171e3aac0SAndrea Arcangeli /* 271e3aac0SAndrea Arcangeli * Copyright (C) 2009 Red Hat, Inc. 371e3aac0SAndrea Arcangeli * 471e3aac0SAndrea Arcangeli * This work is licensed under the terms of the GNU GPL, version 2. See 571e3aac0SAndrea Arcangeli * the COPYING file in the top-level directory. 671e3aac0SAndrea Arcangeli */ 771e3aac0SAndrea Arcangeli 8ae3a8c1cSAndrew Morton #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9ae3a8c1cSAndrew Morton 1071e3aac0SAndrea Arcangeli #include <linux/mm.h> 1171e3aac0SAndrea Arcangeli #include <linux/sched.h> 12f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 136a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 1471e3aac0SAndrea Arcangeli #include <linux/highmem.h> 1571e3aac0SAndrea Arcangeli #include <linux/hugetlb.h> 1671e3aac0SAndrea Arcangeli #include <linux/mmu_notifier.h> 1771e3aac0SAndrea Arcangeli #include <linux/rmap.h> 1871e3aac0SAndrea Arcangeli #include <linux/swap.h> 1997ae1749SKirill A. Shutemov #include <linux/shrinker.h> 20ba76149fSAndrea Arcangeli #include <linux/mm_inline.h> 21e9b61f19SKirill A. Shutemov #include <linux/swapops.h> 224897c765SMatthew Wilcox #include <linux/dax.h> 23ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 24878aee7dSAndrea Arcangeli #include <linux/freezer.h> 25f25748e3SDan Williams #include <linux/pfn_t.h> 26a664b2d8SAndrea Arcangeli #include <linux/mman.h> 273565fce3SDan Williams #include <linux/memremap.h> 28325adeb5SRalf Baechle #include <linux/pagemap.h> 2949071d43SKirill A. Shutemov #include <linux/debugfs.h> 304daae3b4SMel Gorman #include <linux/migrate.h> 3143b5fbbdSSasha Levin #include <linux/hashtable.h> 326b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 3333c3fc71SVladimir Davydov #include <linux/page_idle.h> 34baa355fdSKirill A. Shutemov #include <linux/shmem_fs.h> 356b31d595SMichal Hocko #include <linux/oom.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 /* 428bfa3f9aSJianguo Wu * By default transparent hugepage support is disabled in order that avoid 438bfa3f9aSJianguo Wu * to risk increase the memory footprint of applications without a guaranteed 448bfa3f9aSJianguo Wu * benefit. When transparent hugepage support is enabled, is for all mappings, 458bfa3f9aSJianguo Wu * 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 656fcb52a5SAaron Lu static struct page *get_huge_zero_page(void) 6697ae1749SKirill A. Shutemov { 6797ae1749SKirill A. Shutemov struct page *zero_page; 6897ae1749SKirill A. Shutemov retry: 6997ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 704db0c3c2SJason Low return READ_ONCE(huge_zero_page); 7197ae1749SKirill A. Shutemov 7297ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 7397ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 74d8a8e1f0SKirill A. Shutemov if (!zero_page) { 75d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 765918d10aSKirill A. Shutemov return NULL; 77d8a8e1f0SKirill A. Shutemov } 78d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC); 7997ae1749SKirill A. Shutemov preempt_disable(); 805918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 8197ae1749SKirill A. Shutemov preempt_enable(); 825ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 8397ae1749SKirill A. Shutemov goto retry; 8497ae1749SKirill A. Shutemov } 8597ae1749SKirill A. Shutemov 8697ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 8797ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 8897ae1749SKirill A. Shutemov preempt_enable(); 894db0c3c2SJason Low return READ_ONCE(huge_zero_page); 9097ae1749SKirill A. Shutemov } 9197ae1749SKirill A. Shutemov 926fcb52a5SAaron Lu static void put_huge_zero_page(void) 9397ae1749SKirill A. Shutemov { 9497ae1749SKirill A. Shutemov /* 9597ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 9697ae1749SKirill A. Shutemov * last reference. 9797ae1749SKirill A. Shutemov */ 9897ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 9997ae1749SKirill A. Shutemov } 10097ae1749SKirill A. Shutemov 1016fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 1026fcb52a5SAaron Lu { 1036fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1046fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1056fcb52a5SAaron Lu 1066fcb52a5SAaron Lu if (!get_huge_zero_page()) 1076fcb52a5SAaron Lu return NULL; 1086fcb52a5SAaron Lu 1096fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1106fcb52a5SAaron Lu put_huge_zero_page(); 1116fcb52a5SAaron Lu 1126fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1136fcb52a5SAaron Lu } 1146fcb52a5SAaron Lu 1156fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 1166fcb52a5SAaron Lu { 1176fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1186fcb52a5SAaron Lu put_huge_zero_page(); 1196fcb52a5SAaron Lu } 1206fcb52a5SAaron Lu 12148896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 12297ae1749SKirill A. Shutemov struct shrink_control *sc) 12397ae1749SKirill A. Shutemov { 12497ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 12597ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 12648896466SGlauber Costa } 12797ae1749SKirill A. Shutemov 12848896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 12948896466SGlauber Costa struct shrink_control *sc) 13048896466SGlauber Costa { 13197ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 1325918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 1335918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 1345ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 13548896466SGlauber Costa return HPAGE_PMD_NR; 13697ae1749SKirill A. Shutemov } 13797ae1749SKirill A. Shutemov 13897ae1749SKirill A. Shutemov return 0; 13997ae1749SKirill A. Shutemov } 14097ae1749SKirill A. Shutemov 14197ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 14248896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 14348896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 14497ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 14597ae1749SKirill A. Shutemov }; 14697ae1749SKirill A. Shutemov 14771e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 14871e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 14971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 15071e3aac0SAndrea Arcangeli { 151444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 152444eb2a4SMel Gorman return sprintf(buf, "[always] madvise never\n"); 153444eb2a4SMel Gorman else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) 154444eb2a4SMel Gorman return sprintf(buf, "always [madvise] never\n"); 155444eb2a4SMel Gorman else 156444eb2a4SMel Gorman return sprintf(buf, "always madvise [never]\n"); 15771e3aac0SAndrea Arcangeli } 158444eb2a4SMel Gorman 15971e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 16071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 16171e3aac0SAndrea Arcangeli const char *buf, size_t count) 16271e3aac0SAndrea Arcangeli { 16321440d7eSDavid Rientjes ssize_t ret = count; 164ba76149fSAndrea Arcangeli 16521440d7eSDavid Rientjes if (!memcmp("always", buf, 16621440d7eSDavid Rientjes min(sizeof("always")-1, count))) { 16721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 16821440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 16921440d7eSDavid Rientjes } else if (!memcmp("madvise", buf, 17021440d7eSDavid Rientjes min(sizeof("madvise")-1, count))) { 17121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 17221440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 17321440d7eSDavid Rientjes } else if (!memcmp("never", buf, 17421440d7eSDavid Rientjes min(sizeof("never")-1, count))) { 17521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 17621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 17721440d7eSDavid Rientjes } else 17821440d7eSDavid Rientjes ret = -EINVAL; 179ba76149fSAndrea Arcangeli 180ba76149fSAndrea Arcangeli if (ret > 0) { 181b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 182ba76149fSAndrea Arcangeli if (err) 183ba76149fSAndrea Arcangeli ret = err; 184ba76149fSAndrea Arcangeli } 185ba76149fSAndrea Arcangeli return ret; 18671e3aac0SAndrea Arcangeli } 18771e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 18871e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 18971e3aac0SAndrea Arcangeli 190b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 19171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 19271e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 19371e3aac0SAndrea Arcangeli { 194e27e6151SBen Hutchings return sprintf(buf, "%d\n", 195e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 19671e3aac0SAndrea Arcangeli } 197e27e6151SBen Hutchings 198b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 19971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 20071e3aac0SAndrea Arcangeli const char *buf, size_t count, 20171e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 20271e3aac0SAndrea Arcangeli { 203e27e6151SBen Hutchings unsigned long value; 204e27e6151SBen Hutchings int ret; 205e27e6151SBen Hutchings 206e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 207e27e6151SBen Hutchings if (ret < 0) 208e27e6151SBen Hutchings return ret; 209e27e6151SBen Hutchings if (value > 1) 21071e3aac0SAndrea Arcangeli return -EINVAL; 21171e3aac0SAndrea Arcangeli 212e27e6151SBen Hutchings if (value) 213e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 214e27e6151SBen Hutchings else 215e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 216e27e6151SBen Hutchings 21771e3aac0SAndrea Arcangeli return count; 21871e3aac0SAndrea Arcangeli } 21971e3aac0SAndrea Arcangeli 22071e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 22171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 22271e3aac0SAndrea Arcangeli { 223444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 22421440d7eSDavid Rientjes return sprintf(buf, "[always] defer defer+madvise madvise never\n"); 225444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 22621440d7eSDavid Rientjes return sprintf(buf, "always [defer] defer+madvise madvise never\n"); 22721440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 22821440d7eSDavid Rientjes return sprintf(buf, "always defer [defer+madvise] madvise never\n"); 22921440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 23021440d7eSDavid Rientjes return sprintf(buf, "always defer defer+madvise [madvise] never\n"); 23121440d7eSDavid Rientjes return sprintf(buf, "always defer defer+madvise madvise [never]\n"); 23271e3aac0SAndrea Arcangeli } 23321440d7eSDavid Rientjes 23471e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 23571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 23671e3aac0SAndrea Arcangeli const char *buf, size_t count) 23771e3aac0SAndrea Arcangeli { 23821440d7eSDavid Rientjes if (!memcmp("always", buf, 23921440d7eSDavid Rientjes min(sizeof("always")-1, count))) { 24021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 24121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 24221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 24321440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 24421440d7eSDavid Rientjes } else if (!memcmp("defer+madvise", buf, 24521440d7eSDavid Rientjes min(sizeof("defer+madvise")-1, count))) { 24621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 24721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 24821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 24921440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 2504fad7fb6SDavid Rientjes } else if (!memcmp("defer", buf, 2514fad7fb6SDavid Rientjes min(sizeof("defer")-1, count))) { 2524fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 2534fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 2544fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 2554fad7fb6SDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 25621440d7eSDavid Rientjes } else if (!memcmp("madvise", buf, 25721440d7eSDavid Rientjes min(sizeof("madvise")-1, count))) { 25821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 25921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 26021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 26121440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 26221440d7eSDavid Rientjes } else if (!memcmp("never", buf, 26321440d7eSDavid Rientjes min(sizeof("never")-1, count))) { 26421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 26521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 26621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 26721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 26821440d7eSDavid Rientjes } else 26921440d7eSDavid Rientjes return -EINVAL; 27021440d7eSDavid Rientjes 27121440d7eSDavid Rientjes return count; 27271e3aac0SAndrea Arcangeli } 27371e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 27471e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 27571e3aac0SAndrea Arcangeli 27679da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 27779da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 27879da5407SKirill A. Shutemov { 279b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 28079da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 28179da5407SKirill A. Shutemov } 28279da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 28379da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 28479da5407SKirill A. Shutemov { 285b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 28679da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 28779da5407SKirill A. Shutemov } 28879da5407SKirill A. Shutemov static struct kobj_attribute use_zero_page_attr = 28979da5407SKirill A. Shutemov __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); 29049920d28SHugh Dickins 29149920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 29249920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 29349920d28SHugh Dickins { 29449920d28SHugh Dickins return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); 29549920d28SHugh Dickins } 29649920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 29749920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 29849920d28SHugh Dickins 29971e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 30071e3aac0SAndrea Arcangeli static ssize_t debug_cow_show(struct kobject *kobj, 30171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 30271e3aac0SAndrea Arcangeli { 303b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 30471e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 30571e3aac0SAndrea Arcangeli } 30671e3aac0SAndrea Arcangeli static ssize_t debug_cow_store(struct kobject *kobj, 30771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 30871e3aac0SAndrea Arcangeli const char *buf, size_t count) 30971e3aac0SAndrea Arcangeli { 310b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 31171e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 31271e3aac0SAndrea Arcangeli } 31371e3aac0SAndrea Arcangeli static struct kobj_attribute debug_cow_attr = 31471e3aac0SAndrea Arcangeli __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); 31571e3aac0SAndrea Arcangeli #endif /* CONFIG_DEBUG_VM */ 31671e3aac0SAndrea Arcangeli 31771e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 31871e3aac0SAndrea Arcangeli &enabled_attr.attr, 31971e3aac0SAndrea Arcangeli &defrag_attr.attr, 32079da5407SKirill A. Shutemov &use_zero_page_attr.attr, 32149920d28SHugh Dickins &hpage_pmd_size_attr.attr, 322e496cf3dSKirill A. Shutemov #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) 3235a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 3245a6e75f8SKirill A. Shutemov #endif 32571e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 32671e3aac0SAndrea Arcangeli &debug_cow_attr.attr, 32771e3aac0SAndrea Arcangeli #endif 32871e3aac0SAndrea Arcangeli NULL, 32971e3aac0SAndrea Arcangeli }; 33071e3aac0SAndrea Arcangeli 3318aa95a21SArvind Yadav static const struct attribute_group hugepage_attr_group = { 33271e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 333ba76149fSAndrea Arcangeli }; 334ba76149fSAndrea Arcangeli 335569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 336569e5590SShaohua Li { 337569e5590SShaohua Li int err; 338569e5590SShaohua Li 339569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 340569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 341ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 342569e5590SShaohua Li return -ENOMEM; 343569e5590SShaohua Li } 344569e5590SShaohua Li 345569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 346569e5590SShaohua Li if (err) { 347ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 348569e5590SShaohua Li goto delete_obj; 349569e5590SShaohua Li } 350569e5590SShaohua Li 351569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 352569e5590SShaohua Li if (err) { 353ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 354569e5590SShaohua Li goto remove_hp_group; 355569e5590SShaohua Li } 356569e5590SShaohua Li 357569e5590SShaohua Li return 0; 358569e5590SShaohua Li 359569e5590SShaohua Li remove_hp_group: 360569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 361569e5590SShaohua Li delete_obj: 362569e5590SShaohua Li kobject_put(*hugepage_kobj); 363569e5590SShaohua Li return err; 364569e5590SShaohua Li } 365569e5590SShaohua Li 366569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 367569e5590SShaohua Li { 368569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 369569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 370569e5590SShaohua Li kobject_put(hugepage_kobj); 371569e5590SShaohua Li } 372569e5590SShaohua Li #else 373569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 374569e5590SShaohua Li { 375569e5590SShaohua Li return 0; 376569e5590SShaohua Li } 377569e5590SShaohua Li 378569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 379569e5590SShaohua Li { 380569e5590SShaohua Li } 38171e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 38271e3aac0SAndrea Arcangeli 38371e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 38471e3aac0SAndrea Arcangeli { 38571e3aac0SAndrea Arcangeli int err; 386569e5590SShaohua Li struct kobject *hugepage_kobj; 38771e3aac0SAndrea Arcangeli 3884b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 3894b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 390569e5590SShaohua Li return -EINVAL; 3914b7167b9SAndrea Arcangeli } 3924b7167b9SAndrea Arcangeli 393ff20c2e0SKirill A. Shutemov /* 394ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 395ff20c2e0SKirill A. Shutemov */ 396ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); 397ff20c2e0SKirill A. Shutemov /* 398ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 399ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 400ff20c2e0SKirill A. Shutemov */ 401ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 402ff20c2e0SKirill A. Shutemov 403569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 404569e5590SShaohua Li if (err) 40565ebb64fSKirill A. Shutemov goto err_sysfs; 406ba76149fSAndrea Arcangeli 407b46e756fSKirill A. Shutemov err = khugepaged_init(); 408ba76149fSAndrea Arcangeli if (err) 40965ebb64fSKirill A. Shutemov goto err_slab; 410ba76149fSAndrea Arcangeli 41165ebb64fSKirill A. Shutemov err = register_shrinker(&huge_zero_page_shrinker); 41265ebb64fSKirill A. Shutemov if (err) 41365ebb64fSKirill A. Shutemov goto err_hzp_shrinker; 4149a982250SKirill A. Shutemov err = register_shrinker(&deferred_split_shrinker); 4159a982250SKirill A. Shutemov if (err) 4169a982250SKirill A. Shutemov goto err_split_shrinker; 41797ae1749SKirill A. Shutemov 41897562cd2SRik van Riel /* 41997562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 42097562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 42197562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 42297562cd2SRik van Riel */ 42379553da2SKirill A. Shutemov if (totalram_pages < (512 << (20 - PAGE_SHIFT))) { 42497562cd2SRik van Riel transparent_hugepage_flags = 0; 42579553da2SKirill A. Shutemov return 0; 42679553da2SKirill A. Shutemov } 42797562cd2SRik van Riel 42879553da2SKirill A. Shutemov err = start_stop_khugepaged(); 42965ebb64fSKirill A. Shutemov if (err) 43065ebb64fSKirill A. Shutemov goto err_khugepaged; 431ba76149fSAndrea Arcangeli 432569e5590SShaohua Li return 0; 43365ebb64fSKirill A. Shutemov err_khugepaged: 4349a982250SKirill A. Shutemov unregister_shrinker(&deferred_split_shrinker); 4359a982250SKirill A. Shutemov err_split_shrinker: 43665ebb64fSKirill A. Shutemov unregister_shrinker(&huge_zero_page_shrinker); 43765ebb64fSKirill A. Shutemov err_hzp_shrinker: 438b46e756fSKirill A. Shutemov khugepaged_destroy(); 43965ebb64fSKirill A. Shutemov err_slab: 440569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 44165ebb64fSKirill A. Shutemov err_sysfs: 442ba76149fSAndrea Arcangeli return err; 44371e3aac0SAndrea Arcangeli } 444a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 44571e3aac0SAndrea Arcangeli 44671e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 44771e3aac0SAndrea Arcangeli { 44871e3aac0SAndrea Arcangeli int ret = 0; 44971e3aac0SAndrea Arcangeli if (!str) 45071e3aac0SAndrea Arcangeli goto out; 45171e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 45271e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 45371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 45471e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 45571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 45671e3aac0SAndrea Arcangeli ret = 1; 45771e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 45871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 45971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46071e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 46171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46271e3aac0SAndrea Arcangeli ret = 1; 46371e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 46471e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 46571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46671e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 46771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46871e3aac0SAndrea Arcangeli ret = 1; 46971e3aac0SAndrea Arcangeli } 47071e3aac0SAndrea Arcangeli out: 47171e3aac0SAndrea Arcangeli if (!ret) 472ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 47371e3aac0SAndrea Arcangeli return ret; 47471e3aac0SAndrea Arcangeli } 47571e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 47671e3aac0SAndrea Arcangeli 477b32967ffSMel Gorman pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 47871e3aac0SAndrea Arcangeli { 47971e3aac0SAndrea Arcangeli if (likely(vma->vm_flags & VM_WRITE)) 48071e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 48171e3aac0SAndrea Arcangeli return pmd; 48271e3aac0SAndrea Arcangeli } 48371e3aac0SAndrea Arcangeli 4849a982250SKirill A. Shutemov static inline struct list_head *page_deferred_list(struct page *page) 4859a982250SKirill A. Shutemov { 4869a982250SKirill A. Shutemov /* 4879a982250SKirill A. Shutemov * ->lru in the tail pages is occupied by compound_head. 4889a982250SKirill A. Shutemov * Let's use ->mapping + ->index in the second tail page as list_head. 4899a982250SKirill A. Shutemov */ 4909a982250SKirill A. Shutemov return (struct list_head *)&page[2].mapping; 4919a982250SKirill A. Shutemov } 4929a982250SKirill A. Shutemov 4939a982250SKirill A. Shutemov void prep_transhuge_page(struct page *page) 4949a982250SKirill A. Shutemov { 4959a982250SKirill A. Shutemov /* 4969a982250SKirill A. Shutemov * we use page->mapping and page->indexlru in second tail page 4979a982250SKirill A. Shutemov * as list_head: assuming THP order >= 2 4989a982250SKirill A. Shutemov */ 4999a982250SKirill A. Shutemov 5009a982250SKirill A. Shutemov INIT_LIST_HEAD(page_deferred_list(page)); 5019a982250SKirill A. Shutemov set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); 5029a982250SKirill A. Shutemov } 5039a982250SKirill A. Shutemov 50474d2fad1SToshi Kani unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len, 50574d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 50674d2fad1SToshi Kani { 50774d2fad1SToshi Kani unsigned long addr; 50874d2fad1SToshi Kani loff_t off_end = off + len; 50974d2fad1SToshi Kani loff_t off_align = round_up(off, size); 51074d2fad1SToshi Kani unsigned long len_pad; 51174d2fad1SToshi Kani 51274d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 51374d2fad1SToshi Kani return 0; 51474d2fad1SToshi Kani 51574d2fad1SToshi Kani len_pad = len + size; 51674d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 51774d2fad1SToshi Kani return 0; 51874d2fad1SToshi Kani 51974d2fad1SToshi Kani addr = current->mm->get_unmapped_area(filp, 0, len_pad, 52074d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 52174d2fad1SToshi Kani if (IS_ERR_VALUE(addr)) 52274d2fad1SToshi Kani return 0; 52374d2fad1SToshi Kani 52474d2fad1SToshi Kani addr += (off - addr) & (size - 1); 52574d2fad1SToshi Kani return addr; 52674d2fad1SToshi Kani } 52774d2fad1SToshi Kani 52874d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 52974d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 53074d2fad1SToshi Kani { 53174d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 53274d2fad1SToshi Kani 53374d2fad1SToshi Kani if (addr) 53474d2fad1SToshi Kani goto out; 53574d2fad1SToshi Kani if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) 53674d2fad1SToshi Kani goto out; 53774d2fad1SToshi Kani 53874d2fad1SToshi Kani addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); 53974d2fad1SToshi Kani if (addr) 54074d2fad1SToshi Kani return addr; 54174d2fad1SToshi Kani 54274d2fad1SToshi Kani out: 54374d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 54474d2fad1SToshi Kani } 54574d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 54674d2fad1SToshi Kani 54782b0f8c3SJan Kara static int __do_huge_pmd_anonymous_page(struct vm_fault *vmf, struct page *page, 548bae473a4SKirill A. Shutemov gfp_t gfp) 54971e3aac0SAndrea Arcangeli { 55082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 55100501b53SJohannes Weiner struct mem_cgroup *memcg; 55271e3aac0SAndrea Arcangeli pgtable_t pgtable; 55382b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 5546b31d595SMichal Hocko int ret = 0; 55571e3aac0SAndrea Arcangeli 556309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 55700501b53SJohannes Weiner 558bae473a4SKirill A. Shutemov if (mem_cgroup_try_charge(page, vma->vm_mm, gfp, &memcg, true)) { 5596b251fc9SAndrea Arcangeli put_page(page); 5606b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 5616b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 5626b251fc9SAndrea Arcangeli } 56371e3aac0SAndrea Arcangeli 564bae473a4SKirill A. Shutemov pgtable = pte_alloc_one(vma->vm_mm, haddr); 56500501b53SJohannes Weiner if (unlikely(!pgtable)) { 5666b31d595SMichal Hocko ret = VM_FAULT_OOM; 5676b31d595SMichal Hocko goto release; 56800501b53SJohannes Weiner } 56900501b53SJohannes Weiner 570c79b57e4SHuang Ying clear_huge_page(page, vmf->address, HPAGE_PMD_NR); 57152f37629SMinchan Kim /* 57252f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 57352f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 57452f37629SMinchan Kim * write. 57552f37629SMinchan Kim */ 57671e3aac0SAndrea Arcangeli __SetPageUptodate(page); 57771e3aac0SAndrea Arcangeli 57882b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 57982b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 5806b31d595SMichal Hocko goto unlock_release; 58171e3aac0SAndrea Arcangeli } else { 58271e3aac0SAndrea Arcangeli pmd_t entry; 5836b251fc9SAndrea Arcangeli 5846b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 5856b31d595SMichal Hocko if (ret) 5866b31d595SMichal Hocko goto unlock_release; 5876b31d595SMichal Hocko 5886b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 5896b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 5906b251fc9SAndrea Arcangeli int ret; 5916b251fc9SAndrea Arcangeli 59282b0f8c3SJan Kara spin_unlock(vmf->ptl); 593f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, true); 5946b251fc9SAndrea Arcangeli put_page(page); 595bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 59682b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 5976b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 5986b251fc9SAndrea Arcangeli return ret; 5996b251fc9SAndrea Arcangeli } 6006b251fc9SAndrea Arcangeli 6013122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 6023122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 603d281ee61SKirill A. Shutemov page_add_new_anon_rmap(page, vma, haddr, true); 604f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(page, memcg, false, true); 60500501b53SJohannes Weiner lru_cache_add_active_or_unevictable(page, vma); 60682b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 60782b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 608bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 609bae473a4SKirill A. Shutemov atomic_long_inc(&vma->vm_mm->nr_ptes); 61082b0f8c3SJan Kara spin_unlock(vmf->ptl); 6116b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 61271e3aac0SAndrea Arcangeli } 61371e3aac0SAndrea Arcangeli 614aa2e878eSDavid Rientjes return 0; 6156b31d595SMichal Hocko unlock_release: 6166b31d595SMichal Hocko spin_unlock(vmf->ptl); 6176b31d595SMichal Hocko release: 6186b31d595SMichal Hocko if (pgtable) 6196b31d595SMichal Hocko pte_free(vma->vm_mm, pgtable); 6206b31d595SMichal Hocko mem_cgroup_cancel_charge(page, memcg, true); 6216b31d595SMichal Hocko put_page(page); 6226b31d595SMichal Hocko return ret; 6236b31d595SMichal Hocko 62471e3aac0SAndrea Arcangeli } 62571e3aac0SAndrea Arcangeli 626444eb2a4SMel Gorman /* 62721440d7eSDavid Rientjes * always: directly stall for all thp allocations 62821440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 62921440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 63021440d7eSDavid Rientjes * fail if not immediately available 63121440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 63221440d7eSDavid Rientjes * available 63321440d7eSDavid Rientjes * never: never stall for any thp allocation 634444eb2a4SMel Gorman */ 635444eb2a4SMel Gorman static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) 6360bbbc0b3SAndrea Arcangeli { 63721440d7eSDavid Rientjes const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); 638444eb2a4SMel Gorman 63921440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 64025160354SVlastimil Babka return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 64121440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 64221440d7eSDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 64321440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 64421440d7eSDavid Rientjes return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : 64521440d7eSDavid Rientjes __GFP_KSWAPD_RECLAIM); 64621440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 64721440d7eSDavid Rientjes return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : 64821440d7eSDavid Rientjes 0); 64925160354SVlastimil Babka return GFP_TRANSHUGE_LIGHT; 650444eb2a4SMel Gorman } 651444eb2a4SMel Gorman 652c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 653d295e341SKirill A. Shutemov static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 65497ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 6555918d10aSKirill A. Shutemov struct page *zero_page) 656fc9fe822SKirill A. Shutemov { 657fc9fe822SKirill A. Shutemov pmd_t entry; 6587c414164SAndrew Morton if (!pmd_none(*pmd)) 6597c414164SAndrew Morton return false; 6605918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 661fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 66212c9d70bSMatthew Wilcox if (pgtable) 6636b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 664fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 665e1f56c89SKirill A. Shutemov atomic_long_inc(&mm->nr_ptes); 6667c414164SAndrew Morton return true; 667fc9fe822SKirill A. Shutemov } 668fc9fe822SKirill A. Shutemov 66982b0f8c3SJan Kara int do_huge_pmd_anonymous_page(struct vm_fault *vmf) 67071e3aac0SAndrea Arcangeli { 67182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 672077fcf11SAneesh Kumar K.V gfp_t gfp; 67371e3aac0SAndrea Arcangeli struct page *page; 67482b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 67571e3aac0SAndrea Arcangeli 676128ec037SKirill A. Shutemov if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) 677c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 67871e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 67971e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 6806d50e60cSDavid Rientjes if (unlikely(khugepaged_enter(vma, vma->vm_flags))) 681ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 68282b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 683bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 68479da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 68580371957SKirill A. Shutemov pgtable_t pgtable; 6865918d10aSKirill A. Shutemov struct page *zero_page; 6873ea41e62SKirill A. Shutemov bool set; 6886b251fc9SAndrea Arcangeli int ret; 689bae473a4SKirill A. Shutemov pgtable = pte_alloc_one(vma->vm_mm, haddr); 69080371957SKirill A. Shutemov if (unlikely(!pgtable)) 69180371957SKirill A. Shutemov return VM_FAULT_OOM; 6926fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 6935918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 694bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 69597ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 696c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 69797ae1749SKirill A. Shutemov } 69882b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 6996b251fc9SAndrea Arcangeli ret = 0; 7006b251fc9SAndrea Arcangeli set = false; 70182b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 7026b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 7036b31d595SMichal Hocko if (ret) { 7046b31d595SMichal Hocko spin_unlock(vmf->ptl); 7056b31d595SMichal Hocko } else if (userfaultfd_missing(vma)) { 70682b0f8c3SJan Kara spin_unlock(vmf->ptl); 70782b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 7086b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 7096b251fc9SAndrea Arcangeli } else { 710bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 71182b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 71282b0f8c3SJan Kara spin_unlock(vmf->ptl); 7136b251fc9SAndrea Arcangeli set = true; 7146b251fc9SAndrea Arcangeli } 7156b251fc9SAndrea Arcangeli } else 71682b0f8c3SJan Kara spin_unlock(vmf->ptl); 7176fcb52a5SAaron Lu if (!set) 718bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 7196b251fc9SAndrea Arcangeli return ret; 72080371957SKirill A. Shutemov } 721444eb2a4SMel Gorman gfp = alloc_hugepage_direct_gfpmask(vma); 722077fcf11SAneesh Kumar K.V page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); 72381ab4201SAndi Kleen if (unlikely(!page)) { 72481ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 725c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 72681ab4201SAndi Kleen } 7279a982250SKirill A. Shutemov prep_transhuge_page(page); 72882b0f8c3SJan Kara return __do_huge_pmd_anonymous_page(vmf, page, gfp); 72971e3aac0SAndrea Arcangeli } 73071e3aac0SAndrea Arcangeli 731ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 7323b6521f5SOliver O'Halloran pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, 7333b6521f5SOliver O'Halloran pgtable_t pgtable) 7345cad465dSMatthew Wilcox { 7355cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 7365cad465dSMatthew Wilcox pmd_t entry; 7375cad465dSMatthew Wilcox spinlock_t *ptl; 7385cad465dSMatthew Wilcox 7395cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 740f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 741f25748e3SDan Williams if (pfn_t_devmap(pfn)) 742f25748e3SDan Williams entry = pmd_mkdevmap(entry); 7435cad465dSMatthew Wilcox if (write) { 7445cad465dSMatthew Wilcox entry = pmd_mkyoung(pmd_mkdirty(entry)); 7455cad465dSMatthew Wilcox entry = maybe_pmd_mkwrite(entry, vma); 7465cad465dSMatthew Wilcox } 7473b6521f5SOliver O'Halloran 7483b6521f5SOliver O'Halloran if (pgtable) { 7493b6521f5SOliver O'Halloran pgtable_trans_huge_deposit(mm, pmd, pgtable); 7503b6521f5SOliver O'Halloran atomic_long_inc(&mm->nr_ptes); 7513b6521f5SOliver O'Halloran } 7523b6521f5SOliver O'Halloran 7535cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 7545cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 7555cad465dSMatthew Wilcox spin_unlock(ptl); 7565cad465dSMatthew Wilcox } 7575cad465dSMatthew Wilcox 7585cad465dSMatthew Wilcox int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 759f25748e3SDan Williams pmd_t *pmd, pfn_t pfn, bool write) 7605cad465dSMatthew Wilcox { 7615cad465dSMatthew Wilcox pgprot_t pgprot = vma->vm_page_prot; 7623b6521f5SOliver O'Halloran pgtable_t pgtable = NULL; 7635cad465dSMatthew Wilcox /* 7645cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 7655cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 7665cad465dSMatthew Wilcox * can't support a 'special' bit. 7675cad465dSMatthew Wilcox */ 7685cad465dSMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 7695cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 7705cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 7715cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 772f25748e3SDan Williams BUG_ON(!pfn_t_devmap(pfn)); 7735cad465dSMatthew Wilcox 7745cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 7755cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 776308a047cSBorislav Petkov 7773b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) { 7783b6521f5SOliver O'Halloran pgtable = pte_alloc_one(vma->vm_mm, addr); 7793b6521f5SOliver O'Halloran if (!pgtable) 7803b6521f5SOliver O'Halloran return VM_FAULT_OOM; 7813b6521f5SOliver O'Halloran } 7823b6521f5SOliver O'Halloran 783308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 784308a047cSBorislav Petkov 7853b6521f5SOliver O'Halloran insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write, pgtable); 786ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 7875cad465dSMatthew Wilcox } 788dee41079SDan Williams EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); 7895cad465dSMatthew Wilcox 790a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 791a00cc7d9SMatthew Wilcox static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 792a00cc7d9SMatthew Wilcox { 793a00cc7d9SMatthew Wilcox if (likely(vma->vm_flags & VM_WRITE)) 794a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 795a00cc7d9SMatthew Wilcox return pud; 796a00cc7d9SMatthew Wilcox } 797a00cc7d9SMatthew Wilcox 798a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 799a00cc7d9SMatthew Wilcox pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) 800a00cc7d9SMatthew Wilcox { 801a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 802a00cc7d9SMatthew Wilcox pud_t entry; 803a00cc7d9SMatthew Wilcox spinlock_t *ptl; 804a00cc7d9SMatthew Wilcox 805a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 806a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 807a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 808a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 809a00cc7d9SMatthew Wilcox if (write) { 810a00cc7d9SMatthew Wilcox entry = pud_mkyoung(pud_mkdirty(entry)); 811a00cc7d9SMatthew Wilcox entry = maybe_pud_mkwrite(entry, vma); 812a00cc7d9SMatthew Wilcox } 813a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 814a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 815a00cc7d9SMatthew Wilcox spin_unlock(ptl); 816a00cc7d9SMatthew Wilcox } 817a00cc7d9SMatthew Wilcox 818a00cc7d9SMatthew Wilcox int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 819a00cc7d9SMatthew Wilcox pud_t *pud, pfn_t pfn, bool write) 820a00cc7d9SMatthew Wilcox { 821a00cc7d9SMatthew Wilcox pgprot_t pgprot = vma->vm_page_prot; 822a00cc7d9SMatthew Wilcox /* 823a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 824a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 825a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 826a00cc7d9SMatthew Wilcox */ 827a00cc7d9SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 828a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 829a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 830a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 831a00cc7d9SMatthew Wilcox BUG_ON(!pfn_t_devmap(pfn)); 832a00cc7d9SMatthew Wilcox 833a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 834a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 835a00cc7d9SMatthew Wilcox 836a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 837a00cc7d9SMatthew Wilcox 838a00cc7d9SMatthew Wilcox insert_pfn_pud(vma, addr, pud, pfn, pgprot, write); 839a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 840a00cc7d9SMatthew Wilcox } 841a00cc7d9SMatthew Wilcox EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); 842a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 843a00cc7d9SMatthew Wilcox 8443565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 8453565fce3SDan Williams pmd_t *pmd) 8463565fce3SDan Williams { 8473565fce3SDan Williams pmd_t _pmd; 8483565fce3SDan Williams 8493565fce3SDan Williams /* 8503565fce3SDan Williams * We should set the dirty bit only for FOLL_WRITE but for now 8513565fce3SDan Williams * the dirty bit in the pmd is meaningless. And if the dirty 8523565fce3SDan Williams * bit will become meaningful and we'll only set it with 8533565fce3SDan Williams * FOLL_WRITE, an atomic set_bit will be required on the pmd to 8543565fce3SDan Williams * set the young bit, instead of the current set_pmd_at. 8553565fce3SDan Williams */ 8563565fce3SDan Williams _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); 8573565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 8583565fce3SDan Williams pmd, _pmd, 1)) 8593565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 8603565fce3SDan Williams } 8613565fce3SDan Williams 8623565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 8633565fce3SDan Williams pmd_t *pmd, int flags) 8643565fce3SDan Williams { 8653565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 8663565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 8673565fce3SDan Williams struct dev_pagemap *pgmap; 8683565fce3SDan Williams struct page *page; 8693565fce3SDan Williams 8703565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 8713565fce3SDan Williams 8728310d48bSKeno Fischer /* 8738310d48bSKeno Fischer * When we COW a devmap PMD entry, we split it into PTEs, so we should 8748310d48bSKeno Fischer * not be in this function with `flags & FOLL_COW` set. 8758310d48bSKeno Fischer */ 8768310d48bSKeno Fischer WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); 8778310d48bSKeno Fischer 8783565fce3SDan Williams if (flags & FOLL_WRITE && !pmd_write(*pmd)) 8793565fce3SDan Williams return NULL; 8803565fce3SDan Williams 8813565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 8823565fce3SDan Williams /* pass */; 8833565fce3SDan Williams else 8843565fce3SDan Williams return NULL; 8853565fce3SDan Williams 8863565fce3SDan Williams if (flags & FOLL_TOUCH) 8873565fce3SDan Williams touch_pmd(vma, addr, pmd); 8883565fce3SDan Williams 8893565fce3SDan Williams /* 8903565fce3SDan Williams * device mapped pages can only be returned if the 8913565fce3SDan Williams * caller will manage the page reference count. 8923565fce3SDan Williams */ 8933565fce3SDan Williams if (!(flags & FOLL_GET)) 8943565fce3SDan Williams return ERR_PTR(-EEXIST); 8953565fce3SDan Williams 8963565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 8973565fce3SDan Williams pgmap = get_dev_pagemap(pfn, NULL); 8983565fce3SDan Williams if (!pgmap) 8993565fce3SDan Williams return ERR_PTR(-EFAULT); 9003565fce3SDan Williams page = pfn_to_page(pfn); 9013565fce3SDan Williams get_page(page); 9023565fce3SDan Williams put_dev_pagemap(pgmap); 9033565fce3SDan Williams 9043565fce3SDan Williams return page; 9053565fce3SDan Williams } 9063565fce3SDan Williams 90771e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 90871e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 90971e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 91071e3aac0SAndrea Arcangeli { 911c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 91271e3aac0SAndrea Arcangeli struct page *src_page; 91371e3aac0SAndrea Arcangeli pmd_t pmd; 91412c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 915628d47ceSKirill A. Shutemov int ret = -ENOMEM; 91671e3aac0SAndrea Arcangeli 917628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 918628d47ceSKirill A. Shutemov if (!vma_is_anonymous(vma)) 919628d47ceSKirill A. Shutemov return 0; 920628d47ceSKirill A. Shutemov 92171e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(dst_mm, addr); 92271e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 92371e3aac0SAndrea Arcangeli goto out; 92471e3aac0SAndrea Arcangeli 925c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 926c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 927c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 92871e3aac0SAndrea Arcangeli 92971e3aac0SAndrea Arcangeli ret = -EAGAIN; 93071e3aac0SAndrea Arcangeli pmd = *src_pmd; 93184c3fc4eSZi Yan 93284c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 93384c3fc4eSZi Yan if (unlikely(is_swap_pmd(pmd))) { 93484c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(pmd); 93584c3fc4eSZi Yan 93684c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(pmd)); 93784c3fc4eSZi Yan if (is_write_migration_entry(entry)) { 93884c3fc4eSZi Yan make_migration_entry_read(&entry); 93984c3fc4eSZi Yan pmd = swp_entry_to_pmd(entry); 940ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*src_pmd)) 941ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 94284c3fc4eSZi Yan set_pmd_at(src_mm, addr, src_pmd, pmd); 94384c3fc4eSZi Yan } 944*dd8a67f9SZi Yan add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 945*dd8a67f9SZi Yan atomic_long_inc(&dst_mm->nr_ptes); 946*dd8a67f9SZi Yan pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 94784c3fc4eSZi Yan set_pmd_at(dst_mm, addr, dst_pmd, pmd); 94884c3fc4eSZi Yan ret = 0; 94984c3fc4eSZi Yan goto out_unlock; 95084c3fc4eSZi Yan } 95184c3fc4eSZi Yan #endif 95284c3fc4eSZi Yan 953628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 95471e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 95571e3aac0SAndrea Arcangeli goto out_unlock; 95671e3aac0SAndrea Arcangeli } 957fc9fe822SKirill A. Shutemov /* 958c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 959fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 960fc9fe822SKirill A. Shutemov * a page table. 961fc9fe822SKirill A. Shutemov */ 962fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 9635918d10aSKirill A. Shutemov struct page *zero_page; 96497ae1749SKirill A. Shutemov /* 96597ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 96697ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 96797ae1749SKirill A. Shutemov * reference. 96897ae1749SKirill A. Shutemov */ 9696fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(dst_mm); 9706b251fc9SAndrea Arcangeli set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, 9715918d10aSKirill A. Shutemov zero_page); 972fc9fe822SKirill A. Shutemov ret = 0; 973fc9fe822SKirill A. Shutemov goto out_unlock; 974fc9fe822SKirill A. Shutemov } 975de466bd6SMel Gorman 97671e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 977309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 97871e3aac0SAndrea Arcangeli get_page(src_page); 97953f9263bSKirill A. Shutemov page_dup_rmap(src_page, true); 98071e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 9815c7fb56eSDan Williams atomic_long_inc(&dst_mm->nr_ptes); 9825c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 98371e3aac0SAndrea Arcangeli 98471e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 98571e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 98671e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 98771e3aac0SAndrea Arcangeli 98871e3aac0SAndrea Arcangeli ret = 0; 98971e3aac0SAndrea Arcangeli out_unlock: 990c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 991c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 99271e3aac0SAndrea Arcangeli out: 99371e3aac0SAndrea Arcangeli return ret; 99471e3aac0SAndrea Arcangeli } 99571e3aac0SAndrea Arcangeli 996a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 997a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 998a00cc7d9SMatthew Wilcox pud_t *pud) 999a00cc7d9SMatthew Wilcox { 1000a00cc7d9SMatthew Wilcox pud_t _pud; 1001a00cc7d9SMatthew Wilcox 1002a00cc7d9SMatthew Wilcox /* 1003a00cc7d9SMatthew Wilcox * We should set the dirty bit only for FOLL_WRITE but for now 1004a00cc7d9SMatthew Wilcox * the dirty bit in the pud is meaningless. And if the dirty 1005a00cc7d9SMatthew Wilcox * bit will become meaningful and we'll only set it with 1006a00cc7d9SMatthew Wilcox * FOLL_WRITE, an atomic set_bit will be required on the pud to 1007a00cc7d9SMatthew Wilcox * set the young bit, instead of the current set_pud_at. 1008a00cc7d9SMatthew Wilcox */ 1009a00cc7d9SMatthew Wilcox _pud = pud_mkyoung(pud_mkdirty(*pud)); 1010a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 1011a00cc7d9SMatthew Wilcox pud, _pud, 1)) 1012a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1013a00cc7d9SMatthew Wilcox } 1014a00cc7d9SMatthew Wilcox 1015a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 1016a00cc7d9SMatthew Wilcox pud_t *pud, int flags) 1017a00cc7d9SMatthew Wilcox { 1018a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 1019a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1020a00cc7d9SMatthew Wilcox struct dev_pagemap *pgmap; 1021a00cc7d9SMatthew Wilcox struct page *page; 1022a00cc7d9SMatthew Wilcox 1023a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 1024a00cc7d9SMatthew Wilcox 1025a00cc7d9SMatthew Wilcox if (flags & FOLL_WRITE && !pud_write(*pud)) 1026a00cc7d9SMatthew Wilcox return NULL; 1027a00cc7d9SMatthew Wilcox 1028a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 1029a00cc7d9SMatthew Wilcox /* pass */; 1030a00cc7d9SMatthew Wilcox else 1031a00cc7d9SMatthew Wilcox return NULL; 1032a00cc7d9SMatthew Wilcox 1033a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 1034a00cc7d9SMatthew Wilcox touch_pud(vma, addr, pud); 1035a00cc7d9SMatthew Wilcox 1036a00cc7d9SMatthew Wilcox /* 1037a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 1038a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 1039a00cc7d9SMatthew Wilcox */ 1040a00cc7d9SMatthew Wilcox if (!(flags & FOLL_GET)) 1041a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 1042a00cc7d9SMatthew Wilcox 1043a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 1044a00cc7d9SMatthew Wilcox pgmap = get_dev_pagemap(pfn, NULL); 1045a00cc7d9SMatthew Wilcox if (!pgmap) 1046a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 1047a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 1048a00cc7d9SMatthew Wilcox get_page(page); 1049a00cc7d9SMatthew Wilcox put_dev_pagemap(pgmap); 1050a00cc7d9SMatthew Wilcox 1051a00cc7d9SMatthew Wilcox return page; 1052a00cc7d9SMatthew Wilcox } 1053a00cc7d9SMatthew Wilcox 1054a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1055a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1056a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1057a00cc7d9SMatthew Wilcox { 1058a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1059a00cc7d9SMatthew Wilcox pud_t pud; 1060a00cc7d9SMatthew Wilcox int ret; 1061a00cc7d9SMatthew Wilcox 1062a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1063a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1064a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1065a00cc7d9SMatthew Wilcox 1066a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1067a00cc7d9SMatthew Wilcox pud = *src_pud; 1068a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1069a00cc7d9SMatthew Wilcox goto out_unlock; 1070a00cc7d9SMatthew Wilcox 1071a00cc7d9SMatthew Wilcox /* 1072a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1073a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1074a00cc7d9SMatthew Wilcox * a page table. 1075a00cc7d9SMatthew Wilcox */ 1076a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1077a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1078a00cc7d9SMatthew Wilcox } 1079a00cc7d9SMatthew Wilcox 1080a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1081a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1082a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1083a00cc7d9SMatthew Wilcox 1084a00cc7d9SMatthew Wilcox ret = 0; 1085a00cc7d9SMatthew Wilcox out_unlock: 1086a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1087a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1088a00cc7d9SMatthew Wilcox return ret; 1089a00cc7d9SMatthew Wilcox } 1090a00cc7d9SMatthew Wilcox 1091a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1092a00cc7d9SMatthew Wilcox { 1093a00cc7d9SMatthew Wilcox pud_t entry; 1094a00cc7d9SMatthew Wilcox unsigned long haddr; 1095a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1096a00cc7d9SMatthew Wilcox 1097a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1098a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1099a00cc7d9SMatthew Wilcox goto unlock; 1100a00cc7d9SMatthew Wilcox 1101a00cc7d9SMatthew Wilcox entry = pud_mkyoung(orig_pud); 1102a00cc7d9SMatthew Wilcox if (write) 1103a00cc7d9SMatthew Wilcox entry = pud_mkdirty(entry); 1104a00cc7d9SMatthew Wilcox haddr = vmf->address & HPAGE_PUD_MASK; 1105a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) 1106a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); 1107a00cc7d9SMatthew Wilcox 1108a00cc7d9SMatthew Wilcox unlock: 1109a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1110a00cc7d9SMatthew Wilcox } 1111a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1112a00cc7d9SMatthew Wilcox 111382b0f8c3SJan Kara void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) 1114a1dd450bSWill Deacon { 1115a1dd450bSWill Deacon pmd_t entry; 1116a1dd450bSWill Deacon unsigned long haddr; 111720f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1118a1dd450bSWill Deacon 111982b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 112082b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 1121a1dd450bSWill Deacon goto unlock; 1122a1dd450bSWill Deacon 1123a1dd450bSWill Deacon entry = pmd_mkyoung(orig_pmd); 112420f664aaSMinchan Kim if (write) 112520f664aaSMinchan Kim entry = pmd_mkdirty(entry); 112682b0f8c3SJan Kara haddr = vmf->address & HPAGE_PMD_MASK; 112720f664aaSMinchan Kim if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) 112882b0f8c3SJan Kara update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); 1129a1dd450bSWill Deacon 1130a1dd450bSWill Deacon unlock: 113182b0f8c3SJan Kara spin_unlock(vmf->ptl); 1132a1dd450bSWill Deacon } 1133a1dd450bSWill Deacon 113482b0f8c3SJan Kara static int do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, pmd_t orig_pmd, 1135bae473a4SKirill A. Shutemov struct page *page) 113671e3aac0SAndrea Arcangeli { 113782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 113882b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 113900501b53SJohannes Weiner struct mem_cgroup *memcg; 114071e3aac0SAndrea Arcangeli pgtable_t pgtable; 114171e3aac0SAndrea Arcangeli pmd_t _pmd; 114271e3aac0SAndrea Arcangeli int ret = 0, i; 114371e3aac0SAndrea Arcangeli struct page **pages; 11442ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 11452ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 114671e3aac0SAndrea Arcangeli 114771e3aac0SAndrea Arcangeli pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, 114871e3aac0SAndrea Arcangeli GFP_KERNEL); 114971e3aac0SAndrea Arcangeli if (unlikely(!pages)) { 115071e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 115171e3aac0SAndrea Arcangeli goto out; 115271e3aac0SAndrea Arcangeli } 115371e3aac0SAndrea Arcangeli 115471e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 115541b6167eSMichal Hocko pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, 115682b0f8c3SJan Kara vmf->address, page_to_nid(page)); 1157b9bbfbe3SAndrea Arcangeli if (unlikely(!pages[i] || 1158bae473a4SKirill A. Shutemov mem_cgroup_try_charge(pages[i], vma->vm_mm, 1159bae473a4SKirill A. Shutemov GFP_KERNEL, &memcg, false))) { 1160b9bbfbe3SAndrea Arcangeli if (pages[i]) 116171e3aac0SAndrea Arcangeli put_page(pages[i]); 1162b9bbfbe3SAndrea Arcangeli while (--i >= 0) { 116300501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 116400501b53SJohannes Weiner set_page_private(pages[i], 0); 1165f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(pages[i], memcg, 1166f627c2f5SKirill A. Shutemov false); 1167b9bbfbe3SAndrea Arcangeli put_page(pages[i]); 1168b9bbfbe3SAndrea Arcangeli } 116971e3aac0SAndrea Arcangeli kfree(pages); 117071e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 117171e3aac0SAndrea Arcangeli goto out; 117271e3aac0SAndrea Arcangeli } 117300501b53SJohannes Weiner set_page_private(pages[i], (unsigned long)memcg); 117471e3aac0SAndrea Arcangeli } 117571e3aac0SAndrea Arcangeli 117671e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 117771e3aac0SAndrea Arcangeli copy_user_highpage(pages[i], page + i, 11780089e485SHillf Danton haddr + PAGE_SIZE * i, vma); 117971e3aac0SAndrea Arcangeli __SetPageUptodate(pages[i]); 118071e3aac0SAndrea Arcangeli cond_resched(); 118171e3aac0SAndrea Arcangeli } 118271e3aac0SAndrea Arcangeli 11832ec74c3eSSagi Grimberg mmun_start = haddr; 11842ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 1185bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); 11862ec74c3eSSagi Grimberg 118782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 118882b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 118971e3aac0SAndrea Arcangeli goto out_free_pages; 1190309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 119171e3aac0SAndrea Arcangeli 119282b0f8c3SJan Kara pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); 119371e3aac0SAndrea Arcangeli /* leave pmd empty until pte is filled */ 119471e3aac0SAndrea Arcangeli 119582b0f8c3SJan Kara pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); 1196bae473a4SKirill A. Shutemov pmd_populate(vma->vm_mm, &_pmd, pgtable); 119771e3aac0SAndrea Arcangeli 119871e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 1199bae473a4SKirill A. Shutemov pte_t entry; 120071e3aac0SAndrea Arcangeli entry = mk_pte(pages[i], vma->vm_page_prot); 120171e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 120200501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 120300501b53SJohannes Weiner set_page_private(pages[i], 0); 120482b0f8c3SJan Kara page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); 1205f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(pages[i], memcg, false, false); 120600501b53SJohannes Weiner lru_cache_add_active_or_unevictable(pages[i], vma); 120782b0f8c3SJan Kara vmf->pte = pte_offset_map(&_pmd, haddr); 120882b0f8c3SJan Kara VM_BUG_ON(!pte_none(*vmf->pte)); 120982b0f8c3SJan Kara set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); 121082b0f8c3SJan Kara pte_unmap(vmf->pte); 121171e3aac0SAndrea Arcangeli } 121271e3aac0SAndrea Arcangeli kfree(pages); 121371e3aac0SAndrea Arcangeli 121471e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 121582b0f8c3SJan Kara pmd_populate(vma->vm_mm, vmf->pmd, pgtable); 1216d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 121782b0f8c3SJan Kara spin_unlock(vmf->ptl); 121871e3aac0SAndrea Arcangeli 1219bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); 12202ec74c3eSSagi Grimberg 122171e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 122271e3aac0SAndrea Arcangeli put_page(page); 122371e3aac0SAndrea Arcangeli 122471e3aac0SAndrea Arcangeli out: 122571e3aac0SAndrea Arcangeli return ret; 122671e3aac0SAndrea Arcangeli 122771e3aac0SAndrea Arcangeli out_free_pages: 122882b0f8c3SJan Kara spin_unlock(vmf->ptl); 1229bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); 1230b9bbfbe3SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 123100501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 123200501b53SJohannes Weiner set_page_private(pages[i], 0); 1233f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(pages[i], memcg, false); 123471e3aac0SAndrea Arcangeli put_page(pages[i]); 1235b9bbfbe3SAndrea Arcangeli } 123671e3aac0SAndrea Arcangeli kfree(pages); 123771e3aac0SAndrea Arcangeli goto out; 123871e3aac0SAndrea Arcangeli } 123971e3aac0SAndrea Arcangeli 124082b0f8c3SJan Kara int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) 124171e3aac0SAndrea Arcangeli { 124282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 124393b4796dSKirill A. Shutemov struct page *page = NULL, *new_page; 124400501b53SJohannes Weiner struct mem_cgroup *memcg; 124582b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 12462ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 12472ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 12483b363692SMichal Hocko gfp_t huge_gfp; /* for allocation and charge */ 1249bae473a4SKirill A. Shutemov int ret = 0; 125071e3aac0SAndrea Arcangeli 125182b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 125281d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 125393b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 125493b4796dSKirill A. Shutemov goto alloc; 125582b0f8c3SJan Kara spin_lock(vmf->ptl); 125682b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 125771e3aac0SAndrea Arcangeli goto out_unlock; 125871e3aac0SAndrea Arcangeli 125971e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 1260309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); 12611f25fe20SKirill A. Shutemov /* 12621f25fe20SKirill A. Shutemov * We can only reuse the page if nobody else maps the huge page or it's 12636d0a07edSAndrea Arcangeli * part. 12641f25fe20SKirill A. Shutemov */ 1265ba3c4ce6SHuang Ying if (!trylock_page(page)) { 1266ba3c4ce6SHuang Ying get_page(page); 1267ba3c4ce6SHuang Ying spin_unlock(vmf->ptl); 1268ba3c4ce6SHuang Ying lock_page(page); 1269ba3c4ce6SHuang Ying spin_lock(vmf->ptl); 1270ba3c4ce6SHuang Ying if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 1271ba3c4ce6SHuang Ying unlock_page(page); 1272ba3c4ce6SHuang Ying put_page(page); 1273ba3c4ce6SHuang Ying goto out_unlock; 1274ba3c4ce6SHuang Ying } 1275ba3c4ce6SHuang Ying put_page(page); 1276ba3c4ce6SHuang Ying } 1277ba3c4ce6SHuang Ying if (reuse_swap_page(page, NULL)) { 127871e3aac0SAndrea Arcangeli pmd_t entry; 127971e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 128071e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 128182b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 128282b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 128371e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 1284ba3c4ce6SHuang Ying unlock_page(page); 128571e3aac0SAndrea Arcangeli goto out_unlock; 128671e3aac0SAndrea Arcangeli } 1287ba3c4ce6SHuang Ying unlock_page(page); 1288ddc58f27SKirill A. Shutemov get_page(page); 128982b0f8c3SJan Kara spin_unlock(vmf->ptl); 129093b4796dSKirill A. Shutemov alloc: 129171e3aac0SAndrea Arcangeli if (transparent_hugepage_enabled(vma) && 1292077fcf11SAneesh Kumar K.V !transparent_hugepage_debug_cow()) { 1293444eb2a4SMel Gorman huge_gfp = alloc_hugepage_direct_gfpmask(vma); 12943b363692SMichal Hocko new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); 1295077fcf11SAneesh Kumar K.V } else 129671e3aac0SAndrea Arcangeli new_page = NULL; 129771e3aac0SAndrea Arcangeli 12989a982250SKirill A. Shutemov if (likely(new_page)) { 12999a982250SKirill A. Shutemov prep_transhuge_page(new_page); 13009a982250SKirill A. Shutemov } else { 1301eecc1e42SHugh Dickins if (!page) { 130282b0f8c3SJan Kara split_huge_pmd(vma, vmf->pmd, vmf->address); 1303e9b71ca9SKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 130493b4796dSKirill A. Shutemov } else { 130582b0f8c3SJan Kara ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); 13069845cbbdSKirill A. Shutemov if (ret & VM_FAULT_OOM) { 130782b0f8c3SJan Kara split_huge_pmd(vma, vmf->pmd, vmf->address); 13089845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 13099845cbbdSKirill A. Shutemov } 1310ddc58f27SKirill A. Shutemov put_page(page); 131193b4796dSKirill A. Shutemov } 131217766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 131371e3aac0SAndrea Arcangeli goto out; 131471e3aac0SAndrea Arcangeli } 131571e3aac0SAndrea Arcangeli 1316bae473a4SKirill A. Shutemov if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm, 1317bae473a4SKirill A. Shutemov huge_gfp, &memcg, true))) { 1318b9bbfbe3SAndrea Arcangeli put_page(new_page); 131982b0f8c3SJan Kara split_huge_pmd(vma, vmf->pmd, vmf->address); 1320bae473a4SKirill A. Shutemov if (page) 1321ddc58f27SKirill A. Shutemov put_page(page); 13229845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 132317766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 1324b9bbfbe3SAndrea Arcangeli goto out; 1325b9bbfbe3SAndrea Arcangeli } 1326b9bbfbe3SAndrea Arcangeli 132717766ddeSDavid Rientjes count_vm_event(THP_FAULT_ALLOC); 132817766ddeSDavid Rientjes 1329eecc1e42SHugh Dickins if (!page) 1330c79b57e4SHuang Ying clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR); 133193b4796dSKirill A. Shutemov else 133271e3aac0SAndrea Arcangeli copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); 133371e3aac0SAndrea Arcangeli __SetPageUptodate(new_page); 133471e3aac0SAndrea Arcangeli 13352ec74c3eSSagi Grimberg mmun_start = haddr; 13362ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 1337bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); 13382ec74c3eSSagi Grimberg 133982b0f8c3SJan Kara spin_lock(vmf->ptl); 134093b4796dSKirill A. Shutemov if (page) 1341ddc58f27SKirill A. Shutemov put_page(page); 134282b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 134382b0f8c3SJan Kara spin_unlock(vmf->ptl); 1344f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(new_page, memcg, true); 134571e3aac0SAndrea Arcangeli put_page(new_page); 13462ec74c3eSSagi Grimberg goto out_mn; 1347b9bbfbe3SAndrea Arcangeli } else { 134871e3aac0SAndrea Arcangeli pmd_t entry; 13493122359aSKirill A. Shutemov entry = mk_huge_pmd(new_page, vma->vm_page_prot); 13503122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 135182b0f8c3SJan Kara pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); 1352d281ee61SKirill A. Shutemov page_add_new_anon_rmap(new_page, vma, haddr, true); 1353f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(new_page, memcg, false, true); 135400501b53SJohannes Weiner lru_cache_add_active_or_unevictable(new_page, vma); 135582b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 135682b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1357eecc1e42SHugh Dickins if (!page) { 1358bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 135997ae1749SKirill A. Shutemov } else { 1360309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1361d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 136271e3aac0SAndrea Arcangeli put_page(page); 136393b4796dSKirill A. Shutemov } 136471e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 136571e3aac0SAndrea Arcangeli } 136682b0f8c3SJan Kara spin_unlock(vmf->ptl); 13672ec74c3eSSagi Grimberg out_mn: 1368bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); 13692ec74c3eSSagi Grimberg out: 13702ec74c3eSSagi Grimberg return ret; 137171e3aac0SAndrea Arcangeli out_unlock: 137282b0f8c3SJan Kara spin_unlock(vmf->ptl); 137371e3aac0SAndrea Arcangeli return ret; 137471e3aac0SAndrea Arcangeli } 137571e3aac0SAndrea Arcangeli 13768310d48bSKeno Fischer /* 13778310d48bSKeno Fischer * FOLL_FORCE can write to even unwritable pmd's, but only 13788310d48bSKeno Fischer * after we've gone through a COW cycle and they are dirty. 13798310d48bSKeno Fischer */ 13808310d48bSKeno Fischer static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) 13818310d48bSKeno Fischer { 13828310d48bSKeno Fischer return pmd_write(pmd) || 13838310d48bSKeno Fischer ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); 13848310d48bSKeno Fischer } 13858310d48bSKeno Fischer 1386b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 138771e3aac0SAndrea Arcangeli unsigned long addr, 138871e3aac0SAndrea Arcangeli pmd_t *pmd, 138971e3aac0SAndrea Arcangeli unsigned int flags) 139071e3aac0SAndrea Arcangeli { 1391b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 139271e3aac0SAndrea Arcangeli struct page *page = NULL; 139371e3aac0SAndrea Arcangeli 1394c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 139571e3aac0SAndrea Arcangeli 13968310d48bSKeno Fischer if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) 139771e3aac0SAndrea Arcangeli goto out; 139871e3aac0SAndrea Arcangeli 139985facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 140085facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 140185facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 140285facf25SKirill A. Shutemov 14032b4847e7SMel Gorman /* Full NUMA hinting faults to serialise migration in fault paths */ 14048a0516edSMel Gorman if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) 14052b4847e7SMel Gorman goto out; 14062b4847e7SMel Gorman 140771e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 1408ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 14093565fce3SDan Williams if (flags & FOLL_TOUCH) 14103565fce3SDan Williams touch_pmd(vma, addr, pmd); 1411de60f5f1SEric B Munson if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { 1412e90309c9SKirill A. Shutemov /* 1413e90309c9SKirill A. Shutemov * We don't mlock() pte-mapped THPs. This way we can avoid 1414e90309c9SKirill A. Shutemov * leaking mlocked pages into non-VM_LOCKED VMAs. 1415e90309c9SKirill A. Shutemov * 14169a73f61bSKirill A. Shutemov * For anon THP: 14179a73f61bSKirill A. Shutemov * 1418e90309c9SKirill A. Shutemov * In most cases the pmd is the only mapping of the page as we 1419e90309c9SKirill A. Shutemov * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for 1420e90309c9SKirill A. Shutemov * writable private mappings in populate_vma_page_range(). 1421e90309c9SKirill A. Shutemov * 1422e90309c9SKirill A. Shutemov * The only scenario when we have the page shared here is if we 1423e90309c9SKirill A. Shutemov * mlocking read-only mapping shared over fork(). We skip 1424e90309c9SKirill A. Shutemov * mlocking such pages. 14259a73f61bSKirill A. Shutemov * 14269a73f61bSKirill A. Shutemov * For file THP: 14279a73f61bSKirill A. Shutemov * 14289a73f61bSKirill A. Shutemov * We can expect PageDoubleMap() to be stable under page lock: 14299a73f61bSKirill A. Shutemov * for file pages we set it in page_add_file_rmap(), which 14309a73f61bSKirill A. Shutemov * requires page to be locked. 1431e90309c9SKirill A. Shutemov */ 14329a73f61bSKirill A. Shutemov 14339a73f61bSKirill A. Shutemov if (PageAnon(page) && compound_mapcount(page) != 1) 14349a73f61bSKirill A. Shutemov goto skip_mlock; 14359a73f61bSKirill A. Shutemov if (PageDoubleMap(page) || !page->mapping) 14369a73f61bSKirill A. Shutemov goto skip_mlock; 14379a73f61bSKirill A. Shutemov if (!trylock_page(page)) 14389a73f61bSKirill A. Shutemov goto skip_mlock; 1439b676b293SDavid Rientjes lru_add_drain(); 14409a73f61bSKirill A. Shutemov if (page->mapping && !PageDoubleMap(page)) 1441b676b293SDavid Rientjes mlock_vma_page(page); 1442b676b293SDavid Rientjes unlock_page(page); 1443b676b293SDavid Rientjes } 14449a73f61bSKirill A. Shutemov skip_mlock: 144571e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1446ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 144771e3aac0SAndrea Arcangeli if (flags & FOLL_GET) 1448ddc58f27SKirill A. Shutemov get_page(page); 144971e3aac0SAndrea Arcangeli 145071e3aac0SAndrea Arcangeli out: 145171e3aac0SAndrea Arcangeli return page; 145271e3aac0SAndrea Arcangeli } 145371e3aac0SAndrea Arcangeli 1454d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 145582b0f8c3SJan Kara int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) 1456d10e63f2SMel Gorman { 145782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1458b8916634SMel Gorman struct anon_vma *anon_vma = NULL; 1459b32967ffSMel Gorman struct page *page; 146082b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 14618191acbdSMel Gorman int page_nid = -1, this_nid = numa_node_id(); 146290572890SPeter Zijlstra int target_nid, last_cpupid = -1; 14638191acbdSMel Gorman bool page_locked; 14648191acbdSMel Gorman bool migrated = false; 1465b191f9b1SMel Gorman bool was_writable; 14666688cc05SPeter Zijlstra int flags = 0; 1467d10e63f2SMel Gorman 146882b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 146982b0f8c3SJan Kara if (unlikely(!pmd_same(pmd, *vmf->pmd))) 1470d10e63f2SMel Gorman goto out_unlock; 1471d10e63f2SMel Gorman 1472de466bd6SMel Gorman /* 1473de466bd6SMel Gorman * If there are potential migrations, wait for completion and retry 1474de466bd6SMel Gorman * without disrupting NUMA hinting information. Do not relock and 1475de466bd6SMel Gorman * check_same as the page may no longer be mapped. 1476de466bd6SMel Gorman */ 147782b0f8c3SJan Kara if (unlikely(pmd_trans_migrating(*vmf->pmd))) { 147882b0f8c3SJan Kara page = pmd_page(*vmf->pmd); 14793c226c63SMark Rutland if (!get_page_unless_zero(page)) 14803c226c63SMark Rutland goto out_unlock; 148182b0f8c3SJan Kara spin_unlock(vmf->ptl); 14825d833062SMel Gorman wait_on_page_locked(page); 14833c226c63SMark Rutland put_page(page); 1484de466bd6SMel Gorman goto out; 1485de466bd6SMel Gorman } 1486de466bd6SMel Gorman 1487d10e63f2SMel Gorman page = pmd_page(pmd); 1488a1a46184SMel Gorman BUG_ON(is_huge_zero_page(page)); 14898191acbdSMel Gorman page_nid = page_to_nid(page); 149090572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 149103c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 149204bb2f94SRik van Riel if (page_nid == this_nid) { 149303c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 149404bb2f94SRik van Riel flags |= TNF_FAULT_LOCAL; 149504bb2f94SRik van Riel } 14964daae3b4SMel Gorman 1497bea66fbdSMel Gorman /* See similar comment in do_numa_page for explanation */ 1498288bc549SAneesh Kumar K.V if (!pmd_savedwrite(pmd)) 14996688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 15006688cc05SPeter Zijlstra 15016688cc05SPeter Zijlstra /* 1502ff9042b1SMel Gorman * Acquire the page lock to serialise THP migrations but avoid dropping 1503ff9042b1SMel Gorman * page_table_lock if at all possible 1504ff9042b1SMel Gorman */ 1505b8916634SMel Gorman page_locked = trylock_page(page); 1506b8916634SMel Gorman target_nid = mpol_misplaced(page, vma, haddr); 1507b8916634SMel Gorman if (target_nid == -1) { 1508b8916634SMel Gorman /* If the page was locked, there are no parallel migrations */ 1509a54a407fSMel Gorman if (page_locked) 1510b8916634SMel Gorman goto clear_pmdnuma; 15112b4847e7SMel Gorman } 1512cbee9f88SPeter Zijlstra 1513de466bd6SMel Gorman /* Migration could have started since the pmd_trans_migrating check */ 15142b4847e7SMel Gorman if (!page_locked) { 15153c226c63SMark Rutland page_nid = -1; 15163c226c63SMark Rutland if (!get_page_unless_zero(page)) 15173c226c63SMark Rutland goto out_unlock; 151882b0f8c3SJan Kara spin_unlock(vmf->ptl); 1519b8916634SMel Gorman wait_on_page_locked(page); 15203c226c63SMark Rutland put_page(page); 1521b8916634SMel Gorman goto out; 1522b8916634SMel Gorman } 1523b8916634SMel Gorman 15242b4847e7SMel Gorman /* 15252b4847e7SMel Gorman * Page is misplaced. Page lock serialises migrations. Acquire anon_vma 15262b4847e7SMel Gorman * to serialises splits 15272b4847e7SMel Gorman */ 1528b8916634SMel Gorman get_page(page); 152982b0f8c3SJan Kara spin_unlock(vmf->ptl); 1530b8916634SMel Gorman anon_vma = page_lock_anon_vma_read(page); 1531b32967ffSMel Gorman 1532c69307d5SPeter Zijlstra /* Confirm the PMD did not change while page_table_lock was released */ 153382b0f8c3SJan Kara spin_lock(vmf->ptl); 153482b0f8c3SJan Kara if (unlikely(!pmd_same(pmd, *vmf->pmd))) { 1535b32967ffSMel Gorman unlock_page(page); 1536b32967ffSMel Gorman put_page(page); 1537a54a407fSMel Gorman page_nid = -1; 1538b32967ffSMel Gorman goto out_unlock; 1539b32967ffSMel Gorman } 1540ff9042b1SMel Gorman 1541c3a489caSMel Gorman /* Bail if we fail to protect against THP splits for any reason */ 1542c3a489caSMel Gorman if (unlikely(!anon_vma)) { 1543c3a489caSMel Gorman put_page(page); 1544c3a489caSMel Gorman page_nid = -1; 1545c3a489caSMel Gorman goto clear_pmdnuma; 1546c3a489caSMel Gorman } 1547c3a489caSMel Gorman 1548a54a407fSMel Gorman /* 15498b1b436dSPeter Zijlstra * Since we took the NUMA fault, we must have observed the !accessible 15508b1b436dSPeter Zijlstra * bit. Make sure all other CPUs agree with that, to avoid them 15518b1b436dSPeter Zijlstra * modifying the page we're about to migrate. 15528b1b436dSPeter Zijlstra * 15538b1b436dSPeter Zijlstra * Must be done under PTL such that we'll observe the relevant 1554ccde85baSPeter Zijlstra * inc_tlb_flush_pending(). 1555ccde85baSPeter Zijlstra * 1556ccde85baSPeter Zijlstra * We are not sure a pending tlb flush here is for a huge page 1557ccde85baSPeter Zijlstra * mapping or not. Hence use the tlb range variant 15588b1b436dSPeter Zijlstra */ 15598b1b436dSPeter Zijlstra if (mm_tlb_flush_pending(vma->vm_mm)) 1560ccde85baSPeter Zijlstra flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); 15618b1b436dSPeter Zijlstra 15628b1b436dSPeter Zijlstra /* 1563a54a407fSMel Gorman * Migrate the THP to the requested node, returns with page unlocked 15648a0516edSMel Gorman * and access rights restored. 1565a54a407fSMel Gorman */ 156682b0f8c3SJan Kara spin_unlock(vmf->ptl); 15678b1b436dSPeter Zijlstra 1568bae473a4SKirill A. Shutemov migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, 156982b0f8c3SJan Kara vmf->pmd, pmd, vmf->address, page, target_nid); 15706688cc05SPeter Zijlstra if (migrated) { 15716688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 15728191acbdSMel Gorman page_nid = target_nid; 1573074c2381SMel Gorman } else 1574074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1575b32967ffSMel Gorman 15768191acbdSMel Gorman goto out; 15774daae3b4SMel Gorman clear_pmdnuma: 1578a54a407fSMel Gorman BUG_ON(!PageLocked(page)); 1579288bc549SAneesh Kumar K.V was_writable = pmd_savedwrite(pmd); 15804d942466SMel Gorman pmd = pmd_modify(pmd, vma->vm_page_prot); 1581b7b04004SMel Gorman pmd = pmd_mkyoung(pmd); 1582b191f9b1SMel Gorman if (was_writable) 1583b191f9b1SMel Gorman pmd = pmd_mkwrite(pmd); 158482b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 158582b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1586a54a407fSMel Gorman unlock_page(page); 1587d10e63f2SMel Gorman out_unlock: 158882b0f8c3SJan Kara spin_unlock(vmf->ptl); 1589b8916634SMel Gorman 1590b8916634SMel Gorman out: 1591b8916634SMel Gorman if (anon_vma) 1592b8916634SMel Gorman page_unlock_anon_vma_read(anon_vma); 1593b8916634SMel Gorman 15948191acbdSMel Gorman if (page_nid != -1) 159582b0f8c3SJan Kara task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, 15969a8b300fSAneesh Kumar K.V flags); 15978191acbdSMel Gorman 1598d10e63f2SMel Gorman return 0; 1599d10e63f2SMel Gorman } 1600d10e63f2SMel Gorman 1601319904adSHuang Ying /* 1602319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1603319904adSHuang Ying * Otherwise, return false. 1604319904adSHuang Ying */ 1605319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1606b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1607b8d3c4c3SMinchan Kim { 1608b8d3c4c3SMinchan Kim spinlock_t *ptl; 1609b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1610b8d3c4c3SMinchan Kim struct page *page; 1611b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1612319904adSHuang Ying bool ret = false; 1613b8d3c4c3SMinchan Kim 161407e32661SAneesh Kumar K.V tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); 161507e32661SAneesh Kumar K.V 1616b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1617b6ec57f4SKirill A. Shutemov if (!ptl) 161825eedabeSLinus Torvalds goto out_unlocked; 1619b8d3c4c3SMinchan Kim 1620b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1621319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1622b8d3c4c3SMinchan Kim goto out; 1623b8d3c4c3SMinchan Kim 162484c3fc4eSZi Yan if (unlikely(!pmd_present(orig_pmd))) { 162584c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 162684c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 162784c3fc4eSZi Yan goto out; 162884c3fc4eSZi Yan } 162984c3fc4eSZi Yan 1630b8d3c4c3SMinchan Kim page = pmd_page(orig_pmd); 1631b8d3c4c3SMinchan Kim /* 1632b8d3c4c3SMinchan Kim * If other processes are mapping this page, we couldn't discard 1633b8d3c4c3SMinchan Kim * the page unless they all do MADV_FREE so let's skip the page. 1634b8d3c4c3SMinchan Kim */ 1635b8d3c4c3SMinchan Kim if (page_mapcount(page) != 1) 1636b8d3c4c3SMinchan Kim goto out; 1637b8d3c4c3SMinchan Kim 1638b8d3c4c3SMinchan Kim if (!trylock_page(page)) 1639b8d3c4c3SMinchan Kim goto out; 1640b8d3c4c3SMinchan Kim 1641b8d3c4c3SMinchan Kim /* 1642b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1643b8d3c4c3SMinchan Kim * will deactivate only them. 1644b8d3c4c3SMinchan Kim */ 1645b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1646b8d3c4c3SMinchan Kim get_page(page); 1647b8d3c4c3SMinchan Kim spin_unlock(ptl); 16489818b8cdSHuang Ying split_huge_page(page); 1649b8d3c4c3SMinchan Kim unlock_page(page); 1650bbf29ffcSKirill A. Shutemov put_page(page); 1651b8d3c4c3SMinchan Kim goto out_unlocked; 1652b8d3c4c3SMinchan Kim } 1653b8d3c4c3SMinchan Kim 1654b8d3c4c3SMinchan Kim if (PageDirty(page)) 1655b8d3c4c3SMinchan Kim ClearPageDirty(page); 1656b8d3c4c3SMinchan Kim unlock_page(page); 1657b8d3c4c3SMinchan Kim 1658b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 165958ceeb6bSKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1660b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1661b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1662b8d3c4c3SMinchan Kim 1663b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1664b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1665b8d3c4c3SMinchan Kim } 1666802a3a92SShaohua Li 1667802a3a92SShaohua Li mark_page_lazyfree(page); 1668319904adSHuang Ying ret = true; 1669b8d3c4c3SMinchan Kim out: 1670b8d3c4c3SMinchan Kim spin_unlock(ptl); 1671b8d3c4c3SMinchan Kim out_unlocked: 1672b8d3c4c3SMinchan Kim return ret; 1673b8d3c4c3SMinchan Kim } 1674b8d3c4c3SMinchan Kim 1675953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1676953c66c2SAneesh Kumar K.V { 1677953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1678953c66c2SAneesh Kumar K.V 1679953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1680953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1681953c66c2SAneesh Kumar K.V atomic_long_dec(&mm->nr_ptes); 1682953c66c2SAneesh Kumar K.V } 1683953c66c2SAneesh Kumar K.V 168471e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1685f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 168671e3aac0SAndrea Arcangeli { 1687f5c8ad47SDavid Miller pmd_t orig_pmd; 1688da146769SKirill A. Shutemov spinlock_t *ptl; 1689da146769SKirill A. Shutemov 169007e32661SAneesh Kumar K.V tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); 169107e32661SAneesh Kumar K.V 1692b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1693b6ec57f4SKirill A. Shutemov if (!ptl) 1694da146769SKirill A. Shutemov return 0; 1695a6bf2bb0SAneesh Kumar K.V /* 1696a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 16978809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1698a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1699a6bf2bb0SAneesh Kumar K.V * operations. 1700a6bf2bb0SAneesh Kumar K.V */ 17018809aa2dSAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, 1702fcbe08d6SMartin Schwidefsky tlb->fullmm); 1703f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 17044897c765SMatthew Wilcox if (vma_is_dax(vma)) { 17053b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) 17063b6521f5SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 17074897c765SMatthew Wilcox spin_unlock(ptl); 1708da146769SKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 1709c0f2e176SAneesh Kumar K.V tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); 1710da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1711c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1712bf929152SKirill A. Shutemov spin_unlock(ptl); 1713c0f2e176SAneesh Kumar K.V tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); 1714479f0abbSKirill A. Shutemov } else { 1715616b8371SZi Yan struct page *page = NULL; 1716616b8371SZi Yan int flush_needed = 1; 1717616b8371SZi Yan 1718616b8371SZi Yan if (pmd_present(orig_pmd)) { 1719616b8371SZi Yan page = pmd_page(orig_pmd); 1720d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 1721309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1722309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1723616b8371SZi Yan } else if (thp_migration_supported()) { 1724616b8371SZi Yan swp_entry_t entry; 1725616b8371SZi Yan 1726616b8371SZi Yan VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); 1727616b8371SZi Yan entry = pmd_to_swp_entry(orig_pmd); 1728616b8371SZi Yan page = pfn_to_page(swp_offset(entry)); 1729616b8371SZi Yan flush_needed = 0; 1730616b8371SZi Yan } else 1731616b8371SZi Yan WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); 1732616b8371SZi Yan 1733b5072380SKirill A. Shutemov if (PageAnon(page)) { 1734c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1735b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1736b5072380SKirill A. Shutemov } else { 1737953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1738953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1739b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR); 1740b5072380SKirill A. Shutemov } 1741616b8371SZi Yan 1742bf929152SKirill A. Shutemov spin_unlock(ptl); 1743616b8371SZi Yan if (flush_needed) 1744e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1745479f0abbSKirill A. Shutemov } 1746da146769SKirill A. Shutemov return 1; 174771e3aac0SAndrea Arcangeli } 174871e3aac0SAndrea Arcangeli 17491dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 17501dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 17511dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 17521dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 17531dd38b6cSAneesh Kumar K.V { 17541dd38b6cSAneesh Kumar K.V /* 17551dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 17561dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 17571dd38b6cSAneesh Kumar K.V * 17581dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 17591dd38b6cSAneesh Kumar K.V */ 17601dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 17611dd38b6cSAneesh Kumar K.V } 17621dd38b6cSAneesh Kumar K.V #endif 17631dd38b6cSAneesh Kumar K.V 1764ab6e3d09SNaoya Horiguchi static pmd_t move_soft_dirty_pmd(pmd_t pmd) 1765ab6e3d09SNaoya Horiguchi { 1766ab6e3d09SNaoya Horiguchi #ifdef CONFIG_MEM_SOFT_DIRTY 1767ab6e3d09SNaoya Horiguchi if (unlikely(is_pmd_migration_entry(pmd))) 1768ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 1769ab6e3d09SNaoya Horiguchi else if (pmd_present(pmd)) 1770ab6e3d09SNaoya Horiguchi pmd = pmd_mksoft_dirty(pmd); 1771ab6e3d09SNaoya Horiguchi #endif 1772ab6e3d09SNaoya Horiguchi return pmd; 1773ab6e3d09SNaoya Horiguchi } 1774ab6e3d09SNaoya Horiguchi 1775bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 177637a1c49aSAndrea Arcangeli unsigned long new_addr, unsigned long old_end, 17775d190420SAaron Lu pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush) 177837a1c49aSAndrea Arcangeli { 1779bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 178037a1c49aSAndrea Arcangeli pmd_t pmd; 178137a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 17825d190420SAaron Lu bool force_flush = false; 178337a1c49aSAndrea Arcangeli 178437a1c49aSAndrea Arcangeli if ((old_addr & ~HPAGE_PMD_MASK) || 178537a1c49aSAndrea Arcangeli (new_addr & ~HPAGE_PMD_MASK) || 1786bf8616d5SHugh Dickins old_end - old_addr < HPAGE_PMD_SIZE) 17874b471e88SKirill A. Shutemov return false; 178837a1c49aSAndrea Arcangeli 178937a1c49aSAndrea Arcangeli /* 179037a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 179137a1c49aSAndrea Arcangeli * should have release it. 179237a1c49aSAndrea Arcangeli */ 179337a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 179437a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 17954b471e88SKirill A. Shutemov return false; 179637a1c49aSAndrea Arcangeli } 179737a1c49aSAndrea Arcangeli 1798bf929152SKirill A. Shutemov /* 1799bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1800bf929152SKirill A. Shutemov * ptlocks because exclusive mmap_sem prevents deadlock. 1801bf929152SKirill A. Shutemov */ 1802b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1803b6ec57f4SKirill A. Shutemov if (old_ptl) { 1804bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1805bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1806bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 18078809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1808a2ce2666SAaron Lu if (pmd_present(pmd) && pmd_dirty(pmd)) 1809a2ce2666SAaron Lu force_flush = true; 181037a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 18113592806cSKirill A. Shutemov 18121dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1813b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 18143592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 18153592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 18163592806cSKirill A. Shutemov } 1817ab6e3d09SNaoya Horiguchi pmd = move_soft_dirty_pmd(pmd); 1818ab6e3d09SNaoya Horiguchi set_pmd_at(mm, new_addr, new_pmd, pmd); 1819b3084f4dSAneesh Kumar K.V if (new_ptl != old_ptl) 1820b3084f4dSAneesh Kumar K.V spin_unlock(new_ptl); 18215d190420SAaron Lu if (force_flush) 18225d190420SAaron Lu flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 18235d190420SAaron Lu else 18245d190420SAaron Lu *need_flush = true; 1825bf929152SKirill A. Shutemov spin_unlock(old_ptl); 18264b471e88SKirill A. Shutemov return true; 182737a1c49aSAndrea Arcangeli } 18284b471e88SKirill A. Shutemov return false; 182937a1c49aSAndrea Arcangeli } 183037a1c49aSAndrea Arcangeli 1831f123d74aSMel Gorman /* 1832f123d74aSMel Gorman * Returns 1833f123d74aSMel Gorman * - 0 if PMD could not be locked 1834f123d74aSMel Gorman * - 1 if PMD was locked but protections unchange and TLB flush unnecessary 1835f123d74aSMel Gorman * - HPAGE_PMD_NR is protections changed and TLB flush necessary 1836f123d74aSMel Gorman */ 1837cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 1838e944fd67SMel Gorman unsigned long addr, pgprot_t newprot, int prot_numa) 1839cd7548abSJohannes Weiner { 1840cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1841bf929152SKirill A. Shutemov spinlock_t *ptl; 18420a85e51dSKirill A. Shutemov pmd_t entry; 18430a85e51dSKirill A. Shutemov bool preserve_write; 18440a85e51dSKirill A. Shutemov int ret; 1845cd7548abSJohannes Weiner 1846b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 18470a85e51dSKirill A. Shutemov if (!ptl) 18480a85e51dSKirill A. Shutemov return 0; 18490a85e51dSKirill A. Shutemov 18500a85e51dSKirill A. Shutemov preserve_write = prot_numa && pmd_write(*pmd); 1851ba68bc01SMel Gorman ret = 1; 1852e944fd67SMel Gorman 185384c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 185484c3fc4eSZi Yan if (is_swap_pmd(*pmd)) { 185584c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(*pmd); 185684c3fc4eSZi Yan 185784c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd)); 185884c3fc4eSZi Yan if (is_write_migration_entry(entry)) { 185984c3fc4eSZi Yan pmd_t newpmd; 186084c3fc4eSZi Yan /* 186184c3fc4eSZi Yan * A protection check is difficult so 186284c3fc4eSZi Yan * just be safe and disable write 186384c3fc4eSZi Yan */ 186484c3fc4eSZi Yan make_migration_entry_read(&entry); 186584c3fc4eSZi Yan newpmd = swp_entry_to_pmd(entry); 1866ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pmd)) 1867ab6e3d09SNaoya Horiguchi newpmd = pmd_swp_mksoft_dirty(newpmd); 186884c3fc4eSZi Yan set_pmd_at(mm, addr, pmd, newpmd); 186984c3fc4eSZi Yan } 187084c3fc4eSZi Yan goto unlock; 187184c3fc4eSZi Yan } 187284c3fc4eSZi Yan #endif 187384c3fc4eSZi Yan 1874e944fd67SMel Gorman /* 1875e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1876e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1877e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1878e944fd67SMel Gorman */ 18790a85e51dSKirill A. Shutemov if (prot_numa && is_huge_zero_pmd(*pmd)) 18800a85e51dSKirill A. Shutemov goto unlock; 1881e944fd67SMel Gorman 18820a85e51dSKirill A. Shutemov if (prot_numa && pmd_protnone(*pmd)) 18830a85e51dSKirill A. Shutemov goto unlock; 18840a85e51dSKirill A. Shutemov 1885ced10803SKirill A. Shutemov /* 1886ced10803SKirill A. Shutemov * In case prot_numa, we are under down_read(mmap_sem). It's critical 1887ced10803SKirill A. Shutemov * to not clear pmd intermittently to avoid race with MADV_DONTNEED 1888ced10803SKirill A. Shutemov * which is also under down_read(mmap_sem): 1889ced10803SKirill A. Shutemov * 1890ced10803SKirill A. Shutemov * CPU0: CPU1: 1891ced10803SKirill A. Shutemov * change_huge_pmd(prot_numa=1) 1892ced10803SKirill A. Shutemov * pmdp_huge_get_and_clear_notify() 1893ced10803SKirill A. Shutemov * madvise_dontneed() 1894ced10803SKirill A. Shutemov * zap_pmd_range() 1895ced10803SKirill A. Shutemov * pmd_trans_huge(*pmd) == 0 (without ptl) 1896ced10803SKirill A. Shutemov * // skip the pmd 1897ced10803SKirill A. Shutemov * set_pmd_at(); 1898ced10803SKirill A. Shutemov * // pmd is re-established 1899ced10803SKirill A. Shutemov * 1900ced10803SKirill A. Shutemov * The race makes MADV_DONTNEED miss the huge pmd and don't clear it 1901ced10803SKirill A. Shutemov * which may break userspace. 1902ced10803SKirill A. Shutemov * 1903ced10803SKirill A. Shutemov * pmdp_invalidate() is required to make sure we don't miss 1904ced10803SKirill A. Shutemov * dirty/young flags set by hardware. 1905ced10803SKirill A. Shutemov */ 1906ced10803SKirill A. Shutemov entry = *pmd; 1907ced10803SKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1908ced10803SKirill A. Shutemov 1909ced10803SKirill A. Shutemov /* 1910ced10803SKirill A. Shutemov * Recover dirty/young flags. It relies on pmdp_invalidate to not 1911ced10803SKirill A. Shutemov * corrupt them. 1912ced10803SKirill A. Shutemov */ 1913ced10803SKirill A. Shutemov if (pmd_dirty(*pmd)) 1914ced10803SKirill A. Shutemov entry = pmd_mkdirty(entry); 1915ced10803SKirill A. Shutemov if (pmd_young(*pmd)) 1916ced10803SKirill A. Shutemov entry = pmd_mkyoung(entry); 1917ced10803SKirill A. Shutemov 1918cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 1919b191f9b1SMel Gorman if (preserve_write) 1920288bc549SAneesh Kumar K.V entry = pmd_mk_savedwrite(entry); 1921f123d74aSMel Gorman ret = HPAGE_PMD_NR; 192256eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 19230a85e51dSKirill A. Shutemov BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); 19240a85e51dSKirill A. Shutemov unlock: 1925bf929152SKirill A. Shutemov spin_unlock(ptl); 1926cd7548abSJohannes Weiner return ret; 1927cd7548abSJohannes Weiner } 1928cd7548abSJohannes Weiner 1929025c5b24SNaoya Horiguchi /* 19308f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 1931025c5b24SNaoya Horiguchi * 19328f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 19338f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 1934025c5b24SNaoya Horiguchi */ 1935b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1936025c5b24SNaoya Horiguchi { 1937b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 1938b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 193984c3fc4eSZi Yan if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || 194084c3fc4eSZi Yan pmd_devmap(*pmd))) 1941b6ec57f4SKirill A. Shutemov return ptl; 1942b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 1943b6ec57f4SKirill A. Shutemov return NULL; 1944025c5b24SNaoya Horiguchi } 1945025c5b24SNaoya Horiguchi 1946a00cc7d9SMatthew Wilcox /* 1947a00cc7d9SMatthew Wilcox * Returns true if a given pud maps a thp, false otherwise. 1948a00cc7d9SMatthew Wilcox * 1949a00cc7d9SMatthew Wilcox * Note that if it returns true, this routine returns without unlocking page 1950a00cc7d9SMatthew Wilcox * table lock. So callers must unlock it. 1951a00cc7d9SMatthew Wilcox */ 1952a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 1953a00cc7d9SMatthew Wilcox { 1954a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1955a00cc7d9SMatthew Wilcox 1956a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 1957a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 1958a00cc7d9SMatthew Wilcox return ptl; 1959a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1960a00cc7d9SMatthew Wilcox return NULL; 1961a00cc7d9SMatthew Wilcox } 1962a00cc7d9SMatthew Wilcox 1963a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1964a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 1965a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 1966a00cc7d9SMatthew Wilcox { 1967a00cc7d9SMatthew Wilcox pud_t orig_pud; 1968a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1969a00cc7d9SMatthew Wilcox 1970a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 1971a00cc7d9SMatthew Wilcox if (!ptl) 1972a00cc7d9SMatthew Wilcox return 0; 1973a00cc7d9SMatthew Wilcox /* 1974a00cc7d9SMatthew Wilcox * For architectures like ppc64 we look at deposited pgtable 1975a00cc7d9SMatthew Wilcox * when calling pudp_huge_get_and_clear. So do the 1976a00cc7d9SMatthew Wilcox * pgtable_trans_huge_withdraw after finishing pudp related 1977a00cc7d9SMatthew Wilcox * operations. 1978a00cc7d9SMatthew Wilcox */ 1979a00cc7d9SMatthew Wilcox orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, 1980a00cc7d9SMatthew Wilcox tlb->fullmm); 1981a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 1982a00cc7d9SMatthew Wilcox if (vma_is_dax(vma)) { 1983a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1984a00cc7d9SMatthew Wilcox /* No zero page support yet */ 1985a00cc7d9SMatthew Wilcox } else { 1986a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 1987a00cc7d9SMatthew Wilcox BUG(); 1988a00cc7d9SMatthew Wilcox } 1989a00cc7d9SMatthew Wilcox return 1; 1990a00cc7d9SMatthew Wilcox } 1991a00cc7d9SMatthew Wilcox 1992a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 1993a00cc7d9SMatthew Wilcox unsigned long haddr) 1994a00cc7d9SMatthew Wilcox { 1995a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 1996a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 1997a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 1998a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 1999a00cc7d9SMatthew Wilcox 2000ce9311cfSYisheng Xie count_vm_event(THP_SPLIT_PUD); 2001a00cc7d9SMatthew Wilcox 2002a00cc7d9SMatthew Wilcox pudp_huge_clear_flush_notify(vma, haddr, pud); 2003a00cc7d9SMatthew Wilcox } 2004a00cc7d9SMatthew Wilcox 2005a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 2006a00cc7d9SMatthew Wilcox unsigned long address) 2007a00cc7d9SMatthew Wilcox { 2008a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2009a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 2010a00cc7d9SMatthew Wilcox unsigned long haddr = address & HPAGE_PUD_MASK; 2011a00cc7d9SMatthew Wilcox 2012a00cc7d9SMatthew Wilcox mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PUD_SIZE); 2013a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 2014a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 2015a00cc7d9SMatthew Wilcox goto out; 2016a00cc7d9SMatthew Wilcox __split_huge_pud_locked(vma, pud, haddr); 2017a00cc7d9SMatthew Wilcox 2018a00cc7d9SMatthew Wilcox out: 2019a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2020a00cc7d9SMatthew Wilcox mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PUD_SIZE); 2021a00cc7d9SMatthew Wilcox } 2022a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 2023a00cc7d9SMatthew Wilcox 2024eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2025eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2026eef1b3baSKirill A. Shutemov { 2027eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2028eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2029eef1b3baSKirill A. Shutemov pmd_t _pmd; 2030eef1b3baSKirill A. Shutemov int i; 2031eef1b3baSKirill A. Shutemov 2032eef1b3baSKirill A. Shutemov /* leave pmd empty until pte is filled */ 2033eef1b3baSKirill A. Shutemov pmdp_huge_clear_flush_notify(vma, haddr, pmd); 2034eef1b3baSKirill A. Shutemov 2035eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2036eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2037eef1b3baSKirill A. Shutemov 2038eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 2039eef1b3baSKirill A. Shutemov pte_t *pte, entry; 2040eef1b3baSKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 2041eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 2042eef1b3baSKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 2043eef1b3baSKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 2044eef1b3baSKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 2045eef1b3baSKirill A. Shutemov pte_unmap(pte); 2046eef1b3baSKirill A. Shutemov } 2047eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2048eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2049eef1b3baSKirill A. Shutemov } 2050eef1b3baSKirill A. Shutemov 2051eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 2052ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 2053eef1b3baSKirill A. Shutemov { 2054eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2055eef1b3baSKirill A. Shutemov struct page *page; 2056eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2057eef1b3baSKirill A. Shutemov pmd_t _pmd; 205884c3fc4eSZi Yan bool young, write, dirty, soft_dirty, pmd_migration = false; 20592ac015e2SKirill A. Shutemov unsigned long addr; 2060eef1b3baSKirill A. Shutemov int i; 2061eef1b3baSKirill A. Shutemov 2062eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 2063eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2064eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 206584c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) 206684c3fc4eSZi Yan && !pmd_devmap(*pmd)); 2067eef1b3baSKirill A. Shutemov 2068eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 2069eef1b3baSKirill A. Shutemov 2070d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 2071d21b9e57SKirill A. Shutemov _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); 2072953c66c2SAneesh Kumar K.V /* 2073953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 2074953c66c2SAneesh Kumar K.V * just go ahead and zap it 2075953c66c2SAneesh Kumar K.V */ 2076953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 2077953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 2078d21b9e57SKirill A. Shutemov if (vma_is_dax(vma)) 2079d21b9e57SKirill A. Shutemov return; 2080d21b9e57SKirill A. Shutemov page = pmd_page(_pmd); 2081d21b9e57SKirill A. Shutemov if (!PageReferenced(page) && pmd_young(_pmd)) 2082d21b9e57SKirill A. Shutemov SetPageReferenced(page); 2083d21b9e57SKirill A. Shutemov page_remove_rmap(page, true); 2084d21b9e57SKirill A. Shutemov put_page(page); 2085d21b9e57SKirill A. Shutemov add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR); 2086eef1b3baSKirill A. Shutemov return; 2087eef1b3baSKirill A. Shutemov } else if (is_huge_zero_pmd(*pmd)) { 2088eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 2089eef1b3baSKirill A. Shutemov } 2090eef1b3baSKirill A. Shutemov 209184c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 209284c3fc4eSZi Yan pmd_migration = is_pmd_migration_entry(*pmd); 209384c3fc4eSZi Yan if (pmd_migration) { 209484c3fc4eSZi Yan swp_entry_t entry; 209584c3fc4eSZi Yan 209684c3fc4eSZi Yan entry = pmd_to_swp_entry(*pmd); 209784c3fc4eSZi Yan page = pfn_to_page(swp_offset(entry)); 209884c3fc4eSZi Yan } else 209984c3fc4eSZi Yan #endif 2100eef1b3baSKirill A. Shutemov page = pmd_page(*pmd); 2101eef1b3baSKirill A. Shutemov VM_BUG_ON_PAGE(!page_count(page), page); 2102fe896d18SJoonsoo Kim page_ref_add(page, HPAGE_PMD_NR - 1); 2103eef1b3baSKirill A. Shutemov write = pmd_write(*pmd); 2104eef1b3baSKirill A. Shutemov young = pmd_young(*pmd); 2105b8d3c4c3SMinchan Kim dirty = pmd_dirty(*pmd); 2106804dd150SAndrea Arcangeli soft_dirty = pmd_soft_dirty(*pmd); 2107eef1b3baSKirill A. Shutemov 2108c777e2a8SAneesh Kumar K.V pmdp_huge_split_prepare(vma, haddr, pmd); 2109eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2110eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2111eef1b3baSKirill A. Shutemov 21122ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2113eef1b3baSKirill A. Shutemov pte_t entry, *pte; 2114eef1b3baSKirill A. Shutemov /* 2115eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 2116eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 2117eef1b3baSKirill A. Shutemov * permissions across VMAs. 2118eef1b3baSKirill A. Shutemov */ 211984c3fc4eSZi Yan if (freeze || pmd_migration) { 2120ba988280SKirill A. Shutemov swp_entry_t swp_entry; 2121ba988280SKirill A. Shutemov swp_entry = make_migration_entry(page + i, write); 2122ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 2123804dd150SAndrea Arcangeli if (soft_dirty) 2124804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 2125ba988280SKirill A. Shutemov } else { 21266d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 2127b8d3c4c3SMinchan Kim entry = maybe_mkwrite(entry, vma); 2128eef1b3baSKirill A. Shutemov if (!write) 2129eef1b3baSKirill A. Shutemov entry = pte_wrprotect(entry); 2130eef1b3baSKirill A. Shutemov if (!young) 2131eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 2132804dd150SAndrea Arcangeli if (soft_dirty) 2133804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 2134ba988280SKirill A. Shutemov } 2135b8d3c4c3SMinchan Kim if (dirty) 2136b8d3c4c3SMinchan Kim SetPageDirty(page + i); 21372ac015e2SKirill A. Shutemov pte = pte_offset_map(&_pmd, addr); 2138eef1b3baSKirill A. Shutemov BUG_ON(!pte_none(*pte)); 21392ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 2140eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 2141eef1b3baSKirill A. Shutemov pte_unmap(pte); 2142eef1b3baSKirill A. Shutemov } 2143eef1b3baSKirill A. Shutemov 2144eef1b3baSKirill A. Shutemov /* 2145eef1b3baSKirill A. Shutemov * Set PG_double_map before dropping compound_mapcount to avoid 2146eef1b3baSKirill A. Shutemov * false-negative page_mapped(). 2147eef1b3baSKirill A. Shutemov */ 2148eef1b3baSKirill A. Shutemov if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { 2149eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2150eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 2151eef1b3baSKirill A. Shutemov } 2152eef1b3baSKirill A. Shutemov 2153eef1b3baSKirill A. Shutemov if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { 2154eef1b3baSKirill A. Shutemov /* Last compound_mapcount is gone. */ 215511fb9989SMel Gorman __dec_node_page_state(page, NR_ANON_THPS); 2156eef1b3baSKirill A. Shutemov if (TestClearPageDoubleMap(page)) { 2157eef1b3baSKirill A. Shutemov /* No need in mapcount reference anymore */ 2158eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2159eef1b3baSKirill A. Shutemov atomic_dec(&page[i]._mapcount); 2160eef1b3baSKirill A. Shutemov } 2161eef1b3baSKirill A. Shutemov } 2162eef1b3baSKirill A. Shutemov 2163eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2164e9b61f19SKirill A. Shutemov /* 2165e9b61f19SKirill A. Shutemov * Up to this point the pmd is present and huge and userland has the 2166e9b61f19SKirill A. Shutemov * whole access to the hugepage during the split (which happens in 2167e9b61f19SKirill A. Shutemov * place). If we overwrite the pmd with the not-huge version pointing 2168e9b61f19SKirill A. Shutemov * to the pte here (which of course we could if all CPUs were bug 2169e9b61f19SKirill A. Shutemov * free), userland could trigger a small page size TLB miss on the 2170e9b61f19SKirill A. Shutemov * small sized TLB while the hugepage TLB entry is still established in 2171e9b61f19SKirill A. Shutemov * the huge TLB. Some CPU doesn't like that. 2172e9b61f19SKirill A. Shutemov * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum 2173e9b61f19SKirill A. Shutemov * 383 on page 93. Intel should be safe but is also warns that it's 2174e9b61f19SKirill A. Shutemov * only safe if the permission and cache attributes of the two entries 2175e9b61f19SKirill A. Shutemov * loaded in the two TLB is identical (which should be the case here). 2176e9b61f19SKirill A. Shutemov * But it is generally safer to never allow small and huge TLB entries 2177e9b61f19SKirill A. Shutemov * for the same virtual address to be loaded simultaneously. So instead 2178e9b61f19SKirill A. Shutemov * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2179e9b61f19SKirill A. Shutemov * current pmd notpresent (atomically because here the pmd_trans_huge 2180e9b61f19SKirill A. Shutemov * and pmd_trans_splitting must remain set at all times on the pmd 2181e9b61f19SKirill A. Shutemov * until the split is complete for this pmd), then we flush the SMP TLB 2182e9b61f19SKirill A. Shutemov * and finally we write the non-huge version of the pmd entry with 2183e9b61f19SKirill A. Shutemov * pmd_populate. 2184e9b61f19SKirill A. Shutemov */ 2185e9b61f19SKirill A. Shutemov pmdp_invalidate(vma, haddr, pmd); 2186eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2187e9b61f19SKirill A. Shutemov 2188e9b61f19SKirill A. Shutemov if (freeze) { 21892ac015e2SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) { 2190e9b61f19SKirill A. Shutemov page_remove_rmap(page + i, false); 2191e9b61f19SKirill A. Shutemov put_page(page + i); 2192e9b61f19SKirill A. Shutemov } 2193e9b61f19SKirill A. Shutemov } 2194eef1b3baSKirill A. Shutemov } 2195eef1b3baSKirill A. Shutemov 2196eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 219733f4751eSNaoya Horiguchi unsigned long address, bool freeze, struct page *page) 2198eef1b3baSKirill A. Shutemov { 2199eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2200eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2201eef1b3baSKirill A. Shutemov unsigned long haddr = address & HPAGE_PMD_MASK; 2202eef1b3baSKirill A. Shutemov 2203eef1b3baSKirill A. Shutemov mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE); 2204eef1b3baSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 220533f4751eSNaoya Horiguchi 220633f4751eSNaoya Horiguchi /* 220733f4751eSNaoya Horiguchi * If caller asks to setup a migration entries, we need a page to check 220833f4751eSNaoya Horiguchi * pmd against. Otherwise we can end up replacing wrong page. 220933f4751eSNaoya Horiguchi */ 221033f4751eSNaoya Horiguchi VM_BUG_ON(freeze && !page); 221133f4751eSNaoya Horiguchi if (page && page != pmd_page(*pmd)) 221233f4751eSNaoya Horiguchi goto out; 221333f4751eSNaoya Horiguchi 22145c7fb56eSDan Williams if (pmd_trans_huge(*pmd)) { 221533f4751eSNaoya Horiguchi page = pmd_page(*pmd); 2216e90309c9SKirill A. Shutemov if (PageMlocked(page)) 22175f737714SKirill A. Shutemov clear_page_mlock(page); 221884c3fc4eSZi Yan } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) 22195c7fb56eSDan Williams goto out; 2220fec89c10SKirill A. Shutemov __split_huge_pmd_locked(vma, pmd, haddr, freeze); 2221e90309c9SKirill A. Shutemov out: 2222eef1b3baSKirill A. Shutemov spin_unlock(ptl); 2223eef1b3baSKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE); 2224eef1b3baSKirill A. Shutemov } 2225eef1b3baSKirill A. Shutemov 2226fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2227fec89c10SKirill A. Shutemov bool freeze, struct page *page) 222894fcc585SAndrea Arcangeli { 2229f72e7dcdSHugh Dickins pgd_t *pgd; 2230c2febafcSKirill A. Shutemov p4d_t *p4d; 2231f72e7dcdSHugh Dickins pud_t *pud; 223294fcc585SAndrea Arcangeli pmd_t *pmd; 223394fcc585SAndrea Arcangeli 223478ddc534SKirill A. Shutemov pgd = pgd_offset(vma->vm_mm, address); 2235f72e7dcdSHugh Dickins if (!pgd_present(*pgd)) 2236f72e7dcdSHugh Dickins return; 2237f72e7dcdSHugh Dickins 2238c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, address); 2239c2febafcSKirill A. Shutemov if (!p4d_present(*p4d)) 2240c2febafcSKirill A. Shutemov return; 2241c2febafcSKirill A. Shutemov 2242c2febafcSKirill A. Shutemov pud = pud_offset(p4d, address); 2243f72e7dcdSHugh Dickins if (!pud_present(*pud)) 2244f72e7dcdSHugh Dickins return; 2245f72e7dcdSHugh Dickins 2246f72e7dcdSHugh Dickins pmd = pmd_offset(pud, address); 2247fec89c10SKirill A. Shutemov 224833f4751eSNaoya Horiguchi __split_huge_pmd(vma, pmd, address, freeze, page); 224994fcc585SAndrea Arcangeli } 225094fcc585SAndrea Arcangeli 2251e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 225294fcc585SAndrea Arcangeli unsigned long start, 225394fcc585SAndrea Arcangeli unsigned long end, 225494fcc585SAndrea Arcangeli long adjust_next) 225594fcc585SAndrea Arcangeli { 225694fcc585SAndrea Arcangeli /* 225794fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 225894fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 225994fcc585SAndrea Arcangeli * an huge pmd. 226094fcc585SAndrea Arcangeli */ 226194fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 226294fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 226394fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 2264fec89c10SKirill A. Shutemov split_huge_pmd_address(vma, start, false, NULL); 226594fcc585SAndrea Arcangeli 226694fcc585SAndrea Arcangeli /* 226794fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 226894fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 226994fcc585SAndrea Arcangeli * an huge pmd. 227094fcc585SAndrea Arcangeli */ 227194fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 227294fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 227394fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 2274fec89c10SKirill A. Shutemov split_huge_pmd_address(vma, end, false, NULL); 227594fcc585SAndrea Arcangeli 227694fcc585SAndrea Arcangeli /* 227794fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 227894fcc585SAndrea Arcangeli * vm_next->vm_start isn't page aligned and it could previously 227994fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 228094fcc585SAndrea Arcangeli */ 228194fcc585SAndrea Arcangeli if (adjust_next > 0) { 228294fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 228394fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 228494fcc585SAndrea Arcangeli nstart += adjust_next << PAGE_SHIFT; 228594fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 228694fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 228794fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 2288fec89c10SKirill A. Shutemov split_huge_pmd_address(next, nstart, false, NULL); 228994fcc585SAndrea Arcangeli } 229094fcc585SAndrea Arcangeli } 2291e9b61f19SKirill A. Shutemov 2292fec89c10SKirill A. Shutemov static void freeze_page(struct page *page) 2293e9b61f19SKirill A. Shutemov { 2294baa355fdSKirill A. Shutemov enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | 2295c7ab0d2fSKirill A. Shutemov TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; 2296666e5a40SMinchan Kim bool unmap_success; 2297e9b61f19SKirill A. Shutemov 2298e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageHead(page), page); 2299e9b61f19SKirill A. Shutemov 2300baa355fdSKirill A. Shutemov if (PageAnon(page)) 2301b5ff8161SNaoya Horiguchi ttu_flags |= TTU_SPLIT_FREEZE; 2302baa355fdSKirill A. Shutemov 2303666e5a40SMinchan Kim unmap_success = try_to_unmap(page, ttu_flags); 2304666e5a40SMinchan Kim VM_BUG_ON_PAGE(!unmap_success, page); 2305bd56086fSKirill A. Shutemov } 2306bd56086fSKirill A. Shutemov 2307fec89c10SKirill A. Shutemov static void unfreeze_page(struct page *page) 2308e9b61f19SKirill A. Shutemov { 2309fec89c10SKirill A. Shutemov int i; 2310ace71a19SKirill A. Shutemov if (PageTransHuge(page)) { 2311ace71a19SKirill A. Shutemov remove_migration_ptes(page, page, true); 2312ace71a19SKirill A. Shutemov } else { 2313fec89c10SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2314fec89c10SKirill A. Shutemov remove_migration_ptes(page + i, page + i, true); 2315e9b61f19SKirill A. Shutemov } 2316ace71a19SKirill A. Shutemov } 2317e9b61f19SKirill A. Shutemov 23188df651c7SKirill A. Shutemov static void __split_huge_page_tail(struct page *head, int tail, 2319e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2320e9b61f19SKirill A. Shutemov { 2321e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 2322e9b61f19SKirill A. Shutemov 23238df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2324fe896d18SJoonsoo Kim VM_BUG_ON_PAGE(page_ref_count(page_tail) != 0, page_tail); 2325e9b61f19SKirill A. Shutemov 2326e9b61f19SKirill A. Shutemov /* 23270139aa7bSJoonsoo Kim * tail_page->_refcount is zero and not changing from under us. But 2328e9b61f19SKirill A. Shutemov * get_page_unless_zero() may be running from under us on the 2329baa355fdSKirill A. Shutemov * tail_page. If we used atomic_set() below instead of atomic_inc() or 2330baa355fdSKirill A. Shutemov * atomic_add(), we would then run atomic_set() concurrently with 2331e9b61f19SKirill A. Shutemov * get_page_unless_zero(), and atomic_set() is implemented in C not 2332e9b61f19SKirill A. Shutemov * using locked ops. spin_unlock on x86 sometime uses locked ops 2333e9b61f19SKirill A. Shutemov * because of PPro errata 66, 92, so unless somebody can guarantee 2334e9b61f19SKirill A. Shutemov * atomic_set() here would be safe on all archs (and not only on x86), 2335baa355fdSKirill A. Shutemov * it's safer to use atomic_inc()/atomic_add(). 2336e9b61f19SKirill A. Shutemov */ 233738d8b4e6SHuang Ying if (PageAnon(head) && !PageSwapCache(head)) { 2338fe896d18SJoonsoo Kim page_ref_inc(page_tail); 2339baa355fdSKirill A. Shutemov } else { 2340baa355fdSKirill A. Shutemov /* Additional pin to radix tree */ 2341baa355fdSKirill A. Shutemov page_ref_add(page_tail, 2); 2342baa355fdSKirill A. Shutemov } 2343e9b61f19SKirill A. Shutemov 2344e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2345e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2346e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2347e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 234838d8b4e6SHuang Ying (1L << PG_swapcache) | 2349e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2350e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2351e9b61f19SKirill A. Shutemov (1L << PG_active) | 2352e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2353b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 2354b8d3c4c3SMinchan Kim (1L << PG_dirty))); 2355e9b61f19SKirill A. Shutemov 2356e9b61f19SKirill A. Shutemov /* 2357e9b61f19SKirill A. Shutemov * After clearing PageTail the gup refcount can be released. 2358e9b61f19SKirill A. Shutemov * Page flags also must be visible before we make the page non-compound. 2359e9b61f19SKirill A. Shutemov */ 2360e9b61f19SKirill A. Shutemov smp_wmb(); 2361e9b61f19SKirill A. Shutemov 2362e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2363e9b61f19SKirill A. Shutemov 2364e9b61f19SKirill A. Shutemov if (page_is_young(head)) 2365e9b61f19SKirill A. Shutemov set_page_young(page_tail); 2366e9b61f19SKirill A. Shutemov if (page_is_idle(head)) 2367e9b61f19SKirill A. Shutemov set_page_idle(page_tail); 2368e9b61f19SKirill A. Shutemov 2369e9b61f19SKirill A. Shutemov /* ->mapping in first tail page is compound_mapcount */ 23709a982250SKirill A. Shutemov VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2371e9b61f19SKirill A. Shutemov page_tail); 2372e9b61f19SKirill A. Shutemov page_tail->mapping = head->mapping; 2373e9b61f19SKirill A. Shutemov 2374e9b61f19SKirill A. Shutemov page_tail->index = head->index + tail; 2375e9b61f19SKirill A. Shutemov page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); 2376e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2377e9b61f19SKirill A. Shutemov } 2378e9b61f19SKirill A. Shutemov 2379baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2380baa355fdSKirill A. Shutemov unsigned long flags) 2381e9b61f19SKirill A. Shutemov { 2382e9b61f19SKirill A. Shutemov struct page *head = compound_head(page); 2383e9b61f19SKirill A. Shutemov struct zone *zone = page_zone(head); 2384e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 2385baa355fdSKirill A. Shutemov pgoff_t end = -1; 23868df651c7SKirill A. Shutemov int i; 2387e9b61f19SKirill A. Shutemov 2388599d0c95SMel Gorman lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat); 2389e9b61f19SKirill A. Shutemov 2390e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2391e9b61f19SKirill A. Shutemov mem_cgroup_split_huge_fixup(head); 2392e9b61f19SKirill A. Shutemov 2393baa355fdSKirill A. Shutemov if (!PageAnon(page)) 2394baa355fdSKirill A. Shutemov end = DIV_ROUND_UP(i_size_read(head->mapping->host), PAGE_SIZE); 2395baa355fdSKirill A. Shutemov 2396baa355fdSKirill A. Shutemov for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { 23978df651c7SKirill A. Shutemov __split_huge_page_tail(head, i, lruvec, list); 2398baa355fdSKirill A. Shutemov /* Some pages can be beyond i_size: drop them from page cache */ 2399baa355fdSKirill A. Shutemov if (head[i].index >= end) { 2400baa355fdSKirill A. Shutemov __ClearPageDirty(head + i); 2401baa355fdSKirill A. Shutemov __delete_from_page_cache(head + i, NULL); 2402800d8c63SKirill A. Shutemov if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) 2403800d8c63SKirill A. Shutemov shmem_uncharge(head->mapping->host, 1); 2404baa355fdSKirill A. Shutemov put_page(head + i); 2405baa355fdSKirill A. Shutemov } 2406baa355fdSKirill A. Shutemov } 2407e9b61f19SKirill A. Shutemov 2408e9b61f19SKirill A. Shutemov ClearPageCompound(head); 2409baa355fdSKirill A. Shutemov /* See comment in __split_huge_page_tail() */ 2410baa355fdSKirill A. Shutemov if (PageAnon(head)) { 241138d8b4e6SHuang Ying /* Additional pin to radix tree of swap cache */ 241238d8b4e6SHuang Ying if (PageSwapCache(head)) 241338d8b4e6SHuang Ying page_ref_add(head, 2); 241438d8b4e6SHuang Ying else 2415baa355fdSKirill A. Shutemov page_ref_inc(head); 2416baa355fdSKirill A. Shutemov } else { 2417baa355fdSKirill A. Shutemov /* Additional pin to radix tree */ 2418baa355fdSKirill A. Shutemov page_ref_add(head, 2); 2419baa355fdSKirill A. Shutemov spin_unlock(&head->mapping->tree_lock); 2420baa355fdSKirill A. Shutemov } 2421baa355fdSKirill A. Shutemov 2422a52633d8SMel Gorman spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); 2423e9b61f19SKirill A. Shutemov 2424fec89c10SKirill A. Shutemov unfreeze_page(head); 2425e9b61f19SKirill A. Shutemov 2426e9b61f19SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) { 2427e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2428e9b61f19SKirill A. Shutemov if (subpage == page) 2429e9b61f19SKirill A. Shutemov continue; 2430e9b61f19SKirill A. Shutemov unlock_page(subpage); 2431e9b61f19SKirill A. Shutemov 2432e9b61f19SKirill A. Shutemov /* 2433e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2434e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2435e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2436e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2437e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2438e9b61f19SKirill A. Shutemov */ 2439e9b61f19SKirill A. Shutemov put_page(subpage); 2440e9b61f19SKirill A. Shutemov } 2441e9b61f19SKirill A. Shutemov } 2442e9b61f19SKirill A. Shutemov 2443b20ce5e0SKirill A. Shutemov int total_mapcount(struct page *page) 2444b20ce5e0SKirill A. Shutemov { 2445dd78feddSKirill A. Shutemov int i, compound, ret; 2446b20ce5e0SKirill A. Shutemov 2447b20ce5e0SKirill A. Shutemov VM_BUG_ON_PAGE(PageTail(page), page); 2448b20ce5e0SKirill A. Shutemov 2449b20ce5e0SKirill A. Shutemov if (likely(!PageCompound(page))) 2450b20ce5e0SKirill A. Shutemov return atomic_read(&page->_mapcount) + 1; 2451b20ce5e0SKirill A. Shutemov 2452dd78feddSKirill A. Shutemov compound = compound_mapcount(page); 2453b20ce5e0SKirill A. Shutemov if (PageHuge(page)) 2454dd78feddSKirill A. Shutemov return compound; 2455dd78feddSKirill A. Shutemov ret = compound; 2456b20ce5e0SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2457b20ce5e0SKirill A. Shutemov ret += atomic_read(&page[i]._mapcount) + 1; 2458dd78feddSKirill A. Shutemov /* File pages has compound_mapcount included in _mapcount */ 2459dd78feddSKirill A. Shutemov if (!PageAnon(page)) 2460dd78feddSKirill A. Shutemov return ret - compound * HPAGE_PMD_NR; 2461b20ce5e0SKirill A. Shutemov if (PageDoubleMap(page)) 2462b20ce5e0SKirill A. Shutemov ret -= HPAGE_PMD_NR; 2463b20ce5e0SKirill A. Shutemov return ret; 2464b20ce5e0SKirill A. Shutemov } 2465b20ce5e0SKirill A. Shutemov 2466e9b61f19SKirill A. Shutemov /* 24676d0a07edSAndrea Arcangeli * This calculates accurately how many mappings a transparent hugepage 24686d0a07edSAndrea Arcangeli * has (unlike page_mapcount() which isn't fully accurate). This full 24696d0a07edSAndrea Arcangeli * accuracy is primarily needed to know if copy-on-write faults can 24706d0a07edSAndrea Arcangeli * reuse the page and change the mapping to read-write instead of 24716d0a07edSAndrea Arcangeli * copying them. At the same time this returns the total_mapcount too. 24726d0a07edSAndrea Arcangeli * 24736d0a07edSAndrea Arcangeli * The function returns the highest mapcount any one of the subpages 24746d0a07edSAndrea Arcangeli * has. If the return value is one, even if different processes are 24756d0a07edSAndrea Arcangeli * mapping different subpages of the transparent hugepage, they can 24766d0a07edSAndrea Arcangeli * all reuse it, because each process is reusing a different subpage. 24776d0a07edSAndrea Arcangeli * 24786d0a07edSAndrea Arcangeli * The total_mapcount is instead counting all virtual mappings of the 24796d0a07edSAndrea Arcangeli * subpages. If the total_mapcount is equal to "one", it tells the 24806d0a07edSAndrea Arcangeli * caller all mappings belong to the same "mm" and in turn the 24816d0a07edSAndrea Arcangeli * anon_vma of the transparent hugepage can become the vma->anon_vma 24826d0a07edSAndrea Arcangeli * local one as no other process may be mapping any of the subpages. 24836d0a07edSAndrea Arcangeli * 24846d0a07edSAndrea Arcangeli * It would be more accurate to replace page_mapcount() with 24856d0a07edSAndrea Arcangeli * page_trans_huge_mapcount(), however we only use 24866d0a07edSAndrea Arcangeli * page_trans_huge_mapcount() in the copy-on-write faults where we 24876d0a07edSAndrea Arcangeli * need full accuracy to avoid breaking page pinning, because 24886d0a07edSAndrea Arcangeli * page_trans_huge_mapcount() is slower than page_mapcount(). 24896d0a07edSAndrea Arcangeli */ 24906d0a07edSAndrea Arcangeli int page_trans_huge_mapcount(struct page *page, int *total_mapcount) 24916d0a07edSAndrea Arcangeli { 24926d0a07edSAndrea Arcangeli int i, ret, _total_mapcount, mapcount; 24936d0a07edSAndrea Arcangeli 24946d0a07edSAndrea Arcangeli /* hugetlbfs shouldn't call it */ 24956d0a07edSAndrea Arcangeli VM_BUG_ON_PAGE(PageHuge(page), page); 24966d0a07edSAndrea Arcangeli 24976d0a07edSAndrea Arcangeli if (likely(!PageTransCompound(page))) { 24986d0a07edSAndrea Arcangeli mapcount = atomic_read(&page->_mapcount) + 1; 24996d0a07edSAndrea Arcangeli if (total_mapcount) 25006d0a07edSAndrea Arcangeli *total_mapcount = mapcount; 25016d0a07edSAndrea Arcangeli return mapcount; 25026d0a07edSAndrea Arcangeli } 25036d0a07edSAndrea Arcangeli 25046d0a07edSAndrea Arcangeli page = compound_head(page); 25056d0a07edSAndrea Arcangeli 25066d0a07edSAndrea Arcangeli _total_mapcount = ret = 0; 25076d0a07edSAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 25086d0a07edSAndrea Arcangeli mapcount = atomic_read(&page[i]._mapcount) + 1; 25096d0a07edSAndrea Arcangeli ret = max(ret, mapcount); 25106d0a07edSAndrea Arcangeli _total_mapcount += mapcount; 25116d0a07edSAndrea Arcangeli } 25126d0a07edSAndrea Arcangeli if (PageDoubleMap(page)) { 25136d0a07edSAndrea Arcangeli ret -= 1; 25146d0a07edSAndrea Arcangeli _total_mapcount -= HPAGE_PMD_NR; 25156d0a07edSAndrea Arcangeli } 25166d0a07edSAndrea Arcangeli mapcount = compound_mapcount(page); 25176d0a07edSAndrea Arcangeli ret += mapcount; 25186d0a07edSAndrea Arcangeli _total_mapcount += mapcount; 25196d0a07edSAndrea Arcangeli if (total_mapcount) 25206d0a07edSAndrea Arcangeli *total_mapcount = _total_mapcount; 25216d0a07edSAndrea Arcangeli return ret; 25226d0a07edSAndrea Arcangeli } 25236d0a07edSAndrea Arcangeli 2524b8f593cdSHuang Ying /* Racy check whether the huge page can be split */ 2525b8f593cdSHuang Ying bool can_split_huge_page(struct page *page, int *pextra_pins) 2526b8f593cdSHuang Ying { 2527b8f593cdSHuang Ying int extra_pins; 2528b8f593cdSHuang Ying 2529b8f593cdSHuang Ying /* Additional pins from radix tree */ 2530b8f593cdSHuang Ying if (PageAnon(page)) 2531b8f593cdSHuang Ying extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; 2532b8f593cdSHuang Ying else 2533b8f593cdSHuang Ying extra_pins = HPAGE_PMD_NR; 2534b8f593cdSHuang Ying if (pextra_pins) 2535b8f593cdSHuang Ying *pextra_pins = extra_pins; 2536b8f593cdSHuang Ying return total_mapcount(page) == page_count(page) - extra_pins - 1; 2537b8f593cdSHuang Ying } 2538b8f593cdSHuang Ying 25396d0a07edSAndrea Arcangeli /* 2540e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2541e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2542e9b61f19SKirill A. Shutemov * 2543e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2544e9b61f19SKirill A. Shutemov * The huge page must be locked. 2545e9b61f19SKirill A. Shutemov * 2546e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2547e9b61f19SKirill A. Shutemov * 2548e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2549e9b61f19SKirill A. Shutemov * the hugepage. 2550e9b61f19SKirill A. Shutemov * 2551e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2552e9b61f19SKirill A. Shutemov * they are not mapped. 2553e9b61f19SKirill A. Shutemov * 2554e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2555e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2556e9b61f19SKirill A. Shutemov * us. 2557e9b61f19SKirill A. Shutemov */ 2558e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2559e9b61f19SKirill A. Shutemov { 2560e9b61f19SKirill A. Shutemov struct page *head = compound_head(page); 2561a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); 2562baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2563baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2564baa355fdSKirill A. Shutemov int count, mapcount, extra_pins, ret; 2565d9654322SKirill A. Shutemov bool mlocked; 25660b9b6fffSKirill A. Shutemov unsigned long flags; 2567e9b61f19SKirill A. Shutemov 2568e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(is_huge_zero_page(page), page); 2569e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2570e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageCompound(page), page); 2571e9b61f19SKirill A. Shutemov 257259807685SHuang Ying if (PageWriteback(page)) 257359807685SHuang Ying return -EBUSY; 257459807685SHuang Ying 2575baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2576e9b61f19SKirill A. Shutemov /* 2577baa355fdSKirill A. Shutemov * The caller does not necessarily hold an mmap_sem that would 2578baa355fdSKirill A. Shutemov * prevent the anon_vma disappearing so we first we take a 2579baa355fdSKirill A. Shutemov * reference to it and then lock the anon_vma for write. This 2580baa355fdSKirill A. Shutemov * is similar to page_lock_anon_vma_read except the write lock 2581baa355fdSKirill A. Shutemov * is taken to serialise against parallel split or collapse 2582baa355fdSKirill A. Shutemov * operations. 2583e9b61f19SKirill A. Shutemov */ 2584e9b61f19SKirill A. Shutemov anon_vma = page_get_anon_vma(head); 2585e9b61f19SKirill A. Shutemov if (!anon_vma) { 2586e9b61f19SKirill A. Shutemov ret = -EBUSY; 2587e9b61f19SKirill A. Shutemov goto out; 2588e9b61f19SKirill A. Shutemov } 2589baa355fdSKirill A. Shutemov mapping = NULL; 2590e9b61f19SKirill A. Shutemov anon_vma_lock_write(anon_vma); 2591baa355fdSKirill A. Shutemov } else { 2592baa355fdSKirill A. Shutemov mapping = head->mapping; 2593baa355fdSKirill A. Shutemov 2594baa355fdSKirill A. Shutemov /* Truncated ? */ 2595baa355fdSKirill A. Shutemov if (!mapping) { 2596baa355fdSKirill A. Shutemov ret = -EBUSY; 2597baa355fdSKirill A. Shutemov goto out; 2598baa355fdSKirill A. Shutemov } 2599baa355fdSKirill A. Shutemov 2600baa355fdSKirill A. Shutemov anon_vma = NULL; 2601baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 2602baa355fdSKirill A. Shutemov } 2603e9b61f19SKirill A. Shutemov 2604e9b61f19SKirill A. Shutemov /* 2605e9b61f19SKirill A. Shutemov * Racy check if we can split the page, before freeze_page() will 2606e9b61f19SKirill A. Shutemov * split PMDs 2607e9b61f19SKirill A. Shutemov */ 2608b8f593cdSHuang Ying if (!can_split_huge_page(head, &extra_pins)) { 2609e9b61f19SKirill A. Shutemov ret = -EBUSY; 2610e9b61f19SKirill A. Shutemov goto out_unlock; 2611e9b61f19SKirill A. Shutemov } 2612e9b61f19SKirill A. Shutemov 2613d9654322SKirill A. Shutemov mlocked = PageMlocked(page); 2614fec89c10SKirill A. Shutemov freeze_page(head); 2615e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(compound_mapcount(head), head); 2616e9b61f19SKirill A. Shutemov 2617d9654322SKirill A. Shutemov /* Make sure the page is not on per-CPU pagevec as it takes pin */ 2618d9654322SKirill A. Shutemov if (mlocked) 2619d9654322SKirill A. Shutemov lru_add_drain(); 2620d9654322SKirill A. Shutemov 2621baa355fdSKirill A. Shutemov /* prevent PageLRU to go away from under us, and freeze lru stats */ 2622a52633d8SMel Gorman spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags); 2623baa355fdSKirill A. Shutemov 2624baa355fdSKirill A. Shutemov if (mapping) { 2625baa355fdSKirill A. Shutemov void **pslot; 2626baa355fdSKirill A. Shutemov 2627baa355fdSKirill A. Shutemov spin_lock(&mapping->tree_lock); 2628baa355fdSKirill A. Shutemov pslot = radix_tree_lookup_slot(&mapping->page_tree, 2629baa355fdSKirill A. Shutemov page_index(head)); 2630baa355fdSKirill A. Shutemov /* 2631baa355fdSKirill A. Shutemov * Check if the head page is present in radix tree. 2632baa355fdSKirill A. Shutemov * We assume all tail are present too, if head is there. 2633baa355fdSKirill A. Shutemov */ 2634baa355fdSKirill A. Shutemov if (radix_tree_deref_slot_protected(pslot, 2635baa355fdSKirill A. Shutemov &mapping->tree_lock) != head) 2636baa355fdSKirill A. Shutemov goto fail; 2637baa355fdSKirill A. Shutemov } 2638baa355fdSKirill A. Shutemov 26390139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 2640baa355fdSKirill A. Shutemov spin_lock(&pgdata->split_queue_lock); 2641e9b61f19SKirill A. Shutemov count = page_count(head); 2642e9b61f19SKirill A. Shutemov mapcount = total_mapcount(head); 2643baa355fdSKirill A. Shutemov if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { 26449a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(head))) { 2645a3d0a918SKirill A. Shutemov pgdata->split_queue_len--; 26469a982250SKirill A. Shutemov list_del(page_deferred_list(head)); 26479a982250SKirill A. Shutemov } 264865c45377SKirill A. Shutemov if (mapping) 264911fb9989SMel Gorman __dec_node_page_state(page, NR_SHMEM_THPS); 2650baa355fdSKirill A. Shutemov spin_unlock(&pgdata->split_queue_lock); 2651baa355fdSKirill A. Shutemov __split_huge_page(page, list, flags); 265259807685SHuang Ying if (PageSwapCache(head)) { 265359807685SHuang Ying swp_entry_t entry = { .val = page_private(head) }; 265459807685SHuang Ying 265559807685SHuang Ying ret = split_swap_cluster(entry); 265659807685SHuang Ying } else 2657e9b61f19SKirill A. Shutemov ret = 0; 2658baa355fdSKirill A. Shutemov } else { 2659baa355fdSKirill A. Shutemov if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { 2660e9b61f19SKirill A. Shutemov pr_alert("total_mapcount: %u, page_count(): %u\n", 2661e9b61f19SKirill A. Shutemov mapcount, count); 2662e9b61f19SKirill A. Shutemov if (PageTail(page)) 2663e9b61f19SKirill A. Shutemov dump_page(head, NULL); 2664bd56086fSKirill A. Shutemov dump_page(page, "total_mapcount(head) > 0"); 2665e9b61f19SKirill A. Shutemov BUG(); 2666baa355fdSKirill A. Shutemov } 2667baa355fdSKirill A. Shutemov spin_unlock(&pgdata->split_queue_lock); 2668baa355fdSKirill A. Shutemov fail: if (mapping) 2669baa355fdSKirill A. Shutemov spin_unlock(&mapping->tree_lock); 2670a52633d8SMel Gorman spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); 2671fec89c10SKirill A. Shutemov unfreeze_page(head); 2672e9b61f19SKirill A. Shutemov ret = -EBUSY; 2673e9b61f19SKirill A. Shutemov } 2674e9b61f19SKirill A. Shutemov 2675e9b61f19SKirill A. Shutemov out_unlock: 2676baa355fdSKirill A. Shutemov if (anon_vma) { 2677e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 2678e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 2679baa355fdSKirill A. Shutemov } 2680baa355fdSKirill A. Shutemov if (mapping) 2681baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 2682e9b61f19SKirill A. Shutemov out: 2683e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 2684e9b61f19SKirill A. Shutemov return ret; 2685e9b61f19SKirill A. Shutemov } 26869a982250SKirill A. Shutemov 26879a982250SKirill A. Shutemov void free_transhuge_page(struct page *page) 26889a982250SKirill A. Shutemov { 2689a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); 26909a982250SKirill A. Shutemov unsigned long flags; 26919a982250SKirill A. Shutemov 2692a3d0a918SKirill A. Shutemov spin_lock_irqsave(&pgdata->split_queue_lock, flags); 26939a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(page))) { 2694a3d0a918SKirill A. Shutemov pgdata->split_queue_len--; 26959a982250SKirill A. Shutemov list_del(page_deferred_list(page)); 26969a982250SKirill A. Shutemov } 2697a3d0a918SKirill A. Shutemov spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); 26989a982250SKirill A. Shutemov free_compound_page(page); 26999a982250SKirill A. Shutemov } 27009a982250SKirill A. Shutemov 27019a982250SKirill A. Shutemov void deferred_split_huge_page(struct page *page) 27029a982250SKirill A. Shutemov { 2703a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); 27049a982250SKirill A. Shutemov unsigned long flags; 27059a982250SKirill A. Shutemov 27069a982250SKirill A. Shutemov VM_BUG_ON_PAGE(!PageTransHuge(page), page); 27079a982250SKirill A. Shutemov 2708a3d0a918SKirill A. Shutemov spin_lock_irqsave(&pgdata->split_queue_lock, flags); 27099a982250SKirill A. Shutemov if (list_empty(page_deferred_list(page))) { 2710f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 2711a3d0a918SKirill A. Shutemov list_add_tail(page_deferred_list(page), &pgdata->split_queue); 2712a3d0a918SKirill A. Shutemov pgdata->split_queue_len++; 27139a982250SKirill A. Shutemov } 2714a3d0a918SKirill A. Shutemov spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); 27159a982250SKirill A. Shutemov } 27169a982250SKirill A. Shutemov 27179a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 27189a982250SKirill A. Shutemov struct shrink_control *sc) 27199a982250SKirill A. Shutemov { 2720a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2721cb8d68ecSKirill A. Shutemov return ACCESS_ONCE(pgdata->split_queue_len); 27229a982250SKirill A. Shutemov } 27239a982250SKirill A. Shutemov 27249a982250SKirill A. Shutemov static unsigned long deferred_split_scan(struct shrinker *shrink, 27259a982250SKirill A. Shutemov struct shrink_control *sc) 27269a982250SKirill A. Shutemov { 2727a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 27289a982250SKirill A. Shutemov unsigned long flags; 27299a982250SKirill A. Shutemov LIST_HEAD(list), *pos, *next; 27309a982250SKirill A. Shutemov struct page *page; 27319a982250SKirill A. Shutemov int split = 0; 27329a982250SKirill A. Shutemov 2733a3d0a918SKirill A. Shutemov spin_lock_irqsave(&pgdata->split_queue_lock, flags); 27349a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 2735ae026204SKirill A. Shutemov list_for_each_safe(pos, next, &pgdata->split_queue) { 27369a982250SKirill A. Shutemov page = list_entry((void *)pos, struct page, mapping); 27379a982250SKirill A. Shutemov page = compound_head(page); 2738e3ae1953SKirill A. Shutemov if (get_page_unless_zero(page)) { 2739e3ae1953SKirill A. Shutemov list_move(page_deferred_list(page), &list); 2740e3ae1953SKirill A. Shutemov } else { 2741e3ae1953SKirill A. Shutemov /* We lost race with put_compound_page() */ 27429a982250SKirill A. Shutemov list_del_init(page_deferred_list(page)); 2743a3d0a918SKirill A. Shutemov pgdata->split_queue_len--; 27449a982250SKirill A. Shutemov } 2745e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 2746e3ae1953SKirill A. Shutemov break; 27479a982250SKirill A. Shutemov } 2748a3d0a918SKirill A. Shutemov spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); 27499a982250SKirill A. Shutemov 27509a982250SKirill A. Shutemov list_for_each_safe(pos, next, &list) { 27519a982250SKirill A. Shutemov page = list_entry((void *)pos, struct page, mapping); 27529a982250SKirill A. Shutemov lock_page(page); 27539a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 27549a982250SKirill A. Shutemov if (!split_huge_page(page)) 27559a982250SKirill A. Shutemov split++; 27569a982250SKirill A. Shutemov unlock_page(page); 27579a982250SKirill A. Shutemov put_page(page); 27589a982250SKirill A. Shutemov } 27599a982250SKirill A. Shutemov 2760a3d0a918SKirill A. Shutemov spin_lock_irqsave(&pgdata->split_queue_lock, flags); 2761a3d0a918SKirill A. Shutemov list_splice_tail(&list, &pgdata->split_queue); 2762a3d0a918SKirill A. Shutemov spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); 27639a982250SKirill A. Shutemov 2764cb8d68ecSKirill A. Shutemov /* 2765cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 2766cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 2767cb8d68ecSKirill A. Shutemov */ 2768cb8d68ecSKirill A. Shutemov if (!split && list_empty(&pgdata->split_queue)) 2769cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 2770cb8d68ecSKirill A. Shutemov return split; 27719a982250SKirill A. Shutemov } 27729a982250SKirill A. Shutemov 27739a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker = { 27749a982250SKirill A. Shutemov .count_objects = deferred_split_count, 27759a982250SKirill A. Shutemov .scan_objects = deferred_split_scan, 27769a982250SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 2777a3d0a918SKirill A. Shutemov .flags = SHRINKER_NUMA_AWARE, 27789a982250SKirill A. Shutemov }; 277949071d43SKirill A. Shutemov 278049071d43SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 278149071d43SKirill A. Shutemov static int split_huge_pages_set(void *data, u64 val) 278249071d43SKirill A. Shutemov { 278349071d43SKirill A. Shutemov struct zone *zone; 278449071d43SKirill A. Shutemov struct page *page; 278549071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 278649071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 278749071d43SKirill A. Shutemov 278849071d43SKirill A. Shutemov if (val != 1) 278949071d43SKirill A. Shutemov return -EINVAL; 279049071d43SKirill A. Shutemov 279149071d43SKirill A. Shutemov for_each_populated_zone(zone) { 279249071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 279349071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 279449071d43SKirill A. Shutemov if (!pfn_valid(pfn)) 279549071d43SKirill A. Shutemov continue; 279649071d43SKirill A. Shutemov 279749071d43SKirill A. Shutemov page = pfn_to_page(pfn); 279849071d43SKirill A. Shutemov if (!get_page_unless_zero(page)) 279949071d43SKirill A. Shutemov continue; 280049071d43SKirill A. Shutemov 280149071d43SKirill A. Shutemov if (zone != page_zone(page)) 280249071d43SKirill A. Shutemov goto next; 280349071d43SKirill A. Shutemov 2804baa355fdSKirill A. Shutemov if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) 280549071d43SKirill A. Shutemov goto next; 280649071d43SKirill A. Shutemov 280749071d43SKirill A. Shutemov total++; 280849071d43SKirill A. Shutemov lock_page(page); 280949071d43SKirill A. Shutemov if (!split_huge_page(page)) 281049071d43SKirill A. Shutemov split++; 281149071d43SKirill A. Shutemov unlock_page(page); 281249071d43SKirill A. Shutemov next: 281349071d43SKirill A. Shutemov put_page(page); 281449071d43SKirill A. Shutemov } 281549071d43SKirill A. Shutemov } 281649071d43SKirill A. Shutemov 2817145bdaa1SYang Shi pr_info("%lu of %lu THP split\n", split, total); 281849071d43SKirill A. Shutemov 281949071d43SKirill A. Shutemov return 0; 282049071d43SKirill A. Shutemov } 282149071d43SKirill A. Shutemov DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, 282249071d43SKirill A. Shutemov "%llu\n"); 282349071d43SKirill A. Shutemov 282449071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 282549071d43SKirill A. Shutemov { 282649071d43SKirill A. Shutemov void *ret; 282749071d43SKirill A. Shutemov 2828145bdaa1SYang Shi ret = debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 282949071d43SKirill A. Shutemov &split_huge_pages_fops); 283049071d43SKirill A. Shutemov if (!ret) 283149071d43SKirill A. Shutemov pr_warn("Failed to create split_huge_pages in debugfs"); 283249071d43SKirill A. Shutemov return 0; 283349071d43SKirill A. Shutemov } 283449071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 283549071d43SKirill A. Shutemov #endif 2836616b8371SZi Yan 2837616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 2838616b8371SZi Yan void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 2839616b8371SZi Yan struct page *page) 2840616b8371SZi Yan { 2841616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 2842616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 2843616b8371SZi Yan unsigned long address = pvmw->address; 2844616b8371SZi Yan pmd_t pmdval; 2845616b8371SZi Yan swp_entry_t entry; 2846ab6e3d09SNaoya Horiguchi pmd_t pmdswp; 2847616b8371SZi Yan 2848616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 2849616b8371SZi Yan return; 2850616b8371SZi Yan 2851616b8371SZi Yan mmu_notifier_invalidate_range_start(mm, address, 2852616b8371SZi Yan address + HPAGE_PMD_SIZE); 2853616b8371SZi Yan 2854616b8371SZi Yan flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); 2855616b8371SZi Yan pmdval = *pvmw->pmd; 2856616b8371SZi Yan pmdp_invalidate(vma, address, pvmw->pmd); 2857616b8371SZi Yan if (pmd_dirty(pmdval)) 2858616b8371SZi Yan set_page_dirty(page); 2859616b8371SZi Yan entry = make_migration_entry(page, pmd_write(pmdval)); 2860ab6e3d09SNaoya Horiguchi pmdswp = swp_entry_to_pmd(entry); 2861ab6e3d09SNaoya Horiguchi if (pmd_soft_dirty(pmdval)) 2862ab6e3d09SNaoya Horiguchi pmdswp = pmd_swp_mksoft_dirty(pmdswp); 2863ab6e3d09SNaoya Horiguchi set_pmd_at(mm, address, pvmw->pmd, pmdswp); 2864616b8371SZi Yan page_remove_rmap(page, true); 2865616b8371SZi Yan put_page(page); 2866616b8371SZi Yan 2867616b8371SZi Yan mmu_notifier_invalidate_range_end(mm, address, 2868616b8371SZi Yan address + HPAGE_PMD_SIZE); 2869616b8371SZi Yan } 2870616b8371SZi Yan 2871616b8371SZi Yan void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 2872616b8371SZi Yan { 2873616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 2874616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 2875616b8371SZi Yan unsigned long address = pvmw->address; 2876616b8371SZi Yan unsigned long mmun_start = address & HPAGE_PMD_MASK; 2877616b8371SZi Yan pmd_t pmde; 2878616b8371SZi Yan swp_entry_t entry; 2879616b8371SZi Yan 2880616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 2881616b8371SZi Yan return; 2882616b8371SZi Yan 2883616b8371SZi Yan entry = pmd_to_swp_entry(*pvmw->pmd); 2884616b8371SZi Yan get_page(new); 2885616b8371SZi Yan pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); 2886ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pvmw->pmd)) 2887ab6e3d09SNaoya Horiguchi pmde = pmd_mksoft_dirty(pmde); 2888616b8371SZi Yan if (is_write_migration_entry(entry)) 2889616b8371SZi Yan pmde = maybe_pmd_mkwrite(pmde, vma); 2890616b8371SZi Yan 2891616b8371SZi Yan flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); 2892616b8371SZi Yan page_add_anon_rmap(new, vma, mmun_start, true); 2893616b8371SZi Yan set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); 2894616b8371SZi Yan if (vma->vm_flags & VM_LOCKED) 2895616b8371SZi Yan mlock_vma_page(new); 2896616b8371SZi Yan update_mmu_cache_pmd(vma, address, pvmw->pmd); 2897616b8371SZi Yan } 2898616b8371SZi Yan #endif 2899