage, struct page *page, else rc = fallback_migrate_page(mapping, newpage, page, mode); - if (rc) { + if (rc != MIGRATEPAGE_SUCCESS) { newpage->mapping = NULL; } else { if (remap_swapcache) @@ -751,7 +768,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, */ if (PageAnon(page)) { /* - * Only page_lock_anon_vma() understands the subtleties of + * Only page_lock_anon_vma_read() understands the subtleties of * getting a hold on an anon_vma from outside one of its mms. */ anon_vma = page_get_anon_vma(page); @@ -778,6 +795,18 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } } + if (unlikely(balloon_page_movable(page))) { + /* + * A ballooned page does not need any special attention from + * physical to virtual reverse mapping procedures. + * Skip any attempt to unmap PTEs or to remap swap cache, + * in order to avoid burning cycles at rmap level, and perform + * the page migration right away (proteced by page lock). + */ + rc = balloon_page_migrate(newpage, page, mode); + goto uncharge; + } + /* * Corner case handling: * 1. When a new swap-cache page is read into, it is added to the LRU @@ -814,7 +843,9 @@ skip_unmap: put_anon_vma(anon_vma); uncharge: - mem_cgroup_end_migration(mem, page, newpage, rc == 0); + mem_cgroup_end_migration(mem, page, newpage, + (rc == MIGRATEPAGE_SUCCESS || + rc == MIGRATEPAGE_BALLOON_SUCCESS)); unlock: unlock_page(page); out: @@ -846,6 +877,18 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, goto out; rc = __unmap_and_move(page, newpage, force, offlining, mode); + + if (unlikely(rc == MIGRATEPAGE_BALLOON_SUCCESS)) { + /* + * A ballooned page has been migrated already. + * Now, it's the time to wrap-up counters, + * handle the page back to Buddy and return. + */ + dec_zone_page_state(page, NR_ISOLATED_ANON + + page_is_file_cache(page)); + balloon_page_free(page); + return MIGRATEPAGE_SUCCESS; + } out: if (rc != -EAGAIN) { /* @@ -958,10 +1001,11 @@ out: */ int migrate_pages(struct list_head *from, new_page_t get_new_page, unsigned long private, bool offlining, - enum migrate_mode mode) + enum migrate_mode mode, int reason) { int retry = 1; int nr_failed = 0; + int nr_succeeded = 0; int pass = 0; struct page *page; struct page *page2; @@ -987,7 +1031,8 @@ int migrate_pages(struct list_head *from, case -EAGAIN: retry++; break; - case 0: + case MIGRATEPAGE_SUCCESS: + nr_succeeded++; break; default: /* Permanent failure */ @@ -996,15 +1041,18 @@ int migrate_pages(struct list_head *from, } } } - rc = 0; + rc = nr_failed + retry; out: + if (nr_succeeded) + count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded); + if (nr_failed) + count_vm_events(PGMIGRATE_FAIL, nr_failed); + trace_mm_migrate_pages(nr_succeeded, nr_failed, mode, reason); + if (!swapwrite) current->flags &= ~PF_SWAPWRITE; - if (rc) - return rc; - - return nr_failed + retry; + return rc; } int migrate_huge_page(struct page *hpage, new_page_t get_new_page, @@ -1024,7 +1072,7 @@ int migrate_huge_page(struct page *hpage, new_page_t get_new_page, /* try again */ cond_resched(); break; - case 0: + case MIGRATEPAGE_SUCCESS: goto out; default: rc = -EIO; @@ -1139,7 +1187,8 @@ set_status: err = 0; if (!list_empty(&pagelist)) { err = migrate_pages(&pagelist, new_page_node, - (unsigned long)pm, 0, MIGRATE_SYNC); + (unsigned long)pm, 0, MIGRATE_SYNC, + MR_SYSCALL); if (err) putback_lru_pages(&pagelist); } @@ -1201,7 +1250,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, if (node < 0 || node >= MAX_NUMNODES) goto out_pm; - if (!node_state(node, N_HIGH_MEMORY)) + if (!node_state(node, N_MEMORY)) goto out_pm; err = -EACCES; @@ -1403,4 +1452,317 @@ int migrate_vmas(struct mm_struct *mm, const nodemask_t *to, } return err; } -#endif + +#ifdef CONFIG_NUMA_BALANCING +/* + * Returns true if this is a safe migration target node for misplaced NUMA + * pages. Currently it only checks the watermarks which crude + */ +static bool migrate_balanced_pgdat(struct pglist_data *pgdat, + int nr_migrate_pages) +{ + int z; + for (z = pgdat->nr_zones - 1; z >= 0; z--) { + struct zone *zone = pgdat->node_zones + z; + + if (!populated_zone(zone)) + continue; + + if (zone->all_unreclaimable) + continue; + + /* Avoid waking kswapd by allocating pages_to_migrate pages. */ + if (!zone_watermark_ok(zone, 0, + high_wmark_pages(zone) + + nr_migrate_pages, + 0, 0)) + continue; + return true; + } + return false; +} + +static struct page *alloc_misplaced_dst_page(struct page *page, + unsigned long data, + int **result) +{ + int nid = (int) data; + struct page *newpage; + + newpage = alloc_pages_exact_node(nid, + (GFP_HIGHUSER_MOVABLE | GFP_THISNODE | + __GFP_NOMEMALLOC | __GFP_NORETRY | + __GFP_NOWARN) & + ~GFP_IOFS, 0); + if (newpage) + page_xchg_last_nid(newpage, page_last_nid(page)); + + return newpage; +} + +/* + * page migration rate limiting control. + * Do not migrate more than @pages_to_migrate in a @migrate_interval_millisecs + * window of time. Default here says do not migrate more than 1280M per second. + * If a node is rate-limited then PTE NUMA updates are also rate-limited. However + * as it is faults that reset the window, pte updates will happen unconditionally + * if there has not been a fault since @pteupdate_interval_millisecs after the + * throttle window closed. + */ +static unsigned int migrate_interval_millisecs __read_mostly = 100; +static unsigned int pteupdate_interval_millisecs __read_mostly = 1000; +static unsigned int ratelimit_pages __read_mostly = 128 << (20 - PAGE_SHIFT); + +/* Returns true if NUMA migration is currently rate limited */ +bool migrate_ratelimited(int node) +{ + pg_data_t *pgdat = NODE_DATA(node); + + if (time_after(jiffies, pgdat->numabalancing_migrate_next_window + + msecs_to_jiffies(pteupdate_interval_millisecs))) + return false; + + if (pgdat->numabalancing_migrate_nr_pages < ratelimit_pages) + return false; + + return true; +} + +/* Returns true if the node is migrate rate-limited after the update */ +bool numamigrate_update_ratelimit(pg_data_t *pgdat, unsigned long nr_pages) +{ + bool rate_limited = false; + + /* + * Rate-limit the amount of data that is being migrated to a node. + * Optimal placement is no good if the memory bus is saturated and + * all the time is being spent migrating! + */ + spin_lock(&pgdat->numabalancing_migrate_lock); + if (time_after(jiffies, pgdat->numabalancing_migrate_next_window)) { + pgdat->numabalancing_migrate_nr_pages = 0; + pgdat->numabalancing_migrate_next_window = jiffies + + msecs_to_jiffies(migrate_interval_millisecs); + } + if (pgdat->numabalancing_migrate_nr_pages > ratelimit_pages) + rate_limited = true; + else + pgdat->numabalancing_migrate_nr_pages += nr_pages; + spin_unlock(&pgdat->numabalancing_migrate_lock); + + return rate_limited; +} + +int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) +{ + int ret = 0; + + /* Avoid migrating to a node that is nearly full */ + if (migrate_balanced_pgdat(pgdat, 1)) { + int page_lru; + + if (isolate_lru_page(page)) { + put_page(page); + return 0; + } + + /* Page is isolated */ + ret = 1; + page_lru = page_is_file_cache(page); + if (!PageTransHuge(page)) + inc_zone_page_state(page, NR_ISOLATED_ANON + page_lru); + else + mod_zone_page_state(page_zone(page), + NR_ISOLATED_ANON + page_lru, + HPAGE_PMD_NR); + } + + /* + * Page is either isolated or there is not enough space on the target + * node. If isolated, then it has taken a reference count and the + * callers reference can be safely dropped without the page + * disappearing underneath us during migration. Otherwise the page is + * not to be migrated but the callers reference should still be + * dropped so it does not leak. + */ + put_page(page); + + return ret; +} + +/* + * Attempt to migrate a misplaced page to the specified destination + * node. Caller is expected to have an elevated reference count on + * the page that will be dropped by this function before returning. + */ +int migrate_misplaced_page(struct page *page, int node) +{ + pg_data_t *pgdat = NODE_DATA(node); + int isolated = 0; + int nr_remaining; + LIST_HEAD(migratepages); + + /* + * Don't migrate pages that are mapped in multiple processes. + * TODO: Handle false sharing detection instead of this hammer + */ + if (page_mapcount(page) != 1) { + put_page(page); + goto out; + } + + /* + * Rate-limit the amount of data that is being migrated to a node. + * Optimal placement is no good if the memory bus is saturated and + * all the time is being spent migrating! + */ + if (numamigrate_update_ratelimit(pgdat, 1)) { + put_page(page); + goto out; + } + + isolated = numamigrate_isolate_page(pgdat, page); + if (!isolated) + goto out; + + list_add(&page->lru, &migratepages); + nr_remaining = migrate_pages(&migratepages, + alloc_misplaced_dst_page, + node, false, MIGRATE_ASYNC, + MR_NUMA_MISPLACED); + if (nr_remaining) { + putback_lru_pages(&migratepages); + isolated = 0; + } else + count_vm_numa_event(NUMA_PAGE_MIGRATE); + BUG_ON(!list_empty(&migratepages)); +out: + return isolated; +} +#endif /* CONFIG_NUMA_BALANCING */ + +#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE) +int migrate_misplaced_transhuge_page(struct mm_struct *mm, + struct vm_area_struct *vma, + pmd_t *pmd, pmd_t entry, + unsigned long address, + struct page *page, int node) +{ + unsigned long haddr = address & HPAGE_PMD_MASK; + pg_data_t *pgdat = NODE_DATA(node); + int isolated = 0; + struct page *new_page = NULL; + struct mem_cgroup *memcg = NULL; + int page_lru = page_is_file_cache(page); + + /* + * Don't migrate pages that are mapped in multiple processes. + * TODO: Handle false sharing detection instead of this hammer + */ + if (page_mapcount(page) != 1) + goto out_dropref; + + /* + * Rate-limit the amount of data that is being migrated to a node. + * Optimal placement is no good if the memory bus is saturated and + * all the time is being spent migrating! + */ + if (numamigrate_update_ratelimit(pgdat, HPAGE_PMD_NR)) + goto out_dropref; + + new_page = alloc_pages_node(node, + (GFP_TRANSHUGE | GFP_THISNODE) & ~__GFP_WAIT, HPAGE_PMD_ORDER); + if (!new_page) { + count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR); + goto out_dropref; + } + page_xchg_last_nid(new_page, page_last_nid(page)); + + isolated = numamigrate_isolate_page(pgdat, page); + if (!isolated) { + count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR); + put_page(new_page); + goto out_keep_locked; + } + + /* Prepare a page as a migration target */ + __set_page_locked(new_page); + SetPageSwapBacked(new_page); + + /* anon mapping, we can simply copy page->mapping to the new page: */ + new_page->mapping = page->mapping; + new_page->index = page->index; + migrate_page_copy(new_page, page); + WARN_ON(PageLRU(new_page)); + + /* Recheck the target PMD */ + spin_lock(&mm->page_table_lock); + if (unlikely(!pmd_same(*pmd, entry))) { + spin_unlock(&mm->page_table_lock); + + /* Reverse changes made by migrate_page_copy() */ + if (TestClearPageActive(new_page)) + SetPageActive(page); + if (TestClearPageUnevictable(new_page)) + SetPageUnevictable(page); + mlock_migrate_page(page, new_page); + + unlock_page(new_page); + put_page(new_page); /* Free it */ + + unlock_page(page); + putback_lru_page(page); + + count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR); + goto out; + } + + /* + * Traditional migration needs to prepare the memcg charge + * transaction early to prevent the old page from being + * uncharged when installing migration entries. Here we can + * save the potential rollback and start the charge transfer + * only when migration is already known to end successfully. + */ + mem_cgroup_prepare_migration(page, new_page, &memcg); + + entry = mk_pmd(new_page, vma->vm_page_prot); + entry = pmd_mknonnuma(entry); + entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); + entry = pmd_mkhuge(entry); + + page_add_new_anon_rmap(new_page, vma, haddr); + + set_pmd_at(mm, haddr, pmd, entry); + update_mmu_cache_pmd(vma, address, entry); + page_remove_rmap(page); + /* + * Finish the charge transaction under the page table lock to + * prevent split_huge_page() from dividing up the charge + * before it's fully transferred to the new page. + */ + mem_cgroup_end_migration(memcg, page, new_page, true); + spin_unlock(&mm->page_table_lock); + + unlock_page(new_page); + unlock_page(page); + put_page(page); /* Drop the rmap reference */ + put_page(page); /* Drop the LRU isolation reference */ + + count_vm_events(PGMIGRATE_SUCCESS, HPAGE_PMD_NR); + count_vm_numa_events(NUMA_PAGE_MIGRATE, HPAGE_PMD_NR); + +out: + mod_zone_page_state(page_zone(page), + NR_ISOLATED_ANON + page_lru, + -HPAGE_PMD_NR); + return isolated; + +out_dropref: + put_page(page); +out_keep_locked: + return 0; +} +#endif /* CONFIG_NUMA_BALANCING */ + +#endif /* CONFIG_NUMA */ |