171e3aac0SAndrea Arcangeli /* 271e3aac0SAndrea Arcangeli * Copyright (C) 2009 Red Hat, Inc. 371e3aac0SAndrea Arcangeli * 471e3aac0SAndrea Arcangeli * This work is licensed under the terms of the GNU GPL, version 2. See 571e3aac0SAndrea Arcangeli * the COPYING file in the top-level directory. 671e3aac0SAndrea Arcangeli */ 771e3aac0SAndrea Arcangeli 8ae3a8c1cSAndrew Morton #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9ae3a8c1cSAndrew Morton 1071e3aac0SAndrea Arcangeli #include <linux/mm.h> 1171e3aac0SAndrea Arcangeli #include <linux/sched.h> 1271e3aac0SAndrea Arcangeli #include <linux/highmem.h> 1371e3aac0SAndrea Arcangeli #include <linux/hugetlb.h> 1471e3aac0SAndrea Arcangeli #include <linux/mmu_notifier.h> 1571e3aac0SAndrea Arcangeli #include <linux/rmap.h> 1671e3aac0SAndrea Arcangeli #include <linux/swap.h> 1797ae1749SKirill A. Shutemov #include <linux/shrinker.h> 18ba76149fSAndrea Arcangeli #include <linux/mm_inline.h> 19ba76149fSAndrea Arcangeli #include <linux/kthread.h> 20ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 21878aee7dSAndrea Arcangeli #include <linux/freezer.h> 22a664b2d8SAndrea Arcangeli #include <linux/mman.h> 23325adeb5SRalf Baechle #include <linux/pagemap.h> 244daae3b4SMel Gorman #include <linux/migrate.h> 2543b5fbbdSSasha Levin #include <linux/hashtable.h> 2697ae1749SKirill A. Shutemov 2771e3aac0SAndrea Arcangeli #include <asm/tlb.h> 2871e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 2971e3aac0SAndrea Arcangeli #include "internal.h" 3071e3aac0SAndrea Arcangeli 31ba76149fSAndrea Arcangeli /* 328bfa3f9aSJianguo Wu * By default transparent hugepage support is disabled in order that avoid 338bfa3f9aSJianguo Wu * to risk increase the memory footprint of applications without a guaranteed 348bfa3f9aSJianguo Wu * benefit. When transparent hugepage support is enabled, is for all mappings, 358bfa3f9aSJianguo Wu * and khugepaged scans all mappings. 368bfa3f9aSJianguo Wu * Defrag is invoked by khugepaged hugepage allocations and by page faults 378bfa3f9aSJianguo Wu * for all hugepage allocations. 38ba76149fSAndrea Arcangeli */ 3971e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 4013ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 41ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 4213ece886SAndrea Arcangeli #endif 4313ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 4413ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 4513ece886SAndrea Arcangeli #endif 46d39d33c3SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| 4779da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 4879da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 49ba76149fSAndrea Arcangeli 50ba76149fSAndrea Arcangeli /* default scan 8*512 pte (or vmas) every 30 second */ 51ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; 52ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_collapsed; 53ba76149fSAndrea Arcangeli static unsigned int khugepaged_full_scans; 54ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; 55ba76149fSAndrea Arcangeli /* during fragmentation poll the hugepage allocator once every minute */ 56ba76149fSAndrea Arcangeli static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; 57ba76149fSAndrea Arcangeli static struct task_struct *khugepaged_thread __read_mostly; 58ba76149fSAndrea Arcangeli static DEFINE_MUTEX(khugepaged_mutex); 59ba76149fSAndrea Arcangeli static DEFINE_SPINLOCK(khugepaged_mm_lock); 60ba76149fSAndrea Arcangeli static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); 61ba76149fSAndrea Arcangeli /* 62ba76149fSAndrea Arcangeli * default collapse hugepages if there is at least one pte mapped like 63ba76149fSAndrea Arcangeli * it would have happened if the vma was large enough during page 64ba76149fSAndrea Arcangeli * fault. 65ba76149fSAndrea Arcangeli */ 66ba76149fSAndrea Arcangeli static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; 67ba76149fSAndrea Arcangeli 68ba76149fSAndrea Arcangeli static int khugepaged(void *none); 69ba76149fSAndrea Arcangeli static int khugepaged_slab_init(void); 70ba76149fSAndrea Arcangeli 7143b5fbbdSSasha Levin #define MM_SLOTS_HASH_BITS 10 7243b5fbbdSSasha Levin static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); 7343b5fbbdSSasha Levin 74ba76149fSAndrea Arcangeli static struct kmem_cache *mm_slot_cache __read_mostly; 75ba76149fSAndrea Arcangeli 76ba76149fSAndrea Arcangeli /** 77ba76149fSAndrea Arcangeli * struct mm_slot - hash lookup from mm to mm_slot 78ba76149fSAndrea Arcangeli * @hash: hash collision list 79ba76149fSAndrea Arcangeli * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head 80ba76149fSAndrea Arcangeli * @mm: the mm that this information is valid for 81ba76149fSAndrea Arcangeli */ 82ba76149fSAndrea Arcangeli struct mm_slot { 83ba76149fSAndrea Arcangeli struct hlist_node hash; 84ba76149fSAndrea Arcangeli struct list_head mm_node; 85ba76149fSAndrea Arcangeli struct mm_struct *mm; 86ba76149fSAndrea Arcangeli }; 87ba76149fSAndrea Arcangeli 88ba76149fSAndrea Arcangeli /** 89ba76149fSAndrea Arcangeli * struct khugepaged_scan - cursor for scanning 90ba76149fSAndrea Arcangeli * @mm_head: the head of the mm list to scan 91ba76149fSAndrea Arcangeli * @mm_slot: the current mm_slot we are scanning 92ba76149fSAndrea Arcangeli * @address: the next address inside that to be scanned 93ba76149fSAndrea Arcangeli * 94ba76149fSAndrea Arcangeli * There is only the one khugepaged_scan instance of this cursor structure. 95ba76149fSAndrea Arcangeli */ 96ba76149fSAndrea Arcangeli struct khugepaged_scan { 97ba76149fSAndrea Arcangeli struct list_head mm_head; 98ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 99ba76149fSAndrea Arcangeli unsigned long address; 1002f1da642SH Hartley Sweeten }; 1012f1da642SH Hartley Sweeten static struct khugepaged_scan khugepaged_scan = { 102ba76149fSAndrea Arcangeli .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), 103ba76149fSAndrea Arcangeli }; 104ba76149fSAndrea Arcangeli 105f000565aSAndrea Arcangeli 106f000565aSAndrea Arcangeli static int set_recommended_min_free_kbytes(void) 107f000565aSAndrea Arcangeli { 108f000565aSAndrea Arcangeli struct zone *zone; 109f000565aSAndrea Arcangeli int nr_zones = 0; 110f000565aSAndrea Arcangeli unsigned long recommended_min; 111f000565aSAndrea Arcangeli 11217c230afSXiao Guangrong if (!khugepaged_enabled()) 113f000565aSAndrea Arcangeli return 0; 114f000565aSAndrea Arcangeli 115f000565aSAndrea Arcangeli for_each_populated_zone(zone) 116f000565aSAndrea Arcangeli nr_zones++; 117f000565aSAndrea Arcangeli 118f000565aSAndrea Arcangeli /* Make sure at least 2 hugepages are free for MIGRATE_RESERVE */ 119f000565aSAndrea Arcangeli recommended_min = pageblock_nr_pages * nr_zones * 2; 120f000565aSAndrea Arcangeli 121f000565aSAndrea Arcangeli /* 122f000565aSAndrea Arcangeli * Make sure that on average at least two pageblocks are almost free 123f000565aSAndrea Arcangeli * of another type, one for a migratetype to fall back to and a 124f000565aSAndrea Arcangeli * second to avoid subsequent fallbacks of other types There are 3 125f000565aSAndrea Arcangeli * MIGRATE_TYPES we care about. 126f000565aSAndrea Arcangeli */ 127f000565aSAndrea Arcangeli recommended_min += pageblock_nr_pages * nr_zones * 128f000565aSAndrea Arcangeli MIGRATE_PCPTYPES * MIGRATE_PCPTYPES; 129f000565aSAndrea Arcangeli 130f000565aSAndrea Arcangeli /* don't ever allow to reserve more than 5% of the lowmem */ 131f000565aSAndrea Arcangeli recommended_min = min(recommended_min, 132f000565aSAndrea Arcangeli (unsigned long) nr_free_buffer_pages() / 20); 133f000565aSAndrea Arcangeli recommended_min <<= (PAGE_SHIFT-10); 134f000565aSAndrea Arcangeli 13542aa83cbSHan Pingtian if (recommended_min > min_free_kbytes) { 13642aa83cbSHan Pingtian if (user_min_free_kbytes >= 0) 13742aa83cbSHan Pingtian pr_info("raising min_free_kbytes from %d to %lu " 13842aa83cbSHan Pingtian "to help transparent hugepage allocations\n", 13942aa83cbSHan Pingtian min_free_kbytes, recommended_min); 14042aa83cbSHan Pingtian 141f000565aSAndrea Arcangeli min_free_kbytes = recommended_min; 14242aa83cbSHan Pingtian } 143f000565aSAndrea Arcangeli setup_per_zone_wmarks(); 144f000565aSAndrea Arcangeli return 0; 145f000565aSAndrea Arcangeli } 146f000565aSAndrea Arcangeli late_initcall(set_recommended_min_free_kbytes); 147f000565aSAndrea Arcangeli 148ba76149fSAndrea Arcangeli static int start_khugepaged(void) 149ba76149fSAndrea Arcangeli { 150ba76149fSAndrea Arcangeli int err = 0; 151ba76149fSAndrea Arcangeli if (khugepaged_enabled()) { 152ba76149fSAndrea Arcangeli if (!khugepaged_thread) 153ba76149fSAndrea Arcangeli khugepaged_thread = kthread_run(khugepaged, NULL, 154ba76149fSAndrea Arcangeli "khugepaged"); 155ba76149fSAndrea Arcangeli if (unlikely(IS_ERR(khugepaged_thread))) { 156ae3a8c1cSAndrew Morton pr_err("khugepaged: kthread_run(khugepaged) failed\n"); 157ba76149fSAndrea Arcangeli err = PTR_ERR(khugepaged_thread); 158ba76149fSAndrea Arcangeli khugepaged_thread = NULL; 159ba76149fSAndrea Arcangeli } 160911891afSXiao Guangrong 161911891afSXiao Guangrong if (!list_empty(&khugepaged_scan.mm_head)) 162ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 163f000565aSAndrea Arcangeli 164f000565aSAndrea Arcangeli set_recommended_min_free_kbytes(); 165911891afSXiao Guangrong } else if (khugepaged_thread) { 166911891afSXiao Guangrong kthread_stop(khugepaged_thread); 167911891afSXiao Guangrong khugepaged_thread = NULL; 168911891afSXiao Guangrong } 169637e3a27SXiao Guangrong 170ba76149fSAndrea Arcangeli return err; 171ba76149fSAndrea Arcangeli } 17271e3aac0SAndrea Arcangeli 17397ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 1745918d10aSKirill A. Shutemov static struct page *huge_zero_page __read_mostly; 1754a6c1297SKirill A. Shutemov 1765918d10aSKirill A. Shutemov static inline bool is_huge_zero_page(struct page *page) 1774a6c1297SKirill A. Shutemov { 1785918d10aSKirill A. Shutemov return ACCESS_ONCE(huge_zero_page) == page; 1794a6c1297SKirill A. Shutemov } 1804a6c1297SKirill A. Shutemov 1814a6c1297SKirill A. Shutemov static inline bool is_huge_zero_pmd(pmd_t pmd) 1824a6c1297SKirill A. Shutemov { 1835918d10aSKirill A. Shutemov return is_huge_zero_page(pmd_page(pmd)); 1844a6c1297SKirill A. Shutemov } 1854a6c1297SKirill A. Shutemov 1865918d10aSKirill A. Shutemov static struct page *get_huge_zero_page(void) 18797ae1749SKirill A. Shutemov { 18897ae1749SKirill A. Shutemov struct page *zero_page; 18997ae1749SKirill A. Shutemov retry: 19097ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 1915918d10aSKirill A. Shutemov return ACCESS_ONCE(huge_zero_page); 19297ae1749SKirill A. Shutemov 19397ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 19497ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 195d8a8e1f0SKirill A. Shutemov if (!zero_page) { 196d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 1975918d10aSKirill A. Shutemov return NULL; 198d8a8e1f0SKirill A. Shutemov } 199d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC); 20097ae1749SKirill A. Shutemov preempt_disable(); 2015918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 20297ae1749SKirill A. Shutemov preempt_enable(); 20397ae1749SKirill A. Shutemov __free_page(zero_page); 20497ae1749SKirill A. Shutemov goto retry; 20597ae1749SKirill A. Shutemov } 20697ae1749SKirill A. Shutemov 20797ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 20897ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 20997ae1749SKirill A. Shutemov preempt_enable(); 2105918d10aSKirill A. Shutemov return ACCESS_ONCE(huge_zero_page); 21197ae1749SKirill A. Shutemov } 21297ae1749SKirill A. Shutemov 21397ae1749SKirill A. Shutemov static void put_huge_zero_page(void) 21497ae1749SKirill A. Shutemov { 21597ae1749SKirill A. Shutemov /* 21697ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 21797ae1749SKirill A. Shutemov * last reference. 21897ae1749SKirill A. Shutemov */ 21997ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 22097ae1749SKirill A. Shutemov } 22197ae1749SKirill A. Shutemov 22248896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 22397ae1749SKirill A. Shutemov struct shrink_control *sc) 22497ae1749SKirill A. Shutemov { 22597ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 22697ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 22748896466SGlauber Costa } 22897ae1749SKirill A. Shutemov 22948896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 23048896466SGlauber Costa struct shrink_control *sc) 23148896466SGlauber Costa { 23297ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2335918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2345918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2355918d10aSKirill A. Shutemov __free_page(zero_page); 23648896466SGlauber Costa return HPAGE_PMD_NR; 23797ae1749SKirill A. Shutemov } 23897ae1749SKirill A. Shutemov 23997ae1749SKirill A. Shutemov return 0; 24097ae1749SKirill A. Shutemov } 24197ae1749SKirill A. Shutemov 24297ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 24348896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 24448896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 24597ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 24697ae1749SKirill A. Shutemov }; 24797ae1749SKirill A. Shutemov 24871e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 249ba76149fSAndrea Arcangeli 25071e3aac0SAndrea Arcangeli static ssize_t double_flag_show(struct kobject *kobj, 25171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 25271e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 25371e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 25471e3aac0SAndrea Arcangeli { 25571e3aac0SAndrea Arcangeli if (test_bit(enabled, &transparent_hugepage_flags)) { 25671e3aac0SAndrea Arcangeli VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); 25771e3aac0SAndrea Arcangeli return sprintf(buf, "[always] madvise never\n"); 25871e3aac0SAndrea Arcangeli } else if (test_bit(req_madv, &transparent_hugepage_flags)) 25971e3aac0SAndrea Arcangeli return sprintf(buf, "always [madvise] never\n"); 26071e3aac0SAndrea Arcangeli else 26171e3aac0SAndrea Arcangeli return sprintf(buf, "always madvise [never]\n"); 26271e3aac0SAndrea Arcangeli } 26371e3aac0SAndrea Arcangeli static ssize_t double_flag_store(struct kobject *kobj, 26471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 26571e3aac0SAndrea Arcangeli const char *buf, size_t count, 26671e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 26771e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 26871e3aac0SAndrea Arcangeli { 26971e3aac0SAndrea Arcangeli if (!memcmp("always", buf, 27071e3aac0SAndrea Arcangeli min(sizeof("always")-1, count))) { 27171e3aac0SAndrea Arcangeli set_bit(enabled, &transparent_hugepage_flags); 27271e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 27371e3aac0SAndrea Arcangeli } else if (!memcmp("madvise", buf, 27471e3aac0SAndrea Arcangeli min(sizeof("madvise")-1, count))) { 27571e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 27671e3aac0SAndrea Arcangeli set_bit(req_madv, &transparent_hugepage_flags); 27771e3aac0SAndrea Arcangeli } else if (!memcmp("never", buf, 27871e3aac0SAndrea Arcangeli min(sizeof("never")-1, count))) { 27971e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 28071e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 28171e3aac0SAndrea Arcangeli } else 28271e3aac0SAndrea Arcangeli return -EINVAL; 28371e3aac0SAndrea Arcangeli 28471e3aac0SAndrea Arcangeli return count; 28571e3aac0SAndrea Arcangeli } 28671e3aac0SAndrea Arcangeli 28771e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 28871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 28971e3aac0SAndrea Arcangeli { 29071e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 29171e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 29271e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 29371e3aac0SAndrea Arcangeli } 29471e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 29571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 29671e3aac0SAndrea Arcangeli const char *buf, size_t count) 29771e3aac0SAndrea Arcangeli { 298ba76149fSAndrea Arcangeli ssize_t ret; 299ba76149fSAndrea Arcangeli 300ba76149fSAndrea Arcangeli ret = double_flag_store(kobj, attr, buf, count, 30171e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 30271e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 303ba76149fSAndrea Arcangeli 304ba76149fSAndrea Arcangeli if (ret > 0) { 305911891afSXiao Guangrong int err; 306911891afSXiao Guangrong 307911891afSXiao Guangrong mutex_lock(&khugepaged_mutex); 308911891afSXiao Guangrong err = start_khugepaged(); 309911891afSXiao Guangrong mutex_unlock(&khugepaged_mutex); 310911891afSXiao Guangrong 311ba76149fSAndrea Arcangeli if (err) 312ba76149fSAndrea Arcangeli ret = err; 313ba76149fSAndrea Arcangeli } 314ba76149fSAndrea Arcangeli 315ba76149fSAndrea Arcangeli return ret; 31671e3aac0SAndrea Arcangeli } 31771e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 31871e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 31971e3aac0SAndrea Arcangeli 32071e3aac0SAndrea Arcangeli static ssize_t single_flag_show(struct kobject *kobj, 32171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 32271e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 32371e3aac0SAndrea Arcangeli { 324e27e6151SBen Hutchings return sprintf(buf, "%d\n", 325e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 32671e3aac0SAndrea Arcangeli } 327e27e6151SBen Hutchings 32871e3aac0SAndrea Arcangeli static ssize_t single_flag_store(struct kobject *kobj, 32971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 33071e3aac0SAndrea Arcangeli const char *buf, size_t count, 33171e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 33271e3aac0SAndrea Arcangeli { 333e27e6151SBen Hutchings unsigned long value; 334e27e6151SBen Hutchings int ret; 335e27e6151SBen Hutchings 336e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 337e27e6151SBen Hutchings if (ret < 0) 338e27e6151SBen Hutchings return ret; 339e27e6151SBen Hutchings if (value > 1) 34071e3aac0SAndrea Arcangeli return -EINVAL; 34171e3aac0SAndrea Arcangeli 342e27e6151SBen Hutchings if (value) 343e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 344e27e6151SBen Hutchings else 345e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 346e27e6151SBen Hutchings 34771e3aac0SAndrea Arcangeli return count; 34871e3aac0SAndrea Arcangeli } 34971e3aac0SAndrea Arcangeli 35071e3aac0SAndrea Arcangeli /* 35171e3aac0SAndrea Arcangeli * Currently defrag only disables __GFP_NOWAIT for allocation. A blind 35271e3aac0SAndrea Arcangeli * __GFP_REPEAT is too aggressive, it's never worth swapping tons of 35371e3aac0SAndrea Arcangeli * memory just to allocate one more hugepage. 35471e3aac0SAndrea Arcangeli */ 35571e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 35671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 35771e3aac0SAndrea Arcangeli { 35871e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 35971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 36071e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 36171e3aac0SAndrea Arcangeli } 36271e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 36371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 36471e3aac0SAndrea Arcangeli const char *buf, size_t count) 36571e3aac0SAndrea Arcangeli { 36671e3aac0SAndrea Arcangeli return double_flag_store(kobj, attr, buf, count, 36771e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 36871e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 36971e3aac0SAndrea Arcangeli } 37071e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 37171e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 37271e3aac0SAndrea Arcangeli 37379da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 37479da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 37579da5407SKirill A. Shutemov { 37679da5407SKirill A. Shutemov return single_flag_show(kobj, attr, buf, 37779da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 37879da5407SKirill A. Shutemov } 37979da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 38079da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 38179da5407SKirill A. Shutemov { 38279da5407SKirill A. Shutemov return single_flag_store(kobj, attr, buf, count, 38379da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 38479da5407SKirill A. Shutemov } 38579da5407SKirill A. Shutemov static struct kobj_attribute use_zero_page_attr = 38679da5407SKirill A. Shutemov __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); 38771e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 38871e3aac0SAndrea Arcangeli static ssize_t debug_cow_show(struct kobject *kobj, 38971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 39071e3aac0SAndrea Arcangeli { 39171e3aac0SAndrea Arcangeli return single_flag_show(kobj, attr, buf, 39271e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 39371e3aac0SAndrea Arcangeli } 39471e3aac0SAndrea Arcangeli static ssize_t debug_cow_store(struct kobject *kobj, 39571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 39671e3aac0SAndrea Arcangeli const char *buf, size_t count) 39771e3aac0SAndrea Arcangeli { 39871e3aac0SAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 39971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 40071e3aac0SAndrea Arcangeli } 40171e3aac0SAndrea Arcangeli static struct kobj_attribute debug_cow_attr = 40271e3aac0SAndrea Arcangeli __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); 40371e3aac0SAndrea Arcangeli #endif /* CONFIG_DEBUG_VM */ 40471e3aac0SAndrea Arcangeli 40571e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 40671e3aac0SAndrea Arcangeli &enabled_attr.attr, 40771e3aac0SAndrea Arcangeli &defrag_attr.attr, 40879da5407SKirill A. Shutemov &use_zero_page_attr.attr, 40971e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 41071e3aac0SAndrea Arcangeli &debug_cow_attr.attr, 41171e3aac0SAndrea Arcangeli #endif 41271e3aac0SAndrea Arcangeli NULL, 41371e3aac0SAndrea Arcangeli }; 41471e3aac0SAndrea Arcangeli 41571e3aac0SAndrea Arcangeli static struct attribute_group hugepage_attr_group = { 41671e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 417ba76149fSAndrea Arcangeli }; 418ba76149fSAndrea Arcangeli 419ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, 420ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 421ba76149fSAndrea Arcangeli char *buf) 422ba76149fSAndrea Arcangeli { 423ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); 424ba76149fSAndrea Arcangeli } 425ba76149fSAndrea Arcangeli 426ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, 427ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 428ba76149fSAndrea Arcangeli const char *buf, size_t count) 429ba76149fSAndrea Arcangeli { 430ba76149fSAndrea Arcangeli unsigned long msecs; 431ba76149fSAndrea Arcangeli int err; 432ba76149fSAndrea Arcangeli 4333dbb95f7SJingoo Han err = kstrtoul(buf, 10, &msecs); 434ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 435ba76149fSAndrea Arcangeli return -EINVAL; 436ba76149fSAndrea Arcangeli 437ba76149fSAndrea Arcangeli khugepaged_scan_sleep_millisecs = msecs; 438ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 439ba76149fSAndrea Arcangeli 440ba76149fSAndrea Arcangeli return count; 441ba76149fSAndrea Arcangeli } 442ba76149fSAndrea Arcangeli static struct kobj_attribute scan_sleep_millisecs_attr = 443ba76149fSAndrea Arcangeli __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, 444ba76149fSAndrea Arcangeli scan_sleep_millisecs_store); 445ba76149fSAndrea Arcangeli 446ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, 447ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 448ba76149fSAndrea Arcangeli char *buf) 449ba76149fSAndrea Arcangeli { 450ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); 451ba76149fSAndrea Arcangeli } 452ba76149fSAndrea Arcangeli 453ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, 454ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 455ba76149fSAndrea Arcangeli const char *buf, size_t count) 456ba76149fSAndrea Arcangeli { 457ba76149fSAndrea Arcangeli unsigned long msecs; 458ba76149fSAndrea Arcangeli int err; 459ba76149fSAndrea Arcangeli 4603dbb95f7SJingoo Han err = kstrtoul(buf, 10, &msecs); 461ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 462ba76149fSAndrea Arcangeli return -EINVAL; 463ba76149fSAndrea Arcangeli 464ba76149fSAndrea Arcangeli khugepaged_alloc_sleep_millisecs = msecs; 465ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 466ba76149fSAndrea Arcangeli 467ba76149fSAndrea Arcangeli return count; 468ba76149fSAndrea Arcangeli } 469ba76149fSAndrea Arcangeli static struct kobj_attribute alloc_sleep_millisecs_attr = 470ba76149fSAndrea Arcangeli __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, 471ba76149fSAndrea Arcangeli alloc_sleep_millisecs_store); 472ba76149fSAndrea Arcangeli 473ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_show(struct kobject *kobj, 474ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 475ba76149fSAndrea Arcangeli char *buf) 476ba76149fSAndrea Arcangeli { 477ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_to_scan); 478ba76149fSAndrea Arcangeli } 479ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_store(struct kobject *kobj, 480ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 481ba76149fSAndrea Arcangeli const char *buf, size_t count) 482ba76149fSAndrea Arcangeli { 483ba76149fSAndrea Arcangeli int err; 484ba76149fSAndrea Arcangeli unsigned long pages; 485ba76149fSAndrea Arcangeli 4863dbb95f7SJingoo Han err = kstrtoul(buf, 10, &pages); 487ba76149fSAndrea Arcangeli if (err || !pages || pages > UINT_MAX) 488ba76149fSAndrea Arcangeli return -EINVAL; 489ba76149fSAndrea Arcangeli 490ba76149fSAndrea Arcangeli khugepaged_pages_to_scan = pages; 491ba76149fSAndrea Arcangeli 492ba76149fSAndrea Arcangeli return count; 493ba76149fSAndrea Arcangeli } 494ba76149fSAndrea Arcangeli static struct kobj_attribute pages_to_scan_attr = 495ba76149fSAndrea Arcangeli __ATTR(pages_to_scan, 0644, pages_to_scan_show, 496ba76149fSAndrea Arcangeli pages_to_scan_store); 497ba76149fSAndrea Arcangeli 498ba76149fSAndrea Arcangeli static ssize_t pages_collapsed_show(struct kobject *kobj, 499ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 500ba76149fSAndrea Arcangeli char *buf) 501ba76149fSAndrea Arcangeli { 502ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_collapsed); 503ba76149fSAndrea Arcangeli } 504ba76149fSAndrea Arcangeli static struct kobj_attribute pages_collapsed_attr = 505ba76149fSAndrea Arcangeli __ATTR_RO(pages_collapsed); 506ba76149fSAndrea Arcangeli 507ba76149fSAndrea Arcangeli static ssize_t full_scans_show(struct kobject *kobj, 508ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 509ba76149fSAndrea Arcangeli char *buf) 510ba76149fSAndrea Arcangeli { 511ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_full_scans); 512ba76149fSAndrea Arcangeli } 513ba76149fSAndrea Arcangeli static struct kobj_attribute full_scans_attr = 514ba76149fSAndrea Arcangeli __ATTR_RO(full_scans); 515ba76149fSAndrea Arcangeli 516ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_show(struct kobject *kobj, 517ba76149fSAndrea Arcangeli struct kobj_attribute *attr, char *buf) 518ba76149fSAndrea Arcangeli { 519ba76149fSAndrea Arcangeli return single_flag_show(kobj, attr, buf, 520ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 521ba76149fSAndrea Arcangeli } 522ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_store(struct kobject *kobj, 523ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 524ba76149fSAndrea Arcangeli const char *buf, size_t count) 525ba76149fSAndrea Arcangeli { 526ba76149fSAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 527ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 528ba76149fSAndrea Arcangeli } 529ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_defrag_attr = 530ba76149fSAndrea Arcangeli __ATTR(defrag, 0644, khugepaged_defrag_show, 531ba76149fSAndrea Arcangeli khugepaged_defrag_store); 532ba76149fSAndrea Arcangeli 533ba76149fSAndrea Arcangeli /* 534ba76149fSAndrea Arcangeli * max_ptes_none controls if khugepaged should collapse hugepages over 535ba76149fSAndrea Arcangeli * any unmapped ptes in turn potentially increasing the memory 536ba76149fSAndrea Arcangeli * footprint of the vmas. When max_ptes_none is 0 khugepaged will not 537ba76149fSAndrea Arcangeli * reduce the available free memory in the system as it 538ba76149fSAndrea Arcangeli * runs. Increasing max_ptes_none will instead potentially reduce the 539ba76149fSAndrea Arcangeli * free memory in the system during the khugepaged scan. 540ba76149fSAndrea Arcangeli */ 541ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, 542ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 543ba76149fSAndrea Arcangeli char *buf) 544ba76149fSAndrea Arcangeli { 545ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_max_ptes_none); 546ba76149fSAndrea Arcangeli } 547ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, 548ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 549ba76149fSAndrea Arcangeli const char *buf, size_t count) 550ba76149fSAndrea Arcangeli { 551ba76149fSAndrea Arcangeli int err; 552ba76149fSAndrea Arcangeli unsigned long max_ptes_none; 553ba76149fSAndrea Arcangeli 5543dbb95f7SJingoo Han err = kstrtoul(buf, 10, &max_ptes_none); 555ba76149fSAndrea Arcangeli if (err || max_ptes_none > HPAGE_PMD_NR-1) 556ba76149fSAndrea Arcangeli return -EINVAL; 557ba76149fSAndrea Arcangeli 558ba76149fSAndrea Arcangeli khugepaged_max_ptes_none = max_ptes_none; 559ba76149fSAndrea Arcangeli 560ba76149fSAndrea Arcangeli return count; 561ba76149fSAndrea Arcangeli } 562ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_max_ptes_none_attr = 563ba76149fSAndrea Arcangeli __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, 564ba76149fSAndrea Arcangeli khugepaged_max_ptes_none_store); 565ba76149fSAndrea Arcangeli 566ba76149fSAndrea Arcangeli static struct attribute *khugepaged_attr[] = { 567ba76149fSAndrea Arcangeli &khugepaged_defrag_attr.attr, 568ba76149fSAndrea Arcangeli &khugepaged_max_ptes_none_attr.attr, 569ba76149fSAndrea Arcangeli &pages_to_scan_attr.attr, 570ba76149fSAndrea Arcangeli &pages_collapsed_attr.attr, 571ba76149fSAndrea Arcangeli &full_scans_attr.attr, 572ba76149fSAndrea Arcangeli &scan_sleep_millisecs_attr.attr, 573ba76149fSAndrea Arcangeli &alloc_sleep_millisecs_attr.attr, 574ba76149fSAndrea Arcangeli NULL, 575ba76149fSAndrea Arcangeli }; 576ba76149fSAndrea Arcangeli 577ba76149fSAndrea Arcangeli static struct attribute_group khugepaged_attr_group = { 578ba76149fSAndrea Arcangeli .attrs = khugepaged_attr, 579ba76149fSAndrea Arcangeli .name = "khugepaged", 58071e3aac0SAndrea Arcangeli }; 581569e5590SShaohua Li 582569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 583569e5590SShaohua Li { 584569e5590SShaohua Li int err; 585569e5590SShaohua Li 586569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 587569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 588ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 589569e5590SShaohua Li return -ENOMEM; 590569e5590SShaohua Li } 591569e5590SShaohua Li 592569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 593569e5590SShaohua Li if (err) { 594ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 595569e5590SShaohua Li goto delete_obj; 596569e5590SShaohua Li } 597569e5590SShaohua Li 598569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 599569e5590SShaohua Li if (err) { 600ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 601569e5590SShaohua Li goto remove_hp_group; 602569e5590SShaohua Li } 603569e5590SShaohua Li 604569e5590SShaohua Li return 0; 605569e5590SShaohua Li 606569e5590SShaohua Li remove_hp_group: 607569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 608569e5590SShaohua Li delete_obj: 609569e5590SShaohua Li kobject_put(*hugepage_kobj); 610569e5590SShaohua Li return err; 611569e5590SShaohua Li } 612569e5590SShaohua Li 613569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 614569e5590SShaohua Li { 615569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 616569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 617569e5590SShaohua Li kobject_put(hugepage_kobj); 618569e5590SShaohua Li } 619569e5590SShaohua Li #else 620569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 621569e5590SShaohua Li { 622569e5590SShaohua Li return 0; 623569e5590SShaohua Li } 624569e5590SShaohua Li 625569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 626569e5590SShaohua Li { 627569e5590SShaohua Li } 62871e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 62971e3aac0SAndrea Arcangeli 63071e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 63171e3aac0SAndrea Arcangeli { 63271e3aac0SAndrea Arcangeli int err; 633569e5590SShaohua Li struct kobject *hugepage_kobj; 63471e3aac0SAndrea Arcangeli 6354b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 6364b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 637569e5590SShaohua Li return -EINVAL; 6384b7167b9SAndrea Arcangeli } 6394b7167b9SAndrea Arcangeli 640569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 641569e5590SShaohua Li if (err) 642569e5590SShaohua Li return err; 643ba76149fSAndrea Arcangeli 644ba76149fSAndrea Arcangeli err = khugepaged_slab_init(); 645ba76149fSAndrea Arcangeli if (err) 646ba76149fSAndrea Arcangeli goto out; 647ba76149fSAndrea Arcangeli 64897ae1749SKirill A. Shutemov register_shrinker(&huge_zero_page_shrinker); 64997ae1749SKirill A. Shutemov 65097562cd2SRik van Riel /* 65197562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 65297562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 65397562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 65497562cd2SRik van Riel */ 65597562cd2SRik van Riel if (totalram_pages < (512 << (20 - PAGE_SHIFT))) 65697562cd2SRik van Riel transparent_hugepage_flags = 0; 65797562cd2SRik van Riel 658ba76149fSAndrea Arcangeli start_khugepaged(); 659ba76149fSAndrea Arcangeli 660569e5590SShaohua Li return 0; 661ba76149fSAndrea Arcangeli out: 662569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 663ba76149fSAndrea Arcangeli return err; 66471e3aac0SAndrea Arcangeli } 665a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 66671e3aac0SAndrea Arcangeli 66771e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 66871e3aac0SAndrea Arcangeli { 66971e3aac0SAndrea Arcangeli int ret = 0; 67071e3aac0SAndrea Arcangeli if (!str) 67171e3aac0SAndrea Arcangeli goto out; 67271e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 67371e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 67471e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 67571e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 67671e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 67771e3aac0SAndrea Arcangeli ret = 1; 67871e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 67971e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 68071e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 68171e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 68271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 68371e3aac0SAndrea Arcangeli ret = 1; 68471e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 68571e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 68671e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 68771e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 68871e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 68971e3aac0SAndrea Arcangeli ret = 1; 69071e3aac0SAndrea Arcangeli } 69171e3aac0SAndrea Arcangeli out: 69271e3aac0SAndrea Arcangeli if (!ret) 693ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 69471e3aac0SAndrea Arcangeli return ret; 69571e3aac0SAndrea Arcangeli } 69671e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 69771e3aac0SAndrea Arcangeli 698b32967ffSMel Gorman pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 69971e3aac0SAndrea Arcangeli { 70071e3aac0SAndrea Arcangeli if (likely(vma->vm_flags & VM_WRITE)) 70171e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 70271e3aac0SAndrea Arcangeli return pmd; 70371e3aac0SAndrea Arcangeli } 70471e3aac0SAndrea Arcangeli 7053122359aSKirill A. Shutemov static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot) 706b3092b3bSBob Liu { 707b3092b3bSBob Liu pmd_t entry; 7083122359aSKirill A. Shutemov entry = mk_pmd(page, prot); 709b3092b3bSBob Liu entry = pmd_mkhuge(entry); 710b3092b3bSBob Liu return entry; 711b3092b3bSBob Liu } 712b3092b3bSBob Liu 71371e3aac0SAndrea Arcangeli static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, 71471e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 71571e3aac0SAndrea Arcangeli unsigned long haddr, pmd_t *pmd, 71671e3aac0SAndrea Arcangeli struct page *page) 71771e3aac0SAndrea Arcangeli { 71871e3aac0SAndrea Arcangeli pgtable_t pgtable; 719c4088ebdSKirill A. Shutemov spinlock_t *ptl; 72071e3aac0SAndrea Arcangeli 721309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 72271e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(mm, haddr); 723edad9d2cSDavid Rientjes if (unlikely(!pgtable)) 72471e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 72571e3aac0SAndrea Arcangeli 72671e3aac0SAndrea Arcangeli clear_huge_page(page, haddr, HPAGE_PMD_NR); 72752f37629SMinchan Kim /* 72852f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 72952f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 73052f37629SMinchan Kim * write. 73152f37629SMinchan Kim */ 73271e3aac0SAndrea Arcangeli __SetPageUptodate(page); 73371e3aac0SAndrea Arcangeli 734c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 73571e3aac0SAndrea Arcangeli if (unlikely(!pmd_none(*pmd))) { 736c4088ebdSKirill A. Shutemov spin_unlock(ptl); 737b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(page); 73871e3aac0SAndrea Arcangeli put_page(page); 73971e3aac0SAndrea Arcangeli pte_free(mm, pgtable); 74071e3aac0SAndrea Arcangeli } else { 74171e3aac0SAndrea Arcangeli pmd_t entry; 7423122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 7433122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 74471e3aac0SAndrea Arcangeli page_add_new_anon_rmap(page, vma, haddr); 7456b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 74671e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 74771e3aac0SAndrea Arcangeli add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 748e1f56c89SKirill A. Shutemov atomic_long_inc(&mm->nr_ptes); 749c4088ebdSKirill A. Shutemov spin_unlock(ptl); 75071e3aac0SAndrea Arcangeli } 75171e3aac0SAndrea Arcangeli 752aa2e878eSDavid Rientjes return 0; 75371e3aac0SAndrea Arcangeli } 75471e3aac0SAndrea Arcangeli 755cc5d462fSAndi Kleen static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) 7560bbbc0b3SAndrea Arcangeli { 757cc5d462fSAndi Kleen return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; 7580bbbc0b3SAndrea Arcangeli } 7590bbbc0b3SAndrea Arcangeli 7600bbbc0b3SAndrea Arcangeli static inline struct page *alloc_hugepage_vma(int defrag, 7610bbbc0b3SAndrea Arcangeli struct vm_area_struct *vma, 762cc5d462fSAndi Kleen unsigned long haddr, int nd, 763cc5d462fSAndi Kleen gfp_t extra_gfp) 7640bbbc0b3SAndrea Arcangeli { 765cc5d462fSAndi Kleen return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), 7665c4b4be3SAndi Kleen HPAGE_PMD_ORDER, vma, haddr, nd); 7670bbbc0b3SAndrea Arcangeli } 7680bbbc0b3SAndrea Arcangeli 769c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 7703ea41e62SKirill A. Shutemov static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 77197ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 7725918d10aSKirill A. Shutemov struct page *zero_page) 773fc9fe822SKirill A. Shutemov { 774fc9fe822SKirill A. Shutemov pmd_t entry; 7753ea41e62SKirill A. Shutemov if (!pmd_none(*pmd)) 7763ea41e62SKirill A. Shutemov return false; 7775918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 778fc9fe822SKirill A. Shutemov entry = pmd_wrprotect(entry); 779fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 7806b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 781fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 782e1f56c89SKirill A. Shutemov atomic_long_inc(&mm->nr_ptes); 7833ea41e62SKirill A. Shutemov return true; 784fc9fe822SKirill A. Shutemov } 785fc9fe822SKirill A. Shutemov 78671e3aac0SAndrea Arcangeli int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 78771e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, 78871e3aac0SAndrea Arcangeli unsigned int flags) 78971e3aac0SAndrea Arcangeli { 79071e3aac0SAndrea Arcangeli struct page *page; 79171e3aac0SAndrea Arcangeli unsigned long haddr = address & HPAGE_PMD_MASK; 79271e3aac0SAndrea Arcangeli 793128ec037SKirill A. Shutemov if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) 794c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 79571e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 79671e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 797ba76149fSAndrea Arcangeli if (unlikely(khugepaged_enter(vma))) 798ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 79979da5407SKirill A. Shutemov if (!(flags & FAULT_FLAG_WRITE) && 80079da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 801c4088ebdSKirill A. Shutemov spinlock_t *ptl; 80280371957SKirill A. Shutemov pgtable_t pgtable; 8035918d10aSKirill A. Shutemov struct page *zero_page; 8043ea41e62SKirill A. Shutemov bool set; 80580371957SKirill A. Shutemov pgtable = pte_alloc_one(mm, haddr); 80680371957SKirill A. Shutemov if (unlikely(!pgtable)) 80780371957SKirill A. Shutemov return VM_FAULT_OOM; 8085918d10aSKirill A. Shutemov zero_page = get_huge_zero_page(); 8095918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 81097ae1749SKirill A. Shutemov pte_free(mm, pgtable); 81197ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 812c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 81397ae1749SKirill A. Shutemov } 814c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 8153ea41e62SKirill A. Shutemov set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd, 8165918d10aSKirill A. Shutemov zero_page); 817c4088ebdSKirill A. Shutemov spin_unlock(ptl); 8183ea41e62SKirill A. Shutemov if (!set) { 8193ea41e62SKirill A. Shutemov pte_free(mm, pgtable); 8203ea41e62SKirill A. Shutemov put_huge_zero_page(); 8213ea41e62SKirill A. Shutemov } 82280371957SKirill A. Shutemov return 0; 82380371957SKirill A. Shutemov } 8240bbbc0b3SAndrea Arcangeli page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), 825cc5d462fSAndi Kleen vma, haddr, numa_node_id(), 0); 82681ab4201SAndi Kleen if (unlikely(!page)) { 82781ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 828c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 82981ab4201SAndi Kleen } 830d715ae08SMichal Hocko if (unlikely(mem_cgroup_charge_anon(page, mm, GFP_KERNEL))) { 831b9bbfbe3SAndrea Arcangeli put_page(page); 83217766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 833c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 834b9bbfbe3SAndrea Arcangeli } 835128ec037SKirill A. Shutemov if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page))) { 836edad9d2cSDavid Rientjes mem_cgroup_uncharge_page(page); 837edad9d2cSDavid Rientjes put_page(page); 83817766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 839c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 840edad9d2cSDavid Rientjes } 84171e3aac0SAndrea Arcangeli 84217766ddeSDavid Rientjes count_vm_event(THP_FAULT_ALLOC); 843edad9d2cSDavid Rientjes return 0; 84471e3aac0SAndrea Arcangeli } 84571e3aac0SAndrea Arcangeli 84671e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 84771e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 84871e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 84971e3aac0SAndrea Arcangeli { 850c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 85171e3aac0SAndrea Arcangeli struct page *src_page; 85271e3aac0SAndrea Arcangeli pmd_t pmd; 85371e3aac0SAndrea Arcangeli pgtable_t pgtable; 85471e3aac0SAndrea Arcangeli int ret; 85571e3aac0SAndrea Arcangeli 85671e3aac0SAndrea Arcangeli ret = -ENOMEM; 85771e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(dst_mm, addr); 85871e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 85971e3aac0SAndrea Arcangeli goto out; 86071e3aac0SAndrea Arcangeli 861c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 862c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 863c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 86471e3aac0SAndrea Arcangeli 86571e3aac0SAndrea Arcangeli ret = -EAGAIN; 86671e3aac0SAndrea Arcangeli pmd = *src_pmd; 86771e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(pmd))) { 86871e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 86971e3aac0SAndrea Arcangeli goto out_unlock; 87071e3aac0SAndrea Arcangeli } 871fc9fe822SKirill A. Shutemov /* 872c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 873fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 874fc9fe822SKirill A. Shutemov * a page table. 875fc9fe822SKirill A. Shutemov */ 876fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 8775918d10aSKirill A. Shutemov struct page *zero_page; 8783ea41e62SKirill A. Shutemov bool set; 87997ae1749SKirill A. Shutemov /* 88097ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 88197ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 88297ae1749SKirill A. Shutemov * reference. 88397ae1749SKirill A. Shutemov */ 8845918d10aSKirill A. Shutemov zero_page = get_huge_zero_page(); 8853ea41e62SKirill A. Shutemov set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, 8865918d10aSKirill A. Shutemov zero_page); 8873ea41e62SKirill A. Shutemov BUG_ON(!set); /* unexpected !pmd_none(dst_pmd) */ 888fc9fe822SKirill A. Shutemov ret = 0; 889fc9fe822SKirill A. Shutemov goto out_unlock; 890fc9fe822SKirill A. Shutemov } 891de466bd6SMel Gorman 89271e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_splitting(pmd))) { 89371e3aac0SAndrea Arcangeli /* split huge page running from under us */ 894c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 895c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 89671e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 89771e3aac0SAndrea Arcangeli 89871e3aac0SAndrea Arcangeli wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ 89971e3aac0SAndrea Arcangeli goto out; 90071e3aac0SAndrea Arcangeli } 90171e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 902309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 90371e3aac0SAndrea Arcangeli get_page(src_page); 90471e3aac0SAndrea Arcangeli page_dup_rmap(src_page); 90571e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 90671e3aac0SAndrea Arcangeli 90771e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 90871e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 9096b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 91071e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 911e1f56c89SKirill A. Shutemov atomic_long_inc(&dst_mm->nr_ptes); 91271e3aac0SAndrea Arcangeli 91371e3aac0SAndrea Arcangeli ret = 0; 91471e3aac0SAndrea Arcangeli out_unlock: 915c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 916c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 91771e3aac0SAndrea Arcangeli out: 91871e3aac0SAndrea Arcangeli return ret; 91971e3aac0SAndrea Arcangeli } 92071e3aac0SAndrea Arcangeli 921a1dd450bSWill Deacon void huge_pmd_set_accessed(struct mm_struct *mm, 922a1dd450bSWill Deacon struct vm_area_struct *vma, 923a1dd450bSWill Deacon unsigned long address, 924a1dd450bSWill Deacon pmd_t *pmd, pmd_t orig_pmd, 925a1dd450bSWill Deacon int dirty) 926a1dd450bSWill Deacon { 927c4088ebdSKirill A. Shutemov spinlock_t *ptl; 928a1dd450bSWill Deacon pmd_t entry; 929a1dd450bSWill Deacon unsigned long haddr; 930a1dd450bSWill Deacon 931c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 932a1dd450bSWill Deacon if (unlikely(!pmd_same(*pmd, orig_pmd))) 933a1dd450bSWill Deacon goto unlock; 934a1dd450bSWill Deacon 935a1dd450bSWill Deacon entry = pmd_mkyoung(orig_pmd); 936a1dd450bSWill Deacon haddr = address & HPAGE_PMD_MASK; 937a1dd450bSWill Deacon if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) 938a1dd450bSWill Deacon update_mmu_cache_pmd(vma, address, pmd); 939a1dd450bSWill Deacon 940a1dd450bSWill Deacon unlock: 941c4088ebdSKirill A. Shutemov spin_unlock(ptl); 942a1dd450bSWill Deacon } 943a1dd450bSWill Deacon 9445338a937SHugh Dickins /* 9455338a937SHugh Dickins * Save CONFIG_DEBUG_PAGEALLOC from faulting falsely on tail pages 9465338a937SHugh Dickins * during copy_user_huge_page()'s copy_page_rep(): in the case when 9475338a937SHugh Dickins * the source page gets split and a tail freed before copy completes. 9485338a937SHugh Dickins * Called under pmd_lock of checked pmd, so safe from splitting itself. 9495338a937SHugh Dickins */ 9505338a937SHugh Dickins static void get_user_huge_page(struct page *page) 9515338a937SHugh Dickins { 9525338a937SHugh Dickins if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) { 9535338a937SHugh Dickins struct page *endpage = page + HPAGE_PMD_NR; 9545338a937SHugh Dickins 9555338a937SHugh Dickins atomic_add(HPAGE_PMD_NR, &page->_count); 9565338a937SHugh Dickins while (++page < endpage) 9575338a937SHugh Dickins get_huge_page_tail(page); 9585338a937SHugh Dickins } else { 9595338a937SHugh Dickins get_page(page); 9605338a937SHugh Dickins } 9615338a937SHugh Dickins } 9625338a937SHugh Dickins 9635338a937SHugh Dickins static void put_user_huge_page(struct page *page) 9645338a937SHugh Dickins { 9655338a937SHugh Dickins if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) { 9665338a937SHugh Dickins struct page *endpage = page + HPAGE_PMD_NR; 9675338a937SHugh Dickins 9685338a937SHugh Dickins while (page < endpage) 9695338a937SHugh Dickins put_page(page++); 9705338a937SHugh Dickins } else { 9715338a937SHugh Dickins put_page(page); 9725338a937SHugh Dickins } 9735338a937SHugh Dickins } 9745338a937SHugh Dickins 97571e3aac0SAndrea Arcangeli static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, 97671e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 97771e3aac0SAndrea Arcangeli unsigned long address, 97871e3aac0SAndrea Arcangeli pmd_t *pmd, pmd_t orig_pmd, 97971e3aac0SAndrea Arcangeli struct page *page, 98071e3aac0SAndrea Arcangeli unsigned long haddr) 98171e3aac0SAndrea Arcangeli { 982c4088ebdSKirill A. Shutemov spinlock_t *ptl; 98371e3aac0SAndrea Arcangeli pgtable_t pgtable; 98471e3aac0SAndrea Arcangeli pmd_t _pmd; 98571e3aac0SAndrea Arcangeli int ret = 0, i; 98671e3aac0SAndrea Arcangeli struct page **pages; 9872ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 9882ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 98971e3aac0SAndrea Arcangeli 99071e3aac0SAndrea Arcangeli pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, 99171e3aac0SAndrea Arcangeli GFP_KERNEL); 99271e3aac0SAndrea Arcangeli if (unlikely(!pages)) { 99371e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 99471e3aac0SAndrea Arcangeli goto out; 99571e3aac0SAndrea Arcangeli } 99671e3aac0SAndrea Arcangeli 99771e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 998cc5d462fSAndi Kleen pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | 999cc5d462fSAndi Kleen __GFP_OTHER_NODE, 100019ee151eSAndi Kleen vma, address, page_to_nid(page)); 1001b9bbfbe3SAndrea Arcangeli if (unlikely(!pages[i] || 1002d715ae08SMichal Hocko mem_cgroup_charge_anon(pages[i], mm, 1003b9bbfbe3SAndrea Arcangeli GFP_KERNEL))) { 1004b9bbfbe3SAndrea Arcangeli if (pages[i]) 100571e3aac0SAndrea Arcangeli put_page(pages[i]); 1006b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_start(); 1007b9bbfbe3SAndrea Arcangeli while (--i >= 0) { 1008b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(pages[i]); 1009b9bbfbe3SAndrea Arcangeli put_page(pages[i]); 1010b9bbfbe3SAndrea Arcangeli } 1011b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_end(); 101271e3aac0SAndrea Arcangeli kfree(pages); 101371e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 101471e3aac0SAndrea Arcangeli goto out; 101571e3aac0SAndrea Arcangeli } 101671e3aac0SAndrea Arcangeli } 101771e3aac0SAndrea Arcangeli 101871e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 101971e3aac0SAndrea Arcangeli copy_user_highpage(pages[i], page + i, 10200089e485SHillf Danton haddr + PAGE_SIZE * i, vma); 102171e3aac0SAndrea Arcangeli __SetPageUptodate(pages[i]); 102271e3aac0SAndrea Arcangeli cond_resched(); 102371e3aac0SAndrea Arcangeli } 102471e3aac0SAndrea Arcangeli 10252ec74c3eSSagi Grimberg mmun_start = haddr; 10262ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 10272ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 10282ec74c3eSSagi Grimberg 1029c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 103071e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 103171e3aac0SAndrea Arcangeli goto out_free_pages; 1032309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 103371e3aac0SAndrea Arcangeli 10342ec74c3eSSagi Grimberg pmdp_clear_flush(vma, haddr, pmd); 103571e3aac0SAndrea Arcangeli /* leave pmd empty until pte is filled */ 103671e3aac0SAndrea Arcangeli 10376b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 103871e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 103971e3aac0SAndrea Arcangeli 104071e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 104171e3aac0SAndrea Arcangeli pte_t *pte, entry; 104271e3aac0SAndrea Arcangeli entry = mk_pte(pages[i], vma->vm_page_prot); 104371e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 104471e3aac0SAndrea Arcangeli page_add_new_anon_rmap(pages[i], vma, haddr); 104571e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 104671e3aac0SAndrea Arcangeli VM_BUG_ON(!pte_none(*pte)); 104771e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 104871e3aac0SAndrea Arcangeli pte_unmap(pte); 104971e3aac0SAndrea Arcangeli } 105071e3aac0SAndrea Arcangeli kfree(pages); 105171e3aac0SAndrea Arcangeli 105271e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 105371e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 105471e3aac0SAndrea Arcangeli page_remove_rmap(page); 1055c4088ebdSKirill A. Shutemov spin_unlock(ptl); 105671e3aac0SAndrea Arcangeli 10572ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 10582ec74c3eSSagi Grimberg 105971e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 106071e3aac0SAndrea Arcangeli put_page(page); 106171e3aac0SAndrea Arcangeli 106271e3aac0SAndrea Arcangeli out: 106371e3aac0SAndrea Arcangeli return ret; 106471e3aac0SAndrea Arcangeli 106571e3aac0SAndrea Arcangeli out_free_pages: 1066c4088ebdSKirill A. Shutemov spin_unlock(ptl); 10672ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 1068b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_start(); 1069b9bbfbe3SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 1070b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(pages[i]); 107171e3aac0SAndrea Arcangeli put_page(pages[i]); 1072b9bbfbe3SAndrea Arcangeli } 1073b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_end(); 107471e3aac0SAndrea Arcangeli kfree(pages); 107571e3aac0SAndrea Arcangeli goto out; 107671e3aac0SAndrea Arcangeli } 107771e3aac0SAndrea Arcangeli 107871e3aac0SAndrea Arcangeli int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 107971e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, pmd_t orig_pmd) 108071e3aac0SAndrea Arcangeli { 1081c4088ebdSKirill A. Shutemov spinlock_t *ptl; 108271e3aac0SAndrea Arcangeli int ret = 0; 108393b4796dSKirill A. Shutemov struct page *page = NULL, *new_page; 108471e3aac0SAndrea Arcangeli unsigned long haddr; 10852ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 10862ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 108771e3aac0SAndrea Arcangeli 1088c4088ebdSKirill A. Shutemov ptl = pmd_lockptr(mm, pmd); 108971e3aac0SAndrea Arcangeli VM_BUG_ON(!vma->anon_vma); 109093b4796dSKirill A. Shutemov haddr = address & HPAGE_PMD_MASK; 109193b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 109293b4796dSKirill A. Shutemov goto alloc; 1093c4088ebdSKirill A. Shutemov spin_lock(ptl); 109471e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 109571e3aac0SAndrea Arcangeli goto out_unlock; 109671e3aac0SAndrea Arcangeli 109771e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 1098309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); 109971e3aac0SAndrea Arcangeli if (page_mapcount(page) == 1) { 110071e3aac0SAndrea Arcangeli pmd_t entry; 110171e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 110271e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 110371e3aac0SAndrea Arcangeli if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) 1104b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 110571e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 110671e3aac0SAndrea Arcangeli goto out_unlock; 110771e3aac0SAndrea Arcangeli } 11085338a937SHugh Dickins get_user_huge_page(page); 1109c4088ebdSKirill A. Shutemov spin_unlock(ptl); 111093b4796dSKirill A. Shutemov alloc: 111171e3aac0SAndrea Arcangeli if (transparent_hugepage_enabled(vma) && 111271e3aac0SAndrea Arcangeli !transparent_hugepage_debug_cow()) 11130bbbc0b3SAndrea Arcangeli new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), 1114cc5d462fSAndi Kleen vma, haddr, numa_node_id(), 0); 111571e3aac0SAndrea Arcangeli else 111671e3aac0SAndrea Arcangeli new_page = NULL; 111771e3aac0SAndrea Arcangeli 111871e3aac0SAndrea Arcangeli if (unlikely(!new_page)) { 1119eecc1e42SHugh Dickins if (!page) { 1120e9b71ca9SKirill A. Shutemov split_huge_page_pmd(vma, address, pmd); 1121e9b71ca9SKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 112293b4796dSKirill A. Shutemov } else { 112371e3aac0SAndrea Arcangeli ret = do_huge_pmd_wp_page_fallback(mm, vma, address, 112471e3aac0SAndrea Arcangeli pmd, orig_pmd, page, haddr); 11259845cbbdSKirill A. Shutemov if (ret & VM_FAULT_OOM) { 11261f1d06c3SDavid Rientjes split_huge_page(page); 11279845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 11289845cbbdSKirill A. Shutemov } 11295338a937SHugh Dickins put_user_huge_page(page); 113093b4796dSKirill A. Shutemov } 113117766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 113271e3aac0SAndrea Arcangeli goto out; 113371e3aac0SAndrea Arcangeli } 113471e3aac0SAndrea Arcangeli 1135d715ae08SMichal Hocko if (unlikely(mem_cgroup_charge_anon(new_page, mm, GFP_KERNEL))) { 1136b9bbfbe3SAndrea Arcangeli put_page(new_page); 113793b4796dSKirill A. Shutemov if (page) { 11381f1d06c3SDavid Rientjes split_huge_page(page); 11395338a937SHugh Dickins put_user_huge_page(page); 11409845cbbdSKirill A. Shutemov } else 11419845cbbdSKirill A. Shutemov split_huge_page_pmd(vma, address, pmd); 11429845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 114317766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 1144b9bbfbe3SAndrea Arcangeli goto out; 1145b9bbfbe3SAndrea Arcangeli } 1146b9bbfbe3SAndrea Arcangeli 114717766ddeSDavid Rientjes count_vm_event(THP_FAULT_ALLOC); 114817766ddeSDavid Rientjes 1149eecc1e42SHugh Dickins if (!page) 115093b4796dSKirill A. Shutemov clear_huge_page(new_page, haddr, HPAGE_PMD_NR); 115193b4796dSKirill A. Shutemov else 115271e3aac0SAndrea Arcangeli copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); 115371e3aac0SAndrea Arcangeli __SetPageUptodate(new_page); 115471e3aac0SAndrea Arcangeli 11552ec74c3eSSagi Grimberg mmun_start = haddr; 11562ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 11572ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 11582ec74c3eSSagi Grimberg 1159c4088ebdSKirill A. Shutemov spin_lock(ptl); 116093b4796dSKirill A. Shutemov if (page) 11615338a937SHugh Dickins put_user_huge_page(page); 1162b9bbfbe3SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) { 1163c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1164b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(new_page); 116571e3aac0SAndrea Arcangeli put_page(new_page); 11662ec74c3eSSagi Grimberg goto out_mn; 1167b9bbfbe3SAndrea Arcangeli } else { 116871e3aac0SAndrea Arcangeli pmd_t entry; 11693122359aSKirill A. Shutemov entry = mk_huge_pmd(new_page, vma->vm_page_prot); 11703122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 11712ec74c3eSSagi Grimberg pmdp_clear_flush(vma, haddr, pmd); 117271e3aac0SAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, haddr); 117371e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 1174b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 1175eecc1e42SHugh Dickins if (!page) { 117693b4796dSKirill A. Shutemov add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 117797ae1749SKirill A. Shutemov put_huge_zero_page(); 117897ae1749SKirill A. Shutemov } else { 1179309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 118071e3aac0SAndrea Arcangeli page_remove_rmap(page); 118171e3aac0SAndrea Arcangeli put_page(page); 118293b4796dSKirill A. Shutemov } 118371e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 118471e3aac0SAndrea Arcangeli } 1185c4088ebdSKirill A. Shutemov spin_unlock(ptl); 11862ec74c3eSSagi Grimberg out_mn: 11872ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 11882ec74c3eSSagi Grimberg out: 11892ec74c3eSSagi Grimberg return ret; 119071e3aac0SAndrea Arcangeli out_unlock: 1191c4088ebdSKirill A. Shutemov spin_unlock(ptl); 119271e3aac0SAndrea Arcangeli return ret; 119371e3aac0SAndrea Arcangeli } 119471e3aac0SAndrea Arcangeli 1195b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 119671e3aac0SAndrea Arcangeli unsigned long addr, 119771e3aac0SAndrea Arcangeli pmd_t *pmd, 119871e3aac0SAndrea Arcangeli unsigned int flags) 119971e3aac0SAndrea Arcangeli { 1200b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 120171e3aac0SAndrea Arcangeli struct page *page = NULL; 120271e3aac0SAndrea Arcangeli 1203c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 120471e3aac0SAndrea Arcangeli 120571e3aac0SAndrea Arcangeli if (flags & FOLL_WRITE && !pmd_write(*pmd)) 120671e3aac0SAndrea Arcangeli goto out; 120771e3aac0SAndrea Arcangeli 120885facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 120985facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 121085facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 121185facf25SKirill A. Shutemov 12122b4847e7SMel Gorman /* Full NUMA hinting faults to serialise migration in fault paths */ 12132b4847e7SMel Gorman if ((flags & FOLL_NUMA) && pmd_numa(*pmd)) 12142b4847e7SMel Gorman goto out; 12152b4847e7SMel Gorman 121671e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 1217309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 121871e3aac0SAndrea Arcangeli if (flags & FOLL_TOUCH) { 121971e3aac0SAndrea Arcangeli pmd_t _pmd; 122071e3aac0SAndrea Arcangeli /* 122171e3aac0SAndrea Arcangeli * We should set the dirty bit only for FOLL_WRITE but 122271e3aac0SAndrea Arcangeli * for now the dirty bit in the pmd is meaningless. 122371e3aac0SAndrea Arcangeli * And if the dirty bit will become meaningful and 122471e3aac0SAndrea Arcangeli * we'll only set it with FOLL_WRITE, an atomic 122571e3aac0SAndrea Arcangeli * set_bit will be required on the pmd to set the 122671e3aac0SAndrea Arcangeli * young bit, instead of the current set_pmd_at. 122771e3aac0SAndrea Arcangeli */ 122871e3aac0SAndrea Arcangeli _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); 12298663890aSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 12308663890aSAneesh Kumar K.V pmd, _pmd, 1)) 12318663890aSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 123271e3aac0SAndrea Arcangeli } 1233b676b293SDavid Rientjes if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { 1234b676b293SDavid Rientjes if (page->mapping && trylock_page(page)) { 1235b676b293SDavid Rientjes lru_add_drain(); 1236b676b293SDavid Rientjes if (page->mapping) 1237b676b293SDavid Rientjes mlock_vma_page(page); 1238b676b293SDavid Rientjes unlock_page(page); 1239b676b293SDavid Rientjes } 1240b676b293SDavid Rientjes } 124171e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1242309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 124371e3aac0SAndrea Arcangeli if (flags & FOLL_GET) 124470b50f94SAndrea Arcangeli get_page_foll(page); 124571e3aac0SAndrea Arcangeli 124671e3aac0SAndrea Arcangeli out: 124771e3aac0SAndrea Arcangeli return page; 124871e3aac0SAndrea Arcangeli } 124971e3aac0SAndrea Arcangeli 1250d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 12514daae3b4SMel Gorman int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, 12524daae3b4SMel Gorman unsigned long addr, pmd_t pmd, pmd_t *pmdp) 1253d10e63f2SMel Gorman { 1254c4088ebdSKirill A. Shutemov spinlock_t *ptl; 1255b8916634SMel Gorman struct anon_vma *anon_vma = NULL; 1256b32967ffSMel Gorman struct page *page; 1257d10e63f2SMel Gorman unsigned long haddr = addr & HPAGE_PMD_MASK; 12588191acbdSMel Gorman int page_nid = -1, this_nid = numa_node_id(); 125990572890SPeter Zijlstra int target_nid, last_cpupid = -1; 12608191acbdSMel Gorman bool page_locked; 12618191acbdSMel Gorman bool migrated = false; 12626688cc05SPeter Zijlstra int flags = 0; 1263d10e63f2SMel Gorman 1264c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmdp); 1265d10e63f2SMel Gorman if (unlikely(!pmd_same(pmd, *pmdp))) 1266d10e63f2SMel Gorman goto out_unlock; 1267d10e63f2SMel Gorman 1268de466bd6SMel Gorman /* 1269de466bd6SMel Gorman * If there are potential migrations, wait for completion and retry 1270de466bd6SMel Gorman * without disrupting NUMA hinting information. Do not relock and 1271de466bd6SMel Gorman * check_same as the page may no longer be mapped. 1272de466bd6SMel Gorman */ 1273de466bd6SMel Gorman if (unlikely(pmd_trans_migrating(*pmdp))) { 1274de466bd6SMel Gorman spin_unlock(ptl); 1275de466bd6SMel Gorman wait_migrate_huge_page(vma->anon_vma, pmdp); 1276de466bd6SMel Gorman goto out; 1277de466bd6SMel Gorman } 1278de466bd6SMel Gorman 1279d10e63f2SMel Gorman page = pmd_page(pmd); 1280a1a46184SMel Gorman BUG_ON(is_huge_zero_page(page)); 12818191acbdSMel Gorman page_nid = page_to_nid(page); 128290572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 128303c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 128404bb2f94SRik van Riel if (page_nid == this_nid) { 128503c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 128604bb2f94SRik van Riel flags |= TNF_FAULT_LOCAL; 128704bb2f94SRik van Riel } 12884daae3b4SMel Gorman 1289ff9042b1SMel Gorman /* 12906688cc05SPeter Zijlstra * Avoid grouping on DSO/COW pages in specific and RO pages 12916688cc05SPeter Zijlstra * in general, RO pages shouldn't hurt as much anyway since 12926688cc05SPeter Zijlstra * they can be in shared cache state. 12936688cc05SPeter Zijlstra */ 12946688cc05SPeter Zijlstra if (!pmd_write(pmd)) 12956688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 12966688cc05SPeter Zijlstra 12976688cc05SPeter Zijlstra /* 1298ff9042b1SMel Gorman * Acquire the page lock to serialise THP migrations but avoid dropping 1299ff9042b1SMel Gorman * page_table_lock if at all possible 1300ff9042b1SMel Gorman */ 1301b8916634SMel Gorman page_locked = trylock_page(page); 1302b8916634SMel Gorman target_nid = mpol_misplaced(page, vma, haddr); 1303b8916634SMel Gorman if (target_nid == -1) { 1304b8916634SMel Gorman /* If the page was locked, there are no parallel migrations */ 1305a54a407fSMel Gorman if (page_locked) 1306b8916634SMel Gorman goto clear_pmdnuma; 13072b4847e7SMel Gorman } 1308cbee9f88SPeter Zijlstra 1309de466bd6SMel Gorman /* Migration could have started since the pmd_trans_migrating check */ 13102b4847e7SMel Gorman if (!page_locked) { 1311c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1312b8916634SMel Gorman wait_on_page_locked(page); 1313a54a407fSMel Gorman page_nid = -1; 1314b8916634SMel Gorman goto out; 1315b8916634SMel Gorman } 1316b8916634SMel Gorman 13172b4847e7SMel Gorman /* 13182b4847e7SMel Gorman * Page is misplaced. Page lock serialises migrations. Acquire anon_vma 13192b4847e7SMel Gorman * to serialises splits 13202b4847e7SMel Gorman */ 1321b8916634SMel Gorman get_page(page); 1322c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1323b8916634SMel Gorman anon_vma = page_lock_anon_vma_read(page); 1324b32967ffSMel Gorman 1325c69307d5SPeter Zijlstra /* Confirm the PMD did not change while page_table_lock was released */ 1326c4088ebdSKirill A. Shutemov spin_lock(ptl); 1327b32967ffSMel Gorman if (unlikely(!pmd_same(pmd, *pmdp))) { 1328b32967ffSMel Gorman unlock_page(page); 1329b32967ffSMel Gorman put_page(page); 1330a54a407fSMel Gorman page_nid = -1; 1331b32967ffSMel Gorman goto out_unlock; 1332b32967ffSMel Gorman } 1333ff9042b1SMel Gorman 1334c3a489caSMel Gorman /* Bail if we fail to protect against THP splits for any reason */ 1335c3a489caSMel Gorman if (unlikely(!anon_vma)) { 1336c3a489caSMel Gorman put_page(page); 1337c3a489caSMel Gorman page_nid = -1; 1338c3a489caSMel Gorman goto clear_pmdnuma; 1339c3a489caSMel Gorman } 1340c3a489caSMel Gorman 1341a54a407fSMel Gorman /* 1342a54a407fSMel Gorman * Migrate the THP to the requested node, returns with page unlocked 1343a54a407fSMel Gorman * and pmd_numa cleared. 1344a54a407fSMel Gorman */ 1345c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1346b32967ffSMel Gorman migrated = migrate_misplaced_transhuge_page(mm, vma, 1347340ef390SHugh Dickins pmdp, pmd, addr, page, target_nid); 13486688cc05SPeter Zijlstra if (migrated) { 13496688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 13508191acbdSMel Gorman page_nid = target_nid; 13516688cc05SPeter Zijlstra } 1352b32967ffSMel Gorman 13538191acbdSMel Gorman goto out; 13544daae3b4SMel Gorman clear_pmdnuma: 1355a54a407fSMel Gorman BUG_ON(!PageLocked(page)); 1356d10e63f2SMel Gorman pmd = pmd_mknonnuma(pmd); 1357d10e63f2SMel Gorman set_pmd_at(mm, haddr, pmdp, pmd); 1358d10e63f2SMel Gorman VM_BUG_ON(pmd_numa(*pmdp)); 1359d10e63f2SMel Gorman update_mmu_cache_pmd(vma, addr, pmdp); 1360a54a407fSMel Gorman unlock_page(page); 1361d10e63f2SMel Gorman out_unlock: 1362c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1363b8916634SMel Gorman 1364b8916634SMel Gorman out: 1365b8916634SMel Gorman if (anon_vma) 1366b8916634SMel Gorman page_unlock_anon_vma_read(anon_vma); 1367b8916634SMel Gorman 13688191acbdSMel Gorman if (page_nid != -1) 13696688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags); 13708191acbdSMel Gorman 1371d10e63f2SMel Gorman return 0; 1372d10e63f2SMel Gorman } 1373d10e63f2SMel Gorman 137471e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1375f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 137671e3aac0SAndrea Arcangeli { 1377bf929152SKirill A. Shutemov spinlock_t *ptl; 137871e3aac0SAndrea Arcangeli int ret = 0; 137971e3aac0SAndrea Arcangeli 1380bf929152SKirill A. Shutemov if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { 138171e3aac0SAndrea Arcangeli struct page *page; 138271e3aac0SAndrea Arcangeli pgtable_t pgtable; 1383f5c8ad47SDavid Miller pmd_t orig_pmd; 1384a6bf2bb0SAneesh Kumar K.V /* 1385a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 1386a6bf2bb0SAneesh Kumar K.V * when calling pmdp_get_and_clear. So do the 1387a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1388a6bf2bb0SAneesh Kumar K.V * operations. 1389a6bf2bb0SAneesh Kumar K.V */ 1390f5c8ad47SDavid Miller orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); 1391f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1392a6bf2bb0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); 1393479f0abbSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) { 1394e1f56c89SKirill A. Shutemov atomic_long_dec(&tlb->mm->nr_ptes); 1395bf929152SKirill A. Shutemov spin_unlock(ptl); 139697ae1749SKirill A. Shutemov put_huge_zero_page(); 1397479f0abbSKirill A. Shutemov } else { 1398479f0abbSKirill A. Shutemov page = pmd_page(orig_pmd); 139971e3aac0SAndrea Arcangeli page_remove_rmap(page); 1400309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 140171e3aac0SAndrea Arcangeli add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1402309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1403e1f56c89SKirill A. Shutemov atomic_long_dec(&tlb->mm->nr_ptes); 1404bf929152SKirill A. Shutemov spin_unlock(ptl); 140571e3aac0SAndrea Arcangeli tlb_remove_page(tlb, page); 1406479f0abbSKirill A. Shutemov } 140771e3aac0SAndrea Arcangeli pte_free(tlb->mm, pgtable); 140871e3aac0SAndrea Arcangeli ret = 1; 140971e3aac0SAndrea Arcangeli } 141071e3aac0SAndrea Arcangeli return ret; 141171e3aac0SAndrea Arcangeli } 141271e3aac0SAndrea Arcangeli 14130ca1634dSJohannes Weiner int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 14140ca1634dSJohannes Weiner unsigned long addr, unsigned long end, 14150ca1634dSJohannes Weiner unsigned char *vec) 14160ca1634dSJohannes Weiner { 1417bf929152SKirill A. Shutemov spinlock_t *ptl; 14180ca1634dSJohannes Weiner int ret = 0; 14190ca1634dSJohannes Weiner 1420bf929152SKirill A. Shutemov if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { 14210ca1634dSJohannes Weiner /* 14220ca1634dSJohannes Weiner * All logical pages in the range are present 14230ca1634dSJohannes Weiner * if backed by a huge page. 14240ca1634dSJohannes Weiner */ 1425bf929152SKirill A. Shutemov spin_unlock(ptl); 1426025c5b24SNaoya Horiguchi memset(vec, 1, (end - addr) >> PAGE_SHIFT); 1427025c5b24SNaoya Horiguchi ret = 1; 1428025c5b24SNaoya Horiguchi } 14290ca1634dSJohannes Weiner 14300ca1634dSJohannes Weiner return ret; 14310ca1634dSJohannes Weiner } 14320ca1634dSJohannes Weiner 143337a1c49aSAndrea Arcangeli int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, 143437a1c49aSAndrea Arcangeli unsigned long old_addr, 143537a1c49aSAndrea Arcangeli unsigned long new_addr, unsigned long old_end, 143637a1c49aSAndrea Arcangeli pmd_t *old_pmd, pmd_t *new_pmd) 143737a1c49aSAndrea Arcangeli { 1438bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 143937a1c49aSAndrea Arcangeli int ret = 0; 144037a1c49aSAndrea Arcangeli pmd_t pmd; 144137a1c49aSAndrea Arcangeli 144237a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 144337a1c49aSAndrea Arcangeli 144437a1c49aSAndrea Arcangeli if ((old_addr & ~HPAGE_PMD_MASK) || 144537a1c49aSAndrea Arcangeli (new_addr & ~HPAGE_PMD_MASK) || 144637a1c49aSAndrea Arcangeli old_end - old_addr < HPAGE_PMD_SIZE || 144737a1c49aSAndrea Arcangeli (new_vma->vm_flags & VM_NOHUGEPAGE)) 144837a1c49aSAndrea Arcangeli goto out; 144937a1c49aSAndrea Arcangeli 145037a1c49aSAndrea Arcangeli /* 145137a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 145237a1c49aSAndrea Arcangeli * should have release it. 145337a1c49aSAndrea Arcangeli */ 145437a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 145537a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 145637a1c49aSAndrea Arcangeli goto out; 145737a1c49aSAndrea Arcangeli } 145837a1c49aSAndrea Arcangeli 1459bf929152SKirill A. Shutemov /* 1460bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1461bf929152SKirill A. Shutemov * ptlocks because exclusive mmap_sem prevents deadlock. 1462bf929152SKirill A. Shutemov */ 1463bf929152SKirill A. Shutemov ret = __pmd_trans_huge_lock(old_pmd, vma, &old_ptl); 1464025c5b24SNaoya Horiguchi if (ret == 1) { 1465bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1466bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1467bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 146837a1c49aSAndrea Arcangeli pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); 146937a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 14703592806cSKirill A. Shutemov 1471b3084f4dSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl)) { 1472b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 14733592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 14743592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 14753592806cSKirill A. Shutemov } 1476b3084f4dSAneesh Kumar K.V set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); 1477b3084f4dSAneesh Kumar K.V if (new_ptl != old_ptl) 1478b3084f4dSAneesh Kumar K.V spin_unlock(new_ptl); 1479bf929152SKirill A. Shutemov spin_unlock(old_ptl); 148037a1c49aSAndrea Arcangeli } 148137a1c49aSAndrea Arcangeli out: 148237a1c49aSAndrea Arcangeli return ret; 148337a1c49aSAndrea Arcangeli } 148437a1c49aSAndrea Arcangeli 1485f123d74aSMel Gorman /* 1486f123d74aSMel Gorman * Returns 1487f123d74aSMel Gorman * - 0 if PMD could not be locked 1488f123d74aSMel Gorman * - 1 if PMD was locked but protections unchange and TLB flush unnecessary 1489f123d74aSMel Gorman * - HPAGE_PMD_NR is protections changed and TLB flush necessary 1490f123d74aSMel Gorman */ 1491cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 14924b10e7d5SMel Gorman unsigned long addr, pgprot_t newprot, int prot_numa) 1493cd7548abSJohannes Weiner { 1494cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1495bf929152SKirill A. Shutemov spinlock_t *ptl; 1496cd7548abSJohannes Weiner int ret = 0; 1497cd7548abSJohannes Weiner 1498bf929152SKirill A. Shutemov if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { 1499cd7548abSJohannes Weiner pmd_t entry; 1500f123d74aSMel Gorman ret = 1; 1501a4f1de17SHugh Dickins if (!prot_numa) { 1502f123d74aSMel Gorman entry = pmdp_get_and_clear(mm, addr, pmd); 15031667918bSMel Gorman if (pmd_numa(entry)) 15041667918bSMel Gorman entry = pmd_mknonnuma(entry); 1505cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 1506f123d74aSMel Gorman ret = HPAGE_PMD_NR; 150756eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 1508a4f1de17SHugh Dickins BUG_ON(pmd_write(entry)); 1509a4f1de17SHugh Dickins } else { 15104b10e7d5SMel Gorman struct page *page = pmd_page(*pmd); 15114b10e7d5SMel Gorman 1512a1a46184SMel Gorman /* 15131bc115d8SMel Gorman * Do not trap faults against the zero page. The 15141bc115d8SMel Gorman * read-only data is likely to be read-cached on the 15151bc115d8SMel Gorman * local CPU cache and it is less useful to know about 15161bc115d8SMel Gorman * local vs remote hits on the zero page. 1517a1a46184SMel Gorman */ 15181bc115d8SMel Gorman if (!is_huge_zero_page(page) && 15194b10e7d5SMel Gorman !pmd_numa(*pmd)) { 152056eecdb9SAneesh Kumar K.V pmdp_set_numa(mm, addr, pmd); 1521f123d74aSMel Gorman ret = HPAGE_PMD_NR; 15224b10e7d5SMel Gorman } 15234b10e7d5SMel Gorman } 1524bf929152SKirill A. Shutemov spin_unlock(ptl); 1525cd7548abSJohannes Weiner } 1526cd7548abSJohannes Weiner 1527cd7548abSJohannes Weiner return ret; 1528cd7548abSJohannes Weiner } 1529cd7548abSJohannes Weiner 1530025c5b24SNaoya Horiguchi /* 1531025c5b24SNaoya Horiguchi * Returns 1 if a given pmd maps a stable (not under splitting) thp. 1532025c5b24SNaoya Horiguchi * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. 1533025c5b24SNaoya Horiguchi * 1534025c5b24SNaoya Horiguchi * Note that if it returns 1, this routine returns without unlocking page 1535025c5b24SNaoya Horiguchi * table locks. So callers must unlock them. 1536025c5b24SNaoya Horiguchi */ 1537bf929152SKirill A. Shutemov int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, 1538bf929152SKirill A. Shutemov spinlock_t **ptl) 1539025c5b24SNaoya Horiguchi { 1540bf929152SKirill A. Shutemov *ptl = pmd_lock(vma->vm_mm, pmd); 1541025c5b24SNaoya Horiguchi if (likely(pmd_trans_huge(*pmd))) { 1542025c5b24SNaoya Horiguchi if (unlikely(pmd_trans_splitting(*pmd))) { 1543bf929152SKirill A. Shutemov spin_unlock(*ptl); 1544025c5b24SNaoya Horiguchi wait_split_huge_page(vma->anon_vma, pmd); 1545025c5b24SNaoya Horiguchi return -1; 1546025c5b24SNaoya Horiguchi } else { 1547025c5b24SNaoya Horiguchi /* Thp mapped by 'pmd' is stable, so we can 1548025c5b24SNaoya Horiguchi * handle it as it is. */ 1549025c5b24SNaoya Horiguchi return 1; 1550025c5b24SNaoya Horiguchi } 1551025c5b24SNaoya Horiguchi } 1552bf929152SKirill A. Shutemov spin_unlock(*ptl); 1553025c5b24SNaoya Horiguchi return 0; 1554025c5b24SNaoya Horiguchi } 1555025c5b24SNaoya Horiguchi 1556117b0791SKirill A. Shutemov /* 1557117b0791SKirill A. Shutemov * This function returns whether a given @page is mapped onto the @address 1558117b0791SKirill A. Shutemov * in the virtual space of @mm. 1559117b0791SKirill A. Shutemov * 1560117b0791SKirill A. Shutemov * When it's true, this function returns *pmd with holding the page table lock 1561117b0791SKirill A. Shutemov * and passing it back to the caller via @ptl. 1562117b0791SKirill A. Shutemov * If it's false, returns NULL without holding the page table lock. 1563117b0791SKirill A. Shutemov */ 156471e3aac0SAndrea Arcangeli pmd_t *page_check_address_pmd(struct page *page, 156571e3aac0SAndrea Arcangeli struct mm_struct *mm, 156671e3aac0SAndrea Arcangeli unsigned long address, 1567117b0791SKirill A. Shutemov enum page_check_address_pmd_flag flag, 1568117b0791SKirill A. Shutemov spinlock_t **ptl) 156971e3aac0SAndrea Arcangeli { 1570b5a8cad3SKirill A. Shutemov pgd_t *pgd; 1571b5a8cad3SKirill A. Shutemov pud_t *pud; 1572117b0791SKirill A. Shutemov pmd_t *pmd; 157371e3aac0SAndrea Arcangeli 157471e3aac0SAndrea Arcangeli if (address & ~HPAGE_PMD_MASK) 1575117b0791SKirill A. Shutemov return NULL; 157671e3aac0SAndrea Arcangeli 1577b5a8cad3SKirill A. Shutemov pgd = pgd_offset(mm, address); 1578b5a8cad3SKirill A. Shutemov if (!pgd_present(*pgd)) 1579117b0791SKirill A. Shutemov return NULL; 1580b5a8cad3SKirill A. Shutemov pud = pud_offset(pgd, address); 1581b5a8cad3SKirill A. Shutemov if (!pud_present(*pud)) 1582b5a8cad3SKirill A. Shutemov return NULL; 1583b5a8cad3SKirill A. Shutemov pmd = pmd_offset(pud, address); 1584b5a8cad3SKirill A. Shutemov 1585117b0791SKirill A. Shutemov *ptl = pmd_lock(mm, pmd); 1586b5a8cad3SKirill A. Shutemov if (!pmd_present(*pmd)) 1587117b0791SKirill A. Shutemov goto unlock; 158871e3aac0SAndrea Arcangeli if (pmd_page(*pmd) != page) 1589117b0791SKirill A. Shutemov goto unlock; 159094fcc585SAndrea Arcangeli /* 159194fcc585SAndrea Arcangeli * split_vma() may create temporary aliased mappings. There is 159294fcc585SAndrea Arcangeli * no risk as long as all huge pmd are found and have their 159394fcc585SAndrea Arcangeli * splitting bit set before __split_huge_page_refcount 159494fcc585SAndrea Arcangeli * runs. Finding the same huge pmd more than once during the 159594fcc585SAndrea Arcangeli * same rmap walk is not a problem. 159694fcc585SAndrea Arcangeli */ 159794fcc585SAndrea Arcangeli if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && 159894fcc585SAndrea Arcangeli pmd_trans_splitting(*pmd)) 1599117b0791SKirill A. Shutemov goto unlock; 160071e3aac0SAndrea Arcangeli if (pmd_trans_huge(*pmd)) { 160171e3aac0SAndrea Arcangeli VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && 160271e3aac0SAndrea Arcangeli !pmd_trans_splitting(*pmd)); 1603117b0791SKirill A. Shutemov return pmd; 160471e3aac0SAndrea Arcangeli } 1605117b0791SKirill A. Shutemov unlock: 1606117b0791SKirill A. Shutemov spin_unlock(*ptl); 1607117b0791SKirill A. Shutemov return NULL; 160871e3aac0SAndrea Arcangeli } 160971e3aac0SAndrea Arcangeli 161071e3aac0SAndrea Arcangeli static int __split_huge_page_splitting(struct page *page, 161171e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 161271e3aac0SAndrea Arcangeli unsigned long address) 161371e3aac0SAndrea Arcangeli { 161471e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 1615117b0791SKirill A. Shutemov spinlock_t *ptl; 161671e3aac0SAndrea Arcangeli pmd_t *pmd; 161771e3aac0SAndrea Arcangeli int ret = 0; 16182ec74c3eSSagi Grimberg /* For mmu_notifiers */ 16192ec74c3eSSagi Grimberg const unsigned long mmun_start = address; 16202ec74c3eSSagi Grimberg const unsigned long mmun_end = address + HPAGE_PMD_SIZE; 162171e3aac0SAndrea Arcangeli 16222ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 162371e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 1624117b0791SKirill A. Shutemov PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG, &ptl); 162571e3aac0SAndrea Arcangeli if (pmd) { 162671e3aac0SAndrea Arcangeli /* 162771e3aac0SAndrea Arcangeli * We can't temporarily set the pmd to null in order 162871e3aac0SAndrea Arcangeli * to split it, the pmd must remain marked huge at all 162971e3aac0SAndrea Arcangeli * times or the VM won't take the pmd_trans_huge paths 16305a505085SIngo Molnar * and it won't wait on the anon_vma->root->rwsem to 163171e3aac0SAndrea Arcangeli * serialize against split_huge_page*. 163271e3aac0SAndrea Arcangeli */ 16332ec74c3eSSagi Grimberg pmdp_splitting_flush(vma, address, pmd); 163471e3aac0SAndrea Arcangeli ret = 1; 1635117b0791SKirill A. Shutemov spin_unlock(ptl); 163671e3aac0SAndrea Arcangeli } 16372ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 163871e3aac0SAndrea Arcangeli 163971e3aac0SAndrea Arcangeli return ret; 164071e3aac0SAndrea Arcangeli } 164171e3aac0SAndrea Arcangeli 16425bc7b8acSShaohua Li static void __split_huge_page_refcount(struct page *page, 16435bc7b8acSShaohua Li struct list_head *list) 164471e3aac0SAndrea Arcangeli { 164571e3aac0SAndrea Arcangeli int i; 164671e3aac0SAndrea Arcangeli struct zone *zone = page_zone(page); 1647fa9add64SHugh Dickins struct lruvec *lruvec; 164870b50f94SAndrea Arcangeli int tail_count = 0; 164971e3aac0SAndrea Arcangeli 165071e3aac0SAndrea Arcangeli /* prevent PageLRU to go away from under us, and freeze lru stats */ 165171e3aac0SAndrea Arcangeli spin_lock_irq(&zone->lru_lock); 1652fa9add64SHugh Dickins lruvec = mem_cgroup_page_lruvec(page, zone); 1653fa9add64SHugh Dickins 165471e3aac0SAndrea Arcangeli compound_lock(page); 1655e94c8a9cSKAMEZAWA Hiroyuki /* complete memcg works before add pages to LRU */ 1656e94c8a9cSKAMEZAWA Hiroyuki mem_cgroup_split_huge_fixup(page); 165771e3aac0SAndrea Arcangeli 165845676885SShaohua Li for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { 165971e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 166071e3aac0SAndrea Arcangeli 166170b50f94SAndrea Arcangeli /* tail_page->_mapcount cannot change */ 166270b50f94SAndrea Arcangeli BUG_ON(page_mapcount(page_tail) < 0); 166370b50f94SAndrea Arcangeli tail_count += page_mapcount(page_tail); 166470b50f94SAndrea Arcangeli /* check for overflow */ 166570b50f94SAndrea Arcangeli BUG_ON(tail_count < 0); 166670b50f94SAndrea Arcangeli BUG_ON(atomic_read(&page_tail->_count) != 0); 166770b50f94SAndrea Arcangeli /* 166870b50f94SAndrea Arcangeli * tail_page->_count is zero and not changing from 166970b50f94SAndrea Arcangeli * under us. But get_page_unless_zero() may be running 167070b50f94SAndrea Arcangeli * from under us on the tail_page. If we used 167170b50f94SAndrea Arcangeli * atomic_set() below instead of atomic_add(), we 167270b50f94SAndrea Arcangeli * would then run atomic_set() concurrently with 167370b50f94SAndrea Arcangeli * get_page_unless_zero(), and atomic_set() is 167470b50f94SAndrea Arcangeli * implemented in C not using locked ops. spin_unlock 167570b50f94SAndrea Arcangeli * on x86 sometime uses locked ops because of PPro 167670b50f94SAndrea Arcangeli * errata 66, 92, so unless somebody can guarantee 167770b50f94SAndrea Arcangeli * atomic_set() here would be safe on all archs (and 167870b50f94SAndrea Arcangeli * not only on x86), it's safer to use atomic_add(). 167970b50f94SAndrea Arcangeli */ 168070b50f94SAndrea Arcangeli atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, 168170b50f94SAndrea Arcangeli &page_tail->_count); 168271e3aac0SAndrea Arcangeli 168371e3aac0SAndrea Arcangeli /* after clearing PageTail the gup refcount can be released */ 168471e3aac0SAndrea Arcangeli smp_mb(); 168571e3aac0SAndrea Arcangeli 1686a6d30dddSJin Dongming /* 1687a6d30dddSJin Dongming * retain hwpoison flag of the poisoned tail page: 1688a6d30dddSJin Dongming * fix for the unsuitable process killed on Guest Machine(KVM) 1689a6d30dddSJin Dongming * by the memory-failure. 1690a6d30dddSJin Dongming */ 1691a6d30dddSJin Dongming page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; 169271e3aac0SAndrea Arcangeli page_tail->flags |= (page->flags & 169371e3aac0SAndrea Arcangeli ((1L << PG_referenced) | 169471e3aac0SAndrea Arcangeli (1L << PG_swapbacked) | 169571e3aac0SAndrea Arcangeli (1L << PG_mlocked) | 1696e180cf80SKirill A. Shutemov (1L << PG_uptodate) | 1697e180cf80SKirill A. Shutemov (1L << PG_active) | 1698e180cf80SKirill A. Shutemov (1L << PG_unevictable))); 169971e3aac0SAndrea Arcangeli page_tail->flags |= (1L << PG_dirty); 170071e3aac0SAndrea Arcangeli 170170b50f94SAndrea Arcangeli /* clear PageTail before overwriting first_page */ 170271e3aac0SAndrea Arcangeli smp_wmb(); 170371e3aac0SAndrea Arcangeli 170471e3aac0SAndrea Arcangeli /* 170571e3aac0SAndrea Arcangeli * __split_huge_page_splitting() already set the 170671e3aac0SAndrea Arcangeli * splitting bit in all pmd that could map this 170771e3aac0SAndrea Arcangeli * hugepage, that will ensure no CPU can alter the 170871e3aac0SAndrea Arcangeli * mapcount on the head page. The mapcount is only 170971e3aac0SAndrea Arcangeli * accounted in the head page and it has to be 171071e3aac0SAndrea Arcangeli * transferred to all tail pages in the below code. So 171171e3aac0SAndrea Arcangeli * for this code to be safe, the split the mapcount 171271e3aac0SAndrea Arcangeli * can't change. But that doesn't mean userland can't 171371e3aac0SAndrea Arcangeli * keep changing and reading the page contents while 171471e3aac0SAndrea Arcangeli * we transfer the mapcount, so the pmd splitting 171571e3aac0SAndrea Arcangeli * status is achieved setting a reserved bit in the 171671e3aac0SAndrea Arcangeli * pmd, not by clearing the present bit. 171771e3aac0SAndrea Arcangeli */ 171871e3aac0SAndrea Arcangeli page_tail->_mapcount = page->_mapcount; 171971e3aac0SAndrea Arcangeli 172071e3aac0SAndrea Arcangeli BUG_ON(page_tail->mapping); 172171e3aac0SAndrea Arcangeli page_tail->mapping = page->mapping; 172271e3aac0SAndrea Arcangeli 172345676885SShaohua Li page_tail->index = page->index + i; 172490572890SPeter Zijlstra page_cpupid_xchg_last(page_tail, page_cpupid_last(page)); 172571e3aac0SAndrea Arcangeli 172671e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page_tail)); 172771e3aac0SAndrea Arcangeli BUG_ON(!PageUptodate(page_tail)); 172871e3aac0SAndrea Arcangeli BUG_ON(!PageDirty(page_tail)); 172971e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page_tail)); 173071e3aac0SAndrea Arcangeli 17315bc7b8acSShaohua Li lru_add_page_tail(page, page_tail, lruvec, list); 173271e3aac0SAndrea Arcangeli } 173370b50f94SAndrea Arcangeli atomic_sub(tail_count, &page->_count); 173470b50f94SAndrea Arcangeli BUG_ON(atomic_read(&page->_count) <= 0); 173571e3aac0SAndrea Arcangeli 1736fa9add64SHugh Dickins __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); 173779134171SAndrea Arcangeli 173871e3aac0SAndrea Arcangeli ClearPageCompound(page); 173971e3aac0SAndrea Arcangeli compound_unlock(page); 174071e3aac0SAndrea Arcangeli spin_unlock_irq(&zone->lru_lock); 174171e3aac0SAndrea Arcangeli 174271e3aac0SAndrea Arcangeli for (i = 1; i < HPAGE_PMD_NR; i++) { 174371e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 174471e3aac0SAndrea Arcangeli BUG_ON(page_count(page_tail) <= 0); 174571e3aac0SAndrea Arcangeli /* 174671e3aac0SAndrea Arcangeli * Tail pages may be freed if there wasn't any mapping 174771e3aac0SAndrea Arcangeli * like if add_to_swap() is running on a lru page that 174871e3aac0SAndrea Arcangeli * had its mapping zapped. And freeing these pages 174971e3aac0SAndrea Arcangeli * requires taking the lru_lock so we do the put_page 175071e3aac0SAndrea Arcangeli * of the tail pages after the split is complete. 175171e3aac0SAndrea Arcangeli */ 175271e3aac0SAndrea Arcangeli put_page(page_tail); 175371e3aac0SAndrea Arcangeli } 175471e3aac0SAndrea Arcangeli 175571e3aac0SAndrea Arcangeli /* 175671e3aac0SAndrea Arcangeli * Only the head page (now become a regular page) is required 175771e3aac0SAndrea Arcangeli * to be pinned by the caller. 175871e3aac0SAndrea Arcangeli */ 175971e3aac0SAndrea Arcangeli BUG_ON(page_count(page) <= 0); 176071e3aac0SAndrea Arcangeli } 176171e3aac0SAndrea Arcangeli 176271e3aac0SAndrea Arcangeli static int __split_huge_page_map(struct page *page, 176371e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 176471e3aac0SAndrea Arcangeli unsigned long address) 176571e3aac0SAndrea Arcangeli { 176671e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 1767117b0791SKirill A. Shutemov spinlock_t *ptl; 176871e3aac0SAndrea Arcangeli pmd_t *pmd, _pmd; 176971e3aac0SAndrea Arcangeli int ret = 0, i; 177071e3aac0SAndrea Arcangeli pgtable_t pgtable; 177171e3aac0SAndrea Arcangeli unsigned long haddr; 177271e3aac0SAndrea Arcangeli 177371e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 1774117b0791SKirill A. Shutemov PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG, &ptl); 177571e3aac0SAndrea Arcangeli if (pmd) { 17766b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 177771e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 177871e3aac0SAndrea Arcangeli 1779e3ebcf64SGerald Schaefer haddr = address; 1780e3ebcf64SGerald Schaefer for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 178171e3aac0SAndrea Arcangeli pte_t *pte, entry; 178271e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page+i)); 178371e3aac0SAndrea Arcangeli entry = mk_pte(page + i, vma->vm_page_prot); 178471e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 178571e3aac0SAndrea Arcangeli if (!pmd_write(*pmd)) 178671e3aac0SAndrea Arcangeli entry = pte_wrprotect(entry); 178771e3aac0SAndrea Arcangeli else 178871e3aac0SAndrea Arcangeli BUG_ON(page_mapcount(page) != 1); 178971e3aac0SAndrea Arcangeli if (!pmd_young(*pmd)) 179071e3aac0SAndrea Arcangeli entry = pte_mkold(entry); 17911ba6e0b5SAndrea Arcangeli if (pmd_numa(*pmd)) 17921ba6e0b5SAndrea Arcangeli entry = pte_mknuma(entry); 179371e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 179471e3aac0SAndrea Arcangeli BUG_ON(!pte_none(*pte)); 179571e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 179671e3aac0SAndrea Arcangeli pte_unmap(pte); 179771e3aac0SAndrea Arcangeli } 179871e3aac0SAndrea Arcangeli 179971e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 180071e3aac0SAndrea Arcangeli /* 180171e3aac0SAndrea Arcangeli * Up to this point the pmd is present and huge and 180271e3aac0SAndrea Arcangeli * userland has the whole access to the hugepage 180371e3aac0SAndrea Arcangeli * during the split (which happens in place). If we 180471e3aac0SAndrea Arcangeli * overwrite the pmd with the not-huge version 180571e3aac0SAndrea Arcangeli * pointing to the pte here (which of course we could 180671e3aac0SAndrea Arcangeli * if all CPUs were bug free), userland could trigger 180771e3aac0SAndrea Arcangeli * a small page size TLB miss on the small sized TLB 180871e3aac0SAndrea Arcangeli * while the hugepage TLB entry is still established 180971e3aac0SAndrea Arcangeli * in the huge TLB. Some CPU doesn't like that. See 181071e3aac0SAndrea Arcangeli * http://support.amd.com/us/Processor_TechDocs/41322.pdf, 181171e3aac0SAndrea Arcangeli * Erratum 383 on page 93. Intel should be safe but is 181271e3aac0SAndrea Arcangeli * also warns that it's only safe if the permission 181371e3aac0SAndrea Arcangeli * and cache attributes of the two entries loaded in 181471e3aac0SAndrea Arcangeli * the two TLB is identical (which should be the case 181571e3aac0SAndrea Arcangeli * here). But it is generally safer to never allow 181671e3aac0SAndrea Arcangeli * small and huge TLB entries for the same virtual 181771e3aac0SAndrea Arcangeli * address to be loaded simultaneously. So instead of 181871e3aac0SAndrea Arcangeli * doing "pmd_populate(); flush_tlb_range();" we first 181971e3aac0SAndrea Arcangeli * mark the current pmd notpresent (atomically because 182071e3aac0SAndrea Arcangeli * here the pmd_trans_huge and pmd_trans_splitting 182171e3aac0SAndrea Arcangeli * must remain set at all times on the pmd until the 182271e3aac0SAndrea Arcangeli * split is complete for this pmd), then we flush the 182371e3aac0SAndrea Arcangeli * SMP TLB and finally we write the non-huge version 182471e3aac0SAndrea Arcangeli * of the pmd entry with pmd_populate. 182571e3aac0SAndrea Arcangeli */ 182646dcde73SGerald Schaefer pmdp_invalidate(vma, address, pmd); 182771e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 182871e3aac0SAndrea Arcangeli ret = 1; 1829117b0791SKirill A. Shutemov spin_unlock(ptl); 183071e3aac0SAndrea Arcangeli } 183171e3aac0SAndrea Arcangeli 183271e3aac0SAndrea Arcangeli return ret; 183371e3aac0SAndrea Arcangeli } 183471e3aac0SAndrea Arcangeli 18355a505085SIngo Molnar /* must be called with anon_vma->root->rwsem held */ 183671e3aac0SAndrea Arcangeli static void __split_huge_page(struct page *page, 18375bc7b8acSShaohua Li struct anon_vma *anon_vma, 18385bc7b8acSShaohua Li struct list_head *list) 183971e3aac0SAndrea Arcangeli { 184071e3aac0SAndrea Arcangeli int mapcount, mapcount2; 1841bf181b9fSMichel Lespinasse pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); 184271e3aac0SAndrea Arcangeli struct anon_vma_chain *avc; 184371e3aac0SAndrea Arcangeli 184471e3aac0SAndrea Arcangeli BUG_ON(!PageHead(page)); 184571e3aac0SAndrea Arcangeli BUG_ON(PageTail(page)); 184671e3aac0SAndrea Arcangeli 184771e3aac0SAndrea Arcangeli mapcount = 0; 1848bf181b9fSMichel Lespinasse anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { 184971e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 185071e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 185171e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 185271e3aac0SAndrea Arcangeli mapcount += __split_huge_page_splitting(page, vma, addr); 185371e3aac0SAndrea Arcangeli } 185405759d38SAndrea Arcangeli /* 185505759d38SAndrea Arcangeli * It is critical that new vmas are added to the tail of the 185605759d38SAndrea Arcangeli * anon_vma list. This guarantes that if copy_huge_pmd() runs 185705759d38SAndrea Arcangeli * and establishes a child pmd before 185805759d38SAndrea Arcangeli * __split_huge_page_splitting() freezes the parent pmd (so if 185905759d38SAndrea Arcangeli * we fail to prevent copy_huge_pmd() from running until the 186005759d38SAndrea Arcangeli * whole __split_huge_page() is complete), we will still see 186105759d38SAndrea Arcangeli * the newly established pmd of the child later during the 186205759d38SAndrea Arcangeli * walk, to be able to set it as pmd_trans_splitting too. 186305759d38SAndrea Arcangeli */ 1864ff9e43ebSKirill A. Shutemov if (mapcount != page_mapcount(page)) { 1865ae3a8c1cSAndrew Morton pr_err("mapcount %d page_mapcount %d\n", 186605759d38SAndrea Arcangeli mapcount, page_mapcount(page)); 1867ff9e43ebSKirill A. Shutemov BUG(); 1868ff9e43ebSKirill A. Shutemov } 186971e3aac0SAndrea Arcangeli 18705bc7b8acSShaohua Li __split_huge_page_refcount(page, list); 187171e3aac0SAndrea Arcangeli 187271e3aac0SAndrea Arcangeli mapcount2 = 0; 1873bf181b9fSMichel Lespinasse anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { 187471e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 187571e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 187671e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 187771e3aac0SAndrea Arcangeli mapcount2 += __split_huge_page_map(page, vma, addr); 187871e3aac0SAndrea Arcangeli } 1879ff9e43ebSKirill A. Shutemov if (mapcount != mapcount2) { 1880ae3a8c1cSAndrew Morton pr_err("mapcount %d mapcount2 %d page_mapcount %d\n", 188105759d38SAndrea Arcangeli mapcount, mapcount2, page_mapcount(page)); 1882ff9e43ebSKirill A. Shutemov BUG(); 1883ff9e43ebSKirill A. Shutemov } 188471e3aac0SAndrea Arcangeli } 188571e3aac0SAndrea Arcangeli 18865bc7b8acSShaohua Li /* 18875bc7b8acSShaohua Li * Split a hugepage into normal pages. This doesn't change the position of head 18885bc7b8acSShaohua Li * page. If @list is null, tail pages will be added to LRU list, otherwise, to 18895bc7b8acSShaohua Li * @list. Both head page and tail pages will inherit mapping, flags, and so on 18905bc7b8acSShaohua Li * from the hugepage. 18915bc7b8acSShaohua Li * Return 0 if the hugepage is split successfully otherwise return 1. 18925bc7b8acSShaohua Li */ 18935bc7b8acSShaohua Li int split_huge_page_to_list(struct page *page, struct list_head *list) 189471e3aac0SAndrea Arcangeli { 189571e3aac0SAndrea Arcangeli struct anon_vma *anon_vma; 189671e3aac0SAndrea Arcangeli int ret = 1; 189771e3aac0SAndrea Arcangeli 18985918d10aSKirill A. Shutemov BUG_ON(is_huge_zero_page(page)); 189971e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page)); 1900062f1af2SMel Gorman 1901062f1af2SMel Gorman /* 1902062f1af2SMel Gorman * The caller does not necessarily hold an mmap_sem that would prevent 1903062f1af2SMel Gorman * the anon_vma disappearing so we first we take a reference to it 1904062f1af2SMel Gorman * and then lock the anon_vma for write. This is similar to 1905062f1af2SMel Gorman * page_lock_anon_vma_read except the write lock is taken to serialise 1906062f1af2SMel Gorman * against parallel split or collapse operations. 1907062f1af2SMel Gorman */ 1908062f1af2SMel Gorman anon_vma = page_get_anon_vma(page); 190971e3aac0SAndrea Arcangeli if (!anon_vma) 191071e3aac0SAndrea Arcangeli goto out; 1911062f1af2SMel Gorman anon_vma_lock_write(anon_vma); 1912062f1af2SMel Gorman 191371e3aac0SAndrea Arcangeli ret = 0; 191471e3aac0SAndrea Arcangeli if (!PageCompound(page)) 191571e3aac0SAndrea Arcangeli goto out_unlock; 191671e3aac0SAndrea Arcangeli 191771e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page)); 19185bc7b8acSShaohua Li __split_huge_page(page, anon_vma, list); 191981ab4201SAndi Kleen count_vm_event(THP_SPLIT); 192071e3aac0SAndrea Arcangeli 192171e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page)); 192271e3aac0SAndrea Arcangeli out_unlock: 192308b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 1924062f1af2SMel Gorman put_anon_vma(anon_vma); 192571e3aac0SAndrea Arcangeli out: 192671e3aac0SAndrea Arcangeli return ret; 192771e3aac0SAndrea Arcangeli } 192871e3aac0SAndrea Arcangeli 19299050d7ebSVlastimil Babka #define VM_NO_THP (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE) 193078f11a25SAndrea Arcangeli 193160ab3244SAndrea Arcangeli int hugepage_madvise(struct vm_area_struct *vma, 193260ab3244SAndrea Arcangeli unsigned long *vm_flags, int advice) 19330af4e98bSAndrea Arcangeli { 1934a664b2d8SAndrea Arcangeli switch (advice) { 1935a664b2d8SAndrea Arcangeli case MADV_HUGEPAGE: 19361e1836e8SAlex Thorlton #ifdef CONFIG_S390 19371e1836e8SAlex Thorlton /* 19381e1836e8SAlex Thorlton * qemu blindly sets MADV_HUGEPAGE on all allocations, but s390 19391e1836e8SAlex Thorlton * can't handle this properly after s390_enable_sie, so we simply 19401e1836e8SAlex Thorlton * ignore the madvise to prevent qemu from causing a SIGSEGV. 19411e1836e8SAlex Thorlton */ 19421e1836e8SAlex Thorlton if (mm_has_pgste(vma->vm_mm)) 19431e1836e8SAlex Thorlton return 0; 19441e1836e8SAlex Thorlton #endif 19450af4e98bSAndrea Arcangeli /* 19460af4e98bSAndrea Arcangeli * Be somewhat over-protective like KSM for now! 19470af4e98bSAndrea Arcangeli */ 194878f11a25SAndrea Arcangeli if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) 19490af4e98bSAndrea Arcangeli return -EINVAL; 1950a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_NOHUGEPAGE; 19510af4e98bSAndrea Arcangeli *vm_flags |= VM_HUGEPAGE; 195260ab3244SAndrea Arcangeli /* 195360ab3244SAndrea Arcangeli * If the vma become good for khugepaged to scan, 195460ab3244SAndrea Arcangeli * register it here without waiting a page fault that 195560ab3244SAndrea Arcangeli * may not happen any time soon. 195660ab3244SAndrea Arcangeli */ 195760ab3244SAndrea Arcangeli if (unlikely(khugepaged_enter_vma_merge(vma))) 195860ab3244SAndrea Arcangeli return -ENOMEM; 1959a664b2d8SAndrea Arcangeli break; 1960a664b2d8SAndrea Arcangeli case MADV_NOHUGEPAGE: 1961a664b2d8SAndrea Arcangeli /* 1962a664b2d8SAndrea Arcangeli * Be somewhat over-protective like KSM for now! 1963a664b2d8SAndrea Arcangeli */ 196478f11a25SAndrea Arcangeli if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) 1965a664b2d8SAndrea Arcangeli return -EINVAL; 1966a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_HUGEPAGE; 1967a664b2d8SAndrea Arcangeli *vm_flags |= VM_NOHUGEPAGE; 196860ab3244SAndrea Arcangeli /* 196960ab3244SAndrea Arcangeli * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning 197060ab3244SAndrea Arcangeli * this vma even if we leave the mm registered in khugepaged if 197160ab3244SAndrea Arcangeli * it got registered before VM_NOHUGEPAGE was set. 197260ab3244SAndrea Arcangeli */ 1973a664b2d8SAndrea Arcangeli break; 1974a664b2d8SAndrea Arcangeli } 19750af4e98bSAndrea Arcangeli 19760af4e98bSAndrea Arcangeli return 0; 19770af4e98bSAndrea Arcangeli } 19780af4e98bSAndrea Arcangeli 1979ba76149fSAndrea Arcangeli static int __init khugepaged_slab_init(void) 1980ba76149fSAndrea Arcangeli { 1981ba76149fSAndrea Arcangeli mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", 1982ba76149fSAndrea Arcangeli sizeof(struct mm_slot), 1983ba76149fSAndrea Arcangeli __alignof__(struct mm_slot), 0, NULL); 1984ba76149fSAndrea Arcangeli if (!mm_slot_cache) 1985ba76149fSAndrea Arcangeli return -ENOMEM; 1986ba76149fSAndrea Arcangeli 1987ba76149fSAndrea Arcangeli return 0; 1988ba76149fSAndrea Arcangeli } 1989ba76149fSAndrea Arcangeli 1990ba76149fSAndrea Arcangeli static inline struct mm_slot *alloc_mm_slot(void) 1991ba76149fSAndrea Arcangeli { 1992ba76149fSAndrea Arcangeli if (!mm_slot_cache) /* initialization failed */ 1993ba76149fSAndrea Arcangeli return NULL; 1994ba76149fSAndrea Arcangeli return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); 1995ba76149fSAndrea Arcangeli } 1996ba76149fSAndrea Arcangeli 1997ba76149fSAndrea Arcangeli static inline void free_mm_slot(struct mm_slot *mm_slot) 1998ba76149fSAndrea Arcangeli { 1999ba76149fSAndrea Arcangeli kmem_cache_free(mm_slot_cache, mm_slot); 2000ba76149fSAndrea Arcangeli } 2001ba76149fSAndrea Arcangeli 2002ba76149fSAndrea Arcangeli static struct mm_slot *get_mm_slot(struct mm_struct *mm) 2003ba76149fSAndrea Arcangeli { 2004ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2005ba76149fSAndrea Arcangeli 2006b67bfe0dSSasha Levin hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm) 2007ba76149fSAndrea Arcangeli if (mm == mm_slot->mm) 2008ba76149fSAndrea Arcangeli return mm_slot; 200943b5fbbdSSasha Levin 2010ba76149fSAndrea Arcangeli return NULL; 2011ba76149fSAndrea Arcangeli } 2012ba76149fSAndrea Arcangeli 2013ba76149fSAndrea Arcangeli static void insert_to_mm_slots_hash(struct mm_struct *mm, 2014ba76149fSAndrea Arcangeli struct mm_slot *mm_slot) 2015ba76149fSAndrea Arcangeli { 2016ba76149fSAndrea Arcangeli mm_slot->mm = mm; 201743b5fbbdSSasha Levin hash_add(mm_slots_hash, &mm_slot->hash, (long)mm); 2018ba76149fSAndrea Arcangeli } 2019ba76149fSAndrea Arcangeli 2020ba76149fSAndrea Arcangeli static inline int khugepaged_test_exit(struct mm_struct *mm) 2021ba76149fSAndrea Arcangeli { 2022ba76149fSAndrea Arcangeli return atomic_read(&mm->mm_users) == 0; 2023ba76149fSAndrea Arcangeli } 2024ba76149fSAndrea Arcangeli 2025ba76149fSAndrea Arcangeli int __khugepaged_enter(struct mm_struct *mm) 2026ba76149fSAndrea Arcangeli { 2027ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2028ba76149fSAndrea Arcangeli int wakeup; 2029ba76149fSAndrea Arcangeli 2030ba76149fSAndrea Arcangeli mm_slot = alloc_mm_slot(); 2031ba76149fSAndrea Arcangeli if (!mm_slot) 2032ba76149fSAndrea Arcangeli return -ENOMEM; 2033ba76149fSAndrea Arcangeli 2034ba76149fSAndrea Arcangeli /* __khugepaged_exit() must not run from under us */ 2035ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_test_exit(mm)); 2036ba76149fSAndrea Arcangeli if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { 2037ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2038ba76149fSAndrea Arcangeli return 0; 2039ba76149fSAndrea Arcangeli } 2040ba76149fSAndrea Arcangeli 2041ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2042ba76149fSAndrea Arcangeli insert_to_mm_slots_hash(mm, mm_slot); 2043ba76149fSAndrea Arcangeli /* 2044ba76149fSAndrea Arcangeli * Insert just behind the scanning cursor, to let the area settle 2045ba76149fSAndrea Arcangeli * down a little. 2046ba76149fSAndrea Arcangeli */ 2047ba76149fSAndrea Arcangeli wakeup = list_empty(&khugepaged_scan.mm_head); 2048ba76149fSAndrea Arcangeli list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); 2049ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2050ba76149fSAndrea Arcangeli 2051ba76149fSAndrea Arcangeli atomic_inc(&mm->mm_count); 2052ba76149fSAndrea Arcangeli if (wakeup) 2053ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 2054ba76149fSAndrea Arcangeli 2055ba76149fSAndrea Arcangeli return 0; 2056ba76149fSAndrea Arcangeli } 2057ba76149fSAndrea Arcangeli 2058ba76149fSAndrea Arcangeli int khugepaged_enter_vma_merge(struct vm_area_struct *vma) 2059ba76149fSAndrea Arcangeli { 2060ba76149fSAndrea Arcangeli unsigned long hstart, hend; 2061ba76149fSAndrea Arcangeli if (!vma->anon_vma) 2062ba76149fSAndrea Arcangeli /* 2063ba76149fSAndrea Arcangeli * Not yet faulted in so we will register later in the 2064ba76149fSAndrea Arcangeli * page fault if needed. 2065ba76149fSAndrea Arcangeli */ 2066ba76149fSAndrea Arcangeli return 0; 206778f11a25SAndrea Arcangeli if (vma->vm_ops) 2068ba76149fSAndrea Arcangeli /* khugepaged not yet working on file or special mappings */ 2069ba76149fSAndrea Arcangeli return 0; 2070b3b9c293SKonstantin Khlebnikov VM_BUG_ON(vma->vm_flags & VM_NO_THP); 2071ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2072ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2073ba76149fSAndrea Arcangeli if (hstart < hend) 2074ba76149fSAndrea Arcangeli return khugepaged_enter(vma); 2075ba76149fSAndrea Arcangeli return 0; 2076ba76149fSAndrea Arcangeli } 2077ba76149fSAndrea Arcangeli 2078ba76149fSAndrea Arcangeli void __khugepaged_exit(struct mm_struct *mm) 2079ba76149fSAndrea Arcangeli { 2080ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2081ba76149fSAndrea Arcangeli int free = 0; 2082ba76149fSAndrea Arcangeli 2083ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2084ba76149fSAndrea Arcangeli mm_slot = get_mm_slot(mm); 2085ba76149fSAndrea Arcangeli if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { 208643b5fbbdSSasha Levin hash_del(&mm_slot->hash); 2087ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 2088ba76149fSAndrea Arcangeli free = 1; 2089ba76149fSAndrea Arcangeli } 2090d788e80aSChris Wright spin_unlock(&khugepaged_mm_lock); 2091ba76149fSAndrea Arcangeli 2092ba76149fSAndrea Arcangeli if (free) { 2093ba76149fSAndrea Arcangeli clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 2094ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2095ba76149fSAndrea Arcangeli mmdrop(mm); 2096ba76149fSAndrea Arcangeli } else if (mm_slot) { 2097ba76149fSAndrea Arcangeli /* 2098ba76149fSAndrea Arcangeli * This is required to serialize against 2099ba76149fSAndrea Arcangeli * khugepaged_test_exit() (which is guaranteed to run 2100ba76149fSAndrea Arcangeli * under mmap sem read mode). Stop here (after we 2101ba76149fSAndrea Arcangeli * return all pagetables will be destroyed) until 2102ba76149fSAndrea Arcangeli * khugepaged has finished working on the pagetables 2103ba76149fSAndrea Arcangeli * under the mmap_sem. 2104ba76149fSAndrea Arcangeli */ 2105ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 2106ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 2107d788e80aSChris Wright } 2108ba76149fSAndrea Arcangeli } 2109ba76149fSAndrea Arcangeli 2110ba76149fSAndrea Arcangeli static void release_pte_page(struct page *page) 2111ba76149fSAndrea Arcangeli { 2112ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 2113ba76149fSAndrea Arcangeli dec_zone_page_state(page, NR_ISOLATED_ANON + 0); 2114ba76149fSAndrea Arcangeli unlock_page(page); 2115ba76149fSAndrea Arcangeli putback_lru_page(page); 2116ba76149fSAndrea Arcangeli } 2117ba76149fSAndrea Arcangeli 2118ba76149fSAndrea Arcangeli static void release_pte_pages(pte_t *pte, pte_t *_pte) 2119ba76149fSAndrea Arcangeli { 2120ba76149fSAndrea Arcangeli while (--_pte >= pte) { 2121ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2122ba76149fSAndrea Arcangeli if (!pte_none(pteval)) 2123ba76149fSAndrea Arcangeli release_pte_page(pte_page(pteval)); 2124ba76149fSAndrea Arcangeli } 2125ba76149fSAndrea Arcangeli } 2126ba76149fSAndrea Arcangeli 2127ba76149fSAndrea Arcangeli static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 2128ba76149fSAndrea Arcangeli unsigned long address, 2129ba76149fSAndrea Arcangeli pte_t *pte) 2130ba76149fSAndrea Arcangeli { 2131ba76149fSAndrea Arcangeli struct page *page; 2132ba76149fSAndrea Arcangeli pte_t *_pte; 2133344aa35cSBob Liu int referenced = 0, none = 0; 2134ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; 2135ba76149fSAndrea Arcangeli _pte++, address += PAGE_SIZE) { 2136ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2137ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 2138ba76149fSAndrea Arcangeli if (++none <= khugepaged_max_ptes_none) 2139ba76149fSAndrea Arcangeli continue; 2140344aa35cSBob Liu else 2141ba76149fSAndrea Arcangeli goto out; 2142ba76149fSAndrea Arcangeli } 2143344aa35cSBob Liu if (!pte_present(pteval) || !pte_write(pteval)) 2144ba76149fSAndrea Arcangeli goto out; 2145ba76149fSAndrea Arcangeli page = vm_normal_page(vma, address, pteval); 2146344aa35cSBob Liu if (unlikely(!page)) 2147ba76149fSAndrea Arcangeli goto out; 2148344aa35cSBob Liu 2149309381feSSasha Levin VM_BUG_ON_PAGE(PageCompound(page), page); 2150309381feSSasha Levin VM_BUG_ON_PAGE(!PageAnon(page), page); 2151309381feSSasha Levin VM_BUG_ON_PAGE(!PageSwapBacked(page), page); 2152ba76149fSAndrea Arcangeli 2153ba76149fSAndrea Arcangeli /* cannot use mapcount: can't collapse if there's a gup pin */ 2154344aa35cSBob Liu if (page_count(page) != 1) 2155ba76149fSAndrea Arcangeli goto out; 2156ba76149fSAndrea Arcangeli /* 2157ba76149fSAndrea Arcangeli * We can do it before isolate_lru_page because the 2158ba76149fSAndrea Arcangeli * page can't be freed from under us. NOTE: PG_lock 2159ba76149fSAndrea Arcangeli * is needed to serialize against split_huge_page 2160ba76149fSAndrea Arcangeli * when invoked from the VM. 2161ba76149fSAndrea Arcangeli */ 2162344aa35cSBob Liu if (!trylock_page(page)) 2163ba76149fSAndrea Arcangeli goto out; 2164ba76149fSAndrea Arcangeli /* 2165ba76149fSAndrea Arcangeli * Isolate the page to avoid collapsing an hugepage 2166ba76149fSAndrea Arcangeli * currently in use by the VM. 2167ba76149fSAndrea Arcangeli */ 2168ba76149fSAndrea Arcangeli if (isolate_lru_page(page)) { 2169ba76149fSAndrea Arcangeli unlock_page(page); 2170ba76149fSAndrea Arcangeli goto out; 2171ba76149fSAndrea Arcangeli } 2172ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 2173ba76149fSAndrea Arcangeli inc_zone_page_state(page, NR_ISOLATED_ANON + 0); 2174309381feSSasha Levin VM_BUG_ON_PAGE(!PageLocked(page), page); 2175309381feSSasha Levin VM_BUG_ON_PAGE(PageLRU(page), page); 2176ba76149fSAndrea Arcangeli 2177ba76149fSAndrea Arcangeli /* If there is no mapped pte young don't collapse the page */ 21788ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 21798ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 2180ba76149fSAndrea Arcangeli referenced = 1; 2181ba76149fSAndrea Arcangeli } 2182344aa35cSBob Liu if (likely(referenced)) 2183344aa35cSBob Liu return 1; 2184ba76149fSAndrea Arcangeli out: 2185344aa35cSBob Liu release_pte_pages(pte, _pte); 2186344aa35cSBob Liu return 0; 2187ba76149fSAndrea Arcangeli } 2188ba76149fSAndrea Arcangeli 2189ba76149fSAndrea Arcangeli static void __collapse_huge_page_copy(pte_t *pte, struct page *page, 2190ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 2191ba76149fSAndrea Arcangeli unsigned long address, 2192ba76149fSAndrea Arcangeli spinlock_t *ptl) 2193ba76149fSAndrea Arcangeli { 2194ba76149fSAndrea Arcangeli pte_t *_pte; 2195ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { 2196ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2197ba76149fSAndrea Arcangeli struct page *src_page; 2198ba76149fSAndrea Arcangeli 2199ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 2200ba76149fSAndrea Arcangeli clear_user_highpage(page, address); 2201ba76149fSAndrea Arcangeli add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); 2202ba76149fSAndrea Arcangeli } else { 2203ba76149fSAndrea Arcangeli src_page = pte_page(pteval); 2204ba76149fSAndrea Arcangeli copy_user_highpage(page, src_page, address, vma); 2205309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page); 2206ba76149fSAndrea Arcangeli release_pte_page(src_page); 2207ba76149fSAndrea Arcangeli /* 2208ba76149fSAndrea Arcangeli * ptl mostly unnecessary, but preempt has to 2209ba76149fSAndrea Arcangeli * be disabled to update the per-cpu stats 2210ba76149fSAndrea Arcangeli * inside page_remove_rmap(). 2211ba76149fSAndrea Arcangeli */ 2212ba76149fSAndrea Arcangeli spin_lock(ptl); 2213ba76149fSAndrea Arcangeli /* 2214ba76149fSAndrea Arcangeli * paravirt calls inside pte_clear here are 2215ba76149fSAndrea Arcangeli * superfluous. 2216ba76149fSAndrea Arcangeli */ 2217ba76149fSAndrea Arcangeli pte_clear(vma->vm_mm, address, _pte); 2218ba76149fSAndrea Arcangeli page_remove_rmap(src_page); 2219ba76149fSAndrea Arcangeli spin_unlock(ptl); 2220ba76149fSAndrea Arcangeli free_page_and_swap_cache(src_page); 2221ba76149fSAndrea Arcangeli } 2222ba76149fSAndrea Arcangeli 2223ba76149fSAndrea Arcangeli address += PAGE_SIZE; 2224ba76149fSAndrea Arcangeli page++; 2225ba76149fSAndrea Arcangeli } 2226ba76149fSAndrea Arcangeli } 2227ba76149fSAndrea Arcangeli 222826234f36SXiao Guangrong static void khugepaged_alloc_sleep(void) 222926234f36SXiao Guangrong { 223026234f36SXiao Guangrong wait_event_freezable_timeout(khugepaged_wait, false, 223126234f36SXiao Guangrong msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); 223226234f36SXiao Guangrong } 223326234f36SXiao Guangrong 22349f1b868aSBob Liu static int khugepaged_node_load[MAX_NUMNODES]; 22359f1b868aSBob Liu 223626234f36SXiao Guangrong #ifdef CONFIG_NUMA 22379f1b868aSBob Liu static int khugepaged_find_target_node(void) 22389f1b868aSBob Liu { 22399f1b868aSBob Liu static int last_khugepaged_target_node = NUMA_NO_NODE; 22409f1b868aSBob Liu int nid, target_node = 0, max_value = 0; 22419f1b868aSBob Liu 22429f1b868aSBob Liu /* find first node with max normal pages hit */ 22439f1b868aSBob Liu for (nid = 0; nid < MAX_NUMNODES; nid++) 22449f1b868aSBob Liu if (khugepaged_node_load[nid] > max_value) { 22459f1b868aSBob Liu max_value = khugepaged_node_load[nid]; 22469f1b868aSBob Liu target_node = nid; 22479f1b868aSBob Liu } 22489f1b868aSBob Liu 22499f1b868aSBob Liu /* do some balance if several nodes have the same hit record */ 22509f1b868aSBob Liu if (target_node <= last_khugepaged_target_node) 22519f1b868aSBob Liu for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES; 22529f1b868aSBob Liu nid++) 22539f1b868aSBob Liu if (max_value == khugepaged_node_load[nid]) { 22549f1b868aSBob Liu target_node = nid; 22559f1b868aSBob Liu break; 22569f1b868aSBob Liu } 22579f1b868aSBob Liu 22589f1b868aSBob Liu last_khugepaged_target_node = target_node; 22599f1b868aSBob Liu return target_node; 22609f1b868aSBob Liu } 22619f1b868aSBob Liu 226226234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 226326234f36SXiao Guangrong { 226426234f36SXiao Guangrong if (IS_ERR(*hpage)) { 226526234f36SXiao Guangrong if (!*wait) 226626234f36SXiao Guangrong return false; 226726234f36SXiao Guangrong 226826234f36SXiao Guangrong *wait = false; 2269e3b4126cSXiao Guangrong *hpage = NULL; 227026234f36SXiao Guangrong khugepaged_alloc_sleep(); 227126234f36SXiao Guangrong } else if (*hpage) { 227226234f36SXiao Guangrong put_page(*hpage); 227326234f36SXiao Guangrong *hpage = NULL; 227426234f36SXiao Guangrong } 227526234f36SXiao Guangrong 227626234f36SXiao Guangrong return true; 227726234f36SXiao Guangrong } 227826234f36SXiao Guangrong 227926234f36SXiao Guangrong static struct page 228026234f36SXiao Guangrong *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, 228126234f36SXiao Guangrong struct vm_area_struct *vma, unsigned long address, 228226234f36SXiao Guangrong int node) 228326234f36SXiao Guangrong { 2284309381feSSasha Levin VM_BUG_ON_PAGE(*hpage, *hpage); 228526234f36SXiao Guangrong /* 228626234f36SXiao Guangrong * Allocate the page while the vma is still valid and under 228726234f36SXiao Guangrong * the mmap_sem read mode so there is no memory allocation 228826234f36SXiao Guangrong * later when we take the mmap_sem in write mode. This is more 228926234f36SXiao Guangrong * friendly behavior (OTOH it may actually hide bugs) to 229026234f36SXiao Guangrong * filesystems in userland with daemons allocating memory in 229126234f36SXiao Guangrong * the userland I/O paths. Allocating memory with the 229226234f36SXiao Guangrong * mmap_sem in read mode is good idea also to allow greater 229326234f36SXiao Guangrong * scalability. 229426234f36SXiao Guangrong */ 22959f1b868aSBob Liu *hpage = alloc_pages_exact_node(node, alloc_hugepage_gfpmask( 22969f1b868aSBob Liu khugepaged_defrag(), __GFP_OTHER_NODE), HPAGE_PMD_ORDER); 229726234f36SXiao Guangrong /* 229826234f36SXiao Guangrong * After allocating the hugepage, release the mmap_sem read lock in 229926234f36SXiao Guangrong * preparation for taking it in write mode. 230026234f36SXiao Guangrong */ 230126234f36SXiao Guangrong up_read(&mm->mmap_sem); 230226234f36SXiao Guangrong if (unlikely(!*hpage)) { 230326234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 230426234f36SXiao Guangrong *hpage = ERR_PTR(-ENOMEM); 230526234f36SXiao Guangrong return NULL; 230626234f36SXiao Guangrong } 230726234f36SXiao Guangrong 230826234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 230926234f36SXiao Guangrong return *hpage; 231026234f36SXiao Guangrong } 231126234f36SXiao Guangrong #else 23129f1b868aSBob Liu static int khugepaged_find_target_node(void) 23139f1b868aSBob Liu { 23149f1b868aSBob Liu return 0; 23159f1b868aSBob Liu } 23169f1b868aSBob Liu 231710dc4155SBob Liu static inline struct page *alloc_hugepage(int defrag) 231810dc4155SBob Liu { 231910dc4155SBob Liu return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), 232010dc4155SBob Liu HPAGE_PMD_ORDER); 232110dc4155SBob Liu } 232210dc4155SBob Liu 232326234f36SXiao Guangrong static struct page *khugepaged_alloc_hugepage(bool *wait) 232426234f36SXiao Guangrong { 232526234f36SXiao Guangrong struct page *hpage; 232626234f36SXiao Guangrong 232726234f36SXiao Guangrong do { 232826234f36SXiao Guangrong hpage = alloc_hugepage(khugepaged_defrag()); 232926234f36SXiao Guangrong if (!hpage) { 233026234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 233126234f36SXiao Guangrong if (!*wait) 233226234f36SXiao Guangrong return NULL; 233326234f36SXiao Guangrong 233426234f36SXiao Guangrong *wait = false; 233526234f36SXiao Guangrong khugepaged_alloc_sleep(); 233626234f36SXiao Guangrong } else 233726234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 233826234f36SXiao Guangrong } while (unlikely(!hpage) && likely(khugepaged_enabled())); 233926234f36SXiao Guangrong 234026234f36SXiao Guangrong return hpage; 234126234f36SXiao Guangrong } 234226234f36SXiao Guangrong 234326234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 234426234f36SXiao Guangrong { 234526234f36SXiao Guangrong if (!*hpage) 234626234f36SXiao Guangrong *hpage = khugepaged_alloc_hugepage(wait); 234726234f36SXiao Guangrong 234826234f36SXiao Guangrong if (unlikely(!*hpage)) 234926234f36SXiao Guangrong return false; 235026234f36SXiao Guangrong 235126234f36SXiao Guangrong return true; 235226234f36SXiao Guangrong } 235326234f36SXiao Guangrong 235426234f36SXiao Guangrong static struct page 235526234f36SXiao Guangrong *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, 235626234f36SXiao Guangrong struct vm_area_struct *vma, unsigned long address, 235726234f36SXiao Guangrong int node) 235826234f36SXiao Guangrong { 235926234f36SXiao Guangrong up_read(&mm->mmap_sem); 236026234f36SXiao Guangrong VM_BUG_ON(!*hpage); 236126234f36SXiao Guangrong return *hpage; 236226234f36SXiao Guangrong } 236326234f36SXiao Guangrong #endif 236426234f36SXiao Guangrong 2365fa475e51SBob Liu static bool hugepage_vma_check(struct vm_area_struct *vma) 2366fa475e51SBob Liu { 2367fa475e51SBob Liu if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || 2368fa475e51SBob Liu (vma->vm_flags & VM_NOHUGEPAGE)) 2369fa475e51SBob Liu return false; 2370fa475e51SBob Liu 2371fa475e51SBob Liu if (!vma->anon_vma || vma->vm_ops) 2372fa475e51SBob Liu return false; 2373fa475e51SBob Liu if (is_vma_temporary_stack(vma)) 2374fa475e51SBob Liu return false; 2375fa475e51SBob Liu VM_BUG_ON(vma->vm_flags & VM_NO_THP); 2376fa475e51SBob Liu return true; 2377fa475e51SBob Liu } 2378fa475e51SBob Liu 2379ba76149fSAndrea Arcangeli static void collapse_huge_page(struct mm_struct *mm, 2380ba76149fSAndrea Arcangeli unsigned long address, 2381ce83d217SAndrea Arcangeli struct page **hpage, 23825c4b4be3SAndi Kleen struct vm_area_struct *vma, 23835c4b4be3SAndi Kleen int node) 2384ba76149fSAndrea Arcangeli { 2385ba76149fSAndrea Arcangeli pmd_t *pmd, _pmd; 2386ba76149fSAndrea Arcangeli pte_t *pte; 2387ba76149fSAndrea Arcangeli pgtable_t pgtable; 2388ba76149fSAndrea Arcangeli struct page *new_page; 2389c4088ebdSKirill A. Shutemov spinlock_t *pmd_ptl, *pte_ptl; 2390ba76149fSAndrea Arcangeli int isolated; 2391ba76149fSAndrea Arcangeli unsigned long hstart, hend; 23922ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 23932ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 2394ba76149fSAndrea Arcangeli 2395ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 2396692e0b35SAndrea Arcangeli 239726234f36SXiao Guangrong /* release the mmap_sem read lock. */ 239826234f36SXiao Guangrong new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); 239926234f36SXiao Guangrong if (!new_page) 2400ce83d217SAndrea Arcangeli return; 2401ce83d217SAndrea Arcangeli 2402d715ae08SMichal Hocko if (unlikely(mem_cgroup_charge_anon(new_page, mm, GFP_KERNEL))) 2403692e0b35SAndrea Arcangeli return; 2404ba76149fSAndrea Arcangeli 2405ba76149fSAndrea Arcangeli /* 2406ba76149fSAndrea Arcangeli * Prevent all access to pagetables with the exception of 2407ba76149fSAndrea Arcangeli * gup_fast later hanlded by the ptep_clear_flush and the VM 2408ba76149fSAndrea Arcangeli * handled by the anon_vma lock + PG_lock. 2409ba76149fSAndrea Arcangeli */ 2410ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 2411ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2412ba76149fSAndrea Arcangeli goto out; 2413ba76149fSAndrea Arcangeli 2414ba76149fSAndrea Arcangeli vma = find_vma(mm, address); 2415a8f531ebSLibin if (!vma) 2416a8f531ebSLibin goto out; 2417ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2418ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2419ba76149fSAndrea Arcangeli if (address < hstart || address + HPAGE_PMD_SIZE > hend) 2420ba76149fSAndrea Arcangeli goto out; 2421fa475e51SBob Liu if (!hugepage_vma_check(vma)) 2422ba76149fSAndrea Arcangeli goto out; 24236219049aSBob Liu pmd = mm_find_pmd(mm, address); 24246219049aSBob Liu if (!pmd) 2425ba76149fSAndrea Arcangeli goto out; 2426ba76149fSAndrea Arcangeli 24274fc3f1d6SIngo Molnar anon_vma_lock_write(vma->anon_vma); 2428ba76149fSAndrea Arcangeli 2429ba76149fSAndrea Arcangeli pte = pte_offset_map(pmd, address); 2430c4088ebdSKirill A. Shutemov pte_ptl = pte_lockptr(mm, pmd); 2431ba76149fSAndrea Arcangeli 24322ec74c3eSSagi Grimberg mmun_start = address; 24332ec74c3eSSagi Grimberg mmun_end = address + HPAGE_PMD_SIZE; 24342ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2435c4088ebdSKirill A. Shutemov pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */ 2436ba76149fSAndrea Arcangeli /* 2437ba76149fSAndrea Arcangeli * After this gup_fast can't run anymore. This also removes 2438ba76149fSAndrea Arcangeli * any huge TLB entry from the CPU so we won't allow 2439ba76149fSAndrea Arcangeli * huge and small TLB entries for the same virtual address 2440ba76149fSAndrea Arcangeli * to avoid the risk of CPU bugs in that area. 2441ba76149fSAndrea Arcangeli */ 24422ec74c3eSSagi Grimberg _pmd = pmdp_clear_flush(vma, address, pmd); 2443c4088ebdSKirill A. Shutemov spin_unlock(pmd_ptl); 24442ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2445ba76149fSAndrea Arcangeli 2446c4088ebdSKirill A. Shutemov spin_lock(pte_ptl); 2447ba76149fSAndrea Arcangeli isolated = __collapse_huge_page_isolate(vma, address, pte); 2448c4088ebdSKirill A. Shutemov spin_unlock(pte_ptl); 2449ba76149fSAndrea Arcangeli 2450ba76149fSAndrea Arcangeli if (unlikely(!isolated)) { 2451453c7192SJohannes Weiner pte_unmap(pte); 2452c4088ebdSKirill A. Shutemov spin_lock(pmd_ptl); 2453ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 24547c342512SAneesh Kumar K.V /* 24557c342512SAneesh Kumar K.V * We can only use set_pmd_at when establishing 24567c342512SAneesh Kumar K.V * hugepmds and never for establishing regular pmds that 24577c342512SAneesh Kumar K.V * points to regular pagetables. Use pmd_populate for that 24587c342512SAneesh Kumar K.V */ 24597c342512SAneesh Kumar K.V pmd_populate(mm, pmd, pmd_pgtable(_pmd)); 2460c4088ebdSKirill A. Shutemov spin_unlock(pmd_ptl); 246108b52706SKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2462ce83d217SAndrea Arcangeli goto out; 2463ba76149fSAndrea Arcangeli } 2464ba76149fSAndrea Arcangeli 2465ba76149fSAndrea Arcangeli /* 2466ba76149fSAndrea Arcangeli * All pages are isolated and locked so anon_vma rmap 2467ba76149fSAndrea Arcangeli * can't run anymore. 2468ba76149fSAndrea Arcangeli */ 246908b52706SKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2470ba76149fSAndrea Arcangeli 2471c4088ebdSKirill A. Shutemov __collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl); 2472453c7192SJohannes Weiner pte_unmap(pte); 2473ba76149fSAndrea Arcangeli __SetPageUptodate(new_page); 2474ba76149fSAndrea Arcangeli pgtable = pmd_pgtable(_pmd); 2475ba76149fSAndrea Arcangeli 24763122359aSKirill A. Shutemov _pmd = mk_huge_pmd(new_page, vma->vm_page_prot); 24773122359aSKirill A. Shutemov _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); 2478ba76149fSAndrea Arcangeli 2479ba76149fSAndrea Arcangeli /* 2480ba76149fSAndrea Arcangeli * spin_lock() below is not the equivalent of smp_wmb(), so 2481ba76149fSAndrea Arcangeli * this is needed to avoid the copy_huge_page writes to become 2482ba76149fSAndrea Arcangeli * visible after the set_pmd_at() write. 2483ba76149fSAndrea Arcangeli */ 2484ba76149fSAndrea Arcangeli smp_wmb(); 2485ba76149fSAndrea Arcangeli 2486c4088ebdSKirill A. Shutemov spin_lock(pmd_ptl); 2487ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 2488ba76149fSAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, address); 2489fce144b4SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 2490ba76149fSAndrea Arcangeli set_pmd_at(mm, address, pmd, _pmd); 2491b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 2492c4088ebdSKirill A. Shutemov spin_unlock(pmd_ptl); 2493ba76149fSAndrea Arcangeli 2494ba76149fSAndrea Arcangeli *hpage = NULL; 2495420256efSXiao Guangrong 2496ba76149fSAndrea Arcangeli khugepaged_pages_collapsed++; 2497ce83d217SAndrea Arcangeli out_up_write: 2498ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 24990bbbc0b3SAndrea Arcangeli return; 25000bbbc0b3SAndrea Arcangeli 2501ce83d217SAndrea Arcangeli out: 2502678ff896SKAMEZAWA Hiroyuki mem_cgroup_uncharge_page(new_page); 2503ce83d217SAndrea Arcangeli goto out_up_write; 2504ba76149fSAndrea Arcangeli } 2505ba76149fSAndrea Arcangeli 2506ba76149fSAndrea Arcangeli static int khugepaged_scan_pmd(struct mm_struct *mm, 2507ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 2508ba76149fSAndrea Arcangeli unsigned long address, 2509ba76149fSAndrea Arcangeli struct page **hpage) 2510ba76149fSAndrea Arcangeli { 2511ba76149fSAndrea Arcangeli pmd_t *pmd; 2512ba76149fSAndrea Arcangeli pte_t *pte, *_pte; 2513ba76149fSAndrea Arcangeli int ret = 0, referenced = 0, none = 0; 2514ba76149fSAndrea Arcangeli struct page *page; 2515ba76149fSAndrea Arcangeli unsigned long _address; 2516ba76149fSAndrea Arcangeli spinlock_t *ptl; 251700ef2d2fSDavid Rientjes int node = NUMA_NO_NODE; 2518ba76149fSAndrea Arcangeli 2519ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 2520ba76149fSAndrea Arcangeli 25216219049aSBob Liu pmd = mm_find_pmd(mm, address); 25226219049aSBob Liu if (!pmd) 2523ba76149fSAndrea Arcangeli goto out; 2524ba76149fSAndrea Arcangeli 25259f1b868aSBob Liu memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load)); 2526ba76149fSAndrea Arcangeli pte = pte_offset_map_lock(mm, pmd, address, &ptl); 2527ba76149fSAndrea Arcangeli for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; 2528ba76149fSAndrea Arcangeli _pte++, _address += PAGE_SIZE) { 2529ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2530ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 2531ba76149fSAndrea Arcangeli if (++none <= khugepaged_max_ptes_none) 2532ba76149fSAndrea Arcangeli continue; 2533ba76149fSAndrea Arcangeli else 2534ba76149fSAndrea Arcangeli goto out_unmap; 2535ba76149fSAndrea Arcangeli } 2536ba76149fSAndrea Arcangeli if (!pte_present(pteval) || !pte_write(pteval)) 2537ba76149fSAndrea Arcangeli goto out_unmap; 2538ba76149fSAndrea Arcangeli page = vm_normal_page(vma, _address, pteval); 2539ba76149fSAndrea Arcangeli if (unlikely(!page)) 2540ba76149fSAndrea Arcangeli goto out_unmap; 25415c4b4be3SAndi Kleen /* 25429f1b868aSBob Liu * Record which node the original page is from and save this 25439f1b868aSBob Liu * information to khugepaged_node_load[]. 25449f1b868aSBob Liu * Khupaged will allocate hugepage from the node has the max 25459f1b868aSBob Liu * hit record. 25465c4b4be3SAndi Kleen */ 25475c4b4be3SAndi Kleen node = page_to_nid(page); 25489f1b868aSBob Liu khugepaged_node_load[node]++; 2549309381feSSasha Levin VM_BUG_ON_PAGE(PageCompound(page), page); 2550ba76149fSAndrea Arcangeli if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) 2551ba76149fSAndrea Arcangeli goto out_unmap; 2552ba76149fSAndrea Arcangeli /* cannot use mapcount: can't collapse if there's a gup pin */ 2553ba76149fSAndrea Arcangeli if (page_count(page) != 1) 2554ba76149fSAndrea Arcangeli goto out_unmap; 25558ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 25568ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 2557ba76149fSAndrea Arcangeli referenced = 1; 2558ba76149fSAndrea Arcangeli } 2559ba76149fSAndrea Arcangeli if (referenced) 2560ba76149fSAndrea Arcangeli ret = 1; 2561ba76149fSAndrea Arcangeli out_unmap: 2562ba76149fSAndrea Arcangeli pte_unmap_unlock(pte, ptl); 25639f1b868aSBob Liu if (ret) { 25649f1b868aSBob Liu node = khugepaged_find_target_node(); 2565ce83d217SAndrea Arcangeli /* collapse_huge_page will return with the mmap_sem released */ 25665c4b4be3SAndi Kleen collapse_huge_page(mm, address, hpage, vma, node); 25679f1b868aSBob Liu } 2568ba76149fSAndrea Arcangeli out: 2569ba76149fSAndrea Arcangeli return ret; 2570ba76149fSAndrea Arcangeli } 2571ba76149fSAndrea Arcangeli 2572ba76149fSAndrea Arcangeli static void collect_mm_slot(struct mm_slot *mm_slot) 2573ba76149fSAndrea Arcangeli { 2574ba76149fSAndrea Arcangeli struct mm_struct *mm = mm_slot->mm; 2575ba76149fSAndrea Arcangeli 2576b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2577ba76149fSAndrea Arcangeli 2578ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm)) { 2579ba76149fSAndrea Arcangeli /* free mm_slot */ 258043b5fbbdSSasha Levin hash_del(&mm_slot->hash); 2581ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 2582ba76149fSAndrea Arcangeli 2583ba76149fSAndrea Arcangeli /* 2584ba76149fSAndrea Arcangeli * Not strictly needed because the mm exited already. 2585ba76149fSAndrea Arcangeli * 2586ba76149fSAndrea Arcangeli * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 2587ba76149fSAndrea Arcangeli */ 2588ba76149fSAndrea Arcangeli 2589ba76149fSAndrea Arcangeli /* khugepaged_mm_lock actually not necessary for the below */ 2590ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2591ba76149fSAndrea Arcangeli mmdrop(mm); 2592ba76149fSAndrea Arcangeli } 2593ba76149fSAndrea Arcangeli } 2594ba76149fSAndrea Arcangeli 2595ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_mm_slot(unsigned int pages, 2596ba76149fSAndrea Arcangeli struct page **hpage) 25972f1da642SH Hartley Sweeten __releases(&khugepaged_mm_lock) 25982f1da642SH Hartley Sweeten __acquires(&khugepaged_mm_lock) 2599ba76149fSAndrea Arcangeli { 2600ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2601ba76149fSAndrea Arcangeli struct mm_struct *mm; 2602ba76149fSAndrea Arcangeli struct vm_area_struct *vma; 2603ba76149fSAndrea Arcangeli int progress = 0; 2604ba76149fSAndrea Arcangeli 2605ba76149fSAndrea Arcangeli VM_BUG_ON(!pages); 2606b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2607ba76149fSAndrea Arcangeli 2608ba76149fSAndrea Arcangeli if (khugepaged_scan.mm_slot) 2609ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2610ba76149fSAndrea Arcangeli else { 2611ba76149fSAndrea Arcangeli mm_slot = list_entry(khugepaged_scan.mm_head.next, 2612ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2613ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2614ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = mm_slot; 2615ba76149fSAndrea Arcangeli } 2616ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2617ba76149fSAndrea Arcangeli 2618ba76149fSAndrea Arcangeli mm = mm_slot->mm; 2619ba76149fSAndrea Arcangeli down_read(&mm->mmap_sem); 2620ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2621ba76149fSAndrea Arcangeli vma = NULL; 2622ba76149fSAndrea Arcangeli else 2623ba76149fSAndrea Arcangeli vma = find_vma(mm, khugepaged_scan.address); 2624ba76149fSAndrea Arcangeli 2625ba76149fSAndrea Arcangeli progress++; 2626ba76149fSAndrea Arcangeli for (; vma; vma = vma->vm_next) { 2627ba76149fSAndrea Arcangeli unsigned long hstart, hend; 2628ba76149fSAndrea Arcangeli 2629ba76149fSAndrea Arcangeli cond_resched(); 2630ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) { 2631ba76149fSAndrea Arcangeli progress++; 2632ba76149fSAndrea Arcangeli break; 2633ba76149fSAndrea Arcangeli } 2634fa475e51SBob Liu if (!hugepage_vma_check(vma)) { 2635a7d6e4ecSAndrea Arcangeli skip: 2636ba76149fSAndrea Arcangeli progress++; 2637ba76149fSAndrea Arcangeli continue; 2638ba76149fSAndrea Arcangeli } 2639ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2640ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2641a7d6e4ecSAndrea Arcangeli if (hstart >= hend) 2642a7d6e4ecSAndrea Arcangeli goto skip; 2643a7d6e4ecSAndrea Arcangeli if (khugepaged_scan.address > hend) 2644a7d6e4ecSAndrea Arcangeli goto skip; 2645ba76149fSAndrea Arcangeli if (khugepaged_scan.address < hstart) 2646ba76149fSAndrea Arcangeli khugepaged_scan.address = hstart; 2647a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); 2648ba76149fSAndrea Arcangeli 2649ba76149fSAndrea Arcangeli while (khugepaged_scan.address < hend) { 2650ba76149fSAndrea Arcangeli int ret; 2651ba76149fSAndrea Arcangeli cond_resched(); 2652ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2653ba76149fSAndrea Arcangeli goto breakouterloop; 2654ba76149fSAndrea Arcangeli 2655ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address < hstart || 2656ba76149fSAndrea Arcangeli khugepaged_scan.address + HPAGE_PMD_SIZE > 2657ba76149fSAndrea Arcangeli hend); 2658ba76149fSAndrea Arcangeli ret = khugepaged_scan_pmd(mm, vma, 2659ba76149fSAndrea Arcangeli khugepaged_scan.address, 2660ba76149fSAndrea Arcangeli hpage); 2661ba76149fSAndrea Arcangeli /* move to next address */ 2662ba76149fSAndrea Arcangeli khugepaged_scan.address += HPAGE_PMD_SIZE; 2663ba76149fSAndrea Arcangeli progress += HPAGE_PMD_NR; 2664ba76149fSAndrea Arcangeli if (ret) 2665ba76149fSAndrea Arcangeli /* we released mmap_sem so break loop */ 2666ba76149fSAndrea Arcangeli goto breakouterloop_mmap_sem; 2667ba76149fSAndrea Arcangeli if (progress >= pages) 2668ba76149fSAndrea Arcangeli goto breakouterloop; 2669ba76149fSAndrea Arcangeli } 2670ba76149fSAndrea Arcangeli } 2671ba76149fSAndrea Arcangeli breakouterloop: 2672ba76149fSAndrea Arcangeli up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ 2673ba76149fSAndrea Arcangeli breakouterloop_mmap_sem: 2674ba76149fSAndrea Arcangeli 2675ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2676a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); 2677ba76149fSAndrea Arcangeli /* 2678ba76149fSAndrea Arcangeli * Release the current mm_slot if this mm is about to die, or 2679ba76149fSAndrea Arcangeli * if we scanned all vmas of this mm. 2680ba76149fSAndrea Arcangeli */ 2681ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm) || !vma) { 2682ba76149fSAndrea Arcangeli /* 2683ba76149fSAndrea Arcangeli * Make sure that if mm_users is reaching zero while 2684ba76149fSAndrea Arcangeli * khugepaged runs here, khugepaged_exit will find 2685ba76149fSAndrea Arcangeli * mm_slot not pointing to the exiting mm. 2686ba76149fSAndrea Arcangeli */ 2687ba76149fSAndrea Arcangeli if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { 2688ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = list_entry( 2689ba76149fSAndrea Arcangeli mm_slot->mm_node.next, 2690ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2691ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2692ba76149fSAndrea Arcangeli } else { 2693ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2694ba76149fSAndrea Arcangeli khugepaged_full_scans++; 2695ba76149fSAndrea Arcangeli } 2696ba76149fSAndrea Arcangeli 2697ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2698ba76149fSAndrea Arcangeli } 2699ba76149fSAndrea Arcangeli 2700ba76149fSAndrea Arcangeli return progress; 2701ba76149fSAndrea Arcangeli } 2702ba76149fSAndrea Arcangeli 2703ba76149fSAndrea Arcangeli static int khugepaged_has_work(void) 2704ba76149fSAndrea Arcangeli { 2705ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) && 2706ba76149fSAndrea Arcangeli khugepaged_enabled(); 2707ba76149fSAndrea Arcangeli } 2708ba76149fSAndrea Arcangeli 2709ba76149fSAndrea Arcangeli static int khugepaged_wait_event(void) 2710ba76149fSAndrea Arcangeli { 2711ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) || 27122017c0bfSXiao Guangrong kthread_should_stop(); 2713ba76149fSAndrea Arcangeli } 2714ba76149fSAndrea Arcangeli 2715d516904bSXiao Guangrong static void khugepaged_do_scan(void) 2716d516904bSXiao Guangrong { 2717d516904bSXiao Guangrong struct page *hpage = NULL; 2718ba76149fSAndrea Arcangeli unsigned int progress = 0, pass_through_head = 0; 2719ba76149fSAndrea Arcangeli unsigned int pages = khugepaged_pages_to_scan; 2720d516904bSXiao Guangrong bool wait = true; 2721ba76149fSAndrea Arcangeli 2722ba76149fSAndrea Arcangeli barrier(); /* write khugepaged_pages_to_scan to local stack */ 2723ba76149fSAndrea Arcangeli 2724ba76149fSAndrea Arcangeli while (progress < pages) { 272526234f36SXiao Guangrong if (!khugepaged_prealloc_page(&hpage, &wait)) 272626234f36SXiao Guangrong break; 2727d516904bSXiao Guangrong 2728420256efSXiao Guangrong cond_resched(); 2729ba76149fSAndrea Arcangeli 2730878aee7dSAndrea Arcangeli if (unlikely(kthread_should_stop() || freezing(current))) 2731878aee7dSAndrea Arcangeli break; 2732878aee7dSAndrea Arcangeli 2733ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2734ba76149fSAndrea Arcangeli if (!khugepaged_scan.mm_slot) 2735ba76149fSAndrea Arcangeli pass_through_head++; 2736ba76149fSAndrea Arcangeli if (khugepaged_has_work() && 2737ba76149fSAndrea Arcangeli pass_through_head < 2) 2738ba76149fSAndrea Arcangeli progress += khugepaged_scan_mm_slot(pages - progress, 2739d516904bSXiao Guangrong &hpage); 2740ba76149fSAndrea Arcangeli else 2741ba76149fSAndrea Arcangeli progress = pages; 2742ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2743ba76149fSAndrea Arcangeli } 2744ba76149fSAndrea Arcangeli 2745d516904bSXiao Guangrong if (!IS_ERR_OR_NULL(hpage)) 2746d516904bSXiao Guangrong put_page(hpage); 2747ba76149fSAndrea Arcangeli } 27480bbbc0b3SAndrea Arcangeli 27492017c0bfSXiao Guangrong static void khugepaged_wait_work(void) 27502017c0bfSXiao Guangrong { 27512017c0bfSXiao Guangrong try_to_freeze(); 27522017c0bfSXiao Guangrong 27532017c0bfSXiao Guangrong if (khugepaged_has_work()) { 27542017c0bfSXiao Guangrong if (!khugepaged_scan_sleep_millisecs) 27552017c0bfSXiao Guangrong return; 27562017c0bfSXiao Guangrong 27572017c0bfSXiao Guangrong wait_event_freezable_timeout(khugepaged_wait, 27582017c0bfSXiao Guangrong kthread_should_stop(), 27592017c0bfSXiao Guangrong msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); 27602017c0bfSXiao Guangrong return; 27612017c0bfSXiao Guangrong } 27622017c0bfSXiao Guangrong 27632017c0bfSXiao Guangrong if (khugepaged_enabled()) 27642017c0bfSXiao Guangrong wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); 27652017c0bfSXiao Guangrong } 27662017c0bfSXiao Guangrong 2767ba76149fSAndrea Arcangeli static int khugepaged(void *none) 2768ba76149fSAndrea Arcangeli { 2769ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2770ba76149fSAndrea Arcangeli 2771878aee7dSAndrea Arcangeli set_freezable(); 27728698a745SDongsheng Yang set_user_nice(current, MAX_NICE); 2773ba76149fSAndrea Arcangeli 2774b7231789SXiao Guangrong while (!kthread_should_stop()) { 2775b7231789SXiao Guangrong khugepaged_do_scan(); 2776b7231789SXiao Guangrong khugepaged_wait_work(); 2777b7231789SXiao Guangrong } 2778ba76149fSAndrea Arcangeli 2779ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2780ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2781ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2782ba76149fSAndrea Arcangeli if (mm_slot) 2783ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2784ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2785ba76149fSAndrea Arcangeli return 0; 2786ba76149fSAndrea Arcangeli } 2787ba76149fSAndrea Arcangeli 2788c5a647d0SKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2789c5a647d0SKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2790c5a647d0SKirill A. Shutemov { 2791c5a647d0SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2792c5a647d0SKirill A. Shutemov pgtable_t pgtable; 2793c5a647d0SKirill A. Shutemov pmd_t _pmd; 2794c5a647d0SKirill A. Shutemov int i; 2795c5a647d0SKirill A. Shutemov 2796c5a647d0SKirill A. Shutemov pmdp_clear_flush(vma, haddr, pmd); 2797c5a647d0SKirill A. Shutemov /* leave pmd empty until pte is filled */ 2798c5a647d0SKirill A. Shutemov 27996b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2800c5a647d0SKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2801c5a647d0SKirill A. Shutemov 2802c5a647d0SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 2803c5a647d0SKirill A. Shutemov pte_t *pte, entry; 2804c5a647d0SKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 2805c5a647d0SKirill A. Shutemov entry = pte_mkspecial(entry); 2806c5a647d0SKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 2807c5a647d0SKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 2808c5a647d0SKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 2809c5a647d0SKirill A. Shutemov pte_unmap(pte); 2810c5a647d0SKirill A. Shutemov } 2811c5a647d0SKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2812c5a647d0SKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 281397ae1749SKirill A. Shutemov put_huge_zero_page(); 2814c5a647d0SKirill A. Shutemov } 2815c5a647d0SKirill A. Shutemov 2816e180377fSKirill A. Shutemov void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, 2817e180377fSKirill A. Shutemov pmd_t *pmd) 281871e3aac0SAndrea Arcangeli { 2819c4088ebdSKirill A. Shutemov spinlock_t *ptl; 282071e3aac0SAndrea Arcangeli struct page *page; 2821e180377fSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2822c5a647d0SKirill A. Shutemov unsigned long haddr = address & HPAGE_PMD_MASK; 2823c5a647d0SKirill A. Shutemov unsigned long mmun_start; /* For mmu_notifiers */ 2824c5a647d0SKirill A. Shutemov unsigned long mmun_end; /* For mmu_notifiers */ 2825e180377fSKirill A. Shutemov 2826e180377fSKirill A. Shutemov BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); 282771e3aac0SAndrea Arcangeli 2828c5a647d0SKirill A. Shutemov mmun_start = haddr; 2829c5a647d0SKirill A. Shutemov mmun_end = haddr + HPAGE_PMD_SIZE; 2830750e8165SHugh Dickins again: 2831c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2832c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 283371e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(*pmd))) { 2834c4088ebdSKirill A. Shutemov spin_unlock(ptl); 2835c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2836c5a647d0SKirill A. Shutemov return; 2837c5a647d0SKirill A. Shutemov } 2838c5a647d0SKirill A. Shutemov if (is_huge_zero_pmd(*pmd)) { 2839c5a647d0SKirill A. Shutemov __split_huge_zero_page_pmd(vma, haddr, pmd); 2840c4088ebdSKirill A. Shutemov spin_unlock(ptl); 2841c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 284271e3aac0SAndrea Arcangeli return; 284371e3aac0SAndrea Arcangeli } 284471e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 2845309381feSSasha Levin VM_BUG_ON_PAGE(!page_count(page), page); 284671e3aac0SAndrea Arcangeli get_page(page); 2847c4088ebdSKirill A. Shutemov spin_unlock(ptl); 2848c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 284971e3aac0SAndrea Arcangeli 285071e3aac0SAndrea Arcangeli split_huge_page(page); 285171e3aac0SAndrea Arcangeli 285271e3aac0SAndrea Arcangeli put_page(page); 2853750e8165SHugh Dickins 2854750e8165SHugh Dickins /* 2855750e8165SHugh Dickins * We don't always have down_write of mmap_sem here: a racing 2856750e8165SHugh Dickins * do_huge_pmd_wp_page() might have copied-on-write to another 2857750e8165SHugh Dickins * huge page before our split_huge_page() got the anon_vma lock. 2858750e8165SHugh Dickins */ 2859750e8165SHugh Dickins if (unlikely(pmd_trans_huge(*pmd))) 2860750e8165SHugh Dickins goto again; 286171e3aac0SAndrea Arcangeli } 286294fcc585SAndrea Arcangeli 2863e180377fSKirill A. Shutemov void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, 2864e180377fSKirill A. Shutemov pmd_t *pmd) 2865e180377fSKirill A. Shutemov { 2866e180377fSKirill A. Shutemov struct vm_area_struct *vma; 2867e180377fSKirill A. Shutemov 2868e180377fSKirill A. Shutemov vma = find_vma(mm, address); 2869e180377fSKirill A. Shutemov BUG_ON(vma == NULL); 2870e180377fSKirill A. Shutemov split_huge_page_pmd(vma, address, pmd); 2871e180377fSKirill A. Shutemov } 2872e180377fSKirill A. Shutemov 287394fcc585SAndrea Arcangeli static void split_huge_page_address(struct mm_struct *mm, 287494fcc585SAndrea Arcangeli unsigned long address) 287594fcc585SAndrea Arcangeli { 2876*f72e7dcdSHugh Dickins pgd_t *pgd; 2877*f72e7dcdSHugh Dickins pud_t *pud; 287894fcc585SAndrea Arcangeli pmd_t *pmd; 287994fcc585SAndrea Arcangeli 288094fcc585SAndrea Arcangeli VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); 288194fcc585SAndrea Arcangeli 2882*f72e7dcdSHugh Dickins pgd = pgd_offset(mm, address); 2883*f72e7dcdSHugh Dickins if (!pgd_present(*pgd)) 2884*f72e7dcdSHugh Dickins return; 2885*f72e7dcdSHugh Dickins 2886*f72e7dcdSHugh Dickins pud = pud_offset(pgd, address); 2887*f72e7dcdSHugh Dickins if (!pud_present(*pud)) 2888*f72e7dcdSHugh Dickins return; 2889*f72e7dcdSHugh Dickins 2890*f72e7dcdSHugh Dickins pmd = pmd_offset(pud, address); 2891*f72e7dcdSHugh Dickins if (!pmd_present(*pmd)) 289294fcc585SAndrea Arcangeli return; 289394fcc585SAndrea Arcangeli /* 289494fcc585SAndrea Arcangeli * Caller holds the mmap_sem write mode, so a huge pmd cannot 289594fcc585SAndrea Arcangeli * materialize from under us. 289694fcc585SAndrea Arcangeli */ 2897e180377fSKirill A. Shutemov split_huge_page_pmd_mm(mm, address, pmd); 289894fcc585SAndrea Arcangeli } 289994fcc585SAndrea Arcangeli 290094fcc585SAndrea Arcangeli void __vma_adjust_trans_huge(struct vm_area_struct *vma, 290194fcc585SAndrea Arcangeli unsigned long start, 290294fcc585SAndrea Arcangeli unsigned long end, 290394fcc585SAndrea Arcangeli long adjust_next) 290494fcc585SAndrea Arcangeli { 290594fcc585SAndrea Arcangeli /* 290694fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 290794fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 290894fcc585SAndrea Arcangeli * an huge pmd. 290994fcc585SAndrea Arcangeli */ 291094fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 291194fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 291294fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 291394fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, start); 291494fcc585SAndrea Arcangeli 291594fcc585SAndrea Arcangeli /* 291694fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 291794fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 291894fcc585SAndrea Arcangeli * an huge pmd. 291994fcc585SAndrea Arcangeli */ 292094fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 292194fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 292294fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 292394fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, end); 292494fcc585SAndrea Arcangeli 292594fcc585SAndrea Arcangeli /* 292694fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 292794fcc585SAndrea Arcangeli * vm_next->vm_start isn't page aligned and it could previously 292894fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 292994fcc585SAndrea Arcangeli */ 293094fcc585SAndrea Arcangeli if (adjust_next > 0) { 293194fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 293294fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 293394fcc585SAndrea Arcangeli nstart += adjust_next << PAGE_SHIFT; 293494fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 293594fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 293694fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 293794fcc585SAndrea Arcangeli split_huge_page_address(next->vm_mm, nstart); 293894fcc585SAndrea Arcangeli } 293994fcc585SAndrea Arcangeli } 2940