171e3aac0SAndrea Arcangeli /* 271e3aac0SAndrea Arcangeli * Copyright (C) 2009 Red Hat, Inc. 371e3aac0SAndrea Arcangeli * 471e3aac0SAndrea Arcangeli * This work is licensed under the terms of the GNU GPL, version 2. See 571e3aac0SAndrea Arcangeli * the COPYING file in the top-level directory. 671e3aac0SAndrea Arcangeli */ 771e3aac0SAndrea Arcangeli 8ae3a8c1cSAndrew Morton #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9ae3a8c1cSAndrew Morton 1071e3aac0SAndrea Arcangeli #include <linux/mm.h> 1171e3aac0SAndrea Arcangeli #include <linux/sched.h> 1271e3aac0SAndrea Arcangeli #include <linux/highmem.h> 1371e3aac0SAndrea Arcangeli #include <linux/hugetlb.h> 1471e3aac0SAndrea Arcangeli #include <linux/mmu_notifier.h> 1571e3aac0SAndrea Arcangeli #include <linux/rmap.h> 1671e3aac0SAndrea Arcangeli #include <linux/swap.h> 1797ae1749SKirill A. Shutemov #include <linux/shrinker.h> 18ba76149fSAndrea Arcangeli #include <linux/mm_inline.h> 194897c765SMatthew Wilcox #include <linux/dax.h> 20ba76149fSAndrea Arcangeli #include <linux/kthread.h> 21ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 22878aee7dSAndrea Arcangeli #include <linux/freezer.h> 23a664b2d8SAndrea Arcangeli #include <linux/mman.h> 24325adeb5SRalf Baechle #include <linux/pagemap.h> 254daae3b4SMel Gorman #include <linux/migrate.h> 2643b5fbbdSSasha Levin #include <linux/hashtable.h> 276b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 2833c3fc71SVladimir Davydov #include <linux/page_idle.h> 2997ae1749SKirill A. Shutemov 3071e3aac0SAndrea Arcangeli #include <asm/tlb.h> 3171e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 3271e3aac0SAndrea Arcangeli #include "internal.h" 3371e3aac0SAndrea Arcangeli 347d2eba05SEbru Akagunduz enum scan_result { 357d2eba05SEbru Akagunduz SCAN_FAIL, 367d2eba05SEbru Akagunduz SCAN_SUCCEED, 377d2eba05SEbru Akagunduz SCAN_PMD_NULL, 387d2eba05SEbru Akagunduz SCAN_EXCEED_NONE_PTE, 397d2eba05SEbru Akagunduz SCAN_PTE_NON_PRESENT, 407d2eba05SEbru Akagunduz SCAN_PAGE_RO, 417d2eba05SEbru Akagunduz SCAN_NO_REFERENCED_PAGE, 427d2eba05SEbru Akagunduz SCAN_PAGE_NULL, 437d2eba05SEbru Akagunduz SCAN_SCAN_ABORT, 447d2eba05SEbru Akagunduz SCAN_PAGE_COUNT, 457d2eba05SEbru Akagunduz SCAN_PAGE_LRU, 467d2eba05SEbru Akagunduz SCAN_PAGE_LOCK, 477d2eba05SEbru Akagunduz SCAN_PAGE_ANON, 48b1caa957SKirill A. Shutemov SCAN_PAGE_COMPOUND, 497d2eba05SEbru Akagunduz SCAN_ANY_PROCESS, 507d2eba05SEbru Akagunduz SCAN_VMA_NULL, 517d2eba05SEbru Akagunduz SCAN_VMA_CHECK, 527d2eba05SEbru Akagunduz SCAN_ADDRESS_RANGE, 537d2eba05SEbru Akagunduz SCAN_SWAP_CACHE_PAGE, 547d2eba05SEbru Akagunduz SCAN_DEL_PAGE_LRU, 557d2eba05SEbru Akagunduz SCAN_ALLOC_HUGE_PAGE_FAIL, 567d2eba05SEbru Akagunduz SCAN_CGROUP_CHARGE_FAIL 577d2eba05SEbru Akagunduz }; 587d2eba05SEbru Akagunduz 597d2eba05SEbru Akagunduz #define CREATE_TRACE_POINTS 607d2eba05SEbru Akagunduz #include <trace/events/huge_memory.h> 617d2eba05SEbru Akagunduz 62ba76149fSAndrea Arcangeli /* 638bfa3f9aSJianguo Wu * By default transparent hugepage support is disabled in order that avoid 648bfa3f9aSJianguo Wu * to risk increase the memory footprint of applications without a guaranteed 658bfa3f9aSJianguo Wu * benefit. When transparent hugepage support is enabled, is for all mappings, 668bfa3f9aSJianguo Wu * and khugepaged scans all mappings. 678bfa3f9aSJianguo Wu * Defrag is invoked by khugepaged hugepage allocations and by page faults 688bfa3f9aSJianguo Wu * for all hugepage allocations. 69ba76149fSAndrea Arcangeli */ 7071e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 7113ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 72ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 7313ece886SAndrea Arcangeli #endif 7413ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 7513ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 7613ece886SAndrea Arcangeli #endif 77d39d33c3SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| 7879da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 7979da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 80ba76149fSAndrea Arcangeli 81ba76149fSAndrea Arcangeli /* default scan 8*512 pte (or vmas) every 30 second */ 82ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; 83ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_collapsed; 84ba76149fSAndrea Arcangeli static unsigned int khugepaged_full_scans; 85ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; 86ba76149fSAndrea Arcangeli /* during fragmentation poll the hugepage allocator once every minute */ 87ba76149fSAndrea Arcangeli static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; 88ba76149fSAndrea Arcangeli static struct task_struct *khugepaged_thread __read_mostly; 89ba76149fSAndrea Arcangeli static DEFINE_MUTEX(khugepaged_mutex); 90ba76149fSAndrea Arcangeli static DEFINE_SPINLOCK(khugepaged_mm_lock); 91ba76149fSAndrea Arcangeli static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); 92ba76149fSAndrea Arcangeli /* 93ba76149fSAndrea Arcangeli * default collapse hugepages if there is at least one pte mapped like 94ba76149fSAndrea Arcangeli * it would have happened if the vma was large enough during page 95ba76149fSAndrea Arcangeli * fault. 96ba76149fSAndrea Arcangeli */ 97ba76149fSAndrea Arcangeli static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; 98ba76149fSAndrea Arcangeli 99ba76149fSAndrea Arcangeli static int khugepaged(void *none); 100ba76149fSAndrea Arcangeli static int khugepaged_slab_init(void); 10165ebb64fSKirill A. Shutemov static void khugepaged_slab_exit(void); 102ba76149fSAndrea Arcangeli 10343b5fbbdSSasha Levin #define MM_SLOTS_HASH_BITS 10 10443b5fbbdSSasha Levin static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); 10543b5fbbdSSasha Levin 106ba76149fSAndrea Arcangeli static struct kmem_cache *mm_slot_cache __read_mostly; 107ba76149fSAndrea Arcangeli 108ba76149fSAndrea Arcangeli /** 109ba76149fSAndrea Arcangeli * struct mm_slot - hash lookup from mm to mm_slot 110ba76149fSAndrea Arcangeli * @hash: hash collision list 111ba76149fSAndrea Arcangeli * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head 112ba76149fSAndrea Arcangeli * @mm: the mm that this information is valid for 113ba76149fSAndrea Arcangeli */ 114ba76149fSAndrea Arcangeli struct mm_slot { 115ba76149fSAndrea Arcangeli struct hlist_node hash; 116ba76149fSAndrea Arcangeli struct list_head mm_node; 117ba76149fSAndrea Arcangeli struct mm_struct *mm; 118ba76149fSAndrea Arcangeli }; 119ba76149fSAndrea Arcangeli 120ba76149fSAndrea Arcangeli /** 121ba76149fSAndrea Arcangeli * struct khugepaged_scan - cursor for scanning 122ba76149fSAndrea Arcangeli * @mm_head: the head of the mm list to scan 123ba76149fSAndrea Arcangeli * @mm_slot: the current mm_slot we are scanning 124ba76149fSAndrea Arcangeli * @address: the next address inside that to be scanned 125ba76149fSAndrea Arcangeli * 126ba76149fSAndrea Arcangeli * There is only the one khugepaged_scan instance of this cursor structure. 127ba76149fSAndrea Arcangeli */ 128ba76149fSAndrea Arcangeli struct khugepaged_scan { 129ba76149fSAndrea Arcangeli struct list_head mm_head; 130ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 131ba76149fSAndrea Arcangeli unsigned long address; 1322f1da642SH Hartley Sweeten }; 1332f1da642SH Hartley Sweeten static struct khugepaged_scan khugepaged_scan = { 134ba76149fSAndrea Arcangeli .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), 135ba76149fSAndrea Arcangeli }; 136ba76149fSAndrea Arcangeli 137f000565aSAndrea Arcangeli 1382c0b80d4SNicholas Krause static void set_recommended_min_free_kbytes(void) 139f000565aSAndrea Arcangeli { 140f000565aSAndrea Arcangeli struct zone *zone; 141f000565aSAndrea Arcangeli int nr_zones = 0; 142f000565aSAndrea Arcangeli unsigned long recommended_min; 143f000565aSAndrea Arcangeli 144f000565aSAndrea Arcangeli for_each_populated_zone(zone) 145f000565aSAndrea Arcangeli nr_zones++; 146f000565aSAndrea Arcangeli 147974a786eSMel Gorman /* Ensure 2 pageblocks are free to assist fragmentation avoidance */ 148f000565aSAndrea Arcangeli recommended_min = pageblock_nr_pages * nr_zones * 2; 149f000565aSAndrea Arcangeli 150f000565aSAndrea Arcangeli /* 151f000565aSAndrea Arcangeli * Make sure that on average at least two pageblocks are almost free 152f000565aSAndrea Arcangeli * of another type, one for a migratetype to fall back to and a 153f000565aSAndrea Arcangeli * second to avoid subsequent fallbacks of other types There are 3 154f000565aSAndrea Arcangeli * MIGRATE_TYPES we care about. 155f000565aSAndrea Arcangeli */ 156f000565aSAndrea Arcangeli recommended_min += pageblock_nr_pages * nr_zones * 157f000565aSAndrea Arcangeli MIGRATE_PCPTYPES * MIGRATE_PCPTYPES; 158f000565aSAndrea Arcangeli 159f000565aSAndrea Arcangeli /* don't ever allow to reserve more than 5% of the lowmem */ 160f000565aSAndrea Arcangeli recommended_min = min(recommended_min, 161f000565aSAndrea Arcangeli (unsigned long) nr_free_buffer_pages() / 20); 162f000565aSAndrea Arcangeli recommended_min <<= (PAGE_SHIFT-10); 163f000565aSAndrea Arcangeli 16442aa83cbSHan Pingtian if (recommended_min > min_free_kbytes) { 16542aa83cbSHan Pingtian if (user_min_free_kbytes >= 0) 16642aa83cbSHan Pingtian pr_info("raising min_free_kbytes from %d to %lu " 16742aa83cbSHan Pingtian "to help transparent hugepage allocations\n", 16842aa83cbSHan Pingtian min_free_kbytes, recommended_min); 16942aa83cbSHan Pingtian 170f000565aSAndrea Arcangeli min_free_kbytes = recommended_min; 17142aa83cbSHan Pingtian } 172f000565aSAndrea Arcangeli setup_per_zone_wmarks(); 173f000565aSAndrea Arcangeli } 174f000565aSAndrea Arcangeli 17579553da2SKirill A. Shutemov static int start_stop_khugepaged(void) 176ba76149fSAndrea Arcangeli { 177ba76149fSAndrea Arcangeli int err = 0; 178ba76149fSAndrea Arcangeli if (khugepaged_enabled()) { 179ba76149fSAndrea Arcangeli if (!khugepaged_thread) 180ba76149fSAndrea Arcangeli khugepaged_thread = kthread_run(khugepaged, NULL, 181ba76149fSAndrea Arcangeli "khugepaged"); 18218e8e5c7SViresh Kumar if (IS_ERR(khugepaged_thread)) { 183ae3a8c1cSAndrew Morton pr_err("khugepaged: kthread_run(khugepaged) failed\n"); 184ba76149fSAndrea Arcangeli err = PTR_ERR(khugepaged_thread); 185ba76149fSAndrea Arcangeli khugepaged_thread = NULL; 18679553da2SKirill A. Shutemov goto fail; 187ba76149fSAndrea Arcangeli } 188911891afSXiao Guangrong 189911891afSXiao Guangrong if (!list_empty(&khugepaged_scan.mm_head)) 190ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 191f000565aSAndrea Arcangeli 192f000565aSAndrea Arcangeli set_recommended_min_free_kbytes(); 193911891afSXiao Guangrong } else if (khugepaged_thread) { 194911891afSXiao Guangrong kthread_stop(khugepaged_thread); 195911891afSXiao Guangrong khugepaged_thread = NULL; 196911891afSXiao Guangrong } 19779553da2SKirill A. Shutemov fail: 198ba76149fSAndrea Arcangeli return err; 199ba76149fSAndrea Arcangeli } 20071e3aac0SAndrea Arcangeli 20197ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 20256873f43SWang, Yalin struct page *huge_zero_page __read_mostly; 2034a6c1297SKirill A. Shutemov 204fc437044SMatthew Wilcox struct page *get_huge_zero_page(void) 20597ae1749SKirill A. Shutemov { 20697ae1749SKirill A. Shutemov struct page *zero_page; 20797ae1749SKirill A. Shutemov retry: 20897ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 2094db0c3c2SJason Low return READ_ONCE(huge_zero_page); 21097ae1749SKirill A. Shutemov 21197ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 21297ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 213d8a8e1f0SKirill A. Shutemov if (!zero_page) { 214d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 2155918d10aSKirill A. Shutemov return NULL; 216d8a8e1f0SKirill A. Shutemov } 217d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC); 21897ae1749SKirill A. Shutemov preempt_disable(); 2195918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 22097ae1749SKirill A. Shutemov preempt_enable(); 2215ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 22297ae1749SKirill A. Shutemov goto retry; 22397ae1749SKirill A. Shutemov } 22497ae1749SKirill A. Shutemov 22597ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 22697ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 22797ae1749SKirill A. Shutemov preempt_enable(); 2284db0c3c2SJason Low return READ_ONCE(huge_zero_page); 22997ae1749SKirill A. Shutemov } 23097ae1749SKirill A. Shutemov 23197ae1749SKirill A. Shutemov static void put_huge_zero_page(void) 23297ae1749SKirill A. Shutemov { 23397ae1749SKirill A. Shutemov /* 23497ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 23597ae1749SKirill A. Shutemov * last reference. 23697ae1749SKirill A. Shutemov */ 23797ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 23897ae1749SKirill A. Shutemov } 23997ae1749SKirill A. Shutemov 24048896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 24197ae1749SKirill A. Shutemov struct shrink_control *sc) 24297ae1749SKirill A. Shutemov { 24397ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 24497ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 24548896466SGlauber Costa } 24697ae1749SKirill A. Shutemov 24748896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 24848896466SGlauber Costa struct shrink_control *sc) 24948896466SGlauber Costa { 25097ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2515918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2525918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2535ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 25448896466SGlauber Costa return HPAGE_PMD_NR; 25597ae1749SKirill A. Shutemov } 25697ae1749SKirill A. Shutemov 25797ae1749SKirill A. Shutemov return 0; 25897ae1749SKirill A. Shutemov } 25997ae1749SKirill A. Shutemov 26097ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 26148896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 26248896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 26397ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 26497ae1749SKirill A. Shutemov }; 26597ae1749SKirill A. Shutemov 26671e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 267ba76149fSAndrea Arcangeli 26871e3aac0SAndrea Arcangeli static ssize_t double_flag_show(struct kobject *kobj, 26971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 27071e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 27171e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 27271e3aac0SAndrea Arcangeli { 27371e3aac0SAndrea Arcangeli if (test_bit(enabled, &transparent_hugepage_flags)) { 27471e3aac0SAndrea Arcangeli VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); 27571e3aac0SAndrea Arcangeli return sprintf(buf, "[always] madvise never\n"); 27671e3aac0SAndrea Arcangeli } else if (test_bit(req_madv, &transparent_hugepage_flags)) 27771e3aac0SAndrea Arcangeli return sprintf(buf, "always [madvise] never\n"); 27871e3aac0SAndrea Arcangeli else 27971e3aac0SAndrea Arcangeli return sprintf(buf, "always madvise [never]\n"); 28071e3aac0SAndrea Arcangeli } 28171e3aac0SAndrea Arcangeli static ssize_t double_flag_store(struct kobject *kobj, 28271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 28371e3aac0SAndrea Arcangeli const char *buf, size_t count, 28471e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 28571e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 28671e3aac0SAndrea Arcangeli { 28771e3aac0SAndrea Arcangeli if (!memcmp("always", buf, 28871e3aac0SAndrea Arcangeli min(sizeof("always")-1, count))) { 28971e3aac0SAndrea Arcangeli set_bit(enabled, &transparent_hugepage_flags); 29071e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 29171e3aac0SAndrea Arcangeli } else if (!memcmp("madvise", buf, 29271e3aac0SAndrea Arcangeli min(sizeof("madvise")-1, count))) { 29371e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 29471e3aac0SAndrea Arcangeli set_bit(req_madv, &transparent_hugepage_flags); 29571e3aac0SAndrea Arcangeli } else if (!memcmp("never", buf, 29671e3aac0SAndrea Arcangeli min(sizeof("never")-1, count))) { 29771e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 29871e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 29971e3aac0SAndrea Arcangeli } else 30071e3aac0SAndrea Arcangeli return -EINVAL; 30171e3aac0SAndrea Arcangeli 30271e3aac0SAndrea Arcangeli return count; 30371e3aac0SAndrea Arcangeli } 30471e3aac0SAndrea Arcangeli 30571e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 30671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 30771e3aac0SAndrea Arcangeli { 30871e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 30971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 31071e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 31171e3aac0SAndrea Arcangeli } 31271e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 31371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 31471e3aac0SAndrea Arcangeli const char *buf, size_t count) 31571e3aac0SAndrea Arcangeli { 316ba76149fSAndrea Arcangeli ssize_t ret; 317ba76149fSAndrea Arcangeli 318ba76149fSAndrea Arcangeli ret = double_flag_store(kobj, attr, buf, count, 31971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 32071e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 321ba76149fSAndrea Arcangeli 322ba76149fSAndrea Arcangeli if (ret > 0) { 323911891afSXiao Guangrong int err; 324911891afSXiao Guangrong 325911891afSXiao Guangrong mutex_lock(&khugepaged_mutex); 32679553da2SKirill A. Shutemov err = start_stop_khugepaged(); 327911891afSXiao Guangrong mutex_unlock(&khugepaged_mutex); 328911891afSXiao Guangrong 329ba76149fSAndrea Arcangeli if (err) 330ba76149fSAndrea Arcangeli ret = err; 331ba76149fSAndrea Arcangeli } 332ba76149fSAndrea Arcangeli 333ba76149fSAndrea Arcangeli return ret; 33471e3aac0SAndrea Arcangeli } 33571e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 33671e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 33771e3aac0SAndrea Arcangeli 33871e3aac0SAndrea Arcangeli static ssize_t single_flag_show(struct kobject *kobj, 33971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 34071e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 34171e3aac0SAndrea Arcangeli { 342e27e6151SBen Hutchings return sprintf(buf, "%d\n", 343e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 34471e3aac0SAndrea Arcangeli } 345e27e6151SBen Hutchings 34671e3aac0SAndrea Arcangeli static ssize_t single_flag_store(struct kobject *kobj, 34771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 34871e3aac0SAndrea Arcangeli const char *buf, size_t count, 34971e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 35071e3aac0SAndrea Arcangeli { 351e27e6151SBen Hutchings unsigned long value; 352e27e6151SBen Hutchings int ret; 353e27e6151SBen Hutchings 354e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 355e27e6151SBen Hutchings if (ret < 0) 356e27e6151SBen Hutchings return ret; 357e27e6151SBen Hutchings if (value > 1) 35871e3aac0SAndrea Arcangeli return -EINVAL; 35971e3aac0SAndrea Arcangeli 360e27e6151SBen Hutchings if (value) 361e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 362e27e6151SBen Hutchings else 363e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 364e27e6151SBen Hutchings 36571e3aac0SAndrea Arcangeli return count; 36671e3aac0SAndrea Arcangeli } 36771e3aac0SAndrea Arcangeli 36871e3aac0SAndrea Arcangeli /* 36971e3aac0SAndrea Arcangeli * Currently defrag only disables __GFP_NOWAIT for allocation. A blind 37071e3aac0SAndrea Arcangeli * __GFP_REPEAT is too aggressive, it's never worth swapping tons of 37171e3aac0SAndrea Arcangeli * memory just to allocate one more hugepage. 37271e3aac0SAndrea Arcangeli */ 37371e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 37471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 37571e3aac0SAndrea Arcangeli { 37671e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 37771e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 37871e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 37971e3aac0SAndrea Arcangeli } 38071e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 38171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 38271e3aac0SAndrea Arcangeli const char *buf, size_t count) 38371e3aac0SAndrea Arcangeli { 38471e3aac0SAndrea Arcangeli return double_flag_store(kobj, attr, buf, count, 38571e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 38671e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 38771e3aac0SAndrea Arcangeli } 38871e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 38971e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 39071e3aac0SAndrea Arcangeli 39179da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 39279da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 39379da5407SKirill A. Shutemov { 39479da5407SKirill A. Shutemov return single_flag_show(kobj, attr, buf, 39579da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 39679da5407SKirill A. Shutemov } 39779da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 39879da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 39979da5407SKirill A. Shutemov { 40079da5407SKirill A. Shutemov return single_flag_store(kobj, attr, buf, count, 40179da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 40279da5407SKirill A. Shutemov } 40379da5407SKirill A. Shutemov static struct kobj_attribute use_zero_page_attr = 40479da5407SKirill A. Shutemov __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); 40571e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 40671e3aac0SAndrea Arcangeli static ssize_t debug_cow_show(struct kobject *kobj, 40771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 40871e3aac0SAndrea Arcangeli { 40971e3aac0SAndrea Arcangeli return single_flag_show(kobj, attr, buf, 41071e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 41171e3aac0SAndrea Arcangeli } 41271e3aac0SAndrea Arcangeli static ssize_t debug_cow_store(struct kobject *kobj, 41371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 41471e3aac0SAndrea Arcangeli const char *buf, size_t count) 41571e3aac0SAndrea Arcangeli { 41671e3aac0SAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 41771e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 41871e3aac0SAndrea Arcangeli } 41971e3aac0SAndrea Arcangeli static struct kobj_attribute debug_cow_attr = 42071e3aac0SAndrea Arcangeli __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); 42171e3aac0SAndrea Arcangeli #endif /* CONFIG_DEBUG_VM */ 42271e3aac0SAndrea Arcangeli 42371e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 42471e3aac0SAndrea Arcangeli &enabled_attr.attr, 42571e3aac0SAndrea Arcangeli &defrag_attr.attr, 42679da5407SKirill A. Shutemov &use_zero_page_attr.attr, 42771e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 42871e3aac0SAndrea Arcangeli &debug_cow_attr.attr, 42971e3aac0SAndrea Arcangeli #endif 43071e3aac0SAndrea Arcangeli NULL, 43171e3aac0SAndrea Arcangeli }; 43271e3aac0SAndrea Arcangeli 43371e3aac0SAndrea Arcangeli static struct attribute_group hugepage_attr_group = { 43471e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 435ba76149fSAndrea Arcangeli }; 436ba76149fSAndrea Arcangeli 437ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, 438ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 439ba76149fSAndrea Arcangeli char *buf) 440ba76149fSAndrea Arcangeli { 441ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); 442ba76149fSAndrea Arcangeli } 443ba76149fSAndrea Arcangeli 444ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, 445ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 446ba76149fSAndrea Arcangeli const char *buf, size_t count) 447ba76149fSAndrea Arcangeli { 448ba76149fSAndrea Arcangeli unsigned long msecs; 449ba76149fSAndrea Arcangeli int err; 450ba76149fSAndrea Arcangeli 4513dbb95f7SJingoo Han err = kstrtoul(buf, 10, &msecs); 452ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 453ba76149fSAndrea Arcangeli return -EINVAL; 454ba76149fSAndrea Arcangeli 455ba76149fSAndrea Arcangeli khugepaged_scan_sleep_millisecs = msecs; 456ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 457ba76149fSAndrea Arcangeli 458ba76149fSAndrea Arcangeli return count; 459ba76149fSAndrea Arcangeli } 460ba76149fSAndrea Arcangeli static struct kobj_attribute scan_sleep_millisecs_attr = 461ba76149fSAndrea Arcangeli __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, 462ba76149fSAndrea Arcangeli scan_sleep_millisecs_store); 463ba76149fSAndrea Arcangeli 464ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, 465ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 466ba76149fSAndrea Arcangeli char *buf) 467ba76149fSAndrea Arcangeli { 468ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); 469ba76149fSAndrea Arcangeli } 470ba76149fSAndrea Arcangeli 471ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, 472ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 473ba76149fSAndrea Arcangeli const char *buf, size_t count) 474ba76149fSAndrea Arcangeli { 475ba76149fSAndrea Arcangeli unsigned long msecs; 476ba76149fSAndrea Arcangeli int err; 477ba76149fSAndrea Arcangeli 4783dbb95f7SJingoo Han err = kstrtoul(buf, 10, &msecs); 479ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 480ba76149fSAndrea Arcangeli return -EINVAL; 481ba76149fSAndrea Arcangeli 482ba76149fSAndrea Arcangeli khugepaged_alloc_sleep_millisecs = msecs; 483ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 484ba76149fSAndrea Arcangeli 485ba76149fSAndrea Arcangeli return count; 486ba76149fSAndrea Arcangeli } 487ba76149fSAndrea Arcangeli static struct kobj_attribute alloc_sleep_millisecs_attr = 488ba76149fSAndrea Arcangeli __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, 489ba76149fSAndrea Arcangeli alloc_sleep_millisecs_store); 490ba76149fSAndrea Arcangeli 491ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_show(struct kobject *kobj, 492ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 493ba76149fSAndrea Arcangeli char *buf) 494ba76149fSAndrea Arcangeli { 495ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_to_scan); 496ba76149fSAndrea Arcangeli } 497ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_store(struct kobject *kobj, 498ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 499ba76149fSAndrea Arcangeli const char *buf, size_t count) 500ba76149fSAndrea Arcangeli { 501ba76149fSAndrea Arcangeli int err; 502ba76149fSAndrea Arcangeli unsigned long pages; 503ba76149fSAndrea Arcangeli 5043dbb95f7SJingoo Han err = kstrtoul(buf, 10, &pages); 505ba76149fSAndrea Arcangeli if (err || !pages || pages > UINT_MAX) 506ba76149fSAndrea Arcangeli return -EINVAL; 507ba76149fSAndrea Arcangeli 508ba76149fSAndrea Arcangeli khugepaged_pages_to_scan = pages; 509ba76149fSAndrea Arcangeli 510ba76149fSAndrea Arcangeli return count; 511ba76149fSAndrea Arcangeli } 512ba76149fSAndrea Arcangeli static struct kobj_attribute pages_to_scan_attr = 513ba76149fSAndrea Arcangeli __ATTR(pages_to_scan, 0644, pages_to_scan_show, 514ba76149fSAndrea Arcangeli pages_to_scan_store); 515ba76149fSAndrea Arcangeli 516ba76149fSAndrea Arcangeli static ssize_t pages_collapsed_show(struct kobject *kobj, 517ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 518ba76149fSAndrea Arcangeli char *buf) 519ba76149fSAndrea Arcangeli { 520ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_collapsed); 521ba76149fSAndrea Arcangeli } 522ba76149fSAndrea Arcangeli static struct kobj_attribute pages_collapsed_attr = 523ba76149fSAndrea Arcangeli __ATTR_RO(pages_collapsed); 524ba76149fSAndrea Arcangeli 525ba76149fSAndrea Arcangeli static ssize_t full_scans_show(struct kobject *kobj, 526ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 527ba76149fSAndrea Arcangeli char *buf) 528ba76149fSAndrea Arcangeli { 529ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_full_scans); 530ba76149fSAndrea Arcangeli } 531ba76149fSAndrea Arcangeli static struct kobj_attribute full_scans_attr = 532ba76149fSAndrea Arcangeli __ATTR_RO(full_scans); 533ba76149fSAndrea Arcangeli 534ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_show(struct kobject *kobj, 535ba76149fSAndrea Arcangeli struct kobj_attribute *attr, char *buf) 536ba76149fSAndrea Arcangeli { 537ba76149fSAndrea Arcangeli return single_flag_show(kobj, attr, buf, 538ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 539ba76149fSAndrea Arcangeli } 540ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_store(struct kobject *kobj, 541ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 542ba76149fSAndrea Arcangeli const char *buf, size_t count) 543ba76149fSAndrea Arcangeli { 544ba76149fSAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 545ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 546ba76149fSAndrea Arcangeli } 547ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_defrag_attr = 548ba76149fSAndrea Arcangeli __ATTR(defrag, 0644, khugepaged_defrag_show, 549ba76149fSAndrea Arcangeli khugepaged_defrag_store); 550ba76149fSAndrea Arcangeli 551ba76149fSAndrea Arcangeli /* 552ba76149fSAndrea Arcangeli * max_ptes_none controls if khugepaged should collapse hugepages over 553ba76149fSAndrea Arcangeli * any unmapped ptes in turn potentially increasing the memory 554ba76149fSAndrea Arcangeli * footprint of the vmas. When max_ptes_none is 0 khugepaged will not 555ba76149fSAndrea Arcangeli * reduce the available free memory in the system as it 556ba76149fSAndrea Arcangeli * runs. Increasing max_ptes_none will instead potentially reduce the 557ba76149fSAndrea Arcangeli * free memory in the system during the khugepaged scan. 558ba76149fSAndrea Arcangeli */ 559ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, 560ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 561ba76149fSAndrea Arcangeli char *buf) 562ba76149fSAndrea Arcangeli { 563ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_max_ptes_none); 564ba76149fSAndrea Arcangeli } 565ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, 566ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 567ba76149fSAndrea Arcangeli const char *buf, size_t count) 568ba76149fSAndrea Arcangeli { 569ba76149fSAndrea Arcangeli int err; 570ba76149fSAndrea Arcangeli unsigned long max_ptes_none; 571ba76149fSAndrea Arcangeli 5723dbb95f7SJingoo Han err = kstrtoul(buf, 10, &max_ptes_none); 573ba76149fSAndrea Arcangeli if (err || max_ptes_none > HPAGE_PMD_NR-1) 574ba76149fSAndrea Arcangeli return -EINVAL; 575ba76149fSAndrea Arcangeli 576ba76149fSAndrea Arcangeli khugepaged_max_ptes_none = max_ptes_none; 577ba76149fSAndrea Arcangeli 578ba76149fSAndrea Arcangeli return count; 579ba76149fSAndrea Arcangeli } 580ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_max_ptes_none_attr = 581ba76149fSAndrea Arcangeli __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, 582ba76149fSAndrea Arcangeli khugepaged_max_ptes_none_store); 583ba76149fSAndrea Arcangeli 584ba76149fSAndrea Arcangeli static struct attribute *khugepaged_attr[] = { 585ba76149fSAndrea Arcangeli &khugepaged_defrag_attr.attr, 586ba76149fSAndrea Arcangeli &khugepaged_max_ptes_none_attr.attr, 587ba76149fSAndrea Arcangeli &pages_to_scan_attr.attr, 588ba76149fSAndrea Arcangeli &pages_collapsed_attr.attr, 589ba76149fSAndrea Arcangeli &full_scans_attr.attr, 590ba76149fSAndrea Arcangeli &scan_sleep_millisecs_attr.attr, 591ba76149fSAndrea Arcangeli &alloc_sleep_millisecs_attr.attr, 592ba76149fSAndrea Arcangeli NULL, 593ba76149fSAndrea Arcangeli }; 594ba76149fSAndrea Arcangeli 595ba76149fSAndrea Arcangeli static struct attribute_group khugepaged_attr_group = { 596ba76149fSAndrea Arcangeli .attrs = khugepaged_attr, 597ba76149fSAndrea Arcangeli .name = "khugepaged", 59871e3aac0SAndrea Arcangeli }; 599569e5590SShaohua Li 600569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 601569e5590SShaohua Li { 602569e5590SShaohua Li int err; 603569e5590SShaohua Li 604569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 605569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 606ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 607569e5590SShaohua Li return -ENOMEM; 608569e5590SShaohua Li } 609569e5590SShaohua Li 610569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 611569e5590SShaohua Li if (err) { 612ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 613569e5590SShaohua Li goto delete_obj; 614569e5590SShaohua Li } 615569e5590SShaohua Li 616569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 617569e5590SShaohua Li if (err) { 618ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 619569e5590SShaohua Li goto remove_hp_group; 620569e5590SShaohua Li } 621569e5590SShaohua Li 622569e5590SShaohua Li return 0; 623569e5590SShaohua Li 624569e5590SShaohua Li remove_hp_group: 625569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 626569e5590SShaohua Li delete_obj: 627569e5590SShaohua Li kobject_put(*hugepage_kobj); 628569e5590SShaohua Li return err; 629569e5590SShaohua Li } 630569e5590SShaohua Li 631569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 632569e5590SShaohua Li { 633569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 634569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 635569e5590SShaohua Li kobject_put(hugepage_kobj); 636569e5590SShaohua Li } 637569e5590SShaohua Li #else 638569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 639569e5590SShaohua Li { 640569e5590SShaohua Li return 0; 641569e5590SShaohua Li } 642569e5590SShaohua Li 643569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 644569e5590SShaohua Li { 645569e5590SShaohua Li } 64671e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 64771e3aac0SAndrea Arcangeli 64871e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 64971e3aac0SAndrea Arcangeli { 65071e3aac0SAndrea Arcangeli int err; 651569e5590SShaohua Li struct kobject *hugepage_kobj; 65271e3aac0SAndrea Arcangeli 6534b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 6544b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 655569e5590SShaohua Li return -EINVAL; 6564b7167b9SAndrea Arcangeli } 6574b7167b9SAndrea Arcangeli 658569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 659569e5590SShaohua Li if (err) 66065ebb64fSKirill A. Shutemov goto err_sysfs; 661ba76149fSAndrea Arcangeli 662ba76149fSAndrea Arcangeli err = khugepaged_slab_init(); 663ba76149fSAndrea Arcangeli if (err) 66465ebb64fSKirill A. Shutemov goto err_slab; 665ba76149fSAndrea Arcangeli 66665ebb64fSKirill A. Shutemov err = register_shrinker(&huge_zero_page_shrinker); 66765ebb64fSKirill A. Shutemov if (err) 66865ebb64fSKirill A. Shutemov goto err_hzp_shrinker; 66997ae1749SKirill A. Shutemov 67097562cd2SRik van Riel /* 67197562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 67297562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 67397562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 67497562cd2SRik van Riel */ 67579553da2SKirill A. Shutemov if (totalram_pages < (512 << (20 - PAGE_SHIFT))) { 67697562cd2SRik van Riel transparent_hugepage_flags = 0; 67779553da2SKirill A. Shutemov return 0; 67879553da2SKirill A. Shutemov } 67997562cd2SRik van Riel 68079553da2SKirill A. Shutemov err = start_stop_khugepaged(); 68165ebb64fSKirill A. Shutemov if (err) 68265ebb64fSKirill A. Shutemov goto err_khugepaged; 683ba76149fSAndrea Arcangeli 684569e5590SShaohua Li return 0; 68565ebb64fSKirill A. Shutemov err_khugepaged: 68665ebb64fSKirill A. Shutemov unregister_shrinker(&huge_zero_page_shrinker); 68765ebb64fSKirill A. Shutemov err_hzp_shrinker: 68865ebb64fSKirill A. Shutemov khugepaged_slab_exit(); 68965ebb64fSKirill A. Shutemov err_slab: 690569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 69165ebb64fSKirill A. Shutemov err_sysfs: 692ba76149fSAndrea Arcangeli return err; 69371e3aac0SAndrea Arcangeli } 694a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 69571e3aac0SAndrea Arcangeli 69671e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 69771e3aac0SAndrea Arcangeli { 69871e3aac0SAndrea Arcangeli int ret = 0; 69971e3aac0SAndrea Arcangeli if (!str) 70071e3aac0SAndrea Arcangeli goto out; 70171e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 70271e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 70371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 70471e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 70571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 70671e3aac0SAndrea Arcangeli ret = 1; 70771e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 70871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 70971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 71071e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 71171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 71271e3aac0SAndrea Arcangeli ret = 1; 71371e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 71471e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 71571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 71671e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 71771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 71871e3aac0SAndrea Arcangeli ret = 1; 71971e3aac0SAndrea Arcangeli } 72071e3aac0SAndrea Arcangeli out: 72171e3aac0SAndrea Arcangeli if (!ret) 722ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 72371e3aac0SAndrea Arcangeli return ret; 72471e3aac0SAndrea Arcangeli } 72571e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 72671e3aac0SAndrea Arcangeli 727b32967ffSMel Gorman pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 72871e3aac0SAndrea Arcangeli { 72971e3aac0SAndrea Arcangeli if (likely(vma->vm_flags & VM_WRITE)) 73071e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 73171e3aac0SAndrea Arcangeli return pmd; 73271e3aac0SAndrea Arcangeli } 73371e3aac0SAndrea Arcangeli 7343122359aSKirill A. Shutemov static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot) 735b3092b3bSBob Liu { 736b3092b3bSBob Liu pmd_t entry; 7373122359aSKirill A. Shutemov entry = mk_pmd(page, prot); 738b3092b3bSBob Liu entry = pmd_mkhuge(entry); 739b3092b3bSBob Liu return entry; 740b3092b3bSBob Liu } 741b3092b3bSBob Liu 74271e3aac0SAndrea Arcangeli static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, 74371e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 744230c92a8SAndrea Arcangeli unsigned long address, pmd_t *pmd, 7456b251fc9SAndrea Arcangeli struct page *page, gfp_t gfp, 7466b251fc9SAndrea Arcangeli unsigned int flags) 74771e3aac0SAndrea Arcangeli { 74800501b53SJohannes Weiner struct mem_cgroup *memcg; 74971e3aac0SAndrea Arcangeli pgtable_t pgtable; 750c4088ebdSKirill A. Shutemov spinlock_t *ptl; 751230c92a8SAndrea Arcangeli unsigned long haddr = address & HPAGE_PMD_MASK; 75271e3aac0SAndrea Arcangeli 753309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 75400501b53SJohannes Weiner 755f627c2f5SKirill A. Shutemov if (mem_cgroup_try_charge(page, mm, gfp, &memcg, true)) { 7566b251fc9SAndrea Arcangeli put_page(page); 7576b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 7586b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 7596b251fc9SAndrea Arcangeli } 76071e3aac0SAndrea Arcangeli 76100501b53SJohannes Weiner pgtable = pte_alloc_one(mm, haddr); 76200501b53SJohannes Weiner if (unlikely(!pgtable)) { 763f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, true); 7646b251fc9SAndrea Arcangeli put_page(page); 76500501b53SJohannes Weiner return VM_FAULT_OOM; 76600501b53SJohannes Weiner } 76700501b53SJohannes Weiner 76871e3aac0SAndrea Arcangeli clear_huge_page(page, haddr, HPAGE_PMD_NR); 76952f37629SMinchan Kim /* 77052f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 77152f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 77252f37629SMinchan Kim * write. 77352f37629SMinchan Kim */ 77471e3aac0SAndrea Arcangeli __SetPageUptodate(page); 77571e3aac0SAndrea Arcangeli 776c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 77771e3aac0SAndrea Arcangeli if (unlikely(!pmd_none(*pmd))) { 778c4088ebdSKirill A. Shutemov spin_unlock(ptl); 779f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, true); 78071e3aac0SAndrea Arcangeli put_page(page); 78171e3aac0SAndrea Arcangeli pte_free(mm, pgtable); 78271e3aac0SAndrea Arcangeli } else { 78371e3aac0SAndrea Arcangeli pmd_t entry; 7846b251fc9SAndrea Arcangeli 7856b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 7866b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 7876b251fc9SAndrea Arcangeli int ret; 7886b251fc9SAndrea Arcangeli 7896b251fc9SAndrea Arcangeli spin_unlock(ptl); 790f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, true); 7916b251fc9SAndrea Arcangeli put_page(page); 7926b251fc9SAndrea Arcangeli pte_free(mm, pgtable); 793230c92a8SAndrea Arcangeli ret = handle_userfault(vma, address, flags, 7946b251fc9SAndrea Arcangeli VM_UFFD_MISSING); 7956b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 7966b251fc9SAndrea Arcangeli return ret; 7976b251fc9SAndrea Arcangeli } 7986b251fc9SAndrea Arcangeli 7993122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 8003122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 801d281ee61SKirill A. Shutemov page_add_new_anon_rmap(page, vma, haddr, true); 802f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(page, memcg, false, true); 80300501b53SJohannes Weiner lru_cache_add_active_or_unevictable(page, vma); 8046b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 80571e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 80671e3aac0SAndrea Arcangeli add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 807e1f56c89SKirill A. Shutemov atomic_long_inc(&mm->nr_ptes); 808c4088ebdSKirill A. Shutemov spin_unlock(ptl); 8096b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 81071e3aac0SAndrea Arcangeli } 81171e3aac0SAndrea Arcangeli 812aa2e878eSDavid Rientjes return 0; 81371e3aac0SAndrea Arcangeli } 81471e3aac0SAndrea Arcangeli 815cc5d462fSAndi Kleen static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) 8160bbbc0b3SAndrea Arcangeli { 81771baba4bSMel Gorman return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_RECLAIM)) | extra_gfp; 8180bbbc0b3SAndrea Arcangeli } 8190bbbc0b3SAndrea Arcangeli 820c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 821d295e341SKirill A. Shutemov static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 82297ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 8235918d10aSKirill A. Shutemov struct page *zero_page) 824fc9fe822SKirill A. Shutemov { 825fc9fe822SKirill A. Shutemov pmd_t entry; 8267c414164SAndrew Morton if (!pmd_none(*pmd)) 8277c414164SAndrew Morton return false; 8285918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 829fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 8306b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 831fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 832e1f56c89SKirill A. Shutemov atomic_long_inc(&mm->nr_ptes); 8337c414164SAndrew Morton return true; 834fc9fe822SKirill A. Shutemov } 835fc9fe822SKirill A. Shutemov 83671e3aac0SAndrea Arcangeli int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 83771e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, 83871e3aac0SAndrea Arcangeli unsigned int flags) 83971e3aac0SAndrea Arcangeli { 840077fcf11SAneesh Kumar K.V gfp_t gfp; 84171e3aac0SAndrea Arcangeli struct page *page; 84271e3aac0SAndrea Arcangeli unsigned long haddr = address & HPAGE_PMD_MASK; 84371e3aac0SAndrea Arcangeli 844128ec037SKirill A. Shutemov if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) 845c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 8467479df6dSKirill A. Shutemov if (vma->vm_flags & VM_LOCKED) 8477479df6dSKirill A. Shutemov return VM_FAULT_FALLBACK; 84871e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 84971e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 8506d50e60cSDavid Rientjes if (unlikely(khugepaged_enter(vma, vma->vm_flags))) 851ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 852593befa6SDominik Dingel if (!(flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(mm) && 85379da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 854c4088ebdSKirill A. Shutemov spinlock_t *ptl; 85580371957SKirill A. Shutemov pgtable_t pgtable; 8565918d10aSKirill A. Shutemov struct page *zero_page; 8573ea41e62SKirill A. Shutemov bool set; 8586b251fc9SAndrea Arcangeli int ret; 85980371957SKirill A. Shutemov pgtable = pte_alloc_one(mm, haddr); 86080371957SKirill A. Shutemov if (unlikely(!pgtable)) 86180371957SKirill A. Shutemov return VM_FAULT_OOM; 8625918d10aSKirill A. Shutemov zero_page = get_huge_zero_page(); 8635918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 86497ae1749SKirill A. Shutemov pte_free(mm, pgtable); 86597ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 866c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 86797ae1749SKirill A. Shutemov } 868c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 8696b251fc9SAndrea Arcangeli ret = 0; 8706b251fc9SAndrea Arcangeli set = false; 8716b251fc9SAndrea Arcangeli if (pmd_none(*pmd)) { 8726b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 8736b251fc9SAndrea Arcangeli spin_unlock(ptl); 874230c92a8SAndrea Arcangeli ret = handle_userfault(vma, address, flags, 8756b251fc9SAndrea Arcangeli VM_UFFD_MISSING); 8766b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 8776b251fc9SAndrea Arcangeli } else { 8786b251fc9SAndrea Arcangeli set_huge_zero_page(pgtable, mm, vma, 8796b251fc9SAndrea Arcangeli haddr, pmd, 8805918d10aSKirill A. Shutemov zero_page); 881c4088ebdSKirill A. Shutemov spin_unlock(ptl); 8826b251fc9SAndrea Arcangeli set = true; 8836b251fc9SAndrea Arcangeli } 8846b251fc9SAndrea Arcangeli } else 8856b251fc9SAndrea Arcangeli spin_unlock(ptl); 8863ea41e62SKirill A. Shutemov if (!set) { 8873ea41e62SKirill A. Shutemov pte_free(mm, pgtable); 8883ea41e62SKirill A. Shutemov put_huge_zero_page(); 8893ea41e62SKirill A. Shutemov } 8906b251fc9SAndrea Arcangeli return ret; 89180371957SKirill A. Shutemov } 892077fcf11SAneesh Kumar K.V gfp = alloc_hugepage_gfpmask(transparent_hugepage_defrag(vma), 0); 893077fcf11SAneesh Kumar K.V page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); 89481ab4201SAndi Kleen if (unlikely(!page)) { 89581ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 896c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 89781ab4201SAndi Kleen } 898230c92a8SAndrea Arcangeli return __do_huge_pmd_anonymous_page(mm, vma, address, pmd, page, gfp, 899230c92a8SAndrea Arcangeli flags); 90071e3aac0SAndrea Arcangeli } 90171e3aac0SAndrea Arcangeli 902ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 9035cad465dSMatthew Wilcox pmd_t *pmd, unsigned long pfn, pgprot_t prot, bool write) 9045cad465dSMatthew Wilcox { 9055cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 9065cad465dSMatthew Wilcox pmd_t entry; 9075cad465dSMatthew Wilcox spinlock_t *ptl; 9085cad465dSMatthew Wilcox 9095cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 9105cad465dSMatthew Wilcox if (pmd_none(*pmd)) { 9115cad465dSMatthew Wilcox entry = pmd_mkhuge(pfn_pmd(pfn, prot)); 9125cad465dSMatthew Wilcox if (write) { 9135cad465dSMatthew Wilcox entry = pmd_mkyoung(pmd_mkdirty(entry)); 9145cad465dSMatthew Wilcox entry = maybe_pmd_mkwrite(entry, vma); 9155cad465dSMatthew Wilcox } 9165cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 9175cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 9185cad465dSMatthew Wilcox } 9195cad465dSMatthew Wilcox spin_unlock(ptl); 9205cad465dSMatthew Wilcox } 9215cad465dSMatthew Wilcox 9225cad465dSMatthew Wilcox int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 9235cad465dSMatthew Wilcox pmd_t *pmd, unsigned long pfn, bool write) 9245cad465dSMatthew Wilcox { 9255cad465dSMatthew Wilcox pgprot_t pgprot = vma->vm_page_prot; 9265cad465dSMatthew Wilcox /* 9275cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 9285cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 9295cad465dSMatthew Wilcox * can't support a 'special' bit. 9305cad465dSMatthew Wilcox */ 9315cad465dSMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 9325cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 9335cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 9345cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 9355cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 9365cad465dSMatthew Wilcox 9375cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 9385cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 9395cad465dSMatthew Wilcox if (track_pfn_insert(vma, &pgprot, pfn)) 9405cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 941ae18d6dcSMatthew Wilcox insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write); 942ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 9435cad465dSMatthew Wilcox } 9445cad465dSMatthew Wilcox 94571e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 94671e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 94771e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 94871e3aac0SAndrea Arcangeli { 949c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 95071e3aac0SAndrea Arcangeli struct page *src_page; 95171e3aac0SAndrea Arcangeli pmd_t pmd; 95271e3aac0SAndrea Arcangeli pgtable_t pgtable; 95371e3aac0SAndrea Arcangeli int ret; 95471e3aac0SAndrea Arcangeli 95571e3aac0SAndrea Arcangeli ret = -ENOMEM; 95671e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(dst_mm, addr); 95771e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 95871e3aac0SAndrea Arcangeli goto out; 95971e3aac0SAndrea Arcangeli 960c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 961c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 962c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 96371e3aac0SAndrea Arcangeli 96471e3aac0SAndrea Arcangeli ret = -EAGAIN; 96571e3aac0SAndrea Arcangeli pmd = *src_pmd; 96671e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(pmd))) { 96771e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 96871e3aac0SAndrea Arcangeli goto out_unlock; 96971e3aac0SAndrea Arcangeli } 970fc9fe822SKirill A. Shutemov /* 971c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 972fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 973fc9fe822SKirill A. Shutemov * a page table. 974fc9fe822SKirill A. Shutemov */ 975fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 9765918d10aSKirill A. Shutemov struct page *zero_page; 97797ae1749SKirill A. Shutemov /* 97897ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 97997ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 98097ae1749SKirill A. Shutemov * reference. 98197ae1749SKirill A. Shutemov */ 9825918d10aSKirill A. Shutemov zero_page = get_huge_zero_page(); 9836b251fc9SAndrea Arcangeli set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, 9845918d10aSKirill A. Shutemov zero_page); 985fc9fe822SKirill A. Shutemov ret = 0; 986fc9fe822SKirill A. Shutemov goto out_unlock; 987fc9fe822SKirill A. Shutemov } 988de466bd6SMel Gorman 98971e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 990309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 99171e3aac0SAndrea Arcangeli get_page(src_page); 99271e3aac0SAndrea Arcangeli page_dup_rmap(src_page); 99371e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 99471e3aac0SAndrea Arcangeli 99571e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 99671e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 9976b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 99871e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 999e1f56c89SKirill A. Shutemov atomic_long_inc(&dst_mm->nr_ptes); 100071e3aac0SAndrea Arcangeli 100171e3aac0SAndrea Arcangeli ret = 0; 100271e3aac0SAndrea Arcangeli out_unlock: 1003c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 1004c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 100571e3aac0SAndrea Arcangeli out: 100671e3aac0SAndrea Arcangeli return ret; 100771e3aac0SAndrea Arcangeli } 100871e3aac0SAndrea Arcangeli 1009a1dd450bSWill Deacon void huge_pmd_set_accessed(struct mm_struct *mm, 1010a1dd450bSWill Deacon struct vm_area_struct *vma, 1011a1dd450bSWill Deacon unsigned long address, 1012a1dd450bSWill Deacon pmd_t *pmd, pmd_t orig_pmd, 1013a1dd450bSWill Deacon int dirty) 1014a1dd450bSWill Deacon { 1015c4088ebdSKirill A. Shutemov spinlock_t *ptl; 1016a1dd450bSWill Deacon pmd_t entry; 1017a1dd450bSWill Deacon unsigned long haddr; 1018a1dd450bSWill Deacon 1019c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 1020a1dd450bSWill Deacon if (unlikely(!pmd_same(*pmd, orig_pmd))) 1021a1dd450bSWill Deacon goto unlock; 1022a1dd450bSWill Deacon 1023a1dd450bSWill Deacon entry = pmd_mkyoung(orig_pmd); 1024a1dd450bSWill Deacon haddr = address & HPAGE_PMD_MASK; 1025a1dd450bSWill Deacon if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) 1026a1dd450bSWill Deacon update_mmu_cache_pmd(vma, address, pmd); 1027a1dd450bSWill Deacon 1028a1dd450bSWill Deacon unlock: 1029c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1030a1dd450bSWill Deacon } 1031a1dd450bSWill Deacon 103271e3aac0SAndrea Arcangeli static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, 103371e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 103471e3aac0SAndrea Arcangeli unsigned long address, 103571e3aac0SAndrea Arcangeli pmd_t *pmd, pmd_t orig_pmd, 103671e3aac0SAndrea Arcangeli struct page *page, 103771e3aac0SAndrea Arcangeli unsigned long haddr) 103871e3aac0SAndrea Arcangeli { 103900501b53SJohannes Weiner struct mem_cgroup *memcg; 1040c4088ebdSKirill A. Shutemov spinlock_t *ptl; 104171e3aac0SAndrea Arcangeli pgtable_t pgtable; 104271e3aac0SAndrea Arcangeli pmd_t _pmd; 104371e3aac0SAndrea Arcangeli int ret = 0, i; 104471e3aac0SAndrea Arcangeli struct page **pages; 10452ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 10462ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 104771e3aac0SAndrea Arcangeli 104871e3aac0SAndrea Arcangeli pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, 104971e3aac0SAndrea Arcangeli GFP_KERNEL); 105071e3aac0SAndrea Arcangeli if (unlikely(!pages)) { 105171e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 105271e3aac0SAndrea Arcangeli goto out; 105371e3aac0SAndrea Arcangeli } 105471e3aac0SAndrea Arcangeli 105571e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 1056cc5d462fSAndi Kleen pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | 1057cc5d462fSAndi Kleen __GFP_OTHER_NODE, 105819ee151eSAndi Kleen vma, address, page_to_nid(page)); 1059b9bbfbe3SAndrea Arcangeli if (unlikely(!pages[i] || 106000501b53SJohannes Weiner mem_cgroup_try_charge(pages[i], mm, GFP_KERNEL, 1061f627c2f5SKirill A. Shutemov &memcg, false))) { 1062b9bbfbe3SAndrea Arcangeli if (pages[i]) 106371e3aac0SAndrea Arcangeli put_page(pages[i]); 1064b9bbfbe3SAndrea Arcangeli while (--i >= 0) { 106500501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 106600501b53SJohannes Weiner set_page_private(pages[i], 0); 1067f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(pages[i], memcg, 1068f627c2f5SKirill A. Shutemov false); 1069b9bbfbe3SAndrea Arcangeli put_page(pages[i]); 1070b9bbfbe3SAndrea Arcangeli } 107171e3aac0SAndrea Arcangeli kfree(pages); 107271e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 107371e3aac0SAndrea Arcangeli goto out; 107471e3aac0SAndrea Arcangeli } 107500501b53SJohannes Weiner set_page_private(pages[i], (unsigned long)memcg); 107671e3aac0SAndrea Arcangeli } 107771e3aac0SAndrea Arcangeli 107871e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 107971e3aac0SAndrea Arcangeli copy_user_highpage(pages[i], page + i, 10800089e485SHillf Danton haddr + PAGE_SIZE * i, vma); 108171e3aac0SAndrea Arcangeli __SetPageUptodate(pages[i]); 108271e3aac0SAndrea Arcangeli cond_resched(); 108371e3aac0SAndrea Arcangeli } 108471e3aac0SAndrea Arcangeli 10852ec74c3eSSagi Grimberg mmun_start = haddr; 10862ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 10872ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 10882ec74c3eSSagi Grimberg 1089c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 109071e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 109171e3aac0SAndrea Arcangeli goto out_free_pages; 1092309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 109371e3aac0SAndrea Arcangeli 10948809aa2dSAneesh Kumar K.V pmdp_huge_clear_flush_notify(vma, haddr, pmd); 109571e3aac0SAndrea Arcangeli /* leave pmd empty until pte is filled */ 109671e3aac0SAndrea Arcangeli 10976b0b50b0SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 109871e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 109971e3aac0SAndrea Arcangeli 110071e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 110171e3aac0SAndrea Arcangeli pte_t *pte, entry; 110271e3aac0SAndrea Arcangeli entry = mk_pte(pages[i], vma->vm_page_prot); 110371e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 110400501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 110500501b53SJohannes Weiner set_page_private(pages[i], 0); 1106d281ee61SKirill A. Shutemov page_add_new_anon_rmap(pages[i], vma, haddr, false); 1107f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(pages[i], memcg, false, false); 110800501b53SJohannes Weiner lru_cache_add_active_or_unevictable(pages[i], vma); 110971e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 111071e3aac0SAndrea Arcangeli VM_BUG_ON(!pte_none(*pte)); 111171e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 111271e3aac0SAndrea Arcangeli pte_unmap(pte); 111371e3aac0SAndrea Arcangeli } 111471e3aac0SAndrea Arcangeli kfree(pages); 111571e3aac0SAndrea Arcangeli 111671e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 111771e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 1118d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 1119c4088ebdSKirill A. Shutemov spin_unlock(ptl); 112071e3aac0SAndrea Arcangeli 11212ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 11222ec74c3eSSagi Grimberg 112371e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 112471e3aac0SAndrea Arcangeli put_page(page); 112571e3aac0SAndrea Arcangeli 112671e3aac0SAndrea Arcangeli out: 112771e3aac0SAndrea Arcangeli return ret; 112871e3aac0SAndrea Arcangeli 112971e3aac0SAndrea Arcangeli out_free_pages: 1130c4088ebdSKirill A. Shutemov spin_unlock(ptl); 11312ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 1132b9bbfbe3SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 113300501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 113400501b53SJohannes Weiner set_page_private(pages[i], 0); 1135f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(pages[i], memcg, false); 113671e3aac0SAndrea Arcangeli put_page(pages[i]); 1137b9bbfbe3SAndrea Arcangeli } 113871e3aac0SAndrea Arcangeli kfree(pages); 113971e3aac0SAndrea Arcangeli goto out; 114071e3aac0SAndrea Arcangeli } 114171e3aac0SAndrea Arcangeli 114271e3aac0SAndrea Arcangeli int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 114371e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, pmd_t orig_pmd) 114471e3aac0SAndrea Arcangeli { 1145c4088ebdSKirill A. Shutemov spinlock_t *ptl; 114671e3aac0SAndrea Arcangeli int ret = 0; 114793b4796dSKirill A. Shutemov struct page *page = NULL, *new_page; 114800501b53SJohannes Weiner struct mem_cgroup *memcg; 114971e3aac0SAndrea Arcangeli unsigned long haddr; 11502ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 11512ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 11523b363692SMichal Hocko gfp_t huge_gfp; /* for allocation and charge */ 115371e3aac0SAndrea Arcangeli 1154c4088ebdSKirill A. Shutemov ptl = pmd_lockptr(mm, pmd); 115581d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 115693b4796dSKirill A. Shutemov haddr = address & HPAGE_PMD_MASK; 115793b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 115893b4796dSKirill A. Shutemov goto alloc; 1159c4088ebdSKirill A. Shutemov spin_lock(ptl); 116071e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 116171e3aac0SAndrea Arcangeli goto out_unlock; 116271e3aac0SAndrea Arcangeli 116371e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 1164309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); 11651f25fe20SKirill A. Shutemov /* 11661f25fe20SKirill A. Shutemov * We can only reuse the page if nobody else maps the huge page or it's 11671f25fe20SKirill A. Shutemov * part. We can do it by checking page_mapcount() on each sub-page, but 11681f25fe20SKirill A. Shutemov * it's expensive. 11691f25fe20SKirill A. Shutemov * The cheaper way is to check page_count() to be equal 1: every 11701f25fe20SKirill A. Shutemov * mapcount takes page reference reference, so this way we can 11711f25fe20SKirill A. Shutemov * guarantee, that the PMD is the only mapping. 11721f25fe20SKirill A. Shutemov * This can give false negative if somebody pinned the page, but that's 11731f25fe20SKirill A. Shutemov * fine. 11741f25fe20SKirill A. Shutemov */ 11751f25fe20SKirill A. Shutemov if (page_mapcount(page) == 1 && page_count(page) == 1) { 117671e3aac0SAndrea Arcangeli pmd_t entry; 117771e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 117871e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 117971e3aac0SAndrea Arcangeli if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) 1180b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 118171e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 118271e3aac0SAndrea Arcangeli goto out_unlock; 118371e3aac0SAndrea Arcangeli } 1184ddc58f27SKirill A. Shutemov get_page(page); 1185c4088ebdSKirill A. Shutemov spin_unlock(ptl); 118693b4796dSKirill A. Shutemov alloc: 118771e3aac0SAndrea Arcangeli if (transparent_hugepage_enabled(vma) && 1188077fcf11SAneesh Kumar K.V !transparent_hugepage_debug_cow()) { 11893b363692SMichal Hocko huge_gfp = alloc_hugepage_gfpmask(transparent_hugepage_defrag(vma), 0); 11903b363692SMichal Hocko new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); 1191077fcf11SAneesh Kumar K.V } else 119271e3aac0SAndrea Arcangeli new_page = NULL; 119371e3aac0SAndrea Arcangeli 119471e3aac0SAndrea Arcangeli if (unlikely(!new_page)) { 1195eecc1e42SHugh Dickins if (!page) { 119678ddc534SKirill A. Shutemov split_huge_pmd(vma, pmd, address); 1197e9b71ca9SKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 119893b4796dSKirill A. Shutemov } else { 119971e3aac0SAndrea Arcangeli ret = do_huge_pmd_wp_page_fallback(mm, vma, address, 120071e3aac0SAndrea Arcangeli pmd, orig_pmd, page, haddr); 12019845cbbdSKirill A. Shutemov if (ret & VM_FAULT_OOM) { 120278ddc534SKirill A. Shutemov split_huge_pmd(vma, pmd, address); 12039845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 12049845cbbdSKirill A. Shutemov } 1205ddc58f27SKirill A. Shutemov put_page(page); 120693b4796dSKirill A. Shutemov } 120717766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 120871e3aac0SAndrea Arcangeli goto out; 120971e3aac0SAndrea Arcangeli } 121071e3aac0SAndrea Arcangeli 1211f627c2f5SKirill A. Shutemov if (unlikely(mem_cgroup_try_charge(new_page, mm, huge_gfp, &memcg, 1212f627c2f5SKirill A. Shutemov true))) { 1213b9bbfbe3SAndrea Arcangeli put_page(new_page); 121493b4796dSKirill A. Shutemov if (page) { 121578ddc534SKirill A. Shutemov split_huge_pmd(vma, pmd, address); 1216ddc58f27SKirill A. Shutemov put_page(page); 12179845cbbdSKirill A. Shutemov } else 121878ddc534SKirill A. Shutemov split_huge_pmd(vma, pmd, address); 12199845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 122017766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 1221b9bbfbe3SAndrea Arcangeli goto out; 1222b9bbfbe3SAndrea Arcangeli } 1223b9bbfbe3SAndrea Arcangeli 122417766ddeSDavid Rientjes count_vm_event(THP_FAULT_ALLOC); 122517766ddeSDavid Rientjes 1226eecc1e42SHugh Dickins if (!page) 122793b4796dSKirill A. Shutemov clear_huge_page(new_page, haddr, HPAGE_PMD_NR); 122893b4796dSKirill A. Shutemov else 122971e3aac0SAndrea Arcangeli copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); 123071e3aac0SAndrea Arcangeli __SetPageUptodate(new_page); 123171e3aac0SAndrea Arcangeli 12322ec74c3eSSagi Grimberg mmun_start = haddr; 12332ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 12342ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 12352ec74c3eSSagi Grimberg 1236c4088ebdSKirill A. Shutemov spin_lock(ptl); 123793b4796dSKirill A. Shutemov if (page) 1238ddc58f27SKirill A. Shutemov put_page(page); 1239b9bbfbe3SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) { 1240c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1241f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(new_page, memcg, true); 124271e3aac0SAndrea Arcangeli put_page(new_page); 12432ec74c3eSSagi Grimberg goto out_mn; 1244b9bbfbe3SAndrea Arcangeli } else { 124571e3aac0SAndrea Arcangeli pmd_t entry; 12463122359aSKirill A. Shutemov entry = mk_huge_pmd(new_page, vma->vm_page_prot); 12473122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 12488809aa2dSAneesh Kumar K.V pmdp_huge_clear_flush_notify(vma, haddr, pmd); 1249d281ee61SKirill A. Shutemov page_add_new_anon_rmap(new_page, vma, haddr, true); 1250f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(new_page, memcg, false, true); 125100501b53SJohannes Weiner lru_cache_add_active_or_unevictable(new_page, vma); 125271e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 1253b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 1254eecc1e42SHugh Dickins if (!page) { 125593b4796dSKirill A. Shutemov add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 125697ae1749SKirill A. Shutemov put_huge_zero_page(); 125797ae1749SKirill A. Shutemov } else { 1258309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1259d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 126071e3aac0SAndrea Arcangeli put_page(page); 126193b4796dSKirill A. Shutemov } 126271e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 126371e3aac0SAndrea Arcangeli } 1264c4088ebdSKirill A. Shutemov spin_unlock(ptl); 12652ec74c3eSSagi Grimberg out_mn: 12662ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 12672ec74c3eSSagi Grimberg out: 12682ec74c3eSSagi Grimberg return ret; 126971e3aac0SAndrea Arcangeli out_unlock: 1270c4088ebdSKirill A. Shutemov spin_unlock(ptl); 127171e3aac0SAndrea Arcangeli return ret; 127271e3aac0SAndrea Arcangeli } 127371e3aac0SAndrea Arcangeli 1274b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 127571e3aac0SAndrea Arcangeli unsigned long addr, 127671e3aac0SAndrea Arcangeli pmd_t *pmd, 127771e3aac0SAndrea Arcangeli unsigned int flags) 127871e3aac0SAndrea Arcangeli { 1279b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 128071e3aac0SAndrea Arcangeli struct page *page = NULL; 128171e3aac0SAndrea Arcangeli 1282c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 128371e3aac0SAndrea Arcangeli 128471e3aac0SAndrea Arcangeli if (flags & FOLL_WRITE && !pmd_write(*pmd)) 128571e3aac0SAndrea Arcangeli goto out; 128671e3aac0SAndrea Arcangeli 128785facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 128885facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 128985facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 129085facf25SKirill A. Shutemov 12912b4847e7SMel Gorman /* Full NUMA hinting faults to serialise migration in fault paths */ 12928a0516edSMel Gorman if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) 12932b4847e7SMel Gorman goto out; 12942b4847e7SMel Gorman 129571e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 1296309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 129771e3aac0SAndrea Arcangeli if (flags & FOLL_TOUCH) { 129871e3aac0SAndrea Arcangeli pmd_t _pmd; 129971e3aac0SAndrea Arcangeli /* 130071e3aac0SAndrea Arcangeli * We should set the dirty bit only for FOLL_WRITE but 130171e3aac0SAndrea Arcangeli * for now the dirty bit in the pmd is meaningless. 130271e3aac0SAndrea Arcangeli * And if the dirty bit will become meaningful and 130371e3aac0SAndrea Arcangeli * we'll only set it with FOLL_WRITE, an atomic 130471e3aac0SAndrea Arcangeli * set_bit will be required on the pmd to set the 130571e3aac0SAndrea Arcangeli * young bit, instead of the current set_pmd_at. 130671e3aac0SAndrea Arcangeli */ 130771e3aac0SAndrea Arcangeli _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); 13088663890aSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 13098663890aSAneesh Kumar K.V pmd, _pmd, 1)) 13108663890aSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 131171e3aac0SAndrea Arcangeli } 1312de60f5f1SEric B Munson if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { 1313b676b293SDavid Rientjes if (page->mapping && trylock_page(page)) { 1314b676b293SDavid Rientjes lru_add_drain(); 1315b676b293SDavid Rientjes if (page->mapping) 1316b676b293SDavid Rientjes mlock_vma_page(page); 1317b676b293SDavid Rientjes unlock_page(page); 1318b676b293SDavid Rientjes } 1319b676b293SDavid Rientjes } 132071e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1321309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 132271e3aac0SAndrea Arcangeli if (flags & FOLL_GET) 1323ddc58f27SKirill A. Shutemov get_page(page); 132471e3aac0SAndrea Arcangeli 132571e3aac0SAndrea Arcangeli out: 132671e3aac0SAndrea Arcangeli return page; 132771e3aac0SAndrea Arcangeli } 132871e3aac0SAndrea Arcangeli 1329d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 13304daae3b4SMel Gorman int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, 13314daae3b4SMel Gorman unsigned long addr, pmd_t pmd, pmd_t *pmdp) 1332d10e63f2SMel Gorman { 1333c4088ebdSKirill A. Shutemov spinlock_t *ptl; 1334b8916634SMel Gorman struct anon_vma *anon_vma = NULL; 1335b32967ffSMel Gorman struct page *page; 1336d10e63f2SMel Gorman unsigned long haddr = addr & HPAGE_PMD_MASK; 13378191acbdSMel Gorman int page_nid = -1, this_nid = numa_node_id(); 133890572890SPeter Zijlstra int target_nid, last_cpupid = -1; 13398191acbdSMel Gorman bool page_locked; 13408191acbdSMel Gorman bool migrated = false; 1341b191f9b1SMel Gorman bool was_writable; 13426688cc05SPeter Zijlstra int flags = 0; 1343d10e63f2SMel Gorman 1344c0e7cad9SMel Gorman /* A PROT_NONE fault should not end up here */ 1345c0e7cad9SMel Gorman BUG_ON(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))); 1346c0e7cad9SMel Gorman 1347c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmdp); 1348d10e63f2SMel Gorman if (unlikely(!pmd_same(pmd, *pmdp))) 1349d10e63f2SMel Gorman goto out_unlock; 1350d10e63f2SMel Gorman 1351de466bd6SMel Gorman /* 1352de466bd6SMel Gorman * If there are potential migrations, wait for completion and retry 1353de466bd6SMel Gorman * without disrupting NUMA hinting information. Do not relock and 1354de466bd6SMel Gorman * check_same as the page may no longer be mapped. 1355de466bd6SMel Gorman */ 1356de466bd6SMel Gorman if (unlikely(pmd_trans_migrating(*pmdp))) { 13575d833062SMel Gorman page = pmd_page(*pmdp); 1358de466bd6SMel Gorman spin_unlock(ptl); 13595d833062SMel Gorman wait_on_page_locked(page); 1360de466bd6SMel Gorman goto out; 1361de466bd6SMel Gorman } 1362de466bd6SMel Gorman 1363d10e63f2SMel Gorman page = pmd_page(pmd); 1364a1a46184SMel Gorman BUG_ON(is_huge_zero_page(page)); 13658191acbdSMel Gorman page_nid = page_to_nid(page); 136690572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 136703c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 136804bb2f94SRik van Riel if (page_nid == this_nid) { 136903c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 137004bb2f94SRik van Riel flags |= TNF_FAULT_LOCAL; 137104bb2f94SRik van Riel } 13724daae3b4SMel Gorman 1373bea66fbdSMel Gorman /* See similar comment in do_numa_page for explanation */ 1374bea66fbdSMel Gorman if (!(vma->vm_flags & VM_WRITE)) 13756688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 13766688cc05SPeter Zijlstra 13776688cc05SPeter Zijlstra /* 1378ff9042b1SMel Gorman * Acquire the page lock to serialise THP migrations but avoid dropping 1379ff9042b1SMel Gorman * page_table_lock if at all possible 1380ff9042b1SMel Gorman */ 1381b8916634SMel Gorman page_locked = trylock_page(page); 1382b8916634SMel Gorman target_nid = mpol_misplaced(page, vma, haddr); 1383b8916634SMel Gorman if (target_nid == -1) { 1384b8916634SMel Gorman /* If the page was locked, there are no parallel migrations */ 1385a54a407fSMel Gorman if (page_locked) 1386b8916634SMel Gorman goto clear_pmdnuma; 13872b4847e7SMel Gorman } 1388cbee9f88SPeter Zijlstra 1389de466bd6SMel Gorman /* Migration could have started since the pmd_trans_migrating check */ 13902b4847e7SMel Gorman if (!page_locked) { 1391c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1392b8916634SMel Gorman wait_on_page_locked(page); 1393a54a407fSMel Gorman page_nid = -1; 1394b8916634SMel Gorman goto out; 1395b8916634SMel Gorman } 1396b8916634SMel Gorman 13972b4847e7SMel Gorman /* 13982b4847e7SMel Gorman * Page is misplaced. Page lock serialises migrations. Acquire anon_vma 13992b4847e7SMel Gorman * to serialises splits 14002b4847e7SMel Gorman */ 1401b8916634SMel Gorman get_page(page); 1402c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1403b8916634SMel Gorman anon_vma = page_lock_anon_vma_read(page); 1404b32967ffSMel Gorman 1405c69307d5SPeter Zijlstra /* Confirm the PMD did not change while page_table_lock was released */ 1406c4088ebdSKirill A. Shutemov spin_lock(ptl); 1407b32967ffSMel Gorman if (unlikely(!pmd_same(pmd, *pmdp))) { 1408b32967ffSMel Gorman unlock_page(page); 1409b32967ffSMel Gorman put_page(page); 1410a54a407fSMel Gorman page_nid = -1; 1411b32967ffSMel Gorman goto out_unlock; 1412b32967ffSMel Gorman } 1413ff9042b1SMel Gorman 1414c3a489caSMel Gorman /* Bail if we fail to protect against THP splits for any reason */ 1415c3a489caSMel Gorman if (unlikely(!anon_vma)) { 1416c3a489caSMel Gorman put_page(page); 1417c3a489caSMel Gorman page_nid = -1; 1418c3a489caSMel Gorman goto clear_pmdnuma; 1419c3a489caSMel Gorman } 1420c3a489caSMel Gorman 1421a54a407fSMel Gorman /* 1422a54a407fSMel Gorman * Migrate the THP to the requested node, returns with page unlocked 14238a0516edSMel Gorman * and access rights restored. 1424a54a407fSMel Gorman */ 1425c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1426b32967ffSMel Gorman migrated = migrate_misplaced_transhuge_page(mm, vma, 1427340ef390SHugh Dickins pmdp, pmd, addr, page, target_nid); 14286688cc05SPeter Zijlstra if (migrated) { 14296688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 14308191acbdSMel Gorman page_nid = target_nid; 1431074c2381SMel Gorman } else 1432074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1433b32967ffSMel Gorman 14348191acbdSMel Gorman goto out; 14354daae3b4SMel Gorman clear_pmdnuma: 1436a54a407fSMel Gorman BUG_ON(!PageLocked(page)); 1437b191f9b1SMel Gorman was_writable = pmd_write(pmd); 14384d942466SMel Gorman pmd = pmd_modify(pmd, vma->vm_page_prot); 1439b7b04004SMel Gorman pmd = pmd_mkyoung(pmd); 1440b191f9b1SMel Gorman if (was_writable) 1441b191f9b1SMel Gorman pmd = pmd_mkwrite(pmd); 1442d10e63f2SMel Gorman set_pmd_at(mm, haddr, pmdp, pmd); 1443d10e63f2SMel Gorman update_mmu_cache_pmd(vma, addr, pmdp); 1444a54a407fSMel Gorman unlock_page(page); 1445d10e63f2SMel Gorman out_unlock: 1446c4088ebdSKirill A. Shutemov spin_unlock(ptl); 1447b8916634SMel Gorman 1448b8916634SMel Gorman out: 1449b8916634SMel Gorman if (anon_vma) 1450b8916634SMel Gorman page_unlock_anon_vma_read(anon_vma); 1451b8916634SMel Gorman 14528191acbdSMel Gorman if (page_nid != -1) 14536688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags); 14548191acbdSMel Gorman 1455d10e63f2SMel Gorman return 0; 1456d10e63f2SMel Gorman } 1457d10e63f2SMel Gorman 145871e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1459f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 146071e3aac0SAndrea Arcangeli { 1461f5c8ad47SDavid Miller pmd_t orig_pmd; 1462da146769SKirill A. Shutemov spinlock_t *ptl; 1463da146769SKirill A. Shutemov 1464*4b471e88SKirill A. Shutemov if (!__pmd_trans_huge_lock(pmd, vma, &ptl)) 1465da146769SKirill A. Shutemov return 0; 1466a6bf2bb0SAneesh Kumar K.V /* 1467a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 14688809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1469a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1470a6bf2bb0SAneesh Kumar K.V * operations. 1471a6bf2bb0SAneesh Kumar K.V */ 14728809aa2dSAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, 1473fcbe08d6SMartin Schwidefsky tlb->fullmm); 1474f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 14754897c765SMatthew Wilcox if (vma_is_dax(vma)) { 14764897c765SMatthew Wilcox spin_unlock(ptl); 1477da146769SKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 1478da146769SKirill A. Shutemov put_huge_zero_page(); 1479da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1480da146769SKirill A. Shutemov pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd)); 1481e1f56c89SKirill A. Shutemov atomic_long_dec(&tlb->mm->nr_ptes); 1482bf929152SKirill A. Shutemov spin_unlock(ptl); 148397ae1749SKirill A. Shutemov put_huge_zero_page(); 1484479f0abbSKirill A. Shutemov } else { 14854897c765SMatthew Wilcox struct page *page = pmd_page(orig_pmd); 1486d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 1487309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 148871e3aac0SAndrea Arcangeli add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1489309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1490da146769SKirill A. Shutemov pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd)); 1491e1f56c89SKirill A. Shutemov atomic_long_dec(&tlb->mm->nr_ptes); 1492bf929152SKirill A. Shutemov spin_unlock(ptl); 149371e3aac0SAndrea Arcangeli tlb_remove_page(tlb, page); 1494479f0abbSKirill A. Shutemov } 1495da146769SKirill A. Shutemov return 1; 149671e3aac0SAndrea Arcangeli } 149771e3aac0SAndrea Arcangeli 1498*4b471e88SKirill A. Shutemov bool move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, 149937a1c49aSAndrea Arcangeli unsigned long old_addr, 150037a1c49aSAndrea Arcangeli unsigned long new_addr, unsigned long old_end, 150137a1c49aSAndrea Arcangeli pmd_t *old_pmd, pmd_t *new_pmd) 150237a1c49aSAndrea Arcangeli { 1503bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 150437a1c49aSAndrea Arcangeli pmd_t pmd; 150537a1c49aSAndrea Arcangeli 150637a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 150737a1c49aSAndrea Arcangeli 150837a1c49aSAndrea Arcangeli if ((old_addr & ~HPAGE_PMD_MASK) || 150937a1c49aSAndrea Arcangeli (new_addr & ~HPAGE_PMD_MASK) || 151037a1c49aSAndrea Arcangeli old_end - old_addr < HPAGE_PMD_SIZE || 151137a1c49aSAndrea Arcangeli (new_vma->vm_flags & VM_NOHUGEPAGE)) 1512*4b471e88SKirill A. Shutemov return false; 151337a1c49aSAndrea Arcangeli 151437a1c49aSAndrea Arcangeli /* 151537a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 151637a1c49aSAndrea Arcangeli * should have release it. 151737a1c49aSAndrea Arcangeli */ 151837a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 151937a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 1520*4b471e88SKirill A. Shutemov return false; 152137a1c49aSAndrea Arcangeli } 152237a1c49aSAndrea Arcangeli 1523bf929152SKirill A. Shutemov /* 1524bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1525bf929152SKirill A. Shutemov * ptlocks because exclusive mmap_sem prevents deadlock. 1526bf929152SKirill A. Shutemov */ 1527*4b471e88SKirill A. Shutemov if (__pmd_trans_huge_lock(old_pmd, vma, &old_ptl)) { 1528bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1529bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1530bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 15318809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 153237a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 15333592806cSKirill A. Shutemov 1534b3084f4dSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl)) { 1535b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 15363592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 15373592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 15383592806cSKirill A. Shutemov } 1539b3084f4dSAneesh Kumar K.V set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); 1540b3084f4dSAneesh Kumar K.V if (new_ptl != old_ptl) 1541b3084f4dSAneesh Kumar K.V spin_unlock(new_ptl); 1542bf929152SKirill A. Shutemov spin_unlock(old_ptl); 1543*4b471e88SKirill A. Shutemov return true; 154437a1c49aSAndrea Arcangeli } 1545*4b471e88SKirill A. Shutemov return false; 154637a1c49aSAndrea Arcangeli } 154737a1c49aSAndrea Arcangeli 1548f123d74aSMel Gorman /* 1549f123d74aSMel Gorman * Returns 1550f123d74aSMel Gorman * - 0 if PMD could not be locked 1551f123d74aSMel Gorman * - 1 if PMD was locked but protections unchange and TLB flush unnecessary 1552f123d74aSMel Gorman * - HPAGE_PMD_NR is protections changed and TLB flush necessary 1553f123d74aSMel Gorman */ 1554cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 1555e944fd67SMel Gorman unsigned long addr, pgprot_t newprot, int prot_numa) 1556cd7548abSJohannes Weiner { 1557cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1558bf929152SKirill A. Shutemov spinlock_t *ptl; 1559cd7548abSJohannes Weiner int ret = 0; 1560cd7548abSJohannes Weiner 1561*4b471e88SKirill A. Shutemov if (__pmd_trans_huge_lock(pmd, vma, &ptl)) { 1562cd7548abSJohannes Weiner pmd_t entry; 1563b191f9b1SMel Gorman bool preserve_write = prot_numa && pmd_write(*pmd); 1564ba68bc01SMel Gorman ret = 1; 1565e944fd67SMel Gorman 1566e944fd67SMel Gorman /* 1567e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1568e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1569e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1570e944fd67SMel Gorman */ 1571e944fd67SMel Gorman if (prot_numa && is_huge_zero_pmd(*pmd)) { 1572e944fd67SMel Gorman spin_unlock(ptl); 1573ba68bc01SMel Gorman return ret; 1574e944fd67SMel Gorman } 1575e944fd67SMel Gorman 157610c1045fSMel Gorman if (!prot_numa || !pmd_protnone(*pmd)) { 15778809aa2dSAneesh Kumar K.V entry = pmdp_huge_get_and_clear_notify(mm, addr, pmd); 1578cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 1579b191f9b1SMel Gorman if (preserve_write) 1580b191f9b1SMel Gorman entry = pmd_mkwrite(entry); 1581f123d74aSMel Gorman ret = HPAGE_PMD_NR; 158256eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 1583b191f9b1SMel Gorman BUG_ON(!preserve_write && pmd_write(entry)); 158410c1045fSMel Gorman } 1585bf929152SKirill A. Shutemov spin_unlock(ptl); 1586cd7548abSJohannes Weiner } 1587cd7548abSJohannes Weiner 1588cd7548abSJohannes Weiner return ret; 1589cd7548abSJohannes Weiner } 1590cd7548abSJohannes Weiner 1591025c5b24SNaoya Horiguchi /* 1592*4b471e88SKirill A. Shutemov * Returns true if a given pmd maps a thp, false otherwise. 1593025c5b24SNaoya Horiguchi * 1594*4b471e88SKirill A. Shutemov * Note that if it returns true, this routine returns without unlocking page 1595*4b471e88SKirill A. Shutemov * table lock. So callers must unlock it. 1596025c5b24SNaoya Horiguchi */ 1597*4b471e88SKirill A. Shutemov bool __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, 1598bf929152SKirill A. Shutemov spinlock_t **ptl) 1599025c5b24SNaoya Horiguchi { 1600bf929152SKirill A. Shutemov *ptl = pmd_lock(vma->vm_mm, pmd); 1601*4b471e88SKirill A. Shutemov if (likely(pmd_trans_huge(*pmd))) 1602*4b471e88SKirill A. Shutemov return true; 1603bf929152SKirill A. Shutemov spin_unlock(*ptl); 1604*4b471e88SKirill A. Shutemov return false; 1605025c5b24SNaoya Horiguchi } 1606025c5b24SNaoya Horiguchi 1607117b0791SKirill A. Shutemov /* 1608117b0791SKirill A. Shutemov * This function returns whether a given @page is mapped onto the @address 1609117b0791SKirill A. Shutemov * in the virtual space of @mm. 1610117b0791SKirill A. Shutemov * 1611117b0791SKirill A. Shutemov * When it's true, this function returns *pmd with holding the page table lock 1612117b0791SKirill A. Shutemov * and passing it back to the caller via @ptl. 1613117b0791SKirill A. Shutemov * If it's false, returns NULL without holding the page table lock. 1614117b0791SKirill A. Shutemov */ 161571e3aac0SAndrea Arcangeli pmd_t *page_check_address_pmd(struct page *page, 161671e3aac0SAndrea Arcangeli struct mm_struct *mm, 161771e3aac0SAndrea Arcangeli unsigned long address, 1618117b0791SKirill A. Shutemov spinlock_t **ptl) 161971e3aac0SAndrea Arcangeli { 1620b5a8cad3SKirill A. Shutemov pgd_t *pgd; 1621b5a8cad3SKirill A. Shutemov pud_t *pud; 1622117b0791SKirill A. Shutemov pmd_t *pmd; 162371e3aac0SAndrea Arcangeli 162471e3aac0SAndrea Arcangeli if (address & ~HPAGE_PMD_MASK) 1625117b0791SKirill A. Shutemov return NULL; 162671e3aac0SAndrea Arcangeli 1627b5a8cad3SKirill A. Shutemov pgd = pgd_offset(mm, address); 1628b5a8cad3SKirill A. Shutemov if (!pgd_present(*pgd)) 1629117b0791SKirill A. Shutemov return NULL; 1630b5a8cad3SKirill A. Shutemov pud = pud_offset(pgd, address); 1631b5a8cad3SKirill A. Shutemov if (!pud_present(*pud)) 1632b5a8cad3SKirill A. Shutemov return NULL; 1633b5a8cad3SKirill A. Shutemov pmd = pmd_offset(pud, address); 1634b5a8cad3SKirill A. Shutemov 1635117b0791SKirill A. Shutemov *ptl = pmd_lock(mm, pmd); 1636b5a8cad3SKirill A. Shutemov if (!pmd_present(*pmd)) 1637117b0791SKirill A. Shutemov goto unlock; 163871e3aac0SAndrea Arcangeli if (pmd_page(*pmd) != page) 1639117b0791SKirill A. Shutemov goto unlock; 1640*4b471e88SKirill A. Shutemov if (pmd_trans_huge(*pmd)) 1641117b0791SKirill A. Shutemov return pmd; 1642117b0791SKirill A. Shutemov unlock: 1643117b0791SKirill A. Shutemov spin_unlock(*ptl); 1644117b0791SKirill A. Shutemov return NULL; 164571e3aac0SAndrea Arcangeli } 164671e3aac0SAndrea Arcangeli 16479050d7ebSVlastimil Babka #define VM_NO_THP (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE) 164878f11a25SAndrea Arcangeli 164960ab3244SAndrea Arcangeli int hugepage_madvise(struct vm_area_struct *vma, 165060ab3244SAndrea Arcangeli unsigned long *vm_flags, int advice) 16510af4e98bSAndrea Arcangeli { 1652a664b2d8SAndrea Arcangeli switch (advice) { 1653a664b2d8SAndrea Arcangeli case MADV_HUGEPAGE: 16541e1836e8SAlex Thorlton #ifdef CONFIG_S390 16551e1836e8SAlex Thorlton /* 16561e1836e8SAlex Thorlton * qemu blindly sets MADV_HUGEPAGE on all allocations, but s390 16571e1836e8SAlex Thorlton * can't handle this properly after s390_enable_sie, so we simply 16581e1836e8SAlex Thorlton * ignore the madvise to prevent qemu from causing a SIGSEGV. 16591e1836e8SAlex Thorlton */ 16601e1836e8SAlex Thorlton if (mm_has_pgste(vma->vm_mm)) 16611e1836e8SAlex Thorlton return 0; 16621e1836e8SAlex Thorlton #endif 16630af4e98bSAndrea Arcangeli /* 16640af4e98bSAndrea Arcangeli * Be somewhat over-protective like KSM for now! 16650af4e98bSAndrea Arcangeli */ 16661a763615SJason J. Herne if (*vm_flags & VM_NO_THP) 16670af4e98bSAndrea Arcangeli return -EINVAL; 1668a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_NOHUGEPAGE; 16690af4e98bSAndrea Arcangeli *vm_flags |= VM_HUGEPAGE; 167060ab3244SAndrea Arcangeli /* 167160ab3244SAndrea Arcangeli * If the vma become good for khugepaged to scan, 167260ab3244SAndrea Arcangeli * register it here without waiting a page fault that 167360ab3244SAndrea Arcangeli * may not happen any time soon. 167460ab3244SAndrea Arcangeli */ 16756d50e60cSDavid Rientjes if (unlikely(khugepaged_enter_vma_merge(vma, *vm_flags))) 167660ab3244SAndrea Arcangeli return -ENOMEM; 1677a664b2d8SAndrea Arcangeli break; 1678a664b2d8SAndrea Arcangeli case MADV_NOHUGEPAGE: 1679a664b2d8SAndrea Arcangeli /* 1680a664b2d8SAndrea Arcangeli * Be somewhat over-protective like KSM for now! 1681a664b2d8SAndrea Arcangeli */ 16821a763615SJason J. Herne if (*vm_flags & VM_NO_THP) 1683a664b2d8SAndrea Arcangeli return -EINVAL; 1684a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_HUGEPAGE; 1685a664b2d8SAndrea Arcangeli *vm_flags |= VM_NOHUGEPAGE; 168660ab3244SAndrea Arcangeli /* 168760ab3244SAndrea Arcangeli * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning 168860ab3244SAndrea Arcangeli * this vma even if we leave the mm registered in khugepaged if 168960ab3244SAndrea Arcangeli * it got registered before VM_NOHUGEPAGE was set. 169060ab3244SAndrea Arcangeli */ 1691a664b2d8SAndrea Arcangeli break; 1692a664b2d8SAndrea Arcangeli } 16930af4e98bSAndrea Arcangeli 16940af4e98bSAndrea Arcangeli return 0; 16950af4e98bSAndrea Arcangeli } 16960af4e98bSAndrea Arcangeli 1697ba76149fSAndrea Arcangeli static int __init khugepaged_slab_init(void) 1698ba76149fSAndrea Arcangeli { 1699ba76149fSAndrea Arcangeli mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", 1700ba76149fSAndrea Arcangeli sizeof(struct mm_slot), 1701ba76149fSAndrea Arcangeli __alignof__(struct mm_slot), 0, NULL); 1702ba76149fSAndrea Arcangeli if (!mm_slot_cache) 1703ba76149fSAndrea Arcangeli return -ENOMEM; 1704ba76149fSAndrea Arcangeli 1705ba76149fSAndrea Arcangeli return 0; 1706ba76149fSAndrea Arcangeli } 1707ba76149fSAndrea Arcangeli 170865ebb64fSKirill A. Shutemov static void __init khugepaged_slab_exit(void) 170965ebb64fSKirill A. Shutemov { 171065ebb64fSKirill A. Shutemov kmem_cache_destroy(mm_slot_cache); 171165ebb64fSKirill A. Shutemov } 171265ebb64fSKirill A. Shutemov 1713ba76149fSAndrea Arcangeli static inline struct mm_slot *alloc_mm_slot(void) 1714ba76149fSAndrea Arcangeli { 1715ba76149fSAndrea Arcangeli if (!mm_slot_cache) /* initialization failed */ 1716ba76149fSAndrea Arcangeli return NULL; 1717ba76149fSAndrea Arcangeli return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); 1718ba76149fSAndrea Arcangeli } 1719ba76149fSAndrea Arcangeli 1720ba76149fSAndrea Arcangeli static inline void free_mm_slot(struct mm_slot *mm_slot) 1721ba76149fSAndrea Arcangeli { 1722ba76149fSAndrea Arcangeli kmem_cache_free(mm_slot_cache, mm_slot); 1723ba76149fSAndrea Arcangeli } 1724ba76149fSAndrea Arcangeli 1725ba76149fSAndrea Arcangeli static struct mm_slot *get_mm_slot(struct mm_struct *mm) 1726ba76149fSAndrea Arcangeli { 1727ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1728ba76149fSAndrea Arcangeli 1729b67bfe0dSSasha Levin hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm) 1730ba76149fSAndrea Arcangeli if (mm == mm_slot->mm) 1731ba76149fSAndrea Arcangeli return mm_slot; 173243b5fbbdSSasha Levin 1733ba76149fSAndrea Arcangeli return NULL; 1734ba76149fSAndrea Arcangeli } 1735ba76149fSAndrea Arcangeli 1736ba76149fSAndrea Arcangeli static void insert_to_mm_slots_hash(struct mm_struct *mm, 1737ba76149fSAndrea Arcangeli struct mm_slot *mm_slot) 1738ba76149fSAndrea Arcangeli { 1739ba76149fSAndrea Arcangeli mm_slot->mm = mm; 174043b5fbbdSSasha Levin hash_add(mm_slots_hash, &mm_slot->hash, (long)mm); 1741ba76149fSAndrea Arcangeli } 1742ba76149fSAndrea Arcangeli 1743ba76149fSAndrea Arcangeli static inline int khugepaged_test_exit(struct mm_struct *mm) 1744ba76149fSAndrea Arcangeli { 1745ba76149fSAndrea Arcangeli return atomic_read(&mm->mm_users) == 0; 1746ba76149fSAndrea Arcangeli } 1747ba76149fSAndrea Arcangeli 1748ba76149fSAndrea Arcangeli int __khugepaged_enter(struct mm_struct *mm) 1749ba76149fSAndrea Arcangeli { 1750ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1751ba76149fSAndrea Arcangeli int wakeup; 1752ba76149fSAndrea Arcangeli 1753ba76149fSAndrea Arcangeli mm_slot = alloc_mm_slot(); 1754ba76149fSAndrea Arcangeli if (!mm_slot) 1755ba76149fSAndrea Arcangeli return -ENOMEM; 1756ba76149fSAndrea Arcangeli 1757ba76149fSAndrea Arcangeli /* __khugepaged_exit() must not run from under us */ 175896dad67fSSasha Levin VM_BUG_ON_MM(khugepaged_test_exit(mm), mm); 1759ba76149fSAndrea Arcangeli if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { 1760ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 1761ba76149fSAndrea Arcangeli return 0; 1762ba76149fSAndrea Arcangeli } 1763ba76149fSAndrea Arcangeli 1764ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 1765ba76149fSAndrea Arcangeli insert_to_mm_slots_hash(mm, mm_slot); 1766ba76149fSAndrea Arcangeli /* 1767ba76149fSAndrea Arcangeli * Insert just behind the scanning cursor, to let the area settle 1768ba76149fSAndrea Arcangeli * down a little. 1769ba76149fSAndrea Arcangeli */ 1770ba76149fSAndrea Arcangeli wakeup = list_empty(&khugepaged_scan.mm_head); 1771ba76149fSAndrea Arcangeli list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); 1772ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 1773ba76149fSAndrea Arcangeli 1774ba76149fSAndrea Arcangeli atomic_inc(&mm->mm_count); 1775ba76149fSAndrea Arcangeli if (wakeup) 1776ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 1777ba76149fSAndrea Arcangeli 1778ba76149fSAndrea Arcangeli return 0; 1779ba76149fSAndrea Arcangeli } 1780ba76149fSAndrea Arcangeli 17816d50e60cSDavid Rientjes int khugepaged_enter_vma_merge(struct vm_area_struct *vma, 17826d50e60cSDavid Rientjes unsigned long vm_flags) 1783ba76149fSAndrea Arcangeli { 1784ba76149fSAndrea Arcangeli unsigned long hstart, hend; 1785ba76149fSAndrea Arcangeli if (!vma->anon_vma) 1786ba76149fSAndrea Arcangeli /* 1787ba76149fSAndrea Arcangeli * Not yet faulted in so we will register later in the 1788ba76149fSAndrea Arcangeli * page fault if needed. 1789ba76149fSAndrea Arcangeli */ 1790ba76149fSAndrea Arcangeli return 0; 179178f11a25SAndrea Arcangeli if (vma->vm_ops) 1792ba76149fSAndrea Arcangeli /* khugepaged not yet working on file or special mappings */ 1793ba76149fSAndrea Arcangeli return 0; 17946d50e60cSDavid Rientjes VM_BUG_ON_VMA(vm_flags & VM_NO_THP, vma); 1795ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 1796ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 1797ba76149fSAndrea Arcangeli if (hstart < hend) 17986d50e60cSDavid Rientjes return khugepaged_enter(vma, vm_flags); 1799ba76149fSAndrea Arcangeli return 0; 1800ba76149fSAndrea Arcangeli } 1801ba76149fSAndrea Arcangeli 1802ba76149fSAndrea Arcangeli void __khugepaged_exit(struct mm_struct *mm) 1803ba76149fSAndrea Arcangeli { 1804ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1805ba76149fSAndrea Arcangeli int free = 0; 1806ba76149fSAndrea Arcangeli 1807ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 1808ba76149fSAndrea Arcangeli mm_slot = get_mm_slot(mm); 1809ba76149fSAndrea Arcangeli if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { 181043b5fbbdSSasha Levin hash_del(&mm_slot->hash); 1811ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 1812ba76149fSAndrea Arcangeli free = 1; 1813ba76149fSAndrea Arcangeli } 1814d788e80aSChris Wright spin_unlock(&khugepaged_mm_lock); 1815ba76149fSAndrea Arcangeli 1816ba76149fSAndrea Arcangeli if (free) { 1817ba76149fSAndrea Arcangeli clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 1818ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 1819ba76149fSAndrea Arcangeli mmdrop(mm); 1820ba76149fSAndrea Arcangeli } else if (mm_slot) { 1821ba76149fSAndrea Arcangeli /* 1822ba76149fSAndrea Arcangeli * This is required to serialize against 1823ba76149fSAndrea Arcangeli * khugepaged_test_exit() (which is guaranteed to run 1824ba76149fSAndrea Arcangeli * under mmap sem read mode). Stop here (after we 1825ba76149fSAndrea Arcangeli * return all pagetables will be destroyed) until 1826ba76149fSAndrea Arcangeli * khugepaged has finished working on the pagetables 1827ba76149fSAndrea Arcangeli * under the mmap_sem. 1828ba76149fSAndrea Arcangeli */ 1829ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 1830ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 1831d788e80aSChris Wright } 1832ba76149fSAndrea Arcangeli } 1833ba76149fSAndrea Arcangeli 1834ba76149fSAndrea Arcangeli static void release_pte_page(struct page *page) 1835ba76149fSAndrea Arcangeli { 1836ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 1837ba76149fSAndrea Arcangeli dec_zone_page_state(page, NR_ISOLATED_ANON + 0); 1838ba76149fSAndrea Arcangeli unlock_page(page); 1839ba76149fSAndrea Arcangeli putback_lru_page(page); 1840ba76149fSAndrea Arcangeli } 1841ba76149fSAndrea Arcangeli 1842ba76149fSAndrea Arcangeli static void release_pte_pages(pte_t *pte, pte_t *_pte) 1843ba76149fSAndrea Arcangeli { 1844ba76149fSAndrea Arcangeli while (--_pte >= pte) { 1845ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 1846ca0984caSEbru Akagunduz if (!pte_none(pteval) && !is_zero_pfn(pte_pfn(pteval))) 1847ba76149fSAndrea Arcangeli release_pte_page(pte_page(pteval)); 1848ba76149fSAndrea Arcangeli } 1849ba76149fSAndrea Arcangeli } 1850ba76149fSAndrea Arcangeli 1851ba76149fSAndrea Arcangeli static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 1852ba76149fSAndrea Arcangeli unsigned long address, 1853ba76149fSAndrea Arcangeli pte_t *pte) 1854ba76149fSAndrea Arcangeli { 18557d2eba05SEbru Akagunduz struct page *page = NULL; 1856ba76149fSAndrea Arcangeli pte_t *_pte; 18577d2eba05SEbru Akagunduz int none_or_zero = 0, result = 0; 185810359213SEbru Akagunduz bool referenced = false, writable = false; 18597d2eba05SEbru Akagunduz 1860ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; 1861ba76149fSAndrea Arcangeli _pte++, address += PAGE_SIZE) { 1862ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 186347aee4d8SMinchan Kim if (pte_none(pteval) || (pte_present(pteval) && 186447aee4d8SMinchan Kim is_zero_pfn(pte_pfn(pteval)))) { 1865c1294d05SAndrea Arcangeli if (!userfaultfd_armed(vma) && 18667d2eba05SEbru Akagunduz ++none_or_zero <= khugepaged_max_ptes_none) { 1867ba76149fSAndrea Arcangeli continue; 18687d2eba05SEbru Akagunduz } else { 18697d2eba05SEbru Akagunduz result = SCAN_EXCEED_NONE_PTE; 1870ba76149fSAndrea Arcangeli goto out; 1871ba76149fSAndrea Arcangeli } 18727d2eba05SEbru Akagunduz } 18737d2eba05SEbru Akagunduz if (!pte_present(pteval)) { 18747d2eba05SEbru Akagunduz result = SCAN_PTE_NON_PRESENT; 1875ba76149fSAndrea Arcangeli goto out; 18767d2eba05SEbru Akagunduz } 1877ba76149fSAndrea Arcangeli page = vm_normal_page(vma, address, pteval); 18787d2eba05SEbru Akagunduz if (unlikely(!page)) { 18797d2eba05SEbru Akagunduz result = SCAN_PAGE_NULL; 1880ba76149fSAndrea Arcangeli goto out; 18817d2eba05SEbru Akagunduz } 1882344aa35cSBob Liu 1883309381feSSasha Levin VM_BUG_ON_PAGE(PageCompound(page), page); 1884309381feSSasha Levin VM_BUG_ON_PAGE(!PageAnon(page), page); 1885309381feSSasha Levin VM_BUG_ON_PAGE(!PageSwapBacked(page), page); 1886ba76149fSAndrea Arcangeli 1887ba76149fSAndrea Arcangeli /* 1888ba76149fSAndrea Arcangeli * We can do it before isolate_lru_page because the 1889ba76149fSAndrea Arcangeli * page can't be freed from under us. NOTE: PG_lock 1890ba76149fSAndrea Arcangeli * is needed to serialize against split_huge_page 1891ba76149fSAndrea Arcangeli * when invoked from the VM. 1892ba76149fSAndrea Arcangeli */ 18937d2eba05SEbru Akagunduz if (!trylock_page(page)) { 18947d2eba05SEbru Akagunduz result = SCAN_PAGE_LOCK; 1895ba76149fSAndrea Arcangeli goto out; 18967d2eba05SEbru Akagunduz } 189710359213SEbru Akagunduz 189810359213SEbru Akagunduz /* 189910359213SEbru Akagunduz * cannot use mapcount: can't collapse if there's a gup pin. 190010359213SEbru Akagunduz * The page must only be referenced by the scanned process 190110359213SEbru Akagunduz * and page swap cache. 190210359213SEbru Akagunduz */ 190310359213SEbru Akagunduz if (page_count(page) != 1 + !!PageSwapCache(page)) { 190410359213SEbru Akagunduz unlock_page(page); 19057d2eba05SEbru Akagunduz result = SCAN_PAGE_COUNT; 190610359213SEbru Akagunduz goto out; 190710359213SEbru Akagunduz } 190810359213SEbru Akagunduz if (pte_write(pteval)) { 190910359213SEbru Akagunduz writable = true; 191010359213SEbru Akagunduz } else { 191110359213SEbru Akagunduz if (PageSwapCache(page) && !reuse_swap_page(page)) { 191210359213SEbru Akagunduz unlock_page(page); 19137d2eba05SEbru Akagunduz result = SCAN_SWAP_CACHE_PAGE; 191410359213SEbru Akagunduz goto out; 191510359213SEbru Akagunduz } 191610359213SEbru Akagunduz /* 191710359213SEbru Akagunduz * Page is not in the swap cache. It can be collapsed 191810359213SEbru Akagunduz * into a THP. 191910359213SEbru Akagunduz */ 192010359213SEbru Akagunduz } 192110359213SEbru Akagunduz 1922ba76149fSAndrea Arcangeli /* 1923ba76149fSAndrea Arcangeli * Isolate the page to avoid collapsing an hugepage 1924ba76149fSAndrea Arcangeli * currently in use by the VM. 1925ba76149fSAndrea Arcangeli */ 1926ba76149fSAndrea Arcangeli if (isolate_lru_page(page)) { 1927ba76149fSAndrea Arcangeli unlock_page(page); 19287d2eba05SEbru Akagunduz result = SCAN_DEL_PAGE_LRU; 1929ba76149fSAndrea Arcangeli goto out; 1930ba76149fSAndrea Arcangeli } 1931ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 1932ba76149fSAndrea Arcangeli inc_zone_page_state(page, NR_ISOLATED_ANON + 0); 1933309381feSSasha Levin VM_BUG_ON_PAGE(!PageLocked(page), page); 1934309381feSSasha Levin VM_BUG_ON_PAGE(PageLRU(page), page); 1935ba76149fSAndrea Arcangeli 1936ba76149fSAndrea Arcangeli /* If there is no mapped pte young don't collapse the page */ 193733c3fc71SVladimir Davydov if (pte_young(pteval) || 193833c3fc71SVladimir Davydov page_is_young(page) || PageReferenced(page) || 19398ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 194010359213SEbru Akagunduz referenced = true; 1941ba76149fSAndrea Arcangeli } 19427d2eba05SEbru Akagunduz if (likely(writable)) { 19437d2eba05SEbru Akagunduz if (likely(referenced)) { 19447d2eba05SEbru Akagunduz result = SCAN_SUCCEED; 19457d2eba05SEbru Akagunduz trace_mm_collapse_huge_page_isolate(page_to_pfn(page), none_or_zero, 19467d2eba05SEbru Akagunduz referenced, writable, result); 1947344aa35cSBob Liu return 1; 19487d2eba05SEbru Akagunduz } 19497d2eba05SEbru Akagunduz } else { 19507d2eba05SEbru Akagunduz result = SCAN_PAGE_RO; 19517d2eba05SEbru Akagunduz } 19527d2eba05SEbru Akagunduz 1953ba76149fSAndrea Arcangeli out: 1954344aa35cSBob Liu release_pte_pages(pte, _pte); 19557d2eba05SEbru Akagunduz trace_mm_collapse_huge_page_isolate(page_to_pfn(page), none_or_zero, 19567d2eba05SEbru Akagunduz referenced, writable, result); 1957344aa35cSBob Liu return 0; 1958ba76149fSAndrea Arcangeli } 1959ba76149fSAndrea Arcangeli 1960ba76149fSAndrea Arcangeli static void __collapse_huge_page_copy(pte_t *pte, struct page *page, 1961ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 1962ba76149fSAndrea Arcangeli unsigned long address, 1963ba76149fSAndrea Arcangeli spinlock_t *ptl) 1964ba76149fSAndrea Arcangeli { 1965ba76149fSAndrea Arcangeli pte_t *_pte; 1966ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { 1967ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 1968ba76149fSAndrea Arcangeli struct page *src_page; 1969ba76149fSAndrea Arcangeli 1970ca0984caSEbru Akagunduz if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { 1971ba76149fSAndrea Arcangeli clear_user_highpage(page, address); 1972ba76149fSAndrea Arcangeli add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); 1973ca0984caSEbru Akagunduz if (is_zero_pfn(pte_pfn(pteval))) { 1974ca0984caSEbru Akagunduz /* 1975ca0984caSEbru Akagunduz * ptl mostly unnecessary. 1976ca0984caSEbru Akagunduz */ 1977ca0984caSEbru Akagunduz spin_lock(ptl); 1978ca0984caSEbru Akagunduz /* 1979ca0984caSEbru Akagunduz * paravirt calls inside pte_clear here are 1980ca0984caSEbru Akagunduz * superfluous. 1981ca0984caSEbru Akagunduz */ 1982ca0984caSEbru Akagunduz pte_clear(vma->vm_mm, address, _pte); 1983ca0984caSEbru Akagunduz spin_unlock(ptl); 1984ca0984caSEbru Akagunduz } 1985ba76149fSAndrea Arcangeli } else { 1986ba76149fSAndrea Arcangeli src_page = pte_page(pteval); 1987ba76149fSAndrea Arcangeli copy_user_highpage(page, src_page, address, vma); 1988309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page); 1989ba76149fSAndrea Arcangeli release_pte_page(src_page); 1990ba76149fSAndrea Arcangeli /* 1991ba76149fSAndrea Arcangeli * ptl mostly unnecessary, but preempt has to 1992ba76149fSAndrea Arcangeli * be disabled to update the per-cpu stats 1993ba76149fSAndrea Arcangeli * inside page_remove_rmap(). 1994ba76149fSAndrea Arcangeli */ 1995ba76149fSAndrea Arcangeli spin_lock(ptl); 1996ba76149fSAndrea Arcangeli /* 1997ba76149fSAndrea Arcangeli * paravirt calls inside pte_clear here are 1998ba76149fSAndrea Arcangeli * superfluous. 1999ba76149fSAndrea Arcangeli */ 2000ba76149fSAndrea Arcangeli pte_clear(vma->vm_mm, address, _pte); 2001d281ee61SKirill A. Shutemov page_remove_rmap(src_page, false); 2002ba76149fSAndrea Arcangeli spin_unlock(ptl); 2003ba76149fSAndrea Arcangeli free_page_and_swap_cache(src_page); 2004ba76149fSAndrea Arcangeli } 2005ba76149fSAndrea Arcangeli 2006ba76149fSAndrea Arcangeli address += PAGE_SIZE; 2007ba76149fSAndrea Arcangeli page++; 2008ba76149fSAndrea Arcangeli } 2009ba76149fSAndrea Arcangeli } 2010ba76149fSAndrea Arcangeli 201126234f36SXiao Guangrong static void khugepaged_alloc_sleep(void) 201226234f36SXiao Guangrong { 2013bde43c6cSPetr Mladek DEFINE_WAIT(wait); 2014bde43c6cSPetr Mladek 2015bde43c6cSPetr Mladek add_wait_queue(&khugepaged_wait, &wait); 2016bde43c6cSPetr Mladek freezable_schedule_timeout_interruptible( 201726234f36SXiao Guangrong msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); 2018bde43c6cSPetr Mladek remove_wait_queue(&khugepaged_wait, &wait); 201926234f36SXiao Guangrong } 202026234f36SXiao Guangrong 20219f1b868aSBob Liu static int khugepaged_node_load[MAX_NUMNODES]; 20229f1b868aSBob Liu 202314a4e214SDavid Rientjes static bool khugepaged_scan_abort(int nid) 202414a4e214SDavid Rientjes { 202514a4e214SDavid Rientjes int i; 202614a4e214SDavid Rientjes 202714a4e214SDavid Rientjes /* 202814a4e214SDavid Rientjes * If zone_reclaim_mode is disabled, then no extra effort is made to 202914a4e214SDavid Rientjes * allocate memory locally. 203014a4e214SDavid Rientjes */ 203114a4e214SDavid Rientjes if (!zone_reclaim_mode) 203214a4e214SDavid Rientjes return false; 203314a4e214SDavid Rientjes 203414a4e214SDavid Rientjes /* If there is a count for this node already, it must be acceptable */ 203514a4e214SDavid Rientjes if (khugepaged_node_load[nid]) 203614a4e214SDavid Rientjes return false; 203714a4e214SDavid Rientjes 203814a4e214SDavid Rientjes for (i = 0; i < MAX_NUMNODES; i++) { 203914a4e214SDavid Rientjes if (!khugepaged_node_load[i]) 204014a4e214SDavid Rientjes continue; 204114a4e214SDavid Rientjes if (node_distance(nid, i) > RECLAIM_DISTANCE) 204214a4e214SDavid Rientjes return true; 204314a4e214SDavid Rientjes } 204414a4e214SDavid Rientjes return false; 204514a4e214SDavid Rientjes } 204614a4e214SDavid Rientjes 204726234f36SXiao Guangrong #ifdef CONFIG_NUMA 20489f1b868aSBob Liu static int khugepaged_find_target_node(void) 20499f1b868aSBob Liu { 20509f1b868aSBob Liu static int last_khugepaged_target_node = NUMA_NO_NODE; 20519f1b868aSBob Liu int nid, target_node = 0, max_value = 0; 20529f1b868aSBob Liu 20539f1b868aSBob Liu /* find first node with max normal pages hit */ 20549f1b868aSBob Liu for (nid = 0; nid < MAX_NUMNODES; nid++) 20559f1b868aSBob Liu if (khugepaged_node_load[nid] > max_value) { 20569f1b868aSBob Liu max_value = khugepaged_node_load[nid]; 20579f1b868aSBob Liu target_node = nid; 20589f1b868aSBob Liu } 20599f1b868aSBob Liu 20609f1b868aSBob Liu /* do some balance if several nodes have the same hit record */ 20619f1b868aSBob Liu if (target_node <= last_khugepaged_target_node) 20629f1b868aSBob Liu for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES; 20639f1b868aSBob Liu nid++) 20649f1b868aSBob Liu if (max_value == khugepaged_node_load[nid]) { 20659f1b868aSBob Liu target_node = nid; 20669f1b868aSBob Liu break; 20679f1b868aSBob Liu } 20689f1b868aSBob Liu 20699f1b868aSBob Liu last_khugepaged_target_node = target_node; 20709f1b868aSBob Liu return target_node; 20719f1b868aSBob Liu } 20729f1b868aSBob Liu 207326234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 207426234f36SXiao Guangrong { 207526234f36SXiao Guangrong if (IS_ERR(*hpage)) { 207626234f36SXiao Guangrong if (!*wait) 207726234f36SXiao Guangrong return false; 207826234f36SXiao Guangrong 207926234f36SXiao Guangrong *wait = false; 2080e3b4126cSXiao Guangrong *hpage = NULL; 208126234f36SXiao Guangrong khugepaged_alloc_sleep(); 208226234f36SXiao Guangrong } else if (*hpage) { 208326234f36SXiao Guangrong put_page(*hpage); 208426234f36SXiao Guangrong *hpage = NULL; 208526234f36SXiao Guangrong } 208626234f36SXiao Guangrong 208726234f36SXiao Guangrong return true; 208826234f36SXiao Guangrong } 208926234f36SXiao Guangrong 20903b363692SMichal Hocko static struct page * 20913b363692SMichal Hocko khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm, 2092d6669d68SAaron Tomlin unsigned long address, int node) 209326234f36SXiao Guangrong { 2094309381feSSasha Levin VM_BUG_ON_PAGE(*hpage, *hpage); 20958b164568SVlastimil Babka 209626234f36SXiao Guangrong /* 20978b164568SVlastimil Babka * Before allocating the hugepage, release the mmap_sem read lock. 20988b164568SVlastimil Babka * The allocation can take potentially a long time if it involves 20998b164568SVlastimil Babka * sync compaction, and we do not need to hold the mmap_sem during 21008b164568SVlastimil Babka * that. We will recheck the vma after taking it again in write mode. 210126234f36SXiao Guangrong */ 210226234f36SXiao Guangrong up_read(&mm->mmap_sem); 21038b164568SVlastimil Babka 210496db800fSVlastimil Babka *hpage = __alloc_pages_node(node, gfp, HPAGE_PMD_ORDER); 210526234f36SXiao Guangrong if (unlikely(!*hpage)) { 210626234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 210726234f36SXiao Guangrong *hpage = ERR_PTR(-ENOMEM); 210826234f36SXiao Guangrong return NULL; 210926234f36SXiao Guangrong } 211026234f36SXiao Guangrong 211126234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 211226234f36SXiao Guangrong return *hpage; 211326234f36SXiao Guangrong } 211426234f36SXiao Guangrong #else 21159f1b868aSBob Liu static int khugepaged_find_target_node(void) 21169f1b868aSBob Liu { 21179f1b868aSBob Liu return 0; 21189f1b868aSBob Liu } 21199f1b868aSBob Liu 212010dc4155SBob Liu static inline struct page *alloc_hugepage(int defrag) 212110dc4155SBob Liu { 212210dc4155SBob Liu return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), 212310dc4155SBob Liu HPAGE_PMD_ORDER); 212410dc4155SBob Liu } 212510dc4155SBob Liu 212626234f36SXiao Guangrong static struct page *khugepaged_alloc_hugepage(bool *wait) 212726234f36SXiao Guangrong { 212826234f36SXiao Guangrong struct page *hpage; 212926234f36SXiao Guangrong 213026234f36SXiao Guangrong do { 213126234f36SXiao Guangrong hpage = alloc_hugepage(khugepaged_defrag()); 213226234f36SXiao Guangrong if (!hpage) { 213326234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 213426234f36SXiao Guangrong if (!*wait) 213526234f36SXiao Guangrong return NULL; 213626234f36SXiao Guangrong 213726234f36SXiao Guangrong *wait = false; 213826234f36SXiao Guangrong khugepaged_alloc_sleep(); 213926234f36SXiao Guangrong } else 214026234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 214126234f36SXiao Guangrong } while (unlikely(!hpage) && likely(khugepaged_enabled())); 214226234f36SXiao Guangrong 214326234f36SXiao Guangrong return hpage; 214426234f36SXiao Guangrong } 214526234f36SXiao Guangrong 214626234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 214726234f36SXiao Guangrong { 214826234f36SXiao Guangrong if (!*hpage) 214926234f36SXiao Guangrong *hpage = khugepaged_alloc_hugepage(wait); 215026234f36SXiao Guangrong 215126234f36SXiao Guangrong if (unlikely(!*hpage)) 215226234f36SXiao Guangrong return false; 215326234f36SXiao Guangrong 215426234f36SXiao Guangrong return true; 215526234f36SXiao Guangrong } 215626234f36SXiao Guangrong 21573b363692SMichal Hocko static struct page * 21583b363692SMichal Hocko khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm, 2159d6669d68SAaron Tomlin unsigned long address, int node) 216026234f36SXiao Guangrong { 216126234f36SXiao Guangrong up_read(&mm->mmap_sem); 216226234f36SXiao Guangrong VM_BUG_ON(!*hpage); 21633b363692SMichal Hocko 216426234f36SXiao Guangrong return *hpage; 216526234f36SXiao Guangrong } 216626234f36SXiao Guangrong #endif 216726234f36SXiao Guangrong 2168fa475e51SBob Liu static bool hugepage_vma_check(struct vm_area_struct *vma) 2169fa475e51SBob Liu { 2170fa475e51SBob Liu if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || 2171fa475e51SBob Liu (vma->vm_flags & VM_NOHUGEPAGE)) 2172fa475e51SBob Liu return false; 21737479df6dSKirill A. Shutemov if (vma->vm_flags & VM_LOCKED) 21747479df6dSKirill A. Shutemov return false; 2175fa475e51SBob Liu if (!vma->anon_vma || vma->vm_ops) 2176fa475e51SBob Liu return false; 2177fa475e51SBob Liu if (is_vma_temporary_stack(vma)) 2178fa475e51SBob Liu return false; 217981d1b09cSSasha Levin VM_BUG_ON_VMA(vma->vm_flags & VM_NO_THP, vma); 2180fa475e51SBob Liu return true; 2181fa475e51SBob Liu } 2182fa475e51SBob Liu 2183ba76149fSAndrea Arcangeli static void collapse_huge_page(struct mm_struct *mm, 2184ba76149fSAndrea Arcangeli unsigned long address, 2185ce83d217SAndrea Arcangeli struct page **hpage, 21865c4b4be3SAndi Kleen struct vm_area_struct *vma, 21875c4b4be3SAndi Kleen int node) 2188ba76149fSAndrea Arcangeli { 2189ba76149fSAndrea Arcangeli pmd_t *pmd, _pmd; 2190ba76149fSAndrea Arcangeli pte_t *pte; 2191ba76149fSAndrea Arcangeli pgtable_t pgtable; 2192ba76149fSAndrea Arcangeli struct page *new_page; 2193c4088ebdSKirill A. Shutemov spinlock_t *pmd_ptl, *pte_ptl; 21947d2eba05SEbru Akagunduz int isolated, result = 0; 2195ba76149fSAndrea Arcangeli unsigned long hstart, hend; 219600501b53SJohannes Weiner struct mem_cgroup *memcg; 21972ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 21982ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 21993b363692SMichal Hocko gfp_t gfp; 2200ba76149fSAndrea Arcangeli 2201ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 2202692e0b35SAndrea Arcangeli 22033b363692SMichal Hocko /* Only allocate from the target node */ 22043b363692SMichal Hocko gfp = alloc_hugepage_gfpmask(khugepaged_defrag(), __GFP_OTHER_NODE) | 22053b363692SMichal Hocko __GFP_THISNODE; 22063b363692SMichal Hocko 220726234f36SXiao Guangrong /* release the mmap_sem read lock. */ 2208d6669d68SAaron Tomlin new_page = khugepaged_alloc_page(hpage, gfp, mm, address, node); 22097d2eba05SEbru Akagunduz if (!new_page) { 22107d2eba05SEbru Akagunduz result = SCAN_ALLOC_HUGE_PAGE_FAIL; 22117d2eba05SEbru Akagunduz goto out_nolock; 22127d2eba05SEbru Akagunduz } 2213ce83d217SAndrea Arcangeli 2214f627c2f5SKirill A. Shutemov if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp, &memcg, true))) { 22157d2eba05SEbru Akagunduz result = SCAN_CGROUP_CHARGE_FAIL; 22167d2eba05SEbru Akagunduz goto out_nolock; 22177d2eba05SEbru Akagunduz } 2218ba76149fSAndrea Arcangeli 2219ba76149fSAndrea Arcangeli /* 2220ba76149fSAndrea Arcangeli * Prevent all access to pagetables with the exception of 2221ba76149fSAndrea Arcangeli * gup_fast later hanlded by the ptep_clear_flush and the VM 2222ba76149fSAndrea Arcangeli * handled by the anon_vma lock + PG_lock. 2223ba76149fSAndrea Arcangeli */ 2224ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 22257d2eba05SEbru Akagunduz if (unlikely(khugepaged_test_exit(mm))) { 22267d2eba05SEbru Akagunduz result = SCAN_ANY_PROCESS; 2227ba76149fSAndrea Arcangeli goto out; 22287d2eba05SEbru Akagunduz } 2229ba76149fSAndrea Arcangeli 2230ba76149fSAndrea Arcangeli vma = find_vma(mm, address); 22317d2eba05SEbru Akagunduz if (!vma) { 22327d2eba05SEbru Akagunduz result = SCAN_VMA_NULL; 2233a8f531ebSLibin goto out; 22347d2eba05SEbru Akagunduz } 2235ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2236ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 22377d2eba05SEbru Akagunduz if (address < hstart || address + HPAGE_PMD_SIZE > hend) { 22387d2eba05SEbru Akagunduz result = SCAN_ADDRESS_RANGE; 2239ba76149fSAndrea Arcangeli goto out; 22407d2eba05SEbru Akagunduz } 22417d2eba05SEbru Akagunduz if (!hugepage_vma_check(vma)) { 22427d2eba05SEbru Akagunduz result = SCAN_VMA_CHECK; 2243ba76149fSAndrea Arcangeli goto out; 22447d2eba05SEbru Akagunduz } 22456219049aSBob Liu pmd = mm_find_pmd(mm, address); 22467d2eba05SEbru Akagunduz if (!pmd) { 22477d2eba05SEbru Akagunduz result = SCAN_PMD_NULL; 2248ba76149fSAndrea Arcangeli goto out; 22497d2eba05SEbru Akagunduz } 2250ba76149fSAndrea Arcangeli 22514fc3f1d6SIngo Molnar anon_vma_lock_write(vma->anon_vma); 2252ba76149fSAndrea Arcangeli 2253ba76149fSAndrea Arcangeli pte = pte_offset_map(pmd, address); 2254c4088ebdSKirill A. Shutemov pte_ptl = pte_lockptr(mm, pmd); 2255ba76149fSAndrea Arcangeli 22562ec74c3eSSagi Grimberg mmun_start = address; 22572ec74c3eSSagi Grimberg mmun_end = address + HPAGE_PMD_SIZE; 22582ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2259c4088ebdSKirill A. Shutemov pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */ 2260ba76149fSAndrea Arcangeli /* 2261ba76149fSAndrea Arcangeli * After this gup_fast can't run anymore. This also removes 2262ba76149fSAndrea Arcangeli * any huge TLB entry from the CPU so we won't allow 2263ba76149fSAndrea Arcangeli * huge and small TLB entries for the same virtual address 2264ba76149fSAndrea Arcangeli * to avoid the risk of CPU bugs in that area. 2265ba76149fSAndrea Arcangeli */ 226615a25b2eSAneesh Kumar K.V _pmd = pmdp_collapse_flush(vma, address, pmd); 2267c4088ebdSKirill A. Shutemov spin_unlock(pmd_ptl); 22682ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2269ba76149fSAndrea Arcangeli 2270c4088ebdSKirill A. Shutemov spin_lock(pte_ptl); 2271ba76149fSAndrea Arcangeli isolated = __collapse_huge_page_isolate(vma, address, pte); 2272c4088ebdSKirill A. Shutemov spin_unlock(pte_ptl); 2273ba76149fSAndrea Arcangeli 2274ba76149fSAndrea Arcangeli if (unlikely(!isolated)) { 2275453c7192SJohannes Weiner pte_unmap(pte); 2276c4088ebdSKirill A. Shutemov spin_lock(pmd_ptl); 2277ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 22787c342512SAneesh Kumar K.V /* 22797c342512SAneesh Kumar K.V * We can only use set_pmd_at when establishing 22807c342512SAneesh Kumar K.V * hugepmds and never for establishing regular pmds that 22817c342512SAneesh Kumar K.V * points to regular pagetables. Use pmd_populate for that 22827c342512SAneesh Kumar K.V */ 22837c342512SAneesh Kumar K.V pmd_populate(mm, pmd, pmd_pgtable(_pmd)); 2284c4088ebdSKirill A. Shutemov spin_unlock(pmd_ptl); 228508b52706SKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 22867d2eba05SEbru Akagunduz result = SCAN_FAIL; 2287ce83d217SAndrea Arcangeli goto out; 2288ba76149fSAndrea Arcangeli } 2289ba76149fSAndrea Arcangeli 2290ba76149fSAndrea Arcangeli /* 2291ba76149fSAndrea Arcangeli * All pages are isolated and locked so anon_vma rmap 2292ba76149fSAndrea Arcangeli * can't run anymore. 2293ba76149fSAndrea Arcangeli */ 229408b52706SKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2295ba76149fSAndrea Arcangeli 2296c4088ebdSKirill A. Shutemov __collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl); 2297453c7192SJohannes Weiner pte_unmap(pte); 2298ba76149fSAndrea Arcangeli __SetPageUptodate(new_page); 2299ba76149fSAndrea Arcangeli pgtable = pmd_pgtable(_pmd); 2300ba76149fSAndrea Arcangeli 23013122359aSKirill A. Shutemov _pmd = mk_huge_pmd(new_page, vma->vm_page_prot); 23023122359aSKirill A. Shutemov _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); 2303ba76149fSAndrea Arcangeli 2304ba76149fSAndrea Arcangeli /* 2305ba76149fSAndrea Arcangeli * spin_lock() below is not the equivalent of smp_wmb(), so 2306ba76149fSAndrea Arcangeli * this is needed to avoid the copy_huge_page writes to become 2307ba76149fSAndrea Arcangeli * visible after the set_pmd_at() write. 2308ba76149fSAndrea Arcangeli */ 2309ba76149fSAndrea Arcangeli smp_wmb(); 2310ba76149fSAndrea Arcangeli 2311c4088ebdSKirill A. Shutemov spin_lock(pmd_ptl); 2312ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 2313d281ee61SKirill A. Shutemov page_add_new_anon_rmap(new_page, vma, address, true); 2314f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(new_page, memcg, false, true); 231500501b53SJohannes Weiner lru_cache_add_active_or_unevictable(new_page, vma); 2316fce144b4SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 2317ba76149fSAndrea Arcangeli set_pmd_at(mm, address, pmd, _pmd); 2318b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 2319c4088ebdSKirill A. Shutemov spin_unlock(pmd_ptl); 2320ba76149fSAndrea Arcangeli 2321ba76149fSAndrea Arcangeli *hpage = NULL; 2322420256efSXiao Guangrong 2323ba76149fSAndrea Arcangeli khugepaged_pages_collapsed++; 23247d2eba05SEbru Akagunduz result = SCAN_SUCCEED; 2325ce83d217SAndrea Arcangeli out_up_write: 2326ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 23277d2eba05SEbru Akagunduz trace_mm_collapse_huge_page(mm, isolated, result); 23280bbbc0b3SAndrea Arcangeli return; 23290bbbc0b3SAndrea Arcangeli 23307d2eba05SEbru Akagunduz out_nolock: 23317d2eba05SEbru Akagunduz trace_mm_collapse_huge_page(mm, isolated, result); 23327d2eba05SEbru Akagunduz return; 2333ce83d217SAndrea Arcangeli out: 2334f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(new_page, memcg, true); 2335ce83d217SAndrea Arcangeli goto out_up_write; 2336ba76149fSAndrea Arcangeli } 2337ba76149fSAndrea Arcangeli 2338ba76149fSAndrea Arcangeli static int khugepaged_scan_pmd(struct mm_struct *mm, 2339ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 2340ba76149fSAndrea Arcangeli unsigned long address, 2341ba76149fSAndrea Arcangeli struct page **hpage) 2342ba76149fSAndrea Arcangeli { 2343ba76149fSAndrea Arcangeli pmd_t *pmd; 2344ba76149fSAndrea Arcangeli pte_t *pte, *_pte; 23457d2eba05SEbru Akagunduz int ret = 0, none_or_zero = 0, result = 0; 23467d2eba05SEbru Akagunduz struct page *page = NULL; 2347ba76149fSAndrea Arcangeli unsigned long _address; 2348ba76149fSAndrea Arcangeli spinlock_t *ptl; 234900ef2d2fSDavid Rientjes int node = NUMA_NO_NODE; 235010359213SEbru Akagunduz bool writable = false, referenced = false; 2351ba76149fSAndrea Arcangeli 2352ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 2353ba76149fSAndrea Arcangeli 23546219049aSBob Liu pmd = mm_find_pmd(mm, address); 23557d2eba05SEbru Akagunduz if (!pmd) { 23567d2eba05SEbru Akagunduz result = SCAN_PMD_NULL; 2357ba76149fSAndrea Arcangeli goto out; 23587d2eba05SEbru Akagunduz } 2359ba76149fSAndrea Arcangeli 23609f1b868aSBob Liu memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load)); 2361ba76149fSAndrea Arcangeli pte = pte_offset_map_lock(mm, pmd, address, &ptl); 2362ba76149fSAndrea Arcangeli for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; 2363ba76149fSAndrea Arcangeli _pte++, _address += PAGE_SIZE) { 2364ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2365ca0984caSEbru Akagunduz if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { 2366c1294d05SAndrea Arcangeli if (!userfaultfd_armed(vma) && 23677d2eba05SEbru Akagunduz ++none_or_zero <= khugepaged_max_ptes_none) { 2368ba76149fSAndrea Arcangeli continue; 23697d2eba05SEbru Akagunduz } else { 23707d2eba05SEbru Akagunduz result = SCAN_EXCEED_NONE_PTE; 2371ba76149fSAndrea Arcangeli goto out_unmap; 2372ba76149fSAndrea Arcangeli } 23737d2eba05SEbru Akagunduz } 23747d2eba05SEbru Akagunduz if (!pte_present(pteval)) { 23757d2eba05SEbru Akagunduz result = SCAN_PTE_NON_PRESENT; 2376ba76149fSAndrea Arcangeli goto out_unmap; 23777d2eba05SEbru Akagunduz } 237810359213SEbru Akagunduz if (pte_write(pteval)) 237910359213SEbru Akagunduz writable = true; 238010359213SEbru Akagunduz 2381ba76149fSAndrea Arcangeli page = vm_normal_page(vma, _address, pteval); 23827d2eba05SEbru Akagunduz if (unlikely(!page)) { 23837d2eba05SEbru Akagunduz result = SCAN_PAGE_NULL; 2384ba76149fSAndrea Arcangeli goto out_unmap; 23857d2eba05SEbru Akagunduz } 2386b1caa957SKirill A. Shutemov 2387b1caa957SKirill A. Shutemov /* TODO: teach khugepaged to collapse THP mapped with pte */ 2388b1caa957SKirill A. Shutemov if (PageCompound(page)) { 2389b1caa957SKirill A. Shutemov result = SCAN_PAGE_COMPOUND; 2390b1caa957SKirill A. Shutemov goto out_unmap; 2391b1caa957SKirill A. Shutemov } 2392b1caa957SKirill A. Shutemov 23935c4b4be3SAndi Kleen /* 23949f1b868aSBob Liu * Record which node the original page is from and save this 23959f1b868aSBob Liu * information to khugepaged_node_load[]. 23969f1b868aSBob Liu * Khupaged will allocate hugepage from the node has the max 23979f1b868aSBob Liu * hit record. 23985c4b4be3SAndi Kleen */ 23995c4b4be3SAndi Kleen node = page_to_nid(page); 24007d2eba05SEbru Akagunduz if (khugepaged_scan_abort(node)) { 24017d2eba05SEbru Akagunduz result = SCAN_SCAN_ABORT; 240214a4e214SDavid Rientjes goto out_unmap; 24037d2eba05SEbru Akagunduz } 24049f1b868aSBob Liu khugepaged_node_load[node]++; 24057d2eba05SEbru Akagunduz if (!PageLRU(page)) { 24067d2eba05SEbru Akagunduz result = SCAN_SCAN_ABORT; 2407ba76149fSAndrea Arcangeli goto out_unmap; 24087d2eba05SEbru Akagunduz } 24097d2eba05SEbru Akagunduz if (PageLocked(page)) { 24107d2eba05SEbru Akagunduz result = SCAN_PAGE_LOCK; 24117d2eba05SEbru Akagunduz goto out_unmap; 24127d2eba05SEbru Akagunduz } 24137d2eba05SEbru Akagunduz if (!PageAnon(page)) { 24147d2eba05SEbru Akagunduz result = SCAN_PAGE_ANON; 24157d2eba05SEbru Akagunduz goto out_unmap; 24167d2eba05SEbru Akagunduz } 24177d2eba05SEbru Akagunduz 241810359213SEbru Akagunduz /* 241910359213SEbru Akagunduz * cannot use mapcount: can't collapse if there's a gup pin. 242010359213SEbru Akagunduz * The page must only be referenced by the scanned process 242110359213SEbru Akagunduz * and page swap cache. 242210359213SEbru Akagunduz */ 24237d2eba05SEbru Akagunduz if (page_count(page) != 1 + !!PageSwapCache(page)) { 24247d2eba05SEbru Akagunduz result = SCAN_PAGE_COUNT; 2425ba76149fSAndrea Arcangeli goto out_unmap; 24267d2eba05SEbru Akagunduz } 242733c3fc71SVladimir Davydov if (pte_young(pteval) || 242833c3fc71SVladimir Davydov page_is_young(page) || PageReferenced(page) || 24298ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 243010359213SEbru Akagunduz referenced = true; 2431ba76149fSAndrea Arcangeli } 24327d2eba05SEbru Akagunduz if (writable) { 24337d2eba05SEbru Akagunduz if (referenced) { 24347d2eba05SEbru Akagunduz result = SCAN_SUCCEED; 2435ba76149fSAndrea Arcangeli ret = 1; 24367d2eba05SEbru Akagunduz } else { 24377d2eba05SEbru Akagunduz result = SCAN_NO_REFERENCED_PAGE; 24387d2eba05SEbru Akagunduz } 24397d2eba05SEbru Akagunduz } else { 24407d2eba05SEbru Akagunduz result = SCAN_PAGE_RO; 24417d2eba05SEbru Akagunduz } 2442ba76149fSAndrea Arcangeli out_unmap: 2443ba76149fSAndrea Arcangeli pte_unmap_unlock(pte, ptl); 24449f1b868aSBob Liu if (ret) { 24459f1b868aSBob Liu node = khugepaged_find_target_node(); 2446ce83d217SAndrea Arcangeli /* collapse_huge_page will return with the mmap_sem released */ 24475c4b4be3SAndi Kleen collapse_huge_page(mm, address, hpage, vma, node); 24489f1b868aSBob Liu } 2449ba76149fSAndrea Arcangeli out: 24507d2eba05SEbru Akagunduz trace_mm_khugepaged_scan_pmd(mm, page_to_pfn(page), writable, referenced, 24517d2eba05SEbru Akagunduz none_or_zero, result); 2452ba76149fSAndrea Arcangeli return ret; 2453ba76149fSAndrea Arcangeli } 2454ba76149fSAndrea Arcangeli 2455ba76149fSAndrea Arcangeli static void collect_mm_slot(struct mm_slot *mm_slot) 2456ba76149fSAndrea Arcangeli { 2457ba76149fSAndrea Arcangeli struct mm_struct *mm = mm_slot->mm; 2458ba76149fSAndrea Arcangeli 2459b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2460ba76149fSAndrea Arcangeli 2461ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm)) { 2462ba76149fSAndrea Arcangeli /* free mm_slot */ 246343b5fbbdSSasha Levin hash_del(&mm_slot->hash); 2464ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 2465ba76149fSAndrea Arcangeli 2466ba76149fSAndrea Arcangeli /* 2467ba76149fSAndrea Arcangeli * Not strictly needed because the mm exited already. 2468ba76149fSAndrea Arcangeli * 2469ba76149fSAndrea Arcangeli * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 2470ba76149fSAndrea Arcangeli */ 2471ba76149fSAndrea Arcangeli 2472ba76149fSAndrea Arcangeli /* khugepaged_mm_lock actually not necessary for the below */ 2473ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2474ba76149fSAndrea Arcangeli mmdrop(mm); 2475ba76149fSAndrea Arcangeli } 2476ba76149fSAndrea Arcangeli } 2477ba76149fSAndrea Arcangeli 2478ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_mm_slot(unsigned int pages, 2479ba76149fSAndrea Arcangeli struct page **hpage) 24802f1da642SH Hartley Sweeten __releases(&khugepaged_mm_lock) 24812f1da642SH Hartley Sweeten __acquires(&khugepaged_mm_lock) 2482ba76149fSAndrea Arcangeli { 2483ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2484ba76149fSAndrea Arcangeli struct mm_struct *mm; 2485ba76149fSAndrea Arcangeli struct vm_area_struct *vma; 2486ba76149fSAndrea Arcangeli int progress = 0; 2487ba76149fSAndrea Arcangeli 2488ba76149fSAndrea Arcangeli VM_BUG_ON(!pages); 2489b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2490ba76149fSAndrea Arcangeli 2491ba76149fSAndrea Arcangeli if (khugepaged_scan.mm_slot) 2492ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2493ba76149fSAndrea Arcangeli else { 2494ba76149fSAndrea Arcangeli mm_slot = list_entry(khugepaged_scan.mm_head.next, 2495ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2496ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2497ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = mm_slot; 2498ba76149fSAndrea Arcangeli } 2499ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2500ba76149fSAndrea Arcangeli 2501ba76149fSAndrea Arcangeli mm = mm_slot->mm; 2502ba76149fSAndrea Arcangeli down_read(&mm->mmap_sem); 2503ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2504ba76149fSAndrea Arcangeli vma = NULL; 2505ba76149fSAndrea Arcangeli else 2506ba76149fSAndrea Arcangeli vma = find_vma(mm, khugepaged_scan.address); 2507ba76149fSAndrea Arcangeli 2508ba76149fSAndrea Arcangeli progress++; 2509ba76149fSAndrea Arcangeli for (; vma; vma = vma->vm_next) { 2510ba76149fSAndrea Arcangeli unsigned long hstart, hend; 2511ba76149fSAndrea Arcangeli 2512ba76149fSAndrea Arcangeli cond_resched(); 2513ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) { 2514ba76149fSAndrea Arcangeli progress++; 2515ba76149fSAndrea Arcangeli break; 2516ba76149fSAndrea Arcangeli } 2517fa475e51SBob Liu if (!hugepage_vma_check(vma)) { 2518a7d6e4ecSAndrea Arcangeli skip: 2519ba76149fSAndrea Arcangeli progress++; 2520ba76149fSAndrea Arcangeli continue; 2521ba76149fSAndrea Arcangeli } 2522ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2523ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2524a7d6e4ecSAndrea Arcangeli if (hstart >= hend) 2525a7d6e4ecSAndrea Arcangeli goto skip; 2526a7d6e4ecSAndrea Arcangeli if (khugepaged_scan.address > hend) 2527a7d6e4ecSAndrea Arcangeli goto skip; 2528ba76149fSAndrea Arcangeli if (khugepaged_scan.address < hstart) 2529ba76149fSAndrea Arcangeli khugepaged_scan.address = hstart; 2530a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); 2531ba76149fSAndrea Arcangeli 2532ba76149fSAndrea Arcangeli while (khugepaged_scan.address < hend) { 2533ba76149fSAndrea Arcangeli int ret; 2534ba76149fSAndrea Arcangeli cond_resched(); 2535ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2536ba76149fSAndrea Arcangeli goto breakouterloop; 2537ba76149fSAndrea Arcangeli 2538ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address < hstart || 2539ba76149fSAndrea Arcangeli khugepaged_scan.address + HPAGE_PMD_SIZE > 2540ba76149fSAndrea Arcangeli hend); 2541ba76149fSAndrea Arcangeli ret = khugepaged_scan_pmd(mm, vma, 2542ba76149fSAndrea Arcangeli khugepaged_scan.address, 2543ba76149fSAndrea Arcangeli hpage); 2544ba76149fSAndrea Arcangeli /* move to next address */ 2545ba76149fSAndrea Arcangeli khugepaged_scan.address += HPAGE_PMD_SIZE; 2546ba76149fSAndrea Arcangeli progress += HPAGE_PMD_NR; 2547ba76149fSAndrea Arcangeli if (ret) 2548ba76149fSAndrea Arcangeli /* we released mmap_sem so break loop */ 2549ba76149fSAndrea Arcangeli goto breakouterloop_mmap_sem; 2550ba76149fSAndrea Arcangeli if (progress >= pages) 2551ba76149fSAndrea Arcangeli goto breakouterloop; 2552ba76149fSAndrea Arcangeli } 2553ba76149fSAndrea Arcangeli } 2554ba76149fSAndrea Arcangeli breakouterloop: 2555ba76149fSAndrea Arcangeli up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ 2556ba76149fSAndrea Arcangeli breakouterloop_mmap_sem: 2557ba76149fSAndrea Arcangeli 2558ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2559a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); 2560ba76149fSAndrea Arcangeli /* 2561ba76149fSAndrea Arcangeli * Release the current mm_slot if this mm is about to die, or 2562ba76149fSAndrea Arcangeli * if we scanned all vmas of this mm. 2563ba76149fSAndrea Arcangeli */ 2564ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm) || !vma) { 2565ba76149fSAndrea Arcangeli /* 2566ba76149fSAndrea Arcangeli * Make sure that if mm_users is reaching zero while 2567ba76149fSAndrea Arcangeli * khugepaged runs here, khugepaged_exit will find 2568ba76149fSAndrea Arcangeli * mm_slot not pointing to the exiting mm. 2569ba76149fSAndrea Arcangeli */ 2570ba76149fSAndrea Arcangeli if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { 2571ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = list_entry( 2572ba76149fSAndrea Arcangeli mm_slot->mm_node.next, 2573ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2574ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2575ba76149fSAndrea Arcangeli } else { 2576ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2577ba76149fSAndrea Arcangeli khugepaged_full_scans++; 2578ba76149fSAndrea Arcangeli } 2579ba76149fSAndrea Arcangeli 2580ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2581ba76149fSAndrea Arcangeli } 2582ba76149fSAndrea Arcangeli 2583ba76149fSAndrea Arcangeli return progress; 2584ba76149fSAndrea Arcangeli } 2585ba76149fSAndrea Arcangeli 2586ba76149fSAndrea Arcangeli static int khugepaged_has_work(void) 2587ba76149fSAndrea Arcangeli { 2588ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) && 2589ba76149fSAndrea Arcangeli khugepaged_enabled(); 2590ba76149fSAndrea Arcangeli } 2591ba76149fSAndrea Arcangeli 2592ba76149fSAndrea Arcangeli static int khugepaged_wait_event(void) 2593ba76149fSAndrea Arcangeli { 2594ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) || 25952017c0bfSXiao Guangrong kthread_should_stop(); 2596ba76149fSAndrea Arcangeli } 2597ba76149fSAndrea Arcangeli 2598d516904bSXiao Guangrong static void khugepaged_do_scan(void) 2599d516904bSXiao Guangrong { 2600d516904bSXiao Guangrong struct page *hpage = NULL; 2601ba76149fSAndrea Arcangeli unsigned int progress = 0, pass_through_head = 0; 2602ba76149fSAndrea Arcangeli unsigned int pages = khugepaged_pages_to_scan; 2603d516904bSXiao Guangrong bool wait = true; 2604ba76149fSAndrea Arcangeli 2605ba76149fSAndrea Arcangeli barrier(); /* write khugepaged_pages_to_scan to local stack */ 2606ba76149fSAndrea Arcangeli 2607ba76149fSAndrea Arcangeli while (progress < pages) { 260826234f36SXiao Guangrong if (!khugepaged_prealloc_page(&hpage, &wait)) 260926234f36SXiao Guangrong break; 2610d516904bSXiao Guangrong 2611420256efSXiao Guangrong cond_resched(); 2612ba76149fSAndrea Arcangeli 2613cd092411SJiri Kosina if (unlikely(kthread_should_stop() || try_to_freeze())) 2614878aee7dSAndrea Arcangeli break; 2615878aee7dSAndrea Arcangeli 2616ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2617ba76149fSAndrea Arcangeli if (!khugepaged_scan.mm_slot) 2618ba76149fSAndrea Arcangeli pass_through_head++; 2619ba76149fSAndrea Arcangeli if (khugepaged_has_work() && 2620ba76149fSAndrea Arcangeli pass_through_head < 2) 2621ba76149fSAndrea Arcangeli progress += khugepaged_scan_mm_slot(pages - progress, 2622d516904bSXiao Guangrong &hpage); 2623ba76149fSAndrea Arcangeli else 2624ba76149fSAndrea Arcangeli progress = pages; 2625ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2626ba76149fSAndrea Arcangeli } 2627ba76149fSAndrea Arcangeli 2628d516904bSXiao Guangrong if (!IS_ERR_OR_NULL(hpage)) 2629d516904bSXiao Guangrong put_page(hpage); 2630ba76149fSAndrea Arcangeli } 26310bbbc0b3SAndrea Arcangeli 26322017c0bfSXiao Guangrong static void khugepaged_wait_work(void) 26332017c0bfSXiao Guangrong { 26342017c0bfSXiao Guangrong if (khugepaged_has_work()) { 26352017c0bfSXiao Guangrong if (!khugepaged_scan_sleep_millisecs) 26362017c0bfSXiao Guangrong return; 26372017c0bfSXiao Guangrong 26382017c0bfSXiao Guangrong wait_event_freezable_timeout(khugepaged_wait, 26392017c0bfSXiao Guangrong kthread_should_stop(), 26402017c0bfSXiao Guangrong msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); 26412017c0bfSXiao Guangrong return; 26422017c0bfSXiao Guangrong } 26432017c0bfSXiao Guangrong 26442017c0bfSXiao Guangrong if (khugepaged_enabled()) 26452017c0bfSXiao Guangrong wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); 26462017c0bfSXiao Guangrong } 26472017c0bfSXiao Guangrong 2648ba76149fSAndrea Arcangeli static int khugepaged(void *none) 2649ba76149fSAndrea Arcangeli { 2650ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2651ba76149fSAndrea Arcangeli 2652878aee7dSAndrea Arcangeli set_freezable(); 26538698a745SDongsheng Yang set_user_nice(current, MAX_NICE); 2654ba76149fSAndrea Arcangeli 2655b7231789SXiao Guangrong while (!kthread_should_stop()) { 2656b7231789SXiao Guangrong khugepaged_do_scan(); 2657b7231789SXiao Guangrong khugepaged_wait_work(); 2658b7231789SXiao Guangrong } 2659ba76149fSAndrea Arcangeli 2660ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2661ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2662ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2663ba76149fSAndrea Arcangeli if (mm_slot) 2664ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2665ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2666ba76149fSAndrea Arcangeli return 0; 2667ba76149fSAndrea Arcangeli } 2668ba76149fSAndrea Arcangeli 266978ddc534SKirill A. Shutemov static void split_huge_pmd_address(struct vm_area_struct *vma, 267094fcc585SAndrea Arcangeli unsigned long address) 267194fcc585SAndrea Arcangeli { 2672f72e7dcdSHugh Dickins pgd_t *pgd; 2673f72e7dcdSHugh Dickins pud_t *pud; 267494fcc585SAndrea Arcangeli pmd_t *pmd; 267594fcc585SAndrea Arcangeli 267694fcc585SAndrea Arcangeli VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); 267794fcc585SAndrea Arcangeli 267878ddc534SKirill A. Shutemov pgd = pgd_offset(vma->vm_mm, address); 2679f72e7dcdSHugh Dickins if (!pgd_present(*pgd)) 2680f72e7dcdSHugh Dickins return; 2681f72e7dcdSHugh Dickins 2682f72e7dcdSHugh Dickins pud = pud_offset(pgd, address); 2683f72e7dcdSHugh Dickins if (!pud_present(*pud)) 2684f72e7dcdSHugh Dickins return; 2685f72e7dcdSHugh Dickins 2686f72e7dcdSHugh Dickins pmd = pmd_offset(pud, address); 268778ddc534SKirill A. Shutemov if (!pmd_present(*pmd) || !pmd_trans_huge(*pmd)) 268894fcc585SAndrea Arcangeli return; 268994fcc585SAndrea Arcangeli /* 269094fcc585SAndrea Arcangeli * Caller holds the mmap_sem write mode, so a huge pmd cannot 269194fcc585SAndrea Arcangeli * materialize from under us. 269294fcc585SAndrea Arcangeli */ 2693ad0bed24SKirill A. Shutemov split_huge_pmd(vma, pmd, address); 269494fcc585SAndrea Arcangeli } 269594fcc585SAndrea Arcangeli 2696e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 269794fcc585SAndrea Arcangeli unsigned long start, 269894fcc585SAndrea Arcangeli unsigned long end, 269994fcc585SAndrea Arcangeli long adjust_next) 270094fcc585SAndrea Arcangeli { 270194fcc585SAndrea Arcangeli /* 270294fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 270394fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 270494fcc585SAndrea Arcangeli * an huge pmd. 270594fcc585SAndrea Arcangeli */ 270694fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 270794fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 270894fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 270978ddc534SKirill A. Shutemov split_huge_pmd_address(vma, start); 271094fcc585SAndrea Arcangeli 271194fcc585SAndrea Arcangeli /* 271294fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 271394fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 271494fcc585SAndrea Arcangeli * an huge pmd. 271594fcc585SAndrea Arcangeli */ 271694fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 271794fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 271894fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 271978ddc534SKirill A. Shutemov split_huge_pmd_address(vma, end); 272094fcc585SAndrea Arcangeli 272194fcc585SAndrea Arcangeli /* 272294fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 272394fcc585SAndrea Arcangeli * vm_next->vm_start isn't page aligned and it could previously 272494fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 272594fcc585SAndrea Arcangeli */ 272694fcc585SAndrea Arcangeli if (adjust_next > 0) { 272794fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 272894fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 272994fcc585SAndrea Arcangeli nstart += adjust_next << PAGE_SHIFT; 273094fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 273194fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 273294fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 273378ddc534SKirill A. Shutemov split_huge_pmd_address(next, nstart); 273494fcc585SAndrea Arcangeli } 273594fcc585SAndrea Arcangeli } 2736