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> 2071e3aac0SAndrea Arcangeli #include <asm/tlb.h> 2171e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 2271e3aac0SAndrea Arcangeli #include "internal.h" 2371e3aac0SAndrea Arcangeli 24ba76149fSAndrea Arcangeli /* 25ba76149fSAndrea Arcangeli * By default transparent hugepage support is enabled for all mappings 26ba76149fSAndrea Arcangeli * and khugepaged scans all mappings. Defrag is only invoked by 27ba76149fSAndrea Arcangeli * khugepaged hugepage allocations and by page faults inside 28ba76149fSAndrea Arcangeli * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived 29ba76149fSAndrea Arcangeli * allocations. 30ba76149fSAndrea Arcangeli */ 3171e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 3213ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 33ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 3413ece886SAndrea Arcangeli #endif 3513ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 3613ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 3713ece886SAndrea Arcangeli #endif 38d39d33c3SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| 39ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 40ba76149fSAndrea Arcangeli 41ba76149fSAndrea Arcangeli /* default scan 8*512 pte (or vmas) every 30 second */ 42ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; 43ba76149fSAndrea Arcangeli static unsigned int khugepaged_pages_collapsed; 44ba76149fSAndrea Arcangeli static unsigned int khugepaged_full_scans; 45ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; 46ba76149fSAndrea Arcangeli /* during fragmentation poll the hugepage allocator once every minute */ 47ba76149fSAndrea Arcangeli static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; 48ba76149fSAndrea Arcangeli static struct task_struct *khugepaged_thread __read_mostly; 49ba76149fSAndrea Arcangeli static DEFINE_MUTEX(khugepaged_mutex); 50ba76149fSAndrea Arcangeli static DEFINE_SPINLOCK(khugepaged_mm_lock); 51ba76149fSAndrea Arcangeli static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); 52ba76149fSAndrea Arcangeli /* 53ba76149fSAndrea Arcangeli * default collapse hugepages if there is at least one pte mapped like 54ba76149fSAndrea Arcangeli * it would have happened if the vma was large enough during page 55ba76149fSAndrea Arcangeli * fault. 56ba76149fSAndrea Arcangeli */ 57ba76149fSAndrea Arcangeli static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; 58ba76149fSAndrea Arcangeli 59ba76149fSAndrea Arcangeli static int khugepaged(void *none); 60ba76149fSAndrea Arcangeli static int mm_slots_hash_init(void); 61ba76149fSAndrea Arcangeli static int khugepaged_slab_init(void); 62ba76149fSAndrea Arcangeli static void khugepaged_slab_free(void); 63ba76149fSAndrea Arcangeli 64ba76149fSAndrea Arcangeli #define MM_SLOTS_HASH_HEADS 1024 65ba76149fSAndrea Arcangeli static struct hlist_head *mm_slots_hash __read_mostly; 66ba76149fSAndrea Arcangeli static struct kmem_cache *mm_slot_cache __read_mostly; 67ba76149fSAndrea Arcangeli 68ba76149fSAndrea Arcangeli /** 69ba76149fSAndrea Arcangeli * struct mm_slot - hash lookup from mm to mm_slot 70ba76149fSAndrea Arcangeli * @hash: hash collision list 71ba76149fSAndrea Arcangeli * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head 72ba76149fSAndrea Arcangeli * @mm: the mm that this information is valid for 73ba76149fSAndrea Arcangeli */ 74ba76149fSAndrea Arcangeli struct mm_slot { 75ba76149fSAndrea Arcangeli struct hlist_node hash; 76ba76149fSAndrea Arcangeli struct list_head mm_node; 77ba76149fSAndrea Arcangeli struct mm_struct *mm; 78ba76149fSAndrea Arcangeli }; 79ba76149fSAndrea Arcangeli 80ba76149fSAndrea Arcangeli /** 81ba76149fSAndrea Arcangeli * struct khugepaged_scan - cursor for scanning 82ba76149fSAndrea Arcangeli * @mm_head: the head of the mm list to scan 83ba76149fSAndrea Arcangeli * @mm_slot: the current mm_slot we are scanning 84ba76149fSAndrea Arcangeli * @address: the next address inside that to be scanned 85ba76149fSAndrea Arcangeli * 86ba76149fSAndrea Arcangeli * There is only the one khugepaged_scan instance of this cursor structure. 87ba76149fSAndrea Arcangeli */ 88ba76149fSAndrea Arcangeli struct khugepaged_scan { 89ba76149fSAndrea Arcangeli struct list_head mm_head; 90ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 91ba76149fSAndrea Arcangeli unsigned long address; 92ba76149fSAndrea Arcangeli } khugepaged_scan = { 93ba76149fSAndrea Arcangeli .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), 94ba76149fSAndrea Arcangeli }; 95ba76149fSAndrea Arcangeli 96f000565aSAndrea Arcangeli 97f000565aSAndrea Arcangeli static int set_recommended_min_free_kbytes(void) 98f000565aSAndrea Arcangeli { 99f000565aSAndrea Arcangeli struct zone *zone; 100f000565aSAndrea Arcangeli int nr_zones = 0; 101f000565aSAndrea Arcangeli unsigned long recommended_min; 102f000565aSAndrea Arcangeli extern int min_free_kbytes; 103f000565aSAndrea Arcangeli 104f000565aSAndrea Arcangeli if (!test_bit(TRANSPARENT_HUGEPAGE_FLAG, 105f000565aSAndrea Arcangeli &transparent_hugepage_flags) && 106f000565aSAndrea Arcangeli !test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 107f000565aSAndrea Arcangeli &transparent_hugepage_flags)) 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 int wakeup; 142ba76149fSAndrea Arcangeli if (unlikely(!mm_slot_cache || !mm_slots_hash)) { 143ba76149fSAndrea Arcangeli err = -ENOMEM; 144ba76149fSAndrea Arcangeli goto out; 145ba76149fSAndrea Arcangeli } 146ba76149fSAndrea Arcangeli mutex_lock(&khugepaged_mutex); 147ba76149fSAndrea Arcangeli if (!khugepaged_thread) 148ba76149fSAndrea Arcangeli khugepaged_thread = kthread_run(khugepaged, NULL, 149ba76149fSAndrea Arcangeli "khugepaged"); 150ba76149fSAndrea Arcangeli if (unlikely(IS_ERR(khugepaged_thread))) { 151ba76149fSAndrea Arcangeli printk(KERN_ERR 152ba76149fSAndrea Arcangeli "khugepaged: kthread_run(khugepaged) failed\n"); 153ba76149fSAndrea Arcangeli err = PTR_ERR(khugepaged_thread); 154ba76149fSAndrea Arcangeli khugepaged_thread = NULL; 155ba76149fSAndrea Arcangeli } 156ba76149fSAndrea Arcangeli wakeup = !list_empty(&khugepaged_scan.mm_head); 157ba76149fSAndrea Arcangeli mutex_unlock(&khugepaged_mutex); 158ba76149fSAndrea Arcangeli if (wakeup) 159ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 160f000565aSAndrea Arcangeli 161f000565aSAndrea Arcangeli set_recommended_min_free_kbytes(); 162ba76149fSAndrea Arcangeli } else 163ba76149fSAndrea Arcangeli /* wakeup to exit */ 164ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 165ba76149fSAndrea Arcangeli out: 166ba76149fSAndrea Arcangeli return err; 167ba76149fSAndrea Arcangeli } 16871e3aac0SAndrea Arcangeli 16971e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 170ba76149fSAndrea Arcangeli 17171e3aac0SAndrea Arcangeli static ssize_t double_flag_show(struct kobject *kobj, 17271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 17371e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 17471e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 17571e3aac0SAndrea Arcangeli { 17671e3aac0SAndrea Arcangeli if (test_bit(enabled, &transparent_hugepage_flags)) { 17771e3aac0SAndrea Arcangeli VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); 17871e3aac0SAndrea Arcangeli return sprintf(buf, "[always] madvise never\n"); 17971e3aac0SAndrea Arcangeli } else if (test_bit(req_madv, &transparent_hugepage_flags)) 18071e3aac0SAndrea Arcangeli return sprintf(buf, "always [madvise] never\n"); 18171e3aac0SAndrea Arcangeli else 18271e3aac0SAndrea Arcangeli return sprintf(buf, "always madvise [never]\n"); 18371e3aac0SAndrea Arcangeli } 18471e3aac0SAndrea Arcangeli static ssize_t double_flag_store(struct kobject *kobj, 18571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 18671e3aac0SAndrea Arcangeli const char *buf, size_t count, 18771e3aac0SAndrea Arcangeli enum transparent_hugepage_flag enabled, 18871e3aac0SAndrea Arcangeli enum transparent_hugepage_flag req_madv) 18971e3aac0SAndrea Arcangeli { 19071e3aac0SAndrea Arcangeli if (!memcmp("always", buf, 19171e3aac0SAndrea Arcangeli min(sizeof("always")-1, count))) { 19271e3aac0SAndrea Arcangeli set_bit(enabled, &transparent_hugepage_flags); 19371e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 19471e3aac0SAndrea Arcangeli } else if (!memcmp("madvise", buf, 19571e3aac0SAndrea Arcangeli min(sizeof("madvise")-1, count))) { 19671e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 19771e3aac0SAndrea Arcangeli set_bit(req_madv, &transparent_hugepage_flags); 19871e3aac0SAndrea Arcangeli } else if (!memcmp("never", buf, 19971e3aac0SAndrea Arcangeli min(sizeof("never")-1, count))) { 20071e3aac0SAndrea Arcangeli clear_bit(enabled, &transparent_hugepage_flags); 20171e3aac0SAndrea Arcangeli clear_bit(req_madv, &transparent_hugepage_flags); 20271e3aac0SAndrea Arcangeli } else 20371e3aac0SAndrea Arcangeli return -EINVAL; 20471e3aac0SAndrea Arcangeli 20571e3aac0SAndrea Arcangeli return count; 20671e3aac0SAndrea Arcangeli } 20771e3aac0SAndrea Arcangeli 20871e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 20971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 21071e3aac0SAndrea Arcangeli { 21171e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 21271e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 21371e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 21471e3aac0SAndrea Arcangeli } 21571e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 21671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 21771e3aac0SAndrea Arcangeli const char *buf, size_t count) 21871e3aac0SAndrea Arcangeli { 219ba76149fSAndrea Arcangeli ssize_t ret; 220ba76149fSAndrea Arcangeli 221ba76149fSAndrea Arcangeli ret = double_flag_store(kobj, attr, buf, count, 22271e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_FLAG, 22371e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); 224ba76149fSAndrea Arcangeli 225ba76149fSAndrea Arcangeli if (ret > 0) { 226ba76149fSAndrea Arcangeli int err = start_khugepaged(); 227ba76149fSAndrea Arcangeli if (err) 228ba76149fSAndrea Arcangeli ret = err; 229ba76149fSAndrea Arcangeli } 230ba76149fSAndrea Arcangeli 231f000565aSAndrea Arcangeli if (ret > 0 && 232f000565aSAndrea Arcangeli (test_bit(TRANSPARENT_HUGEPAGE_FLAG, 233f000565aSAndrea Arcangeli &transparent_hugepage_flags) || 234f000565aSAndrea Arcangeli test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 235f000565aSAndrea Arcangeli &transparent_hugepage_flags))) 236f000565aSAndrea Arcangeli set_recommended_min_free_kbytes(); 237f000565aSAndrea Arcangeli 238ba76149fSAndrea Arcangeli return ret; 23971e3aac0SAndrea Arcangeli } 24071e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 24171e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 24271e3aac0SAndrea Arcangeli 24371e3aac0SAndrea Arcangeli static ssize_t single_flag_show(struct kobject *kobj, 24471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 24571e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 24671e3aac0SAndrea Arcangeli { 24771e3aac0SAndrea Arcangeli if (test_bit(flag, &transparent_hugepage_flags)) 24871e3aac0SAndrea Arcangeli return sprintf(buf, "[yes] no\n"); 24971e3aac0SAndrea Arcangeli else 25071e3aac0SAndrea Arcangeli return sprintf(buf, "yes [no]\n"); 25171e3aac0SAndrea Arcangeli } 25271e3aac0SAndrea Arcangeli static ssize_t single_flag_store(struct kobject *kobj, 25371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 25471e3aac0SAndrea Arcangeli const char *buf, size_t count, 25571e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 25671e3aac0SAndrea Arcangeli { 25771e3aac0SAndrea Arcangeli if (!memcmp("yes", buf, 25871e3aac0SAndrea Arcangeli min(sizeof("yes")-1, count))) { 25971e3aac0SAndrea Arcangeli set_bit(flag, &transparent_hugepage_flags); 26071e3aac0SAndrea Arcangeli } else if (!memcmp("no", buf, 26171e3aac0SAndrea Arcangeli min(sizeof("no")-1, count))) { 26271e3aac0SAndrea Arcangeli clear_bit(flag, &transparent_hugepage_flags); 26371e3aac0SAndrea Arcangeli } else 26471e3aac0SAndrea Arcangeli return -EINVAL; 26571e3aac0SAndrea Arcangeli 26671e3aac0SAndrea Arcangeli return count; 26771e3aac0SAndrea Arcangeli } 26871e3aac0SAndrea Arcangeli 26971e3aac0SAndrea Arcangeli /* 27071e3aac0SAndrea Arcangeli * Currently defrag only disables __GFP_NOWAIT for allocation. A blind 27171e3aac0SAndrea Arcangeli * __GFP_REPEAT is too aggressive, it's never worth swapping tons of 27271e3aac0SAndrea Arcangeli * memory just to allocate one more hugepage. 27371e3aac0SAndrea Arcangeli */ 27471e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 27571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 27671e3aac0SAndrea Arcangeli { 27771e3aac0SAndrea Arcangeli return double_flag_show(kobj, attr, buf, 27871e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 27971e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 28071e3aac0SAndrea Arcangeli } 28171e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 28271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 28371e3aac0SAndrea Arcangeli const char *buf, size_t count) 28471e3aac0SAndrea Arcangeli { 28571e3aac0SAndrea Arcangeli return double_flag_store(kobj, attr, buf, count, 28671e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, 28771e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); 28871e3aac0SAndrea Arcangeli } 28971e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 29071e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 29171e3aac0SAndrea Arcangeli 29271e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 29371e3aac0SAndrea Arcangeli static ssize_t debug_cow_show(struct kobject *kobj, 29471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 29571e3aac0SAndrea Arcangeli { 29671e3aac0SAndrea Arcangeli return single_flag_show(kobj, attr, buf, 29771e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 29871e3aac0SAndrea Arcangeli } 29971e3aac0SAndrea Arcangeli static ssize_t debug_cow_store(struct kobject *kobj, 30071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 30171e3aac0SAndrea Arcangeli const char *buf, size_t count) 30271e3aac0SAndrea Arcangeli { 30371e3aac0SAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 30471e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 30571e3aac0SAndrea Arcangeli } 30671e3aac0SAndrea Arcangeli static struct kobj_attribute debug_cow_attr = 30771e3aac0SAndrea Arcangeli __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); 30871e3aac0SAndrea Arcangeli #endif /* CONFIG_DEBUG_VM */ 30971e3aac0SAndrea Arcangeli 31071e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 31171e3aac0SAndrea Arcangeli &enabled_attr.attr, 31271e3aac0SAndrea Arcangeli &defrag_attr.attr, 31371e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 31471e3aac0SAndrea Arcangeli &debug_cow_attr.attr, 31571e3aac0SAndrea Arcangeli #endif 31671e3aac0SAndrea Arcangeli NULL, 31771e3aac0SAndrea Arcangeli }; 31871e3aac0SAndrea Arcangeli 31971e3aac0SAndrea Arcangeli static struct attribute_group hugepage_attr_group = { 32071e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 321ba76149fSAndrea Arcangeli }; 322ba76149fSAndrea Arcangeli 323ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, 324ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 325ba76149fSAndrea Arcangeli char *buf) 326ba76149fSAndrea Arcangeli { 327ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); 328ba76149fSAndrea Arcangeli } 329ba76149fSAndrea Arcangeli 330ba76149fSAndrea Arcangeli static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, 331ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 332ba76149fSAndrea Arcangeli const char *buf, size_t count) 333ba76149fSAndrea Arcangeli { 334ba76149fSAndrea Arcangeli unsigned long msecs; 335ba76149fSAndrea Arcangeli int err; 336ba76149fSAndrea Arcangeli 337ba76149fSAndrea Arcangeli err = strict_strtoul(buf, 10, &msecs); 338ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 339ba76149fSAndrea Arcangeli return -EINVAL; 340ba76149fSAndrea Arcangeli 341ba76149fSAndrea Arcangeli khugepaged_scan_sleep_millisecs = msecs; 342ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 343ba76149fSAndrea Arcangeli 344ba76149fSAndrea Arcangeli return count; 345ba76149fSAndrea Arcangeli } 346ba76149fSAndrea Arcangeli static struct kobj_attribute scan_sleep_millisecs_attr = 347ba76149fSAndrea Arcangeli __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, 348ba76149fSAndrea Arcangeli scan_sleep_millisecs_store); 349ba76149fSAndrea Arcangeli 350ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, 351ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 352ba76149fSAndrea Arcangeli char *buf) 353ba76149fSAndrea Arcangeli { 354ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); 355ba76149fSAndrea Arcangeli } 356ba76149fSAndrea Arcangeli 357ba76149fSAndrea Arcangeli static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, 358ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 359ba76149fSAndrea Arcangeli const char *buf, size_t count) 360ba76149fSAndrea Arcangeli { 361ba76149fSAndrea Arcangeli unsigned long msecs; 362ba76149fSAndrea Arcangeli int err; 363ba76149fSAndrea Arcangeli 364ba76149fSAndrea Arcangeli err = strict_strtoul(buf, 10, &msecs); 365ba76149fSAndrea Arcangeli if (err || msecs > UINT_MAX) 366ba76149fSAndrea Arcangeli return -EINVAL; 367ba76149fSAndrea Arcangeli 368ba76149fSAndrea Arcangeli khugepaged_alloc_sleep_millisecs = msecs; 369ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 370ba76149fSAndrea Arcangeli 371ba76149fSAndrea Arcangeli return count; 372ba76149fSAndrea Arcangeli } 373ba76149fSAndrea Arcangeli static struct kobj_attribute alloc_sleep_millisecs_attr = 374ba76149fSAndrea Arcangeli __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, 375ba76149fSAndrea Arcangeli alloc_sleep_millisecs_store); 376ba76149fSAndrea Arcangeli 377ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_show(struct kobject *kobj, 378ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 379ba76149fSAndrea Arcangeli char *buf) 380ba76149fSAndrea Arcangeli { 381ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_to_scan); 382ba76149fSAndrea Arcangeli } 383ba76149fSAndrea Arcangeli static ssize_t pages_to_scan_store(struct kobject *kobj, 384ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 385ba76149fSAndrea Arcangeli const char *buf, size_t count) 386ba76149fSAndrea Arcangeli { 387ba76149fSAndrea Arcangeli int err; 388ba76149fSAndrea Arcangeli unsigned long pages; 389ba76149fSAndrea Arcangeli 390ba76149fSAndrea Arcangeli err = strict_strtoul(buf, 10, &pages); 391ba76149fSAndrea Arcangeli if (err || !pages || pages > UINT_MAX) 392ba76149fSAndrea Arcangeli return -EINVAL; 393ba76149fSAndrea Arcangeli 394ba76149fSAndrea Arcangeli khugepaged_pages_to_scan = pages; 395ba76149fSAndrea Arcangeli 396ba76149fSAndrea Arcangeli return count; 397ba76149fSAndrea Arcangeli } 398ba76149fSAndrea Arcangeli static struct kobj_attribute pages_to_scan_attr = 399ba76149fSAndrea Arcangeli __ATTR(pages_to_scan, 0644, pages_to_scan_show, 400ba76149fSAndrea Arcangeli pages_to_scan_store); 401ba76149fSAndrea Arcangeli 402ba76149fSAndrea Arcangeli static ssize_t pages_collapsed_show(struct kobject *kobj, 403ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 404ba76149fSAndrea Arcangeli char *buf) 405ba76149fSAndrea Arcangeli { 406ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_pages_collapsed); 407ba76149fSAndrea Arcangeli } 408ba76149fSAndrea Arcangeli static struct kobj_attribute pages_collapsed_attr = 409ba76149fSAndrea Arcangeli __ATTR_RO(pages_collapsed); 410ba76149fSAndrea Arcangeli 411ba76149fSAndrea Arcangeli static ssize_t full_scans_show(struct kobject *kobj, 412ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 413ba76149fSAndrea Arcangeli char *buf) 414ba76149fSAndrea Arcangeli { 415ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_full_scans); 416ba76149fSAndrea Arcangeli } 417ba76149fSAndrea Arcangeli static struct kobj_attribute full_scans_attr = 418ba76149fSAndrea Arcangeli __ATTR_RO(full_scans); 419ba76149fSAndrea Arcangeli 420ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_show(struct kobject *kobj, 421ba76149fSAndrea Arcangeli struct kobj_attribute *attr, char *buf) 422ba76149fSAndrea Arcangeli { 423ba76149fSAndrea Arcangeli return single_flag_show(kobj, attr, buf, 424ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 425ba76149fSAndrea Arcangeli } 426ba76149fSAndrea Arcangeli static ssize_t khugepaged_defrag_store(struct kobject *kobj, 427ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 428ba76149fSAndrea Arcangeli const char *buf, size_t count) 429ba76149fSAndrea Arcangeli { 430ba76149fSAndrea Arcangeli return single_flag_store(kobj, attr, buf, count, 431ba76149fSAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); 432ba76149fSAndrea Arcangeli } 433ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_defrag_attr = 434ba76149fSAndrea Arcangeli __ATTR(defrag, 0644, khugepaged_defrag_show, 435ba76149fSAndrea Arcangeli khugepaged_defrag_store); 436ba76149fSAndrea Arcangeli 437ba76149fSAndrea Arcangeli /* 438ba76149fSAndrea Arcangeli * max_ptes_none controls if khugepaged should collapse hugepages over 439ba76149fSAndrea Arcangeli * any unmapped ptes in turn potentially increasing the memory 440ba76149fSAndrea Arcangeli * footprint of the vmas. When max_ptes_none is 0 khugepaged will not 441ba76149fSAndrea Arcangeli * reduce the available free memory in the system as it 442ba76149fSAndrea Arcangeli * runs. Increasing max_ptes_none will instead potentially reduce the 443ba76149fSAndrea Arcangeli * free memory in the system during the khugepaged scan. 444ba76149fSAndrea Arcangeli */ 445ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, 446ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 447ba76149fSAndrea Arcangeli char *buf) 448ba76149fSAndrea Arcangeli { 449ba76149fSAndrea Arcangeli return sprintf(buf, "%u\n", khugepaged_max_ptes_none); 450ba76149fSAndrea Arcangeli } 451ba76149fSAndrea Arcangeli static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, 452ba76149fSAndrea Arcangeli struct kobj_attribute *attr, 453ba76149fSAndrea Arcangeli const char *buf, size_t count) 454ba76149fSAndrea Arcangeli { 455ba76149fSAndrea Arcangeli int err; 456ba76149fSAndrea Arcangeli unsigned long max_ptes_none; 457ba76149fSAndrea Arcangeli 458ba76149fSAndrea Arcangeli err = strict_strtoul(buf, 10, &max_ptes_none); 459ba76149fSAndrea Arcangeli if (err || max_ptes_none > HPAGE_PMD_NR-1) 460ba76149fSAndrea Arcangeli return -EINVAL; 461ba76149fSAndrea Arcangeli 462ba76149fSAndrea Arcangeli khugepaged_max_ptes_none = max_ptes_none; 463ba76149fSAndrea Arcangeli 464ba76149fSAndrea Arcangeli return count; 465ba76149fSAndrea Arcangeli } 466ba76149fSAndrea Arcangeli static struct kobj_attribute khugepaged_max_ptes_none_attr = 467ba76149fSAndrea Arcangeli __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, 468ba76149fSAndrea Arcangeli khugepaged_max_ptes_none_store); 469ba76149fSAndrea Arcangeli 470ba76149fSAndrea Arcangeli static struct attribute *khugepaged_attr[] = { 471ba76149fSAndrea Arcangeli &khugepaged_defrag_attr.attr, 472ba76149fSAndrea Arcangeli &khugepaged_max_ptes_none_attr.attr, 473ba76149fSAndrea Arcangeli &pages_to_scan_attr.attr, 474ba76149fSAndrea Arcangeli &pages_collapsed_attr.attr, 475ba76149fSAndrea Arcangeli &full_scans_attr.attr, 476ba76149fSAndrea Arcangeli &scan_sleep_millisecs_attr.attr, 477ba76149fSAndrea Arcangeli &alloc_sleep_millisecs_attr.attr, 478ba76149fSAndrea Arcangeli NULL, 479ba76149fSAndrea Arcangeli }; 480ba76149fSAndrea Arcangeli 481ba76149fSAndrea Arcangeli static struct attribute_group khugepaged_attr_group = { 482ba76149fSAndrea Arcangeli .attrs = khugepaged_attr, 483ba76149fSAndrea Arcangeli .name = "khugepaged", 48471e3aac0SAndrea Arcangeli }; 48571e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 48671e3aac0SAndrea Arcangeli 48771e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 48871e3aac0SAndrea Arcangeli { 48971e3aac0SAndrea Arcangeli int err; 490ba76149fSAndrea Arcangeli #ifdef CONFIG_SYSFS 491ba76149fSAndrea Arcangeli static struct kobject *hugepage_kobj; 4924b7167b9SAndrea Arcangeli #endif 49371e3aac0SAndrea Arcangeli 4944b7167b9SAndrea Arcangeli err = -EINVAL; 4954b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 4964b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 4974b7167b9SAndrea Arcangeli goto out; 4984b7167b9SAndrea Arcangeli } 4994b7167b9SAndrea Arcangeli 5004b7167b9SAndrea Arcangeli #ifdef CONFIG_SYSFS 501ba76149fSAndrea Arcangeli err = -ENOMEM; 502ba76149fSAndrea Arcangeli hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 503ba76149fSAndrea Arcangeli if (unlikely(!hugepage_kobj)) { 504ba76149fSAndrea Arcangeli printk(KERN_ERR "hugepage: failed kobject create\n"); 505ba76149fSAndrea Arcangeli goto out; 506ba76149fSAndrea Arcangeli } 507ba76149fSAndrea Arcangeli 508ba76149fSAndrea Arcangeli err = sysfs_create_group(hugepage_kobj, &hugepage_attr_group); 509ba76149fSAndrea Arcangeli if (err) { 510ba76149fSAndrea Arcangeli printk(KERN_ERR "hugepage: failed register hugeage group\n"); 511ba76149fSAndrea Arcangeli goto out; 512ba76149fSAndrea Arcangeli } 513ba76149fSAndrea Arcangeli 514ba76149fSAndrea Arcangeli err = sysfs_create_group(hugepage_kobj, &khugepaged_attr_group); 515ba76149fSAndrea Arcangeli if (err) { 516ba76149fSAndrea Arcangeli printk(KERN_ERR "hugepage: failed register hugeage group\n"); 517ba76149fSAndrea Arcangeli goto out; 518ba76149fSAndrea Arcangeli } 51971e3aac0SAndrea Arcangeli #endif 520ba76149fSAndrea Arcangeli 521ba76149fSAndrea Arcangeli err = khugepaged_slab_init(); 522ba76149fSAndrea Arcangeli if (err) 523ba76149fSAndrea Arcangeli goto out; 524ba76149fSAndrea Arcangeli 525ba76149fSAndrea Arcangeli err = mm_slots_hash_init(); 526ba76149fSAndrea Arcangeli if (err) { 527ba76149fSAndrea Arcangeli khugepaged_slab_free(); 528ba76149fSAndrea Arcangeli goto out; 529ba76149fSAndrea Arcangeli } 530ba76149fSAndrea Arcangeli 53197562cd2SRik van Riel /* 53297562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 53397562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 53497562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 53597562cd2SRik van Riel */ 53697562cd2SRik van Riel if (totalram_pages < (512 << (20 - PAGE_SHIFT))) 53797562cd2SRik van Riel transparent_hugepage_flags = 0; 53897562cd2SRik van Riel 539ba76149fSAndrea Arcangeli start_khugepaged(); 540ba76149fSAndrea Arcangeli 541f000565aSAndrea Arcangeli set_recommended_min_free_kbytes(); 542f000565aSAndrea Arcangeli 543ba76149fSAndrea Arcangeli out: 544ba76149fSAndrea Arcangeli return err; 54571e3aac0SAndrea Arcangeli } 54671e3aac0SAndrea Arcangeli module_init(hugepage_init) 54771e3aac0SAndrea Arcangeli 54871e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 54971e3aac0SAndrea Arcangeli { 55071e3aac0SAndrea Arcangeli int ret = 0; 55171e3aac0SAndrea Arcangeli if (!str) 55271e3aac0SAndrea Arcangeli goto out; 55371e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 55471e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 55571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 55671e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 55771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 55871e3aac0SAndrea Arcangeli ret = 1; 55971e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 56071e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 56171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56271e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 56371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56471e3aac0SAndrea Arcangeli ret = 1; 56571e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 56671e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 56771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 56971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 57071e3aac0SAndrea Arcangeli ret = 1; 57171e3aac0SAndrea Arcangeli } 57271e3aac0SAndrea Arcangeli out: 57371e3aac0SAndrea Arcangeli if (!ret) 57471e3aac0SAndrea Arcangeli printk(KERN_WARNING 57571e3aac0SAndrea Arcangeli "transparent_hugepage= cannot parse, ignored\n"); 57671e3aac0SAndrea Arcangeli return ret; 57771e3aac0SAndrea Arcangeli } 57871e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 57971e3aac0SAndrea Arcangeli 58071e3aac0SAndrea Arcangeli static void prepare_pmd_huge_pte(pgtable_t pgtable, 58171e3aac0SAndrea Arcangeli struct mm_struct *mm) 58271e3aac0SAndrea Arcangeli { 58371e3aac0SAndrea Arcangeli assert_spin_locked(&mm->page_table_lock); 58471e3aac0SAndrea Arcangeli 58571e3aac0SAndrea Arcangeli /* FIFO */ 58671e3aac0SAndrea Arcangeli if (!mm->pmd_huge_pte) 58771e3aac0SAndrea Arcangeli INIT_LIST_HEAD(&pgtable->lru); 58871e3aac0SAndrea Arcangeli else 58971e3aac0SAndrea Arcangeli list_add(&pgtable->lru, &mm->pmd_huge_pte->lru); 59071e3aac0SAndrea Arcangeli mm->pmd_huge_pte = pgtable; 59171e3aac0SAndrea Arcangeli } 59271e3aac0SAndrea Arcangeli 59371e3aac0SAndrea Arcangeli static inline pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 59471e3aac0SAndrea Arcangeli { 59571e3aac0SAndrea Arcangeli if (likely(vma->vm_flags & VM_WRITE)) 59671e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 59771e3aac0SAndrea Arcangeli return pmd; 59871e3aac0SAndrea Arcangeli } 59971e3aac0SAndrea Arcangeli 60071e3aac0SAndrea Arcangeli static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, 60171e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 60271e3aac0SAndrea Arcangeli unsigned long haddr, pmd_t *pmd, 60371e3aac0SAndrea Arcangeli struct page *page) 60471e3aac0SAndrea Arcangeli { 60571e3aac0SAndrea Arcangeli int ret = 0; 60671e3aac0SAndrea Arcangeli pgtable_t pgtable; 60771e3aac0SAndrea Arcangeli 60871e3aac0SAndrea Arcangeli VM_BUG_ON(!PageCompound(page)); 60971e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(mm, haddr); 61071e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) { 611b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(page); 61271e3aac0SAndrea Arcangeli put_page(page); 61371e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 61471e3aac0SAndrea Arcangeli } 61571e3aac0SAndrea Arcangeli 61671e3aac0SAndrea Arcangeli clear_huge_page(page, haddr, HPAGE_PMD_NR); 61771e3aac0SAndrea Arcangeli __SetPageUptodate(page); 61871e3aac0SAndrea Arcangeli 61971e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 62071e3aac0SAndrea Arcangeli if (unlikely(!pmd_none(*pmd))) { 62171e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 622b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(page); 62371e3aac0SAndrea Arcangeli put_page(page); 62471e3aac0SAndrea Arcangeli pte_free(mm, pgtable); 62571e3aac0SAndrea Arcangeli } else { 62671e3aac0SAndrea Arcangeli pmd_t entry; 62771e3aac0SAndrea Arcangeli entry = mk_pmd(page, vma->vm_page_prot); 62871e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 62971e3aac0SAndrea Arcangeli entry = pmd_mkhuge(entry); 63071e3aac0SAndrea Arcangeli /* 63171e3aac0SAndrea Arcangeli * The spinlocking to take the lru_lock inside 63271e3aac0SAndrea Arcangeli * page_add_new_anon_rmap() acts as a full memory 63371e3aac0SAndrea Arcangeli * barrier to be sure clear_huge_page writes become 63471e3aac0SAndrea Arcangeli * visible after the set_pmd_at() write. 63571e3aac0SAndrea Arcangeli */ 63671e3aac0SAndrea Arcangeli page_add_new_anon_rmap(page, vma, haddr); 63771e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 63871e3aac0SAndrea Arcangeli prepare_pmd_huge_pte(pgtable, mm); 63971e3aac0SAndrea Arcangeli add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); 64071e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 64171e3aac0SAndrea Arcangeli } 64271e3aac0SAndrea Arcangeli 64371e3aac0SAndrea Arcangeli return ret; 64471e3aac0SAndrea Arcangeli } 64571e3aac0SAndrea Arcangeli 646cc5d462fSAndi Kleen static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) 6470bbbc0b3SAndrea Arcangeli { 648cc5d462fSAndi Kleen return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; 6490bbbc0b3SAndrea Arcangeli } 6500bbbc0b3SAndrea Arcangeli 6510bbbc0b3SAndrea Arcangeli static inline struct page *alloc_hugepage_vma(int defrag, 6520bbbc0b3SAndrea Arcangeli struct vm_area_struct *vma, 653cc5d462fSAndi Kleen unsigned long haddr, int nd, 654cc5d462fSAndi Kleen gfp_t extra_gfp) 6550bbbc0b3SAndrea Arcangeli { 656cc5d462fSAndi Kleen return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), 6575c4b4be3SAndi Kleen HPAGE_PMD_ORDER, vma, haddr, nd); 6580bbbc0b3SAndrea Arcangeli } 6590bbbc0b3SAndrea Arcangeli 6600bbbc0b3SAndrea Arcangeli #ifndef CONFIG_NUMA 66171e3aac0SAndrea Arcangeli static inline struct page *alloc_hugepage(int defrag) 66271e3aac0SAndrea Arcangeli { 663cc5d462fSAndi Kleen return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), 66471e3aac0SAndrea Arcangeli HPAGE_PMD_ORDER); 66571e3aac0SAndrea Arcangeli } 6660bbbc0b3SAndrea Arcangeli #endif 66771e3aac0SAndrea Arcangeli 66871e3aac0SAndrea Arcangeli int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 66971e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, 67071e3aac0SAndrea Arcangeli unsigned int flags) 67171e3aac0SAndrea Arcangeli { 67271e3aac0SAndrea Arcangeli struct page *page; 67371e3aac0SAndrea Arcangeli unsigned long haddr = address & HPAGE_PMD_MASK; 67471e3aac0SAndrea Arcangeli pte_t *pte; 67571e3aac0SAndrea Arcangeli 67671e3aac0SAndrea Arcangeli if (haddr >= vma->vm_start && haddr + HPAGE_PMD_SIZE <= vma->vm_end) { 67771e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 67871e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 679ba76149fSAndrea Arcangeli if (unlikely(khugepaged_enter(vma))) 680ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 6810bbbc0b3SAndrea Arcangeli page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), 682cc5d462fSAndi Kleen vma, haddr, numa_node_id(), 0); 683*81ab4201SAndi Kleen if (unlikely(!page)) { 684*81ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 68571e3aac0SAndrea Arcangeli goto out; 686*81ab4201SAndi Kleen } 687*81ab4201SAndi Kleen count_vm_event(THP_FAULT_ALLOC); 688b9bbfbe3SAndrea Arcangeli if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { 689b9bbfbe3SAndrea Arcangeli put_page(page); 690b9bbfbe3SAndrea Arcangeli goto out; 691b9bbfbe3SAndrea Arcangeli } 69271e3aac0SAndrea Arcangeli 69371e3aac0SAndrea Arcangeli return __do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page); 69471e3aac0SAndrea Arcangeli } 69571e3aac0SAndrea Arcangeli out: 69671e3aac0SAndrea Arcangeli /* 69771e3aac0SAndrea Arcangeli * Use __pte_alloc instead of pte_alloc_map, because we can't 69871e3aac0SAndrea Arcangeli * run pte_offset_map on the pmd, if an huge pmd could 69971e3aac0SAndrea Arcangeli * materialize from under us from a different thread. 70071e3aac0SAndrea Arcangeli */ 70171e3aac0SAndrea Arcangeli if (unlikely(__pte_alloc(mm, vma, pmd, address))) 70271e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 70371e3aac0SAndrea Arcangeli /* if an huge pmd materialized from under us just retry later */ 70471e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_huge(*pmd))) 70571e3aac0SAndrea Arcangeli return 0; 70671e3aac0SAndrea Arcangeli /* 70771e3aac0SAndrea Arcangeli * A regular pmd is established and it can't morph into a huge pmd 70871e3aac0SAndrea Arcangeli * from under us anymore at this point because we hold the mmap_sem 70971e3aac0SAndrea Arcangeli * read mode and khugepaged takes it in write mode. So now it's 71071e3aac0SAndrea Arcangeli * safe to run pte_offset_map(). 71171e3aac0SAndrea Arcangeli */ 71271e3aac0SAndrea Arcangeli pte = pte_offset_map(pmd, address); 71371e3aac0SAndrea Arcangeli return handle_pte_fault(mm, vma, address, pte, pmd, flags); 71471e3aac0SAndrea Arcangeli } 71571e3aac0SAndrea Arcangeli 71671e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 71771e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 71871e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 71971e3aac0SAndrea Arcangeli { 72071e3aac0SAndrea Arcangeli struct page *src_page; 72171e3aac0SAndrea Arcangeli pmd_t pmd; 72271e3aac0SAndrea Arcangeli pgtable_t pgtable; 72371e3aac0SAndrea Arcangeli int ret; 72471e3aac0SAndrea Arcangeli 72571e3aac0SAndrea Arcangeli ret = -ENOMEM; 72671e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(dst_mm, addr); 72771e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 72871e3aac0SAndrea Arcangeli goto out; 72971e3aac0SAndrea Arcangeli 73071e3aac0SAndrea Arcangeli spin_lock(&dst_mm->page_table_lock); 73171e3aac0SAndrea Arcangeli spin_lock_nested(&src_mm->page_table_lock, SINGLE_DEPTH_NESTING); 73271e3aac0SAndrea Arcangeli 73371e3aac0SAndrea Arcangeli ret = -EAGAIN; 73471e3aac0SAndrea Arcangeli pmd = *src_pmd; 73571e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(pmd))) { 73671e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 73771e3aac0SAndrea Arcangeli goto out_unlock; 73871e3aac0SAndrea Arcangeli } 73971e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_splitting(pmd))) { 74071e3aac0SAndrea Arcangeli /* split huge page running from under us */ 74171e3aac0SAndrea Arcangeli spin_unlock(&src_mm->page_table_lock); 74271e3aac0SAndrea Arcangeli spin_unlock(&dst_mm->page_table_lock); 74371e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 74471e3aac0SAndrea Arcangeli 74571e3aac0SAndrea Arcangeli wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ 74671e3aac0SAndrea Arcangeli goto out; 74771e3aac0SAndrea Arcangeli } 74871e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 74971e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(src_page)); 75071e3aac0SAndrea Arcangeli get_page(src_page); 75171e3aac0SAndrea Arcangeli page_dup_rmap(src_page); 75271e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 75371e3aac0SAndrea Arcangeli 75471e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 75571e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 75671e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 75771e3aac0SAndrea Arcangeli prepare_pmd_huge_pte(pgtable, dst_mm); 75871e3aac0SAndrea Arcangeli 75971e3aac0SAndrea Arcangeli ret = 0; 76071e3aac0SAndrea Arcangeli out_unlock: 76171e3aac0SAndrea Arcangeli spin_unlock(&src_mm->page_table_lock); 76271e3aac0SAndrea Arcangeli spin_unlock(&dst_mm->page_table_lock); 76371e3aac0SAndrea Arcangeli out: 76471e3aac0SAndrea Arcangeli return ret; 76571e3aac0SAndrea Arcangeli } 76671e3aac0SAndrea Arcangeli 76771e3aac0SAndrea Arcangeli /* no "address" argument so destroys page coloring of some arch */ 76871e3aac0SAndrea Arcangeli pgtable_t get_pmd_huge_pte(struct mm_struct *mm) 76971e3aac0SAndrea Arcangeli { 77071e3aac0SAndrea Arcangeli pgtable_t pgtable; 77171e3aac0SAndrea Arcangeli 77271e3aac0SAndrea Arcangeli assert_spin_locked(&mm->page_table_lock); 77371e3aac0SAndrea Arcangeli 77471e3aac0SAndrea Arcangeli /* FIFO */ 77571e3aac0SAndrea Arcangeli pgtable = mm->pmd_huge_pte; 77671e3aac0SAndrea Arcangeli if (list_empty(&pgtable->lru)) 77771e3aac0SAndrea Arcangeli mm->pmd_huge_pte = NULL; 77871e3aac0SAndrea Arcangeli else { 77971e3aac0SAndrea Arcangeli mm->pmd_huge_pte = list_entry(pgtable->lru.next, 78071e3aac0SAndrea Arcangeli struct page, lru); 78171e3aac0SAndrea Arcangeli list_del(&pgtable->lru); 78271e3aac0SAndrea Arcangeli } 78371e3aac0SAndrea Arcangeli return pgtable; 78471e3aac0SAndrea Arcangeli } 78571e3aac0SAndrea Arcangeli 78671e3aac0SAndrea Arcangeli static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, 78771e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 78871e3aac0SAndrea Arcangeli unsigned long address, 78971e3aac0SAndrea Arcangeli pmd_t *pmd, pmd_t orig_pmd, 79071e3aac0SAndrea Arcangeli struct page *page, 79171e3aac0SAndrea Arcangeli unsigned long haddr) 79271e3aac0SAndrea Arcangeli { 79371e3aac0SAndrea Arcangeli pgtable_t pgtable; 79471e3aac0SAndrea Arcangeli pmd_t _pmd; 79571e3aac0SAndrea Arcangeli int ret = 0, i; 79671e3aac0SAndrea Arcangeli struct page **pages; 79771e3aac0SAndrea Arcangeli 79871e3aac0SAndrea Arcangeli pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, 79971e3aac0SAndrea Arcangeli GFP_KERNEL); 80071e3aac0SAndrea Arcangeli if (unlikely(!pages)) { 80171e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 80271e3aac0SAndrea Arcangeli goto out; 80371e3aac0SAndrea Arcangeli } 80471e3aac0SAndrea Arcangeli 80571e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 806cc5d462fSAndi Kleen pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | 807cc5d462fSAndi Kleen __GFP_OTHER_NODE, 80819ee151eSAndi Kleen vma, address, page_to_nid(page)); 809b9bbfbe3SAndrea Arcangeli if (unlikely(!pages[i] || 810b9bbfbe3SAndrea Arcangeli mem_cgroup_newpage_charge(pages[i], mm, 811b9bbfbe3SAndrea Arcangeli GFP_KERNEL))) { 812b9bbfbe3SAndrea Arcangeli if (pages[i]) 81371e3aac0SAndrea Arcangeli put_page(pages[i]); 814b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_start(); 815b9bbfbe3SAndrea Arcangeli while (--i >= 0) { 816b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(pages[i]); 817b9bbfbe3SAndrea Arcangeli put_page(pages[i]); 818b9bbfbe3SAndrea Arcangeli } 819b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_end(); 82071e3aac0SAndrea Arcangeli kfree(pages); 82171e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 82271e3aac0SAndrea Arcangeli goto out; 82371e3aac0SAndrea Arcangeli } 82471e3aac0SAndrea Arcangeli } 82571e3aac0SAndrea Arcangeli 82671e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 82771e3aac0SAndrea Arcangeli copy_user_highpage(pages[i], page + i, 82871e3aac0SAndrea Arcangeli haddr + PAGE_SHIFT*i, vma); 82971e3aac0SAndrea Arcangeli __SetPageUptodate(pages[i]); 83071e3aac0SAndrea Arcangeli cond_resched(); 83171e3aac0SAndrea Arcangeli } 83271e3aac0SAndrea Arcangeli 83371e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 83471e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 83571e3aac0SAndrea Arcangeli goto out_free_pages; 83671e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 83771e3aac0SAndrea Arcangeli 83871e3aac0SAndrea Arcangeli pmdp_clear_flush_notify(vma, haddr, pmd); 83971e3aac0SAndrea Arcangeli /* leave pmd empty until pte is filled */ 84071e3aac0SAndrea Arcangeli 84171e3aac0SAndrea Arcangeli pgtable = get_pmd_huge_pte(mm); 84271e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 84371e3aac0SAndrea Arcangeli 84471e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 84571e3aac0SAndrea Arcangeli pte_t *pte, entry; 84671e3aac0SAndrea Arcangeli entry = mk_pte(pages[i], vma->vm_page_prot); 84771e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 84871e3aac0SAndrea Arcangeli page_add_new_anon_rmap(pages[i], vma, haddr); 84971e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 85071e3aac0SAndrea Arcangeli VM_BUG_ON(!pte_none(*pte)); 85171e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 85271e3aac0SAndrea Arcangeli pte_unmap(pte); 85371e3aac0SAndrea Arcangeli } 85471e3aac0SAndrea Arcangeli kfree(pages); 85571e3aac0SAndrea Arcangeli 85671e3aac0SAndrea Arcangeli mm->nr_ptes++; 85771e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 85871e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 85971e3aac0SAndrea Arcangeli page_remove_rmap(page); 86071e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 86171e3aac0SAndrea Arcangeli 86271e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 86371e3aac0SAndrea Arcangeli put_page(page); 86471e3aac0SAndrea Arcangeli 86571e3aac0SAndrea Arcangeli out: 86671e3aac0SAndrea Arcangeli return ret; 86771e3aac0SAndrea Arcangeli 86871e3aac0SAndrea Arcangeli out_free_pages: 86971e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 870b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_start(); 871b9bbfbe3SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 872b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(pages[i]); 87371e3aac0SAndrea Arcangeli put_page(pages[i]); 874b9bbfbe3SAndrea Arcangeli } 875b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_end(); 87671e3aac0SAndrea Arcangeli kfree(pages); 87771e3aac0SAndrea Arcangeli goto out; 87871e3aac0SAndrea Arcangeli } 87971e3aac0SAndrea Arcangeli 88071e3aac0SAndrea Arcangeli int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 88171e3aac0SAndrea Arcangeli unsigned long address, pmd_t *pmd, pmd_t orig_pmd) 88271e3aac0SAndrea Arcangeli { 88371e3aac0SAndrea Arcangeli int ret = 0; 88471e3aac0SAndrea Arcangeli struct page *page, *new_page; 88571e3aac0SAndrea Arcangeli unsigned long haddr; 88671e3aac0SAndrea Arcangeli 88771e3aac0SAndrea Arcangeli VM_BUG_ON(!vma->anon_vma); 88871e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 88971e3aac0SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) 89071e3aac0SAndrea Arcangeli goto out_unlock; 89171e3aac0SAndrea Arcangeli 89271e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 89371e3aac0SAndrea Arcangeli VM_BUG_ON(!PageCompound(page) || !PageHead(page)); 89471e3aac0SAndrea Arcangeli haddr = address & HPAGE_PMD_MASK; 89571e3aac0SAndrea Arcangeli if (page_mapcount(page) == 1) { 89671e3aac0SAndrea Arcangeli pmd_t entry; 89771e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 89871e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 89971e3aac0SAndrea Arcangeli if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) 90071e3aac0SAndrea Arcangeli update_mmu_cache(vma, address, entry); 90171e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 90271e3aac0SAndrea Arcangeli goto out_unlock; 90371e3aac0SAndrea Arcangeli } 90471e3aac0SAndrea Arcangeli get_page(page); 90571e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 90671e3aac0SAndrea Arcangeli 90771e3aac0SAndrea Arcangeli if (transparent_hugepage_enabled(vma) && 90871e3aac0SAndrea Arcangeli !transparent_hugepage_debug_cow()) 9090bbbc0b3SAndrea Arcangeli new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), 910cc5d462fSAndi Kleen vma, haddr, numa_node_id(), 0); 91171e3aac0SAndrea Arcangeli else 91271e3aac0SAndrea Arcangeli new_page = NULL; 91371e3aac0SAndrea Arcangeli 91471e3aac0SAndrea Arcangeli if (unlikely(!new_page)) { 915*81ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 91671e3aac0SAndrea Arcangeli ret = do_huge_pmd_wp_page_fallback(mm, vma, address, 91771e3aac0SAndrea Arcangeli pmd, orig_pmd, page, haddr); 91871e3aac0SAndrea Arcangeli put_page(page); 91971e3aac0SAndrea Arcangeli goto out; 92071e3aac0SAndrea Arcangeli } 921*81ab4201SAndi Kleen count_vm_event(THP_FAULT_ALLOC); 92271e3aac0SAndrea Arcangeli 923b9bbfbe3SAndrea Arcangeli if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { 924b9bbfbe3SAndrea Arcangeli put_page(new_page); 925b9bbfbe3SAndrea Arcangeli put_page(page); 926b9bbfbe3SAndrea Arcangeli ret |= VM_FAULT_OOM; 927b9bbfbe3SAndrea Arcangeli goto out; 928b9bbfbe3SAndrea Arcangeli } 929b9bbfbe3SAndrea Arcangeli 93071e3aac0SAndrea Arcangeli copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); 93171e3aac0SAndrea Arcangeli __SetPageUptodate(new_page); 93271e3aac0SAndrea Arcangeli 93371e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 93471e3aac0SAndrea Arcangeli put_page(page); 935b9bbfbe3SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, orig_pmd))) { 936b9bbfbe3SAndrea Arcangeli mem_cgroup_uncharge_page(new_page); 93771e3aac0SAndrea Arcangeli put_page(new_page); 938b9bbfbe3SAndrea Arcangeli } else { 93971e3aac0SAndrea Arcangeli pmd_t entry; 94071e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 94171e3aac0SAndrea Arcangeli entry = mk_pmd(new_page, vma->vm_page_prot); 94271e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 94371e3aac0SAndrea Arcangeli entry = pmd_mkhuge(entry); 94471e3aac0SAndrea Arcangeli pmdp_clear_flush_notify(vma, haddr, pmd); 94571e3aac0SAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, haddr); 94671e3aac0SAndrea Arcangeli set_pmd_at(mm, haddr, pmd, entry); 94771e3aac0SAndrea Arcangeli update_mmu_cache(vma, address, entry); 94871e3aac0SAndrea Arcangeli page_remove_rmap(page); 94971e3aac0SAndrea Arcangeli put_page(page); 95071e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 95171e3aac0SAndrea Arcangeli } 95271e3aac0SAndrea Arcangeli out_unlock: 95371e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 95471e3aac0SAndrea Arcangeli out: 95571e3aac0SAndrea Arcangeli return ret; 95671e3aac0SAndrea Arcangeli } 95771e3aac0SAndrea Arcangeli 95871e3aac0SAndrea Arcangeli struct page *follow_trans_huge_pmd(struct mm_struct *mm, 95971e3aac0SAndrea Arcangeli unsigned long addr, 96071e3aac0SAndrea Arcangeli pmd_t *pmd, 96171e3aac0SAndrea Arcangeli unsigned int flags) 96271e3aac0SAndrea Arcangeli { 96371e3aac0SAndrea Arcangeli struct page *page = NULL; 96471e3aac0SAndrea Arcangeli 96571e3aac0SAndrea Arcangeli assert_spin_locked(&mm->page_table_lock); 96671e3aac0SAndrea Arcangeli 96771e3aac0SAndrea Arcangeli if (flags & FOLL_WRITE && !pmd_write(*pmd)) 96871e3aac0SAndrea Arcangeli goto out; 96971e3aac0SAndrea Arcangeli 97071e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 97171e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 97271e3aac0SAndrea Arcangeli if (flags & FOLL_TOUCH) { 97371e3aac0SAndrea Arcangeli pmd_t _pmd; 97471e3aac0SAndrea Arcangeli /* 97571e3aac0SAndrea Arcangeli * We should set the dirty bit only for FOLL_WRITE but 97671e3aac0SAndrea Arcangeli * for now the dirty bit in the pmd is meaningless. 97771e3aac0SAndrea Arcangeli * And if the dirty bit will become meaningful and 97871e3aac0SAndrea Arcangeli * we'll only set it with FOLL_WRITE, an atomic 97971e3aac0SAndrea Arcangeli * set_bit will be required on the pmd to set the 98071e3aac0SAndrea Arcangeli * young bit, instead of the current set_pmd_at. 98171e3aac0SAndrea Arcangeli */ 98271e3aac0SAndrea Arcangeli _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); 98371e3aac0SAndrea Arcangeli set_pmd_at(mm, addr & HPAGE_PMD_MASK, pmd, _pmd); 98471e3aac0SAndrea Arcangeli } 98571e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 98671e3aac0SAndrea Arcangeli VM_BUG_ON(!PageCompound(page)); 98771e3aac0SAndrea Arcangeli if (flags & FOLL_GET) 98871e3aac0SAndrea Arcangeli get_page(page); 98971e3aac0SAndrea Arcangeli 99071e3aac0SAndrea Arcangeli out: 99171e3aac0SAndrea Arcangeli return page; 99271e3aac0SAndrea Arcangeli } 99371e3aac0SAndrea Arcangeli 99471e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 99571e3aac0SAndrea Arcangeli pmd_t *pmd) 99671e3aac0SAndrea Arcangeli { 99771e3aac0SAndrea Arcangeli int ret = 0; 99871e3aac0SAndrea Arcangeli 99971e3aac0SAndrea Arcangeli spin_lock(&tlb->mm->page_table_lock); 100071e3aac0SAndrea Arcangeli if (likely(pmd_trans_huge(*pmd))) { 100171e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_splitting(*pmd))) { 100271e3aac0SAndrea Arcangeli spin_unlock(&tlb->mm->page_table_lock); 100371e3aac0SAndrea Arcangeli wait_split_huge_page(vma->anon_vma, 100471e3aac0SAndrea Arcangeli pmd); 100571e3aac0SAndrea Arcangeli } else { 100671e3aac0SAndrea Arcangeli struct page *page; 100771e3aac0SAndrea Arcangeli pgtable_t pgtable; 100871e3aac0SAndrea Arcangeli pgtable = get_pmd_huge_pte(tlb->mm); 100971e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 101071e3aac0SAndrea Arcangeli pmd_clear(pmd); 101171e3aac0SAndrea Arcangeli page_remove_rmap(page); 101271e3aac0SAndrea Arcangeli VM_BUG_ON(page_mapcount(page) < 0); 101371e3aac0SAndrea Arcangeli add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 101471e3aac0SAndrea Arcangeli VM_BUG_ON(!PageHead(page)); 101571e3aac0SAndrea Arcangeli spin_unlock(&tlb->mm->page_table_lock); 101671e3aac0SAndrea Arcangeli tlb_remove_page(tlb, page); 101771e3aac0SAndrea Arcangeli pte_free(tlb->mm, pgtable); 101871e3aac0SAndrea Arcangeli ret = 1; 101971e3aac0SAndrea Arcangeli } 102071e3aac0SAndrea Arcangeli } else 102171e3aac0SAndrea Arcangeli spin_unlock(&tlb->mm->page_table_lock); 102271e3aac0SAndrea Arcangeli 102371e3aac0SAndrea Arcangeli return ret; 102471e3aac0SAndrea Arcangeli } 102571e3aac0SAndrea Arcangeli 10260ca1634dSJohannes Weiner int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 10270ca1634dSJohannes Weiner unsigned long addr, unsigned long end, 10280ca1634dSJohannes Weiner unsigned char *vec) 10290ca1634dSJohannes Weiner { 10300ca1634dSJohannes Weiner int ret = 0; 10310ca1634dSJohannes Weiner 10320ca1634dSJohannes Weiner spin_lock(&vma->vm_mm->page_table_lock); 10330ca1634dSJohannes Weiner if (likely(pmd_trans_huge(*pmd))) { 10340ca1634dSJohannes Weiner ret = !pmd_trans_splitting(*pmd); 10350ca1634dSJohannes Weiner spin_unlock(&vma->vm_mm->page_table_lock); 10360ca1634dSJohannes Weiner if (unlikely(!ret)) 10370ca1634dSJohannes Weiner wait_split_huge_page(vma->anon_vma, pmd); 10380ca1634dSJohannes Weiner else { 10390ca1634dSJohannes Weiner /* 10400ca1634dSJohannes Weiner * All logical pages in the range are present 10410ca1634dSJohannes Weiner * if backed by a huge page. 10420ca1634dSJohannes Weiner */ 10430ca1634dSJohannes Weiner memset(vec, 1, (end - addr) >> PAGE_SHIFT); 10440ca1634dSJohannes Weiner } 10450ca1634dSJohannes Weiner } else 10460ca1634dSJohannes Weiner spin_unlock(&vma->vm_mm->page_table_lock); 10470ca1634dSJohannes Weiner 10480ca1634dSJohannes Weiner return ret; 10490ca1634dSJohannes Weiner } 10500ca1634dSJohannes Weiner 1051cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 1052cd7548abSJohannes Weiner unsigned long addr, pgprot_t newprot) 1053cd7548abSJohannes Weiner { 1054cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1055cd7548abSJohannes Weiner int ret = 0; 1056cd7548abSJohannes Weiner 1057cd7548abSJohannes Weiner spin_lock(&mm->page_table_lock); 1058cd7548abSJohannes Weiner if (likely(pmd_trans_huge(*pmd))) { 1059cd7548abSJohannes Weiner if (unlikely(pmd_trans_splitting(*pmd))) { 1060cd7548abSJohannes Weiner spin_unlock(&mm->page_table_lock); 1061cd7548abSJohannes Weiner wait_split_huge_page(vma->anon_vma, pmd); 1062cd7548abSJohannes Weiner } else { 1063cd7548abSJohannes Weiner pmd_t entry; 1064cd7548abSJohannes Weiner 1065cd7548abSJohannes Weiner entry = pmdp_get_and_clear(mm, addr, pmd); 1066cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 1067cd7548abSJohannes Weiner set_pmd_at(mm, addr, pmd, entry); 1068cd7548abSJohannes Weiner spin_unlock(&vma->vm_mm->page_table_lock); 1069cd7548abSJohannes Weiner flush_tlb_range(vma, addr, addr + HPAGE_PMD_SIZE); 1070cd7548abSJohannes Weiner ret = 1; 1071cd7548abSJohannes Weiner } 1072cd7548abSJohannes Weiner } else 1073cd7548abSJohannes Weiner spin_unlock(&vma->vm_mm->page_table_lock); 1074cd7548abSJohannes Weiner 1075cd7548abSJohannes Weiner return ret; 1076cd7548abSJohannes Weiner } 1077cd7548abSJohannes Weiner 107871e3aac0SAndrea Arcangeli pmd_t *page_check_address_pmd(struct page *page, 107971e3aac0SAndrea Arcangeli struct mm_struct *mm, 108071e3aac0SAndrea Arcangeli unsigned long address, 108171e3aac0SAndrea Arcangeli enum page_check_address_pmd_flag flag) 108271e3aac0SAndrea Arcangeli { 108371e3aac0SAndrea Arcangeli pgd_t *pgd; 108471e3aac0SAndrea Arcangeli pud_t *pud; 108571e3aac0SAndrea Arcangeli pmd_t *pmd, *ret = NULL; 108671e3aac0SAndrea Arcangeli 108771e3aac0SAndrea Arcangeli if (address & ~HPAGE_PMD_MASK) 108871e3aac0SAndrea Arcangeli goto out; 108971e3aac0SAndrea Arcangeli 109071e3aac0SAndrea Arcangeli pgd = pgd_offset(mm, address); 109171e3aac0SAndrea Arcangeli if (!pgd_present(*pgd)) 109271e3aac0SAndrea Arcangeli goto out; 109371e3aac0SAndrea Arcangeli 109471e3aac0SAndrea Arcangeli pud = pud_offset(pgd, address); 109571e3aac0SAndrea Arcangeli if (!pud_present(*pud)) 109671e3aac0SAndrea Arcangeli goto out; 109771e3aac0SAndrea Arcangeli 109871e3aac0SAndrea Arcangeli pmd = pmd_offset(pud, address); 109971e3aac0SAndrea Arcangeli if (pmd_none(*pmd)) 110071e3aac0SAndrea Arcangeli goto out; 110171e3aac0SAndrea Arcangeli if (pmd_page(*pmd) != page) 110271e3aac0SAndrea Arcangeli goto out; 110394fcc585SAndrea Arcangeli /* 110494fcc585SAndrea Arcangeli * split_vma() may create temporary aliased mappings. There is 110594fcc585SAndrea Arcangeli * no risk as long as all huge pmd are found and have their 110694fcc585SAndrea Arcangeli * splitting bit set before __split_huge_page_refcount 110794fcc585SAndrea Arcangeli * runs. Finding the same huge pmd more than once during the 110894fcc585SAndrea Arcangeli * same rmap walk is not a problem. 110994fcc585SAndrea Arcangeli */ 111094fcc585SAndrea Arcangeli if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && 111194fcc585SAndrea Arcangeli pmd_trans_splitting(*pmd)) 111294fcc585SAndrea Arcangeli goto out; 111371e3aac0SAndrea Arcangeli if (pmd_trans_huge(*pmd)) { 111471e3aac0SAndrea Arcangeli VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && 111571e3aac0SAndrea Arcangeli !pmd_trans_splitting(*pmd)); 111671e3aac0SAndrea Arcangeli ret = pmd; 111771e3aac0SAndrea Arcangeli } 111871e3aac0SAndrea Arcangeli out: 111971e3aac0SAndrea Arcangeli return ret; 112071e3aac0SAndrea Arcangeli } 112171e3aac0SAndrea Arcangeli 112271e3aac0SAndrea Arcangeli static int __split_huge_page_splitting(struct page *page, 112371e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 112471e3aac0SAndrea Arcangeli unsigned long address) 112571e3aac0SAndrea Arcangeli { 112671e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 112771e3aac0SAndrea Arcangeli pmd_t *pmd; 112871e3aac0SAndrea Arcangeli int ret = 0; 112971e3aac0SAndrea Arcangeli 113071e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 113171e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 113271e3aac0SAndrea Arcangeli PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG); 113371e3aac0SAndrea Arcangeli if (pmd) { 113471e3aac0SAndrea Arcangeli /* 113571e3aac0SAndrea Arcangeli * We can't temporarily set the pmd to null in order 113671e3aac0SAndrea Arcangeli * to split it, the pmd must remain marked huge at all 113771e3aac0SAndrea Arcangeli * times or the VM won't take the pmd_trans_huge paths 113871e3aac0SAndrea Arcangeli * and it won't wait on the anon_vma->root->lock to 113971e3aac0SAndrea Arcangeli * serialize against split_huge_page*. 114071e3aac0SAndrea Arcangeli */ 114171e3aac0SAndrea Arcangeli pmdp_splitting_flush_notify(vma, address, pmd); 114271e3aac0SAndrea Arcangeli ret = 1; 114371e3aac0SAndrea Arcangeli } 114471e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 114571e3aac0SAndrea Arcangeli 114671e3aac0SAndrea Arcangeli return ret; 114771e3aac0SAndrea Arcangeli } 114871e3aac0SAndrea Arcangeli 114971e3aac0SAndrea Arcangeli static void __split_huge_page_refcount(struct page *page) 115071e3aac0SAndrea Arcangeli { 115171e3aac0SAndrea Arcangeli int i; 115271e3aac0SAndrea Arcangeli unsigned long head_index = page->index; 115371e3aac0SAndrea Arcangeli struct zone *zone = page_zone(page); 11542c888cfbSRik van Riel int zonestat; 115571e3aac0SAndrea Arcangeli 115671e3aac0SAndrea Arcangeli /* prevent PageLRU to go away from under us, and freeze lru stats */ 115771e3aac0SAndrea Arcangeli spin_lock_irq(&zone->lru_lock); 115871e3aac0SAndrea Arcangeli compound_lock(page); 115971e3aac0SAndrea Arcangeli 116071e3aac0SAndrea Arcangeli for (i = 1; i < HPAGE_PMD_NR; i++) { 116171e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 116271e3aac0SAndrea Arcangeli 116371e3aac0SAndrea Arcangeli /* tail_page->_count cannot change */ 116471e3aac0SAndrea Arcangeli atomic_sub(atomic_read(&page_tail->_count), &page->_count); 116571e3aac0SAndrea Arcangeli BUG_ON(page_count(page) <= 0); 116671e3aac0SAndrea Arcangeli atomic_add(page_mapcount(page) + 1, &page_tail->_count); 116771e3aac0SAndrea Arcangeli BUG_ON(atomic_read(&page_tail->_count) <= 0); 116871e3aac0SAndrea Arcangeli 116971e3aac0SAndrea Arcangeli /* after clearing PageTail the gup refcount can be released */ 117071e3aac0SAndrea Arcangeli smp_mb(); 117171e3aac0SAndrea Arcangeli 1172a6d30dddSJin Dongming /* 1173a6d30dddSJin Dongming * retain hwpoison flag of the poisoned tail page: 1174a6d30dddSJin Dongming * fix for the unsuitable process killed on Guest Machine(KVM) 1175a6d30dddSJin Dongming * by the memory-failure. 1176a6d30dddSJin Dongming */ 1177a6d30dddSJin Dongming page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; 117871e3aac0SAndrea Arcangeli page_tail->flags |= (page->flags & 117971e3aac0SAndrea Arcangeli ((1L << PG_referenced) | 118071e3aac0SAndrea Arcangeli (1L << PG_swapbacked) | 118171e3aac0SAndrea Arcangeli (1L << PG_mlocked) | 118271e3aac0SAndrea Arcangeli (1L << PG_uptodate))); 118371e3aac0SAndrea Arcangeli page_tail->flags |= (1L << PG_dirty); 118471e3aac0SAndrea Arcangeli 118571e3aac0SAndrea Arcangeli /* 118671e3aac0SAndrea Arcangeli * 1) clear PageTail before overwriting first_page 118771e3aac0SAndrea Arcangeli * 2) clear PageTail before clearing PageHead for VM_BUG_ON 118871e3aac0SAndrea Arcangeli */ 118971e3aac0SAndrea Arcangeli smp_wmb(); 119071e3aac0SAndrea Arcangeli 119171e3aac0SAndrea Arcangeli /* 119271e3aac0SAndrea Arcangeli * __split_huge_page_splitting() already set the 119371e3aac0SAndrea Arcangeli * splitting bit in all pmd that could map this 119471e3aac0SAndrea Arcangeli * hugepage, that will ensure no CPU can alter the 119571e3aac0SAndrea Arcangeli * mapcount on the head page. The mapcount is only 119671e3aac0SAndrea Arcangeli * accounted in the head page and it has to be 119771e3aac0SAndrea Arcangeli * transferred to all tail pages in the below code. So 119871e3aac0SAndrea Arcangeli * for this code to be safe, the split the mapcount 119971e3aac0SAndrea Arcangeli * can't change. But that doesn't mean userland can't 120071e3aac0SAndrea Arcangeli * keep changing and reading the page contents while 120171e3aac0SAndrea Arcangeli * we transfer the mapcount, so the pmd splitting 120271e3aac0SAndrea Arcangeli * status is achieved setting a reserved bit in the 120371e3aac0SAndrea Arcangeli * pmd, not by clearing the present bit. 120471e3aac0SAndrea Arcangeli */ 120571e3aac0SAndrea Arcangeli BUG_ON(page_mapcount(page_tail)); 120671e3aac0SAndrea Arcangeli page_tail->_mapcount = page->_mapcount; 120771e3aac0SAndrea Arcangeli 120871e3aac0SAndrea Arcangeli BUG_ON(page_tail->mapping); 120971e3aac0SAndrea Arcangeli page_tail->mapping = page->mapping; 121071e3aac0SAndrea Arcangeli 121171e3aac0SAndrea Arcangeli page_tail->index = ++head_index; 121271e3aac0SAndrea Arcangeli 121371e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page_tail)); 121471e3aac0SAndrea Arcangeli BUG_ON(!PageUptodate(page_tail)); 121571e3aac0SAndrea Arcangeli BUG_ON(!PageDirty(page_tail)); 121671e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page_tail)); 121771e3aac0SAndrea Arcangeli 1218ca3e0214SKAMEZAWA Hiroyuki mem_cgroup_split_huge_fixup(page, page_tail); 1219ca3e0214SKAMEZAWA Hiroyuki 122071e3aac0SAndrea Arcangeli lru_add_page_tail(zone, page, page_tail); 122171e3aac0SAndrea Arcangeli } 122271e3aac0SAndrea Arcangeli 122379134171SAndrea Arcangeli __dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES); 122479134171SAndrea Arcangeli __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR); 122579134171SAndrea Arcangeli 12262c888cfbSRik van Riel /* 12272c888cfbSRik van Riel * A hugepage counts for HPAGE_PMD_NR pages on the LRU statistics, 12282c888cfbSRik van Riel * so adjust those appropriately if this page is on the LRU. 12292c888cfbSRik van Riel */ 12302c888cfbSRik van Riel if (PageLRU(page)) { 12312c888cfbSRik van Riel zonestat = NR_LRU_BASE + page_lru(page); 12322c888cfbSRik van Riel __mod_zone_page_state(zone, zonestat, -(HPAGE_PMD_NR-1)); 12332c888cfbSRik van Riel } 12342c888cfbSRik van Riel 123571e3aac0SAndrea Arcangeli ClearPageCompound(page); 123671e3aac0SAndrea Arcangeli compound_unlock(page); 123771e3aac0SAndrea Arcangeli spin_unlock_irq(&zone->lru_lock); 123871e3aac0SAndrea Arcangeli 123971e3aac0SAndrea Arcangeli for (i = 1; i < HPAGE_PMD_NR; i++) { 124071e3aac0SAndrea Arcangeli struct page *page_tail = page + i; 124171e3aac0SAndrea Arcangeli BUG_ON(page_count(page_tail) <= 0); 124271e3aac0SAndrea Arcangeli /* 124371e3aac0SAndrea Arcangeli * Tail pages may be freed if there wasn't any mapping 124471e3aac0SAndrea Arcangeli * like if add_to_swap() is running on a lru page that 124571e3aac0SAndrea Arcangeli * had its mapping zapped. And freeing these pages 124671e3aac0SAndrea Arcangeli * requires taking the lru_lock so we do the put_page 124771e3aac0SAndrea Arcangeli * of the tail pages after the split is complete. 124871e3aac0SAndrea Arcangeli */ 124971e3aac0SAndrea Arcangeli put_page(page_tail); 125071e3aac0SAndrea Arcangeli } 125171e3aac0SAndrea Arcangeli 125271e3aac0SAndrea Arcangeli /* 125371e3aac0SAndrea Arcangeli * Only the head page (now become a regular page) is required 125471e3aac0SAndrea Arcangeli * to be pinned by the caller. 125571e3aac0SAndrea Arcangeli */ 125671e3aac0SAndrea Arcangeli BUG_ON(page_count(page) <= 0); 125771e3aac0SAndrea Arcangeli } 125871e3aac0SAndrea Arcangeli 125971e3aac0SAndrea Arcangeli static int __split_huge_page_map(struct page *page, 126071e3aac0SAndrea Arcangeli struct vm_area_struct *vma, 126171e3aac0SAndrea Arcangeli unsigned long address) 126271e3aac0SAndrea Arcangeli { 126371e3aac0SAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 126471e3aac0SAndrea Arcangeli pmd_t *pmd, _pmd; 126571e3aac0SAndrea Arcangeli int ret = 0, i; 126671e3aac0SAndrea Arcangeli pgtable_t pgtable; 126771e3aac0SAndrea Arcangeli unsigned long haddr; 126871e3aac0SAndrea Arcangeli 126971e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 127071e3aac0SAndrea Arcangeli pmd = page_check_address_pmd(page, mm, address, 127171e3aac0SAndrea Arcangeli PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); 127271e3aac0SAndrea Arcangeli if (pmd) { 127371e3aac0SAndrea Arcangeli pgtable = get_pmd_huge_pte(mm); 127471e3aac0SAndrea Arcangeli pmd_populate(mm, &_pmd, pgtable); 127571e3aac0SAndrea Arcangeli 127671e3aac0SAndrea Arcangeli for (i = 0, haddr = address; i < HPAGE_PMD_NR; 127771e3aac0SAndrea Arcangeli i++, haddr += PAGE_SIZE) { 127871e3aac0SAndrea Arcangeli pte_t *pte, entry; 127971e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page+i)); 128071e3aac0SAndrea Arcangeli entry = mk_pte(page + i, vma->vm_page_prot); 128171e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 128271e3aac0SAndrea Arcangeli if (!pmd_write(*pmd)) 128371e3aac0SAndrea Arcangeli entry = pte_wrprotect(entry); 128471e3aac0SAndrea Arcangeli else 128571e3aac0SAndrea Arcangeli BUG_ON(page_mapcount(page) != 1); 128671e3aac0SAndrea Arcangeli if (!pmd_young(*pmd)) 128771e3aac0SAndrea Arcangeli entry = pte_mkold(entry); 128871e3aac0SAndrea Arcangeli pte = pte_offset_map(&_pmd, haddr); 128971e3aac0SAndrea Arcangeli BUG_ON(!pte_none(*pte)); 129071e3aac0SAndrea Arcangeli set_pte_at(mm, haddr, pte, entry); 129171e3aac0SAndrea Arcangeli pte_unmap(pte); 129271e3aac0SAndrea Arcangeli } 129371e3aac0SAndrea Arcangeli 129471e3aac0SAndrea Arcangeli mm->nr_ptes++; 129571e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 129671e3aac0SAndrea Arcangeli /* 129771e3aac0SAndrea Arcangeli * Up to this point the pmd is present and huge and 129871e3aac0SAndrea Arcangeli * userland has the whole access to the hugepage 129971e3aac0SAndrea Arcangeli * during the split (which happens in place). If we 130071e3aac0SAndrea Arcangeli * overwrite the pmd with the not-huge version 130171e3aac0SAndrea Arcangeli * pointing to the pte here (which of course we could 130271e3aac0SAndrea Arcangeli * if all CPUs were bug free), userland could trigger 130371e3aac0SAndrea Arcangeli * a small page size TLB miss on the small sized TLB 130471e3aac0SAndrea Arcangeli * while the hugepage TLB entry is still established 130571e3aac0SAndrea Arcangeli * in the huge TLB. Some CPU doesn't like that. See 130671e3aac0SAndrea Arcangeli * http://support.amd.com/us/Processor_TechDocs/41322.pdf, 130771e3aac0SAndrea Arcangeli * Erratum 383 on page 93. Intel should be safe but is 130871e3aac0SAndrea Arcangeli * also warns that it's only safe if the permission 130971e3aac0SAndrea Arcangeli * and cache attributes of the two entries loaded in 131071e3aac0SAndrea Arcangeli * the two TLB is identical (which should be the case 131171e3aac0SAndrea Arcangeli * here). But it is generally safer to never allow 131271e3aac0SAndrea Arcangeli * small and huge TLB entries for the same virtual 131371e3aac0SAndrea Arcangeli * address to be loaded simultaneously. So instead of 131471e3aac0SAndrea Arcangeli * doing "pmd_populate(); flush_tlb_range();" we first 131571e3aac0SAndrea Arcangeli * mark the current pmd notpresent (atomically because 131671e3aac0SAndrea Arcangeli * here the pmd_trans_huge and pmd_trans_splitting 131771e3aac0SAndrea Arcangeli * must remain set at all times on the pmd until the 131871e3aac0SAndrea Arcangeli * split is complete for this pmd), then we flush the 131971e3aac0SAndrea Arcangeli * SMP TLB and finally we write the non-huge version 132071e3aac0SAndrea Arcangeli * of the pmd entry with pmd_populate. 132171e3aac0SAndrea Arcangeli */ 132271e3aac0SAndrea Arcangeli set_pmd_at(mm, address, pmd, pmd_mknotpresent(*pmd)); 132371e3aac0SAndrea Arcangeli flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 132471e3aac0SAndrea Arcangeli pmd_populate(mm, pmd, pgtable); 132571e3aac0SAndrea Arcangeli ret = 1; 132671e3aac0SAndrea Arcangeli } 132771e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 132871e3aac0SAndrea Arcangeli 132971e3aac0SAndrea Arcangeli return ret; 133071e3aac0SAndrea Arcangeli } 133171e3aac0SAndrea Arcangeli 133271e3aac0SAndrea Arcangeli /* must be called with anon_vma->root->lock hold */ 133371e3aac0SAndrea Arcangeli static void __split_huge_page(struct page *page, 133471e3aac0SAndrea Arcangeli struct anon_vma *anon_vma) 133571e3aac0SAndrea Arcangeli { 133671e3aac0SAndrea Arcangeli int mapcount, mapcount2; 133771e3aac0SAndrea Arcangeli struct anon_vma_chain *avc; 133871e3aac0SAndrea Arcangeli 133971e3aac0SAndrea Arcangeli BUG_ON(!PageHead(page)); 134071e3aac0SAndrea Arcangeli BUG_ON(PageTail(page)); 134171e3aac0SAndrea Arcangeli 134271e3aac0SAndrea Arcangeli mapcount = 0; 134371e3aac0SAndrea Arcangeli list_for_each_entry(avc, &anon_vma->head, same_anon_vma) { 134471e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 134571e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 134671e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 134771e3aac0SAndrea Arcangeli if (addr == -EFAULT) 134871e3aac0SAndrea Arcangeli continue; 134971e3aac0SAndrea Arcangeli mapcount += __split_huge_page_splitting(page, vma, addr); 135071e3aac0SAndrea Arcangeli } 135105759d38SAndrea Arcangeli /* 135205759d38SAndrea Arcangeli * It is critical that new vmas are added to the tail of the 135305759d38SAndrea Arcangeli * anon_vma list. This guarantes that if copy_huge_pmd() runs 135405759d38SAndrea Arcangeli * and establishes a child pmd before 135505759d38SAndrea Arcangeli * __split_huge_page_splitting() freezes the parent pmd (so if 135605759d38SAndrea Arcangeli * we fail to prevent copy_huge_pmd() from running until the 135705759d38SAndrea Arcangeli * whole __split_huge_page() is complete), we will still see 135805759d38SAndrea Arcangeli * the newly established pmd of the child later during the 135905759d38SAndrea Arcangeli * walk, to be able to set it as pmd_trans_splitting too. 136005759d38SAndrea Arcangeli */ 136105759d38SAndrea Arcangeli if (mapcount != page_mapcount(page)) 136205759d38SAndrea Arcangeli printk(KERN_ERR "mapcount %d page_mapcount %d\n", 136305759d38SAndrea Arcangeli mapcount, page_mapcount(page)); 136471e3aac0SAndrea Arcangeli BUG_ON(mapcount != page_mapcount(page)); 136571e3aac0SAndrea Arcangeli 136671e3aac0SAndrea Arcangeli __split_huge_page_refcount(page); 136771e3aac0SAndrea Arcangeli 136871e3aac0SAndrea Arcangeli mapcount2 = 0; 136971e3aac0SAndrea Arcangeli list_for_each_entry(avc, &anon_vma->head, same_anon_vma) { 137071e3aac0SAndrea Arcangeli struct vm_area_struct *vma = avc->vma; 137171e3aac0SAndrea Arcangeli unsigned long addr = vma_address(page, vma); 137271e3aac0SAndrea Arcangeli BUG_ON(is_vma_temporary_stack(vma)); 137371e3aac0SAndrea Arcangeli if (addr == -EFAULT) 137471e3aac0SAndrea Arcangeli continue; 137571e3aac0SAndrea Arcangeli mapcount2 += __split_huge_page_map(page, vma, addr); 137671e3aac0SAndrea Arcangeli } 137705759d38SAndrea Arcangeli if (mapcount != mapcount2) 137805759d38SAndrea Arcangeli printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", 137905759d38SAndrea Arcangeli mapcount, mapcount2, page_mapcount(page)); 138071e3aac0SAndrea Arcangeli BUG_ON(mapcount != mapcount2); 138171e3aac0SAndrea Arcangeli } 138271e3aac0SAndrea Arcangeli 138371e3aac0SAndrea Arcangeli int split_huge_page(struct page *page) 138471e3aac0SAndrea Arcangeli { 138571e3aac0SAndrea Arcangeli struct anon_vma *anon_vma; 138671e3aac0SAndrea Arcangeli int ret = 1; 138771e3aac0SAndrea Arcangeli 138871e3aac0SAndrea Arcangeli BUG_ON(!PageAnon(page)); 138971e3aac0SAndrea Arcangeli anon_vma = page_lock_anon_vma(page); 139071e3aac0SAndrea Arcangeli if (!anon_vma) 139171e3aac0SAndrea Arcangeli goto out; 139271e3aac0SAndrea Arcangeli ret = 0; 139371e3aac0SAndrea Arcangeli if (!PageCompound(page)) 139471e3aac0SAndrea Arcangeli goto out_unlock; 139571e3aac0SAndrea Arcangeli 139671e3aac0SAndrea Arcangeli BUG_ON(!PageSwapBacked(page)); 139771e3aac0SAndrea Arcangeli __split_huge_page(page, anon_vma); 1398*81ab4201SAndi Kleen count_vm_event(THP_SPLIT); 139971e3aac0SAndrea Arcangeli 140071e3aac0SAndrea Arcangeli BUG_ON(PageCompound(page)); 140171e3aac0SAndrea Arcangeli out_unlock: 140271e3aac0SAndrea Arcangeli page_unlock_anon_vma(anon_vma); 140371e3aac0SAndrea Arcangeli out: 140471e3aac0SAndrea Arcangeli return ret; 140571e3aac0SAndrea Arcangeli } 140671e3aac0SAndrea Arcangeli 140760ab3244SAndrea Arcangeli int hugepage_madvise(struct vm_area_struct *vma, 140860ab3244SAndrea Arcangeli unsigned long *vm_flags, int advice) 14090af4e98bSAndrea Arcangeli { 1410a664b2d8SAndrea Arcangeli switch (advice) { 1411a664b2d8SAndrea Arcangeli case MADV_HUGEPAGE: 14120af4e98bSAndrea Arcangeli /* 14130af4e98bSAndrea Arcangeli * Be somewhat over-protective like KSM for now! 14140af4e98bSAndrea Arcangeli */ 1415a664b2d8SAndrea Arcangeli if (*vm_flags & (VM_HUGEPAGE | 1416a664b2d8SAndrea Arcangeli VM_SHARED | VM_MAYSHARE | 14170af4e98bSAndrea Arcangeli VM_PFNMAP | VM_IO | VM_DONTEXPAND | 14180af4e98bSAndrea Arcangeli VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE | 14190af4e98bSAndrea Arcangeli VM_MIXEDMAP | VM_SAO)) 14200af4e98bSAndrea Arcangeli return -EINVAL; 1421a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_NOHUGEPAGE; 14220af4e98bSAndrea Arcangeli *vm_flags |= VM_HUGEPAGE; 142360ab3244SAndrea Arcangeli /* 142460ab3244SAndrea Arcangeli * If the vma become good for khugepaged to scan, 142560ab3244SAndrea Arcangeli * register it here without waiting a page fault that 142660ab3244SAndrea Arcangeli * may not happen any time soon. 142760ab3244SAndrea Arcangeli */ 142860ab3244SAndrea Arcangeli if (unlikely(khugepaged_enter_vma_merge(vma))) 142960ab3244SAndrea Arcangeli return -ENOMEM; 1430a664b2d8SAndrea Arcangeli break; 1431a664b2d8SAndrea Arcangeli case MADV_NOHUGEPAGE: 1432a664b2d8SAndrea Arcangeli /* 1433a664b2d8SAndrea Arcangeli * Be somewhat over-protective like KSM for now! 1434a664b2d8SAndrea Arcangeli */ 1435a664b2d8SAndrea Arcangeli if (*vm_flags & (VM_NOHUGEPAGE | 1436a664b2d8SAndrea Arcangeli VM_SHARED | VM_MAYSHARE | 1437a664b2d8SAndrea Arcangeli VM_PFNMAP | VM_IO | VM_DONTEXPAND | 1438a664b2d8SAndrea Arcangeli VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE | 1439a664b2d8SAndrea Arcangeli VM_MIXEDMAP | VM_SAO)) 1440a664b2d8SAndrea Arcangeli return -EINVAL; 1441a664b2d8SAndrea Arcangeli *vm_flags &= ~VM_HUGEPAGE; 1442a664b2d8SAndrea Arcangeli *vm_flags |= VM_NOHUGEPAGE; 144360ab3244SAndrea Arcangeli /* 144460ab3244SAndrea Arcangeli * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning 144560ab3244SAndrea Arcangeli * this vma even if we leave the mm registered in khugepaged if 144660ab3244SAndrea Arcangeli * it got registered before VM_NOHUGEPAGE was set. 144760ab3244SAndrea Arcangeli */ 1448a664b2d8SAndrea Arcangeli break; 1449a664b2d8SAndrea Arcangeli } 14500af4e98bSAndrea Arcangeli 14510af4e98bSAndrea Arcangeli return 0; 14520af4e98bSAndrea Arcangeli } 14530af4e98bSAndrea Arcangeli 1454ba76149fSAndrea Arcangeli static int __init khugepaged_slab_init(void) 1455ba76149fSAndrea Arcangeli { 1456ba76149fSAndrea Arcangeli mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", 1457ba76149fSAndrea Arcangeli sizeof(struct mm_slot), 1458ba76149fSAndrea Arcangeli __alignof__(struct mm_slot), 0, NULL); 1459ba76149fSAndrea Arcangeli if (!mm_slot_cache) 1460ba76149fSAndrea Arcangeli return -ENOMEM; 1461ba76149fSAndrea Arcangeli 1462ba76149fSAndrea Arcangeli return 0; 1463ba76149fSAndrea Arcangeli } 1464ba76149fSAndrea Arcangeli 1465ba76149fSAndrea Arcangeli static void __init khugepaged_slab_free(void) 1466ba76149fSAndrea Arcangeli { 1467ba76149fSAndrea Arcangeli kmem_cache_destroy(mm_slot_cache); 1468ba76149fSAndrea Arcangeli mm_slot_cache = NULL; 1469ba76149fSAndrea Arcangeli } 1470ba76149fSAndrea Arcangeli 1471ba76149fSAndrea Arcangeli static inline struct mm_slot *alloc_mm_slot(void) 1472ba76149fSAndrea Arcangeli { 1473ba76149fSAndrea Arcangeli if (!mm_slot_cache) /* initialization failed */ 1474ba76149fSAndrea Arcangeli return NULL; 1475ba76149fSAndrea Arcangeli return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); 1476ba76149fSAndrea Arcangeli } 1477ba76149fSAndrea Arcangeli 1478ba76149fSAndrea Arcangeli static inline void free_mm_slot(struct mm_slot *mm_slot) 1479ba76149fSAndrea Arcangeli { 1480ba76149fSAndrea Arcangeli kmem_cache_free(mm_slot_cache, mm_slot); 1481ba76149fSAndrea Arcangeli } 1482ba76149fSAndrea Arcangeli 1483ba76149fSAndrea Arcangeli static int __init mm_slots_hash_init(void) 1484ba76149fSAndrea Arcangeli { 1485ba76149fSAndrea Arcangeli mm_slots_hash = kzalloc(MM_SLOTS_HASH_HEADS * sizeof(struct hlist_head), 1486ba76149fSAndrea Arcangeli GFP_KERNEL); 1487ba76149fSAndrea Arcangeli if (!mm_slots_hash) 1488ba76149fSAndrea Arcangeli return -ENOMEM; 1489ba76149fSAndrea Arcangeli return 0; 1490ba76149fSAndrea Arcangeli } 1491ba76149fSAndrea Arcangeli 1492ba76149fSAndrea Arcangeli #if 0 1493ba76149fSAndrea Arcangeli static void __init mm_slots_hash_free(void) 1494ba76149fSAndrea Arcangeli { 1495ba76149fSAndrea Arcangeli kfree(mm_slots_hash); 1496ba76149fSAndrea Arcangeli mm_slots_hash = NULL; 1497ba76149fSAndrea Arcangeli } 1498ba76149fSAndrea Arcangeli #endif 1499ba76149fSAndrea Arcangeli 1500ba76149fSAndrea Arcangeli static struct mm_slot *get_mm_slot(struct mm_struct *mm) 1501ba76149fSAndrea Arcangeli { 1502ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1503ba76149fSAndrea Arcangeli struct hlist_head *bucket; 1504ba76149fSAndrea Arcangeli struct hlist_node *node; 1505ba76149fSAndrea Arcangeli 1506ba76149fSAndrea Arcangeli bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) 1507ba76149fSAndrea Arcangeli % MM_SLOTS_HASH_HEADS]; 1508ba76149fSAndrea Arcangeli hlist_for_each_entry(mm_slot, node, bucket, hash) { 1509ba76149fSAndrea Arcangeli if (mm == mm_slot->mm) 1510ba76149fSAndrea Arcangeli return mm_slot; 1511ba76149fSAndrea Arcangeli } 1512ba76149fSAndrea Arcangeli return NULL; 1513ba76149fSAndrea Arcangeli } 1514ba76149fSAndrea Arcangeli 1515ba76149fSAndrea Arcangeli static void insert_to_mm_slots_hash(struct mm_struct *mm, 1516ba76149fSAndrea Arcangeli struct mm_slot *mm_slot) 1517ba76149fSAndrea Arcangeli { 1518ba76149fSAndrea Arcangeli struct hlist_head *bucket; 1519ba76149fSAndrea Arcangeli 1520ba76149fSAndrea Arcangeli bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) 1521ba76149fSAndrea Arcangeli % MM_SLOTS_HASH_HEADS]; 1522ba76149fSAndrea Arcangeli mm_slot->mm = mm; 1523ba76149fSAndrea Arcangeli hlist_add_head(&mm_slot->hash, bucket); 1524ba76149fSAndrea Arcangeli } 1525ba76149fSAndrea Arcangeli 1526ba76149fSAndrea Arcangeli static inline int khugepaged_test_exit(struct mm_struct *mm) 1527ba76149fSAndrea Arcangeli { 1528ba76149fSAndrea Arcangeli return atomic_read(&mm->mm_users) == 0; 1529ba76149fSAndrea Arcangeli } 1530ba76149fSAndrea Arcangeli 1531ba76149fSAndrea Arcangeli int __khugepaged_enter(struct mm_struct *mm) 1532ba76149fSAndrea Arcangeli { 1533ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1534ba76149fSAndrea Arcangeli int wakeup; 1535ba76149fSAndrea Arcangeli 1536ba76149fSAndrea Arcangeli mm_slot = alloc_mm_slot(); 1537ba76149fSAndrea Arcangeli if (!mm_slot) 1538ba76149fSAndrea Arcangeli return -ENOMEM; 1539ba76149fSAndrea Arcangeli 1540ba76149fSAndrea Arcangeli /* __khugepaged_exit() must not run from under us */ 1541ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_test_exit(mm)); 1542ba76149fSAndrea Arcangeli if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { 1543ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 1544ba76149fSAndrea Arcangeli return 0; 1545ba76149fSAndrea Arcangeli } 1546ba76149fSAndrea Arcangeli 1547ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 1548ba76149fSAndrea Arcangeli insert_to_mm_slots_hash(mm, mm_slot); 1549ba76149fSAndrea Arcangeli /* 1550ba76149fSAndrea Arcangeli * Insert just behind the scanning cursor, to let the area settle 1551ba76149fSAndrea Arcangeli * down a little. 1552ba76149fSAndrea Arcangeli */ 1553ba76149fSAndrea Arcangeli wakeup = list_empty(&khugepaged_scan.mm_head); 1554ba76149fSAndrea Arcangeli list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); 1555ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 1556ba76149fSAndrea Arcangeli 1557ba76149fSAndrea Arcangeli atomic_inc(&mm->mm_count); 1558ba76149fSAndrea Arcangeli if (wakeup) 1559ba76149fSAndrea Arcangeli wake_up_interruptible(&khugepaged_wait); 1560ba76149fSAndrea Arcangeli 1561ba76149fSAndrea Arcangeli return 0; 1562ba76149fSAndrea Arcangeli } 1563ba76149fSAndrea Arcangeli 1564ba76149fSAndrea Arcangeli int khugepaged_enter_vma_merge(struct vm_area_struct *vma) 1565ba76149fSAndrea Arcangeli { 1566ba76149fSAndrea Arcangeli unsigned long hstart, hend; 1567ba76149fSAndrea Arcangeli if (!vma->anon_vma) 1568ba76149fSAndrea Arcangeli /* 1569ba76149fSAndrea Arcangeli * Not yet faulted in so we will register later in the 1570ba76149fSAndrea Arcangeli * page fault if needed. 1571ba76149fSAndrea Arcangeli */ 1572ba76149fSAndrea Arcangeli return 0; 1573ba76149fSAndrea Arcangeli if (vma->vm_file || vma->vm_ops) 1574ba76149fSAndrea Arcangeli /* khugepaged not yet working on file or special mappings */ 1575ba76149fSAndrea Arcangeli return 0; 1576ba76149fSAndrea Arcangeli VM_BUG_ON(is_linear_pfn_mapping(vma) || is_pfn_mapping(vma)); 1577ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 1578ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 1579ba76149fSAndrea Arcangeli if (hstart < hend) 1580ba76149fSAndrea Arcangeli return khugepaged_enter(vma); 1581ba76149fSAndrea Arcangeli return 0; 1582ba76149fSAndrea Arcangeli } 1583ba76149fSAndrea Arcangeli 1584ba76149fSAndrea Arcangeli void __khugepaged_exit(struct mm_struct *mm) 1585ba76149fSAndrea Arcangeli { 1586ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 1587ba76149fSAndrea Arcangeli int free = 0; 1588ba76149fSAndrea Arcangeli 1589ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 1590ba76149fSAndrea Arcangeli mm_slot = get_mm_slot(mm); 1591ba76149fSAndrea Arcangeli if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { 1592ba76149fSAndrea Arcangeli hlist_del(&mm_slot->hash); 1593ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 1594ba76149fSAndrea Arcangeli free = 1; 1595ba76149fSAndrea Arcangeli } 1596ba76149fSAndrea Arcangeli 1597ba76149fSAndrea Arcangeli if (free) { 1598ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 1599ba76149fSAndrea Arcangeli clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 1600ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 1601ba76149fSAndrea Arcangeli mmdrop(mm); 1602ba76149fSAndrea Arcangeli } else if (mm_slot) { 1603ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 1604ba76149fSAndrea Arcangeli /* 1605ba76149fSAndrea Arcangeli * This is required to serialize against 1606ba76149fSAndrea Arcangeli * khugepaged_test_exit() (which is guaranteed to run 1607ba76149fSAndrea Arcangeli * under mmap sem read mode). Stop here (after we 1608ba76149fSAndrea Arcangeli * return all pagetables will be destroyed) until 1609ba76149fSAndrea Arcangeli * khugepaged has finished working on the pagetables 1610ba76149fSAndrea Arcangeli * under the mmap_sem. 1611ba76149fSAndrea Arcangeli */ 1612ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 1613ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 1614ba76149fSAndrea Arcangeli } else 1615ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 1616ba76149fSAndrea Arcangeli } 1617ba76149fSAndrea Arcangeli 1618ba76149fSAndrea Arcangeli static void release_pte_page(struct page *page) 1619ba76149fSAndrea Arcangeli { 1620ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 1621ba76149fSAndrea Arcangeli dec_zone_page_state(page, NR_ISOLATED_ANON + 0); 1622ba76149fSAndrea Arcangeli unlock_page(page); 1623ba76149fSAndrea Arcangeli putback_lru_page(page); 1624ba76149fSAndrea Arcangeli } 1625ba76149fSAndrea Arcangeli 1626ba76149fSAndrea Arcangeli static void release_pte_pages(pte_t *pte, pte_t *_pte) 1627ba76149fSAndrea Arcangeli { 1628ba76149fSAndrea Arcangeli while (--_pte >= pte) { 1629ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 1630ba76149fSAndrea Arcangeli if (!pte_none(pteval)) 1631ba76149fSAndrea Arcangeli release_pte_page(pte_page(pteval)); 1632ba76149fSAndrea Arcangeli } 1633ba76149fSAndrea Arcangeli } 1634ba76149fSAndrea Arcangeli 1635ba76149fSAndrea Arcangeli static void release_all_pte_pages(pte_t *pte) 1636ba76149fSAndrea Arcangeli { 1637ba76149fSAndrea Arcangeli release_pte_pages(pte, pte + HPAGE_PMD_NR); 1638ba76149fSAndrea Arcangeli } 1639ba76149fSAndrea Arcangeli 1640ba76149fSAndrea Arcangeli static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 1641ba76149fSAndrea Arcangeli unsigned long address, 1642ba76149fSAndrea Arcangeli pte_t *pte) 1643ba76149fSAndrea Arcangeli { 1644ba76149fSAndrea Arcangeli struct page *page; 1645ba76149fSAndrea Arcangeli pte_t *_pte; 1646ba76149fSAndrea Arcangeli int referenced = 0, isolated = 0, none = 0; 1647ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; 1648ba76149fSAndrea Arcangeli _pte++, address += PAGE_SIZE) { 1649ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 1650ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 1651ba76149fSAndrea Arcangeli if (++none <= khugepaged_max_ptes_none) 1652ba76149fSAndrea Arcangeli continue; 1653ba76149fSAndrea Arcangeli else { 1654ba76149fSAndrea Arcangeli release_pte_pages(pte, _pte); 1655ba76149fSAndrea Arcangeli goto out; 1656ba76149fSAndrea Arcangeli } 1657ba76149fSAndrea Arcangeli } 1658ba76149fSAndrea Arcangeli if (!pte_present(pteval) || !pte_write(pteval)) { 1659ba76149fSAndrea Arcangeli release_pte_pages(pte, _pte); 1660ba76149fSAndrea Arcangeli goto out; 1661ba76149fSAndrea Arcangeli } 1662ba76149fSAndrea Arcangeli page = vm_normal_page(vma, address, pteval); 1663ba76149fSAndrea Arcangeli if (unlikely(!page)) { 1664ba76149fSAndrea Arcangeli release_pte_pages(pte, _pte); 1665ba76149fSAndrea Arcangeli goto out; 1666ba76149fSAndrea Arcangeli } 1667ba76149fSAndrea Arcangeli VM_BUG_ON(PageCompound(page)); 1668ba76149fSAndrea Arcangeli BUG_ON(!PageAnon(page)); 1669ba76149fSAndrea Arcangeli VM_BUG_ON(!PageSwapBacked(page)); 1670ba76149fSAndrea Arcangeli 1671ba76149fSAndrea Arcangeli /* cannot use mapcount: can't collapse if there's a gup pin */ 1672ba76149fSAndrea Arcangeli if (page_count(page) != 1) { 1673ba76149fSAndrea Arcangeli release_pte_pages(pte, _pte); 1674ba76149fSAndrea Arcangeli goto out; 1675ba76149fSAndrea Arcangeli } 1676ba76149fSAndrea Arcangeli /* 1677ba76149fSAndrea Arcangeli * We can do it before isolate_lru_page because the 1678ba76149fSAndrea Arcangeli * page can't be freed from under us. NOTE: PG_lock 1679ba76149fSAndrea Arcangeli * is needed to serialize against split_huge_page 1680ba76149fSAndrea Arcangeli * when invoked from the VM. 1681ba76149fSAndrea Arcangeli */ 1682ba76149fSAndrea Arcangeli if (!trylock_page(page)) { 1683ba76149fSAndrea Arcangeli release_pte_pages(pte, _pte); 1684ba76149fSAndrea Arcangeli goto out; 1685ba76149fSAndrea Arcangeli } 1686ba76149fSAndrea Arcangeli /* 1687ba76149fSAndrea Arcangeli * Isolate the page to avoid collapsing an hugepage 1688ba76149fSAndrea Arcangeli * currently in use by the VM. 1689ba76149fSAndrea Arcangeli */ 1690ba76149fSAndrea Arcangeli if (isolate_lru_page(page)) { 1691ba76149fSAndrea Arcangeli unlock_page(page); 1692ba76149fSAndrea Arcangeli release_pte_pages(pte, _pte); 1693ba76149fSAndrea Arcangeli goto out; 1694ba76149fSAndrea Arcangeli } 1695ba76149fSAndrea Arcangeli /* 0 stands for page_is_file_cache(page) == false */ 1696ba76149fSAndrea Arcangeli inc_zone_page_state(page, NR_ISOLATED_ANON + 0); 1697ba76149fSAndrea Arcangeli VM_BUG_ON(!PageLocked(page)); 1698ba76149fSAndrea Arcangeli VM_BUG_ON(PageLRU(page)); 1699ba76149fSAndrea Arcangeli 1700ba76149fSAndrea Arcangeli /* If there is no mapped pte young don't collapse the page */ 17018ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 17028ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 1703ba76149fSAndrea Arcangeli referenced = 1; 1704ba76149fSAndrea Arcangeli } 1705ba76149fSAndrea Arcangeli if (unlikely(!referenced)) 1706ba76149fSAndrea Arcangeli release_all_pte_pages(pte); 1707ba76149fSAndrea Arcangeli else 1708ba76149fSAndrea Arcangeli isolated = 1; 1709ba76149fSAndrea Arcangeli out: 1710ba76149fSAndrea Arcangeli return isolated; 1711ba76149fSAndrea Arcangeli } 1712ba76149fSAndrea Arcangeli 1713ba76149fSAndrea Arcangeli static void __collapse_huge_page_copy(pte_t *pte, struct page *page, 1714ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 1715ba76149fSAndrea Arcangeli unsigned long address, 1716ba76149fSAndrea Arcangeli spinlock_t *ptl) 1717ba76149fSAndrea Arcangeli { 1718ba76149fSAndrea Arcangeli pte_t *_pte; 1719ba76149fSAndrea Arcangeli for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { 1720ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 1721ba76149fSAndrea Arcangeli struct page *src_page; 1722ba76149fSAndrea Arcangeli 1723ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 1724ba76149fSAndrea Arcangeli clear_user_highpage(page, address); 1725ba76149fSAndrea Arcangeli add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); 1726ba76149fSAndrea Arcangeli } else { 1727ba76149fSAndrea Arcangeli src_page = pte_page(pteval); 1728ba76149fSAndrea Arcangeli copy_user_highpage(page, src_page, address, vma); 1729ba76149fSAndrea Arcangeli VM_BUG_ON(page_mapcount(src_page) != 1); 1730ba76149fSAndrea Arcangeli VM_BUG_ON(page_count(src_page) != 2); 1731ba76149fSAndrea Arcangeli release_pte_page(src_page); 1732ba76149fSAndrea Arcangeli /* 1733ba76149fSAndrea Arcangeli * ptl mostly unnecessary, but preempt has to 1734ba76149fSAndrea Arcangeli * be disabled to update the per-cpu stats 1735ba76149fSAndrea Arcangeli * inside page_remove_rmap(). 1736ba76149fSAndrea Arcangeli */ 1737ba76149fSAndrea Arcangeli spin_lock(ptl); 1738ba76149fSAndrea Arcangeli /* 1739ba76149fSAndrea Arcangeli * paravirt calls inside pte_clear here are 1740ba76149fSAndrea Arcangeli * superfluous. 1741ba76149fSAndrea Arcangeli */ 1742ba76149fSAndrea Arcangeli pte_clear(vma->vm_mm, address, _pte); 1743ba76149fSAndrea Arcangeli page_remove_rmap(src_page); 1744ba76149fSAndrea Arcangeli spin_unlock(ptl); 1745ba76149fSAndrea Arcangeli free_page_and_swap_cache(src_page); 1746ba76149fSAndrea Arcangeli } 1747ba76149fSAndrea Arcangeli 1748ba76149fSAndrea Arcangeli address += PAGE_SIZE; 1749ba76149fSAndrea Arcangeli page++; 1750ba76149fSAndrea Arcangeli } 1751ba76149fSAndrea Arcangeli } 1752ba76149fSAndrea Arcangeli 1753ba76149fSAndrea Arcangeli static void collapse_huge_page(struct mm_struct *mm, 1754ba76149fSAndrea Arcangeli unsigned long address, 1755ce83d217SAndrea Arcangeli struct page **hpage, 17565c4b4be3SAndi Kleen struct vm_area_struct *vma, 17575c4b4be3SAndi Kleen int node) 1758ba76149fSAndrea Arcangeli { 1759ba76149fSAndrea Arcangeli pgd_t *pgd; 1760ba76149fSAndrea Arcangeli pud_t *pud; 1761ba76149fSAndrea Arcangeli pmd_t *pmd, _pmd; 1762ba76149fSAndrea Arcangeli pte_t *pte; 1763ba76149fSAndrea Arcangeli pgtable_t pgtable; 1764ba76149fSAndrea Arcangeli struct page *new_page; 1765ba76149fSAndrea Arcangeli spinlock_t *ptl; 1766ba76149fSAndrea Arcangeli int isolated; 1767ba76149fSAndrea Arcangeli unsigned long hstart, hend; 1768ba76149fSAndrea Arcangeli 1769ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 17700bbbc0b3SAndrea Arcangeli #ifndef CONFIG_NUMA 1771ba76149fSAndrea Arcangeli VM_BUG_ON(!*hpage); 1772ce83d217SAndrea Arcangeli new_page = *hpage; 17732fbfac4eSHugh Dickins if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { 17742fbfac4eSHugh Dickins up_read(&mm->mmap_sem); 17752fbfac4eSHugh Dickins return; 17762fbfac4eSHugh Dickins } 17770bbbc0b3SAndrea Arcangeli #else 17780bbbc0b3SAndrea Arcangeli VM_BUG_ON(*hpage); 1779ce83d217SAndrea Arcangeli /* 1780ce83d217SAndrea Arcangeli * Allocate the page while the vma is still valid and under 1781ce83d217SAndrea Arcangeli * the mmap_sem read mode so there is no memory allocation 1782ce83d217SAndrea Arcangeli * later when we take the mmap_sem in write mode. This is more 1783ce83d217SAndrea Arcangeli * friendly behavior (OTOH it may actually hide bugs) to 1784ce83d217SAndrea Arcangeli * filesystems in userland with daemons allocating memory in 1785ce83d217SAndrea Arcangeli * the userland I/O paths. Allocating memory with the 1786ce83d217SAndrea Arcangeli * mmap_sem in read mode is good idea also to allow greater 1787ce83d217SAndrea Arcangeli * scalability. 1788ce83d217SAndrea Arcangeli */ 17895c4b4be3SAndi Kleen new_page = alloc_hugepage_vma(khugepaged_defrag(), vma, address, 1790cc5d462fSAndi Kleen node, __GFP_OTHER_NODE); 1791ce83d217SAndrea Arcangeli if (unlikely(!new_page)) { 1792ce83d217SAndrea Arcangeli up_read(&mm->mmap_sem); 1793*81ab4201SAndi Kleen count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 1794ce83d217SAndrea Arcangeli *hpage = ERR_PTR(-ENOMEM); 1795ce83d217SAndrea Arcangeli return; 1796ce83d217SAndrea Arcangeli } 1797*81ab4201SAndi Kleen count_vm_event(THP_COLLAPSE_ALLOC); 1798ce83d217SAndrea Arcangeli if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { 1799ce83d217SAndrea Arcangeli up_read(&mm->mmap_sem); 1800ce83d217SAndrea Arcangeli put_page(new_page); 1801ce83d217SAndrea Arcangeli return; 1802ce83d217SAndrea Arcangeli } 18032fbfac4eSHugh Dickins #endif 1804ce83d217SAndrea Arcangeli 1805ce83d217SAndrea Arcangeli /* after allocating the hugepage upgrade to mmap_sem write mode */ 1806ce83d217SAndrea Arcangeli up_read(&mm->mmap_sem); 1807ba76149fSAndrea Arcangeli 1808ba76149fSAndrea Arcangeli /* 1809ba76149fSAndrea Arcangeli * Prevent all access to pagetables with the exception of 1810ba76149fSAndrea Arcangeli * gup_fast later hanlded by the ptep_clear_flush and the VM 1811ba76149fSAndrea Arcangeli * handled by the anon_vma lock + PG_lock. 1812ba76149fSAndrea Arcangeli */ 1813ba76149fSAndrea Arcangeli down_write(&mm->mmap_sem); 1814ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 1815ba76149fSAndrea Arcangeli goto out; 1816ba76149fSAndrea Arcangeli 1817ba76149fSAndrea Arcangeli vma = find_vma(mm, address); 1818ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 1819ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 1820ba76149fSAndrea Arcangeli if (address < hstart || address + HPAGE_PMD_SIZE > hend) 1821ba76149fSAndrea Arcangeli goto out; 1822ba76149fSAndrea Arcangeli 182360ab3244SAndrea Arcangeli if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || 182460ab3244SAndrea Arcangeli (vma->vm_flags & VM_NOHUGEPAGE)) 1825ba76149fSAndrea Arcangeli goto out; 1826ba76149fSAndrea Arcangeli 1827ba76149fSAndrea Arcangeli /* VM_PFNMAP vmas may have vm_ops null but vm_file set */ 1828ba76149fSAndrea Arcangeli if (!vma->anon_vma || vma->vm_ops || vma->vm_file) 1829ba76149fSAndrea Arcangeli goto out; 1830a7d6e4ecSAndrea Arcangeli if (is_vma_temporary_stack(vma)) 1831a7d6e4ecSAndrea Arcangeli goto out; 1832ba76149fSAndrea Arcangeli VM_BUG_ON(is_linear_pfn_mapping(vma) || is_pfn_mapping(vma)); 1833ba76149fSAndrea Arcangeli 1834ba76149fSAndrea Arcangeli pgd = pgd_offset(mm, address); 1835ba76149fSAndrea Arcangeli if (!pgd_present(*pgd)) 1836ba76149fSAndrea Arcangeli goto out; 1837ba76149fSAndrea Arcangeli 1838ba76149fSAndrea Arcangeli pud = pud_offset(pgd, address); 1839ba76149fSAndrea Arcangeli if (!pud_present(*pud)) 1840ba76149fSAndrea Arcangeli goto out; 1841ba76149fSAndrea Arcangeli 1842ba76149fSAndrea Arcangeli pmd = pmd_offset(pud, address); 1843ba76149fSAndrea Arcangeli /* pmd can't go away or become huge under us */ 1844ba76149fSAndrea Arcangeli if (!pmd_present(*pmd) || pmd_trans_huge(*pmd)) 1845ba76149fSAndrea Arcangeli goto out; 1846ba76149fSAndrea Arcangeli 1847ba76149fSAndrea Arcangeli anon_vma_lock(vma->anon_vma); 1848ba76149fSAndrea Arcangeli 1849ba76149fSAndrea Arcangeli pte = pte_offset_map(pmd, address); 1850ba76149fSAndrea Arcangeli ptl = pte_lockptr(mm, pmd); 1851ba76149fSAndrea Arcangeli 1852ba76149fSAndrea Arcangeli spin_lock(&mm->page_table_lock); /* probably unnecessary */ 1853ba76149fSAndrea Arcangeli /* 1854ba76149fSAndrea Arcangeli * After this gup_fast can't run anymore. This also removes 1855ba76149fSAndrea Arcangeli * any huge TLB entry from the CPU so we won't allow 1856ba76149fSAndrea Arcangeli * huge and small TLB entries for the same virtual address 1857ba76149fSAndrea Arcangeli * to avoid the risk of CPU bugs in that area. 1858ba76149fSAndrea Arcangeli */ 1859ba76149fSAndrea Arcangeli _pmd = pmdp_clear_flush_notify(vma, address, pmd); 1860ba76149fSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 1861ba76149fSAndrea Arcangeli 1862ba76149fSAndrea Arcangeli spin_lock(ptl); 1863ba76149fSAndrea Arcangeli isolated = __collapse_huge_page_isolate(vma, address, pte); 1864ba76149fSAndrea Arcangeli spin_unlock(ptl); 1865ba76149fSAndrea Arcangeli 1866ba76149fSAndrea Arcangeli if (unlikely(!isolated)) { 1867453c7192SJohannes Weiner pte_unmap(pte); 1868ba76149fSAndrea Arcangeli spin_lock(&mm->page_table_lock); 1869ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 1870ba76149fSAndrea Arcangeli set_pmd_at(mm, address, pmd, _pmd); 1871ba76149fSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 1872ba76149fSAndrea Arcangeli anon_vma_unlock(vma->anon_vma); 1873ce83d217SAndrea Arcangeli goto out; 1874ba76149fSAndrea Arcangeli } 1875ba76149fSAndrea Arcangeli 1876ba76149fSAndrea Arcangeli /* 1877ba76149fSAndrea Arcangeli * All pages are isolated and locked so anon_vma rmap 1878ba76149fSAndrea Arcangeli * can't run anymore. 1879ba76149fSAndrea Arcangeli */ 1880ba76149fSAndrea Arcangeli anon_vma_unlock(vma->anon_vma); 1881ba76149fSAndrea Arcangeli 1882ba76149fSAndrea Arcangeli __collapse_huge_page_copy(pte, new_page, vma, address, ptl); 1883453c7192SJohannes Weiner pte_unmap(pte); 1884ba76149fSAndrea Arcangeli __SetPageUptodate(new_page); 1885ba76149fSAndrea Arcangeli pgtable = pmd_pgtable(_pmd); 1886ba76149fSAndrea Arcangeli VM_BUG_ON(page_count(pgtable) != 1); 1887ba76149fSAndrea Arcangeli VM_BUG_ON(page_mapcount(pgtable) != 0); 1888ba76149fSAndrea Arcangeli 1889ba76149fSAndrea Arcangeli _pmd = mk_pmd(new_page, vma->vm_page_prot); 1890ba76149fSAndrea Arcangeli _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); 1891ba76149fSAndrea Arcangeli _pmd = pmd_mkhuge(_pmd); 1892ba76149fSAndrea Arcangeli 1893ba76149fSAndrea Arcangeli /* 1894ba76149fSAndrea Arcangeli * spin_lock() below is not the equivalent of smp_wmb(), so 1895ba76149fSAndrea Arcangeli * this is needed to avoid the copy_huge_page writes to become 1896ba76149fSAndrea Arcangeli * visible after the set_pmd_at() write. 1897ba76149fSAndrea Arcangeli */ 1898ba76149fSAndrea Arcangeli smp_wmb(); 1899ba76149fSAndrea Arcangeli 1900ba76149fSAndrea Arcangeli spin_lock(&mm->page_table_lock); 1901ba76149fSAndrea Arcangeli BUG_ON(!pmd_none(*pmd)); 1902ba76149fSAndrea Arcangeli page_add_new_anon_rmap(new_page, vma, address); 1903ba76149fSAndrea Arcangeli set_pmd_at(mm, address, pmd, _pmd); 1904ba76149fSAndrea Arcangeli update_mmu_cache(vma, address, entry); 1905ba76149fSAndrea Arcangeli prepare_pmd_huge_pte(pgtable, mm); 1906ba76149fSAndrea Arcangeli mm->nr_ptes--; 1907ba76149fSAndrea Arcangeli spin_unlock(&mm->page_table_lock); 1908ba76149fSAndrea Arcangeli 19090bbbc0b3SAndrea Arcangeli #ifndef CONFIG_NUMA 1910ba76149fSAndrea Arcangeli *hpage = NULL; 19110bbbc0b3SAndrea Arcangeli #endif 1912ba76149fSAndrea Arcangeli khugepaged_pages_collapsed++; 1913ce83d217SAndrea Arcangeli out_up_write: 1914ba76149fSAndrea Arcangeli up_write(&mm->mmap_sem); 19150bbbc0b3SAndrea Arcangeli return; 19160bbbc0b3SAndrea Arcangeli 1917ce83d217SAndrea Arcangeli out: 1918678ff896SKAMEZAWA Hiroyuki mem_cgroup_uncharge_page(new_page); 19190bbbc0b3SAndrea Arcangeli #ifdef CONFIG_NUMA 19200bbbc0b3SAndrea Arcangeli put_page(new_page); 19210bbbc0b3SAndrea Arcangeli #endif 1922ce83d217SAndrea Arcangeli goto out_up_write; 1923ba76149fSAndrea Arcangeli } 1924ba76149fSAndrea Arcangeli 1925ba76149fSAndrea Arcangeli static int khugepaged_scan_pmd(struct mm_struct *mm, 1926ba76149fSAndrea Arcangeli struct vm_area_struct *vma, 1927ba76149fSAndrea Arcangeli unsigned long address, 1928ba76149fSAndrea Arcangeli struct page **hpage) 1929ba76149fSAndrea Arcangeli { 1930ba76149fSAndrea Arcangeli pgd_t *pgd; 1931ba76149fSAndrea Arcangeli pud_t *pud; 1932ba76149fSAndrea Arcangeli pmd_t *pmd; 1933ba76149fSAndrea Arcangeli pte_t *pte, *_pte; 1934ba76149fSAndrea Arcangeli int ret = 0, referenced = 0, none = 0; 1935ba76149fSAndrea Arcangeli struct page *page; 1936ba76149fSAndrea Arcangeli unsigned long _address; 1937ba76149fSAndrea Arcangeli spinlock_t *ptl; 19385c4b4be3SAndi Kleen int node = -1; 1939ba76149fSAndrea Arcangeli 1940ba76149fSAndrea Arcangeli VM_BUG_ON(address & ~HPAGE_PMD_MASK); 1941ba76149fSAndrea Arcangeli 1942ba76149fSAndrea Arcangeli pgd = pgd_offset(mm, address); 1943ba76149fSAndrea Arcangeli if (!pgd_present(*pgd)) 1944ba76149fSAndrea Arcangeli goto out; 1945ba76149fSAndrea Arcangeli 1946ba76149fSAndrea Arcangeli pud = pud_offset(pgd, address); 1947ba76149fSAndrea Arcangeli if (!pud_present(*pud)) 1948ba76149fSAndrea Arcangeli goto out; 1949ba76149fSAndrea Arcangeli 1950ba76149fSAndrea Arcangeli pmd = pmd_offset(pud, address); 1951ba76149fSAndrea Arcangeli if (!pmd_present(*pmd) || pmd_trans_huge(*pmd)) 1952ba76149fSAndrea Arcangeli goto out; 1953ba76149fSAndrea Arcangeli 1954ba76149fSAndrea Arcangeli pte = pte_offset_map_lock(mm, pmd, address, &ptl); 1955ba76149fSAndrea Arcangeli for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; 1956ba76149fSAndrea Arcangeli _pte++, _address += PAGE_SIZE) { 1957ba76149fSAndrea Arcangeli pte_t pteval = *_pte; 1958ba76149fSAndrea Arcangeli if (pte_none(pteval)) { 1959ba76149fSAndrea Arcangeli if (++none <= khugepaged_max_ptes_none) 1960ba76149fSAndrea Arcangeli continue; 1961ba76149fSAndrea Arcangeli else 1962ba76149fSAndrea Arcangeli goto out_unmap; 1963ba76149fSAndrea Arcangeli } 1964ba76149fSAndrea Arcangeli if (!pte_present(pteval) || !pte_write(pteval)) 1965ba76149fSAndrea Arcangeli goto out_unmap; 1966ba76149fSAndrea Arcangeli page = vm_normal_page(vma, _address, pteval); 1967ba76149fSAndrea Arcangeli if (unlikely(!page)) 1968ba76149fSAndrea Arcangeli goto out_unmap; 19695c4b4be3SAndi Kleen /* 19705c4b4be3SAndi Kleen * Chose the node of the first page. This could 19715c4b4be3SAndi Kleen * be more sophisticated and look at more pages, 19725c4b4be3SAndi Kleen * but isn't for now. 19735c4b4be3SAndi Kleen */ 19745c4b4be3SAndi Kleen if (node == -1) 19755c4b4be3SAndi Kleen node = page_to_nid(page); 1976ba76149fSAndrea Arcangeli VM_BUG_ON(PageCompound(page)); 1977ba76149fSAndrea Arcangeli if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) 1978ba76149fSAndrea Arcangeli goto out_unmap; 1979ba76149fSAndrea Arcangeli /* cannot use mapcount: can't collapse if there's a gup pin */ 1980ba76149fSAndrea Arcangeli if (page_count(page) != 1) 1981ba76149fSAndrea Arcangeli goto out_unmap; 19828ee53820SAndrea Arcangeli if (pte_young(pteval) || PageReferenced(page) || 19838ee53820SAndrea Arcangeli mmu_notifier_test_young(vma->vm_mm, address)) 1984ba76149fSAndrea Arcangeli referenced = 1; 1985ba76149fSAndrea Arcangeli } 1986ba76149fSAndrea Arcangeli if (referenced) 1987ba76149fSAndrea Arcangeli ret = 1; 1988ba76149fSAndrea Arcangeli out_unmap: 1989ba76149fSAndrea Arcangeli pte_unmap_unlock(pte, ptl); 1990ce83d217SAndrea Arcangeli if (ret) 1991ce83d217SAndrea Arcangeli /* collapse_huge_page will return with the mmap_sem released */ 19925c4b4be3SAndi Kleen collapse_huge_page(mm, address, hpage, vma, node); 1993ba76149fSAndrea Arcangeli out: 1994ba76149fSAndrea Arcangeli return ret; 1995ba76149fSAndrea Arcangeli } 1996ba76149fSAndrea Arcangeli 1997ba76149fSAndrea Arcangeli static void collect_mm_slot(struct mm_slot *mm_slot) 1998ba76149fSAndrea Arcangeli { 1999ba76149fSAndrea Arcangeli struct mm_struct *mm = mm_slot->mm; 2000ba76149fSAndrea Arcangeli 2001ba76149fSAndrea Arcangeli VM_BUG_ON(!spin_is_locked(&khugepaged_mm_lock)); 2002ba76149fSAndrea Arcangeli 2003ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm)) { 2004ba76149fSAndrea Arcangeli /* free mm_slot */ 2005ba76149fSAndrea Arcangeli hlist_del(&mm_slot->hash); 2006ba76149fSAndrea Arcangeli list_del(&mm_slot->mm_node); 2007ba76149fSAndrea Arcangeli 2008ba76149fSAndrea Arcangeli /* 2009ba76149fSAndrea Arcangeli * Not strictly needed because the mm exited already. 2010ba76149fSAndrea Arcangeli * 2011ba76149fSAndrea Arcangeli * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); 2012ba76149fSAndrea Arcangeli */ 2013ba76149fSAndrea Arcangeli 2014ba76149fSAndrea Arcangeli /* khugepaged_mm_lock actually not necessary for the below */ 2015ba76149fSAndrea Arcangeli free_mm_slot(mm_slot); 2016ba76149fSAndrea Arcangeli mmdrop(mm); 2017ba76149fSAndrea Arcangeli } 2018ba76149fSAndrea Arcangeli } 2019ba76149fSAndrea Arcangeli 2020ba76149fSAndrea Arcangeli static unsigned int khugepaged_scan_mm_slot(unsigned int pages, 2021ba76149fSAndrea Arcangeli struct page **hpage) 2022ba76149fSAndrea Arcangeli { 2023ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2024ba76149fSAndrea Arcangeli struct mm_struct *mm; 2025ba76149fSAndrea Arcangeli struct vm_area_struct *vma; 2026ba76149fSAndrea Arcangeli int progress = 0; 2027ba76149fSAndrea Arcangeli 2028ba76149fSAndrea Arcangeli VM_BUG_ON(!pages); 2029ba76149fSAndrea Arcangeli VM_BUG_ON(!spin_is_locked(&khugepaged_mm_lock)); 2030ba76149fSAndrea Arcangeli 2031ba76149fSAndrea Arcangeli if (khugepaged_scan.mm_slot) 2032ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2033ba76149fSAndrea Arcangeli else { 2034ba76149fSAndrea Arcangeli mm_slot = list_entry(khugepaged_scan.mm_head.next, 2035ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2036ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2037ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = mm_slot; 2038ba76149fSAndrea Arcangeli } 2039ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2040ba76149fSAndrea Arcangeli 2041ba76149fSAndrea Arcangeli mm = mm_slot->mm; 2042ba76149fSAndrea Arcangeli down_read(&mm->mmap_sem); 2043ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2044ba76149fSAndrea Arcangeli vma = NULL; 2045ba76149fSAndrea Arcangeli else 2046ba76149fSAndrea Arcangeli vma = find_vma(mm, khugepaged_scan.address); 2047ba76149fSAndrea Arcangeli 2048ba76149fSAndrea Arcangeli progress++; 2049ba76149fSAndrea Arcangeli for (; vma; vma = vma->vm_next) { 2050ba76149fSAndrea Arcangeli unsigned long hstart, hend; 2051ba76149fSAndrea Arcangeli 2052ba76149fSAndrea Arcangeli cond_resched(); 2053ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) { 2054ba76149fSAndrea Arcangeli progress++; 2055ba76149fSAndrea Arcangeli break; 2056ba76149fSAndrea Arcangeli } 2057ba76149fSAndrea Arcangeli 205860ab3244SAndrea Arcangeli if ((!(vma->vm_flags & VM_HUGEPAGE) && 205960ab3244SAndrea Arcangeli !khugepaged_always()) || 206060ab3244SAndrea Arcangeli (vma->vm_flags & VM_NOHUGEPAGE)) { 2061a7d6e4ecSAndrea Arcangeli skip: 2062ba76149fSAndrea Arcangeli progress++; 2063ba76149fSAndrea Arcangeli continue; 2064ba76149fSAndrea Arcangeli } 2065ba76149fSAndrea Arcangeli /* VM_PFNMAP vmas may have vm_ops null but vm_file set */ 2066a7d6e4ecSAndrea Arcangeli if (!vma->anon_vma || vma->vm_ops || vma->vm_file) 2067a7d6e4ecSAndrea Arcangeli goto skip; 2068a7d6e4ecSAndrea Arcangeli if (is_vma_temporary_stack(vma)) 2069a7d6e4ecSAndrea Arcangeli goto skip; 2070a7d6e4ecSAndrea Arcangeli 2071ba76149fSAndrea Arcangeli VM_BUG_ON(is_linear_pfn_mapping(vma) || is_pfn_mapping(vma)); 2072ba76149fSAndrea Arcangeli 2073ba76149fSAndrea Arcangeli hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 2074ba76149fSAndrea Arcangeli hend = vma->vm_end & HPAGE_PMD_MASK; 2075a7d6e4ecSAndrea Arcangeli if (hstart >= hend) 2076a7d6e4ecSAndrea Arcangeli goto skip; 2077a7d6e4ecSAndrea Arcangeli if (khugepaged_scan.address > hend) 2078a7d6e4ecSAndrea Arcangeli goto skip; 2079ba76149fSAndrea Arcangeli if (khugepaged_scan.address < hstart) 2080ba76149fSAndrea Arcangeli khugepaged_scan.address = hstart; 2081a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); 2082ba76149fSAndrea Arcangeli 2083ba76149fSAndrea Arcangeli while (khugepaged_scan.address < hend) { 2084ba76149fSAndrea Arcangeli int ret; 2085ba76149fSAndrea Arcangeli cond_resched(); 2086ba76149fSAndrea Arcangeli if (unlikely(khugepaged_test_exit(mm))) 2087ba76149fSAndrea Arcangeli goto breakouterloop; 2088ba76149fSAndrea Arcangeli 2089ba76149fSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.address < hstart || 2090ba76149fSAndrea Arcangeli khugepaged_scan.address + HPAGE_PMD_SIZE > 2091ba76149fSAndrea Arcangeli hend); 2092ba76149fSAndrea Arcangeli ret = khugepaged_scan_pmd(mm, vma, 2093ba76149fSAndrea Arcangeli khugepaged_scan.address, 2094ba76149fSAndrea Arcangeli hpage); 2095ba76149fSAndrea Arcangeli /* move to next address */ 2096ba76149fSAndrea Arcangeli khugepaged_scan.address += HPAGE_PMD_SIZE; 2097ba76149fSAndrea Arcangeli progress += HPAGE_PMD_NR; 2098ba76149fSAndrea Arcangeli if (ret) 2099ba76149fSAndrea Arcangeli /* we released mmap_sem so break loop */ 2100ba76149fSAndrea Arcangeli goto breakouterloop_mmap_sem; 2101ba76149fSAndrea Arcangeli if (progress >= pages) 2102ba76149fSAndrea Arcangeli goto breakouterloop; 2103ba76149fSAndrea Arcangeli } 2104ba76149fSAndrea Arcangeli } 2105ba76149fSAndrea Arcangeli breakouterloop: 2106ba76149fSAndrea Arcangeli up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ 2107ba76149fSAndrea Arcangeli breakouterloop_mmap_sem: 2108ba76149fSAndrea Arcangeli 2109ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2110a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); 2111ba76149fSAndrea Arcangeli /* 2112ba76149fSAndrea Arcangeli * Release the current mm_slot if this mm is about to die, or 2113ba76149fSAndrea Arcangeli * if we scanned all vmas of this mm. 2114ba76149fSAndrea Arcangeli */ 2115ba76149fSAndrea Arcangeli if (khugepaged_test_exit(mm) || !vma) { 2116ba76149fSAndrea Arcangeli /* 2117ba76149fSAndrea Arcangeli * Make sure that if mm_users is reaching zero while 2118ba76149fSAndrea Arcangeli * khugepaged runs here, khugepaged_exit will find 2119ba76149fSAndrea Arcangeli * mm_slot not pointing to the exiting mm. 2120ba76149fSAndrea Arcangeli */ 2121ba76149fSAndrea Arcangeli if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { 2122ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = list_entry( 2123ba76149fSAndrea Arcangeli mm_slot->mm_node.next, 2124ba76149fSAndrea Arcangeli struct mm_slot, mm_node); 2125ba76149fSAndrea Arcangeli khugepaged_scan.address = 0; 2126ba76149fSAndrea Arcangeli } else { 2127ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2128ba76149fSAndrea Arcangeli khugepaged_full_scans++; 2129ba76149fSAndrea Arcangeli } 2130ba76149fSAndrea Arcangeli 2131ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2132ba76149fSAndrea Arcangeli } 2133ba76149fSAndrea Arcangeli 2134ba76149fSAndrea Arcangeli return progress; 2135ba76149fSAndrea Arcangeli } 2136ba76149fSAndrea Arcangeli 2137ba76149fSAndrea Arcangeli static int khugepaged_has_work(void) 2138ba76149fSAndrea Arcangeli { 2139ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) && 2140ba76149fSAndrea Arcangeli khugepaged_enabled(); 2141ba76149fSAndrea Arcangeli } 2142ba76149fSAndrea Arcangeli 2143ba76149fSAndrea Arcangeli static int khugepaged_wait_event(void) 2144ba76149fSAndrea Arcangeli { 2145ba76149fSAndrea Arcangeli return !list_empty(&khugepaged_scan.mm_head) || 2146ba76149fSAndrea Arcangeli !khugepaged_enabled(); 2147ba76149fSAndrea Arcangeli } 2148ba76149fSAndrea Arcangeli 2149ba76149fSAndrea Arcangeli static void khugepaged_do_scan(struct page **hpage) 2150ba76149fSAndrea Arcangeli { 2151ba76149fSAndrea Arcangeli unsigned int progress = 0, pass_through_head = 0; 2152ba76149fSAndrea Arcangeli unsigned int pages = khugepaged_pages_to_scan; 2153ba76149fSAndrea Arcangeli 2154ba76149fSAndrea Arcangeli barrier(); /* write khugepaged_pages_to_scan to local stack */ 2155ba76149fSAndrea Arcangeli 2156ba76149fSAndrea Arcangeli while (progress < pages) { 2157ba76149fSAndrea Arcangeli cond_resched(); 2158ba76149fSAndrea Arcangeli 21590bbbc0b3SAndrea Arcangeli #ifndef CONFIG_NUMA 2160ba76149fSAndrea Arcangeli if (!*hpage) { 2161ba76149fSAndrea Arcangeli *hpage = alloc_hugepage(khugepaged_defrag()); 2162*81ab4201SAndi Kleen if (unlikely(!*hpage)) { 2163*81ab4201SAndi Kleen count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 2164ba76149fSAndrea Arcangeli break; 2165ba76149fSAndrea Arcangeli } 2166*81ab4201SAndi Kleen count_vm_event(THP_COLLAPSE_ALLOC); 2167*81ab4201SAndi Kleen } 21680bbbc0b3SAndrea Arcangeli #else 21690bbbc0b3SAndrea Arcangeli if (IS_ERR(*hpage)) 21700bbbc0b3SAndrea Arcangeli break; 21710bbbc0b3SAndrea Arcangeli #endif 2172ba76149fSAndrea Arcangeli 2173878aee7dSAndrea Arcangeli if (unlikely(kthread_should_stop() || freezing(current))) 2174878aee7dSAndrea Arcangeli break; 2175878aee7dSAndrea Arcangeli 2176ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2177ba76149fSAndrea Arcangeli if (!khugepaged_scan.mm_slot) 2178ba76149fSAndrea Arcangeli pass_through_head++; 2179ba76149fSAndrea Arcangeli if (khugepaged_has_work() && 2180ba76149fSAndrea Arcangeli pass_through_head < 2) 2181ba76149fSAndrea Arcangeli progress += khugepaged_scan_mm_slot(pages - progress, 2182ba76149fSAndrea Arcangeli hpage); 2183ba76149fSAndrea Arcangeli else 2184ba76149fSAndrea Arcangeli progress = pages; 2185ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2186ba76149fSAndrea Arcangeli } 2187ba76149fSAndrea Arcangeli } 2188ba76149fSAndrea Arcangeli 21890bbbc0b3SAndrea Arcangeli static void khugepaged_alloc_sleep(void) 2190ba76149fSAndrea Arcangeli { 2191ba76149fSAndrea Arcangeli DEFINE_WAIT(wait); 2192ba76149fSAndrea Arcangeli add_wait_queue(&khugepaged_wait, &wait); 2193ba76149fSAndrea Arcangeli schedule_timeout_interruptible( 2194ba76149fSAndrea Arcangeli msecs_to_jiffies( 2195ba76149fSAndrea Arcangeli khugepaged_alloc_sleep_millisecs)); 2196ba76149fSAndrea Arcangeli remove_wait_queue(&khugepaged_wait, &wait); 2197ba76149fSAndrea Arcangeli } 21980bbbc0b3SAndrea Arcangeli 21990bbbc0b3SAndrea Arcangeli #ifndef CONFIG_NUMA 22000bbbc0b3SAndrea Arcangeli static struct page *khugepaged_alloc_hugepage(void) 22010bbbc0b3SAndrea Arcangeli { 22020bbbc0b3SAndrea Arcangeli struct page *hpage; 22030bbbc0b3SAndrea Arcangeli 22040bbbc0b3SAndrea Arcangeli do { 22050bbbc0b3SAndrea Arcangeli hpage = alloc_hugepage(khugepaged_defrag()); 2206*81ab4201SAndi Kleen if (!hpage) { 2207*81ab4201SAndi Kleen count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 22080bbbc0b3SAndrea Arcangeli khugepaged_alloc_sleep(); 2209*81ab4201SAndi Kleen } else 2210*81ab4201SAndi Kleen count_vm_event(THP_COLLAPSE_ALLOC); 2211ba76149fSAndrea Arcangeli } while (unlikely(!hpage) && 2212ba76149fSAndrea Arcangeli likely(khugepaged_enabled())); 2213ba76149fSAndrea Arcangeli return hpage; 2214ba76149fSAndrea Arcangeli } 22150bbbc0b3SAndrea Arcangeli #endif 2216ba76149fSAndrea Arcangeli 2217ba76149fSAndrea Arcangeli static void khugepaged_loop(void) 2218ba76149fSAndrea Arcangeli { 2219ba76149fSAndrea Arcangeli struct page *hpage; 2220ba76149fSAndrea Arcangeli 22210bbbc0b3SAndrea Arcangeli #ifdef CONFIG_NUMA 22220bbbc0b3SAndrea Arcangeli hpage = NULL; 22230bbbc0b3SAndrea Arcangeli #endif 2224ba76149fSAndrea Arcangeli while (likely(khugepaged_enabled())) { 22250bbbc0b3SAndrea Arcangeli #ifndef CONFIG_NUMA 2226ba76149fSAndrea Arcangeli hpage = khugepaged_alloc_hugepage(); 2227*81ab4201SAndi Kleen if (unlikely(!hpage)) { 2228*81ab4201SAndi Kleen count_vm_event(THP_COLLAPSE_ALLOC_FAILED); 2229ba76149fSAndrea Arcangeli break; 2230*81ab4201SAndi Kleen } 2231*81ab4201SAndi Kleen count_vm_event(THP_COLLAPSE_ALLOC); 22320bbbc0b3SAndrea Arcangeli #else 22330bbbc0b3SAndrea Arcangeli if (IS_ERR(hpage)) { 22340bbbc0b3SAndrea Arcangeli khugepaged_alloc_sleep(); 22350bbbc0b3SAndrea Arcangeli hpage = NULL; 22360bbbc0b3SAndrea Arcangeli } 22370bbbc0b3SAndrea Arcangeli #endif 2238ba76149fSAndrea Arcangeli 2239ba76149fSAndrea Arcangeli khugepaged_do_scan(&hpage); 22400bbbc0b3SAndrea Arcangeli #ifndef CONFIG_NUMA 2241ba76149fSAndrea Arcangeli if (hpage) 2242ba76149fSAndrea Arcangeli put_page(hpage); 22430bbbc0b3SAndrea Arcangeli #endif 2244878aee7dSAndrea Arcangeli try_to_freeze(); 2245878aee7dSAndrea Arcangeli if (unlikely(kthread_should_stop())) 2246878aee7dSAndrea Arcangeli break; 2247ba76149fSAndrea Arcangeli if (khugepaged_has_work()) { 2248ba76149fSAndrea Arcangeli DEFINE_WAIT(wait); 2249ba76149fSAndrea Arcangeli if (!khugepaged_scan_sleep_millisecs) 2250ba76149fSAndrea Arcangeli continue; 2251ba76149fSAndrea Arcangeli add_wait_queue(&khugepaged_wait, &wait); 2252ba76149fSAndrea Arcangeli schedule_timeout_interruptible( 2253ba76149fSAndrea Arcangeli msecs_to_jiffies( 2254ba76149fSAndrea Arcangeli khugepaged_scan_sleep_millisecs)); 2255ba76149fSAndrea Arcangeli remove_wait_queue(&khugepaged_wait, &wait); 2256ba76149fSAndrea Arcangeli } else if (khugepaged_enabled()) 2257878aee7dSAndrea Arcangeli wait_event_freezable(khugepaged_wait, 2258ba76149fSAndrea Arcangeli khugepaged_wait_event()); 2259ba76149fSAndrea Arcangeli } 2260ba76149fSAndrea Arcangeli } 2261ba76149fSAndrea Arcangeli 2262ba76149fSAndrea Arcangeli static int khugepaged(void *none) 2263ba76149fSAndrea Arcangeli { 2264ba76149fSAndrea Arcangeli struct mm_slot *mm_slot; 2265ba76149fSAndrea Arcangeli 2266878aee7dSAndrea Arcangeli set_freezable(); 2267ba76149fSAndrea Arcangeli set_user_nice(current, 19); 2268ba76149fSAndrea Arcangeli 2269ba76149fSAndrea Arcangeli /* serialize with start_khugepaged() */ 2270ba76149fSAndrea Arcangeli mutex_lock(&khugepaged_mutex); 2271ba76149fSAndrea Arcangeli 2272ba76149fSAndrea Arcangeli for (;;) { 2273ba76149fSAndrea Arcangeli mutex_unlock(&khugepaged_mutex); 2274a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_thread != current); 2275ba76149fSAndrea Arcangeli khugepaged_loop(); 2276a7d6e4ecSAndrea Arcangeli VM_BUG_ON(khugepaged_thread != current); 2277ba76149fSAndrea Arcangeli 2278ba76149fSAndrea Arcangeli mutex_lock(&khugepaged_mutex); 2279ba76149fSAndrea Arcangeli if (!khugepaged_enabled()) 2280ba76149fSAndrea Arcangeli break; 2281878aee7dSAndrea Arcangeli if (unlikely(kthread_should_stop())) 2282878aee7dSAndrea Arcangeli break; 2283ba76149fSAndrea Arcangeli } 2284ba76149fSAndrea Arcangeli 2285ba76149fSAndrea Arcangeli spin_lock(&khugepaged_mm_lock); 2286ba76149fSAndrea Arcangeli mm_slot = khugepaged_scan.mm_slot; 2287ba76149fSAndrea Arcangeli khugepaged_scan.mm_slot = NULL; 2288ba76149fSAndrea Arcangeli if (mm_slot) 2289ba76149fSAndrea Arcangeli collect_mm_slot(mm_slot); 2290ba76149fSAndrea Arcangeli spin_unlock(&khugepaged_mm_lock); 2291ba76149fSAndrea Arcangeli 2292ba76149fSAndrea Arcangeli khugepaged_thread = NULL; 2293ba76149fSAndrea Arcangeli mutex_unlock(&khugepaged_mutex); 2294ba76149fSAndrea Arcangeli 2295ba76149fSAndrea Arcangeli return 0; 2296ba76149fSAndrea Arcangeli } 2297ba76149fSAndrea Arcangeli 229871e3aac0SAndrea Arcangeli void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd) 229971e3aac0SAndrea Arcangeli { 230071e3aac0SAndrea Arcangeli struct page *page; 230171e3aac0SAndrea Arcangeli 230271e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 230371e3aac0SAndrea Arcangeli if (unlikely(!pmd_trans_huge(*pmd))) { 230471e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 230571e3aac0SAndrea Arcangeli return; 230671e3aac0SAndrea Arcangeli } 230771e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 230871e3aac0SAndrea Arcangeli VM_BUG_ON(!page_count(page)); 230971e3aac0SAndrea Arcangeli get_page(page); 231071e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 231171e3aac0SAndrea Arcangeli 231271e3aac0SAndrea Arcangeli split_huge_page(page); 231371e3aac0SAndrea Arcangeli 231471e3aac0SAndrea Arcangeli put_page(page); 231571e3aac0SAndrea Arcangeli BUG_ON(pmd_trans_huge(*pmd)); 231671e3aac0SAndrea Arcangeli } 231794fcc585SAndrea Arcangeli 231894fcc585SAndrea Arcangeli static void split_huge_page_address(struct mm_struct *mm, 231994fcc585SAndrea Arcangeli unsigned long address) 232094fcc585SAndrea Arcangeli { 232194fcc585SAndrea Arcangeli pgd_t *pgd; 232294fcc585SAndrea Arcangeli pud_t *pud; 232394fcc585SAndrea Arcangeli pmd_t *pmd; 232494fcc585SAndrea Arcangeli 232594fcc585SAndrea Arcangeli VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); 232694fcc585SAndrea Arcangeli 232794fcc585SAndrea Arcangeli pgd = pgd_offset(mm, address); 232894fcc585SAndrea Arcangeli if (!pgd_present(*pgd)) 232994fcc585SAndrea Arcangeli return; 233094fcc585SAndrea Arcangeli 233194fcc585SAndrea Arcangeli pud = pud_offset(pgd, address); 233294fcc585SAndrea Arcangeli if (!pud_present(*pud)) 233394fcc585SAndrea Arcangeli return; 233494fcc585SAndrea Arcangeli 233594fcc585SAndrea Arcangeli pmd = pmd_offset(pud, address); 233694fcc585SAndrea Arcangeli if (!pmd_present(*pmd)) 233794fcc585SAndrea Arcangeli return; 233894fcc585SAndrea Arcangeli /* 233994fcc585SAndrea Arcangeli * Caller holds the mmap_sem write mode, so a huge pmd cannot 234094fcc585SAndrea Arcangeli * materialize from under us. 234194fcc585SAndrea Arcangeli */ 234294fcc585SAndrea Arcangeli split_huge_page_pmd(mm, pmd); 234394fcc585SAndrea Arcangeli } 234494fcc585SAndrea Arcangeli 234594fcc585SAndrea Arcangeli void __vma_adjust_trans_huge(struct vm_area_struct *vma, 234694fcc585SAndrea Arcangeli unsigned long start, 234794fcc585SAndrea Arcangeli unsigned long end, 234894fcc585SAndrea Arcangeli long adjust_next) 234994fcc585SAndrea Arcangeli { 235094fcc585SAndrea Arcangeli /* 235194fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 235294fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 235394fcc585SAndrea Arcangeli * an huge pmd. 235494fcc585SAndrea Arcangeli */ 235594fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 235694fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 235794fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 235894fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, start); 235994fcc585SAndrea Arcangeli 236094fcc585SAndrea Arcangeli /* 236194fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 236294fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 236394fcc585SAndrea Arcangeli * an huge pmd. 236494fcc585SAndrea Arcangeli */ 236594fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 236694fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 236794fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 236894fcc585SAndrea Arcangeli split_huge_page_address(vma->vm_mm, end); 236994fcc585SAndrea Arcangeli 237094fcc585SAndrea Arcangeli /* 237194fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 237294fcc585SAndrea Arcangeli * vm_next->vm_start isn't page aligned and it could previously 237394fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 237494fcc585SAndrea Arcangeli */ 237594fcc585SAndrea Arcangeli if (adjust_next > 0) { 237694fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 237794fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 237894fcc585SAndrea Arcangeli nstart += adjust_next << PAGE_SHIFT; 237994fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 238094fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 238194fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 238294fcc585SAndrea Arcangeli split_huge_page_address(next->vm_mm, nstart); 238394fcc585SAndrea Arcangeli } 238494fcc585SAndrea Arcangeli } 2385