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 871e3aac0SAndrea Arcangeli #include <linux/mm.h> 971e3aac0SAndrea Arcangeli #include <linux/sched.h> 1071e3aac0SAndrea Arcangeli #include <linux/highmem.h> 1171e3aac0SAndrea Arcangeli #include <linux/hugetlb.h> 1271e3aac0SAndrea Arcangeli #include <linux/mmu_notifier.h> 1371e3aac0SAndrea Arcangeli #include <linux/rmap.h> 1471e3aac0SAndrea Arcangeli #include <linux/swap.h> 1597ae1749SKirill A. Shutemov #include <linux/shrinker.h> 16ba76149fSAndrea Arcangeli #include <linux/mm_inline.h> 17ba76149fSAndrea Arcangeli #include <linux/kthread.h> 18ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 19878aee7dSAndrea Arcangeli #include <linux/freezer.h> 20a664b2d8SAndrea Arcangeli #include <linux/mman.h> 21325adeb5SRalf Baechle #include <linux/pagemap.h> 224daae3b4SMel Gorman #include <linux/migrate.h> 2343b5fbbdSSasha Levin #include <linux/hashtable.h> 2497ae1749SKirill A. Shutemov 2571e3aac0SAndrea Arcangeli #include <asm/tlb.h> 2671e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 2771e3aac0SAndrea Arcangeli #include "internal.h" 2871e3aac0SAndrea Arcangeli 29ba76149fSAndrea Arcangeli /* 30ba76149fSAndrea Arcangeli * By default transparent hugepage support is enabled for all mappings 31ba76149fSAndrea Arcangeli * and khugepaged scans all mappings. Defrag is only invoked by 32ba76149fSAndrea Arcangeli * khugepaged hugepage allocations and by page faults inside 33ba76149fSAndrea Arcangeli * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived 34ba76149fSAndrea Arcangeli * allocations. 35ba76149fSAndrea Arcangeli */ 3671e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 3713ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 38ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 3913ece886SAndrea Arcangeli #endif 4013ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 4113ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 4213ece886SAndrea Arcangeli #endif 43d39d33c3SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| 4479da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 4579da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 46ba76149fSAndrea Arcangeli 47ba76149fSAndrea Arcangeli /* default scan 8*512 pte (or vmas) every 30 second */ 48ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; 49ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_collapsed; 50ba76149fSAndrea Arcangeli static unsigned int khugepaged_full_scans; 51ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; 52ba76149fSAndrea Arcangeli /* during fragmentation poll the hugepage allocator once every minute */ 53ba76149fSAndrea Arcangeli static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; 54ba76149fSAndrea Arcangeli static struct task_struct *khugepaged_thread __read_mostly; 55ba76149fSAndrea Arcangeli static DEFINE_MUTEX(khugepaged_mutex); 56ba76149fSAndrea Arcangeli static DEFINE_SPINLOCK(khugepaged_mm_lock); 57ba76149fSAndrea Arcangeli static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); 58ba76149fSAndrea Arcangeli /* 59ba76149fSAndrea Arcangeli * default collapse hugepages if there is at least one pte mapped like 60ba76149fSAndrea Arcangeli * it would have happened if the vma was large enough during page 61ba76149fSAndrea Arcangeli * fault. 62ba76149fSAndrea Arcangeli */ 63ba76149fSAndrea Arcangeli static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; 64ba76149fSAndrea Arcangeli 65ba76149fSAndrea Arcangeli static int khugepaged(void *none); 66ba76149fSAndrea Arcangeli static int khugepaged_slab_init(void); 67ba76149fSAndrea Arcangeli 6843b5fbbdSSasha Levin #define MM_SLOTS_HASH_BITS 10 6943b5fbbdSSasha Levin static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); 7043b5fbbdSSasha Levin 71ba76149fSAndrea Arcangeli static struct kmem_cache *mm_slot_cache __read_mostly; 72ba76149fSAndrea Arcangeli 73ba76149fSAndrea Arcangeli /** 74ba76149fSAndrea Arcangeli * struct mm_slot - hash lookup from mm to mm_slot 75ba76149fSAndrea Arcangeli * @hash: hash collision list 76ba76149fSAndrea Arcangeli * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head 77ba76149fSAndrea Arcangeli * @mm: the mm that this information is valid for 78ba76149fSAndrea Arcangeli */ 79ba76149fSAndrea Arcangeli struct mm_slot { 80ba76149fSAndrea Arcangeli struct hlist_node hash; 81ba76149fSAndrea Arcangeli struct list_head mm_node; 82ba76149fSAndrea Arcangeli struct mm_struct *mm; 83ba76149fSAndrea Arcangeli }; 84ba76149fSAndrea Arcangeli 85ba76149fSAndrea Arcangeli /** 86ba76149fSAndrea Arcangeli * struct khugepaged_scan - cursor for scanning 87ba76149fSAndrea Arcangeli * @mm_head: the head of the mm list to scan 88ba76149fSAndrea Arcangeli * @mm_slot: the current mm_slot we are scanning 89ba76149fSAndrea Arcangeli * @address: the next address inside that to be scanned 90ba76149fSAndrea Arcangeli * 91ba76149fSAndrea Arcangeli * There is only the one khugepaged_scan instance of this cursor structure. 92ba76149fSAndrea Arcangeli */ 93ba76149fSAndrea Arcangeli struct khugepaged_scan { 94ba76149fSAndrea Arcangeli struct list_head mm_head; 95ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 96ba76149fSAndrea Arcangeli unsigned long address; 972f1da642SH Hartley Sweeten }; 982f1da642SH Hartley Sweeten static struct khugepaged_scan khugepaged_scan = { 99ba76149fSAndrea Arcangeli .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), 100ba76149fSAndrea Arcangeli }; 101ba76149fSAndrea Arcangeli 102f000565aSAndrea Arcangeli 103f000565aSAndrea Arcangeli static int set_recommended_min_free_kbytes(void) 104f000565aSAndrea Arcangeli { 105f000565aSAndrea Arcangeli struct zone *zone; 106f000565aSAndrea Arcangeli int nr_zones = 0; 107f000565aSAndrea Arcangeli unsigned long recommended_min; 108f000565aSAndrea Arcangeli 10917c230afSXiao Guangrong if (!khugepaged_enabled()) 110f000565aSAndrea Arcangeli return 0; 111f000565aSAndrea Arcangeli 112f000565aSAndrea Arcangeli for_each_populated_zone(zone) 113f000565aSAndrea Arcangeli nr_zones++; 114f000565aSAndrea Arcangeli 115f000565aSAndrea Arcangeli /* Make sure at least 2 hugepages are free for MIGRATE_RESERVE */ 116f000565aSAndrea Arcangeli recommended_min = pageblock_nr_pages * nr_zones * 2; 117f000565aSAndrea Arcangeli 118f000565aSAndrea Arcangeli /* 119f000565aSAndrea Arcangeli * Make sure that on average at least two pageblocks are almost free 120f000565aSAndrea Arcangeli * of another type, one for a migratetype to fall back to and a 121f000565aSAndrea Arcangeli * second to avoid subsequent fallbacks of other types There are 3 122f000565aSAndrea Arcangeli * MIGRATE_TYPES we care about. 123f000565aSAndrea Arcangeli */ 124f000565aSAndrea Arcangeli recommended_min += pageblock_nr_pages * nr_zones * 125f000565aSAndrea Arcangeli MIGRATE_PCPTYPES * MIGRATE_PCPTYPES; 126f000565aSAndrea Arcangeli 127f000565aSAndrea Arcangeli /* don't ever allow to reserve more than 5% of the lowmem */ 128f000565aSAndrea Arcangeli recommended_min = min(recommended_min, 129f000565aSAndrea Arcangeli (unsigned long) nr_free_buffer_pages() / 20); 130f000565aSAndrea Arcangeli recommended_min <<= (PAGE_SHIFT-10); 131f000565aSAndrea Arcangeli 132f000565aSAndrea Arcangeli if (recommended_min > min_free_kbytes) 133f000565aSAndrea Arcangeli min_free_kbytes = recommended_min; 134f000565aSAndrea Arcangeli setup_per_zone_wmarks(); 135f000565aSAndrea Arcangeli return 0; 136f000565aSAndrea Arcangeli } 137f000565aSAndrea Arcangeli late_initcall(set_recommended_min_free_kbytes); 138f000565aSAndrea Arcangeli 139ba76149fSAndrea Arcangeli static int start_khugepaged(void) 140ba76149fSAndrea Arcangeli { 141ba76149fSAndrea Arcangeli int err = 0; 142ba76149fSAndrea Arcangeli if (khugepaged_enabled()) { 143ba76149fSAndrea Arcangeli if (!khugepaged_thread) 144ba76149fSAndrea Arcangeli khugepaged_thread = kthread_run(khugepaged, NULL, 145ba76149fSAndrea Arcangeli "khugepaged"); 146ba76149fSAndrea Arcangeli if (unlikely(IS_ERR(khugepaged_thread))) { 147ba76149fSAndrea Arcangeli printk(KERN_ERR 148ba76149fSAndrea Arcangeli "khugepaged: kthread_run(khugepaged) failed\n"); 149ba76149fSAndrea Arcangeli err = PTR_ERR(khugepaged_thread); 150ba76149fSAndrea Arcangeli khugepaged_thread = NULL; 151ba76149fSAndrea Arcangeli } 152911891afSXiao Guangrong 153911891afSXiao Guangrong if (!list_empty(&khugepaged_scan.mm_head)) 154ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 155f000565aSAndrea Arcangeli 156f000565aSAndrea Arcangeli set_recommended_min_free_kbytes(); 157911891afSXiao Guangrong } else if (khugepaged_thread) { 158911891afSXiao Guangrong kthread_stop(khugepaged_thread); 159911891afSXiao Guangrong khugepaged_thread = NULL; 160911891afSXiao Guangrong } 161637e3a27SXiao Guangrong 162ba76149fSAndrea Arcangeli return err; 163ba76149fSAndrea Arcangeli } 16471e3aac0SAndrea Arcangeli 16597ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 1665918d10aSKirill A. Shutemov static struct page *huge_zero_page __read_mostly; 1674a6c1297SKirill A. Shutemov 1685918d10aSKirill A. Shutemov static inline bool is_huge_zero_page(struct page *page) 1694a6c1297SKirill A. Shutemov { 1705918d10aSKirill A. Shutemov return ACCESS_ONCE(huge_zero_page) == page; 1714a6c1297SKirill A. Shutemov } 1724a6c1297SKirill A. Shutemov 1734a6c1297SKirill A. Shutemov static inline bool is_huge_zero_pmd(pmd_t pmd) 1744a6c1297SKirill A. Shutemov { 1755918d10aSKirill A. Shutemov return is_huge_zero_page(pmd_page(pmd)); 1764a6c1297SKirill A. Shutemov } 1774a6c1297SKirill A. Shutemov 1785918d10aSKirill A. Shutemov static struct page *get_huge_zero_page(void) 17997ae1749SKirill A. Shutemov { 18097ae1749SKirill A. Shutemov struct page *zero_page; 18197ae1749SKirill A. Shutemov retry: 18297ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 1835918d10aSKirill A. Shutemov return ACCESS_ONCE(huge_zero_page); 18497ae1749SKirill A. Shutemov 18597ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 18697ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 187d8a8e1f0SKirill A. Shutemov if (!zero_page) { 188d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 1895918d10aSKirill A. Shutemov return NULL; 190d8a8e1f0SKirill A. Shutemov } 191d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC); 19297ae1749SKirill A. Shutemov preempt_disable(); 1935918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 19497ae1749SKirill A. Shutemov preempt_enable(); 19597ae1749SKirill A. Shutemov __free_page(zero_page); 19697ae1749SKirill A. Shutemov goto retry; 19797ae1749SKirill A. Shutemov } 19897ae1749SKirill A. Shutemov 19997ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 20097ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 20197ae1749SKirill A. Shutemov preempt_enable(); 2025918d10aSKirill A. Shutemov return ACCESS_ONCE(huge_zero_page); 20397ae1749SKirill A. Shutemov } 20497ae1749SKirill A. Shutemov 20597ae1749SKirill A. Shutemov static void put_huge_zero_page(void) 20697ae1749SKirill A. Shutemov { 20797ae1749SKirill A. Shutemov /* 20897ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 20997ae1749SKirill A. Shutemov * last reference. 21097ae1749SKirill A. Shutemov */ 21197ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 21297ae1749SKirill A. Shutemov } 21397ae1749SKirill A. Shutemov 21497ae1749SKirill A. Shutemov static int shrink_huge_zero_page(struct shrinker *shrink, 21597ae1749SKirill A. Shutemov struct shrink_control *sc) 21697ae1749SKirill A. Shutemov { 21797ae1749SKirill A. Shutemov if (!sc->nr_to_scan) 21897ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 21997ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 22097ae1749SKirill A. Shutemov 22197ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2225918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2235918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2245918d10aSKirill A. Shutemov __free_page(zero_page); 22597ae1749SKirill A. Shutemov } 22697ae1749SKirill A. Shutemov 22797ae1749SKirill A. Shutemov return 0; 22897ae1749SKirill A. Shutemov } 22997ae1749SKirill A. Shutemov 23097ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 23197ae1749SKirill A. Shutemov .shrink = shrink_huge_zero_page, 23297ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 23397ae1749SKirill A. Shutemov }; 23497ae1749SKirill A. Shutemov 23571e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 236ba76149fSAndrea Arcangeli 23771e3aac0SAndrea Arcangeli static ssize_t double_flag_show(struct kobject *kobj, 23871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 23971e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 24071e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 24171e3aac0SAndrea Arcangeli { 24271e3aac0SAndrea Arcangeli if (test_bit(enabled, &transparent_hugepage_flags)) { 24371e3aac0SAndrea Arcangeli VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); 24471e3aac0SAndrea Arcangeli return sprintf(buf, "[always] madvise never\n"); 24571e3aac0SAndrea Arcangeli } else if (test_bit(req_madv, &transparent_hugepage_flags)) 24671e3aac0SAndrea Arcangeli return sprintf(buf, "always [madvise] never\n"); 24771e3aac0SAndrea Arcangeli else 24871e3aac0SAndrea Arcangeli return sprintf(buf, "always madvise [never]\n"); 24971e3aac0SAndrea Arcangeli } 25071e3aac0SAndrea Arcangeli static ssize_t double_flag_store(struct kobject *kobj, 25171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 25271e3aac0SAndrea Arcangeli const char *buf, size_t count, 25371e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 25471e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 25571e3aac0SAndrea Arcangeli { 25671e3aac0SAndrea Arcangeli if (!memcmp("always", buf, 25771e3aac0SAndrea Arcangeli min(sizeof("always")-1, count))) { 25871e3aac0SAndrea Arcangeli set_bit(enabled, &transparent_hugepage_flags); 25971e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 26071e3aac0SAndrea Arcangeli } else if (!memcmp("madvise", buf, 26171e3aac0SAndrea Arcangeli min(sizeof("madvise")-1, count))) { 26271e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 26371e3aac0SAndrea Arcangeli set_bit(req_madv, &transparent_hugepage_flags); 26471e3aac0SAndrea Arcangeli } else if (!memcmp("never", buf, 26571e3aac0SAndrea Arcangeli min(sizeof("never")-1, count))) { 26671e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 26771e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 26871e3aac0SAndrea Arcangeli } else 26971e3aac0SAndrea Arcangeli return -EINVAL; 27071e3aac0SAndrea Arcangeli 27171e3aac0SAndrea Arcangeli return count; 27271e3aac0SAndrea Arcangeli } 27371e3aac0SAndrea Arcangeli 27471e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 27571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 27671e3aac0SAndrea Arcangeli { 27771e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 27871e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 27971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 28071e3aac0SAndrea Arcangeli } 28171e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 28271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 28371e3aac0SAndrea Arcangeli const char *buf, size_t count) 28471e3aac0SAndrea Arcangeli { 285ba76149fSAndrea Arcangeli ssize_t ret; 286ba76149fSAndrea Arcangeli 287ba76149fSAndrea Arcangeli ret = double_flag_store(kobj, attr, buf, count, 28871e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 28971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 290ba76149fSAndrea Arcangeli 291ba76149fSAndrea Arcangeli if (ret > 0) { 292911891afSXiao Guangrong int err; 293911891afSXiao Guangrong 294911891afSXiao Guangrong mutex_lock(&khugepaged_mutex); 295911891afSXiao Guangrong err = start_khugepaged(); 296911891afSXiao Guangrong mutex_unlock(&khugepaged_mutex); 297911891afSXiao Guangrong 298ba76149fSAndrea Arcangeli if (err) 299ba76149fSAndrea Arcangeli ret = err; 300ba76149fSAndrea Arcangeli } 301ba76149fSAndrea Arcangeli 302ba76149fSAndrea Arcangeli return ret; 30371e3aac0SAndrea Arcangeli } 30471e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 30571e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 30671e3aac0SAndrea Arcangeli 30771e3aac0SAndrea Arcangeli static ssize_t single_flag_show(struct kobject *kobj, 30871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 30971e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 31071e3aac0SAndrea Arcangeli { 311e27e6151SBen Hutchings return sprintf(buf, "%d\n", 312e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 31371e3aac0SAndrea Arcangeli } 314e27e6151SBen Hutchings 31571e3aac0SAndrea Arcangeli static ssize_t single_flag_store(struct kobject *kobj, 31671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 31771e3aac0SAndrea Arcangeli const char *buf, size_t count, 31871e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 31971e3aac0SAndrea Arcangeli { 320e27e6151SBen Hutchings unsigned long value; 321e27e6151SBen Hutchings int ret; 322e27e6151SBen Hutchings 323e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 324e27e6151SBen Hutchings if (ret < 0) 325e27e6151SBen Hutchings return ret; 326e27e6151SBen Hutchings if (value > 1) 32771e3aac0SAndrea Arcangeli return -EINVAL; 32871e3aac0SAndrea Arcangeli 329e27e6151SBen Hutchings if (value) 330e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 331e27e6151SBen Hutchings else 332e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 333e27e6151SBen Hutchings 33471e3aac0SAndrea Arcangeli return count; 33571e3aac0SAndrea Arcangeli } 33671e3aac0SAndrea Arcangeli 33771e3aac0SAndrea Arcangeli /* 33871e3aac0SAndrea Arcangeli * Currently defrag only disables __GFP_NOWAIT for allocation. A blind 33971e3aac0SAndrea Arcangeli * __GFP_REPEAT is too aggressive, it's never worth swapping tons of 34071e3aac0SAndrea Arcangeli * memory just to allocate one more hugepage. 34171e3aac0SAndrea Arcangeli */ 34271e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 34371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 34471e3aac0SAndrea Arcangeli { 34571e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 34671e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 34771e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 34871e3aac0SAndrea Arcangeli } 34971e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 35071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 35171e3aac0SAndrea Arcangeli const char *buf, size_t count) 35271e3aac0SAndrea Arcangeli { 35371e3aac0SAndrea Arcangeli return double_flag_store(kobj, attr, buf, count, 35471e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 35571e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 35671e3aac0SAndrea Arcangeli } 35771e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 35871e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 35971e3aac0SAndrea Arcangeli 36079da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 36179da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 36279da5407SKirill A. Shutemov { 36379da5407SKirill A. Shutemov return single_flag_show(kobj, attr, buf, 36479da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 36579da5407SKirill A. Shutemov } 36679da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 36779da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 36879da5407SKirill A. Shutemov { 36979da5407SKirill A. Shutemov return single_flag_store(kobj, attr, buf, count, 37079da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 37179da5407SKirill A. Shutemov } 37279da5407SKirill A. Shutemov static struct kobj_attribute use_zero_page_attr = 37379da5407SKirill A. Shutemov __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); 37471e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 37571e3aac0SAndrea Arcangeli static ssize_t debug_cow_show(struct kobject *kobj, 37671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 37771e3aac0SAndrea Arcangeli { 37871e3aac0SAndrea Arcangeli return single_flag_show(kobj, attr, buf, 37971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 38071e3aac0SAndrea Arcangeli } 38171e3aac0SAndrea Arcangeli static ssize_t debug_cow_store(struct kobject *kobj, 38271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 38371e3aac0SAndrea Arcangeli const char *buf, size_t count) 38471e3aac0SAndrea Arcangeli { 38571e3aac0SAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 38671e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 38771e3aac0SAndrea Arcangeli } 38871e3aac0SAndrea Arcangeli static struct kobj_attribute debug_cow_attr = 38971e3aac0SAndrea Arcangeli __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); 39071e3aac0SAndrea Arcangeli #endif /* CONFIG_DEBUG_VM */ 39171e3aac0SAndrea Arcangeli 39271e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 39371e3aac0SAndrea Arcangeli &enabled_attr.attr, 39471e3aac0SAndrea Arcangeli &defrag_attr.attr, 39579da5407SKirill A. Shutemov &use_zero_page_attr.attr, 39671e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 39771e3aac0SAndrea Arcangeli &debug_cow_attr.attr, 39871e3aac0SAndrea Arcangeli #endif 39971e3aac0SAndrea Arcangeli NULL, 40071e3aac0SAndrea Arcangeli }; 40171e3aac0SAndrea Arcangeli 40271e3aac0SAndrea Arcangeli static struct attribute_group hugepage_attr_group = { 40371e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 404ba76149fSAndrea Arcangeli }; 405ba76149fSAndrea Arcangeli 406ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, 407ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 408ba76149fSAndrea Arcangeli char *buf) 409ba76149fSAndrea Arcangeli { 410ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); 411ba76149fSAndrea Arcangeli } 412ba76149fSAndrea Arcangeli 413ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, 414ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 415ba76149fSAndrea Arcangeli const char *buf, size_t count) 416ba76149fSAndrea Arcangeli { 417ba76149fSAndrea Arcangeli unsigned long msecs; 418ba76149fSAndrea Arcangeli int err; 419ba76149fSAndrea Arcangeli 4203dbb95f7SJingoo Han err = kstrtoul(buf, 10, &msecs); 421ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 422ba76149fSAndrea Arcangeli return -EINVAL; 423ba76149fSAndrea Arcangeli 424ba76149fSAndrea Arcangeli khugepaged_scan_sleep_millisecs = msecs; 425ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 426ba76149fSAndrea Arcangeli 427ba76149fSAndrea Arcangeli return count; 428ba76149fSAndrea Arcangeli } 429ba76149fSAndrea Arcangeli static struct kobj_attribute scan_sleep_millisecs_attr = 430ba76149fSAndrea Arcangeli __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, 431ba76149fSAndrea Arcangeli scan_sleep_millisecs_store); 432ba76149fSAndrea Arcangeli 433ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, 434ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 435ba76149fSAndrea Arcangeli char *buf) 436ba76149fSAndrea Arcangeli { 437ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); 438ba76149fSAndrea Arcangeli } 439ba76149fSAndrea Arcangeli 440ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, 441ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 442ba76149fSAndrea Arcangeli const char *buf, size_t count) 443ba76149fSAndrea Arcangeli { 444ba76149fSAndrea Arcangeli unsigned long msecs; 445ba76149fSAndrea Arcangeli int err; 446ba76149fSAndrea Arcangeli 4473dbb95f7SJingoo Han err = kstrtoul(buf, 10, &msecs); 448ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 449ba76149fSAndrea Arcangeli return -EINVAL; 450ba76149fSAndrea Arcangeli 451ba76149fSAndrea Arcangeli khugepaged_alloc_sleep_millisecs = msecs; 452ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 453ba76149fSAndrea Arcangeli 454ba76149fSAndrea Arcangeli return count; 455ba76149fSAndrea Arcangeli } 456ba76149fSAndrea Arcangeli static struct kobj_attribute alloc_sleep_millisecs_attr = 457ba76149fSAndrea Arcangeli __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, 458ba76149fSAndrea Arcangeli alloc_sleep_millisecs_store); 459ba76149fSAndrea Arcangeli 460ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_show(struct kobject *kobj, 461ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 462ba76149fSAndrea Arcangeli char *buf) 463ba76149fSAndrea Arcangeli { 464ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_to_scan); 465ba76149fSAndrea Arcangeli } 466ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_store(struct kobject *kobj, 467ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 468ba76149fSAndrea Arcangeli const char *buf, size_t count) 469ba76149fSAndrea Arcangeli { 470ba76149fSAndrea Arcangeli int err; 471ba76149fSAndrea Arcangeli unsigned long pages; 472ba76149fSAndrea Arcangeli 4733dbb95f7SJingoo Han err = kstrtoul(buf, 10, &pages); 474ba76149fSAndrea Arcangeli if (err || !pages || pages > UINT_MAX) 475ba76149fSAndrea Arcangeli return -EINVAL; 476ba76149fSAndrea Arcangeli 477ba76149fSAndrea Arcangeli khugepaged_pages_to_scan = pages; 478ba76149fSAndrea Arcangeli 479ba76149fSAndrea Arcangeli return count; 480ba76149fSAndrea Arcangeli } 481ba76149fSAndrea Arcangeli static struct kobj_attribute pages_to_scan_attr = 482ba76149fSAndrea Arcangeli __ATTR(pages_to_scan, 0644, pages_to_scan_show, 483ba76149fSAndrea Arcangeli pages_to_scan_store); 484ba76149fSAndrea Arcangeli 485ba76149fSAndrea Arcangeli static ssize_t pages_collapsed_show(struct kobject *kobj, 486ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 487ba76149fSAndrea Arcangeli char *buf) 488ba76149fSAndrea Arcangeli { 489ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_collapsed); 490ba76149fSAndrea Arcangeli } 491ba76149fSAndrea Arcangeli static struct kobj_attribute pages_collapsed_attr = 492ba76149fSAndrea Arcangeli __ATTR_RO(pages_collapsed); 493ba76149fSAndrea Arcangeli 494ba76149fSAndrea Arcangeli static ssize_t full_scans_show(struct kobject *kobj, 495ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 496ba76149fSAndrea Arcangeli char *buf) 497ba76149fSAndrea Arcangeli { 498ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_full_scans); 499ba76149fSAndrea Arcangeli } 500ba76149fSAndrea Arcangeli static struct kobj_attribute full_scans_attr = 501ba76149fSAndrea Arcangeli __ATTR_RO(full_scans); 502ba76149fSAndrea Arcangeli 503ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_show(struct kobject *kobj, 504ba76149fSAndrea Arcangeli struct kobj_attribute *attr, char *buf) 505ba76149fSAndrea Arcangeli { 506ba76149fSAndrea Arcangeli return single_flag_show(kobj, attr, buf, 507ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 508ba76149fSAndrea Arcangeli } 509ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_store(struct kobject *kobj, 510ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 511ba76149fSAndrea Arcangeli const char *buf, size_t count) 512ba76149fSAndrea Arcangeli { 513ba76149fSAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 514ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 515ba76149fSAndrea Arcangeli } 516ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_defrag_attr = 517ba76149fSAndrea Arcangeli __ATTR(defrag, 0644, khugepaged_defrag_show, 518ba76149fSAndrea Arcangeli khugepaged_defrag_store); 519ba76149fSAndrea Arcangeli 520ba76149fSAndrea Arcangeli /* 521ba76149fSAndrea Arcangeli * max_ptes_none controls if khugepaged should collapse hugepages over 522ba76149fSAndrea Arcangeli * any unmapped ptes in turn potentially increasing the memory 523ba76149fSAndrea Arcangeli * footprint of the vmas. When max_ptes_none is 0 khugepaged will not 524ba76149fSAndrea Arcangeli * reduce the available free memory in the system as it 525ba76149fSAndrea Arcangeli * runs. Increasing max_ptes_none will instead potentially reduce the 526ba76149fSAndrea Arcangeli * free memory in the system during the khugepaged scan. 527ba76149fSAndrea Arcangeli */ 528ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, 529ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 530ba76149fSAndrea Arcangeli char *buf) 531ba76149fSAndrea Arcangeli { 532ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_max_ptes_none); 533ba76149fSAndrea Arcangeli } 534ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, 535ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 536ba76149fSAndrea Arcangeli const char *buf, size_t count) 537ba76149fSAndrea Arcangeli { 538ba76149fSAndrea Arcangeli int err; 539ba76149fSAndrea Arcangeli unsigned long max_ptes_none; 540ba76149fSAndrea Arcangeli 5413dbb95f7SJingoo Han err = kstrtoul(buf, 10, &max_ptes_none); 542ba76149fSAndrea Arcangeli if (err || max_ptes_none > HPAGE_PMD_NR-1) 543ba76149fSAndrea Arcangeli return -EINVAL; 544ba76149fSAndrea Arcangeli 545ba76149fSAndrea Arcangeli khugepaged_max_ptes_none = max_ptes_none; 546ba76149fSAndrea Arcangeli 547ba76149fSAndrea Arcangeli return count; 548ba76149fSAndrea Arcangeli } 549ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_max_ptes_none_attr = 550ba76149fSAndrea Arcangeli __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, 551ba76149fSAndrea Arcangeli khugepaged_max_ptes_none_store); 552ba76149fSAndrea Arcangeli 553ba76149fSAndrea Arcangeli static struct attribute *khugepaged_attr[] = { 554ba76149fSAndrea Arcangeli &khugepaged_defrag_attr.attr, 555ba76149fSAndrea Arcangeli &khugepaged_max_ptes_none_attr.attr, 556ba76149fSAndrea Arcangeli &pages_to_scan_attr.attr, 557ba76149fSAndrea Arcangeli &pages_collapsed_attr.attr, 558ba76149fSAndrea Arcangeli &full_scans_attr.attr, 559ba76149fSAndrea Arcangeli &scan_sleep_millisecs_attr.attr, 560ba76149fSAndrea Arcangeli &alloc_sleep_millisecs_attr.attr, 561ba76149fSAndrea Arcangeli NULL, 562ba76149fSAndrea Arcangeli }; 563ba76149fSAndrea Arcangeli 564ba76149fSAndrea Arcangeli static struct attribute_group khugepaged_attr_group = { 565ba76149fSAndrea Arcangeli .attrs = khugepaged_attr, 566ba76149fSAndrea Arcangeli .name = "khugepaged", 56771e3aac0SAndrea Arcangeli }; 568569e5590SShaohua Li 569569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 570569e5590SShaohua Li { 571569e5590SShaohua Li int err; 572569e5590SShaohua Li 573569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 574569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 5752c79737aSJeremy Eder printk(KERN_ERR "hugepage: failed to create transparent hugepage kobject\n"); 576569e5590SShaohua Li return -ENOMEM; 577569e5590SShaohua Li } 578569e5590SShaohua Li 579569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 580569e5590SShaohua Li if (err) { 5812c79737aSJeremy Eder printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); 582569e5590SShaohua Li goto delete_obj; 583569e5590SShaohua Li } 584569e5590SShaohua Li 585569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 586569e5590SShaohua Li if (err) { 5872c79737aSJeremy Eder printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); 588569e5590SShaohua Li goto remove_hp_group; 589569e5590SShaohua Li } 590569e5590SShaohua Li 591569e5590SShaohua Li return 0; 592569e5590SShaohua Li 593569e5590SShaohua Li remove_hp_group: 594569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 595569e5590SShaohua Li delete_obj: 596569e5590SShaohua Li kobject_put(*hugepage_kobj); 597569e5590SShaohua Li return err; 598569e5590SShaohua Li } 599569e5590SShaohua Li 600569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 601569e5590SShaohua Li { 602569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 603569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 604569e5590SShaohua Li kobject_put(hugepage_kobj); 605569e5590SShaohua Li } 606569e5590SShaohua Li #else 607569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 608569e5590SShaohua Li { 609569e5590SShaohua Li return 0; 610569e5590SShaohua Li } 611569e5590SShaohua Li 612569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 613569e5590SShaohua Li { 614569e5590SShaohua Li } 61571e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 61671e3aac0SAndrea Arcangeli 61771e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 61871e3aac0SAndrea Arcangeli { 61971e3aac0SAndrea Arcangeli int err; 620569e5590SShaohua Li struct kobject *hugepage_kobj; 62171e3aac0SAndrea Arcangeli 6224b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 6234b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 624569e5590SShaohua Li return -EINVAL; 6254b7167b9SAndrea Arcangeli } 6264b7167b9SAndrea Arcangeli 627569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 628569e5590SShaohua Li if (err) 629569e5590SShaohua Li return err; 630ba76149fSAndrea Arcangeli 631ba76149fSAndrea Arcangeli err = khugepaged_slab_init(); 632ba76149fSAndrea Arcangeli if (err) 633ba76149fSAndrea Arcangeli goto out; 634ba76149fSAndrea Arcangeli 63597ae1749SKirill A. Shutemov register_shrinker(&huge_zero_page_shrinker); 63697ae1749SKirill A. Shutemov 63797562cd2SRik van Riel /* 63897562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 63997562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 64097562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 64197562cd2SRik van Riel */ 64297562cd2SRik van Riel if (totalram_pages < (512 << (20 - PAGE_SHIFT))) 64397562cd2SRik van Riel transparent_hugepage_flags = 0; 64497562cd2SRik van Riel 645ba76149fSAndrea Arcangeli start_khugepaged(); 646ba76149fSAndrea Arcangeli 647569e5590SShaohua Li return 0; 648ba76149fSAndrea Arcangeli out: 649569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 650ba76149fSAndrea Arcangeli return err; 65171e3aac0SAndrea Arcangeli } 65271e3aac0SAndrea Arcangeli module_init(hugepage_init) 65371e3aac0SAndrea Arcangeli 65471e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 65571e3aac0SAndrea Arcangeli { 65671e3aac0SAndrea Arcangeli int ret = 0; 65771e3aac0SAndrea Arcangeli if (!str) 65871e3aac0SAndrea Arcangeli goto out; 65971e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 66071e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 66171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 66271e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 66371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 66471e3aac0SAndrea Arcangeli ret = 1; 66571e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 66671e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 66771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 66871e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 66971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 67071e3aac0SAndrea Arcangeli ret = 1; 67171e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 67271e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 67371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 67471e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 67571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 67671e3aac0SAndrea Arcangeli ret = 1; 67771e3aac0SAndrea Arcangeli } 67871e3aac0SAndrea Arcangeli out: 67971e3aac0SAndrea Arcangeli if (!ret) 68071e3aac0SAndrea Arcangeli printk(KERN_WARNING 68171e3aac0SAndrea Arcangeli "transparent_hugepage= cannot parse, ignored\n"); 68271e3aac0SAndrea Arcangeli return ret; 68371e3aac0SAndrea Arcangeli } 68471e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 68571e3aac0SAndrea Arcangeli 686b32967ffSMel Gorman pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 68771e3aac0SAndrea Arcangeli { 68871e3aac0SAndrea Arcangeli if (likely(vma->vm_flags & VM_WRITE)) 68971e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 69071e3aac0SAndrea Arcangeli return pmd; 69171e3aac0SAndrea Arcangeli } 69271e3aac0SAndrea Arcangeli 693*3122359aSKirill A. Shutemov static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot) 694b3092b3bSBob Liu { 695b3092b3bSBob Liu pmd_t entry; 696*3122359aSKirill A. Shutemov entry = mk_pmd(page, prot); 697b3092b3bSBob Liu entry = pmd_mkhuge(entry); 698b3092b3bSBob Liu return entry; 699b3092b3bSBob Liu } 700b3092b3bSBob Liu 70171e3aac0SAndrea Arcangeli static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, 70271e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 70371e3aac0SAndrea Arcangeli unsigned long haddr, pmd_t *pmd, 70471e3aac0SAndrea Arcangeli struct page *page) 70571e3aac0SAndrea Arcangeli { 70671e3aac0SAndrea Arcangeli pgtable_t pgtable; 70771e3aac0SAndrea Arcangeli 70871e3aac0SAndrea Arcangeli VM_BUG_ON(!PageCompound(page)); 70971e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(mm, haddr); 710edad9d2cSDavid Rientjes if (unlikely(!pgtable)) 71171e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 71271e3aac0SAndrea Arcangeli 71371e3aac0SAndrea Arcangeli clear_huge_page(page, haddr, HPAGE_PMD_NR); 71452f37629SMinchan Kim /* 71552f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 71652f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 71752f37629SMinchan Kim * write. 71852f37629SMinchan Kim */ 71971e3aac0SAndrea Arcangeli __SetPageUptodate(page); 72071e3aac0SAndrea Arcangeli 72171e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 72271e3aac0SAndrea Arcangeli if (unlikely(!pmd_none(*pmd))) { 72371e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 724b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(page); 72571e3aac0SAndrea Arcangeli put_page(page); 72671e3aac0SAndrea Arcangeli pte_free(mm, pgtable); 72771e3aac0SAndrea Arcangeli } else { 72871e3aac0SAndrea Arcangeli pmd_t entry; 729*3122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 730*3122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 73171e3aac0SAndrea Arcangeli page_add_new_anon_rmap(page, vma, haddr); 7326b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 73371e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 73471e3aac0SAndrea Arcangeli add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 7351c641e84SAndrea Arcangeli mm->nr_ptes++; 73671e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 73771e3aac0SAndrea Arcangeli } 73871e3aac0SAndrea Arcangeli 739aa2e878eSDavid Rientjes return 0; 74071e3aac0SAndrea Arcangeli } 74171e3aac0SAndrea Arcangeli 742cc5d462fSAndi Kleen static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) 7430bbbc0b3SAndrea Arcangeli { 744cc5d462fSAndi Kleen return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; 7450bbbc0b3SAndrea Arcangeli } 7460bbbc0b3SAndrea Arcangeli 7470bbbc0b3SAndrea Arcangeli static inline struct page *alloc_hugepage_vma(int defrag, 7480bbbc0b3SAndrea Arcangeli struct vm_area_struct *vma, 749cc5d462fSAndi Kleen unsigned long haddr, int nd, 750cc5d462fSAndi Kleen gfp_t extra_gfp) 7510bbbc0b3SAndrea Arcangeli { 752cc5d462fSAndi Kleen return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), 7535c4b4be3SAndi Kleen HPAGE_PMD_ORDER, vma, haddr, nd); 7540bbbc0b3SAndrea Arcangeli } 7550bbbc0b3SAndrea Arcangeli 7560bbbc0b3SAndrea Arcangeli #ifndef CONFIG_NUMA 75771e3aac0SAndrea Arcangeli static inline struct page *alloc_hugepage(int defrag) 75871e3aac0SAndrea Arcangeli { 759cc5d462fSAndi Kleen return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), 76071e3aac0SAndrea Arcangeli HPAGE_PMD_ORDER); 76171e3aac0SAndrea Arcangeli } 7620bbbc0b3SAndrea Arcangeli #endif 76371e3aac0SAndrea Arcangeli 7643ea41e62SKirill A. Shutemov static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 76597ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 7665918d10aSKirill A. Shutemov struct page *zero_page) 767fc9fe822SKirill A. Shutemov { 768fc9fe822SKirill A. Shutemov pmd_t entry; 7693ea41e62SKirill A. Shutemov if (!pmd_none(*pmd)) 7703ea41e62SKirill A. Shutemov return false; 7715918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 772fc9fe822SKirill A. Shutemov entry = pmd_wrprotect(entry); 773fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 7746b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 775fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 776fc9fe822SKirill A. Shutemov mm->nr_ptes++; 7773ea41e62SKirill A. Shutemov return true; 778fc9fe822SKirill A. Shutemov } 779fc9fe822SKirill A. Shutemov 78071e3aac0SAndrea Arcangeli int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 78171e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, 78271e3aac0SAndrea Arcangeli unsigned int flags) 78371e3aac0SAndrea Arcangeli { 78471e3aac0SAndrea Arcangeli struct page *page; 78571e3aac0SAndrea Arcangeli unsigned long haddr = address & HPAGE_PMD_MASK; 78671e3aac0SAndrea Arcangeli pte_t *pte; 78771e3aac0SAndrea Arcangeli 78871e3aac0SAndrea Arcangeli if (haddr >= vma->vm_start && haddr + HPAGE_PMD_SIZE <= vma->vm_end) { 78971e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 79071e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 791ba76149fSAndrea Arcangeli if (unlikely(khugepaged_enter(vma))) 792ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 79379da5407SKirill A. Shutemov if (!(flags & FAULT_FLAG_WRITE) && 79479da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 79580371957SKirill A. Shutemov pgtable_t pgtable; 7965918d10aSKirill A. Shutemov struct page *zero_page; 7973ea41e62SKirill A. Shutemov bool set; 79880371957SKirill A. Shutemov pgtable = pte_alloc_one(mm, haddr); 79980371957SKirill A. Shutemov if (unlikely(!pgtable)) 80080371957SKirill A. Shutemov return VM_FAULT_OOM; 8015918d10aSKirill A. Shutemov zero_page = get_huge_zero_page(); 8025918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 80397ae1749SKirill A. Shutemov pte_free(mm, pgtable); 80497ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 80597ae1749SKirill A. Shutemov goto out; 80697ae1749SKirill A. Shutemov } 80780371957SKirill A. Shutemov spin_lock(&mm->page_table_lock); 8083ea41e62SKirill A. Shutemov set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd, 8095918d10aSKirill A. Shutemov zero_page); 81080371957SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 8113ea41e62SKirill A. Shutemov if (!set) { 8123ea41e62SKirill A. Shutemov pte_free(mm, pgtable); 8133ea41e62SKirill A. Shutemov put_huge_zero_page(); 8143ea41e62SKirill A. Shutemov } 81580371957SKirill A. Shutemov return 0; 81680371957SKirill A. Shutemov } 8170bbbc0b3SAndrea Arcangeli page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), 818cc5d462fSAndi Kleen vma, haddr, numa_node_id(), 0); 81981ab4201SAndi Kleen if (unlikely(!page)) { 82081ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 82171e3aac0SAndrea Arcangeli goto out; 82281ab4201SAndi Kleen } 82381ab4201SAndi Kleen count_vm_event(THP_FAULT_ALLOC); 824b9bbfbe3SAndrea Arcangeli if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { 825b9bbfbe3SAndrea Arcangeli put_page(page); 826b9bbfbe3SAndrea Arcangeli goto out; 827b9bbfbe3SAndrea Arcangeli } 828edad9d2cSDavid Rientjes if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, 829edad9d2cSDavid Rientjes page))) { 830edad9d2cSDavid Rientjes mem_cgroup_uncharge_page(page); 831edad9d2cSDavid Rientjes put_page(page); 832edad9d2cSDavid Rientjes goto out; 833edad9d2cSDavid Rientjes } 83471e3aac0SAndrea Arcangeli 835edad9d2cSDavid Rientjes return 0; 83671e3aac0SAndrea Arcangeli } 83771e3aac0SAndrea Arcangeli out: 83871e3aac0SAndrea Arcangeli /* 83971e3aac0SAndrea Arcangeli * Use __pte_alloc instead of pte_alloc_map, because we can't 84071e3aac0SAndrea Arcangeli * run pte_offset_map on the pmd, if an huge pmd could 84171e3aac0SAndrea Arcangeli * materialize from under us from a different thread. 84271e3aac0SAndrea Arcangeli */ 8434fd01770SMel Gorman if (unlikely(pmd_none(*pmd)) && 8444fd01770SMel Gorman unlikely(__pte_alloc(mm, vma, pmd, address))) 84571e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 84671e3aac0SAndrea Arcangeli /* if an huge pmd materialized from under us just retry later */ 84771e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_huge(*pmd))) 84871e3aac0SAndrea Arcangeli return 0; 84971e3aac0SAndrea Arcangeli /* 85071e3aac0SAndrea Arcangeli * A regular pmd is established and it can't morph into a huge pmd 85171e3aac0SAndrea Arcangeli * from under us anymore at this point because we hold the mmap_sem 85271e3aac0SAndrea Arcangeli * read mode and khugepaged takes it in write mode. So now it's 85371e3aac0SAndrea Arcangeli * safe to run pte_offset_map(). 85471e3aac0SAndrea Arcangeli */ 85571e3aac0SAndrea Arcangeli pte = pte_offset_map(pmd, address); 85671e3aac0SAndrea Arcangeli return handle_pte_fault(mm, vma, address, pte, pmd, flags); 85771e3aac0SAndrea Arcangeli } 85871e3aac0SAndrea Arcangeli 85971e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 86071e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 86171e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 86271e3aac0SAndrea Arcangeli { 86371e3aac0SAndrea Arcangeli struct page *src_page; 86471e3aac0SAndrea Arcangeli pmd_t pmd; 86571e3aac0SAndrea Arcangeli pgtable_t pgtable; 86671e3aac0SAndrea Arcangeli int ret; 86771e3aac0SAndrea Arcangeli 86871e3aac0SAndrea Arcangeli ret = -ENOMEM; 86971e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(dst_mm, addr); 87071e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 87171e3aac0SAndrea Arcangeli goto out; 87271e3aac0SAndrea Arcangeli 87371e3aac0SAndrea Arcangeli spin_lock(&dst_mm->page_table_lock); 87471e3aac0SAndrea Arcangeli spin_lock_nested(&src_mm->page_table_lock, SINGLE_DEPTH_NESTING); 87571e3aac0SAndrea Arcangeli 87671e3aac0SAndrea Arcangeli ret = -EAGAIN; 87771e3aac0SAndrea Arcangeli pmd = *src_pmd; 87871e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(pmd))) { 87971e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 88071e3aac0SAndrea Arcangeli goto out_unlock; 88171e3aac0SAndrea Arcangeli } 882fc9fe822SKirill A. Shutemov /* 883fc9fe822SKirill A. Shutemov * mm->page_table_lock is enough to be sure that huge zero pmd is not 884fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 885fc9fe822SKirill A. Shutemov * a page table. 886fc9fe822SKirill A. Shutemov */ 887fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 8885918d10aSKirill A. Shutemov struct page *zero_page; 8893ea41e62SKirill A. Shutemov bool set; 89097ae1749SKirill A. Shutemov /* 89197ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 89297ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 89397ae1749SKirill A. Shutemov * reference. 89497ae1749SKirill A. Shutemov */ 8955918d10aSKirill A. Shutemov zero_page = get_huge_zero_page(); 8963ea41e62SKirill A. Shutemov set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, 8975918d10aSKirill A. Shutemov zero_page); 8983ea41e62SKirill A. Shutemov BUG_ON(!set); /* unexpected !pmd_none(dst_pmd) */ 899fc9fe822SKirill A. Shutemov ret = 0; 900fc9fe822SKirill A. Shutemov goto out_unlock; 901fc9fe822SKirill A. Shutemov } 90271e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_splitting(pmd))) { 90371e3aac0SAndrea Arcangeli /* split huge page running from under us */ 90471e3aac0SAndrea Arcangeli spin_unlock(&src_mm->page_table_lock); 90571e3aac0SAndrea Arcangeli spin_unlock(&dst_mm->page_table_lock); 90671e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 90771e3aac0SAndrea Arcangeli 90871e3aac0SAndrea Arcangeli wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ 90971e3aac0SAndrea Arcangeli goto out; 91071e3aac0SAndrea Arcangeli } 91171e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 91271e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(src_page)); 91371e3aac0SAndrea Arcangeli get_page(src_page); 91471e3aac0SAndrea Arcangeli page_dup_rmap(src_page); 91571e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 91671e3aac0SAndrea Arcangeli 91771e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 91871e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 9196b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 92071e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 9211c641e84SAndrea Arcangeli dst_mm->nr_ptes++; 92271e3aac0SAndrea Arcangeli 92371e3aac0SAndrea Arcangeli ret = 0; 92471e3aac0SAndrea Arcangeli out_unlock: 92571e3aac0SAndrea Arcangeli spin_unlock(&src_mm->page_table_lock); 92671e3aac0SAndrea Arcangeli spin_unlock(&dst_mm->page_table_lock); 92771e3aac0SAndrea Arcangeli out: 92871e3aac0SAndrea Arcangeli return ret; 92971e3aac0SAndrea Arcangeli } 93071e3aac0SAndrea Arcangeli 931a1dd450bSWill Deacon void huge_pmd_set_accessed(struct mm_struct *mm, 932a1dd450bSWill Deacon struct vm_area_struct *vma, 933a1dd450bSWill Deacon unsigned long address, 934a1dd450bSWill Deacon pmd_t *pmd, pmd_t orig_pmd, 935a1dd450bSWill Deacon int dirty) 936a1dd450bSWill Deacon { 937a1dd450bSWill Deacon pmd_t entry; 938a1dd450bSWill Deacon unsigned long haddr; 939a1dd450bSWill Deacon 940a1dd450bSWill Deacon spin_lock(&mm->page_table_lock); 941a1dd450bSWill Deacon if (unlikely(!pmd_same(*pmd, orig_pmd))) 942a1dd450bSWill Deacon goto unlock; 943a1dd450bSWill Deacon 944a1dd450bSWill Deacon entry = pmd_mkyoung(orig_pmd); 945a1dd450bSWill Deacon haddr = address & HPAGE_PMD_MASK; 946a1dd450bSWill Deacon if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) 947a1dd450bSWill Deacon update_mmu_cache_pmd(vma, address, pmd); 948a1dd450bSWill Deacon 949a1dd450bSWill Deacon unlock: 950a1dd450bSWill Deacon spin_unlock(&mm->page_table_lock); 951a1dd450bSWill Deacon } 952a1dd450bSWill Deacon 95393b4796dSKirill A. Shutemov static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm, 95493b4796dSKirill A. Shutemov struct vm_area_struct *vma, unsigned long address, 9553ea41e62SKirill A. Shutemov pmd_t *pmd, pmd_t orig_pmd, unsigned long haddr) 95693b4796dSKirill A. Shutemov { 95793b4796dSKirill A. Shutemov pgtable_t pgtable; 95893b4796dSKirill A. Shutemov pmd_t _pmd; 95993b4796dSKirill A. Shutemov struct page *page; 96093b4796dSKirill A. Shutemov int i, ret = 0; 96193b4796dSKirill A. Shutemov unsigned long mmun_start; /* For mmu_notifiers */ 96293b4796dSKirill A. Shutemov unsigned long mmun_end; /* For mmu_notifiers */ 96393b4796dSKirill A. Shutemov 96493b4796dSKirill A. Shutemov page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); 96593b4796dSKirill A. Shutemov if (!page) { 96693b4796dSKirill A. Shutemov ret |= VM_FAULT_OOM; 96793b4796dSKirill A. Shutemov goto out; 96893b4796dSKirill A. Shutemov } 96993b4796dSKirill A. Shutemov 97093b4796dSKirill A. Shutemov if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) { 97193b4796dSKirill A. Shutemov put_page(page); 97293b4796dSKirill A. Shutemov ret |= VM_FAULT_OOM; 97393b4796dSKirill A. Shutemov goto out; 97493b4796dSKirill A. Shutemov } 97593b4796dSKirill A. Shutemov 97693b4796dSKirill A. Shutemov clear_user_highpage(page, address); 97793b4796dSKirill A. Shutemov __SetPageUptodate(page); 97893b4796dSKirill A. Shutemov 97993b4796dSKirill A. Shutemov mmun_start = haddr; 98093b4796dSKirill A. Shutemov mmun_end = haddr + HPAGE_PMD_SIZE; 98193b4796dSKirill A. Shutemov mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 98293b4796dSKirill A. Shutemov 98393b4796dSKirill A. Shutemov spin_lock(&mm->page_table_lock); 9843ea41e62SKirill A. Shutemov if (unlikely(!pmd_same(*pmd, orig_pmd))) 9853ea41e62SKirill A. Shutemov goto out_free_page; 9863ea41e62SKirill A. Shutemov 98793b4796dSKirill A. Shutemov pmdp_clear_flush(vma, haddr, pmd); 98893b4796dSKirill A. Shutemov /* leave pmd empty until pte is filled */ 98993b4796dSKirill A. Shutemov 9906b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 99193b4796dSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 99293b4796dSKirill A. Shutemov 99393b4796dSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 99493b4796dSKirill A. Shutemov pte_t *pte, entry; 99593b4796dSKirill A. Shutemov if (haddr == (address & PAGE_MASK)) { 99693b4796dSKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 99793b4796dSKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 99893b4796dSKirill A. Shutemov page_add_new_anon_rmap(page, vma, haddr); 99993b4796dSKirill A. Shutemov } else { 100093b4796dSKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 100193b4796dSKirill A. Shutemov entry = pte_mkspecial(entry); 100293b4796dSKirill A. Shutemov } 100393b4796dSKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 100493b4796dSKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 100593b4796dSKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 100693b4796dSKirill A. Shutemov pte_unmap(pte); 100793b4796dSKirill A. Shutemov } 100893b4796dSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 100993b4796dSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 101093b4796dSKirill A. Shutemov spin_unlock(&mm->page_table_lock); 101197ae1749SKirill A. Shutemov put_huge_zero_page(); 101293b4796dSKirill A. Shutemov inc_mm_counter(mm, MM_ANONPAGES); 101393b4796dSKirill A. Shutemov 101493b4796dSKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 101593b4796dSKirill A. Shutemov 101693b4796dSKirill A. Shutemov ret |= VM_FAULT_WRITE; 101793b4796dSKirill A. Shutemov out: 101893b4796dSKirill A. Shutemov return ret; 10193ea41e62SKirill A. Shutemov out_free_page: 10203ea41e62SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 10213ea41e62SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 10223ea41e62SKirill A. Shutemov mem_cgroup_uncharge_page(page); 10233ea41e62SKirill A. Shutemov put_page(page); 10243ea41e62SKirill A. Shutemov goto out; 102593b4796dSKirill A. Shutemov } 102693b4796dSKirill A. Shutemov 102771e3aac0SAndrea Arcangeli static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, 102871e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 102971e3aac0SAndrea Arcangeli unsigned long address, 103071e3aac0SAndrea Arcangeli pmd_t *pmd, pmd_t orig_pmd, 103171e3aac0SAndrea Arcangeli struct page *page, 103271e3aac0SAndrea Arcangeli unsigned long haddr) 103371e3aac0SAndrea Arcangeli { 103471e3aac0SAndrea Arcangeli pgtable_t pgtable; 103571e3aac0SAndrea Arcangeli pmd_t _pmd; 103671e3aac0SAndrea Arcangeli int ret = 0, i; 103771e3aac0SAndrea Arcangeli struct page **pages; 10382ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 10392ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 104071e3aac0SAndrea Arcangeli 104171e3aac0SAndrea Arcangeli pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, 104271e3aac0SAndrea Arcangeli GFP_KERNEL); 104371e3aac0SAndrea Arcangeli if (unlikely(!pages)) { 104471e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 104571e3aac0SAndrea Arcangeli goto out; 104671e3aac0SAndrea Arcangeli } 104771e3aac0SAndrea Arcangeli 104871e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 1049cc5d462fSAndi Kleen pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | 1050cc5d462fSAndi Kleen __GFP_OTHER_NODE, 105119ee151eSAndi Kleen vma, address, page_to_nid(page)); 1052b9bbfbe3SAndrea Arcangeli if (unlikely(!pages[i] || 1053b9bbfbe3SAndrea Arcangeli mem_cgroup_newpage_charge(pages[i], mm, 1054b9bbfbe3SAndrea Arcangeli GFP_KERNEL))) { 1055b9bbfbe3SAndrea Arcangeli if (pages[i]) 105671e3aac0SAndrea Arcangeli put_page(pages[i]); 1057b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_start(); 1058b9bbfbe3SAndrea Arcangeli while (--i >= 0) { 1059b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(pages[i]); 1060b9bbfbe3SAndrea Arcangeli put_page(pages[i]); 1061b9bbfbe3SAndrea Arcangeli } 1062b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_end(); 106371e3aac0SAndrea Arcangeli kfree(pages); 106471e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 106571e3aac0SAndrea Arcangeli goto out; 106671e3aac0SAndrea Arcangeli } 106771e3aac0SAndrea Arcangeli } 106871e3aac0SAndrea Arcangeli 106971e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 107071e3aac0SAndrea Arcangeli copy_user_highpage(pages[i], page + i, 10710089e485SHillf Danton haddr + PAGE_SIZE * i, vma); 107271e3aac0SAndrea Arcangeli __SetPageUptodate(pages[i]); 107371e3aac0SAndrea Arcangeli cond_resched(); 107471e3aac0SAndrea Arcangeli } 107571e3aac0SAndrea Arcangeli 10762ec74c3eSSagi Grimberg mmun_start = haddr; 10772ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 10782ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 10792ec74c3eSSagi Grimberg 108071e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 108171e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 108271e3aac0SAndrea Arcangeli goto out_free_pages; 108371e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 108471e3aac0SAndrea Arcangeli 10852ec74c3eSSagi Grimberg pmdp_clear_flush(vma, haddr, pmd); 108671e3aac0SAndrea Arcangeli /* leave pmd empty until pte is filled */ 108771e3aac0SAndrea Arcangeli 10886b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 108971e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 109071e3aac0SAndrea Arcangeli 109171e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 109271e3aac0SAndrea Arcangeli pte_t *pte, entry; 109371e3aac0SAndrea Arcangeli entry = mk_pte(pages[i], vma->vm_page_prot); 109471e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 109571e3aac0SAndrea Arcangeli page_add_new_anon_rmap(pages[i], vma, haddr); 109671e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 109771e3aac0SAndrea Arcangeli VM_BUG_ON(!pte_none(*pte)); 109871e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 109971e3aac0SAndrea Arcangeli pte_unmap(pte); 110071e3aac0SAndrea Arcangeli } 110171e3aac0SAndrea Arcangeli kfree(pages); 110271e3aac0SAndrea Arcangeli 110371e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 110471e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 110571e3aac0SAndrea Arcangeli page_remove_rmap(page); 110671e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 110771e3aac0SAndrea Arcangeli 11082ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 11092ec74c3eSSagi Grimberg 111071e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 111171e3aac0SAndrea Arcangeli put_page(page); 111271e3aac0SAndrea Arcangeli 111371e3aac0SAndrea Arcangeli out: 111471e3aac0SAndrea Arcangeli return ret; 111571e3aac0SAndrea Arcangeli 111671e3aac0SAndrea Arcangeli out_free_pages: 111771e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 11182ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 1119b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_start(); 1120b9bbfbe3SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 1121b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(pages[i]); 112271e3aac0SAndrea Arcangeli put_page(pages[i]); 1123b9bbfbe3SAndrea Arcangeli } 1124b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_end(); 112571e3aac0SAndrea Arcangeli kfree(pages); 112671e3aac0SAndrea Arcangeli goto out; 112771e3aac0SAndrea Arcangeli } 112871e3aac0SAndrea Arcangeli 112971e3aac0SAndrea Arcangeli int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 113071e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, pmd_t orig_pmd) 113171e3aac0SAndrea Arcangeli { 113271e3aac0SAndrea Arcangeli int ret = 0; 113393b4796dSKirill A. Shutemov struct page *page = NULL, *new_page; 113471e3aac0SAndrea Arcangeli unsigned long haddr; 11352ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 11362ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 113771e3aac0SAndrea Arcangeli 113871e3aac0SAndrea Arcangeli VM_BUG_ON(!vma->anon_vma); 113993b4796dSKirill A. Shutemov haddr = address & HPAGE_PMD_MASK; 114093b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 114193b4796dSKirill A. Shutemov goto alloc; 114271e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 114371e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 114471e3aac0SAndrea Arcangeli goto out_unlock; 114571e3aac0SAndrea Arcangeli 114671e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 114771e3aac0SAndrea Arcangeli VM_BUG_ON(!PageCompound(page) || !PageHead(page)); 114871e3aac0SAndrea Arcangeli if (page_mapcount(page) == 1) { 114971e3aac0SAndrea Arcangeli pmd_t entry; 115071e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 115171e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 115271e3aac0SAndrea Arcangeli if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) 1153b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 115471e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 115571e3aac0SAndrea Arcangeli goto out_unlock; 115671e3aac0SAndrea Arcangeli } 115771e3aac0SAndrea Arcangeli get_page(page); 115871e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 115993b4796dSKirill A. Shutemov alloc: 116071e3aac0SAndrea Arcangeli if (transparent_hugepage_enabled(vma) && 116171e3aac0SAndrea Arcangeli !transparent_hugepage_debug_cow()) 11620bbbc0b3SAndrea Arcangeli new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), 1163cc5d462fSAndi Kleen vma, haddr, numa_node_id(), 0); 116471e3aac0SAndrea Arcangeli else 116571e3aac0SAndrea Arcangeli new_page = NULL; 116671e3aac0SAndrea Arcangeli 116771e3aac0SAndrea Arcangeli if (unlikely(!new_page)) { 116881ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 116993b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) { 117093b4796dSKirill A. Shutemov ret = do_huge_pmd_wp_zero_page_fallback(mm, vma, 11713ea41e62SKirill A. Shutemov address, pmd, orig_pmd, haddr); 117293b4796dSKirill A. Shutemov } else { 117371e3aac0SAndrea Arcangeli ret = do_huge_pmd_wp_page_fallback(mm, vma, address, 117471e3aac0SAndrea Arcangeli pmd, orig_pmd, page, haddr); 11751f1d06c3SDavid Rientjes if (ret & VM_FAULT_OOM) 11761f1d06c3SDavid Rientjes split_huge_page(page); 117771e3aac0SAndrea Arcangeli put_page(page); 117893b4796dSKirill A. Shutemov } 117971e3aac0SAndrea Arcangeli goto out; 118071e3aac0SAndrea Arcangeli } 118181ab4201SAndi Kleen count_vm_event(THP_FAULT_ALLOC); 118271e3aac0SAndrea Arcangeli 1183b9bbfbe3SAndrea Arcangeli if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { 1184b9bbfbe3SAndrea Arcangeli put_page(new_page); 118593b4796dSKirill A. Shutemov if (page) { 11861f1d06c3SDavid Rientjes split_huge_page(page); 1187b9bbfbe3SAndrea Arcangeli put_page(page); 118893b4796dSKirill A. Shutemov } 1189b9bbfbe3SAndrea Arcangeli ret |= VM_FAULT_OOM; 1190b9bbfbe3SAndrea Arcangeli goto out; 1191b9bbfbe3SAndrea Arcangeli } 1192b9bbfbe3SAndrea Arcangeli 119393b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 119493b4796dSKirill A. Shutemov clear_huge_page(new_page, haddr, HPAGE_PMD_NR); 119593b4796dSKirill A. Shutemov else 119671e3aac0SAndrea Arcangeli copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); 119771e3aac0SAndrea Arcangeli __SetPageUptodate(new_page); 119871e3aac0SAndrea Arcangeli 11992ec74c3eSSagi Grimberg mmun_start = haddr; 12002ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 12012ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 12022ec74c3eSSagi Grimberg 120371e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 120493b4796dSKirill A. Shutemov if (page) 120571e3aac0SAndrea Arcangeli put_page(page); 1206b9bbfbe3SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) { 12076f60b69dSDavid Rientjes spin_unlock(&mm->page_table_lock); 1208b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(new_page); 120971e3aac0SAndrea Arcangeli put_page(new_page); 12102ec74c3eSSagi Grimberg goto out_mn; 1211b9bbfbe3SAndrea Arcangeli } else { 121271e3aac0SAndrea Arcangeli pmd_t entry; 1213*3122359aSKirill A. Shutemov entry = mk_huge_pmd(new_page, vma->vm_page_prot); 1214*3122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 12152ec74c3eSSagi Grimberg pmdp_clear_flush(vma, haddr, pmd); 121671e3aac0SAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, haddr); 121771e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 1218b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 121997ae1749SKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) { 122093b4796dSKirill A. Shutemov add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 122197ae1749SKirill A. Shutemov put_huge_zero_page(); 122297ae1749SKirill A. Shutemov } else { 122393b4796dSKirill A. Shutemov VM_BUG_ON(!PageHead(page)); 122471e3aac0SAndrea Arcangeli page_remove_rmap(page); 122571e3aac0SAndrea Arcangeli put_page(page); 122693b4796dSKirill A. Shutemov } 122771e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 122871e3aac0SAndrea Arcangeli } 12292ec74c3eSSagi Grimberg spin_unlock(&mm->page_table_lock); 12302ec74c3eSSagi Grimberg out_mn: 12312ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 12322ec74c3eSSagi Grimberg out: 12332ec74c3eSSagi Grimberg return ret; 123471e3aac0SAndrea Arcangeli out_unlock: 123571e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 123671e3aac0SAndrea Arcangeli return ret; 123771e3aac0SAndrea Arcangeli } 123871e3aac0SAndrea Arcangeli 1239b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 124071e3aac0SAndrea Arcangeli unsigned long addr, 124171e3aac0SAndrea Arcangeli pmd_t *pmd, 124271e3aac0SAndrea Arcangeli unsigned int flags) 124371e3aac0SAndrea Arcangeli { 1244b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 124571e3aac0SAndrea Arcangeli struct page *page = NULL; 124671e3aac0SAndrea Arcangeli 124771e3aac0SAndrea Arcangeli assert_spin_locked(&mm->page_table_lock); 124871e3aac0SAndrea Arcangeli 124971e3aac0SAndrea Arcangeli if (flags & FOLL_WRITE && !pmd_write(*pmd)) 125071e3aac0SAndrea Arcangeli goto out; 125171e3aac0SAndrea Arcangeli 125285facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 125385facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 125485facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 125585facf25SKirill A. Shutemov 125671e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 125771e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 125871e3aac0SAndrea Arcangeli if (flags & FOLL_TOUCH) { 125971e3aac0SAndrea Arcangeli pmd_t _pmd; 126071e3aac0SAndrea Arcangeli /* 126171e3aac0SAndrea Arcangeli * We should set the dirty bit only for FOLL_WRITE but 126271e3aac0SAndrea Arcangeli * for now the dirty bit in the pmd is meaningless. 126371e3aac0SAndrea Arcangeli * And if the dirty bit will become meaningful and 126471e3aac0SAndrea Arcangeli * we'll only set it with FOLL_WRITE, an atomic 126571e3aac0SAndrea Arcangeli * set_bit will be required on the pmd to set the 126671e3aac0SAndrea Arcangeli * young bit, instead of the current set_pmd_at. 126771e3aac0SAndrea Arcangeli */ 126871e3aac0SAndrea Arcangeli _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); 12698663890aSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 12708663890aSAneesh Kumar K.V pmd, _pmd, 1)) 12718663890aSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 127271e3aac0SAndrea Arcangeli } 1273b676b293SDavid Rientjes if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { 1274b676b293SDavid Rientjes if (page->mapping && trylock_page(page)) { 1275b676b293SDavid Rientjes lru_add_drain(); 1276b676b293SDavid Rientjes if (page->mapping) 1277b676b293SDavid Rientjes mlock_vma_page(page); 1278b676b293SDavid Rientjes unlock_page(page); 1279b676b293SDavid Rientjes } 1280b676b293SDavid Rientjes } 128171e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 128271e3aac0SAndrea Arcangeli VM_BUG_ON(!PageCompound(page)); 128371e3aac0SAndrea Arcangeli if (flags & FOLL_GET) 128470b50f94SAndrea Arcangeli get_page_foll(page); 128571e3aac0SAndrea Arcangeli 128671e3aac0SAndrea Arcangeli out: 128771e3aac0SAndrea Arcangeli return page; 128871e3aac0SAndrea Arcangeli } 128971e3aac0SAndrea Arcangeli 1290d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 12914daae3b4SMel Gorman int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, 12924daae3b4SMel Gorman unsigned long addr, pmd_t pmd, pmd_t *pmdp) 1293d10e63f2SMel Gorman { 1294b32967ffSMel Gorman struct page *page; 1295d10e63f2SMel Gorman unsigned long haddr = addr & HPAGE_PMD_MASK; 12964daae3b4SMel Gorman int target_nid; 129703c5a6e1SMel Gorman int current_nid = -1; 1298b32967ffSMel Gorman bool migrated; 1299d10e63f2SMel Gorman 1300d10e63f2SMel Gorman spin_lock(&mm->page_table_lock); 1301d10e63f2SMel Gorman if (unlikely(!pmd_same(pmd, *pmdp))) 1302d10e63f2SMel Gorman goto out_unlock; 1303d10e63f2SMel Gorman 1304d10e63f2SMel Gorman page = pmd_page(pmd); 13054daae3b4SMel Gorman get_page(page); 130603c5a6e1SMel Gorman current_nid = page_to_nid(page); 130703c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 130803c5a6e1SMel Gorman if (current_nid == numa_node_id()) 130903c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 13104daae3b4SMel Gorman 13114daae3b4SMel Gorman target_nid = mpol_misplaced(page, vma, haddr); 1312b32967ffSMel Gorman if (target_nid == -1) { 13134daae3b4SMel Gorman put_page(page); 1314b32967ffSMel Gorman goto clear_pmdnuma; 1315b32967ffSMel Gorman } 1316cbee9f88SPeter Zijlstra 1317b32967ffSMel Gorman /* Acquire the page lock to serialise THP migrations */ 1318b32967ffSMel Gorman spin_unlock(&mm->page_table_lock); 1319b32967ffSMel Gorman lock_page(page); 1320b32967ffSMel Gorman 1321b32967ffSMel Gorman /* Confirm the PTE did not while locked */ 1322b32967ffSMel Gorman spin_lock(&mm->page_table_lock); 1323b32967ffSMel Gorman if (unlikely(!pmd_same(pmd, *pmdp))) { 1324b32967ffSMel Gorman unlock_page(page); 1325b32967ffSMel Gorman put_page(page); 1326b32967ffSMel Gorman goto out_unlock; 1327b32967ffSMel Gorman } 1328b32967ffSMel Gorman spin_unlock(&mm->page_table_lock); 1329b32967ffSMel Gorman 1330b32967ffSMel Gorman /* Migrate the THP to the requested node */ 1331b32967ffSMel Gorman migrated = migrate_misplaced_transhuge_page(mm, vma, 1332340ef390SHugh Dickins pmdp, pmd, addr, page, target_nid); 1333340ef390SHugh Dickins if (!migrated) 1334340ef390SHugh Dickins goto check_same; 1335b32967ffSMel Gorman 1336340ef390SHugh Dickins task_numa_fault(target_nid, HPAGE_PMD_NR, true); 13374daae3b4SMel Gorman return 0; 13384daae3b4SMel Gorman 1339340ef390SHugh Dickins check_same: 1340340ef390SHugh Dickins spin_lock(&mm->page_table_lock); 1341340ef390SHugh Dickins if (unlikely(!pmd_same(pmd, *pmdp))) 1342340ef390SHugh Dickins goto out_unlock; 13434daae3b4SMel Gorman clear_pmdnuma: 1344d10e63f2SMel Gorman pmd = pmd_mknonnuma(pmd); 1345d10e63f2SMel Gorman set_pmd_at(mm, haddr, pmdp, pmd); 1346d10e63f2SMel Gorman VM_BUG_ON(pmd_numa(*pmdp)); 1347d10e63f2SMel Gorman update_mmu_cache_pmd(vma, addr, pmdp); 1348d10e63f2SMel Gorman out_unlock: 1349d10e63f2SMel Gorman spin_unlock(&mm->page_table_lock); 1350b32967ffSMel Gorman if (current_nid != -1) 1351340ef390SHugh Dickins task_numa_fault(current_nid, HPAGE_PMD_NR, false); 1352d10e63f2SMel Gorman return 0; 1353d10e63f2SMel Gorman } 1354d10e63f2SMel Gorman 135571e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1356f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 135771e3aac0SAndrea Arcangeli { 135871e3aac0SAndrea Arcangeli int ret = 0; 135971e3aac0SAndrea Arcangeli 1360025c5b24SNaoya Horiguchi if (__pmd_trans_huge_lock(pmd, vma) == 1) { 136171e3aac0SAndrea Arcangeli struct page *page; 136271e3aac0SAndrea Arcangeli pgtable_t pgtable; 1363f5c8ad47SDavid Miller pmd_t orig_pmd; 1364a6bf2bb0SAneesh Kumar K.V /* 1365a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 1366a6bf2bb0SAneesh Kumar K.V * when calling pmdp_get_and_clear. So do the 1367a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1368a6bf2bb0SAneesh Kumar K.V * operations. 1369a6bf2bb0SAneesh Kumar K.V */ 1370f5c8ad47SDavid Miller orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); 1371f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1372a6bf2bb0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); 1373479f0abbSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) { 1374479f0abbSKirill A. Shutemov tlb->mm->nr_ptes--; 1375479f0abbSKirill A. Shutemov spin_unlock(&tlb->mm->page_table_lock); 137697ae1749SKirill A. Shutemov put_huge_zero_page(); 1377479f0abbSKirill A. Shutemov } else { 1378479f0abbSKirill A. Shutemov page = pmd_page(orig_pmd); 137971e3aac0SAndrea Arcangeli page_remove_rmap(page); 138071e3aac0SAndrea Arcangeli VM_BUG_ON(page_mapcount(page) < 0); 138171e3aac0SAndrea Arcangeli add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 138271e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 13831c641e84SAndrea Arcangeli tlb->mm->nr_ptes--; 138471e3aac0SAndrea Arcangeli spin_unlock(&tlb->mm->page_table_lock); 138571e3aac0SAndrea Arcangeli tlb_remove_page(tlb, page); 1386479f0abbSKirill A. Shutemov } 138771e3aac0SAndrea Arcangeli pte_free(tlb->mm, pgtable); 138871e3aac0SAndrea Arcangeli ret = 1; 138971e3aac0SAndrea Arcangeli } 139071e3aac0SAndrea Arcangeli return ret; 139171e3aac0SAndrea Arcangeli } 139271e3aac0SAndrea Arcangeli 13930ca1634dSJohannes Weiner int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 13940ca1634dSJohannes Weiner unsigned long addr, unsigned long end, 13950ca1634dSJohannes Weiner unsigned char *vec) 13960ca1634dSJohannes Weiner { 13970ca1634dSJohannes Weiner int ret = 0; 13980ca1634dSJohannes Weiner 1399025c5b24SNaoya Horiguchi if (__pmd_trans_huge_lock(pmd, vma) == 1) { 14000ca1634dSJohannes Weiner /* 14010ca1634dSJohannes Weiner * All logical pages in the range are present 14020ca1634dSJohannes Weiner * if backed by a huge page. 14030ca1634dSJohannes Weiner */ 14040ca1634dSJohannes Weiner spin_unlock(&vma->vm_mm->page_table_lock); 1405025c5b24SNaoya Horiguchi memset(vec, 1, (end - addr) >> PAGE_SHIFT); 1406025c5b24SNaoya Horiguchi ret = 1; 1407025c5b24SNaoya Horiguchi } 14080ca1634dSJohannes Weiner 14090ca1634dSJohannes Weiner return ret; 14100ca1634dSJohannes Weiner } 14110ca1634dSJohannes Weiner 141237a1c49aSAndrea Arcangeli int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, 141337a1c49aSAndrea Arcangeli unsigned long old_addr, 141437a1c49aSAndrea Arcangeli unsigned long new_addr, unsigned long old_end, 141537a1c49aSAndrea Arcangeli pmd_t *old_pmd, pmd_t *new_pmd) 141637a1c49aSAndrea Arcangeli { 141737a1c49aSAndrea Arcangeli int ret = 0; 141837a1c49aSAndrea Arcangeli pmd_t pmd; 141937a1c49aSAndrea Arcangeli 142037a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 142137a1c49aSAndrea Arcangeli 142237a1c49aSAndrea Arcangeli if ((old_addr & ~HPAGE_PMD_MASK) || 142337a1c49aSAndrea Arcangeli (new_addr & ~HPAGE_PMD_MASK) || 142437a1c49aSAndrea Arcangeli old_end - old_addr < HPAGE_PMD_SIZE || 142537a1c49aSAndrea Arcangeli (new_vma->vm_flags & VM_NOHUGEPAGE)) 142637a1c49aSAndrea Arcangeli goto out; 142737a1c49aSAndrea Arcangeli 142837a1c49aSAndrea Arcangeli /* 142937a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 143037a1c49aSAndrea Arcangeli * should have release it. 143137a1c49aSAndrea Arcangeli */ 143237a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 143337a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 143437a1c49aSAndrea Arcangeli goto out; 143537a1c49aSAndrea Arcangeli } 143637a1c49aSAndrea Arcangeli 1437025c5b24SNaoya Horiguchi ret = __pmd_trans_huge_lock(old_pmd, vma); 1438025c5b24SNaoya Horiguchi if (ret == 1) { 143937a1c49aSAndrea Arcangeli pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); 144037a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 14410f8975ecSPavel Emelyanov set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); 144237a1c49aSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 144337a1c49aSAndrea Arcangeli } 144437a1c49aSAndrea Arcangeli out: 144537a1c49aSAndrea Arcangeli return ret; 144637a1c49aSAndrea Arcangeli } 144737a1c49aSAndrea Arcangeli 1448cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 14494b10e7d5SMel Gorman unsigned long addr, pgprot_t newprot, int prot_numa) 1450cd7548abSJohannes Weiner { 1451cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1452cd7548abSJohannes Weiner int ret = 0; 1453cd7548abSJohannes Weiner 1454025c5b24SNaoya Horiguchi if (__pmd_trans_huge_lock(pmd, vma) == 1) { 1455cd7548abSJohannes Weiner pmd_t entry; 1456cd7548abSJohannes Weiner entry = pmdp_get_and_clear(mm, addr, pmd); 1457a4f1de17SHugh Dickins if (!prot_numa) { 1458cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 1459a4f1de17SHugh Dickins BUG_ON(pmd_write(entry)); 1460a4f1de17SHugh Dickins } else { 14614b10e7d5SMel Gorman struct page *page = pmd_page(*pmd); 14624b10e7d5SMel Gorman 14634b10e7d5SMel Gorman /* only check non-shared pages */ 14644b10e7d5SMel Gorman if (page_mapcount(page) == 1 && 14654b10e7d5SMel Gorman !pmd_numa(*pmd)) { 14664b10e7d5SMel Gorman entry = pmd_mknuma(entry); 14674b10e7d5SMel Gorman } 14684b10e7d5SMel Gorman } 1469cd7548abSJohannes Weiner set_pmd_at(mm, addr, pmd, entry); 1470cd7548abSJohannes Weiner spin_unlock(&vma->vm_mm->page_table_lock); 1471cd7548abSJohannes Weiner ret = 1; 1472cd7548abSJohannes Weiner } 1473cd7548abSJohannes Weiner 1474cd7548abSJohannes Weiner return ret; 1475cd7548abSJohannes Weiner } 1476cd7548abSJohannes Weiner 1477025c5b24SNaoya Horiguchi /* 1478025c5b24SNaoya Horiguchi * Returns 1 if a given pmd maps a stable (not under splitting) thp. 1479025c5b24SNaoya Horiguchi * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. 1480025c5b24SNaoya Horiguchi * 1481025c5b24SNaoya Horiguchi * Note that if it returns 1, this routine returns without unlocking page 1482025c5b24SNaoya Horiguchi * table locks. So callers must unlock them. 1483025c5b24SNaoya Horiguchi */ 1484025c5b24SNaoya Horiguchi int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1485025c5b24SNaoya Horiguchi { 1486025c5b24SNaoya Horiguchi spin_lock(&vma->vm_mm->page_table_lock); 1487025c5b24SNaoya Horiguchi if (likely(pmd_trans_huge(*pmd))) { 1488025c5b24SNaoya Horiguchi if (unlikely(pmd_trans_splitting(*pmd))) { 1489025c5b24SNaoya Horiguchi spin_unlock(&vma->vm_mm->page_table_lock); 1490025c5b24SNaoya Horiguchi wait_split_huge_page(vma->anon_vma, pmd); 1491025c5b24SNaoya Horiguchi return -1; 1492025c5b24SNaoya Horiguchi } else { 1493025c5b24SNaoya Horiguchi /* Thp mapped by 'pmd' is stable, so we can 1494025c5b24SNaoya Horiguchi * handle it as it is. */ 1495025c5b24SNaoya Horiguchi return 1; 1496025c5b24SNaoya Horiguchi } 1497025c5b24SNaoya Horiguchi } 1498025c5b24SNaoya Horiguchi spin_unlock(&vma->vm_mm->page_table_lock); 1499025c5b24SNaoya Horiguchi return 0; 1500025c5b24SNaoya Horiguchi } 1501025c5b24SNaoya Horiguchi 150271e3aac0SAndrea Arcangeli pmd_t *page_check_address_pmd(struct page *page, 150371e3aac0SAndrea Arcangeli struct mm_struct *mm, 150471e3aac0SAndrea Arcangeli unsigned long address, 150571e3aac0SAndrea Arcangeli enum page_check_address_pmd_flag flag) 150671e3aac0SAndrea Arcangeli { 150771e3aac0SAndrea Arcangeli pmd_t *pmd, *ret = NULL; 150871e3aac0SAndrea Arcangeli 150971e3aac0SAndrea Arcangeli if (address & ~HPAGE_PMD_MASK) 151071e3aac0SAndrea Arcangeli goto out; 151171e3aac0SAndrea Arcangeli 15126219049aSBob Liu pmd = mm_find_pmd(mm, address); 15136219049aSBob Liu if (!pmd) 151471e3aac0SAndrea Arcangeli goto out; 151571e3aac0SAndrea Arcangeli if (pmd_none(*pmd)) 151671e3aac0SAndrea Arcangeli goto out; 151771e3aac0SAndrea Arcangeli if (pmd_page(*pmd) != page) 151871e3aac0SAndrea Arcangeli goto out; 151994fcc585SAndrea Arcangeli /* 152094fcc585SAndrea Arcangeli * split_vma() may create temporary aliased mappings. There is 152194fcc585SAndrea Arcangeli * no risk as long as all huge pmd are found and have their 152294fcc585SAndrea Arcangeli * splitting bit set before __split_huge_page_refcount 152394fcc585SAndrea Arcangeli * runs. Finding the same huge pmd more than once during the 152494fcc585SAndrea Arcangeli * same rmap walk is not a problem. 152594fcc585SAndrea Arcangeli */ 152694fcc585SAndrea Arcangeli if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && 152794fcc585SAndrea Arcangeli pmd_trans_splitting(*pmd)) 152894fcc585SAndrea Arcangeli goto out; 152971e3aac0SAndrea Arcangeli if (pmd_trans_huge(*pmd)) { 153071e3aac0SAndrea Arcangeli VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && 153171e3aac0SAndrea Arcangeli !pmd_trans_splitting(*pmd)); 153271e3aac0SAndrea Arcangeli ret = pmd; 153371e3aac0SAndrea Arcangeli } 153471e3aac0SAndrea Arcangeli out: 153571e3aac0SAndrea Arcangeli return ret; 153671e3aac0SAndrea Arcangeli } 153771e3aac0SAndrea Arcangeli 153871e3aac0SAndrea Arcangeli static int __split_huge_page_splitting(struct page *page, 153971e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 154071e3aac0SAndrea Arcangeli unsigned long address) 154171e3aac0SAndrea Arcangeli { 154271e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 154371e3aac0SAndrea Arcangeli pmd_t *pmd; 154471e3aac0SAndrea Arcangeli int ret = 0; 15452ec74c3eSSagi Grimberg /* For mmu_notifiers */ 15462ec74c3eSSagi Grimberg const unsigned long mmun_start = address; 15472ec74c3eSSagi Grimberg const unsigned long mmun_end = address + HPAGE_PMD_SIZE; 154871e3aac0SAndrea Arcangeli 15492ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 155071e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 155171e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 155271e3aac0SAndrea Arcangeli PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG); 155371e3aac0SAndrea Arcangeli if (pmd) { 155471e3aac0SAndrea Arcangeli /* 155571e3aac0SAndrea Arcangeli * We can't temporarily set the pmd to null in order 155671e3aac0SAndrea Arcangeli * to split it, the pmd must remain marked huge at all 155771e3aac0SAndrea Arcangeli * times or the VM won't take the pmd_trans_huge paths 15585a505085SIngo Molnar * and it won't wait on the anon_vma->root->rwsem to 155971e3aac0SAndrea Arcangeli * serialize against split_huge_page*. 156071e3aac0SAndrea Arcangeli */ 15612ec74c3eSSagi Grimberg pmdp_splitting_flush(vma, address, pmd); 156271e3aac0SAndrea Arcangeli ret = 1; 156371e3aac0SAndrea Arcangeli } 156471e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 15652ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 156671e3aac0SAndrea Arcangeli 156771e3aac0SAndrea Arcangeli return ret; 156871e3aac0SAndrea Arcangeli } 156971e3aac0SAndrea Arcangeli 15705bc7b8acSShaohua Li static void __split_huge_page_refcount(struct page *page, 15715bc7b8acSShaohua Li struct list_head *list) 157271e3aac0SAndrea Arcangeli { 157371e3aac0SAndrea Arcangeli int i; 157471e3aac0SAndrea Arcangeli struct zone *zone = page_zone(page); 1575fa9add64SHugh Dickins struct lruvec *lruvec; 157670b50f94SAndrea Arcangeli int tail_count = 0; 157771e3aac0SAndrea Arcangeli 157871e3aac0SAndrea Arcangeli /* prevent PageLRU to go away from under us, and freeze lru stats */ 157971e3aac0SAndrea Arcangeli spin_lock_irq(&zone->lru_lock); 1580fa9add64SHugh Dickins lruvec = mem_cgroup_page_lruvec(page, zone); 1581fa9add64SHugh Dickins 158271e3aac0SAndrea Arcangeli compound_lock(page); 1583e94c8a9cSKAMEZAWA Hiroyuki /* complete memcg works before add pages to LRU */ 1584e94c8a9cSKAMEZAWA Hiroyuki mem_cgroup_split_huge_fixup(page); 158571e3aac0SAndrea Arcangeli 158645676885SShaohua Li for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { 158771e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 158871e3aac0SAndrea Arcangeli 158970b50f94SAndrea Arcangeli /* tail_page->_mapcount cannot change */ 159070b50f94SAndrea Arcangeli BUG_ON(page_mapcount(page_tail) < 0); 159170b50f94SAndrea Arcangeli tail_count += page_mapcount(page_tail); 159270b50f94SAndrea Arcangeli /* check for overflow */ 159370b50f94SAndrea Arcangeli BUG_ON(tail_count < 0); 159470b50f94SAndrea Arcangeli BUG_ON(atomic_read(&page_tail->_count) != 0); 159570b50f94SAndrea Arcangeli /* 159670b50f94SAndrea Arcangeli * tail_page->_count is zero and not changing from 159770b50f94SAndrea Arcangeli * under us. But get_page_unless_zero() may be running 159870b50f94SAndrea Arcangeli * from under us on the tail_page. If we used 159970b50f94SAndrea Arcangeli * atomic_set() below instead of atomic_add(), we 160070b50f94SAndrea Arcangeli * would then run atomic_set() concurrently with 160170b50f94SAndrea Arcangeli * get_page_unless_zero(), and atomic_set() is 160270b50f94SAndrea Arcangeli * implemented in C not using locked ops. spin_unlock 160370b50f94SAndrea Arcangeli * on x86 sometime uses locked ops because of PPro 160470b50f94SAndrea Arcangeli * errata 66, 92, so unless somebody can guarantee 160570b50f94SAndrea Arcangeli * atomic_set() here would be safe on all archs (and 160670b50f94SAndrea Arcangeli * not only on x86), it's safer to use atomic_add(). 160770b50f94SAndrea Arcangeli */ 160870b50f94SAndrea Arcangeli atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, 160970b50f94SAndrea Arcangeli &page_tail->_count); 161071e3aac0SAndrea Arcangeli 161171e3aac0SAndrea Arcangeli /* after clearing PageTail the gup refcount can be released */ 161271e3aac0SAndrea Arcangeli smp_mb(); 161371e3aac0SAndrea Arcangeli 1614a6d30dddSJin Dongming /* 1615a6d30dddSJin Dongming * retain hwpoison flag of the poisoned tail page: 1616a6d30dddSJin Dongming * fix for the unsuitable process killed on Guest Machine(KVM) 1617a6d30dddSJin Dongming * by the memory-failure. 1618a6d30dddSJin Dongming */ 1619a6d30dddSJin Dongming page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; 162071e3aac0SAndrea Arcangeli page_tail->flags |= (page->flags & 162171e3aac0SAndrea Arcangeli ((1L << PG_referenced) | 162271e3aac0SAndrea Arcangeli (1L << PG_swapbacked) | 162371e3aac0SAndrea Arcangeli (1L << PG_mlocked) | 1624e180cf80SKirill A. Shutemov (1L << PG_uptodate) | 1625e180cf80SKirill A. Shutemov (1L << PG_active) | 1626e180cf80SKirill A. Shutemov (1L << PG_unevictable))); 162771e3aac0SAndrea Arcangeli page_tail->flags |= (1L << PG_dirty); 162871e3aac0SAndrea Arcangeli 162970b50f94SAndrea Arcangeli /* clear PageTail before overwriting first_page */ 163071e3aac0SAndrea Arcangeli smp_wmb(); 163171e3aac0SAndrea Arcangeli 163271e3aac0SAndrea Arcangeli /* 163371e3aac0SAndrea Arcangeli * __split_huge_page_splitting() already set the 163471e3aac0SAndrea Arcangeli * splitting bit in all pmd that could map this 163571e3aac0SAndrea Arcangeli * hugepage, that will ensure no CPU can alter the 163671e3aac0SAndrea Arcangeli * mapcount on the head page. The mapcount is only 163771e3aac0SAndrea Arcangeli * accounted in the head page and it has to be 163871e3aac0SAndrea Arcangeli * transferred to all tail pages in the below code. So 163971e3aac0SAndrea Arcangeli * for this code to be safe, the split the mapcount 164071e3aac0SAndrea Arcangeli * can't change. But that doesn't mean userland can't 164171e3aac0SAndrea Arcangeli * keep changing and reading the page contents while 164271e3aac0SAndrea Arcangeli * we transfer the mapcount, so the pmd splitting 164371e3aac0SAndrea Arcangeli * status is achieved setting a reserved bit in the 164471e3aac0SAndrea Arcangeli * pmd, not by clearing the present bit. 164571e3aac0SAndrea Arcangeli */ 164671e3aac0SAndrea Arcangeli page_tail->_mapcount = page->_mapcount; 164771e3aac0SAndrea Arcangeli 164871e3aac0SAndrea Arcangeli BUG_ON(page_tail->mapping); 164971e3aac0SAndrea Arcangeli page_tail->mapping = page->mapping; 165071e3aac0SAndrea Arcangeli 165145676885SShaohua Li page_tail->index = page->index + i; 165222b751c3SMel Gorman page_nid_xchg_last(page_tail, page_nid_last(page)); 165371e3aac0SAndrea Arcangeli 165471e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page_tail)); 165571e3aac0SAndrea Arcangeli BUG_ON(!PageUptodate(page_tail)); 165671e3aac0SAndrea Arcangeli BUG_ON(!PageDirty(page_tail)); 165771e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page_tail)); 165871e3aac0SAndrea Arcangeli 16595bc7b8acSShaohua Li lru_add_page_tail(page, page_tail, lruvec, list); 166071e3aac0SAndrea Arcangeli } 166170b50f94SAndrea Arcangeli atomic_sub(tail_count, &page->_count); 166270b50f94SAndrea Arcangeli BUG_ON(atomic_read(&page->_count) <= 0); 166371e3aac0SAndrea Arcangeli 1664fa9add64SHugh Dickins __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); 166579134171SAndrea Arcangeli 166671e3aac0SAndrea Arcangeli ClearPageCompound(page); 166771e3aac0SAndrea Arcangeli compound_unlock(page); 166871e3aac0SAndrea Arcangeli spin_unlock_irq(&zone->lru_lock); 166971e3aac0SAndrea Arcangeli 167071e3aac0SAndrea Arcangeli for (i = 1; i < HPAGE_PMD_NR; i++) { 167171e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 167271e3aac0SAndrea Arcangeli BUG_ON(page_count(page_tail) <= 0); 167371e3aac0SAndrea Arcangeli /* 167471e3aac0SAndrea Arcangeli * Tail pages may be freed if there wasn't any mapping 167571e3aac0SAndrea Arcangeli * like if add_to_swap() is running on a lru page that 167671e3aac0SAndrea Arcangeli * had its mapping zapped. And freeing these pages 167771e3aac0SAndrea Arcangeli * requires taking the lru_lock so we do the put_page 167871e3aac0SAndrea Arcangeli * of the tail pages after the split is complete. 167971e3aac0SAndrea Arcangeli */ 168071e3aac0SAndrea Arcangeli put_page(page_tail); 168171e3aac0SAndrea Arcangeli } 168271e3aac0SAndrea Arcangeli 168371e3aac0SAndrea Arcangeli /* 168471e3aac0SAndrea Arcangeli * Only the head page (now become a regular page) is required 168571e3aac0SAndrea Arcangeli * to be pinned by the caller. 168671e3aac0SAndrea Arcangeli */ 168771e3aac0SAndrea Arcangeli BUG_ON(page_count(page) <= 0); 168871e3aac0SAndrea Arcangeli } 168971e3aac0SAndrea Arcangeli 169071e3aac0SAndrea Arcangeli static int __split_huge_page_map(struct page *page, 169171e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 169271e3aac0SAndrea Arcangeli unsigned long address) 169371e3aac0SAndrea Arcangeli { 169471e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 169571e3aac0SAndrea Arcangeli pmd_t *pmd, _pmd; 169671e3aac0SAndrea Arcangeli int ret = 0, i; 169771e3aac0SAndrea Arcangeli pgtable_t pgtable; 169871e3aac0SAndrea Arcangeli unsigned long haddr; 169971e3aac0SAndrea Arcangeli 170071e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 170171e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 170271e3aac0SAndrea Arcangeli PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); 170371e3aac0SAndrea Arcangeli if (pmd) { 17046b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 170571e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 170671e3aac0SAndrea Arcangeli 1707e3ebcf64SGerald Schaefer haddr = address; 1708e3ebcf64SGerald Schaefer for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 170971e3aac0SAndrea Arcangeli pte_t *pte, entry; 171071e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page+i)); 171171e3aac0SAndrea Arcangeli entry = mk_pte(page + i, vma->vm_page_prot); 171271e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 171371e3aac0SAndrea Arcangeli if (!pmd_write(*pmd)) 171471e3aac0SAndrea Arcangeli entry = pte_wrprotect(entry); 171571e3aac0SAndrea Arcangeli else 171671e3aac0SAndrea Arcangeli BUG_ON(page_mapcount(page) != 1); 171771e3aac0SAndrea Arcangeli if (!pmd_young(*pmd)) 171871e3aac0SAndrea Arcangeli entry = pte_mkold(entry); 17191ba6e0b5SAndrea Arcangeli if (pmd_numa(*pmd)) 17201ba6e0b5SAndrea Arcangeli entry = pte_mknuma(entry); 172171e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 172271e3aac0SAndrea Arcangeli BUG_ON(!pte_none(*pte)); 172371e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 172471e3aac0SAndrea Arcangeli pte_unmap(pte); 172571e3aac0SAndrea Arcangeli } 172671e3aac0SAndrea Arcangeli 172771e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 172871e3aac0SAndrea Arcangeli /* 172971e3aac0SAndrea Arcangeli * Up to this point the pmd is present and huge and 173071e3aac0SAndrea Arcangeli * userland has the whole access to the hugepage 173171e3aac0SAndrea Arcangeli * during the split (which happens in place). If we 173271e3aac0SAndrea Arcangeli * overwrite the pmd with the not-huge version 173371e3aac0SAndrea Arcangeli * pointing to the pte here (which of course we could 173471e3aac0SAndrea Arcangeli * if all CPUs were bug free), userland could trigger 173571e3aac0SAndrea Arcangeli * a small page size TLB miss on the small sized TLB 173671e3aac0SAndrea Arcangeli * while the hugepage TLB entry is still established 173771e3aac0SAndrea Arcangeli * in the huge TLB. Some CPU doesn't like that. See 173871e3aac0SAndrea Arcangeli * http://support.amd.com/us/Processor_TechDocs/41322.pdf, 173971e3aac0SAndrea Arcangeli * Erratum 383 on page 93. Intel should be safe but is 174071e3aac0SAndrea Arcangeli * also warns that it's only safe if the permission 174171e3aac0SAndrea Arcangeli * and cache attributes of the two entries loaded in 174271e3aac0SAndrea Arcangeli * the two TLB is identical (which should be the case 174371e3aac0SAndrea Arcangeli * here). But it is generally safer to never allow 174471e3aac0SAndrea Arcangeli * small and huge TLB entries for the same virtual 174571e3aac0SAndrea Arcangeli * address to be loaded simultaneously. So instead of 174671e3aac0SAndrea Arcangeli * doing "pmd_populate(); flush_tlb_range();" we first 174771e3aac0SAndrea Arcangeli * mark the current pmd notpresent (atomically because 174871e3aac0SAndrea Arcangeli * here the pmd_trans_huge and pmd_trans_splitting 174971e3aac0SAndrea Arcangeli * must remain set at all times on the pmd until the 175071e3aac0SAndrea Arcangeli * split is complete for this pmd), then we flush the 175171e3aac0SAndrea Arcangeli * SMP TLB and finally we write the non-huge version 175271e3aac0SAndrea Arcangeli * of the pmd entry with pmd_populate. 175371e3aac0SAndrea Arcangeli */ 175446dcde73SGerald Schaefer pmdp_invalidate(vma, address, pmd); 175571e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 175671e3aac0SAndrea Arcangeli ret = 1; 175771e3aac0SAndrea Arcangeli } 175871e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 175971e3aac0SAndrea Arcangeli 176071e3aac0SAndrea Arcangeli return ret; 176171e3aac0SAndrea Arcangeli } 176271e3aac0SAndrea Arcangeli 17635a505085SIngo Molnar /* must be called with anon_vma->root->rwsem held */ 176471e3aac0SAndrea Arcangeli static void __split_huge_page(struct page *page, 17655bc7b8acSShaohua Li struct anon_vma *anon_vma, 17665bc7b8acSShaohua Li struct list_head *list) 176771e3aac0SAndrea Arcangeli { 176871e3aac0SAndrea Arcangeli int mapcount, mapcount2; 1769bf181b9fSMichel Lespinasse pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); 177071e3aac0SAndrea Arcangeli struct anon_vma_chain *avc; 177171e3aac0SAndrea Arcangeli 177271e3aac0SAndrea Arcangeli BUG_ON(!PageHead(page)); 177371e3aac0SAndrea Arcangeli BUG_ON(PageTail(page)); 177471e3aac0SAndrea Arcangeli 177571e3aac0SAndrea Arcangeli mapcount = 0; 1776bf181b9fSMichel Lespinasse anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { 177771e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 177871e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 177971e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 178071e3aac0SAndrea Arcangeli mapcount += __split_huge_page_splitting(page, vma, addr); 178171e3aac0SAndrea Arcangeli } 178205759d38SAndrea Arcangeli /* 178305759d38SAndrea Arcangeli * It is critical that new vmas are added to the tail of the 178405759d38SAndrea Arcangeli * anon_vma list. This guarantes that if copy_huge_pmd() runs 178505759d38SAndrea Arcangeli * and establishes a child pmd before 178605759d38SAndrea Arcangeli * __split_huge_page_splitting() freezes the parent pmd (so if 178705759d38SAndrea Arcangeli * we fail to prevent copy_huge_pmd() from running until the 178805759d38SAndrea Arcangeli * whole __split_huge_page() is complete), we will still see 178905759d38SAndrea Arcangeli * the newly established pmd of the child later during the 179005759d38SAndrea Arcangeli * walk, to be able to set it as pmd_trans_splitting too. 179105759d38SAndrea Arcangeli */ 179205759d38SAndrea Arcangeli if (mapcount != page_mapcount(page)) 179305759d38SAndrea Arcangeli printk(KERN_ERR "mapcount %d page_mapcount %d\n", 179405759d38SAndrea Arcangeli mapcount, page_mapcount(page)); 179571e3aac0SAndrea Arcangeli BUG_ON(mapcount != page_mapcount(page)); 179671e3aac0SAndrea Arcangeli 17975bc7b8acSShaohua Li __split_huge_page_refcount(page, list); 179871e3aac0SAndrea Arcangeli 179971e3aac0SAndrea Arcangeli mapcount2 = 0; 1800bf181b9fSMichel Lespinasse anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { 180171e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 180271e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 180371e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 180471e3aac0SAndrea Arcangeli mapcount2 += __split_huge_page_map(page, vma, addr); 180571e3aac0SAndrea Arcangeli } 180605759d38SAndrea Arcangeli if (mapcount != mapcount2) 180705759d38SAndrea Arcangeli printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", 180805759d38SAndrea Arcangeli mapcount, mapcount2, page_mapcount(page)); 180971e3aac0SAndrea Arcangeli BUG_ON(mapcount != mapcount2); 181071e3aac0SAndrea Arcangeli } 181171e3aac0SAndrea Arcangeli 18125bc7b8acSShaohua Li /* 18135bc7b8acSShaohua Li * Split a hugepage into normal pages. This doesn't change the position of head 18145bc7b8acSShaohua Li * page. If @list is null, tail pages will be added to LRU list, otherwise, to 18155bc7b8acSShaohua Li * @list. Both head page and tail pages will inherit mapping, flags, and so on 18165bc7b8acSShaohua Li * from the hugepage. 18175bc7b8acSShaohua Li * Return 0 if the hugepage is split successfully otherwise return 1. 18185bc7b8acSShaohua Li */ 18195bc7b8acSShaohua Li int split_huge_page_to_list(struct page *page, struct list_head *list) 182071e3aac0SAndrea Arcangeli { 182171e3aac0SAndrea Arcangeli struct anon_vma *anon_vma; 182271e3aac0SAndrea Arcangeli int ret = 1; 182371e3aac0SAndrea Arcangeli 18245918d10aSKirill A. Shutemov BUG_ON(is_huge_zero_page(page)); 182571e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page)); 1826062f1af2SMel Gorman 1827062f1af2SMel Gorman /* 1828062f1af2SMel Gorman * The caller does not necessarily hold an mmap_sem that would prevent 1829062f1af2SMel Gorman * the anon_vma disappearing so we first we take a reference to it 1830062f1af2SMel Gorman * and then lock the anon_vma for write. This is similar to 1831062f1af2SMel Gorman * page_lock_anon_vma_read except the write lock is taken to serialise 1832062f1af2SMel Gorman * against parallel split or collapse operations. 1833062f1af2SMel Gorman */ 1834062f1af2SMel Gorman anon_vma = page_get_anon_vma(page); 183571e3aac0SAndrea Arcangeli if (!anon_vma) 183671e3aac0SAndrea Arcangeli goto out; 1837062f1af2SMel Gorman anon_vma_lock_write(anon_vma); 1838062f1af2SMel Gorman 183971e3aac0SAndrea Arcangeli ret = 0; 184071e3aac0SAndrea Arcangeli if (!PageCompound(page)) 184171e3aac0SAndrea Arcangeli goto out_unlock; 184271e3aac0SAndrea Arcangeli 184371e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page)); 18445bc7b8acSShaohua Li __split_huge_page(page, anon_vma, list); 184581ab4201SAndi Kleen count_vm_event(THP_SPLIT); 184671e3aac0SAndrea Arcangeli 184771e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page)); 184871e3aac0SAndrea Arcangeli out_unlock: 184908b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 1850062f1af2SMel Gorman put_anon_vma(anon_vma); 185171e3aac0SAndrea Arcangeli out: 185271e3aac0SAndrea Arcangeli return ret; 185371e3aac0SAndrea Arcangeli } 185471e3aac0SAndrea Arcangeli 18554b6e1e37SKonstantin Khlebnikov #define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE) 185678f11a25SAndrea Arcangeli 185760ab3244SAndrea Arcangeli int hugepage_madvise(struct vm_area_struct *vma, 185860ab3244SAndrea Arcangeli unsigned long *vm_flags, int advice) 18590af4e98bSAndrea Arcangeli { 18608e72033fSGerald Schaefer struct mm_struct *mm = vma->vm_mm; 18618e72033fSGerald Schaefer 1862a664b2d8SAndrea Arcangeli switch (advice) { 1863a664b2d8SAndrea Arcangeli case MADV_HUGEPAGE: 18640af4e98bSAndrea Arcangeli /* 18650af4e98bSAndrea Arcangeli * Be somewhat over-protective like KSM for now! 18660af4e98bSAndrea Arcangeli */ 186778f11a25SAndrea Arcangeli if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) 18680af4e98bSAndrea Arcangeli return -EINVAL; 18698e72033fSGerald Schaefer if (mm->def_flags & VM_NOHUGEPAGE) 18708e72033fSGerald Schaefer return -EINVAL; 1871a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_NOHUGEPAGE; 18720af4e98bSAndrea Arcangeli *vm_flags |= VM_HUGEPAGE; 187360ab3244SAndrea Arcangeli /* 187460ab3244SAndrea Arcangeli * If the vma become good for khugepaged to scan, 187560ab3244SAndrea Arcangeli * register it here without waiting a page fault that 187660ab3244SAndrea Arcangeli * may not happen any time soon. 187760ab3244SAndrea Arcangeli */ 187860ab3244SAndrea Arcangeli if (unlikely(khugepaged_enter_vma_merge(vma))) 187960ab3244SAndrea Arcangeli return -ENOMEM; 1880a664b2d8SAndrea Arcangeli break; 1881a664b2d8SAndrea Arcangeli case MADV_NOHUGEPAGE: 1882a664b2d8SAndrea Arcangeli /* 1883a664b2d8SAndrea Arcangeli * Be somewhat over-protective like KSM for now! 1884a664b2d8SAndrea Arcangeli */ 188578f11a25SAndrea Arcangeli if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) 1886a664b2d8SAndrea Arcangeli return -EINVAL; 1887a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_HUGEPAGE; 1888a664b2d8SAndrea Arcangeli *vm_flags |= VM_NOHUGEPAGE; 188960ab3244SAndrea Arcangeli /* 189060ab3244SAndrea Arcangeli * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning 189160ab3244SAndrea Arcangeli * this vma even if we leave the mm registered in khugepaged if 189260ab3244SAndrea Arcangeli * it got registered before VM_NOHUGEPAGE was set. 189360ab3244SAndrea Arcangeli */ 1894a664b2d8SAndrea Arcangeli break; 1895a664b2d8SAndrea Arcangeli } 18960af4e98bSAndrea Arcangeli 18970af4e98bSAndrea Arcangeli return 0; 18980af4e98bSAndrea Arcangeli } 18990af4e98bSAndrea Arcangeli 1900ba76149fSAndrea Arcangeli static int __init khugepaged_slab_init(void) 1901ba76149fSAndrea Arcangeli { 1902ba76149fSAndrea Arcangeli mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", 1903ba76149fSAndrea Arcangeli sizeof(struct mm_slot), 1904ba76149fSAndrea Arcangeli __alignof__(struct mm_slot), 0, NULL); 1905ba76149fSAndrea Arcangeli if (!mm_slot_cache) 1906ba76149fSAndrea Arcangeli return -ENOMEM; 1907ba76149fSAndrea Arcangeli 1908ba76149fSAndrea Arcangeli return 0; 1909ba76149fSAndrea Arcangeli } 1910ba76149fSAndrea Arcangeli 1911ba76149fSAndrea Arcangeli static inline struct mm_slot *alloc_mm_slot(void) 1912ba76149fSAndrea Arcangeli { 1913ba76149fSAndrea Arcangeli if (!mm_slot_cache) /* initialization failed */ 1914ba76149fSAndrea Arcangeli return NULL; 1915ba76149fSAndrea Arcangeli return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); 1916ba76149fSAndrea Arcangeli } 1917ba76149fSAndrea Arcangeli 1918ba76149fSAndrea Arcangeli static inline void free_mm_slot(struct mm_slot *mm_slot) 1919ba76149fSAndrea Arcangeli { 1920ba76149fSAndrea Arcangeli kmem_cache_free(mm_slot_cache, mm_slot); 1921ba76149fSAndrea Arcangeli } 1922ba76149fSAndrea Arcangeli 1923ba76149fSAndrea Arcangeli static struct mm_slot *get_mm_slot(struct mm_struct *mm) 1924ba76149fSAndrea Arcangeli { 1925ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1926ba76149fSAndrea Arcangeli 1927b67bfe0dSSasha Levin hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm) 1928ba76149fSAndrea Arcangeli if (mm == mm_slot->mm) 1929ba76149fSAndrea Arcangeli return mm_slot; 193043b5fbbdSSasha Levin 1931ba76149fSAndrea Arcangeli return NULL; 1932ba76149fSAndrea Arcangeli } 1933ba76149fSAndrea Arcangeli 1934ba76149fSAndrea Arcangeli static void insert_to_mm_slots_hash(struct mm_struct *mm, 1935ba76149fSAndrea Arcangeli struct mm_slot *mm_slot) 1936ba76149fSAndrea Arcangeli { 1937ba76149fSAndrea Arcangeli mm_slot->mm = mm; 193843b5fbbdSSasha Levin hash_add(mm_slots_hash, &mm_slot->hash, (long)mm); 1939ba76149fSAndrea Arcangeli } 1940ba76149fSAndrea Arcangeli 1941ba76149fSAndrea Arcangeli static inline int khugepaged_test_exit(struct mm_struct *mm) 1942ba76149fSAndrea Arcangeli { 1943ba76149fSAndrea Arcangeli return atomic_read(&mm->mm_users) == 0; 1944ba76149fSAndrea Arcangeli } 1945ba76149fSAndrea Arcangeli 1946ba76149fSAndrea Arcangeli int __khugepaged_enter(struct mm_struct *mm) 1947ba76149fSAndrea Arcangeli { 1948ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1949ba76149fSAndrea Arcangeli int wakeup; 1950ba76149fSAndrea Arcangeli 1951ba76149fSAndrea Arcangeli mm_slot = alloc_mm_slot(); 1952ba76149fSAndrea Arcangeli if (!mm_slot) 1953ba76149fSAndrea Arcangeli return -ENOMEM; 1954ba76149fSAndrea Arcangeli 1955ba76149fSAndrea Arcangeli /* __khugepaged_exit() must not run from under us */ 1956ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_test_exit(mm)); 1957ba76149fSAndrea Arcangeli if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { 1958ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 1959ba76149fSAndrea Arcangeli return 0; 1960ba76149fSAndrea Arcangeli } 1961ba76149fSAndrea Arcangeli 1962ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 1963ba76149fSAndrea Arcangeli insert_to_mm_slots_hash(mm, mm_slot); 1964ba76149fSAndrea Arcangeli /* 1965ba76149fSAndrea Arcangeli * Insert just behind the scanning cursor, to let the area settle 1966ba76149fSAndrea Arcangeli * down a little. 1967ba76149fSAndrea Arcangeli */ 1968ba76149fSAndrea Arcangeli wakeup = list_empty(&khugepaged_scan.mm_head); 1969ba76149fSAndrea Arcangeli list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); 1970ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 1971ba76149fSAndrea Arcangeli 1972ba76149fSAndrea Arcangeli atomic_inc(&mm->mm_count); 1973ba76149fSAndrea Arcangeli if (wakeup) 1974ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 1975ba76149fSAndrea Arcangeli 1976ba76149fSAndrea Arcangeli return 0; 1977ba76149fSAndrea Arcangeli } 1978ba76149fSAndrea Arcangeli 1979ba76149fSAndrea Arcangeli int khugepaged_enter_vma_merge(struct vm_area_struct *vma) 1980ba76149fSAndrea Arcangeli { 1981ba76149fSAndrea Arcangeli unsigned long hstart, hend; 1982ba76149fSAndrea Arcangeli if (!vma->anon_vma) 1983ba76149fSAndrea Arcangeli /* 1984ba76149fSAndrea Arcangeli * Not yet faulted in so we will register later in the 1985ba76149fSAndrea Arcangeli * page fault if needed. 1986ba76149fSAndrea Arcangeli */ 1987ba76149fSAndrea Arcangeli return 0; 198878f11a25SAndrea Arcangeli if (vma->vm_ops) 1989ba76149fSAndrea Arcangeli /* khugepaged not yet working on file or special mappings */ 1990ba76149fSAndrea Arcangeli return 0; 1991b3b9c293SKonstantin Khlebnikov VM_BUG_ON(vma->vm_flags & VM_NO_THP); 1992ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 1993ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 1994ba76149fSAndrea Arcangeli if (hstart < hend) 1995ba76149fSAndrea Arcangeli return khugepaged_enter(vma); 1996ba76149fSAndrea Arcangeli return 0; 1997ba76149fSAndrea Arcangeli } 1998ba76149fSAndrea Arcangeli 1999ba76149fSAndrea Arcangeli void __khugepaged_exit(struct mm_struct *mm) 2000ba76149fSAndrea Arcangeli { 2001ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2002ba76149fSAndrea Arcangeli int free = 0; 2003ba76149fSAndrea Arcangeli 2004ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2005ba76149fSAndrea Arcangeli mm_slot = get_mm_slot(mm); 2006ba76149fSAndrea Arcangeli if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { 200743b5fbbdSSasha Levin hash_del(&mm_slot->hash); 2008ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 2009ba76149fSAndrea Arcangeli free = 1; 2010ba76149fSAndrea Arcangeli } 2011d788e80aSChris Wright spin_unlock(&khugepaged_mm_lock); 2012ba76149fSAndrea Arcangeli 2013ba76149fSAndrea Arcangeli if (free) { 2014ba76149fSAndrea Arcangeli clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 2015ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2016ba76149fSAndrea Arcangeli mmdrop(mm); 2017ba76149fSAndrea Arcangeli } else if (mm_slot) { 2018ba76149fSAndrea Arcangeli /* 2019ba76149fSAndrea Arcangeli * This is required to serialize against 2020ba76149fSAndrea Arcangeli * khugepaged_test_exit() (which is guaranteed to run 2021ba76149fSAndrea Arcangeli * under mmap sem read mode). Stop here (after we 2022ba76149fSAndrea Arcangeli * return all pagetables will be destroyed) until 2023ba76149fSAndrea Arcangeli * khugepaged has finished working on the pagetables 2024ba76149fSAndrea Arcangeli * under the mmap_sem. 2025ba76149fSAndrea Arcangeli */ 2026ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 2027ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 2028d788e80aSChris Wright } 2029ba76149fSAndrea Arcangeli } 2030ba76149fSAndrea Arcangeli 2031ba76149fSAndrea Arcangeli static void release_pte_page(struct page *page) 2032ba76149fSAndrea Arcangeli { 2033ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 2034ba76149fSAndrea Arcangeli dec_zone_page_state(page, NR_ISOLATED_ANON + 0); 2035ba76149fSAndrea Arcangeli unlock_page(page); 2036ba76149fSAndrea Arcangeli putback_lru_page(page); 2037ba76149fSAndrea Arcangeli } 2038ba76149fSAndrea Arcangeli 2039ba76149fSAndrea Arcangeli static void release_pte_pages(pte_t *pte, pte_t *_pte) 2040ba76149fSAndrea Arcangeli { 2041ba76149fSAndrea Arcangeli while (--_pte >= pte) { 2042ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2043ba76149fSAndrea Arcangeli if (!pte_none(pteval)) 2044ba76149fSAndrea Arcangeli release_pte_page(pte_page(pteval)); 2045ba76149fSAndrea Arcangeli } 2046ba76149fSAndrea Arcangeli } 2047ba76149fSAndrea Arcangeli 2048ba76149fSAndrea Arcangeli static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 2049ba76149fSAndrea Arcangeli unsigned long address, 2050ba76149fSAndrea Arcangeli pte_t *pte) 2051ba76149fSAndrea Arcangeli { 2052ba76149fSAndrea Arcangeli struct page *page; 2053ba76149fSAndrea Arcangeli pte_t *_pte; 2054344aa35cSBob Liu int referenced = 0, none = 0; 2055ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; 2056ba76149fSAndrea Arcangeli _pte++, address += PAGE_SIZE) { 2057ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2058ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 2059ba76149fSAndrea Arcangeli if (++none <= khugepaged_max_ptes_none) 2060ba76149fSAndrea Arcangeli continue; 2061344aa35cSBob Liu else 2062ba76149fSAndrea Arcangeli goto out; 2063ba76149fSAndrea Arcangeli } 2064344aa35cSBob Liu if (!pte_present(pteval) || !pte_write(pteval)) 2065ba76149fSAndrea Arcangeli goto out; 2066ba76149fSAndrea Arcangeli page = vm_normal_page(vma, address, pteval); 2067344aa35cSBob Liu if (unlikely(!page)) 2068ba76149fSAndrea Arcangeli goto out; 2069344aa35cSBob Liu 2070ba76149fSAndrea Arcangeli VM_BUG_ON(PageCompound(page)); 2071ba76149fSAndrea Arcangeli BUG_ON(!PageAnon(page)); 2072ba76149fSAndrea Arcangeli VM_BUG_ON(!PageSwapBacked(page)); 2073ba76149fSAndrea Arcangeli 2074ba76149fSAndrea Arcangeli /* cannot use mapcount: can't collapse if there's a gup pin */ 2075344aa35cSBob Liu if (page_count(page) != 1) 2076ba76149fSAndrea Arcangeli goto out; 2077ba76149fSAndrea Arcangeli /* 2078ba76149fSAndrea Arcangeli * We can do it before isolate_lru_page because the 2079ba76149fSAndrea Arcangeli * page can't be freed from under us. NOTE: PG_lock 2080ba76149fSAndrea Arcangeli * is needed to serialize against split_huge_page 2081ba76149fSAndrea Arcangeli * when invoked from the VM. 2082ba76149fSAndrea Arcangeli */ 2083344aa35cSBob Liu if (!trylock_page(page)) 2084ba76149fSAndrea Arcangeli goto out; 2085ba76149fSAndrea Arcangeli /* 2086ba76149fSAndrea Arcangeli * Isolate the page to avoid collapsing an hugepage 2087ba76149fSAndrea Arcangeli * currently in use by the VM. 2088ba76149fSAndrea Arcangeli */ 2089ba76149fSAndrea Arcangeli if (isolate_lru_page(page)) { 2090ba76149fSAndrea Arcangeli unlock_page(page); 2091ba76149fSAndrea Arcangeli goto out; 2092ba76149fSAndrea Arcangeli } 2093ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 2094ba76149fSAndrea Arcangeli inc_zone_page_state(page, NR_ISOLATED_ANON + 0); 2095ba76149fSAndrea Arcangeli VM_BUG_ON(!PageLocked(page)); 2096ba76149fSAndrea Arcangeli VM_BUG_ON(PageLRU(page)); 2097ba76149fSAndrea Arcangeli 2098ba76149fSAndrea Arcangeli /* If there is no mapped pte young don't collapse the page */ 20998ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 21008ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 2101ba76149fSAndrea Arcangeli referenced = 1; 2102ba76149fSAndrea Arcangeli } 2103344aa35cSBob Liu if (likely(referenced)) 2104344aa35cSBob Liu return 1; 2105ba76149fSAndrea Arcangeli out: 2106344aa35cSBob Liu release_pte_pages(pte, _pte); 2107344aa35cSBob Liu return 0; 2108ba76149fSAndrea Arcangeli } 2109ba76149fSAndrea Arcangeli 2110ba76149fSAndrea Arcangeli static void __collapse_huge_page_copy(pte_t *pte, struct page *page, 2111ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 2112ba76149fSAndrea Arcangeli unsigned long address, 2113ba76149fSAndrea Arcangeli spinlock_t *ptl) 2114ba76149fSAndrea Arcangeli { 2115ba76149fSAndrea Arcangeli pte_t *_pte; 2116ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { 2117ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2118ba76149fSAndrea Arcangeli struct page *src_page; 2119ba76149fSAndrea Arcangeli 2120ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 2121ba76149fSAndrea Arcangeli clear_user_highpage(page, address); 2122ba76149fSAndrea Arcangeli add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); 2123ba76149fSAndrea Arcangeli } else { 2124ba76149fSAndrea Arcangeli src_page = pte_page(pteval); 2125ba76149fSAndrea Arcangeli copy_user_highpage(page, src_page, address, vma); 2126ba76149fSAndrea Arcangeli VM_BUG_ON(page_mapcount(src_page) != 1); 2127ba76149fSAndrea Arcangeli release_pte_page(src_page); 2128ba76149fSAndrea Arcangeli /* 2129ba76149fSAndrea Arcangeli * ptl mostly unnecessary, but preempt has to 2130ba76149fSAndrea Arcangeli * be disabled to update the per-cpu stats 2131ba76149fSAndrea Arcangeli * inside page_remove_rmap(). 2132ba76149fSAndrea Arcangeli */ 2133ba76149fSAndrea Arcangeli spin_lock(ptl); 2134ba76149fSAndrea Arcangeli /* 2135ba76149fSAndrea Arcangeli * paravirt calls inside pte_clear here are 2136ba76149fSAndrea Arcangeli * superfluous. 2137ba76149fSAndrea Arcangeli */ 2138ba76149fSAndrea Arcangeli pte_clear(vma->vm_mm, address, _pte); 2139ba76149fSAndrea Arcangeli page_remove_rmap(src_page); 2140ba76149fSAndrea Arcangeli spin_unlock(ptl); 2141ba76149fSAndrea Arcangeli free_page_and_swap_cache(src_page); 2142ba76149fSAndrea Arcangeli } 2143ba76149fSAndrea Arcangeli 2144ba76149fSAndrea Arcangeli address += PAGE_SIZE; 2145ba76149fSAndrea Arcangeli page++; 2146ba76149fSAndrea Arcangeli } 2147ba76149fSAndrea Arcangeli } 2148ba76149fSAndrea Arcangeli 214926234f36SXiao Guangrong static void khugepaged_alloc_sleep(void) 215026234f36SXiao Guangrong { 215126234f36SXiao Guangrong wait_event_freezable_timeout(khugepaged_wait, false, 215226234f36SXiao Guangrong msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); 215326234f36SXiao Guangrong } 215426234f36SXiao Guangrong 215526234f36SXiao Guangrong #ifdef CONFIG_NUMA 215626234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 215726234f36SXiao Guangrong { 215826234f36SXiao Guangrong if (IS_ERR(*hpage)) { 215926234f36SXiao Guangrong if (!*wait) 216026234f36SXiao Guangrong return false; 216126234f36SXiao Guangrong 216226234f36SXiao Guangrong *wait = false; 2163e3b4126cSXiao Guangrong *hpage = NULL; 216426234f36SXiao Guangrong khugepaged_alloc_sleep(); 216526234f36SXiao Guangrong } else if (*hpage) { 216626234f36SXiao Guangrong put_page(*hpage); 216726234f36SXiao Guangrong *hpage = NULL; 216826234f36SXiao Guangrong } 216926234f36SXiao Guangrong 217026234f36SXiao Guangrong return true; 217126234f36SXiao Guangrong } 217226234f36SXiao Guangrong 217326234f36SXiao Guangrong static struct page 217426234f36SXiao Guangrong *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, 217526234f36SXiao Guangrong struct vm_area_struct *vma, unsigned long address, 217626234f36SXiao Guangrong int node) 217726234f36SXiao Guangrong { 217826234f36SXiao Guangrong VM_BUG_ON(*hpage); 217926234f36SXiao Guangrong /* 218026234f36SXiao Guangrong * Allocate the page while the vma is still valid and under 218126234f36SXiao Guangrong * the mmap_sem read mode so there is no memory allocation 218226234f36SXiao Guangrong * later when we take the mmap_sem in write mode. This is more 218326234f36SXiao Guangrong * friendly behavior (OTOH it may actually hide bugs) to 218426234f36SXiao Guangrong * filesystems in userland with daemons allocating memory in 218526234f36SXiao Guangrong * the userland I/O paths. Allocating memory with the 218626234f36SXiao Guangrong * mmap_sem in read mode is good idea also to allow greater 218726234f36SXiao Guangrong * scalability. 218826234f36SXiao Guangrong */ 218926234f36SXiao Guangrong *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address, 219026234f36SXiao Guangrong node, __GFP_OTHER_NODE); 219126234f36SXiao Guangrong 219226234f36SXiao Guangrong /* 219326234f36SXiao Guangrong * After allocating the hugepage, release the mmap_sem read lock in 219426234f36SXiao Guangrong * preparation for taking it in write mode. 219526234f36SXiao Guangrong */ 219626234f36SXiao Guangrong up_read(&mm->mmap_sem); 219726234f36SXiao Guangrong if (unlikely(!*hpage)) { 219826234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 219926234f36SXiao Guangrong *hpage = ERR_PTR(-ENOMEM); 220026234f36SXiao Guangrong return NULL; 220126234f36SXiao Guangrong } 220226234f36SXiao Guangrong 220326234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 220426234f36SXiao Guangrong return *hpage; 220526234f36SXiao Guangrong } 220626234f36SXiao Guangrong #else 220726234f36SXiao Guangrong static struct page *khugepaged_alloc_hugepage(bool *wait) 220826234f36SXiao Guangrong { 220926234f36SXiao Guangrong struct page *hpage; 221026234f36SXiao Guangrong 221126234f36SXiao Guangrong do { 221226234f36SXiao Guangrong hpage = alloc_hugepage(khugepaged_defrag()); 221326234f36SXiao Guangrong if (!hpage) { 221426234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 221526234f36SXiao Guangrong if (!*wait) 221626234f36SXiao Guangrong return NULL; 221726234f36SXiao Guangrong 221826234f36SXiao Guangrong *wait = false; 221926234f36SXiao Guangrong khugepaged_alloc_sleep(); 222026234f36SXiao Guangrong } else 222126234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 222226234f36SXiao Guangrong } while (unlikely(!hpage) && likely(khugepaged_enabled())); 222326234f36SXiao Guangrong 222426234f36SXiao Guangrong return hpage; 222526234f36SXiao Guangrong } 222626234f36SXiao Guangrong 222726234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 222826234f36SXiao Guangrong { 222926234f36SXiao Guangrong if (!*hpage) 223026234f36SXiao Guangrong *hpage = khugepaged_alloc_hugepage(wait); 223126234f36SXiao Guangrong 223226234f36SXiao Guangrong if (unlikely(!*hpage)) 223326234f36SXiao Guangrong return false; 223426234f36SXiao Guangrong 223526234f36SXiao Guangrong return true; 223626234f36SXiao Guangrong } 223726234f36SXiao Guangrong 223826234f36SXiao Guangrong static struct page 223926234f36SXiao Guangrong *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, 224026234f36SXiao Guangrong struct vm_area_struct *vma, unsigned long address, 224126234f36SXiao Guangrong int node) 224226234f36SXiao Guangrong { 224326234f36SXiao Guangrong up_read(&mm->mmap_sem); 224426234f36SXiao Guangrong VM_BUG_ON(!*hpage); 224526234f36SXiao Guangrong return *hpage; 224626234f36SXiao Guangrong } 224726234f36SXiao Guangrong #endif 224826234f36SXiao Guangrong 2249fa475e51SBob Liu static bool hugepage_vma_check(struct vm_area_struct *vma) 2250fa475e51SBob Liu { 2251fa475e51SBob Liu if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || 2252fa475e51SBob Liu (vma->vm_flags & VM_NOHUGEPAGE)) 2253fa475e51SBob Liu return false; 2254fa475e51SBob Liu 2255fa475e51SBob Liu if (!vma->anon_vma || vma->vm_ops) 2256fa475e51SBob Liu return false; 2257fa475e51SBob Liu if (is_vma_temporary_stack(vma)) 2258fa475e51SBob Liu return false; 2259fa475e51SBob Liu VM_BUG_ON(vma->vm_flags & VM_NO_THP); 2260fa475e51SBob Liu return true; 2261fa475e51SBob Liu } 2262fa475e51SBob Liu 2263ba76149fSAndrea Arcangeli static void collapse_huge_page(struct mm_struct *mm, 2264ba76149fSAndrea Arcangeli unsigned long address, 2265ce83d217SAndrea Arcangeli struct page **hpage, 22665c4b4be3SAndi Kleen struct vm_area_struct *vma, 22675c4b4be3SAndi Kleen int node) 2268ba76149fSAndrea Arcangeli { 2269ba76149fSAndrea Arcangeli pmd_t *pmd, _pmd; 2270ba76149fSAndrea Arcangeli pte_t *pte; 2271ba76149fSAndrea Arcangeli pgtable_t pgtable; 2272ba76149fSAndrea Arcangeli struct page *new_page; 2273ba76149fSAndrea Arcangeli spinlock_t *ptl; 2274ba76149fSAndrea Arcangeli int isolated; 2275ba76149fSAndrea Arcangeli unsigned long hstart, hend; 22762ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 22772ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 2278ba76149fSAndrea Arcangeli 2279ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 2280692e0b35SAndrea Arcangeli 228126234f36SXiao Guangrong /* release the mmap_sem read lock. */ 228226234f36SXiao Guangrong new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); 228326234f36SXiao Guangrong if (!new_page) 2284ce83d217SAndrea Arcangeli return; 2285ce83d217SAndrea Arcangeli 2286420256efSXiao Guangrong if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) 2287692e0b35SAndrea Arcangeli return; 2288ba76149fSAndrea Arcangeli 2289ba76149fSAndrea Arcangeli /* 2290ba76149fSAndrea Arcangeli * Prevent all access to pagetables with the exception of 2291ba76149fSAndrea Arcangeli * gup_fast later hanlded by the ptep_clear_flush and the VM 2292ba76149fSAndrea Arcangeli * handled by the anon_vma lock + PG_lock. 2293ba76149fSAndrea Arcangeli */ 2294ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 2295ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2296ba76149fSAndrea Arcangeli goto out; 2297ba76149fSAndrea Arcangeli 2298ba76149fSAndrea Arcangeli vma = find_vma(mm, address); 2299a8f531ebSLibin if (!vma) 2300a8f531ebSLibin goto out; 2301ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2302ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2303ba76149fSAndrea Arcangeli if (address < hstart || address + HPAGE_PMD_SIZE > hend) 2304ba76149fSAndrea Arcangeli goto out; 2305fa475e51SBob Liu if (!hugepage_vma_check(vma)) 2306ba76149fSAndrea Arcangeli goto out; 23076219049aSBob Liu pmd = mm_find_pmd(mm, address); 23086219049aSBob Liu if (!pmd) 2309ba76149fSAndrea Arcangeli goto out; 23106219049aSBob Liu if (pmd_trans_huge(*pmd)) 2311ba76149fSAndrea Arcangeli goto out; 2312ba76149fSAndrea Arcangeli 23134fc3f1d6SIngo Molnar anon_vma_lock_write(vma->anon_vma); 2314ba76149fSAndrea Arcangeli 2315ba76149fSAndrea Arcangeli pte = pte_offset_map(pmd, address); 2316ba76149fSAndrea Arcangeli ptl = pte_lockptr(mm, pmd); 2317ba76149fSAndrea Arcangeli 23182ec74c3eSSagi Grimberg mmun_start = address; 23192ec74c3eSSagi Grimberg mmun_end = address + HPAGE_PMD_SIZE; 23202ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2321ba76149fSAndrea Arcangeli spin_lock(&mm->page_table_lock); /* probably unnecessary */ 2322ba76149fSAndrea Arcangeli /* 2323ba76149fSAndrea Arcangeli * After this gup_fast can't run anymore. This also removes 2324ba76149fSAndrea Arcangeli * any huge TLB entry from the CPU so we won't allow 2325ba76149fSAndrea Arcangeli * huge and small TLB entries for the same virtual address 2326ba76149fSAndrea Arcangeli * to avoid the risk of CPU bugs in that area. 2327ba76149fSAndrea Arcangeli */ 23282ec74c3eSSagi Grimberg _pmd = pmdp_clear_flush(vma, address, pmd); 2329ba76149fSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 23302ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2331ba76149fSAndrea Arcangeli 2332ba76149fSAndrea Arcangeli spin_lock(ptl); 2333ba76149fSAndrea Arcangeli isolated = __collapse_huge_page_isolate(vma, address, pte); 2334ba76149fSAndrea Arcangeli spin_unlock(ptl); 2335ba76149fSAndrea Arcangeli 2336ba76149fSAndrea Arcangeli if (unlikely(!isolated)) { 2337453c7192SJohannes Weiner pte_unmap(pte); 2338ba76149fSAndrea Arcangeli spin_lock(&mm->page_table_lock); 2339ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 23407c342512SAneesh Kumar K.V /* 23417c342512SAneesh Kumar K.V * We can only use set_pmd_at when establishing 23427c342512SAneesh Kumar K.V * hugepmds and never for establishing regular pmds that 23437c342512SAneesh Kumar K.V * points to regular pagetables. Use pmd_populate for that 23447c342512SAneesh Kumar K.V */ 23457c342512SAneesh Kumar K.V pmd_populate(mm, pmd, pmd_pgtable(_pmd)); 2346ba76149fSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 234708b52706SKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2348ce83d217SAndrea Arcangeli goto out; 2349ba76149fSAndrea Arcangeli } 2350ba76149fSAndrea Arcangeli 2351ba76149fSAndrea Arcangeli /* 2352ba76149fSAndrea Arcangeli * All pages are isolated and locked so anon_vma rmap 2353ba76149fSAndrea Arcangeli * can't run anymore. 2354ba76149fSAndrea Arcangeli */ 235508b52706SKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2356ba76149fSAndrea Arcangeli 2357ba76149fSAndrea Arcangeli __collapse_huge_page_copy(pte, new_page, vma, address, ptl); 2358453c7192SJohannes Weiner pte_unmap(pte); 2359ba76149fSAndrea Arcangeli __SetPageUptodate(new_page); 2360ba76149fSAndrea Arcangeli pgtable = pmd_pgtable(_pmd); 2361ba76149fSAndrea Arcangeli 2362*3122359aSKirill A. Shutemov _pmd = mk_huge_pmd(new_page, vma->vm_page_prot); 2363*3122359aSKirill A. Shutemov _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); 2364ba76149fSAndrea Arcangeli 2365ba76149fSAndrea Arcangeli /* 2366ba76149fSAndrea Arcangeli * spin_lock() below is not the equivalent of smp_wmb(), so 2367ba76149fSAndrea Arcangeli * this is needed to avoid the copy_huge_page writes to become 2368ba76149fSAndrea Arcangeli * visible after the set_pmd_at() write. 2369ba76149fSAndrea Arcangeli */ 2370ba76149fSAndrea Arcangeli smp_wmb(); 2371ba76149fSAndrea Arcangeli 2372ba76149fSAndrea Arcangeli spin_lock(&mm->page_table_lock); 2373ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 2374ba76149fSAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, address); 2375fce144b4SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 2376ba76149fSAndrea Arcangeli set_pmd_at(mm, address, pmd, _pmd); 2377b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 2378ba76149fSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 2379ba76149fSAndrea Arcangeli 2380ba76149fSAndrea Arcangeli *hpage = NULL; 2381420256efSXiao Guangrong 2382ba76149fSAndrea Arcangeli khugepaged_pages_collapsed++; 2383ce83d217SAndrea Arcangeli out_up_write: 2384ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 23850bbbc0b3SAndrea Arcangeli return; 23860bbbc0b3SAndrea Arcangeli 2387ce83d217SAndrea Arcangeli out: 2388678ff896SKAMEZAWA Hiroyuki mem_cgroup_uncharge_page(new_page); 2389ce83d217SAndrea Arcangeli goto out_up_write; 2390ba76149fSAndrea Arcangeli } 2391ba76149fSAndrea Arcangeli 2392ba76149fSAndrea Arcangeli static int khugepaged_scan_pmd(struct mm_struct *mm, 2393ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 2394ba76149fSAndrea Arcangeli unsigned long address, 2395ba76149fSAndrea Arcangeli struct page **hpage) 2396ba76149fSAndrea Arcangeli { 2397ba76149fSAndrea Arcangeli pmd_t *pmd; 2398ba76149fSAndrea Arcangeli pte_t *pte, *_pte; 2399ba76149fSAndrea Arcangeli int ret = 0, referenced = 0, none = 0; 2400ba76149fSAndrea Arcangeli struct page *page; 2401ba76149fSAndrea Arcangeli unsigned long _address; 2402ba76149fSAndrea Arcangeli spinlock_t *ptl; 240300ef2d2fSDavid Rientjes int node = NUMA_NO_NODE; 2404ba76149fSAndrea Arcangeli 2405ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 2406ba76149fSAndrea Arcangeli 24076219049aSBob Liu pmd = mm_find_pmd(mm, address); 24086219049aSBob Liu if (!pmd) 2409ba76149fSAndrea Arcangeli goto out; 24106219049aSBob Liu if (pmd_trans_huge(*pmd)) 2411ba76149fSAndrea Arcangeli goto out; 2412ba76149fSAndrea Arcangeli 2413ba76149fSAndrea Arcangeli pte = pte_offset_map_lock(mm, pmd, address, &ptl); 2414ba76149fSAndrea Arcangeli for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; 2415ba76149fSAndrea Arcangeli _pte++, _address += PAGE_SIZE) { 2416ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2417ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 2418ba76149fSAndrea Arcangeli if (++none <= khugepaged_max_ptes_none) 2419ba76149fSAndrea Arcangeli continue; 2420ba76149fSAndrea Arcangeli else 2421ba76149fSAndrea Arcangeli goto out_unmap; 2422ba76149fSAndrea Arcangeli } 2423ba76149fSAndrea Arcangeli if (!pte_present(pteval) || !pte_write(pteval)) 2424ba76149fSAndrea Arcangeli goto out_unmap; 2425ba76149fSAndrea Arcangeli page = vm_normal_page(vma, _address, pteval); 2426ba76149fSAndrea Arcangeli if (unlikely(!page)) 2427ba76149fSAndrea Arcangeli goto out_unmap; 24285c4b4be3SAndi Kleen /* 24295c4b4be3SAndi Kleen * Chose the node of the first page. This could 24305c4b4be3SAndi Kleen * be more sophisticated and look at more pages, 24315c4b4be3SAndi Kleen * but isn't for now. 24325c4b4be3SAndi Kleen */ 243300ef2d2fSDavid Rientjes if (node == NUMA_NO_NODE) 24345c4b4be3SAndi Kleen node = page_to_nid(page); 2435ba76149fSAndrea Arcangeli VM_BUG_ON(PageCompound(page)); 2436ba76149fSAndrea Arcangeli if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) 2437ba76149fSAndrea Arcangeli goto out_unmap; 2438ba76149fSAndrea Arcangeli /* cannot use mapcount: can't collapse if there's a gup pin */ 2439ba76149fSAndrea Arcangeli if (page_count(page) != 1) 2440ba76149fSAndrea Arcangeli goto out_unmap; 24418ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 24428ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 2443ba76149fSAndrea Arcangeli referenced = 1; 2444ba76149fSAndrea Arcangeli } 2445ba76149fSAndrea Arcangeli if (referenced) 2446ba76149fSAndrea Arcangeli ret = 1; 2447ba76149fSAndrea Arcangeli out_unmap: 2448ba76149fSAndrea Arcangeli pte_unmap_unlock(pte, ptl); 2449ce83d217SAndrea Arcangeli if (ret) 2450ce83d217SAndrea Arcangeli /* collapse_huge_page will return with the mmap_sem released */ 24515c4b4be3SAndi Kleen collapse_huge_page(mm, address, hpage, vma, node); 2452ba76149fSAndrea Arcangeli out: 2453ba76149fSAndrea Arcangeli return ret; 2454ba76149fSAndrea Arcangeli } 2455ba76149fSAndrea Arcangeli 2456ba76149fSAndrea Arcangeli static void collect_mm_slot(struct mm_slot *mm_slot) 2457ba76149fSAndrea Arcangeli { 2458ba76149fSAndrea Arcangeli struct mm_struct *mm = mm_slot->mm; 2459ba76149fSAndrea Arcangeli 2460b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2461ba76149fSAndrea Arcangeli 2462ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm)) { 2463ba76149fSAndrea Arcangeli /* free mm_slot */ 246443b5fbbdSSasha Levin hash_del(&mm_slot->hash); 2465ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 2466ba76149fSAndrea Arcangeli 2467ba76149fSAndrea Arcangeli /* 2468ba76149fSAndrea Arcangeli * Not strictly needed because the mm exited already. 2469ba76149fSAndrea Arcangeli * 2470ba76149fSAndrea Arcangeli * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 2471ba76149fSAndrea Arcangeli */ 2472ba76149fSAndrea Arcangeli 2473ba76149fSAndrea Arcangeli /* khugepaged_mm_lock actually not necessary for the below */ 2474ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2475ba76149fSAndrea Arcangeli mmdrop(mm); 2476ba76149fSAndrea Arcangeli } 2477ba76149fSAndrea Arcangeli } 2478ba76149fSAndrea Arcangeli 2479ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_mm_slot(unsigned int pages, 2480ba76149fSAndrea Arcangeli struct page **hpage) 24812f1da642SH Hartley Sweeten __releases(&khugepaged_mm_lock) 24822f1da642SH Hartley Sweeten __acquires(&khugepaged_mm_lock) 2483ba76149fSAndrea Arcangeli { 2484ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2485ba76149fSAndrea Arcangeli struct mm_struct *mm; 2486ba76149fSAndrea Arcangeli struct vm_area_struct *vma; 2487ba76149fSAndrea Arcangeli int progress = 0; 2488ba76149fSAndrea Arcangeli 2489ba76149fSAndrea Arcangeli VM_BUG_ON(!pages); 2490b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2491ba76149fSAndrea Arcangeli 2492ba76149fSAndrea Arcangeli if (khugepaged_scan.mm_slot) 2493ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2494ba76149fSAndrea Arcangeli else { 2495ba76149fSAndrea Arcangeli mm_slot = list_entry(khugepaged_scan.mm_head.next, 2496ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2497ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2498ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = mm_slot; 2499ba76149fSAndrea Arcangeli } 2500ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2501ba76149fSAndrea Arcangeli 2502ba76149fSAndrea Arcangeli mm = mm_slot->mm; 2503ba76149fSAndrea Arcangeli down_read(&mm->mmap_sem); 2504ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2505ba76149fSAndrea Arcangeli vma = NULL; 2506ba76149fSAndrea Arcangeli else 2507ba76149fSAndrea Arcangeli vma = find_vma(mm, khugepaged_scan.address); 2508ba76149fSAndrea Arcangeli 2509ba76149fSAndrea Arcangeli progress++; 2510ba76149fSAndrea Arcangeli for (; vma; vma = vma->vm_next) { 2511ba76149fSAndrea Arcangeli unsigned long hstart, hend; 2512ba76149fSAndrea Arcangeli 2513ba76149fSAndrea Arcangeli cond_resched(); 2514ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) { 2515ba76149fSAndrea Arcangeli progress++; 2516ba76149fSAndrea Arcangeli break; 2517ba76149fSAndrea Arcangeli } 2518fa475e51SBob Liu if (!hugepage_vma_check(vma)) { 2519a7d6e4ecSAndrea Arcangeli skip: 2520ba76149fSAndrea Arcangeli progress++; 2521ba76149fSAndrea Arcangeli continue; 2522ba76149fSAndrea Arcangeli } 2523ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2524ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2525a7d6e4ecSAndrea Arcangeli if (hstart >= hend) 2526a7d6e4ecSAndrea Arcangeli goto skip; 2527a7d6e4ecSAndrea Arcangeli if (khugepaged_scan.address > hend) 2528a7d6e4ecSAndrea Arcangeli goto skip; 2529ba76149fSAndrea Arcangeli if (khugepaged_scan.address < hstart) 2530ba76149fSAndrea Arcangeli khugepaged_scan.address = hstart; 2531a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); 2532ba76149fSAndrea Arcangeli 2533ba76149fSAndrea Arcangeli while (khugepaged_scan.address < hend) { 2534ba76149fSAndrea Arcangeli int ret; 2535ba76149fSAndrea Arcangeli cond_resched(); 2536ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2537ba76149fSAndrea Arcangeli goto breakouterloop; 2538ba76149fSAndrea Arcangeli 2539ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address < hstart || 2540ba76149fSAndrea Arcangeli khugepaged_scan.address + HPAGE_PMD_SIZE > 2541ba76149fSAndrea Arcangeli hend); 2542ba76149fSAndrea Arcangeli ret = khugepaged_scan_pmd(mm, vma, 2543ba76149fSAndrea Arcangeli khugepaged_scan.address, 2544ba76149fSAndrea Arcangeli hpage); 2545ba76149fSAndrea Arcangeli /* move to next address */ 2546ba76149fSAndrea Arcangeli khugepaged_scan.address += HPAGE_PMD_SIZE; 2547ba76149fSAndrea Arcangeli progress += HPAGE_PMD_NR; 2548ba76149fSAndrea Arcangeli if (ret) 2549ba76149fSAndrea Arcangeli /* we released mmap_sem so break loop */ 2550ba76149fSAndrea Arcangeli goto breakouterloop_mmap_sem; 2551ba76149fSAndrea Arcangeli if (progress >= pages) 2552ba76149fSAndrea Arcangeli goto breakouterloop; 2553ba76149fSAndrea Arcangeli } 2554ba76149fSAndrea Arcangeli } 2555ba76149fSAndrea Arcangeli breakouterloop: 2556ba76149fSAndrea Arcangeli up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ 2557ba76149fSAndrea Arcangeli breakouterloop_mmap_sem: 2558ba76149fSAndrea Arcangeli 2559ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2560a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); 2561ba76149fSAndrea Arcangeli /* 2562ba76149fSAndrea Arcangeli * Release the current mm_slot if this mm is about to die, or 2563ba76149fSAndrea Arcangeli * if we scanned all vmas of this mm. 2564ba76149fSAndrea Arcangeli */ 2565ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm) || !vma) { 2566ba76149fSAndrea Arcangeli /* 2567ba76149fSAndrea Arcangeli * Make sure that if mm_users is reaching zero while 2568ba76149fSAndrea Arcangeli * khugepaged runs here, khugepaged_exit will find 2569ba76149fSAndrea Arcangeli * mm_slot not pointing to the exiting mm. 2570ba76149fSAndrea Arcangeli */ 2571ba76149fSAndrea Arcangeli if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { 2572ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = list_entry( 2573ba76149fSAndrea Arcangeli mm_slot->mm_node.next, 2574ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2575ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2576ba76149fSAndrea Arcangeli } else { 2577ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2578ba76149fSAndrea Arcangeli khugepaged_full_scans++; 2579ba76149fSAndrea Arcangeli } 2580ba76149fSAndrea Arcangeli 2581ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2582ba76149fSAndrea Arcangeli } 2583ba76149fSAndrea Arcangeli 2584ba76149fSAndrea Arcangeli return progress; 2585ba76149fSAndrea Arcangeli } 2586ba76149fSAndrea Arcangeli 2587ba76149fSAndrea Arcangeli static int khugepaged_has_work(void) 2588ba76149fSAndrea Arcangeli { 2589ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) && 2590ba76149fSAndrea Arcangeli khugepaged_enabled(); 2591ba76149fSAndrea Arcangeli } 2592ba76149fSAndrea Arcangeli 2593ba76149fSAndrea Arcangeli static int khugepaged_wait_event(void) 2594ba76149fSAndrea Arcangeli { 2595ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) || 25962017c0bfSXiao Guangrong kthread_should_stop(); 2597ba76149fSAndrea Arcangeli } 2598ba76149fSAndrea Arcangeli 2599d516904bSXiao Guangrong static void khugepaged_do_scan(void) 2600d516904bSXiao Guangrong { 2601d516904bSXiao Guangrong struct page *hpage = NULL; 2602ba76149fSAndrea Arcangeli unsigned int progress = 0, pass_through_head = 0; 2603ba76149fSAndrea Arcangeli unsigned int pages = khugepaged_pages_to_scan; 2604d516904bSXiao Guangrong bool wait = true; 2605ba76149fSAndrea Arcangeli 2606ba76149fSAndrea Arcangeli barrier(); /* write khugepaged_pages_to_scan to local stack */ 2607ba76149fSAndrea Arcangeli 2608ba76149fSAndrea Arcangeli while (progress < pages) { 260926234f36SXiao Guangrong if (!khugepaged_prealloc_page(&hpage, &wait)) 261026234f36SXiao Guangrong break; 2611d516904bSXiao Guangrong 2612420256efSXiao Guangrong cond_resched(); 2613ba76149fSAndrea Arcangeli 2614878aee7dSAndrea Arcangeli if (unlikely(kthread_should_stop() || freezing(current))) 2615878aee7dSAndrea Arcangeli break; 2616878aee7dSAndrea Arcangeli 2617ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2618ba76149fSAndrea Arcangeli if (!khugepaged_scan.mm_slot) 2619ba76149fSAndrea Arcangeli pass_through_head++; 2620ba76149fSAndrea Arcangeli if (khugepaged_has_work() && 2621ba76149fSAndrea Arcangeli pass_through_head < 2) 2622ba76149fSAndrea Arcangeli progress += khugepaged_scan_mm_slot(pages - progress, 2623d516904bSXiao Guangrong &hpage); 2624ba76149fSAndrea Arcangeli else 2625ba76149fSAndrea Arcangeli progress = pages; 2626ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2627ba76149fSAndrea Arcangeli } 2628ba76149fSAndrea Arcangeli 2629d516904bSXiao Guangrong if (!IS_ERR_OR_NULL(hpage)) 2630d516904bSXiao Guangrong put_page(hpage); 2631ba76149fSAndrea Arcangeli } 26320bbbc0b3SAndrea Arcangeli 26332017c0bfSXiao Guangrong static void khugepaged_wait_work(void) 26342017c0bfSXiao Guangrong { 26352017c0bfSXiao Guangrong try_to_freeze(); 26362017c0bfSXiao Guangrong 26372017c0bfSXiao Guangrong if (khugepaged_has_work()) { 26382017c0bfSXiao Guangrong if (!khugepaged_scan_sleep_millisecs) 26392017c0bfSXiao Guangrong return; 26402017c0bfSXiao Guangrong 26412017c0bfSXiao Guangrong wait_event_freezable_timeout(khugepaged_wait, 26422017c0bfSXiao Guangrong kthread_should_stop(), 26432017c0bfSXiao Guangrong msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); 26442017c0bfSXiao Guangrong return; 26452017c0bfSXiao Guangrong } 26462017c0bfSXiao Guangrong 26472017c0bfSXiao Guangrong if (khugepaged_enabled()) 26482017c0bfSXiao Guangrong wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); 26492017c0bfSXiao Guangrong } 26502017c0bfSXiao Guangrong 2651ba76149fSAndrea Arcangeli static int khugepaged(void *none) 2652ba76149fSAndrea Arcangeli { 2653ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2654ba76149fSAndrea Arcangeli 2655878aee7dSAndrea Arcangeli set_freezable(); 2656ba76149fSAndrea Arcangeli set_user_nice(current, 19); 2657ba76149fSAndrea Arcangeli 2658b7231789SXiao Guangrong while (!kthread_should_stop()) { 2659b7231789SXiao Guangrong khugepaged_do_scan(); 2660b7231789SXiao Guangrong khugepaged_wait_work(); 2661b7231789SXiao Guangrong } 2662ba76149fSAndrea Arcangeli 2663ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2664ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2665ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2666ba76149fSAndrea Arcangeli if (mm_slot) 2667ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2668ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2669ba76149fSAndrea Arcangeli return 0; 2670ba76149fSAndrea Arcangeli } 2671ba76149fSAndrea Arcangeli 2672c5a647d0SKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2673c5a647d0SKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2674c5a647d0SKirill A. Shutemov { 2675c5a647d0SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2676c5a647d0SKirill A. Shutemov pgtable_t pgtable; 2677c5a647d0SKirill A. Shutemov pmd_t _pmd; 2678c5a647d0SKirill A. Shutemov int i; 2679c5a647d0SKirill A. Shutemov 2680c5a647d0SKirill A. Shutemov pmdp_clear_flush(vma, haddr, pmd); 2681c5a647d0SKirill A. Shutemov /* leave pmd empty until pte is filled */ 2682c5a647d0SKirill A. Shutemov 26836b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2684c5a647d0SKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2685c5a647d0SKirill A. Shutemov 2686c5a647d0SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 2687c5a647d0SKirill A. Shutemov pte_t *pte, entry; 2688c5a647d0SKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 2689c5a647d0SKirill A. Shutemov entry = pte_mkspecial(entry); 2690c5a647d0SKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 2691c5a647d0SKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 2692c5a647d0SKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 2693c5a647d0SKirill A. Shutemov pte_unmap(pte); 2694c5a647d0SKirill A. Shutemov } 2695c5a647d0SKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2696c5a647d0SKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 269797ae1749SKirill A. Shutemov put_huge_zero_page(); 2698c5a647d0SKirill A. Shutemov } 2699c5a647d0SKirill A. Shutemov 2700e180377fSKirill A. Shutemov void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, 2701e180377fSKirill A. Shutemov pmd_t *pmd) 270271e3aac0SAndrea Arcangeli { 270371e3aac0SAndrea Arcangeli struct page *page; 2704e180377fSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2705c5a647d0SKirill A. Shutemov unsigned long haddr = address & HPAGE_PMD_MASK; 2706c5a647d0SKirill A. Shutemov unsigned long mmun_start; /* For mmu_notifiers */ 2707c5a647d0SKirill A. Shutemov unsigned long mmun_end; /* For mmu_notifiers */ 2708e180377fSKirill A. Shutemov 2709e180377fSKirill A. Shutemov BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); 271071e3aac0SAndrea Arcangeli 2711c5a647d0SKirill A. Shutemov mmun_start = haddr; 2712c5a647d0SKirill A. Shutemov mmun_end = haddr + HPAGE_PMD_SIZE; 2713c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 271471e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 271571e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(*pmd))) { 271671e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 2717c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2718c5a647d0SKirill A. Shutemov return; 2719c5a647d0SKirill A. Shutemov } 2720c5a647d0SKirill A. Shutemov if (is_huge_zero_pmd(*pmd)) { 2721c5a647d0SKirill A. Shutemov __split_huge_zero_page_pmd(vma, haddr, pmd); 2722c5a647d0SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 2723c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 272471e3aac0SAndrea Arcangeli return; 272571e3aac0SAndrea Arcangeli } 272671e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 272771e3aac0SAndrea Arcangeli VM_BUG_ON(!page_count(page)); 272871e3aac0SAndrea Arcangeli get_page(page); 272971e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 2730c5a647d0SKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 273171e3aac0SAndrea Arcangeli 273271e3aac0SAndrea Arcangeli split_huge_page(page); 273371e3aac0SAndrea Arcangeli 273471e3aac0SAndrea Arcangeli put_page(page); 273571e3aac0SAndrea Arcangeli BUG_ON(pmd_trans_huge(*pmd)); 273671e3aac0SAndrea Arcangeli } 273794fcc585SAndrea Arcangeli 2738e180377fSKirill A. Shutemov void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, 2739e180377fSKirill A. Shutemov pmd_t *pmd) 2740e180377fSKirill A. Shutemov { 2741e180377fSKirill A. Shutemov struct vm_area_struct *vma; 2742e180377fSKirill A. Shutemov 2743e180377fSKirill A. Shutemov vma = find_vma(mm, address); 2744e180377fSKirill A. Shutemov BUG_ON(vma == NULL); 2745e180377fSKirill A. Shutemov split_huge_page_pmd(vma, address, pmd); 2746e180377fSKirill A. Shutemov } 2747e180377fSKirill A. Shutemov 274894fcc585SAndrea Arcangeli static void split_huge_page_address(struct mm_struct *mm, 274994fcc585SAndrea Arcangeli unsigned long address) 275094fcc585SAndrea Arcangeli { 275194fcc585SAndrea Arcangeli pmd_t *pmd; 275294fcc585SAndrea Arcangeli 275394fcc585SAndrea Arcangeli VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); 275494fcc585SAndrea Arcangeli 27556219049aSBob Liu pmd = mm_find_pmd(mm, address); 27566219049aSBob Liu if (!pmd) 275794fcc585SAndrea Arcangeli return; 275894fcc585SAndrea Arcangeli /* 275994fcc585SAndrea Arcangeli * Caller holds the mmap_sem write mode, so a huge pmd cannot 276094fcc585SAndrea Arcangeli * materialize from under us. 276194fcc585SAndrea Arcangeli */ 2762e180377fSKirill A. Shutemov split_huge_page_pmd_mm(mm, address, pmd); 276394fcc585SAndrea Arcangeli } 276494fcc585SAndrea Arcangeli 276594fcc585SAndrea Arcangeli void __vma_adjust_trans_huge(struct vm_area_struct *vma, 276694fcc585SAndrea Arcangeli unsigned long start, 276794fcc585SAndrea Arcangeli unsigned long end, 276894fcc585SAndrea Arcangeli long adjust_next) 276994fcc585SAndrea Arcangeli { 277094fcc585SAndrea Arcangeli /* 277194fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 277294fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 277394fcc585SAndrea Arcangeli * an huge pmd. 277494fcc585SAndrea Arcangeli */ 277594fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 277694fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 277794fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 277894fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, start); 277994fcc585SAndrea Arcangeli 278094fcc585SAndrea Arcangeli /* 278194fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 278294fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 278394fcc585SAndrea Arcangeli * an huge pmd. 278494fcc585SAndrea Arcangeli */ 278594fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 278694fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 278794fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 278894fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, end); 278994fcc585SAndrea Arcangeli 279094fcc585SAndrea Arcangeli /* 279194fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 279294fcc585SAndrea Arcangeli * vm_next->vm_start isn't page aligned and it could previously 279394fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 279494fcc585SAndrea Arcangeli */ 279594fcc585SAndrea Arcangeli if (adjust_next > 0) { 279694fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 279794fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 279894fcc585SAndrea Arcangeli nstart += adjust_next << PAGE_SHIFT; 279994fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 280094fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 280194fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 280294fcc585SAndrea Arcangeli split_huge_page_address(next->vm_mm, nstart); 280394fcc585SAndrea Arcangeli } 280494fcc585SAndrea Arcangeli } 2805