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> 26*6b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 2797ae1749SKirill A. Shutemov 2871e3aac0SAndrea Arcangeli #include <asm/tlb.h> 2971e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 3071e3aac0SAndrea Arcangeli #include "internal.h" 3171e3aac0SAndrea Arcangeli 32ba76149fSAndrea Arcangeli /* 338bfa3f9aSJianguo Wu * By default transparent hugepage support is disabled in order that avoid 348bfa3f9aSJianguo Wu * to risk increase the memory footprint of applications without a guaranteed 358bfa3f9aSJianguo Wu * benefit. When transparent hugepage support is enabled, is for all mappings, 368bfa3f9aSJianguo Wu * and khugepaged scans all mappings. 378bfa3f9aSJianguo Wu * Defrag is invoked by khugepaged hugepage allocations and by page faults 388bfa3f9aSJianguo Wu * for all hugepage allocations. 39ba76149fSAndrea Arcangeli */ 4071e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 4113ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 42ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 4313ece886SAndrea Arcangeli #endif 4413ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 4513ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 4613ece886SAndrea Arcangeli #endif 47d39d33c3SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| 4879da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 4979da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 50ba76149fSAndrea Arcangeli 51ba76149fSAndrea Arcangeli /* default scan 8*512 pte (or vmas) every 30 second */ 52ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; 53ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_collapsed; 54ba76149fSAndrea Arcangeli static unsigned int khugepaged_full_scans; 55ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; 56ba76149fSAndrea Arcangeli /* during fragmentation poll the hugepage allocator once every minute */ 57ba76149fSAndrea Arcangeli static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; 58ba76149fSAndrea Arcangeli static struct task_struct *khugepaged_thread __read_mostly; 59ba76149fSAndrea Arcangeli static DEFINE_MUTEX(khugepaged_mutex); 60ba76149fSAndrea Arcangeli static DEFINE_SPINLOCK(khugepaged_mm_lock); 61ba76149fSAndrea Arcangeli static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); 62ba76149fSAndrea Arcangeli /* 63ba76149fSAndrea Arcangeli * default collapse hugepages if there is at least one pte mapped like 64ba76149fSAndrea Arcangeli * it would have happened if the vma was large enough during page 65ba76149fSAndrea Arcangeli * fault. 66ba76149fSAndrea Arcangeli */ 67ba76149fSAndrea Arcangeli static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; 68ba76149fSAndrea Arcangeli 69ba76149fSAndrea Arcangeli static int khugepaged(void *none); 70ba76149fSAndrea Arcangeli static int khugepaged_slab_init(void); 7165ebb64fSKirill A. Shutemov static void khugepaged_slab_exit(void); 72ba76149fSAndrea Arcangeli 7343b5fbbdSSasha Levin #define MM_SLOTS_HASH_BITS 10 7443b5fbbdSSasha Levin static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); 7543b5fbbdSSasha Levin 76ba76149fSAndrea Arcangeli static struct kmem_cache *mm_slot_cache __read_mostly; 77ba76149fSAndrea Arcangeli 78ba76149fSAndrea Arcangeli /** 79ba76149fSAndrea Arcangeli * struct mm_slot - hash lookup from mm to mm_slot 80ba76149fSAndrea Arcangeli * @hash: hash collision list 81ba76149fSAndrea Arcangeli * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head 82ba76149fSAndrea Arcangeli * @mm: the mm that this information is valid for 83ba76149fSAndrea Arcangeli */ 84ba76149fSAndrea Arcangeli struct mm_slot { 85ba76149fSAndrea Arcangeli struct hlist_node hash; 86ba76149fSAndrea Arcangeli struct list_head mm_node; 87ba76149fSAndrea Arcangeli struct mm_struct *mm; 88ba76149fSAndrea Arcangeli }; 89ba76149fSAndrea Arcangeli 90ba76149fSAndrea Arcangeli /** 91ba76149fSAndrea Arcangeli * struct khugepaged_scan - cursor for scanning 92ba76149fSAndrea Arcangeli * @mm_head: the head of the mm list to scan 93ba76149fSAndrea Arcangeli * @mm_slot: the current mm_slot we are scanning 94ba76149fSAndrea Arcangeli * @address: the next address inside that to be scanned 95ba76149fSAndrea Arcangeli * 96ba76149fSAndrea Arcangeli * There is only the one khugepaged_scan instance of this cursor structure. 97ba76149fSAndrea Arcangeli */ 98ba76149fSAndrea Arcangeli struct khugepaged_scan { 99ba76149fSAndrea Arcangeli struct list_head mm_head; 100ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 101ba76149fSAndrea Arcangeli unsigned long address; 1022f1da642SH Hartley Sweeten }; 1032f1da642SH Hartley Sweeten static struct khugepaged_scan khugepaged_scan = { 104ba76149fSAndrea Arcangeli .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), 105ba76149fSAndrea Arcangeli }; 106ba76149fSAndrea Arcangeli 107f000565aSAndrea Arcangeli 108f000565aSAndrea Arcangeli static int set_recommended_min_free_kbytes(void) 109f000565aSAndrea Arcangeli { 110f000565aSAndrea Arcangeli struct zone *zone; 111f000565aSAndrea Arcangeli int nr_zones = 0; 112f000565aSAndrea Arcangeli unsigned long recommended_min; 113f000565aSAndrea Arcangeli 114f000565aSAndrea Arcangeli for_each_populated_zone(zone) 115f000565aSAndrea Arcangeli nr_zones++; 116f000565aSAndrea Arcangeli 117f000565aSAndrea Arcangeli /* Make sure at least 2 hugepages are free for MIGRATE_RESERVE */ 118f000565aSAndrea Arcangeli recommended_min = pageblock_nr_pages * nr_zones * 2; 119f000565aSAndrea Arcangeli 120f000565aSAndrea Arcangeli /* 121f000565aSAndrea Arcangeli * Make sure that on average at least two pageblocks are almost free 122f000565aSAndrea Arcangeli * of another type, one for a migratetype to fall back to and a 123f000565aSAndrea Arcangeli * second to avoid subsequent fallbacks of other types There are 3 124f000565aSAndrea Arcangeli * MIGRATE_TYPES we care about. 125f000565aSAndrea Arcangeli */ 126f000565aSAndrea Arcangeli recommended_min += pageblock_nr_pages * nr_zones * 127f000565aSAndrea Arcangeli MIGRATE_PCPTYPES * MIGRATE_PCPTYPES; 128f000565aSAndrea Arcangeli 129f000565aSAndrea Arcangeli /* don't ever allow to reserve more than 5% of the lowmem */ 130f000565aSAndrea Arcangeli recommended_min = min(recommended_min, 131f000565aSAndrea Arcangeli (unsigned long) nr_free_buffer_pages() / 20); 132f000565aSAndrea Arcangeli recommended_min <<= (PAGE_SHIFT-10); 133f000565aSAndrea Arcangeli 13442aa83cbSHan Pingtian if (recommended_min > min_free_kbytes) { 13542aa83cbSHan Pingtian if (user_min_free_kbytes >= 0) 13642aa83cbSHan Pingtian pr_info("raising min_free_kbytes from %d to %lu " 13742aa83cbSHan Pingtian "to help transparent hugepage allocations\n", 13842aa83cbSHan Pingtian min_free_kbytes, recommended_min); 13942aa83cbSHan Pingtian 140f000565aSAndrea Arcangeli min_free_kbytes = recommended_min; 14142aa83cbSHan Pingtian } 142f000565aSAndrea Arcangeli setup_per_zone_wmarks(); 143f000565aSAndrea Arcangeli return 0; 144f000565aSAndrea Arcangeli } 145f000565aSAndrea Arcangeli 14679553da2SKirill A. Shutemov static int start_stop_khugepaged(void) 147ba76149fSAndrea Arcangeli { 148ba76149fSAndrea Arcangeli int err = 0; 149ba76149fSAndrea Arcangeli if (khugepaged_enabled()) { 150ba76149fSAndrea Arcangeli if (!khugepaged_thread) 151ba76149fSAndrea Arcangeli khugepaged_thread = kthread_run(khugepaged, NULL, 152ba76149fSAndrea Arcangeli "khugepaged"); 153ba76149fSAndrea Arcangeli if (unlikely(IS_ERR(khugepaged_thread))) { 154ae3a8c1cSAndrew Morton pr_err("khugepaged: kthread_run(khugepaged) failed\n"); 155ba76149fSAndrea Arcangeli err = PTR_ERR(khugepaged_thread); 156ba76149fSAndrea Arcangeli khugepaged_thread = NULL; 15779553da2SKirill A. Shutemov goto fail; 158ba76149fSAndrea Arcangeli } 159911891afSXiao Guangrong 160911891afSXiao Guangrong if (!list_empty(&khugepaged_scan.mm_head)) 161ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 162f000565aSAndrea Arcangeli 163f000565aSAndrea Arcangeli set_recommended_min_free_kbytes(); 164911891afSXiao Guangrong } else if (khugepaged_thread) { 165911891afSXiao Guangrong kthread_stop(khugepaged_thread); 166911891afSXiao Guangrong khugepaged_thread = NULL; 167911891afSXiao Guangrong } 16879553da2SKirill A. Shutemov fail: 169ba76149fSAndrea Arcangeli return err; 170ba76149fSAndrea Arcangeli } 17171e3aac0SAndrea Arcangeli 17297ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 17356873f43SWang, Yalin struct page *huge_zero_page __read_mostly; 1744a6c1297SKirill A. Shutemov 1754a6c1297SKirill A. Shutemov static inline bool is_huge_zero_pmd(pmd_t pmd) 1764a6c1297SKirill A. Shutemov { 1775918d10aSKirill A. Shutemov return is_huge_zero_page(pmd_page(pmd)); 1784a6c1297SKirill A. Shutemov } 1794a6c1297SKirill A. Shutemov 1805918d10aSKirill A. Shutemov static struct page *get_huge_zero_page(void) 18197ae1749SKirill A. Shutemov { 18297ae1749SKirill A. Shutemov struct page *zero_page; 18397ae1749SKirill A. Shutemov retry: 18497ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 1854db0c3c2SJason Low return READ_ONCE(huge_zero_page); 18697ae1749SKirill A. Shutemov 18797ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 18897ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 189d8a8e1f0SKirill A. Shutemov if (!zero_page) { 190d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 1915918d10aSKirill A. Shutemov return NULL; 192d8a8e1f0SKirill A. Shutemov } 193d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC); 19497ae1749SKirill A. Shutemov preempt_disable(); 1955918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 19697ae1749SKirill A. Shutemov preempt_enable(); 1975ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 19897ae1749SKirill A. Shutemov goto retry; 19997ae1749SKirill A. Shutemov } 20097ae1749SKirill A. Shutemov 20197ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 20297ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 20397ae1749SKirill A. Shutemov preempt_enable(); 2044db0c3c2SJason Low return READ_ONCE(huge_zero_page); 20597ae1749SKirill A. Shutemov } 20697ae1749SKirill A. Shutemov 20797ae1749SKirill A. Shutemov static void put_huge_zero_page(void) 20897ae1749SKirill A. Shutemov { 20997ae1749SKirill A. Shutemov /* 21097ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 21197ae1749SKirill A. Shutemov * last reference. 21297ae1749SKirill A. Shutemov */ 21397ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 21497ae1749SKirill A. Shutemov } 21597ae1749SKirill A. Shutemov 21648896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 21797ae1749SKirill A. Shutemov struct shrink_control *sc) 21897ae1749SKirill A. Shutemov { 21997ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 22097ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 22148896466SGlauber Costa } 22297ae1749SKirill A. Shutemov 22348896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 22448896466SGlauber Costa struct shrink_control *sc) 22548896466SGlauber Costa { 22697ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2275918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2285918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2295ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 23048896466SGlauber Costa return HPAGE_PMD_NR; 23197ae1749SKirill A. Shutemov } 23297ae1749SKirill A. Shutemov 23397ae1749SKirill A. Shutemov return 0; 23497ae1749SKirill A. Shutemov } 23597ae1749SKirill A. Shutemov 23697ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 23748896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 23848896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 23997ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 24097ae1749SKirill A. Shutemov }; 24197ae1749SKirill A. Shutemov 24271e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 243ba76149fSAndrea Arcangeli 24471e3aac0SAndrea Arcangeli static ssize_t double_flag_show(struct kobject *kobj, 24571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 24671e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 24771e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 24871e3aac0SAndrea Arcangeli { 24971e3aac0SAndrea Arcangeli if (test_bit(enabled, &transparent_hugepage_flags)) { 25071e3aac0SAndrea Arcangeli VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); 25171e3aac0SAndrea Arcangeli return sprintf(buf, "[always] madvise never\n"); 25271e3aac0SAndrea Arcangeli } else if (test_bit(req_madv, &transparent_hugepage_flags)) 25371e3aac0SAndrea Arcangeli return sprintf(buf, "always [madvise] never\n"); 25471e3aac0SAndrea Arcangeli else 25571e3aac0SAndrea Arcangeli return sprintf(buf, "always madvise [never]\n"); 25671e3aac0SAndrea Arcangeli } 25771e3aac0SAndrea Arcangeli static ssize_t double_flag_store(struct kobject *kobj, 25871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 25971e3aac0SAndrea Arcangeli const char *buf, size_t count, 26071e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 26171e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 26271e3aac0SAndrea Arcangeli { 26371e3aac0SAndrea Arcangeli if (!memcmp("always", buf, 26471e3aac0SAndrea Arcangeli min(sizeof("always")-1, count))) { 26571e3aac0SAndrea Arcangeli set_bit(enabled, &transparent_hugepage_flags); 26671e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 26771e3aac0SAndrea Arcangeli } else if (!memcmp("madvise", buf, 26871e3aac0SAndrea Arcangeli min(sizeof("madvise")-1, count))) { 26971e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 27071e3aac0SAndrea Arcangeli set_bit(req_madv, &transparent_hugepage_flags); 27171e3aac0SAndrea Arcangeli } else if (!memcmp("never", buf, 27271e3aac0SAndrea Arcangeli min(sizeof("never")-1, count))) { 27371e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 27471e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 27571e3aac0SAndrea Arcangeli } else 27671e3aac0SAndrea Arcangeli return -EINVAL; 27771e3aac0SAndrea Arcangeli 27871e3aac0SAndrea Arcangeli return count; 27971e3aac0SAndrea Arcangeli } 28071e3aac0SAndrea Arcangeli 28171e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 28271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 28371e3aac0SAndrea Arcangeli { 28471e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 28571e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 28671e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 28771e3aac0SAndrea Arcangeli } 28871e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 28971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 29071e3aac0SAndrea Arcangeli const char *buf, size_t count) 29171e3aac0SAndrea Arcangeli { 292ba76149fSAndrea Arcangeli ssize_t ret; 293ba76149fSAndrea Arcangeli 294ba76149fSAndrea Arcangeli ret = double_flag_store(kobj, attr, buf, count, 29571e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 29671e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 297ba76149fSAndrea Arcangeli 298ba76149fSAndrea Arcangeli if (ret > 0) { 299911891afSXiao Guangrong int err; 300911891afSXiao Guangrong 301911891afSXiao Guangrong mutex_lock(&khugepaged_mutex); 30279553da2SKirill A. Shutemov err = start_stop_khugepaged(); 303911891afSXiao Guangrong mutex_unlock(&khugepaged_mutex); 304911891afSXiao Guangrong 305ba76149fSAndrea Arcangeli if (err) 306ba76149fSAndrea Arcangeli ret = err; 307ba76149fSAndrea Arcangeli } 308ba76149fSAndrea Arcangeli 309ba76149fSAndrea Arcangeli return ret; 31071e3aac0SAndrea Arcangeli } 31171e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 31271e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 31371e3aac0SAndrea Arcangeli 31471e3aac0SAndrea Arcangeli static ssize_t single_flag_show(struct kobject *kobj, 31571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 31671e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 31771e3aac0SAndrea Arcangeli { 318e27e6151SBen Hutchings return sprintf(buf, "%d\n", 319e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 32071e3aac0SAndrea Arcangeli } 321e27e6151SBen Hutchings 32271e3aac0SAndrea Arcangeli static ssize_t single_flag_store(struct kobject *kobj, 32371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 32471e3aac0SAndrea Arcangeli const char *buf, size_t count, 32571e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 32671e3aac0SAndrea Arcangeli { 327e27e6151SBen Hutchings unsigned long value; 328e27e6151SBen Hutchings int ret; 329e27e6151SBen Hutchings 330e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 331e27e6151SBen Hutchings if (ret < 0) 332e27e6151SBen Hutchings return ret; 333e27e6151SBen Hutchings if (value > 1) 33471e3aac0SAndrea Arcangeli return -EINVAL; 33571e3aac0SAndrea Arcangeli 336e27e6151SBen Hutchings if (value) 337e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 338e27e6151SBen Hutchings else 339e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 340e27e6151SBen Hutchings 34171e3aac0SAndrea Arcangeli return count; 34271e3aac0SAndrea Arcangeli } 34371e3aac0SAndrea Arcangeli 34471e3aac0SAndrea Arcangeli /* 34571e3aac0SAndrea Arcangeli * Currently defrag only disables __GFP_NOWAIT for allocation. A blind 34671e3aac0SAndrea Arcangeli * __GFP_REPEAT is too aggressive, it's never worth swapping tons of 34771e3aac0SAndrea Arcangeli * memory just to allocate one more hugepage. 34871e3aac0SAndrea Arcangeli */ 34971e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 35071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 35171e3aac0SAndrea Arcangeli { 35271e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 35371e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 35471e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 35571e3aac0SAndrea Arcangeli } 35671e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 35771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 35871e3aac0SAndrea Arcangeli const char *buf, size_t count) 35971e3aac0SAndrea Arcangeli { 36071e3aac0SAndrea Arcangeli return double_flag_store(kobj, attr, buf, count, 36171e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 36271e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 36371e3aac0SAndrea Arcangeli } 36471e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 36571e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 36671e3aac0SAndrea Arcangeli 36779da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 36879da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 36979da5407SKirill A. Shutemov { 37079da5407SKirill A. Shutemov return single_flag_show(kobj, attr, buf, 37179da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 37279da5407SKirill A. Shutemov } 37379da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 37479da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 37579da5407SKirill A. Shutemov { 37679da5407SKirill A. Shutemov return single_flag_store(kobj, attr, buf, count, 37779da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 37879da5407SKirill A. Shutemov } 37979da5407SKirill A. Shutemov static struct kobj_attribute use_zero_page_attr = 38079da5407SKirill A. Shutemov __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); 38171e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 38271e3aac0SAndrea Arcangeli static ssize_t debug_cow_show(struct kobject *kobj, 38371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 38471e3aac0SAndrea Arcangeli { 38571e3aac0SAndrea Arcangeli return single_flag_show(kobj, attr, buf, 38671e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 38771e3aac0SAndrea Arcangeli } 38871e3aac0SAndrea Arcangeli static ssize_t debug_cow_store(struct kobject *kobj, 38971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 39071e3aac0SAndrea Arcangeli const char *buf, size_t count) 39171e3aac0SAndrea Arcangeli { 39271e3aac0SAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 39371e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 39471e3aac0SAndrea Arcangeli } 39571e3aac0SAndrea Arcangeli static struct kobj_attribute debug_cow_attr = 39671e3aac0SAndrea Arcangeli __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); 39771e3aac0SAndrea Arcangeli #endif /* CONFIG_DEBUG_VM */ 39871e3aac0SAndrea Arcangeli 39971e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 40071e3aac0SAndrea Arcangeli &enabled_attr.attr, 40171e3aac0SAndrea Arcangeli &defrag_attr.attr, 40279da5407SKirill A. Shutemov &use_zero_page_attr.attr, 40371e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 40471e3aac0SAndrea Arcangeli &debug_cow_attr.attr, 40571e3aac0SAndrea Arcangeli #endif 40671e3aac0SAndrea Arcangeli NULL, 40771e3aac0SAndrea Arcangeli }; 40871e3aac0SAndrea Arcangeli 40971e3aac0SAndrea Arcangeli static struct attribute_group hugepage_attr_group = { 41071e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 411ba76149fSAndrea Arcangeli }; 412ba76149fSAndrea Arcangeli 413ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, 414ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 415ba76149fSAndrea Arcangeli char *buf) 416ba76149fSAndrea Arcangeli { 417ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); 418ba76149fSAndrea Arcangeli } 419ba76149fSAndrea Arcangeli 420ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, 421ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 422ba76149fSAndrea Arcangeli const char *buf, size_t count) 423ba76149fSAndrea Arcangeli { 424ba76149fSAndrea Arcangeli unsigned long msecs; 425ba76149fSAndrea Arcangeli int err; 426ba76149fSAndrea Arcangeli 4273dbb95f7SJingoo Han err = kstrtoul(buf, 10, &msecs); 428ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 429ba76149fSAndrea Arcangeli return -EINVAL; 430ba76149fSAndrea Arcangeli 431ba76149fSAndrea Arcangeli khugepaged_scan_sleep_millisecs = msecs; 432ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 433ba76149fSAndrea Arcangeli 434ba76149fSAndrea Arcangeli return count; 435ba76149fSAndrea Arcangeli } 436ba76149fSAndrea Arcangeli static struct kobj_attribute scan_sleep_millisecs_attr = 437ba76149fSAndrea Arcangeli __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, 438ba76149fSAndrea Arcangeli scan_sleep_millisecs_store); 439ba76149fSAndrea Arcangeli 440ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, 441ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 442ba76149fSAndrea Arcangeli char *buf) 443ba76149fSAndrea Arcangeli { 444ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); 445ba76149fSAndrea Arcangeli } 446ba76149fSAndrea Arcangeli 447ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, 448ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 449ba76149fSAndrea Arcangeli const char *buf, size_t count) 450ba76149fSAndrea Arcangeli { 451ba76149fSAndrea Arcangeli unsigned long msecs; 452ba76149fSAndrea Arcangeli int err; 453ba76149fSAndrea Arcangeli 4543dbb95f7SJingoo Han err = kstrtoul(buf, 10, &msecs); 455ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 456ba76149fSAndrea Arcangeli return -EINVAL; 457ba76149fSAndrea Arcangeli 458ba76149fSAndrea Arcangeli khugepaged_alloc_sleep_millisecs = msecs; 459ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 460ba76149fSAndrea Arcangeli 461ba76149fSAndrea Arcangeli return count; 462ba76149fSAndrea Arcangeli } 463ba76149fSAndrea Arcangeli static struct kobj_attribute alloc_sleep_millisecs_attr = 464ba76149fSAndrea Arcangeli __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, 465ba76149fSAndrea Arcangeli alloc_sleep_millisecs_store); 466ba76149fSAndrea Arcangeli 467ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_show(struct kobject *kobj, 468ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 469ba76149fSAndrea Arcangeli char *buf) 470ba76149fSAndrea Arcangeli { 471ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_to_scan); 472ba76149fSAndrea Arcangeli } 473ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_store(struct kobject *kobj, 474ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 475ba76149fSAndrea Arcangeli const char *buf, size_t count) 476ba76149fSAndrea Arcangeli { 477ba76149fSAndrea Arcangeli int err; 478ba76149fSAndrea Arcangeli unsigned long pages; 479ba76149fSAndrea Arcangeli 4803dbb95f7SJingoo Han err = kstrtoul(buf, 10, &pages); 481ba76149fSAndrea Arcangeli if (err || !pages || pages > UINT_MAX) 482ba76149fSAndrea Arcangeli return -EINVAL; 483ba76149fSAndrea Arcangeli 484ba76149fSAndrea Arcangeli khugepaged_pages_to_scan = pages; 485ba76149fSAndrea Arcangeli 486ba76149fSAndrea Arcangeli return count; 487ba76149fSAndrea Arcangeli } 488ba76149fSAndrea Arcangeli static struct kobj_attribute pages_to_scan_attr = 489ba76149fSAndrea Arcangeli __ATTR(pages_to_scan, 0644, pages_to_scan_show, 490ba76149fSAndrea Arcangeli pages_to_scan_store); 491ba76149fSAndrea Arcangeli 492ba76149fSAndrea Arcangeli static ssize_t pages_collapsed_show(struct kobject *kobj, 493ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 494ba76149fSAndrea Arcangeli char *buf) 495ba76149fSAndrea Arcangeli { 496ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_collapsed); 497ba76149fSAndrea Arcangeli } 498ba76149fSAndrea Arcangeli static struct kobj_attribute pages_collapsed_attr = 499ba76149fSAndrea Arcangeli __ATTR_RO(pages_collapsed); 500ba76149fSAndrea Arcangeli 501ba76149fSAndrea Arcangeli static ssize_t full_scans_show(struct kobject *kobj, 502ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 503ba76149fSAndrea Arcangeli char *buf) 504ba76149fSAndrea Arcangeli { 505ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_full_scans); 506ba76149fSAndrea Arcangeli } 507ba76149fSAndrea Arcangeli static struct kobj_attribute full_scans_attr = 508ba76149fSAndrea Arcangeli __ATTR_RO(full_scans); 509ba76149fSAndrea Arcangeli 510ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_show(struct kobject *kobj, 511ba76149fSAndrea Arcangeli struct kobj_attribute *attr, char *buf) 512ba76149fSAndrea Arcangeli { 513ba76149fSAndrea Arcangeli return single_flag_show(kobj, attr, buf, 514ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 515ba76149fSAndrea Arcangeli } 516ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_store(struct kobject *kobj, 517ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 518ba76149fSAndrea Arcangeli const char *buf, size_t count) 519ba76149fSAndrea Arcangeli { 520ba76149fSAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 521ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 522ba76149fSAndrea Arcangeli } 523ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_defrag_attr = 524ba76149fSAndrea Arcangeli __ATTR(defrag, 0644, khugepaged_defrag_show, 525ba76149fSAndrea Arcangeli khugepaged_defrag_store); 526ba76149fSAndrea Arcangeli 527ba76149fSAndrea Arcangeli /* 528ba76149fSAndrea Arcangeli * max_ptes_none controls if khugepaged should collapse hugepages over 529ba76149fSAndrea Arcangeli * any unmapped ptes in turn potentially increasing the memory 530ba76149fSAndrea Arcangeli * footprint of the vmas. When max_ptes_none is 0 khugepaged will not 531ba76149fSAndrea Arcangeli * reduce the available free memory in the system as it 532ba76149fSAndrea Arcangeli * runs. Increasing max_ptes_none will instead potentially reduce the 533ba76149fSAndrea Arcangeli * free memory in the system during the khugepaged scan. 534ba76149fSAndrea Arcangeli */ 535ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, 536ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 537ba76149fSAndrea Arcangeli char *buf) 538ba76149fSAndrea Arcangeli { 539ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_max_ptes_none); 540ba76149fSAndrea Arcangeli } 541ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, 542ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 543ba76149fSAndrea Arcangeli const char *buf, size_t count) 544ba76149fSAndrea Arcangeli { 545ba76149fSAndrea Arcangeli int err; 546ba76149fSAndrea Arcangeli unsigned long max_ptes_none; 547ba76149fSAndrea Arcangeli 5483dbb95f7SJingoo Han err = kstrtoul(buf, 10, &max_ptes_none); 549ba76149fSAndrea Arcangeli if (err || max_ptes_none > HPAGE_PMD_NR-1) 550ba76149fSAndrea Arcangeli return -EINVAL; 551ba76149fSAndrea Arcangeli 552ba76149fSAndrea Arcangeli khugepaged_max_ptes_none = max_ptes_none; 553ba76149fSAndrea Arcangeli 554ba76149fSAndrea Arcangeli return count; 555ba76149fSAndrea Arcangeli } 556ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_max_ptes_none_attr = 557ba76149fSAndrea Arcangeli __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, 558ba76149fSAndrea Arcangeli khugepaged_max_ptes_none_store); 559ba76149fSAndrea Arcangeli 560ba76149fSAndrea Arcangeli static struct attribute *khugepaged_attr[] = { 561ba76149fSAndrea Arcangeli &khugepaged_defrag_attr.attr, 562ba76149fSAndrea Arcangeli &khugepaged_max_ptes_none_attr.attr, 563ba76149fSAndrea Arcangeli &pages_to_scan_attr.attr, 564ba76149fSAndrea Arcangeli &pages_collapsed_attr.attr, 565ba76149fSAndrea Arcangeli &full_scans_attr.attr, 566ba76149fSAndrea Arcangeli &scan_sleep_millisecs_attr.attr, 567ba76149fSAndrea Arcangeli &alloc_sleep_millisecs_attr.attr, 568ba76149fSAndrea Arcangeli NULL, 569ba76149fSAndrea Arcangeli }; 570ba76149fSAndrea Arcangeli 571ba76149fSAndrea Arcangeli static struct attribute_group khugepaged_attr_group = { 572ba76149fSAndrea Arcangeli .attrs = khugepaged_attr, 573ba76149fSAndrea Arcangeli .name = "khugepaged", 57471e3aac0SAndrea Arcangeli }; 575569e5590SShaohua Li 576569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 577569e5590SShaohua Li { 578569e5590SShaohua Li int err; 579569e5590SShaohua Li 580569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 581569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 582ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 583569e5590SShaohua Li return -ENOMEM; 584569e5590SShaohua Li } 585569e5590SShaohua Li 586569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 587569e5590SShaohua Li if (err) { 588ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 589569e5590SShaohua Li goto delete_obj; 590569e5590SShaohua Li } 591569e5590SShaohua Li 592569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 593569e5590SShaohua Li if (err) { 594ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 595569e5590SShaohua Li goto remove_hp_group; 596569e5590SShaohua Li } 597569e5590SShaohua Li 598569e5590SShaohua Li return 0; 599569e5590SShaohua Li 600569e5590SShaohua Li remove_hp_group: 601569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 602569e5590SShaohua Li delete_obj: 603569e5590SShaohua Li kobject_put(*hugepage_kobj); 604569e5590SShaohua Li return err; 605569e5590SShaohua Li } 606569e5590SShaohua Li 607569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 608569e5590SShaohua Li { 609569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 610569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 611569e5590SShaohua Li kobject_put(hugepage_kobj); 612569e5590SShaohua Li } 613569e5590SShaohua Li #else 614569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 615569e5590SShaohua Li { 616569e5590SShaohua Li return 0; 617569e5590SShaohua Li } 618569e5590SShaohua Li 619569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 620569e5590SShaohua Li { 621569e5590SShaohua Li } 62271e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 62371e3aac0SAndrea Arcangeli 62471e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 62571e3aac0SAndrea Arcangeli { 62671e3aac0SAndrea Arcangeli int err; 627569e5590SShaohua Li struct kobject *hugepage_kobj; 62871e3aac0SAndrea Arcangeli 6294b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 6304b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 631569e5590SShaohua Li return -EINVAL; 6324b7167b9SAndrea Arcangeli } 6334b7167b9SAndrea Arcangeli 634569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 635569e5590SShaohua Li if (err) 63665ebb64fSKirill A. Shutemov goto err_sysfs; 637ba76149fSAndrea Arcangeli 638ba76149fSAndrea Arcangeli err = khugepaged_slab_init(); 639ba76149fSAndrea Arcangeli if (err) 64065ebb64fSKirill A. Shutemov goto err_slab; 641ba76149fSAndrea Arcangeli 64265ebb64fSKirill A. Shutemov err = register_shrinker(&huge_zero_page_shrinker); 64365ebb64fSKirill A. Shutemov if (err) 64465ebb64fSKirill A. Shutemov goto err_hzp_shrinker; 64597ae1749SKirill A. Shutemov 64697562cd2SRik van Riel /* 64797562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 64897562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 64997562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 65097562cd2SRik van Riel */ 65179553da2SKirill A. Shutemov if (totalram_pages < (512 << (20 - PAGE_SHIFT))) { 65297562cd2SRik van Riel transparent_hugepage_flags = 0; 65379553da2SKirill A. Shutemov return 0; 65479553da2SKirill A. Shutemov } 65597562cd2SRik van Riel 65679553da2SKirill A. Shutemov err = start_stop_khugepaged(); 65765ebb64fSKirill A. Shutemov if (err) 65865ebb64fSKirill A. Shutemov goto err_khugepaged; 659ba76149fSAndrea Arcangeli 660569e5590SShaohua Li return 0; 66165ebb64fSKirill A. Shutemov err_khugepaged: 66265ebb64fSKirill A. Shutemov unregister_shrinker(&huge_zero_page_shrinker); 66365ebb64fSKirill A. Shutemov err_hzp_shrinker: 66465ebb64fSKirill A. Shutemov khugepaged_slab_exit(); 66565ebb64fSKirill A. Shutemov err_slab: 666569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 66765ebb64fSKirill A. Shutemov err_sysfs: 668ba76149fSAndrea Arcangeli return err; 66971e3aac0SAndrea Arcangeli } 670a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 67171e3aac0SAndrea Arcangeli 67271e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 67371e3aac0SAndrea Arcangeli { 67471e3aac0SAndrea Arcangeli int ret = 0; 67571e3aac0SAndrea Arcangeli if (!str) 67671e3aac0SAndrea Arcangeli goto out; 67771e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 67871e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 67971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 68071e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 68171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 68271e3aac0SAndrea Arcangeli ret = 1; 68371e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 68471e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 68571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 68671e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 68771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 68871e3aac0SAndrea Arcangeli ret = 1; 68971e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 69071e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 69171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 69271e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 69371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 69471e3aac0SAndrea Arcangeli ret = 1; 69571e3aac0SAndrea Arcangeli } 69671e3aac0SAndrea Arcangeli out: 69771e3aac0SAndrea Arcangeli if (!ret) 698ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 69971e3aac0SAndrea Arcangeli return ret; 70071e3aac0SAndrea Arcangeli } 70171e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 70271e3aac0SAndrea Arcangeli 703b32967ffSMel Gorman pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 70471e3aac0SAndrea Arcangeli { 70571e3aac0SAndrea Arcangeli if (likely(vma->vm_flags & VM_WRITE)) 70671e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 70771e3aac0SAndrea Arcangeli return pmd; 70871e3aac0SAndrea Arcangeli } 70971e3aac0SAndrea Arcangeli 7103122359aSKirill A. Shutemov static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot) 711b3092b3bSBob Liu { 712b3092b3bSBob Liu pmd_t entry; 7133122359aSKirill A. Shutemov entry = mk_pmd(page, prot); 714b3092b3bSBob Liu entry = pmd_mkhuge(entry); 715b3092b3bSBob Liu return entry; 716b3092b3bSBob Liu } 717b3092b3bSBob Liu 71871e3aac0SAndrea Arcangeli static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, 71971e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 72071e3aac0SAndrea Arcangeli unsigned long haddr, pmd_t *pmd, 721*6b251fc9SAndrea Arcangeli struct page *page, gfp_t gfp, 722*6b251fc9SAndrea Arcangeli unsigned int flags) 72371e3aac0SAndrea Arcangeli { 72400501b53SJohannes Weiner struct mem_cgroup *memcg; 72571e3aac0SAndrea Arcangeli pgtable_t pgtable; 726c4088ebdSKirill A. Shutemov spinlock_t *ptl; 72771e3aac0SAndrea Arcangeli 728309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 72900501b53SJohannes Weiner 730*6b251fc9SAndrea Arcangeli if (mem_cgroup_try_charge(page, mm, gfp, &memcg)) { 731*6b251fc9SAndrea Arcangeli put_page(page); 732*6b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 733*6b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 734*6b251fc9SAndrea Arcangeli } 73571e3aac0SAndrea Arcangeli 73600501b53SJohannes Weiner pgtable = pte_alloc_one(mm, haddr); 73700501b53SJohannes Weiner if (unlikely(!pgtable)) { 73800501b53SJohannes Weiner mem_cgroup_cancel_charge(page, memcg); 739*6b251fc9SAndrea Arcangeli put_page(page); 74000501b53SJohannes Weiner return VM_FAULT_OOM; 74100501b53SJohannes Weiner } 74200501b53SJohannes Weiner 74371e3aac0SAndrea Arcangeli clear_huge_page(page, haddr, HPAGE_PMD_NR); 74452f37629SMinchan Kim /* 74552f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 74652f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 74752f37629SMinchan Kim * write. 74852f37629SMinchan Kim */ 74971e3aac0SAndrea Arcangeli __SetPageUptodate(page); 75071e3aac0SAndrea Arcangeli 751c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 75271e3aac0SAndrea Arcangeli if (unlikely(!pmd_none(*pmd))) { 753c4088ebdSKirill A. Shutemov spin_unlock(ptl); 75400501b53SJohannes Weiner mem_cgroup_cancel_charge(page, memcg); 75571e3aac0SAndrea Arcangeli put_page(page); 75671e3aac0SAndrea Arcangeli pte_free(mm, pgtable); 75771e3aac0SAndrea Arcangeli } else { 75871e3aac0SAndrea Arcangeli pmd_t entry; 759*6b251fc9SAndrea Arcangeli 760*6b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 761*6b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 762*6b251fc9SAndrea Arcangeli int ret; 763*6b251fc9SAndrea Arcangeli 764*6b251fc9SAndrea Arcangeli spin_unlock(ptl); 765*6b251fc9SAndrea Arcangeli mem_cgroup_cancel_charge(page, memcg); 766*6b251fc9SAndrea Arcangeli put_page(page); 767*6b251fc9SAndrea Arcangeli pte_free(mm, pgtable); 768*6b251fc9SAndrea Arcangeli ret = handle_userfault(vma, haddr, flags, 769*6b251fc9SAndrea Arcangeli VM_UFFD_MISSING); 770*6b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 771*6b251fc9SAndrea Arcangeli return ret; 772*6b251fc9SAndrea Arcangeli } 773*6b251fc9SAndrea Arcangeli 7743122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 7753122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 77671e3aac0SAndrea Arcangeli page_add_new_anon_rmap(page, vma, haddr); 77700501b53SJohannes Weiner mem_cgroup_commit_charge(page, memcg, false); 77800501b53SJohannes Weiner lru_cache_add_active_or_unevictable(page, vma); 7796b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 78071e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 78171e3aac0SAndrea Arcangeli add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 782e1f56c89SKirill A. Shutemov atomic_long_inc(&mm->nr_ptes); 783c4088ebdSKirill A. Shutemov spin_unlock(ptl); 784*6b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 78571e3aac0SAndrea Arcangeli } 78671e3aac0SAndrea Arcangeli 787aa2e878eSDavid Rientjes return 0; 78871e3aac0SAndrea Arcangeli } 78971e3aac0SAndrea Arcangeli 790cc5d462fSAndi Kleen static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) 7910bbbc0b3SAndrea Arcangeli { 792cc5d462fSAndi Kleen return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; 7930bbbc0b3SAndrea Arcangeli } 7940bbbc0b3SAndrea Arcangeli 795c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 796*6b251fc9SAndrea Arcangeli static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 79797ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 7985918d10aSKirill A. Shutemov struct page *zero_page) 799fc9fe822SKirill A. Shutemov { 800fc9fe822SKirill A. Shutemov pmd_t entry; 8015918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 802fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 8036b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 804fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 805e1f56c89SKirill A. Shutemov atomic_long_inc(&mm->nr_ptes); 806fc9fe822SKirill A. Shutemov } 807fc9fe822SKirill A. Shutemov 80871e3aac0SAndrea Arcangeli int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 80971e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, 81071e3aac0SAndrea Arcangeli unsigned int flags) 81171e3aac0SAndrea Arcangeli { 812077fcf11SAneesh Kumar K.V gfp_t gfp; 81371e3aac0SAndrea Arcangeli struct page *page; 81471e3aac0SAndrea Arcangeli unsigned long haddr = address & HPAGE_PMD_MASK; 81571e3aac0SAndrea Arcangeli 816128ec037SKirill A. Shutemov if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) 817c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 81871e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 81971e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 8206d50e60cSDavid Rientjes if (unlikely(khugepaged_enter(vma, vma->vm_flags))) 821ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 822593befa6SDominik Dingel if (!(flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(mm) && 82379da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 824c4088ebdSKirill A. Shutemov spinlock_t *ptl; 82580371957SKirill A. Shutemov pgtable_t pgtable; 8265918d10aSKirill A. Shutemov struct page *zero_page; 8273ea41e62SKirill A. Shutemov bool set; 828*6b251fc9SAndrea Arcangeli int ret; 82980371957SKirill A. Shutemov pgtable = pte_alloc_one(mm, haddr); 83080371957SKirill A. Shutemov if (unlikely(!pgtable)) 83180371957SKirill A. Shutemov return VM_FAULT_OOM; 8325918d10aSKirill A. Shutemov zero_page = get_huge_zero_page(); 8335918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 83497ae1749SKirill A. Shutemov pte_free(mm, pgtable); 83597ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 836c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 83797ae1749SKirill A. Shutemov } 838c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 839*6b251fc9SAndrea Arcangeli ret = 0; 840*6b251fc9SAndrea Arcangeli set = false; 841*6b251fc9SAndrea Arcangeli if (pmd_none(*pmd)) { 842*6b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 843*6b251fc9SAndrea Arcangeli spin_unlock(ptl); 844*6b251fc9SAndrea Arcangeli ret = handle_userfault(vma, haddr, flags, 845*6b251fc9SAndrea Arcangeli VM_UFFD_MISSING); 846*6b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 847*6b251fc9SAndrea Arcangeli } else { 848*6b251fc9SAndrea Arcangeli set_huge_zero_page(pgtable, mm, vma, 849*6b251fc9SAndrea Arcangeli haddr, pmd, 8505918d10aSKirill A. Shutemov zero_page); 851c4088ebdSKirill A. Shutemov spin_unlock(ptl); 852*6b251fc9SAndrea Arcangeli set = true; 853*6b251fc9SAndrea Arcangeli } 854*6b251fc9SAndrea Arcangeli } else 855*6b251fc9SAndrea Arcangeli spin_unlock(ptl); 8563ea41e62SKirill A. Shutemov if (!set) { 8573ea41e62SKirill A. Shutemov pte_free(mm, pgtable); 8583ea41e62SKirill A. Shutemov put_huge_zero_page(); 8593ea41e62SKirill A. Shutemov } 860*6b251fc9SAndrea Arcangeli return ret; 86180371957SKirill A. Shutemov } 862077fcf11SAneesh Kumar K.V gfp = alloc_hugepage_gfpmask(transparent_hugepage_defrag(vma), 0); 863077fcf11SAneesh Kumar K.V page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); 86481ab4201SAndi Kleen if (unlikely(!page)) { 86581ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 866c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 86781ab4201SAndi Kleen } 868*6b251fc9SAndrea Arcangeli return __do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page, gfp, flags); 86971e3aac0SAndrea Arcangeli } 87071e3aac0SAndrea Arcangeli 87171e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 87271e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 87371e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 87471e3aac0SAndrea Arcangeli { 875c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 87671e3aac0SAndrea Arcangeli struct page *src_page; 87771e3aac0SAndrea Arcangeli pmd_t pmd; 87871e3aac0SAndrea Arcangeli pgtable_t pgtable; 87971e3aac0SAndrea Arcangeli int ret; 88071e3aac0SAndrea Arcangeli 88171e3aac0SAndrea Arcangeli ret = -ENOMEM; 88271e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(dst_mm, addr); 88371e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 88471e3aac0SAndrea Arcangeli goto out; 88571e3aac0SAndrea Arcangeli 886c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 887c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 888c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 88971e3aac0SAndrea Arcangeli 89071e3aac0SAndrea Arcangeli ret = -EAGAIN; 89171e3aac0SAndrea Arcangeli pmd = *src_pmd; 89271e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(pmd))) { 89371e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 89471e3aac0SAndrea Arcangeli goto out_unlock; 89571e3aac0SAndrea Arcangeli } 896fc9fe822SKirill A. Shutemov /* 897c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 898fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 899fc9fe822SKirill A. Shutemov * a page table. 900fc9fe822SKirill A. Shutemov */ 901fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 9025918d10aSKirill A. Shutemov struct page *zero_page; 90397ae1749SKirill A. Shutemov /* 90497ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 90597ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 90697ae1749SKirill A. Shutemov * reference. 90797ae1749SKirill A. Shutemov */ 9085918d10aSKirill A. Shutemov zero_page = get_huge_zero_page(); 909*6b251fc9SAndrea Arcangeli set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, 9105918d10aSKirill A. Shutemov zero_page); 911fc9fe822SKirill A. Shutemov ret = 0; 912fc9fe822SKirill A. Shutemov goto out_unlock; 913fc9fe822SKirill A. Shutemov } 914de466bd6SMel Gorman 91571e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_splitting(pmd))) { 91671e3aac0SAndrea Arcangeli /* split huge page running from under us */ 917c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 918c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 91971e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 92071e3aac0SAndrea Arcangeli 92171e3aac0SAndrea Arcangeli wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ 92271e3aac0SAndrea Arcangeli goto out; 92371e3aac0SAndrea Arcangeli } 92471e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 925309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 92671e3aac0SAndrea Arcangeli get_page(src_page); 92771e3aac0SAndrea Arcangeli page_dup_rmap(src_page); 92871e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 92971e3aac0SAndrea Arcangeli 93071e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 93171e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 9326b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 93371e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 934e1f56c89SKirill A. Shutemov atomic_long_inc(&dst_mm->nr_ptes); 93571e3aac0SAndrea Arcangeli 93671e3aac0SAndrea Arcangeli ret = 0; 93771e3aac0SAndrea Arcangeli out_unlock: 938c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 939c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 94071e3aac0SAndrea Arcangeli out: 94171e3aac0SAndrea Arcangeli return ret; 94271e3aac0SAndrea Arcangeli } 94371e3aac0SAndrea Arcangeli 944a1dd450bSWill Deacon void huge_pmd_set_accessed(struct mm_struct *mm, 945a1dd450bSWill Deacon struct vm_area_struct *vma, 946a1dd450bSWill Deacon unsigned long address, 947a1dd450bSWill Deacon pmd_t *pmd, pmd_t orig_pmd, 948a1dd450bSWill Deacon int dirty) 949a1dd450bSWill Deacon { 950c4088ebdSKirill A. Shutemov spinlock_t *ptl; 951a1dd450bSWill Deacon pmd_t entry; 952a1dd450bSWill Deacon unsigned long haddr; 953a1dd450bSWill Deacon 954c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 955a1dd450bSWill Deacon if (unlikely(!pmd_same(*pmd, orig_pmd))) 956a1dd450bSWill Deacon goto unlock; 957a1dd450bSWill Deacon 958a1dd450bSWill Deacon entry = pmd_mkyoung(orig_pmd); 959a1dd450bSWill Deacon haddr = address & HPAGE_PMD_MASK; 960a1dd450bSWill Deacon if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) 961a1dd450bSWill Deacon update_mmu_cache_pmd(vma, address, pmd); 962a1dd450bSWill Deacon 963a1dd450bSWill Deacon unlock: 964c4088ebdSKirill A. Shutemov spin_unlock(ptl); 965a1dd450bSWill Deacon } 966a1dd450bSWill Deacon 9675338a937SHugh Dickins /* 9685338a937SHugh Dickins * Save CONFIG_DEBUG_PAGEALLOC from faulting falsely on tail pages 9695338a937SHugh Dickins * during copy_user_huge_page()'s copy_page_rep(): in the case when 9705338a937SHugh Dickins * the source page gets split and a tail freed before copy completes. 9715338a937SHugh Dickins * Called under pmd_lock of checked pmd, so safe from splitting itself. 9725338a937SHugh Dickins */ 9735338a937SHugh Dickins static void get_user_huge_page(struct page *page) 9745338a937SHugh Dickins { 9755338a937SHugh Dickins if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) { 9765338a937SHugh Dickins struct page *endpage = page + HPAGE_PMD_NR; 9775338a937SHugh Dickins 9785338a937SHugh Dickins atomic_add(HPAGE_PMD_NR, &page->_count); 9795338a937SHugh Dickins while (++page < endpage) 9805338a937SHugh Dickins get_huge_page_tail(page); 9815338a937SHugh Dickins } else { 9825338a937SHugh Dickins get_page(page); 9835338a937SHugh Dickins } 9845338a937SHugh Dickins } 9855338a937SHugh Dickins 9865338a937SHugh Dickins static void put_user_huge_page(struct page *page) 9875338a937SHugh Dickins { 9885338a937SHugh Dickins if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) { 9895338a937SHugh Dickins struct page *endpage = page + HPAGE_PMD_NR; 9905338a937SHugh Dickins 9915338a937SHugh Dickins while (page < endpage) 9925338a937SHugh Dickins put_page(page++); 9935338a937SHugh Dickins } else { 9945338a937SHugh Dickins put_page(page); 9955338a937SHugh Dickins } 9965338a937SHugh Dickins } 9975338a937SHugh Dickins 99871e3aac0SAndrea Arcangeli static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, 99971e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 100071e3aac0SAndrea Arcangeli unsigned long address, 100171e3aac0SAndrea Arcangeli pmd_t *pmd, pmd_t orig_pmd, 100271e3aac0SAndrea Arcangeli struct page *page, 100371e3aac0SAndrea Arcangeli unsigned long haddr) 100471e3aac0SAndrea Arcangeli { 100500501b53SJohannes Weiner struct mem_cgroup *memcg; 1006c4088ebdSKirill A. Shutemov spinlock_t *ptl; 100771e3aac0SAndrea Arcangeli pgtable_t pgtable; 100871e3aac0SAndrea Arcangeli pmd_t _pmd; 100971e3aac0SAndrea Arcangeli int ret = 0, i; 101071e3aac0SAndrea Arcangeli struct page **pages; 10112ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 10122ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 101371e3aac0SAndrea Arcangeli 101471e3aac0SAndrea Arcangeli pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, 101571e3aac0SAndrea Arcangeli GFP_KERNEL); 101671e3aac0SAndrea Arcangeli if (unlikely(!pages)) { 101771e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 101871e3aac0SAndrea Arcangeli goto out; 101971e3aac0SAndrea Arcangeli } 102071e3aac0SAndrea Arcangeli 102171e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 1022cc5d462fSAndi Kleen pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | 1023cc5d462fSAndi Kleen __GFP_OTHER_NODE, 102419ee151eSAndi Kleen vma, address, page_to_nid(page)); 1025b9bbfbe3SAndrea Arcangeli if (unlikely(!pages[i] || 102600501b53SJohannes Weiner mem_cgroup_try_charge(pages[i], mm, GFP_KERNEL, 102700501b53SJohannes Weiner &memcg))) { 1028b9bbfbe3SAndrea Arcangeli if (pages[i]) 102971e3aac0SAndrea Arcangeli put_page(pages[i]); 1030b9bbfbe3SAndrea Arcangeli while (--i >= 0) { 103100501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 103200501b53SJohannes Weiner set_page_private(pages[i], 0); 103300501b53SJohannes Weiner mem_cgroup_cancel_charge(pages[i], memcg); 1034b9bbfbe3SAndrea Arcangeli put_page(pages[i]); 1035b9bbfbe3SAndrea Arcangeli } 103671e3aac0SAndrea Arcangeli kfree(pages); 103771e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 103871e3aac0SAndrea Arcangeli goto out; 103971e3aac0SAndrea Arcangeli } 104000501b53SJohannes Weiner set_page_private(pages[i], (unsigned long)memcg); 104171e3aac0SAndrea Arcangeli } 104271e3aac0SAndrea Arcangeli 104371e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 104471e3aac0SAndrea Arcangeli copy_user_highpage(pages[i], page + i, 10450089e485SHillf Danton haddr + PAGE_SIZE * i, vma); 104671e3aac0SAndrea Arcangeli __SetPageUptodate(pages[i]); 104771e3aac0SAndrea Arcangeli cond_resched(); 104871e3aac0SAndrea Arcangeli } 104971e3aac0SAndrea Arcangeli 10502ec74c3eSSagi Grimberg mmun_start = haddr; 10512ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 10522ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 10532ec74c3eSSagi Grimberg 1054c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 105571e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 105671e3aac0SAndrea Arcangeli goto out_free_pages; 1057309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 105871e3aac0SAndrea Arcangeli 10598809aa2dSAneesh Kumar K.V pmdp_huge_clear_flush_notify(vma, haddr, pmd); 106071e3aac0SAndrea Arcangeli /* leave pmd empty until pte is filled */ 106171e3aac0SAndrea Arcangeli 10626b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 106371e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 106471e3aac0SAndrea Arcangeli 106571e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 106671e3aac0SAndrea Arcangeli pte_t *pte, entry; 106771e3aac0SAndrea Arcangeli entry = mk_pte(pages[i], vma->vm_page_prot); 106871e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 106900501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 107000501b53SJohannes Weiner set_page_private(pages[i], 0); 107171e3aac0SAndrea Arcangeli page_add_new_anon_rmap(pages[i], vma, haddr); 107200501b53SJohannes Weiner mem_cgroup_commit_charge(pages[i], memcg, false); 107300501b53SJohannes Weiner lru_cache_add_active_or_unevictable(pages[i], vma); 107471e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 107571e3aac0SAndrea Arcangeli VM_BUG_ON(!pte_none(*pte)); 107671e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 107771e3aac0SAndrea Arcangeli pte_unmap(pte); 107871e3aac0SAndrea Arcangeli } 107971e3aac0SAndrea Arcangeli kfree(pages); 108071e3aac0SAndrea Arcangeli 108171e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 108271e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 108371e3aac0SAndrea Arcangeli page_remove_rmap(page); 1084c4088ebdSKirill A. Shutemov spin_unlock(ptl); 108571e3aac0SAndrea Arcangeli 10862ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 10872ec74c3eSSagi Grimberg 108871e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 108971e3aac0SAndrea Arcangeli put_page(page); 109071e3aac0SAndrea Arcangeli 109171e3aac0SAndrea Arcangeli out: 109271e3aac0SAndrea Arcangeli return ret; 109371e3aac0SAndrea Arcangeli 109471e3aac0SAndrea Arcangeli out_free_pages: 1095c4088ebdSKirill A. Shutemov spin_unlock(ptl); 10962ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 1097b9bbfbe3SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 109800501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 109900501b53SJohannes Weiner set_page_private(pages[i], 0); 110000501b53SJohannes Weiner mem_cgroup_cancel_charge(pages[i], memcg); 110171e3aac0SAndrea Arcangeli put_page(pages[i]); 1102b9bbfbe3SAndrea Arcangeli } 110371e3aac0SAndrea Arcangeli kfree(pages); 110471e3aac0SAndrea Arcangeli goto out; 110571e3aac0SAndrea Arcangeli } 110671e3aac0SAndrea Arcangeli 110771e3aac0SAndrea Arcangeli int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 110871e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, pmd_t orig_pmd) 110971e3aac0SAndrea Arcangeli { 1110c4088ebdSKirill A. Shutemov spinlock_t *ptl; 111171e3aac0SAndrea Arcangeli int ret = 0; 111293b4796dSKirill A. Shutemov struct page *page = NULL, *new_page; 111300501b53SJohannes Weiner struct mem_cgroup *memcg; 111471e3aac0SAndrea Arcangeli unsigned long haddr; 11152ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 11162ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 11173b363692SMichal Hocko gfp_t huge_gfp; /* for allocation and charge */ 111871e3aac0SAndrea Arcangeli 1119c4088ebdSKirill A. Shutemov ptl = pmd_lockptr(mm, pmd); 112081d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 112193b4796dSKirill A. Shutemov haddr = address & HPAGE_PMD_MASK; 112293b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 112393b4796dSKirill A. Shutemov goto alloc; 1124c4088ebdSKirill A. Shutemov spin_lock(ptl); 112571e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 112671e3aac0SAndrea Arcangeli goto out_unlock; 112771e3aac0SAndrea Arcangeli 112871e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 1129309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); 113071e3aac0SAndrea Arcangeli if (page_mapcount(page) == 1) { 113171e3aac0SAndrea Arcangeli pmd_t entry; 113271e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 113371e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 113471e3aac0SAndrea Arcangeli if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) 1135b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 113671e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 113771e3aac0SAndrea Arcangeli goto out_unlock; 113871e3aac0SAndrea Arcangeli } 11395338a937SHugh Dickins get_user_huge_page(page); 1140c4088ebdSKirill A. Shutemov spin_unlock(ptl); 114193b4796dSKirill A. Shutemov alloc: 114271e3aac0SAndrea Arcangeli if (transparent_hugepage_enabled(vma) && 1143077fcf11SAneesh Kumar K.V !transparent_hugepage_debug_cow()) { 11443b363692SMichal Hocko huge_gfp = alloc_hugepage_gfpmask(transparent_hugepage_defrag(vma), 0); 11453b363692SMichal Hocko new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); 1146077fcf11SAneesh Kumar K.V } else 114771e3aac0SAndrea Arcangeli new_page = NULL; 114871e3aac0SAndrea Arcangeli 114971e3aac0SAndrea Arcangeli if (unlikely(!new_page)) { 1150eecc1e42SHugh Dickins if (!page) { 1151e9b71ca9SKirill A. Shutemov split_huge_page_pmd(vma, address, pmd); 1152e9b71ca9SKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 115393b4796dSKirill A. Shutemov } else { 115471e3aac0SAndrea Arcangeli ret = do_huge_pmd_wp_page_fallback(mm, vma, address, 115571e3aac0SAndrea Arcangeli pmd, orig_pmd, page, haddr); 11569845cbbdSKirill A. Shutemov if (ret & VM_FAULT_OOM) { 11571f1d06c3SDavid Rientjes split_huge_page(page); 11589845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 11599845cbbdSKirill A. Shutemov } 11605338a937SHugh Dickins put_user_huge_page(page); 116193b4796dSKirill A. Shutemov } 116217766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 116371e3aac0SAndrea Arcangeli goto out; 116471e3aac0SAndrea Arcangeli } 116571e3aac0SAndrea Arcangeli 11663b363692SMichal Hocko if (unlikely(mem_cgroup_try_charge(new_page, mm, huge_gfp, &memcg))) { 1167b9bbfbe3SAndrea Arcangeli put_page(new_page); 116893b4796dSKirill A. Shutemov if (page) { 11691f1d06c3SDavid Rientjes split_huge_page(page); 11705338a937SHugh Dickins put_user_huge_page(page); 11719845cbbdSKirill A. Shutemov } else 11729845cbbdSKirill A. Shutemov split_huge_page_pmd(vma, address, pmd); 11739845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 117417766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 1175b9bbfbe3SAndrea Arcangeli goto out; 1176b9bbfbe3SAndrea Arcangeli } 1177b9bbfbe3SAndrea Arcangeli 117817766ddeSDavid Rientjes count_vm_event(THP_FAULT_ALLOC); 117917766ddeSDavid Rientjes 1180eecc1e42SHugh Dickins if (!page) 118193b4796dSKirill A. Shutemov clear_huge_page(new_page, haddr, HPAGE_PMD_NR); 118293b4796dSKirill A. Shutemov else 118371e3aac0SAndrea Arcangeli copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); 118471e3aac0SAndrea Arcangeli __SetPageUptodate(new_page); 118571e3aac0SAndrea Arcangeli 11862ec74c3eSSagi Grimberg mmun_start = haddr; 11872ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 11882ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 11892ec74c3eSSagi Grimberg 1190c4088ebdSKirill A. Shutemov spin_lock(ptl); 119193b4796dSKirill A. Shutemov if (page) 11925338a937SHugh Dickins put_user_huge_page(page); 1193b9bbfbe3SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) { 1194c4088ebdSKirill A. Shutemov spin_unlock(ptl); 119500501b53SJohannes Weiner mem_cgroup_cancel_charge(new_page, memcg); 119671e3aac0SAndrea Arcangeli put_page(new_page); 11972ec74c3eSSagi Grimberg goto out_mn; 1198b9bbfbe3SAndrea Arcangeli } else { 119971e3aac0SAndrea Arcangeli pmd_t entry; 12003122359aSKirill A. Shutemov entry = mk_huge_pmd(new_page, vma->vm_page_prot); 12013122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 12028809aa2dSAneesh Kumar K.V pmdp_huge_clear_flush_notify(vma, haddr, pmd); 120371e3aac0SAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, haddr); 120400501b53SJohannes Weiner mem_cgroup_commit_charge(new_page, memcg, false); 120500501b53SJohannes Weiner lru_cache_add_active_or_unevictable(new_page, vma); 120671e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 1207b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 1208eecc1e42SHugh Dickins if (!page) { 120993b4796dSKirill A. Shutemov add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 121097ae1749SKirill A. Shutemov put_huge_zero_page(); 121197ae1749SKirill A. Shutemov } else { 1212309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 121371e3aac0SAndrea Arcangeli page_remove_rmap(page); 121471e3aac0SAndrea Arcangeli put_page(page); 121593b4796dSKirill A. Shutemov } 121671e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 121771e3aac0SAndrea Arcangeli } 1218c4088ebdSKirill A. Shutemov spin_unlock(ptl); 12192ec74c3eSSagi Grimberg out_mn: 12202ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 12212ec74c3eSSagi Grimberg out: 12222ec74c3eSSagi Grimberg return ret; 122371e3aac0SAndrea Arcangeli out_unlock: 1224c4088ebdSKirill A. Shutemov spin_unlock(ptl); 122571e3aac0SAndrea Arcangeli return ret; 122671e3aac0SAndrea Arcangeli } 122771e3aac0SAndrea Arcangeli 1228b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 122971e3aac0SAndrea Arcangeli unsigned long addr, 123071e3aac0SAndrea Arcangeli pmd_t *pmd, 123171e3aac0SAndrea Arcangeli unsigned int flags) 123271e3aac0SAndrea Arcangeli { 1233b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 123471e3aac0SAndrea Arcangeli struct page *page = NULL; 123571e3aac0SAndrea Arcangeli 1236c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 123771e3aac0SAndrea Arcangeli 123871e3aac0SAndrea Arcangeli if (flags & FOLL_WRITE && !pmd_write(*pmd)) 123971e3aac0SAndrea Arcangeli goto out; 124071e3aac0SAndrea Arcangeli 124185facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 124285facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 124385facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 124485facf25SKirill A. Shutemov 12452b4847e7SMel Gorman /* Full NUMA hinting faults to serialise migration in fault paths */ 12468a0516edSMel Gorman if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) 12472b4847e7SMel Gorman goto out; 12482b4847e7SMel Gorman 124971e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 1250309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 125171e3aac0SAndrea Arcangeli if (flags & FOLL_TOUCH) { 125271e3aac0SAndrea Arcangeli pmd_t _pmd; 125371e3aac0SAndrea Arcangeli /* 125471e3aac0SAndrea Arcangeli * We should set the dirty bit only for FOLL_WRITE but 125571e3aac0SAndrea Arcangeli * for now the dirty bit in the pmd is meaningless. 125671e3aac0SAndrea Arcangeli * And if the dirty bit will become meaningful and 125771e3aac0SAndrea Arcangeli * we'll only set it with FOLL_WRITE, an atomic 125871e3aac0SAndrea Arcangeli * set_bit will be required on the pmd to set the 125971e3aac0SAndrea Arcangeli * young bit, instead of the current set_pmd_at. 126071e3aac0SAndrea Arcangeli */ 126171e3aac0SAndrea Arcangeli _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); 12628663890aSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 12638663890aSAneesh Kumar K.V pmd, _pmd, 1)) 12648663890aSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 126571e3aac0SAndrea Arcangeli } 126684d33df2SKirill A. Shutemov if ((flags & FOLL_POPULATE) && (vma->vm_flags & VM_LOCKED)) { 1267b676b293SDavid Rientjes if (page->mapping && trylock_page(page)) { 1268b676b293SDavid Rientjes lru_add_drain(); 1269b676b293SDavid Rientjes if (page->mapping) 1270b676b293SDavid Rientjes mlock_vma_page(page); 1271b676b293SDavid Rientjes unlock_page(page); 1272b676b293SDavid Rientjes } 1273b676b293SDavid Rientjes } 127471e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1275309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 127671e3aac0SAndrea Arcangeli if (flags & FOLL_GET) 127770b50f94SAndrea Arcangeli get_page_foll(page); 127871e3aac0SAndrea Arcangeli 127971e3aac0SAndrea Arcangeli out: 128071e3aac0SAndrea Arcangeli return page; 128171e3aac0SAndrea Arcangeli } 128271e3aac0SAndrea Arcangeli 1283d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 12844daae3b4SMel Gorman int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, 12854daae3b4SMel Gorman unsigned long addr, pmd_t pmd, pmd_t *pmdp) 1286d10e63f2SMel Gorman { 1287c4088ebdSKirill A. Shutemov spinlock_t *ptl; 1288b8916634SMel Gorman struct anon_vma *anon_vma = NULL; 1289b32967ffSMel Gorman struct page *page; 1290d10e63f2SMel Gorman unsigned long haddr = addr & HPAGE_PMD_MASK; 12918191acbdSMel Gorman int page_nid = -1, this_nid = numa_node_id(); 129290572890SPeter Zijlstra int target_nid, last_cpupid = -1; 12938191acbdSMel Gorman bool page_locked; 12948191acbdSMel Gorman bool migrated = false; 1295b191f9b1SMel Gorman bool was_writable; 12966688cc05SPeter Zijlstra int flags = 0; 1297d10e63f2SMel Gorman 1298c0e7cad9SMel Gorman /* A PROT_NONE fault should not end up here */ 1299c0e7cad9SMel Gorman BUG_ON(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))); 1300c0e7cad9SMel Gorman 1301c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmdp); 1302d10e63f2SMel Gorman if (unlikely(!pmd_same(pmd, *pmdp))) 1303d10e63f2SMel Gorman goto out_unlock; 1304d10e63f2SMel Gorman 1305de466bd6SMel Gorman /* 1306de466bd6SMel Gorman * If there are potential migrations, wait for completion and retry 1307de466bd6SMel Gorman * without disrupting NUMA hinting information. Do not relock and 1308de466bd6SMel Gorman * check_same as the page may no longer be mapped. 1309de466bd6SMel Gorman */ 1310de466bd6SMel Gorman if (unlikely(pmd_trans_migrating(*pmdp))) { 13115d833062SMel Gorman page = pmd_page(*pmdp); 1312de466bd6SMel Gorman spin_unlock(ptl); 13135d833062SMel Gorman wait_on_page_locked(page); 1314de466bd6SMel Gorman goto out; 1315de466bd6SMel Gorman } 1316de466bd6SMel Gorman 1317d10e63f2SMel Gorman page = pmd_page(pmd); 1318a1a46184SMel Gorman BUG_ON(is_huge_zero_page(page)); 13198191acbdSMel Gorman page_nid = page_to_nid(page); 132090572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 132103c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 132204bb2f94SRik van Riel if (page_nid == this_nid) { 132303c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 132404bb2f94SRik van Riel flags |= TNF_FAULT_LOCAL; 132504bb2f94SRik van Riel } 13264daae3b4SMel Gorman 1327bea66fbdSMel Gorman /* See similar comment in do_numa_page for explanation */ 1328bea66fbdSMel Gorman if (!(vma->vm_flags & VM_WRITE)) 13296688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 13306688cc05SPeter Zijlstra 13316688cc05SPeter Zijlstra /* 1332ff9042b1SMel Gorman * Acquire the page lock to serialise THP migrations but avoid dropping 1333ff9042b1SMel Gorman * page_table_lock if at all possible 1334ff9042b1SMel Gorman */ 1335b8916634SMel Gorman page_locked = trylock_page(page); 1336b8916634SMel Gorman target_nid = mpol_misplaced(page, vma, haddr); 1337b8916634SMel Gorman if (target_nid == -1) { 1338b8916634SMel Gorman /* If the page was locked, there are no parallel migrations */ 1339a54a407fSMel Gorman if (page_locked) 1340b8916634SMel Gorman goto clear_pmdnuma; 13412b4847e7SMel Gorman } 1342cbee9f88SPeter Zijlstra 1343de466bd6SMel Gorman /* Migration could have started since the pmd_trans_migrating check */ 13442b4847e7SMel Gorman if (!page_locked) { 1345c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1346b8916634SMel Gorman wait_on_page_locked(page); 1347a54a407fSMel Gorman page_nid = -1; 1348b8916634SMel Gorman goto out; 1349b8916634SMel Gorman } 1350b8916634SMel Gorman 13512b4847e7SMel Gorman /* 13522b4847e7SMel Gorman * Page is misplaced. Page lock serialises migrations. Acquire anon_vma 13532b4847e7SMel Gorman * to serialises splits 13542b4847e7SMel Gorman */ 1355b8916634SMel Gorman get_page(page); 1356c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1357b8916634SMel Gorman anon_vma = page_lock_anon_vma_read(page); 1358b32967ffSMel Gorman 1359c69307d5SPeter Zijlstra /* Confirm the PMD did not change while page_table_lock was released */ 1360c4088ebdSKirill A. Shutemov spin_lock(ptl); 1361b32967ffSMel Gorman if (unlikely(!pmd_same(pmd, *pmdp))) { 1362b32967ffSMel Gorman unlock_page(page); 1363b32967ffSMel Gorman put_page(page); 1364a54a407fSMel Gorman page_nid = -1; 1365b32967ffSMel Gorman goto out_unlock; 1366b32967ffSMel Gorman } 1367ff9042b1SMel Gorman 1368c3a489caSMel Gorman /* Bail if we fail to protect against THP splits for any reason */ 1369c3a489caSMel Gorman if (unlikely(!anon_vma)) { 1370c3a489caSMel Gorman put_page(page); 1371c3a489caSMel Gorman page_nid = -1; 1372c3a489caSMel Gorman goto clear_pmdnuma; 1373c3a489caSMel Gorman } 1374c3a489caSMel Gorman 1375a54a407fSMel Gorman /* 1376a54a407fSMel Gorman * Migrate the THP to the requested node, returns with page unlocked 13778a0516edSMel Gorman * and access rights restored. 1378a54a407fSMel Gorman */ 1379c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1380b32967ffSMel Gorman migrated = migrate_misplaced_transhuge_page(mm, vma, 1381340ef390SHugh Dickins pmdp, pmd, addr, page, target_nid); 13826688cc05SPeter Zijlstra if (migrated) { 13836688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 13848191acbdSMel Gorman page_nid = target_nid; 1385074c2381SMel Gorman } else 1386074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1387b32967ffSMel Gorman 13888191acbdSMel Gorman goto out; 13894daae3b4SMel Gorman clear_pmdnuma: 1390a54a407fSMel Gorman BUG_ON(!PageLocked(page)); 1391b191f9b1SMel Gorman was_writable = pmd_write(pmd); 13924d942466SMel Gorman pmd = pmd_modify(pmd, vma->vm_page_prot); 1393b7b04004SMel Gorman pmd = pmd_mkyoung(pmd); 1394b191f9b1SMel Gorman if (was_writable) 1395b191f9b1SMel Gorman pmd = pmd_mkwrite(pmd); 1396d10e63f2SMel Gorman set_pmd_at(mm, haddr, pmdp, pmd); 1397d10e63f2SMel Gorman update_mmu_cache_pmd(vma, addr, pmdp); 1398a54a407fSMel Gorman unlock_page(page); 1399d10e63f2SMel Gorman out_unlock: 1400c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1401b8916634SMel Gorman 1402b8916634SMel Gorman out: 1403b8916634SMel Gorman if (anon_vma) 1404b8916634SMel Gorman page_unlock_anon_vma_read(anon_vma); 1405b8916634SMel Gorman 14068191acbdSMel Gorman if (page_nid != -1) 14076688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags); 14088191acbdSMel Gorman 1409d10e63f2SMel Gorman return 0; 1410d10e63f2SMel Gorman } 1411d10e63f2SMel Gorman 141271e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1413f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 141471e3aac0SAndrea Arcangeli { 1415bf929152SKirill A. Shutemov spinlock_t *ptl; 141671e3aac0SAndrea Arcangeli int ret = 0; 141771e3aac0SAndrea Arcangeli 1418bf929152SKirill A. Shutemov if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { 141971e3aac0SAndrea Arcangeli struct page *page; 142071e3aac0SAndrea Arcangeli pgtable_t pgtable; 1421f5c8ad47SDavid Miller pmd_t orig_pmd; 1422a6bf2bb0SAneesh Kumar K.V /* 1423a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 14248809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1425a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1426a6bf2bb0SAneesh Kumar K.V * operations. 1427a6bf2bb0SAneesh Kumar K.V */ 14288809aa2dSAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, 1429fcbe08d6SMartin Schwidefsky tlb->fullmm); 1430f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1431a6bf2bb0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); 1432479f0abbSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) { 1433e1f56c89SKirill A. Shutemov atomic_long_dec(&tlb->mm->nr_ptes); 1434bf929152SKirill A. Shutemov spin_unlock(ptl); 143597ae1749SKirill A. Shutemov put_huge_zero_page(); 1436479f0abbSKirill A. Shutemov } else { 1437479f0abbSKirill A. Shutemov page = pmd_page(orig_pmd); 143871e3aac0SAndrea Arcangeli page_remove_rmap(page); 1439309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 144071e3aac0SAndrea Arcangeli add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1441309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1442e1f56c89SKirill A. Shutemov atomic_long_dec(&tlb->mm->nr_ptes); 1443bf929152SKirill A. Shutemov spin_unlock(ptl); 144471e3aac0SAndrea Arcangeli tlb_remove_page(tlb, page); 1445479f0abbSKirill A. Shutemov } 144671e3aac0SAndrea Arcangeli pte_free(tlb->mm, pgtable); 144771e3aac0SAndrea Arcangeli ret = 1; 144871e3aac0SAndrea Arcangeli } 144971e3aac0SAndrea Arcangeli return ret; 145071e3aac0SAndrea Arcangeli } 145171e3aac0SAndrea Arcangeli 145237a1c49aSAndrea Arcangeli int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, 145337a1c49aSAndrea Arcangeli unsigned long old_addr, 145437a1c49aSAndrea Arcangeli unsigned long new_addr, unsigned long old_end, 145537a1c49aSAndrea Arcangeli pmd_t *old_pmd, pmd_t *new_pmd) 145637a1c49aSAndrea Arcangeli { 1457bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 145837a1c49aSAndrea Arcangeli int ret = 0; 145937a1c49aSAndrea Arcangeli pmd_t pmd; 146037a1c49aSAndrea Arcangeli 146137a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 146237a1c49aSAndrea Arcangeli 146337a1c49aSAndrea Arcangeli if ((old_addr & ~HPAGE_PMD_MASK) || 146437a1c49aSAndrea Arcangeli (new_addr & ~HPAGE_PMD_MASK) || 146537a1c49aSAndrea Arcangeli old_end - old_addr < HPAGE_PMD_SIZE || 146637a1c49aSAndrea Arcangeli (new_vma->vm_flags & VM_NOHUGEPAGE)) 146737a1c49aSAndrea Arcangeli goto out; 146837a1c49aSAndrea Arcangeli 146937a1c49aSAndrea Arcangeli /* 147037a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 147137a1c49aSAndrea Arcangeli * should have release it. 147237a1c49aSAndrea Arcangeli */ 147337a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 147437a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 147537a1c49aSAndrea Arcangeli goto out; 147637a1c49aSAndrea Arcangeli } 147737a1c49aSAndrea Arcangeli 1478bf929152SKirill A. Shutemov /* 1479bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1480bf929152SKirill A. Shutemov * ptlocks because exclusive mmap_sem prevents deadlock. 1481bf929152SKirill A. Shutemov */ 1482bf929152SKirill A. Shutemov ret = __pmd_trans_huge_lock(old_pmd, vma, &old_ptl); 1483025c5b24SNaoya Horiguchi if (ret == 1) { 1484bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1485bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1486bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 14878809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 148837a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 14893592806cSKirill A. Shutemov 1490b3084f4dSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl)) { 1491b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 14923592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 14933592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 14943592806cSKirill A. Shutemov } 1495b3084f4dSAneesh Kumar K.V set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); 1496b3084f4dSAneesh Kumar K.V if (new_ptl != old_ptl) 1497b3084f4dSAneesh Kumar K.V spin_unlock(new_ptl); 1498bf929152SKirill A. Shutemov spin_unlock(old_ptl); 149937a1c49aSAndrea Arcangeli } 150037a1c49aSAndrea Arcangeli out: 150137a1c49aSAndrea Arcangeli return ret; 150237a1c49aSAndrea Arcangeli } 150337a1c49aSAndrea Arcangeli 1504f123d74aSMel Gorman /* 1505f123d74aSMel Gorman * Returns 1506f123d74aSMel Gorman * - 0 if PMD could not be locked 1507f123d74aSMel Gorman * - 1 if PMD was locked but protections unchange and TLB flush unnecessary 1508f123d74aSMel Gorman * - HPAGE_PMD_NR is protections changed and TLB flush necessary 1509f123d74aSMel Gorman */ 1510cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 1511e944fd67SMel Gorman unsigned long addr, pgprot_t newprot, int prot_numa) 1512cd7548abSJohannes Weiner { 1513cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1514bf929152SKirill A. Shutemov spinlock_t *ptl; 1515cd7548abSJohannes Weiner int ret = 0; 1516cd7548abSJohannes Weiner 1517bf929152SKirill A. Shutemov if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { 1518cd7548abSJohannes Weiner pmd_t entry; 1519b191f9b1SMel Gorman bool preserve_write = prot_numa && pmd_write(*pmd); 1520ba68bc01SMel Gorman ret = 1; 1521e944fd67SMel Gorman 1522e944fd67SMel Gorman /* 1523e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1524e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1525e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1526e944fd67SMel Gorman */ 1527e944fd67SMel Gorman if (prot_numa && is_huge_zero_pmd(*pmd)) { 1528e944fd67SMel Gorman spin_unlock(ptl); 1529ba68bc01SMel Gorman return ret; 1530e944fd67SMel Gorman } 1531e944fd67SMel Gorman 153210c1045fSMel Gorman if (!prot_numa || !pmd_protnone(*pmd)) { 15338809aa2dSAneesh Kumar K.V entry = pmdp_huge_get_and_clear_notify(mm, addr, pmd); 1534cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 1535b191f9b1SMel Gorman if (preserve_write) 1536b191f9b1SMel Gorman entry = pmd_mkwrite(entry); 1537f123d74aSMel Gorman ret = HPAGE_PMD_NR; 153856eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 1539b191f9b1SMel Gorman BUG_ON(!preserve_write && pmd_write(entry)); 154010c1045fSMel Gorman } 1541bf929152SKirill A. Shutemov spin_unlock(ptl); 1542cd7548abSJohannes Weiner } 1543cd7548abSJohannes Weiner 1544cd7548abSJohannes Weiner return ret; 1545cd7548abSJohannes Weiner } 1546cd7548abSJohannes Weiner 1547025c5b24SNaoya Horiguchi /* 1548025c5b24SNaoya Horiguchi * Returns 1 if a given pmd maps a stable (not under splitting) thp. 1549025c5b24SNaoya Horiguchi * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. 1550025c5b24SNaoya Horiguchi * 1551025c5b24SNaoya Horiguchi * Note that if it returns 1, this routine returns without unlocking page 1552025c5b24SNaoya Horiguchi * table locks. So callers must unlock them. 1553025c5b24SNaoya Horiguchi */ 1554bf929152SKirill A. Shutemov int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, 1555bf929152SKirill A. Shutemov spinlock_t **ptl) 1556025c5b24SNaoya Horiguchi { 1557bf929152SKirill A. Shutemov *ptl = pmd_lock(vma->vm_mm, pmd); 1558025c5b24SNaoya Horiguchi if (likely(pmd_trans_huge(*pmd))) { 1559025c5b24SNaoya Horiguchi if (unlikely(pmd_trans_splitting(*pmd))) { 1560bf929152SKirill A. Shutemov spin_unlock(*ptl); 1561025c5b24SNaoya Horiguchi wait_split_huge_page(vma->anon_vma, pmd); 1562025c5b24SNaoya Horiguchi return -1; 1563025c5b24SNaoya Horiguchi } else { 1564025c5b24SNaoya Horiguchi /* Thp mapped by 'pmd' is stable, so we can 1565025c5b24SNaoya Horiguchi * handle it as it is. */ 1566025c5b24SNaoya Horiguchi return 1; 1567025c5b24SNaoya Horiguchi } 1568025c5b24SNaoya Horiguchi } 1569bf929152SKirill A. Shutemov spin_unlock(*ptl); 1570025c5b24SNaoya Horiguchi return 0; 1571025c5b24SNaoya Horiguchi } 1572025c5b24SNaoya Horiguchi 1573117b0791SKirill A. Shutemov /* 1574117b0791SKirill A. Shutemov * This function returns whether a given @page is mapped onto the @address 1575117b0791SKirill A. Shutemov * in the virtual space of @mm. 1576117b0791SKirill A. Shutemov * 1577117b0791SKirill A. Shutemov * When it's true, this function returns *pmd with holding the page table lock 1578117b0791SKirill A. Shutemov * and passing it back to the caller via @ptl. 1579117b0791SKirill A. Shutemov * If it's false, returns NULL without holding the page table lock. 1580117b0791SKirill A. Shutemov */ 158171e3aac0SAndrea Arcangeli pmd_t *page_check_address_pmd(struct page *page, 158271e3aac0SAndrea Arcangeli struct mm_struct *mm, 158371e3aac0SAndrea Arcangeli unsigned long address, 1584117b0791SKirill A. Shutemov enum page_check_address_pmd_flag flag, 1585117b0791SKirill A. Shutemov spinlock_t **ptl) 158671e3aac0SAndrea Arcangeli { 1587b5a8cad3SKirill A. Shutemov pgd_t *pgd; 1588b5a8cad3SKirill A. Shutemov pud_t *pud; 1589117b0791SKirill A. Shutemov pmd_t *pmd; 159071e3aac0SAndrea Arcangeli 159171e3aac0SAndrea Arcangeli if (address & ~HPAGE_PMD_MASK) 1592117b0791SKirill A. Shutemov return NULL; 159371e3aac0SAndrea Arcangeli 1594b5a8cad3SKirill A. Shutemov pgd = pgd_offset(mm, address); 1595b5a8cad3SKirill A. Shutemov if (!pgd_present(*pgd)) 1596117b0791SKirill A. Shutemov return NULL; 1597b5a8cad3SKirill A. Shutemov pud = pud_offset(pgd, address); 1598b5a8cad3SKirill A. Shutemov if (!pud_present(*pud)) 1599b5a8cad3SKirill A. Shutemov return NULL; 1600b5a8cad3SKirill A. Shutemov pmd = pmd_offset(pud, address); 1601b5a8cad3SKirill A. Shutemov 1602117b0791SKirill A. Shutemov *ptl = pmd_lock(mm, pmd); 1603b5a8cad3SKirill A. Shutemov if (!pmd_present(*pmd)) 1604117b0791SKirill A. Shutemov goto unlock; 160571e3aac0SAndrea Arcangeli if (pmd_page(*pmd) != page) 1606117b0791SKirill A. Shutemov goto unlock; 160794fcc585SAndrea Arcangeli /* 160894fcc585SAndrea Arcangeli * split_vma() may create temporary aliased mappings. There is 160994fcc585SAndrea Arcangeli * no risk as long as all huge pmd are found and have their 161094fcc585SAndrea Arcangeli * splitting bit set before __split_huge_page_refcount 161194fcc585SAndrea Arcangeli * runs. Finding the same huge pmd more than once during the 161294fcc585SAndrea Arcangeli * same rmap walk is not a problem. 161394fcc585SAndrea Arcangeli */ 161494fcc585SAndrea Arcangeli if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && 161594fcc585SAndrea Arcangeli pmd_trans_splitting(*pmd)) 1616117b0791SKirill A. Shutemov goto unlock; 161771e3aac0SAndrea Arcangeli if (pmd_trans_huge(*pmd)) { 161871e3aac0SAndrea Arcangeli VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && 161971e3aac0SAndrea Arcangeli !pmd_trans_splitting(*pmd)); 1620117b0791SKirill A. Shutemov return pmd; 162171e3aac0SAndrea Arcangeli } 1622117b0791SKirill A. Shutemov unlock: 1623117b0791SKirill A. Shutemov spin_unlock(*ptl); 1624117b0791SKirill A. Shutemov return NULL; 162571e3aac0SAndrea Arcangeli } 162671e3aac0SAndrea Arcangeli 162771e3aac0SAndrea Arcangeli static int __split_huge_page_splitting(struct page *page, 162871e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 162971e3aac0SAndrea Arcangeli unsigned long address) 163071e3aac0SAndrea Arcangeli { 163171e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 1632117b0791SKirill A. Shutemov spinlock_t *ptl; 163371e3aac0SAndrea Arcangeli pmd_t *pmd; 163471e3aac0SAndrea Arcangeli int ret = 0; 16352ec74c3eSSagi Grimberg /* For mmu_notifiers */ 16362ec74c3eSSagi Grimberg const unsigned long mmun_start = address; 16372ec74c3eSSagi Grimberg const unsigned long mmun_end = address + HPAGE_PMD_SIZE; 163871e3aac0SAndrea Arcangeli 16392ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 164071e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 1641117b0791SKirill A. Shutemov PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG, &ptl); 164271e3aac0SAndrea Arcangeli if (pmd) { 164371e3aac0SAndrea Arcangeli /* 164471e3aac0SAndrea Arcangeli * We can't temporarily set the pmd to null in order 164571e3aac0SAndrea Arcangeli * to split it, the pmd must remain marked huge at all 164671e3aac0SAndrea Arcangeli * times or the VM won't take the pmd_trans_huge paths 16475a505085SIngo Molnar * and it won't wait on the anon_vma->root->rwsem to 164871e3aac0SAndrea Arcangeli * serialize against split_huge_page*. 164971e3aac0SAndrea Arcangeli */ 16502ec74c3eSSagi Grimberg pmdp_splitting_flush(vma, address, pmd); 165134ee645eSJoerg Roedel 165271e3aac0SAndrea Arcangeli ret = 1; 1653117b0791SKirill A. Shutemov spin_unlock(ptl); 165471e3aac0SAndrea Arcangeli } 16552ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 165671e3aac0SAndrea Arcangeli 165771e3aac0SAndrea Arcangeli return ret; 165871e3aac0SAndrea Arcangeli } 165971e3aac0SAndrea Arcangeli 16605bc7b8acSShaohua Li static void __split_huge_page_refcount(struct page *page, 16615bc7b8acSShaohua Li struct list_head *list) 166271e3aac0SAndrea Arcangeli { 166371e3aac0SAndrea Arcangeli int i; 166471e3aac0SAndrea Arcangeli struct zone *zone = page_zone(page); 1665fa9add64SHugh Dickins struct lruvec *lruvec; 166670b50f94SAndrea Arcangeli int tail_count = 0; 166771e3aac0SAndrea Arcangeli 166871e3aac0SAndrea Arcangeli /* prevent PageLRU to go away from under us, and freeze lru stats */ 166971e3aac0SAndrea Arcangeli spin_lock_irq(&zone->lru_lock); 1670fa9add64SHugh Dickins lruvec = mem_cgroup_page_lruvec(page, zone); 1671fa9add64SHugh Dickins 167271e3aac0SAndrea Arcangeli compound_lock(page); 1673e94c8a9cSKAMEZAWA Hiroyuki /* complete memcg works before add pages to LRU */ 1674e94c8a9cSKAMEZAWA Hiroyuki mem_cgroup_split_huge_fixup(page); 167571e3aac0SAndrea Arcangeli 167645676885SShaohua Li for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { 167771e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 167871e3aac0SAndrea Arcangeli 167970b50f94SAndrea Arcangeli /* tail_page->_mapcount cannot change */ 168070b50f94SAndrea Arcangeli BUG_ON(page_mapcount(page_tail) < 0); 168170b50f94SAndrea Arcangeli tail_count += page_mapcount(page_tail); 168270b50f94SAndrea Arcangeli /* check for overflow */ 168370b50f94SAndrea Arcangeli BUG_ON(tail_count < 0); 168470b50f94SAndrea Arcangeli BUG_ON(atomic_read(&page_tail->_count) != 0); 168570b50f94SAndrea Arcangeli /* 168670b50f94SAndrea Arcangeli * tail_page->_count is zero and not changing from 168770b50f94SAndrea Arcangeli * under us. But get_page_unless_zero() may be running 168870b50f94SAndrea Arcangeli * from under us on the tail_page. If we used 168970b50f94SAndrea Arcangeli * atomic_set() below instead of atomic_add(), we 169070b50f94SAndrea Arcangeli * would then run atomic_set() concurrently with 169170b50f94SAndrea Arcangeli * get_page_unless_zero(), and atomic_set() is 169270b50f94SAndrea Arcangeli * implemented in C not using locked ops. spin_unlock 169370b50f94SAndrea Arcangeli * on x86 sometime uses locked ops because of PPro 169470b50f94SAndrea Arcangeli * errata 66, 92, so unless somebody can guarantee 169570b50f94SAndrea Arcangeli * atomic_set() here would be safe on all archs (and 169670b50f94SAndrea Arcangeli * not only on x86), it's safer to use atomic_add(). 169770b50f94SAndrea Arcangeli */ 169870b50f94SAndrea Arcangeli atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, 169970b50f94SAndrea Arcangeli &page_tail->_count); 170071e3aac0SAndrea Arcangeli 170171e3aac0SAndrea Arcangeli /* after clearing PageTail the gup refcount can be released */ 17023a79d52aSWaiman Long smp_mb__after_atomic(); 170371e3aac0SAndrea Arcangeli 1704f4c18e6fSNaoya Horiguchi page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 170571e3aac0SAndrea Arcangeli page_tail->flags |= (page->flags & 170671e3aac0SAndrea Arcangeli ((1L << PG_referenced) | 170771e3aac0SAndrea Arcangeli (1L << PG_swapbacked) | 170871e3aac0SAndrea Arcangeli (1L << PG_mlocked) | 1709e180cf80SKirill A. Shutemov (1L << PG_uptodate) | 1710e180cf80SKirill A. Shutemov (1L << PG_active) | 1711e180cf80SKirill A. Shutemov (1L << PG_unevictable))); 171271e3aac0SAndrea Arcangeli page_tail->flags |= (1L << PG_dirty); 171371e3aac0SAndrea Arcangeli 171470b50f94SAndrea Arcangeli /* clear PageTail before overwriting first_page */ 171571e3aac0SAndrea Arcangeli smp_wmb(); 171671e3aac0SAndrea Arcangeli 171771e3aac0SAndrea Arcangeli /* 171871e3aac0SAndrea Arcangeli * __split_huge_page_splitting() already set the 171971e3aac0SAndrea Arcangeli * splitting bit in all pmd that could map this 172071e3aac0SAndrea Arcangeli * hugepage, that will ensure no CPU can alter the 172171e3aac0SAndrea Arcangeli * mapcount on the head page. The mapcount is only 172271e3aac0SAndrea Arcangeli * accounted in the head page and it has to be 172371e3aac0SAndrea Arcangeli * transferred to all tail pages in the below code. So 172471e3aac0SAndrea Arcangeli * for this code to be safe, the split the mapcount 172571e3aac0SAndrea Arcangeli * can't change. But that doesn't mean userland can't 172671e3aac0SAndrea Arcangeli * keep changing and reading the page contents while 172771e3aac0SAndrea Arcangeli * we transfer the mapcount, so the pmd splitting 172871e3aac0SAndrea Arcangeli * status is achieved setting a reserved bit in the 172971e3aac0SAndrea Arcangeli * pmd, not by clearing the present bit. 173071e3aac0SAndrea Arcangeli */ 173171e3aac0SAndrea Arcangeli page_tail->_mapcount = page->_mapcount; 173271e3aac0SAndrea Arcangeli 173371e3aac0SAndrea Arcangeli BUG_ON(page_tail->mapping); 173471e3aac0SAndrea Arcangeli page_tail->mapping = page->mapping; 173571e3aac0SAndrea Arcangeli 173645676885SShaohua Li page_tail->index = page->index + i; 173790572890SPeter Zijlstra page_cpupid_xchg_last(page_tail, page_cpupid_last(page)); 173871e3aac0SAndrea Arcangeli 173971e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page_tail)); 174071e3aac0SAndrea Arcangeli BUG_ON(!PageUptodate(page_tail)); 174171e3aac0SAndrea Arcangeli BUG_ON(!PageDirty(page_tail)); 174271e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page_tail)); 174371e3aac0SAndrea Arcangeli 17445bc7b8acSShaohua Li lru_add_page_tail(page, page_tail, lruvec, list); 174571e3aac0SAndrea Arcangeli } 174670b50f94SAndrea Arcangeli atomic_sub(tail_count, &page->_count); 174770b50f94SAndrea Arcangeli BUG_ON(atomic_read(&page->_count) <= 0); 174871e3aac0SAndrea Arcangeli 1749fa9add64SHugh Dickins __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); 175079134171SAndrea Arcangeli 175171e3aac0SAndrea Arcangeli ClearPageCompound(page); 175271e3aac0SAndrea Arcangeli compound_unlock(page); 175371e3aac0SAndrea Arcangeli spin_unlock_irq(&zone->lru_lock); 175471e3aac0SAndrea Arcangeli 175571e3aac0SAndrea Arcangeli for (i = 1; i < HPAGE_PMD_NR; i++) { 175671e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 175771e3aac0SAndrea Arcangeli BUG_ON(page_count(page_tail) <= 0); 175871e3aac0SAndrea Arcangeli /* 175971e3aac0SAndrea Arcangeli * Tail pages may be freed if there wasn't any mapping 176071e3aac0SAndrea Arcangeli * like if add_to_swap() is running on a lru page that 176171e3aac0SAndrea Arcangeli * had its mapping zapped. And freeing these pages 176271e3aac0SAndrea Arcangeli * requires taking the lru_lock so we do the put_page 176371e3aac0SAndrea Arcangeli * of the tail pages after the split is complete. 176471e3aac0SAndrea Arcangeli */ 176571e3aac0SAndrea Arcangeli put_page(page_tail); 176671e3aac0SAndrea Arcangeli } 176771e3aac0SAndrea Arcangeli 176871e3aac0SAndrea Arcangeli /* 176971e3aac0SAndrea Arcangeli * Only the head page (now become a regular page) is required 177071e3aac0SAndrea Arcangeli * to be pinned by the caller. 177171e3aac0SAndrea Arcangeli */ 177271e3aac0SAndrea Arcangeli BUG_ON(page_count(page) <= 0); 177371e3aac0SAndrea Arcangeli } 177471e3aac0SAndrea Arcangeli 177571e3aac0SAndrea Arcangeli static int __split_huge_page_map(struct page *page, 177671e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 177771e3aac0SAndrea Arcangeli unsigned long address) 177871e3aac0SAndrea Arcangeli { 177971e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 1780117b0791SKirill A. Shutemov spinlock_t *ptl; 178171e3aac0SAndrea Arcangeli pmd_t *pmd, _pmd; 178271e3aac0SAndrea Arcangeli int ret = 0, i; 178371e3aac0SAndrea Arcangeli pgtable_t pgtable; 178471e3aac0SAndrea Arcangeli unsigned long haddr; 178571e3aac0SAndrea Arcangeli 178671e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 1787117b0791SKirill A. Shutemov PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG, &ptl); 178871e3aac0SAndrea Arcangeli if (pmd) { 17896b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 179071e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 1791f8303c25SWaiman Long if (pmd_write(*pmd)) 1792f8303c25SWaiman Long BUG_ON(page_mapcount(page) != 1); 179371e3aac0SAndrea Arcangeli 1794e3ebcf64SGerald Schaefer haddr = address; 1795e3ebcf64SGerald Schaefer for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 179671e3aac0SAndrea Arcangeli pte_t *pte, entry; 179771e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page+i)); 1798abc40bd2SMel Gorman /* 17998a0516edSMel Gorman * Note that NUMA hinting access restrictions are not 18008a0516edSMel Gorman * transferred to avoid any possibility of altering 18018a0516edSMel Gorman * permissions across VMAs. 1802abc40bd2SMel Gorman */ 180371e3aac0SAndrea Arcangeli entry = mk_pte(page + i, vma->vm_page_prot); 180471e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 180571e3aac0SAndrea Arcangeli if (!pmd_write(*pmd)) 180671e3aac0SAndrea Arcangeli entry = pte_wrprotect(entry); 180771e3aac0SAndrea Arcangeli if (!pmd_young(*pmd)) 180871e3aac0SAndrea Arcangeli entry = pte_mkold(entry); 180971e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 181071e3aac0SAndrea Arcangeli BUG_ON(!pte_none(*pte)); 181171e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 181271e3aac0SAndrea Arcangeli pte_unmap(pte); 181371e3aac0SAndrea Arcangeli } 181471e3aac0SAndrea Arcangeli 181571e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 181671e3aac0SAndrea Arcangeli /* 181771e3aac0SAndrea Arcangeli * Up to this point the pmd is present and huge and 181871e3aac0SAndrea Arcangeli * userland has the whole access to the hugepage 181971e3aac0SAndrea Arcangeli * during the split (which happens in place). If we 182071e3aac0SAndrea Arcangeli * overwrite the pmd with the not-huge version 182171e3aac0SAndrea Arcangeli * pointing to the pte here (which of course we could 182271e3aac0SAndrea Arcangeli * if all CPUs were bug free), userland could trigger 182371e3aac0SAndrea Arcangeli * a small page size TLB miss on the small sized TLB 182471e3aac0SAndrea Arcangeli * while the hugepage TLB entry is still established 182571e3aac0SAndrea Arcangeli * in the huge TLB. Some CPU doesn't like that. See 182671e3aac0SAndrea Arcangeli * http://support.amd.com/us/Processor_TechDocs/41322.pdf, 182771e3aac0SAndrea Arcangeli * Erratum 383 on page 93. Intel should be safe but is 182871e3aac0SAndrea Arcangeli * also warns that it's only safe if the permission 182971e3aac0SAndrea Arcangeli * and cache attributes of the two entries loaded in 183071e3aac0SAndrea Arcangeli * the two TLB is identical (which should be the case 183171e3aac0SAndrea Arcangeli * here). But it is generally safer to never allow 183271e3aac0SAndrea Arcangeli * small and huge TLB entries for the same virtual 183371e3aac0SAndrea Arcangeli * address to be loaded simultaneously. So instead of 183471e3aac0SAndrea Arcangeli * doing "pmd_populate(); flush_tlb_range();" we first 183571e3aac0SAndrea Arcangeli * mark the current pmd notpresent (atomically because 183671e3aac0SAndrea Arcangeli * here the pmd_trans_huge and pmd_trans_splitting 183771e3aac0SAndrea Arcangeli * must remain set at all times on the pmd until the 183871e3aac0SAndrea Arcangeli * split is complete for this pmd), then we flush the 183971e3aac0SAndrea Arcangeli * SMP TLB and finally we write the non-huge version 184071e3aac0SAndrea Arcangeli * of the pmd entry with pmd_populate. 184171e3aac0SAndrea Arcangeli */ 184246dcde73SGerald Schaefer pmdp_invalidate(vma, address, pmd); 184371e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 184471e3aac0SAndrea Arcangeli ret = 1; 1845117b0791SKirill A. Shutemov spin_unlock(ptl); 184671e3aac0SAndrea Arcangeli } 184771e3aac0SAndrea Arcangeli 184871e3aac0SAndrea Arcangeli return ret; 184971e3aac0SAndrea Arcangeli } 185071e3aac0SAndrea Arcangeli 18515a505085SIngo Molnar /* must be called with anon_vma->root->rwsem held */ 185271e3aac0SAndrea Arcangeli static void __split_huge_page(struct page *page, 18535bc7b8acSShaohua Li struct anon_vma *anon_vma, 18545bc7b8acSShaohua Li struct list_head *list) 185571e3aac0SAndrea Arcangeli { 185671e3aac0SAndrea Arcangeli int mapcount, mapcount2; 1857bf181b9fSMichel Lespinasse pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); 185871e3aac0SAndrea Arcangeli struct anon_vma_chain *avc; 185971e3aac0SAndrea Arcangeli 186071e3aac0SAndrea Arcangeli BUG_ON(!PageHead(page)); 186171e3aac0SAndrea Arcangeli BUG_ON(PageTail(page)); 186271e3aac0SAndrea Arcangeli 186371e3aac0SAndrea Arcangeli mapcount = 0; 1864bf181b9fSMichel Lespinasse anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { 186571e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 186671e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 186771e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 186871e3aac0SAndrea Arcangeli mapcount += __split_huge_page_splitting(page, vma, addr); 186971e3aac0SAndrea Arcangeli } 187005759d38SAndrea Arcangeli /* 187105759d38SAndrea Arcangeli * It is critical that new vmas are added to the tail of the 187205759d38SAndrea Arcangeli * anon_vma list. This guarantes that if copy_huge_pmd() runs 187305759d38SAndrea Arcangeli * and establishes a child pmd before 187405759d38SAndrea Arcangeli * __split_huge_page_splitting() freezes the parent pmd (so if 187505759d38SAndrea Arcangeli * we fail to prevent copy_huge_pmd() from running until the 187605759d38SAndrea Arcangeli * whole __split_huge_page() is complete), we will still see 187705759d38SAndrea Arcangeli * the newly established pmd of the child later during the 187805759d38SAndrea Arcangeli * walk, to be able to set it as pmd_trans_splitting too. 187905759d38SAndrea Arcangeli */ 1880ff9e43ebSKirill A. Shutemov if (mapcount != page_mapcount(page)) { 1881ae3a8c1cSAndrew Morton pr_err("mapcount %d page_mapcount %d\n", 188205759d38SAndrea Arcangeli mapcount, page_mapcount(page)); 1883ff9e43ebSKirill A. Shutemov BUG(); 1884ff9e43ebSKirill A. Shutemov } 188571e3aac0SAndrea Arcangeli 18865bc7b8acSShaohua Li __split_huge_page_refcount(page, list); 188771e3aac0SAndrea Arcangeli 188871e3aac0SAndrea Arcangeli mapcount2 = 0; 1889bf181b9fSMichel Lespinasse anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { 189071e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 189171e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 189271e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 189371e3aac0SAndrea Arcangeli mapcount2 += __split_huge_page_map(page, vma, addr); 189471e3aac0SAndrea Arcangeli } 1895ff9e43ebSKirill A. Shutemov if (mapcount != mapcount2) { 1896ae3a8c1cSAndrew Morton pr_err("mapcount %d mapcount2 %d page_mapcount %d\n", 189705759d38SAndrea Arcangeli mapcount, mapcount2, page_mapcount(page)); 1898ff9e43ebSKirill A. Shutemov BUG(); 1899ff9e43ebSKirill A. Shutemov } 190071e3aac0SAndrea Arcangeli } 190171e3aac0SAndrea Arcangeli 19025bc7b8acSShaohua Li /* 19035bc7b8acSShaohua Li * Split a hugepage into normal pages. This doesn't change the position of head 19045bc7b8acSShaohua Li * page. If @list is null, tail pages will be added to LRU list, otherwise, to 19055bc7b8acSShaohua Li * @list. Both head page and tail pages will inherit mapping, flags, and so on 19065bc7b8acSShaohua Li * from the hugepage. 19075bc7b8acSShaohua Li * Return 0 if the hugepage is split successfully otherwise return 1. 19085bc7b8acSShaohua Li */ 19095bc7b8acSShaohua Li int split_huge_page_to_list(struct page *page, struct list_head *list) 191071e3aac0SAndrea Arcangeli { 191171e3aac0SAndrea Arcangeli struct anon_vma *anon_vma; 191271e3aac0SAndrea Arcangeli int ret = 1; 191371e3aac0SAndrea Arcangeli 19145918d10aSKirill A. Shutemov BUG_ON(is_huge_zero_page(page)); 191571e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page)); 1916062f1af2SMel Gorman 1917062f1af2SMel Gorman /* 1918062f1af2SMel Gorman * The caller does not necessarily hold an mmap_sem that would prevent 1919062f1af2SMel Gorman * the anon_vma disappearing so we first we take a reference to it 1920062f1af2SMel Gorman * and then lock the anon_vma for write. This is similar to 1921062f1af2SMel Gorman * page_lock_anon_vma_read except the write lock is taken to serialise 1922062f1af2SMel Gorman * against parallel split or collapse operations. 1923062f1af2SMel Gorman */ 1924062f1af2SMel Gorman anon_vma = page_get_anon_vma(page); 192571e3aac0SAndrea Arcangeli if (!anon_vma) 192671e3aac0SAndrea Arcangeli goto out; 1927062f1af2SMel Gorman anon_vma_lock_write(anon_vma); 1928062f1af2SMel Gorman 192971e3aac0SAndrea Arcangeli ret = 0; 193071e3aac0SAndrea Arcangeli if (!PageCompound(page)) 193171e3aac0SAndrea Arcangeli goto out_unlock; 193271e3aac0SAndrea Arcangeli 193371e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page)); 19345bc7b8acSShaohua Li __split_huge_page(page, anon_vma, list); 193581ab4201SAndi Kleen count_vm_event(THP_SPLIT); 193671e3aac0SAndrea Arcangeli 193771e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page)); 193871e3aac0SAndrea Arcangeli out_unlock: 193908b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 1940062f1af2SMel Gorman put_anon_vma(anon_vma); 194171e3aac0SAndrea Arcangeli out: 194271e3aac0SAndrea Arcangeli return ret; 194371e3aac0SAndrea Arcangeli } 194471e3aac0SAndrea Arcangeli 19459050d7ebSVlastimil Babka #define VM_NO_THP (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE) 194678f11a25SAndrea Arcangeli 194760ab3244SAndrea Arcangeli int hugepage_madvise(struct vm_area_struct *vma, 194860ab3244SAndrea Arcangeli unsigned long *vm_flags, int advice) 19490af4e98bSAndrea Arcangeli { 1950a664b2d8SAndrea Arcangeli switch (advice) { 1951a664b2d8SAndrea Arcangeli case MADV_HUGEPAGE: 19521e1836e8SAlex Thorlton #ifdef CONFIG_S390 19531e1836e8SAlex Thorlton /* 19541e1836e8SAlex Thorlton * qemu blindly sets MADV_HUGEPAGE on all allocations, but s390 19551e1836e8SAlex Thorlton * can't handle this properly after s390_enable_sie, so we simply 19561e1836e8SAlex Thorlton * ignore the madvise to prevent qemu from causing a SIGSEGV. 19571e1836e8SAlex Thorlton */ 19581e1836e8SAlex Thorlton if (mm_has_pgste(vma->vm_mm)) 19591e1836e8SAlex Thorlton return 0; 19601e1836e8SAlex Thorlton #endif 19610af4e98bSAndrea Arcangeli /* 19620af4e98bSAndrea Arcangeli * Be somewhat over-protective like KSM for now! 19630af4e98bSAndrea Arcangeli */ 196478f11a25SAndrea Arcangeli if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) 19650af4e98bSAndrea Arcangeli return -EINVAL; 1966a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_NOHUGEPAGE; 19670af4e98bSAndrea Arcangeli *vm_flags |= VM_HUGEPAGE; 196860ab3244SAndrea Arcangeli /* 196960ab3244SAndrea Arcangeli * If the vma become good for khugepaged to scan, 197060ab3244SAndrea Arcangeli * register it here without waiting a page fault that 197160ab3244SAndrea Arcangeli * may not happen any time soon. 197260ab3244SAndrea Arcangeli */ 19736d50e60cSDavid Rientjes if (unlikely(khugepaged_enter_vma_merge(vma, *vm_flags))) 197460ab3244SAndrea Arcangeli return -ENOMEM; 1975a664b2d8SAndrea Arcangeli break; 1976a664b2d8SAndrea Arcangeli case MADV_NOHUGEPAGE: 1977a664b2d8SAndrea Arcangeli /* 1978a664b2d8SAndrea Arcangeli * Be somewhat over-protective like KSM for now! 1979a664b2d8SAndrea Arcangeli */ 198078f11a25SAndrea Arcangeli if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) 1981a664b2d8SAndrea Arcangeli return -EINVAL; 1982a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_HUGEPAGE; 1983a664b2d8SAndrea Arcangeli *vm_flags |= VM_NOHUGEPAGE; 198460ab3244SAndrea Arcangeli /* 198560ab3244SAndrea Arcangeli * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning 198660ab3244SAndrea Arcangeli * this vma even if we leave the mm registered in khugepaged if 198760ab3244SAndrea Arcangeli * it got registered before VM_NOHUGEPAGE was set. 198860ab3244SAndrea Arcangeli */ 1989a664b2d8SAndrea Arcangeli break; 1990a664b2d8SAndrea Arcangeli } 19910af4e98bSAndrea Arcangeli 19920af4e98bSAndrea Arcangeli return 0; 19930af4e98bSAndrea Arcangeli } 19940af4e98bSAndrea Arcangeli 1995ba76149fSAndrea Arcangeli static int __init khugepaged_slab_init(void) 1996ba76149fSAndrea Arcangeli { 1997ba76149fSAndrea Arcangeli mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", 1998ba76149fSAndrea Arcangeli sizeof(struct mm_slot), 1999ba76149fSAndrea Arcangeli __alignof__(struct mm_slot), 0, NULL); 2000ba76149fSAndrea Arcangeli if (!mm_slot_cache) 2001ba76149fSAndrea Arcangeli return -ENOMEM; 2002ba76149fSAndrea Arcangeli 2003ba76149fSAndrea Arcangeli return 0; 2004ba76149fSAndrea Arcangeli } 2005ba76149fSAndrea Arcangeli 200665ebb64fSKirill A. Shutemov static void __init khugepaged_slab_exit(void) 200765ebb64fSKirill A. Shutemov { 200865ebb64fSKirill A. Shutemov kmem_cache_destroy(mm_slot_cache); 200965ebb64fSKirill A. Shutemov } 201065ebb64fSKirill A. Shutemov 2011ba76149fSAndrea Arcangeli static inline struct mm_slot *alloc_mm_slot(void) 2012ba76149fSAndrea Arcangeli { 2013ba76149fSAndrea Arcangeli if (!mm_slot_cache) /* initialization failed */ 2014ba76149fSAndrea Arcangeli return NULL; 2015ba76149fSAndrea Arcangeli return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); 2016ba76149fSAndrea Arcangeli } 2017ba76149fSAndrea Arcangeli 2018ba76149fSAndrea Arcangeli static inline void free_mm_slot(struct mm_slot *mm_slot) 2019ba76149fSAndrea Arcangeli { 2020ba76149fSAndrea Arcangeli kmem_cache_free(mm_slot_cache, mm_slot); 2021ba76149fSAndrea Arcangeli } 2022ba76149fSAndrea Arcangeli 2023ba76149fSAndrea Arcangeli static struct mm_slot *get_mm_slot(struct mm_struct *mm) 2024ba76149fSAndrea Arcangeli { 2025ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2026ba76149fSAndrea Arcangeli 2027b67bfe0dSSasha Levin hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm) 2028ba76149fSAndrea Arcangeli if (mm == mm_slot->mm) 2029ba76149fSAndrea Arcangeli return mm_slot; 203043b5fbbdSSasha Levin 2031ba76149fSAndrea Arcangeli return NULL; 2032ba76149fSAndrea Arcangeli } 2033ba76149fSAndrea Arcangeli 2034ba76149fSAndrea Arcangeli static void insert_to_mm_slots_hash(struct mm_struct *mm, 2035ba76149fSAndrea Arcangeli struct mm_slot *mm_slot) 2036ba76149fSAndrea Arcangeli { 2037ba76149fSAndrea Arcangeli mm_slot->mm = mm; 203843b5fbbdSSasha Levin hash_add(mm_slots_hash, &mm_slot->hash, (long)mm); 2039ba76149fSAndrea Arcangeli } 2040ba76149fSAndrea Arcangeli 2041ba76149fSAndrea Arcangeli static inline int khugepaged_test_exit(struct mm_struct *mm) 2042ba76149fSAndrea Arcangeli { 2043ba76149fSAndrea Arcangeli return atomic_read(&mm->mm_users) == 0; 2044ba76149fSAndrea Arcangeli } 2045ba76149fSAndrea Arcangeli 2046ba76149fSAndrea Arcangeli int __khugepaged_enter(struct mm_struct *mm) 2047ba76149fSAndrea Arcangeli { 2048ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2049ba76149fSAndrea Arcangeli int wakeup; 2050ba76149fSAndrea Arcangeli 2051ba76149fSAndrea Arcangeli mm_slot = alloc_mm_slot(); 2052ba76149fSAndrea Arcangeli if (!mm_slot) 2053ba76149fSAndrea Arcangeli return -ENOMEM; 2054ba76149fSAndrea Arcangeli 2055ba76149fSAndrea Arcangeli /* __khugepaged_exit() must not run from under us */ 205696dad67fSSasha Levin VM_BUG_ON_MM(khugepaged_test_exit(mm), mm); 2057ba76149fSAndrea Arcangeli if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { 2058ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2059ba76149fSAndrea Arcangeli return 0; 2060ba76149fSAndrea Arcangeli } 2061ba76149fSAndrea Arcangeli 2062ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2063ba76149fSAndrea Arcangeli insert_to_mm_slots_hash(mm, mm_slot); 2064ba76149fSAndrea Arcangeli /* 2065ba76149fSAndrea Arcangeli * Insert just behind the scanning cursor, to let the area settle 2066ba76149fSAndrea Arcangeli * down a little. 2067ba76149fSAndrea Arcangeli */ 2068ba76149fSAndrea Arcangeli wakeup = list_empty(&khugepaged_scan.mm_head); 2069ba76149fSAndrea Arcangeli list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); 2070ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2071ba76149fSAndrea Arcangeli 2072ba76149fSAndrea Arcangeli atomic_inc(&mm->mm_count); 2073ba76149fSAndrea Arcangeli if (wakeup) 2074ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 2075ba76149fSAndrea Arcangeli 2076ba76149fSAndrea Arcangeli return 0; 2077ba76149fSAndrea Arcangeli } 2078ba76149fSAndrea Arcangeli 20796d50e60cSDavid Rientjes int khugepaged_enter_vma_merge(struct vm_area_struct *vma, 20806d50e60cSDavid Rientjes unsigned long vm_flags) 2081ba76149fSAndrea Arcangeli { 2082ba76149fSAndrea Arcangeli unsigned long hstart, hend; 2083ba76149fSAndrea Arcangeli if (!vma->anon_vma) 2084ba76149fSAndrea Arcangeli /* 2085ba76149fSAndrea Arcangeli * Not yet faulted in so we will register later in the 2086ba76149fSAndrea Arcangeli * page fault if needed. 2087ba76149fSAndrea Arcangeli */ 2088ba76149fSAndrea Arcangeli return 0; 208978f11a25SAndrea Arcangeli if (vma->vm_ops) 2090ba76149fSAndrea Arcangeli /* khugepaged not yet working on file or special mappings */ 2091ba76149fSAndrea Arcangeli return 0; 20926d50e60cSDavid Rientjes VM_BUG_ON_VMA(vm_flags & VM_NO_THP, vma); 2093ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2094ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2095ba76149fSAndrea Arcangeli if (hstart < hend) 20966d50e60cSDavid Rientjes return khugepaged_enter(vma, vm_flags); 2097ba76149fSAndrea Arcangeli return 0; 2098ba76149fSAndrea Arcangeli } 2099ba76149fSAndrea Arcangeli 2100ba76149fSAndrea Arcangeli void __khugepaged_exit(struct mm_struct *mm) 2101ba76149fSAndrea Arcangeli { 2102ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2103ba76149fSAndrea Arcangeli int free = 0; 2104ba76149fSAndrea Arcangeli 2105ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2106ba76149fSAndrea Arcangeli mm_slot = get_mm_slot(mm); 2107ba76149fSAndrea Arcangeli if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { 210843b5fbbdSSasha Levin hash_del(&mm_slot->hash); 2109ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 2110ba76149fSAndrea Arcangeli free = 1; 2111ba76149fSAndrea Arcangeli } 2112d788e80aSChris Wright spin_unlock(&khugepaged_mm_lock); 2113ba76149fSAndrea Arcangeli 2114ba76149fSAndrea Arcangeli if (free) { 2115ba76149fSAndrea Arcangeli clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 2116ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2117ba76149fSAndrea Arcangeli mmdrop(mm); 2118ba76149fSAndrea Arcangeli } else if (mm_slot) { 2119ba76149fSAndrea Arcangeli /* 2120ba76149fSAndrea Arcangeli * This is required to serialize against 2121ba76149fSAndrea Arcangeli * khugepaged_test_exit() (which is guaranteed to run 2122ba76149fSAndrea Arcangeli * under mmap sem read mode). Stop here (after we 2123ba76149fSAndrea Arcangeli * return all pagetables will be destroyed) until 2124ba76149fSAndrea Arcangeli * khugepaged has finished working on the pagetables 2125ba76149fSAndrea Arcangeli * under the mmap_sem. 2126ba76149fSAndrea Arcangeli */ 2127ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 2128ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 2129d788e80aSChris Wright } 2130ba76149fSAndrea Arcangeli } 2131ba76149fSAndrea Arcangeli 2132ba76149fSAndrea Arcangeli static void release_pte_page(struct page *page) 2133ba76149fSAndrea Arcangeli { 2134ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 2135ba76149fSAndrea Arcangeli dec_zone_page_state(page, NR_ISOLATED_ANON + 0); 2136ba76149fSAndrea Arcangeli unlock_page(page); 2137ba76149fSAndrea Arcangeli putback_lru_page(page); 2138ba76149fSAndrea Arcangeli } 2139ba76149fSAndrea Arcangeli 2140ba76149fSAndrea Arcangeli static void release_pte_pages(pte_t *pte, pte_t *_pte) 2141ba76149fSAndrea Arcangeli { 2142ba76149fSAndrea Arcangeli while (--_pte >= pte) { 2143ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2144ca0984caSEbru Akagunduz if (!pte_none(pteval) && !is_zero_pfn(pte_pfn(pteval))) 2145ba76149fSAndrea Arcangeli release_pte_page(pte_page(pteval)); 2146ba76149fSAndrea Arcangeli } 2147ba76149fSAndrea Arcangeli } 2148ba76149fSAndrea Arcangeli 2149ba76149fSAndrea Arcangeli static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 2150ba76149fSAndrea Arcangeli unsigned long address, 2151ba76149fSAndrea Arcangeli pte_t *pte) 2152ba76149fSAndrea Arcangeli { 2153ba76149fSAndrea Arcangeli struct page *page; 2154ba76149fSAndrea Arcangeli pte_t *_pte; 2155ca0984caSEbru Akagunduz int none_or_zero = 0; 215610359213SEbru Akagunduz bool referenced = false, writable = false; 2157ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; 2158ba76149fSAndrea Arcangeli _pte++, address += PAGE_SIZE) { 2159ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2160ca0984caSEbru Akagunduz if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { 2161ca0984caSEbru Akagunduz if (++none_or_zero <= khugepaged_max_ptes_none) 2162ba76149fSAndrea Arcangeli continue; 2163344aa35cSBob Liu else 2164ba76149fSAndrea Arcangeli goto out; 2165ba76149fSAndrea Arcangeli } 216610359213SEbru Akagunduz if (!pte_present(pteval)) 2167ba76149fSAndrea Arcangeli goto out; 2168ba76149fSAndrea Arcangeli page = vm_normal_page(vma, address, pteval); 2169344aa35cSBob Liu if (unlikely(!page)) 2170ba76149fSAndrea Arcangeli goto out; 2171344aa35cSBob Liu 2172309381feSSasha Levin VM_BUG_ON_PAGE(PageCompound(page), page); 2173309381feSSasha Levin VM_BUG_ON_PAGE(!PageAnon(page), page); 2174309381feSSasha Levin VM_BUG_ON_PAGE(!PageSwapBacked(page), page); 2175ba76149fSAndrea Arcangeli 2176ba76149fSAndrea Arcangeli /* 2177ba76149fSAndrea Arcangeli * We can do it before isolate_lru_page because the 2178ba76149fSAndrea Arcangeli * page can't be freed from under us. NOTE: PG_lock 2179ba76149fSAndrea Arcangeli * is needed to serialize against split_huge_page 2180ba76149fSAndrea Arcangeli * when invoked from the VM. 2181ba76149fSAndrea Arcangeli */ 2182344aa35cSBob Liu if (!trylock_page(page)) 2183ba76149fSAndrea Arcangeli goto out; 218410359213SEbru Akagunduz 218510359213SEbru Akagunduz /* 218610359213SEbru Akagunduz * cannot use mapcount: can't collapse if there's a gup pin. 218710359213SEbru Akagunduz * The page must only be referenced by the scanned process 218810359213SEbru Akagunduz * and page swap cache. 218910359213SEbru Akagunduz */ 219010359213SEbru Akagunduz if (page_count(page) != 1 + !!PageSwapCache(page)) { 219110359213SEbru Akagunduz unlock_page(page); 219210359213SEbru Akagunduz goto out; 219310359213SEbru Akagunduz } 219410359213SEbru Akagunduz if (pte_write(pteval)) { 219510359213SEbru Akagunduz writable = true; 219610359213SEbru Akagunduz } else { 219710359213SEbru Akagunduz if (PageSwapCache(page) && !reuse_swap_page(page)) { 219810359213SEbru Akagunduz unlock_page(page); 219910359213SEbru Akagunduz goto out; 220010359213SEbru Akagunduz } 220110359213SEbru Akagunduz /* 220210359213SEbru Akagunduz * Page is not in the swap cache. It can be collapsed 220310359213SEbru Akagunduz * into a THP. 220410359213SEbru Akagunduz */ 220510359213SEbru Akagunduz } 220610359213SEbru Akagunduz 2207ba76149fSAndrea Arcangeli /* 2208ba76149fSAndrea Arcangeli * Isolate the page to avoid collapsing an hugepage 2209ba76149fSAndrea Arcangeli * currently in use by the VM. 2210ba76149fSAndrea Arcangeli */ 2211ba76149fSAndrea Arcangeli if (isolate_lru_page(page)) { 2212ba76149fSAndrea Arcangeli unlock_page(page); 2213ba76149fSAndrea Arcangeli goto out; 2214ba76149fSAndrea Arcangeli } 2215ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 2216ba76149fSAndrea Arcangeli inc_zone_page_state(page, NR_ISOLATED_ANON + 0); 2217309381feSSasha Levin VM_BUG_ON_PAGE(!PageLocked(page), page); 2218309381feSSasha Levin VM_BUG_ON_PAGE(PageLRU(page), page); 2219ba76149fSAndrea Arcangeli 2220ba76149fSAndrea Arcangeli /* If there is no mapped pte young don't collapse the page */ 22218ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 22228ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 222310359213SEbru Akagunduz referenced = true; 2224ba76149fSAndrea Arcangeli } 222510359213SEbru Akagunduz if (likely(referenced && writable)) 2226344aa35cSBob Liu return 1; 2227ba76149fSAndrea Arcangeli out: 2228344aa35cSBob Liu release_pte_pages(pte, _pte); 2229344aa35cSBob Liu return 0; 2230ba76149fSAndrea Arcangeli } 2231ba76149fSAndrea Arcangeli 2232ba76149fSAndrea Arcangeli static void __collapse_huge_page_copy(pte_t *pte, struct page *page, 2233ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 2234ba76149fSAndrea Arcangeli unsigned long address, 2235ba76149fSAndrea Arcangeli spinlock_t *ptl) 2236ba76149fSAndrea Arcangeli { 2237ba76149fSAndrea Arcangeli pte_t *_pte; 2238ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { 2239ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2240ba76149fSAndrea Arcangeli struct page *src_page; 2241ba76149fSAndrea Arcangeli 2242ca0984caSEbru Akagunduz if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { 2243ba76149fSAndrea Arcangeli clear_user_highpage(page, address); 2244ba76149fSAndrea Arcangeli add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); 2245ca0984caSEbru Akagunduz if (is_zero_pfn(pte_pfn(pteval))) { 2246ca0984caSEbru Akagunduz /* 2247ca0984caSEbru Akagunduz * ptl mostly unnecessary. 2248ca0984caSEbru Akagunduz */ 2249ca0984caSEbru Akagunduz spin_lock(ptl); 2250ca0984caSEbru Akagunduz /* 2251ca0984caSEbru Akagunduz * paravirt calls inside pte_clear here are 2252ca0984caSEbru Akagunduz * superfluous. 2253ca0984caSEbru Akagunduz */ 2254ca0984caSEbru Akagunduz pte_clear(vma->vm_mm, address, _pte); 2255ca0984caSEbru Akagunduz spin_unlock(ptl); 2256ca0984caSEbru Akagunduz } 2257ba76149fSAndrea Arcangeli } else { 2258ba76149fSAndrea Arcangeli src_page = pte_page(pteval); 2259ba76149fSAndrea Arcangeli copy_user_highpage(page, src_page, address, vma); 2260309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page); 2261ba76149fSAndrea Arcangeli release_pte_page(src_page); 2262ba76149fSAndrea Arcangeli /* 2263ba76149fSAndrea Arcangeli * ptl mostly unnecessary, but preempt has to 2264ba76149fSAndrea Arcangeli * be disabled to update the per-cpu stats 2265ba76149fSAndrea Arcangeli * inside page_remove_rmap(). 2266ba76149fSAndrea Arcangeli */ 2267ba76149fSAndrea Arcangeli spin_lock(ptl); 2268ba76149fSAndrea Arcangeli /* 2269ba76149fSAndrea Arcangeli * paravirt calls inside pte_clear here are 2270ba76149fSAndrea Arcangeli * superfluous. 2271ba76149fSAndrea Arcangeli */ 2272ba76149fSAndrea Arcangeli pte_clear(vma->vm_mm, address, _pte); 2273ba76149fSAndrea Arcangeli page_remove_rmap(src_page); 2274ba76149fSAndrea Arcangeli spin_unlock(ptl); 2275ba76149fSAndrea Arcangeli free_page_and_swap_cache(src_page); 2276ba76149fSAndrea Arcangeli } 2277ba76149fSAndrea Arcangeli 2278ba76149fSAndrea Arcangeli address += PAGE_SIZE; 2279ba76149fSAndrea Arcangeli page++; 2280ba76149fSAndrea Arcangeli } 2281ba76149fSAndrea Arcangeli } 2282ba76149fSAndrea Arcangeli 228326234f36SXiao Guangrong static void khugepaged_alloc_sleep(void) 228426234f36SXiao Guangrong { 228526234f36SXiao Guangrong wait_event_freezable_timeout(khugepaged_wait, false, 228626234f36SXiao Guangrong msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); 228726234f36SXiao Guangrong } 228826234f36SXiao Guangrong 22899f1b868aSBob Liu static int khugepaged_node_load[MAX_NUMNODES]; 22909f1b868aSBob Liu 229114a4e214SDavid Rientjes static bool khugepaged_scan_abort(int nid) 229214a4e214SDavid Rientjes { 229314a4e214SDavid Rientjes int i; 229414a4e214SDavid Rientjes 229514a4e214SDavid Rientjes /* 229614a4e214SDavid Rientjes * If zone_reclaim_mode is disabled, then no extra effort is made to 229714a4e214SDavid Rientjes * allocate memory locally. 229814a4e214SDavid Rientjes */ 229914a4e214SDavid Rientjes if (!zone_reclaim_mode) 230014a4e214SDavid Rientjes return false; 230114a4e214SDavid Rientjes 230214a4e214SDavid Rientjes /* If there is a count for this node already, it must be acceptable */ 230314a4e214SDavid Rientjes if (khugepaged_node_load[nid]) 230414a4e214SDavid Rientjes return false; 230514a4e214SDavid Rientjes 230614a4e214SDavid Rientjes for (i = 0; i < MAX_NUMNODES; i++) { 230714a4e214SDavid Rientjes if (!khugepaged_node_load[i]) 230814a4e214SDavid Rientjes continue; 230914a4e214SDavid Rientjes if (node_distance(nid, i) > RECLAIM_DISTANCE) 231014a4e214SDavid Rientjes return true; 231114a4e214SDavid Rientjes } 231214a4e214SDavid Rientjes return false; 231314a4e214SDavid Rientjes } 231414a4e214SDavid Rientjes 231526234f36SXiao Guangrong #ifdef CONFIG_NUMA 23169f1b868aSBob Liu static int khugepaged_find_target_node(void) 23179f1b868aSBob Liu { 23189f1b868aSBob Liu static int last_khugepaged_target_node = NUMA_NO_NODE; 23199f1b868aSBob Liu int nid, target_node = 0, max_value = 0; 23209f1b868aSBob Liu 23219f1b868aSBob Liu /* find first node with max normal pages hit */ 23229f1b868aSBob Liu for (nid = 0; nid < MAX_NUMNODES; nid++) 23239f1b868aSBob Liu if (khugepaged_node_load[nid] > max_value) { 23249f1b868aSBob Liu max_value = khugepaged_node_load[nid]; 23259f1b868aSBob Liu target_node = nid; 23269f1b868aSBob Liu } 23279f1b868aSBob Liu 23289f1b868aSBob Liu /* do some balance if several nodes have the same hit record */ 23299f1b868aSBob Liu if (target_node <= last_khugepaged_target_node) 23309f1b868aSBob Liu for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES; 23319f1b868aSBob Liu nid++) 23329f1b868aSBob Liu if (max_value == khugepaged_node_load[nid]) { 23339f1b868aSBob Liu target_node = nid; 23349f1b868aSBob Liu break; 23359f1b868aSBob Liu } 23369f1b868aSBob Liu 23379f1b868aSBob Liu last_khugepaged_target_node = target_node; 23389f1b868aSBob Liu return target_node; 23399f1b868aSBob Liu } 23409f1b868aSBob Liu 234126234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 234226234f36SXiao Guangrong { 234326234f36SXiao Guangrong if (IS_ERR(*hpage)) { 234426234f36SXiao Guangrong if (!*wait) 234526234f36SXiao Guangrong return false; 234626234f36SXiao Guangrong 234726234f36SXiao Guangrong *wait = false; 2348e3b4126cSXiao Guangrong *hpage = NULL; 234926234f36SXiao Guangrong khugepaged_alloc_sleep(); 235026234f36SXiao Guangrong } else if (*hpage) { 235126234f36SXiao Guangrong put_page(*hpage); 235226234f36SXiao Guangrong *hpage = NULL; 235326234f36SXiao Guangrong } 235426234f36SXiao Guangrong 235526234f36SXiao Guangrong return true; 235626234f36SXiao Guangrong } 235726234f36SXiao Guangrong 23583b363692SMichal Hocko static struct page * 23593b363692SMichal Hocko khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm, 236026234f36SXiao Guangrong struct vm_area_struct *vma, unsigned long address, 236126234f36SXiao Guangrong int node) 236226234f36SXiao Guangrong { 2363309381feSSasha Levin VM_BUG_ON_PAGE(*hpage, *hpage); 23648b164568SVlastimil Babka 236526234f36SXiao Guangrong /* 23668b164568SVlastimil Babka * Before allocating the hugepage, release the mmap_sem read lock. 23678b164568SVlastimil Babka * The allocation can take potentially a long time if it involves 23688b164568SVlastimil Babka * sync compaction, and we do not need to hold the mmap_sem during 23698b164568SVlastimil Babka * that. We will recheck the vma after taking it again in write mode. 237026234f36SXiao Guangrong */ 237126234f36SXiao Guangrong up_read(&mm->mmap_sem); 23728b164568SVlastimil Babka 23733b363692SMichal Hocko *hpage = alloc_pages_exact_node(node, gfp, HPAGE_PMD_ORDER); 237426234f36SXiao Guangrong if (unlikely(!*hpage)) { 237526234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 237626234f36SXiao Guangrong *hpage = ERR_PTR(-ENOMEM); 237726234f36SXiao Guangrong return NULL; 237826234f36SXiao Guangrong } 237926234f36SXiao Guangrong 238026234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 238126234f36SXiao Guangrong return *hpage; 238226234f36SXiao Guangrong } 238326234f36SXiao Guangrong #else 23849f1b868aSBob Liu static int khugepaged_find_target_node(void) 23859f1b868aSBob Liu { 23869f1b868aSBob Liu return 0; 23879f1b868aSBob Liu } 23889f1b868aSBob Liu 238910dc4155SBob Liu static inline struct page *alloc_hugepage(int defrag) 239010dc4155SBob Liu { 239110dc4155SBob Liu return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), 239210dc4155SBob Liu HPAGE_PMD_ORDER); 239310dc4155SBob Liu } 239410dc4155SBob Liu 239526234f36SXiao Guangrong static struct page *khugepaged_alloc_hugepage(bool *wait) 239626234f36SXiao Guangrong { 239726234f36SXiao Guangrong struct page *hpage; 239826234f36SXiao Guangrong 239926234f36SXiao Guangrong do { 240026234f36SXiao Guangrong hpage = alloc_hugepage(khugepaged_defrag()); 240126234f36SXiao Guangrong if (!hpage) { 240226234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 240326234f36SXiao Guangrong if (!*wait) 240426234f36SXiao Guangrong return NULL; 240526234f36SXiao Guangrong 240626234f36SXiao Guangrong *wait = false; 240726234f36SXiao Guangrong khugepaged_alloc_sleep(); 240826234f36SXiao Guangrong } else 240926234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 241026234f36SXiao Guangrong } while (unlikely(!hpage) && likely(khugepaged_enabled())); 241126234f36SXiao Guangrong 241226234f36SXiao Guangrong return hpage; 241326234f36SXiao Guangrong } 241426234f36SXiao Guangrong 241526234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 241626234f36SXiao Guangrong { 241726234f36SXiao Guangrong if (!*hpage) 241826234f36SXiao Guangrong *hpage = khugepaged_alloc_hugepage(wait); 241926234f36SXiao Guangrong 242026234f36SXiao Guangrong if (unlikely(!*hpage)) 242126234f36SXiao Guangrong return false; 242226234f36SXiao Guangrong 242326234f36SXiao Guangrong return true; 242426234f36SXiao Guangrong } 242526234f36SXiao Guangrong 24263b363692SMichal Hocko static struct page * 24273b363692SMichal Hocko khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm, 242826234f36SXiao Guangrong struct vm_area_struct *vma, unsigned long address, 242926234f36SXiao Guangrong int node) 243026234f36SXiao Guangrong { 243126234f36SXiao Guangrong up_read(&mm->mmap_sem); 243226234f36SXiao Guangrong VM_BUG_ON(!*hpage); 24333b363692SMichal Hocko 243426234f36SXiao Guangrong return *hpage; 243526234f36SXiao Guangrong } 243626234f36SXiao Guangrong #endif 243726234f36SXiao Guangrong 2438fa475e51SBob Liu static bool hugepage_vma_check(struct vm_area_struct *vma) 2439fa475e51SBob Liu { 2440fa475e51SBob Liu if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || 2441fa475e51SBob Liu (vma->vm_flags & VM_NOHUGEPAGE)) 2442fa475e51SBob Liu return false; 2443fa475e51SBob Liu 2444fa475e51SBob Liu if (!vma->anon_vma || vma->vm_ops) 2445fa475e51SBob Liu return false; 2446fa475e51SBob Liu if (is_vma_temporary_stack(vma)) 2447fa475e51SBob Liu return false; 244881d1b09cSSasha Levin VM_BUG_ON_VMA(vma->vm_flags & VM_NO_THP, vma); 2449fa475e51SBob Liu return true; 2450fa475e51SBob Liu } 2451fa475e51SBob Liu 2452ba76149fSAndrea Arcangeli static void collapse_huge_page(struct mm_struct *mm, 2453ba76149fSAndrea Arcangeli unsigned long address, 2454ce83d217SAndrea Arcangeli struct page **hpage, 24555c4b4be3SAndi Kleen struct vm_area_struct *vma, 24565c4b4be3SAndi Kleen int node) 2457ba76149fSAndrea Arcangeli { 2458ba76149fSAndrea Arcangeli pmd_t *pmd, _pmd; 2459ba76149fSAndrea Arcangeli pte_t *pte; 2460ba76149fSAndrea Arcangeli pgtable_t pgtable; 2461ba76149fSAndrea Arcangeli struct page *new_page; 2462c4088ebdSKirill A. Shutemov spinlock_t *pmd_ptl, *pte_ptl; 2463ba76149fSAndrea Arcangeli int isolated; 2464ba76149fSAndrea Arcangeli unsigned long hstart, hend; 246500501b53SJohannes Weiner struct mem_cgroup *memcg; 24662ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 24672ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 24683b363692SMichal Hocko gfp_t gfp; 2469ba76149fSAndrea Arcangeli 2470ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 2471692e0b35SAndrea Arcangeli 24723b363692SMichal Hocko /* Only allocate from the target node */ 24733b363692SMichal Hocko gfp = alloc_hugepage_gfpmask(khugepaged_defrag(), __GFP_OTHER_NODE) | 24743b363692SMichal Hocko __GFP_THISNODE; 24753b363692SMichal Hocko 247626234f36SXiao Guangrong /* release the mmap_sem read lock. */ 24773b363692SMichal Hocko new_page = khugepaged_alloc_page(hpage, gfp, mm, vma, address, node); 247826234f36SXiao Guangrong if (!new_page) 2479ce83d217SAndrea Arcangeli return; 2480ce83d217SAndrea Arcangeli 248100501b53SJohannes Weiner if (unlikely(mem_cgroup_try_charge(new_page, mm, 24823b363692SMichal Hocko gfp, &memcg))) 2483692e0b35SAndrea Arcangeli return; 2484ba76149fSAndrea Arcangeli 2485ba76149fSAndrea Arcangeli /* 2486ba76149fSAndrea Arcangeli * Prevent all access to pagetables with the exception of 2487ba76149fSAndrea Arcangeli * gup_fast later hanlded by the ptep_clear_flush and the VM 2488ba76149fSAndrea Arcangeli * handled by the anon_vma lock + PG_lock. 2489ba76149fSAndrea Arcangeli */ 2490ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 2491ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2492ba76149fSAndrea Arcangeli goto out; 2493ba76149fSAndrea Arcangeli 2494ba76149fSAndrea Arcangeli vma = find_vma(mm, address); 2495a8f531ebSLibin if (!vma) 2496a8f531ebSLibin goto out; 2497ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2498ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2499ba76149fSAndrea Arcangeli if (address < hstart || address + HPAGE_PMD_SIZE > hend) 2500ba76149fSAndrea Arcangeli goto out; 2501fa475e51SBob Liu if (!hugepage_vma_check(vma)) 2502ba76149fSAndrea Arcangeli goto out; 25036219049aSBob Liu pmd = mm_find_pmd(mm, address); 25046219049aSBob Liu if (!pmd) 2505ba76149fSAndrea Arcangeli goto out; 2506ba76149fSAndrea Arcangeli 25074fc3f1d6SIngo Molnar anon_vma_lock_write(vma->anon_vma); 2508ba76149fSAndrea Arcangeli 2509ba76149fSAndrea Arcangeli pte = pte_offset_map(pmd, address); 2510c4088ebdSKirill A. Shutemov pte_ptl = pte_lockptr(mm, pmd); 2511ba76149fSAndrea Arcangeli 25122ec74c3eSSagi Grimberg mmun_start = address; 25132ec74c3eSSagi Grimberg mmun_end = address + HPAGE_PMD_SIZE; 25142ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2515c4088ebdSKirill A. Shutemov pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */ 2516ba76149fSAndrea Arcangeli /* 2517ba76149fSAndrea Arcangeli * After this gup_fast can't run anymore. This also removes 2518ba76149fSAndrea Arcangeli * any huge TLB entry from the CPU so we won't allow 2519ba76149fSAndrea Arcangeli * huge and small TLB entries for the same virtual address 2520ba76149fSAndrea Arcangeli * to avoid the risk of CPU bugs in that area. 2521ba76149fSAndrea Arcangeli */ 252215a25b2eSAneesh Kumar K.V _pmd = pmdp_collapse_flush(vma, address, pmd); 2523c4088ebdSKirill A. Shutemov spin_unlock(pmd_ptl); 25242ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2525ba76149fSAndrea Arcangeli 2526c4088ebdSKirill A. Shutemov spin_lock(pte_ptl); 2527ba76149fSAndrea Arcangeli isolated = __collapse_huge_page_isolate(vma, address, pte); 2528c4088ebdSKirill A. Shutemov spin_unlock(pte_ptl); 2529ba76149fSAndrea Arcangeli 2530ba76149fSAndrea Arcangeli if (unlikely(!isolated)) { 2531453c7192SJohannes Weiner pte_unmap(pte); 2532c4088ebdSKirill A. Shutemov spin_lock(pmd_ptl); 2533ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 25347c342512SAneesh Kumar K.V /* 25357c342512SAneesh Kumar K.V * We can only use set_pmd_at when establishing 25367c342512SAneesh Kumar K.V * hugepmds and never for establishing regular pmds that 25377c342512SAneesh Kumar K.V * points to regular pagetables. Use pmd_populate for that 25387c342512SAneesh Kumar K.V */ 25397c342512SAneesh Kumar K.V pmd_populate(mm, pmd, pmd_pgtable(_pmd)); 2540c4088ebdSKirill A. Shutemov spin_unlock(pmd_ptl); 254108b52706SKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2542ce83d217SAndrea Arcangeli goto out; 2543ba76149fSAndrea Arcangeli } 2544ba76149fSAndrea Arcangeli 2545ba76149fSAndrea Arcangeli /* 2546ba76149fSAndrea Arcangeli * All pages are isolated and locked so anon_vma rmap 2547ba76149fSAndrea Arcangeli * can't run anymore. 2548ba76149fSAndrea Arcangeli */ 254908b52706SKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2550ba76149fSAndrea Arcangeli 2551c4088ebdSKirill A. Shutemov __collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl); 2552453c7192SJohannes Weiner pte_unmap(pte); 2553ba76149fSAndrea Arcangeli __SetPageUptodate(new_page); 2554ba76149fSAndrea Arcangeli pgtable = pmd_pgtable(_pmd); 2555ba76149fSAndrea Arcangeli 25563122359aSKirill A. Shutemov _pmd = mk_huge_pmd(new_page, vma->vm_page_prot); 25573122359aSKirill A. Shutemov _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); 2558ba76149fSAndrea Arcangeli 2559ba76149fSAndrea Arcangeli /* 2560ba76149fSAndrea Arcangeli * spin_lock() below is not the equivalent of smp_wmb(), so 2561ba76149fSAndrea Arcangeli * this is needed to avoid the copy_huge_page writes to become 2562ba76149fSAndrea Arcangeli * visible after the set_pmd_at() write. 2563ba76149fSAndrea Arcangeli */ 2564ba76149fSAndrea Arcangeli smp_wmb(); 2565ba76149fSAndrea Arcangeli 2566c4088ebdSKirill A. Shutemov spin_lock(pmd_ptl); 2567ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 2568ba76149fSAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, address); 256900501b53SJohannes Weiner mem_cgroup_commit_charge(new_page, memcg, false); 257000501b53SJohannes Weiner lru_cache_add_active_or_unevictable(new_page, vma); 2571fce144b4SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 2572ba76149fSAndrea Arcangeli set_pmd_at(mm, address, pmd, _pmd); 2573b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 2574c4088ebdSKirill A. Shutemov spin_unlock(pmd_ptl); 2575ba76149fSAndrea Arcangeli 2576ba76149fSAndrea Arcangeli *hpage = NULL; 2577420256efSXiao Guangrong 2578ba76149fSAndrea Arcangeli khugepaged_pages_collapsed++; 2579ce83d217SAndrea Arcangeli out_up_write: 2580ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 25810bbbc0b3SAndrea Arcangeli return; 25820bbbc0b3SAndrea Arcangeli 2583ce83d217SAndrea Arcangeli out: 258400501b53SJohannes Weiner mem_cgroup_cancel_charge(new_page, memcg); 2585ce83d217SAndrea Arcangeli goto out_up_write; 2586ba76149fSAndrea Arcangeli } 2587ba76149fSAndrea Arcangeli 2588ba76149fSAndrea Arcangeli static int khugepaged_scan_pmd(struct mm_struct *mm, 2589ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 2590ba76149fSAndrea Arcangeli unsigned long address, 2591ba76149fSAndrea Arcangeli struct page **hpage) 2592ba76149fSAndrea Arcangeli { 2593ba76149fSAndrea Arcangeli pmd_t *pmd; 2594ba76149fSAndrea Arcangeli pte_t *pte, *_pte; 2595ca0984caSEbru Akagunduz int ret = 0, none_or_zero = 0; 2596ba76149fSAndrea Arcangeli struct page *page; 2597ba76149fSAndrea Arcangeli unsigned long _address; 2598ba76149fSAndrea Arcangeli spinlock_t *ptl; 259900ef2d2fSDavid Rientjes int node = NUMA_NO_NODE; 260010359213SEbru Akagunduz bool writable = false, referenced = false; 2601ba76149fSAndrea Arcangeli 2602ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 2603ba76149fSAndrea Arcangeli 26046219049aSBob Liu pmd = mm_find_pmd(mm, address); 26056219049aSBob Liu if (!pmd) 2606ba76149fSAndrea Arcangeli goto out; 2607ba76149fSAndrea Arcangeli 26089f1b868aSBob Liu memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load)); 2609ba76149fSAndrea Arcangeli pte = pte_offset_map_lock(mm, pmd, address, &ptl); 2610ba76149fSAndrea Arcangeli for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; 2611ba76149fSAndrea Arcangeli _pte++, _address += PAGE_SIZE) { 2612ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2613ca0984caSEbru Akagunduz if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { 2614ca0984caSEbru Akagunduz if (++none_or_zero <= khugepaged_max_ptes_none) 2615ba76149fSAndrea Arcangeli continue; 2616ba76149fSAndrea Arcangeli else 2617ba76149fSAndrea Arcangeli goto out_unmap; 2618ba76149fSAndrea Arcangeli } 261910359213SEbru Akagunduz if (!pte_present(pteval)) 2620ba76149fSAndrea Arcangeli goto out_unmap; 262110359213SEbru Akagunduz if (pte_write(pteval)) 262210359213SEbru Akagunduz writable = true; 262310359213SEbru Akagunduz 2624ba76149fSAndrea Arcangeli page = vm_normal_page(vma, _address, pteval); 2625ba76149fSAndrea Arcangeli if (unlikely(!page)) 2626ba76149fSAndrea Arcangeli goto out_unmap; 26275c4b4be3SAndi Kleen /* 26289f1b868aSBob Liu * Record which node the original page is from and save this 26299f1b868aSBob Liu * information to khugepaged_node_load[]. 26309f1b868aSBob Liu * Khupaged will allocate hugepage from the node has the max 26319f1b868aSBob Liu * hit record. 26325c4b4be3SAndi Kleen */ 26335c4b4be3SAndi Kleen node = page_to_nid(page); 263414a4e214SDavid Rientjes if (khugepaged_scan_abort(node)) 263514a4e214SDavid Rientjes goto out_unmap; 26369f1b868aSBob Liu khugepaged_node_load[node]++; 2637309381feSSasha Levin VM_BUG_ON_PAGE(PageCompound(page), page); 2638ba76149fSAndrea Arcangeli if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) 2639ba76149fSAndrea Arcangeli goto out_unmap; 264010359213SEbru Akagunduz /* 264110359213SEbru Akagunduz * cannot use mapcount: can't collapse if there's a gup pin. 264210359213SEbru Akagunduz * The page must only be referenced by the scanned process 264310359213SEbru Akagunduz * and page swap cache. 264410359213SEbru Akagunduz */ 264510359213SEbru Akagunduz if (page_count(page) != 1 + !!PageSwapCache(page)) 2646ba76149fSAndrea Arcangeli goto out_unmap; 26478ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 26488ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 264910359213SEbru Akagunduz referenced = true; 2650ba76149fSAndrea Arcangeli } 265110359213SEbru Akagunduz if (referenced && writable) 2652ba76149fSAndrea Arcangeli ret = 1; 2653ba76149fSAndrea Arcangeli out_unmap: 2654ba76149fSAndrea Arcangeli pte_unmap_unlock(pte, ptl); 26559f1b868aSBob Liu if (ret) { 26569f1b868aSBob Liu node = khugepaged_find_target_node(); 2657ce83d217SAndrea Arcangeli /* collapse_huge_page will return with the mmap_sem released */ 26585c4b4be3SAndi Kleen collapse_huge_page(mm, address, hpage, vma, node); 26599f1b868aSBob Liu } 2660ba76149fSAndrea Arcangeli out: 2661ba76149fSAndrea Arcangeli return ret; 2662ba76149fSAndrea Arcangeli } 2663ba76149fSAndrea Arcangeli 2664ba76149fSAndrea Arcangeli static void collect_mm_slot(struct mm_slot *mm_slot) 2665ba76149fSAndrea Arcangeli { 2666ba76149fSAndrea Arcangeli struct mm_struct *mm = mm_slot->mm; 2667ba76149fSAndrea Arcangeli 2668b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2669ba76149fSAndrea Arcangeli 2670ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm)) { 2671ba76149fSAndrea Arcangeli /* free mm_slot */ 267243b5fbbdSSasha Levin hash_del(&mm_slot->hash); 2673ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 2674ba76149fSAndrea Arcangeli 2675ba76149fSAndrea Arcangeli /* 2676ba76149fSAndrea Arcangeli * Not strictly needed because the mm exited already. 2677ba76149fSAndrea Arcangeli * 2678ba76149fSAndrea Arcangeli * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 2679ba76149fSAndrea Arcangeli */ 2680ba76149fSAndrea Arcangeli 2681ba76149fSAndrea Arcangeli /* khugepaged_mm_lock actually not necessary for the below */ 2682ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2683ba76149fSAndrea Arcangeli mmdrop(mm); 2684ba76149fSAndrea Arcangeli } 2685ba76149fSAndrea Arcangeli } 2686ba76149fSAndrea Arcangeli 2687ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_mm_slot(unsigned int pages, 2688ba76149fSAndrea Arcangeli struct page **hpage) 26892f1da642SH Hartley Sweeten __releases(&khugepaged_mm_lock) 26902f1da642SH Hartley Sweeten __acquires(&khugepaged_mm_lock) 2691ba76149fSAndrea Arcangeli { 2692ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2693ba76149fSAndrea Arcangeli struct mm_struct *mm; 2694ba76149fSAndrea Arcangeli struct vm_area_struct *vma; 2695ba76149fSAndrea Arcangeli int progress = 0; 2696ba76149fSAndrea Arcangeli 2697ba76149fSAndrea Arcangeli VM_BUG_ON(!pages); 2698b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2699ba76149fSAndrea Arcangeli 2700ba76149fSAndrea Arcangeli if (khugepaged_scan.mm_slot) 2701ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2702ba76149fSAndrea Arcangeli else { 2703ba76149fSAndrea Arcangeli mm_slot = list_entry(khugepaged_scan.mm_head.next, 2704ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2705ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2706ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = mm_slot; 2707ba76149fSAndrea Arcangeli } 2708ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2709ba76149fSAndrea Arcangeli 2710ba76149fSAndrea Arcangeli mm = mm_slot->mm; 2711ba76149fSAndrea Arcangeli down_read(&mm->mmap_sem); 2712ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2713ba76149fSAndrea Arcangeli vma = NULL; 2714ba76149fSAndrea Arcangeli else 2715ba76149fSAndrea Arcangeli vma = find_vma(mm, khugepaged_scan.address); 2716ba76149fSAndrea Arcangeli 2717ba76149fSAndrea Arcangeli progress++; 2718ba76149fSAndrea Arcangeli for (; vma; vma = vma->vm_next) { 2719ba76149fSAndrea Arcangeli unsigned long hstart, hend; 2720ba76149fSAndrea Arcangeli 2721ba76149fSAndrea Arcangeli cond_resched(); 2722ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) { 2723ba76149fSAndrea Arcangeli progress++; 2724ba76149fSAndrea Arcangeli break; 2725ba76149fSAndrea Arcangeli } 2726fa475e51SBob Liu if (!hugepage_vma_check(vma)) { 2727a7d6e4ecSAndrea Arcangeli skip: 2728ba76149fSAndrea Arcangeli progress++; 2729ba76149fSAndrea Arcangeli continue; 2730ba76149fSAndrea Arcangeli } 2731ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2732ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2733a7d6e4ecSAndrea Arcangeli if (hstart >= hend) 2734a7d6e4ecSAndrea Arcangeli goto skip; 2735a7d6e4ecSAndrea Arcangeli if (khugepaged_scan.address > hend) 2736a7d6e4ecSAndrea Arcangeli goto skip; 2737ba76149fSAndrea Arcangeli if (khugepaged_scan.address < hstart) 2738ba76149fSAndrea Arcangeli khugepaged_scan.address = hstart; 2739a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); 2740ba76149fSAndrea Arcangeli 2741ba76149fSAndrea Arcangeli while (khugepaged_scan.address < hend) { 2742ba76149fSAndrea Arcangeli int ret; 2743ba76149fSAndrea Arcangeli cond_resched(); 2744ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2745ba76149fSAndrea Arcangeli goto breakouterloop; 2746ba76149fSAndrea Arcangeli 2747ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address < hstart || 2748ba76149fSAndrea Arcangeli khugepaged_scan.address + HPAGE_PMD_SIZE > 2749ba76149fSAndrea Arcangeli hend); 2750ba76149fSAndrea Arcangeli ret = khugepaged_scan_pmd(mm, vma, 2751ba76149fSAndrea Arcangeli khugepaged_scan.address, 2752ba76149fSAndrea Arcangeli hpage); 2753ba76149fSAndrea Arcangeli /* move to next address */ 2754ba76149fSAndrea Arcangeli khugepaged_scan.address += HPAGE_PMD_SIZE; 2755ba76149fSAndrea Arcangeli progress += HPAGE_PMD_NR; 2756ba76149fSAndrea Arcangeli if (ret) 2757ba76149fSAndrea Arcangeli /* we released mmap_sem so break loop */ 2758ba76149fSAndrea Arcangeli goto breakouterloop_mmap_sem; 2759ba76149fSAndrea Arcangeli if (progress >= pages) 2760ba76149fSAndrea Arcangeli goto breakouterloop; 2761ba76149fSAndrea Arcangeli } 2762ba76149fSAndrea Arcangeli } 2763ba76149fSAndrea Arcangeli breakouterloop: 2764ba76149fSAndrea Arcangeli up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ 2765ba76149fSAndrea Arcangeli breakouterloop_mmap_sem: 2766ba76149fSAndrea Arcangeli 2767ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2768a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); 2769ba76149fSAndrea Arcangeli /* 2770ba76149fSAndrea Arcangeli * Release the current mm_slot if this mm is about to die, or 2771ba76149fSAndrea Arcangeli * if we scanned all vmas of this mm. 2772ba76149fSAndrea Arcangeli */ 2773ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm) || !vma) { 2774ba76149fSAndrea Arcangeli /* 2775ba76149fSAndrea Arcangeli * Make sure that if mm_users is reaching zero while 2776ba76149fSAndrea Arcangeli * khugepaged runs here, khugepaged_exit will find 2777ba76149fSAndrea Arcangeli * mm_slot not pointing to the exiting mm. 2778ba76149fSAndrea Arcangeli */ 2779ba76149fSAndrea Arcangeli if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { 2780ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = list_entry( 2781ba76149fSAndrea Arcangeli mm_slot->mm_node.next, 2782ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2783ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2784ba76149fSAndrea Arcangeli } else { 2785ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2786ba76149fSAndrea Arcangeli khugepaged_full_scans++; 2787ba76149fSAndrea Arcangeli } 2788ba76149fSAndrea Arcangeli 2789ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2790ba76149fSAndrea Arcangeli } 2791ba76149fSAndrea Arcangeli 2792ba76149fSAndrea Arcangeli return progress; 2793ba76149fSAndrea Arcangeli } 2794ba76149fSAndrea Arcangeli 2795ba76149fSAndrea Arcangeli static int khugepaged_has_work(void) 2796ba76149fSAndrea Arcangeli { 2797ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) && 2798ba76149fSAndrea Arcangeli khugepaged_enabled(); 2799ba76149fSAndrea Arcangeli } 2800ba76149fSAndrea Arcangeli 2801ba76149fSAndrea Arcangeli static int khugepaged_wait_event(void) 2802ba76149fSAndrea Arcangeli { 2803ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) || 28042017c0bfSXiao Guangrong kthread_should_stop(); 2805ba76149fSAndrea Arcangeli } 2806ba76149fSAndrea Arcangeli 2807d516904bSXiao Guangrong static void khugepaged_do_scan(void) 2808d516904bSXiao Guangrong { 2809d516904bSXiao Guangrong struct page *hpage = NULL; 2810ba76149fSAndrea Arcangeli unsigned int progress = 0, pass_through_head = 0; 2811ba76149fSAndrea Arcangeli unsigned int pages = khugepaged_pages_to_scan; 2812d516904bSXiao Guangrong bool wait = true; 2813ba76149fSAndrea Arcangeli 2814ba76149fSAndrea Arcangeli barrier(); /* write khugepaged_pages_to_scan to local stack */ 2815ba76149fSAndrea Arcangeli 2816ba76149fSAndrea Arcangeli while (progress < pages) { 281726234f36SXiao Guangrong if (!khugepaged_prealloc_page(&hpage, &wait)) 281826234f36SXiao Guangrong break; 2819d516904bSXiao Guangrong 2820420256efSXiao Guangrong cond_resched(); 2821ba76149fSAndrea Arcangeli 2822cd092411SJiri Kosina if (unlikely(kthread_should_stop() || try_to_freeze())) 2823878aee7dSAndrea Arcangeli break; 2824878aee7dSAndrea Arcangeli 2825ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2826ba76149fSAndrea Arcangeli if (!khugepaged_scan.mm_slot) 2827ba76149fSAndrea Arcangeli pass_through_head++; 2828ba76149fSAndrea Arcangeli if (khugepaged_has_work() && 2829ba76149fSAndrea Arcangeli pass_through_head < 2) 2830ba76149fSAndrea Arcangeli progress += khugepaged_scan_mm_slot(pages - progress, 2831d516904bSXiao Guangrong &hpage); 2832ba76149fSAndrea Arcangeli else 2833ba76149fSAndrea Arcangeli progress = pages; 2834ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2835ba76149fSAndrea Arcangeli } 2836ba76149fSAndrea Arcangeli 2837d516904bSXiao Guangrong if (!IS_ERR_OR_NULL(hpage)) 2838d516904bSXiao Guangrong put_page(hpage); 2839ba76149fSAndrea Arcangeli } 28400bbbc0b3SAndrea Arcangeli 28412017c0bfSXiao Guangrong static void khugepaged_wait_work(void) 28422017c0bfSXiao Guangrong { 28432017c0bfSXiao Guangrong if (khugepaged_has_work()) { 28442017c0bfSXiao Guangrong if (!khugepaged_scan_sleep_millisecs) 28452017c0bfSXiao Guangrong return; 28462017c0bfSXiao Guangrong 28472017c0bfSXiao Guangrong wait_event_freezable_timeout(khugepaged_wait, 28482017c0bfSXiao Guangrong kthread_should_stop(), 28492017c0bfSXiao Guangrong msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); 28502017c0bfSXiao Guangrong return; 28512017c0bfSXiao Guangrong } 28522017c0bfSXiao Guangrong 28532017c0bfSXiao Guangrong if (khugepaged_enabled()) 28542017c0bfSXiao Guangrong wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); 28552017c0bfSXiao Guangrong } 28562017c0bfSXiao Guangrong 2857ba76149fSAndrea Arcangeli static int khugepaged(void *none) 2858ba76149fSAndrea Arcangeli { 2859ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2860ba76149fSAndrea Arcangeli 2861878aee7dSAndrea Arcangeli set_freezable(); 28628698a745SDongsheng Yang set_user_nice(current, MAX_NICE); 2863ba76149fSAndrea Arcangeli 2864b7231789SXiao Guangrong while (!kthread_should_stop()) { 2865b7231789SXiao Guangrong khugepaged_do_scan(); 2866b7231789SXiao Guangrong khugepaged_wait_work(); 2867b7231789SXiao Guangrong } 2868ba76149fSAndrea Arcangeli 2869ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2870ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2871ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2872ba76149fSAndrea Arcangeli if (mm_slot) 2873ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2874ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2875ba76149fSAndrea Arcangeli return 0; 2876ba76149fSAndrea Arcangeli } 2877ba76149fSAndrea Arcangeli 2878c5a647d0SKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2879c5a647d0SKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2880c5a647d0SKirill A. Shutemov { 2881c5a647d0SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2882c5a647d0SKirill A. Shutemov pgtable_t pgtable; 2883c5a647d0SKirill A. Shutemov pmd_t _pmd; 2884c5a647d0SKirill A. Shutemov int i; 2885c5a647d0SKirill A. Shutemov 28868809aa2dSAneesh Kumar K.V pmdp_huge_clear_flush_notify(vma, haddr, pmd); 2887c5a647d0SKirill A. Shutemov /* leave pmd empty until pte is filled */ 2888c5a647d0SKirill A. Shutemov 28896b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2890c5a647d0SKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2891c5a647d0SKirill A. Shutemov 2892c5a647d0SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 2893c5a647d0SKirill A. Shutemov pte_t *pte, entry; 2894c5a647d0SKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 2895c5a647d0SKirill A. Shutemov entry = pte_mkspecial(entry); 2896c5a647d0SKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 2897c5a647d0SKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 2898c5a647d0SKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 2899c5a647d0SKirill A. Shutemov pte_unmap(pte); 2900c5a647d0SKirill A. Shutemov } 2901c5a647d0SKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2902c5a647d0SKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 290397ae1749SKirill A. Shutemov put_huge_zero_page(); 2904c5a647d0SKirill A. Shutemov } 2905c5a647d0SKirill A. Shutemov 2906e180377fSKirill A. Shutemov void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, 2907e180377fSKirill A. Shutemov pmd_t *pmd) 290871e3aac0SAndrea Arcangeli { 2909c4088ebdSKirill A. Shutemov spinlock_t *ptl; 291071e3aac0SAndrea Arcangeli struct page *page; 2911e180377fSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2912c5a647d0SKirill A. Shutemov unsigned long haddr = address & HPAGE_PMD_MASK; 2913c5a647d0SKirill A. Shutemov unsigned long mmun_start; /* For mmu_notifiers */ 2914c5a647d0SKirill A. Shutemov unsigned long mmun_end; /* For mmu_notifiers */ 2915e180377fSKirill A. Shutemov 2916e180377fSKirill A. Shutemov BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); 291771e3aac0SAndrea Arcangeli 2918c5a647d0SKirill A. Shutemov mmun_start = haddr; 2919c5a647d0SKirill A. Shutemov mmun_end = haddr + HPAGE_PMD_SIZE; 2920750e8165SHugh Dickins again: 2921c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2922c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 292371e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(*pmd))) { 2924c4088ebdSKirill A. Shutemov spin_unlock(ptl); 2925c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2926c5a647d0SKirill A. Shutemov return; 2927c5a647d0SKirill A. Shutemov } 2928c5a647d0SKirill A. Shutemov if (is_huge_zero_pmd(*pmd)) { 2929c5a647d0SKirill A. Shutemov __split_huge_zero_page_pmd(vma, haddr, pmd); 2930c4088ebdSKirill A. Shutemov spin_unlock(ptl); 2931c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 293271e3aac0SAndrea Arcangeli return; 293371e3aac0SAndrea Arcangeli } 293471e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 2935309381feSSasha Levin VM_BUG_ON_PAGE(!page_count(page), page); 293671e3aac0SAndrea Arcangeli get_page(page); 2937c4088ebdSKirill A. Shutemov spin_unlock(ptl); 2938c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 293971e3aac0SAndrea Arcangeli 294071e3aac0SAndrea Arcangeli split_huge_page(page); 294171e3aac0SAndrea Arcangeli 294271e3aac0SAndrea Arcangeli put_page(page); 2943750e8165SHugh Dickins 2944750e8165SHugh Dickins /* 2945750e8165SHugh Dickins * We don't always have down_write of mmap_sem here: a racing 2946750e8165SHugh Dickins * do_huge_pmd_wp_page() might have copied-on-write to another 2947750e8165SHugh Dickins * huge page before our split_huge_page() got the anon_vma lock. 2948750e8165SHugh Dickins */ 2949750e8165SHugh Dickins if (unlikely(pmd_trans_huge(*pmd))) 2950750e8165SHugh Dickins goto again; 295171e3aac0SAndrea Arcangeli } 295294fcc585SAndrea Arcangeli 2953e180377fSKirill A. Shutemov void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, 2954e180377fSKirill A. Shutemov pmd_t *pmd) 2955e180377fSKirill A. Shutemov { 2956e180377fSKirill A. Shutemov struct vm_area_struct *vma; 2957e180377fSKirill A. Shutemov 2958e180377fSKirill A. Shutemov vma = find_vma(mm, address); 2959e180377fSKirill A. Shutemov BUG_ON(vma == NULL); 2960e180377fSKirill A. Shutemov split_huge_page_pmd(vma, address, pmd); 2961e180377fSKirill A. Shutemov } 2962e180377fSKirill A. Shutemov 296394fcc585SAndrea Arcangeli static void split_huge_page_address(struct mm_struct *mm, 296494fcc585SAndrea Arcangeli unsigned long address) 296594fcc585SAndrea Arcangeli { 2966f72e7dcdSHugh Dickins pgd_t *pgd; 2967f72e7dcdSHugh Dickins pud_t *pud; 296894fcc585SAndrea Arcangeli pmd_t *pmd; 296994fcc585SAndrea Arcangeli 297094fcc585SAndrea Arcangeli VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); 297194fcc585SAndrea Arcangeli 2972f72e7dcdSHugh Dickins pgd = pgd_offset(mm, address); 2973f72e7dcdSHugh Dickins if (!pgd_present(*pgd)) 2974f72e7dcdSHugh Dickins return; 2975f72e7dcdSHugh Dickins 2976f72e7dcdSHugh Dickins pud = pud_offset(pgd, address); 2977f72e7dcdSHugh Dickins if (!pud_present(*pud)) 2978f72e7dcdSHugh Dickins return; 2979f72e7dcdSHugh Dickins 2980f72e7dcdSHugh Dickins pmd = pmd_offset(pud, address); 2981f72e7dcdSHugh Dickins if (!pmd_present(*pmd)) 298294fcc585SAndrea Arcangeli return; 298394fcc585SAndrea Arcangeli /* 298494fcc585SAndrea Arcangeli * Caller holds the mmap_sem write mode, so a huge pmd cannot 298594fcc585SAndrea Arcangeli * materialize from under us. 298694fcc585SAndrea Arcangeli */ 2987e180377fSKirill A. Shutemov split_huge_page_pmd_mm(mm, address, pmd); 298894fcc585SAndrea Arcangeli } 298994fcc585SAndrea Arcangeli 299094fcc585SAndrea Arcangeli void __vma_adjust_trans_huge(struct vm_area_struct *vma, 299194fcc585SAndrea Arcangeli unsigned long start, 299294fcc585SAndrea Arcangeli unsigned long end, 299394fcc585SAndrea Arcangeli long adjust_next) 299494fcc585SAndrea Arcangeli { 299594fcc585SAndrea Arcangeli /* 299694fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 299794fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 299894fcc585SAndrea Arcangeli * an huge pmd. 299994fcc585SAndrea Arcangeli */ 300094fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 300194fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 300294fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 300394fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, start); 300494fcc585SAndrea Arcangeli 300594fcc585SAndrea Arcangeli /* 300694fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 300794fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 300894fcc585SAndrea Arcangeli * an huge pmd. 300994fcc585SAndrea Arcangeli */ 301094fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 301194fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 301294fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 301394fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, end); 301494fcc585SAndrea Arcangeli 301594fcc585SAndrea Arcangeli /* 301694fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 301794fcc585SAndrea Arcangeli * vm_next->vm_start isn't page aligned and it could previously 301894fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 301994fcc585SAndrea Arcangeli */ 302094fcc585SAndrea Arcangeli if (adjust_next > 0) { 302194fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 302294fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 302394fcc585SAndrea Arcangeli nstart += adjust_next << PAGE_SHIFT; 302494fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 302594fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 302694fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 302794fcc585SAndrea Arcangeli split_huge_page_address(next->vm_mm, nstart); 302894fcc585SAndrea Arcangeli } 302994fcc585SAndrea Arcangeli } 3030