171e3aac0SAndrea Arcangeli /* 271e3aac0SAndrea Arcangeli * Copyright (C) 2009 Red Hat, Inc. 371e3aac0SAndrea Arcangeli * 471e3aac0SAndrea Arcangeli * This work is licensed under the terms of the GNU GPL, version 2. See 571e3aac0SAndrea Arcangeli * the COPYING file in the top-level directory. 671e3aac0SAndrea Arcangeli */ 771e3aac0SAndrea Arcangeli 871e3aac0SAndrea Arcangeli #include <linux/mm.h> 971e3aac0SAndrea Arcangeli #include <linux/sched.h> 1071e3aac0SAndrea Arcangeli #include <linux/highmem.h> 1171e3aac0SAndrea Arcangeli #include <linux/hugetlb.h> 1271e3aac0SAndrea Arcangeli #include <linux/mmu_notifier.h> 1371e3aac0SAndrea Arcangeli #include <linux/rmap.h> 1471e3aac0SAndrea Arcangeli #include <linux/swap.h> 15ba76149fSAndrea Arcangeli #include <linux/mm_inline.h> 16ba76149fSAndrea Arcangeli #include <linux/kthread.h> 17ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 18878aee7dSAndrea Arcangeli #include <linux/freezer.h> 19a664b2d8SAndrea Arcangeli #include <linux/mman.h> 20325adeb5SRalf Baechle #include <linux/pagemap.h> 2171e3aac0SAndrea Arcangeli #include <asm/tlb.h> 2271e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 2371e3aac0SAndrea Arcangeli #include "internal.h" 2471e3aac0SAndrea Arcangeli 25ba76149fSAndrea Arcangeli /* 26ba76149fSAndrea Arcangeli * By default transparent hugepage support is enabled for all mappings 27ba76149fSAndrea Arcangeli * and khugepaged scans all mappings. Defrag is only invoked by 28ba76149fSAndrea Arcangeli * khugepaged hugepage allocations and by page faults inside 29ba76149fSAndrea Arcangeli * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived 30ba76149fSAndrea Arcangeli * allocations. 31ba76149fSAndrea Arcangeli */ 3271e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 3313ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 34ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 3513ece886SAndrea Arcangeli #endif 3613ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 3713ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 3813ece886SAndrea Arcangeli #endif 39d39d33c3SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| 40ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 41ba76149fSAndrea Arcangeli 42ba76149fSAndrea Arcangeli /* default scan 8*512 pte (or vmas) every 30 second */ 43ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; 44ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_collapsed; 45ba76149fSAndrea Arcangeli static unsigned int khugepaged_full_scans; 46ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; 47ba76149fSAndrea Arcangeli /* during fragmentation poll the hugepage allocator once every minute */ 48ba76149fSAndrea Arcangeli static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; 49ba76149fSAndrea Arcangeli static struct task_struct *khugepaged_thread __read_mostly; 504a6c1297SKirill A. Shutemov static unsigned long huge_zero_pfn __read_mostly; 51ba76149fSAndrea Arcangeli static DEFINE_MUTEX(khugepaged_mutex); 52ba76149fSAndrea Arcangeli static DEFINE_SPINLOCK(khugepaged_mm_lock); 53ba76149fSAndrea Arcangeli static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); 54ba76149fSAndrea Arcangeli /* 55ba76149fSAndrea Arcangeli * default collapse hugepages if there is at least one pte mapped like 56ba76149fSAndrea Arcangeli * it would have happened if the vma was large enough during page 57ba76149fSAndrea Arcangeli * fault. 58ba76149fSAndrea Arcangeli */ 59ba76149fSAndrea Arcangeli static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; 60ba76149fSAndrea Arcangeli 61ba76149fSAndrea Arcangeli static int khugepaged(void *none); 62ba76149fSAndrea Arcangeli static int mm_slots_hash_init(void); 63ba76149fSAndrea Arcangeli static int khugepaged_slab_init(void); 64ba76149fSAndrea Arcangeli static void khugepaged_slab_free(void); 65ba76149fSAndrea Arcangeli 66ba76149fSAndrea Arcangeli #define MM_SLOTS_HASH_HEADS 1024 67ba76149fSAndrea Arcangeli static struct hlist_head *mm_slots_hash __read_mostly; 68ba76149fSAndrea Arcangeli static struct kmem_cache *mm_slot_cache __read_mostly; 69ba76149fSAndrea Arcangeli 70ba76149fSAndrea Arcangeli /** 71ba76149fSAndrea Arcangeli * struct mm_slot - hash lookup from mm to mm_slot 72ba76149fSAndrea Arcangeli * @hash: hash collision list 73ba76149fSAndrea Arcangeli * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head 74ba76149fSAndrea Arcangeli * @mm: the mm that this information is valid for 75ba76149fSAndrea Arcangeli */ 76ba76149fSAndrea Arcangeli struct mm_slot { 77ba76149fSAndrea Arcangeli struct hlist_node hash; 78ba76149fSAndrea Arcangeli struct list_head mm_node; 79ba76149fSAndrea Arcangeli struct mm_struct *mm; 80ba76149fSAndrea Arcangeli }; 81ba76149fSAndrea Arcangeli 82ba76149fSAndrea Arcangeli /** 83ba76149fSAndrea Arcangeli * struct khugepaged_scan - cursor for scanning 84ba76149fSAndrea Arcangeli * @mm_head: the head of the mm list to scan 85ba76149fSAndrea Arcangeli * @mm_slot: the current mm_slot we are scanning 86ba76149fSAndrea Arcangeli * @address: the next address inside that to be scanned 87ba76149fSAndrea Arcangeli * 88ba76149fSAndrea Arcangeli * There is only the one khugepaged_scan instance of this cursor structure. 89ba76149fSAndrea Arcangeli */ 90ba76149fSAndrea Arcangeli struct khugepaged_scan { 91ba76149fSAndrea Arcangeli struct list_head mm_head; 92ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 93ba76149fSAndrea Arcangeli unsigned long address; 942f1da642SH Hartley Sweeten }; 952f1da642SH Hartley Sweeten static struct khugepaged_scan khugepaged_scan = { 96ba76149fSAndrea Arcangeli .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), 97ba76149fSAndrea Arcangeli }; 98ba76149fSAndrea Arcangeli 99f000565aSAndrea Arcangeli 100f000565aSAndrea Arcangeli static int set_recommended_min_free_kbytes(void) 101f000565aSAndrea Arcangeli { 102f000565aSAndrea Arcangeli struct zone *zone; 103f000565aSAndrea Arcangeli int nr_zones = 0; 104f000565aSAndrea Arcangeli unsigned long recommended_min; 105f000565aSAndrea Arcangeli extern int min_free_kbytes; 106f000565aSAndrea Arcangeli 10717c230afSXiao Guangrong if (!khugepaged_enabled()) 108f000565aSAndrea Arcangeli return 0; 109f000565aSAndrea Arcangeli 110f000565aSAndrea Arcangeli for_each_populated_zone(zone) 111f000565aSAndrea Arcangeli nr_zones++; 112f000565aSAndrea Arcangeli 113f000565aSAndrea Arcangeli /* Make sure at least 2 hugepages are free for MIGRATE_RESERVE */ 114f000565aSAndrea Arcangeli recommended_min = pageblock_nr_pages * nr_zones * 2; 115f000565aSAndrea Arcangeli 116f000565aSAndrea Arcangeli /* 117f000565aSAndrea Arcangeli * Make sure that on average at least two pageblocks are almost free 118f000565aSAndrea Arcangeli * of another type, one for a migratetype to fall back to and a 119f000565aSAndrea Arcangeli * second to avoid subsequent fallbacks of other types There are 3 120f000565aSAndrea Arcangeli * MIGRATE_TYPES we care about. 121f000565aSAndrea Arcangeli */ 122f000565aSAndrea Arcangeli recommended_min += pageblock_nr_pages * nr_zones * 123f000565aSAndrea Arcangeli MIGRATE_PCPTYPES * MIGRATE_PCPTYPES; 124f000565aSAndrea Arcangeli 125f000565aSAndrea Arcangeli /* don't ever allow to reserve more than 5% of the lowmem */ 126f000565aSAndrea Arcangeli recommended_min = min(recommended_min, 127f000565aSAndrea Arcangeli (unsigned long) nr_free_buffer_pages() / 20); 128f000565aSAndrea Arcangeli recommended_min <<= (PAGE_SHIFT-10); 129f000565aSAndrea Arcangeli 130f000565aSAndrea Arcangeli if (recommended_min > min_free_kbytes) 131f000565aSAndrea Arcangeli min_free_kbytes = recommended_min; 132f000565aSAndrea Arcangeli setup_per_zone_wmarks(); 133f000565aSAndrea Arcangeli return 0; 134f000565aSAndrea Arcangeli } 135f000565aSAndrea Arcangeli late_initcall(set_recommended_min_free_kbytes); 136f000565aSAndrea Arcangeli 137ba76149fSAndrea Arcangeli static int start_khugepaged(void) 138ba76149fSAndrea Arcangeli { 139ba76149fSAndrea Arcangeli int err = 0; 140ba76149fSAndrea Arcangeli if (khugepaged_enabled()) { 141ba76149fSAndrea Arcangeli if (!khugepaged_thread) 142ba76149fSAndrea Arcangeli khugepaged_thread = kthread_run(khugepaged, NULL, 143ba76149fSAndrea Arcangeli "khugepaged"); 144ba76149fSAndrea Arcangeli if (unlikely(IS_ERR(khugepaged_thread))) { 145ba76149fSAndrea Arcangeli printk(KERN_ERR 146ba76149fSAndrea Arcangeli "khugepaged: kthread_run(khugepaged) failed\n"); 147ba76149fSAndrea Arcangeli err = PTR_ERR(khugepaged_thread); 148ba76149fSAndrea Arcangeli khugepaged_thread = NULL; 149ba76149fSAndrea Arcangeli } 150911891afSXiao Guangrong 151911891afSXiao Guangrong if (!list_empty(&khugepaged_scan.mm_head)) 152ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 153f000565aSAndrea Arcangeli 154f000565aSAndrea Arcangeli set_recommended_min_free_kbytes(); 155911891afSXiao Guangrong } else if (khugepaged_thread) { 156911891afSXiao Guangrong kthread_stop(khugepaged_thread); 157911891afSXiao Guangrong khugepaged_thread = NULL; 158911891afSXiao Guangrong } 159637e3a27SXiao Guangrong 160ba76149fSAndrea Arcangeli return err; 161ba76149fSAndrea Arcangeli } 16271e3aac0SAndrea Arcangeli 1634a6c1297SKirill A. Shutemov static int __init init_huge_zero_page(void) 1644a6c1297SKirill A. Shutemov { 1654a6c1297SKirill A. Shutemov struct page *hpage; 1664a6c1297SKirill A. Shutemov 1674a6c1297SKirill A. Shutemov hpage = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 1684a6c1297SKirill A. Shutemov HPAGE_PMD_ORDER); 1694a6c1297SKirill A. Shutemov if (!hpage) 1704a6c1297SKirill A. Shutemov return -ENOMEM; 1714a6c1297SKirill A. Shutemov 1724a6c1297SKirill A. Shutemov huge_zero_pfn = page_to_pfn(hpage); 1734a6c1297SKirill A. Shutemov return 0; 1744a6c1297SKirill A. Shutemov } 1754a6c1297SKirill A. Shutemov 1764a6c1297SKirill A. Shutemov static inline bool is_huge_zero_pfn(unsigned long pfn) 1774a6c1297SKirill A. Shutemov { 1784a6c1297SKirill A. Shutemov return pfn == huge_zero_pfn; 1794a6c1297SKirill A. Shutemov } 1804a6c1297SKirill A. Shutemov 1814a6c1297SKirill A. Shutemov static inline bool is_huge_zero_pmd(pmd_t pmd) 1824a6c1297SKirill A. Shutemov { 1834a6c1297SKirill A. Shutemov return is_huge_zero_pfn(pmd_pfn(pmd)); 1844a6c1297SKirill A. Shutemov } 1854a6c1297SKirill A. Shutemov 18671e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 187ba76149fSAndrea Arcangeli 18871e3aac0SAndrea Arcangeli static ssize_t double_flag_show(struct kobject *kobj, 18971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 19071e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 19171e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 19271e3aac0SAndrea Arcangeli { 19371e3aac0SAndrea Arcangeli if (test_bit(enabled, &transparent_hugepage_flags)) { 19471e3aac0SAndrea Arcangeli VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); 19571e3aac0SAndrea Arcangeli return sprintf(buf, "[always] madvise never\n"); 19671e3aac0SAndrea Arcangeli } else if (test_bit(req_madv, &transparent_hugepage_flags)) 19771e3aac0SAndrea Arcangeli return sprintf(buf, "always [madvise] never\n"); 19871e3aac0SAndrea Arcangeli else 19971e3aac0SAndrea Arcangeli return sprintf(buf, "always madvise [never]\n"); 20071e3aac0SAndrea Arcangeli } 20171e3aac0SAndrea Arcangeli static ssize_t double_flag_store(struct kobject *kobj, 20271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 20371e3aac0SAndrea Arcangeli const char *buf, size_t count, 20471e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 20571e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 20671e3aac0SAndrea Arcangeli { 20771e3aac0SAndrea Arcangeli if (!memcmp("always", buf, 20871e3aac0SAndrea Arcangeli min(sizeof("always")-1, count))) { 20971e3aac0SAndrea Arcangeli set_bit(enabled, &transparent_hugepage_flags); 21071e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 21171e3aac0SAndrea Arcangeli } else if (!memcmp("madvise", buf, 21271e3aac0SAndrea Arcangeli min(sizeof("madvise")-1, count))) { 21371e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 21471e3aac0SAndrea Arcangeli set_bit(req_madv, &transparent_hugepage_flags); 21571e3aac0SAndrea Arcangeli } else if (!memcmp("never", buf, 21671e3aac0SAndrea Arcangeli min(sizeof("never")-1, count))) { 21771e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 21871e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 21971e3aac0SAndrea Arcangeli } else 22071e3aac0SAndrea Arcangeli return -EINVAL; 22171e3aac0SAndrea Arcangeli 22271e3aac0SAndrea Arcangeli return count; 22371e3aac0SAndrea Arcangeli } 22471e3aac0SAndrea Arcangeli 22571e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 22671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 22771e3aac0SAndrea Arcangeli { 22871e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 22971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 23071e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 23171e3aac0SAndrea Arcangeli } 23271e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 23371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 23471e3aac0SAndrea Arcangeli const char *buf, size_t count) 23571e3aac0SAndrea Arcangeli { 236ba76149fSAndrea Arcangeli ssize_t ret; 237ba76149fSAndrea Arcangeli 238ba76149fSAndrea Arcangeli ret = double_flag_store(kobj, attr, buf, count, 23971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 24071e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 241ba76149fSAndrea Arcangeli 242ba76149fSAndrea Arcangeli if (ret > 0) { 243911891afSXiao Guangrong int err; 244911891afSXiao Guangrong 245911891afSXiao Guangrong mutex_lock(&khugepaged_mutex); 246911891afSXiao Guangrong err = start_khugepaged(); 247911891afSXiao Guangrong mutex_unlock(&khugepaged_mutex); 248911891afSXiao Guangrong 249ba76149fSAndrea Arcangeli if (err) 250ba76149fSAndrea Arcangeli ret = err; 251ba76149fSAndrea Arcangeli } 252ba76149fSAndrea Arcangeli 253ba76149fSAndrea Arcangeli return ret; 25471e3aac0SAndrea Arcangeli } 25571e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 25671e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 25771e3aac0SAndrea Arcangeli 25871e3aac0SAndrea Arcangeli static ssize_t single_flag_show(struct kobject *kobj, 25971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 26071e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 26171e3aac0SAndrea Arcangeli { 262e27e6151SBen Hutchings return sprintf(buf, "%d\n", 263e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 26471e3aac0SAndrea Arcangeli } 265e27e6151SBen Hutchings 26671e3aac0SAndrea Arcangeli static ssize_t single_flag_store(struct kobject *kobj, 26771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 26871e3aac0SAndrea Arcangeli const char *buf, size_t count, 26971e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 27071e3aac0SAndrea Arcangeli { 271e27e6151SBen Hutchings unsigned long value; 272e27e6151SBen Hutchings int ret; 273e27e6151SBen Hutchings 274e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 275e27e6151SBen Hutchings if (ret < 0) 276e27e6151SBen Hutchings return ret; 277e27e6151SBen Hutchings if (value > 1) 27871e3aac0SAndrea Arcangeli return -EINVAL; 27971e3aac0SAndrea Arcangeli 280e27e6151SBen Hutchings if (value) 281e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 282e27e6151SBen Hutchings else 283e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 284e27e6151SBen Hutchings 28571e3aac0SAndrea Arcangeli return count; 28671e3aac0SAndrea Arcangeli } 28771e3aac0SAndrea Arcangeli 28871e3aac0SAndrea Arcangeli /* 28971e3aac0SAndrea Arcangeli * Currently defrag only disables __GFP_NOWAIT for allocation. A blind 29071e3aac0SAndrea Arcangeli * __GFP_REPEAT is too aggressive, it's never worth swapping tons of 29171e3aac0SAndrea Arcangeli * memory just to allocate one more hugepage. 29271e3aac0SAndrea Arcangeli */ 29371e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 29471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 29571e3aac0SAndrea Arcangeli { 29671e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 29771e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 29871e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 29971e3aac0SAndrea Arcangeli } 30071e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 30171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 30271e3aac0SAndrea Arcangeli const char *buf, size_t count) 30371e3aac0SAndrea Arcangeli { 30471e3aac0SAndrea Arcangeli return double_flag_store(kobj, attr, buf, count, 30571e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 30671e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 30771e3aac0SAndrea Arcangeli } 30871e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 30971e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 31071e3aac0SAndrea Arcangeli 31171e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 31271e3aac0SAndrea Arcangeli static ssize_t debug_cow_show(struct kobject *kobj, 31371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 31471e3aac0SAndrea Arcangeli { 31571e3aac0SAndrea Arcangeli return single_flag_show(kobj, attr, buf, 31671e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 31771e3aac0SAndrea Arcangeli } 31871e3aac0SAndrea Arcangeli static ssize_t debug_cow_store(struct kobject *kobj, 31971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 32071e3aac0SAndrea Arcangeli const char *buf, size_t count) 32171e3aac0SAndrea Arcangeli { 32271e3aac0SAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 32371e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 32471e3aac0SAndrea Arcangeli } 32571e3aac0SAndrea Arcangeli static struct kobj_attribute debug_cow_attr = 32671e3aac0SAndrea Arcangeli __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); 32771e3aac0SAndrea Arcangeli #endif /* CONFIG_DEBUG_VM */ 32871e3aac0SAndrea Arcangeli 32971e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 33071e3aac0SAndrea Arcangeli &enabled_attr.attr, 33171e3aac0SAndrea Arcangeli &defrag_attr.attr, 33271e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 33371e3aac0SAndrea Arcangeli &debug_cow_attr.attr, 33471e3aac0SAndrea Arcangeli #endif 33571e3aac0SAndrea Arcangeli NULL, 33671e3aac0SAndrea Arcangeli }; 33771e3aac0SAndrea Arcangeli 33871e3aac0SAndrea Arcangeli static struct attribute_group hugepage_attr_group = { 33971e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 340ba76149fSAndrea Arcangeli }; 341ba76149fSAndrea Arcangeli 342ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, 343ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 344ba76149fSAndrea Arcangeli char *buf) 345ba76149fSAndrea Arcangeli { 346ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); 347ba76149fSAndrea Arcangeli } 348ba76149fSAndrea Arcangeli 349ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, 350ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 351ba76149fSAndrea Arcangeli const char *buf, size_t count) 352ba76149fSAndrea Arcangeli { 353ba76149fSAndrea Arcangeli unsigned long msecs; 354ba76149fSAndrea Arcangeli int err; 355ba76149fSAndrea Arcangeli 356ba76149fSAndrea Arcangeli err = strict_strtoul(buf, 10, &msecs); 357ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 358ba76149fSAndrea Arcangeli return -EINVAL; 359ba76149fSAndrea Arcangeli 360ba76149fSAndrea Arcangeli khugepaged_scan_sleep_millisecs = msecs; 361ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 362ba76149fSAndrea Arcangeli 363ba76149fSAndrea Arcangeli return count; 364ba76149fSAndrea Arcangeli } 365ba76149fSAndrea Arcangeli static struct kobj_attribute scan_sleep_millisecs_attr = 366ba76149fSAndrea Arcangeli __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, 367ba76149fSAndrea Arcangeli scan_sleep_millisecs_store); 368ba76149fSAndrea Arcangeli 369ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, 370ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 371ba76149fSAndrea Arcangeli char *buf) 372ba76149fSAndrea Arcangeli { 373ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); 374ba76149fSAndrea Arcangeli } 375ba76149fSAndrea Arcangeli 376ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, 377ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 378ba76149fSAndrea Arcangeli const char *buf, size_t count) 379ba76149fSAndrea Arcangeli { 380ba76149fSAndrea Arcangeli unsigned long msecs; 381ba76149fSAndrea Arcangeli int err; 382ba76149fSAndrea Arcangeli 383ba76149fSAndrea Arcangeli err = strict_strtoul(buf, 10, &msecs); 384ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 385ba76149fSAndrea Arcangeli return -EINVAL; 386ba76149fSAndrea Arcangeli 387ba76149fSAndrea Arcangeli khugepaged_alloc_sleep_millisecs = msecs; 388ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 389ba76149fSAndrea Arcangeli 390ba76149fSAndrea Arcangeli return count; 391ba76149fSAndrea Arcangeli } 392ba76149fSAndrea Arcangeli static struct kobj_attribute alloc_sleep_millisecs_attr = 393ba76149fSAndrea Arcangeli __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, 394ba76149fSAndrea Arcangeli alloc_sleep_millisecs_store); 395ba76149fSAndrea Arcangeli 396ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_show(struct kobject *kobj, 397ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 398ba76149fSAndrea Arcangeli char *buf) 399ba76149fSAndrea Arcangeli { 400ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_to_scan); 401ba76149fSAndrea Arcangeli } 402ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_store(struct kobject *kobj, 403ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 404ba76149fSAndrea Arcangeli const char *buf, size_t count) 405ba76149fSAndrea Arcangeli { 406ba76149fSAndrea Arcangeli int err; 407ba76149fSAndrea Arcangeli unsigned long pages; 408ba76149fSAndrea Arcangeli 409ba76149fSAndrea Arcangeli err = strict_strtoul(buf, 10, &pages); 410ba76149fSAndrea Arcangeli if (err || !pages || pages > UINT_MAX) 411ba76149fSAndrea Arcangeli return -EINVAL; 412ba76149fSAndrea Arcangeli 413ba76149fSAndrea Arcangeli khugepaged_pages_to_scan = pages; 414ba76149fSAndrea Arcangeli 415ba76149fSAndrea Arcangeli return count; 416ba76149fSAndrea Arcangeli } 417ba76149fSAndrea Arcangeli static struct kobj_attribute pages_to_scan_attr = 418ba76149fSAndrea Arcangeli __ATTR(pages_to_scan, 0644, pages_to_scan_show, 419ba76149fSAndrea Arcangeli pages_to_scan_store); 420ba76149fSAndrea Arcangeli 421ba76149fSAndrea Arcangeli static ssize_t pages_collapsed_show(struct kobject *kobj, 422ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 423ba76149fSAndrea Arcangeli char *buf) 424ba76149fSAndrea Arcangeli { 425ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_collapsed); 426ba76149fSAndrea Arcangeli } 427ba76149fSAndrea Arcangeli static struct kobj_attribute pages_collapsed_attr = 428ba76149fSAndrea Arcangeli __ATTR_RO(pages_collapsed); 429ba76149fSAndrea Arcangeli 430ba76149fSAndrea Arcangeli static ssize_t full_scans_show(struct kobject *kobj, 431ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 432ba76149fSAndrea Arcangeli char *buf) 433ba76149fSAndrea Arcangeli { 434ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_full_scans); 435ba76149fSAndrea Arcangeli } 436ba76149fSAndrea Arcangeli static struct kobj_attribute full_scans_attr = 437ba76149fSAndrea Arcangeli __ATTR_RO(full_scans); 438ba76149fSAndrea Arcangeli 439ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_show(struct kobject *kobj, 440ba76149fSAndrea Arcangeli struct kobj_attribute *attr, char *buf) 441ba76149fSAndrea Arcangeli { 442ba76149fSAndrea Arcangeli return single_flag_show(kobj, attr, buf, 443ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 444ba76149fSAndrea Arcangeli } 445ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_store(struct kobject *kobj, 446ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 447ba76149fSAndrea Arcangeli const char *buf, size_t count) 448ba76149fSAndrea Arcangeli { 449ba76149fSAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 450ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 451ba76149fSAndrea Arcangeli } 452ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_defrag_attr = 453ba76149fSAndrea Arcangeli __ATTR(defrag, 0644, khugepaged_defrag_show, 454ba76149fSAndrea Arcangeli khugepaged_defrag_store); 455ba76149fSAndrea Arcangeli 456ba76149fSAndrea Arcangeli /* 457ba76149fSAndrea Arcangeli * max_ptes_none controls if khugepaged should collapse hugepages over 458ba76149fSAndrea Arcangeli * any unmapped ptes in turn potentially increasing the memory 459ba76149fSAndrea Arcangeli * footprint of the vmas. When max_ptes_none is 0 khugepaged will not 460ba76149fSAndrea Arcangeli * reduce the available free memory in the system as it 461ba76149fSAndrea Arcangeli * runs. Increasing max_ptes_none will instead potentially reduce the 462ba76149fSAndrea Arcangeli * free memory in the system during the khugepaged scan. 463ba76149fSAndrea Arcangeli */ 464ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, 465ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 466ba76149fSAndrea Arcangeli char *buf) 467ba76149fSAndrea Arcangeli { 468ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_max_ptes_none); 469ba76149fSAndrea Arcangeli } 470ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, 471ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 472ba76149fSAndrea Arcangeli const char *buf, size_t count) 473ba76149fSAndrea Arcangeli { 474ba76149fSAndrea Arcangeli int err; 475ba76149fSAndrea Arcangeli unsigned long max_ptes_none; 476ba76149fSAndrea Arcangeli 477ba76149fSAndrea Arcangeli err = strict_strtoul(buf, 10, &max_ptes_none); 478ba76149fSAndrea Arcangeli if (err || max_ptes_none > HPAGE_PMD_NR-1) 479ba76149fSAndrea Arcangeli return -EINVAL; 480ba76149fSAndrea Arcangeli 481ba76149fSAndrea Arcangeli khugepaged_max_ptes_none = max_ptes_none; 482ba76149fSAndrea Arcangeli 483ba76149fSAndrea Arcangeli return count; 484ba76149fSAndrea Arcangeli } 485ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_max_ptes_none_attr = 486ba76149fSAndrea Arcangeli __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, 487ba76149fSAndrea Arcangeli khugepaged_max_ptes_none_store); 488ba76149fSAndrea Arcangeli 489ba76149fSAndrea Arcangeli static struct attribute *khugepaged_attr[] = { 490ba76149fSAndrea Arcangeli &khugepaged_defrag_attr.attr, 491ba76149fSAndrea Arcangeli &khugepaged_max_ptes_none_attr.attr, 492ba76149fSAndrea Arcangeli &pages_to_scan_attr.attr, 493ba76149fSAndrea Arcangeli &pages_collapsed_attr.attr, 494ba76149fSAndrea Arcangeli &full_scans_attr.attr, 495ba76149fSAndrea Arcangeli &scan_sleep_millisecs_attr.attr, 496ba76149fSAndrea Arcangeli &alloc_sleep_millisecs_attr.attr, 497ba76149fSAndrea Arcangeli NULL, 498ba76149fSAndrea Arcangeli }; 499ba76149fSAndrea Arcangeli 500ba76149fSAndrea Arcangeli static struct attribute_group khugepaged_attr_group = { 501ba76149fSAndrea Arcangeli .attrs = khugepaged_attr, 502ba76149fSAndrea Arcangeli .name = "khugepaged", 50371e3aac0SAndrea Arcangeli }; 504569e5590SShaohua Li 505569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 506569e5590SShaohua Li { 507569e5590SShaohua Li int err; 508569e5590SShaohua Li 509569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 510569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 511569e5590SShaohua Li printk(KERN_ERR "hugepage: failed kobject create\n"); 512569e5590SShaohua Li return -ENOMEM; 513569e5590SShaohua Li } 514569e5590SShaohua Li 515569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 516569e5590SShaohua Li if (err) { 517569e5590SShaohua Li printk(KERN_ERR "hugepage: failed register hugeage group\n"); 518569e5590SShaohua Li goto delete_obj; 519569e5590SShaohua Li } 520569e5590SShaohua Li 521569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 522569e5590SShaohua Li if (err) { 523569e5590SShaohua Li printk(KERN_ERR "hugepage: failed register hugeage group\n"); 524569e5590SShaohua Li goto remove_hp_group; 525569e5590SShaohua Li } 526569e5590SShaohua Li 527569e5590SShaohua Li return 0; 528569e5590SShaohua Li 529569e5590SShaohua Li remove_hp_group: 530569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 531569e5590SShaohua Li delete_obj: 532569e5590SShaohua Li kobject_put(*hugepage_kobj); 533569e5590SShaohua Li return err; 534569e5590SShaohua Li } 535569e5590SShaohua Li 536569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 537569e5590SShaohua Li { 538569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 539569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 540569e5590SShaohua Li kobject_put(hugepage_kobj); 541569e5590SShaohua Li } 542569e5590SShaohua Li #else 543569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 544569e5590SShaohua Li { 545569e5590SShaohua Li return 0; 546569e5590SShaohua Li } 547569e5590SShaohua Li 548569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 549569e5590SShaohua Li { 550569e5590SShaohua Li } 55171e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 55271e3aac0SAndrea Arcangeli 55371e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 55471e3aac0SAndrea Arcangeli { 55571e3aac0SAndrea Arcangeli int err; 556569e5590SShaohua Li struct kobject *hugepage_kobj; 55771e3aac0SAndrea Arcangeli 5584b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 5594b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 560569e5590SShaohua Li return -EINVAL; 5614b7167b9SAndrea Arcangeli } 5624b7167b9SAndrea Arcangeli 563569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 564569e5590SShaohua Li if (err) 565569e5590SShaohua Li return err; 566ba76149fSAndrea Arcangeli 5674a6c1297SKirill A. Shutemov err = init_huge_zero_page(); 5684a6c1297SKirill A. Shutemov if (err) 5694a6c1297SKirill A. Shutemov goto out; 5704a6c1297SKirill A. Shutemov 571ba76149fSAndrea Arcangeli err = khugepaged_slab_init(); 572ba76149fSAndrea Arcangeli if (err) 573ba76149fSAndrea Arcangeli goto out; 574ba76149fSAndrea Arcangeli 575ba76149fSAndrea Arcangeli err = mm_slots_hash_init(); 576ba76149fSAndrea Arcangeli if (err) { 577ba76149fSAndrea Arcangeli khugepaged_slab_free(); 578ba76149fSAndrea Arcangeli goto out; 579ba76149fSAndrea Arcangeli } 580ba76149fSAndrea Arcangeli 58197562cd2SRik van Riel /* 58297562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 58397562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 58497562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 58597562cd2SRik van Riel */ 58697562cd2SRik van Riel if (totalram_pages < (512 << (20 - PAGE_SHIFT))) 58797562cd2SRik van Riel transparent_hugepage_flags = 0; 58897562cd2SRik van Riel 589ba76149fSAndrea Arcangeli start_khugepaged(); 590ba76149fSAndrea Arcangeli 591569e5590SShaohua Li return 0; 592ba76149fSAndrea Arcangeli out: 5934a6c1297SKirill A. Shutemov if (huge_zero_pfn) 5944a6c1297SKirill A. Shutemov __free_page(pfn_to_page(huge_zero_pfn)); 595569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 596ba76149fSAndrea Arcangeli return err; 59771e3aac0SAndrea Arcangeli } 59871e3aac0SAndrea Arcangeli module_init(hugepage_init) 59971e3aac0SAndrea Arcangeli 60071e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 60171e3aac0SAndrea Arcangeli { 60271e3aac0SAndrea Arcangeli int ret = 0; 60371e3aac0SAndrea Arcangeli if (!str) 60471e3aac0SAndrea Arcangeli goto out; 60571e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 60671e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 60771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 60871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 60971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 61071e3aac0SAndrea Arcangeli ret = 1; 61171e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 61271e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 61371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 61471e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 61571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 61671e3aac0SAndrea Arcangeli ret = 1; 61771e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 61871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 61971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 62071e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 62171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 62271e3aac0SAndrea Arcangeli ret = 1; 62371e3aac0SAndrea Arcangeli } 62471e3aac0SAndrea Arcangeli out: 62571e3aac0SAndrea Arcangeli if (!ret) 62671e3aac0SAndrea Arcangeli printk(KERN_WARNING 62771e3aac0SAndrea Arcangeli "transparent_hugepage= cannot parse, ignored\n"); 62871e3aac0SAndrea Arcangeli return ret; 62971e3aac0SAndrea Arcangeli } 63071e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 63171e3aac0SAndrea Arcangeli 63271e3aac0SAndrea Arcangeli static inline pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 63371e3aac0SAndrea Arcangeli { 63471e3aac0SAndrea Arcangeli if (likely(vma->vm_flags & VM_WRITE)) 63571e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 63671e3aac0SAndrea Arcangeli return pmd; 63771e3aac0SAndrea Arcangeli } 63871e3aac0SAndrea Arcangeli 639b3092b3bSBob Liu static inline pmd_t mk_huge_pmd(struct page *page, struct vm_area_struct *vma) 640b3092b3bSBob Liu { 641b3092b3bSBob Liu pmd_t entry; 642b3092b3bSBob Liu entry = mk_pmd(page, vma->vm_page_prot); 643b3092b3bSBob Liu entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 644b3092b3bSBob Liu entry = pmd_mkhuge(entry); 645b3092b3bSBob Liu return entry; 646b3092b3bSBob Liu } 647b3092b3bSBob Liu 64871e3aac0SAndrea Arcangeli static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, 64971e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 65071e3aac0SAndrea Arcangeli unsigned long haddr, pmd_t *pmd, 65171e3aac0SAndrea Arcangeli struct page *page) 65271e3aac0SAndrea Arcangeli { 65371e3aac0SAndrea Arcangeli pgtable_t pgtable; 65471e3aac0SAndrea Arcangeli 65571e3aac0SAndrea Arcangeli VM_BUG_ON(!PageCompound(page)); 65671e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(mm, haddr); 657edad9d2cSDavid Rientjes if (unlikely(!pgtable)) 65871e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 65971e3aac0SAndrea Arcangeli 66071e3aac0SAndrea Arcangeli clear_huge_page(page, haddr, HPAGE_PMD_NR); 66171e3aac0SAndrea Arcangeli __SetPageUptodate(page); 66271e3aac0SAndrea Arcangeli 66371e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 66471e3aac0SAndrea Arcangeli if (unlikely(!pmd_none(*pmd))) { 66571e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 666b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(page); 66771e3aac0SAndrea Arcangeli put_page(page); 66871e3aac0SAndrea Arcangeli pte_free(mm, pgtable); 66971e3aac0SAndrea Arcangeli } else { 67071e3aac0SAndrea Arcangeli pmd_t entry; 671b3092b3bSBob Liu entry = mk_huge_pmd(page, vma); 67271e3aac0SAndrea Arcangeli /* 67371e3aac0SAndrea Arcangeli * The spinlocking to take the lru_lock inside 67471e3aac0SAndrea Arcangeli * page_add_new_anon_rmap() acts as a full memory 67571e3aac0SAndrea Arcangeli * barrier to be sure clear_huge_page writes become 67671e3aac0SAndrea Arcangeli * visible after the set_pmd_at() write. 67771e3aac0SAndrea Arcangeli */ 67871e3aac0SAndrea Arcangeli page_add_new_anon_rmap(page, vma, haddr); 67971e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 680e3ebcf64SGerald Schaefer pgtable_trans_huge_deposit(mm, pgtable); 68171e3aac0SAndrea Arcangeli add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 6821c641e84SAndrea Arcangeli mm->nr_ptes++; 68371e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 68471e3aac0SAndrea Arcangeli } 68571e3aac0SAndrea Arcangeli 686aa2e878eSDavid Rientjes return 0; 68771e3aac0SAndrea Arcangeli } 68871e3aac0SAndrea Arcangeli 689cc5d462fSAndi Kleen static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) 6900bbbc0b3SAndrea Arcangeli { 691cc5d462fSAndi Kleen return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; 6920bbbc0b3SAndrea Arcangeli } 6930bbbc0b3SAndrea Arcangeli 6940bbbc0b3SAndrea Arcangeli static inline struct page *alloc_hugepage_vma(int defrag, 6950bbbc0b3SAndrea Arcangeli struct vm_area_struct *vma, 696cc5d462fSAndi Kleen unsigned long haddr, int nd, 697cc5d462fSAndi Kleen gfp_t extra_gfp) 6980bbbc0b3SAndrea Arcangeli { 699cc5d462fSAndi Kleen return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), 7005c4b4be3SAndi Kleen HPAGE_PMD_ORDER, vma, haddr, nd); 7010bbbc0b3SAndrea Arcangeli } 7020bbbc0b3SAndrea Arcangeli 7030bbbc0b3SAndrea Arcangeli #ifndef CONFIG_NUMA 70471e3aac0SAndrea Arcangeli static inline struct page *alloc_hugepage(int defrag) 70571e3aac0SAndrea Arcangeli { 706cc5d462fSAndi Kleen return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), 70771e3aac0SAndrea Arcangeli HPAGE_PMD_ORDER); 70871e3aac0SAndrea Arcangeli } 7090bbbc0b3SAndrea Arcangeli #endif 71071e3aac0SAndrea Arcangeli 71171e3aac0SAndrea Arcangeli int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 71271e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, 71371e3aac0SAndrea Arcangeli unsigned int flags) 71471e3aac0SAndrea Arcangeli { 71571e3aac0SAndrea Arcangeli struct page *page; 71671e3aac0SAndrea Arcangeli unsigned long haddr = address & HPAGE_PMD_MASK; 71771e3aac0SAndrea Arcangeli pte_t *pte; 71871e3aac0SAndrea Arcangeli 71971e3aac0SAndrea Arcangeli if (haddr >= vma->vm_start && haddr + HPAGE_PMD_SIZE <= vma->vm_end) { 72071e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 72171e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 722ba76149fSAndrea Arcangeli if (unlikely(khugepaged_enter(vma))) 723ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 7240bbbc0b3SAndrea Arcangeli page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), 725cc5d462fSAndi Kleen vma, haddr, numa_node_id(), 0); 72681ab4201SAndi Kleen if (unlikely(!page)) { 72781ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 72871e3aac0SAndrea Arcangeli goto out; 72981ab4201SAndi Kleen } 73081ab4201SAndi Kleen count_vm_event(THP_FAULT_ALLOC); 731b9bbfbe3SAndrea Arcangeli if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { 732b9bbfbe3SAndrea Arcangeli put_page(page); 733b9bbfbe3SAndrea Arcangeli goto out; 734b9bbfbe3SAndrea Arcangeli } 735edad9d2cSDavid Rientjes if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, 736edad9d2cSDavid Rientjes page))) { 737edad9d2cSDavid Rientjes mem_cgroup_uncharge_page(page); 738edad9d2cSDavid Rientjes put_page(page); 739edad9d2cSDavid Rientjes goto out; 740edad9d2cSDavid Rientjes } 74171e3aac0SAndrea Arcangeli 742edad9d2cSDavid Rientjes return 0; 74371e3aac0SAndrea Arcangeli } 74471e3aac0SAndrea Arcangeli out: 74571e3aac0SAndrea Arcangeli /* 74671e3aac0SAndrea Arcangeli * Use __pte_alloc instead of pte_alloc_map, because we can't 74771e3aac0SAndrea Arcangeli * run pte_offset_map on the pmd, if an huge pmd could 74871e3aac0SAndrea Arcangeli * materialize from under us from a different thread. 74971e3aac0SAndrea Arcangeli */ 75071e3aac0SAndrea Arcangeli if (unlikely(__pte_alloc(mm, vma, pmd, address))) 75171e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 75271e3aac0SAndrea Arcangeli /* if an huge pmd materialized from under us just retry later */ 75371e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_huge(*pmd))) 75471e3aac0SAndrea Arcangeli return 0; 75571e3aac0SAndrea Arcangeli /* 75671e3aac0SAndrea Arcangeli * A regular pmd is established and it can't morph into a huge pmd 75771e3aac0SAndrea Arcangeli * from under us anymore at this point because we hold the mmap_sem 75871e3aac0SAndrea Arcangeli * read mode and khugepaged takes it in write mode. So now it's 75971e3aac0SAndrea Arcangeli * safe to run pte_offset_map(). 76071e3aac0SAndrea Arcangeli */ 76171e3aac0SAndrea Arcangeli pte = pte_offset_map(pmd, address); 76271e3aac0SAndrea Arcangeli return handle_pte_fault(mm, vma, address, pte, pmd, flags); 76371e3aac0SAndrea Arcangeli } 76471e3aac0SAndrea Arcangeli 76571e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 76671e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 76771e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 76871e3aac0SAndrea Arcangeli { 76971e3aac0SAndrea Arcangeli struct page *src_page; 77071e3aac0SAndrea Arcangeli pmd_t pmd; 77171e3aac0SAndrea Arcangeli pgtable_t pgtable; 77271e3aac0SAndrea Arcangeli int ret; 77371e3aac0SAndrea Arcangeli 77471e3aac0SAndrea Arcangeli ret = -ENOMEM; 77571e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(dst_mm, addr); 77671e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 77771e3aac0SAndrea Arcangeli goto out; 77871e3aac0SAndrea Arcangeli 77971e3aac0SAndrea Arcangeli spin_lock(&dst_mm->page_table_lock); 78071e3aac0SAndrea Arcangeli spin_lock_nested(&src_mm->page_table_lock, SINGLE_DEPTH_NESTING); 78171e3aac0SAndrea Arcangeli 78271e3aac0SAndrea Arcangeli ret = -EAGAIN; 78371e3aac0SAndrea Arcangeli pmd = *src_pmd; 78471e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(pmd))) { 78571e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 78671e3aac0SAndrea Arcangeli goto out_unlock; 78771e3aac0SAndrea Arcangeli } 78871e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_splitting(pmd))) { 78971e3aac0SAndrea Arcangeli /* split huge page running from under us */ 79071e3aac0SAndrea Arcangeli spin_unlock(&src_mm->page_table_lock); 79171e3aac0SAndrea Arcangeli spin_unlock(&dst_mm->page_table_lock); 79271e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 79371e3aac0SAndrea Arcangeli 79471e3aac0SAndrea Arcangeli wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ 79571e3aac0SAndrea Arcangeli goto out; 79671e3aac0SAndrea Arcangeli } 79771e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 79871e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(src_page)); 79971e3aac0SAndrea Arcangeli get_page(src_page); 80071e3aac0SAndrea Arcangeli page_dup_rmap(src_page); 80171e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 80271e3aac0SAndrea Arcangeli 80371e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 80471e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 80571e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 806e3ebcf64SGerald Schaefer pgtable_trans_huge_deposit(dst_mm, pgtable); 8071c641e84SAndrea Arcangeli dst_mm->nr_ptes++; 80871e3aac0SAndrea Arcangeli 80971e3aac0SAndrea Arcangeli ret = 0; 81071e3aac0SAndrea Arcangeli out_unlock: 81171e3aac0SAndrea Arcangeli spin_unlock(&src_mm->page_table_lock); 81271e3aac0SAndrea Arcangeli spin_unlock(&dst_mm->page_table_lock); 81371e3aac0SAndrea Arcangeli out: 81471e3aac0SAndrea Arcangeli return ret; 81571e3aac0SAndrea Arcangeli } 81671e3aac0SAndrea Arcangeli 817a1dd450bSWill Deacon void huge_pmd_set_accessed(struct mm_struct *mm, 818a1dd450bSWill Deacon struct vm_area_struct *vma, 819a1dd450bSWill Deacon unsigned long address, 820a1dd450bSWill Deacon pmd_t *pmd, pmd_t orig_pmd, 821a1dd450bSWill Deacon int dirty) 822a1dd450bSWill Deacon { 823a1dd450bSWill Deacon pmd_t entry; 824a1dd450bSWill Deacon unsigned long haddr; 825a1dd450bSWill Deacon 826a1dd450bSWill Deacon spin_lock(&mm->page_table_lock); 827a1dd450bSWill Deacon if (unlikely(!pmd_same(*pmd, orig_pmd))) 828a1dd450bSWill Deacon goto unlock; 829a1dd450bSWill Deacon 830a1dd450bSWill Deacon entry = pmd_mkyoung(orig_pmd); 831a1dd450bSWill Deacon haddr = address & HPAGE_PMD_MASK; 832a1dd450bSWill Deacon if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) 833a1dd450bSWill Deacon update_mmu_cache_pmd(vma, address, pmd); 834a1dd450bSWill Deacon 835a1dd450bSWill Deacon unlock: 836a1dd450bSWill Deacon spin_unlock(&mm->page_table_lock); 837a1dd450bSWill Deacon } 838a1dd450bSWill Deacon 83971e3aac0SAndrea Arcangeli static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, 84071e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 84171e3aac0SAndrea Arcangeli unsigned long address, 84271e3aac0SAndrea Arcangeli pmd_t *pmd, pmd_t orig_pmd, 84371e3aac0SAndrea Arcangeli struct page *page, 84471e3aac0SAndrea Arcangeli unsigned long haddr) 84571e3aac0SAndrea Arcangeli { 84671e3aac0SAndrea Arcangeli pgtable_t pgtable; 84771e3aac0SAndrea Arcangeli pmd_t _pmd; 84871e3aac0SAndrea Arcangeli int ret = 0, i; 84971e3aac0SAndrea Arcangeli struct page **pages; 8502ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 8512ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 85271e3aac0SAndrea Arcangeli 85371e3aac0SAndrea Arcangeli pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, 85471e3aac0SAndrea Arcangeli GFP_KERNEL); 85571e3aac0SAndrea Arcangeli if (unlikely(!pages)) { 85671e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 85771e3aac0SAndrea Arcangeli goto out; 85871e3aac0SAndrea Arcangeli } 85971e3aac0SAndrea Arcangeli 86071e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 861cc5d462fSAndi Kleen pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | 862cc5d462fSAndi Kleen __GFP_OTHER_NODE, 86319ee151eSAndi Kleen vma, address, page_to_nid(page)); 864b9bbfbe3SAndrea Arcangeli if (unlikely(!pages[i] || 865b9bbfbe3SAndrea Arcangeli mem_cgroup_newpage_charge(pages[i], mm, 866b9bbfbe3SAndrea Arcangeli GFP_KERNEL))) { 867b9bbfbe3SAndrea Arcangeli if (pages[i]) 86871e3aac0SAndrea Arcangeli put_page(pages[i]); 869b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_start(); 870b9bbfbe3SAndrea Arcangeli while (--i >= 0) { 871b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(pages[i]); 872b9bbfbe3SAndrea Arcangeli put_page(pages[i]); 873b9bbfbe3SAndrea Arcangeli } 874b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_end(); 87571e3aac0SAndrea Arcangeli kfree(pages); 87671e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 87771e3aac0SAndrea Arcangeli goto out; 87871e3aac0SAndrea Arcangeli } 87971e3aac0SAndrea Arcangeli } 88071e3aac0SAndrea Arcangeli 88171e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 88271e3aac0SAndrea Arcangeli copy_user_highpage(pages[i], page + i, 8830089e485SHillf Danton haddr + PAGE_SIZE * i, vma); 88471e3aac0SAndrea Arcangeli __SetPageUptodate(pages[i]); 88571e3aac0SAndrea Arcangeli cond_resched(); 88671e3aac0SAndrea Arcangeli } 88771e3aac0SAndrea Arcangeli 8882ec74c3eSSagi Grimberg mmun_start = haddr; 8892ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 8902ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 8912ec74c3eSSagi Grimberg 89271e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 89371e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 89471e3aac0SAndrea Arcangeli goto out_free_pages; 89571e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 89671e3aac0SAndrea Arcangeli 8972ec74c3eSSagi Grimberg pmdp_clear_flush(vma, haddr, pmd); 89871e3aac0SAndrea Arcangeli /* leave pmd empty until pte is filled */ 89971e3aac0SAndrea Arcangeli 900e3ebcf64SGerald Schaefer pgtable = pgtable_trans_huge_withdraw(mm); 90171e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 90271e3aac0SAndrea Arcangeli 90371e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 90471e3aac0SAndrea Arcangeli pte_t *pte, entry; 90571e3aac0SAndrea Arcangeli entry = mk_pte(pages[i], vma->vm_page_prot); 90671e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 90771e3aac0SAndrea Arcangeli page_add_new_anon_rmap(pages[i], vma, haddr); 90871e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 90971e3aac0SAndrea Arcangeli VM_BUG_ON(!pte_none(*pte)); 91071e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 91171e3aac0SAndrea Arcangeli pte_unmap(pte); 91271e3aac0SAndrea Arcangeli } 91371e3aac0SAndrea Arcangeli kfree(pages); 91471e3aac0SAndrea Arcangeli 91571e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 91671e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 91771e3aac0SAndrea Arcangeli page_remove_rmap(page); 91871e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 91971e3aac0SAndrea Arcangeli 9202ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 9212ec74c3eSSagi Grimberg 92271e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 92371e3aac0SAndrea Arcangeli put_page(page); 92471e3aac0SAndrea Arcangeli 92571e3aac0SAndrea Arcangeli out: 92671e3aac0SAndrea Arcangeli return ret; 92771e3aac0SAndrea Arcangeli 92871e3aac0SAndrea Arcangeli out_free_pages: 92971e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 9302ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 931b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_start(); 932b9bbfbe3SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 933b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(pages[i]); 93471e3aac0SAndrea Arcangeli put_page(pages[i]); 935b9bbfbe3SAndrea Arcangeli } 936b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_end(); 93771e3aac0SAndrea Arcangeli kfree(pages); 93871e3aac0SAndrea Arcangeli goto out; 93971e3aac0SAndrea Arcangeli } 94071e3aac0SAndrea Arcangeli 94171e3aac0SAndrea Arcangeli int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 94271e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, pmd_t orig_pmd) 94371e3aac0SAndrea Arcangeli { 94471e3aac0SAndrea Arcangeli int ret = 0; 94571e3aac0SAndrea Arcangeli struct page *page, *new_page; 94671e3aac0SAndrea Arcangeli unsigned long haddr; 9472ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 9482ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 94971e3aac0SAndrea Arcangeli 95071e3aac0SAndrea Arcangeli VM_BUG_ON(!vma->anon_vma); 95171e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 95271e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 95371e3aac0SAndrea Arcangeli goto out_unlock; 95471e3aac0SAndrea Arcangeli 95571e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 95671e3aac0SAndrea Arcangeli VM_BUG_ON(!PageCompound(page) || !PageHead(page)); 95771e3aac0SAndrea Arcangeli haddr = address & HPAGE_PMD_MASK; 95871e3aac0SAndrea Arcangeli if (page_mapcount(page) == 1) { 95971e3aac0SAndrea Arcangeli pmd_t entry; 96071e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 96171e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 96271e3aac0SAndrea Arcangeli if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) 963b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 96471e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 96571e3aac0SAndrea Arcangeli goto out_unlock; 96671e3aac0SAndrea Arcangeli } 96771e3aac0SAndrea Arcangeli get_page(page); 96871e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 96971e3aac0SAndrea Arcangeli 97071e3aac0SAndrea Arcangeli if (transparent_hugepage_enabled(vma) && 97171e3aac0SAndrea Arcangeli !transparent_hugepage_debug_cow()) 9720bbbc0b3SAndrea Arcangeli new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), 973cc5d462fSAndi Kleen vma, haddr, numa_node_id(), 0); 97471e3aac0SAndrea Arcangeli else 97571e3aac0SAndrea Arcangeli new_page = NULL; 97671e3aac0SAndrea Arcangeli 97771e3aac0SAndrea Arcangeli if (unlikely(!new_page)) { 97881ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 97971e3aac0SAndrea Arcangeli ret = do_huge_pmd_wp_page_fallback(mm, vma, address, 98071e3aac0SAndrea Arcangeli pmd, orig_pmd, page, haddr); 9811f1d06c3SDavid Rientjes if (ret & VM_FAULT_OOM) 9821f1d06c3SDavid Rientjes split_huge_page(page); 98371e3aac0SAndrea Arcangeli put_page(page); 98471e3aac0SAndrea Arcangeli goto out; 98571e3aac0SAndrea Arcangeli } 98681ab4201SAndi Kleen count_vm_event(THP_FAULT_ALLOC); 98771e3aac0SAndrea Arcangeli 988b9bbfbe3SAndrea Arcangeli if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { 989b9bbfbe3SAndrea Arcangeli put_page(new_page); 9901f1d06c3SDavid Rientjes split_huge_page(page); 991b9bbfbe3SAndrea Arcangeli put_page(page); 992b9bbfbe3SAndrea Arcangeli ret |= VM_FAULT_OOM; 993b9bbfbe3SAndrea Arcangeli goto out; 994b9bbfbe3SAndrea Arcangeli } 995b9bbfbe3SAndrea Arcangeli 99671e3aac0SAndrea Arcangeli copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); 99771e3aac0SAndrea Arcangeli __SetPageUptodate(new_page); 99871e3aac0SAndrea Arcangeli 9992ec74c3eSSagi Grimberg mmun_start = haddr; 10002ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 10012ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 10022ec74c3eSSagi Grimberg 100371e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 100471e3aac0SAndrea Arcangeli put_page(page); 1005b9bbfbe3SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) { 10066f60b69dSDavid Rientjes spin_unlock(&mm->page_table_lock); 1007b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(new_page); 100871e3aac0SAndrea Arcangeli put_page(new_page); 10092ec74c3eSSagi Grimberg goto out_mn; 1010b9bbfbe3SAndrea Arcangeli } else { 101171e3aac0SAndrea Arcangeli pmd_t entry; 101271e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 1013b3092b3bSBob Liu entry = mk_huge_pmd(new_page, vma); 10142ec74c3eSSagi Grimberg pmdp_clear_flush(vma, haddr, pmd); 101571e3aac0SAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, haddr); 101671e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 1017b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 101871e3aac0SAndrea Arcangeli page_remove_rmap(page); 101971e3aac0SAndrea Arcangeli put_page(page); 102071e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 102171e3aac0SAndrea Arcangeli } 10222ec74c3eSSagi Grimberg spin_unlock(&mm->page_table_lock); 10232ec74c3eSSagi Grimberg out_mn: 10242ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 10252ec74c3eSSagi Grimberg out: 10262ec74c3eSSagi Grimberg return ret; 102771e3aac0SAndrea Arcangeli out_unlock: 102871e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 102971e3aac0SAndrea Arcangeli return ret; 103071e3aac0SAndrea Arcangeli } 103171e3aac0SAndrea Arcangeli 1032b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 103371e3aac0SAndrea Arcangeli unsigned long addr, 103471e3aac0SAndrea Arcangeli pmd_t *pmd, 103571e3aac0SAndrea Arcangeli unsigned int flags) 103671e3aac0SAndrea Arcangeli { 1037b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 103871e3aac0SAndrea Arcangeli struct page *page = NULL; 103971e3aac0SAndrea Arcangeli 104071e3aac0SAndrea Arcangeli assert_spin_locked(&mm->page_table_lock); 104171e3aac0SAndrea Arcangeli 104271e3aac0SAndrea Arcangeli if (flags & FOLL_WRITE && !pmd_write(*pmd)) 104371e3aac0SAndrea Arcangeli goto out; 104471e3aac0SAndrea Arcangeli 104571e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 104671e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 104771e3aac0SAndrea Arcangeli if (flags & FOLL_TOUCH) { 104871e3aac0SAndrea Arcangeli pmd_t _pmd; 104971e3aac0SAndrea Arcangeli /* 105071e3aac0SAndrea Arcangeli * We should set the dirty bit only for FOLL_WRITE but 105171e3aac0SAndrea Arcangeli * for now the dirty bit in the pmd is meaningless. 105271e3aac0SAndrea Arcangeli * And if the dirty bit will become meaningful and 105371e3aac0SAndrea Arcangeli * we'll only set it with FOLL_WRITE, an atomic 105471e3aac0SAndrea Arcangeli * set_bit will be required on the pmd to set the 105571e3aac0SAndrea Arcangeli * young bit, instead of the current set_pmd_at. 105671e3aac0SAndrea Arcangeli */ 105771e3aac0SAndrea Arcangeli _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); 105871e3aac0SAndrea Arcangeli set_pmd_at(mm, addr & HPAGE_PMD_MASK, pmd, _pmd); 105971e3aac0SAndrea Arcangeli } 1060b676b293SDavid Rientjes if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { 1061b676b293SDavid Rientjes if (page->mapping && trylock_page(page)) { 1062b676b293SDavid Rientjes lru_add_drain(); 1063b676b293SDavid Rientjes if (page->mapping) 1064b676b293SDavid Rientjes mlock_vma_page(page); 1065b676b293SDavid Rientjes unlock_page(page); 1066b676b293SDavid Rientjes } 1067b676b293SDavid Rientjes } 106871e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 106971e3aac0SAndrea Arcangeli VM_BUG_ON(!PageCompound(page)); 107071e3aac0SAndrea Arcangeli if (flags & FOLL_GET) 107170b50f94SAndrea Arcangeli get_page_foll(page); 107271e3aac0SAndrea Arcangeli 107371e3aac0SAndrea Arcangeli out: 107471e3aac0SAndrea Arcangeli return page; 107571e3aac0SAndrea Arcangeli } 107671e3aac0SAndrea Arcangeli 107771e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1078f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 107971e3aac0SAndrea Arcangeli { 108071e3aac0SAndrea Arcangeli int ret = 0; 108171e3aac0SAndrea Arcangeli 1082025c5b24SNaoya Horiguchi if (__pmd_trans_huge_lock(pmd, vma) == 1) { 108371e3aac0SAndrea Arcangeli struct page *page; 108471e3aac0SAndrea Arcangeli pgtable_t pgtable; 1085f5c8ad47SDavid Miller pmd_t orig_pmd; 1086e3ebcf64SGerald Schaefer pgtable = pgtable_trans_huge_withdraw(tlb->mm); 1087f5c8ad47SDavid Miller orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); 1088f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1089*479f0abbSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) { 1090*479f0abbSKirill A. Shutemov tlb->mm->nr_ptes--; 1091*479f0abbSKirill A. Shutemov spin_unlock(&tlb->mm->page_table_lock); 1092*479f0abbSKirill A. Shutemov } else { 1093*479f0abbSKirill A. Shutemov page = pmd_page(orig_pmd); 109471e3aac0SAndrea Arcangeli page_remove_rmap(page); 109571e3aac0SAndrea Arcangeli VM_BUG_ON(page_mapcount(page) < 0); 109671e3aac0SAndrea Arcangeli add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 109771e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 10981c641e84SAndrea Arcangeli tlb->mm->nr_ptes--; 109971e3aac0SAndrea Arcangeli spin_unlock(&tlb->mm->page_table_lock); 110071e3aac0SAndrea Arcangeli tlb_remove_page(tlb, page); 1101*479f0abbSKirill A. Shutemov } 110271e3aac0SAndrea Arcangeli pte_free(tlb->mm, pgtable); 110371e3aac0SAndrea Arcangeli ret = 1; 110471e3aac0SAndrea Arcangeli } 110571e3aac0SAndrea Arcangeli return ret; 110671e3aac0SAndrea Arcangeli } 110771e3aac0SAndrea Arcangeli 11080ca1634dSJohannes Weiner int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 11090ca1634dSJohannes Weiner unsigned long addr, unsigned long end, 11100ca1634dSJohannes Weiner unsigned char *vec) 11110ca1634dSJohannes Weiner { 11120ca1634dSJohannes Weiner int ret = 0; 11130ca1634dSJohannes Weiner 1114025c5b24SNaoya Horiguchi if (__pmd_trans_huge_lock(pmd, vma) == 1) { 11150ca1634dSJohannes Weiner /* 11160ca1634dSJohannes Weiner * All logical pages in the range are present 11170ca1634dSJohannes Weiner * if backed by a huge page. 11180ca1634dSJohannes Weiner */ 11190ca1634dSJohannes Weiner spin_unlock(&vma->vm_mm->page_table_lock); 1120025c5b24SNaoya Horiguchi memset(vec, 1, (end - addr) >> PAGE_SHIFT); 1121025c5b24SNaoya Horiguchi ret = 1; 1122025c5b24SNaoya Horiguchi } 11230ca1634dSJohannes Weiner 11240ca1634dSJohannes Weiner return ret; 11250ca1634dSJohannes Weiner } 11260ca1634dSJohannes Weiner 112737a1c49aSAndrea Arcangeli int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, 112837a1c49aSAndrea Arcangeli unsigned long old_addr, 112937a1c49aSAndrea Arcangeli unsigned long new_addr, unsigned long old_end, 113037a1c49aSAndrea Arcangeli pmd_t *old_pmd, pmd_t *new_pmd) 113137a1c49aSAndrea Arcangeli { 113237a1c49aSAndrea Arcangeli int ret = 0; 113337a1c49aSAndrea Arcangeli pmd_t pmd; 113437a1c49aSAndrea Arcangeli 113537a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 113637a1c49aSAndrea Arcangeli 113737a1c49aSAndrea Arcangeli if ((old_addr & ~HPAGE_PMD_MASK) || 113837a1c49aSAndrea Arcangeli (new_addr & ~HPAGE_PMD_MASK) || 113937a1c49aSAndrea Arcangeli old_end - old_addr < HPAGE_PMD_SIZE || 114037a1c49aSAndrea Arcangeli (new_vma->vm_flags & VM_NOHUGEPAGE)) 114137a1c49aSAndrea Arcangeli goto out; 114237a1c49aSAndrea Arcangeli 114337a1c49aSAndrea Arcangeli /* 114437a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 114537a1c49aSAndrea Arcangeli * should have release it. 114637a1c49aSAndrea Arcangeli */ 114737a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 114837a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 114937a1c49aSAndrea Arcangeli goto out; 115037a1c49aSAndrea Arcangeli } 115137a1c49aSAndrea Arcangeli 1152025c5b24SNaoya Horiguchi ret = __pmd_trans_huge_lock(old_pmd, vma); 1153025c5b24SNaoya Horiguchi if (ret == 1) { 115437a1c49aSAndrea Arcangeli pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); 115537a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 115637a1c49aSAndrea Arcangeli set_pmd_at(mm, new_addr, new_pmd, pmd); 115737a1c49aSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 115837a1c49aSAndrea Arcangeli } 115937a1c49aSAndrea Arcangeli out: 116037a1c49aSAndrea Arcangeli return ret; 116137a1c49aSAndrea Arcangeli } 116237a1c49aSAndrea Arcangeli 1163cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 1164cd7548abSJohannes Weiner unsigned long addr, pgprot_t newprot) 1165cd7548abSJohannes Weiner { 1166cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1167cd7548abSJohannes Weiner int ret = 0; 1168cd7548abSJohannes Weiner 1169025c5b24SNaoya Horiguchi if (__pmd_trans_huge_lock(pmd, vma) == 1) { 1170cd7548abSJohannes Weiner pmd_t entry; 1171cd7548abSJohannes Weiner entry = pmdp_get_and_clear(mm, addr, pmd); 1172cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 1173cd7548abSJohannes Weiner set_pmd_at(mm, addr, pmd, entry); 1174cd7548abSJohannes Weiner spin_unlock(&vma->vm_mm->page_table_lock); 1175cd7548abSJohannes Weiner ret = 1; 1176cd7548abSJohannes Weiner } 1177cd7548abSJohannes Weiner 1178cd7548abSJohannes Weiner return ret; 1179cd7548abSJohannes Weiner } 1180cd7548abSJohannes Weiner 1181025c5b24SNaoya Horiguchi /* 1182025c5b24SNaoya Horiguchi * Returns 1 if a given pmd maps a stable (not under splitting) thp. 1183025c5b24SNaoya Horiguchi * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. 1184025c5b24SNaoya Horiguchi * 1185025c5b24SNaoya Horiguchi * Note that if it returns 1, this routine returns without unlocking page 1186025c5b24SNaoya Horiguchi * table locks. So callers must unlock them. 1187025c5b24SNaoya Horiguchi */ 1188025c5b24SNaoya Horiguchi int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1189025c5b24SNaoya Horiguchi { 1190025c5b24SNaoya Horiguchi spin_lock(&vma->vm_mm->page_table_lock); 1191025c5b24SNaoya Horiguchi if (likely(pmd_trans_huge(*pmd))) { 1192025c5b24SNaoya Horiguchi if (unlikely(pmd_trans_splitting(*pmd))) { 1193025c5b24SNaoya Horiguchi spin_unlock(&vma->vm_mm->page_table_lock); 1194025c5b24SNaoya Horiguchi wait_split_huge_page(vma->anon_vma, pmd); 1195025c5b24SNaoya Horiguchi return -1; 1196025c5b24SNaoya Horiguchi } else { 1197025c5b24SNaoya Horiguchi /* Thp mapped by 'pmd' is stable, so we can 1198025c5b24SNaoya Horiguchi * handle it as it is. */ 1199025c5b24SNaoya Horiguchi return 1; 1200025c5b24SNaoya Horiguchi } 1201025c5b24SNaoya Horiguchi } 1202025c5b24SNaoya Horiguchi spin_unlock(&vma->vm_mm->page_table_lock); 1203025c5b24SNaoya Horiguchi return 0; 1204025c5b24SNaoya Horiguchi } 1205025c5b24SNaoya Horiguchi 120671e3aac0SAndrea Arcangeli pmd_t *page_check_address_pmd(struct page *page, 120771e3aac0SAndrea Arcangeli struct mm_struct *mm, 120871e3aac0SAndrea Arcangeli unsigned long address, 120971e3aac0SAndrea Arcangeli enum page_check_address_pmd_flag flag) 121071e3aac0SAndrea Arcangeli { 121171e3aac0SAndrea Arcangeli pmd_t *pmd, *ret = NULL; 121271e3aac0SAndrea Arcangeli 121371e3aac0SAndrea Arcangeli if (address & ~HPAGE_PMD_MASK) 121471e3aac0SAndrea Arcangeli goto out; 121571e3aac0SAndrea Arcangeli 12166219049aSBob Liu pmd = mm_find_pmd(mm, address); 12176219049aSBob Liu if (!pmd) 121871e3aac0SAndrea Arcangeli goto out; 121971e3aac0SAndrea Arcangeli if (pmd_none(*pmd)) 122071e3aac0SAndrea Arcangeli goto out; 122171e3aac0SAndrea Arcangeli if (pmd_page(*pmd) != page) 122271e3aac0SAndrea Arcangeli goto out; 122394fcc585SAndrea Arcangeli /* 122494fcc585SAndrea Arcangeli * split_vma() may create temporary aliased mappings. There is 122594fcc585SAndrea Arcangeli * no risk as long as all huge pmd are found and have their 122694fcc585SAndrea Arcangeli * splitting bit set before __split_huge_page_refcount 122794fcc585SAndrea Arcangeli * runs. Finding the same huge pmd more than once during the 122894fcc585SAndrea Arcangeli * same rmap walk is not a problem. 122994fcc585SAndrea Arcangeli */ 123094fcc585SAndrea Arcangeli if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && 123194fcc585SAndrea Arcangeli pmd_trans_splitting(*pmd)) 123294fcc585SAndrea Arcangeli goto out; 123371e3aac0SAndrea Arcangeli if (pmd_trans_huge(*pmd)) { 123471e3aac0SAndrea Arcangeli VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && 123571e3aac0SAndrea Arcangeli !pmd_trans_splitting(*pmd)); 123671e3aac0SAndrea Arcangeli ret = pmd; 123771e3aac0SAndrea Arcangeli } 123871e3aac0SAndrea Arcangeli out: 123971e3aac0SAndrea Arcangeli return ret; 124071e3aac0SAndrea Arcangeli } 124171e3aac0SAndrea Arcangeli 124271e3aac0SAndrea Arcangeli static int __split_huge_page_splitting(struct page *page, 124371e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 124471e3aac0SAndrea Arcangeli unsigned long address) 124571e3aac0SAndrea Arcangeli { 124671e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 124771e3aac0SAndrea Arcangeli pmd_t *pmd; 124871e3aac0SAndrea Arcangeli int ret = 0; 12492ec74c3eSSagi Grimberg /* For mmu_notifiers */ 12502ec74c3eSSagi Grimberg const unsigned long mmun_start = address; 12512ec74c3eSSagi Grimberg const unsigned long mmun_end = address + HPAGE_PMD_SIZE; 125271e3aac0SAndrea Arcangeli 12532ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 125471e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 125571e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 125671e3aac0SAndrea Arcangeli PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG); 125771e3aac0SAndrea Arcangeli if (pmd) { 125871e3aac0SAndrea Arcangeli /* 125971e3aac0SAndrea Arcangeli * We can't temporarily set the pmd to null in order 126071e3aac0SAndrea Arcangeli * to split it, the pmd must remain marked huge at all 126171e3aac0SAndrea Arcangeli * times or the VM won't take the pmd_trans_huge paths 12622b575eb6SPeter Zijlstra * and it won't wait on the anon_vma->root->mutex to 126371e3aac0SAndrea Arcangeli * serialize against split_huge_page*. 126471e3aac0SAndrea Arcangeli */ 12652ec74c3eSSagi Grimberg pmdp_splitting_flush(vma, address, pmd); 126671e3aac0SAndrea Arcangeli ret = 1; 126771e3aac0SAndrea Arcangeli } 126871e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 12692ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 127071e3aac0SAndrea Arcangeli 127171e3aac0SAndrea Arcangeli return ret; 127271e3aac0SAndrea Arcangeli } 127371e3aac0SAndrea Arcangeli 127471e3aac0SAndrea Arcangeli static void __split_huge_page_refcount(struct page *page) 127571e3aac0SAndrea Arcangeli { 127671e3aac0SAndrea Arcangeli int i; 127771e3aac0SAndrea Arcangeli struct zone *zone = page_zone(page); 1278fa9add64SHugh Dickins struct lruvec *lruvec; 127970b50f94SAndrea Arcangeli int tail_count = 0; 128071e3aac0SAndrea Arcangeli 128171e3aac0SAndrea Arcangeli /* prevent PageLRU to go away from under us, and freeze lru stats */ 128271e3aac0SAndrea Arcangeli spin_lock_irq(&zone->lru_lock); 1283fa9add64SHugh Dickins lruvec = mem_cgroup_page_lruvec(page, zone); 1284fa9add64SHugh Dickins 128571e3aac0SAndrea Arcangeli compound_lock(page); 1286e94c8a9cSKAMEZAWA Hiroyuki /* complete memcg works before add pages to LRU */ 1287e94c8a9cSKAMEZAWA Hiroyuki mem_cgroup_split_huge_fixup(page); 128871e3aac0SAndrea Arcangeli 128945676885SShaohua Li for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { 129071e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 129171e3aac0SAndrea Arcangeli 129270b50f94SAndrea Arcangeli /* tail_page->_mapcount cannot change */ 129370b50f94SAndrea Arcangeli BUG_ON(page_mapcount(page_tail) < 0); 129470b50f94SAndrea Arcangeli tail_count += page_mapcount(page_tail); 129570b50f94SAndrea Arcangeli /* check for overflow */ 129670b50f94SAndrea Arcangeli BUG_ON(tail_count < 0); 129770b50f94SAndrea Arcangeli BUG_ON(atomic_read(&page_tail->_count) != 0); 129870b50f94SAndrea Arcangeli /* 129970b50f94SAndrea Arcangeli * tail_page->_count is zero and not changing from 130070b50f94SAndrea Arcangeli * under us. But get_page_unless_zero() may be running 130170b50f94SAndrea Arcangeli * from under us on the tail_page. If we used 130270b50f94SAndrea Arcangeli * atomic_set() below instead of atomic_add(), we 130370b50f94SAndrea Arcangeli * would then run atomic_set() concurrently with 130470b50f94SAndrea Arcangeli * get_page_unless_zero(), and atomic_set() is 130570b50f94SAndrea Arcangeli * implemented in C not using locked ops. spin_unlock 130670b50f94SAndrea Arcangeli * on x86 sometime uses locked ops because of PPro 130770b50f94SAndrea Arcangeli * errata 66, 92, so unless somebody can guarantee 130870b50f94SAndrea Arcangeli * atomic_set() here would be safe on all archs (and 130970b50f94SAndrea Arcangeli * not only on x86), it's safer to use atomic_add(). 131070b50f94SAndrea Arcangeli */ 131170b50f94SAndrea Arcangeli atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, 131270b50f94SAndrea Arcangeli &page_tail->_count); 131371e3aac0SAndrea Arcangeli 131471e3aac0SAndrea Arcangeli /* after clearing PageTail the gup refcount can be released */ 131571e3aac0SAndrea Arcangeli smp_mb(); 131671e3aac0SAndrea Arcangeli 1317a6d30dddSJin Dongming /* 1318a6d30dddSJin Dongming * retain hwpoison flag of the poisoned tail page: 1319a6d30dddSJin Dongming * fix for the unsuitable process killed on Guest Machine(KVM) 1320a6d30dddSJin Dongming * by the memory-failure. 1321a6d30dddSJin Dongming */ 1322a6d30dddSJin Dongming page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; 132371e3aac0SAndrea Arcangeli page_tail->flags |= (page->flags & 132471e3aac0SAndrea Arcangeli ((1L << PG_referenced) | 132571e3aac0SAndrea Arcangeli (1L << PG_swapbacked) | 132671e3aac0SAndrea Arcangeli (1L << PG_mlocked) | 132771e3aac0SAndrea Arcangeli (1L << PG_uptodate))); 132871e3aac0SAndrea Arcangeli page_tail->flags |= (1L << PG_dirty); 132971e3aac0SAndrea Arcangeli 133070b50f94SAndrea Arcangeli /* clear PageTail before overwriting first_page */ 133171e3aac0SAndrea Arcangeli smp_wmb(); 133271e3aac0SAndrea Arcangeli 133371e3aac0SAndrea Arcangeli /* 133471e3aac0SAndrea Arcangeli * __split_huge_page_splitting() already set the 133571e3aac0SAndrea Arcangeli * splitting bit in all pmd that could map this 133671e3aac0SAndrea Arcangeli * hugepage, that will ensure no CPU can alter the 133771e3aac0SAndrea Arcangeli * mapcount on the head page. The mapcount is only 133871e3aac0SAndrea Arcangeli * accounted in the head page and it has to be 133971e3aac0SAndrea Arcangeli * transferred to all tail pages in the below code. So 134071e3aac0SAndrea Arcangeli * for this code to be safe, the split the mapcount 134171e3aac0SAndrea Arcangeli * can't change. But that doesn't mean userland can't 134271e3aac0SAndrea Arcangeli * keep changing and reading the page contents while 134371e3aac0SAndrea Arcangeli * we transfer the mapcount, so the pmd splitting 134471e3aac0SAndrea Arcangeli * status is achieved setting a reserved bit in the 134571e3aac0SAndrea Arcangeli * pmd, not by clearing the present bit. 134671e3aac0SAndrea Arcangeli */ 134771e3aac0SAndrea Arcangeli page_tail->_mapcount = page->_mapcount; 134871e3aac0SAndrea Arcangeli 134971e3aac0SAndrea Arcangeli BUG_ON(page_tail->mapping); 135071e3aac0SAndrea Arcangeli page_tail->mapping = page->mapping; 135171e3aac0SAndrea Arcangeli 135245676885SShaohua Li page_tail->index = page->index + i; 135371e3aac0SAndrea Arcangeli 135471e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page_tail)); 135571e3aac0SAndrea Arcangeli BUG_ON(!PageUptodate(page_tail)); 135671e3aac0SAndrea Arcangeli BUG_ON(!PageDirty(page_tail)); 135771e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page_tail)); 135871e3aac0SAndrea Arcangeli 1359fa9add64SHugh Dickins lru_add_page_tail(page, page_tail, lruvec); 136071e3aac0SAndrea Arcangeli } 136170b50f94SAndrea Arcangeli atomic_sub(tail_count, &page->_count); 136270b50f94SAndrea Arcangeli BUG_ON(atomic_read(&page->_count) <= 0); 136371e3aac0SAndrea Arcangeli 1364fa9add64SHugh Dickins __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); 136579134171SAndrea Arcangeli __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR); 136679134171SAndrea Arcangeli 136771e3aac0SAndrea Arcangeli ClearPageCompound(page); 136871e3aac0SAndrea Arcangeli compound_unlock(page); 136971e3aac0SAndrea Arcangeli spin_unlock_irq(&zone->lru_lock); 137071e3aac0SAndrea Arcangeli 137171e3aac0SAndrea Arcangeli for (i = 1; i < HPAGE_PMD_NR; i++) { 137271e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 137371e3aac0SAndrea Arcangeli BUG_ON(page_count(page_tail) <= 0); 137471e3aac0SAndrea Arcangeli /* 137571e3aac0SAndrea Arcangeli * Tail pages may be freed if there wasn't any mapping 137671e3aac0SAndrea Arcangeli * like if add_to_swap() is running on a lru page that 137771e3aac0SAndrea Arcangeli * had its mapping zapped. And freeing these pages 137871e3aac0SAndrea Arcangeli * requires taking the lru_lock so we do the put_page 137971e3aac0SAndrea Arcangeli * of the tail pages after the split is complete. 138071e3aac0SAndrea Arcangeli */ 138171e3aac0SAndrea Arcangeli put_page(page_tail); 138271e3aac0SAndrea Arcangeli } 138371e3aac0SAndrea Arcangeli 138471e3aac0SAndrea Arcangeli /* 138571e3aac0SAndrea Arcangeli * Only the head page (now become a regular page) is required 138671e3aac0SAndrea Arcangeli * to be pinned by the caller. 138771e3aac0SAndrea Arcangeli */ 138871e3aac0SAndrea Arcangeli BUG_ON(page_count(page) <= 0); 138971e3aac0SAndrea Arcangeli } 139071e3aac0SAndrea Arcangeli 139171e3aac0SAndrea Arcangeli static int __split_huge_page_map(struct page *page, 139271e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 139371e3aac0SAndrea Arcangeli unsigned long address) 139471e3aac0SAndrea Arcangeli { 139571e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 139671e3aac0SAndrea Arcangeli pmd_t *pmd, _pmd; 139771e3aac0SAndrea Arcangeli int ret = 0, i; 139871e3aac0SAndrea Arcangeli pgtable_t pgtable; 139971e3aac0SAndrea Arcangeli unsigned long haddr; 140071e3aac0SAndrea Arcangeli 140171e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 140271e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 140371e3aac0SAndrea Arcangeli PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); 140471e3aac0SAndrea Arcangeli if (pmd) { 1405e3ebcf64SGerald Schaefer pgtable = pgtable_trans_huge_withdraw(mm); 140671e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 140771e3aac0SAndrea Arcangeli 1408e3ebcf64SGerald Schaefer haddr = address; 1409e3ebcf64SGerald Schaefer for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 141071e3aac0SAndrea Arcangeli pte_t *pte, entry; 141171e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page+i)); 141271e3aac0SAndrea Arcangeli entry = mk_pte(page + i, vma->vm_page_prot); 141371e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 141471e3aac0SAndrea Arcangeli if (!pmd_write(*pmd)) 141571e3aac0SAndrea Arcangeli entry = pte_wrprotect(entry); 141671e3aac0SAndrea Arcangeli else 141771e3aac0SAndrea Arcangeli BUG_ON(page_mapcount(page) != 1); 141871e3aac0SAndrea Arcangeli if (!pmd_young(*pmd)) 141971e3aac0SAndrea Arcangeli entry = pte_mkold(entry); 142071e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 142171e3aac0SAndrea Arcangeli BUG_ON(!pte_none(*pte)); 142271e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 142371e3aac0SAndrea Arcangeli pte_unmap(pte); 142471e3aac0SAndrea Arcangeli } 142571e3aac0SAndrea Arcangeli 142671e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 142771e3aac0SAndrea Arcangeli /* 142871e3aac0SAndrea Arcangeli * Up to this point the pmd is present and huge and 142971e3aac0SAndrea Arcangeli * userland has the whole access to the hugepage 143071e3aac0SAndrea Arcangeli * during the split (which happens in place). If we 143171e3aac0SAndrea Arcangeli * overwrite the pmd with the not-huge version 143271e3aac0SAndrea Arcangeli * pointing to the pte here (which of course we could 143371e3aac0SAndrea Arcangeli * if all CPUs were bug free), userland could trigger 143471e3aac0SAndrea Arcangeli * a small page size TLB miss on the small sized TLB 143571e3aac0SAndrea Arcangeli * while the hugepage TLB entry is still established 143671e3aac0SAndrea Arcangeli * in the huge TLB. Some CPU doesn't like that. See 143771e3aac0SAndrea Arcangeli * http://support.amd.com/us/Processor_TechDocs/41322.pdf, 143871e3aac0SAndrea Arcangeli * Erratum 383 on page 93. Intel should be safe but is 143971e3aac0SAndrea Arcangeli * also warns that it's only safe if the permission 144071e3aac0SAndrea Arcangeli * and cache attributes of the two entries loaded in 144171e3aac0SAndrea Arcangeli * the two TLB is identical (which should be the case 144271e3aac0SAndrea Arcangeli * here). But it is generally safer to never allow 144371e3aac0SAndrea Arcangeli * small and huge TLB entries for the same virtual 144471e3aac0SAndrea Arcangeli * address to be loaded simultaneously. So instead of 144571e3aac0SAndrea Arcangeli * doing "pmd_populate(); flush_tlb_range();" we first 144671e3aac0SAndrea Arcangeli * mark the current pmd notpresent (atomically because 144771e3aac0SAndrea Arcangeli * here the pmd_trans_huge and pmd_trans_splitting 144871e3aac0SAndrea Arcangeli * must remain set at all times on the pmd until the 144971e3aac0SAndrea Arcangeli * split is complete for this pmd), then we flush the 145071e3aac0SAndrea Arcangeli * SMP TLB and finally we write the non-huge version 145171e3aac0SAndrea Arcangeli * of the pmd entry with pmd_populate. 145271e3aac0SAndrea Arcangeli */ 145346dcde73SGerald Schaefer pmdp_invalidate(vma, address, pmd); 145471e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 145571e3aac0SAndrea Arcangeli ret = 1; 145671e3aac0SAndrea Arcangeli } 145771e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 145871e3aac0SAndrea Arcangeli 145971e3aac0SAndrea Arcangeli return ret; 146071e3aac0SAndrea Arcangeli } 146171e3aac0SAndrea Arcangeli 14622b575eb6SPeter Zijlstra /* must be called with anon_vma->root->mutex hold */ 146371e3aac0SAndrea Arcangeli static void __split_huge_page(struct page *page, 146471e3aac0SAndrea Arcangeli struct anon_vma *anon_vma) 146571e3aac0SAndrea Arcangeli { 146671e3aac0SAndrea Arcangeli int mapcount, mapcount2; 1467bf181b9fSMichel Lespinasse pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); 146871e3aac0SAndrea Arcangeli struct anon_vma_chain *avc; 146971e3aac0SAndrea Arcangeli 147071e3aac0SAndrea Arcangeli BUG_ON(!PageHead(page)); 147171e3aac0SAndrea Arcangeli BUG_ON(PageTail(page)); 147271e3aac0SAndrea Arcangeli 147371e3aac0SAndrea Arcangeli mapcount = 0; 1474bf181b9fSMichel Lespinasse anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { 147571e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 147671e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 147771e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 147871e3aac0SAndrea Arcangeli mapcount += __split_huge_page_splitting(page, vma, addr); 147971e3aac0SAndrea Arcangeli } 148005759d38SAndrea Arcangeli /* 148105759d38SAndrea Arcangeli * It is critical that new vmas are added to the tail of the 148205759d38SAndrea Arcangeli * anon_vma list. This guarantes that if copy_huge_pmd() runs 148305759d38SAndrea Arcangeli * and establishes a child pmd before 148405759d38SAndrea Arcangeli * __split_huge_page_splitting() freezes the parent pmd (so if 148505759d38SAndrea Arcangeli * we fail to prevent copy_huge_pmd() from running until the 148605759d38SAndrea Arcangeli * whole __split_huge_page() is complete), we will still see 148705759d38SAndrea Arcangeli * the newly established pmd of the child later during the 148805759d38SAndrea Arcangeli * walk, to be able to set it as pmd_trans_splitting too. 148905759d38SAndrea Arcangeli */ 149005759d38SAndrea Arcangeli if (mapcount != page_mapcount(page)) 149105759d38SAndrea Arcangeli printk(KERN_ERR "mapcount %d page_mapcount %d\n", 149205759d38SAndrea Arcangeli mapcount, page_mapcount(page)); 149371e3aac0SAndrea Arcangeli BUG_ON(mapcount != page_mapcount(page)); 149471e3aac0SAndrea Arcangeli 149571e3aac0SAndrea Arcangeli __split_huge_page_refcount(page); 149671e3aac0SAndrea Arcangeli 149771e3aac0SAndrea Arcangeli mapcount2 = 0; 1498bf181b9fSMichel Lespinasse anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { 149971e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 150071e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 150171e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 150271e3aac0SAndrea Arcangeli mapcount2 += __split_huge_page_map(page, vma, addr); 150371e3aac0SAndrea Arcangeli } 150405759d38SAndrea Arcangeli if (mapcount != mapcount2) 150505759d38SAndrea Arcangeli printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", 150605759d38SAndrea Arcangeli mapcount, mapcount2, page_mapcount(page)); 150771e3aac0SAndrea Arcangeli BUG_ON(mapcount != mapcount2); 150871e3aac0SAndrea Arcangeli } 150971e3aac0SAndrea Arcangeli 151071e3aac0SAndrea Arcangeli int split_huge_page(struct page *page) 151171e3aac0SAndrea Arcangeli { 151271e3aac0SAndrea Arcangeli struct anon_vma *anon_vma; 151371e3aac0SAndrea Arcangeli int ret = 1; 151471e3aac0SAndrea Arcangeli 151571e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page)); 151671e3aac0SAndrea Arcangeli anon_vma = page_lock_anon_vma(page); 151771e3aac0SAndrea Arcangeli if (!anon_vma) 151871e3aac0SAndrea Arcangeli goto out; 151971e3aac0SAndrea Arcangeli ret = 0; 152071e3aac0SAndrea Arcangeli if (!PageCompound(page)) 152171e3aac0SAndrea Arcangeli goto out_unlock; 152271e3aac0SAndrea Arcangeli 152371e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page)); 152471e3aac0SAndrea Arcangeli __split_huge_page(page, anon_vma); 152581ab4201SAndi Kleen count_vm_event(THP_SPLIT); 152671e3aac0SAndrea Arcangeli 152771e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page)); 152871e3aac0SAndrea Arcangeli out_unlock: 152971e3aac0SAndrea Arcangeli page_unlock_anon_vma(anon_vma); 153071e3aac0SAndrea Arcangeli out: 153171e3aac0SAndrea Arcangeli return ret; 153271e3aac0SAndrea Arcangeli } 153371e3aac0SAndrea Arcangeli 15344b6e1e37SKonstantin Khlebnikov #define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE) 153578f11a25SAndrea Arcangeli 153660ab3244SAndrea Arcangeli int hugepage_madvise(struct vm_area_struct *vma, 153760ab3244SAndrea Arcangeli unsigned long *vm_flags, int advice) 15380af4e98bSAndrea Arcangeli { 15398e72033fSGerald Schaefer struct mm_struct *mm = vma->vm_mm; 15408e72033fSGerald Schaefer 1541a664b2d8SAndrea Arcangeli switch (advice) { 1542a664b2d8SAndrea Arcangeli case MADV_HUGEPAGE: 15430af4e98bSAndrea Arcangeli /* 15440af4e98bSAndrea Arcangeli * Be somewhat over-protective like KSM for now! 15450af4e98bSAndrea Arcangeli */ 154678f11a25SAndrea Arcangeli if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) 15470af4e98bSAndrea Arcangeli return -EINVAL; 15488e72033fSGerald Schaefer if (mm->def_flags & VM_NOHUGEPAGE) 15498e72033fSGerald Schaefer return -EINVAL; 1550a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_NOHUGEPAGE; 15510af4e98bSAndrea Arcangeli *vm_flags |= VM_HUGEPAGE; 155260ab3244SAndrea Arcangeli /* 155360ab3244SAndrea Arcangeli * If the vma become good for khugepaged to scan, 155460ab3244SAndrea Arcangeli * register it here without waiting a page fault that 155560ab3244SAndrea Arcangeli * may not happen any time soon. 155660ab3244SAndrea Arcangeli */ 155760ab3244SAndrea Arcangeli if (unlikely(khugepaged_enter_vma_merge(vma))) 155860ab3244SAndrea Arcangeli return -ENOMEM; 1559a664b2d8SAndrea Arcangeli break; 1560a664b2d8SAndrea Arcangeli case MADV_NOHUGEPAGE: 1561a664b2d8SAndrea Arcangeli /* 1562a664b2d8SAndrea Arcangeli * Be somewhat over-protective like KSM for now! 1563a664b2d8SAndrea Arcangeli */ 156478f11a25SAndrea Arcangeli if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) 1565a664b2d8SAndrea Arcangeli return -EINVAL; 1566a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_HUGEPAGE; 1567a664b2d8SAndrea Arcangeli *vm_flags |= VM_NOHUGEPAGE; 156860ab3244SAndrea Arcangeli /* 156960ab3244SAndrea Arcangeli * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning 157060ab3244SAndrea Arcangeli * this vma even if we leave the mm registered in khugepaged if 157160ab3244SAndrea Arcangeli * it got registered before VM_NOHUGEPAGE was set. 157260ab3244SAndrea Arcangeli */ 1573a664b2d8SAndrea Arcangeli break; 1574a664b2d8SAndrea Arcangeli } 15750af4e98bSAndrea Arcangeli 15760af4e98bSAndrea Arcangeli return 0; 15770af4e98bSAndrea Arcangeli } 15780af4e98bSAndrea Arcangeli 1579ba76149fSAndrea Arcangeli static int __init khugepaged_slab_init(void) 1580ba76149fSAndrea Arcangeli { 1581ba76149fSAndrea Arcangeli mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", 1582ba76149fSAndrea Arcangeli sizeof(struct mm_slot), 1583ba76149fSAndrea Arcangeli __alignof__(struct mm_slot), 0, NULL); 1584ba76149fSAndrea Arcangeli if (!mm_slot_cache) 1585ba76149fSAndrea Arcangeli return -ENOMEM; 1586ba76149fSAndrea Arcangeli 1587ba76149fSAndrea Arcangeli return 0; 1588ba76149fSAndrea Arcangeli } 1589ba76149fSAndrea Arcangeli 1590ba76149fSAndrea Arcangeli static void __init khugepaged_slab_free(void) 1591ba76149fSAndrea Arcangeli { 1592ba76149fSAndrea Arcangeli kmem_cache_destroy(mm_slot_cache); 1593ba76149fSAndrea Arcangeli mm_slot_cache = NULL; 1594ba76149fSAndrea Arcangeli } 1595ba76149fSAndrea Arcangeli 1596ba76149fSAndrea Arcangeli static inline struct mm_slot *alloc_mm_slot(void) 1597ba76149fSAndrea Arcangeli { 1598ba76149fSAndrea Arcangeli if (!mm_slot_cache) /* initialization failed */ 1599ba76149fSAndrea Arcangeli return NULL; 1600ba76149fSAndrea Arcangeli return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); 1601ba76149fSAndrea Arcangeli } 1602ba76149fSAndrea Arcangeli 1603ba76149fSAndrea Arcangeli static inline void free_mm_slot(struct mm_slot *mm_slot) 1604ba76149fSAndrea Arcangeli { 1605ba76149fSAndrea Arcangeli kmem_cache_free(mm_slot_cache, mm_slot); 1606ba76149fSAndrea Arcangeli } 1607ba76149fSAndrea Arcangeli 1608ba76149fSAndrea Arcangeli static int __init mm_slots_hash_init(void) 1609ba76149fSAndrea Arcangeli { 1610ba76149fSAndrea Arcangeli mm_slots_hash = kzalloc(MM_SLOTS_HASH_HEADS * sizeof(struct hlist_head), 1611ba76149fSAndrea Arcangeli GFP_KERNEL); 1612ba76149fSAndrea Arcangeli if (!mm_slots_hash) 1613ba76149fSAndrea Arcangeli return -ENOMEM; 1614ba76149fSAndrea Arcangeli return 0; 1615ba76149fSAndrea Arcangeli } 1616ba76149fSAndrea Arcangeli 1617ba76149fSAndrea Arcangeli #if 0 1618ba76149fSAndrea Arcangeli static void __init mm_slots_hash_free(void) 1619ba76149fSAndrea Arcangeli { 1620ba76149fSAndrea Arcangeli kfree(mm_slots_hash); 1621ba76149fSAndrea Arcangeli mm_slots_hash = NULL; 1622ba76149fSAndrea Arcangeli } 1623ba76149fSAndrea Arcangeli #endif 1624ba76149fSAndrea Arcangeli 1625ba76149fSAndrea Arcangeli static struct mm_slot *get_mm_slot(struct mm_struct *mm) 1626ba76149fSAndrea Arcangeli { 1627ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1628ba76149fSAndrea Arcangeli struct hlist_head *bucket; 1629ba76149fSAndrea Arcangeli struct hlist_node *node; 1630ba76149fSAndrea Arcangeli 1631ba76149fSAndrea Arcangeli bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) 1632ba76149fSAndrea Arcangeli % MM_SLOTS_HASH_HEADS]; 1633ba76149fSAndrea Arcangeli hlist_for_each_entry(mm_slot, node, bucket, hash) { 1634ba76149fSAndrea Arcangeli if (mm == mm_slot->mm) 1635ba76149fSAndrea Arcangeli return mm_slot; 1636ba76149fSAndrea Arcangeli } 1637ba76149fSAndrea Arcangeli return NULL; 1638ba76149fSAndrea Arcangeli } 1639ba76149fSAndrea Arcangeli 1640ba76149fSAndrea Arcangeli static void insert_to_mm_slots_hash(struct mm_struct *mm, 1641ba76149fSAndrea Arcangeli struct mm_slot *mm_slot) 1642ba76149fSAndrea Arcangeli { 1643ba76149fSAndrea Arcangeli struct hlist_head *bucket; 1644ba76149fSAndrea Arcangeli 1645ba76149fSAndrea Arcangeli bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) 1646ba76149fSAndrea Arcangeli % MM_SLOTS_HASH_HEADS]; 1647ba76149fSAndrea Arcangeli mm_slot->mm = mm; 1648ba76149fSAndrea Arcangeli hlist_add_head(&mm_slot->hash, bucket); 1649ba76149fSAndrea Arcangeli } 1650ba76149fSAndrea Arcangeli 1651ba76149fSAndrea Arcangeli static inline int khugepaged_test_exit(struct mm_struct *mm) 1652ba76149fSAndrea Arcangeli { 1653ba76149fSAndrea Arcangeli return atomic_read(&mm->mm_users) == 0; 1654ba76149fSAndrea Arcangeli } 1655ba76149fSAndrea Arcangeli 1656ba76149fSAndrea Arcangeli int __khugepaged_enter(struct mm_struct *mm) 1657ba76149fSAndrea Arcangeli { 1658ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1659ba76149fSAndrea Arcangeli int wakeup; 1660ba76149fSAndrea Arcangeli 1661ba76149fSAndrea Arcangeli mm_slot = alloc_mm_slot(); 1662ba76149fSAndrea Arcangeli if (!mm_slot) 1663ba76149fSAndrea Arcangeli return -ENOMEM; 1664ba76149fSAndrea Arcangeli 1665ba76149fSAndrea Arcangeli /* __khugepaged_exit() must not run from under us */ 1666ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_test_exit(mm)); 1667ba76149fSAndrea Arcangeli if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { 1668ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 1669ba76149fSAndrea Arcangeli return 0; 1670ba76149fSAndrea Arcangeli } 1671ba76149fSAndrea Arcangeli 1672ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 1673ba76149fSAndrea Arcangeli insert_to_mm_slots_hash(mm, mm_slot); 1674ba76149fSAndrea Arcangeli /* 1675ba76149fSAndrea Arcangeli * Insert just behind the scanning cursor, to let the area settle 1676ba76149fSAndrea Arcangeli * down a little. 1677ba76149fSAndrea Arcangeli */ 1678ba76149fSAndrea Arcangeli wakeup = list_empty(&khugepaged_scan.mm_head); 1679ba76149fSAndrea Arcangeli list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); 1680ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 1681ba76149fSAndrea Arcangeli 1682ba76149fSAndrea Arcangeli atomic_inc(&mm->mm_count); 1683ba76149fSAndrea Arcangeli if (wakeup) 1684ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 1685ba76149fSAndrea Arcangeli 1686ba76149fSAndrea Arcangeli return 0; 1687ba76149fSAndrea Arcangeli } 1688ba76149fSAndrea Arcangeli 1689ba76149fSAndrea Arcangeli int khugepaged_enter_vma_merge(struct vm_area_struct *vma) 1690ba76149fSAndrea Arcangeli { 1691ba76149fSAndrea Arcangeli unsigned long hstart, hend; 1692ba76149fSAndrea Arcangeli if (!vma->anon_vma) 1693ba76149fSAndrea Arcangeli /* 1694ba76149fSAndrea Arcangeli * Not yet faulted in so we will register later in the 1695ba76149fSAndrea Arcangeli * page fault if needed. 1696ba76149fSAndrea Arcangeli */ 1697ba76149fSAndrea Arcangeli return 0; 169878f11a25SAndrea Arcangeli if (vma->vm_ops) 1699ba76149fSAndrea Arcangeli /* khugepaged not yet working on file or special mappings */ 1700ba76149fSAndrea Arcangeli return 0; 1701b3b9c293SKonstantin Khlebnikov VM_BUG_ON(vma->vm_flags & VM_NO_THP); 1702ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 1703ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 1704ba76149fSAndrea Arcangeli if (hstart < hend) 1705ba76149fSAndrea Arcangeli return khugepaged_enter(vma); 1706ba76149fSAndrea Arcangeli return 0; 1707ba76149fSAndrea Arcangeli } 1708ba76149fSAndrea Arcangeli 1709ba76149fSAndrea Arcangeli void __khugepaged_exit(struct mm_struct *mm) 1710ba76149fSAndrea Arcangeli { 1711ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1712ba76149fSAndrea Arcangeli int free = 0; 1713ba76149fSAndrea Arcangeli 1714ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 1715ba76149fSAndrea Arcangeli mm_slot = get_mm_slot(mm); 1716ba76149fSAndrea Arcangeli if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { 1717ba76149fSAndrea Arcangeli hlist_del(&mm_slot->hash); 1718ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 1719ba76149fSAndrea Arcangeli free = 1; 1720ba76149fSAndrea Arcangeli } 1721d788e80aSChris Wright spin_unlock(&khugepaged_mm_lock); 1722ba76149fSAndrea Arcangeli 1723ba76149fSAndrea Arcangeli if (free) { 1724ba76149fSAndrea Arcangeli clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 1725ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 1726ba76149fSAndrea Arcangeli mmdrop(mm); 1727ba76149fSAndrea Arcangeli } else if (mm_slot) { 1728ba76149fSAndrea Arcangeli /* 1729ba76149fSAndrea Arcangeli * This is required to serialize against 1730ba76149fSAndrea Arcangeli * khugepaged_test_exit() (which is guaranteed to run 1731ba76149fSAndrea Arcangeli * under mmap sem read mode). Stop here (after we 1732ba76149fSAndrea Arcangeli * return all pagetables will be destroyed) until 1733ba76149fSAndrea Arcangeli * khugepaged has finished working on the pagetables 1734ba76149fSAndrea Arcangeli * under the mmap_sem. 1735ba76149fSAndrea Arcangeli */ 1736ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 1737ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 1738d788e80aSChris Wright } 1739ba76149fSAndrea Arcangeli } 1740ba76149fSAndrea Arcangeli 1741ba76149fSAndrea Arcangeli static void release_pte_page(struct page *page) 1742ba76149fSAndrea Arcangeli { 1743ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 1744ba76149fSAndrea Arcangeli dec_zone_page_state(page, NR_ISOLATED_ANON + 0); 1745ba76149fSAndrea Arcangeli unlock_page(page); 1746ba76149fSAndrea Arcangeli putback_lru_page(page); 1747ba76149fSAndrea Arcangeli } 1748ba76149fSAndrea Arcangeli 1749ba76149fSAndrea Arcangeli static void release_pte_pages(pte_t *pte, pte_t *_pte) 1750ba76149fSAndrea Arcangeli { 1751ba76149fSAndrea Arcangeli while (--_pte >= pte) { 1752ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 1753ba76149fSAndrea Arcangeli if (!pte_none(pteval)) 1754ba76149fSAndrea Arcangeli release_pte_page(pte_page(pteval)); 1755ba76149fSAndrea Arcangeli } 1756ba76149fSAndrea Arcangeli } 1757ba76149fSAndrea Arcangeli 1758ba76149fSAndrea Arcangeli static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 1759ba76149fSAndrea Arcangeli unsigned long address, 1760ba76149fSAndrea Arcangeli pte_t *pte) 1761ba76149fSAndrea Arcangeli { 1762ba76149fSAndrea Arcangeli struct page *page; 1763ba76149fSAndrea Arcangeli pte_t *_pte; 1764344aa35cSBob Liu int referenced = 0, none = 0; 1765ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; 1766ba76149fSAndrea Arcangeli _pte++, address += PAGE_SIZE) { 1767ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 1768ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 1769ba76149fSAndrea Arcangeli if (++none <= khugepaged_max_ptes_none) 1770ba76149fSAndrea Arcangeli continue; 1771344aa35cSBob Liu else 1772ba76149fSAndrea Arcangeli goto out; 1773ba76149fSAndrea Arcangeli } 1774344aa35cSBob Liu if (!pte_present(pteval) || !pte_write(pteval)) 1775ba76149fSAndrea Arcangeli goto out; 1776ba76149fSAndrea Arcangeli page = vm_normal_page(vma, address, pteval); 1777344aa35cSBob Liu if (unlikely(!page)) 1778ba76149fSAndrea Arcangeli goto out; 1779344aa35cSBob Liu 1780ba76149fSAndrea Arcangeli VM_BUG_ON(PageCompound(page)); 1781ba76149fSAndrea Arcangeli BUG_ON(!PageAnon(page)); 1782ba76149fSAndrea Arcangeli VM_BUG_ON(!PageSwapBacked(page)); 1783ba76149fSAndrea Arcangeli 1784ba76149fSAndrea Arcangeli /* cannot use mapcount: can't collapse if there's a gup pin */ 1785344aa35cSBob Liu if (page_count(page) != 1) 1786ba76149fSAndrea Arcangeli goto out; 1787ba76149fSAndrea Arcangeli /* 1788ba76149fSAndrea Arcangeli * We can do it before isolate_lru_page because the 1789ba76149fSAndrea Arcangeli * page can't be freed from under us. NOTE: PG_lock 1790ba76149fSAndrea Arcangeli * is needed to serialize against split_huge_page 1791ba76149fSAndrea Arcangeli * when invoked from the VM. 1792ba76149fSAndrea Arcangeli */ 1793344aa35cSBob Liu if (!trylock_page(page)) 1794ba76149fSAndrea Arcangeli goto out; 1795ba76149fSAndrea Arcangeli /* 1796ba76149fSAndrea Arcangeli * Isolate the page to avoid collapsing an hugepage 1797ba76149fSAndrea Arcangeli * currently in use by the VM. 1798ba76149fSAndrea Arcangeli */ 1799ba76149fSAndrea Arcangeli if (isolate_lru_page(page)) { 1800ba76149fSAndrea Arcangeli unlock_page(page); 1801ba76149fSAndrea Arcangeli goto out; 1802ba76149fSAndrea Arcangeli } 1803ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 1804ba76149fSAndrea Arcangeli inc_zone_page_state(page, NR_ISOLATED_ANON + 0); 1805ba76149fSAndrea Arcangeli VM_BUG_ON(!PageLocked(page)); 1806ba76149fSAndrea Arcangeli VM_BUG_ON(PageLRU(page)); 1807ba76149fSAndrea Arcangeli 1808ba76149fSAndrea Arcangeli /* If there is no mapped pte young don't collapse the page */ 18098ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 18108ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 1811ba76149fSAndrea Arcangeli referenced = 1; 1812ba76149fSAndrea Arcangeli } 1813344aa35cSBob Liu if (likely(referenced)) 1814344aa35cSBob Liu return 1; 1815ba76149fSAndrea Arcangeli out: 1816344aa35cSBob Liu release_pte_pages(pte, _pte); 1817344aa35cSBob Liu return 0; 1818ba76149fSAndrea Arcangeli } 1819ba76149fSAndrea Arcangeli 1820ba76149fSAndrea Arcangeli static void __collapse_huge_page_copy(pte_t *pte, struct page *page, 1821ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 1822ba76149fSAndrea Arcangeli unsigned long address, 1823ba76149fSAndrea Arcangeli spinlock_t *ptl) 1824ba76149fSAndrea Arcangeli { 1825ba76149fSAndrea Arcangeli pte_t *_pte; 1826ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { 1827ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 1828ba76149fSAndrea Arcangeli struct page *src_page; 1829ba76149fSAndrea Arcangeli 1830ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 1831ba76149fSAndrea Arcangeli clear_user_highpage(page, address); 1832ba76149fSAndrea Arcangeli add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); 1833ba76149fSAndrea Arcangeli } else { 1834ba76149fSAndrea Arcangeli src_page = pte_page(pteval); 1835ba76149fSAndrea Arcangeli copy_user_highpage(page, src_page, address, vma); 1836ba76149fSAndrea Arcangeli VM_BUG_ON(page_mapcount(src_page) != 1); 1837ba76149fSAndrea Arcangeli release_pte_page(src_page); 1838ba76149fSAndrea Arcangeli /* 1839ba76149fSAndrea Arcangeli * ptl mostly unnecessary, but preempt has to 1840ba76149fSAndrea Arcangeli * be disabled to update the per-cpu stats 1841ba76149fSAndrea Arcangeli * inside page_remove_rmap(). 1842ba76149fSAndrea Arcangeli */ 1843ba76149fSAndrea Arcangeli spin_lock(ptl); 1844ba76149fSAndrea Arcangeli /* 1845ba76149fSAndrea Arcangeli * paravirt calls inside pte_clear here are 1846ba76149fSAndrea Arcangeli * superfluous. 1847ba76149fSAndrea Arcangeli */ 1848ba76149fSAndrea Arcangeli pte_clear(vma->vm_mm, address, _pte); 1849ba76149fSAndrea Arcangeli page_remove_rmap(src_page); 1850ba76149fSAndrea Arcangeli spin_unlock(ptl); 1851ba76149fSAndrea Arcangeli free_page_and_swap_cache(src_page); 1852ba76149fSAndrea Arcangeli } 1853ba76149fSAndrea Arcangeli 1854ba76149fSAndrea Arcangeli address += PAGE_SIZE; 1855ba76149fSAndrea Arcangeli page++; 1856ba76149fSAndrea Arcangeli } 1857ba76149fSAndrea Arcangeli } 1858ba76149fSAndrea Arcangeli 185926234f36SXiao Guangrong static void khugepaged_alloc_sleep(void) 186026234f36SXiao Guangrong { 186126234f36SXiao Guangrong wait_event_freezable_timeout(khugepaged_wait, false, 186226234f36SXiao Guangrong msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); 186326234f36SXiao Guangrong } 186426234f36SXiao Guangrong 186526234f36SXiao Guangrong #ifdef CONFIG_NUMA 186626234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 186726234f36SXiao Guangrong { 186826234f36SXiao Guangrong if (IS_ERR(*hpage)) { 186926234f36SXiao Guangrong if (!*wait) 187026234f36SXiao Guangrong return false; 187126234f36SXiao Guangrong 187226234f36SXiao Guangrong *wait = false; 1873e3b4126cSXiao Guangrong *hpage = NULL; 187426234f36SXiao Guangrong khugepaged_alloc_sleep(); 187526234f36SXiao Guangrong } else if (*hpage) { 187626234f36SXiao Guangrong put_page(*hpage); 187726234f36SXiao Guangrong *hpage = NULL; 187826234f36SXiao Guangrong } 187926234f36SXiao Guangrong 188026234f36SXiao Guangrong return true; 188126234f36SXiao Guangrong } 188226234f36SXiao Guangrong 188326234f36SXiao Guangrong static struct page 188426234f36SXiao Guangrong *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, 188526234f36SXiao Guangrong struct vm_area_struct *vma, unsigned long address, 188626234f36SXiao Guangrong int node) 188726234f36SXiao Guangrong { 188826234f36SXiao Guangrong VM_BUG_ON(*hpage); 188926234f36SXiao Guangrong /* 189026234f36SXiao Guangrong * Allocate the page while the vma is still valid and under 189126234f36SXiao Guangrong * the mmap_sem read mode so there is no memory allocation 189226234f36SXiao Guangrong * later when we take the mmap_sem in write mode. This is more 189326234f36SXiao Guangrong * friendly behavior (OTOH it may actually hide bugs) to 189426234f36SXiao Guangrong * filesystems in userland with daemons allocating memory in 189526234f36SXiao Guangrong * the userland I/O paths. Allocating memory with the 189626234f36SXiao Guangrong * mmap_sem in read mode is good idea also to allow greater 189726234f36SXiao Guangrong * scalability. 189826234f36SXiao Guangrong */ 189926234f36SXiao Guangrong *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address, 190026234f36SXiao Guangrong node, __GFP_OTHER_NODE); 190126234f36SXiao Guangrong 190226234f36SXiao Guangrong /* 190326234f36SXiao Guangrong * After allocating the hugepage, release the mmap_sem read lock in 190426234f36SXiao Guangrong * preparation for taking it in write mode. 190526234f36SXiao Guangrong */ 190626234f36SXiao Guangrong up_read(&mm->mmap_sem); 190726234f36SXiao Guangrong if (unlikely(!*hpage)) { 190826234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 190926234f36SXiao Guangrong *hpage = ERR_PTR(-ENOMEM); 191026234f36SXiao Guangrong return NULL; 191126234f36SXiao Guangrong } 191226234f36SXiao Guangrong 191326234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 191426234f36SXiao Guangrong return *hpage; 191526234f36SXiao Guangrong } 191626234f36SXiao Guangrong #else 191726234f36SXiao Guangrong static struct page *khugepaged_alloc_hugepage(bool *wait) 191826234f36SXiao Guangrong { 191926234f36SXiao Guangrong struct page *hpage; 192026234f36SXiao Guangrong 192126234f36SXiao Guangrong do { 192226234f36SXiao Guangrong hpage = alloc_hugepage(khugepaged_defrag()); 192326234f36SXiao Guangrong if (!hpage) { 192426234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 192526234f36SXiao Guangrong if (!*wait) 192626234f36SXiao Guangrong return NULL; 192726234f36SXiao Guangrong 192826234f36SXiao Guangrong *wait = false; 192926234f36SXiao Guangrong khugepaged_alloc_sleep(); 193026234f36SXiao Guangrong } else 193126234f36SXiao Guangrong count_vm_event(THP_COLLAPSE_ALLOC); 193226234f36SXiao Guangrong } while (unlikely(!hpage) && likely(khugepaged_enabled())); 193326234f36SXiao Guangrong 193426234f36SXiao Guangrong return hpage; 193526234f36SXiao Guangrong } 193626234f36SXiao Guangrong 193726234f36SXiao Guangrong static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) 193826234f36SXiao Guangrong { 193926234f36SXiao Guangrong if (!*hpage) 194026234f36SXiao Guangrong *hpage = khugepaged_alloc_hugepage(wait); 194126234f36SXiao Guangrong 194226234f36SXiao Guangrong if (unlikely(!*hpage)) 194326234f36SXiao Guangrong return false; 194426234f36SXiao Guangrong 194526234f36SXiao Guangrong return true; 194626234f36SXiao Guangrong } 194726234f36SXiao Guangrong 194826234f36SXiao Guangrong static struct page 194926234f36SXiao Guangrong *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, 195026234f36SXiao Guangrong struct vm_area_struct *vma, unsigned long address, 195126234f36SXiao Guangrong int node) 195226234f36SXiao Guangrong { 195326234f36SXiao Guangrong up_read(&mm->mmap_sem); 195426234f36SXiao Guangrong VM_BUG_ON(!*hpage); 195526234f36SXiao Guangrong return *hpage; 195626234f36SXiao Guangrong } 195726234f36SXiao Guangrong #endif 195826234f36SXiao Guangrong 1959fa475e51SBob Liu static bool hugepage_vma_check(struct vm_area_struct *vma) 1960fa475e51SBob Liu { 1961fa475e51SBob Liu if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || 1962fa475e51SBob Liu (vma->vm_flags & VM_NOHUGEPAGE)) 1963fa475e51SBob Liu return false; 1964fa475e51SBob Liu 1965fa475e51SBob Liu if (!vma->anon_vma || vma->vm_ops) 1966fa475e51SBob Liu return false; 1967fa475e51SBob Liu if (is_vma_temporary_stack(vma)) 1968fa475e51SBob Liu return false; 1969fa475e51SBob Liu VM_BUG_ON(vma->vm_flags & VM_NO_THP); 1970fa475e51SBob Liu return true; 1971fa475e51SBob Liu } 1972fa475e51SBob Liu 1973ba76149fSAndrea Arcangeli static void collapse_huge_page(struct mm_struct *mm, 1974ba76149fSAndrea Arcangeli unsigned long address, 1975ce83d217SAndrea Arcangeli struct page **hpage, 19765c4b4be3SAndi Kleen struct vm_area_struct *vma, 19775c4b4be3SAndi Kleen int node) 1978ba76149fSAndrea Arcangeli { 1979ba76149fSAndrea Arcangeli pmd_t *pmd, _pmd; 1980ba76149fSAndrea Arcangeli pte_t *pte; 1981ba76149fSAndrea Arcangeli pgtable_t pgtable; 1982ba76149fSAndrea Arcangeli struct page *new_page; 1983ba76149fSAndrea Arcangeli spinlock_t *ptl; 1984ba76149fSAndrea Arcangeli int isolated; 1985ba76149fSAndrea Arcangeli unsigned long hstart, hend; 19862ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 19872ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 1988ba76149fSAndrea Arcangeli 1989ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 1990692e0b35SAndrea Arcangeli 199126234f36SXiao Guangrong /* release the mmap_sem read lock. */ 199226234f36SXiao Guangrong new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); 199326234f36SXiao Guangrong if (!new_page) 1994ce83d217SAndrea Arcangeli return; 1995ce83d217SAndrea Arcangeli 1996420256efSXiao Guangrong if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) 1997692e0b35SAndrea Arcangeli return; 1998ba76149fSAndrea Arcangeli 1999ba76149fSAndrea Arcangeli /* 2000ba76149fSAndrea Arcangeli * Prevent all access to pagetables with the exception of 2001ba76149fSAndrea Arcangeli * gup_fast later hanlded by the ptep_clear_flush and the VM 2002ba76149fSAndrea Arcangeli * handled by the anon_vma lock + PG_lock. 2003ba76149fSAndrea Arcangeli */ 2004ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 2005ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2006ba76149fSAndrea Arcangeli goto out; 2007ba76149fSAndrea Arcangeli 2008ba76149fSAndrea Arcangeli vma = find_vma(mm, address); 2009ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2010ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2011ba76149fSAndrea Arcangeli if (address < hstart || address + HPAGE_PMD_SIZE > hend) 2012ba76149fSAndrea Arcangeli goto out; 2013fa475e51SBob Liu if (!hugepage_vma_check(vma)) 2014ba76149fSAndrea Arcangeli goto out; 20156219049aSBob Liu pmd = mm_find_pmd(mm, address); 20166219049aSBob Liu if (!pmd) 2017ba76149fSAndrea Arcangeli goto out; 20186219049aSBob Liu if (pmd_trans_huge(*pmd)) 2019ba76149fSAndrea Arcangeli goto out; 2020ba76149fSAndrea Arcangeli 2021ba76149fSAndrea Arcangeli anon_vma_lock(vma->anon_vma); 2022ba76149fSAndrea Arcangeli 2023ba76149fSAndrea Arcangeli pte = pte_offset_map(pmd, address); 2024ba76149fSAndrea Arcangeli ptl = pte_lockptr(mm, pmd); 2025ba76149fSAndrea Arcangeli 20262ec74c3eSSagi Grimberg mmun_start = address; 20272ec74c3eSSagi Grimberg mmun_end = address + HPAGE_PMD_SIZE; 20282ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2029ba76149fSAndrea Arcangeli spin_lock(&mm->page_table_lock); /* probably unnecessary */ 2030ba76149fSAndrea Arcangeli /* 2031ba76149fSAndrea Arcangeli * After this gup_fast can't run anymore. This also removes 2032ba76149fSAndrea Arcangeli * any huge TLB entry from the CPU so we won't allow 2033ba76149fSAndrea Arcangeli * huge and small TLB entries for the same virtual address 2034ba76149fSAndrea Arcangeli * to avoid the risk of CPU bugs in that area. 2035ba76149fSAndrea Arcangeli */ 20362ec74c3eSSagi Grimberg _pmd = pmdp_clear_flush(vma, address, pmd); 2037ba76149fSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 20382ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2039ba76149fSAndrea Arcangeli 2040ba76149fSAndrea Arcangeli spin_lock(ptl); 2041ba76149fSAndrea Arcangeli isolated = __collapse_huge_page_isolate(vma, address, pte); 2042ba76149fSAndrea Arcangeli spin_unlock(ptl); 2043ba76149fSAndrea Arcangeli 2044ba76149fSAndrea Arcangeli if (unlikely(!isolated)) { 2045453c7192SJohannes Weiner pte_unmap(pte); 2046ba76149fSAndrea Arcangeli spin_lock(&mm->page_table_lock); 2047ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 2048ba76149fSAndrea Arcangeli set_pmd_at(mm, address, pmd, _pmd); 2049ba76149fSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 2050ba76149fSAndrea Arcangeli anon_vma_unlock(vma->anon_vma); 2051ce83d217SAndrea Arcangeli goto out; 2052ba76149fSAndrea Arcangeli } 2053ba76149fSAndrea Arcangeli 2054ba76149fSAndrea Arcangeli /* 2055ba76149fSAndrea Arcangeli * All pages are isolated and locked so anon_vma rmap 2056ba76149fSAndrea Arcangeli * can't run anymore. 2057ba76149fSAndrea Arcangeli */ 2058ba76149fSAndrea Arcangeli anon_vma_unlock(vma->anon_vma); 2059ba76149fSAndrea Arcangeli 2060ba76149fSAndrea Arcangeli __collapse_huge_page_copy(pte, new_page, vma, address, ptl); 2061453c7192SJohannes Weiner pte_unmap(pte); 2062ba76149fSAndrea Arcangeli __SetPageUptodate(new_page); 2063ba76149fSAndrea Arcangeli pgtable = pmd_pgtable(_pmd); 2064ba76149fSAndrea Arcangeli 2065b3092b3bSBob Liu _pmd = mk_huge_pmd(new_page, vma); 2066ba76149fSAndrea Arcangeli 2067ba76149fSAndrea Arcangeli /* 2068ba76149fSAndrea Arcangeli * spin_lock() below is not the equivalent of smp_wmb(), so 2069ba76149fSAndrea Arcangeli * this is needed to avoid the copy_huge_page writes to become 2070ba76149fSAndrea Arcangeli * visible after the set_pmd_at() write. 2071ba76149fSAndrea Arcangeli */ 2072ba76149fSAndrea Arcangeli smp_wmb(); 2073ba76149fSAndrea Arcangeli 2074ba76149fSAndrea Arcangeli spin_lock(&mm->page_table_lock); 2075ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 2076ba76149fSAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, address); 2077ba76149fSAndrea Arcangeli set_pmd_at(mm, address, pmd, _pmd); 2078b113da65SDavid Miller update_mmu_cache_pmd(vma, address, pmd); 2079e3ebcf64SGerald Schaefer pgtable_trans_huge_deposit(mm, pgtable); 2080ba76149fSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 2081ba76149fSAndrea Arcangeli 2082ba76149fSAndrea Arcangeli *hpage = NULL; 2083420256efSXiao Guangrong 2084ba76149fSAndrea Arcangeli khugepaged_pages_collapsed++; 2085ce83d217SAndrea Arcangeli out_up_write: 2086ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 20870bbbc0b3SAndrea Arcangeli return; 20880bbbc0b3SAndrea Arcangeli 2089ce83d217SAndrea Arcangeli out: 2090678ff896SKAMEZAWA Hiroyuki mem_cgroup_uncharge_page(new_page); 2091ce83d217SAndrea Arcangeli goto out_up_write; 2092ba76149fSAndrea Arcangeli } 2093ba76149fSAndrea Arcangeli 2094ba76149fSAndrea Arcangeli static int khugepaged_scan_pmd(struct mm_struct *mm, 2095ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 2096ba76149fSAndrea Arcangeli unsigned long address, 2097ba76149fSAndrea Arcangeli struct page **hpage) 2098ba76149fSAndrea Arcangeli { 2099ba76149fSAndrea Arcangeli pmd_t *pmd; 2100ba76149fSAndrea Arcangeli pte_t *pte, *_pte; 2101ba76149fSAndrea Arcangeli int ret = 0, referenced = 0, none = 0; 2102ba76149fSAndrea Arcangeli struct page *page; 2103ba76149fSAndrea Arcangeli unsigned long _address; 2104ba76149fSAndrea Arcangeli spinlock_t *ptl; 21055c4b4be3SAndi Kleen int node = -1; 2106ba76149fSAndrea Arcangeli 2107ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 2108ba76149fSAndrea Arcangeli 21096219049aSBob Liu pmd = mm_find_pmd(mm, address); 21106219049aSBob Liu if (!pmd) 2111ba76149fSAndrea Arcangeli goto out; 21126219049aSBob Liu if (pmd_trans_huge(*pmd)) 2113ba76149fSAndrea Arcangeli goto out; 2114ba76149fSAndrea Arcangeli 2115ba76149fSAndrea Arcangeli pte = pte_offset_map_lock(mm, pmd, address, &ptl); 2116ba76149fSAndrea Arcangeli for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; 2117ba76149fSAndrea Arcangeli _pte++, _address += PAGE_SIZE) { 2118ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 2119ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 2120ba76149fSAndrea Arcangeli if (++none <= khugepaged_max_ptes_none) 2121ba76149fSAndrea Arcangeli continue; 2122ba76149fSAndrea Arcangeli else 2123ba76149fSAndrea Arcangeli goto out_unmap; 2124ba76149fSAndrea Arcangeli } 2125ba76149fSAndrea Arcangeli if (!pte_present(pteval) || !pte_write(pteval)) 2126ba76149fSAndrea Arcangeli goto out_unmap; 2127ba76149fSAndrea Arcangeli page = vm_normal_page(vma, _address, pteval); 2128ba76149fSAndrea Arcangeli if (unlikely(!page)) 2129ba76149fSAndrea Arcangeli goto out_unmap; 21305c4b4be3SAndi Kleen /* 21315c4b4be3SAndi Kleen * Chose the node of the first page. This could 21325c4b4be3SAndi Kleen * be more sophisticated and look at more pages, 21335c4b4be3SAndi Kleen * but isn't for now. 21345c4b4be3SAndi Kleen */ 21355c4b4be3SAndi Kleen if (node == -1) 21365c4b4be3SAndi Kleen node = page_to_nid(page); 2137ba76149fSAndrea Arcangeli VM_BUG_ON(PageCompound(page)); 2138ba76149fSAndrea Arcangeli if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) 2139ba76149fSAndrea Arcangeli goto out_unmap; 2140ba76149fSAndrea Arcangeli /* cannot use mapcount: can't collapse if there's a gup pin */ 2141ba76149fSAndrea Arcangeli if (page_count(page) != 1) 2142ba76149fSAndrea Arcangeli goto out_unmap; 21438ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 21448ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 2145ba76149fSAndrea Arcangeli referenced = 1; 2146ba76149fSAndrea Arcangeli } 2147ba76149fSAndrea Arcangeli if (referenced) 2148ba76149fSAndrea Arcangeli ret = 1; 2149ba76149fSAndrea Arcangeli out_unmap: 2150ba76149fSAndrea Arcangeli pte_unmap_unlock(pte, ptl); 2151ce83d217SAndrea Arcangeli if (ret) 2152ce83d217SAndrea Arcangeli /* collapse_huge_page will return with the mmap_sem released */ 21535c4b4be3SAndi Kleen collapse_huge_page(mm, address, hpage, vma, node); 2154ba76149fSAndrea Arcangeli out: 2155ba76149fSAndrea Arcangeli return ret; 2156ba76149fSAndrea Arcangeli } 2157ba76149fSAndrea Arcangeli 2158ba76149fSAndrea Arcangeli static void collect_mm_slot(struct mm_slot *mm_slot) 2159ba76149fSAndrea Arcangeli { 2160ba76149fSAndrea Arcangeli struct mm_struct *mm = mm_slot->mm; 2161ba76149fSAndrea Arcangeli 2162b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2163ba76149fSAndrea Arcangeli 2164ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm)) { 2165ba76149fSAndrea Arcangeli /* free mm_slot */ 2166ba76149fSAndrea Arcangeli hlist_del(&mm_slot->hash); 2167ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 2168ba76149fSAndrea Arcangeli 2169ba76149fSAndrea Arcangeli /* 2170ba76149fSAndrea Arcangeli * Not strictly needed because the mm exited already. 2171ba76149fSAndrea Arcangeli * 2172ba76149fSAndrea Arcangeli * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 2173ba76149fSAndrea Arcangeli */ 2174ba76149fSAndrea Arcangeli 2175ba76149fSAndrea Arcangeli /* khugepaged_mm_lock actually not necessary for the below */ 2176ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2177ba76149fSAndrea Arcangeli mmdrop(mm); 2178ba76149fSAndrea Arcangeli } 2179ba76149fSAndrea Arcangeli } 2180ba76149fSAndrea Arcangeli 2181ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_mm_slot(unsigned int pages, 2182ba76149fSAndrea Arcangeli struct page **hpage) 21832f1da642SH Hartley Sweeten __releases(&khugepaged_mm_lock) 21842f1da642SH Hartley Sweeten __acquires(&khugepaged_mm_lock) 2185ba76149fSAndrea Arcangeli { 2186ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2187ba76149fSAndrea Arcangeli struct mm_struct *mm; 2188ba76149fSAndrea Arcangeli struct vm_area_struct *vma; 2189ba76149fSAndrea Arcangeli int progress = 0; 2190ba76149fSAndrea Arcangeli 2191ba76149fSAndrea Arcangeli VM_BUG_ON(!pages); 2192b9980cdcSHugh Dickins VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); 2193ba76149fSAndrea Arcangeli 2194ba76149fSAndrea Arcangeli if (khugepaged_scan.mm_slot) 2195ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2196ba76149fSAndrea Arcangeli else { 2197ba76149fSAndrea Arcangeli mm_slot = list_entry(khugepaged_scan.mm_head.next, 2198ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2199ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2200ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = mm_slot; 2201ba76149fSAndrea Arcangeli } 2202ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2203ba76149fSAndrea Arcangeli 2204ba76149fSAndrea Arcangeli mm = mm_slot->mm; 2205ba76149fSAndrea Arcangeli down_read(&mm->mmap_sem); 2206ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2207ba76149fSAndrea Arcangeli vma = NULL; 2208ba76149fSAndrea Arcangeli else 2209ba76149fSAndrea Arcangeli vma = find_vma(mm, khugepaged_scan.address); 2210ba76149fSAndrea Arcangeli 2211ba76149fSAndrea Arcangeli progress++; 2212ba76149fSAndrea Arcangeli for (; vma; vma = vma->vm_next) { 2213ba76149fSAndrea Arcangeli unsigned long hstart, hend; 2214ba76149fSAndrea Arcangeli 2215ba76149fSAndrea Arcangeli cond_resched(); 2216ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) { 2217ba76149fSAndrea Arcangeli progress++; 2218ba76149fSAndrea Arcangeli break; 2219ba76149fSAndrea Arcangeli } 2220fa475e51SBob Liu if (!hugepage_vma_check(vma)) { 2221a7d6e4ecSAndrea Arcangeli skip: 2222ba76149fSAndrea Arcangeli progress++; 2223ba76149fSAndrea Arcangeli continue; 2224ba76149fSAndrea Arcangeli } 2225ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2226ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2227a7d6e4ecSAndrea Arcangeli if (hstart >= hend) 2228a7d6e4ecSAndrea Arcangeli goto skip; 2229a7d6e4ecSAndrea Arcangeli if (khugepaged_scan.address > hend) 2230a7d6e4ecSAndrea Arcangeli goto skip; 2231ba76149fSAndrea Arcangeli if (khugepaged_scan.address < hstart) 2232ba76149fSAndrea Arcangeli khugepaged_scan.address = hstart; 2233a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); 2234ba76149fSAndrea Arcangeli 2235ba76149fSAndrea Arcangeli while (khugepaged_scan.address < hend) { 2236ba76149fSAndrea Arcangeli int ret; 2237ba76149fSAndrea Arcangeli cond_resched(); 2238ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2239ba76149fSAndrea Arcangeli goto breakouterloop; 2240ba76149fSAndrea Arcangeli 2241ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address < hstart || 2242ba76149fSAndrea Arcangeli khugepaged_scan.address + HPAGE_PMD_SIZE > 2243ba76149fSAndrea Arcangeli hend); 2244ba76149fSAndrea Arcangeli ret = khugepaged_scan_pmd(mm, vma, 2245ba76149fSAndrea Arcangeli khugepaged_scan.address, 2246ba76149fSAndrea Arcangeli hpage); 2247ba76149fSAndrea Arcangeli /* move to next address */ 2248ba76149fSAndrea Arcangeli khugepaged_scan.address += HPAGE_PMD_SIZE; 2249ba76149fSAndrea Arcangeli progress += HPAGE_PMD_NR; 2250ba76149fSAndrea Arcangeli if (ret) 2251ba76149fSAndrea Arcangeli /* we released mmap_sem so break loop */ 2252ba76149fSAndrea Arcangeli goto breakouterloop_mmap_sem; 2253ba76149fSAndrea Arcangeli if (progress >= pages) 2254ba76149fSAndrea Arcangeli goto breakouterloop; 2255ba76149fSAndrea Arcangeli } 2256ba76149fSAndrea Arcangeli } 2257ba76149fSAndrea Arcangeli breakouterloop: 2258ba76149fSAndrea Arcangeli up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ 2259ba76149fSAndrea Arcangeli breakouterloop_mmap_sem: 2260ba76149fSAndrea Arcangeli 2261ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2262a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); 2263ba76149fSAndrea Arcangeli /* 2264ba76149fSAndrea Arcangeli * Release the current mm_slot if this mm is about to die, or 2265ba76149fSAndrea Arcangeli * if we scanned all vmas of this mm. 2266ba76149fSAndrea Arcangeli */ 2267ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm) || !vma) { 2268ba76149fSAndrea Arcangeli /* 2269ba76149fSAndrea Arcangeli * Make sure that if mm_users is reaching zero while 2270ba76149fSAndrea Arcangeli * khugepaged runs here, khugepaged_exit will find 2271ba76149fSAndrea Arcangeli * mm_slot not pointing to the exiting mm. 2272ba76149fSAndrea Arcangeli */ 2273ba76149fSAndrea Arcangeli if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { 2274ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = list_entry( 2275ba76149fSAndrea Arcangeli mm_slot->mm_node.next, 2276ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2277ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2278ba76149fSAndrea Arcangeli } else { 2279ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2280ba76149fSAndrea Arcangeli khugepaged_full_scans++; 2281ba76149fSAndrea Arcangeli } 2282ba76149fSAndrea Arcangeli 2283ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2284ba76149fSAndrea Arcangeli } 2285ba76149fSAndrea Arcangeli 2286ba76149fSAndrea Arcangeli return progress; 2287ba76149fSAndrea Arcangeli } 2288ba76149fSAndrea Arcangeli 2289ba76149fSAndrea Arcangeli static int khugepaged_has_work(void) 2290ba76149fSAndrea Arcangeli { 2291ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) && 2292ba76149fSAndrea Arcangeli khugepaged_enabled(); 2293ba76149fSAndrea Arcangeli } 2294ba76149fSAndrea Arcangeli 2295ba76149fSAndrea Arcangeli static int khugepaged_wait_event(void) 2296ba76149fSAndrea Arcangeli { 2297ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) || 22982017c0bfSXiao Guangrong kthread_should_stop(); 2299ba76149fSAndrea Arcangeli } 2300ba76149fSAndrea Arcangeli 2301d516904bSXiao Guangrong static void khugepaged_do_scan(void) 2302d516904bSXiao Guangrong { 2303d516904bSXiao Guangrong struct page *hpage = NULL; 2304ba76149fSAndrea Arcangeli unsigned int progress = 0, pass_through_head = 0; 2305ba76149fSAndrea Arcangeli unsigned int pages = khugepaged_pages_to_scan; 2306d516904bSXiao Guangrong bool wait = true; 2307ba76149fSAndrea Arcangeli 2308ba76149fSAndrea Arcangeli barrier(); /* write khugepaged_pages_to_scan to local stack */ 2309ba76149fSAndrea Arcangeli 2310ba76149fSAndrea Arcangeli while (progress < pages) { 231126234f36SXiao Guangrong if (!khugepaged_prealloc_page(&hpage, &wait)) 231226234f36SXiao Guangrong break; 2313d516904bSXiao Guangrong 2314420256efSXiao Guangrong cond_resched(); 2315ba76149fSAndrea Arcangeli 2316878aee7dSAndrea Arcangeli if (unlikely(kthread_should_stop() || freezing(current))) 2317878aee7dSAndrea Arcangeli break; 2318878aee7dSAndrea Arcangeli 2319ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2320ba76149fSAndrea Arcangeli if (!khugepaged_scan.mm_slot) 2321ba76149fSAndrea Arcangeli pass_through_head++; 2322ba76149fSAndrea Arcangeli if (khugepaged_has_work() && 2323ba76149fSAndrea Arcangeli pass_through_head < 2) 2324ba76149fSAndrea Arcangeli progress += khugepaged_scan_mm_slot(pages - progress, 2325d516904bSXiao Guangrong &hpage); 2326ba76149fSAndrea Arcangeli else 2327ba76149fSAndrea Arcangeli progress = pages; 2328ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2329ba76149fSAndrea Arcangeli } 2330ba76149fSAndrea Arcangeli 2331d516904bSXiao Guangrong if (!IS_ERR_OR_NULL(hpage)) 2332d516904bSXiao Guangrong put_page(hpage); 2333ba76149fSAndrea Arcangeli } 23340bbbc0b3SAndrea Arcangeli 23352017c0bfSXiao Guangrong static void khugepaged_wait_work(void) 23362017c0bfSXiao Guangrong { 23372017c0bfSXiao Guangrong try_to_freeze(); 23382017c0bfSXiao Guangrong 23392017c0bfSXiao Guangrong if (khugepaged_has_work()) { 23402017c0bfSXiao Guangrong if (!khugepaged_scan_sleep_millisecs) 23412017c0bfSXiao Guangrong return; 23422017c0bfSXiao Guangrong 23432017c0bfSXiao Guangrong wait_event_freezable_timeout(khugepaged_wait, 23442017c0bfSXiao Guangrong kthread_should_stop(), 23452017c0bfSXiao Guangrong msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); 23462017c0bfSXiao Guangrong return; 23472017c0bfSXiao Guangrong } 23482017c0bfSXiao Guangrong 23492017c0bfSXiao Guangrong if (khugepaged_enabled()) 23502017c0bfSXiao Guangrong wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); 23512017c0bfSXiao Guangrong } 23522017c0bfSXiao Guangrong 2353ba76149fSAndrea Arcangeli static int khugepaged(void *none) 2354ba76149fSAndrea Arcangeli { 2355ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2356ba76149fSAndrea Arcangeli 2357878aee7dSAndrea Arcangeli set_freezable(); 2358ba76149fSAndrea Arcangeli set_user_nice(current, 19); 2359ba76149fSAndrea Arcangeli 2360b7231789SXiao Guangrong while (!kthread_should_stop()) { 2361b7231789SXiao Guangrong khugepaged_do_scan(); 2362b7231789SXiao Guangrong khugepaged_wait_work(); 2363b7231789SXiao Guangrong } 2364ba76149fSAndrea Arcangeli 2365ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2366ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2367ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2368ba76149fSAndrea Arcangeli if (mm_slot) 2369ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2370ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2371ba76149fSAndrea Arcangeli return 0; 2372ba76149fSAndrea Arcangeli } 2373ba76149fSAndrea Arcangeli 237471e3aac0SAndrea Arcangeli void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd) 237571e3aac0SAndrea Arcangeli { 237671e3aac0SAndrea Arcangeli struct page *page; 237771e3aac0SAndrea Arcangeli 237871e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 237971e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(*pmd))) { 238071e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 238171e3aac0SAndrea Arcangeli return; 238271e3aac0SAndrea Arcangeli } 238371e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 238471e3aac0SAndrea Arcangeli VM_BUG_ON(!page_count(page)); 238571e3aac0SAndrea Arcangeli get_page(page); 238671e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 238771e3aac0SAndrea Arcangeli 238871e3aac0SAndrea Arcangeli split_huge_page(page); 238971e3aac0SAndrea Arcangeli 239071e3aac0SAndrea Arcangeli put_page(page); 239171e3aac0SAndrea Arcangeli BUG_ON(pmd_trans_huge(*pmd)); 239271e3aac0SAndrea Arcangeli } 239394fcc585SAndrea Arcangeli 239494fcc585SAndrea Arcangeli static void split_huge_page_address(struct mm_struct *mm, 239594fcc585SAndrea Arcangeli unsigned long address) 239694fcc585SAndrea Arcangeli { 239794fcc585SAndrea Arcangeli pmd_t *pmd; 239894fcc585SAndrea Arcangeli 239994fcc585SAndrea Arcangeli VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); 240094fcc585SAndrea Arcangeli 24016219049aSBob Liu pmd = mm_find_pmd(mm, address); 24026219049aSBob Liu if (!pmd) 240394fcc585SAndrea Arcangeli return; 240494fcc585SAndrea Arcangeli /* 240594fcc585SAndrea Arcangeli * Caller holds the mmap_sem write mode, so a huge pmd cannot 240694fcc585SAndrea Arcangeli * materialize from under us. 240794fcc585SAndrea Arcangeli */ 240894fcc585SAndrea Arcangeli split_huge_page_pmd(mm, pmd); 240994fcc585SAndrea Arcangeli } 241094fcc585SAndrea Arcangeli 241194fcc585SAndrea Arcangeli void __vma_adjust_trans_huge(struct vm_area_struct *vma, 241294fcc585SAndrea Arcangeli unsigned long start, 241394fcc585SAndrea Arcangeli unsigned long end, 241494fcc585SAndrea Arcangeli long adjust_next) 241594fcc585SAndrea Arcangeli { 241694fcc585SAndrea Arcangeli /* 241794fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 241894fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 241994fcc585SAndrea Arcangeli * an huge pmd. 242094fcc585SAndrea Arcangeli */ 242194fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 242294fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 242394fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 242494fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, start); 242594fcc585SAndrea Arcangeli 242694fcc585SAndrea Arcangeli /* 242794fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 242894fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 242994fcc585SAndrea Arcangeli * an huge pmd. 243094fcc585SAndrea Arcangeli */ 243194fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 243294fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 243394fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 243494fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, end); 243594fcc585SAndrea Arcangeli 243694fcc585SAndrea Arcangeli /* 243794fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 243894fcc585SAndrea Arcangeli * vm_next->vm_start isn't page aligned and it could previously 243994fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 244094fcc585SAndrea Arcangeli */ 244194fcc585SAndrea Arcangeli if (adjust_next > 0) { 244294fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 244394fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 244494fcc585SAndrea Arcangeli nstart += adjust_next << PAGE_SHIFT; 244594fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 244694fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 244794fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 244894fcc585SAndrea Arcangeli split_huge_page_address(next->vm_mm, nstart); 244994fcc585SAndrea Arcangeli } 245094fcc585SAndrea Arcangeli } 2451