120c8ccb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 271e3aac0SAndrea Arcangeli /* 371e3aac0SAndrea Arcangeli * Copyright (C) 2009 Red Hat, Inc. 471e3aac0SAndrea Arcangeli */ 571e3aac0SAndrea Arcangeli 6ae3a8c1cSAndrew Morton #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 7ae3a8c1cSAndrew Morton 871e3aac0SAndrea Arcangeli #include <linux/mm.h> 971e3aac0SAndrea Arcangeli #include <linux/sched.h> 10f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 116a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 1271e3aac0SAndrea Arcangeli #include <linux/highmem.h> 1371e3aac0SAndrea Arcangeli #include <linux/hugetlb.h> 1471e3aac0SAndrea Arcangeli #include <linux/mmu_notifier.h> 1571e3aac0SAndrea Arcangeli #include <linux/rmap.h> 1671e3aac0SAndrea Arcangeli #include <linux/swap.h> 1797ae1749SKirill A. Shutemov #include <linux/shrinker.h> 18ba76149fSAndrea Arcangeli #include <linux/mm_inline.h> 19e9b61f19SKirill A. Shutemov #include <linux/swapops.h> 204897c765SMatthew Wilcox #include <linux/dax.h> 21ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 22878aee7dSAndrea Arcangeli #include <linux/freezer.h> 23f25748e3SDan Williams #include <linux/pfn_t.h> 24a664b2d8SAndrea Arcangeli #include <linux/mman.h> 253565fce3SDan Williams #include <linux/memremap.h> 26325adeb5SRalf Baechle #include <linux/pagemap.h> 2749071d43SKirill A. Shutemov #include <linux/debugfs.h> 284daae3b4SMel Gorman #include <linux/migrate.h> 2943b5fbbdSSasha Levin #include <linux/hashtable.h> 306b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 3133c3fc71SVladimir Davydov #include <linux/page_idle.h> 32baa355fdSKirill A. Shutemov #include <linux/shmem_fs.h> 336b31d595SMichal Hocko #include <linux/oom.h> 3498fa15f3SAnshuman Khandual #include <linux/numa.h> 35f7da677bSVlastimil Babka #include <linux/page_owner.h> 3697ae1749SKirill A. Shutemov 3771e3aac0SAndrea Arcangeli #include <asm/tlb.h> 3871e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 3971e3aac0SAndrea Arcangeli #include "internal.h" 4071e3aac0SAndrea Arcangeli 41ba76149fSAndrea Arcangeli /* 42b14d595aSMichael DeGuzis * By default, transparent hugepage support is disabled in order to avoid 43b14d595aSMichael DeGuzis * risking an increased memory footprint for applications that are not 44b14d595aSMichael DeGuzis * guaranteed to benefit from it. When transparent hugepage support is 45b14d595aSMichael DeGuzis * enabled, it is for all mappings, and khugepaged scans all mappings. 468bfa3f9aSJianguo Wu * Defrag is invoked by khugepaged hugepage allocations and by page faults 478bfa3f9aSJianguo Wu * for all hugepage allocations. 48ba76149fSAndrea Arcangeli */ 4971e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 5013ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 51ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 5213ece886SAndrea Arcangeli #endif 5313ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 5413ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 5513ece886SAndrea Arcangeli #endif 56444eb2a4SMel Gorman (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| 5779da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 5879da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 59ba76149fSAndrea Arcangeli 609a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker; 61f000565aSAndrea Arcangeli 6297ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 6356873f43SWang, Yalin struct page *huge_zero_page __read_mostly; 644a6c1297SKirill A. Shutemov 657635d9cbSMichal Hocko bool transparent_hugepage_enabled(struct vm_area_struct *vma) 667635d9cbSMichal Hocko { 67c0630669SYang Shi /* The addr is used to check if the vma size fits */ 68c0630669SYang Shi unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE; 69c0630669SYang Shi 70c0630669SYang Shi if (!transhuge_vma_suitable(vma, addr)) 71c0630669SYang Shi return false; 727635d9cbSMichal Hocko if (vma_is_anonymous(vma)) 737635d9cbSMichal Hocko return __transparent_hugepage_enabled(vma); 74c0630669SYang Shi if (vma_is_shmem(vma)) 75c0630669SYang Shi return shmem_huge_enabled(vma); 767635d9cbSMichal Hocko 777635d9cbSMichal Hocko return false; 787635d9cbSMichal Hocko } 797635d9cbSMichal Hocko 806fcb52a5SAaron Lu static struct page *get_huge_zero_page(void) 8197ae1749SKirill A. Shutemov { 8297ae1749SKirill A. Shutemov struct page *zero_page; 8397ae1749SKirill A. Shutemov retry: 8497ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 854db0c3c2SJason Low return READ_ONCE(huge_zero_page); 8697ae1749SKirill A. Shutemov 8797ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 8897ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 89d8a8e1f0SKirill A. Shutemov if (!zero_page) { 90d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 915918d10aSKirill A. Shutemov return NULL; 92d8a8e1f0SKirill A. Shutemov } 93d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC); 9497ae1749SKirill A. Shutemov preempt_disable(); 955918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 9697ae1749SKirill A. Shutemov preempt_enable(); 975ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 9897ae1749SKirill A. Shutemov goto retry; 9997ae1749SKirill A. Shutemov } 10097ae1749SKirill A. Shutemov 10197ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 10297ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 10397ae1749SKirill A. Shutemov preempt_enable(); 1044db0c3c2SJason Low return READ_ONCE(huge_zero_page); 10597ae1749SKirill A. Shutemov } 10697ae1749SKirill A. Shutemov 1076fcb52a5SAaron Lu static void put_huge_zero_page(void) 10897ae1749SKirill A. Shutemov { 10997ae1749SKirill A. Shutemov /* 11097ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 11197ae1749SKirill A. Shutemov * last reference. 11297ae1749SKirill A. Shutemov */ 11397ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 11497ae1749SKirill A. Shutemov } 11597ae1749SKirill A. Shutemov 1166fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 1176fcb52a5SAaron Lu { 1186fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1196fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1206fcb52a5SAaron Lu 1216fcb52a5SAaron Lu if (!get_huge_zero_page()) 1226fcb52a5SAaron Lu return NULL; 1236fcb52a5SAaron Lu 1246fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1256fcb52a5SAaron Lu put_huge_zero_page(); 1266fcb52a5SAaron Lu 1276fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1286fcb52a5SAaron Lu } 1296fcb52a5SAaron Lu 1306fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 1316fcb52a5SAaron Lu { 1326fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1336fcb52a5SAaron Lu put_huge_zero_page(); 1346fcb52a5SAaron Lu } 1356fcb52a5SAaron Lu 13648896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 13797ae1749SKirill A. Shutemov struct shrink_control *sc) 13897ae1749SKirill A. Shutemov { 13997ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 14097ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 14148896466SGlauber Costa } 14297ae1749SKirill A. Shutemov 14348896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 14448896466SGlauber Costa struct shrink_control *sc) 14548896466SGlauber Costa { 14697ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 1475918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 1485918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 1495ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 15048896466SGlauber Costa return HPAGE_PMD_NR; 15197ae1749SKirill A. Shutemov } 15297ae1749SKirill A. Shutemov 15397ae1749SKirill A. Shutemov return 0; 15497ae1749SKirill A. Shutemov } 15597ae1749SKirill A. Shutemov 15697ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 15748896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 15848896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 15997ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 16097ae1749SKirill A. Shutemov }; 16197ae1749SKirill A. Shutemov 16271e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 16371e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 16471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 16571e3aac0SAndrea Arcangeli { 166444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 167444eb2a4SMel Gorman return sprintf(buf, "[always] madvise never\n"); 168444eb2a4SMel Gorman else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) 169444eb2a4SMel Gorman return sprintf(buf, "always [madvise] never\n"); 170444eb2a4SMel Gorman else 171444eb2a4SMel Gorman return sprintf(buf, "always madvise [never]\n"); 17271e3aac0SAndrea Arcangeli } 173444eb2a4SMel Gorman 17471e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 17571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 17671e3aac0SAndrea Arcangeli const char *buf, size_t count) 17771e3aac0SAndrea Arcangeli { 17821440d7eSDavid Rientjes ssize_t ret = count; 179ba76149fSAndrea Arcangeli 180f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 18121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 18221440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 183f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 18421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 18521440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 186f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 18721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 18821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 18921440d7eSDavid Rientjes } else 19021440d7eSDavid Rientjes ret = -EINVAL; 191ba76149fSAndrea Arcangeli 192ba76149fSAndrea Arcangeli if (ret > 0) { 193b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 194ba76149fSAndrea Arcangeli if (err) 195ba76149fSAndrea Arcangeli ret = err; 196ba76149fSAndrea Arcangeli } 197ba76149fSAndrea Arcangeli return ret; 19871e3aac0SAndrea Arcangeli } 19971e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 20071e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 20171e3aac0SAndrea Arcangeli 202b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 20371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 20471e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 20571e3aac0SAndrea Arcangeli { 206e27e6151SBen Hutchings return sprintf(buf, "%d\n", 207e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 20871e3aac0SAndrea Arcangeli } 209e27e6151SBen Hutchings 210b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 21171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 21271e3aac0SAndrea Arcangeli const char *buf, size_t count, 21371e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 21471e3aac0SAndrea Arcangeli { 215e27e6151SBen Hutchings unsigned long value; 216e27e6151SBen Hutchings int ret; 217e27e6151SBen Hutchings 218e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 219e27e6151SBen Hutchings if (ret < 0) 220e27e6151SBen Hutchings return ret; 221e27e6151SBen Hutchings if (value > 1) 22271e3aac0SAndrea Arcangeli return -EINVAL; 22371e3aac0SAndrea Arcangeli 224e27e6151SBen Hutchings if (value) 225e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 226e27e6151SBen Hutchings else 227e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 228e27e6151SBen Hutchings 22971e3aac0SAndrea Arcangeli return count; 23071e3aac0SAndrea Arcangeli } 23171e3aac0SAndrea Arcangeli 23271e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 23371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 23471e3aac0SAndrea Arcangeli { 235444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 23621440d7eSDavid Rientjes return sprintf(buf, "[always] defer defer+madvise madvise never\n"); 237444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 23821440d7eSDavid Rientjes return sprintf(buf, "always [defer] defer+madvise madvise never\n"); 23921440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 24021440d7eSDavid Rientjes return sprintf(buf, "always defer [defer+madvise] madvise never\n"); 24121440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 24221440d7eSDavid Rientjes return sprintf(buf, "always defer defer+madvise [madvise] never\n"); 24321440d7eSDavid Rientjes return sprintf(buf, "always defer defer+madvise madvise [never]\n"); 24471e3aac0SAndrea Arcangeli } 24521440d7eSDavid Rientjes 24671e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 24771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 24871e3aac0SAndrea Arcangeli const char *buf, size_t count) 24971e3aac0SAndrea Arcangeli { 250f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 25121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 25221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 25321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 25421440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 255f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer+madvise")) { 25621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 25721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 25821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 25921440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 260f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer")) { 2614fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 2624fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 2634fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 2644fad7fb6SDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 265f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 26621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 26721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 26821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 26921440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 270f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 27121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 27221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 27321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 27421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 27521440d7eSDavid Rientjes } else 27621440d7eSDavid Rientjes return -EINVAL; 27721440d7eSDavid Rientjes 27821440d7eSDavid Rientjes return count; 27971e3aac0SAndrea Arcangeli } 28071e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 28171e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 28271e3aac0SAndrea Arcangeli 28379da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 28479da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 28579da5407SKirill A. Shutemov { 286b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 28779da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 28879da5407SKirill A. Shutemov } 28979da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 29079da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 29179da5407SKirill A. Shutemov { 292b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 29379da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 29479da5407SKirill A. Shutemov } 29579da5407SKirill A. Shutemov static struct kobj_attribute use_zero_page_attr = 29679da5407SKirill A. Shutemov __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); 29749920d28SHugh Dickins 29849920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 29949920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 30049920d28SHugh Dickins { 30149920d28SHugh Dickins return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); 30249920d28SHugh Dickins } 30349920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 30449920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 30549920d28SHugh Dickins 30671e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 30771e3aac0SAndrea Arcangeli static ssize_t debug_cow_show(struct kobject *kobj, 30871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 30971e3aac0SAndrea Arcangeli { 310b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 31171e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 31271e3aac0SAndrea Arcangeli } 31371e3aac0SAndrea Arcangeli static ssize_t debug_cow_store(struct kobject *kobj, 31471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 31571e3aac0SAndrea Arcangeli const char *buf, size_t count) 31671e3aac0SAndrea Arcangeli { 317b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 31871e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 31971e3aac0SAndrea Arcangeli } 32071e3aac0SAndrea Arcangeli static struct kobj_attribute debug_cow_attr = 32171e3aac0SAndrea Arcangeli __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); 32271e3aac0SAndrea Arcangeli #endif /* CONFIG_DEBUG_VM */ 32371e3aac0SAndrea Arcangeli 32471e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 32571e3aac0SAndrea Arcangeli &enabled_attr.attr, 32671e3aac0SAndrea Arcangeli &defrag_attr.attr, 32779da5407SKirill A. Shutemov &use_zero_page_attr.attr, 32849920d28SHugh Dickins &hpage_pmd_size_attr.attr, 329e496cf3dSKirill A. Shutemov #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) 3305a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 3315a6e75f8SKirill A. Shutemov #endif 33271e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 33371e3aac0SAndrea Arcangeli &debug_cow_attr.attr, 33471e3aac0SAndrea Arcangeli #endif 33571e3aac0SAndrea Arcangeli NULL, 33671e3aac0SAndrea Arcangeli }; 33771e3aac0SAndrea Arcangeli 3388aa95a21SArvind Yadav static const struct attribute_group hugepage_attr_group = { 33971e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 340ba76149fSAndrea Arcangeli }; 341ba76149fSAndrea Arcangeli 342569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 343569e5590SShaohua Li { 344569e5590SShaohua Li int err; 345569e5590SShaohua Li 346569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 347569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 348ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 349569e5590SShaohua Li return -ENOMEM; 350569e5590SShaohua Li } 351569e5590SShaohua Li 352569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 353569e5590SShaohua Li if (err) { 354ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 355569e5590SShaohua Li goto delete_obj; 356569e5590SShaohua Li } 357569e5590SShaohua Li 358569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 359569e5590SShaohua Li if (err) { 360ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 361569e5590SShaohua Li goto remove_hp_group; 362569e5590SShaohua Li } 363569e5590SShaohua Li 364569e5590SShaohua Li return 0; 365569e5590SShaohua Li 366569e5590SShaohua Li remove_hp_group: 367569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 368569e5590SShaohua Li delete_obj: 369569e5590SShaohua Li kobject_put(*hugepage_kobj); 370569e5590SShaohua Li return err; 371569e5590SShaohua Li } 372569e5590SShaohua Li 373569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 374569e5590SShaohua Li { 375569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 376569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 377569e5590SShaohua Li kobject_put(hugepage_kobj); 378569e5590SShaohua Li } 379569e5590SShaohua Li #else 380569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 381569e5590SShaohua Li { 382569e5590SShaohua Li return 0; 383569e5590SShaohua Li } 384569e5590SShaohua Li 385569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 386569e5590SShaohua Li { 387569e5590SShaohua Li } 38871e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 38971e3aac0SAndrea Arcangeli 39071e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 39171e3aac0SAndrea Arcangeli { 39271e3aac0SAndrea Arcangeli int err; 393569e5590SShaohua Li struct kobject *hugepage_kobj; 39471e3aac0SAndrea Arcangeli 3954b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 3964b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 397569e5590SShaohua Li return -EINVAL; 3984b7167b9SAndrea Arcangeli } 3994b7167b9SAndrea Arcangeli 400ff20c2e0SKirill A. Shutemov /* 401ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 402ff20c2e0SKirill A. Shutemov */ 403ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); 404ff20c2e0SKirill A. Shutemov /* 405ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 406ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 407ff20c2e0SKirill A. Shutemov */ 408ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 409ff20c2e0SKirill A. Shutemov 410569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 411569e5590SShaohua Li if (err) 41265ebb64fSKirill A. Shutemov goto err_sysfs; 413ba76149fSAndrea Arcangeli 414b46e756fSKirill A. Shutemov err = khugepaged_init(); 415ba76149fSAndrea Arcangeli if (err) 41665ebb64fSKirill A. Shutemov goto err_slab; 417ba76149fSAndrea Arcangeli 41865ebb64fSKirill A. Shutemov err = register_shrinker(&huge_zero_page_shrinker); 41965ebb64fSKirill A. Shutemov if (err) 42065ebb64fSKirill A. Shutemov goto err_hzp_shrinker; 4219a982250SKirill A. Shutemov err = register_shrinker(&deferred_split_shrinker); 4229a982250SKirill A. Shutemov if (err) 4239a982250SKirill A. Shutemov goto err_split_shrinker; 42497ae1749SKirill A. Shutemov 42597562cd2SRik van Riel /* 42697562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 42797562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 42897562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 42997562cd2SRik van Riel */ 430ca79b0c2SArun KS if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { 43197562cd2SRik van Riel transparent_hugepage_flags = 0; 43279553da2SKirill A. Shutemov return 0; 43379553da2SKirill A. Shutemov } 43497562cd2SRik van Riel 43579553da2SKirill A. Shutemov err = start_stop_khugepaged(); 43665ebb64fSKirill A. Shutemov if (err) 43765ebb64fSKirill A. Shutemov goto err_khugepaged; 438ba76149fSAndrea Arcangeli 439569e5590SShaohua Li return 0; 44065ebb64fSKirill A. Shutemov err_khugepaged: 4419a982250SKirill A. Shutemov unregister_shrinker(&deferred_split_shrinker); 4429a982250SKirill A. Shutemov err_split_shrinker: 44365ebb64fSKirill A. Shutemov unregister_shrinker(&huge_zero_page_shrinker); 44465ebb64fSKirill A. Shutemov err_hzp_shrinker: 445b46e756fSKirill A. Shutemov khugepaged_destroy(); 44665ebb64fSKirill A. Shutemov err_slab: 447569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 44865ebb64fSKirill A. Shutemov err_sysfs: 449ba76149fSAndrea Arcangeli return err; 45071e3aac0SAndrea Arcangeli } 451a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 45271e3aac0SAndrea Arcangeli 45371e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 45471e3aac0SAndrea Arcangeli { 45571e3aac0SAndrea Arcangeli int ret = 0; 45671e3aac0SAndrea Arcangeli if (!str) 45771e3aac0SAndrea Arcangeli goto out; 45871e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 45971e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 46071e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46171e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 46271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46371e3aac0SAndrea Arcangeli ret = 1; 46471e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 46571e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 46671e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46771e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 46871e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46971e3aac0SAndrea Arcangeli ret = 1; 47071e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 47171e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 47271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 47371e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 47471e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 47571e3aac0SAndrea Arcangeli ret = 1; 47671e3aac0SAndrea Arcangeli } 47771e3aac0SAndrea Arcangeli out: 47871e3aac0SAndrea Arcangeli if (!ret) 479ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 48071e3aac0SAndrea Arcangeli return ret; 48171e3aac0SAndrea Arcangeli } 48271e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 48371e3aac0SAndrea Arcangeli 484f55e1014SLinus Torvalds pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 48571e3aac0SAndrea Arcangeli { 486f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 48771e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 48871e3aac0SAndrea Arcangeli return pmd; 48971e3aac0SAndrea Arcangeli } 49071e3aac0SAndrea Arcangeli 49187eaceb3SYang Shi #ifdef CONFIG_MEMCG 49287eaceb3SYang Shi static inline struct deferred_split *get_deferred_split_queue(struct page *page) 4939a982250SKirill A. Shutemov { 49487eaceb3SYang Shi struct mem_cgroup *memcg = compound_head(page)->mem_cgroup; 49587eaceb3SYang Shi struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); 49687eaceb3SYang Shi 49787eaceb3SYang Shi if (memcg) 49887eaceb3SYang Shi return &memcg->deferred_split_queue; 49987eaceb3SYang Shi else 50087eaceb3SYang Shi return &pgdat->deferred_split_queue; 5019a982250SKirill A. Shutemov } 50287eaceb3SYang Shi #else 50387eaceb3SYang Shi static inline struct deferred_split *get_deferred_split_queue(struct page *page) 50487eaceb3SYang Shi { 50587eaceb3SYang Shi struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); 50687eaceb3SYang Shi 50787eaceb3SYang Shi return &pgdat->deferred_split_queue; 50887eaceb3SYang Shi } 50987eaceb3SYang Shi #endif 5109a982250SKirill A. Shutemov 5119a982250SKirill A. Shutemov void prep_transhuge_page(struct page *page) 5129a982250SKirill A. Shutemov { 5139a982250SKirill A. Shutemov /* 5149a982250SKirill A. Shutemov * we use page->mapping and page->indexlru in second tail page 5159a982250SKirill A. Shutemov * as list_head: assuming THP order >= 2 5169a982250SKirill A. Shutemov */ 5179a982250SKirill A. Shutemov 5189a982250SKirill A. Shutemov INIT_LIST_HEAD(page_deferred_list(page)); 5199a982250SKirill A. Shutemov set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); 5209a982250SKirill A. Shutemov } 5219a982250SKirill A. Shutemov 522005ba37cSSean Christopherson bool is_transparent_hugepage(struct page *page) 523005ba37cSSean Christopherson { 524005ba37cSSean Christopherson if (!PageCompound(page)) 525005ba37cSSean Christopherson return 0; 526005ba37cSSean Christopherson 527005ba37cSSean Christopherson page = compound_head(page); 528005ba37cSSean Christopherson return is_huge_zero_page(page) || 529005ba37cSSean Christopherson page[1].compound_dtor == TRANSHUGE_PAGE_DTOR; 530005ba37cSSean Christopherson } 531005ba37cSSean Christopherson EXPORT_SYMBOL_GPL(is_transparent_hugepage); 532005ba37cSSean Christopherson 53397d3d0f9SKirill A. Shutemov static unsigned long __thp_get_unmapped_area(struct file *filp, 53497d3d0f9SKirill A. Shutemov unsigned long addr, unsigned long len, 53574d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 53674d2fad1SToshi Kani { 53774d2fad1SToshi Kani loff_t off_end = off + len; 53874d2fad1SToshi Kani loff_t off_align = round_up(off, size); 53997d3d0f9SKirill A. Shutemov unsigned long len_pad, ret; 54074d2fad1SToshi Kani 54174d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 54274d2fad1SToshi Kani return 0; 54374d2fad1SToshi Kani 54474d2fad1SToshi Kani len_pad = len + size; 54574d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 54674d2fad1SToshi Kani return 0; 54774d2fad1SToshi Kani 54897d3d0f9SKirill A. Shutemov ret = current->mm->get_unmapped_area(filp, addr, len_pad, 54974d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 55097d3d0f9SKirill A. Shutemov 55197d3d0f9SKirill A. Shutemov /* 55297d3d0f9SKirill A. Shutemov * The failure might be due to length padding. The caller will retry 55397d3d0f9SKirill A. Shutemov * without the padding. 55497d3d0f9SKirill A. Shutemov */ 55597d3d0f9SKirill A. Shutemov if (IS_ERR_VALUE(ret)) 55674d2fad1SToshi Kani return 0; 55774d2fad1SToshi Kani 55897d3d0f9SKirill A. Shutemov /* 55997d3d0f9SKirill A. Shutemov * Do not try to align to THP boundary if allocation at the address 56097d3d0f9SKirill A. Shutemov * hint succeeds. 56197d3d0f9SKirill A. Shutemov */ 56297d3d0f9SKirill A. Shutemov if (ret == addr) 56374d2fad1SToshi Kani return addr; 56497d3d0f9SKirill A. Shutemov 56597d3d0f9SKirill A. Shutemov ret += (off - ret) & (size - 1); 56697d3d0f9SKirill A. Shutemov return ret; 56774d2fad1SToshi Kani } 56874d2fad1SToshi Kani 56974d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 57074d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 57174d2fad1SToshi Kani { 57297d3d0f9SKirill A. Shutemov unsigned long ret; 57374d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 57474d2fad1SToshi Kani 57574d2fad1SToshi Kani if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) 57674d2fad1SToshi Kani goto out; 57774d2fad1SToshi Kani 57897d3d0f9SKirill A. Shutemov ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); 57997d3d0f9SKirill A. Shutemov if (ret) 58097d3d0f9SKirill A. Shutemov return ret; 58174d2fad1SToshi Kani out: 58274d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 58374d2fad1SToshi Kani } 58474d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 58574d2fad1SToshi Kani 5862b740303SSouptick Joarder static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, 5872b740303SSouptick Joarder struct page *page, gfp_t gfp) 58871e3aac0SAndrea Arcangeli { 58982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 59000501b53SJohannes Weiner struct mem_cgroup *memcg; 59171e3aac0SAndrea Arcangeli pgtable_t pgtable; 59282b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 5932b740303SSouptick Joarder vm_fault_t ret = 0; 59471e3aac0SAndrea Arcangeli 595309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 59600501b53SJohannes Weiner 5972cf85583STejun Heo if (mem_cgroup_try_charge_delay(page, vma->vm_mm, gfp, &memcg, true)) { 5986b251fc9SAndrea Arcangeli put_page(page); 5996b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 6006b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 6016b251fc9SAndrea Arcangeli } 60271e3aac0SAndrea Arcangeli 6034cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 60400501b53SJohannes Weiner if (unlikely(!pgtable)) { 6056b31d595SMichal Hocko ret = VM_FAULT_OOM; 6066b31d595SMichal Hocko goto release; 60700501b53SJohannes Weiner } 60800501b53SJohannes Weiner 609c79b57e4SHuang Ying clear_huge_page(page, vmf->address, HPAGE_PMD_NR); 61052f37629SMinchan Kim /* 61152f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 61252f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 61352f37629SMinchan Kim * write. 61452f37629SMinchan Kim */ 61571e3aac0SAndrea Arcangeli __SetPageUptodate(page); 61671e3aac0SAndrea Arcangeli 61782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 61882b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 6196b31d595SMichal Hocko goto unlock_release; 62071e3aac0SAndrea Arcangeli } else { 62171e3aac0SAndrea Arcangeli pmd_t entry; 6226b251fc9SAndrea Arcangeli 6236b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 6246b31d595SMichal Hocko if (ret) 6256b31d595SMichal Hocko goto unlock_release; 6266b31d595SMichal Hocko 6276b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 6286b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 6292b740303SSouptick Joarder vm_fault_t ret2; 6306b251fc9SAndrea Arcangeli 63182b0f8c3SJan Kara spin_unlock(vmf->ptl); 632f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, true); 6336b251fc9SAndrea Arcangeli put_page(page); 634bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 6352b740303SSouptick Joarder ret2 = handle_userfault(vmf, VM_UFFD_MISSING); 6362b740303SSouptick Joarder VM_BUG_ON(ret2 & VM_FAULT_FALLBACK); 6372b740303SSouptick Joarder return ret2; 6386b251fc9SAndrea Arcangeli } 6396b251fc9SAndrea Arcangeli 6403122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 641f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 642d281ee61SKirill A. Shutemov page_add_new_anon_rmap(page, vma, haddr, true); 643f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(page, memcg, false, true); 64400501b53SJohannes Weiner lru_cache_add_active_or_unevictable(page, vma); 64582b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 64682b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 647bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 648c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 64982b0f8c3SJan Kara spin_unlock(vmf->ptl); 6506b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 6511ff9e6e1SChris Down count_memcg_events(memcg, THP_FAULT_ALLOC, 1); 65271e3aac0SAndrea Arcangeli } 65371e3aac0SAndrea Arcangeli 654aa2e878eSDavid Rientjes return 0; 6556b31d595SMichal Hocko unlock_release: 6566b31d595SMichal Hocko spin_unlock(vmf->ptl); 6576b31d595SMichal Hocko release: 6586b31d595SMichal Hocko if (pgtable) 6596b31d595SMichal Hocko pte_free(vma->vm_mm, pgtable); 6606b31d595SMichal Hocko mem_cgroup_cancel_charge(page, memcg, true); 6616b31d595SMichal Hocko put_page(page); 6626b31d595SMichal Hocko return ret; 6636b31d595SMichal Hocko 66471e3aac0SAndrea Arcangeli } 66571e3aac0SAndrea Arcangeli 666444eb2a4SMel Gorman /* 66721440d7eSDavid Rientjes * always: directly stall for all thp allocations 66821440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 66921440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 67021440d7eSDavid Rientjes * fail if not immediately available 67121440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 67221440d7eSDavid Rientjes * available 67321440d7eSDavid Rientjes * never: never stall for any thp allocation 674444eb2a4SMel Gorman */ 67519deb769SDavid Rientjes static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) 6760bbbc0b3SAndrea Arcangeli { 67721440d7eSDavid Rientjes const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); 67889c83fb5SMichal Hocko 679ac79f78dSDavid Rientjes /* Always do synchronous compaction */ 68021440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 681a8282608SAndrea Arcangeli return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 682ac79f78dSDavid Rientjes 683ac79f78dSDavid Rientjes /* Kick kcompactd and fail quickly */ 68421440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 68519deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 686ac79f78dSDavid Rientjes 687ac79f78dSDavid Rientjes /* Synchronous compaction if madvised, otherwise kick kcompactd */ 68821440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 68919deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 69019deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 691ac79f78dSDavid Rientjes __GFP_KSWAPD_RECLAIM); 692ac79f78dSDavid Rientjes 693ac79f78dSDavid Rientjes /* Only do synchronous compaction if madvised */ 69421440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 69519deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 69619deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); 697ac79f78dSDavid Rientjes 69819deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT; 699444eb2a4SMel Gorman } 700444eb2a4SMel Gorman 701c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 702d295e341SKirill A. Shutemov static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 70397ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 7045918d10aSKirill A. Shutemov struct page *zero_page) 705fc9fe822SKirill A. Shutemov { 706fc9fe822SKirill A. Shutemov pmd_t entry; 7077c414164SAndrew Morton if (!pmd_none(*pmd)) 7087c414164SAndrew Morton return false; 7095918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 710fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 71112c9d70bSMatthew Wilcox if (pgtable) 7126b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 713fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 714c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 7157c414164SAndrew Morton return true; 716fc9fe822SKirill A. Shutemov } 717fc9fe822SKirill A. Shutemov 7182b740303SSouptick Joarder vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) 71971e3aac0SAndrea Arcangeli { 72082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 721077fcf11SAneesh Kumar K.V gfp_t gfp; 72271e3aac0SAndrea Arcangeli struct page *page; 72382b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 72471e3aac0SAndrea Arcangeli 72543675e6fSYang Shi if (!transhuge_vma_suitable(vma, haddr)) 726c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 72771e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 72871e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 7296d50e60cSDavid Rientjes if (unlikely(khugepaged_enter(vma, vma->vm_flags))) 730ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 73182b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 732bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 73379da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 73480371957SKirill A. Shutemov pgtable_t pgtable; 7355918d10aSKirill A. Shutemov struct page *zero_page; 7363ea41e62SKirill A. Shutemov bool set; 7372b740303SSouptick Joarder vm_fault_t ret; 7384cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 73980371957SKirill A. Shutemov if (unlikely(!pgtable)) 74080371957SKirill A. Shutemov return VM_FAULT_OOM; 7416fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 7425918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 743bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 74497ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 745c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 74697ae1749SKirill A. Shutemov } 74782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 7486b251fc9SAndrea Arcangeli ret = 0; 7496b251fc9SAndrea Arcangeli set = false; 75082b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 7516b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 7526b31d595SMichal Hocko if (ret) { 7536b31d595SMichal Hocko spin_unlock(vmf->ptl); 7546b31d595SMichal Hocko } else if (userfaultfd_missing(vma)) { 75582b0f8c3SJan Kara spin_unlock(vmf->ptl); 75682b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 7576b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 7586b251fc9SAndrea Arcangeli } else { 759bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 76082b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 76182b0f8c3SJan Kara spin_unlock(vmf->ptl); 7626b251fc9SAndrea Arcangeli set = true; 7636b251fc9SAndrea Arcangeli } 7646b251fc9SAndrea Arcangeli } else 76582b0f8c3SJan Kara spin_unlock(vmf->ptl); 7666fcb52a5SAaron Lu if (!set) 767bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 7686b251fc9SAndrea Arcangeli return ret; 76980371957SKirill A. Shutemov } 77019deb769SDavid Rientjes gfp = alloc_hugepage_direct_gfpmask(vma); 77119deb769SDavid Rientjes page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); 77281ab4201SAndi Kleen if (unlikely(!page)) { 77381ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 774c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 77581ab4201SAndi Kleen } 7769a982250SKirill A. Shutemov prep_transhuge_page(page); 77782b0f8c3SJan Kara return __do_huge_pmd_anonymous_page(vmf, page, gfp); 77871e3aac0SAndrea Arcangeli } 77971e3aac0SAndrea Arcangeli 780ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 7813b6521f5SOliver O'Halloran pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, 7823b6521f5SOliver O'Halloran pgtable_t pgtable) 7835cad465dSMatthew Wilcox { 7845cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 7855cad465dSMatthew Wilcox pmd_t entry; 7865cad465dSMatthew Wilcox spinlock_t *ptl; 7875cad465dSMatthew Wilcox 7885cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 789c6f3c5eeSAneesh Kumar K.V if (!pmd_none(*pmd)) { 790c6f3c5eeSAneesh Kumar K.V if (write) { 791c6f3c5eeSAneesh Kumar K.V if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { 792c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); 793c6f3c5eeSAneesh Kumar K.V goto out_unlock; 794c6f3c5eeSAneesh Kumar K.V } 795c6f3c5eeSAneesh Kumar K.V entry = pmd_mkyoung(*pmd); 796c6f3c5eeSAneesh Kumar K.V entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 797c6f3c5eeSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) 798c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 799c6f3c5eeSAneesh Kumar K.V } 800c6f3c5eeSAneesh Kumar K.V 801c6f3c5eeSAneesh Kumar K.V goto out_unlock; 802c6f3c5eeSAneesh Kumar K.V } 803c6f3c5eeSAneesh Kumar K.V 804f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 805f25748e3SDan Williams if (pfn_t_devmap(pfn)) 806f25748e3SDan Williams entry = pmd_mkdevmap(entry); 8075cad465dSMatthew Wilcox if (write) { 808f55e1014SLinus Torvalds entry = pmd_mkyoung(pmd_mkdirty(entry)); 809f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(entry, vma); 8105cad465dSMatthew Wilcox } 8113b6521f5SOliver O'Halloran 8123b6521f5SOliver O'Halloran if (pgtable) { 8133b6521f5SOliver O'Halloran pgtable_trans_huge_deposit(mm, pmd, pgtable); 814c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 815c6f3c5eeSAneesh Kumar K.V pgtable = NULL; 8163b6521f5SOliver O'Halloran } 8173b6521f5SOliver O'Halloran 8185cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 8195cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 820c6f3c5eeSAneesh Kumar K.V 821c6f3c5eeSAneesh Kumar K.V out_unlock: 8225cad465dSMatthew Wilcox spin_unlock(ptl); 823c6f3c5eeSAneesh Kumar K.V if (pgtable) 824c6f3c5eeSAneesh Kumar K.V pte_free(mm, pgtable); 8255cad465dSMatthew Wilcox } 8265cad465dSMatthew Wilcox 827fce86ff5SDan Williams vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) 8285cad465dSMatthew Wilcox { 829fce86ff5SDan Williams unsigned long addr = vmf->address & PMD_MASK; 830fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 8315cad465dSMatthew Wilcox pgprot_t pgprot = vma->vm_page_prot; 8323b6521f5SOliver O'Halloran pgtable_t pgtable = NULL; 833fce86ff5SDan Williams 8345cad465dSMatthew Wilcox /* 8355cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 8365cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 8375cad465dSMatthew Wilcox * can't support a 'special' bit. 8385cad465dSMatthew Wilcox */ 839e1fb4a08SDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 840e1fb4a08SDave Jiang !pfn_t_devmap(pfn)); 8415cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 8425cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 8435cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 8445cad465dSMatthew Wilcox 8455cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 8465cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 847308a047cSBorislav Petkov 8483b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) { 8494cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 8503b6521f5SOliver O'Halloran if (!pgtable) 8513b6521f5SOliver O'Halloran return VM_FAULT_OOM; 8523b6521f5SOliver O'Halloran } 8533b6521f5SOliver O'Halloran 854308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 855308a047cSBorislav Petkov 856fce86ff5SDan Williams insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); 857ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 8585cad465dSMatthew Wilcox } 859dee41079SDan Williams EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); 8605cad465dSMatthew Wilcox 861a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 862f55e1014SLinus Torvalds static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 863a00cc7d9SMatthew Wilcox { 864f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 865a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 866a00cc7d9SMatthew Wilcox return pud; 867a00cc7d9SMatthew Wilcox } 868a00cc7d9SMatthew Wilcox 869a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 870a00cc7d9SMatthew Wilcox pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) 871a00cc7d9SMatthew Wilcox { 872a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 873a00cc7d9SMatthew Wilcox pud_t entry; 874a00cc7d9SMatthew Wilcox spinlock_t *ptl; 875a00cc7d9SMatthew Wilcox 876a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 877c6f3c5eeSAneesh Kumar K.V if (!pud_none(*pud)) { 878c6f3c5eeSAneesh Kumar K.V if (write) { 879c6f3c5eeSAneesh Kumar K.V if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { 880c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pud(*pud)); 881c6f3c5eeSAneesh Kumar K.V goto out_unlock; 882c6f3c5eeSAneesh Kumar K.V } 883c6f3c5eeSAneesh Kumar K.V entry = pud_mkyoung(*pud); 884c6f3c5eeSAneesh Kumar K.V entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); 885c6f3c5eeSAneesh Kumar K.V if (pudp_set_access_flags(vma, addr, pud, entry, 1)) 886c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pud(vma, addr, pud); 887c6f3c5eeSAneesh Kumar K.V } 888c6f3c5eeSAneesh Kumar K.V goto out_unlock; 889c6f3c5eeSAneesh Kumar K.V } 890c6f3c5eeSAneesh Kumar K.V 891a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 892a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 893a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 894a00cc7d9SMatthew Wilcox if (write) { 895f55e1014SLinus Torvalds entry = pud_mkyoung(pud_mkdirty(entry)); 896f55e1014SLinus Torvalds entry = maybe_pud_mkwrite(entry, vma); 897a00cc7d9SMatthew Wilcox } 898a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 899a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 900c6f3c5eeSAneesh Kumar K.V 901c6f3c5eeSAneesh Kumar K.V out_unlock: 902a00cc7d9SMatthew Wilcox spin_unlock(ptl); 903a00cc7d9SMatthew Wilcox } 904a00cc7d9SMatthew Wilcox 905fce86ff5SDan Williams vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) 906a00cc7d9SMatthew Wilcox { 907fce86ff5SDan Williams unsigned long addr = vmf->address & PUD_MASK; 908fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 909a00cc7d9SMatthew Wilcox pgprot_t pgprot = vma->vm_page_prot; 910fce86ff5SDan Williams 911a00cc7d9SMatthew Wilcox /* 912a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 913a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 914a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 915a00cc7d9SMatthew Wilcox */ 91662ec0d8cSDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 91762ec0d8cSDave Jiang !pfn_t_devmap(pfn)); 918a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 919a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 920a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 921a00cc7d9SMatthew Wilcox 922a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 923a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 924a00cc7d9SMatthew Wilcox 925a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 926a00cc7d9SMatthew Wilcox 927fce86ff5SDan Williams insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); 928a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 929a00cc7d9SMatthew Wilcox } 930a00cc7d9SMatthew Wilcox EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); 931a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 932a00cc7d9SMatthew Wilcox 9333565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 934a8f97366SKirill A. Shutemov pmd_t *pmd, int flags) 9353565fce3SDan Williams { 9363565fce3SDan Williams pmd_t _pmd; 9373565fce3SDan Williams 938a8f97366SKirill A. Shutemov _pmd = pmd_mkyoung(*pmd); 939a8f97366SKirill A. Shutemov if (flags & FOLL_WRITE) 940a8f97366SKirill A. Shutemov _pmd = pmd_mkdirty(_pmd); 9413565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 942a8f97366SKirill A. Shutemov pmd, _pmd, flags & FOLL_WRITE)) 9433565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 9443565fce3SDan Williams } 9453565fce3SDan Williams 9463565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 947df06b37fSKeith Busch pmd_t *pmd, int flags, struct dev_pagemap **pgmap) 9483565fce3SDan Williams { 9493565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 9503565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 9513565fce3SDan Williams struct page *page; 9523565fce3SDan Williams 9533565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 9543565fce3SDan Williams 9558310d48bSKeno Fischer /* 9568310d48bSKeno Fischer * When we COW a devmap PMD entry, we split it into PTEs, so we should 9578310d48bSKeno Fischer * not be in this function with `flags & FOLL_COW` set. 9588310d48bSKeno Fischer */ 9598310d48bSKeno Fischer WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); 9608310d48bSKeno Fischer 961f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pmd_write(*pmd)) 9623565fce3SDan Williams return NULL; 9633565fce3SDan Williams 9643565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 9653565fce3SDan Williams /* pass */; 9663565fce3SDan Williams else 9673565fce3SDan Williams return NULL; 9683565fce3SDan Williams 9693565fce3SDan Williams if (flags & FOLL_TOUCH) 970a8f97366SKirill A. Shutemov touch_pmd(vma, addr, pmd, flags); 9713565fce3SDan Williams 9723565fce3SDan Williams /* 9733565fce3SDan Williams * device mapped pages can only be returned if the 9743565fce3SDan Williams * caller will manage the page reference count. 9753565fce3SDan Williams */ 9763565fce3SDan Williams if (!(flags & FOLL_GET)) 9773565fce3SDan Williams return ERR_PTR(-EEXIST); 9783565fce3SDan Williams 9793565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 980df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 981df06b37fSKeith Busch if (!*pgmap) 9823565fce3SDan Williams return ERR_PTR(-EFAULT); 9833565fce3SDan Williams page = pfn_to_page(pfn); 9843565fce3SDan Williams get_page(page); 9853565fce3SDan Williams 9863565fce3SDan Williams return page; 9873565fce3SDan Williams } 9883565fce3SDan Williams 98971e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 99071e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 99171e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 99271e3aac0SAndrea Arcangeli { 993c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 99471e3aac0SAndrea Arcangeli struct page *src_page; 99571e3aac0SAndrea Arcangeli pmd_t pmd; 99612c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 997628d47ceSKirill A. Shutemov int ret = -ENOMEM; 99871e3aac0SAndrea Arcangeli 999628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 1000628d47ceSKirill A. Shutemov if (!vma_is_anonymous(vma)) 1001628d47ceSKirill A. Shutemov return 0; 1002628d47ceSKirill A. Shutemov 10034cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(dst_mm); 100471e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 100571e3aac0SAndrea Arcangeli goto out; 100671e3aac0SAndrea Arcangeli 1007c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 1008c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 1009c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 101071e3aac0SAndrea Arcangeli 101171e3aac0SAndrea Arcangeli ret = -EAGAIN; 101271e3aac0SAndrea Arcangeli pmd = *src_pmd; 101384c3fc4eSZi Yan 101484c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 101584c3fc4eSZi Yan if (unlikely(is_swap_pmd(pmd))) { 101684c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(pmd); 101784c3fc4eSZi Yan 101884c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(pmd)); 101984c3fc4eSZi Yan if (is_write_migration_entry(entry)) { 102084c3fc4eSZi Yan make_migration_entry_read(&entry); 102184c3fc4eSZi Yan pmd = swp_entry_to_pmd(entry); 1022ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*src_pmd)) 1023ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 102484c3fc4eSZi Yan set_pmd_at(src_mm, addr, src_pmd, pmd); 102584c3fc4eSZi Yan } 1026dd8a67f9SZi Yan add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1027af5b0f6aSKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 1028dd8a67f9SZi Yan pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 102984c3fc4eSZi Yan set_pmd_at(dst_mm, addr, dst_pmd, pmd); 103084c3fc4eSZi Yan ret = 0; 103184c3fc4eSZi Yan goto out_unlock; 103284c3fc4eSZi Yan } 103384c3fc4eSZi Yan #endif 103484c3fc4eSZi Yan 1035628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 103671e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 103771e3aac0SAndrea Arcangeli goto out_unlock; 103871e3aac0SAndrea Arcangeli } 1039fc9fe822SKirill A. Shutemov /* 1040c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 1041fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 1042fc9fe822SKirill A. Shutemov * a page table. 1043fc9fe822SKirill A. Shutemov */ 1044fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 10455918d10aSKirill A. Shutemov struct page *zero_page; 104697ae1749SKirill A. Shutemov /* 104797ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 104897ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 104997ae1749SKirill A. Shutemov * reference. 105097ae1749SKirill A. Shutemov */ 10516fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(dst_mm); 10526b251fc9SAndrea Arcangeli set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, 10535918d10aSKirill A. Shutemov zero_page); 1054fc9fe822SKirill A. Shutemov ret = 0; 1055fc9fe822SKirill A. Shutemov goto out_unlock; 1056fc9fe822SKirill A. Shutemov } 1057de466bd6SMel Gorman 105871e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 1059309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 106071e3aac0SAndrea Arcangeli get_page(src_page); 106153f9263bSKirill A. Shutemov page_dup_rmap(src_page, true); 106271e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1063c4812909SKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 10645c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 106571e3aac0SAndrea Arcangeli 106671e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 106771e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 106871e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 106971e3aac0SAndrea Arcangeli 107071e3aac0SAndrea Arcangeli ret = 0; 107171e3aac0SAndrea Arcangeli out_unlock: 1072c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 1073c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 107471e3aac0SAndrea Arcangeli out: 107571e3aac0SAndrea Arcangeli return ret; 107671e3aac0SAndrea Arcangeli } 107771e3aac0SAndrea Arcangeli 1078a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1079a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 1080a8f97366SKirill A. Shutemov pud_t *pud, int flags) 1081a00cc7d9SMatthew Wilcox { 1082a00cc7d9SMatthew Wilcox pud_t _pud; 1083a00cc7d9SMatthew Wilcox 1084a8f97366SKirill A. Shutemov _pud = pud_mkyoung(*pud); 1085a8f97366SKirill A. Shutemov if (flags & FOLL_WRITE) 1086a8f97366SKirill A. Shutemov _pud = pud_mkdirty(_pud); 1087a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 1088a8f97366SKirill A. Shutemov pud, _pud, flags & FOLL_WRITE)) 1089a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1090a00cc7d9SMatthew Wilcox } 1091a00cc7d9SMatthew Wilcox 1092a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 1093df06b37fSKeith Busch pud_t *pud, int flags, struct dev_pagemap **pgmap) 1094a00cc7d9SMatthew Wilcox { 1095a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 1096a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1097a00cc7d9SMatthew Wilcox struct page *page; 1098a00cc7d9SMatthew Wilcox 1099a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 1100a00cc7d9SMatthew Wilcox 1101f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pud_write(*pud)) 1102a00cc7d9SMatthew Wilcox return NULL; 1103a00cc7d9SMatthew Wilcox 1104a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 1105a00cc7d9SMatthew Wilcox /* pass */; 1106a00cc7d9SMatthew Wilcox else 1107a00cc7d9SMatthew Wilcox return NULL; 1108a00cc7d9SMatthew Wilcox 1109a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 1110a8f97366SKirill A. Shutemov touch_pud(vma, addr, pud, flags); 1111a00cc7d9SMatthew Wilcox 1112a00cc7d9SMatthew Wilcox /* 1113a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 1114a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 1115a00cc7d9SMatthew Wilcox */ 1116a00cc7d9SMatthew Wilcox if (!(flags & FOLL_GET)) 1117a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 1118a00cc7d9SMatthew Wilcox 1119a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 1120df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1121df06b37fSKeith Busch if (!*pgmap) 1122a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 1123a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 1124a00cc7d9SMatthew Wilcox get_page(page); 1125a00cc7d9SMatthew Wilcox 1126a00cc7d9SMatthew Wilcox return page; 1127a00cc7d9SMatthew Wilcox } 1128a00cc7d9SMatthew Wilcox 1129a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1130a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1131a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1132a00cc7d9SMatthew Wilcox { 1133a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1134a00cc7d9SMatthew Wilcox pud_t pud; 1135a00cc7d9SMatthew Wilcox int ret; 1136a00cc7d9SMatthew Wilcox 1137a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1138a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1139a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1140a00cc7d9SMatthew Wilcox 1141a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1142a00cc7d9SMatthew Wilcox pud = *src_pud; 1143a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1144a00cc7d9SMatthew Wilcox goto out_unlock; 1145a00cc7d9SMatthew Wilcox 1146a00cc7d9SMatthew Wilcox /* 1147a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1148a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1149a00cc7d9SMatthew Wilcox * a page table. 1150a00cc7d9SMatthew Wilcox */ 1151a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1152a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1153a00cc7d9SMatthew Wilcox } 1154a00cc7d9SMatthew Wilcox 1155a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1156a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1157a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1158a00cc7d9SMatthew Wilcox 1159a00cc7d9SMatthew Wilcox ret = 0; 1160a00cc7d9SMatthew Wilcox out_unlock: 1161a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1162a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1163a00cc7d9SMatthew Wilcox return ret; 1164a00cc7d9SMatthew Wilcox } 1165a00cc7d9SMatthew Wilcox 1166a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1167a00cc7d9SMatthew Wilcox { 1168a00cc7d9SMatthew Wilcox pud_t entry; 1169a00cc7d9SMatthew Wilcox unsigned long haddr; 1170a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1171a00cc7d9SMatthew Wilcox 1172a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1173a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1174a00cc7d9SMatthew Wilcox goto unlock; 1175a00cc7d9SMatthew Wilcox 1176a00cc7d9SMatthew Wilcox entry = pud_mkyoung(orig_pud); 1177a00cc7d9SMatthew Wilcox if (write) 1178a00cc7d9SMatthew Wilcox entry = pud_mkdirty(entry); 1179a00cc7d9SMatthew Wilcox haddr = vmf->address & HPAGE_PUD_MASK; 1180a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) 1181a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); 1182a00cc7d9SMatthew Wilcox 1183a00cc7d9SMatthew Wilcox unlock: 1184a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1185a00cc7d9SMatthew Wilcox } 1186a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1187a00cc7d9SMatthew Wilcox 118882b0f8c3SJan Kara void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) 1189a1dd450bSWill Deacon { 1190a1dd450bSWill Deacon pmd_t entry; 1191a1dd450bSWill Deacon unsigned long haddr; 119220f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1193a1dd450bSWill Deacon 119482b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 119582b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 1196a1dd450bSWill Deacon goto unlock; 1197a1dd450bSWill Deacon 1198a1dd450bSWill Deacon entry = pmd_mkyoung(orig_pmd); 119920f664aaSMinchan Kim if (write) 120020f664aaSMinchan Kim entry = pmd_mkdirty(entry); 120182b0f8c3SJan Kara haddr = vmf->address & HPAGE_PMD_MASK; 120220f664aaSMinchan Kim if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) 120382b0f8c3SJan Kara update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); 1204a1dd450bSWill Deacon 1205a1dd450bSWill Deacon unlock: 120682b0f8c3SJan Kara spin_unlock(vmf->ptl); 1207a1dd450bSWill Deacon } 1208a1dd450bSWill Deacon 12092b740303SSouptick Joarder static vm_fault_t do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, 12102b740303SSouptick Joarder pmd_t orig_pmd, struct page *page) 121171e3aac0SAndrea Arcangeli { 121282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 121382b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 121400501b53SJohannes Weiner struct mem_cgroup *memcg; 121571e3aac0SAndrea Arcangeli pgtable_t pgtable; 121671e3aac0SAndrea Arcangeli pmd_t _pmd; 12172b740303SSouptick Joarder int i; 12182b740303SSouptick Joarder vm_fault_t ret = 0; 121971e3aac0SAndrea Arcangeli struct page **pages; 1220ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 122171e3aac0SAndrea Arcangeli 12226da2ec56SKees Cook pages = kmalloc_array(HPAGE_PMD_NR, sizeof(struct page *), 122371e3aac0SAndrea Arcangeli GFP_KERNEL); 122471e3aac0SAndrea Arcangeli if (unlikely(!pages)) { 122571e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 122671e3aac0SAndrea Arcangeli goto out; 122771e3aac0SAndrea Arcangeli } 122871e3aac0SAndrea Arcangeli 122971e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 123041b6167eSMichal Hocko pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, 123182b0f8c3SJan Kara vmf->address, page_to_nid(page)); 1232b9bbfbe3SAndrea Arcangeli if (unlikely(!pages[i] || 12332cf85583STejun Heo mem_cgroup_try_charge_delay(pages[i], vma->vm_mm, 1234bae473a4SKirill A. Shutemov GFP_KERNEL, &memcg, false))) { 1235b9bbfbe3SAndrea Arcangeli if (pages[i]) 123671e3aac0SAndrea Arcangeli put_page(pages[i]); 1237b9bbfbe3SAndrea Arcangeli while (--i >= 0) { 123800501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 123900501b53SJohannes Weiner set_page_private(pages[i], 0); 1240f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(pages[i], memcg, 1241f627c2f5SKirill A. Shutemov false); 1242b9bbfbe3SAndrea Arcangeli put_page(pages[i]); 1243b9bbfbe3SAndrea Arcangeli } 124471e3aac0SAndrea Arcangeli kfree(pages); 124571e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 124671e3aac0SAndrea Arcangeli goto out; 124771e3aac0SAndrea Arcangeli } 124800501b53SJohannes Weiner set_page_private(pages[i], (unsigned long)memcg); 124971e3aac0SAndrea Arcangeli } 125071e3aac0SAndrea Arcangeli 125171e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 125271e3aac0SAndrea Arcangeli copy_user_highpage(pages[i], page + i, 12530089e485SHillf Danton haddr + PAGE_SIZE * i, vma); 125471e3aac0SAndrea Arcangeli __SetPageUptodate(pages[i]); 125571e3aac0SAndrea Arcangeli cond_resched(); 125671e3aac0SAndrea Arcangeli } 125771e3aac0SAndrea Arcangeli 12587269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 12597269f999SJérôme Glisse haddr, haddr + HPAGE_PMD_SIZE); 1260ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 12612ec74c3eSSagi Grimberg 126282b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 126382b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 126471e3aac0SAndrea Arcangeli goto out_free_pages; 1265309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 126671e3aac0SAndrea Arcangeli 12670f10851eSJérôme Glisse /* 12680f10851eSJérôme Glisse * Leave pmd empty until pte is filled note we must notify here as 12690f10851eSJérôme Glisse * concurrent CPU thread might write to new page before the call to 12700f10851eSJérôme Glisse * mmu_notifier_invalidate_range_end() happens which can lead to a 12710f10851eSJérôme Glisse * device seeing memory write in different order than CPU. 12720f10851eSJérôme Glisse * 1273ad56b738SMike Rapoport * See Documentation/vm/mmu_notifier.rst 12740f10851eSJérôme Glisse */ 127582b0f8c3SJan Kara pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); 127671e3aac0SAndrea Arcangeli 127782b0f8c3SJan Kara pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); 1278bae473a4SKirill A. Shutemov pmd_populate(vma->vm_mm, &_pmd, pgtable); 127971e3aac0SAndrea Arcangeli 128071e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 1281bae473a4SKirill A. Shutemov pte_t entry; 128271e3aac0SAndrea Arcangeli entry = mk_pte(pages[i], vma->vm_page_prot); 128371e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 128400501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 128500501b53SJohannes Weiner set_page_private(pages[i], 0); 128682b0f8c3SJan Kara page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); 1287f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(pages[i], memcg, false, false); 128800501b53SJohannes Weiner lru_cache_add_active_or_unevictable(pages[i], vma); 128982b0f8c3SJan Kara vmf->pte = pte_offset_map(&_pmd, haddr); 129082b0f8c3SJan Kara VM_BUG_ON(!pte_none(*vmf->pte)); 129182b0f8c3SJan Kara set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); 129282b0f8c3SJan Kara pte_unmap(vmf->pte); 129371e3aac0SAndrea Arcangeli } 129471e3aac0SAndrea Arcangeli kfree(pages); 129571e3aac0SAndrea Arcangeli 129671e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 129782b0f8c3SJan Kara pmd_populate(vma->vm_mm, vmf->pmd, pgtable); 1298d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 129982b0f8c3SJan Kara spin_unlock(vmf->ptl); 130071e3aac0SAndrea Arcangeli 13014645b9feSJérôme Glisse /* 13024645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 13034645b9feSJérôme Glisse * the above pmdp_huge_clear_flush_notify() did already call it. 13044645b9feSJérôme Glisse */ 1305ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 13062ec74c3eSSagi Grimberg 130771e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 130871e3aac0SAndrea Arcangeli put_page(page); 130971e3aac0SAndrea Arcangeli 131071e3aac0SAndrea Arcangeli out: 131171e3aac0SAndrea Arcangeli return ret; 131271e3aac0SAndrea Arcangeli 131371e3aac0SAndrea Arcangeli out_free_pages: 131482b0f8c3SJan Kara spin_unlock(vmf->ptl); 1315ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 1316b9bbfbe3SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 131700501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 131800501b53SJohannes Weiner set_page_private(pages[i], 0); 1319f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(pages[i], memcg, false); 132071e3aac0SAndrea Arcangeli put_page(pages[i]); 1321b9bbfbe3SAndrea Arcangeli } 132271e3aac0SAndrea Arcangeli kfree(pages); 132371e3aac0SAndrea Arcangeli goto out; 132471e3aac0SAndrea Arcangeli } 132571e3aac0SAndrea Arcangeli 13262b740303SSouptick Joarder vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) 132771e3aac0SAndrea Arcangeli { 132882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 132993b4796dSKirill A. Shutemov struct page *page = NULL, *new_page; 133000501b53SJohannes Weiner struct mem_cgroup *memcg; 133182b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 1332ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 13333b363692SMichal Hocko gfp_t huge_gfp; /* for allocation and charge */ 13342b740303SSouptick Joarder vm_fault_t ret = 0; 133571e3aac0SAndrea Arcangeli 133682b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 133781d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 133893b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 133993b4796dSKirill A. Shutemov goto alloc; 134082b0f8c3SJan Kara spin_lock(vmf->ptl); 134182b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 134271e3aac0SAndrea Arcangeli goto out_unlock; 134371e3aac0SAndrea Arcangeli 134471e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 1345309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); 13461f25fe20SKirill A. Shutemov /* 13471f25fe20SKirill A. Shutemov * We can only reuse the page if nobody else maps the huge page or it's 13486d0a07edSAndrea Arcangeli * part. 13491f25fe20SKirill A. Shutemov */ 1350ba3c4ce6SHuang Ying if (!trylock_page(page)) { 1351ba3c4ce6SHuang Ying get_page(page); 1352ba3c4ce6SHuang Ying spin_unlock(vmf->ptl); 1353ba3c4ce6SHuang Ying lock_page(page); 1354ba3c4ce6SHuang Ying spin_lock(vmf->ptl); 1355ba3c4ce6SHuang Ying if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 1356ba3c4ce6SHuang Ying unlock_page(page); 1357ba3c4ce6SHuang Ying put_page(page); 1358ba3c4ce6SHuang Ying goto out_unlock; 1359ba3c4ce6SHuang Ying } 1360ba3c4ce6SHuang Ying put_page(page); 1361ba3c4ce6SHuang Ying } 1362ba3c4ce6SHuang Ying if (reuse_swap_page(page, NULL)) { 136371e3aac0SAndrea Arcangeli pmd_t entry; 136471e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 1365f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 136682b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 136782b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 136871e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 1369ba3c4ce6SHuang Ying unlock_page(page); 137071e3aac0SAndrea Arcangeli goto out_unlock; 137171e3aac0SAndrea Arcangeli } 1372ba3c4ce6SHuang Ying unlock_page(page); 1373ddc58f27SKirill A. Shutemov get_page(page); 137482b0f8c3SJan Kara spin_unlock(vmf->ptl); 137593b4796dSKirill A. Shutemov alloc: 13767635d9cbSMichal Hocko if (__transparent_hugepage_enabled(vma) && 1377077fcf11SAneesh Kumar K.V !transparent_hugepage_debug_cow()) { 137819deb769SDavid Rientjes huge_gfp = alloc_hugepage_direct_gfpmask(vma); 137919deb769SDavid Rientjes new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); 1380077fcf11SAneesh Kumar K.V } else 138171e3aac0SAndrea Arcangeli new_page = NULL; 138271e3aac0SAndrea Arcangeli 13839a982250SKirill A. Shutemov if (likely(new_page)) { 13849a982250SKirill A. Shutemov prep_transhuge_page(new_page); 13859a982250SKirill A. Shutemov } else { 1386eecc1e42SHugh Dickins if (!page) { 138782b0f8c3SJan Kara split_huge_pmd(vma, vmf->pmd, vmf->address); 1388e9b71ca9SKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 138993b4796dSKirill A. Shutemov } else { 139082b0f8c3SJan Kara ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); 13919845cbbdSKirill A. Shutemov if (ret & VM_FAULT_OOM) { 139282b0f8c3SJan Kara split_huge_pmd(vma, vmf->pmd, vmf->address); 13939845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 13949845cbbdSKirill A. Shutemov } 1395ddc58f27SKirill A. Shutemov put_page(page); 139693b4796dSKirill A. Shutemov } 139717766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 139871e3aac0SAndrea Arcangeli goto out; 139971e3aac0SAndrea Arcangeli } 140071e3aac0SAndrea Arcangeli 14012cf85583STejun Heo if (unlikely(mem_cgroup_try_charge_delay(new_page, vma->vm_mm, 14022a70f6a7SMichal Hocko huge_gfp, &memcg, true))) { 1403b9bbfbe3SAndrea Arcangeli put_page(new_page); 140482b0f8c3SJan Kara split_huge_pmd(vma, vmf->pmd, vmf->address); 1405bae473a4SKirill A. Shutemov if (page) 1406ddc58f27SKirill A. Shutemov put_page(page); 14079845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 140817766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 1409b9bbfbe3SAndrea Arcangeli goto out; 1410b9bbfbe3SAndrea Arcangeli } 1411b9bbfbe3SAndrea Arcangeli 141217766ddeSDavid Rientjes count_vm_event(THP_FAULT_ALLOC); 14131ff9e6e1SChris Down count_memcg_events(memcg, THP_FAULT_ALLOC, 1); 141417766ddeSDavid Rientjes 1415eecc1e42SHugh Dickins if (!page) 1416c79b57e4SHuang Ying clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR); 141793b4796dSKirill A. Shutemov else 1418c9f4cd71SHuang Ying copy_user_huge_page(new_page, page, vmf->address, 1419c9f4cd71SHuang Ying vma, HPAGE_PMD_NR); 142071e3aac0SAndrea Arcangeli __SetPageUptodate(new_page); 142171e3aac0SAndrea Arcangeli 14227269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 14237269f999SJérôme Glisse haddr, haddr + HPAGE_PMD_SIZE); 1424ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 14252ec74c3eSSagi Grimberg 142682b0f8c3SJan Kara spin_lock(vmf->ptl); 142793b4796dSKirill A. Shutemov if (page) 1428ddc58f27SKirill A. Shutemov put_page(page); 142982b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 143082b0f8c3SJan Kara spin_unlock(vmf->ptl); 1431f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(new_page, memcg, true); 143271e3aac0SAndrea Arcangeli put_page(new_page); 14332ec74c3eSSagi Grimberg goto out_mn; 1434b9bbfbe3SAndrea Arcangeli } else { 143571e3aac0SAndrea Arcangeli pmd_t entry; 14363122359aSKirill A. Shutemov entry = mk_huge_pmd(new_page, vma->vm_page_prot); 1437f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 143882b0f8c3SJan Kara pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); 1439d281ee61SKirill A. Shutemov page_add_new_anon_rmap(new_page, vma, haddr, true); 1440f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(new_page, memcg, false, true); 144100501b53SJohannes Weiner lru_cache_add_active_or_unevictable(new_page, vma); 144282b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 144382b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1444eecc1e42SHugh Dickins if (!page) { 1445bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 144697ae1749SKirill A. Shutemov } else { 1447309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1448d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 144971e3aac0SAndrea Arcangeli put_page(page); 145093b4796dSKirill A. Shutemov } 145171e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 145271e3aac0SAndrea Arcangeli } 145382b0f8c3SJan Kara spin_unlock(vmf->ptl); 14542ec74c3eSSagi Grimberg out_mn: 14554645b9feSJérôme Glisse /* 14564645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 14574645b9feSJérôme Glisse * the above pmdp_huge_clear_flush_notify() did already call it. 14584645b9feSJérôme Glisse */ 1459ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 14602ec74c3eSSagi Grimberg out: 14612ec74c3eSSagi Grimberg return ret; 146271e3aac0SAndrea Arcangeli out_unlock: 146382b0f8c3SJan Kara spin_unlock(vmf->ptl); 146471e3aac0SAndrea Arcangeli return ret; 146571e3aac0SAndrea Arcangeli } 146671e3aac0SAndrea Arcangeli 14678310d48bSKeno Fischer /* 14688310d48bSKeno Fischer * FOLL_FORCE can write to even unwritable pmd's, but only 14698310d48bSKeno Fischer * after we've gone through a COW cycle and they are dirty. 14708310d48bSKeno Fischer */ 14718310d48bSKeno Fischer static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) 14728310d48bSKeno Fischer { 1473f6f37321SLinus Torvalds return pmd_write(pmd) || 14748310d48bSKeno Fischer ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); 14758310d48bSKeno Fischer } 14768310d48bSKeno Fischer 1477b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 147871e3aac0SAndrea Arcangeli unsigned long addr, 147971e3aac0SAndrea Arcangeli pmd_t *pmd, 148071e3aac0SAndrea Arcangeli unsigned int flags) 148171e3aac0SAndrea Arcangeli { 1482b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 148371e3aac0SAndrea Arcangeli struct page *page = NULL; 148471e3aac0SAndrea Arcangeli 1485c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 148671e3aac0SAndrea Arcangeli 14878310d48bSKeno Fischer if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) 148871e3aac0SAndrea Arcangeli goto out; 148971e3aac0SAndrea Arcangeli 149085facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 149185facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 149285facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 149385facf25SKirill A. Shutemov 14942b4847e7SMel Gorman /* Full NUMA hinting faults to serialise migration in fault paths */ 14958a0516edSMel Gorman if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) 14962b4847e7SMel Gorman goto out; 14972b4847e7SMel Gorman 149871e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 1499ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 15003565fce3SDan Williams if (flags & FOLL_TOUCH) 1501a8f97366SKirill A. Shutemov touch_pmd(vma, addr, pmd, flags); 1502de60f5f1SEric B Munson if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { 1503e90309c9SKirill A. Shutemov /* 1504e90309c9SKirill A. Shutemov * We don't mlock() pte-mapped THPs. This way we can avoid 1505e90309c9SKirill A. Shutemov * leaking mlocked pages into non-VM_LOCKED VMAs. 1506e90309c9SKirill A. Shutemov * 15079a73f61bSKirill A. Shutemov * For anon THP: 15089a73f61bSKirill A. Shutemov * 1509e90309c9SKirill A. Shutemov * In most cases the pmd is the only mapping of the page as we 1510e90309c9SKirill A. Shutemov * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for 1511e90309c9SKirill A. Shutemov * writable private mappings in populate_vma_page_range(). 1512e90309c9SKirill A. Shutemov * 1513e90309c9SKirill A. Shutemov * The only scenario when we have the page shared here is if we 1514e90309c9SKirill A. Shutemov * mlocking read-only mapping shared over fork(). We skip 1515e90309c9SKirill A. Shutemov * mlocking such pages. 15169a73f61bSKirill A. Shutemov * 15179a73f61bSKirill A. Shutemov * For file THP: 15189a73f61bSKirill A. Shutemov * 15199a73f61bSKirill A. Shutemov * We can expect PageDoubleMap() to be stable under page lock: 15209a73f61bSKirill A. Shutemov * for file pages we set it in page_add_file_rmap(), which 15219a73f61bSKirill A. Shutemov * requires page to be locked. 1522e90309c9SKirill A. Shutemov */ 15239a73f61bSKirill A. Shutemov 15249a73f61bSKirill A. Shutemov if (PageAnon(page) && compound_mapcount(page) != 1) 15259a73f61bSKirill A. Shutemov goto skip_mlock; 15269a73f61bSKirill A. Shutemov if (PageDoubleMap(page) || !page->mapping) 15279a73f61bSKirill A. Shutemov goto skip_mlock; 15289a73f61bSKirill A. Shutemov if (!trylock_page(page)) 15299a73f61bSKirill A. Shutemov goto skip_mlock; 1530b676b293SDavid Rientjes lru_add_drain(); 15319a73f61bSKirill A. Shutemov if (page->mapping && !PageDoubleMap(page)) 1532b676b293SDavid Rientjes mlock_vma_page(page); 1533b676b293SDavid Rientjes unlock_page(page); 1534b676b293SDavid Rientjes } 15359a73f61bSKirill A. Shutemov skip_mlock: 153671e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1537ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 153871e3aac0SAndrea Arcangeli if (flags & FOLL_GET) 1539ddc58f27SKirill A. Shutemov get_page(page); 154071e3aac0SAndrea Arcangeli 154171e3aac0SAndrea Arcangeli out: 154271e3aac0SAndrea Arcangeli return page; 154371e3aac0SAndrea Arcangeli } 154471e3aac0SAndrea Arcangeli 1545d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 15462b740303SSouptick Joarder vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) 1547d10e63f2SMel Gorman { 154882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1549b8916634SMel Gorman struct anon_vma *anon_vma = NULL; 1550b32967ffSMel Gorman struct page *page; 155182b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 155298fa15f3SAnshuman Khandual int page_nid = NUMA_NO_NODE, this_nid = numa_node_id(); 155390572890SPeter Zijlstra int target_nid, last_cpupid = -1; 15548191acbdSMel Gorman bool page_locked; 15558191acbdSMel Gorman bool migrated = false; 1556b191f9b1SMel Gorman bool was_writable; 15576688cc05SPeter Zijlstra int flags = 0; 1558d10e63f2SMel Gorman 155982b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 156082b0f8c3SJan Kara if (unlikely(!pmd_same(pmd, *vmf->pmd))) 1561d10e63f2SMel Gorman goto out_unlock; 1562d10e63f2SMel Gorman 1563de466bd6SMel Gorman /* 1564de466bd6SMel Gorman * If there are potential migrations, wait for completion and retry 1565de466bd6SMel Gorman * without disrupting NUMA hinting information. Do not relock and 1566de466bd6SMel Gorman * check_same as the page may no longer be mapped. 1567de466bd6SMel Gorman */ 156882b0f8c3SJan Kara if (unlikely(pmd_trans_migrating(*vmf->pmd))) { 156982b0f8c3SJan Kara page = pmd_page(*vmf->pmd); 15703c226c63SMark Rutland if (!get_page_unless_zero(page)) 15713c226c63SMark Rutland goto out_unlock; 157282b0f8c3SJan Kara spin_unlock(vmf->ptl); 15739a1ea439SHugh Dickins put_and_wait_on_page_locked(page); 1574de466bd6SMel Gorman goto out; 1575de466bd6SMel Gorman } 1576de466bd6SMel Gorman 1577d10e63f2SMel Gorman page = pmd_page(pmd); 1578a1a46184SMel Gorman BUG_ON(is_huge_zero_page(page)); 15798191acbdSMel Gorman page_nid = page_to_nid(page); 158090572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 158103c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 158204bb2f94SRik van Riel if (page_nid == this_nid) { 158303c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 158404bb2f94SRik van Riel flags |= TNF_FAULT_LOCAL; 158504bb2f94SRik van Riel } 15864daae3b4SMel Gorman 1587bea66fbdSMel Gorman /* See similar comment in do_numa_page for explanation */ 1588288bc549SAneesh Kumar K.V if (!pmd_savedwrite(pmd)) 15896688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 15906688cc05SPeter Zijlstra 15916688cc05SPeter Zijlstra /* 1592ff9042b1SMel Gorman * Acquire the page lock to serialise THP migrations but avoid dropping 1593ff9042b1SMel Gorman * page_table_lock if at all possible 1594ff9042b1SMel Gorman */ 1595b8916634SMel Gorman page_locked = trylock_page(page); 1596b8916634SMel Gorman target_nid = mpol_misplaced(page, vma, haddr); 159798fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 1598b8916634SMel Gorman /* If the page was locked, there are no parallel migrations */ 1599a54a407fSMel Gorman if (page_locked) 1600b8916634SMel Gorman goto clear_pmdnuma; 16012b4847e7SMel Gorman } 1602cbee9f88SPeter Zijlstra 1603de466bd6SMel Gorman /* Migration could have started since the pmd_trans_migrating check */ 16042b4847e7SMel Gorman if (!page_locked) { 160598fa15f3SAnshuman Khandual page_nid = NUMA_NO_NODE; 16063c226c63SMark Rutland if (!get_page_unless_zero(page)) 16073c226c63SMark Rutland goto out_unlock; 160882b0f8c3SJan Kara spin_unlock(vmf->ptl); 16099a1ea439SHugh Dickins put_and_wait_on_page_locked(page); 1610b8916634SMel Gorman goto out; 1611b8916634SMel Gorman } 1612b8916634SMel Gorman 16132b4847e7SMel Gorman /* 16142b4847e7SMel Gorman * Page is misplaced. Page lock serialises migrations. Acquire anon_vma 16152b4847e7SMel Gorman * to serialises splits 16162b4847e7SMel Gorman */ 1617b8916634SMel Gorman get_page(page); 161882b0f8c3SJan Kara spin_unlock(vmf->ptl); 1619b8916634SMel Gorman anon_vma = page_lock_anon_vma_read(page); 1620b32967ffSMel Gorman 1621c69307d5SPeter Zijlstra /* Confirm the PMD did not change while page_table_lock was released */ 162282b0f8c3SJan Kara spin_lock(vmf->ptl); 162382b0f8c3SJan Kara if (unlikely(!pmd_same(pmd, *vmf->pmd))) { 1624b32967ffSMel Gorman unlock_page(page); 1625b32967ffSMel Gorman put_page(page); 162698fa15f3SAnshuman Khandual page_nid = NUMA_NO_NODE; 1627b32967ffSMel Gorman goto out_unlock; 1628b32967ffSMel Gorman } 1629ff9042b1SMel Gorman 1630c3a489caSMel Gorman /* Bail if we fail to protect against THP splits for any reason */ 1631c3a489caSMel Gorman if (unlikely(!anon_vma)) { 1632c3a489caSMel Gorman put_page(page); 163398fa15f3SAnshuman Khandual page_nid = NUMA_NO_NODE; 1634c3a489caSMel Gorman goto clear_pmdnuma; 1635c3a489caSMel Gorman } 1636c3a489caSMel Gorman 1637a54a407fSMel Gorman /* 16388b1b436dSPeter Zijlstra * Since we took the NUMA fault, we must have observed the !accessible 16398b1b436dSPeter Zijlstra * bit. Make sure all other CPUs agree with that, to avoid them 16408b1b436dSPeter Zijlstra * modifying the page we're about to migrate. 16418b1b436dSPeter Zijlstra * 16428b1b436dSPeter Zijlstra * Must be done under PTL such that we'll observe the relevant 1643ccde85baSPeter Zijlstra * inc_tlb_flush_pending(). 1644ccde85baSPeter Zijlstra * 1645ccde85baSPeter Zijlstra * We are not sure a pending tlb flush here is for a huge page 1646ccde85baSPeter Zijlstra * mapping or not. Hence use the tlb range variant 16478b1b436dSPeter Zijlstra */ 16487066f0f9SAndrea Arcangeli if (mm_tlb_flush_pending(vma->vm_mm)) { 1649ccde85baSPeter Zijlstra flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); 16507066f0f9SAndrea Arcangeli /* 16517066f0f9SAndrea Arcangeli * change_huge_pmd() released the pmd lock before 16527066f0f9SAndrea Arcangeli * invalidating the secondary MMUs sharing the primary 16537066f0f9SAndrea Arcangeli * MMU pagetables (with ->invalidate_range()). The 16547066f0f9SAndrea Arcangeli * mmu_notifier_invalidate_range_end() (which 16557066f0f9SAndrea Arcangeli * internally calls ->invalidate_range()) in 16567066f0f9SAndrea Arcangeli * change_pmd_range() will run after us, so we can't 16577066f0f9SAndrea Arcangeli * rely on it here and we need an explicit invalidate. 16587066f0f9SAndrea Arcangeli */ 16597066f0f9SAndrea Arcangeli mmu_notifier_invalidate_range(vma->vm_mm, haddr, 16607066f0f9SAndrea Arcangeli haddr + HPAGE_PMD_SIZE); 16617066f0f9SAndrea Arcangeli } 16628b1b436dSPeter Zijlstra 16638b1b436dSPeter Zijlstra /* 1664a54a407fSMel Gorman * Migrate the THP to the requested node, returns with page unlocked 16658a0516edSMel Gorman * and access rights restored. 1666a54a407fSMel Gorman */ 166782b0f8c3SJan Kara spin_unlock(vmf->ptl); 16688b1b436dSPeter Zijlstra 1669bae473a4SKirill A. Shutemov migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, 167082b0f8c3SJan Kara vmf->pmd, pmd, vmf->address, page, target_nid); 16716688cc05SPeter Zijlstra if (migrated) { 16726688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 16738191acbdSMel Gorman page_nid = target_nid; 1674074c2381SMel Gorman } else 1675074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1676b32967ffSMel Gorman 16778191acbdSMel Gorman goto out; 16784daae3b4SMel Gorman clear_pmdnuma: 1679a54a407fSMel Gorman BUG_ON(!PageLocked(page)); 1680288bc549SAneesh Kumar K.V was_writable = pmd_savedwrite(pmd); 16814d942466SMel Gorman pmd = pmd_modify(pmd, vma->vm_page_prot); 1682b7b04004SMel Gorman pmd = pmd_mkyoung(pmd); 1683b191f9b1SMel Gorman if (was_writable) 1684b191f9b1SMel Gorman pmd = pmd_mkwrite(pmd); 168582b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 168682b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1687a54a407fSMel Gorman unlock_page(page); 1688d10e63f2SMel Gorman out_unlock: 168982b0f8c3SJan Kara spin_unlock(vmf->ptl); 1690b8916634SMel Gorman 1691b8916634SMel Gorman out: 1692b8916634SMel Gorman if (anon_vma) 1693b8916634SMel Gorman page_unlock_anon_vma_read(anon_vma); 1694b8916634SMel Gorman 169598fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 169682b0f8c3SJan Kara task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, 16979a8b300fSAneesh Kumar K.V flags); 16988191acbdSMel Gorman 1699d10e63f2SMel Gorman return 0; 1700d10e63f2SMel Gorman } 1701d10e63f2SMel Gorman 1702319904adSHuang Ying /* 1703319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1704319904adSHuang Ying * Otherwise, return false. 1705319904adSHuang Ying */ 1706319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1707b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1708b8d3c4c3SMinchan Kim { 1709b8d3c4c3SMinchan Kim spinlock_t *ptl; 1710b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1711b8d3c4c3SMinchan Kim struct page *page; 1712b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1713319904adSHuang Ying bool ret = false; 1714b8d3c4c3SMinchan Kim 1715ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 171607e32661SAneesh Kumar K.V 1717b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1718b6ec57f4SKirill A. Shutemov if (!ptl) 171925eedabeSLinus Torvalds goto out_unlocked; 1720b8d3c4c3SMinchan Kim 1721b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1722319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1723b8d3c4c3SMinchan Kim goto out; 1724b8d3c4c3SMinchan Kim 172584c3fc4eSZi Yan if (unlikely(!pmd_present(orig_pmd))) { 172684c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 172784c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 172884c3fc4eSZi Yan goto out; 172984c3fc4eSZi Yan } 173084c3fc4eSZi Yan 1731b8d3c4c3SMinchan Kim page = pmd_page(orig_pmd); 1732b8d3c4c3SMinchan Kim /* 1733b8d3c4c3SMinchan Kim * If other processes are mapping this page, we couldn't discard 1734b8d3c4c3SMinchan Kim * the page unless they all do MADV_FREE so let's skip the page. 1735b8d3c4c3SMinchan Kim */ 1736b8d3c4c3SMinchan Kim if (page_mapcount(page) != 1) 1737b8d3c4c3SMinchan Kim goto out; 1738b8d3c4c3SMinchan Kim 1739b8d3c4c3SMinchan Kim if (!trylock_page(page)) 1740b8d3c4c3SMinchan Kim goto out; 1741b8d3c4c3SMinchan Kim 1742b8d3c4c3SMinchan Kim /* 1743b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1744b8d3c4c3SMinchan Kim * will deactivate only them. 1745b8d3c4c3SMinchan Kim */ 1746b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1747b8d3c4c3SMinchan Kim get_page(page); 1748b8d3c4c3SMinchan Kim spin_unlock(ptl); 17499818b8cdSHuang Ying split_huge_page(page); 1750b8d3c4c3SMinchan Kim unlock_page(page); 1751bbf29ffcSKirill A. Shutemov put_page(page); 1752b8d3c4c3SMinchan Kim goto out_unlocked; 1753b8d3c4c3SMinchan Kim } 1754b8d3c4c3SMinchan Kim 1755b8d3c4c3SMinchan Kim if (PageDirty(page)) 1756b8d3c4c3SMinchan Kim ClearPageDirty(page); 1757b8d3c4c3SMinchan Kim unlock_page(page); 1758b8d3c4c3SMinchan Kim 1759b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 176058ceeb6bSKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1761b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1762b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1763b8d3c4c3SMinchan Kim 1764b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1765b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1766b8d3c4c3SMinchan Kim } 1767802a3a92SShaohua Li 1768802a3a92SShaohua Li mark_page_lazyfree(page); 1769319904adSHuang Ying ret = true; 1770b8d3c4c3SMinchan Kim out: 1771b8d3c4c3SMinchan Kim spin_unlock(ptl); 1772b8d3c4c3SMinchan Kim out_unlocked: 1773b8d3c4c3SMinchan Kim return ret; 1774b8d3c4c3SMinchan Kim } 1775b8d3c4c3SMinchan Kim 1776953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1777953c66c2SAneesh Kumar K.V { 1778953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1779953c66c2SAneesh Kumar K.V 1780953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1781953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1782c4812909SKirill A. Shutemov mm_dec_nr_ptes(mm); 1783953c66c2SAneesh Kumar K.V } 1784953c66c2SAneesh Kumar K.V 178571e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1786f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 178771e3aac0SAndrea Arcangeli { 1788f5c8ad47SDavid Miller pmd_t orig_pmd; 1789da146769SKirill A. Shutemov spinlock_t *ptl; 1790da146769SKirill A. Shutemov 1791ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 179207e32661SAneesh Kumar K.V 1793b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1794b6ec57f4SKirill A. Shutemov if (!ptl) 1795da146769SKirill A. Shutemov return 0; 1796a6bf2bb0SAneesh Kumar K.V /* 1797a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 17988809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1799a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1800a6bf2bb0SAneesh Kumar K.V * operations. 1801a6bf2bb0SAneesh Kumar K.V */ 18028809aa2dSAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, 1803fcbe08d6SMartin Schwidefsky tlb->fullmm); 1804f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 18054897c765SMatthew Wilcox if (vma_is_dax(vma)) { 18063b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) 18073b6521f5SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 18084897c765SMatthew Wilcox spin_unlock(ptl); 1809da146769SKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 1810c0f2e176SAneesh Kumar K.V tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); 1811da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1812c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1813bf929152SKirill A. Shutemov spin_unlock(ptl); 1814c0f2e176SAneesh Kumar K.V tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); 1815479f0abbSKirill A. Shutemov } else { 1816616b8371SZi Yan struct page *page = NULL; 1817616b8371SZi Yan int flush_needed = 1; 1818616b8371SZi Yan 1819616b8371SZi Yan if (pmd_present(orig_pmd)) { 1820616b8371SZi Yan page = pmd_page(orig_pmd); 1821d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 1822309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1823309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1824616b8371SZi Yan } else if (thp_migration_supported()) { 1825616b8371SZi Yan swp_entry_t entry; 1826616b8371SZi Yan 1827616b8371SZi Yan VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); 1828616b8371SZi Yan entry = pmd_to_swp_entry(orig_pmd); 1829616b8371SZi Yan page = pfn_to_page(swp_offset(entry)); 1830616b8371SZi Yan flush_needed = 0; 1831616b8371SZi Yan } else 1832616b8371SZi Yan WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); 1833616b8371SZi Yan 1834b5072380SKirill A. Shutemov if (PageAnon(page)) { 1835c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1836b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1837b5072380SKirill A. Shutemov } else { 1838953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1839953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1840fadae295SYang Shi add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); 1841b5072380SKirill A. Shutemov } 1842616b8371SZi Yan 1843bf929152SKirill A. Shutemov spin_unlock(ptl); 1844616b8371SZi Yan if (flush_needed) 1845e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1846479f0abbSKirill A. Shutemov } 1847da146769SKirill A. Shutemov return 1; 184871e3aac0SAndrea Arcangeli } 184971e3aac0SAndrea Arcangeli 18501dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 18511dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 18521dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 18531dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 18541dd38b6cSAneesh Kumar K.V { 18551dd38b6cSAneesh Kumar K.V /* 18561dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 18571dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 18581dd38b6cSAneesh Kumar K.V * 18591dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 18601dd38b6cSAneesh Kumar K.V */ 18611dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 18621dd38b6cSAneesh Kumar K.V } 18631dd38b6cSAneesh Kumar K.V #endif 18641dd38b6cSAneesh Kumar K.V 1865ab6e3d09SNaoya Horiguchi static pmd_t move_soft_dirty_pmd(pmd_t pmd) 1866ab6e3d09SNaoya Horiguchi { 1867ab6e3d09SNaoya Horiguchi #ifdef CONFIG_MEM_SOFT_DIRTY 1868ab6e3d09SNaoya Horiguchi if (unlikely(is_pmd_migration_entry(pmd))) 1869ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 1870ab6e3d09SNaoya Horiguchi else if (pmd_present(pmd)) 1871ab6e3d09SNaoya Horiguchi pmd = pmd_mksoft_dirty(pmd); 1872ab6e3d09SNaoya Horiguchi #endif 1873ab6e3d09SNaoya Horiguchi return pmd; 1874ab6e3d09SNaoya Horiguchi } 1875ab6e3d09SNaoya Horiguchi 1876bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 187737a1c49aSAndrea Arcangeli unsigned long new_addr, unsigned long old_end, 1878eb66ae03SLinus Torvalds pmd_t *old_pmd, pmd_t *new_pmd) 187937a1c49aSAndrea Arcangeli { 1880bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 188137a1c49aSAndrea Arcangeli pmd_t pmd; 188237a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 18835d190420SAaron Lu bool force_flush = false; 188437a1c49aSAndrea Arcangeli 188537a1c49aSAndrea Arcangeli if ((old_addr & ~HPAGE_PMD_MASK) || 188637a1c49aSAndrea Arcangeli (new_addr & ~HPAGE_PMD_MASK) || 1887bf8616d5SHugh Dickins old_end - old_addr < HPAGE_PMD_SIZE) 18884b471e88SKirill A. Shutemov return false; 188937a1c49aSAndrea Arcangeli 189037a1c49aSAndrea Arcangeli /* 189137a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 189237a1c49aSAndrea Arcangeli * should have release it. 189337a1c49aSAndrea Arcangeli */ 189437a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 189537a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 18964b471e88SKirill A. Shutemov return false; 189737a1c49aSAndrea Arcangeli } 189837a1c49aSAndrea Arcangeli 1899bf929152SKirill A. Shutemov /* 1900bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1901bf929152SKirill A. Shutemov * ptlocks because exclusive mmap_sem prevents deadlock. 1902bf929152SKirill A. Shutemov */ 1903b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1904b6ec57f4SKirill A. Shutemov if (old_ptl) { 1905bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1906bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1907bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 19088809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1909eb66ae03SLinus Torvalds if (pmd_present(pmd)) 1910a2ce2666SAaron Lu force_flush = true; 191137a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 19123592806cSKirill A. Shutemov 19131dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1914b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 19153592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 19163592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 19173592806cSKirill A. Shutemov } 1918ab6e3d09SNaoya Horiguchi pmd = move_soft_dirty_pmd(pmd); 1919ab6e3d09SNaoya Horiguchi set_pmd_at(mm, new_addr, new_pmd, pmd); 19205d190420SAaron Lu if (force_flush) 19215d190420SAaron Lu flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 1922eb66ae03SLinus Torvalds if (new_ptl != old_ptl) 1923eb66ae03SLinus Torvalds spin_unlock(new_ptl); 1924bf929152SKirill A. Shutemov spin_unlock(old_ptl); 19254b471e88SKirill A. Shutemov return true; 192637a1c49aSAndrea Arcangeli } 19274b471e88SKirill A. Shutemov return false; 192837a1c49aSAndrea Arcangeli } 192937a1c49aSAndrea Arcangeli 1930f123d74aSMel Gorman /* 1931f123d74aSMel Gorman * Returns 1932f123d74aSMel Gorman * - 0 if PMD could not be locked 1933f123d74aSMel Gorman * - 1 if PMD was locked but protections unchange and TLB flush unnecessary 1934f123d74aSMel Gorman * - HPAGE_PMD_NR is protections changed and TLB flush necessary 1935f123d74aSMel Gorman */ 1936cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 1937e944fd67SMel Gorman unsigned long addr, pgprot_t newprot, int prot_numa) 1938cd7548abSJohannes Weiner { 1939cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1940bf929152SKirill A. Shutemov spinlock_t *ptl; 19410a85e51dSKirill A. Shutemov pmd_t entry; 19420a85e51dSKirill A. Shutemov bool preserve_write; 19430a85e51dSKirill A. Shutemov int ret; 1944cd7548abSJohannes Weiner 1945b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 19460a85e51dSKirill A. Shutemov if (!ptl) 19470a85e51dSKirill A. Shutemov return 0; 19480a85e51dSKirill A. Shutemov 19490a85e51dSKirill A. Shutemov preserve_write = prot_numa && pmd_write(*pmd); 1950ba68bc01SMel Gorman ret = 1; 1951e944fd67SMel Gorman 195284c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 195384c3fc4eSZi Yan if (is_swap_pmd(*pmd)) { 195484c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(*pmd); 195584c3fc4eSZi Yan 195684c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd)); 195784c3fc4eSZi Yan if (is_write_migration_entry(entry)) { 195884c3fc4eSZi Yan pmd_t newpmd; 195984c3fc4eSZi Yan /* 196084c3fc4eSZi Yan * A protection check is difficult so 196184c3fc4eSZi Yan * just be safe and disable write 196284c3fc4eSZi Yan */ 196384c3fc4eSZi Yan make_migration_entry_read(&entry); 196484c3fc4eSZi Yan newpmd = swp_entry_to_pmd(entry); 1965ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pmd)) 1966ab6e3d09SNaoya Horiguchi newpmd = pmd_swp_mksoft_dirty(newpmd); 196784c3fc4eSZi Yan set_pmd_at(mm, addr, pmd, newpmd); 196884c3fc4eSZi Yan } 196984c3fc4eSZi Yan goto unlock; 197084c3fc4eSZi Yan } 197184c3fc4eSZi Yan #endif 197284c3fc4eSZi Yan 1973e944fd67SMel Gorman /* 1974e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1975e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1976e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1977e944fd67SMel Gorman */ 19780a85e51dSKirill A. Shutemov if (prot_numa && is_huge_zero_pmd(*pmd)) 19790a85e51dSKirill A. Shutemov goto unlock; 1980e944fd67SMel Gorman 19810a85e51dSKirill A. Shutemov if (prot_numa && pmd_protnone(*pmd)) 19820a85e51dSKirill A. Shutemov goto unlock; 19830a85e51dSKirill A. Shutemov 1984ced10803SKirill A. Shutemov /* 1985ced10803SKirill A. Shutemov * In case prot_numa, we are under down_read(mmap_sem). It's critical 1986ced10803SKirill A. Shutemov * to not clear pmd intermittently to avoid race with MADV_DONTNEED 1987ced10803SKirill A. Shutemov * which is also under down_read(mmap_sem): 1988ced10803SKirill A. Shutemov * 1989ced10803SKirill A. Shutemov * CPU0: CPU1: 1990ced10803SKirill A. Shutemov * change_huge_pmd(prot_numa=1) 1991ced10803SKirill A. Shutemov * pmdp_huge_get_and_clear_notify() 1992ced10803SKirill A. Shutemov * madvise_dontneed() 1993ced10803SKirill A. Shutemov * zap_pmd_range() 1994ced10803SKirill A. Shutemov * pmd_trans_huge(*pmd) == 0 (without ptl) 1995ced10803SKirill A. Shutemov * // skip the pmd 1996ced10803SKirill A. Shutemov * set_pmd_at(); 1997ced10803SKirill A. Shutemov * // pmd is re-established 1998ced10803SKirill A. Shutemov * 1999ced10803SKirill A. Shutemov * The race makes MADV_DONTNEED miss the huge pmd and don't clear it 2000ced10803SKirill A. Shutemov * which may break userspace. 2001ced10803SKirill A. Shutemov * 2002ced10803SKirill A. Shutemov * pmdp_invalidate() is required to make sure we don't miss 2003ced10803SKirill A. Shutemov * dirty/young flags set by hardware. 2004ced10803SKirill A. Shutemov */ 2005a3cf988fSKirill A. Shutemov entry = pmdp_invalidate(vma, addr, pmd); 2006ced10803SKirill A. Shutemov 2007cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 2008b191f9b1SMel Gorman if (preserve_write) 2009288bc549SAneesh Kumar K.V entry = pmd_mk_savedwrite(entry); 2010f123d74aSMel Gorman ret = HPAGE_PMD_NR; 201156eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 20120a85e51dSKirill A. Shutemov BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); 20130a85e51dSKirill A. Shutemov unlock: 2014bf929152SKirill A. Shutemov spin_unlock(ptl); 2015cd7548abSJohannes Weiner return ret; 2016cd7548abSJohannes Weiner } 2017cd7548abSJohannes Weiner 2018025c5b24SNaoya Horiguchi /* 20198f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 2020025c5b24SNaoya Horiguchi * 20218f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 20228f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 2023025c5b24SNaoya Horiguchi */ 2024b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 2025025c5b24SNaoya Horiguchi { 2026b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 2027b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 202884c3fc4eSZi Yan if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || 202984c3fc4eSZi Yan pmd_devmap(*pmd))) 2030b6ec57f4SKirill A. Shutemov return ptl; 2031b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 2032b6ec57f4SKirill A. Shutemov return NULL; 2033025c5b24SNaoya Horiguchi } 2034025c5b24SNaoya Horiguchi 2035a00cc7d9SMatthew Wilcox /* 2036a00cc7d9SMatthew Wilcox * Returns true if a given pud maps a thp, false otherwise. 2037a00cc7d9SMatthew Wilcox * 2038a00cc7d9SMatthew Wilcox * Note that if it returns true, this routine returns without unlocking page 2039a00cc7d9SMatthew Wilcox * table lock. So callers must unlock it. 2040a00cc7d9SMatthew Wilcox */ 2041a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 2042a00cc7d9SMatthew Wilcox { 2043a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2044a00cc7d9SMatthew Wilcox 2045a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 2046a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 2047a00cc7d9SMatthew Wilcox return ptl; 2048a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2049a00cc7d9SMatthew Wilcox return NULL; 2050a00cc7d9SMatthew Wilcox } 2051a00cc7d9SMatthew Wilcox 2052a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 2053a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 2054a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 2055a00cc7d9SMatthew Wilcox { 2056a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2057a00cc7d9SMatthew Wilcox 2058a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 2059a00cc7d9SMatthew Wilcox if (!ptl) 2060a00cc7d9SMatthew Wilcox return 0; 2061a00cc7d9SMatthew Wilcox /* 2062a00cc7d9SMatthew Wilcox * For architectures like ppc64 we look at deposited pgtable 2063a00cc7d9SMatthew Wilcox * when calling pudp_huge_get_and_clear. So do the 2064a00cc7d9SMatthew Wilcox * pgtable_trans_huge_withdraw after finishing pudp related 2065a00cc7d9SMatthew Wilcox * operations. 2066a00cc7d9SMatthew Wilcox */ 206770516b93SQian Cai pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); 2068a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 2069a00cc7d9SMatthew Wilcox if (vma_is_dax(vma)) { 2070a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2071a00cc7d9SMatthew Wilcox /* No zero page support yet */ 2072a00cc7d9SMatthew Wilcox } else { 2073a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 2074a00cc7d9SMatthew Wilcox BUG(); 2075a00cc7d9SMatthew Wilcox } 2076a00cc7d9SMatthew Wilcox return 1; 2077a00cc7d9SMatthew Wilcox } 2078a00cc7d9SMatthew Wilcox 2079a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 2080a00cc7d9SMatthew Wilcox unsigned long haddr) 2081a00cc7d9SMatthew Wilcox { 2082a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 2083a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2084a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 2085a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 2086a00cc7d9SMatthew Wilcox 2087ce9311cfSYisheng Xie count_vm_event(THP_SPLIT_PUD); 2088a00cc7d9SMatthew Wilcox 2089a00cc7d9SMatthew Wilcox pudp_huge_clear_flush_notify(vma, haddr, pud); 2090a00cc7d9SMatthew Wilcox } 2091a00cc7d9SMatthew Wilcox 2092a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 2093a00cc7d9SMatthew Wilcox unsigned long address) 2094a00cc7d9SMatthew Wilcox { 2095a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2096ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2097a00cc7d9SMatthew Wilcox 20987269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 20996f4f13e8SJérôme Glisse address & HPAGE_PUD_MASK, 2100ac46d4f3SJérôme Glisse (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); 2101ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2102ac46d4f3SJérôme Glisse ptl = pud_lock(vma->vm_mm, pud); 2103a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 2104a00cc7d9SMatthew Wilcox goto out; 2105ac46d4f3SJérôme Glisse __split_huge_pud_locked(vma, pud, range.start); 2106a00cc7d9SMatthew Wilcox 2107a00cc7d9SMatthew Wilcox out: 2108a00cc7d9SMatthew Wilcox spin_unlock(ptl); 21094645b9feSJérôme Glisse /* 21104645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 21114645b9feSJérôme Glisse * the above pudp_huge_clear_flush_notify() did already call it. 21124645b9feSJérôme Glisse */ 2113ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 2114a00cc7d9SMatthew Wilcox } 2115a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 2116a00cc7d9SMatthew Wilcox 2117eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2118eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2119eef1b3baSKirill A. Shutemov { 2120eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2121eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2122eef1b3baSKirill A. Shutemov pmd_t _pmd; 2123eef1b3baSKirill A. Shutemov int i; 2124eef1b3baSKirill A. Shutemov 21250f10851eSJérôme Glisse /* 21260f10851eSJérôme Glisse * Leave pmd empty until pte is filled note that it is fine to delay 21270f10851eSJérôme Glisse * notification until mmu_notifier_invalidate_range_end() as we are 21280f10851eSJérôme Glisse * replacing a zero pmd write protected page with a zero pte write 21290f10851eSJérôme Glisse * protected page. 21300f10851eSJérôme Glisse * 2131ad56b738SMike Rapoport * See Documentation/vm/mmu_notifier.rst 21320f10851eSJérôme Glisse */ 21330f10851eSJérôme Glisse pmdp_huge_clear_flush(vma, haddr, pmd); 2134eef1b3baSKirill A. Shutemov 2135eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2136eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2137eef1b3baSKirill A. Shutemov 2138eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 2139eef1b3baSKirill A. Shutemov pte_t *pte, entry; 2140eef1b3baSKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 2141eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 2142eef1b3baSKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 2143eef1b3baSKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 2144eef1b3baSKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 2145eef1b3baSKirill A. Shutemov pte_unmap(pte); 2146eef1b3baSKirill A. Shutemov } 2147eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2148eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2149eef1b3baSKirill A. Shutemov } 2150eef1b3baSKirill A. Shutemov 2151eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 2152ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 2153eef1b3baSKirill A. Shutemov { 2154eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2155eef1b3baSKirill A. Shutemov struct page *page; 2156eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2157423ac9afSAneesh Kumar K.V pmd_t old_pmd, _pmd; 2158a3cf988fSKirill A. Shutemov bool young, write, soft_dirty, pmd_migration = false; 21592ac015e2SKirill A. Shutemov unsigned long addr; 2160eef1b3baSKirill A. Shutemov int i; 2161eef1b3baSKirill A. Shutemov 2162eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 2163eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2164eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 216584c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) 216684c3fc4eSZi Yan && !pmd_devmap(*pmd)); 2167eef1b3baSKirill A. Shutemov 2168eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 2169eef1b3baSKirill A. Shutemov 2170d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 2171d21b9e57SKirill A. Shutemov _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); 2172953c66c2SAneesh Kumar K.V /* 2173953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 2174953c66c2SAneesh Kumar K.V * just go ahead and zap it 2175953c66c2SAneesh Kumar K.V */ 2176953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 2177953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 2178d21b9e57SKirill A. Shutemov if (vma_is_dax(vma)) 2179d21b9e57SKirill A. Shutemov return; 2180d21b9e57SKirill A. Shutemov page = pmd_page(_pmd); 2181e1f1b157SHugh Dickins if (!PageDirty(page) && pmd_dirty(_pmd)) 2182e1f1b157SHugh Dickins set_page_dirty(page); 2183d21b9e57SKirill A. Shutemov if (!PageReferenced(page) && pmd_young(_pmd)) 2184d21b9e57SKirill A. Shutemov SetPageReferenced(page); 2185d21b9e57SKirill A. Shutemov page_remove_rmap(page, true); 2186d21b9e57SKirill A. Shutemov put_page(page); 2187fadae295SYang Shi add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); 2188eef1b3baSKirill A. Shutemov return; 2189eef1b3baSKirill A. Shutemov } else if (is_huge_zero_pmd(*pmd)) { 21904645b9feSJérôme Glisse /* 21914645b9feSJérôme Glisse * FIXME: Do we want to invalidate secondary mmu by calling 21924645b9feSJérôme Glisse * mmu_notifier_invalidate_range() see comments below inside 21934645b9feSJérôme Glisse * __split_huge_pmd() ? 21944645b9feSJérôme Glisse * 21954645b9feSJérôme Glisse * We are going from a zero huge page write protected to zero 21964645b9feSJérôme Glisse * small page also write protected so it does not seems useful 21974645b9feSJérôme Glisse * to invalidate secondary mmu at this time. 21984645b9feSJérôme Glisse */ 2199eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 2200eef1b3baSKirill A. Shutemov } 2201eef1b3baSKirill A. Shutemov 2202423ac9afSAneesh Kumar K.V /* 2203423ac9afSAneesh Kumar K.V * Up to this point the pmd is present and huge and userland has the 2204423ac9afSAneesh Kumar K.V * whole access to the hugepage during the split (which happens in 2205423ac9afSAneesh Kumar K.V * place). If we overwrite the pmd with the not-huge version pointing 2206423ac9afSAneesh Kumar K.V * to the pte here (which of course we could if all CPUs were bug 2207423ac9afSAneesh Kumar K.V * free), userland could trigger a small page size TLB miss on the 2208423ac9afSAneesh Kumar K.V * small sized TLB while the hugepage TLB entry is still established in 2209423ac9afSAneesh Kumar K.V * the huge TLB. Some CPU doesn't like that. 2210423ac9afSAneesh Kumar K.V * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum 2211423ac9afSAneesh Kumar K.V * 383 on page 93. Intel should be safe but is also warns that it's 2212423ac9afSAneesh Kumar K.V * only safe if the permission and cache attributes of the two entries 2213423ac9afSAneesh Kumar K.V * loaded in the two TLB is identical (which should be the case here). 2214423ac9afSAneesh Kumar K.V * But it is generally safer to never allow small and huge TLB entries 2215423ac9afSAneesh Kumar K.V * for the same virtual address to be loaded simultaneously. So instead 2216423ac9afSAneesh Kumar K.V * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2217423ac9afSAneesh Kumar K.V * current pmd notpresent (atomically because here the pmd_trans_huge 2218423ac9afSAneesh Kumar K.V * must remain set at all times on the pmd until the split is complete 2219423ac9afSAneesh Kumar K.V * for this pmd), then we flush the SMP TLB and finally we write the 2220423ac9afSAneesh Kumar K.V * non-huge version of the pmd entry with pmd_populate. 2221423ac9afSAneesh Kumar K.V */ 2222423ac9afSAneesh Kumar K.V old_pmd = pmdp_invalidate(vma, haddr, pmd); 2223423ac9afSAneesh Kumar K.V 2224423ac9afSAneesh Kumar K.V pmd_migration = is_pmd_migration_entry(old_pmd); 22252e83ee1dSPeter Xu if (unlikely(pmd_migration)) { 222684c3fc4eSZi Yan swp_entry_t entry; 222784c3fc4eSZi Yan 2228423ac9afSAneesh Kumar K.V entry = pmd_to_swp_entry(old_pmd); 222984c3fc4eSZi Yan page = pfn_to_page(swp_offset(entry)); 22302e83ee1dSPeter Xu write = is_write_migration_entry(entry); 22312e83ee1dSPeter Xu young = false; 22322e83ee1dSPeter Xu soft_dirty = pmd_swp_soft_dirty(old_pmd); 22332e83ee1dSPeter Xu } else { 2234423ac9afSAneesh Kumar K.V page = pmd_page(old_pmd); 2235423ac9afSAneesh Kumar K.V if (pmd_dirty(old_pmd)) 2236423ac9afSAneesh Kumar K.V SetPageDirty(page); 2237423ac9afSAneesh Kumar K.V write = pmd_write(old_pmd); 2238423ac9afSAneesh Kumar K.V young = pmd_young(old_pmd); 2239423ac9afSAneesh Kumar K.V soft_dirty = pmd_soft_dirty(old_pmd); 22402e83ee1dSPeter Xu } 22412e83ee1dSPeter Xu VM_BUG_ON_PAGE(!page_count(page), page); 22422e83ee1dSPeter Xu page_ref_add(page, HPAGE_PMD_NR - 1); 2243eef1b3baSKirill A. Shutemov 2244423ac9afSAneesh Kumar K.V /* 2245423ac9afSAneesh Kumar K.V * Withdraw the table only after we mark the pmd entry invalid. 2246423ac9afSAneesh Kumar K.V * This's critical for some architectures (Power). 2247423ac9afSAneesh Kumar K.V */ 2248eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2249eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2250eef1b3baSKirill A. Shutemov 22512ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2252eef1b3baSKirill A. Shutemov pte_t entry, *pte; 2253eef1b3baSKirill A. Shutemov /* 2254eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 2255eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 2256eef1b3baSKirill A. Shutemov * permissions across VMAs. 2257eef1b3baSKirill A. Shutemov */ 225884c3fc4eSZi Yan if (freeze || pmd_migration) { 2259ba988280SKirill A. Shutemov swp_entry_t swp_entry; 2260ba988280SKirill A. Shutemov swp_entry = make_migration_entry(page + i, write); 2261ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 2262804dd150SAndrea Arcangeli if (soft_dirty) 2263804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 2264ba988280SKirill A. Shutemov } else { 22656d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 2266b8d3c4c3SMinchan Kim entry = maybe_mkwrite(entry, vma); 2267eef1b3baSKirill A. Shutemov if (!write) 2268eef1b3baSKirill A. Shutemov entry = pte_wrprotect(entry); 2269eef1b3baSKirill A. Shutemov if (!young) 2270eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 2271804dd150SAndrea Arcangeli if (soft_dirty) 2272804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 2273ba988280SKirill A. Shutemov } 22742ac015e2SKirill A. Shutemov pte = pte_offset_map(&_pmd, addr); 2275eef1b3baSKirill A. Shutemov BUG_ON(!pte_none(*pte)); 22762ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 2277eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 2278eef1b3baSKirill A. Shutemov pte_unmap(pte); 2279eef1b3baSKirill A. Shutemov } 2280eef1b3baSKirill A. Shutemov 2281eef1b3baSKirill A. Shutemov /* 2282eef1b3baSKirill A. Shutemov * Set PG_double_map before dropping compound_mapcount to avoid 2283eef1b3baSKirill A. Shutemov * false-negative page_mapped(). 2284eef1b3baSKirill A. Shutemov */ 2285eef1b3baSKirill A. Shutemov if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { 2286eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2287eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 2288eef1b3baSKirill A. Shutemov } 2289eef1b3baSKirill A. Shutemov 2290eef1b3baSKirill A. Shutemov if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { 2291eef1b3baSKirill A. Shutemov /* Last compound_mapcount is gone. */ 229211fb9989SMel Gorman __dec_node_page_state(page, NR_ANON_THPS); 2293eef1b3baSKirill A. Shutemov if (TestClearPageDoubleMap(page)) { 2294eef1b3baSKirill A. Shutemov /* No need in mapcount reference anymore */ 2295eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2296eef1b3baSKirill A. Shutemov atomic_dec(&page[i]._mapcount); 2297eef1b3baSKirill A. Shutemov } 2298eef1b3baSKirill A. Shutemov } 2299eef1b3baSKirill A. Shutemov 2300eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2301eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2302e9b61f19SKirill A. Shutemov 2303e9b61f19SKirill A. Shutemov if (freeze) { 23042ac015e2SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) { 2305e9b61f19SKirill A. Shutemov page_remove_rmap(page + i, false); 2306e9b61f19SKirill A. Shutemov put_page(page + i); 2307e9b61f19SKirill A. Shutemov } 2308e9b61f19SKirill A. Shutemov } 2309eef1b3baSKirill A. Shutemov } 2310eef1b3baSKirill A. Shutemov 2311eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 231233f4751eSNaoya Horiguchi unsigned long address, bool freeze, struct page *page) 2313eef1b3baSKirill A. Shutemov { 2314eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2315ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2316eef1b3baSKirill A. Shutemov 23177269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 23186f4f13e8SJérôme Glisse address & HPAGE_PMD_MASK, 2319ac46d4f3SJérôme Glisse (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); 2320ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2321ac46d4f3SJérôme Glisse ptl = pmd_lock(vma->vm_mm, pmd); 232233f4751eSNaoya Horiguchi 232333f4751eSNaoya Horiguchi /* 232433f4751eSNaoya Horiguchi * If caller asks to setup a migration entries, we need a page to check 232533f4751eSNaoya Horiguchi * pmd against. Otherwise we can end up replacing wrong page. 232633f4751eSNaoya Horiguchi */ 232733f4751eSNaoya Horiguchi VM_BUG_ON(freeze && !page); 232833f4751eSNaoya Horiguchi if (page && page != pmd_page(*pmd)) 232933f4751eSNaoya Horiguchi goto out; 233033f4751eSNaoya Horiguchi 23315c7fb56eSDan Williams if (pmd_trans_huge(*pmd)) { 233233f4751eSNaoya Horiguchi page = pmd_page(*pmd); 2333e90309c9SKirill A. Shutemov if (PageMlocked(page)) 23345f737714SKirill A. Shutemov clear_page_mlock(page); 233584c3fc4eSZi Yan } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) 23365c7fb56eSDan Williams goto out; 2337ac46d4f3SJérôme Glisse __split_huge_pmd_locked(vma, pmd, range.start, freeze); 2338e90309c9SKirill A. Shutemov out: 2339eef1b3baSKirill A. Shutemov spin_unlock(ptl); 23404645b9feSJérôme Glisse /* 23414645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback. 23424645b9feSJérôme Glisse * They are 3 cases to consider inside __split_huge_pmd_locked(): 23434645b9feSJérôme Glisse * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious 23444645b9feSJérôme Glisse * 2) __split_huge_zero_page_pmd() read only zero page and any write 23454645b9feSJérôme Glisse * fault will trigger a flush_notify before pointing to a new page 23464645b9feSJérôme Glisse * (it is fine if the secondary mmu keeps pointing to the old zero 23474645b9feSJérôme Glisse * page in the meantime) 23484645b9feSJérôme Glisse * 3) Split a huge pmd into pte pointing to the same page. No need 23494645b9feSJérôme Glisse * to invalidate secondary tlb entry they are all still valid. 23504645b9feSJérôme Glisse * any further changes to individual pte will notify. So no need 23514645b9feSJérôme Glisse * to call mmu_notifier->invalidate_range() 23524645b9feSJérôme Glisse */ 2353ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 2354eef1b3baSKirill A. Shutemov } 2355eef1b3baSKirill A. Shutemov 2356fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2357fec89c10SKirill A. Shutemov bool freeze, struct page *page) 235894fcc585SAndrea Arcangeli { 2359f72e7dcdSHugh Dickins pgd_t *pgd; 2360c2febafcSKirill A. Shutemov p4d_t *p4d; 2361f72e7dcdSHugh Dickins pud_t *pud; 236294fcc585SAndrea Arcangeli pmd_t *pmd; 236394fcc585SAndrea Arcangeli 236478ddc534SKirill A. Shutemov pgd = pgd_offset(vma->vm_mm, address); 2365f72e7dcdSHugh Dickins if (!pgd_present(*pgd)) 2366f72e7dcdSHugh Dickins return; 2367f72e7dcdSHugh Dickins 2368c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, address); 2369c2febafcSKirill A. Shutemov if (!p4d_present(*p4d)) 2370c2febafcSKirill A. Shutemov return; 2371c2febafcSKirill A. Shutemov 2372c2febafcSKirill A. Shutemov pud = pud_offset(p4d, address); 2373f72e7dcdSHugh Dickins if (!pud_present(*pud)) 2374f72e7dcdSHugh Dickins return; 2375f72e7dcdSHugh Dickins 2376f72e7dcdSHugh Dickins pmd = pmd_offset(pud, address); 2377fec89c10SKirill A. Shutemov 237833f4751eSNaoya Horiguchi __split_huge_pmd(vma, pmd, address, freeze, page); 237994fcc585SAndrea Arcangeli } 238094fcc585SAndrea Arcangeli 2381e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 238294fcc585SAndrea Arcangeli unsigned long start, 238394fcc585SAndrea Arcangeli unsigned long end, 238494fcc585SAndrea Arcangeli long adjust_next) 238594fcc585SAndrea Arcangeli { 238694fcc585SAndrea Arcangeli /* 238794fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 238894fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 238994fcc585SAndrea Arcangeli * an huge pmd. 239094fcc585SAndrea Arcangeli */ 239194fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 239294fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 239394fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 2394fec89c10SKirill A. Shutemov split_huge_pmd_address(vma, start, false, NULL); 239594fcc585SAndrea Arcangeli 239694fcc585SAndrea Arcangeli /* 239794fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 239894fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 239994fcc585SAndrea Arcangeli * an huge pmd. 240094fcc585SAndrea Arcangeli */ 240194fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 240294fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 240394fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 2404fec89c10SKirill A. Shutemov split_huge_pmd_address(vma, end, false, NULL); 240594fcc585SAndrea Arcangeli 240694fcc585SAndrea Arcangeli /* 240794fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 240894fcc585SAndrea Arcangeli * vm_next->vm_start isn't page aligned and it could previously 240994fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 241094fcc585SAndrea Arcangeli */ 241194fcc585SAndrea Arcangeli if (adjust_next > 0) { 241294fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 241394fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 241494fcc585SAndrea Arcangeli nstart += adjust_next << PAGE_SHIFT; 241594fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 241694fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 241794fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 2418fec89c10SKirill A. Shutemov split_huge_pmd_address(next, nstart, false, NULL); 241994fcc585SAndrea Arcangeli } 242094fcc585SAndrea Arcangeli } 2421e9b61f19SKirill A. Shutemov 2422906f9cdfSHugh Dickins static void unmap_page(struct page *page) 2423e9b61f19SKirill A. Shutemov { 2424baa355fdSKirill A. Shutemov enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | 2425c7ab0d2fSKirill A. Shutemov TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; 2426666e5a40SMinchan Kim bool unmap_success; 2427e9b61f19SKirill A. Shutemov 2428e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageHead(page), page); 2429e9b61f19SKirill A. Shutemov 2430baa355fdSKirill A. Shutemov if (PageAnon(page)) 2431b5ff8161SNaoya Horiguchi ttu_flags |= TTU_SPLIT_FREEZE; 2432baa355fdSKirill A. Shutemov 2433666e5a40SMinchan Kim unmap_success = try_to_unmap(page, ttu_flags); 2434666e5a40SMinchan Kim VM_BUG_ON_PAGE(!unmap_success, page); 2435bd56086fSKirill A. Shutemov } 2436bd56086fSKirill A. Shutemov 2437906f9cdfSHugh Dickins static void remap_page(struct page *page) 2438e9b61f19SKirill A. Shutemov { 2439fec89c10SKirill A. Shutemov int i; 2440ace71a19SKirill A. Shutemov if (PageTransHuge(page)) { 2441ace71a19SKirill A. Shutemov remove_migration_ptes(page, page, true); 2442ace71a19SKirill A. Shutemov } else { 2443fec89c10SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2444fec89c10SKirill A. Shutemov remove_migration_ptes(page + i, page + i, true); 2445e9b61f19SKirill A. Shutemov } 2446ace71a19SKirill A. Shutemov } 2447e9b61f19SKirill A. Shutemov 24488df651c7SKirill A. Shutemov static void __split_huge_page_tail(struct page *head, int tail, 2449e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2450e9b61f19SKirill A. Shutemov { 2451e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 2452e9b61f19SKirill A. Shutemov 24538df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2454e9b61f19SKirill A. Shutemov 2455e9b61f19SKirill A. Shutemov /* 2456605ca5edSKonstantin Khlebnikov * Clone page flags before unfreezing refcount. 2457605ca5edSKonstantin Khlebnikov * 2458605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow flags change, 2459605ca5edSKonstantin Khlebnikov * for exmaple lock_page() which set PG_waiters. 2460e9b61f19SKirill A. Shutemov */ 2461e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2462e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2463e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2464e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 246538d8b4e6SHuang Ying (1L << PG_swapcache) | 2466e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2467e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2468e9b61f19SKirill A. Shutemov (1L << PG_active) | 24691899ad18SJohannes Weiner (1L << PG_workingset) | 2470e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2471b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 2472b8d3c4c3SMinchan Kim (1L << PG_dirty))); 2473e9b61f19SKirill A. Shutemov 2474173d9d9fSHugh Dickins /* ->mapping in first tail page is compound_mapcount */ 2475173d9d9fSHugh Dickins VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2476173d9d9fSHugh Dickins page_tail); 2477173d9d9fSHugh Dickins page_tail->mapping = head->mapping; 2478173d9d9fSHugh Dickins page_tail->index = head->index + tail; 2479173d9d9fSHugh Dickins 2480605ca5edSKonstantin Khlebnikov /* Page flags must be visible before we make the page non-compound. */ 2481e9b61f19SKirill A. Shutemov smp_wmb(); 2482e9b61f19SKirill A. Shutemov 2483605ca5edSKonstantin Khlebnikov /* 2484605ca5edSKonstantin Khlebnikov * Clear PageTail before unfreezing page refcount. 2485605ca5edSKonstantin Khlebnikov * 2486605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow put_page() 2487605ca5edSKonstantin Khlebnikov * which needs correct compound_head(). 2488605ca5edSKonstantin Khlebnikov */ 2489e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2490e9b61f19SKirill A. Shutemov 2491605ca5edSKonstantin Khlebnikov /* Finally unfreeze refcount. Additional reference from page cache. */ 2492605ca5edSKonstantin Khlebnikov page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || 2493605ca5edSKonstantin Khlebnikov PageSwapCache(head))); 2494605ca5edSKonstantin Khlebnikov 2495e9b61f19SKirill A. Shutemov if (page_is_young(head)) 2496e9b61f19SKirill A. Shutemov set_page_young(page_tail); 2497e9b61f19SKirill A. Shutemov if (page_is_idle(head)) 2498e9b61f19SKirill A. Shutemov set_page_idle(page_tail); 2499e9b61f19SKirill A. Shutemov 2500e9b61f19SKirill A. Shutemov page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); 250194723aafSMichal Hocko 250294723aafSMichal Hocko /* 250394723aafSMichal Hocko * always add to the tail because some iterators expect new 250494723aafSMichal Hocko * pages to show after the currently processed elements - e.g. 250594723aafSMichal Hocko * migrate_pages 250694723aafSMichal Hocko */ 2507e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2508e9b61f19SKirill A. Shutemov } 2509e9b61f19SKirill A. Shutemov 2510baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2511006d3ff2SHugh Dickins pgoff_t end, unsigned long flags) 2512e9b61f19SKirill A. Shutemov { 2513e9b61f19SKirill A. Shutemov struct page *head = compound_head(page); 2514f4b7e272SAndrey Ryabinin pg_data_t *pgdat = page_pgdat(head); 2515e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 25164101196bSMatthew Wilcox (Oracle) struct address_space *swap_cache = NULL; 25174101196bSMatthew Wilcox (Oracle) unsigned long offset = 0; 25188df651c7SKirill A. Shutemov int i; 2519e9b61f19SKirill A. Shutemov 2520f4b7e272SAndrey Ryabinin lruvec = mem_cgroup_page_lruvec(head, pgdat); 2521e9b61f19SKirill A. Shutemov 2522e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2523e9b61f19SKirill A. Shutemov mem_cgroup_split_huge_fixup(head); 2524e9b61f19SKirill A. Shutemov 25254101196bSMatthew Wilcox (Oracle) if (PageAnon(head) && PageSwapCache(head)) { 25264101196bSMatthew Wilcox (Oracle) swp_entry_t entry = { .val = page_private(head) }; 25274101196bSMatthew Wilcox (Oracle) 25284101196bSMatthew Wilcox (Oracle) offset = swp_offset(entry); 25294101196bSMatthew Wilcox (Oracle) swap_cache = swap_address_space(entry); 25304101196bSMatthew Wilcox (Oracle) xa_lock(&swap_cache->i_pages); 25314101196bSMatthew Wilcox (Oracle) } 25324101196bSMatthew Wilcox (Oracle) 2533baa355fdSKirill A. Shutemov for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { 25348df651c7SKirill A. Shutemov __split_huge_page_tail(head, i, lruvec, list); 2535baa355fdSKirill A. Shutemov /* Some pages can be beyond i_size: drop them from page cache */ 2536baa355fdSKirill A. Shutemov if (head[i].index >= end) { 25372d077d4bSHugh Dickins ClearPageDirty(head + i); 2538baa355fdSKirill A. Shutemov __delete_from_page_cache(head + i, NULL); 2539800d8c63SKirill A. Shutemov if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) 2540800d8c63SKirill A. Shutemov shmem_uncharge(head->mapping->host, 1); 2541baa355fdSKirill A. Shutemov put_page(head + i); 25424101196bSMatthew Wilcox (Oracle) } else if (!PageAnon(page)) { 25434101196bSMatthew Wilcox (Oracle) __xa_store(&head->mapping->i_pages, head[i].index, 25444101196bSMatthew Wilcox (Oracle) head + i, 0); 25454101196bSMatthew Wilcox (Oracle) } else if (swap_cache) { 25464101196bSMatthew Wilcox (Oracle) __xa_store(&swap_cache->i_pages, offset + i, 25474101196bSMatthew Wilcox (Oracle) head + i, 0); 2548baa355fdSKirill A. Shutemov } 2549baa355fdSKirill A. Shutemov } 2550e9b61f19SKirill A. Shutemov 2551e9b61f19SKirill A. Shutemov ClearPageCompound(head); 2552f7da677bSVlastimil Babka 2553f7da677bSVlastimil Babka split_page_owner(head, HPAGE_PMD_ORDER); 2554f7da677bSVlastimil Babka 2555baa355fdSKirill A. Shutemov /* See comment in __split_huge_page_tail() */ 2556baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2557aa5dc07fSMatthew Wilcox /* Additional pin to swap cache */ 25584101196bSMatthew Wilcox (Oracle) if (PageSwapCache(head)) { 255938d8b4e6SHuang Ying page_ref_add(head, 2); 25604101196bSMatthew Wilcox (Oracle) xa_unlock(&swap_cache->i_pages); 25614101196bSMatthew Wilcox (Oracle) } else { 2562baa355fdSKirill A. Shutemov page_ref_inc(head); 25634101196bSMatthew Wilcox (Oracle) } 2564baa355fdSKirill A. Shutemov } else { 2565aa5dc07fSMatthew Wilcox /* Additional pin to page cache */ 2566baa355fdSKirill A. Shutemov page_ref_add(head, 2); 2567b93b0163SMatthew Wilcox xa_unlock(&head->mapping->i_pages); 2568baa355fdSKirill A. Shutemov } 2569baa355fdSKirill A. Shutemov 2570f4b7e272SAndrey Ryabinin spin_unlock_irqrestore(&pgdat->lru_lock, flags); 2571e9b61f19SKirill A. Shutemov 2572906f9cdfSHugh Dickins remap_page(head); 2573e9b61f19SKirill A. Shutemov 2574e9b61f19SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) { 2575e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2576e9b61f19SKirill A. Shutemov if (subpage == page) 2577e9b61f19SKirill A. Shutemov continue; 2578e9b61f19SKirill A. Shutemov unlock_page(subpage); 2579e9b61f19SKirill A. Shutemov 2580e9b61f19SKirill A. Shutemov /* 2581e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2582e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2583e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2584e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2585e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2586e9b61f19SKirill A. Shutemov */ 2587e9b61f19SKirill A. Shutemov put_page(subpage); 2588e9b61f19SKirill A. Shutemov } 2589e9b61f19SKirill A. Shutemov } 2590e9b61f19SKirill A. Shutemov 2591b20ce5e0SKirill A. Shutemov int total_mapcount(struct page *page) 2592b20ce5e0SKirill A. Shutemov { 2593dd78feddSKirill A. Shutemov int i, compound, ret; 2594b20ce5e0SKirill A. Shutemov 2595b20ce5e0SKirill A. Shutemov VM_BUG_ON_PAGE(PageTail(page), page); 2596b20ce5e0SKirill A. Shutemov 2597b20ce5e0SKirill A. Shutemov if (likely(!PageCompound(page))) 2598b20ce5e0SKirill A. Shutemov return atomic_read(&page->_mapcount) + 1; 2599b20ce5e0SKirill A. Shutemov 2600dd78feddSKirill A. Shutemov compound = compound_mapcount(page); 2601b20ce5e0SKirill A. Shutemov if (PageHuge(page)) 2602dd78feddSKirill A. Shutemov return compound; 2603dd78feddSKirill A. Shutemov ret = compound; 2604b20ce5e0SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2605b20ce5e0SKirill A. Shutemov ret += atomic_read(&page[i]._mapcount) + 1; 2606dd78feddSKirill A. Shutemov /* File pages has compound_mapcount included in _mapcount */ 2607dd78feddSKirill A. Shutemov if (!PageAnon(page)) 2608dd78feddSKirill A. Shutemov return ret - compound * HPAGE_PMD_NR; 2609b20ce5e0SKirill A. Shutemov if (PageDoubleMap(page)) 2610b20ce5e0SKirill A. Shutemov ret -= HPAGE_PMD_NR; 2611b20ce5e0SKirill A. Shutemov return ret; 2612b20ce5e0SKirill A. Shutemov } 2613b20ce5e0SKirill A. Shutemov 2614e9b61f19SKirill A. Shutemov /* 26156d0a07edSAndrea Arcangeli * This calculates accurately how many mappings a transparent hugepage 26166d0a07edSAndrea Arcangeli * has (unlike page_mapcount() which isn't fully accurate). This full 26176d0a07edSAndrea Arcangeli * accuracy is primarily needed to know if copy-on-write faults can 26186d0a07edSAndrea Arcangeli * reuse the page and change the mapping to read-write instead of 26196d0a07edSAndrea Arcangeli * copying them. At the same time this returns the total_mapcount too. 26206d0a07edSAndrea Arcangeli * 26216d0a07edSAndrea Arcangeli * The function returns the highest mapcount any one of the subpages 26226d0a07edSAndrea Arcangeli * has. If the return value is one, even if different processes are 26236d0a07edSAndrea Arcangeli * mapping different subpages of the transparent hugepage, they can 26246d0a07edSAndrea Arcangeli * all reuse it, because each process is reusing a different subpage. 26256d0a07edSAndrea Arcangeli * 26266d0a07edSAndrea Arcangeli * The total_mapcount is instead counting all virtual mappings of the 26276d0a07edSAndrea Arcangeli * subpages. If the total_mapcount is equal to "one", it tells the 26286d0a07edSAndrea Arcangeli * caller all mappings belong to the same "mm" and in turn the 26296d0a07edSAndrea Arcangeli * anon_vma of the transparent hugepage can become the vma->anon_vma 26306d0a07edSAndrea Arcangeli * local one as no other process may be mapping any of the subpages. 26316d0a07edSAndrea Arcangeli * 26326d0a07edSAndrea Arcangeli * It would be more accurate to replace page_mapcount() with 26336d0a07edSAndrea Arcangeli * page_trans_huge_mapcount(), however we only use 26346d0a07edSAndrea Arcangeli * page_trans_huge_mapcount() in the copy-on-write faults where we 26356d0a07edSAndrea Arcangeli * need full accuracy to avoid breaking page pinning, because 26366d0a07edSAndrea Arcangeli * page_trans_huge_mapcount() is slower than page_mapcount(). 26376d0a07edSAndrea Arcangeli */ 26386d0a07edSAndrea Arcangeli int page_trans_huge_mapcount(struct page *page, int *total_mapcount) 26396d0a07edSAndrea Arcangeli { 26406d0a07edSAndrea Arcangeli int i, ret, _total_mapcount, mapcount; 26416d0a07edSAndrea Arcangeli 26426d0a07edSAndrea Arcangeli /* hugetlbfs shouldn't call it */ 26436d0a07edSAndrea Arcangeli VM_BUG_ON_PAGE(PageHuge(page), page); 26446d0a07edSAndrea Arcangeli 26456d0a07edSAndrea Arcangeli if (likely(!PageTransCompound(page))) { 26466d0a07edSAndrea Arcangeli mapcount = atomic_read(&page->_mapcount) + 1; 26476d0a07edSAndrea Arcangeli if (total_mapcount) 26486d0a07edSAndrea Arcangeli *total_mapcount = mapcount; 26496d0a07edSAndrea Arcangeli return mapcount; 26506d0a07edSAndrea Arcangeli } 26516d0a07edSAndrea Arcangeli 26526d0a07edSAndrea Arcangeli page = compound_head(page); 26536d0a07edSAndrea Arcangeli 26546d0a07edSAndrea Arcangeli _total_mapcount = ret = 0; 26556d0a07edSAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 26566d0a07edSAndrea Arcangeli mapcount = atomic_read(&page[i]._mapcount) + 1; 26576d0a07edSAndrea Arcangeli ret = max(ret, mapcount); 26586d0a07edSAndrea Arcangeli _total_mapcount += mapcount; 26596d0a07edSAndrea Arcangeli } 26606d0a07edSAndrea Arcangeli if (PageDoubleMap(page)) { 26616d0a07edSAndrea Arcangeli ret -= 1; 26626d0a07edSAndrea Arcangeli _total_mapcount -= HPAGE_PMD_NR; 26636d0a07edSAndrea Arcangeli } 26646d0a07edSAndrea Arcangeli mapcount = compound_mapcount(page); 26656d0a07edSAndrea Arcangeli ret += mapcount; 26666d0a07edSAndrea Arcangeli _total_mapcount += mapcount; 26676d0a07edSAndrea Arcangeli if (total_mapcount) 26686d0a07edSAndrea Arcangeli *total_mapcount = _total_mapcount; 26696d0a07edSAndrea Arcangeli return ret; 26706d0a07edSAndrea Arcangeli } 26716d0a07edSAndrea Arcangeli 2672b8f593cdSHuang Ying /* Racy check whether the huge page can be split */ 2673b8f593cdSHuang Ying bool can_split_huge_page(struct page *page, int *pextra_pins) 2674b8f593cdSHuang Ying { 2675b8f593cdSHuang Ying int extra_pins; 2676b8f593cdSHuang Ying 2677aa5dc07fSMatthew Wilcox /* Additional pins from page cache */ 2678b8f593cdSHuang Ying if (PageAnon(page)) 2679b8f593cdSHuang Ying extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; 2680b8f593cdSHuang Ying else 2681b8f593cdSHuang Ying extra_pins = HPAGE_PMD_NR; 2682b8f593cdSHuang Ying if (pextra_pins) 2683b8f593cdSHuang Ying *pextra_pins = extra_pins; 2684b8f593cdSHuang Ying return total_mapcount(page) == page_count(page) - extra_pins - 1; 2685b8f593cdSHuang Ying } 2686b8f593cdSHuang Ying 26876d0a07edSAndrea Arcangeli /* 2688e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2689e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2690e9b61f19SKirill A. Shutemov * 2691e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2692e9b61f19SKirill A. Shutemov * The huge page must be locked. 2693e9b61f19SKirill A. Shutemov * 2694e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2695e9b61f19SKirill A. Shutemov * 2696e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2697e9b61f19SKirill A. Shutemov * the hugepage. 2698e9b61f19SKirill A. Shutemov * 2699e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2700e9b61f19SKirill A. Shutemov * they are not mapped. 2701e9b61f19SKirill A. Shutemov * 2702e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2703e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2704e9b61f19SKirill A. Shutemov * us. 2705e9b61f19SKirill A. Shutemov */ 2706e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2707e9b61f19SKirill A. Shutemov { 2708e9b61f19SKirill A. Shutemov struct page *head = compound_head(page); 2709a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); 2710a8803e6cSWei Yang struct deferred_split *ds_queue = get_deferred_split_queue(head); 2711baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2712baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2713baa355fdSKirill A. Shutemov int count, mapcount, extra_pins, ret; 2714d9654322SKirill A. Shutemov bool mlocked; 27150b9b6fffSKirill A. Shutemov unsigned long flags; 2716006d3ff2SHugh Dickins pgoff_t end; 2717e9b61f19SKirill A. Shutemov 2718cb829624SWei Yang VM_BUG_ON_PAGE(is_huge_zero_page(head), head); 2719a8803e6cSWei Yang VM_BUG_ON_PAGE(!PageLocked(head), head); 2720a8803e6cSWei Yang VM_BUG_ON_PAGE(!PageCompound(head), head); 2721e9b61f19SKirill A. Shutemov 2722a8803e6cSWei Yang if (PageWriteback(head)) 272359807685SHuang Ying return -EBUSY; 272459807685SHuang Ying 2725baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2726e9b61f19SKirill A. Shutemov /* 2727baa355fdSKirill A. Shutemov * The caller does not necessarily hold an mmap_sem that would 2728baa355fdSKirill A. Shutemov * prevent the anon_vma disappearing so we first we take a 2729baa355fdSKirill A. Shutemov * reference to it and then lock the anon_vma for write. This 2730baa355fdSKirill A. Shutemov * is similar to page_lock_anon_vma_read except the write lock 2731baa355fdSKirill A. Shutemov * is taken to serialise against parallel split or collapse 2732baa355fdSKirill A. Shutemov * operations. 2733e9b61f19SKirill A. Shutemov */ 2734e9b61f19SKirill A. Shutemov anon_vma = page_get_anon_vma(head); 2735e9b61f19SKirill A. Shutemov if (!anon_vma) { 2736e9b61f19SKirill A. Shutemov ret = -EBUSY; 2737e9b61f19SKirill A. Shutemov goto out; 2738e9b61f19SKirill A. Shutemov } 2739006d3ff2SHugh Dickins end = -1; 2740baa355fdSKirill A. Shutemov mapping = NULL; 2741e9b61f19SKirill A. Shutemov anon_vma_lock_write(anon_vma); 2742baa355fdSKirill A. Shutemov } else { 2743baa355fdSKirill A. Shutemov mapping = head->mapping; 2744baa355fdSKirill A. Shutemov 2745baa355fdSKirill A. Shutemov /* Truncated ? */ 2746baa355fdSKirill A. Shutemov if (!mapping) { 2747baa355fdSKirill A. Shutemov ret = -EBUSY; 2748baa355fdSKirill A. Shutemov goto out; 2749baa355fdSKirill A. Shutemov } 2750baa355fdSKirill A. Shutemov 2751baa355fdSKirill A. Shutemov anon_vma = NULL; 2752baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 2753006d3ff2SHugh Dickins 2754006d3ff2SHugh Dickins /* 2755006d3ff2SHugh Dickins *__split_huge_page() may need to trim off pages beyond EOF: 2756006d3ff2SHugh Dickins * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, 2757006d3ff2SHugh Dickins * which cannot be nested inside the page tree lock. So note 2758006d3ff2SHugh Dickins * end now: i_size itself may be changed at any moment, but 2759006d3ff2SHugh Dickins * head page lock is good enough to serialize the trimming. 2760006d3ff2SHugh Dickins */ 2761006d3ff2SHugh Dickins end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); 2762baa355fdSKirill A. Shutemov } 2763e9b61f19SKirill A. Shutemov 2764e9b61f19SKirill A. Shutemov /* 2765906f9cdfSHugh Dickins * Racy check if we can split the page, before unmap_page() will 2766e9b61f19SKirill A. Shutemov * split PMDs 2767e9b61f19SKirill A. Shutemov */ 2768b8f593cdSHuang Ying if (!can_split_huge_page(head, &extra_pins)) { 2769e9b61f19SKirill A. Shutemov ret = -EBUSY; 2770e9b61f19SKirill A. Shutemov goto out_unlock; 2771e9b61f19SKirill A. Shutemov } 2772e9b61f19SKirill A. Shutemov 2773a8803e6cSWei Yang mlocked = PageMlocked(head); 2774906f9cdfSHugh Dickins unmap_page(head); 2775e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(compound_mapcount(head), head); 2776e9b61f19SKirill A. Shutemov 2777d9654322SKirill A. Shutemov /* Make sure the page is not on per-CPU pagevec as it takes pin */ 2778d9654322SKirill A. Shutemov if (mlocked) 2779d9654322SKirill A. Shutemov lru_add_drain(); 2780d9654322SKirill A. Shutemov 2781baa355fdSKirill A. Shutemov /* prevent PageLRU to go away from under us, and freeze lru stats */ 2782f4b7e272SAndrey Ryabinin spin_lock_irqsave(&pgdata->lru_lock, flags); 2783baa355fdSKirill A. Shutemov 2784baa355fdSKirill A. Shutemov if (mapping) { 2785aa5dc07fSMatthew Wilcox XA_STATE(xas, &mapping->i_pages, page_index(head)); 2786baa355fdSKirill A. Shutemov 2787baa355fdSKirill A. Shutemov /* 2788aa5dc07fSMatthew Wilcox * Check if the head page is present in page cache. 2789baa355fdSKirill A. Shutemov * We assume all tail are present too, if head is there. 2790baa355fdSKirill A. Shutemov */ 2791aa5dc07fSMatthew Wilcox xa_lock(&mapping->i_pages); 2792aa5dc07fSMatthew Wilcox if (xas_load(&xas) != head) 2793baa355fdSKirill A. Shutemov goto fail; 2794baa355fdSKirill A. Shutemov } 2795baa355fdSKirill A. Shutemov 27960139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 2797364c1eebSYang Shi spin_lock(&ds_queue->split_queue_lock); 2798e9b61f19SKirill A. Shutemov count = page_count(head); 2799e9b61f19SKirill A. Shutemov mapcount = total_mapcount(head); 2800baa355fdSKirill A. Shutemov if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { 28019a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(head))) { 2802364c1eebSYang Shi ds_queue->split_queue_len--; 28039a982250SKirill A. Shutemov list_del(page_deferred_list(head)); 28049a982250SKirill A. Shutemov } 2805afb97172SWei Yang spin_unlock(&ds_queue->split_queue_lock); 280606d3eff6SKirill A. Shutemov if (mapping) { 2807a8803e6cSWei Yang if (PageSwapBacked(head)) 2808a8803e6cSWei Yang __dec_node_page_state(head, NR_SHMEM_THPS); 280906d3eff6SKirill A. Shutemov else 2810a8803e6cSWei Yang __dec_node_page_state(head, NR_FILE_THPS); 281106d3eff6SKirill A. Shutemov } 281206d3eff6SKirill A. Shutemov 2813006d3ff2SHugh Dickins __split_huge_page(page, list, end, flags); 281459807685SHuang Ying if (PageSwapCache(head)) { 281559807685SHuang Ying swp_entry_t entry = { .val = page_private(head) }; 281659807685SHuang Ying 281759807685SHuang Ying ret = split_swap_cluster(entry); 281859807685SHuang Ying } else 2819e9b61f19SKirill A. Shutemov ret = 0; 2820baa355fdSKirill A. Shutemov } else { 2821baa355fdSKirill A. Shutemov if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { 2822e9b61f19SKirill A. Shutemov pr_alert("total_mapcount: %u, page_count(): %u\n", 2823e9b61f19SKirill A. Shutemov mapcount, count); 2824e9b61f19SKirill A. Shutemov if (PageTail(page)) 2825e9b61f19SKirill A. Shutemov dump_page(head, NULL); 2826bd56086fSKirill A. Shutemov dump_page(page, "total_mapcount(head) > 0"); 2827e9b61f19SKirill A. Shutemov BUG(); 2828baa355fdSKirill A. Shutemov } 2829364c1eebSYang Shi spin_unlock(&ds_queue->split_queue_lock); 2830baa355fdSKirill A. Shutemov fail: if (mapping) 2831b93b0163SMatthew Wilcox xa_unlock(&mapping->i_pages); 2832f4b7e272SAndrey Ryabinin spin_unlock_irqrestore(&pgdata->lru_lock, flags); 2833906f9cdfSHugh Dickins remap_page(head); 2834e9b61f19SKirill A. Shutemov ret = -EBUSY; 2835e9b61f19SKirill A. Shutemov } 2836e9b61f19SKirill A. Shutemov 2837e9b61f19SKirill A. Shutemov out_unlock: 2838baa355fdSKirill A. Shutemov if (anon_vma) { 2839e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 2840e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 2841baa355fdSKirill A. Shutemov } 2842baa355fdSKirill A. Shutemov if (mapping) 2843baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 2844e9b61f19SKirill A. Shutemov out: 2845e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 2846e9b61f19SKirill A. Shutemov return ret; 2847e9b61f19SKirill A. Shutemov } 28489a982250SKirill A. Shutemov 28499a982250SKirill A. Shutemov void free_transhuge_page(struct page *page) 28509a982250SKirill A. Shutemov { 285187eaceb3SYang Shi struct deferred_split *ds_queue = get_deferred_split_queue(page); 28529a982250SKirill A. Shutemov unsigned long flags; 28539a982250SKirill A. Shutemov 2854364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28559a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(page))) { 2856364c1eebSYang Shi ds_queue->split_queue_len--; 28579a982250SKirill A. Shutemov list_del(page_deferred_list(page)); 28589a982250SKirill A. Shutemov } 2859364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28609a982250SKirill A. Shutemov free_compound_page(page); 28619a982250SKirill A. Shutemov } 28629a982250SKirill A. Shutemov 28639a982250SKirill A. Shutemov void deferred_split_huge_page(struct page *page) 28649a982250SKirill A. Shutemov { 286587eaceb3SYang Shi struct deferred_split *ds_queue = get_deferred_split_queue(page); 286687eaceb3SYang Shi #ifdef CONFIG_MEMCG 286787eaceb3SYang Shi struct mem_cgroup *memcg = compound_head(page)->mem_cgroup; 286887eaceb3SYang Shi #endif 28699a982250SKirill A. Shutemov unsigned long flags; 28709a982250SKirill A. Shutemov 28719a982250SKirill A. Shutemov VM_BUG_ON_PAGE(!PageTransHuge(page), page); 28729a982250SKirill A. Shutemov 287387eaceb3SYang Shi /* 287487eaceb3SYang Shi * The try_to_unmap() in page reclaim path might reach here too, 287587eaceb3SYang Shi * this may cause a race condition to corrupt deferred split queue. 287687eaceb3SYang Shi * And, if page reclaim is already handling the same page, it is 287787eaceb3SYang Shi * unnecessary to handle it again in shrinker. 287887eaceb3SYang Shi * 287987eaceb3SYang Shi * Check PageSwapCache to determine if the page is being 288087eaceb3SYang Shi * handled by page reclaim since THP swap would add the page into 288187eaceb3SYang Shi * swap cache before calling try_to_unmap(). 288287eaceb3SYang Shi */ 288387eaceb3SYang Shi if (PageSwapCache(page)) 288487eaceb3SYang Shi return; 288587eaceb3SYang Shi 2886364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28879a982250SKirill A. Shutemov if (list_empty(page_deferred_list(page))) { 2888f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 2889364c1eebSYang Shi list_add_tail(page_deferred_list(page), &ds_queue->split_queue); 2890364c1eebSYang Shi ds_queue->split_queue_len++; 289187eaceb3SYang Shi #ifdef CONFIG_MEMCG 289287eaceb3SYang Shi if (memcg) 289387eaceb3SYang Shi memcg_set_shrinker_bit(memcg, page_to_nid(page), 289487eaceb3SYang Shi deferred_split_shrinker.id); 289587eaceb3SYang Shi #endif 28969a982250SKirill A. Shutemov } 2897364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28989a982250SKirill A. Shutemov } 28999a982250SKirill A. Shutemov 29009a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 29019a982250SKirill A. Shutemov struct shrink_control *sc) 29029a982250SKirill A. Shutemov { 2903a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2904364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 290587eaceb3SYang Shi 290687eaceb3SYang Shi #ifdef CONFIG_MEMCG 290787eaceb3SYang Shi if (sc->memcg) 290887eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 290987eaceb3SYang Shi #endif 2910364c1eebSYang Shi return READ_ONCE(ds_queue->split_queue_len); 29119a982250SKirill A. Shutemov } 29129a982250SKirill A. Shutemov 29139a982250SKirill A. Shutemov static unsigned long deferred_split_scan(struct shrinker *shrink, 29149a982250SKirill A. Shutemov struct shrink_control *sc) 29159a982250SKirill A. Shutemov { 2916a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2917364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 29189a982250SKirill A. Shutemov unsigned long flags; 29199a982250SKirill A. Shutemov LIST_HEAD(list), *pos, *next; 29209a982250SKirill A. Shutemov struct page *page; 29219a982250SKirill A. Shutemov int split = 0; 29229a982250SKirill A. Shutemov 292387eaceb3SYang Shi #ifdef CONFIG_MEMCG 292487eaceb3SYang Shi if (sc->memcg) 292587eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 292687eaceb3SYang Shi #endif 292787eaceb3SYang Shi 2928364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 29299a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 2930364c1eebSYang Shi list_for_each_safe(pos, next, &ds_queue->split_queue) { 29319a982250SKirill A. Shutemov page = list_entry((void *)pos, struct page, mapping); 29329a982250SKirill A. Shutemov page = compound_head(page); 2933e3ae1953SKirill A. Shutemov if (get_page_unless_zero(page)) { 2934e3ae1953SKirill A. Shutemov list_move(page_deferred_list(page), &list); 2935e3ae1953SKirill A. Shutemov } else { 2936e3ae1953SKirill A. Shutemov /* We lost race with put_compound_page() */ 29379a982250SKirill A. Shutemov list_del_init(page_deferred_list(page)); 2938364c1eebSYang Shi ds_queue->split_queue_len--; 29399a982250SKirill A. Shutemov } 2940e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 2941e3ae1953SKirill A. Shutemov break; 29429a982250SKirill A. Shutemov } 2943364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 29449a982250SKirill A. Shutemov 29459a982250SKirill A. Shutemov list_for_each_safe(pos, next, &list) { 29469a982250SKirill A. Shutemov page = list_entry((void *)pos, struct page, mapping); 2947fa41b900SKirill A. Shutemov if (!trylock_page(page)) 2948fa41b900SKirill A. Shutemov goto next; 29499a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 29509a982250SKirill A. Shutemov if (!split_huge_page(page)) 29519a982250SKirill A. Shutemov split++; 29529a982250SKirill A. Shutemov unlock_page(page); 2953fa41b900SKirill A. Shutemov next: 29549a982250SKirill A. Shutemov put_page(page); 29559a982250SKirill A. Shutemov } 29569a982250SKirill A. Shutemov 2957364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 2958364c1eebSYang Shi list_splice_tail(&list, &ds_queue->split_queue); 2959364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 29609a982250SKirill A. Shutemov 2961cb8d68ecSKirill A. Shutemov /* 2962cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 2963cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 2964cb8d68ecSKirill A. Shutemov */ 2965364c1eebSYang Shi if (!split && list_empty(&ds_queue->split_queue)) 2966cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 2967cb8d68ecSKirill A. Shutemov return split; 29689a982250SKirill A. Shutemov } 29699a982250SKirill A. Shutemov 29709a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker = { 29719a982250SKirill A. Shutemov .count_objects = deferred_split_count, 29729a982250SKirill A. Shutemov .scan_objects = deferred_split_scan, 29739a982250SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 297487eaceb3SYang Shi .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | 297587eaceb3SYang Shi SHRINKER_NONSLAB, 29769a982250SKirill A. Shutemov }; 297749071d43SKirill A. Shutemov 297849071d43SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 297949071d43SKirill A. Shutemov static int split_huge_pages_set(void *data, u64 val) 298049071d43SKirill A. Shutemov { 298149071d43SKirill A. Shutemov struct zone *zone; 298249071d43SKirill A. Shutemov struct page *page; 298349071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 298449071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 298549071d43SKirill A. Shutemov 298649071d43SKirill A. Shutemov if (val != 1) 298749071d43SKirill A. Shutemov return -EINVAL; 298849071d43SKirill A. Shutemov 298949071d43SKirill A. Shutemov for_each_populated_zone(zone) { 299049071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 299149071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 299249071d43SKirill A. Shutemov if (!pfn_valid(pfn)) 299349071d43SKirill A. Shutemov continue; 299449071d43SKirill A. Shutemov 299549071d43SKirill A. Shutemov page = pfn_to_page(pfn); 299649071d43SKirill A. Shutemov if (!get_page_unless_zero(page)) 299749071d43SKirill A. Shutemov continue; 299849071d43SKirill A. Shutemov 299949071d43SKirill A. Shutemov if (zone != page_zone(page)) 300049071d43SKirill A. Shutemov goto next; 300149071d43SKirill A. Shutemov 3002baa355fdSKirill A. Shutemov if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) 300349071d43SKirill A. Shutemov goto next; 300449071d43SKirill A. Shutemov 300549071d43SKirill A. Shutemov total++; 300649071d43SKirill A. Shutemov lock_page(page); 300749071d43SKirill A. Shutemov if (!split_huge_page(page)) 300849071d43SKirill A. Shutemov split++; 300949071d43SKirill A. Shutemov unlock_page(page); 301049071d43SKirill A. Shutemov next: 301149071d43SKirill A. Shutemov put_page(page); 301249071d43SKirill A. Shutemov } 301349071d43SKirill A. Shutemov } 301449071d43SKirill A. Shutemov 3015145bdaa1SYang Shi pr_info("%lu of %lu THP split\n", split, total); 301649071d43SKirill A. Shutemov 301749071d43SKirill A. Shutemov return 0; 301849071d43SKirill A. Shutemov } 3019f1287869Szhong jiang DEFINE_DEBUGFS_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, 302049071d43SKirill A. Shutemov "%llu\n"); 302149071d43SKirill A. Shutemov 302249071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 302349071d43SKirill A. Shutemov { 3024d9f7979cSGreg Kroah-Hartman debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 302549071d43SKirill A. Shutemov &split_huge_pages_fops); 302649071d43SKirill A. Shutemov return 0; 302749071d43SKirill A. Shutemov } 302849071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 302949071d43SKirill A. Shutemov #endif 3030616b8371SZi Yan 3031616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 3032616b8371SZi Yan void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 3033616b8371SZi Yan struct page *page) 3034616b8371SZi Yan { 3035616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3036616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3037616b8371SZi Yan unsigned long address = pvmw->address; 3038616b8371SZi Yan pmd_t pmdval; 3039616b8371SZi Yan swp_entry_t entry; 3040ab6e3d09SNaoya Horiguchi pmd_t pmdswp; 3041616b8371SZi Yan 3042616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 3043616b8371SZi Yan return; 3044616b8371SZi Yan 3045616b8371SZi Yan flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); 3046*8a8683adSHuang Ying pmdval = pmdp_invalidate(vma, address, pvmw->pmd); 3047616b8371SZi Yan if (pmd_dirty(pmdval)) 3048616b8371SZi Yan set_page_dirty(page); 3049616b8371SZi Yan entry = make_migration_entry(page, pmd_write(pmdval)); 3050ab6e3d09SNaoya Horiguchi pmdswp = swp_entry_to_pmd(entry); 3051ab6e3d09SNaoya Horiguchi if (pmd_soft_dirty(pmdval)) 3052ab6e3d09SNaoya Horiguchi pmdswp = pmd_swp_mksoft_dirty(pmdswp); 3053ab6e3d09SNaoya Horiguchi set_pmd_at(mm, address, pvmw->pmd, pmdswp); 3054616b8371SZi Yan page_remove_rmap(page, true); 3055616b8371SZi Yan put_page(page); 3056616b8371SZi Yan } 3057616b8371SZi Yan 3058616b8371SZi Yan void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 3059616b8371SZi Yan { 3060616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3061616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3062616b8371SZi Yan unsigned long address = pvmw->address; 3063616b8371SZi Yan unsigned long mmun_start = address & HPAGE_PMD_MASK; 3064616b8371SZi Yan pmd_t pmde; 3065616b8371SZi Yan swp_entry_t entry; 3066616b8371SZi Yan 3067616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 3068616b8371SZi Yan return; 3069616b8371SZi Yan 3070616b8371SZi Yan entry = pmd_to_swp_entry(*pvmw->pmd); 3071616b8371SZi Yan get_page(new); 3072616b8371SZi Yan pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); 3073ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pvmw->pmd)) 3074ab6e3d09SNaoya Horiguchi pmde = pmd_mksoft_dirty(pmde); 3075616b8371SZi Yan if (is_write_migration_entry(entry)) 3076f55e1014SLinus Torvalds pmde = maybe_pmd_mkwrite(pmde, vma); 3077616b8371SZi Yan 3078616b8371SZi Yan flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); 3079e71769aeSNaoya Horiguchi if (PageAnon(new)) 3080616b8371SZi Yan page_add_anon_rmap(new, vma, mmun_start, true); 3081e71769aeSNaoya Horiguchi else 3082e71769aeSNaoya Horiguchi page_add_file_rmap(new, true); 3083616b8371SZi Yan set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); 3084e125fe40SKirill A. Shutemov if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) 3085616b8371SZi Yan mlock_vma_page(new); 3086616b8371SZi Yan update_mmu_cache_pmd(vma, address, pvmw->pmd); 3087616b8371SZi Yan } 3088616b8371SZi Yan #endif 3089