120c8ccb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 271e3aac0SAndrea Arcangeli /* 371e3aac0SAndrea Arcangeli * Copyright (C) 2009 Red Hat, Inc. 471e3aac0SAndrea Arcangeli */ 571e3aac0SAndrea Arcangeli 6ae3a8c1cSAndrew Morton #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 7ae3a8c1cSAndrew Morton 871e3aac0SAndrea Arcangeli #include <linux/mm.h> 971e3aac0SAndrea Arcangeli #include <linux/sched.h> 10f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 116a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 1271e3aac0SAndrea Arcangeli #include <linux/highmem.h> 1371e3aac0SAndrea Arcangeli #include <linux/hugetlb.h> 1471e3aac0SAndrea Arcangeli #include <linux/mmu_notifier.h> 1571e3aac0SAndrea Arcangeli #include <linux/rmap.h> 1671e3aac0SAndrea Arcangeli #include <linux/swap.h> 1797ae1749SKirill A. Shutemov #include <linux/shrinker.h> 18ba76149fSAndrea Arcangeli #include <linux/mm_inline.h> 19e9b61f19SKirill A. Shutemov #include <linux/swapops.h> 204897c765SMatthew Wilcox #include <linux/dax.h> 21ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 22878aee7dSAndrea Arcangeli #include <linux/freezer.h> 23f25748e3SDan Williams #include <linux/pfn_t.h> 24a664b2d8SAndrea Arcangeli #include <linux/mman.h> 253565fce3SDan Williams #include <linux/memremap.h> 26325adeb5SRalf Baechle #include <linux/pagemap.h> 2749071d43SKirill A. Shutemov #include <linux/debugfs.h> 284daae3b4SMel Gorman #include <linux/migrate.h> 2943b5fbbdSSasha Levin #include <linux/hashtable.h> 306b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 3133c3fc71SVladimir Davydov #include <linux/page_idle.h> 32baa355fdSKirill A. Shutemov #include <linux/shmem_fs.h> 336b31d595SMichal Hocko #include <linux/oom.h> 3498fa15f3SAnshuman Khandual #include <linux/numa.h> 35f7da677bSVlastimil Babka #include <linux/page_owner.h> 3697ae1749SKirill A. Shutemov 3771e3aac0SAndrea Arcangeli #include <asm/tlb.h> 3871e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 3971e3aac0SAndrea Arcangeli #include "internal.h" 4071e3aac0SAndrea Arcangeli 41ba76149fSAndrea Arcangeli /* 42b14d595aSMichael DeGuzis * By default, transparent hugepage support is disabled in order to avoid 43b14d595aSMichael DeGuzis * risking an increased memory footprint for applications that are not 44b14d595aSMichael DeGuzis * guaranteed to benefit from it. When transparent hugepage support is 45b14d595aSMichael DeGuzis * enabled, it is for all mappings, and khugepaged scans all mappings. 468bfa3f9aSJianguo Wu * Defrag is invoked by khugepaged hugepage allocations and by page faults 478bfa3f9aSJianguo Wu * for all hugepage allocations. 48ba76149fSAndrea Arcangeli */ 4971e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 5013ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 51ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 5213ece886SAndrea Arcangeli #endif 5313ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 5413ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 5513ece886SAndrea Arcangeli #endif 56444eb2a4SMel Gorman (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| 5779da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 5879da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 59ba76149fSAndrea Arcangeli 609a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker; 61f000565aSAndrea Arcangeli 6297ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 6356873f43SWang, Yalin struct page *huge_zero_page __read_mostly; 644a6c1297SKirill A. Shutemov 657635d9cbSMichal Hocko bool transparent_hugepage_enabled(struct vm_area_struct *vma) 667635d9cbSMichal Hocko { 67c0630669SYang Shi /* The addr is used to check if the vma size fits */ 68c0630669SYang Shi unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE; 69c0630669SYang Shi 70c0630669SYang Shi if (!transhuge_vma_suitable(vma, addr)) 71c0630669SYang Shi return false; 727635d9cbSMichal Hocko if (vma_is_anonymous(vma)) 737635d9cbSMichal Hocko return __transparent_hugepage_enabled(vma); 74c0630669SYang Shi if (vma_is_shmem(vma)) 75c0630669SYang Shi return shmem_huge_enabled(vma); 767635d9cbSMichal Hocko 777635d9cbSMichal Hocko return false; 787635d9cbSMichal Hocko } 797635d9cbSMichal Hocko 806fcb52a5SAaron Lu static struct page *get_huge_zero_page(void) 8197ae1749SKirill A. Shutemov { 8297ae1749SKirill A. Shutemov struct page *zero_page; 8397ae1749SKirill A. Shutemov retry: 8497ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 854db0c3c2SJason Low return READ_ONCE(huge_zero_page); 8697ae1749SKirill A. Shutemov 8797ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 8897ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 89d8a8e1f0SKirill A. Shutemov if (!zero_page) { 90d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 915918d10aSKirill A. Shutemov return NULL; 92d8a8e1f0SKirill A. Shutemov } 93d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC); 9497ae1749SKirill A. Shutemov preempt_disable(); 955918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 9697ae1749SKirill A. Shutemov preempt_enable(); 975ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 9897ae1749SKirill A. Shutemov goto retry; 9997ae1749SKirill A. Shutemov } 10097ae1749SKirill A. Shutemov 10197ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 10297ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 10397ae1749SKirill A. Shutemov preempt_enable(); 1044db0c3c2SJason Low return READ_ONCE(huge_zero_page); 10597ae1749SKirill A. Shutemov } 10697ae1749SKirill A. Shutemov 1076fcb52a5SAaron Lu static void put_huge_zero_page(void) 10897ae1749SKirill A. Shutemov { 10997ae1749SKirill A. Shutemov /* 11097ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 11197ae1749SKirill A. Shutemov * last reference. 11297ae1749SKirill A. Shutemov */ 11397ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 11497ae1749SKirill A. Shutemov } 11597ae1749SKirill A. Shutemov 1166fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 1176fcb52a5SAaron Lu { 1186fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1196fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1206fcb52a5SAaron Lu 1216fcb52a5SAaron Lu if (!get_huge_zero_page()) 1226fcb52a5SAaron Lu return NULL; 1236fcb52a5SAaron Lu 1246fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1256fcb52a5SAaron Lu put_huge_zero_page(); 1266fcb52a5SAaron Lu 1276fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1286fcb52a5SAaron Lu } 1296fcb52a5SAaron Lu 1306fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 1316fcb52a5SAaron Lu { 1326fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1336fcb52a5SAaron Lu put_huge_zero_page(); 1346fcb52a5SAaron Lu } 1356fcb52a5SAaron Lu 13648896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 13797ae1749SKirill A. Shutemov struct shrink_control *sc) 13897ae1749SKirill A. Shutemov { 13997ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 14097ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 14148896466SGlauber Costa } 14297ae1749SKirill A. Shutemov 14348896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 14448896466SGlauber Costa struct shrink_control *sc) 14548896466SGlauber Costa { 14697ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 1475918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 1485918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 1495ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 15048896466SGlauber Costa return HPAGE_PMD_NR; 15197ae1749SKirill A. Shutemov } 15297ae1749SKirill A. Shutemov 15397ae1749SKirill A. Shutemov return 0; 15497ae1749SKirill A. Shutemov } 15597ae1749SKirill A. Shutemov 15697ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 15748896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 15848896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 15997ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 16097ae1749SKirill A. Shutemov }; 16197ae1749SKirill A. Shutemov 16271e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 16371e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 16471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 16571e3aac0SAndrea Arcangeli { 166*bfb0ffebSJoe Perches const char *output; 167*bfb0ffebSJoe Perches 168444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 169*bfb0ffebSJoe Perches output = "[always] madvise never"; 170*bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 171*bfb0ffebSJoe Perches &transparent_hugepage_flags)) 172*bfb0ffebSJoe Perches output = "always [madvise] never"; 173444eb2a4SMel Gorman else 174*bfb0ffebSJoe Perches output = "always madvise [never]"; 175*bfb0ffebSJoe Perches 176*bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 17771e3aac0SAndrea Arcangeli } 178444eb2a4SMel Gorman 17971e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 18071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 18171e3aac0SAndrea Arcangeli const char *buf, size_t count) 18271e3aac0SAndrea Arcangeli { 18321440d7eSDavid Rientjes ssize_t ret = count; 184ba76149fSAndrea Arcangeli 185f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 18621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 18721440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 188f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 18921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 19021440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 191f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 19221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 19321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 19421440d7eSDavid Rientjes } else 19521440d7eSDavid Rientjes ret = -EINVAL; 196ba76149fSAndrea Arcangeli 197ba76149fSAndrea Arcangeli if (ret > 0) { 198b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 199ba76149fSAndrea Arcangeli if (err) 200ba76149fSAndrea Arcangeli ret = err; 201ba76149fSAndrea Arcangeli } 202ba76149fSAndrea Arcangeli return ret; 20371e3aac0SAndrea Arcangeli } 20471e3aac0SAndrea Arcangeli static struct kobj_attribute enabled_attr = 20571e3aac0SAndrea Arcangeli __ATTR(enabled, 0644, enabled_show, enabled_store); 20671e3aac0SAndrea Arcangeli 207b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 20871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 20971e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 21071e3aac0SAndrea Arcangeli { 211*bfb0ffebSJoe Perches return sysfs_emit(buf, "%d\n", 212e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 21371e3aac0SAndrea Arcangeli } 214e27e6151SBen Hutchings 215b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 21671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 21771e3aac0SAndrea Arcangeli const char *buf, size_t count, 21871e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 21971e3aac0SAndrea Arcangeli { 220e27e6151SBen Hutchings unsigned long value; 221e27e6151SBen Hutchings int ret; 222e27e6151SBen Hutchings 223e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 224e27e6151SBen Hutchings if (ret < 0) 225e27e6151SBen Hutchings return ret; 226e27e6151SBen Hutchings if (value > 1) 22771e3aac0SAndrea Arcangeli return -EINVAL; 22871e3aac0SAndrea Arcangeli 229e27e6151SBen Hutchings if (value) 230e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 231e27e6151SBen Hutchings else 232e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 233e27e6151SBen Hutchings 23471e3aac0SAndrea Arcangeli return count; 23571e3aac0SAndrea Arcangeli } 23671e3aac0SAndrea Arcangeli 23771e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 23871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 23971e3aac0SAndrea Arcangeli { 240*bfb0ffebSJoe Perches const char *output; 241*bfb0ffebSJoe Perches 242*bfb0ffebSJoe Perches if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, 243*bfb0ffebSJoe Perches &transparent_hugepage_flags)) 244*bfb0ffebSJoe Perches output = "[always] defer defer+madvise madvise never"; 245*bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, 246*bfb0ffebSJoe Perches &transparent_hugepage_flags)) 247*bfb0ffebSJoe Perches output = "always [defer] defer+madvise madvise never"; 248*bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, 249*bfb0ffebSJoe Perches &transparent_hugepage_flags)) 250*bfb0ffebSJoe Perches output = "always defer [defer+madvise] madvise never"; 251*bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, 252*bfb0ffebSJoe Perches &transparent_hugepage_flags)) 253*bfb0ffebSJoe Perches output = "always defer defer+madvise [madvise] never"; 254*bfb0ffebSJoe Perches else 255*bfb0ffebSJoe Perches output = "always defer defer+madvise madvise [never]"; 256*bfb0ffebSJoe Perches 257*bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 25871e3aac0SAndrea Arcangeli } 25921440d7eSDavid Rientjes 26071e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 26171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 26271e3aac0SAndrea Arcangeli const char *buf, size_t count) 26371e3aac0SAndrea Arcangeli { 264f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 26521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 26621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 26721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 26821440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 269f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer+madvise")) { 27021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 27121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 27221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 27321440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 274f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer")) { 2754fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 2764fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 2774fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 2784fad7fb6SDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 279f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 28021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 28121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 28221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 28321440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 284f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 28521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 28621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 28721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 28821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 28921440d7eSDavid Rientjes } else 29021440d7eSDavid Rientjes return -EINVAL; 29121440d7eSDavid Rientjes 29221440d7eSDavid Rientjes return count; 29371e3aac0SAndrea Arcangeli } 29471e3aac0SAndrea Arcangeli static struct kobj_attribute defrag_attr = 29571e3aac0SAndrea Arcangeli __ATTR(defrag, 0644, defrag_show, defrag_store); 29671e3aac0SAndrea Arcangeli 29779da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 29879da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 29979da5407SKirill A. Shutemov { 300b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 30179da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 30279da5407SKirill A. Shutemov } 30379da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 30479da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 30579da5407SKirill A. Shutemov { 306b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 30779da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 30879da5407SKirill A. Shutemov } 30979da5407SKirill A. Shutemov static struct kobj_attribute use_zero_page_attr = 31079da5407SKirill A. Shutemov __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); 31149920d28SHugh Dickins 31249920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 31349920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 31449920d28SHugh Dickins { 315ae7a927dSJoe Perches return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); 31649920d28SHugh Dickins } 31749920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 31849920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 31949920d28SHugh Dickins 32071e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 32171e3aac0SAndrea Arcangeli &enabled_attr.attr, 32271e3aac0SAndrea Arcangeli &defrag_attr.attr, 32379da5407SKirill A. Shutemov &use_zero_page_attr.attr, 32449920d28SHugh Dickins &hpage_pmd_size_attr.attr, 325396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_SHMEM 3265a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 3275a6e75f8SKirill A. Shutemov #endif 32871e3aac0SAndrea Arcangeli NULL, 32971e3aac0SAndrea Arcangeli }; 33071e3aac0SAndrea Arcangeli 3318aa95a21SArvind Yadav static const struct attribute_group hugepage_attr_group = { 33271e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 333ba76149fSAndrea Arcangeli }; 334ba76149fSAndrea Arcangeli 335569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 336569e5590SShaohua Li { 337569e5590SShaohua Li int err; 338569e5590SShaohua Li 339569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 340569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 341ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 342569e5590SShaohua Li return -ENOMEM; 343569e5590SShaohua Li } 344569e5590SShaohua Li 345569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 346569e5590SShaohua Li if (err) { 347ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 348569e5590SShaohua Li goto delete_obj; 349569e5590SShaohua Li } 350569e5590SShaohua Li 351569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 352569e5590SShaohua Li if (err) { 353ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 354569e5590SShaohua Li goto remove_hp_group; 355569e5590SShaohua Li } 356569e5590SShaohua Li 357569e5590SShaohua Li return 0; 358569e5590SShaohua Li 359569e5590SShaohua Li remove_hp_group: 360569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 361569e5590SShaohua Li delete_obj: 362569e5590SShaohua Li kobject_put(*hugepage_kobj); 363569e5590SShaohua Li return err; 364569e5590SShaohua Li } 365569e5590SShaohua Li 366569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 367569e5590SShaohua Li { 368569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 369569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 370569e5590SShaohua Li kobject_put(hugepage_kobj); 371569e5590SShaohua Li } 372569e5590SShaohua Li #else 373569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 374569e5590SShaohua Li { 375569e5590SShaohua Li return 0; 376569e5590SShaohua Li } 377569e5590SShaohua Li 378569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 379569e5590SShaohua Li { 380569e5590SShaohua Li } 38171e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 38271e3aac0SAndrea Arcangeli 38371e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 38471e3aac0SAndrea Arcangeli { 38571e3aac0SAndrea Arcangeli int err; 386569e5590SShaohua Li struct kobject *hugepage_kobj; 38771e3aac0SAndrea Arcangeli 3884b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 3894b7167b9SAndrea Arcangeli transparent_hugepage_flags = 0; 390569e5590SShaohua Li return -EINVAL; 3914b7167b9SAndrea Arcangeli } 3924b7167b9SAndrea Arcangeli 393ff20c2e0SKirill A. Shutemov /* 394ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 395ff20c2e0SKirill A. Shutemov */ 396ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); 397ff20c2e0SKirill A. Shutemov /* 398ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 399ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 400ff20c2e0SKirill A. Shutemov */ 401ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 402ff20c2e0SKirill A. Shutemov 403569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 404569e5590SShaohua Li if (err) 40565ebb64fSKirill A. Shutemov goto err_sysfs; 406ba76149fSAndrea Arcangeli 407b46e756fSKirill A. Shutemov err = khugepaged_init(); 408ba76149fSAndrea Arcangeli if (err) 40965ebb64fSKirill A. Shutemov goto err_slab; 410ba76149fSAndrea Arcangeli 41165ebb64fSKirill A. Shutemov err = register_shrinker(&huge_zero_page_shrinker); 41265ebb64fSKirill A. Shutemov if (err) 41365ebb64fSKirill A. Shutemov goto err_hzp_shrinker; 4149a982250SKirill A. Shutemov err = register_shrinker(&deferred_split_shrinker); 4159a982250SKirill A. Shutemov if (err) 4169a982250SKirill A. Shutemov goto err_split_shrinker; 41797ae1749SKirill A. Shutemov 41897562cd2SRik van Riel /* 41997562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 42097562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 42197562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 42297562cd2SRik van Riel */ 423ca79b0c2SArun KS if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { 42497562cd2SRik van Riel transparent_hugepage_flags = 0; 42579553da2SKirill A. Shutemov return 0; 42679553da2SKirill A. Shutemov } 42797562cd2SRik van Riel 42879553da2SKirill A. Shutemov err = start_stop_khugepaged(); 42965ebb64fSKirill A. Shutemov if (err) 43065ebb64fSKirill A. Shutemov goto err_khugepaged; 431ba76149fSAndrea Arcangeli 432569e5590SShaohua Li return 0; 43365ebb64fSKirill A. Shutemov err_khugepaged: 4349a982250SKirill A. Shutemov unregister_shrinker(&deferred_split_shrinker); 4359a982250SKirill A. Shutemov err_split_shrinker: 43665ebb64fSKirill A. Shutemov unregister_shrinker(&huge_zero_page_shrinker); 43765ebb64fSKirill A. Shutemov err_hzp_shrinker: 438b46e756fSKirill A. Shutemov khugepaged_destroy(); 43965ebb64fSKirill A. Shutemov err_slab: 440569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 44165ebb64fSKirill A. Shutemov err_sysfs: 442ba76149fSAndrea Arcangeli return err; 44371e3aac0SAndrea Arcangeli } 444a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 44571e3aac0SAndrea Arcangeli 44671e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 44771e3aac0SAndrea Arcangeli { 44871e3aac0SAndrea Arcangeli int ret = 0; 44971e3aac0SAndrea Arcangeli if (!str) 45071e3aac0SAndrea Arcangeli goto out; 45171e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 45271e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 45371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 45471e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 45571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 45671e3aac0SAndrea Arcangeli ret = 1; 45771e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 45871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 45971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46071e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 46171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46271e3aac0SAndrea Arcangeli ret = 1; 46371e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 46471e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 46571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46671e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 46771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 46871e3aac0SAndrea Arcangeli ret = 1; 46971e3aac0SAndrea Arcangeli } 47071e3aac0SAndrea Arcangeli out: 47171e3aac0SAndrea Arcangeli if (!ret) 472ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 47371e3aac0SAndrea Arcangeli return ret; 47471e3aac0SAndrea Arcangeli } 47571e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 47671e3aac0SAndrea Arcangeli 477f55e1014SLinus Torvalds pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 47871e3aac0SAndrea Arcangeli { 479f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 48071e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 48171e3aac0SAndrea Arcangeli return pmd; 48271e3aac0SAndrea Arcangeli } 48371e3aac0SAndrea Arcangeli 48487eaceb3SYang Shi #ifdef CONFIG_MEMCG 48587eaceb3SYang Shi static inline struct deferred_split *get_deferred_split_queue(struct page *page) 4869a982250SKirill A. Shutemov { 48787eaceb3SYang Shi struct mem_cgroup *memcg = compound_head(page)->mem_cgroup; 48887eaceb3SYang Shi struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); 48987eaceb3SYang Shi 49087eaceb3SYang Shi if (memcg) 49187eaceb3SYang Shi return &memcg->deferred_split_queue; 49287eaceb3SYang Shi else 49387eaceb3SYang Shi return &pgdat->deferred_split_queue; 4949a982250SKirill A. Shutemov } 49587eaceb3SYang Shi #else 49687eaceb3SYang Shi static inline struct deferred_split *get_deferred_split_queue(struct page *page) 49787eaceb3SYang Shi { 49887eaceb3SYang Shi struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); 49987eaceb3SYang Shi 50087eaceb3SYang Shi return &pgdat->deferred_split_queue; 50187eaceb3SYang Shi } 50287eaceb3SYang Shi #endif 5039a982250SKirill A. Shutemov 5049a982250SKirill A. Shutemov void prep_transhuge_page(struct page *page) 5059a982250SKirill A. Shutemov { 5069a982250SKirill A. Shutemov /* 5079a982250SKirill A. Shutemov * we use page->mapping and page->indexlru in second tail page 5089a982250SKirill A. Shutemov * as list_head: assuming THP order >= 2 5099a982250SKirill A. Shutemov */ 5109a982250SKirill A. Shutemov 5119a982250SKirill A. Shutemov INIT_LIST_HEAD(page_deferred_list(page)); 5129a982250SKirill A. Shutemov set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); 5139a982250SKirill A. Shutemov } 5149a982250SKirill A. Shutemov 515005ba37cSSean Christopherson bool is_transparent_hugepage(struct page *page) 516005ba37cSSean Christopherson { 517005ba37cSSean Christopherson if (!PageCompound(page)) 518fa1f68ccSZou Wei return false; 519005ba37cSSean Christopherson 520005ba37cSSean Christopherson page = compound_head(page); 521005ba37cSSean Christopherson return is_huge_zero_page(page) || 522005ba37cSSean Christopherson page[1].compound_dtor == TRANSHUGE_PAGE_DTOR; 523005ba37cSSean Christopherson } 524005ba37cSSean Christopherson EXPORT_SYMBOL_GPL(is_transparent_hugepage); 525005ba37cSSean Christopherson 52697d3d0f9SKirill A. Shutemov static unsigned long __thp_get_unmapped_area(struct file *filp, 52797d3d0f9SKirill A. Shutemov unsigned long addr, unsigned long len, 52874d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 52974d2fad1SToshi Kani { 53074d2fad1SToshi Kani loff_t off_end = off + len; 53174d2fad1SToshi Kani loff_t off_align = round_up(off, size); 53297d3d0f9SKirill A. Shutemov unsigned long len_pad, ret; 53374d2fad1SToshi Kani 53474d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 53574d2fad1SToshi Kani return 0; 53674d2fad1SToshi Kani 53774d2fad1SToshi Kani len_pad = len + size; 53874d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 53974d2fad1SToshi Kani return 0; 54074d2fad1SToshi Kani 54197d3d0f9SKirill A. Shutemov ret = current->mm->get_unmapped_area(filp, addr, len_pad, 54274d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 54397d3d0f9SKirill A. Shutemov 54497d3d0f9SKirill A. Shutemov /* 54597d3d0f9SKirill A. Shutemov * The failure might be due to length padding. The caller will retry 54697d3d0f9SKirill A. Shutemov * without the padding. 54797d3d0f9SKirill A. Shutemov */ 54897d3d0f9SKirill A. Shutemov if (IS_ERR_VALUE(ret)) 54974d2fad1SToshi Kani return 0; 55074d2fad1SToshi Kani 55197d3d0f9SKirill A. Shutemov /* 55297d3d0f9SKirill A. Shutemov * Do not try to align to THP boundary if allocation at the address 55397d3d0f9SKirill A. Shutemov * hint succeeds. 55497d3d0f9SKirill A. Shutemov */ 55597d3d0f9SKirill A. Shutemov if (ret == addr) 55674d2fad1SToshi Kani return addr; 55797d3d0f9SKirill A. Shutemov 55897d3d0f9SKirill A. Shutemov ret += (off - ret) & (size - 1); 55997d3d0f9SKirill A. Shutemov return ret; 56074d2fad1SToshi Kani } 56174d2fad1SToshi Kani 56274d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 56374d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 56474d2fad1SToshi Kani { 56597d3d0f9SKirill A. Shutemov unsigned long ret; 56674d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 56774d2fad1SToshi Kani 56874d2fad1SToshi Kani if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) 56974d2fad1SToshi Kani goto out; 57074d2fad1SToshi Kani 57197d3d0f9SKirill A. Shutemov ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); 57297d3d0f9SKirill A. Shutemov if (ret) 57397d3d0f9SKirill A. Shutemov return ret; 57474d2fad1SToshi Kani out: 57574d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 57674d2fad1SToshi Kani } 57774d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 57874d2fad1SToshi Kani 5792b740303SSouptick Joarder static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, 5802b740303SSouptick Joarder struct page *page, gfp_t gfp) 58171e3aac0SAndrea Arcangeli { 58282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 58371e3aac0SAndrea Arcangeli pgtable_t pgtable; 58482b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 5852b740303SSouptick Joarder vm_fault_t ret = 0; 58671e3aac0SAndrea Arcangeli 587309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 58800501b53SJohannes Weiner 589d9eb1ea2SJohannes Weiner if (mem_cgroup_charge(page, vma->vm_mm, gfp)) { 5906b251fc9SAndrea Arcangeli put_page(page); 5916b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 59285b9f46eSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK_CHARGE); 5936b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 5946b251fc9SAndrea Arcangeli } 5959d82c694SJohannes Weiner cgroup_throttle_swaprate(page, gfp); 59671e3aac0SAndrea Arcangeli 5974cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 59800501b53SJohannes Weiner if (unlikely(!pgtable)) { 5996b31d595SMichal Hocko ret = VM_FAULT_OOM; 6006b31d595SMichal Hocko goto release; 60100501b53SJohannes Weiner } 60200501b53SJohannes Weiner 603c79b57e4SHuang Ying clear_huge_page(page, vmf->address, HPAGE_PMD_NR); 60452f37629SMinchan Kim /* 60552f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 60652f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 60752f37629SMinchan Kim * write. 60852f37629SMinchan Kim */ 60971e3aac0SAndrea Arcangeli __SetPageUptodate(page); 61071e3aac0SAndrea Arcangeli 61182b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 61282b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 6136b31d595SMichal Hocko goto unlock_release; 61471e3aac0SAndrea Arcangeli } else { 61571e3aac0SAndrea Arcangeli pmd_t entry; 6166b251fc9SAndrea Arcangeli 6176b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 6186b31d595SMichal Hocko if (ret) 6196b31d595SMichal Hocko goto unlock_release; 6206b31d595SMichal Hocko 6216b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 6226b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 6232b740303SSouptick Joarder vm_fault_t ret2; 6246b251fc9SAndrea Arcangeli 62582b0f8c3SJan Kara spin_unlock(vmf->ptl); 6266b251fc9SAndrea Arcangeli put_page(page); 627bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 6282b740303SSouptick Joarder ret2 = handle_userfault(vmf, VM_UFFD_MISSING); 6292b740303SSouptick Joarder VM_BUG_ON(ret2 & VM_FAULT_FALLBACK); 6302b740303SSouptick Joarder return ret2; 6316b251fc9SAndrea Arcangeli } 6326b251fc9SAndrea Arcangeli 6333122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 634f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 635d281ee61SKirill A. Shutemov page_add_new_anon_rmap(page, vma, haddr, true); 636b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 63782b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 63882b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 639bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 640c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 64182b0f8c3SJan Kara spin_unlock(vmf->ptl); 6426b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 6439d82c694SJohannes Weiner count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); 64471e3aac0SAndrea Arcangeli } 64571e3aac0SAndrea Arcangeli 646aa2e878eSDavid Rientjes return 0; 6476b31d595SMichal Hocko unlock_release: 6486b31d595SMichal Hocko spin_unlock(vmf->ptl); 6496b31d595SMichal Hocko release: 6506b31d595SMichal Hocko if (pgtable) 6516b31d595SMichal Hocko pte_free(vma->vm_mm, pgtable); 6526b31d595SMichal Hocko put_page(page); 6536b31d595SMichal Hocko return ret; 6546b31d595SMichal Hocko 65571e3aac0SAndrea Arcangeli } 65671e3aac0SAndrea Arcangeli 657444eb2a4SMel Gorman /* 65821440d7eSDavid Rientjes * always: directly stall for all thp allocations 65921440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 66021440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 66121440d7eSDavid Rientjes * fail if not immediately available 66221440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 66321440d7eSDavid Rientjes * available 66421440d7eSDavid Rientjes * never: never stall for any thp allocation 665444eb2a4SMel Gorman */ 66619deb769SDavid Rientjes static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) 6670bbbc0b3SAndrea Arcangeli { 66821440d7eSDavid Rientjes const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); 66989c83fb5SMichal Hocko 670ac79f78dSDavid Rientjes /* Always do synchronous compaction */ 67121440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 672a8282608SAndrea Arcangeli return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 673ac79f78dSDavid Rientjes 674ac79f78dSDavid Rientjes /* Kick kcompactd and fail quickly */ 67521440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 67619deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 677ac79f78dSDavid Rientjes 678ac79f78dSDavid Rientjes /* Synchronous compaction if madvised, otherwise kick kcompactd */ 67921440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 68019deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 68119deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 682ac79f78dSDavid Rientjes __GFP_KSWAPD_RECLAIM); 683ac79f78dSDavid Rientjes 684ac79f78dSDavid Rientjes /* Only do synchronous compaction if madvised */ 68521440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 68619deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 68719deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); 688ac79f78dSDavid Rientjes 68919deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT; 690444eb2a4SMel Gorman } 691444eb2a4SMel Gorman 692c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 693d295e341SKirill A. Shutemov static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 69497ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 6955918d10aSKirill A. Shutemov struct page *zero_page) 696fc9fe822SKirill A. Shutemov { 697fc9fe822SKirill A. Shutemov pmd_t entry; 6987c414164SAndrew Morton if (!pmd_none(*pmd)) 6997c414164SAndrew Morton return false; 7005918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 701fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 70212c9d70bSMatthew Wilcox if (pgtable) 7036b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 704fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 705c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 7067c414164SAndrew Morton return true; 707fc9fe822SKirill A. Shutemov } 708fc9fe822SKirill A. Shutemov 7092b740303SSouptick Joarder vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) 71071e3aac0SAndrea Arcangeli { 71182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 712077fcf11SAneesh Kumar K.V gfp_t gfp; 71371e3aac0SAndrea Arcangeli struct page *page; 71482b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 71571e3aac0SAndrea Arcangeli 71643675e6fSYang Shi if (!transhuge_vma_suitable(vma, haddr)) 717c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 71871e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 71971e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 7206d50e60cSDavid Rientjes if (unlikely(khugepaged_enter(vma, vma->vm_flags))) 721ba76149fSAndrea Arcangeli return VM_FAULT_OOM; 72282b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 723bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 72479da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 72580371957SKirill A. Shutemov pgtable_t pgtable; 7265918d10aSKirill A. Shutemov struct page *zero_page; 7272b740303SSouptick Joarder vm_fault_t ret; 7284cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 72980371957SKirill A. Shutemov if (unlikely(!pgtable)) 73080371957SKirill A. Shutemov return VM_FAULT_OOM; 7316fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 7325918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 733bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 73497ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 735c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 73697ae1749SKirill A. Shutemov } 73782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 7386b251fc9SAndrea Arcangeli ret = 0; 73982b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 7406b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 7416b31d595SMichal Hocko if (ret) { 7426b31d595SMichal Hocko spin_unlock(vmf->ptl); 743bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 7446b31d595SMichal Hocko } else if (userfaultfd_missing(vma)) { 74582b0f8c3SJan Kara spin_unlock(vmf->ptl); 746bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 74782b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 7486b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 7496b251fc9SAndrea Arcangeli } else { 750bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 75182b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 75282b0f8c3SJan Kara spin_unlock(vmf->ptl); 7536b251fc9SAndrea Arcangeli } 754bfe8cc1dSGerald Schaefer } else { 75582b0f8c3SJan Kara spin_unlock(vmf->ptl); 756bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 757bfe8cc1dSGerald Schaefer } 7586b251fc9SAndrea Arcangeli return ret; 75980371957SKirill A. Shutemov } 76019deb769SDavid Rientjes gfp = alloc_hugepage_direct_gfpmask(vma); 76119deb769SDavid Rientjes page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); 76281ab4201SAndi Kleen if (unlikely(!page)) { 76381ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 764c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 76581ab4201SAndi Kleen } 7669a982250SKirill A. Shutemov prep_transhuge_page(page); 76782b0f8c3SJan Kara return __do_huge_pmd_anonymous_page(vmf, page, gfp); 76871e3aac0SAndrea Arcangeli } 76971e3aac0SAndrea Arcangeli 770ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 7713b6521f5SOliver O'Halloran pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, 7723b6521f5SOliver O'Halloran pgtable_t pgtable) 7735cad465dSMatthew Wilcox { 7745cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 7755cad465dSMatthew Wilcox pmd_t entry; 7765cad465dSMatthew Wilcox spinlock_t *ptl; 7775cad465dSMatthew Wilcox 7785cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 779c6f3c5eeSAneesh Kumar K.V if (!pmd_none(*pmd)) { 780c6f3c5eeSAneesh Kumar K.V if (write) { 781c6f3c5eeSAneesh Kumar K.V if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { 782c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); 783c6f3c5eeSAneesh Kumar K.V goto out_unlock; 784c6f3c5eeSAneesh Kumar K.V } 785c6f3c5eeSAneesh Kumar K.V entry = pmd_mkyoung(*pmd); 786c6f3c5eeSAneesh Kumar K.V entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 787c6f3c5eeSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) 788c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 789c6f3c5eeSAneesh Kumar K.V } 790c6f3c5eeSAneesh Kumar K.V 791c6f3c5eeSAneesh Kumar K.V goto out_unlock; 792c6f3c5eeSAneesh Kumar K.V } 793c6f3c5eeSAneesh Kumar K.V 794f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 795f25748e3SDan Williams if (pfn_t_devmap(pfn)) 796f25748e3SDan Williams entry = pmd_mkdevmap(entry); 7975cad465dSMatthew Wilcox if (write) { 798f55e1014SLinus Torvalds entry = pmd_mkyoung(pmd_mkdirty(entry)); 799f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(entry, vma); 8005cad465dSMatthew Wilcox } 8013b6521f5SOliver O'Halloran 8023b6521f5SOliver O'Halloran if (pgtable) { 8033b6521f5SOliver O'Halloran pgtable_trans_huge_deposit(mm, pmd, pgtable); 804c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 805c6f3c5eeSAneesh Kumar K.V pgtable = NULL; 8063b6521f5SOliver O'Halloran } 8073b6521f5SOliver O'Halloran 8085cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 8095cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 810c6f3c5eeSAneesh Kumar K.V 811c6f3c5eeSAneesh Kumar K.V out_unlock: 8125cad465dSMatthew Wilcox spin_unlock(ptl); 813c6f3c5eeSAneesh Kumar K.V if (pgtable) 814c6f3c5eeSAneesh Kumar K.V pte_free(mm, pgtable); 8155cad465dSMatthew Wilcox } 8165cad465dSMatthew Wilcox 8179a9731b1SThomas Hellstrom (VMware) /** 8189a9731b1SThomas Hellstrom (VMware) * vmf_insert_pfn_pmd_prot - insert a pmd size pfn 8199a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 8209a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 8219a9731b1SThomas Hellstrom (VMware) * @pgprot: page protection to use 8229a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 8239a9731b1SThomas Hellstrom (VMware) * 8249a9731b1SThomas Hellstrom (VMware) * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and 8259a9731b1SThomas Hellstrom (VMware) * also consult the vmf_insert_mixed_prot() documentation when 8269a9731b1SThomas Hellstrom (VMware) * @pgprot != @vmf->vma->vm_page_prot. 8279a9731b1SThomas Hellstrom (VMware) * 8289a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 8299a9731b1SThomas Hellstrom (VMware) */ 8309a9731b1SThomas Hellstrom (VMware) vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn, 8319a9731b1SThomas Hellstrom (VMware) pgprot_t pgprot, bool write) 8325cad465dSMatthew Wilcox { 833fce86ff5SDan Williams unsigned long addr = vmf->address & PMD_MASK; 834fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 8353b6521f5SOliver O'Halloran pgtable_t pgtable = NULL; 836fce86ff5SDan Williams 8375cad465dSMatthew Wilcox /* 8385cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 8395cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 8405cad465dSMatthew Wilcox * can't support a 'special' bit. 8415cad465dSMatthew Wilcox */ 842e1fb4a08SDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 843e1fb4a08SDave Jiang !pfn_t_devmap(pfn)); 8445cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 8455cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 8465cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 8475cad465dSMatthew Wilcox 8485cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 8495cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 850308a047cSBorislav Petkov 8513b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) { 8524cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 8533b6521f5SOliver O'Halloran if (!pgtable) 8543b6521f5SOliver O'Halloran return VM_FAULT_OOM; 8553b6521f5SOliver O'Halloran } 8563b6521f5SOliver O'Halloran 857308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 858308a047cSBorislav Petkov 859fce86ff5SDan Williams insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); 860ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 8615cad465dSMatthew Wilcox } 8629a9731b1SThomas Hellstrom (VMware) EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot); 8635cad465dSMatthew Wilcox 864a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 865f55e1014SLinus Torvalds static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 866a00cc7d9SMatthew Wilcox { 867f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 868a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 869a00cc7d9SMatthew Wilcox return pud; 870a00cc7d9SMatthew Wilcox } 871a00cc7d9SMatthew Wilcox 872a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 873a00cc7d9SMatthew Wilcox pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) 874a00cc7d9SMatthew Wilcox { 875a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 876a00cc7d9SMatthew Wilcox pud_t entry; 877a00cc7d9SMatthew Wilcox spinlock_t *ptl; 878a00cc7d9SMatthew Wilcox 879a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 880c6f3c5eeSAneesh Kumar K.V if (!pud_none(*pud)) { 881c6f3c5eeSAneesh Kumar K.V if (write) { 882c6f3c5eeSAneesh Kumar K.V if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { 883c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pud(*pud)); 884c6f3c5eeSAneesh Kumar K.V goto out_unlock; 885c6f3c5eeSAneesh Kumar K.V } 886c6f3c5eeSAneesh Kumar K.V entry = pud_mkyoung(*pud); 887c6f3c5eeSAneesh Kumar K.V entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); 888c6f3c5eeSAneesh Kumar K.V if (pudp_set_access_flags(vma, addr, pud, entry, 1)) 889c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pud(vma, addr, pud); 890c6f3c5eeSAneesh Kumar K.V } 891c6f3c5eeSAneesh Kumar K.V goto out_unlock; 892c6f3c5eeSAneesh Kumar K.V } 893c6f3c5eeSAneesh Kumar K.V 894a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 895a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 896a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 897a00cc7d9SMatthew Wilcox if (write) { 898f55e1014SLinus Torvalds entry = pud_mkyoung(pud_mkdirty(entry)); 899f55e1014SLinus Torvalds entry = maybe_pud_mkwrite(entry, vma); 900a00cc7d9SMatthew Wilcox } 901a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 902a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 903c6f3c5eeSAneesh Kumar K.V 904c6f3c5eeSAneesh Kumar K.V out_unlock: 905a00cc7d9SMatthew Wilcox spin_unlock(ptl); 906a00cc7d9SMatthew Wilcox } 907a00cc7d9SMatthew Wilcox 9089a9731b1SThomas Hellstrom (VMware) /** 9099a9731b1SThomas Hellstrom (VMware) * vmf_insert_pfn_pud_prot - insert a pud size pfn 9109a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 9119a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 9129a9731b1SThomas Hellstrom (VMware) * @pgprot: page protection to use 9139a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 9149a9731b1SThomas Hellstrom (VMware) * 9159a9731b1SThomas Hellstrom (VMware) * Insert a pud size pfn. See vmf_insert_pfn() for additional info and 9169a9731b1SThomas Hellstrom (VMware) * also consult the vmf_insert_mixed_prot() documentation when 9179a9731b1SThomas Hellstrom (VMware) * @pgprot != @vmf->vma->vm_page_prot. 9189a9731b1SThomas Hellstrom (VMware) * 9199a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 9209a9731b1SThomas Hellstrom (VMware) */ 9219a9731b1SThomas Hellstrom (VMware) vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, 9229a9731b1SThomas Hellstrom (VMware) pgprot_t pgprot, bool write) 923a00cc7d9SMatthew Wilcox { 924fce86ff5SDan Williams unsigned long addr = vmf->address & PUD_MASK; 925fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 926fce86ff5SDan Williams 927a00cc7d9SMatthew Wilcox /* 928a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 929a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 930a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 931a00cc7d9SMatthew Wilcox */ 93262ec0d8cSDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 93362ec0d8cSDave Jiang !pfn_t_devmap(pfn)); 934a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 935a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 936a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 937a00cc7d9SMatthew Wilcox 938a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 939a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 940a00cc7d9SMatthew Wilcox 941a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 942a00cc7d9SMatthew Wilcox 943fce86ff5SDan Williams insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); 944a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 945a00cc7d9SMatthew Wilcox } 9469a9731b1SThomas Hellstrom (VMware) EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot); 947a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 948a00cc7d9SMatthew Wilcox 9493565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 950a8f97366SKirill A. Shutemov pmd_t *pmd, int flags) 9513565fce3SDan Williams { 9523565fce3SDan Williams pmd_t _pmd; 9533565fce3SDan Williams 954a8f97366SKirill A. Shutemov _pmd = pmd_mkyoung(*pmd); 955a8f97366SKirill A. Shutemov if (flags & FOLL_WRITE) 956a8f97366SKirill A. Shutemov _pmd = pmd_mkdirty(_pmd); 9573565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 958a8f97366SKirill A. Shutemov pmd, _pmd, flags & FOLL_WRITE)) 9593565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 9603565fce3SDan Williams } 9613565fce3SDan Williams 9623565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 963df06b37fSKeith Busch pmd_t *pmd, int flags, struct dev_pagemap **pgmap) 9643565fce3SDan Williams { 9653565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 9663565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 9673565fce3SDan Williams struct page *page; 9683565fce3SDan Williams 9693565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 9703565fce3SDan Williams 9718310d48bSKeno Fischer /* 9728310d48bSKeno Fischer * When we COW a devmap PMD entry, we split it into PTEs, so we should 9738310d48bSKeno Fischer * not be in this function with `flags & FOLL_COW` set. 9748310d48bSKeno Fischer */ 9758310d48bSKeno Fischer WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); 9768310d48bSKeno Fischer 9773faa52c0SJohn Hubbard /* FOLL_GET and FOLL_PIN are mutually exclusive. */ 9783faa52c0SJohn Hubbard if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == 9793faa52c0SJohn Hubbard (FOLL_PIN | FOLL_GET))) 9803faa52c0SJohn Hubbard return NULL; 9813faa52c0SJohn Hubbard 982f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pmd_write(*pmd)) 9833565fce3SDan Williams return NULL; 9843565fce3SDan Williams 9853565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 9863565fce3SDan Williams /* pass */; 9873565fce3SDan Williams else 9883565fce3SDan Williams return NULL; 9893565fce3SDan Williams 9903565fce3SDan Williams if (flags & FOLL_TOUCH) 991a8f97366SKirill A. Shutemov touch_pmd(vma, addr, pmd, flags); 9923565fce3SDan Williams 9933565fce3SDan Williams /* 9943565fce3SDan Williams * device mapped pages can only be returned if the 9953565fce3SDan Williams * caller will manage the page reference count. 9963565fce3SDan Williams */ 9973faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 9983565fce3SDan Williams return ERR_PTR(-EEXIST); 9993565fce3SDan Williams 10003565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 1001df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1002df06b37fSKeith Busch if (!*pgmap) 10033565fce3SDan Williams return ERR_PTR(-EFAULT); 10043565fce3SDan Williams page = pfn_to_page(pfn); 10053faa52c0SJohn Hubbard if (!try_grab_page(page, flags)) 10063faa52c0SJohn Hubbard page = ERR_PTR(-ENOMEM); 10073565fce3SDan Williams 10083565fce3SDan Williams return page; 10093565fce3SDan Williams } 10103565fce3SDan Williams 101171e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 101271e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 101371e3aac0SAndrea Arcangeli struct vm_area_struct *vma) 101471e3aac0SAndrea Arcangeli { 1015c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 101671e3aac0SAndrea Arcangeli struct page *src_page; 101771e3aac0SAndrea Arcangeli pmd_t pmd; 101812c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 1019628d47ceSKirill A. Shutemov int ret = -ENOMEM; 102071e3aac0SAndrea Arcangeli 1021628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 1022628d47ceSKirill A. Shutemov if (!vma_is_anonymous(vma)) 1023628d47ceSKirill A. Shutemov return 0; 1024628d47ceSKirill A. Shutemov 10254cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(dst_mm); 102671e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 102771e3aac0SAndrea Arcangeli goto out; 102871e3aac0SAndrea Arcangeli 1029c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 1030c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 1031c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 103271e3aac0SAndrea Arcangeli 103371e3aac0SAndrea Arcangeli ret = -EAGAIN; 103471e3aac0SAndrea Arcangeli pmd = *src_pmd; 103584c3fc4eSZi Yan 1036b569a176SPeter Xu /* 1037b569a176SPeter Xu * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA 1038b569a176SPeter Xu * does not have the VM_UFFD_WP, which means that the uffd 1039b569a176SPeter Xu * fork event is not enabled. 1040b569a176SPeter Xu */ 1041b569a176SPeter Xu if (!(vma->vm_flags & VM_UFFD_WP)) 1042b569a176SPeter Xu pmd = pmd_clear_uffd_wp(pmd); 1043b569a176SPeter Xu 104484c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 104584c3fc4eSZi Yan if (unlikely(is_swap_pmd(pmd))) { 104684c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(pmd); 104784c3fc4eSZi Yan 104884c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(pmd)); 104984c3fc4eSZi Yan if (is_write_migration_entry(entry)) { 105084c3fc4eSZi Yan make_migration_entry_read(&entry); 105184c3fc4eSZi Yan pmd = swp_entry_to_pmd(entry); 1052ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*src_pmd)) 1053ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 105484c3fc4eSZi Yan set_pmd_at(src_mm, addr, src_pmd, pmd); 105584c3fc4eSZi Yan } 1056dd8a67f9SZi Yan add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1057af5b0f6aSKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 1058dd8a67f9SZi Yan pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 105984c3fc4eSZi Yan set_pmd_at(dst_mm, addr, dst_pmd, pmd); 106084c3fc4eSZi Yan ret = 0; 106184c3fc4eSZi Yan goto out_unlock; 106284c3fc4eSZi Yan } 106384c3fc4eSZi Yan #endif 106484c3fc4eSZi Yan 1065628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 106671e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 106771e3aac0SAndrea Arcangeli goto out_unlock; 106871e3aac0SAndrea Arcangeli } 1069fc9fe822SKirill A. Shutemov /* 1070c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 1071fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 1072fc9fe822SKirill A. Shutemov * a page table. 1073fc9fe822SKirill A. Shutemov */ 1074fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 10755918d10aSKirill A. Shutemov struct page *zero_page; 107697ae1749SKirill A. Shutemov /* 107797ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 107897ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 107997ae1749SKirill A. Shutemov * reference. 108097ae1749SKirill A. Shutemov */ 10816fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(dst_mm); 10826b251fc9SAndrea Arcangeli set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, 10835918d10aSKirill A. Shutemov zero_page); 1084fc9fe822SKirill A. Shutemov ret = 0; 1085fc9fe822SKirill A. Shutemov goto out_unlock; 1086fc9fe822SKirill A. Shutemov } 1087de466bd6SMel Gorman 108871e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 1089309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 1090d042035eSPeter Xu 1091d042035eSPeter Xu /* 1092d042035eSPeter Xu * If this page is a potentially pinned page, split and retry the fault 1093d042035eSPeter Xu * with smaller page size. Normally this should not happen because the 1094d042035eSPeter Xu * userspace should use MADV_DONTFORK upon pinned regions. This is a 1095d042035eSPeter Xu * best effort that the pinned pages won't be replaced by another 1096d042035eSPeter Xu * random page during the coming copy-on-write. 1097d042035eSPeter Xu */ 1098d042035eSPeter Xu if (unlikely(is_cow_mapping(vma->vm_flags) && 1099d042035eSPeter Xu atomic_read(&src_mm->has_pinned) && 1100d042035eSPeter Xu page_maybe_dma_pinned(src_page))) { 1101d042035eSPeter Xu pte_free(dst_mm, pgtable); 1102d042035eSPeter Xu spin_unlock(src_ptl); 1103d042035eSPeter Xu spin_unlock(dst_ptl); 1104d042035eSPeter Xu __split_huge_pmd(vma, src_pmd, addr, false, NULL); 1105d042035eSPeter Xu return -EAGAIN; 1106d042035eSPeter Xu } 1107d042035eSPeter Xu 110871e3aac0SAndrea Arcangeli get_page(src_page); 110953f9263bSKirill A. Shutemov page_dup_rmap(src_page, true); 111071e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1111c4812909SKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 11125c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 111371e3aac0SAndrea Arcangeli 111471e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 111571e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 111671e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 111771e3aac0SAndrea Arcangeli 111871e3aac0SAndrea Arcangeli ret = 0; 111971e3aac0SAndrea Arcangeli out_unlock: 1120c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 1121c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 112271e3aac0SAndrea Arcangeli out: 112371e3aac0SAndrea Arcangeli return ret; 112471e3aac0SAndrea Arcangeli } 112571e3aac0SAndrea Arcangeli 1126a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1127a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 1128a8f97366SKirill A. Shutemov pud_t *pud, int flags) 1129a00cc7d9SMatthew Wilcox { 1130a00cc7d9SMatthew Wilcox pud_t _pud; 1131a00cc7d9SMatthew Wilcox 1132a8f97366SKirill A. Shutemov _pud = pud_mkyoung(*pud); 1133a8f97366SKirill A. Shutemov if (flags & FOLL_WRITE) 1134a8f97366SKirill A. Shutemov _pud = pud_mkdirty(_pud); 1135a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 1136a8f97366SKirill A. Shutemov pud, _pud, flags & FOLL_WRITE)) 1137a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1138a00cc7d9SMatthew Wilcox } 1139a00cc7d9SMatthew Wilcox 1140a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 1141df06b37fSKeith Busch pud_t *pud, int flags, struct dev_pagemap **pgmap) 1142a00cc7d9SMatthew Wilcox { 1143a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 1144a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1145a00cc7d9SMatthew Wilcox struct page *page; 1146a00cc7d9SMatthew Wilcox 1147a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 1148a00cc7d9SMatthew Wilcox 1149f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pud_write(*pud)) 1150a00cc7d9SMatthew Wilcox return NULL; 1151a00cc7d9SMatthew Wilcox 11523faa52c0SJohn Hubbard /* FOLL_GET and FOLL_PIN are mutually exclusive. */ 11533faa52c0SJohn Hubbard if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == 11543faa52c0SJohn Hubbard (FOLL_PIN | FOLL_GET))) 11553faa52c0SJohn Hubbard return NULL; 11563faa52c0SJohn Hubbard 1157a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 1158a00cc7d9SMatthew Wilcox /* pass */; 1159a00cc7d9SMatthew Wilcox else 1160a00cc7d9SMatthew Wilcox return NULL; 1161a00cc7d9SMatthew Wilcox 1162a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 1163a8f97366SKirill A. Shutemov touch_pud(vma, addr, pud, flags); 1164a00cc7d9SMatthew Wilcox 1165a00cc7d9SMatthew Wilcox /* 1166a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 1167a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 11683faa52c0SJohn Hubbard * 11693faa52c0SJohn Hubbard * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: 1170a00cc7d9SMatthew Wilcox */ 11713faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 1172a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 1173a00cc7d9SMatthew Wilcox 1174a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 1175df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1176df06b37fSKeith Busch if (!*pgmap) 1177a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 1178a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 11793faa52c0SJohn Hubbard if (!try_grab_page(page, flags)) 11803faa52c0SJohn Hubbard page = ERR_PTR(-ENOMEM); 1181a00cc7d9SMatthew Wilcox 1182a00cc7d9SMatthew Wilcox return page; 1183a00cc7d9SMatthew Wilcox } 1184a00cc7d9SMatthew Wilcox 1185a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1186a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1187a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1188a00cc7d9SMatthew Wilcox { 1189a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1190a00cc7d9SMatthew Wilcox pud_t pud; 1191a00cc7d9SMatthew Wilcox int ret; 1192a00cc7d9SMatthew Wilcox 1193a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1194a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1195a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1196a00cc7d9SMatthew Wilcox 1197a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1198a00cc7d9SMatthew Wilcox pud = *src_pud; 1199a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1200a00cc7d9SMatthew Wilcox goto out_unlock; 1201a00cc7d9SMatthew Wilcox 1202a00cc7d9SMatthew Wilcox /* 1203a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1204a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1205a00cc7d9SMatthew Wilcox * a page table. 1206a00cc7d9SMatthew Wilcox */ 1207a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1208a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1209a00cc7d9SMatthew Wilcox } 1210a00cc7d9SMatthew Wilcox 1211d042035eSPeter Xu /* Please refer to comments in copy_huge_pmd() */ 1212d042035eSPeter Xu if (unlikely(is_cow_mapping(vma->vm_flags) && 1213d042035eSPeter Xu atomic_read(&src_mm->has_pinned) && 1214d042035eSPeter Xu page_maybe_dma_pinned(pud_page(pud)))) { 1215d042035eSPeter Xu spin_unlock(src_ptl); 1216d042035eSPeter Xu spin_unlock(dst_ptl); 1217d042035eSPeter Xu __split_huge_pud(vma, src_pud, addr); 1218d042035eSPeter Xu return -EAGAIN; 1219d042035eSPeter Xu } 1220d042035eSPeter Xu 1221a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1222a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1223a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1224a00cc7d9SMatthew Wilcox 1225a00cc7d9SMatthew Wilcox ret = 0; 1226a00cc7d9SMatthew Wilcox out_unlock: 1227a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1228a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1229a00cc7d9SMatthew Wilcox return ret; 1230a00cc7d9SMatthew Wilcox } 1231a00cc7d9SMatthew Wilcox 1232a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1233a00cc7d9SMatthew Wilcox { 1234a00cc7d9SMatthew Wilcox pud_t entry; 1235a00cc7d9SMatthew Wilcox unsigned long haddr; 1236a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1237a00cc7d9SMatthew Wilcox 1238a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1239a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1240a00cc7d9SMatthew Wilcox goto unlock; 1241a00cc7d9SMatthew Wilcox 1242a00cc7d9SMatthew Wilcox entry = pud_mkyoung(orig_pud); 1243a00cc7d9SMatthew Wilcox if (write) 1244a00cc7d9SMatthew Wilcox entry = pud_mkdirty(entry); 1245a00cc7d9SMatthew Wilcox haddr = vmf->address & HPAGE_PUD_MASK; 1246a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) 1247a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); 1248a00cc7d9SMatthew Wilcox 1249a00cc7d9SMatthew Wilcox unlock: 1250a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1251a00cc7d9SMatthew Wilcox } 1252a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1253a00cc7d9SMatthew Wilcox 125482b0f8c3SJan Kara void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) 1255a1dd450bSWill Deacon { 1256a1dd450bSWill Deacon pmd_t entry; 1257a1dd450bSWill Deacon unsigned long haddr; 125820f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1259a1dd450bSWill Deacon 126082b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 126182b0f8c3SJan Kara if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) 1262a1dd450bSWill Deacon goto unlock; 1263a1dd450bSWill Deacon 1264a1dd450bSWill Deacon entry = pmd_mkyoung(orig_pmd); 126520f664aaSMinchan Kim if (write) 126620f664aaSMinchan Kim entry = pmd_mkdirty(entry); 126782b0f8c3SJan Kara haddr = vmf->address & HPAGE_PMD_MASK; 126820f664aaSMinchan Kim if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) 126982b0f8c3SJan Kara update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); 1270a1dd450bSWill Deacon 1271a1dd450bSWill Deacon unlock: 127282b0f8c3SJan Kara spin_unlock(vmf->ptl); 1273a1dd450bSWill Deacon } 1274a1dd450bSWill Deacon 12752b740303SSouptick Joarder vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) 127671e3aac0SAndrea Arcangeli { 127782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 12783917c802SKirill A. Shutemov struct page *page; 127982b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 128071e3aac0SAndrea Arcangeli 128182b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 128281d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 12833917c802SKirill A. Shutemov 128493b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 12853917c802SKirill A. Shutemov goto fallback; 12863917c802SKirill A. Shutemov 128782b0f8c3SJan Kara spin_lock(vmf->ptl); 12883917c802SKirill A. Shutemov 12893917c802SKirill A. Shutemov if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 12903917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 12913917c802SKirill A. Shutemov return 0; 12923917c802SKirill A. Shutemov } 129371e3aac0SAndrea Arcangeli 129471e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 1295309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); 12963917c802SKirill A. Shutemov 12973917c802SKirill A. Shutemov /* Lock page for reuse_swap_page() */ 1298ba3c4ce6SHuang Ying if (!trylock_page(page)) { 1299ba3c4ce6SHuang Ying get_page(page); 1300ba3c4ce6SHuang Ying spin_unlock(vmf->ptl); 1301ba3c4ce6SHuang Ying lock_page(page); 1302ba3c4ce6SHuang Ying spin_lock(vmf->ptl); 1303ba3c4ce6SHuang Ying if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13043917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 1305ba3c4ce6SHuang Ying unlock_page(page); 1306ba3c4ce6SHuang Ying put_page(page); 13073917c802SKirill A. Shutemov return 0; 1308ba3c4ce6SHuang Ying } 1309ba3c4ce6SHuang Ying put_page(page); 1310ba3c4ce6SHuang Ying } 13113917c802SKirill A. Shutemov 13123917c802SKirill A. Shutemov /* 13133917c802SKirill A. Shutemov * We can only reuse the page if nobody else maps the huge page or it's 13143917c802SKirill A. Shutemov * part. 13153917c802SKirill A. Shutemov */ 1316ba3c4ce6SHuang Ying if (reuse_swap_page(page, NULL)) { 131771e3aac0SAndrea Arcangeli pmd_t entry; 131871e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 1319f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 132082b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 132182b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1322ba3c4ce6SHuang Ying unlock_page(page); 13233917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13243917c802SKirill A. Shutemov return VM_FAULT_WRITE; 132571e3aac0SAndrea Arcangeli } 13263917c802SKirill A. Shutemov 1327ba3c4ce6SHuang Ying unlock_page(page); 132882b0f8c3SJan Kara spin_unlock(vmf->ptl); 13293917c802SKirill A. Shutemov fallback: 13303917c802SKirill A. Shutemov __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); 13313917c802SKirill A. Shutemov return VM_FAULT_FALLBACK; 133271e3aac0SAndrea Arcangeli } 133371e3aac0SAndrea Arcangeli 13348310d48bSKeno Fischer /* 1335a308c71bSPeter Xu * FOLL_FORCE can write to even unwritable pmd's, but only 1336a308c71bSPeter Xu * after we've gone through a COW cycle and they are dirty. 13378310d48bSKeno Fischer */ 13388310d48bSKeno Fischer static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) 13398310d48bSKeno Fischer { 1340a308c71bSPeter Xu return pmd_write(pmd) || 1341a308c71bSPeter Xu ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); 13428310d48bSKeno Fischer } 13438310d48bSKeno Fischer 1344b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 134571e3aac0SAndrea Arcangeli unsigned long addr, 134671e3aac0SAndrea Arcangeli pmd_t *pmd, 134771e3aac0SAndrea Arcangeli unsigned int flags) 134871e3aac0SAndrea Arcangeli { 1349b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 135071e3aac0SAndrea Arcangeli struct page *page = NULL; 135171e3aac0SAndrea Arcangeli 1352c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 135371e3aac0SAndrea Arcangeli 13548310d48bSKeno Fischer if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) 135571e3aac0SAndrea Arcangeli goto out; 135671e3aac0SAndrea Arcangeli 135785facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 135885facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 135985facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 136085facf25SKirill A. Shutemov 13612b4847e7SMel Gorman /* Full NUMA hinting faults to serialise migration in fault paths */ 13628a0516edSMel Gorman if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) 13632b4847e7SMel Gorman goto out; 13642b4847e7SMel Gorman 136571e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 1366ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 13673faa52c0SJohn Hubbard 13683faa52c0SJohn Hubbard if (!try_grab_page(page, flags)) 13693faa52c0SJohn Hubbard return ERR_PTR(-ENOMEM); 13703faa52c0SJohn Hubbard 13713565fce3SDan Williams if (flags & FOLL_TOUCH) 1372a8f97366SKirill A. Shutemov touch_pmd(vma, addr, pmd, flags); 13733faa52c0SJohn Hubbard 1374de60f5f1SEric B Munson if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { 1375e90309c9SKirill A. Shutemov /* 1376e90309c9SKirill A. Shutemov * We don't mlock() pte-mapped THPs. This way we can avoid 1377e90309c9SKirill A. Shutemov * leaking mlocked pages into non-VM_LOCKED VMAs. 1378e90309c9SKirill A. Shutemov * 13799a73f61bSKirill A. Shutemov * For anon THP: 13809a73f61bSKirill A. Shutemov * 1381e90309c9SKirill A. Shutemov * In most cases the pmd is the only mapping of the page as we 1382e90309c9SKirill A. Shutemov * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for 1383e90309c9SKirill A. Shutemov * writable private mappings in populate_vma_page_range(). 1384e90309c9SKirill A. Shutemov * 1385e90309c9SKirill A. Shutemov * The only scenario when we have the page shared here is if we 1386e90309c9SKirill A. Shutemov * mlocking read-only mapping shared over fork(). We skip 1387e90309c9SKirill A. Shutemov * mlocking such pages. 13889a73f61bSKirill A. Shutemov * 13899a73f61bSKirill A. Shutemov * For file THP: 13909a73f61bSKirill A. Shutemov * 13919a73f61bSKirill A. Shutemov * We can expect PageDoubleMap() to be stable under page lock: 13929a73f61bSKirill A. Shutemov * for file pages we set it in page_add_file_rmap(), which 13939a73f61bSKirill A. Shutemov * requires page to be locked. 1394e90309c9SKirill A. Shutemov */ 13959a73f61bSKirill A. Shutemov 13969a73f61bSKirill A. Shutemov if (PageAnon(page) && compound_mapcount(page) != 1) 13979a73f61bSKirill A. Shutemov goto skip_mlock; 13989a73f61bSKirill A. Shutemov if (PageDoubleMap(page) || !page->mapping) 13999a73f61bSKirill A. Shutemov goto skip_mlock; 14009a73f61bSKirill A. Shutemov if (!trylock_page(page)) 14019a73f61bSKirill A. Shutemov goto skip_mlock; 14029a73f61bSKirill A. Shutemov if (page->mapping && !PageDoubleMap(page)) 1403b676b293SDavid Rientjes mlock_vma_page(page); 1404b676b293SDavid Rientjes unlock_page(page); 1405b676b293SDavid Rientjes } 14069a73f61bSKirill A. Shutemov skip_mlock: 140771e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1408ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 140971e3aac0SAndrea Arcangeli 141071e3aac0SAndrea Arcangeli out: 141171e3aac0SAndrea Arcangeli return page; 141271e3aac0SAndrea Arcangeli } 141371e3aac0SAndrea Arcangeli 1414d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 14152b740303SSouptick Joarder vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) 1416d10e63f2SMel Gorman { 141782b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1418b8916634SMel Gorman struct anon_vma *anon_vma = NULL; 1419b32967ffSMel Gorman struct page *page; 142082b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 142198fa15f3SAnshuman Khandual int page_nid = NUMA_NO_NODE, this_nid = numa_node_id(); 142290572890SPeter Zijlstra int target_nid, last_cpupid = -1; 14238191acbdSMel Gorman bool page_locked; 14248191acbdSMel Gorman bool migrated = false; 1425b191f9b1SMel Gorman bool was_writable; 14266688cc05SPeter Zijlstra int flags = 0; 1427d10e63f2SMel Gorman 142882b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 142982b0f8c3SJan Kara if (unlikely(!pmd_same(pmd, *vmf->pmd))) 1430d10e63f2SMel Gorman goto out_unlock; 1431d10e63f2SMel Gorman 1432de466bd6SMel Gorman /* 1433de466bd6SMel Gorman * If there are potential migrations, wait for completion and retry 1434de466bd6SMel Gorman * without disrupting NUMA hinting information. Do not relock and 1435de466bd6SMel Gorman * check_same as the page may no longer be mapped. 1436de466bd6SMel Gorman */ 143782b0f8c3SJan Kara if (unlikely(pmd_trans_migrating(*vmf->pmd))) { 143882b0f8c3SJan Kara page = pmd_page(*vmf->pmd); 14393c226c63SMark Rutland if (!get_page_unless_zero(page)) 14403c226c63SMark Rutland goto out_unlock; 144182b0f8c3SJan Kara spin_unlock(vmf->ptl); 14429a1ea439SHugh Dickins put_and_wait_on_page_locked(page); 1443de466bd6SMel Gorman goto out; 1444de466bd6SMel Gorman } 1445de466bd6SMel Gorman 1446d10e63f2SMel Gorman page = pmd_page(pmd); 1447a1a46184SMel Gorman BUG_ON(is_huge_zero_page(page)); 14488191acbdSMel Gorman page_nid = page_to_nid(page); 144990572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 145003c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 145104bb2f94SRik van Riel if (page_nid == this_nid) { 145203c5a6e1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 145304bb2f94SRik van Riel flags |= TNF_FAULT_LOCAL; 145404bb2f94SRik van Riel } 14554daae3b4SMel Gorman 1456bea66fbdSMel Gorman /* See similar comment in do_numa_page for explanation */ 1457288bc549SAneesh Kumar K.V if (!pmd_savedwrite(pmd)) 14586688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 14596688cc05SPeter Zijlstra 14606688cc05SPeter Zijlstra /* 1461ff9042b1SMel Gorman * Acquire the page lock to serialise THP migrations but avoid dropping 1462ff9042b1SMel Gorman * page_table_lock if at all possible 1463ff9042b1SMel Gorman */ 1464b8916634SMel Gorman page_locked = trylock_page(page); 1465b8916634SMel Gorman target_nid = mpol_misplaced(page, vma, haddr); 146698fa15f3SAnshuman Khandual if (target_nid == NUMA_NO_NODE) { 1467b8916634SMel Gorman /* If the page was locked, there are no parallel migrations */ 1468a54a407fSMel Gorman if (page_locked) 1469b8916634SMel Gorman goto clear_pmdnuma; 14702b4847e7SMel Gorman } 1471cbee9f88SPeter Zijlstra 1472de466bd6SMel Gorman /* Migration could have started since the pmd_trans_migrating check */ 14732b4847e7SMel Gorman if (!page_locked) { 147498fa15f3SAnshuman Khandual page_nid = NUMA_NO_NODE; 14753c226c63SMark Rutland if (!get_page_unless_zero(page)) 14763c226c63SMark Rutland goto out_unlock; 147782b0f8c3SJan Kara spin_unlock(vmf->ptl); 14789a1ea439SHugh Dickins put_and_wait_on_page_locked(page); 1479b8916634SMel Gorman goto out; 1480b8916634SMel Gorman } 1481b8916634SMel Gorman 14822b4847e7SMel Gorman /* 14832b4847e7SMel Gorman * Page is misplaced. Page lock serialises migrations. Acquire anon_vma 14842b4847e7SMel Gorman * to serialises splits 14852b4847e7SMel Gorman */ 1486b8916634SMel Gorman get_page(page); 148782b0f8c3SJan Kara spin_unlock(vmf->ptl); 1488b8916634SMel Gorman anon_vma = page_lock_anon_vma_read(page); 1489b32967ffSMel Gorman 1490c69307d5SPeter Zijlstra /* Confirm the PMD did not change while page_table_lock was released */ 149182b0f8c3SJan Kara spin_lock(vmf->ptl); 149282b0f8c3SJan Kara if (unlikely(!pmd_same(pmd, *vmf->pmd))) { 1493b32967ffSMel Gorman unlock_page(page); 1494b32967ffSMel Gorman put_page(page); 149598fa15f3SAnshuman Khandual page_nid = NUMA_NO_NODE; 1496b32967ffSMel Gorman goto out_unlock; 1497b32967ffSMel Gorman } 1498ff9042b1SMel Gorman 1499c3a489caSMel Gorman /* Bail if we fail to protect against THP splits for any reason */ 1500c3a489caSMel Gorman if (unlikely(!anon_vma)) { 1501c3a489caSMel Gorman put_page(page); 150298fa15f3SAnshuman Khandual page_nid = NUMA_NO_NODE; 1503c3a489caSMel Gorman goto clear_pmdnuma; 1504c3a489caSMel Gorman } 1505c3a489caSMel Gorman 1506a54a407fSMel Gorman /* 15078b1b436dSPeter Zijlstra * Since we took the NUMA fault, we must have observed the !accessible 15088b1b436dSPeter Zijlstra * bit. Make sure all other CPUs agree with that, to avoid them 15098b1b436dSPeter Zijlstra * modifying the page we're about to migrate. 15108b1b436dSPeter Zijlstra * 15118b1b436dSPeter Zijlstra * Must be done under PTL such that we'll observe the relevant 1512ccde85baSPeter Zijlstra * inc_tlb_flush_pending(). 1513ccde85baSPeter Zijlstra * 1514ccde85baSPeter Zijlstra * We are not sure a pending tlb flush here is for a huge page 1515ccde85baSPeter Zijlstra * mapping or not. Hence use the tlb range variant 15168b1b436dSPeter Zijlstra */ 15177066f0f9SAndrea Arcangeli if (mm_tlb_flush_pending(vma->vm_mm)) { 1518ccde85baSPeter Zijlstra flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); 15197066f0f9SAndrea Arcangeli /* 15207066f0f9SAndrea Arcangeli * change_huge_pmd() released the pmd lock before 15217066f0f9SAndrea Arcangeli * invalidating the secondary MMUs sharing the primary 15227066f0f9SAndrea Arcangeli * MMU pagetables (with ->invalidate_range()). The 15237066f0f9SAndrea Arcangeli * mmu_notifier_invalidate_range_end() (which 15247066f0f9SAndrea Arcangeli * internally calls ->invalidate_range()) in 15257066f0f9SAndrea Arcangeli * change_pmd_range() will run after us, so we can't 15267066f0f9SAndrea Arcangeli * rely on it here and we need an explicit invalidate. 15277066f0f9SAndrea Arcangeli */ 15287066f0f9SAndrea Arcangeli mmu_notifier_invalidate_range(vma->vm_mm, haddr, 15297066f0f9SAndrea Arcangeli haddr + HPAGE_PMD_SIZE); 15307066f0f9SAndrea Arcangeli } 15318b1b436dSPeter Zijlstra 15328b1b436dSPeter Zijlstra /* 1533a54a407fSMel Gorman * Migrate the THP to the requested node, returns with page unlocked 15348a0516edSMel Gorman * and access rights restored. 1535a54a407fSMel Gorman */ 153682b0f8c3SJan Kara spin_unlock(vmf->ptl); 15378b1b436dSPeter Zijlstra 1538bae473a4SKirill A. Shutemov migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, 153982b0f8c3SJan Kara vmf->pmd, pmd, vmf->address, page, target_nid); 15406688cc05SPeter Zijlstra if (migrated) { 15416688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 15428191acbdSMel Gorman page_nid = target_nid; 1543074c2381SMel Gorman } else 1544074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1545b32967ffSMel Gorman 15468191acbdSMel Gorman goto out; 15474daae3b4SMel Gorman clear_pmdnuma: 1548a54a407fSMel Gorman BUG_ON(!PageLocked(page)); 1549288bc549SAneesh Kumar K.V was_writable = pmd_savedwrite(pmd); 15504d942466SMel Gorman pmd = pmd_modify(pmd, vma->vm_page_prot); 1551b7b04004SMel Gorman pmd = pmd_mkyoung(pmd); 1552b191f9b1SMel Gorman if (was_writable) 1553b191f9b1SMel Gorman pmd = pmd_mkwrite(pmd); 155482b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 155582b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1556a54a407fSMel Gorman unlock_page(page); 1557d10e63f2SMel Gorman out_unlock: 155882b0f8c3SJan Kara spin_unlock(vmf->ptl); 1559b8916634SMel Gorman 1560b8916634SMel Gorman out: 1561b8916634SMel Gorman if (anon_vma) 1562b8916634SMel Gorman page_unlock_anon_vma_read(anon_vma); 1563b8916634SMel Gorman 156498fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 156582b0f8c3SJan Kara task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, 15669a8b300fSAneesh Kumar K.V flags); 15678191acbdSMel Gorman 1568d10e63f2SMel Gorman return 0; 1569d10e63f2SMel Gorman } 1570d10e63f2SMel Gorman 1571319904adSHuang Ying /* 1572319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1573319904adSHuang Ying * Otherwise, return false. 1574319904adSHuang Ying */ 1575319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1576b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1577b8d3c4c3SMinchan Kim { 1578b8d3c4c3SMinchan Kim spinlock_t *ptl; 1579b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1580b8d3c4c3SMinchan Kim struct page *page; 1581b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1582319904adSHuang Ying bool ret = false; 1583b8d3c4c3SMinchan Kim 1584ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 158507e32661SAneesh Kumar K.V 1586b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1587b6ec57f4SKirill A. Shutemov if (!ptl) 158825eedabeSLinus Torvalds goto out_unlocked; 1589b8d3c4c3SMinchan Kim 1590b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1591319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1592b8d3c4c3SMinchan Kim goto out; 1593b8d3c4c3SMinchan Kim 159484c3fc4eSZi Yan if (unlikely(!pmd_present(orig_pmd))) { 159584c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 159684c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 159784c3fc4eSZi Yan goto out; 159884c3fc4eSZi Yan } 159984c3fc4eSZi Yan 1600b8d3c4c3SMinchan Kim page = pmd_page(orig_pmd); 1601b8d3c4c3SMinchan Kim /* 1602b8d3c4c3SMinchan Kim * If other processes are mapping this page, we couldn't discard 1603b8d3c4c3SMinchan Kim * the page unless they all do MADV_FREE so let's skip the page. 1604b8d3c4c3SMinchan Kim */ 1605b8d3c4c3SMinchan Kim if (page_mapcount(page) != 1) 1606b8d3c4c3SMinchan Kim goto out; 1607b8d3c4c3SMinchan Kim 1608b8d3c4c3SMinchan Kim if (!trylock_page(page)) 1609b8d3c4c3SMinchan Kim goto out; 1610b8d3c4c3SMinchan Kim 1611b8d3c4c3SMinchan Kim /* 1612b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1613b8d3c4c3SMinchan Kim * will deactivate only them. 1614b8d3c4c3SMinchan Kim */ 1615b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1616b8d3c4c3SMinchan Kim get_page(page); 1617b8d3c4c3SMinchan Kim spin_unlock(ptl); 16189818b8cdSHuang Ying split_huge_page(page); 1619b8d3c4c3SMinchan Kim unlock_page(page); 1620bbf29ffcSKirill A. Shutemov put_page(page); 1621b8d3c4c3SMinchan Kim goto out_unlocked; 1622b8d3c4c3SMinchan Kim } 1623b8d3c4c3SMinchan Kim 1624b8d3c4c3SMinchan Kim if (PageDirty(page)) 1625b8d3c4c3SMinchan Kim ClearPageDirty(page); 1626b8d3c4c3SMinchan Kim unlock_page(page); 1627b8d3c4c3SMinchan Kim 1628b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 162958ceeb6bSKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1630b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1631b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1632b8d3c4c3SMinchan Kim 1633b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1634b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1635b8d3c4c3SMinchan Kim } 1636802a3a92SShaohua Li 1637802a3a92SShaohua Li mark_page_lazyfree(page); 1638319904adSHuang Ying ret = true; 1639b8d3c4c3SMinchan Kim out: 1640b8d3c4c3SMinchan Kim spin_unlock(ptl); 1641b8d3c4c3SMinchan Kim out_unlocked: 1642b8d3c4c3SMinchan Kim return ret; 1643b8d3c4c3SMinchan Kim } 1644b8d3c4c3SMinchan Kim 1645953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1646953c66c2SAneesh Kumar K.V { 1647953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1648953c66c2SAneesh Kumar K.V 1649953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1650953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1651c4812909SKirill A. Shutemov mm_dec_nr_ptes(mm); 1652953c66c2SAneesh Kumar K.V } 1653953c66c2SAneesh Kumar K.V 165471e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1655f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 165671e3aac0SAndrea Arcangeli { 1657f5c8ad47SDavid Miller pmd_t orig_pmd; 1658da146769SKirill A. Shutemov spinlock_t *ptl; 1659da146769SKirill A. Shutemov 1660ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 166107e32661SAneesh Kumar K.V 1662b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1663b6ec57f4SKirill A. Shutemov if (!ptl) 1664da146769SKirill A. Shutemov return 0; 1665a6bf2bb0SAneesh Kumar K.V /* 1666a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 16678809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1668a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1669a6bf2bb0SAneesh Kumar K.V * operations. 1670a6bf2bb0SAneesh Kumar K.V */ 167193a98695SAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, 1672fcbe08d6SMartin Schwidefsky tlb->fullmm); 1673f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 16742484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 16753b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) 16763b6521f5SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 16774897c765SMatthew Wilcox spin_unlock(ptl); 1678da146769SKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 1679c0f2e176SAneesh Kumar K.V tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); 1680da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1681c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1682bf929152SKirill A. Shutemov spin_unlock(ptl); 1683c0f2e176SAneesh Kumar K.V tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); 1684479f0abbSKirill A. Shutemov } else { 1685616b8371SZi Yan struct page *page = NULL; 1686616b8371SZi Yan int flush_needed = 1; 1687616b8371SZi Yan 1688616b8371SZi Yan if (pmd_present(orig_pmd)) { 1689616b8371SZi Yan page = pmd_page(orig_pmd); 1690d281ee61SKirill A. Shutemov page_remove_rmap(page, true); 1691309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1692309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1693616b8371SZi Yan } else if (thp_migration_supported()) { 1694616b8371SZi Yan swp_entry_t entry; 1695616b8371SZi Yan 1696616b8371SZi Yan VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); 1697616b8371SZi Yan entry = pmd_to_swp_entry(orig_pmd); 1698616b8371SZi Yan page = pfn_to_page(swp_offset(entry)); 1699616b8371SZi Yan flush_needed = 0; 1700616b8371SZi Yan } else 1701616b8371SZi Yan WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); 1702616b8371SZi Yan 1703b5072380SKirill A. Shutemov if (PageAnon(page)) { 1704c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1705b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1706b5072380SKirill A. Shutemov } else { 1707953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1708953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1709fadae295SYang Shi add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); 1710b5072380SKirill A. Shutemov } 1711616b8371SZi Yan 1712bf929152SKirill A. Shutemov spin_unlock(ptl); 1713616b8371SZi Yan if (flush_needed) 1714e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1715479f0abbSKirill A. Shutemov } 1716da146769SKirill A. Shutemov return 1; 171771e3aac0SAndrea Arcangeli } 171871e3aac0SAndrea Arcangeli 17191dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 17201dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 17211dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 17221dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 17231dd38b6cSAneesh Kumar K.V { 17241dd38b6cSAneesh Kumar K.V /* 17251dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 17261dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 17271dd38b6cSAneesh Kumar K.V * 17281dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 17291dd38b6cSAneesh Kumar K.V */ 17301dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 17311dd38b6cSAneesh Kumar K.V } 17321dd38b6cSAneesh Kumar K.V #endif 17331dd38b6cSAneesh Kumar K.V 1734ab6e3d09SNaoya Horiguchi static pmd_t move_soft_dirty_pmd(pmd_t pmd) 1735ab6e3d09SNaoya Horiguchi { 1736ab6e3d09SNaoya Horiguchi #ifdef CONFIG_MEM_SOFT_DIRTY 1737ab6e3d09SNaoya Horiguchi if (unlikely(is_pmd_migration_entry(pmd))) 1738ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 1739ab6e3d09SNaoya Horiguchi else if (pmd_present(pmd)) 1740ab6e3d09SNaoya Horiguchi pmd = pmd_mksoft_dirty(pmd); 1741ab6e3d09SNaoya Horiguchi #endif 1742ab6e3d09SNaoya Horiguchi return pmd; 1743ab6e3d09SNaoya Horiguchi } 1744ab6e3d09SNaoya Horiguchi 1745bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 1746b8aa9d9dSWei Yang unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) 174737a1c49aSAndrea Arcangeli { 1748bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 174937a1c49aSAndrea Arcangeli pmd_t pmd; 175037a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 17515d190420SAaron Lu bool force_flush = false; 175237a1c49aSAndrea Arcangeli 175337a1c49aSAndrea Arcangeli /* 175437a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 175537a1c49aSAndrea Arcangeli * should have release it. 175637a1c49aSAndrea Arcangeli */ 175737a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 175837a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 17594b471e88SKirill A. Shutemov return false; 176037a1c49aSAndrea Arcangeli } 176137a1c49aSAndrea Arcangeli 1762bf929152SKirill A. Shutemov /* 1763bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1764c1e8d7c6SMichel Lespinasse * ptlocks because exclusive mmap_lock prevents deadlock. 1765bf929152SKirill A. Shutemov */ 1766b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1767b6ec57f4SKirill A. Shutemov if (old_ptl) { 1768bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1769bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1770bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 17718809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1772eb66ae03SLinus Torvalds if (pmd_present(pmd)) 1773a2ce2666SAaron Lu force_flush = true; 177437a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 17753592806cSKirill A. Shutemov 17761dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1777b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 17783592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 17793592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 17803592806cSKirill A. Shutemov } 1781ab6e3d09SNaoya Horiguchi pmd = move_soft_dirty_pmd(pmd); 1782ab6e3d09SNaoya Horiguchi set_pmd_at(mm, new_addr, new_pmd, pmd); 17835d190420SAaron Lu if (force_flush) 17845d190420SAaron Lu flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 1785eb66ae03SLinus Torvalds if (new_ptl != old_ptl) 1786eb66ae03SLinus Torvalds spin_unlock(new_ptl); 1787bf929152SKirill A. Shutemov spin_unlock(old_ptl); 17884b471e88SKirill A. Shutemov return true; 178937a1c49aSAndrea Arcangeli } 17904b471e88SKirill A. Shutemov return false; 179137a1c49aSAndrea Arcangeli } 179237a1c49aSAndrea Arcangeli 1793f123d74aSMel Gorman /* 1794f123d74aSMel Gorman * Returns 1795f123d74aSMel Gorman * - 0 if PMD could not be locked 1796f123d74aSMel Gorman * - 1 if PMD was locked but protections unchange and TLB flush unnecessary 1797f123d74aSMel Gorman * - HPAGE_PMD_NR is protections changed and TLB flush necessary 1798f123d74aSMel Gorman */ 1799cd7548abSJohannes Weiner int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 180058705444SPeter Xu unsigned long addr, pgprot_t newprot, unsigned long cp_flags) 1801cd7548abSJohannes Weiner { 1802cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1803bf929152SKirill A. Shutemov spinlock_t *ptl; 18040a85e51dSKirill A. Shutemov pmd_t entry; 18050a85e51dSKirill A. Shutemov bool preserve_write; 18060a85e51dSKirill A. Shutemov int ret; 180758705444SPeter Xu bool prot_numa = cp_flags & MM_CP_PROT_NUMA; 1808292924b2SPeter Xu bool uffd_wp = cp_flags & MM_CP_UFFD_WP; 1809292924b2SPeter Xu bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; 1810cd7548abSJohannes Weiner 1811b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 18120a85e51dSKirill A. Shutemov if (!ptl) 18130a85e51dSKirill A. Shutemov return 0; 18140a85e51dSKirill A. Shutemov 18150a85e51dSKirill A. Shutemov preserve_write = prot_numa && pmd_write(*pmd); 1816ba68bc01SMel Gorman ret = 1; 1817e944fd67SMel Gorman 181884c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 181984c3fc4eSZi Yan if (is_swap_pmd(*pmd)) { 182084c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(*pmd); 182184c3fc4eSZi Yan 182284c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd)); 182384c3fc4eSZi Yan if (is_write_migration_entry(entry)) { 182484c3fc4eSZi Yan pmd_t newpmd; 182584c3fc4eSZi Yan /* 182684c3fc4eSZi Yan * A protection check is difficult so 182784c3fc4eSZi Yan * just be safe and disable write 182884c3fc4eSZi Yan */ 182984c3fc4eSZi Yan make_migration_entry_read(&entry); 183084c3fc4eSZi Yan newpmd = swp_entry_to_pmd(entry); 1831ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pmd)) 1832ab6e3d09SNaoya Horiguchi newpmd = pmd_swp_mksoft_dirty(newpmd); 183384c3fc4eSZi Yan set_pmd_at(mm, addr, pmd, newpmd); 183484c3fc4eSZi Yan } 183584c3fc4eSZi Yan goto unlock; 183684c3fc4eSZi Yan } 183784c3fc4eSZi Yan #endif 183884c3fc4eSZi Yan 1839e944fd67SMel Gorman /* 1840e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1841e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1842e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1843e944fd67SMel Gorman */ 18440a85e51dSKirill A. Shutemov if (prot_numa && is_huge_zero_pmd(*pmd)) 18450a85e51dSKirill A. Shutemov goto unlock; 1846e944fd67SMel Gorman 18470a85e51dSKirill A. Shutemov if (prot_numa && pmd_protnone(*pmd)) 18480a85e51dSKirill A. Shutemov goto unlock; 18490a85e51dSKirill A. Shutemov 1850ced10803SKirill A. Shutemov /* 18513e4e28c5SMichel Lespinasse * In case prot_numa, we are under mmap_read_lock(mm). It's critical 1852ced10803SKirill A. Shutemov * to not clear pmd intermittently to avoid race with MADV_DONTNEED 18533e4e28c5SMichel Lespinasse * which is also under mmap_read_lock(mm): 1854ced10803SKirill A. Shutemov * 1855ced10803SKirill A. Shutemov * CPU0: CPU1: 1856ced10803SKirill A. Shutemov * change_huge_pmd(prot_numa=1) 1857ced10803SKirill A. Shutemov * pmdp_huge_get_and_clear_notify() 1858ced10803SKirill A. Shutemov * madvise_dontneed() 1859ced10803SKirill A. Shutemov * zap_pmd_range() 1860ced10803SKirill A. Shutemov * pmd_trans_huge(*pmd) == 0 (without ptl) 1861ced10803SKirill A. Shutemov * // skip the pmd 1862ced10803SKirill A. Shutemov * set_pmd_at(); 1863ced10803SKirill A. Shutemov * // pmd is re-established 1864ced10803SKirill A. Shutemov * 1865ced10803SKirill A. Shutemov * The race makes MADV_DONTNEED miss the huge pmd and don't clear it 1866ced10803SKirill A. Shutemov * which may break userspace. 1867ced10803SKirill A. Shutemov * 1868ced10803SKirill A. Shutemov * pmdp_invalidate() is required to make sure we don't miss 1869ced10803SKirill A. Shutemov * dirty/young flags set by hardware. 1870ced10803SKirill A. Shutemov */ 1871a3cf988fSKirill A. Shutemov entry = pmdp_invalidate(vma, addr, pmd); 1872ced10803SKirill A. Shutemov 1873cd7548abSJohannes Weiner entry = pmd_modify(entry, newprot); 1874b191f9b1SMel Gorman if (preserve_write) 1875288bc549SAneesh Kumar K.V entry = pmd_mk_savedwrite(entry); 1876292924b2SPeter Xu if (uffd_wp) { 1877292924b2SPeter Xu entry = pmd_wrprotect(entry); 1878292924b2SPeter Xu entry = pmd_mkuffd_wp(entry); 1879292924b2SPeter Xu } else if (uffd_wp_resolve) { 1880292924b2SPeter Xu /* 1881292924b2SPeter Xu * Leave the write bit to be handled by PF interrupt 1882292924b2SPeter Xu * handler, then things like COW could be properly 1883292924b2SPeter Xu * handled. 1884292924b2SPeter Xu */ 1885292924b2SPeter Xu entry = pmd_clear_uffd_wp(entry); 1886292924b2SPeter Xu } 1887f123d74aSMel Gorman ret = HPAGE_PMD_NR; 188856eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 18890a85e51dSKirill A. Shutemov BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); 18900a85e51dSKirill A. Shutemov unlock: 1891bf929152SKirill A. Shutemov spin_unlock(ptl); 1892cd7548abSJohannes Weiner return ret; 1893cd7548abSJohannes Weiner } 1894cd7548abSJohannes Weiner 1895025c5b24SNaoya Horiguchi /* 18968f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 1897025c5b24SNaoya Horiguchi * 18988f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 18998f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 1900025c5b24SNaoya Horiguchi */ 1901b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1902025c5b24SNaoya Horiguchi { 1903b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 1904b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 190584c3fc4eSZi Yan if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || 190684c3fc4eSZi Yan pmd_devmap(*pmd))) 1907b6ec57f4SKirill A. Shutemov return ptl; 1908b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 1909b6ec57f4SKirill A. Shutemov return NULL; 1910025c5b24SNaoya Horiguchi } 1911025c5b24SNaoya Horiguchi 1912a00cc7d9SMatthew Wilcox /* 1913a00cc7d9SMatthew Wilcox * Returns true if a given pud maps a thp, false otherwise. 1914a00cc7d9SMatthew Wilcox * 1915a00cc7d9SMatthew Wilcox * Note that if it returns true, this routine returns without unlocking page 1916a00cc7d9SMatthew Wilcox * table lock. So callers must unlock it. 1917a00cc7d9SMatthew Wilcox */ 1918a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 1919a00cc7d9SMatthew Wilcox { 1920a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1921a00cc7d9SMatthew Wilcox 1922a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 1923a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 1924a00cc7d9SMatthew Wilcox return ptl; 1925a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1926a00cc7d9SMatthew Wilcox return NULL; 1927a00cc7d9SMatthew Wilcox } 1928a00cc7d9SMatthew Wilcox 1929a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1930a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 1931a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 1932a00cc7d9SMatthew Wilcox { 1933a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1934a00cc7d9SMatthew Wilcox 1935a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 1936a00cc7d9SMatthew Wilcox if (!ptl) 1937a00cc7d9SMatthew Wilcox return 0; 1938a00cc7d9SMatthew Wilcox /* 1939a00cc7d9SMatthew Wilcox * For architectures like ppc64 we look at deposited pgtable 1940a00cc7d9SMatthew Wilcox * when calling pudp_huge_get_and_clear. So do the 1941a00cc7d9SMatthew Wilcox * pgtable_trans_huge_withdraw after finishing pudp related 1942a00cc7d9SMatthew Wilcox * operations. 1943a00cc7d9SMatthew Wilcox */ 194470516b93SQian Cai pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); 1945a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 19462484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 1947a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1948a00cc7d9SMatthew Wilcox /* No zero page support yet */ 1949a00cc7d9SMatthew Wilcox } else { 1950a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 1951a00cc7d9SMatthew Wilcox BUG(); 1952a00cc7d9SMatthew Wilcox } 1953a00cc7d9SMatthew Wilcox return 1; 1954a00cc7d9SMatthew Wilcox } 1955a00cc7d9SMatthew Wilcox 1956a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 1957a00cc7d9SMatthew Wilcox unsigned long haddr) 1958a00cc7d9SMatthew Wilcox { 1959a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 1960a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 1961a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 1962a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 1963a00cc7d9SMatthew Wilcox 1964ce9311cfSYisheng Xie count_vm_event(THP_SPLIT_PUD); 1965a00cc7d9SMatthew Wilcox 1966a00cc7d9SMatthew Wilcox pudp_huge_clear_flush_notify(vma, haddr, pud); 1967a00cc7d9SMatthew Wilcox } 1968a00cc7d9SMatthew Wilcox 1969a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 1970a00cc7d9SMatthew Wilcox unsigned long address) 1971a00cc7d9SMatthew Wilcox { 1972a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1973ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1974a00cc7d9SMatthew Wilcox 19757269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 19766f4f13e8SJérôme Glisse address & HPAGE_PUD_MASK, 1977ac46d4f3SJérôme Glisse (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); 1978ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1979ac46d4f3SJérôme Glisse ptl = pud_lock(vma->vm_mm, pud); 1980a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 1981a00cc7d9SMatthew Wilcox goto out; 1982ac46d4f3SJérôme Glisse __split_huge_pud_locked(vma, pud, range.start); 1983a00cc7d9SMatthew Wilcox 1984a00cc7d9SMatthew Wilcox out: 1985a00cc7d9SMatthew Wilcox spin_unlock(ptl); 19864645b9feSJérôme Glisse /* 19874645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 19884645b9feSJérôme Glisse * the above pudp_huge_clear_flush_notify() did already call it. 19894645b9feSJérôme Glisse */ 1990ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 1991a00cc7d9SMatthew Wilcox } 1992a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1993a00cc7d9SMatthew Wilcox 1994eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 1995eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 1996eef1b3baSKirill A. Shutemov { 1997eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 1998eef1b3baSKirill A. Shutemov pgtable_t pgtable; 1999eef1b3baSKirill A. Shutemov pmd_t _pmd; 2000eef1b3baSKirill A. Shutemov int i; 2001eef1b3baSKirill A. Shutemov 20020f10851eSJérôme Glisse /* 20030f10851eSJérôme Glisse * Leave pmd empty until pte is filled note that it is fine to delay 20040f10851eSJérôme Glisse * notification until mmu_notifier_invalidate_range_end() as we are 20050f10851eSJérôme Glisse * replacing a zero pmd write protected page with a zero pte write 20060f10851eSJérôme Glisse * protected page. 20070f10851eSJérôme Glisse * 2008ad56b738SMike Rapoport * See Documentation/vm/mmu_notifier.rst 20090f10851eSJérôme Glisse */ 20100f10851eSJérôme Glisse pmdp_huge_clear_flush(vma, haddr, pmd); 2011eef1b3baSKirill A. Shutemov 2012eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2013eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2014eef1b3baSKirill A. Shutemov 2015eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 2016eef1b3baSKirill A. Shutemov pte_t *pte, entry; 2017eef1b3baSKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 2018eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 2019eef1b3baSKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 2020eef1b3baSKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 2021eef1b3baSKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 2022eef1b3baSKirill A. Shutemov pte_unmap(pte); 2023eef1b3baSKirill A. Shutemov } 2024eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2025eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2026eef1b3baSKirill A. Shutemov } 2027eef1b3baSKirill A. Shutemov 2028eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 2029ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 2030eef1b3baSKirill A. Shutemov { 2031eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2032eef1b3baSKirill A. Shutemov struct page *page; 2033eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2034423ac9afSAneesh Kumar K.V pmd_t old_pmd, _pmd; 2035292924b2SPeter Xu bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; 20362ac015e2SKirill A. Shutemov unsigned long addr; 2037eef1b3baSKirill A. Shutemov int i; 2038eef1b3baSKirill A. Shutemov 2039eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 2040eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2041eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 204284c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) 204384c3fc4eSZi Yan && !pmd_devmap(*pmd)); 2044eef1b3baSKirill A. Shutemov 2045eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 2046eef1b3baSKirill A. Shutemov 2047d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 2048d21b9e57SKirill A. Shutemov _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); 2049953c66c2SAneesh Kumar K.V /* 2050953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 2051953c66c2SAneesh Kumar K.V * just go ahead and zap it 2052953c66c2SAneesh Kumar K.V */ 2053953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 2054953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 20552484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) 2056d21b9e57SKirill A. Shutemov return; 2057d21b9e57SKirill A. Shutemov page = pmd_page(_pmd); 2058e1f1b157SHugh Dickins if (!PageDirty(page) && pmd_dirty(_pmd)) 2059e1f1b157SHugh Dickins set_page_dirty(page); 2060d21b9e57SKirill A. Shutemov if (!PageReferenced(page) && pmd_young(_pmd)) 2061d21b9e57SKirill A. Shutemov SetPageReferenced(page); 2062d21b9e57SKirill A. Shutemov page_remove_rmap(page, true); 2063d21b9e57SKirill A. Shutemov put_page(page); 2064fadae295SYang Shi add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); 2065eef1b3baSKirill A. Shutemov return; 2066ec0abae6SRalph Campbell } else if (pmd_trans_huge(*pmd) && is_huge_zero_pmd(*pmd)) { 20674645b9feSJérôme Glisse /* 20684645b9feSJérôme Glisse * FIXME: Do we want to invalidate secondary mmu by calling 20694645b9feSJérôme Glisse * mmu_notifier_invalidate_range() see comments below inside 20704645b9feSJérôme Glisse * __split_huge_pmd() ? 20714645b9feSJérôme Glisse * 20724645b9feSJérôme Glisse * We are going from a zero huge page write protected to zero 20734645b9feSJérôme Glisse * small page also write protected so it does not seems useful 20744645b9feSJérôme Glisse * to invalidate secondary mmu at this time. 20754645b9feSJérôme Glisse */ 2076eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 2077eef1b3baSKirill A. Shutemov } 2078eef1b3baSKirill A. Shutemov 2079423ac9afSAneesh Kumar K.V /* 2080423ac9afSAneesh Kumar K.V * Up to this point the pmd is present and huge and userland has the 2081423ac9afSAneesh Kumar K.V * whole access to the hugepage during the split (which happens in 2082423ac9afSAneesh Kumar K.V * place). If we overwrite the pmd with the not-huge version pointing 2083423ac9afSAneesh Kumar K.V * to the pte here (which of course we could if all CPUs were bug 2084423ac9afSAneesh Kumar K.V * free), userland could trigger a small page size TLB miss on the 2085423ac9afSAneesh Kumar K.V * small sized TLB while the hugepage TLB entry is still established in 2086423ac9afSAneesh Kumar K.V * the huge TLB. Some CPU doesn't like that. 208742742d9bSAlexander A. Klimov * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum 208842742d9bSAlexander A. Klimov * 383 on page 105. Intel should be safe but is also warns that it's 2089423ac9afSAneesh Kumar K.V * only safe if the permission and cache attributes of the two entries 2090423ac9afSAneesh Kumar K.V * loaded in the two TLB is identical (which should be the case here). 2091423ac9afSAneesh Kumar K.V * But it is generally safer to never allow small and huge TLB entries 2092423ac9afSAneesh Kumar K.V * for the same virtual address to be loaded simultaneously. So instead 2093423ac9afSAneesh Kumar K.V * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2094423ac9afSAneesh Kumar K.V * current pmd notpresent (atomically because here the pmd_trans_huge 2095423ac9afSAneesh Kumar K.V * must remain set at all times on the pmd until the split is complete 2096423ac9afSAneesh Kumar K.V * for this pmd), then we flush the SMP TLB and finally we write the 2097423ac9afSAneesh Kumar K.V * non-huge version of the pmd entry with pmd_populate. 2098423ac9afSAneesh Kumar K.V */ 2099423ac9afSAneesh Kumar K.V old_pmd = pmdp_invalidate(vma, haddr, pmd); 2100423ac9afSAneesh Kumar K.V 2101423ac9afSAneesh Kumar K.V pmd_migration = is_pmd_migration_entry(old_pmd); 21022e83ee1dSPeter Xu if (unlikely(pmd_migration)) { 210384c3fc4eSZi Yan swp_entry_t entry; 210484c3fc4eSZi Yan 2105423ac9afSAneesh Kumar K.V entry = pmd_to_swp_entry(old_pmd); 210684c3fc4eSZi Yan page = pfn_to_page(swp_offset(entry)); 21072e83ee1dSPeter Xu write = is_write_migration_entry(entry); 21082e83ee1dSPeter Xu young = false; 21092e83ee1dSPeter Xu soft_dirty = pmd_swp_soft_dirty(old_pmd); 2110f45ec5ffSPeter Xu uffd_wp = pmd_swp_uffd_wp(old_pmd); 21112e83ee1dSPeter Xu } else { 2112423ac9afSAneesh Kumar K.V page = pmd_page(old_pmd); 2113423ac9afSAneesh Kumar K.V if (pmd_dirty(old_pmd)) 2114423ac9afSAneesh Kumar K.V SetPageDirty(page); 2115423ac9afSAneesh Kumar K.V write = pmd_write(old_pmd); 2116423ac9afSAneesh Kumar K.V young = pmd_young(old_pmd); 2117423ac9afSAneesh Kumar K.V soft_dirty = pmd_soft_dirty(old_pmd); 2118292924b2SPeter Xu uffd_wp = pmd_uffd_wp(old_pmd); 21192e83ee1dSPeter Xu } 21202e83ee1dSPeter Xu VM_BUG_ON_PAGE(!page_count(page), page); 21212e83ee1dSPeter Xu page_ref_add(page, HPAGE_PMD_NR - 1); 2122eef1b3baSKirill A. Shutemov 2123423ac9afSAneesh Kumar K.V /* 2124423ac9afSAneesh Kumar K.V * Withdraw the table only after we mark the pmd entry invalid. 2125423ac9afSAneesh Kumar K.V * This's critical for some architectures (Power). 2126423ac9afSAneesh Kumar K.V */ 2127eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2128eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2129eef1b3baSKirill A. Shutemov 21302ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2131eef1b3baSKirill A. Shutemov pte_t entry, *pte; 2132eef1b3baSKirill A. Shutemov /* 2133eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 2134eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 2135eef1b3baSKirill A. Shutemov * permissions across VMAs. 2136eef1b3baSKirill A. Shutemov */ 213784c3fc4eSZi Yan if (freeze || pmd_migration) { 2138ba988280SKirill A. Shutemov swp_entry_t swp_entry; 2139ba988280SKirill A. Shutemov swp_entry = make_migration_entry(page + i, write); 2140ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 2141804dd150SAndrea Arcangeli if (soft_dirty) 2142804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 2143f45ec5ffSPeter Xu if (uffd_wp) 2144f45ec5ffSPeter Xu entry = pte_swp_mkuffd_wp(entry); 2145ba988280SKirill A. Shutemov } else { 21466d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 2147b8d3c4c3SMinchan Kim entry = maybe_mkwrite(entry, vma); 2148eef1b3baSKirill A. Shutemov if (!write) 2149eef1b3baSKirill A. Shutemov entry = pte_wrprotect(entry); 2150eef1b3baSKirill A. Shutemov if (!young) 2151eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 2152804dd150SAndrea Arcangeli if (soft_dirty) 2153804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 2154292924b2SPeter Xu if (uffd_wp) 2155292924b2SPeter Xu entry = pte_mkuffd_wp(entry); 2156ba988280SKirill A. Shutemov } 21572ac015e2SKirill A. Shutemov pte = pte_offset_map(&_pmd, addr); 2158eef1b3baSKirill A. Shutemov BUG_ON(!pte_none(*pte)); 21592ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 2160ec0abae6SRalph Campbell if (!pmd_migration) 2161eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 2162eef1b3baSKirill A. Shutemov pte_unmap(pte); 2163eef1b3baSKirill A. Shutemov } 2164eef1b3baSKirill A. Shutemov 2165ec0abae6SRalph Campbell if (!pmd_migration) { 2166eef1b3baSKirill A. Shutemov /* 2167eef1b3baSKirill A. Shutemov * Set PG_double_map before dropping compound_mapcount to avoid 2168eef1b3baSKirill A. Shutemov * false-negative page_mapped(). 2169eef1b3baSKirill A. Shutemov */ 2170ec0abae6SRalph Campbell if (compound_mapcount(page) > 1 && 2171ec0abae6SRalph Campbell !TestSetPageDoubleMap(page)) { 2172eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2173eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 2174eef1b3baSKirill A. Shutemov } 2175eef1b3baSKirill A. Shutemov 2176468c3982SJohannes Weiner lock_page_memcg(page); 2177eef1b3baSKirill A. Shutemov if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { 2178eef1b3baSKirill A. Shutemov /* Last compound_mapcount is gone. */ 2179468c3982SJohannes Weiner __dec_lruvec_page_state(page, NR_ANON_THPS); 2180eef1b3baSKirill A. Shutemov if (TestClearPageDoubleMap(page)) { 2181eef1b3baSKirill A. Shutemov /* No need in mapcount reference anymore */ 2182eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2183eef1b3baSKirill A. Shutemov atomic_dec(&page[i]._mapcount); 2184eef1b3baSKirill A. Shutemov } 2185eef1b3baSKirill A. Shutemov } 2186468c3982SJohannes Weiner unlock_page_memcg(page); 2187ec0abae6SRalph Campbell } 2188eef1b3baSKirill A. Shutemov 2189eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2190eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2191e9b61f19SKirill A. Shutemov 2192e9b61f19SKirill A. Shutemov if (freeze) { 21932ac015e2SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) { 2194e9b61f19SKirill A. Shutemov page_remove_rmap(page + i, false); 2195e9b61f19SKirill A. Shutemov put_page(page + i); 2196e9b61f19SKirill A. Shutemov } 2197e9b61f19SKirill A. Shutemov } 2198eef1b3baSKirill A. Shutemov } 2199eef1b3baSKirill A. Shutemov 2200eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 220133f4751eSNaoya Horiguchi unsigned long address, bool freeze, struct page *page) 2202eef1b3baSKirill A. Shutemov { 2203eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2204ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2205c444eb56SAndrea Arcangeli bool was_locked = false; 2206c444eb56SAndrea Arcangeli pmd_t _pmd; 2207eef1b3baSKirill A. Shutemov 22087269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 22096f4f13e8SJérôme Glisse address & HPAGE_PMD_MASK, 2210ac46d4f3SJérôme Glisse (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); 2211ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2212ac46d4f3SJérôme Glisse ptl = pmd_lock(vma->vm_mm, pmd); 221333f4751eSNaoya Horiguchi 221433f4751eSNaoya Horiguchi /* 221533f4751eSNaoya Horiguchi * If caller asks to setup a migration entries, we need a page to check 221633f4751eSNaoya Horiguchi * pmd against. Otherwise we can end up replacing wrong page. 221733f4751eSNaoya Horiguchi */ 221833f4751eSNaoya Horiguchi VM_BUG_ON(freeze && !page); 2219c444eb56SAndrea Arcangeli if (page) { 2220c444eb56SAndrea Arcangeli VM_WARN_ON_ONCE(!PageLocked(page)); 2221c444eb56SAndrea Arcangeli was_locked = true; 2222c444eb56SAndrea Arcangeli if (page != pmd_page(*pmd)) 222333f4751eSNaoya Horiguchi goto out; 2224c444eb56SAndrea Arcangeli } 222533f4751eSNaoya Horiguchi 2226c444eb56SAndrea Arcangeli repeat: 22275c7fb56eSDan Williams if (pmd_trans_huge(*pmd)) { 2228c444eb56SAndrea Arcangeli if (!page) { 222933f4751eSNaoya Horiguchi page = pmd_page(*pmd); 2230c444eb56SAndrea Arcangeli if (unlikely(!trylock_page(page))) { 2231c444eb56SAndrea Arcangeli get_page(page); 2232c444eb56SAndrea Arcangeli _pmd = *pmd; 2233c444eb56SAndrea Arcangeli spin_unlock(ptl); 2234c444eb56SAndrea Arcangeli lock_page(page); 2235c444eb56SAndrea Arcangeli spin_lock(ptl); 2236c444eb56SAndrea Arcangeli if (unlikely(!pmd_same(*pmd, _pmd))) { 2237c444eb56SAndrea Arcangeli unlock_page(page); 2238c444eb56SAndrea Arcangeli put_page(page); 2239c444eb56SAndrea Arcangeli page = NULL; 2240c444eb56SAndrea Arcangeli goto repeat; 2241c444eb56SAndrea Arcangeli } 2242c444eb56SAndrea Arcangeli put_page(page); 2243c444eb56SAndrea Arcangeli } 2244c444eb56SAndrea Arcangeli } 2245e90309c9SKirill A. Shutemov if (PageMlocked(page)) 22465f737714SKirill A. Shutemov clear_page_mlock(page); 224784c3fc4eSZi Yan } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) 22485c7fb56eSDan Williams goto out; 2249ac46d4f3SJérôme Glisse __split_huge_pmd_locked(vma, pmd, range.start, freeze); 2250e90309c9SKirill A. Shutemov out: 2251eef1b3baSKirill A. Shutemov spin_unlock(ptl); 2252c444eb56SAndrea Arcangeli if (!was_locked && page) 2253c444eb56SAndrea Arcangeli unlock_page(page); 22544645b9feSJérôme Glisse /* 22554645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback. 22564645b9feSJérôme Glisse * They are 3 cases to consider inside __split_huge_pmd_locked(): 22574645b9feSJérôme Glisse * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious 22584645b9feSJérôme Glisse * 2) __split_huge_zero_page_pmd() read only zero page and any write 22594645b9feSJérôme Glisse * fault will trigger a flush_notify before pointing to a new page 22604645b9feSJérôme Glisse * (it is fine if the secondary mmu keeps pointing to the old zero 22614645b9feSJérôme Glisse * page in the meantime) 22624645b9feSJérôme Glisse * 3) Split a huge pmd into pte pointing to the same page. No need 22634645b9feSJérôme Glisse * to invalidate secondary tlb entry they are all still valid. 22644645b9feSJérôme Glisse * any further changes to individual pte will notify. So no need 22654645b9feSJérôme Glisse * to call mmu_notifier->invalidate_range() 22664645b9feSJérôme Glisse */ 2267ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 2268eef1b3baSKirill A. Shutemov } 2269eef1b3baSKirill A. Shutemov 2270fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2271fec89c10SKirill A. Shutemov bool freeze, struct page *page) 227294fcc585SAndrea Arcangeli { 2273f72e7dcdSHugh Dickins pgd_t *pgd; 2274c2febafcSKirill A. Shutemov p4d_t *p4d; 2275f72e7dcdSHugh Dickins pud_t *pud; 227694fcc585SAndrea Arcangeli pmd_t *pmd; 227794fcc585SAndrea Arcangeli 227878ddc534SKirill A. Shutemov pgd = pgd_offset(vma->vm_mm, address); 2279f72e7dcdSHugh Dickins if (!pgd_present(*pgd)) 2280f72e7dcdSHugh Dickins return; 2281f72e7dcdSHugh Dickins 2282c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, address); 2283c2febafcSKirill A. Shutemov if (!p4d_present(*p4d)) 2284c2febafcSKirill A. Shutemov return; 2285c2febafcSKirill A. Shutemov 2286c2febafcSKirill A. Shutemov pud = pud_offset(p4d, address); 2287f72e7dcdSHugh Dickins if (!pud_present(*pud)) 2288f72e7dcdSHugh Dickins return; 2289f72e7dcdSHugh Dickins 2290f72e7dcdSHugh Dickins pmd = pmd_offset(pud, address); 2291fec89c10SKirill A. Shutemov 229233f4751eSNaoya Horiguchi __split_huge_pmd(vma, pmd, address, freeze, page); 229394fcc585SAndrea Arcangeli } 229494fcc585SAndrea Arcangeli 2295e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 229694fcc585SAndrea Arcangeli unsigned long start, 229794fcc585SAndrea Arcangeli unsigned long end, 229894fcc585SAndrea Arcangeli long adjust_next) 229994fcc585SAndrea Arcangeli { 230094fcc585SAndrea Arcangeli /* 230194fcc585SAndrea Arcangeli * If the new start address isn't hpage aligned and it could 230294fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 230394fcc585SAndrea Arcangeli * an huge pmd. 230494fcc585SAndrea Arcangeli */ 230594fcc585SAndrea Arcangeli if (start & ~HPAGE_PMD_MASK && 230694fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) >= vma->vm_start && 230794fcc585SAndrea Arcangeli (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 2308fec89c10SKirill A. Shutemov split_huge_pmd_address(vma, start, false, NULL); 230994fcc585SAndrea Arcangeli 231094fcc585SAndrea Arcangeli /* 231194fcc585SAndrea Arcangeli * If the new end address isn't hpage aligned and it could 231294fcc585SAndrea Arcangeli * previously contain an hugepage: check if we need to split 231394fcc585SAndrea Arcangeli * an huge pmd. 231494fcc585SAndrea Arcangeli */ 231594fcc585SAndrea Arcangeli if (end & ~HPAGE_PMD_MASK && 231694fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) >= vma->vm_start && 231794fcc585SAndrea Arcangeli (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) 2318fec89c10SKirill A. Shutemov split_huge_pmd_address(vma, end, false, NULL); 231994fcc585SAndrea Arcangeli 232094fcc585SAndrea Arcangeli /* 232194fcc585SAndrea Arcangeli * If we're also updating the vma->vm_next->vm_start, if the new 2322f9d86a60SWei Yang * vm_next->vm_start isn't hpage aligned and it could previously 232394fcc585SAndrea Arcangeli * contain an hugepage: check if we need to split an huge pmd. 232494fcc585SAndrea Arcangeli */ 232594fcc585SAndrea Arcangeli if (adjust_next > 0) { 232694fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 232794fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 2328f9d86a60SWei Yang nstart += adjust_next; 232994fcc585SAndrea Arcangeli if (nstart & ~HPAGE_PMD_MASK && 233094fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) >= next->vm_start && 233194fcc585SAndrea Arcangeli (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) 2332fec89c10SKirill A. Shutemov split_huge_pmd_address(next, nstart, false, NULL); 233394fcc585SAndrea Arcangeli } 233494fcc585SAndrea Arcangeli } 2335e9b61f19SKirill A. Shutemov 2336906f9cdfSHugh Dickins static void unmap_page(struct page *page) 2337e9b61f19SKirill A. Shutemov { 2338013339dfSShakeel Butt enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | 2339c7ab0d2fSKirill A. Shutemov TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; 2340666e5a40SMinchan Kim bool unmap_success; 2341e9b61f19SKirill A. Shutemov 2342e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageHead(page), page); 2343e9b61f19SKirill A. Shutemov 2344baa355fdSKirill A. Shutemov if (PageAnon(page)) 2345b5ff8161SNaoya Horiguchi ttu_flags |= TTU_SPLIT_FREEZE; 2346baa355fdSKirill A. Shutemov 2347666e5a40SMinchan Kim unmap_success = try_to_unmap(page, ttu_flags); 2348666e5a40SMinchan Kim VM_BUG_ON_PAGE(!unmap_success, page); 2349bd56086fSKirill A. Shutemov } 2350bd56086fSKirill A. Shutemov 23518cce5475SKirill A. Shutemov static void remap_page(struct page *page, unsigned int nr) 2352e9b61f19SKirill A. Shutemov { 2353fec89c10SKirill A. Shutemov int i; 2354ace71a19SKirill A. Shutemov if (PageTransHuge(page)) { 2355ace71a19SKirill A. Shutemov remove_migration_ptes(page, page, true); 2356ace71a19SKirill A. Shutemov } else { 23578cce5475SKirill A. Shutemov for (i = 0; i < nr; i++) 2358fec89c10SKirill A. Shutemov remove_migration_ptes(page + i, page + i, true); 2359e9b61f19SKirill A. Shutemov } 2360ace71a19SKirill A. Shutemov } 2361e9b61f19SKirill A. Shutemov 23628df651c7SKirill A. Shutemov static void __split_huge_page_tail(struct page *head, int tail, 2363e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2364e9b61f19SKirill A. Shutemov { 2365e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 2366e9b61f19SKirill A. Shutemov 23678df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2368e9b61f19SKirill A. Shutemov 2369e9b61f19SKirill A. Shutemov /* 2370605ca5edSKonstantin Khlebnikov * Clone page flags before unfreezing refcount. 2371605ca5edSKonstantin Khlebnikov * 2372605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow flags change, 2373605ca5edSKonstantin Khlebnikov * for exmaple lock_page() which set PG_waiters. 2374e9b61f19SKirill A. Shutemov */ 2375e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2376e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2377e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2378e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 237938d8b4e6SHuang Ying (1L << PG_swapcache) | 2380e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2381e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2382e9b61f19SKirill A. Shutemov (1L << PG_active) | 23831899ad18SJohannes Weiner (1L << PG_workingset) | 2384e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2385b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 238672e6afa0SCatalin Marinas #ifdef CONFIG_64BIT 238772e6afa0SCatalin Marinas (1L << PG_arch_2) | 238872e6afa0SCatalin Marinas #endif 2389b8d3c4c3SMinchan Kim (1L << PG_dirty))); 2390e9b61f19SKirill A. Shutemov 2391173d9d9fSHugh Dickins /* ->mapping in first tail page is compound_mapcount */ 2392173d9d9fSHugh Dickins VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2393173d9d9fSHugh Dickins page_tail); 2394173d9d9fSHugh Dickins page_tail->mapping = head->mapping; 2395173d9d9fSHugh Dickins page_tail->index = head->index + tail; 2396173d9d9fSHugh Dickins 2397605ca5edSKonstantin Khlebnikov /* Page flags must be visible before we make the page non-compound. */ 2398e9b61f19SKirill A. Shutemov smp_wmb(); 2399e9b61f19SKirill A. Shutemov 2400605ca5edSKonstantin Khlebnikov /* 2401605ca5edSKonstantin Khlebnikov * Clear PageTail before unfreezing page refcount. 2402605ca5edSKonstantin Khlebnikov * 2403605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow put_page() 2404605ca5edSKonstantin Khlebnikov * which needs correct compound_head(). 2405605ca5edSKonstantin Khlebnikov */ 2406e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2407e9b61f19SKirill A. Shutemov 2408605ca5edSKonstantin Khlebnikov /* Finally unfreeze refcount. Additional reference from page cache. */ 2409605ca5edSKonstantin Khlebnikov page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || 2410605ca5edSKonstantin Khlebnikov PageSwapCache(head))); 2411605ca5edSKonstantin Khlebnikov 2412e9b61f19SKirill A. Shutemov if (page_is_young(head)) 2413e9b61f19SKirill A. Shutemov set_page_young(page_tail); 2414e9b61f19SKirill A. Shutemov if (page_is_idle(head)) 2415e9b61f19SKirill A. Shutemov set_page_idle(page_tail); 2416e9b61f19SKirill A. Shutemov 2417e9b61f19SKirill A. Shutemov page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); 241894723aafSMichal Hocko 241994723aafSMichal Hocko /* 242094723aafSMichal Hocko * always add to the tail because some iterators expect new 242194723aafSMichal Hocko * pages to show after the currently processed elements - e.g. 242294723aafSMichal Hocko * migrate_pages 242394723aafSMichal Hocko */ 2424e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2425e9b61f19SKirill A. Shutemov } 2426e9b61f19SKirill A. Shutemov 2427baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2428006d3ff2SHugh Dickins pgoff_t end, unsigned long flags) 2429e9b61f19SKirill A. Shutemov { 2430e9b61f19SKirill A. Shutemov struct page *head = compound_head(page); 2431f4b7e272SAndrey Ryabinin pg_data_t *pgdat = page_pgdat(head); 2432e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 24334101196bSMatthew Wilcox (Oracle) struct address_space *swap_cache = NULL; 24344101196bSMatthew Wilcox (Oracle) unsigned long offset = 0; 24358cce5475SKirill A. Shutemov unsigned int nr = thp_nr_pages(head); 24368df651c7SKirill A. Shutemov int i; 2437e9b61f19SKirill A. Shutemov 2438f4b7e272SAndrey Ryabinin lruvec = mem_cgroup_page_lruvec(head, pgdat); 2439e9b61f19SKirill A. Shutemov 2440e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2441e9b61f19SKirill A. Shutemov mem_cgroup_split_huge_fixup(head); 2442e9b61f19SKirill A. Shutemov 24434101196bSMatthew Wilcox (Oracle) if (PageAnon(head) && PageSwapCache(head)) { 24444101196bSMatthew Wilcox (Oracle) swp_entry_t entry = { .val = page_private(head) }; 24454101196bSMatthew Wilcox (Oracle) 24464101196bSMatthew Wilcox (Oracle) offset = swp_offset(entry); 24474101196bSMatthew Wilcox (Oracle) swap_cache = swap_address_space(entry); 24484101196bSMatthew Wilcox (Oracle) xa_lock(&swap_cache->i_pages); 24494101196bSMatthew Wilcox (Oracle) } 24504101196bSMatthew Wilcox (Oracle) 24518cce5475SKirill A. Shutemov for (i = nr - 1; i >= 1; i--) { 24528df651c7SKirill A. Shutemov __split_huge_page_tail(head, i, lruvec, list); 2453baa355fdSKirill A. Shutemov /* Some pages can be beyond i_size: drop them from page cache */ 2454baa355fdSKirill A. Shutemov if (head[i].index >= end) { 24552d077d4bSHugh Dickins ClearPageDirty(head + i); 2456baa355fdSKirill A. Shutemov __delete_from_page_cache(head + i, NULL); 2457800d8c63SKirill A. Shutemov if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) 2458800d8c63SKirill A. Shutemov shmem_uncharge(head->mapping->host, 1); 2459baa355fdSKirill A. Shutemov put_page(head + i); 24604101196bSMatthew Wilcox (Oracle) } else if (!PageAnon(page)) { 24614101196bSMatthew Wilcox (Oracle) __xa_store(&head->mapping->i_pages, head[i].index, 24624101196bSMatthew Wilcox (Oracle) head + i, 0); 24634101196bSMatthew Wilcox (Oracle) } else if (swap_cache) { 24644101196bSMatthew Wilcox (Oracle) __xa_store(&swap_cache->i_pages, offset + i, 24654101196bSMatthew Wilcox (Oracle) head + i, 0); 2466baa355fdSKirill A. Shutemov } 2467baa355fdSKirill A. Shutemov } 2468e9b61f19SKirill A. Shutemov 2469e9b61f19SKirill A. Shutemov ClearPageCompound(head); 2470f7da677bSVlastimil Babka 24718cce5475SKirill A. Shutemov split_page_owner(head, nr); 2472f7da677bSVlastimil Babka 2473baa355fdSKirill A. Shutemov /* See comment in __split_huge_page_tail() */ 2474baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2475aa5dc07fSMatthew Wilcox /* Additional pin to swap cache */ 24764101196bSMatthew Wilcox (Oracle) if (PageSwapCache(head)) { 247738d8b4e6SHuang Ying page_ref_add(head, 2); 24784101196bSMatthew Wilcox (Oracle) xa_unlock(&swap_cache->i_pages); 24794101196bSMatthew Wilcox (Oracle) } else { 2480baa355fdSKirill A. Shutemov page_ref_inc(head); 24814101196bSMatthew Wilcox (Oracle) } 2482baa355fdSKirill A. Shutemov } else { 2483aa5dc07fSMatthew Wilcox /* Additional pin to page cache */ 2484baa355fdSKirill A. Shutemov page_ref_add(head, 2); 2485b93b0163SMatthew Wilcox xa_unlock(&head->mapping->i_pages); 2486baa355fdSKirill A. Shutemov } 2487baa355fdSKirill A. Shutemov 2488f4b7e272SAndrey Ryabinin spin_unlock_irqrestore(&pgdat->lru_lock, flags); 2489e9b61f19SKirill A. Shutemov 24908cce5475SKirill A. Shutemov remap_page(head, nr); 2491e9b61f19SKirill A. Shutemov 2492c4f9c701SHuang Ying if (PageSwapCache(head)) { 2493c4f9c701SHuang Ying swp_entry_t entry = { .val = page_private(head) }; 2494c4f9c701SHuang Ying 2495c4f9c701SHuang Ying split_swap_cluster(entry); 2496c4f9c701SHuang Ying } 2497c4f9c701SHuang Ying 24988cce5475SKirill A. Shutemov for (i = 0; i < nr; i++) { 2499e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2500e9b61f19SKirill A. Shutemov if (subpage == page) 2501e9b61f19SKirill A. Shutemov continue; 2502e9b61f19SKirill A. Shutemov unlock_page(subpage); 2503e9b61f19SKirill A. Shutemov 2504e9b61f19SKirill A. Shutemov /* 2505e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2506e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2507e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2508e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2509e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2510e9b61f19SKirill A. Shutemov */ 2511e9b61f19SKirill A. Shutemov put_page(subpage); 2512e9b61f19SKirill A. Shutemov } 2513e9b61f19SKirill A. Shutemov } 2514e9b61f19SKirill A. Shutemov 2515b20ce5e0SKirill A. Shutemov int total_mapcount(struct page *page) 2516b20ce5e0SKirill A. Shutemov { 251786b562b6SKirill A. Shutemov int i, compound, nr, ret; 2518b20ce5e0SKirill A. Shutemov 2519b20ce5e0SKirill A. Shutemov VM_BUG_ON_PAGE(PageTail(page), page); 2520b20ce5e0SKirill A. Shutemov 2521b20ce5e0SKirill A. Shutemov if (likely(!PageCompound(page))) 2522b20ce5e0SKirill A. Shutemov return atomic_read(&page->_mapcount) + 1; 2523b20ce5e0SKirill A. Shutemov 2524dd78feddSKirill A. Shutemov compound = compound_mapcount(page); 252586b562b6SKirill A. Shutemov nr = compound_nr(page); 2526b20ce5e0SKirill A. Shutemov if (PageHuge(page)) 2527dd78feddSKirill A. Shutemov return compound; 2528dd78feddSKirill A. Shutemov ret = compound; 252986b562b6SKirill A. Shutemov for (i = 0; i < nr; i++) 2530b20ce5e0SKirill A. Shutemov ret += atomic_read(&page[i]._mapcount) + 1; 2531dd78feddSKirill A. Shutemov /* File pages has compound_mapcount included in _mapcount */ 2532dd78feddSKirill A. Shutemov if (!PageAnon(page)) 253386b562b6SKirill A. Shutemov return ret - compound * nr; 2534b20ce5e0SKirill A. Shutemov if (PageDoubleMap(page)) 253586b562b6SKirill A. Shutemov ret -= nr; 2536b20ce5e0SKirill A. Shutemov return ret; 2537b20ce5e0SKirill A. Shutemov } 2538b20ce5e0SKirill A. Shutemov 2539e9b61f19SKirill A. Shutemov /* 25406d0a07edSAndrea Arcangeli * This calculates accurately how many mappings a transparent hugepage 25416d0a07edSAndrea Arcangeli * has (unlike page_mapcount() which isn't fully accurate). This full 25426d0a07edSAndrea Arcangeli * accuracy is primarily needed to know if copy-on-write faults can 25436d0a07edSAndrea Arcangeli * reuse the page and change the mapping to read-write instead of 25446d0a07edSAndrea Arcangeli * copying them. At the same time this returns the total_mapcount too. 25456d0a07edSAndrea Arcangeli * 25466d0a07edSAndrea Arcangeli * The function returns the highest mapcount any one of the subpages 25476d0a07edSAndrea Arcangeli * has. If the return value is one, even if different processes are 25486d0a07edSAndrea Arcangeli * mapping different subpages of the transparent hugepage, they can 25496d0a07edSAndrea Arcangeli * all reuse it, because each process is reusing a different subpage. 25506d0a07edSAndrea Arcangeli * 25516d0a07edSAndrea Arcangeli * The total_mapcount is instead counting all virtual mappings of the 25526d0a07edSAndrea Arcangeli * subpages. If the total_mapcount is equal to "one", it tells the 25536d0a07edSAndrea Arcangeli * caller all mappings belong to the same "mm" and in turn the 25546d0a07edSAndrea Arcangeli * anon_vma of the transparent hugepage can become the vma->anon_vma 25556d0a07edSAndrea Arcangeli * local one as no other process may be mapping any of the subpages. 25566d0a07edSAndrea Arcangeli * 25576d0a07edSAndrea Arcangeli * It would be more accurate to replace page_mapcount() with 25586d0a07edSAndrea Arcangeli * page_trans_huge_mapcount(), however we only use 25596d0a07edSAndrea Arcangeli * page_trans_huge_mapcount() in the copy-on-write faults where we 25606d0a07edSAndrea Arcangeli * need full accuracy to avoid breaking page pinning, because 25616d0a07edSAndrea Arcangeli * page_trans_huge_mapcount() is slower than page_mapcount(). 25626d0a07edSAndrea Arcangeli */ 25636d0a07edSAndrea Arcangeli int page_trans_huge_mapcount(struct page *page, int *total_mapcount) 25646d0a07edSAndrea Arcangeli { 25656d0a07edSAndrea Arcangeli int i, ret, _total_mapcount, mapcount; 25666d0a07edSAndrea Arcangeli 25676d0a07edSAndrea Arcangeli /* hugetlbfs shouldn't call it */ 25686d0a07edSAndrea Arcangeli VM_BUG_ON_PAGE(PageHuge(page), page); 25696d0a07edSAndrea Arcangeli 25706d0a07edSAndrea Arcangeli if (likely(!PageTransCompound(page))) { 25716d0a07edSAndrea Arcangeli mapcount = atomic_read(&page->_mapcount) + 1; 25726d0a07edSAndrea Arcangeli if (total_mapcount) 25736d0a07edSAndrea Arcangeli *total_mapcount = mapcount; 25746d0a07edSAndrea Arcangeli return mapcount; 25756d0a07edSAndrea Arcangeli } 25766d0a07edSAndrea Arcangeli 25776d0a07edSAndrea Arcangeli page = compound_head(page); 25786d0a07edSAndrea Arcangeli 25796d0a07edSAndrea Arcangeli _total_mapcount = ret = 0; 258065dfe3c3SMatthew Wilcox (Oracle) for (i = 0; i < thp_nr_pages(page); i++) { 25816d0a07edSAndrea Arcangeli mapcount = atomic_read(&page[i]._mapcount) + 1; 25826d0a07edSAndrea Arcangeli ret = max(ret, mapcount); 25836d0a07edSAndrea Arcangeli _total_mapcount += mapcount; 25846d0a07edSAndrea Arcangeli } 25856d0a07edSAndrea Arcangeli if (PageDoubleMap(page)) { 25866d0a07edSAndrea Arcangeli ret -= 1; 258765dfe3c3SMatthew Wilcox (Oracle) _total_mapcount -= thp_nr_pages(page); 25886d0a07edSAndrea Arcangeli } 25896d0a07edSAndrea Arcangeli mapcount = compound_mapcount(page); 25906d0a07edSAndrea Arcangeli ret += mapcount; 25916d0a07edSAndrea Arcangeli _total_mapcount += mapcount; 25926d0a07edSAndrea Arcangeli if (total_mapcount) 25936d0a07edSAndrea Arcangeli *total_mapcount = _total_mapcount; 25946d0a07edSAndrea Arcangeli return ret; 25956d0a07edSAndrea Arcangeli } 25966d0a07edSAndrea Arcangeli 2597b8f593cdSHuang Ying /* Racy check whether the huge page can be split */ 2598b8f593cdSHuang Ying bool can_split_huge_page(struct page *page, int *pextra_pins) 2599b8f593cdSHuang Ying { 2600b8f593cdSHuang Ying int extra_pins; 2601b8f593cdSHuang Ying 2602aa5dc07fSMatthew Wilcox /* Additional pins from page cache */ 2603b8f593cdSHuang Ying if (PageAnon(page)) 2604e2333dadSMatthew Wilcox (Oracle) extra_pins = PageSwapCache(page) ? thp_nr_pages(page) : 0; 2605b8f593cdSHuang Ying else 2606e2333dadSMatthew Wilcox (Oracle) extra_pins = thp_nr_pages(page); 2607b8f593cdSHuang Ying if (pextra_pins) 2608b8f593cdSHuang Ying *pextra_pins = extra_pins; 2609b8f593cdSHuang Ying return total_mapcount(page) == page_count(page) - extra_pins - 1; 2610b8f593cdSHuang Ying } 2611b8f593cdSHuang Ying 26126d0a07edSAndrea Arcangeli /* 2613e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2614e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2615e9b61f19SKirill A. Shutemov * 2616e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2617e9b61f19SKirill A. Shutemov * The huge page must be locked. 2618e9b61f19SKirill A. Shutemov * 2619e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2620e9b61f19SKirill A. Shutemov * 2621e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2622e9b61f19SKirill A. Shutemov * the hugepage. 2623e9b61f19SKirill A. Shutemov * 2624e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2625e9b61f19SKirill A. Shutemov * they are not mapped. 2626e9b61f19SKirill A. Shutemov * 2627e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2628e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2629e9b61f19SKirill A. Shutemov * us. 2630e9b61f19SKirill A. Shutemov */ 2631e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2632e9b61f19SKirill A. Shutemov { 2633e9b61f19SKirill A. Shutemov struct page *head = compound_head(page); 2634a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); 2635a8803e6cSWei Yang struct deferred_split *ds_queue = get_deferred_split_queue(head); 2636baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2637baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2638baa355fdSKirill A. Shutemov int count, mapcount, extra_pins, ret; 26390b9b6fffSKirill A. Shutemov unsigned long flags; 2640006d3ff2SHugh Dickins pgoff_t end; 2641e9b61f19SKirill A. Shutemov 2642cb829624SWei Yang VM_BUG_ON_PAGE(is_huge_zero_page(head), head); 2643a8803e6cSWei Yang VM_BUG_ON_PAGE(!PageLocked(head), head); 2644a8803e6cSWei Yang VM_BUG_ON_PAGE(!PageCompound(head), head); 2645e9b61f19SKirill A. Shutemov 2646a8803e6cSWei Yang if (PageWriteback(head)) 264759807685SHuang Ying return -EBUSY; 264859807685SHuang Ying 2649baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2650e9b61f19SKirill A. Shutemov /* 2651c1e8d7c6SMichel Lespinasse * The caller does not necessarily hold an mmap_lock that would 2652baa355fdSKirill A. Shutemov * prevent the anon_vma disappearing so we first we take a 2653baa355fdSKirill A. Shutemov * reference to it and then lock the anon_vma for write. This 2654baa355fdSKirill A. Shutemov * is similar to page_lock_anon_vma_read except the write lock 2655baa355fdSKirill A. Shutemov * is taken to serialise against parallel split or collapse 2656baa355fdSKirill A. Shutemov * operations. 2657e9b61f19SKirill A. Shutemov */ 2658e9b61f19SKirill A. Shutemov anon_vma = page_get_anon_vma(head); 2659e9b61f19SKirill A. Shutemov if (!anon_vma) { 2660e9b61f19SKirill A. Shutemov ret = -EBUSY; 2661e9b61f19SKirill A. Shutemov goto out; 2662e9b61f19SKirill A. Shutemov } 2663006d3ff2SHugh Dickins end = -1; 2664baa355fdSKirill A. Shutemov mapping = NULL; 2665e9b61f19SKirill A. Shutemov anon_vma_lock_write(anon_vma); 2666baa355fdSKirill A. Shutemov } else { 2667baa355fdSKirill A. Shutemov mapping = head->mapping; 2668baa355fdSKirill A. Shutemov 2669baa355fdSKirill A. Shutemov /* Truncated ? */ 2670baa355fdSKirill A. Shutemov if (!mapping) { 2671baa355fdSKirill A. Shutemov ret = -EBUSY; 2672baa355fdSKirill A. Shutemov goto out; 2673baa355fdSKirill A. Shutemov } 2674baa355fdSKirill A. Shutemov 2675baa355fdSKirill A. Shutemov anon_vma = NULL; 2676baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 2677006d3ff2SHugh Dickins 2678006d3ff2SHugh Dickins /* 2679006d3ff2SHugh Dickins *__split_huge_page() may need to trim off pages beyond EOF: 2680006d3ff2SHugh Dickins * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, 2681006d3ff2SHugh Dickins * which cannot be nested inside the page tree lock. So note 2682006d3ff2SHugh Dickins * end now: i_size itself may be changed at any moment, but 2683006d3ff2SHugh Dickins * head page lock is good enough to serialize the trimming. 2684006d3ff2SHugh Dickins */ 2685006d3ff2SHugh Dickins end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); 2686baa355fdSKirill A. Shutemov } 2687e9b61f19SKirill A. Shutemov 2688e9b61f19SKirill A. Shutemov /* 2689906f9cdfSHugh Dickins * Racy check if we can split the page, before unmap_page() will 2690e9b61f19SKirill A. Shutemov * split PMDs 2691e9b61f19SKirill A. Shutemov */ 2692b8f593cdSHuang Ying if (!can_split_huge_page(head, &extra_pins)) { 2693e9b61f19SKirill A. Shutemov ret = -EBUSY; 2694e9b61f19SKirill A. Shutemov goto out_unlock; 2695e9b61f19SKirill A. Shutemov } 2696e9b61f19SKirill A. Shutemov 2697906f9cdfSHugh Dickins unmap_page(head); 2698e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(compound_mapcount(head), head); 2699e9b61f19SKirill A. Shutemov 2700baa355fdSKirill A. Shutemov /* prevent PageLRU to go away from under us, and freeze lru stats */ 2701f4b7e272SAndrey Ryabinin spin_lock_irqsave(&pgdata->lru_lock, flags); 2702baa355fdSKirill A. Shutemov 2703baa355fdSKirill A. Shutemov if (mapping) { 2704aa5dc07fSMatthew Wilcox XA_STATE(xas, &mapping->i_pages, page_index(head)); 2705baa355fdSKirill A. Shutemov 2706baa355fdSKirill A. Shutemov /* 2707aa5dc07fSMatthew Wilcox * Check if the head page is present in page cache. 2708baa355fdSKirill A. Shutemov * We assume all tail are present too, if head is there. 2709baa355fdSKirill A. Shutemov */ 2710aa5dc07fSMatthew Wilcox xa_lock(&mapping->i_pages); 2711aa5dc07fSMatthew Wilcox if (xas_load(&xas) != head) 2712baa355fdSKirill A. Shutemov goto fail; 2713baa355fdSKirill A. Shutemov } 2714baa355fdSKirill A. Shutemov 27150139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 2716364c1eebSYang Shi spin_lock(&ds_queue->split_queue_lock); 2717e9b61f19SKirill A. Shutemov count = page_count(head); 2718e9b61f19SKirill A. Shutemov mapcount = total_mapcount(head); 2719baa355fdSKirill A. Shutemov if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { 27209a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(head))) { 2721364c1eebSYang Shi ds_queue->split_queue_len--; 27229a982250SKirill A. Shutemov list_del(page_deferred_list(head)); 27239a982250SKirill A. Shutemov } 2724afb97172SWei Yang spin_unlock(&ds_queue->split_queue_lock); 272506d3eff6SKirill A. Shutemov if (mapping) { 2726a8803e6cSWei Yang if (PageSwapBacked(head)) 2727b8eddff8SJohannes Weiner __dec_lruvec_page_state(head, NR_SHMEM_THPS); 272806d3eff6SKirill A. Shutemov else 2729b8eddff8SJohannes Weiner __dec_lruvec_page_state(head, NR_FILE_THPS); 273006d3eff6SKirill A. Shutemov } 273106d3eff6SKirill A. Shutemov 2732006d3ff2SHugh Dickins __split_huge_page(page, list, end, flags); 2733e9b61f19SKirill A. Shutemov ret = 0; 2734baa355fdSKirill A. Shutemov } else { 2735baa355fdSKirill A. Shutemov if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { 2736e9b61f19SKirill A. Shutemov pr_alert("total_mapcount: %u, page_count(): %u\n", 2737e9b61f19SKirill A. Shutemov mapcount, count); 2738e9b61f19SKirill A. Shutemov if (PageTail(page)) 2739e9b61f19SKirill A. Shutemov dump_page(head, NULL); 2740bd56086fSKirill A. Shutemov dump_page(page, "total_mapcount(head) > 0"); 2741e9b61f19SKirill A. Shutemov BUG(); 2742baa355fdSKirill A. Shutemov } 2743364c1eebSYang Shi spin_unlock(&ds_queue->split_queue_lock); 2744baa355fdSKirill A. Shutemov fail: if (mapping) 2745b93b0163SMatthew Wilcox xa_unlock(&mapping->i_pages); 2746f4b7e272SAndrey Ryabinin spin_unlock_irqrestore(&pgdata->lru_lock, flags); 27478cce5475SKirill A. Shutemov remap_page(head, thp_nr_pages(head)); 2748e9b61f19SKirill A. Shutemov ret = -EBUSY; 2749e9b61f19SKirill A. Shutemov } 2750e9b61f19SKirill A. Shutemov 2751e9b61f19SKirill A. Shutemov out_unlock: 2752baa355fdSKirill A. Shutemov if (anon_vma) { 2753e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 2754e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 2755baa355fdSKirill A. Shutemov } 2756baa355fdSKirill A. Shutemov if (mapping) 2757baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 2758e9b61f19SKirill A. Shutemov out: 2759e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 2760e9b61f19SKirill A. Shutemov return ret; 2761e9b61f19SKirill A. Shutemov } 27629a982250SKirill A. Shutemov 27639a982250SKirill A. Shutemov void free_transhuge_page(struct page *page) 27649a982250SKirill A. Shutemov { 276587eaceb3SYang Shi struct deferred_split *ds_queue = get_deferred_split_queue(page); 27669a982250SKirill A. Shutemov unsigned long flags; 27679a982250SKirill A. Shutemov 2768364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 27699a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(page))) { 2770364c1eebSYang Shi ds_queue->split_queue_len--; 27719a982250SKirill A. Shutemov list_del(page_deferred_list(page)); 27729a982250SKirill A. Shutemov } 2773364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 27749a982250SKirill A. Shutemov free_compound_page(page); 27759a982250SKirill A. Shutemov } 27769a982250SKirill A. Shutemov 27779a982250SKirill A. Shutemov void deferred_split_huge_page(struct page *page) 27789a982250SKirill A. Shutemov { 277987eaceb3SYang Shi struct deferred_split *ds_queue = get_deferred_split_queue(page); 278087eaceb3SYang Shi #ifdef CONFIG_MEMCG 278187eaceb3SYang Shi struct mem_cgroup *memcg = compound_head(page)->mem_cgroup; 278287eaceb3SYang Shi #endif 27839a982250SKirill A. Shutemov unsigned long flags; 27849a982250SKirill A. Shutemov 27859a982250SKirill A. Shutemov VM_BUG_ON_PAGE(!PageTransHuge(page), page); 27869a982250SKirill A. Shutemov 278787eaceb3SYang Shi /* 278887eaceb3SYang Shi * The try_to_unmap() in page reclaim path might reach here too, 278987eaceb3SYang Shi * this may cause a race condition to corrupt deferred split queue. 279087eaceb3SYang Shi * And, if page reclaim is already handling the same page, it is 279187eaceb3SYang Shi * unnecessary to handle it again in shrinker. 279287eaceb3SYang Shi * 279387eaceb3SYang Shi * Check PageSwapCache to determine if the page is being 279487eaceb3SYang Shi * handled by page reclaim since THP swap would add the page into 279587eaceb3SYang Shi * swap cache before calling try_to_unmap(). 279687eaceb3SYang Shi */ 279787eaceb3SYang Shi if (PageSwapCache(page)) 279887eaceb3SYang Shi return; 279987eaceb3SYang Shi 2800364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28019a982250SKirill A. Shutemov if (list_empty(page_deferred_list(page))) { 2802f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 2803364c1eebSYang Shi list_add_tail(page_deferred_list(page), &ds_queue->split_queue); 2804364c1eebSYang Shi ds_queue->split_queue_len++; 280587eaceb3SYang Shi #ifdef CONFIG_MEMCG 280687eaceb3SYang Shi if (memcg) 280787eaceb3SYang Shi memcg_set_shrinker_bit(memcg, page_to_nid(page), 280887eaceb3SYang Shi deferred_split_shrinker.id); 280987eaceb3SYang Shi #endif 28109a982250SKirill A. Shutemov } 2811364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28129a982250SKirill A. Shutemov } 28139a982250SKirill A. Shutemov 28149a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 28159a982250SKirill A. Shutemov struct shrink_control *sc) 28169a982250SKirill A. Shutemov { 2817a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2818364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 281987eaceb3SYang Shi 282087eaceb3SYang Shi #ifdef CONFIG_MEMCG 282187eaceb3SYang Shi if (sc->memcg) 282287eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 282387eaceb3SYang Shi #endif 2824364c1eebSYang Shi return READ_ONCE(ds_queue->split_queue_len); 28259a982250SKirill A. Shutemov } 28269a982250SKirill A. Shutemov 28279a982250SKirill A. Shutemov static unsigned long deferred_split_scan(struct shrinker *shrink, 28289a982250SKirill A. Shutemov struct shrink_control *sc) 28299a982250SKirill A. Shutemov { 2830a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2831364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 28329a982250SKirill A. Shutemov unsigned long flags; 28339a982250SKirill A. Shutemov LIST_HEAD(list), *pos, *next; 28349a982250SKirill A. Shutemov struct page *page; 28359a982250SKirill A. Shutemov int split = 0; 28369a982250SKirill A. Shutemov 283787eaceb3SYang Shi #ifdef CONFIG_MEMCG 283887eaceb3SYang Shi if (sc->memcg) 283987eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 284087eaceb3SYang Shi #endif 284187eaceb3SYang Shi 2842364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28439a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 2844364c1eebSYang Shi list_for_each_safe(pos, next, &ds_queue->split_queue) { 28459a982250SKirill A. Shutemov page = list_entry((void *)pos, struct page, mapping); 28469a982250SKirill A. Shutemov page = compound_head(page); 2847e3ae1953SKirill A. Shutemov if (get_page_unless_zero(page)) { 2848e3ae1953SKirill A. Shutemov list_move(page_deferred_list(page), &list); 2849e3ae1953SKirill A. Shutemov } else { 2850e3ae1953SKirill A. Shutemov /* We lost race with put_compound_page() */ 28519a982250SKirill A. Shutemov list_del_init(page_deferred_list(page)); 2852364c1eebSYang Shi ds_queue->split_queue_len--; 28539a982250SKirill A. Shutemov } 2854e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 2855e3ae1953SKirill A. Shutemov break; 28569a982250SKirill A. Shutemov } 2857364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28589a982250SKirill A. Shutemov 28599a982250SKirill A. Shutemov list_for_each_safe(pos, next, &list) { 28609a982250SKirill A. Shutemov page = list_entry((void *)pos, struct page, mapping); 2861fa41b900SKirill A. Shutemov if (!trylock_page(page)) 2862fa41b900SKirill A. Shutemov goto next; 28639a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 28649a982250SKirill A. Shutemov if (!split_huge_page(page)) 28659a982250SKirill A. Shutemov split++; 28669a982250SKirill A. Shutemov unlock_page(page); 2867fa41b900SKirill A. Shutemov next: 28689a982250SKirill A. Shutemov put_page(page); 28699a982250SKirill A. Shutemov } 28709a982250SKirill A. Shutemov 2871364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 2872364c1eebSYang Shi list_splice_tail(&list, &ds_queue->split_queue); 2873364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28749a982250SKirill A. Shutemov 2875cb8d68ecSKirill A. Shutemov /* 2876cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 2877cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 2878cb8d68ecSKirill A. Shutemov */ 2879364c1eebSYang Shi if (!split && list_empty(&ds_queue->split_queue)) 2880cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 2881cb8d68ecSKirill A. Shutemov return split; 28829a982250SKirill A. Shutemov } 28839a982250SKirill A. Shutemov 28849a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker = { 28859a982250SKirill A. Shutemov .count_objects = deferred_split_count, 28869a982250SKirill A. Shutemov .scan_objects = deferred_split_scan, 28879a982250SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 288887eaceb3SYang Shi .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | 288987eaceb3SYang Shi SHRINKER_NONSLAB, 28909a982250SKirill A. Shutemov }; 289149071d43SKirill A. Shutemov 289249071d43SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 289349071d43SKirill A. Shutemov static int split_huge_pages_set(void *data, u64 val) 289449071d43SKirill A. Shutemov { 289549071d43SKirill A. Shutemov struct zone *zone; 289649071d43SKirill A. Shutemov struct page *page; 289749071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 289849071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 289949071d43SKirill A. Shutemov 290049071d43SKirill A. Shutemov if (val != 1) 290149071d43SKirill A. Shutemov return -EINVAL; 290249071d43SKirill A. Shutemov 290349071d43SKirill A. Shutemov for_each_populated_zone(zone) { 290449071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 290549071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 290649071d43SKirill A. Shutemov if (!pfn_valid(pfn)) 290749071d43SKirill A. Shutemov continue; 290849071d43SKirill A. Shutemov 290949071d43SKirill A. Shutemov page = pfn_to_page(pfn); 291049071d43SKirill A. Shutemov if (!get_page_unless_zero(page)) 291149071d43SKirill A. Shutemov continue; 291249071d43SKirill A. Shutemov 291349071d43SKirill A. Shutemov if (zone != page_zone(page)) 291449071d43SKirill A. Shutemov goto next; 291549071d43SKirill A. Shutemov 2916baa355fdSKirill A. Shutemov if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) 291749071d43SKirill A. Shutemov goto next; 291849071d43SKirill A. Shutemov 291949071d43SKirill A. Shutemov total++; 292049071d43SKirill A. Shutemov lock_page(page); 292149071d43SKirill A. Shutemov if (!split_huge_page(page)) 292249071d43SKirill A. Shutemov split++; 292349071d43SKirill A. Shutemov unlock_page(page); 292449071d43SKirill A. Shutemov next: 292549071d43SKirill A. Shutemov put_page(page); 292649071d43SKirill A. Shutemov } 292749071d43SKirill A. Shutemov } 292849071d43SKirill A. Shutemov 2929145bdaa1SYang Shi pr_info("%lu of %lu THP split\n", split, total); 293049071d43SKirill A. Shutemov 293149071d43SKirill A. Shutemov return 0; 293249071d43SKirill A. Shutemov } 2933f1287869Szhong jiang DEFINE_DEBUGFS_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, 293449071d43SKirill A. Shutemov "%llu\n"); 293549071d43SKirill A. Shutemov 293649071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 293749071d43SKirill A. Shutemov { 2938d9f7979cSGreg Kroah-Hartman debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 293949071d43SKirill A. Shutemov &split_huge_pages_fops); 294049071d43SKirill A. Shutemov return 0; 294149071d43SKirill A. Shutemov } 294249071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 294349071d43SKirill A. Shutemov #endif 2944616b8371SZi Yan 2945616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 2946616b8371SZi Yan void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 2947616b8371SZi Yan struct page *page) 2948616b8371SZi Yan { 2949616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 2950616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 2951616b8371SZi Yan unsigned long address = pvmw->address; 2952616b8371SZi Yan pmd_t pmdval; 2953616b8371SZi Yan swp_entry_t entry; 2954ab6e3d09SNaoya Horiguchi pmd_t pmdswp; 2955616b8371SZi Yan 2956616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 2957616b8371SZi Yan return; 2958616b8371SZi Yan 2959616b8371SZi Yan flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); 29608a8683adSHuang Ying pmdval = pmdp_invalidate(vma, address, pvmw->pmd); 2961616b8371SZi Yan if (pmd_dirty(pmdval)) 2962616b8371SZi Yan set_page_dirty(page); 2963616b8371SZi Yan entry = make_migration_entry(page, pmd_write(pmdval)); 2964ab6e3d09SNaoya Horiguchi pmdswp = swp_entry_to_pmd(entry); 2965ab6e3d09SNaoya Horiguchi if (pmd_soft_dirty(pmdval)) 2966ab6e3d09SNaoya Horiguchi pmdswp = pmd_swp_mksoft_dirty(pmdswp); 2967ab6e3d09SNaoya Horiguchi set_pmd_at(mm, address, pvmw->pmd, pmdswp); 2968616b8371SZi Yan page_remove_rmap(page, true); 2969616b8371SZi Yan put_page(page); 2970616b8371SZi Yan } 2971616b8371SZi Yan 2972616b8371SZi Yan void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 2973616b8371SZi Yan { 2974616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 2975616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 2976616b8371SZi Yan unsigned long address = pvmw->address; 2977616b8371SZi Yan unsigned long mmun_start = address & HPAGE_PMD_MASK; 2978616b8371SZi Yan pmd_t pmde; 2979616b8371SZi Yan swp_entry_t entry; 2980616b8371SZi Yan 2981616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 2982616b8371SZi Yan return; 2983616b8371SZi Yan 2984616b8371SZi Yan entry = pmd_to_swp_entry(*pvmw->pmd); 2985616b8371SZi Yan get_page(new); 2986616b8371SZi Yan pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); 2987ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pvmw->pmd)) 2988ab6e3d09SNaoya Horiguchi pmde = pmd_mksoft_dirty(pmde); 2989616b8371SZi Yan if (is_write_migration_entry(entry)) 2990f55e1014SLinus Torvalds pmde = maybe_pmd_mkwrite(pmde, vma); 2991616b8371SZi Yan 2992616b8371SZi Yan flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); 2993e71769aeSNaoya Horiguchi if (PageAnon(new)) 2994616b8371SZi Yan page_add_anon_rmap(new, vma, mmun_start, true); 2995e71769aeSNaoya Horiguchi else 2996e71769aeSNaoya Horiguchi page_add_file_rmap(new, true); 2997616b8371SZi Yan set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); 2998e125fe40SKirill A. Shutemov if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) 2999616b8371SZi Yan mlock_vma_page(new); 3000616b8371SZi Yan update_mmu_cache_pmd(vma, address, pvmw->pmd); 3001616b8371SZi Yan } 3002616b8371SZi Yan #endif 3003