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> 13*6a3827d7SIngo 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> 3597ae1749SKirill A. Shutemov 3671e3aac0SAndrea Arcangeli #include <asm/tlb.h> 3771e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 3871e3aac0SAndrea Arcangeli #include "internal.h" 3971e3aac0SAndrea Arcangeli 40ba76149fSAndrea Arcangeli /* 418bfa3f9aSJianguo Wu * By default transparent hugepage support is disabled in order that avoid 428bfa3f9aSJianguo Wu * to risk increase the memory footprint of applications without a guaranteed 438bfa3f9aSJianguo Wu * benefit. When transparent hugepage support is enabled, is for all mappings, 448bfa3f9aSJianguo Wu * and khugepaged scans all mappings. 458bfa3f9aSJianguo Wu * Defrag is invoked by khugepaged hugepage allocations and by page faults 468bfa3f9aSJianguo Wu * for all hugepage allocations. 47ba76149fSAndrea Arcangeli */ 4871e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 4913ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 50ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 5113ece886SAndrea Arcangeli #endif 5213ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 5313ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 5413ece886SAndrea Arcangeli #endif 55444eb2a4SMel Gorman (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| 5679da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 5779da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 58ba76149fSAndrea Arcangeli 599a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker; 60f000565aSAndrea Arcangeli 6197ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 6256873f43SWang, Yalin struct page *huge_zero_page __read_mostly; 634a6c1297SKirill A. Shutemov 646fcb52a5SAaron Lu static struct page *get_huge_zero_page(void) 6597ae1749SKirill A. Shutemov { 6697ae1749SKirill A. Shutemov struct page *zero_page; 6797ae1749SKirill A. Shutemov retry: 6897ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 694db0c3c2SJason Low return READ_ONCE(huge_zero_page); 7097ae1749SKirill A. Shutemov 7197ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 7297ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 73d8a8e1f0SKirill A. Shutemov if (!zero_page) { 74d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 755918d10aSKirill A. Shutemov return NULL; 76d8a8e1f0SKirill A. Shutemov } 77d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC); 7897ae1749SKirill A. Shutemov preempt_disable(); 795918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 8097ae1749SKirill A. Shutemov preempt_enable(); 815ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 8297ae1749SKirill A. Shutemov goto retry; 8397ae1749SKirill A. Shutemov } 8497ae1749SKirill A. Shutemov 8597ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 8697ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 8797ae1749SKirill A. Shutemov preempt_enable(); 884db0c3c2SJason Low return READ_ONCE(huge_zero_page); 8997ae1749SKirill A. Shutemov } 9097ae1749SKirill A. Shutemov 916fcb52a5SAaron Lu static void put_huge_zero_page(void) 9297ae1749SKirill A. Shutemov { 9397ae1749SKirill A. Shutemov /* 9497ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 9597ae1749SKirill A. Shutemov * last reference. 9697ae1749SKirill A. Shutemov */ 9797ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 9897ae1749SKirill A. Shutemov } 9997ae1749SKirill A. Shutemov 1006fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 1016fcb52a5SAaron Lu { 1026fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1036fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1046fcb52a5SAaron Lu 1056fcb52a5SAaron Lu if (!get_huge_zero_page()) 1066fcb52a5SAaron Lu return NULL; 1076fcb52a5SAaron Lu 1086fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1096fcb52a5SAaron Lu put_huge_zero_page(); 1106fcb52a5SAaron Lu 1116fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1126fcb52a5SAaron Lu } 1136fcb52a5SAaron Lu 1146fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 1156fcb52a5SAaron Lu { 1166fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1176fcb52a5SAaron Lu put_huge_zero_page(); 1186fcb52a5SAaron Lu } 1196fcb52a5SAaron Lu 12048896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 12197ae1749SKirill A. Shutemov struct shrink_control *sc) 12297ae1749SKirill A. Shutemov { 12397ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 12497ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 12548896466SGlauber Costa } 12697ae1749SKirill A. Shutemov 12748896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 12848896466SGlauber Costa struct shrink_control *sc) 12948896466SGlauber Costa { 13097ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 1315918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 1325918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 1335ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 13448896466SGlauber Costa return HPAGE_PMD_NR; 13597ae1749SKirill A. Shutemov } 13697ae1749SKirill A. Shutemov 13797ae1749SKirill A. Shutemov return 0; 13897ae1749SKirill A. Shutemov } 13997ae1749SKirill A. Shutemov 14097ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 14148896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 14248896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 14397ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 14497ae1749SKirill A. Shutemov }; 14597ae1749SKirill A. Shutemov 14671e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 14771e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 14871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 14971e3aac0SAndrea Arcangeli { 150444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 151444eb2a4SMel Gorman return sprintf(buf, "[always] madvise never\n"); 152444eb2a4SMel Gorman else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) 153444eb2a4SMel Gorman return sprintf(buf, "always [madvise] never\n"); 154444eb2a4SMel Gorman else 155444eb2a4SMel Gorman return sprintf(buf, "always madvise [never]\n"); 15671e3aac0SAndrea Arcangeli } 157444eb2a4SMel Gorman 15871e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 15971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 16071e3aac0SAndrea Arcangeli const char *buf, size_t count) 16171e3aac0SAndrea Arcangeli { 16221440d7eSDavid Rientjes ssize_t ret = count; 163ba76149fSAndrea Arcangeli 16421440d7eSDavid Rientjes if (!memcmp("always", buf, 16521440d7eSDavid Rientjes min(sizeof("always")-1, count))) { 16621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 16721440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 16821440d7eSDavid Rientjes } else if (!memcmp("madvise", buf, 16921440d7eSDavid Rientjes min(sizeof("madvise")-1, count))) { 17021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 17121440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 17221440d7eSDavid Rientjes } else if (!memcmp("never", buf, 17321440d7eSDavid Rientjes min(sizeof("never")-1, count))) { 17421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 17521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 17621440d7eSDavid Rientjes } else 17721440d7eSDavid Rientjes ret = -EINVAL; 178ba76149fSAndrea Arcangeli 179ba76149fSAndrea Arcangeli if (ret > 0) { 180b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 181ba76149fSAndrea Arcangeli if (err) 182ba76149fSAndrea Arcangeli ret = err; 183ba76149fSAndrea Arcangeli } 184ba76149fSAndrea Arcangeli return ret; 18571e3aac0SAndrea Arcangeli } 18671e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 18771e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 18871e3aac0SAndrea Arcangeli 189b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 19071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 19171e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 19271e3aac0SAndrea Arcangeli { 193e27e6151SBen Hutchings return sprintf(buf, "%d\n", 194e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 19571e3aac0SAndrea Arcangeli } 196e27e6151SBen Hutchings 197b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 19871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 19971e3aac0SAndrea Arcangeli const char *buf, size_t count, 20071e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 20171e3aac0SAndrea Arcangeli { 202e27e6151SBen Hutchings unsigned long value; 203e27e6151SBen Hutchings int ret; 204e27e6151SBen Hutchings 205e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 206e27e6151SBen Hutchings if (ret < 0) 207e27e6151SBen Hutchings return ret; 208e27e6151SBen Hutchings if (value > 1) 20971e3aac0SAndrea Arcangeli return -EINVAL; 21071e3aac0SAndrea Arcangeli 211e27e6151SBen Hutchings if (value) 212e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 213e27e6151SBen Hutchings else 214e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 215e27e6151SBen Hutchings 21671e3aac0SAndrea Arcangeli return count; 21771e3aac0SAndrea Arcangeli } 21871e3aac0SAndrea Arcangeli 21971e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 22071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 22171e3aac0SAndrea Arcangeli { 222444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 22321440d7eSDavid Rientjes return sprintf(buf, "[always] defer defer+madvise madvise never\n"); 224444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 22521440d7eSDavid Rientjes return sprintf(buf, "always [defer] defer+madvise madvise never\n"); 22621440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 22721440d7eSDavid Rientjes return sprintf(buf, "always defer [defer+madvise] madvise never\n"); 22821440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 22921440d7eSDavid Rientjes return sprintf(buf, "always defer defer+madvise [madvise] never\n"); 23021440d7eSDavid Rientjes return sprintf(buf, "always defer defer+madvise madvise [never]\n"); 23171e3aac0SAndrea Arcangeli } 23221440d7eSDavid Rientjes 23371e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 23471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 23571e3aac0SAndrea Arcangeli const char *buf, size_t count) 23671e3aac0SAndrea Arcangeli { 23721440d7eSDavid Rientjes if (!memcmp("always", buf, 23821440d7eSDavid Rientjes min(sizeof("always")-1, count))) { 23921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 24021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 24121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 24221440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 24321440d7eSDavid Rientjes } else if (!memcmp("defer", buf, 24421440d7eSDavid Rientjes min(sizeof("defer")-1, count))) { 24521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 24621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 24721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 24821440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 24921440d7eSDavid Rientjes } else if (!memcmp("defer+madvise", buf, 25021440d7eSDavid Rientjes min(sizeof("defer+madvise")-1, count))) { 25121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 25221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 25321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 25421440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 25521440d7eSDavid Rientjes } else if (!memcmp("madvise", buf, 25621440d7eSDavid Rientjes min(sizeof("madvise")-1, count))) { 25721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 25821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 25921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 26021440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 26121440d7eSDavid Rientjes } else if (!memcmp("never", buf, 26221440d7eSDavid Rientjes min(sizeof("never")-1, count))) { 26321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 26421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 26521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 26621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 26721440d7eSDavid Rientjes } else 26821440d7eSDavid Rientjes return -EINVAL; 26921440d7eSDavid Rientjes 27021440d7eSDavid Rientjes return count; 27171e3aac0SAndrea Arcangeli } 27271e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 27371e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 27471e3aac0SAndrea Arcangeli 27579da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 27679da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 27779da5407SKirill A. Shutemov { 278b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 27979da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 28079da5407SKirill A. Shutemov } 28179da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 28279da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 28379da5407SKirill A. Shutemov { 284b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 28579da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 28679da5407SKirill A. Shutemov } 28779da5407SKirill A. Shutemov static struct kobj_attribute use_zero_page_attr = 28879da5407SKirill A. Shutemov __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); 28949920d28SHugh Dickins 29049920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 29149920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 29249920d28SHugh Dickins { 29349920d28SHugh Dickins return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); 29449920d28SHugh Dickins } 29549920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 29649920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 29749920d28SHugh Dickins 29871e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 29971e3aac0SAndrea Arcangeli static ssize_t debug_cow_show(struct kobject *kobj, 30071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 30171e3aac0SAndrea Arcangeli { 302b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 30371e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 30471e3aac0SAndrea Arcangeli } 30571e3aac0SAndrea Arcangeli static ssize_t debug_cow_store(struct kobject *kobj, 30671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 30771e3aac0SAndrea Arcangeli const char *buf, size_t count) 30871e3aac0SAndrea Arcangeli { 309b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 31071e3aac0SAndrea Arcangeli TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); 31171e3aac0SAndrea Arcangeli } 31271e3aac0SAndrea Arcangeli static struct kobj_attribute debug_cow_attr = 31371e3aac0SAndrea Arcangeli __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); 31471e3aac0SAndrea Arcangeli #endif /* CONFIG_DEBUG_VM */ 31571e3aac0SAndrea Arcangeli 31671e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 31771e3aac0SAndrea Arcangeli &enabled_attr.attr, 31871e3aac0SAndrea Arcangeli &defrag_attr.attr, 31979da5407SKirill A. Shutemov &use_zero_page_attr.attr, 32049920d28SHugh Dickins &hpage_pmd_size_attr.attr, 321e496cf3dSKirill A. Shutemov #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) 3225a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 3235a6e75f8SKirill A. Shutemov #endif 32471e3aac0SAndrea Arcangeli #ifdef CONFIG_DEBUG_VM 32571e3aac0SAndrea Arcangeli &debug_cow_attr.attr, 32671e3aac0SAndrea Arcangeli #endif 32771e3aac0SAndrea Arcangeli NULL, 32871e3aac0SAndrea Arcangeli }; 32971e3aac0SAndrea Arcangeli 33071e3aac0SAndrea Arcangeli static struct attribute_group hugepage_attr_group = { 33171e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 332ba76149fSAndrea Arcangeli }; 333ba76149fSAndrea Arcangeli 334569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 335569e5590SShaohua Li { 336569e5590SShaohua Li int err; 337569e5590SShaohua Li 338569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 339569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 340ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 341569e5590SShaohua Li return -ENOMEM; 342569e5590SShaohua Li } 343569e5590SShaohua Li 344569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 345569e5590SShaohua Li if (err) { 346ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 347569e5590SShaohua Li goto delete_obj; 348569e5590SShaohua Li } 349569e5590SShaohua Li 350569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 351569e5590SShaohua Li if (err) { 352ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 353569e5590SShaohua Li goto remove_hp_group; 354569e5590SShaohua Li } 355569e5590SShaohua Li 356569e5590SShaohua Li return 0; 357569e5590SShaohua Li 358569e5590SShaohua Li remove_hp_group: 359569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 360569e5590SShaohua Li delete_obj: 361569e5590SShaohua Li kobject_put(*hugepage_kobj); 362569e5590SShaohua Li return err; 363569e5590SShaohua Li } 364569e5590SShaohua Li 365569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 366569e5590SShaohua Li { 367569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 368569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 369569e5590SShaohua Li kobject_put(hugepage_kobj); 370569e5590SShaohua Li } 371569e5590SShaohua Li #else 372569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 373569e5590SShaohua Li { 374569e5590SShaohua Li return 0; 375569e5590SShaohua Li } 376569e5590SShaohua Li 377569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 378569e5590SShaohua Li { 379569e5590SShaohua Li } 38071e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 38171e3aac0SAndrea Arcangeli 38271e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 38371e3aac0SAndrea Arcangeli { 38471e3aac0SAndrea Arcangeli int err; 385569e5590SShaohua Li struct kobject *hugepage_kobj; 38671e3aac0SAndrea Arcangeli 3874b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 3884b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 389569e5590SShaohua Li return -EINVAL; 3904b7167b9SAndrea Arcangeli } 3914b7167b9SAndrea Arcangeli 392ff20c2e0SKirill A. Shutemov /* 393ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 394ff20c2e0SKirill A. Shutemov */ 395ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); 396ff20c2e0SKirill A. Shutemov /* 397ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 398ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 399ff20c2e0SKirill A. Shutemov */ 400ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 401ff20c2e0SKirill A. Shutemov 402569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 403569e5590SShaohua Li if (err) 40465ebb64fSKirill A. Shutemov goto err_sysfs; 405ba76149fSAndrea Arcangeli 406b46e756fSKirill A. Shutemov err = khugepaged_init(); 407ba76149fSAndrea Arcangeli if (err) 40865ebb64fSKirill A. Shutemov goto err_slab; 409ba76149fSAndrea Arcangeli 41065ebb64fSKirill A. Shutemov err = register_shrinker(&huge_zero_page_shrinker); 41165ebb64fSKirill A. Shutemov if (err) 41265ebb64fSKirill A. Shutemov goto err_hzp_shrinker; 4139a982250SKirill A. Shutemov err = register_shrinker(&deferred_split_shrinker); 4149a982250SKirill A. Shutemov if (err) 4159a982250SKirill A. Shutemov goto err_split_shrinker; 41697ae1749SKirill A. Shutemov 41797562cd2SRik van Riel /* 41897562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 41997562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 42097562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 42197562cd2SRik van Riel */ 42279553da2SKirill A. Shutemov if (totalram_pages < (512 << (20 - PAGE_SHIFT))) { 42397562cd2SRik van Riel transparent_hugepage_flags = 0; 42479553da2SKirill A. Shutemov return 0; 42579553da2SKirill A. Shutemov } 42697562cd2SRik van Riel 42779553da2SKirill A. Shutemov err = start_stop_khugepaged(); 42865ebb64fSKirill A. Shutemov if (err) 42965ebb64fSKirill A. Shutemov goto err_khugepaged; 430ba76149fSAndrea Arcangeli 431569e5590SShaohua Li return 0; 43265ebb64fSKirill A. Shutemov err_khugepaged: 4339a982250SKirill A. Shutemov unregister_shrinker(&deferred_split_shrinker); 4349a982250SKirill A. Shutemov err_split_shrinker: 43565ebb64fSKirill A. Shutemov unregister_shrinker(&huge_zero_page_shrinker); 43665ebb64fSKirill A. Shutemov err_hzp_shrinker: 437b46e756fSKirill A. Shutemov khugepaged_destroy(); 43865ebb64fSKirill A. Shutemov err_slab: 439569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 44065ebb64fSKirill A. Shutemov err_sysfs: 441ba76149fSAndrea Arcangeli return err; 44271e3aac0SAndrea Arcangeli } 443a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 44471e3aac0SAndrea Arcangeli 44571e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 44671e3aac0SAndrea Arcangeli { 44771e3aac0SAndrea Arcangeli int ret = 0; 44871e3aac0SAndrea Arcangeli if (!str) 44971e3aac0SAndrea Arcangeli goto out; 45071e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 45171e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 45271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 45371e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 45471e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 45571e3aac0SAndrea Arcangeli ret = 1; 45671e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 45771e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 45871e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 45971e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 46071e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46171e3aac0SAndrea Arcangeli ret = 1; 46271e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 46371e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 46471e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46571e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 46671e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46771e3aac0SAndrea Arcangeli ret = 1; 46871e3aac0SAndrea Arcangeli } 46971e3aac0SAndrea Arcangeli out: 47071e3aac0SAndrea Arcangeli if (!ret) 471ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 47271e3aac0SAndrea Arcangeli return ret; 47371e3aac0SAndrea Arcangeli } 47471e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 47571e3aac0SAndrea Arcangeli 476b32967ffSMel Gorman pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 47771e3aac0SAndrea Arcangeli { 47871e3aac0SAndrea Arcangeli if (likely(vma->vm_flags & VM_WRITE)) 47971e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 48071e3aac0SAndrea Arcangeli return pmd; 48171e3aac0SAndrea Arcangeli } 48271e3aac0SAndrea Arcangeli 4839a982250SKirill A. Shutemov static inline struct list_head *page_deferred_list(struct page *page) 4849a982250SKirill A. Shutemov { 4859a982250SKirill A. Shutemov /* 4869a982250SKirill A. Shutemov * ->lru in the tail pages is occupied by compound_head. 4879a982250SKirill A. Shutemov * Let's use ->mapping + ->index in the second tail page as list_head. 4889a982250SKirill A. Shutemov */ 4899a982250SKirill A. Shutemov return (struct list_head *)&page[2].mapping; 4909a982250SKirill A. Shutemov } 4919a982250SKirill A. Shutemov 4929a982250SKirill A. Shutemov void prep_transhuge_page(struct page *page) 4939a982250SKirill A. Shutemov { 4949a982250SKirill A. Shutemov /* 4959a982250SKirill A. Shutemov * we use page->mapping and page->indexlru in second tail page 4969a982250SKirill A. Shutemov * as list_head: assuming THP order >= 2 4979a982250SKirill A. Shutemov */ 4989a982250SKirill A. Shutemov 4999a982250SKirill A. Shutemov INIT_LIST_HEAD(page_deferred_list(page)); 5009a982250SKirill A. Shutemov set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); 5019a982250SKirill A. Shutemov } 5029a982250SKirill A. Shutemov 50374d2fad1SToshi Kani unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len, 50474d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 50574d2fad1SToshi Kani { 50674d2fad1SToshi Kani unsigned long addr; 50774d2fad1SToshi Kani loff_t off_end = off + len; 50874d2fad1SToshi Kani loff_t off_align = round_up(off, size); 50974d2fad1SToshi Kani unsigned long len_pad; 51074d2fad1SToshi Kani 51174d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 51274d2fad1SToshi Kani return 0; 51374d2fad1SToshi Kani 51474d2fad1SToshi Kani len_pad = len + size; 51574d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 51674d2fad1SToshi Kani return 0; 51774d2fad1SToshi Kani 51874d2fad1SToshi Kani addr = current->mm->get_unmapped_area(filp, 0, len_pad, 51974d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 52074d2fad1SToshi Kani if (IS_ERR_VALUE(addr)) 52174d2fad1SToshi Kani return 0; 52274d2fad1SToshi Kani 52374d2fad1SToshi Kani addr += (off - addr) & (size - 1); 52474d2fad1SToshi Kani return addr; 52574d2fad1SToshi Kani } 52674d2fad1SToshi Kani 52774d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 52874d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 52974d2fad1SToshi Kani { 53074d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 53174d2fad1SToshi Kani 53274d2fad1SToshi Kani if (addr) 53374d2fad1SToshi Kani goto out; 53474d2fad1SToshi Kani if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) 53574d2fad1SToshi Kani goto out; 53674d2fad1SToshi Kani 53774d2fad1SToshi Kani addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); 53874d2fad1SToshi Kani if (addr) 53974d2fad1SToshi Kani return addr; 54074d2fad1SToshi Kani 54174d2fad1SToshi Kani out: 54274d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 54374d2fad1SToshi Kani } 54474d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 54574d2fad1SToshi Kani 54682b0f8c3SJan Kara static int __do_huge_pmd_anonymous_page(struct vm_fault *vmf, struct page *page, 547bae473a4SKirill A. Shutemov gfp_t gfp) 54871e3aac0SAndrea Arcangeli { 54982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 55000501b53SJohannes Weiner struct mem_cgroup *memcg; 55171e3aac0SAndrea Arcangeli pgtable_t pgtable; 55282b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 55371e3aac0SAndrea Arcangeli 554309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 55500501b53SJohannes Weiner 556bae473a4SKirill A. Shutemov if (mem_cgroup_try_charge(page, vma->vm_mm, gfp, &memcg, true)) { 5576b251fc9SAndrea Arcangeli put_page(page); 5586b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 5596b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 5606b251fc9SAndrea Arcangeli } 56171e3aac0SAndrea Arcangeli 562bae473a4SKirill A. Shutemov pgtable = pte_alloc_one(vma->vm_mm, haddr); 56300501b53SJohannes Weiner if (unlikely(!pgtable)) { 564f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, true); 5656b251fc9SAndrea Arcangeli put_page(page); 56600501b53SJohannes Weiner return VM_FAULT_OOM; 56700501b53SJohannes Weiner } 56800501b53SJohannes Weiner 56971e3aac0SAndrea Arcangeli clear_huge_page(page, haddr, HPAGE_PMD_NR); 57052f37629SMinchan Kim /* 57152f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 57252f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 57352f37629SMinchan Kim * write. 57452f37629SMinchan Kim */ 57571e3aac0SAndrea Arcangeli __SetPageUptodate(page); 57671e3aac0SAndrea Arcangeli 57782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 57882b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 57982b0f8c3SJan Kara spin_unlock(vmf->ptl); 580f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, true); 58171e3aac0SAndrea Arcangeli put_page(page); 582bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 58371e3aac0SAndrea Arcangeli } else { 58471e3aac0SAndrea Arcangeli pmd_t entry; 5856b251fc9SAndrea Arcangeli 5866b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 5876b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 5886b251fc9SAndrea Arcangeli int ret; 5896b251fc9SAndrea Arcangeli 59082b0f8c3SJan Kara spin_unlock(vmf->ptl); 591f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, true); 5926b251fc9SAndrea Arcangeli put_page(page); 593bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 59482b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 5956b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 5966b251fc9SAndrea Arcangeli return ret; 5976b251fc9SAndrea Arcangeli } 5986b251fc9SAndrea Arcangeli 5993122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 6003122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 601d281ee61SKirill A. Shutemov page_add_new_anon_rmap(page, vma, haddr, true); 602f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(page, memcg, false, true); 60300501b53SJohannes Weiner lru_cache_add_active_or_unevictable(page, vma); 60482b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 60582b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 606bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 607bae473a4SKirill A. Shutemov atomic_long_inc(&vma->vm_mm->nr_ptes); 60882b0f8c3SJan Kara spin_unlock(vmf->ptl); 6096b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 61071e3aac0SAndrea Arcangeli } 61171e3aac0SAndrea Arcangeli 612aa2e878eSDavid Rientjes return 0; 61371e3aac0SAndrea Arcangeli } 61471e3aac0SAndrea Arcangeli 615444eb2a4SMel Gorman /* 61621440d7eSDavid Rientjes * always: directly stall for all thp allocations 61721440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 61821440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 61921440d7eSDavid Rientjes * fail if not immediately available 62021440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 62121440d7eSDavid Rientjes * available 62221440d7eSDavid Rientjes * never: never stall for any thp allocation 623444eb2a4SMel Gorman */ 624444eb2a4SMel Gorman static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) 6250bbbc0b3SAndrea Arcangeli { 62621440d7eSDavid Rientjes const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); 627444eb2a4SMel Gorman 62821440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 62925160354SVlastimil Babka return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 63021440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 63121440d7eSDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 63221440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 63321440d7eSDavid Rientjes return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : 63421440d7eSDavid Rientjes __GFP_KSWAPD_RECLAIM); 63521440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 63621440d7eSDavid Rientjes return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : 63721440d7eSDavid Rientjes 0); 63825160354SVlastimil Babka return GFP_TRANSHUGE_LIGHT; 639444eb2a4SMel Gorman } 640444eb2a4SMel Gorman 641c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 642d295e341SKirill A. Shutemov static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 64397ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 6445918d10aSKirill A. Shutemov struct page *zero_page) 645fc9fe822SKirill A. Shutemov { 646fc9fe822SKirill A. Shutemov pmd_t entry; 6477c414164SAndrew Morton if (!pmd_none(*pmd)) 6487c414164SAndrew Morton return false; 6495918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 650fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 65112c9d70bSMatthew Wilcox if (pgtable) 6526b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 653fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 654e1f56c89SKirill A. Shutemov atomic_long_inc(&mm->nr_ptes); 6557c414164SAndrew Morton return true; 656fc9fe822SKirill A. Shutemov } 657fc9fe822SKirill A. Shutemov 65882b0f8c3SJan Kara int do_huge_pmd_anonymous_page(struct vm_fault *vmf) 65971e3aac0SAndrea Arcangeli { 66082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 661077fcf11SAneesh Kumar K.V gfp_t gfp; 66271e3aac0SAndrea Arcangeli struct page *page; 66382b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 66471e3aac0SAndrea Arcangeli 665128ec037SKirill A. Shutemov if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) 666c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 66771e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 66871e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 6696d50e60cSDavid Rientjes if (unlikely(khugepaged_enter(vma, vma->vm_flags))) 670ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 67182b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 672bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 67379da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 67480371957SKirill A. Shutemov pgtable_t pgtable; 6755918d10aSKirill A. Shutemov struct page *zero_page; 6763ea41e62SKirill A. Shutemov bool set; 6776b251fc9SAndrea Arcangeli int ret; 678bae473a4SKirill A. Shutemov pgtable = pte_alloc_one(vma->vm_mm, haddr); 67980371957SKirill A. Shutemov if (unlikely(!pgtable)) 68080371957SKirill A. Shutemov return VM_FAULT_OOM; 6816fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 6825918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 683bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 68497ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 685c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 68697ae1749SKirill A. Shutemov } 68782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 6886b251fc9SAndrea Arcangeli ret = 0; 6896b251fc9SAndrea Arcangeli set = false; 69082b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 6916b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 69282b0f8c3SJan Kara spin_unlock(vmf->ptl); 69382b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 6946b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 6956b251fc9SAndrea Arcangeli } else { 696bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 69782b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 69882b0f8c3SJan Kara spin_unlock(vmf->ptl); 6996b251fc9SAndrea Arcangeli set = true; 7006b251fc9SAndrea Arcangeli } 7016b251fc9SAndrea Arcangeli } else 70282b0f8c3SJan Kara spin_unlock(vmf->ptl); 7036fcb52a5SAaron Lu if (!set) 704bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 7056b251fc9SAndrea Arcangeli return ret; 70680371957SKirill A. Shutemov } 707444eb2a4SMel Gorman gfp = alloc_hugepage_direct_gfpmask(vma); 708077fcf11SAneesh Kumar K.V page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); 70981ab4201SAndi Kleen if (unlikely(!page)) { 71081ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 711c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 71281ab4201SAndi Kleen } 7139a982250SKirill A. Shutemov prep_transhuge_page(page); 71482b0f8c3SJan Kara return __do_huge_pmd_anonymous_page(vmf, page, gfp); 71571e3aac0SAndrea Arcangeli } 71671e3aac0SAndrea Arcangeli 717ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 718f25748e3SDan Williams pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write) 7195cad465dSMatthew Wilcox { 7205cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 7215cad465dSMatthew Wilcox pmd_t entry; 7225cad465dSMatthew Wilcox spinlock_t *ptl; 7235cad465dSMatthew Wilcox 7245cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 725f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 726f25748e3SDan Williams if (pfn_t_devmap(pfn)) 727f25748e3SDan Williams entry = pmd_mkdevmap(entry); 7285cad465dSMatthew Wilcox if (write) { 7295cad465dSMatthew Wilcox entry = pmd_mkyoung(pmd_mkdirty(entry)); 7305cad465dSMatthew Wilcox entry = maybe_pmd_mkwrite(entry, vma); 7315cad465dSMatthew Wilcox } 7325cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 7335cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 7345cad465dSMatthew Wilcox spin_unlock(ptl); 7355cad465dSMatthew Wilcox } 7365cad465dSMatthew Wilcox 7375cad465dSMatthew Wilcox int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 738f25748e3SDan Williams pmd_t *pmd, pfn_t pfn, bool write) 7395cad465dSMatthew Wilcox { 7405cad465dSMatthew Wilcox pgprot_t pgprot = vma->vm_page_prot; 7415cad465dSMatthew Wilcox /* 7425cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 7435cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 7445cad465dSMatthew Wilcox * can't support a 'special' bit. 7455cad465dSMatthew Wilcox */ 7465cad465dSMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 7475cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 7485cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 7495cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 750f25748e3SDan Williams BUG_ON(!pfn_t_devmap(pfn)); 7515cad465dSMatthew Wilcox 7525cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 7535cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 754308a047cSBorislav Petkov 755308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 756308a047cSBorislav Petkov 757ae18d6dcSMatthew Wilcox insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write); 758ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 7595cad465dSMatthew Wilcox } 760dee41079SDan Williams EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); 7615cad465dSMatthew Wilcox 762a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 763a00cc7d9SMatthew Wilcox static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 764a00cc7d9SMatthew Wilcox { 765a00cc7d9SMatthew Wilcox if (likely(vma->vm_flags & VM_WRITE)) 766a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 767a00cc7d9SMatthew Wilcox return pud; 768a00cc7d9SMatthew Wilcox } 769a00cc7d9SMatthew Wilcox 770a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 771a00cc7d9SMatthew Wilcox pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) 772a00cc7d9SMatthew Wilcox { 773a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 774a00cc7d9SMatthew Wilcox pud_t entry; 775a00cc7d9SMatthew Wilcox spinlock_t *ptl; 776a00cc7d9SMatthew Wilcox 777a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 778a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 779a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 780a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 781a00cc7d9SMatthew Wilcox if (write) { 782a00cc7d9SMatthew Wilcox entry = pud_mkyoung(pud_mkdirty(entry)); 783a00cc7d9SMatthew Wilcox entry = maybe_pud_mkwrite(entry, vma); 784a00cc7d9SMatthew Wilcox } 785a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 786a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 787a00cc7d9SMatthew Wilcox spin_unlock(ptl); 788a00cc7d9SMatthew Wilcox } 789a00cc7d9SMatthew Wilcox 790a00cc7d9SMatthew Wilcox int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 791a00cc7d9SMatthew Wilcox pud_t *pud, pfn_t pfn, bool write) 792a00cc7d9SMatthew Wilcox { 793a00cc7d9SMatthew Wilcox pgprot_t pgprot = vma->vm_page_prot; 794a00cc7d9SMatthew Wilcox /* 795a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 796a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 797a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 798a00cc7d9SMatthew Wilcox */ 799a00cc7d9SMatthew Wilcox BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 800a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 801a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 802a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 803a00cc7d9SMatthew Wilcox BUG_ON(!pfn_t_devmap(pfn)); 804a00cc7d9SMatthew Wilcox 805a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 806a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 807a00cc7d9SMatthew Wilcox 808a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 809a00cc7d9SMatthew Wilcox 810a00cc7d9SMatthew Wilcox insert_pfn_pud(vma, addr, pud, pfn, pgprot, write); 811a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 812a00cc7d9SMatthew Wilcox } 813a00cc7d9SMatthew Wilcox EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); 814a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 815a00cc7d9SMatthew Wilcox 8163565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 8173565fce3SDan Williams pmd_t *pmd) 8183565fce3SDan Williams { 8193565fce3SDan Williams pmd_t _pmd; 8203565fce3SDan Williams 8213565fce3SDan Williams /* 8223565fce3SDan Williams * We should set the dirty bit only for FOLL_WRITE but for now 8233565fce3SDan Williams * the dirty bit in the pmd is meaningless. And if the dirty 8243565fce3SDan Williams * bit will become meaningful and we'll only set it with 8253565fce3SDan Williams * FOLL_WRITE, an atomic set_bit will be required on the pmd to 8263565fce3SDan Williams * set the young bit, instead of the current set_pmd_at. 8273565fce3SDan Williams */ 8283565fce3SDan Williams _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); 8293565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 8303565fce3SDan Williams pmd, _pmd, 1)) 8313565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 8323565fce3SDan Williams } 8333565fce3SDan Williams 8343565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 8353565fce3SDan Williams pmd_t *pmd, int flags) 8363565fce3SDan Williams { 8373565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 8383565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 8393565fce3SDan Williams struct dev_pagemap *pgmap; 8403565fce3SDan Williams struct page *page; 8413565fce3SDan Williams 8423565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 8433565fce3SDan Williams 8448310d48bSKeno Fischer /* 8458310d48bSKeno Fischer * When we COW a devmap PMD entry, we split it into PTEs, so we should 8468310d48bSKeno Fischer * not be in this function with `flags & FOLL_COW` set. 8478310d48bSKeno Fischer */ 8488310d48bSKeno Fischer WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); 8498310d48bSKeno Fischer 8503565fce3SDan Williams if (flags & FOLL_WRITE && !pmd_write(*pmd)) 8513565fce3SDan Williams return NULL; 8523565fce3SDan Williams 8533565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 8543565fce3SDan Williams /* pass */; 8553565fce3SDan Williams else 8563565fce3SDan Williams return NULL; 8573565fce3SDan Williams 8583565fce3SDan Williams if (flags & FOLL_TOUCH) 8593565fce3SDan Williams touch_pmd(vma, addr, pmd); 8603565fce3SDan Williams 8613565fce3SDan Williams /* 8623565fce3SDan Williams * device mapped pages can only be returned if the 8633565fce3SDan Williams * caller will manage the page reference count. 8643565fce3SDan Williams */ 8653565fce3SDan Williams if (!(flags & FOLL_GET)) 8663565fce3SDan Williams return ERR_PTR(-EEXIST); 8673565fce3SDan Williams 8683565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 8693565fce3SDan Williams pgmap = get_dev_pagemap(pfn, NULL); 8703565fce3SDan Williams if (!pgmap) 8713565fce3SDan Williams return ERR_PTR(-EFAULT); 8723565fce3SDan Williams page = pfn_to_page(pfn); 8733565fce3SDan Williams get_page(page); 8743565fce3SDan Williams put_dev_pagemap(pgmap); 8753565fce3SDan Williams 8763565fce3SDan Williams return page; 8773565fce3SDan Williams } 8783565fce3SDan Williams 87971e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 88071e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 88171e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 88271e3aac0SAndrea Arcangeli { 883c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 88471e3aac0SAndrea Arcangeli struct page *src_page; 88571e3aac0SAndrea Arcangeli pmd_t pmd; 88612c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 887628d47ceSKirill A. Shutemov int ret = -ENOMEM; 88871e3aac0SAndrea Arcangeli 889628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 890628d47ceSKirill A. Shutemov if (!vma_is_anonymous(vma)) 891628d47ceSKirill A. Shutemov return 0; 892628d47ceSKirill A. Shutemov 89371e3aac0SAndrea Arcangeli pgtable = pte_alloc_one(dst_mm, addr); 89471e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 89571e3aac0SAndrea Arcangeli goto out; 89671e3aac0SAndrea Arcangeli 897c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 898c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 899c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 90071e3aac0SAndrea Arcangeli 90171e3aac0SAndrea Arcangeli ret = -EAGAIN; 90271e3aac0SAndrea Arcangeli pmd = *src_pmd; 903628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 90471e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 90571e3aac0SAndrea Arcangeli goto out_unlock; 90671e3aac0SAndrea Arcangeli } 907fc9fe822SKirill A. Shutemov /* 908c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 909fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 910fc9fe822SKirill A. Shutemov * a page table. 911fc9fe822SKirill A. Shutemov */ 912fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 9135918d10aSKirill A. Shutemov struct page *zero_page; 91497ae1749SKirill A. Shutemov /* 91597ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 91697ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 91797ae1749SKirill A. Shutemov * reference. 91897ae1749SKirill A. Shutemov */ 9196fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(dst_mm); 9206b251fc9SAndrea Arcangeli set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, 9215918d10aSKirill A. Shutemov zero_page); 922fc9fe822SKirill A. Shutemov ret = 0; 923fc9fe822SKirill A. Shutemov goto out_unlock; 924fc9fe822SKirill A. Shutemov } 925de466bd6SMel Gorman 92671e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 927309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 92871e3aac0SAndrea Arcangeli get_page(src_page); 92953f9263bSKirill A. Shutemov page_dup_rmap(src_page, true); 93071e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 9315c7fb56eSDan Williams atomic_long_inc(&dst_mm->nr_ptes); 9325c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 93371e3aac0SAndrea Arcangeli 93471e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 93571e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 93671e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 93771e3aac0SAndrea Arcangeli 93871e3aac0SAndrea Arcangeli ret = 0; 93971e3aac0SAndrea Arcangeli out_unlock: 940c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 941c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 94271e3aac0SAndrea Arcangeli out: 94371e3aac0SAndrea Arcangeli return ret; 94471e3aac0SAndrea Arcangeli } 94571e3aac0SAndrea Arcangeli 946a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 947a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 948a00cc7d9SMatthew Wilcox pud_t *pud) 949a00cc7d9SMatthew Wilcox { 950a00cc7d9SMatthew Wilcox pud_t _pud; 951a00cc7d9SMatthew Wilcox 952a00cc7d9SMatthew Wilcox /* 953a00cc7d9SMatthew Wilcox * We should set the dirty bit only for FOLL_WRITE but for now 954a00cc7d9SMatthew Wilcox * the dirty bit in the pud is meaningless. And if the dirty 955a00cc7d9SMatthew Wilcox * bit will become meaningful and we'll only set it with 956a00cc7d9SMatthew Wilcox * FOLL_WRITE, an atomic set_bit will be required on the pud to 957a00cc7d9SMatthew Wilcox * set the young bit, instead of the current set_pud_at. 958a00cc7d9SMatthew Wilcox */ 959a00cc7d9SMatthew Wilcox _pud = pud_mkyoung(pud_mkdirty(*pud)); 960a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 961a00cc7d9SMatthew Wilcox pud, _pud, 1)) 962a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 963a00cc7d9SMatthew Wilcox } 964a00cc7d9SMatthew Wilcox 965a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 966a00cc7d9SMatthew Wilcox pud_t *pud, int flags) 967a00cc7d9SMatthew Wilcox { 968a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 969a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 970a00cc7d9SMatthew Wilcox struct dev_pagemap *pgmap; 971a00cc7d9SMatthew Wilcox struct page *page; 972a00cc7d9SMatthew Wilcox 973a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 974a00cc7d9SMatthew Wilcox 975a00cc7d9SMatthew Wilcox if (flags & FOLL_WRITE && !pud_write(*pud)) 976a00cc7d9SMatthew Wilcox return NULL; 977a00cc7d9SMatthew Wilcox 978a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 979a00cc7d9SMatthew Wilcox /* pass */; 980a00cc7d9SMatthew Wilcox else 981a00cc7d9SMatthew Wilcox return NULL; 982a00cc7d9SMatthew Wilcox 983a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 984a00cc7d9SMatthew Wilcox touch_pud(vma, addr, pud); 985a00cc7d9SMatthew Wilcox 986a00cc7d9SMatthew Wilcox /* 987a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 988a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 989a00cc7d9SMatthew Wilcox */ 990a00cc7d9SMatthew Wilcox if (!(flags & FOLL_GET)) 991a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 992a00cc7d9SMatthew Wilcox 993a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 994a00cc7d9SMatthew Wilcox pgmap = get_dev_pagemap(pfn, NULL); 995a00cc7d9SMatthew Wilcox if (!pgmap) 996a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 997a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 998a00cc7d9SMatthew Wilcox get_page(page); 999a00cc7d9SMatthew Wilcox put_dev_pagemap(pgmap); 1000a00cc7d9SMatthew Wilcox 1001a00cc7d9SMatthew Wilcox return page; 1002a00cc7d9SMatthew Wilcox } 1003a00cc7d9SMatthew Wilcox 1004a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1005a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1006a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1007a00cc7d9SMatthew Wilcox { 1008a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1009a00cc7d9SMatthew Wilcox pud_t pud; 1010a00cc7d9SMatthew Wilcox int ret; 1011a00cc7d9SMatthew Wilcox 1012a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1013a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1014a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1015a00cc7d9SMatthew Wilcox 1016a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1017a00cc7d9SMatthew Wilcox pud = *src_pud; 1018a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1019a00cc7d9SMatthew Wilcox goto out_unlock; 1020a00cc7d9SMatthew Wilcox 1021a00cc7d9SMatthew Wilcox /* 1022a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1023a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1024a00cc7d9SMatthew Wilcox * a page table. 1025a00cc7d9SMatthew Wilcox */ 1026a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1027a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1028a00cc7d9SMatthew Wilcox } 1029a00cc7d9SMatthew Wilcox 1030a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1031a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1032a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1033a00cc7d9SMatthew Wilcox 1034a00cc7d9SMatthew Wilcox ret = 0; 1035a00cc7d9SMatthew Wilcox out_unlock: 1036a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1037a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1038a00cc7d9SMatthew Wilcox return ret; 1039a00cc7d9SMatthew Wilcox } 1040a00cc7d9SMatthew Wilcox 1041a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1042a00cc7d9SMatthew Wilcox { 1043a00cc7d9SMatthew Wilcox pud_t entry; 1044a00cc7d9SMatthew Wilcox unsigned long haddr; 1045a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1046a00cc7d9SMatthew Wilcox 1047a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1048a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1049a00cc7d9SMatthew Wilcox goto unlock; 1050a00cc7d9SMatthew Wilcox 1051a00cc7d9SMatthew Wilcox entry = pud_mkyoung(orig_pud); 1052a00cc7d9SMatthew Wilcox if (write) 1053a00cc7d9SMatthew Wilcox entry = pud_mkdirty(entry); 1054a00cc7d9SMatthew Wilcox haddr = vmf->address & HPAGE_PUD_MASK; 1055a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) 1056a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); 1057a00cc7d9SMatthew Wilcox 1058a00cc7d9SMatthew Wilcox unlock: 1059a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1060a00cc7d9SMatthew Wilcox } 1061a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1062a00cc7d9SMatthew Wilcox 106382b0f8c3SJan Kara void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) 1064a1dd450bSWill Deacon { 1065a1dd450bSWill Deacon pmd_t entry; 1066a1dd450bSWill Deacon unsigned long haddr; 106720f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1068a1dd450bSWill Deacon 106982b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 107082b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 1071a1dd450bSWill Deacon goto unlock; 1072a1dd450bSWill Deacon 1073a1dd450bSWill Deacon entry = pmd_mkyoung(orig_pmd); 107420f664aaSMinchan Kim if (write) 107520f664aaSMinchan Kim entry = pmd_mkdirty(entry); 107682b0f8c3SJan Kara haddr = vmf->address & HPAGE_PMD_MASK; 107720f664aaSMinchan Kim if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) 107882b0f8c3SJan Kara update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); 1079a1dd450bSWill Deacon 1080a1dd450bSWill Deacon unlock: 108182b0f8c3SJan Kara spin_unlock(vmf->ptl); 1082a1dd450bSWill Deacon } 1083a1dd450bSWill Deacon 108482b0f8c3SJan Kara static int do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, pmd_t orig_pmd, 1085bae473a4SKirill A. Shutemov struct page *page) 108671e3aac0SAndrea Arcangeli { 108782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 108882b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 108900501b53SJohannes Weiner struct mem_cgroup *memcg; 109071e3aac0SAndrea Arcangeli pgtable_t pgtable; 109171e3aac0SAndrea Arcangeli pmd_t _pmd; 109271e3aac0SAndrea Arcangeli int ret = 0, i; 109371e3aac0SAndrea Arcangeli struct page **pages; 10942ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 10952ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 109671e3aac0SAndrea Arcangeli 109771e3aac0SAndrea Arcangeli pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, 109871e3aac0SAndrea Arcangeli GFP_KERNEL); 109971e3aac0SAndrea Arcangeli if (unlikely(!pages)) { 110071e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 110171e3aac0SAndrea Arcangeli goto out; 110271e3aac0SAndrea Arcangeli } 110371e3aac0SAndrea Arcangeli 110471e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 110541b6167eSMichal Hocko pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, 110682b0f8c3SJan Kara vmf->address, page_to_nid(page)); 1107b9bbfbe3SAndrea Arcangeli if (unlikely(!pages[i] || 1108bae473a4SKirill A. Shutemov mem_cgroup_try_charge(pages[i], vma->vm_mm, 1109bae473a4SKirill A. Shutemov GFP_KERNEL, &memcg, false))) { 1110b9bbfbe3SAndrea Arcangeli if (pages[i]) 111171e3aac0SAndrea Arcangeli put_page(pages[i]); 1112b9bbfbe3SAndrea Arcangeli while (--i >= 0) { 111300501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 111400501b53SJohannes Weiner set_page_private(pages[i], 0); 1115f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(pages[i], memcg, 1116f627c2f5SKirill A. Shutemov false); 1117b9bbfbe3SAndrea Arcangeli put_page(pages[i]); 1118b9bbfbe3SAndrea Arcangeli } 111971e3aac0SAndrea Arcangeli kfree(pages); 112071e3aac0SAndrea Arcangeli ret |= VM_FAULT_OOM; 112171e3aac0SAndrea Arcangeli goto out; 112271e3aac0SAndrea Arcangeli } 112300501b53SJohannes Weiner set_page_private(pages[i], (unsigned long)memcg); 112471e3aac0SAndrea Arcangeli } 112571e3aac0SAndrea Arcangeli 112671e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 112771e3aac0SAndrea Arcangeli copy_user_highpage(pages[i], page + i, 11280089e485SHillf Danton haddr + PAGE_SIZE * i, vma); 112971e3aac0SAndrea Arcangeli __SetPageUptodate(pages[i]); 113071e3aac0SAndrea Arcangeli cond_resched(); 113171e3aac0SAndrea Arcangeli } 113271e3aac0SAndrea Arcangeli 11332ec74c3eSSagi Grimberg mmun_start = haddr; 11342ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 1135bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); 11362ec74c3eSSagi Grimberg 113782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 113882b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 113971e3aac0SAndrea Arcangeli goto out_free_pages; 1140309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 114171e3aac0SAndrea Arcangeli 114282b0f8c3SJan Kara pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); 114371e3aac0SAndrea Arcangeli /* leave pmd empty until pte is filled */ 114471e3aac0SAndrea Arcangeli 114582b0f8c3SJan Kara pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); 1146bae473a4SKirill A. Shutemov pmd_populate(vma->vm_mm, &_pmd, pgtable); 114771e3aac0SAndrea Arcangeli 114871e3aac0SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 1149bae473a4SKirill A. Shutemov pte_t entry; 115071e3aac0SAndrea Arcangeli entry = mk_pte(pages[i], vma->vm_page_prot); 115171e3aac0SAndrea Arcangeli entry = maybe_mkwrite(pte_mkdirty(entry), vma); 115200501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 115300501b53SJohannes Weiner set_page_private(pages[i], 0); 115482b0f8c3SJan Kara page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); 1155f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(pages[i], memcg, false, false); 115600501b53SJohannes Weiner lru_cache_add_active_or_unevictable(pages[i], vma); 115782b0f8c3SJan Kara vmf->pte = pte_offset_map(&_pmd, haddr); 115882b0f8c3SJan Kara VM_BUG_ON(!pte_none(*vmf->pte)); 115982b0f8c3SJan Kara set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); 116082b0f8c3SJan Kara pte_unmap(vmf->pte); 116171e3aac0SAndrea Arcangeli } 116271e3aac0SAndrea Arcangeli kfree(pages); 116371e3aac0SAndrea Arcangeli 116471e3aac0SAndrea Arcangeli smp_wmb(); /* make pte visible before pmd */ 116582b0f8c3SJan Kara pmd_populate(vma->vm_mm, vmf->pmd, pgtable); 1166d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 116782b0f8c3SJan Kara spin_unlock(vmf->ptl); 116871e3aac0SAndrea Arcangeli 1169bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); 11702ec74c3eSSagi Grimberg 117171e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 117271e3aac0SAndrea Arcangeli put_page(page); 117371e3aac0SAndrea Arcangeli 117471e3aac0SAndrea Arcangeli out: 117571e3aac0SAndrea Arcangeli return ret; 117671e3aac0SAndrea Arcangeli 117771e3aac0SAndrea Arcangeli out_free_pages: 117882b0f8c3SJan Kara spin_unlock(vmf->ptl); 1179bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); 1180b9bbfbe3SAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 118100501b53SJohannes Weiner memcg = (void *)page_private(pages[i]); 118200501b53SJohannes Weiner set_page_private(pages[i], 0); 1183f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(pages[i], memcg, false); 118471e3aac0SAndrea Arcangeli put_page(pages[i]); 1185b9bbfbe3SAndrea Arcangeli } 118671e3aac0SAndrea Arcangeli kfree(pages); 118771e3aac0SAndrea Arcangeli goto out; 118871e3aac0SAndrea Arcangeli } 118971e3aac0SAndrea Arcangeli 119082b0f8c3SJan Kara int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) 119171e3aac0SAndrea Arcangeli { 119282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 119393b4796dSKirill A. Shutemov struct page *page = NULL, *new_page; 119400501b53SJohannes Weiner struct mem_cgroup *memcg; 119582b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 11962ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 11972ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 11983b363692SMichal Hocko gfp_t huge_gfp; /* for allocation and charge */ 1199bae473a4SKirill A. Shutemov int ret = 0; 120071e3aac0SAndrea Arcangeli 120182b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 120281d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 120393b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 120493b4796dSKirill A. Shutemov goto alloc; 120582b0f8c3SJan Kara spin_lock(vmf->ptl); 120682b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 120771e3aac0SAndrea Arcangeli goto out_unlock; 120871e3aac0SAndrea Arcangeli 120971e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 1210309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); 12111f25fe20SKirill A. Shutemov /* 12121f25fe20SKirill A. Shutemov * We can only reuse the page if nobody else maps the huge page or it's 12136d0a07edSAndrea Arcangeli * part. 12141f25fe20SKirill A. Shutemov */ 12156d0a07edSAndrea Arcangeli if (page_trans_huge_mapcount(page, NULL) == 1) { 121671e3aac0SAndrea Arcangeli pmd_t entry; 121771e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 121871e3aac0SAndrea Arcangeli entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 121982b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 122082b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 122171e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 122271e3aac0SAndrea Arcangeli goto out_unlock; 122371e3aac0SAndrea Arcangeli } 1224ddc58f27SKirill A. Shutemov get_page(page); 122582b0f8c3SJan Kara spin_unlock(vmf->ptl); 122693b4796dSKirill A. Shutemov alloc: 122771e3aac0SAndrea Arcangeli if (transparent_hugepage_enabled(vma) && 1228077fcf11SAneesh Kumar K.V !transparent_hugepage_debug_cow()) { 1229444eb2a4SMel Gorman huge_gfp = alloc_hugepage_direct_gfpmask(vma); 12303b363692SMichal Hocko new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); 1231077fcf11SAneesh Kumar K.V } else 123271e3aac0SAndrea Arcangeli new_page = NULL; 123371e3aac0SAndrea Arcangeli 12349a982250SKirill A. Shutemov if (likely(new_page)) { 12359a982250SKirill A. Shutemov prep_transhuge_page(new_page); 12369a982250SKirill A. Shutemov } else { 1237eecc1e42SHugh Dickins if (!page) { 123882b0f8c3SJan Kara split_huge_pmd(vma, vmf->pmd, vmf->address); 1239e9b71ca9SKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 124093b4796dSKirill A. Shutemov } else { 124182b0f8c3SJan Kara ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); 12429845cbbdSKirill A. Shutemov if (ret & VM_FAULT_OOM) { 124382b0f8c3SJan Kara split_huge_pmd(vma, vmf->pmd, vmf->address); 12449845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 12459845cbbdSKirill A. Shutemov } 1246ddc58f27SKirill A. Shutemov put_page(page); 124793b4796dSKirill A. Shutemov } 124817766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 124971e3aac0SAndrea Arcangeli goto out; 125071e3aac0SAndrea Arcangeli } 125171e3aac0SAndrea Arcangeli 1252bae473a4SKirill A. Shutemov if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm, 1253bae473a4SKirill A. Shutemov huge_gfp, &memcg, true))) { 1254b9bbfbe3SAndrea Arcangeli put_page(new_page); 125582b0f8c3SJan Kara split_huge_pmd(vma, vmf->pmd, vmf->address); 1256bae473a4SKirill A. Shutemov if (page) 1257ddc58f27SKirill A. Shutemov put_page(page); 12589845cbbdSKirill A. Shutemov ret |= VM_FAULT_FALLBACK; 125917766ddeSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK); 1260b9bbfbe3SAndrea Arcangeli goto out; 1261b9bbfbe3SAndrea Arcangeli } 1262b9bbfbe3SAndrea Arcangeli 126317766ddeSDavid Rientjes count_vm_event(THP_FAULT_ALLOC); 126417766ddeSDavid Rientjes 1265eecc1e42SHugh Dickins if (!page) 126693b4796dSKirill A. Shutemov clear_huge_page(new_page, haddr, HPAGE_PMD_NR); 126793b4796dSKirill A. Shutemov else 126871e3aac0SAndrea Arcangeli copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); 126971e3aac0SAndrea Arcangeli __SetPageUptodate(new_page); 127071e3aac0SAndrea Arcangeli 12712ec74c3eSSagi Grimberg mmun_start = haddr; 12722ec74c3eSSagi Grimberg mmun_end = haddr + HPAGE_PMD_SIZE; 1273bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); 12742ec74c3eSSagi Grimberg 127582b0f8c3SJan Kara spin_lock(vmf->ptl); 127693b4796dSKirill A. Shutemov if (page) 1277ddc58f27SKirill A. Shutemov put_page(page); 127882b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 127982b0f8c3SJan Kara spin_unlock(vmf->ptl); 1280f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(new_page, memcg, true); 128171e3aac0SAndrea Arcangeli put_page(new_page); 12822ec74c3eSSagi Grimberg goto out_mn; 1283b9bbfbe3SAndrea Arcangeli } else { 128471e3aac0SAndrea Arcangeli pmd_t entry; 12853122359aSKirill A. Shutemov entry = mk_huge_pmd(new_page, vma->vm_page_prot); 12863122359aSKirill A. Shutemov entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 128782b0f8c3SJan Kara pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); 1288d281ee61SKirill A. Shutemov page_add_new_anon_rmap(new_page, vma, haddr, true); 1289f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(new_page, memcg, false, true); 129000501b53SJohannes Weiner lru_cache_add_active_or_unevictable(new_page, vma); 129182b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 129282b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1293eecc1e42SHugh Dickins if (!page) { 1294bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 129597ae1749SKirill A. Shutemov } else { 1296309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1297d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 129871e3aac0SAndrea Arcangeli put_page(page); 129993b4796dSKirill A. Shutemov } 130071e3aac0SAndrea Arcangeli ret |= VM_FAULT_WRITE; 130171e3aac0SAndrea Arcangeli } 130282b0f8c3SJan Kara spin_unlock(vmf->ptl); 13032ec74c3eSSagi Grimberg out_mn: 1304bae473a4SKirill A. Shutemov mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); 13052ec74c3eSSagi Grimberg out: 13062ec74c3eSSagi Grimberg return ret; 130771e3aac0SAndrea Arcangeli out_unlock: 130882b0f8c3SJan Kara spin_unlock(vmf->ptl); 130971e3aac0SAndrea Arcangeli return ret; 131071e3aac0SAndrea Arcangeli } 131171e3aac0SAndrea Arcangeli 13128310d48bSKeno Fischer /* 13138310d48bSKeno Fischer * FOLL_FORCE can write to even unwritable pmd's, but only 13148310d48bSKeno Fischer * after we've gone through a COW cycle and they are dirty. 13158310d48bSKeno Fischer */ 13168310d48bSKeno Fischer static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) 13178310d48bSKeno Fischer { 13188310d48bSKeno Fischer return pmd_write(pmd) || 13198310d48bSKeno Fischer ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); 13208310d48bSKeno Fischer } 13218310d48bSKeno Fischer 1322b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 132371e3aac0SAndrea Arcangeli unsigned long addr, 132471e3aac0SAndrea Arcangeli pmd_t *pmd, 132571e3aac0SAndrea Arcangeli unsigned int flags) 132671e3aac0SAndrea Arcangeli { 1327b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 132871e3aac0SAndrea Arcangeli struct page *page = NULL; 132971e3aac0SAndrea Arcangeli 1330c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 133171e3aac0SAndrea Arcangeli 13328310d48bSKeno Fischer if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) 133371e3aac0SAndrea Arcangeli goto out; 133471e3aac0SAndrea Arcangeli 133585facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 133685facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 133785facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 133885facf25SKirill A. Shutemov 13392b4847e7SMel Gorman /* Full NUMA hinting faults to serialise migration in fault paths */ 13408a0516edSMel Gorman if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) 13412b4847e7SMel Gorman goto out; 13422b4847e7SMel Gorman 134371e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 1344ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 13453565fce3SDan Williams if (flags & FOLL_TOUCH) 13463565fce3SDan Williams touch_pmd(vma, addr, pmd); 1347de60f5f1SEric B Munson if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { 1348e90309c9SKirill A. Shutemov /* 1349e90309c9SKirill A. Shutemov * We don't mlock() pte-mapped THPs. This way we can avoid 1350e90309c9SKirill A. Shutemov * leaking mlocked pages into non-VM_LOCKED VMAs. 1351e90309c9SKirill A. Shutemov * 13529a73f61bSKirill A. Shutemov * For anon THP: 13539a73f61bSKirill A. Shutemov * 1354e90309c9SKirill A. Shutemov * In most cases the pmd is the only mapping of the page as we 1355e90309c9SKirill A. Shutemov * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for 1356e90309c9SKirill A. Shutemov * writable private mappings in populate_vma_page_range(). 1357e90309c9SKirill A. Shutemov * 1358e90309c9SKirill A. Shutemov * The only scenario when we have the page shared here is if we 1359e90309c9SKirill A. Shutemov * mlocking read-only mapping shared over fork(). We skip 1360e90309c9SKirill A. Shutemov * mlocking such pages. 13619a73f61bSKirill A. Shutemov * 13629a73f61bSKirill A. Shutemov * For file THP: 13639a73f61bSKirill A. Shutemov * 13649a73f61bSKirill A. Shutemov * We can expect PageDoubleMap() to be stable under page lock: 13659a73f61bSKirill A. Shutemov * for file pages we set it in page_add_file_rmap(), which 13669a73f61bSKirill A. Shutemov * requires page to be locked. 1367e90309c9SKirill A. Shutemov */ 13689a73f61bSKirill A. Shutemov 13699a73f61bSKirill A. Shutemov if (PageAnon(page) && compound_mapcount(page) != 1) 13709a73f61bSKirill A. Shutemov goto skip_mlock; 13719a73f61bSKirill A. Shutemov if (PageDoubleMap(page) || !page->mapping) 13729a73f61bSKirill A. Shutemov goto skip_mlock; 13739a73f61bSKirill A. Shutemov if (!trylock_page(page)) 13749a73f61bSKirill A. Shutemov goto skip_mlock; 1375b676b293SDavid Rientjes lru_add_drain(); 13769a73f61bSKirill A. Shutemov if (page->mapping && !PageDoubleMap(page)) 1377b676b293SDavid Rientjes mlock_vma_page(page); 1378b676b293SDavid Rientjes unlock_page(page); 1379b676b293SDavid Rientjes } 13809a73f61bSKirill A. Shutemov skip_mlock: 138171e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1382ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 138371e3aac0SAndrea Arcangeli if (flags & FOLL_GET) 1384ddc58f27SKirill A. Shutemov get_page(page); 138571e3aac0SAndrea Arcangeli 138671e3aac0SAndrea Arcangeli out: 138771e3aac0SAndrea Arcangeli return page; 138871e3aac0SAndrea Arcangeli } 138971e3aac0SAndrea Arcangeli 1390d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 139182b0f8c3SJan Kara int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) 1392d10e63f2SMel Gorman { 139382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1394b8916634SMel Gorman struct anon_vma *anon_vma = NULL; 1395b32967ffSMel Gorman struct page *page; 139682b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 13978191acbdSMel Gorman int page_nid = -1, this_nid = numa_node_id(); 139890572890SPeter Zijlstra int target_nid, last_cpupid = -1; 13998191acbdSMel Gorman bool page_locked; 14008191acbdSMel Gorman bool migrated = false; 1401b191f9b1SMel Gorman bool was_writable; 14026688cc05SPeter Zijlstra int flags = 0; 1403d10e63f2SMel Gorman 140482b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 140582b0f8c3SJan Kara if (unlikely(!pmd_same(pmd, *vmf->pmd))) 1406d10e63f2SMel Gorman goto out_unlock; 1407d10e63f2SMel Gorman 1408de466bd6SMel Gorman /* 1409de466bd6SMel Gorman * If there are potential migrations, wait for completion and retry 1410de466bd6SMel Gorman * without disrupting NUMA hinting information. Do not relock and 1411de466bd6SMel Gorman * check_same as the page may no longer be mapped. 1412de466bd6SMel Gorman */ 141382b0f8c3SJan Kara if (unlikely(pmd_trans_migrating(*vmf->pmd))) { 141482b0f8c3SJan Kara page = pmd_page(*vmf->pmd); 141582b0f8c3SJan Kara spin_unlock(vmf->ptl); 14165d833062SMel Gorman wait_on_page_locked(page); 1417de466bd6SMel Gorman goto out; 1418de466bd6SMel Gorman } 1419de466bd6SMel Gorman 1420d10e63f2SMel Gorman page = pmd_page(pmd); 1421a1a46184SMel Gorman BUG_ON(is_huge_zero_page(page)); 14228191acbdSMel Gorman page_nid = page_to_nid(page); 142390572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 142403c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 142504bb2f94SRik van Riel if (page_nid == this_nid) { 142603c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 142704bb2f94SRik van Riel flags |= TNF_FAULT_LOCAL; 142804bb2f94SRik van Riel } 14294daae3b4SMel Gorman 1430bea66fbdSMel Gorman /* See similar comment in do_numa_page for explanation */ 1431288bc549SAneesh Kumar K.V if (!pmd_savedwrite(pmd)) 14326688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 14336688cc05SPeter Zijlstra 14346688cc05SPeter Zijlstra /* 1435ff9042b1SMel Gorman * Acquire the page lock to serialise THP migrations but avoid dropping 1436ff9042b1SMel Gorman * page_table_lock if at all possible 1437ff9042b1SMel Gorman */ 1438b8916634SMel Gorman page_locked = trylock_page(page); 1439b8916634SMel Gorman target_nid = mpol_misplaced(page, vma, haddr); 1440b8916634SMel Gorman if (target_nid == -1) { 1441b8916634SMel Gorman /* If the page was locked, there are no parallel migrations */ 1442a54a407fSMel Gorman if (page_locked) 1443b8916634SMel Gorman goto clear_pmdnuma; 14442b4847e7SMel Gorman } 1445cbee9f88SPeter Zijlstra 1446de466bd6SMel Gorman /* Migration could have started since the pmd_trans_migrating check */ 14472b4847e7SMel Gorman if (!page_locked) { 144882b0f8c3SJan Kara spin_unlock(vmf->ptl); 1449b8916634SMel Gorman wait_on_page_locked(page); 1450a54a407fSMel Gorman page_nid = -1; 1451b8916634SMel Gorman goto out; 1452b8916634SMel Gorman } 1453b8916634SMel Gorman 14542b4847e7SMel Gorman /* 14552b4847e7SMel Gorman * Page is misplaced. Page lock serialises migrations. Acquire anon_vma 14562b4847e7SMel Gorman * to serialises splits 14572b4847e7SMel Gorman */ 1458b8916634SMel Gorman get_page(page); 145982b0f8c3SJan Kara spin_unlock(vmf->ptl); 1460b8916634SMel Gorman anon_vma = page_lock_anon_vma_read(page); 1461b32967ffSMel Gorman 1462c69307d5SPeter Zijlstra /* Confirm the PMD did not change while page_table_lock was released */ 146382b0f8c3SJan Kara spin_lock(vmf->ptl); 146482b0f8c3SJan Kara if (unlikely(!pmd_same(pmd, *vmf->pmd))) { 1465b32967ffSMel Gorman unlock_page(page); 1466b32967ffSMel Gorman put_page(page); 1467a54a407fSMel Gorman page_nid = -1; 1468b32967ffSMel Gorman goto out_unlock; 1469b32967ffSMel Gorman } 1470ff9042b1SMel Gorman 1471c3a489caSMel Gorman /* Bail if we fail to protect against THP splits for any reason */ 1472c3a489caSMel Gorman if (unlikely(!anon_vma)) { 1473c3a489caSMel Gorman put_page(page); 1474c3a489caSMel Gorman page_nid = -1; 1475c3a489caSMel Gorman goto clear_pmdnuma; 1476c3a489caSMel Gorman } 1477c3a489caSMel Gorman 1478a54a407fSMel Gorman /* 1479a54a407fSMel Gorman * Migrate the THP to the requested node, returns with page unlocked 14808a0516edSMel Gorman * and access rights restored. 1481a54a407fSMel Gorman */ 148282b0f8c3SJan Kara spin_unlock(vmf->ptl); 1483bae473a4SKirill A. Shutemov migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, 148482b0f8c3SJan Kara vmf->pmd, pmd, vmf->address, page, target_nid); 14856688cc05SPeter Zijlstra if (migrated) { 14866688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 14878191acbdSMel Gorman page_nid = target_nid; 1488074c2381SMel Gorman } else 1489074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1490b32967ffSMel Gorman 14918191acbdSMel Gorman goto out; 14924daae3b4SMel Gorman clear_pmdnuma: 1493a54a407fSMel Gorman BUG_ON(!PageLocked(page)); 1494288bc549SAneesh Kumar K.V was_writable = pmd_savedwrite(pmd); 14954d942466SMel Gorman pmd = pmd_modify(pmd, vma->vm_page_prot); 1496b7b04004SMel Gorman pmd = pmd_mkyoung(pmd); 1497b191f9b1SMel Gorman if (was_writable) 1498b191f9b1SMel Gorman pmd = pmd_mkwrite(pmd); 149982b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 150082b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1501a54a407fSMel Gorman unlock_page(page); 1502d10e63f2SMel Gorman out_unlock: 150382b0f8c3SJan Kara spin_unlock(vmf->ptl); 1504b8916634SMel Gorman 1505b8916634SMel Gorman out: 1506b8916634SMel Gorman if (anon_vma) 1507b8916634SMel Gorman page_unlock_anon_vma_read(anon_vma); 1508b8916634SMel Gorman 15098191acbdSMel Gorman if (page_nid != -1) 151082b0f8c3SJan Kara task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, 15119a8b300fSAneesh Kumar K.V flags); 15128191acbdSMel Gorman 1513d10e63f2SMel Gorman return 0; 1514d10e63f2SMel Gorman } 1515d10e63f2SMel Gorman 1516319904adSHuang Ying /* 1517319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1518319904adSHuang Ying * Otherwise, return false. 1519319904adSHuang Ying */ 1520319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1521b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1522b8d3c4c3SMinchan Kim { 1523b8d3c4c3SMinchan Kim spinlock_t *ptl; 1524b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1525b8d3c4c3SMinchan Kim struct page *page; 1526b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1527319904adSHuang Ying bool ret = false; 1528b8d3c4c3SMinchan Kim 152907e32661SAneesh Kumar K.V tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); 153007e32661SAneesh Kumar K.V 1531b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1532b6ec57f4SKirill A. Shutemov if (!ptl) 153325eedabeSLinus Torvalds goto out_unlocked; 1534b8d3c4c3SMinchan Kim 1535b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1536319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1537b8d3c4c3SMinchan Kim goto out; 1538b8d3c4c3SMinchan Kim 1539b8d3c4c3SMinchan Kim page = pmd_page(orig_pmd); 1540b8d3c4c3SMinchan Kim /* 1541b8d3c4c3SMinchan Kim * If other processes are mapping this page, we couldn't discard 1542b8d3c4c3SMinchan Kim * the page unless they all do MADV_FREE so let's skip the page. 1543b8d3c4c3SMinchan Kim */ 1544b8d3c4c3SMinchan Kim if (page_mapcount(page) != 1) 1545b8d3c4c3SMinchan Kim goto out; 1546b8d3c4c3SMinchan Kim 1547b8d3c4c3SMinchan Kim if (!trylock_page(page)) 1548b8d3c4c3SMinchan Kim goto out; 1549b8d3c4c3SMinchan Kim 1550b8d3c4c3SMinchan Kim /* 1551b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1552b8d3c4c3SMinchan Kim * will deactivate only them. 1553b8d3c4c3SMinchan Kim */ 1554b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1555b8d3c4c3SMinchan Kim get_page(page); 1556b8d3c4c3SMinchan Kim spin_unlock(ptl); 15579818b8cdSHuang Ying split_huge_page(page); 1558b8d3c4c3SMinchan Kim put_page(page); 1559b8d3c4c3SMinchan Kim unlock_page(page); 1560b8d3c4c3SMinchan Kim goto out_unlocked; 1561b8d3c4c3SMinchan Kim } 1562b8d3c4c3SMinchan Kim 1563b8d3c4c3SMinchan Kim if (PageDirty(page)) 1564b8d3c4c3SMinchan Kim ClearPageDirty(page); 1565b8d3c4c3SMinchan Kim unlock_page(page); 1566b8d3c4c3SMinchan Kim 1567b8d3c4c3SMinchan Kim if (PageActive(page)) 1568b8d3c4c3SMinchan Kim deactivate_page(page); 1569b8d3c4c3SMinchan Kim 1570b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 1571b8d3c4c3SMinchan Kim orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, 1572b8d3c4c3SMinchan Kim tlb->fullmm); 1573b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1574b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1575b8d3c4c3SMinchan Kim 1576b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1577b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1578b8d3c4c3SMinchan Kim } 1579319904adSHuang Ying ret = true; 1580b8d3c4c3SMinchan Kim out: 1581b8d3c4c3SMinchan Kim spin_unlock(ptl); 1582b8d3c4c3SMinchan Kim out_unlocked: 1583b8d3c4c3SMinchan Kim return ret; 1584b8d3c4c3SMinchan Kim } 1585b8d3c4c3SMinchan Kim 1586953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1587953c66c2SAneesh Kumar K.V { 1588953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1589953c66c2SAneesh Kumar K.V 1590953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1591953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1592953c66c2SAneesh Kumar K.V atomic_long_dec(&mm->nr_ptes); 1593953c66c2SAneesh Kumar K.V } 1594953c66c2SAneesh Kumar K.V 159571e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1596f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 159771e3aac0SAndrea Arcangeli { 1598f5c8ad47SDavid Miller pmd_t orig_pmd; 1599da146769SKirill A. Shutemov spinlock_t *ptl; 1600da146769SKirill A. Shutemov 160107e32661SAneesh Kumar K.V tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); 160207e32661SAneesh Kumar K.V 1603b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1604b6ec57f4SKirill A. Shutemov if (!ptl) 1605da146769SKirill A. Shutemov return 0; 1606a6bf2bb0SAneesh Kumar K.V /* 1607a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 16088809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1609a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1610a6bf2bb0SAneesh Kumar K.V * operations. 1611a6bf2bb0SAneesh Kumar K.V */ 16128809aa2dSAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, 1613fcbe08d6SMartin Schwidefsky tlb->fullmm); 1614f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 16154897c765SMatthew Wilcox if (vma_is_dax(vma)) { 16164897c765SMatthew Wilcox spin_unlock(ptl); 1617da146769SKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 1618c0f2e176SAneesh Kumar K.V tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); 1619da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1620da146769SKirill A. Shutemov pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd)); 1621e1f56c89SKirill A. Shutemov atomic_long_dec(&tlb->mm->nr_ptes); 1622bf929152SKirill A. Shutemov spin_unlock(ptl); 1623c0f2e176SAneesh Kumar K.V tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); 1624479f0abbSKirill A. Shutemov } else { 16254897c765SMatthew Wilcox struct page *page = pmd_page(orig_pmd); 1626d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 1627309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1628309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1629b5072380SKirill A. Shutemov if (PageAnon(page)) { 1630b5072380SKirill A. Shutemov pgtable_t pgtable; 1631b5072380SKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); 1632b5072380SKirill A. Shutemov pte_free(tlb->mm, pgtable); 1633e1f56c89SKirill A. Shutemov atomic_long_dec(&tlb->mm->nr_ptes); 1634b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1635b5072380SKirill A. Shutemov } else { 1636953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1637953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1638b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR); 1639b5072380SKirill A. Shutemov } 1640bf929152SKirill A. Shutemov spin_unlock(ptl); 1641e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1642479f0abbSKirill A. Shutemov } 1643da146769SKirill A. Shutemov return 1; 164471e3aac0SAndrea Arcangeli } 164571e3aac0SAndrea Arcangeli 16461dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 16471dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 16481dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 16491dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 16501dd38b6cSAneesh Kumar K.V { 16511dd38b6cSAneesh Kumar K.V /* 16521dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 16531dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 16541dd38b6cSAneesh Kumar K.V * 16551dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 16561dd38b6cSAneesh Kumar K.V */ 16571dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 16581dd38b6cSAneesh Kumar K.V } 16591dd38b6cSAneesh Kumar K.V #endif 16601dd38b6cSAneesh Kumar K.V 1661bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 166237a1c49aSAndrea Arcangeli unsigned long new_addr, unsigned long old_end, 16635d190420SAaron Lu pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush) 166437a1c49aSAndrea Arcangeli { 1665bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 166637a1c49aSAndrea Arcangeli pmd_t pmd; 166737a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 16685d190420SAaron Lu bool force_flush = false; 166937a1c49aSAndrea Arcangeli 167037a1c49aSAndrea Arcangeli if ((old_addr & ~HPAGE_PMD_MASK) || 167137a1c49aSAndrea Arcangeli (new_addr & ~HPAGE_PMD_MASK) || 1672bf8616d5SHugh Dickins old_end - old_addr < HPAGE_PMD_SIZE) 16734b471e88SKirill A. Shutemov return false; 167437a1c49aSAndrea Arcangeli 167537a1c49aSAndrea Arcangeli /* 167637a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 167737a1c49aSAndrea Arcangeli * should have release it. 167837a1c49aSAndrea Arcangeli */ 167937a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 168037a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 16814b471e88SKirill A. Shutemov return false; 168237a1c49aSAndrea Arcangeli } 168337a1c49aSAndrea Arcangeli 1684bf929152SKirill A. Shutemov /* 1685bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1686bf929152SKirill A. Shutemov * ptlocks because exclusive mmap_sem prevents deadlock. 1687bf929152SKirill A. Shutemov */ 1688b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1689b6ec57f4SKirill A. Shutemov if (old_ptl) { 1690bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1691bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1692bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 16938809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1694a2ce2666SAaron Lu if (pmd_present(pmd) && pmd_dirty(pmd)) 1695a2ce2666SAaron Lu force_flush = true; 169637a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 16973592806cSKirill A. Shutemov 16981dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1699b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 17003592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 17013592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 17023592806cSKirill A. Shutemov } 1703b3084f4dSAneesh Kumar K.V set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); 1704b3084f4dSAneesh Kumar K.V if (new_ptl != old_ptl) 1705b3084f4dSAneesh Kumar K.V spin_unlock(new_ptl); 17065d190420SAaron Lu if (force_flush) 17075d190420SAaron Lu flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 17085d190420SAaron Lu else 17095d190420SAaron Lu *need_flush = true; 1710bf929152SKirill A. Shutemov spin_unlock(old_ptl); 17114b471e88SKirill A. Shutemov return true; 171237a1c49aSAndrea Arcangeli } 17134b471e88SKirill A. Shutemov return false; 171437a1c49aSAndrea Arcangeli } 171537a1c49aSAndrea Arcangeli 1716f123d74aSMel Gorman /* 1717f123d74aSMel Gorman * Returns 1718f123d74aSMel Gorman * - 0 if PMD could not be locked 1719f123d74aSMel Gorman * - 1 if PMD was locked but protections unchange and TLB flush unnecessary 1720f123d74aSMel Gorman * - HPAGE_PMD_NR is protections changed and TLB flush necessary 1721f123d74aSMel Gorman */ 1722cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 1723e944fd67SMel Gorman unsigned long addr, pgprot_t newprot, int prot_numa) 1724cd7548abSJohannes Weiner { 1725cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1726bf929152SKirill A. Shutemov spinlock_t *ptl; 1727cd7548abSJohannes Weiner int ret = 0; 1728cd7548abSJohannes Weiner 1729b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1730b6ec57f4SKirill A. Shutemov if (ptl) { 1731cd7548abSJohannes Weiner pmd_t entry; 1732b191f9b1SMel Gorman bool preserve_write = prot_numa && pmd_write(*pmd); 1733ba68bc01SMel Gorman ret = 1; 1734e944fd67SMel Gorman 1735e944fd67SMel Gorman /* 1736e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1737e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1738e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1739e944fd67SMel Gorman */ 1740e944fd67SMel Gorman if (prot_numa && is_huge_zero_pmd(*pmd)) { 1741e944fd67SMel Gorman spin_unlock(ptl); 1742ba68bc01SMel Gorman return ret; 1743e944fd67SMel Gorman } 1744e944fd67SMel Gorman 174510c1045fSMel Gorman if (!prot_numa || !pmd_protnone(*pmd)) { 17468809aa2dSAneesh Kumar K.V entry = pmdp_huge_get_and_clear_notify(mm, addr, pmd); 1747cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 1748b191f9b1SMel Gorman if (preserve_write) 1749288bc549SAneesh Kumar K.V entry = pmd_mk_savedwrite(entry); 1750f123d74aSMel Gorman ret = HPAGE_PMD_NR; 175156eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 1752b237adedSKirill A. Shutemov BUG_ON(vma_is_anonymous(vma) && !preserve_write && 1753b237adedSKirill A. Shutemov pmd_write(entry)); 175410c1045fSMel Gorman } 1755bf929152SKirill A. Shutemov spin_unlock(ptl); 1756cd7548abSJohannes Weiner } 1757cd7548abSJohannes Weiner 1758cd7548abSJohannes Weiner return ret; 1759cd7548abSJohannes Weiner } 1760cd7548abSJohannes Weiner 1761025c5b24SNaoya Horiguchi /* 17628f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 1763025c5b24SNaoya Horiguchi * 17648f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 17658f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 1766025c5b24SNaoya Horiguchi */ 1767b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1768025c5b24SNaoya Horiguchi { 1769b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 1770b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 17715c7fb56eSDan Williams if (likely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd))) 1772b6ec57f4SKirill A. Shutemov return ptl; 1773b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 1774b6ec57f4SKirill A. Shutemov return NULL; 1775025c5b24SNaoya Horiguchi } 1776025c5b24SNaoya Horiguchi 1777a00cc7d9SMatthew Wilcox /* 1778a00cc7d9SMatthew Wilcox * Returns true if a given pud maps a thp, false otherwise. 1779a00cc7d9SMatthew Wilcox * 1780a00cc7d9SMatthew Wilcox * Note that if it returns true, this routine returns without unlocking page 1781a00cc7d9SMatthew Wilcox * table lock. So callers must unlock it. 1782a00cc7d9SMatthew Wilcox */ 1783a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 1784a00cc7d9SMatthew Wilcox { 1785a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1786a00cc7d9SMatthew Wilcox 1787a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 1788a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 1789a00cc7d9SMatthew Wilcox return ptl; 1790a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1791a00cc7d9SMatthew Wilcox return NULL; 1792a00cc7d9SMatthew Wilcox } 1793a00cc7d9SMatthew Wilcox 1794a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1795a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 1796a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 1797a00cc7d9SMatthew Wilcox { 1798a00cc7d9SMatthew Wilcox pud_t orig_pud; 1799a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1800a00cc7d9SMatthew Wilcox 1801a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 1802a00cc7d9SMatthew Wilcox if (!ptl) 1803a00cc7d9SMatthew Wilcox return 0; 1804a00cc7d9SMatthew Wilcox /* 1805a00cc7d9SMatthew Wilcox * For architectures like ppc64 we look at deposited pgtable 1806a00cc7d9SMatthew Wilcox * when calling pudp_huge_get_and_clear. So do the 1807a00cc7d9SMatthew Wilcox * pgtable_trans_huge_withdraw after finishing pudp related 1808a00cc7d9SMatthew Wilcox * operations. 1809a00cc7d9SMatthew Wilcox */ 1810a00cc7d9SMatthew Wilcox orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, 1811a00cc7d9SMatthew Wilcox tlb->fullmm); 1812a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 1813a00cc7d9SMatthew Wilcox if (vma_is_dax(vma)) { 1814a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1815a00cc7d9SMatthew Wilcox /* No zero page support yet */ 1816a00cc7d9SMatthew Wilcox } else { 1817a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 1818a00cc7d9SMatthew Wilcox BUG(); 1819a00cc7d9SMatthew Wilcox } 1820a00cc7d9SMatthew Wilcox return 1; 1821a00cc7d9SMatthew Wilcox } 1822a00cc7d9SMatthew Wilcox 1823a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 1824a00cc7d9SMatthew Wilcox unsigned long haddr) 1825a00cc7d9SMatthew Wilcox { 1826a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 1827a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 1828a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 1829a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 1830a00cc7d9SMatthew Wilcox 1831a00cc7d9SMatthew Wilcox count_vm_event(THP_SPLIT_PMD); 1832a00cc7d9SMatthew Wilcox 1833a00cc7d9SMatthew Wilcox pudp_huge_clear_flush_notify(vma, haddr, pud); 1834a00cc7d9SMatthew Wilcox } 1835a00cc7d9SMatthew Wilcox 1836a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 1837a00cc7d9SMatthew Wilcox unsigned long address) 1838a00cc7d9SMatthew Wilcox { 1839a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1840a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1841a00cc7d9SMatthew Wilcox unsigned long haddr = address & HPAGE_PUD_MASK; 1842a00cc7d9SMatthew Wilcox 1843a00cc7d9SMatthew Wilcox mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PUD_SIZE); 1844a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 1845a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 1846a00cc7d9SMatthew Wilcox goto out; 1847a00cc7d9SMatthew Wilcox __split_huge_pud_locked(vma, pud, haddr); 1848a00cc7d9SMatthew Wilcox 1849a00cc7d9SMatthew Wilcox out: 1850a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1851a00cc7d9SMatthew Wilcox mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PUD_SIZE); 1852a00cc7d9SMatthew Wilcox } 1853a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1854a00cc7d9SMatthew Wilcox 1855eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 1856eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 1857eef1b3baSKirill A. Shutemov { 1858eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 1859eef1b3baSKirill A. Shutemov pgtable_t pgtable; 1860eef1b3baSKirill A. Shutemov pmd_t _pmd; 1861eef1b3baSKirill A. Shutemov int i; 1862eef1b3baSKirill A. Shutemov 1863eef1b3baSKirill A. Shutemov /* leave pmd empty until pte is filled */ 1864eef1b3baSKirill A. Shutemov pmdp_huge_clear_flush_notify(vma, haddr, pmd); 1865eef1b3baSKirill A. Shutemov 1866eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1867eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 1868eef1b3baSKirill A. Shutemov 1869eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 1870eef1b3baSKirill A. Shutemov pte_t *pte, entry; 1871eef1b3baSKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 1872eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 1873eef1b3baSKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 1874eef1b3baSKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 1875eef1b3baSKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 1876eef1b3baSKirill A. Shutemov pte_unmap(pte); 1877eef1b3baSKirill A. Shutemov } 1878eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 1879eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 1880eef1b3baSKirill A. Shutemov } 1881eef1b3baSKirill A. Shutemov 1882eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 1883ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 1884eef1b3baSKirill A. Shutemov { 1885eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 1886eef1b3baSKirill A. Shutemov struct page *page; 1887eef1b3baSKirill A. Shutemov pgtable_t pgtable; 1888eef1b3baSKirill A. Shutemov pmd_t _pmd; 1889804dd150SAndrea Arcangeli bool young, write, dirty, soft_dirty; 18902ac015e2SKirill A. Shutemov unsigned long addr; 1891eef1b3baSKirill A. Shutemov int i; 1892eef1b3baSKirill A. Shutemov 1893eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 1894eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 1895eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 18965c7fb56eSDan Williams VM_BUG_ON(!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)); 1897eef1b3baSKirill A. Shutemov 1898eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 1899eef1b3baSKirill A. Shutemov 1900d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 1901d21b9e57SKirill A. Shutemov _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); 1902953c66c2SAneesh Kumar K.V /* 1903953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 1904953c66c2SAneesh Kumar K.V * just go ahead and zap it 1905953c66c2SAneesh Kumar K.V */ 1906953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1907953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 1908d21b9e57SKirill A. Shutemov if (vma_is_dax(vma)) 1909d21b9e57SKirill A. Shutemov return; 1910d21b9e57SKirill A. Shutemov page = pmd_page(_pmd); 1911d21b9e57SKirill A. Shutemov if (!PageReferenced(page) && pmd_young(_pmd)) 1912d21b9e57SKirill A. Shutemov SetPageReferenced(page); 1913d21b9e57SKirill A. Shutemov page_remove_rmap(page, true); 1914d21b9e57SKirill A. Shutemov put_page(page); 1915d21b9e57SKirill A. Shutemov add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR); 1916eef1b3baSKirill A. Shutemov return; 1917eef1b3baSKirill A. Shutemov } else if (is_huge_zero_pmd(*pmd)) { 1918eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 1919eef1b3baSKirill A. Shutemov } 1920eef1b3baSKirill A. Shutemov 1921eef1b3baSKirill A. Shutemov page = pmd_page(*pmd); 1922eef1b3baSKirill A. Shutemov VM_BUG_ON_PAGE(!page_count(page), page); 1923fe896d18SJoonsoo Kim page_ref_add(page, HPAGE_PMD_NR - 1); 1924eef1b3baSKirill A. Shutemov write = pmd_write(*pmd); 1925eef1b3baSKirill A. Shutemov young = pmd_young(*pmd); 1926b8d3c4c3SMinchan Kim dirty = pmd_dirty(*pmd); 1927804dd150SAndrea Arcangeli soft_dirty = pmd_soft_dirty(*pmd); 1928eef1b3baSKirill A. Shutemov 1929c777e2a8SAneesh Kumar K.V pmdp_huge_split_prepare(vma, haddr, pmd); 1930eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1931eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 1932eef1b3baSKirill A. Shutemov 19332ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 1934eef1b3baSKirill A. Shutemov pte_t entry, *pte; 1935eef1b3baSKirill A. Shutemov /* 1936eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 1937eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 1938eef1b3baSKirill A. Shutemov * permissions across VMAs. 1939eef1b3baSKirill A. Shutemov */ 1940ba988280SKirill A. Shutemov if (freeze) { 1941ba988280SKirill A. Shutemov swp_entry_t swp_entry; 1942ba988280SKirill A. Shutemov swp_entry = make_migration_entry(page + i, write); 1943ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 1944804dd150SAndrea Arcangeli if (soft_dirty) 1945804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 1946ba988280SKirill A. Shutemov } else { 19476d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 1948b8d3c4c3SMinchan Kim entry = maybe_mkwrite(entry, vma); 1949eef1b3baSKirill A. Shutemov if (!write) 1950eef1b3baSKirill A. Shutemov entry = pte_wrprotect(entry); 1951eef1b3baSKirill A. Shutemov if (!young) 1952eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 1953804dd150SAndrea Arcangeli if (soft_dirty) 1954804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 1955ba988280SKirill A. Shutemov } 1956b8d3c4c3SMinchan Kim if (dirty) 1957b8d3c4c3SMinchan Kim SetPageDirty(page + i); 19582ac015e2SKirill A. Shutemov pte = pte_offset_map(&_pmd, addr); 1959eef1b3baSKirill A. Shutemov BUG_ON(!pte_none(*pte)); 19602ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 1961eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 1962eef1b3baSKirill A. Shutemov pte_unmap(pte); 1963eef1b3baSKirill A. Shutemov } 1964eef1b3baSKirill A. Shutemov 1965eef1b3baSKirill A. Shutemov /* 1966eef1b3baSKirill A. Shutemov * Set PG_double_map before dropping compound_mapcount to avoid 1967eef1b3baSKirill A. Shutemov * false-negative page_mapped(). 1968eef1b3baSKirill A. Shutemov */ 1969eef1b3baSKirill A. Shutemov if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { 1970eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 1971eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 1972eef1b3baSKirill A. Shutemov } 1973eef1b3baSKirill A. Shutemov 1974eef1b3baSKirill A. Shutemov if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { 1975eef1b3baSKirill A. Shutemov /* Last compound_mapcount is gone. */ 197611fb9989SMel Gorman __dec_node_page_state(page, NR_ANON_THPS); 1977eef1b3baSKirill A. Shutemov if (TestClearPageDoubleMap(page)) { 1978eef1b3baSKirill A. Shutemov /* No need in mapcount reference anymore */ 1979eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 1980eef1b3baSKirill A. Shutemov atomic_dec(&page[i]._mapcount); 1981eef1b3baSKirill A. Shutemov } 1982eef1b3baSKirill A. Shutemov } 1983eef1b3baSKirill A. Shutemov 1984eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 1985e9b61f19SKirill A. Shutemov /* 1986e9b61f19SKirill A. Shutemov * Up to this point the pmd is present and huge and userland has the 1987e9b61f19SKirill A. Shutemov * whole access to the hugepage during the split (which happens in 1988e9b61f19SKirill A. Shutemov * place). If we overwrite the pmd with the not-huge version pointing 1989e9b61f19SKirill A. Shutemov * to the pte here (which of course we could if all CPUs were bug 1990e9b61f19SKirill A. Shutemov * free), userland could trigger a small page size TLB miss on the 1991e9b61f19SKirill A. Shutemov * small sized TLB while the hugepage TLB entry is still established in 1992e9b61f19SKirill A. Shutemov * the huge TLB. Some CPU doesn't like that. 1993e9b61f19SKirill A. Shutemov * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum 1994e9b61f19SKirill A. Shutemov * 383 on page 93. Intel should be safe but is also warns that it's 1995e9b61f19SKirill A. Shutemov * only safe if the permission and cache attributes of the two entries 1996e9b61f19SKirill A. Shutemov * loaded in the two TLB is identical (which should be the case here). 1997e9b61f19SKirill A. Shutemov * But it is generally safer to never allow small and huge TLB entries 1998e9b61f19SKirill A. Shutemov * for the same virtual address to be loaded simultaneously. So instead 1999e9b61f19SKirill A. Shutemov * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2000e9b61f19SKirill A. Shutemov * current pmd notpresent (atomically because here the pmd_trans_huge 2001e9b61f19SKirill A. Shutemov * and pmd_trans_splitting must remain set at all times on the pmd 2002e9b61f19SKirill A. Shutemov * until the split is complete for this pmd), then we flush the SMP TLB 2003e9b61f19SKirill A. Shutemov * and finally we write the non-huge version of the pmd entry with 2004e9b61f19SKirill A. Shutemov * pmd_populate. 2005e9b61f19SKirill A. Shutemov */ 2006e9b61f19SKirill A. Shutemov pmdp_invalidate(vma, haddr, pmd); 2007eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2008e9b61f19SKirill A. Shutemov 2009e9b61f19SKirill A. Shutemov if (freeze) { 20102ac015e2SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) { 2011e9b61f19SKirill A. Shutemov page_remove_rmap(page + i, false); 2012e9b61f19SKirill A. Shutemov put_page(page + i); 2013e9b61f19SKirill A. Shutemov } 2014e9b61f19SKirill A. Shutemov } 2015eef1b3baSKirill A. Shutemov } 2016eef1b3baSKirill A. Shutemov 2017eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 201833f4751eSNaoya Horiguchi unsigned long address, bool freeze, struct page *page) 2019eef1b3baSKirill A. Shutemov { 2020eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2021eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2022eef1b3baSKirill A. Shutemov unsigned long haddr = address & HPAGE_PMD_MASK; 2023eef1b3baSKirill A. Shutemov 2024eef1b3baSKirill A. Shutemov mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE); 2025eef1b3baSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 202633f4751eSNaoya Horiguchi 202733f4751eSNaoya Horiguchi /* 202833f4751eSNaoya Horiguchi * If caller asks to setup a migration entries, we need a page to check 202933f4751eSNaoya Horiguchi * pmd against. Otherwise we can end up replacing wrong page. 203033f4751eSNaoya Horiguchi */ 203133f4751eSNaoya Horiguchi VM_BUG_ON(freeze && !page); 203233f4751eSNaoya Horiguchi if (page && page != pmd_page(*pmd)) 203333f4751eSNaoya Horiguchi goto out; 203433f4751eSNaoya Horiguchi 20355c7fb56eSDan Williams if (pmd_trans_huge(*pmd)) { 203633f4751eSNaoya Horiguchi page = pmd_page(*pmd); 2037e90309c9SKirill A. Shutemov if (PageMlocked(page)) 20385f737714SKirill A. Shutemov clear_page_mlock(page); 20395c7fb56eSDan Williams } else if (!pmd_devmap(*pmd)) 20405c7fb56eSDan Williams goto out; 2041fec89c10SKirill A. Shutemov __split_huge_pmd_locked(vma, pmd, haddr, freeze); 2042e90309c9SKirill A. Shutemov out: 2043eef1b3baSKirill A. Shutemov spin_unlock(ptl); 2044eef1b3baSKirill A. Shutemov mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE); 2045eef1b3baSKirill A. Shutemov } 2046eef1b3baSKirill A. Shutemov 2047fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2048fec89c10SKirill A. Shutemov bool freeze, struct page *page) 204994fcc585SAndrea Arcangeli { 2050f72e7dcdSHugh Dickins pgd_t *pgd; 2051f72e7dcdSHugh Dickins pud_t *pud; 205294fcc585SAndrea Arcangeli pmd_t *pmd; 205394fcc585SAndrea Arcangeli 205478ddc534SKirill A. Shutemov pgd = pgd_offset(vma->vm_mm, address); 2055f72e7dcdSHugh Dickins if (!pgd_present(*pgd)) 2056f72e7dcdSHugh Dickins return; 2057f72e7dcdSHugh Dickins 2058f72e7dcdSHugh Dickins pud = pud_offset(pgd, address); 2059f72e7dcdSHugh Dickins if (!pud_present(*pud)) 2060f72e7dcdSHugh Dickins return; 2061f72e7dcdSHugh Dickins 2062f72e7dcdSHugh Dickins pmd = pmd_offset(pud, address); 2063fec89c10SKirill A. Shutemov 206433f4751eSNaoya Horiguchi __split_huge_pmd(vma, pmd, address, freeze, page); 206594fcc585SAndrea Arcangeli } 206694fcc585SAndrea Arcangeli 2067e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 206894fcc585SAndrea Arcangeli unsigned long start, 206994fcc585SAndrea Arcangeli unsigned long end, 207094fcc585SAndrea Arcangeli long adjust_next) 207194fcc585SAndrea Arcangeli { 207294fcc585SAndrea Arcangeli /* 207394fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 207494fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 207594fcc585SAndrea Arcangeli * an huge pmd. 207694fcc585SAndrea Arcangeli */ 207794fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 207894fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 207994fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 2080fec89c10SKirill A. Shutemov split_huge_pmd_address(vma, start, false, NULL); 208194fcc585SAndrea Arcangeli 208294fcc585SAndrea Arcangeli /* 208394fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 208494fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 208594fcc585SAndrea Arcangeli * an huge pmd. 208694fcc585SAndrea Arcangeli */ 208794fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 208894fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 208994fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 2090fec89c10SKirill A. Shutemov split_huge_pmd_address(vma, end, false, NULL); 209194fcc585SAndrea Arcangeli 209294fcc585SAndrea Arcangeli /* 209394fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 209494fcc585SAndrea Arcangeli * vm_next->vm_start isn't page aligned and it could previously 209594fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 209694fcc585SAndrea Arcangeli */ 209794fcc585SAndrea Arcangeli if (adjust_next > 0) { 209894fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 209994fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 210094fcc585SAndrea Arcangeli nstart += adjust_next << PAGE_SHIFT; 210194fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 210294fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 210394fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 2104fec89c10SKirill A. Shutemov split_huge_pmd_address(next, nstart, false, NULL); 210594fcc585SAndrea Arcangeli } 210694fcc585SAndrea Arcangeli } 2107e9b61f19SKirill A. Shutemov 2108fec89c10SKirill A. Shutemov static void freeze_page(struct page *page) 2109e9b61f19SKirill A. Shutemov { 2110baa355fdSKirill A. Shutemov enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | 2111c7ab0d2fSKirill A. Shutemov TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; 2112c7ab0d2fSKirill A. Shutemov int ret; 2113e9b61f19SKirill A. Shutemov 2114e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageHead(page), page); 2115e9b61f19SKirill A. Shutemov 2116baa355fdSKirill A. Shutemov if (PageAnon(page)) 2117baa355fdSKirill A. Shutemov ttu_flags |= TTU_MIGRATION; 2118baa355fdSKirill A. Shutemov 2119c7ab0d2fSKirill A. Shutemov ret = try_to_unmap(page, ttu_flags); 2120c7ab0d2fSKirill A. Shutemov VM_BUG_ON_PAGE(ret, page); 2121bd56086fSKirill A. Shutemov } 2122bd56086fSKirill A. Shutemov 2123fec89c10SKirill A. Shutemov static void unfreeze_page(struct page *page) 2124e9b61f19SKirill A. Shutemov { 2125fec89c10SKirill A. Shutemov int i; 2126ace71a19SKirill A. Shutemov if (PageTransHuge(page)) { 2127ace71a19SKirill A. Shutemov remove_migration_ptes(page, page, true); 2128ace71a19SKirill A. Shutemov } else { 2129fec89c10SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2130fec89c10SKirill A. Shutemov remove_migration_ptes(page + i, page + i, true); 2131e9b61f19SKirill A. Shutemov } 2132ace71a19SKirill A. Shutemov } 2133e9b61f19SKirill A. Shutemov 21348df651c7SKirill A. Shutemov static void __split_huge_page_tail(struct page *head, int tail, 2135e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2136e9b61f19SKirill A. Shutemov { 2137e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 2138e9b61f19SKirill A. Shutemov 21398df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2140fe896d18SJoonsoo Kim VM_BUG_ON_PAGE(page_ref_count(page_tail) != 0, page_tail); 2141e9b61f19SKirill A. Shutemov 2142e9b61f19SKirill A. Shutemov /* 21430139aa7bSJoonsoo Kim * tail_page->_refcount is zero and not changing from under us. But 2144e9b61f19SKirill A. Shutemov * get_page_unless_zero() may be running from under us on the 2145baa355fdSKirill A. Shutemov * tail_page. If we used atomic_set() below instead of atomic_inc() or 2146baa355fdSKirill A. Shutemov * atomic_add(), we would then run atomic_set() concurrently with 2147e9b61f19SKirill A. Shutemov * get_page_unless_zero(), and atomic_set() is implemented in C not 2148e9b61f19SKirill A. Shutemov * using locked ops. spin_unlock on x86 sometime uses locked ops 2149e9b61f19SKirill A. Shutemov * because of PPro errata 66, 92, so unless somebody can guarantee 2150e9b61f19SKirill A. Shutemov * atomic_set() here would be safe on all archs (and not only on x86), 2151baa355fdSKirill A. Shutemov * it's safer to use atomic_inc()/atomic_add(). 2152e9b61f19SKirill A. Shutemov */ 2153baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2154fe896d18SJoonsoo Kim page_ref_inc(page_tail); 2155baa355fdSKirill A. Shutemov } else { 2156baa355fdSKirill A. Shutemov /* Additional pin to radix tree */ 2157baa355fdSKirill A. Shutemov page_ref_add(page_tail, 2); 2158baa355fdSKirill A. Shutemov } 2159e9b61f19SKirill A. Shutemov 2160e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2161e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2162e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2163e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 2164e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2165e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2166e9b61f19SKirill A. Shutemov (1L << PG_active) | 2167e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2168b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 2169b8d3c4c3SMinchan Kim (1L << PG_dirty))); 2170e9b61f19SKirill A. Shutemov 2171e9b61f19SKirill A. Shutemov /* 2172e9b61f19SKirill A. Shutemov * After clearing PageTail the gup refcount can be released. 2173e9b61f19SKirill A. Shutemov * Page flags also must be visible before we make the page non-compound. 2174e9b61f19SKirill A. Shutemov */ 2175e9b61f19SKirill A. Shutemov smp_wmb(); 2176e9b61f19SKirill A. Shutemov 2177e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2178e9b61f19SKirill A. Shutemov 2179e9b61f19SKirill A. Shutemov if (page_is_young(head)) 2180e9b61f19SKirill A. Shutemov set_page_young(page_tail); 2181e9b61f19SKirill A. Shutemov if (page_is_idle(head)) 2182e9b61f19SKirill A. Shutemov set_page_idle(page_tail); 2183e9b61f19SKirill A. Shutemov 2184e9b61f19SKirill A. Shutemov /* ->mapping in first tail page is compound_mapcount */ 21859a982250SKirill A. Shutemov VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2186e9b61f19SKirill A. Shutemov page_tail); 2187e9b61f19SKirill A. Shutemov page_tail->mapping = head->mapping; 2188e9b61f19SKirill A. Shutemov 2189e9b61f19SKirill A. Shutemov page_tail->index = head->index + tail; 2190e9b61f19SKirill A. Shutemov page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); 2191e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2192e9b61f19SKirill A. Shutemov } 2193e9b61f19SKirill A. Shutemov 2194baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2195baa355fdSKirill A. Shutemov unsigned long flags) 2196e9b61f19SKirill A. Shutemov { 2197e9b61f19SKirill A. Shutemov struct page *head = compound_head(page); 2198e9b61f19SKirill A. Shutemov struct zone *zone = page_zone(head); 2199e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 2200baa355fdSKirill A. Shutemov pgoff_t end = -1; 22018df651c7SKirill A. Shutemov int i; 2202e9b61f19SKirill A. Shutemov 2203599d0c95SMel Gorman lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat); 2204e9b61f19SKirill A. Shutemov 2205e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2206e9b61f19SKirill A. Shutemov mem_cgroup_split_huge_fixup(head); 2207e9b61f19SKirill A. Shutemov 2208baa355fdSKirill A. Shutemov if (!PageAnon(page)) 2209baa355fdSKirill A. Shutemov end = DIV_ROUND_UP(i_size_read(head->mapping->host), PAGE_SIZE); 2210baa355fdSKirill A. Shutemov 2211baa355fdSKirill A. Shutemov for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { 22128df651c7SKirill A. Shutemov __split_huge_page_tail(head, i, lruvec, list); 2213baa355fdSKirill A. Shutemov /* Some pages can be beyond i_size: drop them from page cache */ 2214baa355fdSKirill A. Shutemov if (head[i].index >= end) { 2215baa355fdSKirill A. Shutemov __ClearPageDirty(head + i); 2216baa355fdSKirill A. Shutemov __delete_from_page_cache(head + i, NULL); 2217800d8c63SKirill A. Shutemov if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) 2218800d8c63SKirill A. Shutemov shmem_uncharge(head->mapping->host, 1); 2219baa355fdSKirill A. Shutemov put_page(head + i); 2220baa355fdSKirill A. Shutemov } 2221baa355fdSKirill A. Shutemov } 2222e9b61f19SKirill A. Shutemov 2223e9b61f19SKirill A. Shutemov ClearPageCompound(head); 2224baa355fdSKirill A. Shutemov /* See comment in __split_huge_page_tail() */ 2225baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2226baa355fdSKirill A. Shutemov page_ref_inc(head); 2227baa355fdSKirill A. Shutemov } else { 2228baa355fdSKirill A. Shutemov /* Additional pin to radix tree */ 2229baa355fdSKirill A. Shutemov page_ref_add(head, 2); 2230baa355fdSKirill A. Shutemov spin_unlock(&head->mapping->tree_lock); 2231baa355fdSKirill A. Shutemov } 2232baa355fdSKirill A. Shutemov 2233a52633d8SMel Gorman spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); 2234e9b61f19SKirill A. Shutemov 2235fec89c10SKirill A. Shutemov unfreeze_page(head); 2236e9b61f19SKirill A. Shutemov 2237e9b61f19SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) { 2238e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2239e9b61f19SKirill A. Shutemov if (subpage == page) 2240e9b61f19SKirill A. Shutemov continue; 2241e9b61f19SKirill A. Shutemov unlock_page(subpage); 2242e9b61f19SKirill A. Shutemov 2243e9b61f19SKirill A. Shutemov /* 2244e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2245e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2246e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2247e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2248e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2249e9b61f19SKirill A. Shutemov */ 2250e9b61f19SKirill A. Shutemov put_page(subpage); 2251e9b61f19SKirill A. Shutemov } 2252e9b61f19SKirill A. Shutemov } 2253e9b61f19SKirill A. Shutemov 2254b20ce5e0SKirill A. Shutemov int total_mapcount(struct page *page) 2255b20ce5e0SKirill A. Shutemov { 2256dd78feddSKirill A. Shutemov int i, compound, ret; 2257b20ce5e0SKirill A. Shutemov 2258b20ce5e0SKirill A. Shutemov VM_BUG_ON_PAGE(PageTail(page), page); 2259b20ce5e0SKirill A. Shutemov 2260b20ce5e0SKirill A. Shutemov if (likely(!PageCompound(page))) 2261b20ce5e0SKirill A. Shutemov return atomic_read(&page->_mapcount) + 1; 2262b20ce5e0SKirill A. Shutemov 2263dd78feddSKirill A. Shutemov compound = compound_mapcount(page); 2264b20ce5e0SKirill A. Shutemov if (PageHuge(page)) 2265dd78feddSKirill A. Shutemov return compound; 2266dd78feddSKirill A. Shutemov ret = compound; 2267b20ce5e0SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2268b20ce5e0SKirill A. Shutemov ret += atomic_read(&page[i]._mapcount) + 1; 2269dd78feddSKirill A. Shutemov /* File pages has compound_mapcount included in _mapcount */ 2270dd78feddSKirill A. Shutemov if (!PageAnon(page)) 2271dd78feddSKirill A. Shutemov return ret - compound * HPAGE_PMD_NR; 2272b20ce5e0SKirill A. Shutemov if (PageDoubleMap(page)) 2273b20ce5e0SKirill A. Shutemov ret -= HPAGE_PMD_NR; 2274b20ce5e0SKirill A. Shutemov return ret; 2275b20ce5e0SKirill A. Shutemov } 2276b20ce5e0SKirill A. Shutemov 2277e9b61f19SKirill A. Shutemov /* 22786d0a07edSAndrea Arcangeli * This calculates accurately how many mappings a transparent hugepage 22796d0a07edSAndrea Arcangeli * has (unlike page_mapcount() which isn't fully accurate). This full 22806d0a07edSAndrea Arcangeli * accuracy is primarily needed to know if copy-on-write faults can 22816d0a07edSAndrea Arcangeli * reuse the page and change the mapping to read-write instead of 22826d0a07edSAndrea Arcangeli * copying them. At the same time this returns the total_mapcount too. 22836d0a07edSAndrea Arcangeli * 22846d0a07edSAndrea Arcangeli * The function returns the highest mapcount any one of the subpages 22856d0a07edSAndrea Arcangeli * has. If the return value is one, even if different processes are 22866d0a07edSAndrea Arcangeli * mapping different subpages of the transparent hugepage, they can 22876d0a07edSAndrea Arcangeli * all reuse it, because each process is reusing a different subpage. 22886d0a07edSAndrea Arcangeli * 22896d0a07edSAndrea Arcangeli * The total_mapcount is instead counting all virtual mappings of the 22906d0a07edSAndrea Arcangeli * subpages. If the total_mapcount is equal to "one", it tells the 22916d0a07edSAndrea Arcangeli * caller all mappings belong to the same "mm" and in turn the 22926d0a07edSAndrea Arcangeli * anon_vma of the transparent hugepage can become the vma->anon_vma 22936d0a07edSAndrea Arcangeli * local one as no other process may be mapping any of the subpages. 22946d0a07edSAndrea Arcangeli * 22956d0a07edSAndrea Arcangeli * It would be more accurate to replace page_mapcount() with 22966d0a07edSAndrea Arcangeli * page_trans_huge_mapcount(), however we only use 22976d0a07edSAndrea Arcangeli * page_trans_huge_mapcount() in the copy-on-write faults where we 22986d0a07edSAndrea Arcangeli * need full accuracy to avoid breaking page pinning, because 22996d0a07edSAndrea Arcangeli * page_trans_huge_mapcount() is slower than page_mapcount(). 23006d0a07edSAndrea Arcangeli */ 23016d0a07edSAndrea Arcangeli int page_trans_huge_mapcount(struct page *page, int *total_mapcount) 23026d0a07edSAndrea Arcangeli { 23036d0a07edSAndrea Arcangeli int i, ret, _total_mapcount, mapcount; 23046d0a07edSAndrea Arcangeli 23056d0a07edSAndrea Arcangeli /* hugetlbfs shouldn't call it */ 23066d0a07edSAndrea Arcangeli VM_BUG_ON_PAGE(PageHuge(page), page); 23076d0a07edSAndrea Arcangeli 23086d0a07edSAndrea Arcangeli if (likely(!PageTransCompound(page))) { 23096d0a07edSAndrea Arcangeli mapcount = atomic_read(&page->_mapcount) + 1; 23106d0a07edSAndrea Arcangeli if (total_mapcount) 23116d0a07edSAndrea Arcangeli *total_mapcount = mapcount; 23126d0a07edSAndrea Arcangeli return mapcount; 23136d0a07edSAndrea Arcangeli } 23146d0a07edSAndrea Arcangeli 23156d0a07edSAndrea Arcangeli page = compound_head(page); 23166d0a07edSAndrea Arcangeli 23176d0a07edSAndrea Arcangeli _total_mapcount = ret = 0; 23186d0a07edSAndrea Arcangeli for (i = 0; i < HPAGE_PMD_NR; i++) { 23196d0a07edSAndrea Arcangeli mapcount = atomic_read(&page[i]._mapcount) + 1; 23206d0a07edSAndrea Arcangeli ret = max(ret, mapcount); 23216d0a07edSAndrea Arcangeli _total_mapcount += mapcount; 23226d0a07edSAndrea Arcangeli } 23236d0a07edSAndrea Arcangeli if (PageDoubleMap(page)) { 23246d0a07edSAndrea Arcangeli ret -= 1; 23256d0a07edSAndrea Arcangeli _total_mapcount -= HPAGE_PMD_NR; 23266d0a07edSAndrea Arcangeli } 23276d0a07edSAndrea Arcangeli mapcount = compound_mapcount(page); 23286d0a07edSAndrea Arcangeli ret += mapcount; 23296d0a07edSAndrea Arcangeli _total_mapcount += mapcount; 23306d0a07edSAndrea Arcangeli if (total_mapcount) 23316d0a07edSAndrea Arcangeli *total_mapcount = _total_mapcount; 23326d0a07edSAndrea Arcangeli return ret; 23336d0a07edSAndrea Arcangeli } 23346d0a07edSAndrea Arcangeli 23356d0a07edSAndrea Arcangeli /* 2336e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2337e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2338e9b61f19SKirill A. Shutemov * 2339e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2340e9b61f19SKirill A. Shutemov * The huge page must be locked. 2341e9b61f19SKirill A. Shutemov * 2342e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2343e9b61f19SKirill A. Shutemov * 2344e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2345e9b61f19SKirill A. Shutemov * the hugepage. 2346e9b61f19SKirill A. Shutemov * 2347e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2348e9b61f19SKirill A. Shutemov * they are not mapped. 2349e9b61f19SKirill A. Shutemov * 2350e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2351e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2352e9b61f19SKirill A. Shutemov * us. 2353e9b61f19SKirill A. Shutemov */ 2354e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2355e9b61f19SKirill A. Shutemov { 2356e9b61f19SKirill A. Shutemov struct page *head = compound_head(page); 2357a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); 2358baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2359baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2360baa355fdSKirill A. Shutemov int count, mapcount, extra_pins, ret; 2361d9654322SKirill A. Shutemov bool mlocked; 23620b9b6fffSKirill A. Shutemov unsigned long flags; 2363e9b61f19SKirill A. Shutemov 2364e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(is_huge_zero_page(page), page); 2365e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2366e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageSwapBacked(page), page); 2367e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageCompound(page), page); 2368e9b61f19SKirill A. Shutemov 2369baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2370e9b61f19SKirill A. Shutemov /* 2371baa355fdSKirill A. Shutemov * The caller does not necessarily hold an mmap_sem that would 2372baa355fdSKirill A. Shutemov * prevent the anon_vma disappearing so we first we take a 2373baa355fdSKirill A. Shutemov * reference to it and then lock the anon_vma for write. This 2374baa355fdSKirill A. Shutemov * is similar to page_lock_anon_vma_read except the write lock 2375baa355fdSKirill A. Shutemov * is taken to serialise against parallel split or collapse 2376baa355fdSKirill A. Shutemov * operations. 2377e9b61f19SKirill A. Shutemov */ 2378e9b61f19SKirill A. Shutemov anon_vma = page_get_anon_vma(head); 2379e9b61f19SKirill A. Shutemov if (!anon_vma) { 2380e9b61f19SKirill A. Shutemov ret = -EBUSY; 2381e9b61f19SKirill A. Shutemov goto out; 2382e9b61f19SKirill A. Shutemov } 2383baa355fdSKirill A. Shutemov extra_pins = 0; 2384baa355fdSKirill A. Shutemov mapping = NULL; 2385e9b61f19SKirill A. Shutemov anon_vma_lock_write(anon_vma); 2386baa355fdSKirill A. Shutemov } else { 2387baa355fdSKirill A. Shutemov mapping = head->mapping; 2388baa355fdSKirill A. Shutemov 2389baa355fdSKirill A. Shutemov /* Truncated ? */ 2390baa355fdSKirill A. Shutemov if (!mapping) { 2391baa355fdSKirill A. Shutemov ret = -EBUSY; 2392baa355fdSKirill A. Shutemov goto out; 2393baa355fdSKirill A. Shutemov } 2394baa355fdSKirill A. Shutemov 2395baa355fdSKirill A. Shutemov /* Addidional pins from radix tree */ 2396baa355fdSKirill A. Shutemov extra_pins = HPAGE_PMD_NR; 2397baa355fdSKirill A. Shutemov anon_vma = NULL; 2398baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 2399baa355fdSKirill A. Shutemov } 2400e9b61f19SKirill A. Shutemov 2401e9b61f19SKirill A. Shutemov /* 2402e9b61f19SKirill A. Shutemov * Racy check if we can split the page, before freeze_page() will 2403e9b61f19SKirill A. Shutemov * split PMDs 2404e9b61f19SKirill A. Shutemov */ 2405baa355fdSKirill A. Shutemov if (total_mapcount(head) != page_count(head) - extra_pins - 1) { 2406e9b61f19SKirill A. Shutemov ret = -EBUSY; 2407e9b61f19SKirill A. Shutemov goto out_unlock; 2408e9b61f19SKirill A. Shutemov } 2409e9b61f19SKirill A. Shutemov 2410d9654322SKirill A. Shutemov mlocked = PageMlocked(page); 2411fec89c10SKirill A. Shutemov freeze_page(head); 2412e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(compound_mapcount(head), head); 2413e9b61f19SKirill A. Shutemov 2414d9654322SKirill A. Shutemov /* Make sure the page is not on per-CPU pagevec as it takes pin */ 2415d9654322SKirill A. Shutemov if (mlocked) 2416d9654322SKirill A. Shutemov lru_add_drain(); 2417d9654322SKirill A. Shutemov 2418baa355fdSKirill A. Shutemov /* prevent PageLRU to go away from under us, and freeze lru stats */ 2419a52633d8SMel Gorman spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags); 2420baa355fdSKirill A. Shutemov 2421baa355fdSKirill A. Shutemov if (mapping) { 2422baa355fdSKirill A. Shutemov void **pslot; 2423baa355fdSKirill A. Shutemov 2424baa355fdSKirill A. Shutemov spin_lock(&mapping->tree_lock); 2425baa355fdSKirill A. Shutemov pslot = radix_tree_lookup_slot(&mapping->page_tree, 2426baa355fdSKirill A. Shutemov page_index(head)); 2427baa355fdSKirill A. Shutemov /* 2428baa355fdSKirill A. Shutemov * Check if the head page is present in radix tree. 2429baa355fdSKirill A. Shutemov * We assume all tail are present too, if head is there. 2430baa355fdSKirill A. Shutemov */ 2431baa355fdSKirill A. Shutemov if (radix_tree_deref_slot_protected(pslot, 2432baa355fdSKirill A. Shutemov &mapping->tree_lock) != head) 2433baa355fdSKirill A. Shutemov goto fail; 2434baa355fdSKirill A. Shutemov } 2435baa355fdSKirill A. Shutemov 24360139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 2437baa355fdSKirill A. Shutemov spin_lock(&pgdata->split_queue_lock); 2438e9b61f19SKirill A. Shutemov count = page_count(head); 2439e9b61f19SKirill A. Shutemov mapcount = total_mapcount(head); 2440baa355fdSKirill A. Shutemov if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { 24419a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(head))) { 2442a3d0a918SKirill A. Shutemov pgdata->split_queue_len--; 24439a982250SKirill A. Shutemov list_del(page_deferred_list(head)); 24449a982250SKirill A. Shutemov } 244565c45377SKirill A. Shutemov if (mapping) 244611fb9989SMel Gorman __dec_node_page_state(page, NR_SHMEM_THPS); 2447baa355fdSKirill A. Shutemov spin_unlock(&pgdata->split_queue_lock); 2448baa355fdSKirill A. Shutemov __split_huge_page(page, list, flags); 2449e9b61f19SKirill A. Shutemov ret = 0; 2450baa355fdSKirill A. Shutemov } else { 2451baa355fdSKirill A. Shutemov if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { 2452e9b61f19SKirill A. Shutemov pr_alert("total_mapcount: %u, page_count(): %u\n", 2453e9b61f19SKirill A. Shutemov mapcount, count); 2454e9b61f19SKirill A. Shutemov if (PageTail(page)) 2455e9b61f19SKirill A. Shutemov dump_page(head, NULL); 2456bd56086fSKirill A. Shutemov dump_page(page, "total_mapcount(head) > 0"); 2457e9b61f19SKirill A. Shutemov BUG(); 2458baa355fdSKirill A. Shutemov } 2459baa355fdSKirill A. Shutemov spin_unlock(&pgdata->split_queue_lock); 2460baa355fdSKirill A. Shutemov fail: if (mapping) 2461baa355fdSKirill A. Shutemov spin_unlock(&mapping->tree_lock); 2462a52633d8SMel Gorman spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); 2463fec89c10SKirill A. Shutemov unfreeze_page(head); 2464e9b61f19SKirill A. Shutemov ret = -EBUSY; 2465e9b61f19SKirill A. Shutemov } 2466e9b61f19SKirill A. Shutemov 2467e9b61f19SKirill A. Shutemov out_unlock: 2468baa355fdSKirill A. Shutemov if (anon_vma) { 2469e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 2470e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 2471baa355fdSKirill A. Shutemov } 2472baa355fdSKirill A. Shutemov if (mapping) 2473baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 2474e9b61f19SKirill A. Shutemov out: 2475e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 2476e9b61f19SKirill A. Shutemov return ret; 2477e9b61f19SKirill A. Shutemov } 24789a982250SKirill A. Shutemov 24799a982250SKirill A. Shutemov void free_transhuge_page(struct page *page) 24809a982250SKirill A. Shutemov { 2481a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); 24829a982250SKirill A. Shutemov unsigned long flags; 24839a982250SKirill A. Shutemov 2484a3d0a918SKirill A. Shutemov spin_lock_irqsave(&pgdata->split_queue_lock, flags); 24859a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(page))) { 2486a3d0a918SKirill A. Shutemov pgdata->split_queue_len--; 24879a982250SKirill A. Shutemov list_del(page_deferred_list(page)); 24889a982250SKirill A. Shutemov } 2489a3d0a918SKirill A. Shutemov spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); 24909a982250SKirill A. Shutemov free_compound_page(page); 24919a982250SKirill A. Shutemov } 24929a982250SKirill A. Shutemov 24939a982250SKirill A. Shutemov void deferred_split_huge_page(struct page *page) 24949a982250SKirill A. Shutemov { 2495a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); 24969a982250SKirill A. Shutemov unsigned long flags; 24979a982250SKirill A. Shutemov 24989a982250SKirill A. Shutemov VM_BUG_ON_PAGE(!PageTransHuge(page), page); 24999a982250SKirill A. Shutemov 2500a3d0a918SKirill A. Shutemov spin_lock_irqsave(&pgdata->split_queue_lock, flags); 25019a982250SKirill A. Shutemov if (list_empty(page_deferred_list(page))) { 2502f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 2503a3d0a918SKirill A. Shutemov list_add_tail(page_deferred_list(page), &pgdata->split_queue); 2504a3d0a918SKirill A. Shutemov pgdata->split_queue_len++; 25059a982250SKirill A. Shutemov } 2506a3d0a918SKirill A. Shutemov spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); 25079a982250SKirill A. Shutemov } 25089a982250SKirill A. Shutemov 25099a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 25109a982250SKirill A. Shutemov struct shrink_control *sc) 25119a982250SKirill A. Shutemov { 2512a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2513cb8d68ecSKirill A. Shutemov return ACCESS_ONCE(pgdata->split_queue_len); 25149a982250SKirill A. Shutemov } 25159a982250SKirill A. Shutemov 25169a982250SKirill A. Shutemov static unsigned long deferred_split_scan(struct shrinker *shrink, 25179a982250SKirill A. Shutemov struct shrink_control *sc) 25189a982250SKirill A. Shutemov { 2519a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 25209a982250SKirill A. Shutemov unsigned long flags; 25219a982250SKirill A. Shutemov LIST_HEAD(list), *pos, *next; 25229a982250SKirill A. Shutemov struct page *page; 25239a982250SKirill A. Shutemov int split = 0; 25249a982250SKirill A. Shutemov 2525a3d0a918SKirill A. Shutemov spin_lock_irqsave(&pgdata->split_queue_lock, flags); 25269a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 2527ae026204SKirill A. Shutemov list_for_each_safe(pos, next, &pgdata->split_queue) { 25289a982250SKirill A. Shutemov page = list_entry((void *)pos, struct page, mapping); 25299a982250SKirill A. Shutemov page = compound_head(page); 2530e3ae1953SKirill A. Shutemov if (get_page_unless_zero(page)) { 2531e3ae1953SKirill A. Shutemov list_move(page_deferred_list(page), &list); 2532e3ae1953SKirill A. Shutemov } else { 2533e3ae1953SKirill A. Shutemov /* We lost race with put_compound_page() */ 25349a982250SKirill A. Shutemov list_del_init(page_deferred_list(page)); 2535a3d0a918SKirill A. Shutemov pgdata->split_queue_len--; 25369a982250SKirill A. Shutemov } 2537e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 2538e3ae1953SKirill A. Shutemov break; 25399a982250SKirill A. Shutemov } 2540a3d0a918SKirill A. Shutemov spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); 25419a982250SKirill A. Shutemov 25429a982250SKirill A. Shutemov list_for_each_safe(pos, next, &list) { 25439a982250SKirill A. Shutemov page = list_entry((void *)pos, struct page, mapping); 25449a982250SKirill A. Shutemov lock_page(page); 25459a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 25469a982250SKirill A. Shutemov if (!split_huge_page(page)) 25479a982250SKirill A. Shutemov split++; 25489a982250SKirill A. Shutemov unlock_page(page); 25499a982250SKirill A. Shutemov put_page(page); 25509a982250SKirill A. Shutemov } 25519a982250SKirill A. Shutemov 2552a3d0a918SKirill A. Shutemov spin_lock_irqsave(&pgdata->split_queue_lock, flags); 2553a3d0a918SKirill A. Shutemov list_splice_tail(&list, &pgdata->split_queue); 2554a3d0a918SKirill A. Shutemov spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); 25559a982250SKirill A. Shutemov 2556cb8d68ecSKirill A. Shutemov /* 2557cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 2558cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 2559cb8d68ecSKirill A. Shutemov */ 2560cb8d68ecSKirill A. Shutemov if (!split && list_empty(&pgdata->split_queue)) 2561cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 2562cb8d68ecSKirill A. Shutemov return split; 25639a982250SKirill A. Shutemov } 25649a982250SKirill A. Shutemov 25659a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker = { 25669a982250SKirill A. Shutemov .count_objects = deferred_split_count, 25679a982250SKirill A. Shutemov .scan_objects = deferred_split_scan, 25689a982250SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 2569a3d0a918SKirill A. Shutemov .flags = SHRINKER_NUMA_AWARE, 25709a982250SKirill A. Shutemov }; 257149071d43SKirill A. Shutemov 257249071d43SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 257349071d43SKirill A. Shutemov static int split_huge_pages_set(void *data, u64 val) 257449071d43SKirill A. Shutemov { 257549071d43SKirill A. Shutemov struct zone *zone; 257649071d43SKirill A. Shutemov struct page *page; 257749071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 257849071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 257949071d43SKirill A. Shutemov 258049071d43SKirill A. Shutemov if (val != 1) 258149071d43SKirill A. Shutemov return -EINVAL; 258249071d43SKirill A. Shutemov 258349071d43SKirill A. Shutemov for_each_populated_zone(zone) { 258449071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 258549071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 258649071d43SKirill A. Shutemov if (!pfn_valid(pfn)) 258749071d43SKirill A. Shutemov continue; 258849071d43SKirill A. Shutemov 258949071d43SKirill A. Shutemov page = pfn_to_page(pfn); 259049071d43SKirill A. Shutemov if (!get_page_unless_zero(page)) 259149071d43SKirill A. Shutemov continue; 259249071d43SKirill A. Shutemov 259349071d43SKirill A. Shutemov if (zone != page_zone(page)) 259449071d43SKirill A. Shutemov goto next; 259549071d43SKirill A. Shutemov 2596baa355fdSKirill A. Shutemov if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) 259749071d43SKirill A. Shutemov goto next; 259849071d43SKirill A. Shutemov 259949071d43SKirill A. Shutemov total++; 260049071d43SKirill A. Shutemov lock_page(page); 260149071d43SKirill A. Shutemov if (!split_huge_page(page)) 260249071d43SKirill A. Shutemov split++; 260349071d43SKirill A. Shutemov unlock_page(page); 260449071d43SKirill A. Shutemov next: 260549071d43SKirill A. Shutemov put_page(page); 260649071d43SKirill A. Shutemov } 260749071d43SKirill A. Shutemov } 260849071d43SKirill A. Shutemov 2609145bdaa1SYang Shi pr_info("%lu of %lu THP split\n", split, total); 261049071d43SKirill A. Shutemov 261149071d43SKirill A. Shutemov return 0; 261249071d43SKirill A. Shutemov } 261349071d43SKirill A. Shutemov DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, 261449071d43SKirill A. Shutemov "%llu\n"); 261549071d43SKirill A. Shutemov 261649071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 261749071d43SKirill A. Shutemov { 261849071d43SKirill A. Shutemov void *ret; 261949071d43SKirill A. Shutemov 2620145bdaa1SYang Shi ret = debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 262149071d43SKirill A. Shutemov &split_huge_pages_fops); 262249071d43SKirill A. Shutemov if (!ret) 262349071d43SKirill A. Shutemov pr_warn("Failed to create split_huge_pages in debugfs"); 262449071d43SKirill A. Shutemov return 0; 262549071d43SKirill A. Shutemov } 262649071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 262749071d43SKirill A. Shutemov #endif 2628