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> 10fa6c0231SZi Yan #include <linux/sched/mm.h> 11f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 126a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 1371e3aac0SAndrea Arcangeli #include <linux/highmem.h> 1471e3aac0SAndrea Arcangeli #include <linux/hugetlb.h> 1571e3aac0SAndrea Arcangeli #include <linux/mmu_notifier.h> 1671e3aac0SAndrea Arcangeli #include <linux/rmap.h> 1771e3aac0SAndrea Arcangeli #include <linux/swap.h> 1897ae1749SKirill A. Shutemov #include <linux/shrinker.h> 19ba76149fSAndrea Arcangeli #include <linux/mm_inline.h> 20e9b61f19SKirill A. Shutemov #include <linux/swapops.h> 21fb5c2029SMatthew Wilcox (Oracle) #include <linux/backing-dev.h> 224897c765SMatthew Wilcox #include <linux/dax.h> 23ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 24878aee7dSAndrea Arcangeli #include <linux/freezer.h> 25f25748e3SDan Williams #include <linux/pfn_t.h> 26a664b2d8SAndrea Arcangeli #include <linux/mman.h> 273565fce3SDan Williams #include <linux/memremap.h> 28325adeb5SRalf Baechle #include <linux/pagemap.h> 2949071d43SKirill A. Shutemov #include <linux/debugfs.h> 304daae3b4SMel Gorman #include <linux/migrate.h> 3143b5fbbdSSasha Levin #include <linux/hashtable.h> 326b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 3333c3fc71SVladimir Davydov #include <linux/page_idle.h> 34baa355fdSKirill A. Shutemov #include <linux/shmem_fs.h> 356b31d595SMichal Hocko #include <linux/oom.h> 3698fa15f3SAnshuman Khandual #include <linux/numa.h> 37f7da677bSVlastimil Babka #include <linux/page_owner.h> 38a1a3a2fcSHuang Ying #include <linux/sched/sysctl.h> 39467b171aSAneesh Kumar K.V #include <linux/memory-tiers.h> 4097ae1749SKirill A. Shutemov 4171e3aac0SAndrea Arcangeli #include <asm/tlb.h> 4271e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 4371e3aac0SAndrea Arcangeli #include "internal.h" 44014bb1deSNeilBrown #include "swap.h" 4571e3aac0SAndrea Arcangeli 46283fd6feSAnshuman Khandual #define CREATE_TRACE_POINTS 47283fd6feSAnshuman Khandual #include <trace/events/thp.h> 48283fd6feSAnshuman Khandual 49ba76149fSAndrea Arcangeli /* 50b14d595aSMichael DeGuzis * By default, transparent hugepage support is disabled in order to avoid 51b14d595aSMichael DeGuzis * risking an increased memory footprint for applications that are not 52b14d595aSMichael DeGuzis * guaranteed to benefit from it. When transparent hugepage support is 53b14d595aSMichael DeGuzis * enabled, it is for all mappings, and khugepaged scans all mappings. 548bfa3f9aSJianguo Wu * Defrag is invoked by khugepaged hugepage allocations and by page faults 558bfa3f9aSJianguo Wu * for all hugepage allocations. 56ba76149fSAndrea Arcangeli */ 5771e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 5813ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 59ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 6013ece886SAndrea Arcangeli #endif 6113ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 6213ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 6313ece886SAndrea Arcangeli #endif 64444eb2a4SMel Gorman (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| 6579da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 6679da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 67ba76149fSAndrea Arcangeli 6854d91729SQi Zheng static struct shrinker *deferred_split_shrinker; 6954d91729SQi Zheng static unsigned long deferred_split_count(struct shrinker *shrink, 7054d91729SQi Zheng struct shrink_control *sc); 7154d91729SQi Zheng static unsigned long deferred_split_scan(struct shrinker *shrink, 7254d91729SQi Zheng struct shrink_control *sc); 73f000565aSAndrea Arcangeli 7497ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 7556873f43SWang, Yalin struct page *huge_zero_page __read_mostly; 763b77e8c8SHugh Dickins unsigned long huge_zero_pfn __read_mostly = ~0UL; 774a6c1297SKirill A. Shutemov 78a7f4e6e4SZach O'Keefe bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, 79a7f4e6e4SZach O'Keefe bool smaps, bool in_pf, bool enforce_sysfs) 807635d9cbSMichal Hocko { 819fec5168SYang Shi if (!vma->vm_mm) /* vdso */ 82c0630669SYang Shi return false; 839fec5168SYang Shi 847da4e2cbSYang Shi /* 857da4e2cbSYang Shi * Explicitly disabled through madvise or prctl, or some 867da4e2cbSYang Shi * architectures may disable THP for some mappings, for 877da4e2cbSYang Shi * example, s390 kvm. 887da4e2cbSYang Shi * */ 897da4e2cbSYang Shi if ((vm_flags & VM_NOHUGEPAGE) || 907da4e2cbSYang Shi test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) 917da4e2cbSYang Shi return false; 927da4e2cbSYang Shi /* 937da4e2cbSYang Shi * If the hardware/firmware marked hugepage support disabled. 947da4e2cbSYang Shi */ 953c556d24SPeter Xu if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED)) 969fec5168SYang Shi return false; 979fec5168SYang Shi 987da4e2cbSYang Shi /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ 997da4e2cbSYang Shi if (vma_is_dax(vma)) 1007da4e2cbSYang Shi return in_pf; 1017da4e2cbSYang Shi 1027da4e2cbSYang Shi /* 1037a81751fSZach O'Keefe * khugepaged special VMA and hugetlb VMA. 1047da4e2cbSYang Shi * Must be checked after dax since some dax mappings may have 1057da4e2cbSYang Shi * VM_MIXEDMAP set. 1067da4e2cbSYang Shi */ 1077a81751fSZach O'Keefe if (!in_pf && !smaps && (vm_flags & VM_NO_KHUGEPAGED)) 1089fec5168SYang Shi return false; 1099fec5168SYang Shi 1107da4e2cbSYang Shi /* 1117da4e2cbSYang Shi * Check alignment for file vma and size for both file and anon vma. 1127da4e2cbSYang Shi * 1137da4e2cbSYang Shi * Skip the check for page fault. Huge fault does the check in fault 1147da4e2cbSYang Shi * handlers. And this check is not suitable for huge PUD fault. 1157da4e2cbSYang Shi */ 1167da4e2cbSYang Shi if (!in_pf && 1177da4e2cbSYang Shi !transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE))) 1189fec5168SYang Shi return false; 1199fec5168SYang Shi 1207da4e2cbSYang Shi /* 1217da4e2cbSYang Shi * Enabled via shmem mount options or sysfs settings. 1227da4e2cbSYang Shi * Must be done before hugepage flags check since shmem has its 1237da4e2cbSYang Shi * own flags. 1247da4e2cbSYang Shi */ 1257da4e2cbSYang Shi if (!in_pf && shmem_file(vma->vm_file)) 1262cf13384SDavid Stevens return shmem_is_huge(file_inode(vma->vm_file), vma->vm_pgoff, 1272cf13384SDavid Stevens !enforce_sysfs, vma->vm_mm, vm_flags); 1289fec5168SYang Shi 129a7f4e6e4SZach O'Keefe /* Enforce sysfs THP requirements as necessary */ 130a7f4e6e4SZach O'Keefe if (enforce_sysfs && 131a7f4e6e4SZach O'Keefe (!hugepage_flags_enabled() || (!(vm_flags & VM_HUGEPAGE) && 132a7f4e6e4SZach O'Keefe !hugepage_flags_always()))) 1339fec5168SYang Shi return false; 1349fec5168SYang Shi 1357a81751fSZach O'Keefe if (!vma_is_anonymous(vma)) { 1367a81751fSZach O'Keefe /* 1377a81751fSZach O'Keefe * Trust that ->huge_fault() handlers know what they are doing 1387a81751fSZach O'Keefe * in fault path. 1397a81751fSZach O'Keefe */ 1407a81751fSZach O'Keefe if (((in_pf || smaps)) && vma->vm_ops->huge_fault) 14178d12c19SYang Shi return true; 1427a81751fSZach O'Keefe /* Only regular file is valid in collapse path */ 1437a81751fSZach O'Keefe if (((!in_pf || smaps)) && file_thp_enabled(vma)) 1447a81751fSZach O'Keefe return true; 1457635d9cbSMichal Hocko return false; 1467a81751fSZach O'Keefe } 1479fec5168SYang Shi 1489fec5168SYang Shi if (vma_is_temporary_stack(vma)) 1499fec5168SYang Shi return false; 1509fec5168SYang Shi 1519fec5168SYang Shi /* 1529fec5168SYang Shi * THPeligible bit of smaps should show 1 for proper VMAs even 1539fec5168SYang Shi * though anon_vma is not initialized yet. 1547da4e2cbSYang Shi * 1557da4e2cbSYang Shi * Allow page fault since anon_vma may be not initialized until 1567da4e2cbSYang Shi * the first page fault. 1579fec5168SYang Shi */ 1589fec5168SYang Shi if (!vma->anon_vma) 1597da4e2cbSYang Shi return (smaps || in_pf); 1609fec5168SYang Shi 1619fec5168SYang Shi return true; 1627635d9cbSMichal Hocko } 1637635d9cbSMichal Hocko 164aaa9705bSMiaohe Lin static bool get_huge_zero_page(void) 16597ae1749SKirill A. Shutemov { 16697ae1749SKirill A. Shutemov struct page *zero_page; 16797ae1749SKirill A. Shutemov retry: 16897ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 169aaa9705bSMiaohe Lin return true; 17097ae1749SKirill A. Shutemov 17197ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 17297ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 173d8a8e1f0SKirill A. Shutemov if (!zero_page) { 174d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 175aaa9705bSMiaohe Lin return false; 176d8a8e1f0SKirill A. Shutemov } 17797ae1749SKirill A. Shutemov preempt_disable(); 1785918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 17997ae1749SKirill A. Shutemov preempt_enable(); 1805ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 18197ae1749SKirill A. Shutemov goto retry; 18297ae1749SKirill A. Shutemov } 1833b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); 18497ae1749SKirill A. Shutemov 18597ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 18697ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 18797ae1749SKirill A. Shutemov preempt_enable(); 188f4981502SLiu Shixin count_vm_event(THP_ZERO_PAGE_ALLOC); 189aaa9705bSMiaohe Lin return true; 19097ae1749SKirill A. Shutemov } 19197ae1749SKirill A. Shutemov 1926fcb52a5SAaron Lu static void put_huge_zero_page(void) 19397ae1749SKirill A. Shutemov { 19497ae1749SKirill A. Shutemov /* 19597ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 19697ae1749SKirill A. Shutemov * last reference. 19797ae1749SKirill A. Shutemov */ 19897ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 19997ae1749SKirill A. Shutemov } 20097ae1749SKirill A. Shutemov 2016fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 2026fcb52a5SAaron Lu { 2036fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2046fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 2056fcb52a5SAaron Lu 2066fcb52a5SAaron Lu if (!get_huge_zero_page()) 2076fcb52a5SAaron Lu return NULL; 2086fcb52a5SAaron Lu 2096fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2106fcb52a5SAaron Lu put_huge_zero_page(); 2116fcb52a5SAaron Lu 2126fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 2136fcb52a5SAaron Lu } 2146fcb52a5SAaron Lu 2156fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 2166fcb52a5SAaron Lu { 2176fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2186fcb52a5SAaron Lu put_huge_zero_page(); 2196fcb52a5SAaron Lu } 2206fcb52a5SAaron Lu 22148896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 22297ae1749SKirill A. Shutemov struct shrink_control *sc) 22397ae1749SKirill A. Shutemov { 22497ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 22597ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 22648896466SGlauber Costa } 22797ae1749SKirill A. Shutemov 22848896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 22948896466SGlauber Costa struct shrink_control *sc) 23048896466SGlauber Costa { 23197ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2325918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2335918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2343b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, ~0UL); 2355ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 23648896466SGlauber Costa return HPAGE_PMD_NR; 23797ae1749SKirill A. Shutemov } 23897ae1749SKirill A. Shutemov 23997ae1749SKirill A. Shutemov return 0; 24097ae1749SKirill A. Shutemov } 24197ae1749SKirill A. Shutemov 24254d91729SQi Zheng static struct shrinker *huge_zero_page_shrinker; 24397ae1749SKirill A. Shutemov 24471e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 24571e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 24671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 24771e3aac0SAndrea Arcangeli { 248bfb0ffebSJoe Perches const char *output; 249bfb0ffebSJoe Perches 250444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 251bfb0ffebSJoe Perches output = "[always] madvise never"; 252bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 253bfb0ffebSJoe Perches &transparent_hugepage_flags)) 254bfb0ffebSJoe Perches output = "always [madvise] never"; 255444eb2a4SMel Gorman else 256bfb0ffebSJoe Perches output = "always madvise [never]"; 257bfb0ffebSJoe Perches 258bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 25971e3aac0SAndrea Arcangeli } 260444eb2a4SMel Gorman 26171e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 26271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 26371e3aac0SAndrea Arcangeli const char *buf, size_t count) 26471e3aac0SAndrea Arcangeli { 26521440d7eSDavid Rientjes ssize_t ret = count; 266ba76149fSAndrea Arcangeli 267f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 26821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 26921440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 270f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 27121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 27221440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 273f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 27421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 27521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 27621440d7eSDavid Rientjes } else 27721440d7eSDavid Rientjes ret = -EINVAL; 278ba76149fSAndrea Arcangeli 279ba76149fSAndrea Arcangeli if (ret > 0) { 280b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 281ba76149fSAndrea Arcangeli if (err) 282ba76149fSAndrea Arcangeli ret = err; 283ba76149fSAndrea Arcangeli } 284ba76149fSAndrea Arcangeli return ret; 28571e3aac0SAndrea Arcangeli } 28637139bb0SMiaohe Lin 28737139bb0SMiaohe Lin static struct kobj_attribute enabled_attr = __ATTR_RW(enabled); 28871e3aac0SAndrea Arcangeli 289b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 29071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 29171e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 29271e3aac0SAndrea Arcangeli { 293bfb0ffebSJoe Perches return sysfs_emit(buf, "%d\n", 294e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 29571e3aac0SAndrea Arcangeli } 296e27e6151SBen Hutchings 297b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 29871e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 29971e3aac0SAndrea Arcangeli const char *buf, size_t count, 30071e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 30171e3aac0SAndrea Arcangeli { 302e27e6151SBen Hutchings unsigned long value; 303e27e6151SBen Hutchings int ret; 304e27e6151SBen Hutchings 305e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 306e27e6151SBen Hutchings if (ret < 0) 307e27e6151SBen Hutchings return ret; 308e27e6151SBen Hutchings if (value > 1) 30971e3aac0SAndrea Arcangeli return -EINVAL; 31071e3aac0SAndrea Arcangeli 311e27e6151SBen Hutchings if (value) 312e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 313e27e6151SBen Hutchings else 314e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 315e27e6151SBen Hutchings 31671e3aac0SAndrea Arcangeli return count; 31771e3aac0SAndrea Arcangeli } 31871e3aac0SAndrea Arcangeli 31971e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 32071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 32171e3aac0SAndrea Arcangeli { 322bfb0ffebSJoe Perches const char *output; 323bfb0ffebSJoe Perches 324bfb0ffebSJoe Perches if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, 325bfb0ffebSJoe Perches &transparent_hugepage_flags)) 326bfb0ffebSJoe Perches output = "[always] defer defer+madvise madvise never"; 327bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, 328bfb0ffebSJoe Perches &transparent_hugepage_flags)) 329bfb0ffebSJoe Perches output = "always [defer] defer+madvise madvise never"; 330bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, 331bfb0ffebSJoe Perches &transparent_hugepage_flags)) 332bfb0ffebSJoe Perches output = "always defer [defer+madvise] madvise never"; 333bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, 334bfb0ffebSJoe Perches &transparent_hugepage_flags)) 335bfb0ffebSJoe Perches output = "always defer defer+madvise [madvise] never"; 336bfb0ffebSJoe Perches else 337bfb0ffebSJoe Perches output = "always defer defer+madvise madvise [never]"; 338bfb0ffebSJoe Perches 339bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 34071e3aac0SAndrea Arcangeli } 34121440d7eSDavid Rientjes 34271e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 34371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 34471e3aac0SAndrea Arcangeli const char *buf, size_t count) 34571e3aac0SAndrea Arcangeli { 346f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 34721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 34821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 34921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 35021440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 351f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer+madvise")) { 35221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 35321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 35421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 35521440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 356f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer")) { 3574fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 3584fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 3594fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 3604fad7fb6SDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 361f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 36221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 36321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 36421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 36521440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 366f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 36721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 36821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 36921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 37021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 37121440d7eSDavid Rientjes } else 37221440d7eSDavid Rientjes return -EINVAL; 37321440d7eSDavid Rientjes 37421440d7eSDavid Rientjes return count; 37571e3aac0SAndrea Arcangeli } 37637139bb0SMiaohe Lin static struct kobj_attribute defrag_attr = __ATTR_RW(defrag); 37771e3aac0SAndrea Arcangeli 37879da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 37979da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 38079da5407SKirill A. Shutemov { 381b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 38279da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 38379da5407SKirill A. Shutemov } 38479da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 38579da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 38679da5407SKirill A. Shutemov { 387b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 38879da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 38979da5407SKirill A. Shutemov } 39037139bb0SMiaohe Lin static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page); 39149920d28SHugh Dickins 39249920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 39349920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 39449920d28SHugh Dickins { 395ae7a927dSJoe Perches return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); 39649920d28SHugh Dickins } 39749920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 39849920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 39949920d28SHugh Dickins 40071e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 40171e3aac0SAndrea Arcangeli &enabled_attr.attr, 40271e3aac0SAndrea Arcangeli &defrag_attr.attr, 40379da5407SKirill A. Shutemov &use_zero_page_attr.attr, 40449920d28SHugh Dickins &hpage_pmd_size_attr.attr, 405396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_SHMEM 4065a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 4075a6e75f8SKirill A. Shutemov #endif 40871e3aac0SAndrea Arcangeli NULL, 40971e3aac0SAndrea Arcangeli }; 41071e3aac0SAndrea Arcangeli 4118aa95a21SArvind Yadav static const struct attribute_group hugepage_attr_group = { 41271e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 413ba76149fSAndrea Arcangeli }; 414ba76149fSAndrea Arcangeli 415569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 416569e5590SShaohua Li { 417569e5590SShaohua Li int err; 418569e5590SShaohua Li 419569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 420569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 421ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 422569e5590SShaohua Li return -ENOMEM; 423569e5590SShaohua Li } 424569e5590SShaohua Li 425569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 426569e5590SShaohua Li if (err) { 427ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 428569e5590SShaohua Li goto delete_obj; 429569e5590SShaohua Li } 430569e5590SShaohua Li 431569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 432569e5590SShaohua Li if (err) { 433ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 434569e5590SShaohua Li goto remove_hp_group; 435569e5590SShaohua Li } 436569e5590SShaohua Li 437569e5590SShaohua Li return 0; 438569e5590SShaohua Li 439569e5590SShaohua Li remove_hp_group: 440569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 441569e5590SShaohua Li delete_obj: 442569e5590SShaohua Li kobject_put(*hugepage_kobj); 443569e5590SShaohua Li return err; 444569e5590SShaohua Li } 445569e5590SShaohua Li 446569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 447569e5590SShaohua Li { 448569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 449569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 450569e5590SShaohua Li kobject_put(hugepage_kobj); 451569e5590SShaohua Li } 452569e5590SShaohua Li #else 453569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 454569e5590SShaohua Li { 455569e5590SShaohua Li return 0; 456569e5590SShaohua Li } 457569e5590SShaohua Li 458569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 459569e5590SShaohua Li { 460569e5590SShaohua Li } 46171e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 46271e3aac0SAndrea Arcangeli 46354d91729SQi Zheng static int __init thp_shrinker_init(void) 46454d91729SQi Zheng { 46554d91729SQi Zheng huge_zero_page_shrinker = shrinker_alloc(0, "thp-zero"); 46654d91729SQi Zheng if (!huge_zero_page_shrinker) 46754d91729SQi Zheng return -ENOMEM; 46854d91729SQi Zheng 46954d91729SQi Zheng deferred_split_shrinker = shrinker_alloc(SHRINKER_NUMA_AWARE | 47054d91729SQi Zheng SHRINKER_MEMCG_AWARE | 47154d91729SQi Zheng SHRINKER_NONSLAB, 47254d91729SQi Zheng "thp-deferred_split"); 47354d91729SQi Zheng if (!deferred_split_shrinker) { 47454d91729SQi Zheng shrinker_free(huge_zero_page_shrinker); 47554d91729SQi Zheng return -ENOMEM; 47654d91729SQi Zheng } 47754d91729SQi Zheng 47854d91729SQi Zheng huge_zero_page_shrinker->count_objects = shrink_huge_zero_page_count; 47954d91729SQi Zheng huge_zero_page_shrinker->scan_objects = shrink_huge_zero_page_scan; 48054d91729SQi Zheng shrinker_register(huge_zero_page_shrinker); 48154d91729SQi Zheng 48254d91729SQi Zheng deferred_split_shrinker->count_objects = deferred_split_count; 48354d91729SQi Zheng deferred_split_shrinker->scan_objects = deferred_split_scan; 48454d91729SQi Zheng shrinker_register(deferred_split_shrinker); 48554d91729SQi Zheng 48654d91729SQi Zheng return 0; 48754d91729SQi Zheng } 48854d91729SQi Zheng 48954d91729SQi Zheng static void __init thp_shrinker_exit(void) 49054d91729SQi Zheng { 49154d91729SQi Zheng shrinker_free(huge_zero_page_shrinker); 49254d91729SQi Zheng shrinker_free(deferred_split_shrinker); 49354d91729SQi Zheng } 49454d91729SQi Zheng 49571e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 49671e3aac0SAndrea Arcangeli { 49771e3aac0SAndrea Arcangeli int err; 498569e5590SShaohua Li struct kobject *hugepage_kobj; 49971e3aac0SAndrea Arcangeli 5004b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 5013c556d24SPeter Xu transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED; 502569e5590SShaohua Li return -EINVAL; 5034b7167b9SAndrea Arcangeli } 5044b7167b9SAndrea Arcangeli 505ff20c2e0SKirill A. Shutemov /* 506ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 507ff20c2e0SKirill A. Shutemov */ 50823baf831SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER > MAX_ORDER); 509ff20c2e0SKirill A. Shutemov /* 510ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 511ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 512ff20c2e0SKirill A. Shutemov */ 513ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 514ff20c2e0SKirill A. Shutemov 515569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 516569e5590SShaohua Li if (err) 51765ebb64fSKirill A. Shutemov goto err_sysfs; 518ba76149fSAndrea Arcangeli 519b46e756fSKirill A. Shutemov err = khugepaged_init(); 520ba76149fSAndrea Arcangeli if (err) 52165ebb64fSKirill A. Shutemov goto err_slab; 522ba76149fSAndrea Arcangeli 52354d91729SQi Zheng err = thp_shrinker_init(); 52465ebb64fSKirill A. Shutemov if (err) 52554d91729SQi Zheng goto err_shrinker; 52697ae1749SKirill A. Shutemov 52797562cd2SRik van Riel /* 52897562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 52997562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 53097562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 53197562cd2SRik van Riel */ 532ca79b0c2SArun KS if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { 53397562cd2SRik van Riel transparent_hugepage_flags = 0; 53479553da2SKirill A. Shutemov return 0; 53579553da2SKirill A. Shutemov } 53697562cd2SRik van Riel 53779553da2SKirill A. Shutemov err = start_stop_khugepaged(); 53865ebb64fSKirill A. Shutemov if (err) 53965ebb64fSKirill A. Shutemov goto err_khugepaged; 540ba76149fSAndrea Arcangeli 541569e5590SShaohua Li return 0; 54265ebb64fSKirill A. Shutemov err_khugepaged: 54354d91729SQi Zheng thp_shrinker_exit(); 54454d91729SQi Zheng err_shrinker: 545b46e756fSKirill A. Shutemov khugepaged_destroy(); 54665ebb64fSKirill A. Shutemov err_slab: 547569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 54865ebb64fSKirill A. Shutemov err_sysfs: 549ba76149fSAndrea Arcangeli return err; 55071e3aac0SAndrea Arcangeli } 551a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 55271e3aac0SAndrea Arcangeli 55371e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 55471e3aac0SAndrea Arcangeli { 55571e3aac0SAndrea Arcangeli int ret = 0; 55671e3aac0SAndrea Arcangeli if (!str) 55771e3aac0SAndrea Arcangeli goto out; 55871e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 55971e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 56071e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56171e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 56271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56371e3aac0SAndrea Arcangeli ret = 1; 56471e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 56571e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 56671e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56771e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 56871e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56971e3aac0SAndrea Arcangeli ret = 1; 57071e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 57171e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 57271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 57371e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 57471e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 57571e3aac0SAndrea Arcangeli ret = 1; 57671e3aac0SAndrea Arcangeli } 57771e3aac0SAndrea Arcangeli out: 57871e3aac0SAndrea Arcangeli if (!ret) 579ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 58071e3aac0SAndrea Arcangeli return ret; 58171e3aac0SAndrea Arcangeli } 58271e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 58371e3aac0SAndrea Arcangeli 584f55e1014SLinus Torvalds pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 58571e3aac0SAndrea Arcangeli { 586f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 587161e393cSRick Edgecombe pmd = pmd_mkwrite(pmd, vma); 58871e3aac0SAndrea Arcangeli return pmd; 58971e3aac0SAndrea Arcangeli } 59071e3aac0SAndrea Arcangeli 59187eaceb3SYang Shi #ifdef CONFIG_MEMCG 592f8baa6beSMatthew Wilcox (Oracle) static inline 593f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *get_deferred_split_queue(struct folio *folio) 5949a982250SKirill A. Shutemov { 595f8baa6beSMatthew Wilcox (Oracle) struct mem_cgroup *memcg = folio_memcg(folio); 596f8baa6beSMatthew Wilcox (Oracle) struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); 59787eaceb3SYang Shi 59887eaceb3SYang Shi if (memcg) 59987eaceb3SYang Shi return &memcg->deferred_split_queue; 60087eaceb3SYang Shi else 60187eaceb3SYang Shi return &pgdat->deferred_split_queue; 6029a982250SKirill A. Shutemov } 60387eaceb3SYang Shi #else 604f8baa6beSMatthew Wilcox (Oracle) static inline 605f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *get_deferred_split_queue(struct folio *folio) 60687eaceb3SYang Shi { 607f8baa6beSMatthew Wilcox (Oracle) struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); 60887eaceb3SYang Shi 60987eaceb3SYang Shi return &pgdat->deferred_split_queue; 61087eaceb3SYang Shi } 61187eaceb3SYang Shi #endif 6129a982250SKirill A. Shutemov 613da6e7bf3SMatthew Wilcox (Oracle) void folio_prep_large_rmappable(struct folio *folio) 6149a982250SKirill A. Shutemov { 6158991de90SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); 6168991de90SMatthew Wilcox (Oracle) INIT_LIST_HEAD(&folio->_deferred_list); 617de53c05fSMatthew Wilcox (Oracle) folio_set_large_rmappable(folio); 6189a982250SKirill A. Shutemov } 6199a982250SKirill A. Shutemov 620a644b0abSMatthew Wilcox (Oracle) static inline bool is_transparent_hugepage(struct folio *folio) 621005ba37cSSean Christopherson { 622a644b0abSMatthew Wilcox (Oracle) if (!folio_test_large(folio)) 623fa1f68ccSZou Wei return false; 624005ba37cSSean Christopherson 625f04029f3SMatthew Wilcox (Oracle) return is_huge_zero_page(&folio->page) || 626de53c05fSMatthew Wilcox (Oracle) folio_test_large_rmappable(folio); 627005ba37cSSean Christopherson } 628005ba37cSSean Christopherson 62997d3d0f9SKirill A. Shutemov static unsigned long __thp_get_unmapped_area(struct file *filp, 63097d3d0f9SKirill A. Shutemov unsigned long addr, unsigned long len, 63174d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 63274d2fad1SToshi Kani { 63374d2fad1SToshi Kani loff_t off_end = off + len; 63474d2fad1SToshi Kani loff_t off_align = round_up(off, size); 63597d3d0f9SKirill A. Shutemov unsigned long len_pad, ret; 63674d2fad1SToshi Kani 63774d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 63874d2fad1SToshi Kani return 0; 63974d2fad1SToshi Kani 64074d2fad1SToshi Kani len_pad = len + size; 64174d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 64274d2fad1SToshi Kani return 0; 64374d2fad1SToshi Kani 64497d3d0f9SKirill A. Shutemov ret = current->mm->get_unmapped_area(filp, addr, len_pad, 64574d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 64697d3d0f9SKirill A. Shutemov 64797d3d0f9SKirill A. Shutemov /* 64897d3d0f9SKirill A. Shutemov * The failure might be due to length padding. The caller will retry 64997d3d0f9SKirill A. Shutemov * without the padding. 65097d3d0f9SKirill A. Shutemov */ 65197d3d0f9SKirill A. Shutemov if (IS_ERR_VALUE(ret)) 65274d2fad1SToshi Kani return 0; 65374d2fad1SToshi Kani 65497d3d0f9SKirill A. Shutemov /* 65597d3d0f9SKirill A. Shutemov * Do not try to align to THP boundary if allocation at the address 65697d3d0f9SKirill A. Shutemov * hint succeeds. 65797d3d0f9SKirill A. Shutemov */ 65897d3d0f9SKirill A. Shutemov if (ret == addr) 65974d2fad1SToshi Kani return addr; 66097d3d0f9SKirill A. Shutemov 66197d3d0f9SKirill A. Shutemov ret += (off - ret) & (size - 1); 66297d3d0f9SKirill A. Shutemov return ret; 66374d2fad1SToshi Kani } 66474d2fad1SToshi Kani 66574d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 66674d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 66774d2fad1SToshi Kani { 66897d3d0f9SKirill A. Shutemov unsigned long ret; 66974d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 67074d2fad1SToshi Kani 67197d3d0f9SKirill A. Shutemov ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); 67297d3d0f9SKirill A. Shutemov if (ret) 67397d3d0f9SKirill A. Shutemov return ret; 6741854bc6eSWilliam Kucharski 67574d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 67674d2fad1SToshi Kani } 67774d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 67874d2fad1SToshi Kani 6792b740303SSouptick Joarder static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, 6802b740303SSouptick Joarder struct page *page, gfp_t gfp) 68171e3aac0SAndrea Arcangeli { 68282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 683cfe3236dSKefeng Wang struct folio *folio = page_folio(page); 68471e3aac0SAndrea Arcangeli pgtable_t pgtable; 68582b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 6862b740303SSouptick Joarder vm_fault_t ret = 0; 68771e3aac0SAndrea Arcangeli 688cfe3236dSKefeng Wang VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 68900501b53SJohannes Weiner 690cfe3236dSKefeng Wang if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) { 691cfe3236dSKefeng Wang folio_put(folio); 6926b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 69385b9f46eSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK_CHARGE); 6946b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 6956b251fc9SAndrea Arcangeli } 696cfe3236dSKefeng Wang folio_throttle_swaprate(folio, gfp); 69771e3aac0SAndrea Arcangeli 6984cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 69900501b53SJohannes Weiner if (unlikely(!pgtable)) { 7006b31d595SMichal Hocko ret = VM_FAULT_OOM; 7016b31d595SMichal Hocko goto release; 70200501b53SJohannes Weiner } 70300501b53SJohannes Weiner 704c79b57e4SHuang Ying clear_huge_page(page, vmf->address, HPAGE_PMD_NR); 70552f37629SMinchan Kim /* 706cfe3236dSKefeng Wang * The memory barrier inside __folio_mark_uptodate makes sure that 70752f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 70852f37629SMinchan Kim * write. 70952f37629SMinchan Kim */ 710cfe3236dSKefeng Wang __folio_mark_uptodate(folio); 71171e3aac0SAndrea Arcangeli 71282b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 71382b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 7146b31d595SMichal Hocko goto unlock_release; 71571e3aac0SAndrea Arcangeli } else { 71671e3aac0SAndrea Arcangeli pmd_t entry; 7176b251fc9SAndrea Arcangeli 7186b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 7196b31d595SMichal Hocko if (ret) 7206b31d595SMichal Hocko goto unlock_release; 7216b31d595SMichal Hocko 7226b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 7236b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 72482b0f8c3SJan Kara spin_unlock(vmf->ptl); 725cfe3236dSKefeng Wang folio_put(folio); 726bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 7278fd5eda4SMiaohe Lin ret = handle_userfault(vmf, VM_UFFD_MISSING); 7288fd5eda4SMiaohe Lin VM_BUG_ON(ret & VM_FAULT_FALLBACK); 7298fd5eda4SMiaohe Lin return ret; 7306b251fc9SAndrea Arcangeli } 7316b251fc9SAndrea Arcangeli 7323122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 733f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 734cfe3236dSKefeng Wang folio_add_new_anon_rmap(folio, vma, haddr); 735cfe3236dSKefeng Wang folio_add_lru_vma(folio, vma); 73682b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 73782b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 738fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 739bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 740c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 74182b0f8c3SJan Kara spin_unlock(vmf->ptl); 7426b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 7439d82c694SJohannes Weiner count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); 74471e3aac0SAndrea Arcangeli } 74571e3aac0SAndrea Arcangeli 746aa2e878eSDavid Rientjes return 0; 7476b31d595SMichal Hocko unlock_release: 7486b31d595SMichal Hocko spin_unlock(vmf->ptl); 7496b31d595SMichal Hocko release: 7506b31d595SMichal Hocko if (pgtable) 7516b31d595SMichal Hocko pte_free(vma->vm_mm, pgtable); 752cfe3236dSKefeng Wang folio_put(folio); 7536b31d595SMichal Hocko return ret; 7546b31d595SMichal Hocko 75571e3aac0SAndrea Arcangeli } 75671e3aac0SAndrea Arcangeli 757444eb2a4SMel Gorman /* 75821440d7eSDavid Rientjes * always: directly stall for all thp allocations 75921440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 76021440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 76121440d7eSDavid Rientjes * fail if not immediately available 76221440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 76321440d7eSDavid Rientjes * available 76421440d7eSDavid Rientjes * never: never stall for any thp allocation 765444eb2a4SMel Gorman */ 766164cc4feSRik van Riel gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) 7670bbbc0b3SAndrea Arcangeli { 768164cc4feSRik van Riel const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); 76989c83fb5SMichal Hocko 770ac79f78dSDavid Rientjes /* Always do synchronous compaction */ 77121440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 772a8282608SAndrea Arcangeli return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 773ac79f78dSDavid Rientjes 774ac79f78dSDavid Rientjes /* Kick kcompactd and fail quickly */ 77521440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 77619deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 777ac79f78dSDavid Rientjes 778ac79f78dSDavid Rientjes /* Synchronous compaction if madvised, otherwise kick kcompactd */ 77921440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 78019deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 78119deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 782ac79f78dSDavid Rientjes __GFP_KSWAPD_RECLAIM); 783ac79f78dSDavid Rientjes 784ac79f78dSDavid Rientjes /* Only do synchronous compaction if madvised */ 78521440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 78619deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 78719deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); 788ac79f78dSDavid Rientjes 78919deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT; 790444eb2a4SMel Gorman } 791444eb2a4SMel Gorman 792c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 7932efeb8daSMiaohe Lin static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 79497ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 7955918d10aSKirill A. Shutemov struct page *zero_page) 796fc9fe822SKirill A. Shutemov { 797fc9fe822SKirill A. Shutemov pmd_t entry; 7987c414164SAndrew Morton if (!pmd_none(*pmd)) 7992efeb8daSMiaohe Lin return; 8005918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 801fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 8026b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 803fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 804c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 805fc9fe822SKirill A. Shutemov } 806fc9fe822SKirill A. Shutemov 8072b740303SSouptick Joarder vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) 80871e3aac0SAndrea Arcangeli { 80982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 810077fcf11SAneesh Kumar K.V gfp_t gfp; 811cb196ee1SMatthew Wilcox (Oracle) struct folio *folio; 81282b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 81371e3aac0SAndrea Arcangeli 81443675e6fSYang Shi if (!transhuge_vma_suitable(vma, haddr)) 815c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 81671e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 81771e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 8184fa6893fSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 819d2081b2bSYang Shi 82082b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 821bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 82279da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 82380371957SKirill A. Shutemov pgtable_t pgtable; 8245918d10aSKirill A. Shutemov struct page *zero_page; 8252b740303SSouptick Joarder vm_fault_t ret; 8264cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 82780371957SKirill A. Shutemov if (unlikely(!pgtable)) 82880371957SKirill A. Shutemov return VM_FAULT_OOM; 8296fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 8305918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 831bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 83297ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 833c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 83497ae1749SKirill A. Shutemov } 83582b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 8366b251fc9SAndrea Arcangeli ret = 0; 83782b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 8386b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 8396b31d595SMichal Hocko if (ret) { 8406b31d595SMichal Hocko spin_unlock(vmf->ptl); 841bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 8426b31d595SMichal Hocko } else if (userfaultfd_missing(vma)) { 84382b0f8c3SJan Kara spin_unlock(vmf->ptl); 844bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 84582b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 8466b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 8476b251fc9SAndrea Arcangeli } else { 848bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 84982b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 850fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 85182b0f8c3SJan Kara spin_unlock(vmf->ptl); 8526b251fc9SAndrea Arcangeli } 853bfe8cc1dSGerald Schaefer } else { 85482b0f8c3SJan Kara spin_unlock(vmf->ptl); 855bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 856bfe8cc1dSGerald Schaefer } 8576b251fc9SAndrea Arcangeli return ret; 85880371957SKirill A. Shutemov } 859164cc4feSRik van Riel gfp = vma_thp_gfp_mask(vma); 860cb196ee1SMatthew Wilcox (Oracle) folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); 861cb196ee1SMatthew Wilcox (Oracle) if (unlikely(!folio)) { 86281ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 863c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 86481ab4201SAndi Kleen } 865cb196ee1SMatthew Wilcox (Oracle) return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); 86671e3aac0SAndrea Arcangeli } 86771e3aac0SAndrea Arcangeli 868ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 8693b6521f5SOliver O'Halloran pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, 8703b6521f5SOliver O'Halloran pgtable_t pgtable) 8715cad465dSMatthew Wilcox { 8725cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 8735cad465dSMatthew Wilcox pmd_t entry; 8745cad465dSMatthew Wilcox spinlock_t *ptl; 8755cad465dSMatthew Wilcox 8765cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 877c6f3c5eeSAneesh Kumar K.V if (!pmd_none(*pmd)) { 878c6f3c5eeSAneesh Kumar K.V if (write) { 879c6f3c5eeSAneesh Kumar K.V if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { 880c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); 881c6f3c5eeSAneesh Kumar K.V goto out_unlock; 882c6f3c5eeSAneesh Kumar K.V } 883c6f3c5eeSAneesh Kumar K.V entry = pmd_mkyoung(*pmd); 884c6f3c5eeSAneesh Kumar K.V entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 885c6f3c5eeSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) 886c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 887c6f3c5eeSAneesh Kumar K.V } 888c6f3c5eeSAneesh Kumar K.V 889c6f3c5eeSAneesh Kumar K.V goto out_unlock; 890c6f3c5eeSAneesh Kumar K.V } 891c6f3c5eeSAneesh Kumar K.V 892f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 893f25748e3SDan Williams if (pfn_t_devmap(pfn)) 894f25748e3SDan Williams entry = pmd_mkdevmap(entry); 8955cad465dSMatthew Wilcox if (write) { 896f55e1014SLinus Torvalds entry = pmd_mkyoung(pmd_mkdirty(entry)); 897f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(entry, vma); 8985cad465dSMatthew Wilcox } 8993b6521f5SOliver O'Halloran 9003b6521f5SOliver O'Halloran if (pgtable) { 9013b6521f5SOliver O'Halloran pgtable_trans_huge_deposit(mm, pmd, pgtable); 902c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 903c6f3c5eeSAneesh Kumar K.V pgtable = NULL; 9043b6521f5SOliver O'Halloran } 9053b6521f5SOliver O'Halloran 9065cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 9075cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 908c6f3c5eeSAneesh Kumar K.V 909c6f3c5eeSAneesh Kumar K.V out_unlock: 9105cad465dSMatthew Wilcox spin_unlock(ptl); 911c6f3c5eeSAneesh Kumar K.V if (pgtable) 912c6f3c5eeSAneesh Kumar K.V pte_free(mm, pgtable); 9135cad465dSMatthew Wilcox } 9145cad465dSMatthew Wilcox 9159a9731b1SThomas Hellstrom (VMware) /** 9167b806d22SLorenzo Stoakes * vmf_insert_pfn_pmd - insert a pmd size pfn 9179a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 9189a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 9199a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 9209a9731b1SThomas Hellstrom (VMware) * 9217b806d22SLorenzo Stoakes * Insert a pmd size pfn. See vmf_insert_pfn() for additional info. 9229a9731b1SThomas Hellstrom (VMware) * 9239a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 9249a9731b1SThomas Hellstrom (VMware) */ 9257b806d22SLorenzo Stoakes vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) 9265cad465dSMatthew Wilcox { 927fce86ff5SDan Williams unsigned long addr = vmf->address & PMD_MASK; 928fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 9297b806d22SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 9303b6521f5SOliver O'Halloran pgtable_t pgtable = NULL; 931fce86ff5SDan Williams 9325cad465dSMatthew Wilcox /* 9335cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 9345cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 9355cad465dSMatthew Wilcox * can't support a 'special' bit. 9365cad465dSMatthew Wilcox */ 937e1fb4a08SDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 938e1fb4a08SDave Jiang !pfn_t_devmap(pfn)); 9395cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 9405cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 9415cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 9425cad465dSMatthew Wilcox 9435cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 9445cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 945308a047cSBorislav Petkov 9463b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) { 9474cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 9483b6521f5SOliver O'Halloran if (!pgtable) 9493b6521f5SOliver O'Halloran return VM_FAULT_OOM; 9503b6521f5SOliver O'Halloran } 9513b6521f5SOliver O'Halloran 952308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 953308a047cSBorislav Petkov 954fce86ff5SDan Williams insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); 955ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 9565cad465dSMatthew Wilcox } 9577b806d22SLorenzo Stoakes EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); 9585cad465dSMatthew Wilcox 959a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 960f55e1014SLinus Torvalds static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 961a00cc7d9SMatthew Wilcox { 962f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 963a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 964a00cc7d9SMatthew Wilcox return pud; 965a00cc7d9SMatthew Wilcox } 966a00cc7d9SMatthew Wilcox 967a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 9687b806d22SLorenzo Stoakes pud_t *pud, pfn_t pfn, bool write) 969a00cc7d9SMatthew Wilcox { 970a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 9717b806d22SLorenzo Stoakes pgprot_t prot = vma->vm_page_prot; 972a00cc7d9SMatthew Wilcox pud_t entry; 973a00cc7d9SMatthew Wilcox spinlock_t *ptl; 974a00cc7d9SMatthew Wilcox 975a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 976c6f3c5eeSAneesh Kumar K.V if (!pud_none(*pud)) { 977c6f3c5eeSAneesh Kumar K.V if (write) { 978c6f3c5eeSAneesh Kumar K.V if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { 979c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pud(*pud)); 980c6f3c5eeSAneesh Kumar K.V goto out_unlock; 981c6f3c5eeSAneesh Kumar K.V } 982c6f3c5eeSAneesh Kumar K.V entry = pud_mkyoung(*pud); 983c6f3c5eeSAneesh Kumar K.V entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); 984c6f3c5eeSAneesh Kumar K.V if (pudp_set_access_flags(vma, addr, pud, entry, 1)) 985c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pud(vma, addr, pud); 986c6f3c5eeSAneesh Kumar K.V } 987c6f3c5eeSAneesh Kumar K.V goto out_unlock; 988c6f3c5eeSAneesh Kumar K.V } 989c6f3c5eeSAneesh Kumar K.V 990a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 991a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 992a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 993a00cc7d9SMatthew Wilcox if (write) { 994f55e1014SLinus Torvalds entry = pud_mkyoung(pud_mkdirty(entry)); 995f55e1014SLinus Torvalds entry = maybe_pud_mkwrite(entry, vma); 996a00cc7d9SMatthew Wilcox } 997a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 998a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 999c6f3c5eeSAneesh Kumar K.V 1000c6f3c5eeSAneesh Kumar K.V out_unlock: 1001a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1002a00cc7d9SMatthew Wilcox } 1003a00cc7d9SMatthew Wilcox 10049a9731b1SThomas Hellstrom (VMware) /** 10057b806d22SLorenzo Stoakes * vmf_insert_pfn_pud - insert a pud size pfn 10069a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 10079a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 10089a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 10099a9731b1SThomas Hellstrom (VMware) * 10107b806d22SLorenzo Stoakes * Insert a pud size pfn. See vmf_insert_pfn() for additional info. 10119a9731b1SThomas Hellstrom (VMware) * 10129a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 10139a9731b1SThomas Hellstrom (VMware) */ 10147b806d22SLorenzo Stoakes vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) 1015a00cc7d9SMatthew Wilcox { 1016fce86ff5SDan Williams unsigned long addr = vmf->address & PUD_MASK; 1017fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 10187b806d22SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 1019fce86ff5SDan Williams 1020a00cc7d9SMatthew Wilcox /* 1021a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 1022a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 1023a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 1024a00cc7d9SMatthew Wilcox */ 102562ec0d8cSDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 102662ec0d8cSDave Jiang !pfn_t_devmap(pfn)); 1027a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 1028a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 1029a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 1030a00cc7d9SMatthew Wilcox 1031a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 1032a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 1033a00cc7d9SMatthew Wilcox 1034a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 1035a00cc7d9SMatthew Wilcox 10367b806d22SLorenzo Stoakes insert_pfn_pud(vma, addr, vmf->pud, pfn, write); 1037a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 1038a00cc7d9SMatthew Wilcox } 10397b806d22SLorenzo Stoakes EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); 1040a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1041a00cc7d9SMatthew Wilcox 10423565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 1043a69e4717SMiaohe Lin pmd_t *pmd, bool write) 10443565fce3SDan Williams { 10453565fce3SDan Williams pmd_t _pmd; 10463565fce3SDan Williams 1047a8f97366SKirill A. Shutemov _pmd = pmd_mkyoung(*pmd); 1048a69e4717SMiaohe Lin if (write) 1049a8f97366SKirill A. Shutemov _pmd = pmd_mkdirty(_pmd); 10503565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 1051a69e4717SMiaohe Lin pmd, _pmd, write)) 10523565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 10533565fce3SDan Williams } 10543565fce3SDan Williams 10553565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 1056df06b37fSKeith Busch pmd_t *pmd, int flags, struct dev_pagemap **pgmap) 10573565fce3SDan Williams { 10583565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 10593565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 10603565fce3SDan Williams struct page *page; 10610f089235SLogan Gunthorpe int ret; 10623565fce3SDan Williams 10633565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 10643565fce3SDan Williams 1065f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pmd_write(*pmd)) 10663565fce3SDan Williams return NULL; 10673565fce3SDan Williams 10683565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 10693565fce3SDan Williams /* pass */; 10703565fce3SDan Williams else 10713565fce3SDan Williams return NULL; 10723565fce3SDan Williams 10733565fce3SDan Williams if (flags & FOLL_TOUCH) 1074a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 10753565fce3SDan Williams 10763565fce3SDan Williams /* 10773565fce3SDan Williams * device mapped pages can only be returned if the 10783565fce3SDan Williams * caller will manage the page reference count. 10793565fce3SDan Williams */ 10803faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 10813565fce3SDan Williams return ERR_PTR(-EEXIST); 10823565fce3SDan Williams 10833565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 1084df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1085df06b37fSKeith Busch if (!*pgmap) 10863565fce3SDan Williams return ERR_PTR(-EFAULT); 10873565fce3SDan Williams page = pfn_to_page(pfn); 10880f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 10890f089235SLogan Gunthorpe if (ret) 10900f089235SLogan Gunthorpe page = ERR_PTR(ret); 10913565fce3SDan Williams 10923565fce3SDan Williams return page; 10933565fce3SDan Williams } 10943565fce3SDan Williams 109571e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 109671e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 10978f34f1eaSPeter Xu struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 109871e3aac0SAndrea Arcangeli { 1099c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 110071e3aac0SAndrea Arcangeli struct page *src_page; 110171e3aac0SAndrea Arcangeli pmd_t pmd; 110212c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 1103628d47ceSKirill A. Shutemov int ret = -ENOMEM; 110471e3aac0SAndrea Arcangeli 1105628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 11068f34f1eaSPeter Xu if (!vma_is_anonymous(dst_vma)) 1107628d47ceSKirill A. Shutemov return 0; 1108628d47ceSKirill A. Shutemov 11094cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(dst_mm); 111071e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 111171e3aac0SAndrea Arcangeli goto out; 111271e3aac0SAndrea Arcangeli 1113c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 1114c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 1115c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 111671e3aac0SAndrea Arcangeli 111771e3aac0SAndrea Arcangeli ret = -EAGAIN; 111871e3aac0SAndrea Arcangeli pmd = *src_pmd; 111984c3fc4eSZi Yan 112084c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 112184c3fc4eSZi Yan if (unlikely(is_swap_pmd(pmd))) { 112284c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(pmd); 112384c3fc4eSZi Yan 112484c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(pmd)); 11256c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) { 11264dd845b5SAlistair Popple entry = make_readable_migration_entry( 11274dd845b5SAlistair Popple swp_offset(entry)); 112884c3fc4eSZi Yan pmd = swp_entry_to_pmd(entry); 1129ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*src_pmd)) 1130ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 11318f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*src_pmd)) 11328f34f1eaSPeter Xu pmd = pmd_swp_mkuffd_wp(pmd); 113384c3fc4eSZi Yan set_pmd_at(src_mm, addr, src_pmd, pmd); 113484c3fc4eSZi Yan } 1135dd8a67f9SZi Yan add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1136af5b0f6aSKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 1137dd8a67f9SZi Yan pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 11388f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11398f34f1eaSPeter Xu pmd = pmd_swp_clear_uffd_wp(pmd); 114084c3fc4eSZi Yan set_pmd_at(dst_mm, addr, dst_pmd, pmd); 114184c3fc4eSZi Yan ret = 0; 114284c3fc4eSZi Yan goto out_unlock; 114384c3fc4eSZi Yan } 114484c3fc4eSZi Yan #endif 114584c3fc4eSZi Yan 1146628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 114771e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 114871e3aac0SAndrea Arcangeli goto out_unlock; 114971e3aac0SAndrea Arcangeli } 1150fc9fe822SKirill A. Shutemov /* 1151c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 1152fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 1153fc9fe822SKirill A. Shutemov * a page table. 1154fc9fe822SKirill A. Shutemov */ 1155fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 115697ae1749SKirill A. Shutemov /* 115797ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 115897ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 115997ae1749SKirill A. Shutemov * reference. 116097ae1749SKirill A. Shutemov */ 11615fc7a5f6SPeter Xu mm_get_huge_zero_page(dst_mm); 11625fc7a5f6SPeter Xu goto out_zero_page; 1163fc9fe822SKirill A. Shutemov } 1164de466bd6SMel Gorman 116571e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 1166309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 1167d042035eSPeter Xu 1168fb3d824dSDavid Hildenbrand get_page(src_page); 1169fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { 1170fb3d824dSDavid Hildenbrand /* Page maybe pinned: split and retry the fault on PTEs. */ 1171fb3d824dSDavid Hildenbrand put_page(src_page); 1172d042035eSPeter Xu pte_free(dst_mm, pgtable); 1173d042035eSPeter Xu spin_unlock(src_ptl); 1174d042035eSPeter Xu spin_unlock(dst_ptl); 11758f34f1eaSPeter Xu __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); 1176d042035eSPeter Xu return -EAGAIN; 1177d042035eSPeter Xu } 117871e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 11795fc7a5f6SPeter Xu out_zero_page: 1180c4812909SKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 11815c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 118271e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 11838f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11848f34f1eaSPeter Xu pmd = pmd_clear_uffd_wp(pmd); 118571e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 118671e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 118771e3aac0SAndrea Arcangeli 118871e3aac0SAndrea Arcangeli ret = 0; 118971e3aac0SAndrea Arcangeli out_unlock: 1190c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 1191c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 119271e3aac0SAndrea Arcangeli out: 119371e3aac0SAndrea Arcangeli return ret; 119471e3aac0SAndrea Arcangeli } 119571e3aac0SAndrea Arcangeli 1196a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1197a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 11985fe653e9SMiaohe Lin pud_t *pud, bool write) 1199a00cc7d9SMatthew Wilcox { 1200a00cc7d9SMatthew Wilcox pud_t _pud; 1201a00cc7d9SMatthew Wilcox 1202a8f97366SKirill A. Shutemov _pud = pud_mkyoung(*pud); 12035fe653e9SMiaohe Lin if (write) 1204a8f97366SKirill A. Shutemov _pud = pud_mkdirty(_pud); 1205a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 12065fe653e9SMiaohe Lin pud, _pud, write)) 1207a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1208a00cc7d9SMatthew Wilcox } 1209a00cc7d9SMatthew Wilcox 1210a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 1211df06b37fSKeith Busch pud_t *pud, int flags, struct dev_pagemap **pgmap) 1212a00cc7d9SMatthew Wilcox { 1213a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 1214a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1215a00cc7d9SMatthew Wilcox struct page *page; 12160f089235SLogan Gunthorpe int ret; 1217a00cc7d9SMatthew Wilcox 1218a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 1219a00cc7d9SMatthew Wilcox 1220f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pud_write(*pud)) 1221a00cc7d9SMatthew Wilcox return NULL; 1222a00cc7d9SMatthew Wilcox 1223a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 1224a00cc7d9SMatthew Wilcox /* pass */; 1225a00cc7d9SMatthew Wilcox else 1226a00cc7d9SMatthew Wilcox return NULL; 1227a00cc7d9SMatthew Wilcox 1228a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 12295fe653e9SMiaohe Lin touch_pud(vma, addr, pud, flags & FOLL_WRITE); 1230a00cc7d9SMatthew Wilcox 1231a00cc7d9SMatthew Wilcox /* 1232a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 1233a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 12343faa52c0SJohn Hubbard * 12353faa52c0SJohn Hubbard * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: 1236a00cc7d9SMatthew Wilcox */ 12373faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 1238a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 1239a00cc7d9SMatthew Wilcox 1240a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 1241df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1242df06b37fSKeith Busch if (!*pgmap) 1243a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 1244a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 12450f089235SLogan Gunthorpe 12460f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 12470f089235SLogan Gunthorpe if (ret) 12480f089235SLogan Gunthorpe page = ERR_PTR(ret); 1249a00cc7d9SMatthew Wilcox 1250a00cc7d9SMatthew Wilcox return page; 1251a00cc7d9SMatthew Wilcox } 1252a00cc7d9SMatthew Wilcox 1253a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1254a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1255a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1256a00cc7d9SMatthew Wilcox { 1257a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1258a00cc7d9SMatthew Wilcox pud_t pud; 1259a00cc7d9SMatthew Wilcox int ret; 1260a00cc7d9SMatthew Wilcox 1261a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1262a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1263a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1264a00cc7d9SMatthew Wilcox 1265a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1266a00cc7d9SMatthew Wilcox pud = *src_pud; 1267a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1268a00cc7d9SMatthew Wilcox goto out_unlock; 1269a00cc7d9SMatthew Wilcox 1270a00cc7d9SMatthew Wilcox /* 1271a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1272a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1273a00cc7d9SMatthew Wilcox * a page table. 1274a00cc7d9SMatthew Wilcox */ 1275a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1276a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1277a00cc7d9SMatthew Wilcox } 1278a00cc7d9SMatthew Wilcox 1279fb3d824dSDavid Hildenbrand /* 1280fb3d824dSDavid Hildenbrand * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() 1281fb3d824dSDavid Hildenbrand * and split if duplicating fails. 1282fb3d824dSDavid Hildenbrand */ 1283a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1284a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1285a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1286a00cc7d9SMatthew Wilcox 1287a00cc7d9SMatthew Wilcox ret = 0; 1288a00cc7d9SMatthew Wilcox out_unlock: 1289a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1290a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1291a00cc7d9SMatthew Wilcox return ret; 1292a00cc7d9SMatthew Wilcox } 1293a00cc7d9SMatthew Wilcox 1294a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1295a00cc7d9SMatthew Wilcox { 1296a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1297a00cc7d9SMatthew Wilcox 1298a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1299a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1300a00cc7d9SMatthew Wilcox goto unlock; 1301a00cc7d9SMatthew Wilcox 13025fe653e9SMiaohe Lin touch_pud(vmf->vma, vmf->address, vmf->pud, write); 1303a00cc7d9SMatthew Wilcox unlock: 1304a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1305a00cc7d9SMatthew Wilcox } 1306a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1307a00cc7d9SMatthew Wilcox 13085db4f15cSYang Shi void huge_pmd_set_accessed(struct vm_fault *vmf) 1309a1dd450bSWill Deacon { 131020f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1311a1dd450bSWill Deacon 131282b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 1313a69e4717SMiaohe Lin if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) 1314a1dd450bSWill Deacon goto unlock; 1315a1dd450bSWill Deacon 1316a69e4717SMiaohe Lin touch_pmd(vmf->vma, vmf->address, vmf->pmd, write); 1317a1dd450bSWill Deacon 1318a1dd450bSWill Deacon unlock: 131982b0f8c3SJan Kara spin_unlock(vmf->ptl); 1320a1dd450bSWill Deacon } 1321a1dd450bSWill Deacon 13225db4f15cSYang Shi vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) 132371e3aac0SAndrea Arcangeli { 1324c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 132582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 13262fad3d14SMatthew Wilcox (Oracle) struct folio *folio; 13273917c802SKirill A. Shutemov struct page *page; 132882b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 13295db4f15cSYang Shi pmd_t orig_pmd = vmf->orig_pmd; 133071e3aac0SAndrea Arcangeli 133182b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 133281d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 13333917c802SKirill A. Shutemov 133493b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 13353917c802SKirill A. Shutemov goto fallback; 13363917c802SKirill A. Shutemov 133782b0f8c3SJan Kara spin_lock(vmf->ptl); 13383917c802SKirill A. Shutemov 13393917c802SKirill A. Shutemov if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13403917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13413917c802SKirill A. Shutemov return 0; 13423917c802SKirill A. Shutemov } 134371e3aac0SAndrea Arcangeli 134471e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 13452fad3d14SMatthew Wilcox (Oracle) folio = page_folio(page); 1346f6004e73SMiaohe Lin VM_BUG_ON_PAGE(!PageHead(page), page); 13473917c802SKirill A. Shutemov 13486c287605SDavid Hildenbrand /* Early check when only holding the PT lock. */ 13496c287605SDavid Hildenbrand if (PageAnonExclusive(page)) 13506c287605SDavid Hildenbrand goto reuse; 13516c287605SDavid Hildenbrand 13522fad3d14SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) { 13532fad3d14SMatthew Wilcox (Oracle) folio_get(folio); 1354ba3c4ce6SHuang Ying spin_unlock(vmf->ptl); 13552fad3d14SMatthew Wilcox (Oracle) folio_lock(folio); 1356ba3c4ce6SHuang Ying spin_lock(vmf->ptl); 1357ba3c4ce6SHuang Ying if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13583917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13592fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13602fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 13613917c802SKirill A. Shutemov return 0; 1362ba3c4ce6SHuang Ying } 13632fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 1364ba3c4ce6SHuang Ying } 13653917c802SKirill A. Shutemov 13666c287605SDavid Hildenbrand /* Recheck after temporarily dropping the PT lock. */ 13676c287605SDavid Hildenbrand if (PageAnonExclusive(page)) { 13682fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13696c287605SDavid Hildenbrand goto reuse; 13706c287605SDavid Hildenbrand } 13716c287605SDavid Hildenbrand 13723917c802SKirill A. Shutemov /* 13732fad3d14SMatthew Wilcox (Oracle) * See do_wp_page(): we can only reuse the folio exclusively if 13742fad3d14SMatthew Wilcox (Oracle) * there are no additional references. Note that we always drain 13751fec6890SMatthew Wilcox (Oracle) * the LRU cache immediately after adding a THP. 13763917c802SKirill A. Shutemov */ 13772fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) > 13782fad3d14SMatthew Wilcox (Oracle) 1 + folio_test_swapcache(folio) * folio_nr_pages(folio)) 13793bff7e3fSDavid Hildenbrand goto unlock_fallback; 13802fad3d14SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 13812fad3d14SMatthew Wilcox (Oracle) folio_free_swap(folio); 13822fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) == 1) { 138371e3aac0SAndrea Arcangeli pmd_t entry; 13846c54dc6cSDavid Hildenbrand 138506968625SDavid Hildenbrand folio_move_anon_rmap(folio, vma); 13865ca43289SDavid Hildenbrand SetPageAnonExclusive(page); 13872fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13886c287605SDavid Hildenbrand reuse: 1389c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 1390c89357e2SDavid Hildenbrand spin_unlock(vmf->ptl); 1391c89357e2SDavid Hildenbrand return 0; 1392c89357e2SDavid Hildenbrand } 139371e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 1394f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 139582b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 139682b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 13973917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 1398cb8d8633SDavid Hildenbrand return 0; 139971e3aac0SAndrea Arcangeli } 14003917c802SKirill A. Shutemov 14013bff7e3fSDavid Hildenbrand unlock_fallback: 14022fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 140382b0f8c3SJan Kara spin_unlock(vmf->ptl); 14043917c802SKirill A. Shutemov fallback: 14053917c802SKirill A. Shutemov __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); 14063917c802SKirill A. Shutemov return VM_FAULT_FALLBACK; 140771e3aac0SAndrea Arcangeli } 140871e3aac0SAndrea Arcangeli 1409c27f479eSDavid Hildenbrand static inline bool can_change_pmd_writable(struct vm_area_struct *vma, 1410c27f479eSDavid Hildenbrand unsigned long addr, pmd_t pmd) 1411c27f479eSDavid Hildenbrand { 1412c27f479eSDavid Hildenbrand struct page *page; 1413c27f479eSDavid Hildenbrand 1414c27f479eSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) 1415c27f479eSDavid Hildenbrand return false; 1416c27f479eSDavid Hildenbrand 1417c27f479eSDavid Hildenbrand /* Don't touch entries that are not even readable (NUMA hinting). */ 1418c27f479eSDavid Hildenbrand if (pmd_protnone(pmd)) 1419c27f479eSDavid Hildenbrand return false; 1420c27f479eSDavid Hildenbrand 1421c27f479eSDavid Hildenbrand /* Do we need write faults for softdirty tracking? */ 1422c27f479eSDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 1423c27f479eSDavid Hildenbrand return false; 1424c27f479eSDavid Hildenbrand 1425c27f479eSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 1426c27f479eSDavid Hildenbrand if (userfaultfd_huge_pmd_wp(vma, pmd)) 1427c27f479eSDavid Hildenbrand return false; 1428c27f479eSDavid Hildenbrand 1429c27f479eSDavid Hildenbrand if (!(vma->vm_flags & VM_SHARED)) { 1430c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1431c27f479eSDavid Hildenbrand page = vm_normal_page_pmd(vma, addr, pmd); 1432c27f479eSDavid Hildenbrand return page && PageAnon(page) && PageAnonExclusive(page); 1433c27f479eSDavid Hildenbrand } 1434c27f479eSDavid Hildenbrand 1435c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1436c27f479eSDavid Hildenbrand return pmd_dirty(pmd); 1437c27f479eSDavid Hildenbrand } 1438c27f479eSDavid Hildenbrand 14395535be30SDavid Hildenbrand /* FOLL_FORCE can write to even unwritable PMDs in COW mappings. */ 14405535be30SDavid Hildenbrand static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, 14415535be30SDavid Hildenbrand struct vm_area_struct *vma, 14425535be30SDavid Hildenbrand unsigned int flags) 14438310d48bSKeno Fischer { 14445535be30SDavid Hildenbrand /* If the pmd is writable, we can write to the page. */ 14455535be30SDavid Hildenbrand if (pmd_write(pmd)) 14465535be30SDavid Hildenbrand return true; 14475535be30SDavid Hildenbrand 14485535be30SDavid Hildenbrand /* Maybe FOLL_FORCE is set to override it? */ 14495535be30SDavid Hildenbrand if (!(flags & FOLL_FORCE)) 14505535be30SDavid Hildenbrand return false; 14515535be30SDavid Hildenbrand 14525535be30SDavid Hildenbrand /* But FOLL_FORCE has no effect on shared mappings */ 14535535be30SDavid Hildenbrand if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED)) 14545535be30SDavid Hildenbrand return false; 14555535be30SDavid Hildenbrand 14565535be30SDavid Hildenbrand /* ... or read-only private ones */ 14575535be30SDavid Hildenbrand if (!(vma->vm_flags & VM_MAYWRITE)) 14585535be30SDavid Hildenbrand return false; 14595535be30SDavid Hildenbrand 14605535be30SDavid Hildenbrand /* ... or already writable ones that just need to take a write fault */ 14615535be30SDavid Hildenbrand if (vma->vm_flags & VM_WRITE) 14625535be30SDavid Hildenbrand return false; 14635535be30SDavid Hildenbrand 14645535be30SDavid Hildenbrand /* 14655535be30SDavid Hildenbrand * See can_change_pte_writable(): we broke COW and could map the page 14665535be30SDavid Hildenbrand * writable if we have an exclusive anonymous page ... 14675535be30SDavid Hildenbrand */ 14685535be30SDavid Hildenbrand if (!page || !PageAnon(page) || !PageAnonExclusive(page)) 14695535be30SDavid Hildenbrand return false; 14705535be30SDavid Hildenbrand 14715535be30SDavid Hildenbrand /* ... and a write-fault isn't required for other reasons. */ 14725535be30SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 14735535be30SDavid Hildenbrand return false; 14745535be30SDavid Hildenbrand return !userfaultfd_huge_pmd_wp(vma, pmd); 14758310d48bSKeno Fischer } 14768310d48bSKeno Fischer 1477b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 147871e3aac0SAndrea Arcangeli unsigned long addr, 147971e3aac0SAndrea Arcangeli pmd_t *pmd, 148071e3aac0SAndrea Arcangeli unsigned int flags) 148171e3aac0SAndrea Arcangeli { 1482b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 14835535be30SDavid Hildenbrand struct page *page; 14840f089235SLogan Gunthorpe int ret; 148571e3aac0SAndrea Arcangeli 1486c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 148771e3aac0SAndrea Arcangeli 14885535be30SDavid Hildenbrand page = pmd_page(*pmd); 14895535be30SDavid Hildenbrand VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 14905535be30SDavid Hildenbrand 14915535be30SDavid Hildenbrand if ((flags & FOLL_WRITE) && 14925535be30SDavid Hildenbrand !can_follow_write_pmd(*pmd, page, vma, flags)) 14935535be30SDavid Hildenbrand return NULL; 149471e3aac0SAndrea Arcangeli 149585facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 149685facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 149785facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 149885facf25SKirill A. Shutemov 1499d74943a2SDavid Hildenbrand if (pmd_protnone(*pmd) && !gup_can_follow_protnone(vma, flags)) 15005535be30SDavid Hildenbrand return NULL; 15013faa52c0SJohn Hubbard 150284209e87SDavid Hildenbrand if (!pmd_write(*pmd) && gup_must_unshare(vma, flags, page)) 1503a7f22660SDavid Hildenbrand return ERR_PTR(-EMLINK); 1504a7f22660SDavid Hildenbrand 1505b6a2619cSDavid Hildenbrand VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && 1506b6a2619cSDavid Hildenbrand !PageAnonExclusive(page), page); 1507b6a2619cSDavid Hildenbrand 15080f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 15090f089235SLogan Gunthorpe if (ret) 15100f089235SLogan Gunthorpe return ERR_PTR(ret); 15113faa52c0SJohn Hubbard 15123565fce3SDan Williams if (flags & FOLL_TOUCH) 1513a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 15143faa52c0SJohn Hubbard 151571e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1516ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 151771e3aac0SAndrea Arcangeli 151871e3aac0SAndrea Arcangeli return page; 151971e3aac0SAndrea Arcangeli } 152071e3aac0SAndrea Arcangeli 1521d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 15225db4f15cSYang Shi vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) 1523d10e63f2SMel Gorman { 152482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1525c5b5a3ddSYang Shi pmd_t oldpmd = vmf->orig_pmd; 1526c5b5a3ddSYang Shi pmd_t pmd; 1527667ffc31SKefeng Wang struct folio *folio; 152882b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 1529667ffc31SKefeng Wang int nid = NUMA_NO_NODE; 153033024536SHuang Ying int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); 15316a56ccbcSDavid Hildenbrand bool migrated = false, writable = false; 15326688cc05SPeter Zijlstra int flags = 0; 1533d10e63f2SMel Gorman 153482b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1535c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 153682b0f8c3SJan Kara spin_unlock(vmf->ptl); 1537de466bd6SMel Gorman goto out; 1538de466bd6SMel Gorman } 1539de466bd6SMel Gorman 1540c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 15416a56ccbcSDavid Hildenbrand 15426a56ccbcSDavid Hildenbrand /* 15436a56ccbcSDavid Hildenbrand * Detect now whether the PMD could be writable; this information 15446a56ccbcSDavid Hildenbrand * is only valid while holding the PT lock. 15456a56ccbcSDavid Hildenbrand */ 15466a56ccbcSDavid Hildenbrand writable = pmd_write(pmd); 15476a56ccbcSDavid Hildenbrand if (!writable && vma_wants_manual_pte_write_upgrade(vma) && 15486a56ccbcSDavid Hildenbrand can_change_pmd_writable(vma, vmf->address, pmd)) 15496a56ccbcSDavid Hildenbrand writable = true; 15506a56ccbcSDavid Hildenbrand 1551667ffc31SKefeng Wang folio = vm_normal_folio_pmd(vma, haddr, pmd); 1552667ffc31SKefeng Wang if (!folio) 1553c5b5a3ddSYang Shi goto out_map; 1554c5b5a3ddSYang Shi 1555c5b5a3ddSYang Shi /* See similar comment in do_numa_page for explanation */ 15566a56ccbcSDavid Hildenbrand if (!writable) 1557c5b5a3ddSYang Shi flags |= TNF_NO_GROUP; 1558c5b5a3ddSYang Shi 1559667ffc31SKefeng Wang nid = folio_nid(folio); 156033024536SHuang Ying /* 156133024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 156233024536SHuang Ying * to record page access time. So use default value. 156333024536SHuang Ying */ 1564667ffc31SKefeng Wang if (node_is_toptier(nid)) 1565c4a8d2faSKefeng Wang last_cpupid = folio_last_cpupid(folio); 1566cda6d936SKefeng Wang target_nid = numa_migrate_prep(folio, vma, haddr, nid, &flags); 1567c5b5a3ddSYang Shi if (target_nid == NUMA_NO_NODE) { 1568667ffc31SKefeng Wang folio_put(folio); 1569c5b5a3ddSYang Shi goto out_map; 1570c5b5a3ddSYang Shi } 1571c5b5a3ddSYang Shi 157282b0f8c3SJan Kara spin_unlock(vmf->ptl); 15736a56ccbcSDavid Hildenbrand writable = false; 15748b1b436dSPeter Zijlstra 1575667ffc31SKefeng Wang migrated = migrate_misplaced_folio(folio, vma, target_nid); 15766688cc05SPeter Zijlstra if (migrated) { 15776688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 1578667ffc31SKefeng Wang nid = target_nid; 1579c5b5a3ddSYang Shi } else { 1580074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1581c5b5a3ddSYang Shi vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1582c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 158382b0f8c3SJan Kara spin_unlock(vmf->ptl); 1584c5b5a3ddSYang Shi goto out; 1585c5b5a3ddSYang Shi } 1586c5b5a3ddSYang Shi goto out_map; 1587c5b5a3ddSYang Shi } 1588b8916634SMel Gorman 1589b8916634SMel Gorman out: 1590667ffc31SKefeng Wang if (nid != NUMA_NO_NODE) 1591667ffc31SKefeng Wang task_numa_fault(last_cpupid, nid, HPAGE_PMD_NR, flags); 15928191acbdSMel Gorman 1593d10e63f2SMel Gorman return 0; 1594c5b5a3ddSYang Shi 1595c5b5a3ddSYang Shi out_map: 1596c5b5a3ddSYang Shi /* Restore the PMD */ 1597c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 1598c5b5a3ddSYang Shi pmd = pmd_mkyoung(pmd); 15996a56ccbcSDavid Hildenbrand if (writable) 1600161e393cSRick Edgecombe pmd = pmd_mkwrite(pmd, vma); 1601c5b5a3ddSYang Shi set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 1602c5b5a3ddSYang Shi update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1603c5b5a3ddSYang Shi spin_unlock(vmf->ptl); 1604c5b5a3ddSYang Shi goto out; 1605d10e63f2SMel Gorman } 1606d10e63f2SMel Gorman 1607319904adSHuang Ying /* 1608319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1609319904adSHuang Ying * Otherwise, return false. 1610319904adSHuang Ying */ 1611319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1612b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1613b8d3c4c3SMinchan Kim { 1614b8d3c4c3SMinchan Kim spinlock_t *ptl; 1615b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1616fc986a38SKefeng Wang struct folio *folio; 1617b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1618319904adSHuang Ying bool ret = false; 1619b8d3c4c3SMinchan Kim 1620ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 162107e32661SAneesh Kumar K.V 1622b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1623b6ec57f4SKirill A. Shutemov if (!ptl) 162425eedabeSLinus Torvalds goto out_unlocked; 1625b8d3c4c3SMinchan Kim 1626b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1627319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1628b8d3c4c3SMinchan Kim goto out; 1629b8d3c4c3SMinchan Kim 163084c3fc4eSZi Yan if (unlikely(!pmd_present(orig_pmd))) { 163184c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 163284c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 163384c3fc4eSZi Yan goto out; 163484c3fc4eSZi Yan } 163584c3fc4eSZi Yan 1636fc986a38SKefeng Wang folio = pfn_folio(pmd_pfn(orig_pmd)); 1637b8d3c4c3SMinchan Kim /* 1638fc986a38SKefeng Wang * If other processes are mapping this folio, we couldn't discard 1639fc986a38SKefeng Wang * the folio unless they all do MADV_FREE so let's skip the folio. 1640b8d3c4c3SMinchan Kim */ 164120b18aadSYin Fengwei if (folio_estimated_sharers(folio) != 1) 1642b8d3c4c3SMinchan Kim goto out; 1643b8d3c4c3SMinchan Kim 1644fc986a38SKefeng Wang if (!folio_trylock(folio)) 1645b8d3c4c3SMinchan Kim goto out; 1646b8d3c4c3SMinchan Kim 1647b8d3c4c3SMinchan Kim /* 1648b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1649b8d3c4c3SMinchan Kim * will deactivate only them. 1650b8d3c4c3SMinchan Kim */ 1651b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1652fc986a38SKefeng Wang folio_get(folio); 1653b8d3c4c3SMinchan Kim spin_unlock(ptl); 1654fc986a38SKefeng Wang split_folio(folio); 1655fc986a38SKefeng Wang folio_unlock(folio); 1656fc986a38SKefeng Wang folio_put(folio); 1657b8d3c4c3SMinchan Kim goto out_unlocked; 1658b8d3c4c3SMinchan Kim } 1659b8d3c4c3SMinchan Kim 1660fc986a38SKefeng Wang if (folio_test_dirty(folio)) 1661fc986a38SKefeng Wang folio_clear_dirty(folio); 1662fc986a38SKefeng Wang folio_unlock(folio); 1663b8d3c4c3SMinchan Kim 1664b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 166558ceeb6bSKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1666b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1667b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1668b8d3c4c3SMinchan Kim 1669b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1670b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1671b8d3c4c3SMinchan Kim } 1672802a3a92SShaohua Li 16736a6fe9ebSKefeng Wang folio_mark_lazyfree(folio); 1674319904adSHuang Ying ret = true; 1675b8d3c4c3SMinchan Kim out: 1676b8d3c4c3SMinchan Kim spin_unlock(ptl); 1677b8d3c4c3SMinchan Kim out_unlocked: 1678b8d3c4c3SMinchan Kim return ret; 1679b8d3c4c3SMinchan Kim } 1680b8d3c4c3SMinchan Kim 1681953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1682953c66c2SAneesh Kumar K.V { 1683953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1684953c66c2SAneesh Kumar K.V 1685953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1686953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1687c4812909SKirill A. Shutemov mm_dec_nr_ptes(mm); 1688953c66c2SAneesh Kumar K.V } 1689953c66c2SAneesh Kumar K.V 169071e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1691f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 169271e3aac0SAndrea Arcangeli { 1693f5c8ad47SDavid Miller pmd_t orig_pmd; 1694da146769SKirill A. Shutemov spinlock_t *ptl; 1695da146769SKirill A. Shutemov 1696ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 169707e32661SAneesh Kumar K.V 1698b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1699b6ec57f4SKirill A. Shutemov if (!ptl) 1700da146769SKirill A. Shutemov return 0; 1701a6bf2bb0SAneesh Kumar K.V /* 1702a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 17038809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1704a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1705a6bf2bb0SAneesh Kumar K.V * operations. 1706a6bf2bb0SAneesh Kumar K.V */ 170793a98695SAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, 1708fcbe08d6SMartin Schwidefsky tlb->fullmm); 1709e5136e87SRick Edgecombe arch_check_zapped_pmd(vma, orig_pmd); 1710f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 17112484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 17123b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) 17133b6521f5SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 17144897c765SMatthew Wilcox spin_unlock(ptl); 1715da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1716c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1717bf929152SKirill A. Shutemov spin_unlock(ptl); 1718479f0abbSKirill A. Shutemov } else { 1719616b8371SZi Yan struct page *page = NULL; 1720616b8371SZi Yan int flush_needed = 1; 1721616b8371SZi Yan 1722616b8371SZi Yan if (pmd_present(orig_pmd)) { 1723616b8371SZi Yan page = pmd_page(orig_pmd); 1724cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 1725309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1726309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1727616b8371SZi Yan } else if (thp_migration_supported()) { 1728616b8371SZi Yan swp_entry_t entry; 1729616b8371SZi Yan 1730616b8371SZi Yan VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); 1731616b8371SZi Yan entry = pmd_to_swp_entry(orig_pmd); 1732af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1733616b8371SZi Yan flush_needed = 0; 1734616b8371SZi Yan } else 1735616b8371SZi Yan WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); 1736616b8371SZi Yan 1737b5072380SKirill A. Shutemov if (PageAnon(page)) { 1738c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1739b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1740b5072380SKirill A. Shutemov } else { 1741953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1742953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1743fadae295SYang Shi add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); 1744b5072380SKirill A. Shutemov } 1745616b8371SZi Yan 1746bf929152SKirill A. Shutemov spin_unlock(ptl); 1747616b8371SZi Yan if (flush_needed) 1748e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1749479f0abbSKirill A. Shutemov } 1750da146769SKirill A. Shutemov return 1; 175171e3aac0SAndrea Arcangeli } 175271e3aac0SAndrea Arcangeli 17531dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 17541dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 17551dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 17561dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 17571dd38b6cSAneesh Kumar K.V { 17581dd38b6cSAneesh Kumar K.V /* 17591dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 17601dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 17611dd38b6cSAneesh Kumar K.V * 17621dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 17631dd38b6cSAneesh Kumar K.V */ 17641dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 17651dd38b6cSAneesh Kumar K.V } 17661dd38b6cSAneesh Kumar K.V #endif 17671dd38b6cSAneesh Kumar K.V 1768ab6e3d09SNaoya Horiguchi static pmd_t move_soft_dirty_pmd(pmd_t pmd) 1769ab6e3d09SNaoya Horiguchi { 1770ab6e3d09SNaoya Horiguchi #ifdef CONFIG_MEM_SOFT_DIRTY 1771ab6e3d09SNaoya Horiguchi if (unlikely(is_pmd_migration_entry(pmd))) 1772ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 1773ab6e3d09SNaoya Horiguchi else if (pmd_present(pmd)) 1774ab6e3d09SNaoya Horiguchi pmd = pmd_mksoft_dirty(pmd); 1775ab6e3d09SNaoya Horiguchi #endif 1776ab6e3d09SNaoya Horiguchi return pmd; 1777ab6e3d09SNaoya Horiguchi } 1778ab6e3d09SNaoya Horiguchi 1779bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 1780b8aa9d9dSWei Yang unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) 178137a1c49aSAndrea Arcangeli { 1782bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 178337a1c49aSAndrea Arcangeli pmd_t pmd; 178437a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 17855d190420SAaron Lu bool force_flush = false; 178637a1c49aSAndrea Arcangeli 178737a1c49aSAndrea Arcangeli /* 178837a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 1789a5be621eSHugh Dickins * should have released it; but move_page_tables() might have already 1790a5be621eSHugh Dickins * inserted a page table, if racing against shmem/file collapse. 179137a1c49aSAndrea Arcangeli */ 1792a5be621eSHugh Dickins if (!pmd_none(*new_pmd)) { 179337a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 17944b471e88SKirill A. Shutemov return false; 179537a1c49aSAndrea Arcangeli } 179637a1c49aSAndrea Arcangeli 1797bf929152SKirill A. Shutemov /* 1798bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1799c1e8d7c6SMichel Lespinasse * ptlocks because exclusive mmap_lock prevents deadlock. 1800bf929152SKirill A. Shutemov */ 1801b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1802b6ec57f4SKirill A. Shutemov if (old_ptl) { 1803bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1804bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1805bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 18068809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1807eb66ae03SLinus Torvalds if (pmd_present(pmd)) 1808a2ce2666SAaron Lu force_flush = true; 180937a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 18103592806cSKirill A. Shutemov 18111dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1812b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 18133592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 18143592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 18153592806cSKirill A. Shutemov } 1816ab6e3d09SNaoya Horiguchi pmd = move_soft_dirty_pmd(pmd); 1817ab6e3d09SNaoya Horiguchi set_pmd_at(mm, new_addr, new_pmd, pmd); 18185d190420SAaron Lu if (force_flush) 18197c38f181SMiaohe Lin flush_pmd_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 1820eb66ae03SLinus Torvalds if (new_ptl != old_ptl) 1821eb66ae03SLinus Torvalds spin_unlock(new_ptl); 1822bf929152SKirill A. Shutemov spin_unlock(old_ptl); 18234b471e88SKirill A. Shutemov return true; 182437a1c49aSAndrea Arcangeli } 18254b471e88SKirill A. Shutemov return false; 182637a1c49aSAndrea Arcangeli } 182737a1c49aSAndrea Arcangeli 1828f123d74aSMel Gorman /* 1829f123d74aSMel Gorman * Returns 1830f123d74aSMel Gorman * - 0 if PMD could not be locked 1831f0953a1bSIngo Molnar * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary 1832e346e668SYang Shi * or if prot_numa but THP migration is not supported 1833f0953a1bSIngo Molnar * - HPAGE_PMD_NR if protections changed and TLB flush necessary 1834f123d74aSMel Gorman */ 18354a18419fSNadav Amit int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 18364a18419fSNadav Amit pmd_t *pmd, unsigned long addr, pgprot_t newprot, 18374a18419fSNadav Amit unsigned long cp_flags) 1838cd7548abSJohannes Weiner { 1839cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1840bf929152SKirill A. Shutemov spinlock_t *ptl; 1841c9fe6656SNadav Amit pmd_t oldpmd, entry; 184258705444SPeter Xu bool prot_numa = cp_flags & MM_CP_PROT_NUMA; 1843292924b2SPeter Xu bool uffd_wp = cp_flags & MM_CP_UFFD_WP; 1844292924b2SPeter Xu bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; 18456a56ccbcSDavid Hildenbrand int ret = 1; 1846cd7548abSJohannes Weiner 18474a18419fSNadav Amit tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 18484a18419fSNadav Amit 1849e346e668SYang Shi if (prot_numa && !thp_migration_supported()) 1850e346e668SYang Shi return 1; 1851e346e668SYang Shi 1852b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 18530a85e51dSKirill A. Shutemov if (!ptl) 18540a85e51dSKirill A. Shutemov return 0; 18550a85e51dSKirill A. Shutemov 185684c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 185784c3fc4eSZi Yan if (is_swap_pmd(*pmd)) { 185884c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(*pmd); 1859d986ba2bSKefeng Wang struct folio *folio = page_folio(pfn_swap_entry_to_page(entry)); 186024bf08c4SDavid Hildenbrand pmd_t newpmd; 186184c3fc4eSZi Yan 186284c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd)); 18634dd845b5SAlistair Popple if (is_writable_migration_entry(entry)) { 186484c3fc4eSZi Yan /* 186584c3fc4eSZi Yan * A protection check is difficult so 186684c3fc4eSZi Yan * just be safe and disable write 186784c3fc4eSZi Yan */ 1868d986ba2bSKefeng Wang if (folio_test_anon(folio)) 18696c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(swp_offset(entry)); 18706c287605SDavid Hildenbrand else 18716c287605SDavid Hildenbrand entry = make_readable_migration_entry(swp_offset(entry)); 187284c3fc4eSZi Yan newpmd = swp_entry_to_pmd(entry); 1873ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pmd)) 1874ab6e3d09SNaoya Horiguchi newpmd = pmd_swp_mksoft_dirty(newpmd); 187524bf08c4SDavid Hildenbrand } else { 187624bf08c4SDavid Hildenbrand newpmd = *pmd; 187784c3fc4eSZi Yan } 187824bf08c4SDavid Hildenbrand 187924bf08c4SDavid Hildenbrand if (uffd_wp) 188024bf08c4SDavid Hildenbrand newpmd = pmd_swp_mkuffd_wp(newpmd); 188124bf08c4SDavid Hildenbrand else if (uffd_wp_resolve) 188224bf08c4SDavid Hildenbrand newpmd = pmd_swp_clear_uffd_wp(newpmd); 188324bf08c4SDavid Hildenbrand if (!pmd_same(*pmd, newpmd)) 188424bf08c4SDavid Hildenbrand set_pmd_at(mm, addr, pmd, newpmd); 188584c3fc4eSZi Yan goto unlock; 188684c3fc4eSZi Yan } 188784c3fc4eSZi Yan #endif 188884c3fc4eSZi Yan 1889a1a3a2fcSHuang Ying if (prot_numa) { 1890d986ba2bSKefeng Wang struct folio *folio; 189133024536SHuang Ying bool toptier; 1892e944fd67SMel Gorman /* 1893e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1894e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1895e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1896e944fd67SMel Gorman */ 1897a1a3a2fcSHuang Ying if (is_huge_zero_pmd(*pmd)) 18980a85e51dSKirill A. Shutemov goto unlock; 1899e944fd67SMel Gorman 1900a1a3a2fcSHuang Ying if (pmd_protnone(*pmd)) 19010a85e51dSKirill A. Shutemov goto unlock; 19020a85e51dSKirill A. Shutemov 1903d986ba2bSKefeng Wang folio = page_folio(pmd_page(*pmd)); 1904d986ba2bSKefeng Wang toptier = node_is_toptier(folio_nid(folio)); 1905a1a3a2fcSHuang Ying /* 1906a1a3a2fcSHuang Ying * Skip scanning top tier node if normal numa 1907a1a3a2fcSHuang Ying * balancing is disabled 1908a1a3a2fcSHuang Ying */ 1909a1a3a2fcSHuang Ying if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && 191033024536SHuang Ying toptier) 1911a1a3a2fcSHuang Ying goto unlock; 191233024536SHuang Ying 191333024536SHuang Ying if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && 191433024536SHuang Ying !toptier) 1915d986ba2bSKefeng Wang folio_xchg_access_time(folio, 1916d986ba2bSKefeng Wang jiffies_to_msecs(jiffies)); 1917a1a3a2fcSHuang Ying } 1918ced10803SKirill A. Shutemov /* 19193e4e28c5SMichel Lespinasse * In case prot_numa, we are under mmap_read_lock(mm). It's critical 1920ced10803SKirill A. Shutemov * to not clear pmd intermittently to avoid race with MADV_DONTNEED 19213e4e28c5SMichel Lespinasse * which is also under mmap_read_lock(mm): 1922ced10803SKirill A. Shutemov * 1923ced10803SKirill A. Shutemov * CPU0: CPU1: 1924ced10803SKirill A. Shutemov * change_huge_pmd(prot_numa=1) 1925ced10803SKirill A. Shutemov * pmdp_huge_get_and_clear_notify() 1926ced10803SKirill A. Shutemov * madvise_dontneed() 1927ced10803SKirill A. Shutemov * zap_pmd_range() 1928ced10803SKirill A. Shutemov * pmd_trans_huge(*pmd) == 0 (without ptl) 1929ced10803SKirill A. Shutemov * // skip the pmd 1930ced10803SKirill A. Shutemov * set_pmd_at(); 1931ced10803SKirill A. Shutemov * // pmd is re-established 1932ced10803SKirill A. Shutemov * 1933ced10803SKirill A. Shutemov * The race makes MADV_DONTNEED miss the huge pmd and don't clear it 1934ced10803SKirill A. Shutemov * which may break userspace. 1935ced10803SKirill A. Shutemov * 19364f831457SNadav Amit * pmdp_invalidate_ad() is required to make sure we don't miss 1937ced10803SKirill A. Shutemov * dirty/young flags set by hardware. 1938ced10803SKirill A. Shutemov */ 19394f831457SNadav Amit oldpmd = pmdp_invalidate_ad(vma, addr, pmd); 1940ced10803SKirill A. Shutemov 1941c9fe6656SNadav Amit entry = pmd_modify(oldpmd, newprot); 1942f1eb1bacSPeter Xu if (uffd_wp) 1943292924b2SPeter Xu entry = pmd_mkuffd_wp(entry); 1944f1eb1bacSPeter Xu else if (uffd_wp_resolve) 1945292924b2SPeter Xu /* 1946292924b2SPeter Xu * Leave the write bit to be handled by PF interrupt 1947292924b2SPeter Xu * handler, then things like COW could be properly 1948292924b2SPeter Xu * handled. 1949292924b2SPeter Xu */ 1950292924b2SPeter Xu entry = pmd_clear_uffd_wp(entry); 1951c27f479eSDavid Hildenbrand 1952c27f479eSDavid Hildenbrand /* See change_pte_range(). */ 1953c27f479eSDavid Hildenbrand if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && !pmd_write(entry) && 1954c27f479eSDavid Hildenbrand can_change_pmd_writable(vma, addr, entry)) 1955161e393cSRick Edgecombe entry = pmd_mkwrite(entry, vma); 1956c27f479eSDavid Hildenbrand 1957f123d74aSMel Gorman ret = HPAGE_PMD_NR; 195856eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 19594a18419fSNadav Amit 1960c9fe6656SNadav Amit if (huge_pmd_needs_flush(oldpmd, entry)) 19614a18419fSNadav Amit tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); 19620a85e51dSKirill A. Shutemov unlock: 1963bf929152SKirill A. Shutemov spin_unlock(ptl); 1964cd7548abSJohannes Weiner return ret; 1965cd7548abSJohannes Weiner } 1966cd7548abSJohannes Weiner 1967025c5b24SNaoya Horiguchi /* 19688f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 1969025c5b24SNaoya Horiguchi * 19708f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 19718f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 1972025c5b24SNaoya Horiguchi */ 1973b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1974025c5b24SNaoya Horiguchi { 1975b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 1976b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 197784c3fc4eSZi Yan if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || 197884c3fc4eSZi Yan pmd_devmap(*pmd))) 1979b6ec57f4SKirill A. Shutemov return ptl; 1980b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 1981b6ec57f4SKirill A. Shutemov return NULL; 1982025c5b24SNaoya Horiguchi } 1983025c5b24SNaoya Horiguchi 1984a00cc7d9SMatthew Wilcox /* 1985d965e390SMiaohe Lin * Returns page table lock pointer if a given pud maps a thp, NULL otherwise. 1986a00cc7d9SMatthew Wilcox * 1987d965e390SMiaohe Lin * Note that if it returns page table lock pointer, this routine returns without 1988d965e390SMiaohe Lin * unlocking page table lock. So callers must unlock it. 1989a00cc7d9SMatthew Wilcox */ 1990a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 1991a00cc7d9SMatthew Wilcox { 1992a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1993a00cc7d9SMatthew Wilcox 1994a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 1995a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 1996a00cc7d9SMatthew Wilcox return ptl; 1997a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1998a00cc7d9SMatthew Wilcox return NULL; 1999a00cc7d9SMatthew Wilcox } 2000a00cc7d9SMatthew Wilcox 2001a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 2002a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 2003a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 2004a00cc7d9SMatthew Wilcox { 2005a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2006a00cc7d9SMatthew Wilcox 2007a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 2008a00cc7d9SMatthew Wilcox if (!ptl) 2009a00cc7d9SMatthew Wilcox return 0; 201074929079SMiaohe Lin 2011f32928abSAneesh Kumar K.V pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm); 2012a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 20132484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 2014a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2015a00cc7d9SMatthew Wilcox /* No zero page support yet */ 2016a00cc7d9SMatthew Wilcox } else { 2017a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 2018a00cc7d9SMatthew Wilcox BUG(); 2019a00cc7d9SMatthew Wilcox } 2020a00cc7d9SMatthew Wilcox return 1; 2021a00cc7d9SMatthew Wilcox } 2022a00cc7d9SMatthew Wilcox 2023a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 2024a00cc7d9SMatthew Wilcox unsigned long haddr) 2025a00cc7d9SMatthew Wilcox { 2026a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 2027a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2028a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 2029a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 2030a00cc7d9SMatthew Wilcox 2031ce9311cfSYisheng Xie count_vm_event(THP_SPLIT_PUD); 2032a00cc7d9SMatthew Wilcox 2033ec8832d0SAlistair Popple pudp_huge_clear_flush(vma, haddr, pud); 2034a00cc7d9SMatthew Wilcox } 2035a00cc7d9SMatthew Wilcox 2036a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 2037a00cc7d9SMatthew Wilcox unsigned long address) 2038a00cc7d9SMatthew Wilcox { 2039a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2040ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2041a00cc7d9SMatthew Wilcox 20427d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 20436f4f13e8SJérôme Glisse address & HPAGE_PUD_MASK, 2044ac46d4f3SJérôme Glisse (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); 2045ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2046ac46d4f3SJérôme Glisse ptl = pud_lock(vma->vm_mm, pud); 2047a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 2048a00cc7d9SMatthew Wilcox goto out; 2049ac46d4f3SJérôme Glisse __split_huge_pud_locked(vma, pud, range.start); 2050a00cc7d9SMatthew Wilcox 2051a00cc7d9SMatthew Wilcox out: 2052a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2053ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 2054a00cc7d9SMatthew Wilcox } 2055a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 2056a00cc7d9SMatthew Wilcox 2057eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2058eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2059eef1b3baSKirill A. Shutemov { 2060eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2061eef1b3baSKirill A. Shutemov pgtable_t pgtable; 206242b2af2cSDavid Hildenbrand pmd_t _pmd, old_pmd; 2063c9c1ee20SHugh Dickins unsigned long addr; 2064c9c1ee20SHugh Dickins pte_t *pte; 2065eef1b3baSKirill A. Shutemov int i; 2066eef1b3baSKirill A. Shutemov 20670f10851eSJérôme Glisse /* 20680f10851eSJérôme Glisse * Leave pmd empty until pte is filled note that it is fine to delay 20690f10851eSJérôme Glisse * notification until mmu_notifier_invalidate_range_end() as we are 20700f10851eSJérôme Glisse * replacing a zero pmd write protected page with a zero pte write 20710f10851eSJérôme Glisse * protected page. 20720f10851eSJérôme Glisse * 2073ee65728eSMike Rapoport * See Documentation/mm/mmu_notifier.rst 20740f10851eSJérôme Glisse */ 207542b2af2cSDavid Hildenbrand old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); 2076eef1b3baSKirill A. Shutemov 2077eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2078eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2079eef1b3baSKirill A. Shutemov 2080c9c1ee20SHugh Dickins pte = pte_offset_map(&_pmd, haddr); 2081c9c1ee20SHugh Dickins VM_BUG_ON(!pte); 2082c9c1ee20SHugh Dickins for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2083c9c1ee20SHugh Dickins pte_t entry; 2084c9c1ee20SHugh Dickins 2085c9c1ee20SHugh Dickins entry = pfn_pte(my_zero_pfn(addr), vma->vm_page_prot); 2086eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 208742b2af2cSDavid Hildenbrand if (pmd_uffd_wp(old_pmd)) 208842b2af2cSDavid Hildenbrand entry = pte_mkuffd_wp(entry); 2089c33c7948SRyan Roberts VM_BUG_ON(!pte_none(ptep_get(pte))); 2090c9c1ee20SHugh Dickins set_pte_at(mm, addr, pte, entry); 2091c9c1ee20SHugh Dickins pte++; 2092eef1b3baSKirill A. Shutemov } 2093c9c1ee20SHugh Dickins pte_unmap(pte - 1); 2094eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2095eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2096eef1b3baSKirill A. Shutemov } 2097eef1b3baSKirill A. Shutemov 2098eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 2099ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 2100eef1b3baSKirill A. Shutemov { 2101eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2102eef1b3baSKirill A. Shutemov struct page *page; 2103eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2104423ac9afSAneesh Kumar K.V pmd_t old_pmd, _pmd; 2105292924b2SPeter Xu bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; 21060ccf7f16SPeter Xu bool anon_exclusive = false, dirty = false; 21072ac015e2SKirill A. Shutemov unsigned long addr; 2108c9c1ee20SHugh Dickins pte_t *pte; 2109eef1b3baSKirill A. Shutemov int i; 2110eef1b3baSKirill A. Shutemov 2111eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 2112eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2113eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 211484c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) 211584c3fc4eSZi Yan && !pmd_devmap(*pmd)); 2116eef1b3baSKirill A. Shutemov 2117eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 2118eef1b3baSKirill A. Shutemov 2119d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 2120ec8832d0SAlistair Popple old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); 2121953c66c2SAneesh Kumar K.V /* 2122953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 2123953c66c2SAneesh Kumar K.V * just go ahead and zap it 2124953c66c2SAneesh Kumar K.V */ 2125953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 2126953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 21272484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) 2128d21b9e57SKirill A. Shutemov return; 212999fa8a48SHugh Dickins if (unlikely(is_pmd_migration_entry(old_pmd))) { 213099fa8a48SHugh Dickins swp_entry_t entry; 213199fa8a48SHugh Dickins 213299fa8a48SHugh Dickins entry = pmd_to_swp_entry(old_pmd); 2133af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 213499fa8a48SHugh Dickins } else { 213599fa8a48SHugh Dickins page = pmd_page(old_pmd); 213699fa8a48SHugh Dickins if (!PageDirty(page) && pmd_dirty(old_pmd)) 2137e1f1b157SHugh Dickins set_page_dirty(page); 213899fa8a48SHugh Dickins if (!PageReferenced(page) && pmd_young(old_pmd)) 2139d21b9e57SKirill A. Shutemov SetPageReferenced(page); 2140cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 2141d21b9e57SKirill A. Shutemov put_page(page); 214299fa8a48SHugh Dickins } 2143fadae295SYang Shi add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); 2144eef1b3baSKirill A. Shutemov return; 214599fa8a48SHugh Dickins } 214699fa8a48SHugh Dickins 21473b77e8c8SHugh Dickins if (is_huge_zero_pmd(*pmd)) { 21484645b9feSJérôme Glisse /* 21494645b9feSJérôme Glisse * FIXME: Do we want to invalidate secondary mmu by calling 21501af5a810SAlistair Popple * mmu_notifier_arch_invalidate_secondary_tlbs() see comments below 21511af5a810SAlistair Popple * inside __split_huge_pmd() ? 21524645b9feSJérôme Glisse * 21534645b9feSJérôme Glisse * We are going from a zero huge page write protected to zero 21544645b9feSJérôme Glisse * small page also write protected so it does not seems useful 21554645b9feSJérôme Glisse * to invalidate secondary mmu at this time. 21564645b9feSJérôme Glisse */ 2157eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 2158eef1b3baSKirill A. Shutemov } 2159eef1b3baSKirill A. Shutemov 2160423ac9afSAneesh Kumar K.V /* 2161423ac9afSAneesh Kumar K.V * Up to this point the pmd is present and huge and userland has the 2162423ac9afSAneesh Kumar K.V * whole access to the hugepage during the split (which happens in 2163423ac9afSAneesh Kumar K.V * place). If we overwrite the pmd with the not-huge version pointing 2164423ac9afSAneesh Kumar K.V * to the pte here (which of course we could if all CPUs were bug 2165423ac9afSAneesh Kumar K.V * free), userland could trigger a small page size TLB miss on the 2166423ac9afSAneesh Kumar K.V * small sized TLB while the hugepage TLB entry is still established in 2167423ac9afSAneesh Kumar K.V * the huge TLB. Some CPU doesn't like that. 216842742d9bSAlexander A. Klimov * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum 216942742d9bSAlexander A. Klimov * 383 on page 105. Intel should be safe but is also warns that it's 2170423ac9afSAneesh Kumar K.V * only safe if the permission and cache attributes of the two entries 2171423ac9afSAneesh Kumar K.V * loaded in the two TLB is identical (which should be the case here). 2172423ac9afSAneesh Kumar K.V * But it is generally safer to never allow small and huge TLB entries 2173423ac9afSAneesh Kumar K.V * for the same virtual address to be loaded simultaneously. So instead 2174423ac9afSAneesh Kumar K.V * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2175423ac9afSAneesh Kumar K.V * current pmd notpresent (atomically because here the pmd_trans_huge 2176423ac9afSAneesh Kumar K.V * must remain set at all times on the pmd until the split is complete 2177423ac9afSAneesh Kumar K.V * for this pmd), then we flush the SMP TLB and finally we write the 2178423ac9afSAneesh Kumar K.V * non-huge version of the pmd entry with pmd_populate. 2179423ac9afSAneesh Kumar K.V */ 2180423ac9afSAneesh Kumar K.V old_pmd = pmdp_invalidate(vma, haddr, pmd); 2181423ac9afSAneesh Kumar K.V 2182423ac9afSAneesh Kumar K.V pmd_migration = is_pmd_migration_entry(old_pmd); 21832e83ee1dSPeter Xu if (unlikely(pmd_migration)) { 218484c3fc4eSZi Yan swp_entry_t entry; 218584c3fc4eSZi Yan 2186423ac9afSAneesh Kumar K.V entry = pmd_to_swp_entry(old_pmd); 2187af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 21884dd845b5SAlistair Popple write = is_writable_migration_entry(entry); 21896c287605SDavid Hildenbrand if (PageAnon(page)) 21906c287605SDavid Hildenbrand anon_exclusive = is_readable_exclusive_migration_entry(entry); 21912e346877SPeter Xu young = is_migration_entry_young(entry); 21922e346877SPeter Xu dirty = is_migration_entry_dirty(entry); 21932e83ee1dSPeter Xu soft_dirty = pmd_swp_soft_dirty(old_pmd); 2194f45ec5ffSPeter Xu uffd_wp = pmd_swp_uffd_wp(old_pmd); 21952e83ee1dSPeter Xu } else { 2196423ac9afSAneesh Kumar K.V page = pmd_page(old_pmd); 21970ccf7f16SPeter Xu if (pmd_dirty(old_pmd)) { 21980ccf7f16SPeter Xu dirty = true; 2199423ac9afSAneesh Kumar K.V SetPageDirty(page); 22000ccf7f16SPeter Xu } 2201423ac9afSAneesh Kumar K.V write = pmd_write(old_pmd); 2202423ac9afSAneesh Kumar K.V young = pmd_young(old_pmd); 2203423ac9afSAneesh Kumar K.V soft_dirty = pmd_soft_dirty(old_pmd); 2204292924b2SPeter Xu uffd_wp = pmd_uffd_wp(old_pmd); 22056c287605SDavid Hildenbrand 22062e83ee1dSPeter Xu VM_BUG_ON_PAGE(!page_count(page), page); 22076c287605SDavid Hildenbrand 22086c287605SDavid Hildenbrand /* 22096c287605SDavid Hildenbrand * Without "freeze", we'll simply split the PMD, propagating the 22106c287605SDavid Hildenbrand * PageAnonExclusive() flag for each PTE by setting it for 22116c287605SDavid Hildenbrand * each subpage -- no need to (temporarily) clear. 22126c287605SDavid Hildenbrand * 22136c287605SDavid Hildenbrand * With "freeze" we want to replace mapped pages by 22146c287605SDavid Hildenbrand * migration entries right away. This is only possible if we 22156c287605SDavid Hildenbrand * managed to clear PageAnonExclusive() -- see 22166c287605SDavid Hildenbrand * set_pmd_migration_entry(). 22176c287605SDavid Hildenbrand * 22186c287605SDavid Hildenbrand * In case we cannot clear PageAnonExclusive(), split the PMD 22196c287605SDavid Hildenbrand * only and let try_to_migrate_one() fail later. 2220088b8aa5SDavid Hildenbrand * 2221088b8aa5SDavid Hildenbrand * See page_try_share_anon_rmap(): invalidate PMD first. 22226c287605SDavid Hildenbrand */ 22236c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 22246c287605SDavid Hildenbrand if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) 22256c287605SDavid Hildenbrand freeze = false; 222696d82debSHugh Dickins if (!freeze) 222796d82debSHugh Dickins page_ref_add(page, HPAGE_PMD_NR - 1); 22289d84604bSHugh Dickins } 2229eef1b3baSKirill A. Shutemov 2230423ac9afSAneesh Kumar K.V /* 2231423ac9afSAneesh Kumar K.V * Withdraw the table only after we mark the pmd entry invalid. 2232423ac9afSAneesh Kumar K.V * This's critical for some architectures (Power). 2233423ac9afSAneesh Kumar K.V */ 2234eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2235eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2236eef1b3baSKirill A. Shutemov 2237c9c1ee20SHugh Dickins pte = pte_offset_map(&_pmd, haddr); 2238c9c1ee20SHugh Dickins VM_BUG_ON(!pte); 22392ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2240c9c1ee20SHugh Dickins pte_t entry; 2241eef1b3baSKirill A. Shutemov /* 2242eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 2243eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 2244eef1b3baSKirill A. Shutemov * permissions across VMAs. 2245eef1b3baSKirill A. Shutemov */ 224684c3fc4eSZi Yan if (freeze || pmd_migration) { 2247ba988280SKirill A. Shutemov swp_entry_t swp_entry; 22484dd845b5SAlistair Popple if (write) 22494dd845b5SAlistair Popple swp_entry = make_writable_migration_entry( 22504dd845b5SAlistair Popple page_to_pfn(page + i)); 22516c287605SDavid Hildenbrand else if (anon_exclusive) 22526c287605SDavid Hildenbrand swp_entry = make_readable_exclusive_migration_entry( 22536c287605SDavid Hildenbrand page_to_pfn(page + i)); 22544dd845b5SAlistair Popple else 22554dd845b5SAlistair Popple swp_entry = make_readable_migration_entry( 22564dd845b5SAlistair Popple page_to_pfn(page + i)); 22572e346877SPeter Xu if (young) 22582e346877SPeter Xu swp_entry = make_migration_entry_young(swp_entry); 22592e346877SPeter Xu if (dirty) 22602e346877SPeter Xu swp_entry = make_migration_entry_dirty(swp_entry); 2261ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 2262804dd150SAndrea Arcangeli if (soft_dirty) 2263804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 2264f45ec5ffSPeter Xu if (uffd_wp) 2265f45ec5ffSPeter Xu entry = pte_swp_mkuffd_wp(entry); 2266ba988280SKirill A. Shutemov } else { 22676d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 22681462c52eSDavid Hildenbrand if (write) 2269161e393cSRick Edgecombe entry = pte_mkwrite(entry, vma); 22706c287605SDavid Hildenbrand if (anon_exclusive) 22716c287605SDavid Hildenbrand SetPageAnonExclusive(page + i); 2272eef1b3baSKirill A. Shutemov if (!young) 2273eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 2274e833bc50SPeter Xu /* NOTE: this may set soft-dirty too on some archs */ 2275e833bc50SPeter Xu if (dirty) 2276e833bc50SPeter Xu entry = pte_mkdirty(entry); 2277804dd150SAndrea Arcangeli if (soft_dirty) 2278804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 2279292924b2SPeter Xu if (uffd_wp) 2280292924b2SPeter Xu entry = pte_mkuffd_wp(entry); 22815ba72b4dSMiaohe Lin page_add_anon_rmap(page + i, vma, addr, RMAP_NONE); 2282ba988280SKirill A. Shutemov } 2283c33c7948SRyan Roberts VM_BUG_ON(!pte_none(ptep_get(pte))); 22842ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 2285c9c1ee20SHugh Dickins pte++; 2286eef1b3baSKirill A. Shutemov } 2287c9c1ee20SHugh Dickins pte_unmap(pte - 1); 2288eef1b3baSKirill A. Shutemov 2289cb67f428SHugh Dickins if (!pmd_migration) 2290cb67f428SHugh Dickins page_remove_rmap(page, vma, true); 229196d82debSHugh Dickins if (freeze) 229296d82debSHugh Dickins put_page(page); 2293eef1b3baSKirill A. Shutemov 2294eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2295eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2296eef1b3baSKirill A. Shutemov } 2297eef1b3baSKirill A. Shutemov 2298eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 2299af28a988SMatthew Wilcox (Oracle) unsigned long address, bool freeze, struct folio *folio) 2300eef1b3baSKirill A. Shutemov { 2301eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2302ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2303eef1b3baSKirill A. Shutemov 23047d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 23056f4f13e8SJérôme Glisse address & HPAGE_PMD_MASK, 2306ac46d4f3SJérôme Glisse (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); 2307ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2308ac46d4f3SJérôme Glisse ptl = pmd_lock(vma->vm_mm, pmd); 230933f4751eSNaoya Horiguchi 231033f4751eSNaoya Horiguchi /* 2311af28a988SMatthew Wilcox (Oracle) * If caller asks to setup a migration entry, we need a folio to check 2312af28a988SMatthew Wilcox (Oracle) * pmd against. Otherwise we can end up replacing wrong folio. 231333f4751eSNaoya Horiguchi */ 2314af28a988SMatthew Wilcox (Oracle) VM_BUG_ON(freeze && !folio); 231583a8441fSMatthew Wilcox (Oracle) VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); 231633f4751eSNaoya Horiguchi 23177f760917SDavid Hildenbrand if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || 231883a8441fSMatthew Wilcox (Oracle) is_pmd_migration_entry(*pmd)) { 2319cea33328SMiaohe Lin /* 2320cea33328SMiaohe Lin * It's safe to call pmd_page when folio is set because it's 2321cea33328SMiaohe Lin * guaranteed that pmd is present. 2322cea33328SMiaohe Lin */ 232383a8441fSMatthew Wilcox (Oracle) if (folio && folio != page_folio(pmd_page(*pmd))) 232483a8441fSMatthew Wilcox (Oracle) goto out; 2325ac46d4f3SJérôme Glisse __split_huge_pmd_locked(vma, pmd, range.start, freeze); 232683a8441fSMatthew Wilcox (Oracle) } 23277f760917SDavid Hildenbrand 2328e90309c9SKirill A. Shutemov out: 2329eef1b3baSKirill A. Shutemov spin_unlock(ptl); 2330ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 2331eef1b3baSKirill A. Shutemov } 2332eef1b3baSKirill A. Shutemov 2333fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2334af28a988SMatthew Wilcox (Oracle) bool freeze, struct folio *folio) 233594fcc585SAndrea Arcangeli { 233650722804SZach O'Keefe pmd_t *pmd = mm_find_pmd(vma->vm_mm, address); 233794fcc585SAndrea Arcangeli 233850722804SZach O'Keefe if (!pmd) 2339f72e7dcdSHugh Dickins return; 2340f72e7dcdSHugh Dickins 2341af28a988SMatthew Wilcox (Oracle) __split_huge_pmd(vma, pmd, address, freeze, folio); 234294fcc585SAndrea Arcangeli } 234394fcc585SAndrea Arcangeli 234471f9e58eSMiaohe Lin static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) 234571f9e58eSMiaohe Lin { 234671f9e58eSMiaohe Lin /* 234771f9e58eSMiaohe Lin * If the new address isn't hpage aligned and it could previously 234871f9e58eSMiaohe Lin * contain an hugepage: check if we need to split an huge pmd. 234971f9e58eSMiaohe Lin */ 235071f9e58eSMiaohe Lin if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && 235171f9e58eSMiaohe Lin range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), 235271f9e58eSMiaohe Lin ALIGN(address, HPAGE_PMD_SIZE))) 235371f9e58eSMiaohe Lin split_huge_pmd_address(vma, address, false, NULL); 235471f9e58eSMiaohe Lin } 235571f9e58eSMiaohe Lin 2356e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 235794fcc585SAndrea Arcangeli unsigned long start, 235894fcc585SAndrea Arcangeli unsigned long end, 235994fcc585SAndrea Arcangeli long adjust_next) 236094fcc585SAndrea Arcangeli { 236171f9e58eSMiaohe Lin /* Check if we need to split start first. */ 236271f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, start); 236371f9e58eSMiaohe Lin 236471f9e58eSMiaohe Lin /* Check if we need to split end next. */ 236571f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, end); 236694fcc585SAndrea Arcangeli 236794fcc585SAndrea Arcangeli /* 236868540502SMatthew Wilcox (Oracle) * If we're also updating the next vma vm_start, 236971f9e58eSMiaohe Lin * check if we need to split it. 237094fcc585SAndrea Arcangeli */ 237194fcc585SAndrea Arcangeli if (adjust_next > 0) { 237268540502SMatthew Wilcox (Oracle) struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end); 237394fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 2374f9d86a60SWei Yang nstart += adjust_next; 237571f9e58eSMiaohe Lin split_huge_pmd_if_needed(next, nstart); 237694fcc585SAndrea Arcangeli } 237794fcc585SAndrea Arcangeli } 2378e9b61f19SKirill A. Shutemov 2379684555aaSMatthew Wilcox (Oracle) static void unmap_folio(struct folio *folio) 2380e9b61f19SKirill A. Shutemov { 2381a98a2f0cSAlistair Popple enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | 2382a98a2f0cSAlistair Popple TTU_SYNC; 2383e9b61f19SKirill A. Shutemov 2384684555aaSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2385e9b61f19SKirill A. Shutemov 2386a98a2f0cSAlistair Popple /* 2387a98a2f0cSAlistair Popple * Anon pages need migration entries to preserve them, but file 2388a98a2f0cSAlistair Popple * pages can simply be left unmapped, then faulted back on demand. 2389a98a2f0cSAlistair Popple * If that is ever changed (perhaps for mlock), update remap_page(). 2390a98a2f0cSAlistair Popple */ 23914b8554c5SMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 23924b8554c5SMatthew Wilcox (Oracle) try_to_migrate(folio, ttu_flags); 2393a98a2f0cSAlistair Popple else 2394869f7ee6SMatthew Wilcox (Oracle) try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); 2395bd56086fSKirill A. Shutemov } 2396bd56086fSKirill A. Shutemov 23974eecb8b9SMatthew Wilcox (Oracle) static void remap_page(struct folio *folio, unsigned long nr) 2398e9b61f19SKirill A. Shutemov { 23994eecb8b9SMatthew Wilcox (Oracle) int i = 0; 2400ab02c252SHugh Dickins 2401684555aaSMatthew Wilcox (Oracle) /* If unmap_folio() uses try_to_migrate() on file, remove this check */ 24024eecb8b9SMatthew Wilcox (Oracle) if (!folio_test_anon(folio)) 2403ab02c252SHugh Dickins return; 24044eecb8b9SMatthew Wilcox (Oracle) for (;;) { 24054eecb8b9SMatthew Wilcox (Oracle) remove_migration_ptes(folio, folio, true); 24064eecb8b9SMatthew Wilcox (Oracle) i += folio_nr_pages(folio); 24074eecb8b9SMatthew Wilcox (Oracle) if (i >= nr) 24084eecb8b9SMatthew Wilcox (Oracle) break; 24094eecb8b9SMatthew Wilcox (Oracle) folio = folio_next(folio); 2410e9b61f19SKirill A. Shutemov } 2411ace71a19SKirill A. Shutemov } 2412e9b61f19SKirill A. Shutemov 241394866635SAlex Shi static void lru_add_page_tail(struct page *head, struct page *tail, 241488dcb9a3SAlex Shi struct lruvec *lruvec, struct list_head *list) 241588dcb9a3SAlex Shi { 241694866635SAlex Shi VM_BUG_ON_PAGE(!PageHead(head), head); 241794866635SAlex Shi VM_BUG_ON_PAGE(PageCompound(tail), head); 241894866635SAlex Shi VM_BUG_ON_PAGE(PageLRU(tail), head); 24196168d0daSAlex Shi lockdep_assert_held(&lruvec->lru_lock); 242088dcb9a3SAlex Shi 24216dbb5741SAlex Shi if (list) { 242288dcb9a3SAlex Shi /* page reclaim is reclaiming a huge page */ 24236dbb5741SAlex Shi VM_WARN_ON(PageLRU(head)); 242494866635SAlex Shi get_page(tail); 242594866635SAlex Shi list_add_tail(&tail->lru, list); 242688dcb9a3SAlex Shi } else { 24276dbb5741SAlex Shi /* head is still on lru (and we have it frozen) */ 24286dbb5741SAlex Shi VM_WARN_ON(!PageLRU(head)); 242907ca7606SHugh Dickins if (PageUnevictable(tail)) 243007ca7606SHugh Dickins tail->mlock_count = 0; 243107ca7606SHugh Dickins else 24326dbb5741SAlex Shi list_add_tail(&tail->lru, &head->lru); 243307ca7606SHugh Dickins SetPageLRU(tail); 243488dcb9a3SAlex Shi } 243588dcb9a3SAlex Shi } 243688dcb9a3SAlex Shi 243707e09c48SDavid Hildenbrand static void __split_huge_page_tail(struct folio *folio, int tail, 2438e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2439e9b61f19SKirill A. Shutemov { 244007e09c48SDavid Hildenbrand struct page *head = &folio->page; 2441e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 244207e09c48SDavid Hildenbrand /* 244307e09c48SDavid Hildenbrand * Careful: new_folio is not a "real" folio before we cleared PageTail. 244407e09c48SDavid Hildenbrand * Don't pass it around before clear_compound_head(). 244507e09c48SDavid Hildenbrand */ 244607e09c48SDavid Hildenbrand struct folio *new_folio = (struct folio *)page_tail; 2447e9b61f19SKirill A. Shutemov 24488df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2449e9b61f19SKirill A. Shutemov 2450e9b61f19SKirill A. Shutemov /* 2451605ca5edSKonstantin Khlebnikov * Clone page flags before unfreezing refcount. 2452605ca5edSKonstantin Khlebnikov * 2453605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow flags change, 24548958b249SHaitao Shi * for example lock_page() which set PG_waiters. 24556c287605SDavid Hildenbrand * 24566c287605SDavid Hildenbrand * Note that for mapped sub-pages of an anonymous THP, 2457684555aaSMatthew Wilcox (Oracle) * PG_anon_exclusive has been cleared in unmap_folio() and is stored in 24586c287605SDavid Hildenbrand * the migration entry instead from where remap_page() will restore it. 24596c287605SDavid Hildenbrand * We can still have PG_anon_exclusive set on effectively unmapped and 24606c287605SDavid Hildenbrand * unreferenced sub-pages of an anonymous THP: we can simply drop 24616c287605SDavid Hildenbrand * PG_anon_exclusive (-> PG_mappedtodisk) for these here. 2462e9b61f19SKirill A. Shutemov */ 2463e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2464e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2465e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2466e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 246738d8b4e6SHuang Ying (1L << PG_swapcache) | 2468e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2469e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2470e9b61f19SKirill A. Shutemov (1L << PG_active) | 24711899ad18SJohannes Weiner (1L << PG_workingset) | 2472e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2473b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 2474b0284cd2SCatalin Marinas #ifdef CONFIG_ARCH_USES_PG_ARCH_X 247572e6afa0SCatalin Marinas (1L << PG_arch_2) | 2476ef6458b1SPeter Collingbourne (1L << PG_arch_3) | 247772e6afa0SCatalin Marinas #endif 2478ec1c86b2SYu Zhao (1L << PG_dirty) | 2479ec1c86b2SYu Zhao LRU_GEN_MASK | LRU_REFS_MASK)); 2480e9b61f19SKirill A. Shutemov 2481cb67f428SHugh Dickins /* ->mapping in first and second tail page is replaced by other uses */ 2482173d9d9fSHugh Dickins VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2483173d9d9fSHugh Dickins page_tail); 2484173d9d9fSHugh Dickins page_tail->mapping = head->mapping; 2485173d9d9fSHugh Dickins page_tail->index = head->index + tail; 248671e2d666SMel Gorman 248771e2d666SMel Gorman /* 2488cfeed8ffSDavid Hildenbrand * page->private should not be set in tail pages. Fix up and warn once 2489cfeed8ffSDavid Hildenbrand * if private is unexpectedly set. 249071e2d666SMel Gorman */ 2491cfeed8ffSDavid Hildenbrand if (unlikely(page_tail->private)) { 2492cfeed8ffSDavid Hildenbrand VM_WARN_ON_ONCE_PAGE(true, page_tail); 2493b653db77SMatthew Wilcox (Oracle) page_tail->private = 0; 249471e2d666SMel Gorman } 249507e09c48SDavid Hildenbrand if (folio_test_swapcache(folio)) 249607e09c48SDavid Hildenbrand new_folio->swap.val = folio->swap.val + tail; 2497173d9d9fSHugh Dickins 2498605ca5edSKonstantin Khlebnikov /* Page flags must be visible before we make the page non-compound. */ 2499e9b61f19SKirill A. Shutemov smp_wmb(); 2500e9b61f19SKirill A. Shutemov 2501605ca5edSKonstantin Khlebnikov /* 2502605ca5edSKonstantin Khlebnikov * Clear PageTail before unfreezing page refcount. 2503605ca5edSKonstantin Khlebnikov * 2504605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow put_page() 2505605ca5edSKonstantin Khlebnikov * which needs correct compound_head(). 2506605ca5edSKonstantin Khlebnikov */ 2507e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2508e9b61f19SKirill A. Shutemov 2509605ca5edSKonstantin Khlebnikov /* Finally unfreeze refcount. Additional reference from page cache. */ 2510605ca5edSKonstantin Khlebnikov page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || 2511605ca5edSKonstantin Khlebnikov PageSwapCache(head))); 2512605ca5edSKonstantin Khlebnikov 2513e9b61f19SKirill A. Shutemov if (page_is_young(head)) 2514e9b61f19SKirill A. Shutemov set_page_young(page_tail); 2515e9b61f19SKirill A. Shutemov if (page_is_idle(head)) 2516e9b61f19SKirill A. Shutemov set_page_idle(page_tail); 2517e9b61f19SKirill A. Shutemov 2518c8253011SKefeng Wang folio_xchg_last_cpupid(new_folio, folio_last_cpupid(folio)); 251994723aafSMichal Hocko 252094723aafSMichal Hocko /* 252194723aafSMichal Hocko * always add to the tail because some iterators expect new 252294723aafSMichal Hocko * pages to show after the currently processed elements - e.g. 252394723aafSMichal Hocko * migrate_pages 252494723aafSMichal Hocko */ 2525e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2526e9b61f19SKirill A. Shutemov } 2527e9b61f19SKirill A. Shutemov 2528baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2529b6769834SAlex Shi pgoff_t end) 2530e9b61f19SKirill A. Shutemov { 2531e809c3feSMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2532e809c3feSMatthew Wilcox (Oracle) struct page *head = &folio->page; 2533e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 25344101196bSMatthew Wilcox (Oracle) struct address_space *swap_cache = NULL; 25354101196bSMatthew Wilcox (Oracle) unsigned long offset = 0; 25368cce5475SKirill A. Shutemov unsigned int nr = thp_nr_pages(head); 2537509f0069SHugh Dickins int i, nr_dropped = 0; 2538e9b61f19SKirill A. Shutemov 2539e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2540be6c8982SZhou Guanghui split_page_memcg(head, nr); 2541e9b61f19SKirill A. Shutemov 254207e09c48SDavid Hildenbrand if (folio_test_anon(folio) && folio_test_swapcache(folio)) { 254307e09c48SDavid Hildenbrand offset = swp_offset(folio->swap); 254407e09c48SDavid Hildenbrand swap_cache = swap_address_space(folio->swap); 25454101196bSMatthew Wilcox (Oracle) xa_lock(&swap_cache->i_pages); 25464101196bSMatthew Wilcox (Oracle) } 25474101196bSMatthew Wilcox (Oracle) 2548f0953a1bSIngo Molnar /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ 2549e809c3feSMatthew Wilcox (Oracle) lruvec = folio_lruvec_lock(folio); 2550b6769834SAlex Shi 2551eac96c3eSYang Shi ClearPageHasHWPoisoned(head); 2552eac96c3eSYang Shi 25538cce5475SKirill A. Shutemov for (i = nr - 1; i >= 1; i--) { 255407e09c48SDavid Hildenbrand __split_huge_page_tail(folio, i, lruvec, list); 2555d144bf62SHugh Dickins /* Some pages can be beyond EOF: drop them from page cache */ 2556baa355fdSKirill A. Shutemov if (head[i].index >= end) { 2557fb5c2029SMatthew Wilcox (Oracle) struct folio *tail = page_folio(head + i); 2558fb5c2029SMatthew Wilcox (Oracle) 2559d144bf62SHugh Dickins if (shmem_mapping(head->mapping)) 2560509f0069SHugh Dickins nr_dropped++; 2561fb5c2029SMatthew Wilcox (Oracle) else if (folio_test_clear_dirty(tail)) 2562fb5c2029SMatthew Wilcox (Oracle) folio_account_cleaned(tail, 2563fb5c2029SMatthew Wilcox (Oracle) inode_to_wb(folio->mapping->host)); 2564fb5c2029SMatthew Wilcox (Oracle) __filemap_remove_folio(tail, NULL); 2565fb5c2029SMatthew Wilcox (Oracle) folio_put(tail); 25664101196bSMatthew Wilcox (Oracle) } else if (!PageAnon(page)) { 25674101196bSMatthew Wilcox (Oracle) __xa_store(&head->mapping->i_pages, head[i].index, 25684101196bSMatthew Wilcox (Oracle) head + i, 0); 25694101196bSMatthew Wilcox (Oracle) } else if (swap_cache) { 25704101196bSMatthew Wilcox (Oracle) __xa_store(&swap_cache->i_pages, offset + i, 25714101196bSMatthew Wilcox (Oracle) head + i, 0); 2572baa355fdSKirill A. Shutemov } 2573baa355fdSKirill A. Shutemov } 2574e9b61f19SKirill A. Shutemov 2575e9b61f19SKirill A. Shutemov ClearPageCompound(head); 25766168d0daSAlex Shi unlock_page_lruvec(lruvec); 2577b6769834SAlex Shi /* Caller disabled irqs, so they are still disabled here */ 2578f7da677bSVlastimil Babka 25798cce5475SKirill A. Shutemov split_page_owner(head, nr); 2580f7da677bSVlastimil Babka 2581baa355fdSKirill A. Shutemov /* See comment in __split_huge_page_tail() */ 2582baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2583aa5dc07fSMatthew Wilcox /* Additional pin to swap cache */ 25844101196bSMatthew Wilcox (Oracle) if (PageSwapCache(head)) { 258538d8b4e6SHuang Ying page_ref_add(head, 2); 25864101196bSMatthew Wilcox (Oracle) xa_unlock(&swap_cache->i_pages); 25874101196bSMatthew Wilcox (Oracle) } else { 2588baa355fdSKirill A. Shutemov page_ref_inc(head); 25894101196bSMatthew Wilcox (Oracle) } 2590baa355fdSKirill A. Shutemov } else { 2591aa5dc07fSMatthew Wilcox /* Additional pin to page cache */ 2592baa355fdSKirill A. Shutemov page_ref_add(head, 2); 2593b93b0163SMatthew Wilcox xa_unlock(&head->mapping->i_pages); 2594baa355fdSKirill A. Shutemov } 2595b6769834SAlex Shi local_irq_enable(); 2596e9b61f19SKirill A. Shutemov 2597509f0069SHugh Dickins if (nr_dropped) 2598509f0069SHugh Dickins shmem_uncharge(head->mapping->host, nr_dropped); 25994eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, nr); 2600e9b61f19SKirill A. Shutemov 260107e09c48SDavid Hildenbrand if (folio_test_swapcache(folio)) 260207e09c48SDavid Hildenbrand split_swap_cluster(folio->swap); 2603c4f9c701SHuang Ying 26048cce5475SKirill A. Shutemov for (i = 0; i < nr; i++) { 2605e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2606e9b61f19SKirill A. Shutemov if (subpage == page) 2607e9b61f19SKirill A. Shutemov continue; 2608e9b61f19SKirill A. Shutemov unlock_page(subpage); 2609e9b61f19SKirill A. Shutemov 2610e9b61f19SKirill A. Shutemov /* 2611e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2612e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2613e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2614e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2615e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2616e9b61f19SKirill A. Shutemov */ 26170b175468SMiaohe Lin free_page_and_swap_cache(subpage); 2618e9b61f19SKirill A. Shutemov } 2619e9b61f19SKirill A. Shutemov } 2620e9b61f19SKirill A. Shutemov 2621b8f593cdSHuang Ying /* Racy check whether the huge page can be split */ 2622d4b4084aSMatthew Wilcox (Oracle) bool can_split_folio(struct folio *folio, int *pextra_pins) 2623b8f593cdSHuang Ying { 2624b8f593cdSHuang Ying int extra_pins; 2625b8f593cdSHuang Ying 2626aa5dc07fSMatthew Wilcox /* Additional pins from page cache */ 2627d4b4084aSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 2628d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_test_swapcache(folio) ? 2629d4b4084aSMatthew Wilcox (Oracle) folio_nr_pages(folio) : 0; 2630b8f593cdSHuang Ying else 2631d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_nr_pages(folio); 2632b8f593cdSHuang Ying if (pextra_pins) 2633b8f593cdSHuang Ying *pextra_pins = extra_pins; 2634d4b4084aSMatthew Wilcox (Oracle) return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; 2635b8f593cdSHuang Ying } 2636b8f593cdSHuang Ying 26376d0a07edSAndrea Arcangeli /* 2638e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2639e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2640e9b61f19SKirill A. Shutemov * 2641e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2642e9b61f19SKirill A. Shutemov * The huge page must be locked. 2643e9b61f19SKirill A. Shutemov * 2644e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2645e9b61f19SKirill A. Shutemov * 2646e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2647e9b61f19SKirill A. Shutemov * the hugepage. 2648e9b61f19SKirill A. Shutemov * 2649e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2650e9b61f19SKirill A. Shutemov * they are not mapped. 2651e9b61f19SKirill A. Shutemov * 2652e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2653e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2654e9b61f19SKirill A. Shutemov * us. 2655e9b61f19SKirill A. Shutemov */ 2656e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2657e9b61f19SKirill A. Shutemov { 26584eecb8b9SMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2659f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *ds_queue = get_deferred_split_queue(folio); 26603e9a13daSMatthew Wilcox (Oracle) XA_STATE(xas, &folio->mapping->i_pages, folio->index); 2661baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2662baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2663504e070dSYang Shi int extra_pins, ret; 2664006d3ff2SHugh Dickins pgoff_t end; 2665478d134eSXu Yu bool is_hzp; 2666e9b61f19SKirill A. Shutemov 26673e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); 26683e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2669e9b61f19SKirill A. Shutemov 26703e9a13daSMatthew Wilcox (Oracle) is_hzp = is_huge_zero_page(&folio->page); 26714737edbbSNaoya Horiguchi if (is_hzp) { 26724737edbbSNaoya Horiguchi pr_warn_ratelimited("Called split_huge_page for huge zero page\n"); 2673478d134eSXu Yu return -EBUSY; 26744737edbbSNaoya Horiguchi } 2675478d134eSXu Yu 26763e9a13daSMatthew Wilcox (Oracle) if (folio_test_writeback(folio)) 267759807685SHuang Ying return -EBUSY; 267859807685SHuang Ying 26793e9a13daSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) { 2680e9b61f19SKirill A. Shutemov /* 2681c1e8d7c6SMichel Lespinasse * The caller does not necessarily hold an mmap_lock that would 2682baa355fdSKirill A. Shutemov * prevent the anon_vma disappearing so we first we take a 2683baa355fdSKirill A. Shutemov * reference to it and then lock the anon_vma for write. This 26842f031c6fSMatthew Wilcox (Oracle) * is similar to folio_lock_anon_vma_read except the write lock 2685baa355fdSKirill A. Shutemov * is taken to serialise against parallel split or collapse 2686baa355fdSKirill A. Shutemov * operations. 2687e9b61f19SKirill A. Shutemov */ 268829eea9b5SMatthew Wilcox (Oracle) anon_vma = folio_get_anon_vma(folio); 2689e9b61f19SKirill A. Shutemov if (!anon_vma) { 2690e9b61f19SKirill A. Shutemov ret = -EBUSY; 2691e9b61f19SKirill A. Shutemov goto out; 2692e9b61f19SKirill A. Shutemov } 2693006d3ff2SHugh Dickins end = -1; 2694baa355fdSKirill A. Shutemov mapping = NULL; 2695e9b61f19SKirill A. Shutemov anon_vma_lock_write(anon_vma); 2696baa355fdSKirill A. Shutemov } else { 26976a3edd29SYin Fengwei gfp_t gfp; 26986a3edd29SYin Fengwei 26993e9a13daSMatthew Wilcox (Oracle) mapping = folio->mapping; 2700baa355fdSKirill A. Shutemov 2701baa355fdSKirill A. Shutemov /* Truncated ? */ 2702baa355fdSKirill A. Shutemov if (!mapping) { 2703baa355fdSKirill A. Shutemov ret = -EBUSY; 2704baa355fdSKirill A. Shutemov goto out; 2705baa355fdSKirill A. Shutemov } 2706baa355fdSKirill A. Shutemov 27076a3edd29SYin Fengwei gfp = current_gfp_context(mapping_gfp_mask(mapping) & 27086a3edd29SYin Fengwei GFP_RECLAIM_MASK); 27096a3edd29SYin Fengwei 27100201ebf2SDavid Howells if (!filemap_release_folio(folio, gfp)) { 27116a3edd29SYin Fengwei ret = -EBUSY; 27126a3edd29SYin Fengwei goto out; 27136a3edd29SYin Fengwei } 27146a3edd29SYin Fengwei 27153e9a13daSMatthew Wilcox (Oracle) xas_split_alloc(&xas, folio, folio_order(folio), gfp); 27166b24ca4aSMatthew Wilcox (Oracle) if (xas_error(&xas)) { 27176b24ca4aSMatthew Wilcox (Oracle) ret = xas_error(&xas); 27186b24ca4aSMatthew Wilcox (Oracle) goto out; 27196b24ca4aSMatthew Wilcox (Oracle) } 27206b24ca4aSMatthew Wilcox (Oracle) 2721baa355fdSKirill A. Shutemov anon_vma = NULL; 2722baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 2723006d3ff2SHugh Dickins 2724006d3ff2SHugh Dickins /* 2725006d3ff2SHugh Dickins *__split_huge_page() may need to trim off pages beyond EOF: 2726006d3ff2SHugh Dickins * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, 2727006d3ff2SHugh Dickins * which cannot be nested inside the page tree lock. So note 2728006d3ff2SHugh Dickins * end now: i_size itself may be changed at any moment, but 27293e9a13daSMatthew Wilcox (Oracle) * folio lock is good enough to serialize the trimming. 2730006d3ff2SHugh Dickins */ 2731006d3ff2SHugh Dickins end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); 2732d144bf62SHugh Dickins if (shmem_mapping(mapping)) 2733d144bf62SHugh Dickins end = shmem_fallocend(mapping->host, end); 2734baa355fdSKirill A. Shutemov } 2735e9b61f19SKirill A. Shutemov 2736e9b61f19SKirill A. Shutemov /* 2737684555aaSMatthew Wilcox (Oracle) * Racy check if we can split the page, before unmap_folio() will 2738e9b61f19SKirill A. Shutemov * split PMDs 2739e9b61f19SKirill A. Shutemov */ 2740d4b4084aSMatthew Wilcox (Oracle) if (!can_split_folio(folio, &extra_pins)) { 2741fd4a7ac3SBaolin Wang ret = -EAGAIN; 2742e9b61f19SKirill A. Shutemov goto out_unlock; 2743e9b61f19SKirill A. Shutemov } 2744e9b61f19SKirill A. Shutemov 2745684555aaSMatthew Wilcox (Oracle) unmap_folio(folio); 2746e9b61f19SKirill A. Shutemov 2747b6769834SAlex Shi /* block interrupt reentry in xa_lock and spinlock */ 2748b6769834SAlex Shi local_irq_disable(); 2749baa355fdSKirill A. Shutemov if (mapping) { 2750baa355fdSKirill A. Shutemov /* 27513e9a13daSMatthew Wilcox (Oracle) * Check if the folio is present in page cache. 27523e9a13daSMatthew Wilcox (Oracle) * We assume all tail are present too, if folio is there. 2753baa355fdSKirill A. Shutemov */ 27546b24ca4aSMatthew Wilcox (Oracle) xas_lock(&xas); 27556b24ca4aSMatthew Wilcox (Oracle) xas_reset(&xas); 27563e9a13daSMatthew Wilcox (Oracle) if (xas_load(&xas) != folio) 2757baa355fdSKirill A. Shutemov goto fail; 2758baa355fdSKirill A. Shutemov } 2759baa355fdSKirill A. Shutemov 27600139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 2761364c1eebSYang Shi spin_lock(&ds_queue->split_queue_lock); 27623e9a13daSMatthew Wilcox (Oracle) if (folio_ref_freeze(folio, 1 + extra_pins)) { 27634375a553SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) { 2764364c1eebSYang Shi ds_queue->split_queue_len--; 27654375a553SMatthew Wilcox (Oracle) list_del(&folio->_deferred_list); 27669a982250SKirill A. Shutemov } 2767afb97172SWei Yang spin_unlock(&ds_queue->split_queue_lock); 276806d3eff6SKirill A. Shutemov if (mapping) { 27693e9a13daSMatthew Wilcox (Oracle) int nr = folio_nr_pages(folio); 2770bf9eceadSMuchun Song 27713e9a13daSMatthew Wilcox (Oracle) xas_split(&xas, folio, folio_order(folio)); 2772a48d5bdcSStefan Roesch if (folio_test_pmd_mappable(folio)) { 27733e9a13daSMatthew Wilcox (Oracle) if (folio_test_swapbacked(folio)) { 2774a48d5bdcSStefan Roesch __lruvec_stat_mod_folio(folio, 2775a48d5bdcSStefan Roesch NR_SHMEM_THPS, -nr); 27761ca7554dSMarek Szyprowski } else { 2777a48d5bdcSStefan Roesch __lruvec_stat_mod_folio(folio, 2778a48d5bdcSStefan Roesch NR_FILE_THPS, -nr); 27791ca7554dSMarek Szyprowski filemap_nr_thps_dec(mapping); 27801ca7554dSMarek Szyprowski } 278106d3eff6SKirill A. Shutemov } 2782a48d5bdcSStefan Roesch } 278306d3eff6SKirill A. Shutemov 2784b6769834SAlex Shi __split_huge_page(page, list, end); 2785e9b61f19SKirill A. Shutemov ret = 0; 2786baa355fdSKirill A. Shutemov } else { 2787364c1eebSYang Shi spin_unlock(&ds_queue->split_queue_lock); 2788504e070dSYang Shi fail: 2789504e070dSYang Shi if (mapping) 27906b24ca4aSMatthew Wilcox (Oracle) xas_unlock(&xas); 2791b6769834SAlex Shi local_irq_enable(); 27924eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, folio_nr_pages(folio)); 2793fd4a7ac3SBaolin Wang ret = -EAGAIN; 2794e9b61f19SKirill A. Shutemov } 2795e9b61f19SKirill A. Shutemov 2796e9b61f19SKirill A. Shutemov out_unlock: 2797baa355fdSKirill A. Shutemov if (anon_vma) { 2798e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 2799e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 2800baa355fdSKirill A. Shutemov } 2801baa355fdSKirill A. Shutemov if (mapping) 2802baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 2803e9b61f19SKirill A. Shutemov out: 280469a37a8bSMatthew Wilcox (Oracle) xas_destroy(&xas); 2805e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 2806e9b61f19SKirill A. Shutemov return ret; 2807e9b61f19SKirill A. Shutemov } 28089a982250SKirill A. Shutemov 28098dc4a8f1SMatthew Wilcox (Oracle) void folio_undo_large_rmappable(struct folio *folio) 28109a982250SKirill A. Shutemov { 28118dc4a8f1SMatthew Wilcox (Oracle) struct deferred_split *ds_queue; 28129a982250SKirill A. Shutemov unsigned long flags; 28139a982250SKirill A. Shutemov 2814deedad80SYin Fengwei /* 2815deedad80SYin Fengwei * At this point, there is no one trying to add the folio to 2816deedad80SYin Fengwei * deferred_list. If folio is not in deferred_list, it's safe 2817deedad80SYin Fengwei * to check without acquiring the split_queue_lock. 2818deedad80SYin Fengwei */ 28198dc4a8f1SMatthew Wilcox (Oracle) if (data_race(list_empty(&folio->_deferred_list))) 28208dc4a8f1SMatthew Wilcox (Oracle) return; 28218dc4a8f1SMatthew Wilcox (Oracle) 28228dc4a8f1SMatthew Wilcox (Oracle) ds_queue = get_deferred_split_queue(folio); 2823364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28248991de90SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) { 2825364c1eebSYang Shi ds_queue->split_queue_len--; 2826*9bcef597SBaolin Wang list_del_init(&folio->_deferred_list); 28279a982250SKirill A. Shutemov } 2828364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 2829deedad80SYin Fengwei } 28309a982250SKirill A. Shutemov 2831f158ed61SMatthew Wilcox (Oracle) void deferred_split_folio(struct folio *folio) 28329a982250SKirill A. Shutemov { 2833f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *ds_queue = get_deferred_split_queue(folio); 283487eaceb3SYang Shi #ifdef CONFIG_MEMCG 28358991de90SMatthew Wilcox (Oracle) struct mem_cgroup *memcg = folio_memcg(folio); 283687eaceb3SYang Shi #endif 28379a982250SKirill A. Shutemov unsigned long flags; 28389a982250SKirill A. Shutemov 28398991de90SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); 28409a982250SKirill A. Shutemov 284187eaceb3SYang Shi /* 284287eaceb3SYang Shi * The try_to_unmap() in page reclaim path might reach here too, 284387eaceb3SYang Shi * this may cause a race condition to corrupt deferred split queue. 28448991de90SMatthew Wilcox (Oracle) * And, if page reclaim is already handling the same folio, it is 284587eaceb3SYang Shi * unnecessary to handle it again in shrinker. 284687eaceb3SYang Shi * 28478991de90SMatthew Wilcox (Oracle) * Check the swapcache flag to determine if the folio is being 28488991de90SMatthew Wilcox (Oracle) * handled by page reclaim since THP swap would add the folio into 284987eaceb3SYang Shi * swap cache before calling try_to_unmap(). 285087eaceb3SYang Shi */ 28518991de90SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 285287eaceb3SYang Shi return; 285387eaceb3SYang Shi 28548991de90SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) 28559a982250SKirill A. Shutemov return; 28569a982250SKirill A. Shutemov 2857364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28588991de90SMatthew Wilcox (Oracle) if (list_empty(&folio->_deferred_list)) { 2859f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 28608991de90SMatthew Wilcox (Oracle) list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); 2861364c1eebSYang Shi ds_queue->split_queue_len++; 286287eaceb3SYang Shi #ifdef CONFIG_MEMCG 286387eaceb3SYang Shi if (memcg) 28648991de90SMatthew Wilcox (Oracle) set_shrinker_bit(memcg, folio_nid(folio), 286554d91729SQi Zheng deferred_split_shrinker->id); 286687eaceb3SYang Shi #endif 28679a982250SKirill A. Shutemov } 2868364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28699a982250SKirill A. Shutemov } 28709a982250SKirill A. Shutemov 28719a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 28729a982250SKirill A. Shutemov struct shrink_control *sc) 28739a982250SKirill A. Shutemov { 2874a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2875364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 287687eaceb3SYang Shi 287787eaceb3SYang Shi #ifdef CONFIG_MEMCG 287887eaceb3SYang Shi if (sc->memcg) 287987eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 288087eaceb3SYang Shi #endif 2881364c1eebSYang Shi return READ_ONCE(ds_queue->split_queue_len); 28829a982250SKirill A. Shutemov } 28839a982250SKirill A. Shutemov 28849a982250SKirill A. Shutemov static unsigned long deferred_split_scan(struct shrinker *shrink, 28859a982250SKirill A. Shutemov struct shrink_control *sc) 28869a982250SKirill A. Shutemov { 2887a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2888364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 28899a982250SKirill A. Shutemov unsigned long flags; 28904375a553SMatthew Wilcox (Oracle) LIST_HEAD(list); 28914375a553SMatthew Wilcox (Oracle) struct folio *folio, *next; 28929a982250SKirill A. Shutemov int split = 0; 28939a982250SKirill A. Shutemov 289487eaceb3SYang Shi #ifdef CONFIG_MEMCG 289587eaceb3SYang Shi if (sc->memcg) 289687eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 289787eaceb3SYang Shi #endif 289887eaceb3SYang Shi 2899364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 29009a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 29014375a553SMatthew Wilcox (Oracle) list_for_each_entry_safe(folio, next, &ds_queue->split_queue, 29024375a553SMatthew Wilcox (Oracle) _deferred_list) { 29034375a553SMatthew Wilcox (Oracle) if (folio_try_get(folio)) { 29044375a553SMatthew Wilcox (Oracle) list_move(&folio->_deferred_list, &list); 2905e3ae1953SKirill A. Shutemov } else { 29064375a553SMatthew Wilcox (Oracle) /* We lost race with folio_put() */ 29074375a553SMatthew Wilcox (Oracle) list_del_init(&folio->_deferred_list); 2908364c1eebSYang Shi ds_queue->split_queue_len--; 29099a982250SKirill A. Shutemov } 2910e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 2911e3ae1953SKirill A. Shutemov break; 29129a982250SKirill A. Shutemov } 2913364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 29149a982250SKirill A. Shutemov 29154375a553SMatthew Wilcox (Oracle) list_for_each_entry_safe(folio, next, &list, _deferred_list) { 29164375a553SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 2917fa41b900SKirill A. Shutemov goto next; 29189a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 29194375a553SMatthew Wilcox (Oracle) if (!split_folio(folio)) 29209a982250SKirill A. Shutemov split++; 29214375a553SMatthew Wilcox (Oracle) folio_unlock(folio); 2922fa41b900SKirill A. Shutemov next: 29234375a553SMatthew Wilcox (Oracle) folio_put(folio); 29249a982250SKirill A. Shutemov } 29259a982250SKirill A. Shutemov 2926364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 2927364c1eebSYang Shi list_splice_tail(&list, &ds_queue->split_queue); 2928364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 29299a982250SKirill A. Shutemov 2930cb8d68ecSKirill A. Shutemov /* 2931cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 2932cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 2933cb8d68ecSKirill A. Shutemov */ 2934364c1eebSYang Shi if (!split && list_empty(&ds_queue->split_queue)) 2935cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 2936cb8d68ecSKirill A. Shutemov return split; 29379a982250SKirill A. Shutemov } 29389a982250SKirill A. Shutemov 293949071d43SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 2940fa6c0231SZi Yan static void split_huge_pages_all(void) 294149071d43SKirill A. Shutemov { 294249071d43SKirill A. Shutemov struct zone *zone; 294349071d43SKirill A. Shutemov struct page *page; 2944630e7c5eSKefeng Wang struct folio *folio; 294549071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 294649071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 294749071d43SKirill A. Shutemov 2948fa6c0231SZi Yan pr_debug("Split all THPs\n"); 2949a17206daSMiaohe Lin for_each_zone(zone) { 2950a17206daSMiaohe Lin if (!managed_zone(zone)) 2951a17206daSMiaohe Lin continue; 295249071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 295349071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 2954a17206daSMiaohe Lin int nr_pages; 295549071d43SKirill A. Shutemov 29562b7aa91bSNaoya Horiguchi page = pfn_to_online_page(pfn); 2957630e7c5eSKefeng Wang if (!page || PageTail(page)) 2958630e7c5eSKefeng Wang continue; 2959630e7c5eSKefeng Wang folio = page_folio(page); 2960630e7c5eSKefeng Wang if (!folio_try_get(folio)) 296149071d43SKirill A. Shutemov continue; 296249071d43SKirill A. Shutemov 2963630e7c5eSKefeng Wang if (unlikely(page_folio(page) != folio)) 296449071d43SKirill A. Shutemov goto next; 296549071d43SKirill A. Shutemov 2966630e7c5eSKefeng Wang if (zone != folio_zone(folio)) 2967630e7c5eSKefeng Wang goto next; 2968630e7c5eSKefeng Wang 2969630e7c5eSKefeng Wang if (!folio_test_large(folio) 2970630e7c5eSKefeng Wang || folio_test_hugetlb(folio) 2971630e7c5eSKefeng Wang || !folio_test_lru(folio)) 297249071d43SKirill A. Shutemov goto next; 297349071d43SKirill A. Shutemov 297449071d43SKirill A. Shutemov total++; 2975630e7c5eSKefeng Wang folio_lock(folio); 2976630e7c5eSKefeng Wang nr_pages = folio_nr_pages(folio); 2977630e7c5eSKefeng Wang if (!split_folio(folio)) 297849071d43SKirill A. Shutemov split++; 2979a17206daSMiaohe Lin pfn += nr_pages - 1; 2980630e7c5eSKefeng Wang folio_unlock(folio); 298149071d43SKirill A. Shutemov next: 2982630e7c5eSKefeng Wang folio_put(folio); 2983fa6c0231SZi Yan cond_resched(); 298449071d43SKirill A. Shutemov } 298549071d43SKirill A. Shutemov } 298649071d43SKirill A. Shutemov 2987fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 298849071d43SKirill A. Shutemov } 2989fa6c0231SZi Yan 2990fa6c0231SZi Yan static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) 2991fa6c0231SZi Yan { 2992fa6c0231SZi Yan return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || 2993fa6c0231SZi Yan is_vm_hugetlb_page(vma); 2994fa6c0231SZi Yan } 2995fa6c0231SZi Yan 2996fa6c0231SZi Yan static int split_huge_pages_pid(int pid, unsigned long vaddr_start, 2997fa6c0231SZi Yan unsigned long vaddr_end) 2998fa6c0231SZi Yan { 2999fa6c0231SZi Yan int ret = 0; 3000fa6c0231SZi Yan struct task_struct *task; 3001fa6c0231SZi Yan struct mm_struct *mm; 3002fa6c0231SZi Yan unsigned long total = 0, split = 0; 3003fa6c0231SZi Yan unsigned long addr; 3004fa6c0231SZi Yan 3005fa6c0231SZi Yan vaddr_start &= PAGE_MASK; 3006fa6c0231SZi Yan vaddr_end &= PAGE_MASK; 3007fa6c0231SZi Yan 3008fa6c0231SZi Yan /* Find the task_struct from pid */ 3009fa6c0231SZi Yan rcu_read_lock(); 3010fa6c0231SZi Yan task = find_task_by_vpid(pid); 3011fa6c0231SZi Yan if (!task) { 3012fa6c0231SZi Yan rcu_read_unlock(); 3013fa6c0231SZi Yan ret = -ESRCH; 3014fa6c0231SZi Yan goto out; 3015fa6c0231SZi Yan } 3016fa6c0231SZi Yan get_task_struct(task); 3017fa6c0231SZi Yan rcu_read_unlock(); 3018fa6c0231SZi Yan 3019fa6c0231SZi Yan /* Find the mm_struct */ 3020fa6c0231SZi Yan mm = get_task_mm(task); 3021fa6c0231SZi Yan put_task_struct(task); 3022fa6c0231SZi Yan 3023fa6c0231SZi Yan if (!mm) { 3024fa6c0231SZi Yan ret = -EINVAL; 3025fa6c0231SZi Yan goto out; 3026fa6c0231SZi Yan } 3027fa6c0231SZi Yan 3028fa6c0231SZi Yan pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", 3029fa6c0231SZi Yan pid, vaddr_start, vaddr_end); 3030fa6c0231SZi Yan 3031fa6c0231SZi Yan mmap_read_lock(mm); 3032fa6c0231SZi Yan /* 3033fa6c0231SZi Yan * always increase addr by PAGE_SIZE, since we could have a PTE page 3034fa6c0231SZi Yan * table filled with PTE-mapped THPs, each of which is distinct. 3035fa6c0231SZi Yan */ 3036fa6c0231SZi Yan for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { 303774ba2b38SMiaohe Lin struct vm_area_struct *vma = vma_lookup(mm, addr); 3038fa6c0231SZi Yan struct page *page; 3039a644b0abSMatthew Wilcox (Oracle) struct folio *folio; 3040fa6c0231SZi Yan 304174ba2b38SMiaohe Lin if (!vma) 3042fa6c0231SZi Yan break; 3043fa6c0231SZi Yan 3044fa6c0231SZi Yan /* skip special VMA and hugetlb VMA */ 3045fa6c0231SZi Yan if (vma_not_suitable_for_thp_split(vma)) { 3046fa6c0231SZi Yan addr = vma->vm_end; 3047fa6c0231SZi Yan continue; 3048fa6c0231SZi Yan } 3049fa6c0231SZi Yan 3050fa6c0231SZi Yan /* FOLL_DUMP to ignore special (like zero) pages */ 305187d2762eSMiaohe Lin page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); 3052fa6c0231SZi Yan 3053f7091ed6SHaiyue Wang if (IS_ERR_OR_NULL(page)) 3054fa6c0231SZi Yan continue; 3055fa6c0231SZi Yan 3056a644b0abSMatthew Wilcox (Oracle) folio = page_folio(page); 3057a644b0abSMatthew Wilcox (Oracle) if (!is_transparent_hugepage(folio)) 3058fa6c0231SZi Yan goto next; 3059fa6c0231SZi Yan 3060fa6c0231SZi Yan total++; 3061a644b0abSMatthew Wilcox (Oracle) if (!can_split_folio(folio, NULL)) 3062fa6c0231SZi Yan goto next; 3063fa6c0231SZi Yan 3064a644b0abSMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 3065fa6c0231SZi Yan goto next; 3066fa6c0231SZi Yan 3067a644b0abSMatthew Wilcox (Oracle) if (!split_folio(folio)) 3068fa6c0231SZi Yan split++; 3069fa6c0231SZi Yan 3070a644b0abSMatthew Wilcox (Oracle) folio_unlock(folio); 3071fa6c0231SZi Yan next: 3072a644b0abSMatthew Wilcox (Oracle) folio_put(folio); 3073fa6c0231SZi Yan cond_resched(); 3074fa6c0231SZi Yan } 3075fa6c0231SZi Yan mmap_read_unlock(mm); 3076fa6c0231SZi Yan mmput(mm); 3077fa6c0231SZi Yan 3078fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 3079fa6c0231SZi Yan 3080fa6c0231SZi Yan out: 3081fa6c0231SZi Yan return ret; 3082fa6c0231SZi Yan } 3083fa6c0231SZi Yan 3084fbe37501SZi Yan static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, 3085fbe37501SZi Yan pgoff_t off_end) 3086fbe37501SZi Yan { 3087fbe37501SZi Yan struct filename *file; 3088fbe37501SZi Yan struct file *candidate; 3089fbe37501SZi Yan struct address_space *mapping; 3090fbe37501SZi Yan int ret = -EINVAL; 3091fbe37501SZi Yan pgoff_t index; 3092fbe37501SZi Yan int nr_pages = 1; 3093fbe37501SZi Yan unsigned long total = 0, split = 0; 3094fbe37501SZi Yan 3095fbe37501SZi Yan file = getname_kernel(file_path); 3096fbe37501SZi Yan if (IS_ERR(file)) 3097fbe37501SZi Yan return ret; 3098fbe37501SZi Yan 3099fbe37501SZi Yan candidate = file_open_name(file, O_RDONLY, 0); 3100fbe37501SZi Yan if (IS_ERR(candidate)) 3101fbe37501SZi Yan goto out; 3102fbe37501SZi Yan 3103fbe37501SZi Yan pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", 3104fbe37501SZi Yan file_path, off_start, off_end); 3105fbe37501SZi Yan 3106fbe37501SZi Yan mapping = candidate->f_mapping; 3107fbe37501SZi Yan 3108fbe37501SZi Yan for (index = off_start; index < off_end; index += nr_pages) { 31091fb130b2SChristoph Hellwig struct folio *folio = filemap_get_folio(mapping, index); 3110fbe37501SZi Yan 3111fbe37501SZi Yan nr_pages = 1; 311266dabbb6SChristoph Hellwig if (IS_ERR(folio)) 3113fbe37501SZi Yan continue; 3114fbe37501SZi Yan 31159ee2c086SMatthew Wilcox (Oracle) if (!folio_test_large(folio)) 3116fbe37501SZi Yan goto next; 3117fbe37501SZi Yan 3118fbe37501SZi Yan total++; 31199ee2c086SMatthew Wilcox (Oracle) nr_pages = folio_nr_pages(folio); 3120fbe37501SZi Yan 31219ee2c086SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 3122fbe37501SZi Yan goto next; 3123fbe37501SZi Yan 31249ee2c086SMatthew Wilcox (Oracle) if (!split_folio(folio)) 3125fbe37501SZi Yan split++; 3126fbe37501SZi Yan 31279ee2c086SMatthew Wilcox (Oracle) folio_unlock(folio); 3128fbe37501SZi Yan next: 31299ee2c086SMatthew Wilcox (Oracle) folio_put(folio); 3130fbe37501SZi Yan cond_resched(); 3131fbe37501SZi Yan } 3132fbe37501SZi Yan 3133fbe37501SZi Yan filp_close(candidate, NULL); 3134fbe37501SZi Yan ret = 0; 3135fbe37501SZi Yan 3136fbe37501SZi Yan pr_debug("%lu of %lu file-backed THP split\n", split, total); 3137fbe37501SZi Yan out: 3138fbe37501SZi Yan putname(file); 3139fbe37501SZi Yan return ret; 3140fbe37501SZi Yan } 3141fbe37501SZi Yan 3142fa6c0231SZi Yan #define MAX_INPUT_BUF_SZ 255 3143fa6c0231SZi Yan 3144fa6c0231SZi Yan static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, 3145fa6c0231SZi Yan size_t count, loff_t *ppops) 3146fa6c0231SZi Yan { 3147fa6c0231SZi Yan static DEFINE_MUTEX(split_debug_mutex); 3148fa6c0231SZi Yan ssize_t ret; 3149fbe37501SZi Yan /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ 3150fbe37501SZi Yan char input_buf[MAX_INPUT_BUF_SZ]; 3151fa6c0231SZi Yan int pid; 3152fa6c0231SZi Yan unsigned long vaddr_start, vaddr_end; 3153fa6c0231SZi Yan 3154fa6c0231SZi Yan ret = mutex_lock_interruptible(&split_debug_mutex); 3155fa6c0231SZi Yan if (ret) 3156fa6c0231SZi Yan return ret; 3157fa6c0231SZi Yan 3158fa6c0231SZi Yan ret = -EFAULT; 3159fa6c0231SZi Yan 3160fa6c0231SZi Yan memset(input_buf, 0, MAX_INPUT_BUF_SZ); 3161fa6c0231SZi Yan if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) 3162fa6c0231SZi Yan goto out; 3163fa6c0231SZi Yan 3164fa6c0231SZi Yan input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; 3165fbe37501SZi Yan 3166fbe37501SZi Yan if (input_buf[0] == '/') { 3167fbe37501SZi Yan char *tok; 3168fbe37501SZi Yan char *buf = input_buf; 3169fbe37501SZi Yan char file_path[MAX_INPUT_BUF_SZ]; 3170fbe37501SZi Yan pgoff_t off_start = 0, off_end = 0; 3171fbe37501SZi Yan size_t input_len = strlen(input_buf); 3172fbe37501SZi Yan 3173fbe37501SZi Yan tok = strsep(&buf, ","); 3174fbe37501SZi Yan if (tok) { 31751212e00cSMatthew Wilcox (Oracle) strcpy(file_path, tok); 3176fbe37501SZi Yan } else { 3177fbe37501SZi Yan ret = -EINVAL; 3178fbe37501SZi Yan goto out; 3179fbe37501SZi Yan } 3180fbe37501SZi Yan 3181fbe37501SZi Yan ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); 3182fbe37501SZi Yan if (ret != 2) { 3183fbe37501SZi Yan ret = -EINVAL; 3184fbe37501SZi Yan goto out; 3185fbe37501SZi Yan } 3186fbe37501SZi Yan ret = split_huge_pages_in_file(file_path, off_start, off_end); 3187fbe37501SZi Yan if (!ret) 3188fbe37501SZi Yan ret = input_len; 3189fbe37501SZi Yan 3190fbe37501SZi Yan goto out; 3191fbe37501SZi Yan } 3192fbe37501SZi Yan 3193fa6c0231SZi Yan ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); 3194fa6c0231SZi Yan if (ret == 1 && pid == 1) { 3195fa6c0231SZi Yan split_huge_pages_all(); 3196fa6c0231SZi Yan ret = strlen(input_buf); 3197fa6c0231SZi Yan goto out; 3198fa6c0231SZi Yan } else if (ret != 3) { 3199fa6c0231SZi Yan ret = -EINVAL; 3200fa6c0231SZi Yan goto out; 3201fa6c0231SZi Yan } 3202fa6c0231SZi Yan 3203fa6c0231SZi Yan ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); 3204fa6c0231SZi Yan if (!ret) 3205fa6c0231SZi Yan ret = strlen(input_buf); 3206fa6c0231SZi Yan out: 3207fa6c0231SZi Yan mutex_unlock(&split_debug_mutex); 3208fa6c0231SZi Yan return ret; 3209fa6c0231SZi Yan 3210fa6c0231SZi Yan } 3211fa6c0231SZi Yan 3212fa6c0231SZi Yan static const struct file_operations split_huge_pages_fops = { 3213fa6c0231SZi Yan .owner = THIS_MODULE, 3214fa6c0231SZi Yan .write = split_huge_pages_write, 3215fa6c0231SZi Yan .llseek = no_llseek, 3216fa6c0231SZi Yan }; 321749071d43SKirill A. Shutemov 321849071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 321949071d43SKirill A. Shutemov { 3220d9f7979cSGreg Kroah-Hartman debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 322149071d43SKirill A. Shutemov &split_huge_pages_fops); 322249071d43SKirill A. Shutemov return 0; 322349071d43SKirill A. Shutemov } 322449071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 322549071d43SKirill A. Shutemov #endif 3226616b8371SZi Yan 3227616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 32287f5abe60SDavid Hildenbrand int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 3229616b8371SZi Yan struct page *page) 3230616b8371SZi Yan { 3231616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3232616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3233616b8371SZi Yan unsigned long address = pvmw->address; 32346c287605SDavid Hildenbrand bool anon_exclusive; 3235616b8371SZi Yan pmd_t pmdval; 3236616b8371SZi Yan swp_entry_t entry; 3237ab6e3d09SNaoya Horiguchi pmd_t pmdswp; 3238616b8371SZi Yan 3239616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 32407f5abe60SDavid Hildenbrand return 0; 3241616b8371SZi Yan 3242616b8371SZi Yan flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); 32438a8683adSHuang Ying pmdval = pmdp_invalidate(vma, address, pvmw->pmd); 32446c287605SDavid Hildenbrand 3245088b8aa5SDavid Hildenbrand /* See page_try_share_anon_rmap(): invalidate PMD first. */ 32466c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 32476c287605SDavid Hildenbrand if (anon_exclusive && page_try_share_anon_rmap(page)) { 32486c287605SDavid Hildenbrand set_pmd_at(mm, address, pvmw->pmd, pmdval); 32497f5abe60SDavid Hildenbrand return -EBUSY; 32506c287605SDavid Hildenbrand } 32516c287605SDavid Hildenbrand 3252616b8371SZi Yan if (pmd_dirty(pmdval)) 3253616b8371SZi Yan set_page_dirty(page); 32544dd845b5SAlistair Popple if (pmd_write(pmdval)) 32554dd845b5SAlistair Popple entry = make_writable_migration_entry(page_to_pfn(page)); 32566c287605SDavid Hildenbrand else if (anon_exclusive) 32576c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); 32584dd845b5SAlistair Popple else 32594dd845b5SAlistair Popple entry = make_readable_migration_entry(page_to_pfn(page)); 32602e346877SPeter Xu if (pmd_young(pmdval)) 32612e346877SPeter Xu entry = make_migration_entry_young(entry); 32622e346877SPeter Xu if (pmd_dirty(pmdval)) 32632e346877SPeter Xu entry = make_migration_entry_dirty(entry); 3264ab6e3d09SNaoya Horiguchi pmdswp = swp_entry_to_pmd(entry); 3265ab6e3d09SNaoya Horiguchi if (pmd_soft_dirty(pmdval)) 3266ab6e3d09SNaoya Horiguchi pmdswp = pmd_swp_mksoft_dirty(pmdswp); 326724bf08c4SDavid Hildenbrand if (pmd_uffd_wp(pmdval)) 326824bf08c4SDavid Hildenbrand pmdswp = pmd_swp_mkuffd_wp(pmdswp); 3269ab6e3d09SNaoya Horiguchi set_pmd_at(mm, address, pvmw->pmd, pmdswp); 3270cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 3271616b8371SZi Yan put_page(page); 3272283fd6feSAnshuman Khandual trace_set_migration_pmd(address, pmd_val(pmdswp)); 32737f5abe60SDavid Hildenbrand 32747f5abe60SDavid Hildenbrand return 0; 3275616b8371SZi Yan } 3276616b8371SZi Yan 3277616b8371SZi Yan void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 3278616b8371SZi Yan { 3279616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3280616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3281616b8371SZi Yan unsigned long address = pvmw->address; 32824fba8f2aSMiaohe Lin unsigned long haddr = address & HPAGE_PMD_MASK; 3283616b8371SZi Yan pmd_t pmde; 3284616b8371SZi Yan swp_entry_t entry; 3285616b8371SZi Yan 3286616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 3287616b8371SZi Yan return; 3288616b8371SZi Yan 3289616b8371SZi Yan entry = pmd_to_swp_entry(*pvmw->pmd); 3290616b8371SZi Yan get_page(new); 32912e346877SPeter Xu pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); 3292ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pvmw->pmd)) 3293ab6e3d09SNaoya Horiguchi pmde = pmd_mksoft_dirty(pmde); 32943c811f78SDavid Hildenbrand if (is_writable_migration_entry(entry)) 3295161e393cSRick Edgecombe pmde = pmd_mkwrite(pmde, vma); 32968f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*pvmw->pmd)) 3297f1eb1bacSPeter Xu pmde = pmd_mkuffd_wp(pmde); 32982e346877SPeter Xu if (!is_migration_entry_young(entry)) 32992e346877SPeter Xu pmde = pmd_mkold(pmde); 33002e346877SPeter Xu /* NOTE: this may contain setting soft-dirty on some archs */ 33012e346877SPeter Xu if (PageDirty(new) && is_migration_entry_dirty(entry)) 33022e346877SPeter Xu pmde = pmd_mkdirty(pmde); 3303616b8371SZi Yan 33046c287605SDavid Hildenbrand if (PageAnon(new)) { 33056c287605SDavid Hildenbrand rmap_t rmap_flags = RMAP_COMPOUND; 33066c287605SDavid Hildenbrand 33076c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) 33086c287605SDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 33096c287605SDavid Hildenbrand 33104fba8f2aSMiaohe Lin page_add_anon_rmap(new, vma, haddr, rmap_flags); 33116c287605SDavid Hildenbrand } else { 3312cea86fe2SHugh Dickins page_add_file_rmap(new, vma, true); 33136c287605SDavid Hildenbrand } 33146c287605SDavid Hildenbrand VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); 33154fba8f2aSMiaohe Lin set_pmd_at(mm, haddr, pvmw->pmd, pmde); 33165cbcf225SMuchun Song 33175cbcf225SMuchun Song /* No need to invalidate - it was non-present before */ 3318616b8371SZi Yan update_mmu_cache_pmd(vma, address, pvmw->pmd); 3319283fd6feSAnshuman Khandual trace_remove_migration_pmd(address, pmd_val(pmde)); 3320616b8371SZi Yan } 3321616b8371SZi Yan #endif 3322