diff options
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 494 |
1 files changed, 421 insertions, 73 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 77ed2d773705..3bbaf5d230b0 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); @@ -143,8 +160,10 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, if (is_write_migration_entry(entry)) pte = pte_mkwrite(pte); #ifdef CONFIG_HUGETLB_PAGE - if (PageHuge(new)) + if (PageHuge(new)) { pte = pte_mkhuge(pte); + pte = arch_make_huge_pte(pte, vma, new, 0); + } #endif flush_cache_page(vma, addr, pte_pfn(pte)); set_pte_at(mm, addr, ptep, pte); @@ -279,14 +298,14 @@ 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 +375,7 @@ static int migrate_page_move_mapping(struct address_space *mapping, } spin_unlock_irq(&mapping->tree_lock); - return 0; + return MIGRATEPAGE_SUCCESS; } /* @@ -372,7 +391,7 @@ 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 +418,7 @@ 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 +426,7 @@ 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); @@ -445,7 +464,10 @@ void migrate_page_copy(struct page *newpage, struct page *page) mlock_migrate_page(newpage, page); ksm_migrate_page(newpage, page); - + /* + * Please do not reorder this without considering how mm/ksm.c's + * get_ksm_page() depends upon ksm_migrate_page() and PageSwapCache(). + */ ClearPageSwapCache(page); ClearPagePrivate(page); set_page_private(page, 0); @@ -486,11 +508,11 @@ 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 +535,7 @@ 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 +571,7 @@ int buffer_migrate_page(struct address_space *mapping, } while (bh != head); - return 0; + return MIGRATEPAGE_SUCCESS; } EXPORT_SYMBOL(buffer_migrate_page); #endif @@ -628,7 +650,7 @@ 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 +687,7 @@ 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) @@ -679,7 +701,7 @@ static int move_to_new_page(struct page *newpage, struct page *page, } static int __unmap_and_move(struct page *page, struct page *newpage, - int force, bool offlining, enum migrate_mode mode) + int force, enum migrate_mode mode) { int rc = -EAGAIN; int remap_swapcache = 1; @@ -709,20 +731,6 @@ static int __unmap_and_move(struct page *page, struct page *newpage, lock_page(page); } - /* - * Only memory hotplug's offline_pages() caller has locked out KSM, - * and can safely migrate a KSM page. The other cases have skipped - * PageKsm along with PageReserved - but it is only now when we have - * the page lock that we can be certain it will not go KSM beneath us - * (KSM will not upgrade a page from PageAnon to PageKsm when it sees - * its pagecount raised, but only here do we take the page lock which - * serializes that). - */ - if (PageKsm(page) && !offlining) { - rc = -EBUSY; - goto unlock; - } - /* charge against new page */ mem_cgroup_prepare_migration(page, newpage, &mem); @@ -749,9 +757,9 @@ static int __unmap_and_move(struct page *page, struct page *newpage, * File Caches may use write_page() or lock_page() in migration, then, * just care Anon page here. */ - if (PageAnon(page)) { + if (PageAnon(page) && !PageKsm(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 +786,18 @@ 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 @@ -814,8 +834,9 @@ skip_unmap: put_anon_vma(anon_vma); uncharge: - mem_cgroup_end_migration(mem, page, newpage, rc == 0); -unlock: + mem_cgroup_end_migration(mem, page, newpage, + (rc == MIGRATEPAGE_SUCCESS || + rc == MIGRATEPAGE_BALLOON_SUCCESS)); unlock_page(page); out: return rc; @@ -826,8 +847,7 @@ out: * to the newly allocated page in newpage. */ static int unmap_and_move(new_page_t get_new_page, unsigned long private, - struct page *page, int force, bool offlining, - enum migrate_mode mode) + struct page *page, int force, enum migrate_mode mode) { int rc = 0; int *result = NULL; @@ -845,7 +865,19 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, if (unlikely(split_huge_page(page))) goto out; - rc = __unmap_and_move(page, newpage, force, offlining, mode); + rc = __unmap_and_move(page, newpage, force, 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) { /* @@ -893,8 +925,7 @@ out: */ static int unmap_and_move_huge_page(new_page_t get_new_page, unsigned long private, struct page *hpage, - int force, bool offlining, - enum migrate_mode mode) + int force, enum migrate_mode mode) { int rc = 0; int *result = NULL; @@ -956,12 +987,12 @@ out: * * Return: Number of pages not migrated or error code. */ -int migrate_pages(struct list_head *from, - new_page_t get_new_page, unsigned long private, bool offlining, - enum migrate_mode mode) +int migrate_pages(struct list_head *from, new_page_t get_new_page, + unsigned long private, 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; @@ -978,8 +1009,7 @@ int migrate_pages(struct list_head *from, cond_resched(); rc = unmap_and_move(get_new_page, private, - page, pass > 2, offlining, - mode); + page, pass > 2, mode); switch(rc) { case -ENOMEM: @@ -987,7 +1017,8 @@ int migrate_pages(struct list_head *from, case -EAGAIN: retry++; break; - case 0: + case MIGRATEPAGE_SUCCESS: + nr_succeeded++; break; default: /* Permanent failure */ @@ -996,27 +1027,28 @@ 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, - unsigned long private, bool offlining, - enum migrate_mode mode) + unsigned long private, enum migrate_mode mode) { int pass, rc; for (pass = 0; pass < 10; pass++) { - rc = unmap_and_move_huge_page(get_new_page, - private, hpage, pass > 2, offlining, - mode); + rc = unmap_and_move_huge_page(get_new_page, private, + hpage, pass > 2, mode); switch (rc) { case -ENOMEM: goto out; @@ -1024,7 +1056,7 @@ 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; @@ -1102,7 +1134,7 @@ static int do_move_page_to_node_array(struct mm_struct *mm, goto set_status; /* Use PageReserved to check for zero page */ - if (PageReserved(page) || PageKsm(page)) + if (PageReserved(page)) goto put_and_set; pp->page = page; @@ -1139,7 +1171,7 @@ set_status: err = 0; if (!list_empty(&pagelist)) { err = migrate_pages(&pagelist, new_page_node, - (unsigned long)pm, 0, MIGRATE_SYNC); + (unsigned long)pm, MIGRATE_SYNC, MR_SYSCALL); if (err) putback_lru_pages(&pagelist); } @@ -1201,7 +1233,7 @@ 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; @@ -1263,7 +1295,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, err = -ENOENT; /* Use PageReserved to check for zero page */ - if (!page || PageReserved(page) || PageKsm(page)) + if (!page || PageReserved(page)) goto set_status; err = page_to_nid(page); @@ -1403,4 +1435,320 @@ 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, + unsigned long 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_nid_xchg_last(newpage, page_nid_last(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 page_lru; + + VM_BUG_ON(compound_order(page) && !PageTransHuge(page)); + + /* Avoid migrating to a node that is nearly full */ + if (!migrate_balanced_pgdat(pgdat, 1UL << compound_order(page))) + return 0; + + if (isolate_lru_page(page)) + return 0; + + /* + * migrate_misplaced_transhuge_page() skips page migration's usual + * check on page_count(), so we must do it here, now that the page + * has been isolated: a GUP pin, or any other pin, prevents migration. + * The expected page count is 3: 1 for page's mapcount and 1 for the + * caller's pin and 1 for the reference taken by isolate_lru_page(). + */ + if (PageTransHuge(page) && page_count(page) != 3) { + putback_lru_page(page); + return 0; + } + + page_lru = page_is_file_cache(page); + mod_zone_page_state(page_zone(page), NR_ISOLATED_ANON + page_lru, + hpage_nr_pages(page)); + + /* + * Isolating the page has taken another reference, so the + * caller's reference can be safely dropped without the page + * disappearing underneath us during migration. + */ + put_page(page); + return 1; +} + +/* + * 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; + 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) + 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)) + 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, 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)); + return isolated; + +out: + put_page(page); + return 0; +} +#endif /* CONFIG_NUMA_BALANCING */ + +#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE) +/* + * Migrates a THP to a given target node. page must be locked and is unlocked + * before returning. + */ +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) + goto out_fail; + + page_nid_xchg_last(new_page, page_nid_last(page)); + + isolated = numamigrate_isolate_page(pgdat, page); + if (!isolated) { + put_page(new_page); + goto out_fail; + } + + /* 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); + isolated = 0; + 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_fail: + count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR); +out_dropref: + unlock_page(page); + put_page(page); + return 0; +} +#endif /* CONFIG_NUMA_BALANCING */ + +#endif /* CONFIG_NUMA */ |