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 /* 1037da4e2cbSYang Shi * 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 */ 1079fec5168SYang Shi if (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 1359fec5168SYang Shi /* Only regular file is valid */ 1367da4e2cbSYang Shi if (!in_pf && file_thp_enabled(vma)) 13778d12c19SYang Shi return true; 1387635d9cbSMichal Hocko 1399fec5168SYang Shi if (!vma_is_anonymous(vma)) 1407635d9cbSMichal Hocko return false; 1419fec5168SYang Shi 1429fec5168SYang Shi if (vma_is_temporary_stack(vma)) 1439fec5168SYang Shi return false; 1449fec5168SYang Shi 1459fec5168SYang Shi /* 1469fec5168SYang Shi * THPeligible bit of smaps should show 1 for proper VMAs even 1479fec5168SYang Shi * though anon_vma is not initialized yet. 1487da4e2cbSYang Shi * 1497da4e2cbSYang Shi * Allow page fault since anon_vma may be not initialized until 1507da4e2cbSYang Shi * the first page fault. 1519fec5168SYang Shi */ 1529fec5168SYang Shi if (!vma->anon_vma) 1537da4e2cbSYang Shi return (smaps || in_pf); 1549fec5168SYang Shi 1559fec5168SYang Shi return true; 1567635d9cbSMichal Hocko } 1577635d9cbSMichal Hocko 158aaa9705bSMiaohe Lin static bool get_huge_zero_page(void) 15997ae1749SKirill A. Shutemov { 16097ae1749SKirill A. Shutemov struct page *zero_page; 16197ae1749SKirill A. Shutemov retry: 16297ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 163aaa9705bSMiaohe Lin return true; 16497ae1749SKirill A. Shutemov 16597ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 16697ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 167d8a8e1f0SKirill A. Shutemov if (!zero_page) { 168d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 169aaa9705bSMiaohe Lin return false; 170d8a8e1f0SKirill A. Shutemov } 17197ae1749SKirill A. Shutemov preempt_disable(); 1725918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 17397ae1749SKirill A. Shutemov preempt_enable(); 1745ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 17597ae1749SKirill A. Shutemov goto retry; 17697ae1749SKirill A. Shutemov } 1773b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); 17897ae1749SKirill A. Shutemov 17997ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 18097ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 18197ae1749SKirill A. Shutemov preempt_enable(); 182f4981502SLiu Shixin count_vm_event(THP_ZERO_PAGE_ALLOC); 183aaa9705bSMiaohe Lin return true; 18497ae1749SKirill A. Shutemov } 18597ae1749SKirill A. Shutemov 1866fcb52a5SAaron Lu static void put_huge_zero_page(void) 18797ae1749SKirill A. Shutemov { 18897ae1749SKirill A. Shutemov /* 18997ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 19097ae1749SKirill A. Shutemov * last reference. 19197ae1749SKirill A. Shutemov */ 19297ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 19397ae1749SKirill A. Shutemov } 19497ae1749SKirill A. Shutemov 1956fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 1966fcb52a5SAaron Lu { 1976fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1986fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1996fcb52a5SAaron Lu 2006fcb52a5SAaron Lu if (!get_huge_zero_page()) 2016fcb52a5SAaron Lu return NULL; 2026fcb52a5SAaron Lu 2036fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2046fcb52a5SAaron Lu put_huge_zero_page(); 2056fcb52a5SAaron Lu 2066fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 2076fcb52a5SAaron Lu } 2086fcb52a5SAaron Lu 2096fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 2106fcb52a5SAaron Lu { 2116fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2126fcb52a5SAaron Lu put_huge_zero_page(); 2136fcb52a5SAaron Lu } 2146fcb52a5SAaron Lu 21548896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 21697ae1749SKirill A. Shutemov struct shrink_control *sc) 21797ae1749SKirill A. Shutemov { 21897ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 21997ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 22048896466SGlauber Costa } 22197ae1749SKirill A. Shutemov 22248896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 22348896466SGlauber Costa struct shrink_control *sc) 22448896466SGlauber Costa { 22597ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2265918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2275918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2283b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, ~0UL); 2295ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 23048896466SGlauber Costa return HPAGE_PMD_NR; 23197ae1749SKirill A. Shutemov } 23297ae1749SKirill A. Shutemov 23397ae1749SKirill A. Shutemov return 0; 23497ae1749SKirill A. Shutemov } 23597ae1749SKirill A. Shutemov 23654d91729SQi Zheng static struct shrinker *huge_zero_page_shrinker; 23797ae1749SKirill A. Shutemov 23871e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 23971e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 24071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 24171e3aac0SAndrea Arcangeli { 242bfb0ffebSJoe Perches const char *output; 243bfb0ffebSJoe Perches 244444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 245bfb0ffebSJoe Perches output = "[always] madvise never"; 246bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 247bfb0ffebSJoe Perches &transparent_hugepage_flags)) 248bfb0ffebSJoe Perches output = "always [madvise] never"; 249444eb2a4SMel Gorman else 250bfb0ffebSJoe Perches output = "always madvise [never]"; 251bfb0ffebSJoe Perches 252bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 25371e3aac0SAndrea Arcangeli } 254444eb2a4SMel Gorman 25571e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 25671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 25771e3aac0SAndrea Arcangeli const char *buf, size_t count) 25871e3aac0SAndrea Arcangeli { 25921440d7eSDavid Rientjes ssize_t ret = count; 260ba76149fSAndrea Arcangeli 261f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 26221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 26321440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 264f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 26521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 26621440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 267f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 26821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 26921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 27021440d7eSDavid Rientjes } else 27121440d7eSDavid Rientjes ret = -EINVAL; 272ba76149fSAndrea Arcangeli 273ba76149fSAndrea Arcangeli if (ret > 0) { 274b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 275ba76149fSAndrea Arcangeli if (err) 276ba76149fSAndrea Arcangeli ret = err; 277ba76149fSAndrea Arcangeli } 278ba76149fSAndrea Arcangeli return ret; 27971e3aac0SAndrea Arcangeli } 28037139bb0SMiaohe Lin 28137139bb0SMiaohe Lin static struct kobj_attribute enabled_attr = __ATTR_RW(enabled); 28271e3aac0SAndrea Arcangeli 283b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 28471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 28571e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 28671e3aac0SAndrea Arcangeli { 287bfb0ffebSJoe Perches return sysfs_emit(buf, "%d\n", 288e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 28971e3aac0SAndrea Arcangeli } 290e27e6151SBen Hutchings 291b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 29271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 29371e3aac0SAndrea Arcangeli const char *buf, size_t count, 29471e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 29571e3aac0SAndrea Arcangeli { 296e27e6151SBen Hutchings unsigned long value; 297e27e6151SBen Hutchings int ret; 298e27e6151SBen Hutchings 299e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 300e27e6151SBen Hutchings if (ret < 0) 301e27e6151SBen Hutchings return ret; 302e27e6151SBen Hutchings if (value > 1) 30371e3aac0SAndrea Arcangeli return -EINVAL; 30471e3aac0SAndrea Arcangeli 305e27e6151SBen Hutchings if (value) 306e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 307e27e6151SBen Hutchings else 308e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 309e27e6151SBen Hutchings 31071e3aac0SAndrea Arcangeli return count; 31171e3aac0SAndrea Arcangeli } 31271e3aac0SAndrea Arcangeli 31371e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 31471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 31571e3aac0SAndrea Arcangeli { 316bfb0ffebSJoe Perches const char *output; 317bfb0ffebSJoe Perches 318bfb0ffebSJoe Perches if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, 319bfb0ffebSJoe Perches &transparent_hugepage_flags)) 320bfb0ffebSJoe Perches output = "[always] defer defer+madvise madvise never"; 321bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, 322bfb0ffebSJoe Perches &transparent_hugepage_flags)) 323bfb0ffebSJoe Perches output = "always [defer] defer+madvise madvise never"; 324bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, 325bfb0ffebSJoe Perches &transparent_hugepage_flags)) 326bfb0ffebSJoe Perches output = "always defer [defer+madvise] madvise never"; 327bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, 328bfb0ffebSJoe Perches &transparent_hugepage_flags)) 329bfb0ffebSJoe Perches output = "always defer defer+madvise [madvise] never"; 330bfb0ffebSJoe Perches else 331bfb0ffebSJoe Perches output = "always defer defer+madvise madvise [never]"; 332bfb0ffebSJoe Perches 333bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 33471e3aac0SAndrea Arcangeli } 33521440d7eSDavid Rientjes 33671e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 33771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 33871e3aac0SAndrea Arcangeli const char *buf, size_t count) 33971e3aac0SAndrea Arcangeli { 340f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 34121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 34221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 34321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 34421440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 345f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer+madvise")) { 34621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 34721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 34821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 34921440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 350f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer")) { 3514fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 3524fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 3534fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 3544fad7fb6SDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 355f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 35621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 35721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 35821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 35921440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 360f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 36121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 36221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 36321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 36421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 36521440d7eSDavid Rientjes } else 36621440d7eSDavid Rientjes return -EINVAL; 36721440d7eSDavid Rientjes 36821440d7eSDavid Rientjes return count; 36971e3aac0SAndrea Arcangeli } 37037139bb0SMiaohe Lin static struct kobj_attribute defrag_attr = __ATTR_RW(defrag); 37171e3aac0SAndrea Arcangeli 37279da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 37379da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 37479da5407SKirill A. Shutemov { 375b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 37679da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 37779da5407SKirill A. Shutemov } 37879da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 37979da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 38079da5407SKirill A. Shutemov { 381b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 38279da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 38379da5407SKirill A. Shutemov } 38437139bb0SMiaohe Lin static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page); 38549920d28SHugh Dickins 38649920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 38749920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 38849920d28SHugh Dickins { 389ae7a927dSJoe Perches return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); 39049920d28SHugh Dickins } 39149920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 39249920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 39349920d28SHugh Dickins 39471e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 39571e3aac0SAndrea Arcangeli &enabled_attr.attr, 39671e3aac0SAndrea Arcangeli &defrag_attr.attr, 39779da5407SKirill A. Shutemov &use_zero_page_attr.attr, 39849920d28SHugh Dickins &hpage_pmd_size_attr.attr, 399396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_SHMEM 4005a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 4015a6e75f8SKirill A. Shutemov #endif 40271e3aac0SAndrea Arcangeli NULL, 40371e3aac0SAndrea Arcangeli }; 40471e3aac0SAndrea Arcangeli 4058aa95a21SArvind Yadav static const struct attribute_group hugepage_attr_group = { 40671e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 407ba76149fSAndrea Arcangeli }; 408ba76149fSAndrea Arcangeli 409569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 410569e5590SShaohua Li { 411569e5590SShaohua Li int err; 412569e5590SShaohua Li 413569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 414569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 415ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 416569e5590SShaohua Li return -ENOMEM; 417569e5590SShaohua Li } 418569e5590SShaohua Li 419569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 420569e5590SShaohua Li if (err) { 421ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 422569e5590SShaohua Li goto delete_obj; 423569e5590SShaohua Li } 424569e5590SShaohua Li 425569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 426569e5590SShaohua Li if (err) { 427ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 428569e5590SShaohua Li goto remove_hp_group; 429569e5590SShaohua Li } 430569e5590SShaohua Li 431569e5590SShaohua Li return 0; 432569e5590SShaohua Li 433569e5590SShaohua Li remove_hp_group: 434569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 435569e5590SShaohua Li delete_obj: 436569e5590SShaohua Li kobject_put(*hugepage_kobj); 437569e5590SShaohua Li return err; 438569e5590SShaohua Li } 439569e5590SShaohua Li 440569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 441569e5590SShaohua Li { 442569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 443569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 444569e5590SShaohua Li kobject_put(hugepage_kobj); 445569e5590SShaohua Li } 446569e5590SShaohua Li #else 447569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 448569e5590SShaohua Li { 449569e5590SShaohua Li return 0; 450569e5590SShaohua Li } 451569e5590SShaohua Li 452569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 453569e5590SShaohua Li { 454569e5590SShaohua Li } 45571e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 45671e3aac0SAndrea Arcangeli 45754d91729SQi Zheng static int __init thp_shrinker_init(void) 45854d91729SQi Zheng { 45954d91729SQi Zheng huge_zero_page_shrinker = shrinker_alloc(0, "thp-zero"); 46054d91729SQi Zheng if (!huge_zero_page_shrinker) 46154d91729SQi Zheng return -ENOMEM; 46254d91729SQi Zheng 46354d91729SQi Zheng deferred_split_shrinker = shrinker_alloc(SHRINKER_NUMA_AWARE | 46454d91729SQi Zheng SHRINKER_MEMCG_AWARE | 46554d91729SQi Zheng SHRINKER_NONSLAB, 46654d91729SQi Zheng "thp-deferred_split"); 46754d91729SQi Zheng if (!deferred_split_shrinker) { 46854d91729SQi Zheng shrinker_free(huge_zero_page_shrinker); 46954d91729SQi Zheng return -ENOMEM; 47054d91729SQi Zheng } 47154d91729SQi Zheng 47254d91729SQi Zheng huge_zero_page_shrinker->count_objects = shrink_huge_zero_page_count; 47354d91729SQi Zheng huge_zero_page_shrinker->scan_objects = shrink_huge_zero_page_scan; 47454d91729SQi Zheng shrinker_register(huge_zero_page_shrinker); 47554d91729SQi Zheng 47654d91729SQi Zheng deferred_split_shrinker->count_objects = deferred_split_count; 47754d91729SQi Zheng deferred_split_shrinker->scan_objects = deferred_split_scan; 47854d91729SQi Zheng shrinker_register(deferred_split_shrinker); 47954d91729SQi Zheng 48054d91729SQi Zheng return 0; 48154d91729SQi Zheng } 48254d91729SQi Zheng 48354d91729SQi Zheng static void __init thp_shrinker_exit(void) 48454d91729SQi Zheng { 48554d91729SQi Zheng shrinker_free(huge_zero_page_shrinker); 48654d91729SQi Zheng shrinker_free(deferred_split_shrinker); 48754d91729SQi Zheng } 48854d91729SQi Zheng 48971e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 49071e3aac0SAndrea Arcangeli { 49171e3aac0SAndrea Arcangeli int err; 492569e5590SShaohua Li struct kobject *hugepage_kobj; 49371e3aac0SAndrea Arcangeli 4944b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 4953c556d24SPeter Xu transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED; 496569e5590SShaohua Li return -EINVAL; 4974b7167b9SAndrea Arcangeli } 4984b7167b9SAndrea Arcangeli 499ff20c2e0SKirill A. Shutemov /* 500ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 501ff20c2e0SKirill A. Shutemov */ 50223baf831SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER > MAX_ORDER); 503ff20c2e0SKirill A. Shutemov /* 504ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 505ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 506ff20c2e0SKirill A. Shutemov */ 507ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 508ff20c2e0SKirill A. Shutemov 509569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 510569e5590SShaohua Li if (err) 51165ebb64fSKirill A. Shutemov goto err_sysfs; 512ba76149fSAndrea Arcangeli 513b46e756fSKirill A. Shutemov err = khugepaged_init(); 514ba76149fSAndrea Arcangeli if (err) 51565ebb64fSKirill A. Shutemov goto err_slab; 516ba76149fSAndrea Arcangeli 51754d91729SQi Zheng err = thp_shrinker_init(); 51865ebb64fSKirill A. Shutemov if (err) 51954d91729SQi Zheng goto err_shrinker; 52097ae1749SKirill A. Shutemov 52197562cd2SRik van Riel /* 52297562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 52397562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 52497562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 52597562cd2SRik van Riel */ 526ca79b0c2SArun KS if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { 52797562cd2SRik van Riel transparent_hugepage_flags = 0; 52879553da2SKirill A. Shutemov return 0; 52979553da2SKirill A. Shutemov } 53097562cd2SRik van Riel 53179553da2SKirill A. Shutemov err = start_stop_khugepaged(); 53265ebb64fSKirill A. Shutemov if (err) 53365ebb64fSKirill A. Shutemov goto err_khugepaged; 534ba76149fSAndrea Arcangeli 535569e5590SShaohua Li return 0; 53665ebb64fSKirill A. Shutemov err_khugepaged: 53754d91729SQi Zheng thp_shrinker_exit(); 53854d91729SQi Zheng err_shrinker: 539b46e756fSKirill A. Shutemov khugepaged_destroy(); 54065ebb64fSKirill A. Shutemov err_slab: 541569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 54265ebb64fSKirill A. Shutemov err_sysfs: 543ba76149fSAndrea Arcangeli return err; 54471e3aac0SAndrea Arcangeli } 545a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 54671e3aac0SAndrea Arcangeli 54771e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 54871e3aac0SAndrea Arcangeli { 54971e3aac0SAndrea Arcangeli int ret = 0; 55071e3aac0SAndrea Arcangeli if (!str) 55171e3aac0SAndrea Arcangeli goto out; 55271e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 55371e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 55471e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 55571e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 55671e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 55771e3aac0SAndrea Arcangeli ret = 1; 55871e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 55971e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 56071e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56171e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 56271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56371e3aac0SAndrea Arcangeli ret = 1; 56471e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 56571e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 56671e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56771e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 56871e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 56971e3aac0SAndrea Arcangeli ret = 1; 57071e3aac0SAndrea Arcangeli } 57171e3aac0SAndrea Arcangeli out: 57271e3aac0SAndrea Arcangeli if (!ret) 573ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 57471e3aac0SAndrea Arcangeli return ret; 57571e3aac0SAndrea Arcangeli } 57671e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 57771e3aac0SAndrea Arcangeli 578f55e1014SLinus Torvalds pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 57971e3aac0SAndrea Arcangeli { 580f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 581161e393cSRick Edgecombe pmd = pmd_mkwrite(pmd, vma); 58271e3aac0SAndrea Arcangeli return pmd; 58371e3aac0SAndrea Arcangeli } 58471e3aac0SAndrea Arcangeli 58587eaceb3SYang Shi #ifdef CONFIG_MEMCG 586f8baa6beSMatthew Wilcox (Oracle) static inline 587f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *get_deferred_split_queue(struct folio *folio) 5889a982250SKirill A. Shutemov { 589f8baa6beSMatthew Wilcox (Oracle) struct mem_cgroup *memcg = folio_memcg(folio); 590f8baa6beSMatthew Wilcox (Oracle) struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); 59187eaceb3SYang Shi 59287eaceb3SYang Shi if (memcg) 59387eaceb3SYang Shi return &memcg->deferred_split_queue; 59487eaceb3SYang Shi else 59587eaceb3SYang Shi return &pgdat->deferred_split_queue; 5969a982250SKirill A. Shutemov } 59787eaceb3SYang Shi #else 598f8baa6beSMatthew Wilcox (Oracle) static inline 599f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *get_deferred_split_queue(struct folio *folio) 60087eaceb3SYang Shi { 601f8baa6beSMatthew Wilcox (Oracle) struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); 60287eaceb3SYang Shi 60387eaceb3SYang Shi return &pgdat->deferred_split_queue; 60487eaceb3SYang Shi } 60587eaceb3SYang Shi #endif 6069a982250SKirill A. Shutemov 607da6e7bf3SMatthew Wilcox (Oracle) void folio_prep_large_rmappable(struct folio *folio) 6089a982250SKirill A. Shutemov { 6098991de90SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); 6108991de90SMatthew Wilcox (Oracle) INIT_LIST_HEAD(&folio->_deferred_list); 611de53c05fSMatthew Wilcox (Oracle) folio_set_large_rmappable(folio); 6129a982250SKirill A. Shutemov } 6139a982250SKirill A. Shutemov 614a644b0abSMatthew Wilcox (Oracle) static inline bool is_transparent_hugepage(struct folio *folio) 615005ba37cSSean Christopherson { 616a644b0abSMatthew Wilcox (Oracle) if (!folio_test_large(folio)) 617fa1f68ccSZou Wei return false; 618005ba37cSSean Christopherson 619f04029f3SMatthew Wilcox (Oracle) return is_huge_zero_page(&folio->page) || 620de53c05fSMatthew Wilcox (Oracle) folio_test_large_rmappable(folio); 621005ba37cSSean Christopherson } 622005ba37cSSean Christopherson 62397d3d0f9SKirill A. Shutemov static unsigned long __thp_get_unmapped_area(struct file *filp, 62497d3d0f9SKirill A. Shutemov unsigned long addr, unsigned long len, 62574d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 62674d2fad1SToshi Kani { 62774d2fad1SToshi Kani loff_t off_end = off + len; 62874d2fad1SToshi Kani loff_t off_align = round_up(off, size); 62997d3d0f9SKirill A. Shutemov unsigned long len_pad, ret; 63074d2fad1SToshi Kani 63174d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 63274d2fad1SToshi Kani return 0; 63374d2fad1SToshi Kani 63474d2fad1SToshi Kani len_pad = len + size; 63574d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 63674d2fad1SToshi Kani return 0; 63774d2fad1SToshi Kani 63897d3d0f9SKirill A. Shutemov ret = current->mm->get_unmapped_area(filp, addr, len_pad, 63974d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 64097d3d0f9SKirill A. Shutemov 64197d3d0f9SKirill A. Shutemov /* 64297d3d0f9SKirill A. Shutemov * The failure might be due to length padding. The caller will retry 64397d3d0f9SKirill A. Shutemov * without the padding. 64497d3d0f9SKirill A. Shutemov */ 64597d3d0f9SKirill A. Shutemov if (IS_ERR_VALUE(ret)) 64674d2fad1SToshi Kani return 0; 64774d2fad1SToshi Kani 64897d3d0f9SKirill A. Shutemov /* 64997d3d0f9SKirill A. Shutemov * Do not try to align to THP boundary if allocation at the address 65097d3d0f9SKirill A. Shutemov * hint succeeds. 65197d3d0f9SKirill A. Shutemov */ 65297d3d0f9SKirill A. Shutemov if (ret == addr) 65374d2fad1SToshi Kani return addr; 65497d3d0f9SKirill A. Shutemov 65597d3d0f9SKirill A. Shutemov ret += (off - ret) & (size - 1); 65697d3d0f9SKirill A. Shutemov return ret; 65774d2fad1SToshi Kani } 65874d2fad1SToshi Kani 65974d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 66074d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 66174d2fad1SToshi Kani { 66297d3d0f9SKirill A. Shutemov unsigned long ret; 66374d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 66474d2fad1SToshi Kani 66597d3d0f9SKirill A. Shutemov ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); 66697d3d0f9SKirill A. Shutemov if (ret) 66797d3d0f9SKirill A. Shutemov return ret; 6681854bc6eSWilliam Kucharski 66974d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 67074d2fad1SToshi Kani } 67174d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 67274d2fad1SToshi Kani 6732b740303SSouptick Joarder static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, 6742b740303SSouptick Joarder struct page *page, gfp_t gfp) 67571e3aac0SAndrea Arcangeli { 67682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 677cfe3236dSKefeng Wang struct folio *folio = page_folio(page); 67871e3aac0SAndrea Arcangeli pgtable_t pgtable; 67982b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 6802b740303SSouptick Joarder vm_fault_t ret = 0; 68171e3aac0SAndrea Arcangeli 682cfe3236dSKefeng Wang VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 68300501b53SJohannes Weiner 684cfe3236dSKefeng Wang if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) { 685cfe3236dSKefeng Wang folio_put(folio); 6866b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 68785b9f46eSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK_CHARGE); 6886b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 6896b251fc9SAndrea Arcangeli } 690cfe3236dSKefeng Wang folio_throttle_swaprate(folio, gfp); 69171e3aac0SAndrea Arcangeli 6924cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 69300501b53SJohannes Weiner if (unlikely(!pgtable)) { 6946b31d595SMichal Hocko ret = VM_FAULT_OOM; 6956b31d595SMichal Hocko goto release; 69600501b53SJohannes Weiner } 69700501b53SJohannes Weiner 698c79b57e4SHuang Ying clear_huge_page(page, vmf->address, HPAGE_PMD_NR); 69952f37629SMinchan Kim /* 700cfe3236dSKefeng Wang * The memory barrier inside __folio_mark_uptodate makes sure that 70152f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 70252f37629SMinchan Kim * write. 70352f37629SMinchan Kim */ 704cfe3236dSKefeng Wang __folio_mark_uptodate(folio); 70571e3aac0SAndrea Arcangeli 70682b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 70782b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 7086b31d595SMichal Hocko goto unlock_release; 70971e3aac0SAndrea Arcangeli } else { 71071e3aac0SAndrea Arcangeli pmd_t entry; 7116b251fc9SAndrea Arcangeli 7126b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 7136b31d595SMichal Hocko if (ret) 7146b31d595SMichal Hocko goto unlock_release; 7156b31d595SMichal Hocko 7166b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 7176b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 71882b0f8c3SJan Kara spin_unlock(vmf->ptl); 719cfe3236dSKefeng Wang folio_put(folio); 720bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 7218fd5eda4SMiaohe Lin ret = handle_userfault(vmf, VM_UFFD_MISSING); 7228fd5eda4SMiaohe Lin VM_BUG_ON(ret & VM_FAULT_FALLBACK); 7238fd5eda4SMiaohe Lin return ret; 7246b251fc9SAndrea Arcangeli } 7256b251fc9SAndrea Arcangeli 7263122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 727f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 728cfe3236dSKefeng Wang folio_add_new_anon_rmap(folio, vma, haddr); 729cfe3236dSKefeng Wang folio_add_lru_vma(folio, vma); 73082b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 73182b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 732fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 733bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 734c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 73582b0f8c3SJan Kara spin_unlock(vmf->ptl); 7366b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 7379d82c694SJohannes Weiner count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); 73871e3aac0SAndrea Arcangeli } 73971e3aac0SAndrea Arcangeli 740aa2e878eSDavid Rientjes return 0; 7416b31d595SMichal Hocko unlock_release: 7426b31d595SMichal Hocko spin_unlock(vmf->ptl); 7436b31d595SMichal Hocko release: 7446b31d595SMichal Hocko if (pgtable) 7456b31d595SMichal Hocko pte_free(vma->vm_mm, pgtable); 746cfe3236dSKefeng Wang folio_put(folio); 7476b31d595SMichal Hocko return ret; 7486b31d595SMichal Hocko 74971e3aac0SAndrea Arcangeli } 75071e3aac0SAndrea Arcangeli 751444eb2a4SMel Gorman /* 75221440d7eSDavid Rientjes * always: directly stall for all thp allocations 75321440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 75421440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 75521440d7eSDavid Rientjes * fail if not immediately available 75621440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 75721440d7eSDavid Rientjes * available 75821440d7eSDavid Rientjes * never: never stall for any thp allocation 759444eb2a4SMel Gorman */ 760164cc4feSRik van Riel gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) 7610bbbc0b3SAndrea Arcangeli { 762164cc4feSRik van Riel const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); 76389c83fb5SMichal Hocko 764ac79f78dSDavid Rientjes /* Always do synchronous compaction */ 76521440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 766a8282608SAndrea Arcangeli return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 767ac79f78dSDavid Rientjes 768ac79f78dSDavid Rientjes /* Kick kcompactd and fail quickly */ 76921440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 77019deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 771ac79f78dSDavid Rientjes 772ac79f78dSDavid Rientjes /* Synchronous compaction if madvised, otherwise kick kcompactd */ 77321440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 77419deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 77519deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 776ac79f78dSDavid Rientjes __GFP_KSWAPD_RECLAIM); 777ac79f78dSDavid Rientjes 778ac79f78dSDavid Rientjes /* Only do synchronous compaction if madvised */ 77921440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 78019deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 78119deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); 782ac79f78dSDavid Rientjes 78319deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT; 784444eb2a4SMel Gorman } 785444eb2a4SMel Gorman 786c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 7872efeb8daSMiaohe Lin static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 78897ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 7895918d10aSKirill A. Shutemov struct page *zero_page) 790fc9fe822SKirill A. Shutemov { 791fc9fe822SKirill A. Shutemov pmd_t entry; 7927c414164SAndrew Morton if (!pmd_none(*pmd)) 7932efeb8daSMiaohe Lin return; 7945918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 795fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 7966b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 797fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 798c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 799fc9fe822SKirill A. Shutemov } 800fc9fe822SKirill A. Shutemov 8012b740303SSouptick Joarder vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) 80271e3aac0SAndrea Arcangeli { 80382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 804077fcf11SAneesh Kumar K.V gfp_t gfp; 805cb196ee1SMatthew Wilcox (Oracle) struct folio *folio; 80682b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 80771e3aac0SAndrea Arcangeli 80843675e6fSYang Shi if (!transhuge_vma_suitable(vma, haddr)) 809c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 81071e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 81171e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 8124fa6893fSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 813d2081b2bSYang Shi 81482b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 815bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 81679da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 81780371957SKirill A. Shutemov pgtable_t pgtable; 8185918d10aSKirill A. Shutemov struct page *zero_page; 8192b740303SSouptick Joarder vm_fault_t ret; 8204cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 82180371957SKirill A. Shutemov if (unlikely(!pgtable)) 82280371957SKirill A. Shutemov return VM_FAULT_OOM; 8236fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 8245918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 825bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 82697ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 827c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 82897ae1749SKirill A. Shutemov } 82982b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 8306b251fc9SAndrea Arcangeli ret = 0; 83182b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 8326b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 8336b31d595SMichal Hocko if (ret) { 8346b31d595SMichal Hocko spin_unlock(vmf->ptl); 835bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 8366b31d595SMichal Hocko } else if (userfaultfd_missing(vma)) { 83782b0f8c3SJan Kara spin_unlock(vmf->ptl); 838bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 83982b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 8406b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 8416b251fc9SAndrea Arcangeli } else { 842bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 84382b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 844fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 84582b0f8c3SJan Kara spin_unlock(vmf->ptl); 8466b251fc9SAndrea Arcangeli } 847bfe8cc1dSGerald Schaefer } else { 84882b0f8c3SJan Kara spin_unlock(vmf->ptl); 849bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 850bfe8cc1dSGerald Schaefer } 8516b251fc9SAndrea Arcangeli return ret; 85280371957SKirill A. Shutemov } 853164cc4feSRik van Riel gfp = vma_thp_gfp_mask(vma); 854cb196ee1SMatthew Wilcox (Oracle) folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); 855cb196ee1SMatthew Wilcox (Oracle) if (unlikely(!folio)) { 85681ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 857c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 85881ab4201SAndi Kleen } 859cb196ee1SMatthew Wilcox (Oracle) return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); 86071e3aac0SAndrea Arcangeli } 86171e3aac0SAndrea Arcangeli 862ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 8633b6521f5SOliver O'Halloran pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, 8643b6521f5SOliver O'Halloran pgtable_t pgtable) 8655cad465dSMatthew Wilcox { 8665cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 8675cad465dSMatthew Wilcox pmd_t entry; 8685cad465dSMatthew Wilcox spinlock_t *ptl; 8695cad465dSMatthew Wilcox 8705cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 871c6f3c5eeSAneesh Kumar K.V if (!pmd_none(*pmd)) { 872c6f3c5eeSAneesh Kumar K.V if (write) { 873c6f3c5eeSAneesh Kumar K.V if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { 874c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); 875c6f3c5eeSAneesh Kumar K.V goto out_unlock; 876c6f3c5eeSAneesh Kumar K.V } 877c6f3c5eeSAneesh Kumar K.V entry = pmd_mkyoung(*pmd); 878c6f3c5eeSAneesh Kumar K.V entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 879c6f3c5eeSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) 880c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 881c6f3c5eeSAneesh Kumar K.V } 882c6f3c5eeSAneesh Kumar K.V 883c6f3c5eeSAneesh Kumar K.V goto out_unlock; 884c6f3c5eeSAneesh Kumar K.V } 885c6f3c5eeSAneesh Kumar K.V 886f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 887f25748e3SDan Williams if (pfn_t_devmap(pfn)) 888f25748e3SDan Williams entry = pmd_mkdevmap(entry); 8895cad465dSMatthew Wilcox if (write) { 890f55e1014SLinus Torvalds entry = pmd_mkyoung(pmd_mkdirty(entry)); 891f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(entry, vma); 8925cad465dSMatthew Wilcox } 8933b6521f5SOliver O'Halloran 8943b6521f5SOliver O'Halloran if (pgtable) { 8953b6521f5SOliver O'Halloran pgtable_trans_huge_deposit(mm, pmd, pgtable); 896c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 897c6f3c5eeSAneesh Kumar K.V pgtable = NULL; 8983b6521f5SOliver O'Halloran } 8993b6521f5SOliver O'Halloran 9005cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 9015cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 902c6f3c5eeSAneesh Kumar K.V 903c6f3c5eeSAneesh Kumar K.V out_unlock: 9045cad465dSMatthew Wilcox spin_unlock(ptl); 905c6f3c5eeSAneesh Kumar K.V if (pgtable) 906c6f3c5eeSAneesh Kumar K.V pte_free(mm, pgtable); 9075cad465dSMatthew Wilcox } 9085cad465dSMatthew Wilcox 9099a9731b1SThomas Hellstrom (VMware) /** 9107b806d22SLorenzo Stoakes * vmf_insert_pfn_pmd - insert a pmd size pfn 9119a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 9129a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 9139a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 9149a9731b1SThomas Hellstrom (VMware) * 9157b806d22SLorenzo Stoakes * Insert a pmd size pfn. See vmf_insert_pfn() for additional info. 9169a9731b1SThomas Hellstrom (VMware) * 9179a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 9189a9731b1SThomas Hellstrom (VMware) */ 9197b806d22SLorenzo Stoakes vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) 9205cad465dSMatthew Wilcox { 921fce86ff5SDan Williams unsigned long addr = vmf->address & PMD_MASK; 922fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 9237b806d22SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 9243b6521f5SOliver O'Halloran pgtable_t pgtable = NULL; 925fce86ff5SDan Williams 9265cad465dSMatthew Wilcox /* 9275cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 9285cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 9295cad465dSMatthew Wilcox * can't support a 'special' bit. 9305cad465dSMatthew Wilcox */ 931e1fb4a08SDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 932e1fb4a08SDave Jiang !pfn_t_devmap(pfn)); 9335cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 9345cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 9355cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 9365cad465dSMatthew Wilcox 9375cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 9385cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 939308a047cSBorislav Petkov 9403b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) { 9414cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 9423b6521f5SOliver O'Halloran if (!pgtable) 9433b6521f5SOliver O'Halloran return VM_FAULT_OOM; 9443b6521f5SOliver O'Halloran } 9453b6521f5SOliver O'Halloran 946308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 947308a047cSBorislav Petkov 948fce86ff5SDan Williams insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); 949ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 9505cad465dSMatthew Wilcox } 9517b806d22SLorenzo Stoakes EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); 9525cad465dSMatthew Wilcox 953a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 954f55e1014SLinus Torvalds static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 955a00cc7d9SMatthew Wilcox { 956f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 957a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 958a00cc7d9SMatthew Wilcox return pud; 959a00cc7d9SMatthew Wilcox } 960a00cc7d9SMatthew Wilcox 961a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 9627b806d22SLorenzo Stoakes pud_t *pud, pfn_t pfn, bool write) 963a00cc7d9SMatthew Wilcox { 964a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 9657b806d22SLorenzo Stoakes pgprot_t prot = vma->vm_page_prot; 966a00cc7d9SMatthew Wilcox pud_t entry; 967a00cc7d9SMatthew Wilcox spinlock_t *ptl; 968a00cc7d9SMatthew Wilcox 969a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 970c6f3c5eeSAneesh Kumar K.V if (!pud_none(*pud)) { 971c6f3c5eeSAneesh Kumar K.V if (write) { 972c6f3c5eeSAneesh Kumar K.V if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { 973c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pud(*pud)); 974c6f3c5eeSAneesh Kumar K.V goto out_unlock; 975c6f3c5eeSAneesh Kumar K.V } 976c6f3c5eeSAneesh Kumar K.V entry = pud_mkyoung(*pud); 977c6f3c5eeSAneesh Kumar K.V entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); 978c6f3c5eeSAneesh Kumar K.V if (pudp_set_access_flags(vma, addr, pud, entry, 1)) 979c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pud(vma, addr, pud); 980c6f3c5eeSAneesh Kumar K.V } 981c6f3c5eeSAneesh Kumar K.V goto out_unlock; 982c6f3c5eeSAneesh Kumar K.V } 983c6f3c5eeSAneesh Kumar K.V 984a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 985a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 986a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 987a00cc7d9SMatthew Wilcox if (write) { 988f55e1014SLinus Torvalds entry = pud_mkyoung(pud_mkdirty(entry)); 989f55e1014SLinus Torvalds entry = maybe_pud_mkwrite(entry, vma); 990a00cc7d9SMatthew Wilcox } 991a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 992a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 993c6f3c5eeSAneesh Kumar K.V 994c6f3c5eeSAneesh Kumar K.V out_unlock: 995a00cc7d9SMatthew Wilcox spin_unlock(ptl); 996a00cc7d9SMatthew Wilcox } 997a00cc7d9SMatthew Wilcox 9989a9731b1SThomas Hellstrom (VMware) /** 9997b806d22SLorenzo Stoakes * vmf_insert_pfn_pud - insert a pud size pfn 10009a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 10019a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 10029a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 10039a9731b1SThomas Hellstrom (VMware) * 10047b806d22SLorenzo Stoakes * Insert a pud size pfn. See vmf_insert_pfn() for additional info. 10059a9731b1SThomas Hellstrom (VMware) * 10069a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 10079a9731b1SThomas Hellstrom (VMware) */ 10087b806d22SLorenzo Stoakes vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) 1009a00cc7d9SMatthew Wilcox { 1010fce86ff5SDan Williams unsigned long addr = vmf->address & PUD_MASK; 1011fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 10127b806d22SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 1013fce86ff5SDan Williams 1014a00cc7d9SMatthew Wilcox /* 1015a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 1016a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 1017a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 1018a00cc7d9SMatthew Wilcox */ 101962ec0d8cSDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 102062ec0d8cSDave Jiang !pfn_t_devmap(pfn)); 1021a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 1022a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 1023a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 1024a00cc7d9SMatthew Wilcox 1025a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 1026a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 1027a00cc7d9SMatthew Wilcox 1028a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 1029a00cc7d9SMatthew Wilcox 10307b806d22SLorenzo Stoakes insert_pfn_pud(vma, addr, vmf->pud, pfn, write); 1031a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 1032a00cc7d9SMatthew Wilcox } 10337b806d22SLorenzo Stoakes EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); 1034a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1035a00cc7d9SMatthew Wilcox 10363565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 1037a69e4717SMiaohe Lin pmd_t *pmd, bool write) 10383565fce3SDan Williams { 10393565fce3SDan Williams pmd_t _pmd; 10403565fce3SDan Williams 1041a8f97366SKirill A. Shutemov _pmd = pmd_mkyoung(*pmd); 1042a69e4717SMiaohe Lin if (write) 1043a8f97366SKirill A. Shutemov _pmd = pmd_mkdirty(_pmd); 10443565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 1045a69e4717SMiaohe Lin pmd, _pmd, write)) 10463565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 10473565fce3SDan Williams } 10483565fce3SDan Williams 10493565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 1050df06b37fSKeith Busch pmd_t *pmd, int flags, struct dev_pagemap **pgmap) 10513565fce3SDan Williams { 10523565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 10533565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 10543565fce3SDan Williams struct page *page; 10550f089235SLogan Gunthorpe int ret; 10563565fce3SDan Williams 10573565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 10583565fce3SDan Williams 1059f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pmd_write(*pmd)) 10603565fce3SDan Williams return NULL; 10613565fce3SDan Williams 10623565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 10633565fce3SDan Williams /* pass */; 10643565fce3SDan Williams else 10653565fce3SDan Williams return NULL; 10663565fce3SDan Williams 10673565fce3SDan Williams if (flags & FOLL_TOUCH) 1068a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 10693565fce3SDan Williams 10703565fce3SDan Williams /* 10713565fce3SDan Williams * device mapped pages can only be returned if the 10723565fce3SDan Williams * caller will manage the page reference count. 10733565fce3SDan Williams */ 10743faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 10753565fce3SDan Williams return ERR_PTR(-EEXIST); 10763565fce3SDan Williams 10773565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 1078df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1079df06b37fSKeith Busch if (!*pgmap) 10803565fce3SDan Williams return ERR_PTR(-EFAULT); 10813565fce3SDan Williams page = pfn_to_page(pfn); 10820f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 10830f089235SLogan Gunthorpe if (ret) 10840f089235SLogan Gunthorpe page = ERR_PTR(ret); 10853565fce3SDan Williams 10863565fce3SDan Williams return page; 10873565fce3SDan Williams } 10883565fce3SDan Williams 108971e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 109071e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 10918f34f1eaSPeter Xu struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 109271e3aac0SAndrea Arcangeli { 1093c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 109471e3aac0SAndrea Arcangeli struct page *src_page; 109571e3aac0SAndrea Arcangeli pmd_t pmd; 109612c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 1097628d47ceSKirill A. Shutemov int ret = -ENOMEM; 109871e3aac0SAndrea Arcangeli 1099628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 11008f34f1eaSPeter Xu if (!vma_is_anonymous(dst_vma)) 1101628d47ceSKirill A. Shutemov return 0; 1102628d47ceSKirill A. Shutemov 11034cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(dst_mm); 110471e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 110571e3aac0SAndrea Arcangeli goto out; 110671e3aac0SAndrea Arcangeli 1107c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 1108c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 1109c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 111071e3aac0SAndrea Arcangeli 111171e3aac0SAndrea Arcangeli ret = -EAGAIN; 111271e3aac0SAndrea Arcangeli pmd = *src_pmd; 111384c3fc4eSZi Yan 111484c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 111584c3fc4eSZi Yan if (unlikely(is_swap_pmd(pmd))) { 111684c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(pmd); 111784c3fc4eSZi Yan 111884c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(pmd)); 11196c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) { 11204dd845b5SAlistair Popple entry = make_readable_migration_entry( 11214dd845b5SAlistair Popple swp_offset(entry)); 112284c3fc4eSZi Yan pmd = swp_entry_to_pmd(entry); 1123ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*src_pmd)) 1124ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 11258f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*src_pmd)) 11268f34f1eaSPeter Xu pmd = pmd_swp_mkuffd_wp(pmd); 112784c3fc4eSZi Yan set_pmd_at(src_mm, addr, src_pmd, pmd); 112884c3fc4eSZi Yan } 1129dd8a67f9SZi Yan add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1130af5b0f6aSKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 1131dd8a67f9SZi Yan pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 11328f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11338f34f1eaSPeter Xu pmd = pmd_swp_clear_uffd_wp(pmd); 113484c3fc4eSZi Yan set_pmd_at(dst_mm, addr, dst_pmd, pmd); 113584c3fc4eSZi Yan ret = 0; 113684c3fc4eSZi Yan goto out_unlock; 113784c3fc4eSZi Yan } 113884c3fc4eSZi Yan #endif 113984c3fc4eSZi Yan 1140628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 114171e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 114271e3aac0SAndrea Arcangeli goto out_unlock; 114371e3aac0SAndrea Arcangeli } 1144fc9fe822SKirill A. Shutemov /* 1145c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 1146fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 1147fc9fe822SKirill A. Shutemov * a page table. 1148fc9fe822SKirill A. Shutemov */ 1149fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 115097ae1749SKirill A. Shutemov /* 115197ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 115297ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 115397ae1749SKirill A. Shutemov * reference. 115497ae1749SKirill A. Shutemov */ 11555fc7a5f6SPeter Xu mm_get_huge_zero_page(dst_mm); 11565fc7a5f6SPeter Xu goto out_zero_page; 1157fc9fe822SKirill A. Shutemov } 1158de466bd6SMel Gorman 115971e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 1160309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 1161d042035eSPeter Xu 1162fb3d824dSDavid Hildenbrand get_page(src_page); 1163fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { 1164fb3d824dSDavid Hildenbrand /* Page maybe pinned: split and retry the fault on PTEs. */ 1165fb3d824dSDavid Hildenbrand put_page(src_page); 1166d042035eSPeter Xu pte_free(dst_mm, pgtable); 1167d042035eSPeter Xu spin_unlock(src_ptl); 1168d042035eSPeter Xu spin_unlock(dst_ptl); 11698f34f1eaSPeter Xu __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); 1170d042035eSPeter Xu return -EAGAIN; 1171d042035eSPeter Xu } 117271e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 11735fc7a5f6SPeter Xu out_zero_page: 1174c4812909SKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 11755c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 117671e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 11778f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11788f34f1eaSPeter Xu pmd = pmd_clear_uffd_wp(pmd); 117971e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 118071e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 118171e3aac0SAndrea Arcangeli 118271e3aac0SAndrea Arcangeli ret = 0; 118371e3aac0SAndrea Arcangeli out_unlock: 1184c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 1185c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 118671e3aac0SAndrea Arcangeli out: 118771e3aac0SAndrea Arcangeli return ret; 118871e3aac0SAndrea Arcangeli } 118971e3aac0SAndrea Arcangeli 1190a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1191a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 11925fe653e9SMiaohe Lin pud_t *pud, bool write) 1193a00cc7d9SMatthew Wilcox { 1194a00cc7d9SMatthew Wilcox pud_t _pud; 1195a00cc7d9SMatthew Wilcox 1196a8f97366SKirill A. Shutemov _pud = pud_mkyoung(*pud); 11975fe653e9SMiaohe Lin if (write) 1198a8f97366SKirill A. Shutemov _pud = pud_mkdirty(_pud); 1199a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 12005fe653e9SMiaohe Lin pud, _pud, write)) 1201a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1202a00cc7d9SMatthew Wilcox } 1203a00cc7d9SMatthew Wilcox 1204a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 1205df06b37fSKeith Busch pud_t *pud, int flags, struct dev_pagemap **pgmap) 1206a00cc7d9SMatthew Wilcox { 1207a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 1208a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1209a00cc7d9SMatthew Wilcox struct page *page; 12100f089235SLogan Gunthorpe int ret; 1211a00cc7d9SMatthew Wilcox 1212a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 1213a00cc7d9SMatthew Wilcox 1214f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pud_write(*pud)) 1215a00cc7d9SMatthew Wilcox return NULL; 1216a00cc7d9SMatthew Wilcox 1217a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 1218a00cc7d9SMatthew Wilcox /* pass */; 1219a00cc7d9SMatthew Wilcox else 1220a00cc7d9SMatthew Wilcox return NULL; 1221a00cc7d9SMatthew Wilcox 1222a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 12235fe653e9SMiaohe Lin touch_pud(vma, addr, pud, flags & FOLL_WRITE); 1224a00cc7d9SMatthew Wilcox 1225a00cc7d9SMatthew Wilcox /* 1226a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 1227a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 12283faa52c0SJohn Hubbard * 12293faa52c0SJohn Hubbard * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: 1230a00cc7d9SMatthew Wilcox */ 12313faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 1232a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 1233a00cc7d9SMatthew Wilcox 1234a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 1235df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1236df06b37fSKeith Busch if (!*pgmap) 1237a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 1238a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 12390f089235SLogan Gunthorpe 12400f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 12410f089235SLogan Gunthorpe if (ret) 12420f089235SLogan Gunthorpe page = ERR_PTR(ret); 1243a00cc7d9SMatthew Wilcox 1244a00cc7d9SMatthew Wilcox return page; 1245a00cc7d9SMatthew Wilcox } 1246a00cc7d9SMatthew Wilcox 1247a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1248a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1249a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1250a00cc7d9SMatthew Wilcox { 1251a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1252a00cc7d9SMatthew Wilcox pud_t pud; 1253a00cc7d9SMatthew Wilcox int ret; 1254a00cc7d9SMatthew Wilcox 1255a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1256a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1257a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1258a00cc7d9SMatthew Wilcox 1259a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1260a00cc7d9SMatthew Wilcox pud = *src_pud; 1261a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1262a00cc7d9SMatthew Wilcox goto out_unlock; 1263a00cc7d9SMatthew Wilcox 1264a00cc7d9SMatthew Wilcox /* 1265a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1266a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1267a00cc7d9SMatthew Wilcox * a page table. 1268a00cc7d9SMatthew Wilcox */ 1269a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1270a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1271a00cc7d9SMatthew Wilcox } 1272a00cc7d9SMatthew Wilcox 1273fb3d824dSDavid Hildenbrand /* 1274fb3d824dSDavid Hildenbrand * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() 1275fb3d824dSDavid Hildenbrand * and split if duplicating fails. 1276fb3d824dSDavid Hildenbrand */ 1277a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1278a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1279a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1280a00cc7d9SMatthew Wilcox 1281a00cc7d9SMatthew Wilcox ret = 0; 1282a00cc7d9SMatthew Wilcox out_unlock: 1283a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1284a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1285a00cc7d9SMatthew Wilcox return ret; 1286a00cc7d9SMatthew Wilcox } 1287a00cc7d9SMatthew Wilcox 1288a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1289a00cc7d9SMatthew Wilcox { 1290a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1291a00cc7d9SMatthew Wilcox 1292a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1293a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1294a00cc7d9SMatthew Wilcox goto unlock; 1295a00cc7d9SMatthew Wilcox 12965fe653e9SMiaohe Lin touch_pud(vmf->vma, vmf->address, vmf->pud, write); 1297a00cc7d9SMatthew Wilcox unlock: 1298a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1299a00cc7d9SMatthew Wilcox } 1300a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1301a00cc7d9SMatthew Wilcox 13025db4f15cSYang Shi void huge_pmd_set_accessed(struct vm_fault *vmf) 1303a1dd450bSWill Deacon { 130420f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1305a1dd450bSWill Deacon 130682b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 1307a69e4717SMiaohe Lin if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) 1308a1dd450bSWill Deacon goto unlock; 1309a1dd450bSWill Deacon 1310a69e4717SMiaohe Lin touch_pmd(vmf->vma, vmf->address, vmf->pmd, write); 1311a1dd450bSWill Deacon 1312a1dd450bSWill Deacon unlock: 131382b0f8c3SJan Kara spin_unlock(vmf->ptl); 1314a1dd450bSWill Deacon } 1315a1dd450bSWill Deacon 13165db4f15cSYang Shi vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) 131771e3aac0SAndrea Arcangeli { 1318c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 131982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 13202fad3d14SMatthew Wilcox (Oracle) struct folio *folio; 13213917c802SKirill A. Shutemov struct page *page; 132282b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 13235db4f15cSYang Shi pmd_t orig_pmd = vmf->orig_pmd; 132471e3aac0SAndrea Arcangeli 132582b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 132681d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 13273917c802SKirill A. Shutemov 132893b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 13293917c802SKirill A. Shutemov goto fallback; 13303917c802SKirill A. Shutemov 133182b0f8c3SJan Kara spin_lock(vmf->ptl); 13323917c802SKirill A. Shutemov 13333917c802SKirill A. Shutemov if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13343917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13353917c802SKirill A. Shutemov return 0; 13363917c802SKirill A. Shutemov } 133771e3aac0SAndrea Arcangeli 133871e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 13392fad3d14SMatthew Wilcox (Oracle) folio = page_folio(page); 1340f6004e73SMiaohe Lin VM_BUG_ON_PAGE(!PageHead(page), page); 13413917c802SKirill A. Shutemov 13426c287605SDavid Hildenbrand /* Early check when only holding the PT lock. */ 13436c287605SDavid Hildenbrand if (PageAnonExclusive(page)) 13446c287605SDavid Hildenbrand goto reuse; 13456c287605SDavid Hildenbrand 13462fad3d14SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) { 13472fad3d14SMatthew Wilcox (Oracle) folio_get(folio); 1348ba3c4ce6SHuang Ying spin_unlock(vmf->ptl); 13492fad3d14SMatthew Wilcox (Oracle) folio_lock(folio); 1350ba3c4ce6SHuang Ying spin_lock(vmf->ptl); 1351ba3c4ce6SHuang Ying if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13523917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13532fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13542fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 13553917c802SKirill A. Shutemov return 0; 1356ba3c4ce6SHuang Ying } 13572fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 1358ba3c4ce6SHuang Ying } 13593917c802SKirill A. Shutemov 13606c287605SDavid Hildenbrand /* Recheck after temporarily dropping the PT lock. */ 13616c287605SDavid Hildenbrand if (PageAnonExclusive(page)) { 13622fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13636c287605SDavid Hildenbrand goto reuse; 13646c287605SDavid Hildenbrand } 13656c287605SDavid Hildenbrand 13663917c802SKirill A. Shutemov /* 13672fad3d14SMatthew Wilcox (Oracle) * See do_wp_page(): we can only reuse the folio exclusively if 13682fad3d14SMatthew Wilcox (Oracle) * there are no additional references. Note that we always drain 13691fec6890SMatthew Wilcox (Oracle) * the LRU cache immediately after adding a THP. 13703917c802SKirill A. Shutemov */ 13712fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) > 13722fad3d14SMatthew Wilcox (Oracle) 1 + folio_test_swapcache(folio) * folio_nr_pages(folio)) 13733bff7e3fSDavid Hildenbrand goto unlock_fallback; 13742fad3d14SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 13752fad3d14SMatthew Wilcox (Oracle) folio_free_swap(folio); 13762fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) == 1) { 137771e3aac0SAndrea Arcangeli pmd_t entry; 13786c54dc6cSDavid Hildenbrand 13796c54dc6cSDavid Hildenbrand page_move_anon_rmap(page, vma); 1380*5ca43289SDavid Hildenbrand SetPageAnonExclusive(page); 13812fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13826c287605SDavid Hildenbrand reuse: 1383c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 1384c89357e2SDavid Hildenbrand spin_unlock(vmf->ptl); 1385c89357e2SDavid Hildenbrand return 0; 1386c89357e2SDavid Hildenbrand } 138771e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 1388f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 138982b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 139082b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 13913917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 1392cb8d8633SDavid Hildenbrand return 0; 139371e3aac0SAndrea Arcangeli } 13943917c802SKirill A. Shutemov 13953bff7e3fSDavid Hildenbrand unlock_fallback: 13962fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 139782b0f8c3SJan Kara spin_unlock(vmf->ptl); 13983917c802SKirill A. Shutemov fallback: 13993917c802SKirill A. Shutemov __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); 14003917c802SKirill A. Shutemov return VM_FAULT_FALLBACK; 140171e3aac0SAndrea Arcangeli } 140271e3aac0SAndrea Arcangeli 1403c27f479eSDavid Hildenbrand static inline bool can_change_pmd_writable(struct vm_area_struct *vma, 1404c27f479eSDavid Hildenbrand unsigned long addr, pmd_t pmd) 1405c27f479eSDavid Hildenbrand { 1406c27f479eSDavid Hildenbrand struct page *page; 1407c27f479eSDavid Hildenbrand 1408c27f479eSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) 1409c27f479eSDavid Hildenbrand return false; 1410c27f479eSDavid Hildenbrand 1411c27f479eSDavid Hildenbrand /* Don't touch entries that are not even readable (NUMA hinting). */ 1412c27f479eSDavid Hildenbrand if (pmd_protnone(pmd)) 1413c27f479eSDavid Hildenbrand return false; 1414c27f479eSDavid Hildenbrand 1415c27f479eSDavid Hildenbrand /* Do we need write faults for softdirty tracking? */ 1416c27f479eSDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 1417c27f479eSDavid Hildenbrand return false; 1418c27f479eSDavid Hildenbrand 1419c27f479eSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 1420c27f479eSDavid Hildenbrand if (userfaultfd_huge_pmd_wp(vma, pmd)) 1421c27f479eSDavid Hildenbrand return false; 1422c27f479eSDavid Hildenbrand 1423c27f479eSDavid Hildenbrand if (!(vma->vm_flags & VM_SHARED)) { 1424c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1425c27f479eSDavid Hildenbrand page = vm_normal_page_pmd(vma, addr, pmd); 1426c27f479eSDavid Hildenbrand return page && PageAnon(page) && PageAnonExclusive(page); 1427c27f479eSDavid Hildenbrand } 1428c27f479eSDavid Hildenbrand 1429c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1430c27f479eSDavid Hildenbrand return pmd_dirty(pmd); 1431c27f479eSDavid Hildenbrand } 1432c27f479eSDavid Hildenbrand 14335535be30SDavid Hildenbrand /* FOLL_FORCE can write to even unwritable PMDs in COW mappings. */ 14345535be30SDavid Hildenbrand static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, 14355535be30SDavid Hildenbrand struct vm_area_struct *vma, 14365535be30SDavid Hildenbrand unsigned int flags) 14378310d48bSKeno Fischer { 14385535be30SDavid Hildenbrand /* If the pmd is writable, we can write to the page. */ 14395535be30SDavid Hildenbrand if (pmd_write(pmd)) 14405535be30SDavid Hildenbrand return true; 14415535be30SDavid Hildenbrand 14425535be30SDavid Hildenbrand /* Maybe FOLL_FORCE is set to override it? */ 14435535be30SDavid Hildenbrand if (!(flags & FOLL_FORCE)) 14445535be30SDavid Hildenbrand return false; 14455535be30SDavid Hildenbrand 14465535be30SDavid Hildenbrand /* But FOLL_FORCE has no effect on shared mappings */ 14475535be30SDavid Hildenbrand if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED)) 14485535be30SDavid Hildenbrand return false; 14495535be30SDavid Hildenbrand 14505535be30SDavid Hildenbrand /* ... or read-only private ones */ 14515535be30SDavid Hildenbrand if (!(vma->vm_flags & VM_MAYWRITE)) 14525535be30SDavid Hildenbrand return false; 14535535be30SDavid Hildenbrand 14545535be30SDavid Hildenbrand /* ... or already writable ones that just need to take a write fault */ 14555535be30SDavid Hildenbrand if (vma->vm_flags & VM_WRITE) 14565535be30SDavid Hildenbrand return false; 14575535be30SDavid Hildenbrand 14585535be30SDavid Hildenbrand /* 14595535be30SDavid Hildenbrand * See can_change_pte_writable(): we broke COW and could map the page 14605535be30SDavid Hildenbrand * writable if we have an exclusive anonymous page ... 14615535be30SDavid Hildenbrand */ 14625535be30SDavid Hildenbrand if (!page || !PageAnon(page) || !PageAnonExclusive(page)) 14635535be30SDavid Hildenbrand return false; 14645535be30SDavid Hildenbrand 14655535be30SDavid Hildenbrand /* ... and a write-fault isn't required for other reasons. */ 14665535be30SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 14675535be30SDavid Hildenbrand return false; 14685535be30SDavid Hildenbrand return !userfaultfd_huge_pmd_wp(vma, pmd); 14698310d48bSKeno Fischer } 14708310d48bSKeno Fischer 1471b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 147271e3aac0SAndrea Arcangeli unsigned long addr, 147371e3aac0SAndrea Arcangeli pmd_t *pmd, 147471e3aac0SAndrea Arcangeli unsigned int flags) 147571e3aac0SAndrea Arcangeli { 1476b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 14775535be30SDavid Hildenbrand struct page *page; 14780f089235SLogan Gunthorpe int ret; 147971e3aac0SAndrea Arcangeli 1480c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 148171e3aac0SAndrea Arcangeli 14825535be30SDavid Hildenbrand page = pmd_page(*pmd); 14835535be30SDavid Hildenbrand VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 14845535be30SDavid Hildenbrand 14855535be30SDavid Hildenbrand if ((flags & FOLL_WRITE) && 14865535be30SDavid Hildenbrand !can_follow_write_pmd(*pmd, page, vma, flags)) 14875535be30SDavid Hildenbrand return NULL; 148871e3aac0SAndrea Arcangeli 148985facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 149085facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 149185facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 149285facf25SKirill A. Shutemov 1493d74943a2SDavid Hildenbrand if (pmd_protnone(*pmd) && !gup_can_follow_protnone(vma, flags)) 14945535be30SDavid Hildenbrand return NULL; 14953faa52c0SJohn Hubbard 149684209e87SDavid Hildenbrand if (!pmd_write(*pmd) && gup_must_unshare(vma, flags, page)) 1497a7f22660SDavid Hildenbrand return ERR_PTR(-EMLINK); 1498a7f22660SDavid Hildenbrand 1499b6a2619cSDavid Hildenbrand VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && 1500b6a2619cSDavid Hildenbrand !PageAnonExclusive(page), page); 1501b6a2619cSDavid Hildenbrand 15020f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 15030f089235SLogan Gunthorpe if (ret) 15040f089235SLogan Gunthorpe return ERR_PTR(ret); 15053faa52c0SJohn Hubbard 15063565fce3SDan Williams if (flags & FOLL_TOUCH) 1507a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 15083faa52c0SJohn Hubbard 150971e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1510ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 151171e3aac0SAndrea Arcangeli 151271e3aac0SAndrea Arcangeli return page; 151371e3aac0SAndrea Arcangeli } 151471e3aac0SAndrea Arcangeli 1515d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 15165db4f15cSYang Shi vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) 1517d10e63f2SMel Gorman { 151882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1519c5b5a3ddSYang Shi pmd_t oldpmd = vmf->orig_pmd; 1520c5b5a3ddSYang Shi pmd_t pmd; 1521667ffc31SKefeng Wang struct folio *folio; 152282b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 1523667ffc31SKefeng Wang int nid = NUMA_NO_NODE; 152433024536SHuang Ying int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); 15256a56ccbcSDavid Hildenbrand bool migrated = false, writable = false; 15266688cc05SPeter Zijlstra int flags = 0; 1527d10e63f2SMel Gorman 152882b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1529c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 153082b0f8c3SJan Kara spin_unlock(vmf->ptl); 1531de466bd6SMel Gorman goto out; 1532de466bd6SMel Gorman } 1533de466bd6SMel Gorman 1534c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 15356a56ccbcSDavid Hildenbrand 15366a56ccbcSDavid Hildenbrand /* 15376a56ccbcSDavid Hildenbrand * Detect now whether the PMD could be writable; this information 15386a56ccbcSDavid Hildenbrand * is only valid while holding the PT lock. 15396a56ccbcSDavid Hildenbrand */ 15406a56ccbcSDavid Hildenbrand writable = pmd_write(pmd); 15416a56ccbcSDavid Hildenbrand if (!writable && vma_wants_manual_pte_write_upgrade(vma) && 15426a56ccbcSDavid Hildenbrand can_change_pmd_writable(vma, vmf->address, pmd)) 15436a56ccbcSDavid Hildenbrand writable = true; 15446a56ccbcSDavid Hildenbrand 1545667ffc31SKefeng Wang folio = vm_normal_folio_pmd(vma, haddr, pmd); 1546667ffc31SKefeng Wang if (!folio) 1547c5b5a3ddSYang Shi goto out_map; 1548c5b5a3ddSYang Shi 1549c5b5a3ddSYang Shi /* See similar comment in do_numa_page for explanation */ 15506a56ccbcSDavid Hildenbrand if (!writable) 1551c5b5a3ddSYang Shi flags |= TNF_NO_GROUP; 1552c5b5a3ddSYang Shi 1553667ffc31SKefeng Wang nid = folio_nid(folio); 155433024536SHuang Ying /* 155533024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 155633024536SHuang Ying * to record page access time. So use default value. 155733024536SHuang Ying */ 1558667ffc31SKefeng Wang if (node_is_toptier(nid)) 1559667ffc31SKefeng Wang last_cpupid = page_cpupid_last(&folio->page); 1560cda6d936SKefeng Wang target_nid = numa_migrate_prep(folio, vma, haddr, nid, &flags); 1561c5b5a3ddSYang Shi if (target_nid == NUMA_NO_NODE) { 1562667ffc31SKefeng Wang folio_put(folio); 1563c5b5a3ddSYang Shi goto out_map; 1564c5b5a3ddSYang Shi } 1565c5b5a3ddSYang Shi 156682b0f8c3SJan Kara spin_unlock(vmf->ptl); 15676a56ccbcSDavid Hildenbrand writable = false; 15688b1b436dSPeter Zijlstra 1569667ffc31SKefeng Wang migrated = migrate_misplaced_folio(folio, vma, target_nid); 15706688cc05SPeter Zijlstra if (migrated) { 15716688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 1572667ffc31SKefeng Wang nid = target_nid; 1573c5b5a3ddSYang Shi } else { 1574074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1575c5b5a3ddSYang Shi vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1576c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 157782b0f8c3SJan Kara spin_unlock(vmf->ptl); 1578c5b5a3ddSYang Shi goto out; 1579c5b5a3ddSYang Shi } 1580c5b5a3ddSYang Shi goto out_map; 1581c5b5a3ddSYang Shi } 1582b8916634SMel Gorman 1583b8916634SMel Gorman out: 1584667ffc31SKefeng Wang if (nid != NUMA_NO_NODE) 1585667ffc31SKefeng Wang task_numa_fault(last_cpupid, nid, HPAGE_PMD_NR, flags); 15868191acbdSMel Gorman 1587d10e63f2SMel Gorman return 0; 1588c5b5a3ddSYang Shi 1589c5b5a3ddSYang Shi out_map: 1590c5b5a3ddSYang Shi /* Restore the PMD */ 1591c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 1592c5b5a3ddSYang Shi pmd = pmd_mkyoung(pmd); 15936a56ccbcSDavid Hildenbrand if (writable) 1594161e393cSRick Edgecombe pmd = pmd_mkwrite(pmd, vma); 1595c5b5a3ddSYang Shi set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 1596c5b5a3ddSYang Shi update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1597c5b5a3ddSYang Shi spin_unlock(vmf->ptl); 1598c5b5a3ddSYang Shi goto out; 1599d10e63f2SMel Gorman } 1600d10e63f2SMel Gorman 1601319904adSHuang Ying /* 1602319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1603319904adSHuang Ying * Otherwise, return false. 1604319904adSHuang Ying */ 1605319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1606b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1607b8d3c4c3SMinchan Kim { 1608b8d3c4c3SMinchan Kim spinlock_t *ptl; 1609b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1610fc986a38SKefeng Wang struct folio *folio; 1611b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1612319904adSHuang Ying bool ret = false; 1613b8d3c4c3SMinchan Kim 1614ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 161507e32661SAneesh Kumar K.V 1616b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1617b6ec57f4SKirill A. Shutemov if (!ptl) 161825eedabeSLinus Torvalds goto out_unlocked; 1619b8d3c4c3SMinchan Kim 1620b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1621319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1622b8d3c4c3SMinchan Kim goto out; 1623b8d3c4c3SMinchan Kim 162484c3fc4eSZi Yan if (unlikely(!pmd_present(orig_pmd))) { 162584c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 162684c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 162784c3fc4eSZi Yan goto out; 162884c3fc4eSZi Yan } 162984c3fc4eSZi Yan 1630fc986a38SKefeng Wang folio = pfn_folio(pmd_pfn(orig_pmd)); 1631b8d3c4c3SMinchan Kim /* 1632fc986a38SKefeng Wang * If other processes are mapping this folio, we couldn't discard 1633fc986a38SKefeng Wang * the folio unless they all do MADV_FREE so let's skip the folio. 1634b8d3c4c3SMinchan Kim */ 163520b18aadSYin Fengwei if (folio_estimated_sharers(folio) != 1) 1636b8d3c4c3SMinchan Kim goto out; 1637b8d3c4c3SMinchan Kim 1638fc986a38SKefeng Wang if (!folio_trylock(folio)) 1639b8d3c4c3SMinchan Kim goto out; 1640b8d3c4c3SMinchan Kim 1641b8d3c4c3SMinchan Kim /* 1642b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1643b8d3c4c3SMinchan Kim * will deactivate only them. 1644b8d3c4c3SMinchan Kim */ 1645b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1646fc986a38SKefeng Wang folio_get(folio); 1647b8d3c4c3SMinchan Kim spin_unlock(ptl); 1648fc986a38SKefeng Wang split_folio(folio); 1649fc986a38SKefeng Wang folio_unlock(folio); 1650fc986a38SKefeng Wang folio_put(folio); 1651b8d3c4c3SMinchan Kim goto out_unlocked; 1652b8d3c4c3SMinchan Kim } 1653b8d3c4c3SMinchan Kim 1654fc986a38SKefeng Wang if (folio_test_dirty(folio)) 1655fc986a38SKefeng Wang folio_clear_dirty(folio); 1656fc986a38SKefeng Wang folio_unlock(folio); 1657b8d3c4c3SMinchan Kim 1658b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 165958ceeb6bSKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1660b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1661b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1662b8d3c4c3SMinchan Kim 1663b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1664b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1665b8d3c4c3SMinchan Kim } 1666802a3a92SShaohua Li 16676a6fe9ebSKefeng Wang folio_mark_lazyfree(folio); 1668319904adSHuang Ying ret = true; 1669b8d3c4c3SMinchan Kim out: 1670b8d3c4c3SMinchan Kim spin_unlock(ptl); 1671b8d3c4c3SMinchan Kim out_unlocked: 1672b8d3c4c3SMinchan Kim return ret; 1673b8d3c4c3SMinchan Kim } 1674b8d3c4c3SMinchan Kim 1675953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1676953c66c2SAneesh Kumar K.V { 1677953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1678953c66c2SAneesh Kumar K.V 1679953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1680953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1681c4812909SKirill A. Shutemov mm_dec_nr_ptes(mm); 1682953c66c2SAneesh Kumar K.V } 1683953c66c2SAneesh Kumar K.V 168471e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1685f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 168671e3aac0SAndrea Arcangeli { 1687f5c8ad47SDavid Miller pmd_t orig_pmd; 1688da146769SKirill A. Shutemov spinlock_t *ptl; 1689da146769SKirill A. Shutemov 1690ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 169107e32661SAneesh Kumar K.V 1692b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1693b6ec57f4SKirill A. Shutemov if (!ptl) 1694da146769SKirill A. Shutemov return 0; 1695a6bf2bb0SAneesh Kumar K.V /* 1696a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 16978809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1698a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1699a6bf2bb0SAneesh Kumar K.V * operations. 1700a6bf2bb0SAneesh Kumar K.V */ 170193a98695SAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, 1702fcbe08d6SMartin Schwidefsky tlb->fullmm); 1703e5136e87SRick Edgecombe arch_check_zapped_pmd(vma, orig_pmd); 1704f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 17052484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 17063b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) 17073b6521f5SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 17084897c765SMatthew Wilcox spin_unlock(ptl); 1709da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1710c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1711bf929152SKirill A. Shutemov spin_unlock(ptl); 1712479f0abbSKirill A. Shutemov } else { 1713616b8371SZi Yan struct page *page = NULL; 1714616b8371SZi Yan int flush_needed = 1; 1715616b8371SZi Yan 1716616b8371SZi Yan if (pmd_present(orig_pmd)) { 1717616b8371SZi Yan page = pmd_page(orig_pmd); 1718cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 1719309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1720309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1721616b8371SZi Yan } else if (thp_migration_supported()) { 1722616b8371SZi Yan swp_entry_t entry; 1723616b8371SZi Yan 1724616b8371SZi Yan VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); 1725616b8371SZi Yan entry = pmd_to_swp_entry(orig_pmd); 1726af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1727616b8371SZi Yan flush_needed = 0; 1728616b8371SZi Yan } else 1729616b8371SZi Yan WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); 1730616b8371SZi Yan 1731b5072380SKirill A. Shutemov if (PageAnon(page)) { 1732c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1733b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1734b5072380SKirill A. Shutemov } else { 1735953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1736953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1737fadae295SYang Shi add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); 1738b5072380SKirill A. Shutemov } 1739616b8371SZi Yan 1740bf929152SKirill A. Shutemov spin_unlock(ptl); 1741616b8371SZi Yan if (flush_needed) 1742e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1743479f0abbSKirill A. Shutemov } 1744da146769SKirill A. Shutemov return 1; 174571e3aac0SAndrea Arcangeli } 174671e3aac0SAndrea Arcangeli 17471dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 17481dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 17491dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 17501dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 17511dd38b6cSAneesh Kumar K.V { 17521dd38b6cSAneesh Kumar K.V /* 17531dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 17541dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 17551dd38b6cSAneesh Kumar K.V * 17561dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 17571dd38b6cSAneesh Kumar K.V */ 17581dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 17591dd38b6cSAneesh Kumar K.V } 17601dd38b6cSAneesh Kumar K.V #endif 17611dd38b6cSAneesh Kumar K.V 1762ab6e3d09SNaoya Horiguchi static pmd_t move_soft_dirty_pmd(pmd_t pmd) 1763ab6e3d09SNaoya Horiguchi { 1764ab6e3d09SNaoya Horiguchi #ifdef CONFIG_MEM_SOFT_DIRTY 1765ab6e3d09SNaoya Horiguchi if (unlikely(is_pmd_migration_entry(pmd))) 1766ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 1767ab6e3d09SNaoya Horiguchi else if (pmd_present(pmd)) 1768ab6e3d09SNaoya Horiguchi pmd = pmd_mksoft_dirty(pmd); 1769ab6e3d09SNaoya Horiguchi #endif 1770ab6e3d09SNaoya Horiguchi return pmd; 1771ab6e3d09SNaoya Horiguchi } 1772ab6e3d09SNaoya Horiguchi 1773bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 1774b8aa9d9dSWei Yang unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) 177537a1c49aSAndrea Arcangeli { 1776bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 177737a1c49aSAndrea Arcangeli pmd_t pmd; 177837a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 17795d190420SAaron Lu bool force_flush = false; 178037a1c49aSAndrea Arcangeli 178137a1c49aSAndrea Arcangeli /* 178237a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 1783a5be621eSHugh Dickins * should have released it; but move_page_tables() might have already 1784a5be621eSHugh Dickins * inserted a page table, if racing against shmem/file collapse. 178537a1c49aSAndrea Arcangeli */ 1786a5be621eSHugh Dickins if (!pmd_none(*new_pmd)) { 178737a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 17884b471e88SKirill A. Shutemov return false; 178937a1c49aSAndrea Arcangeli } 179037a1c49aSAndrea Arcangeli 1791bf929152SKirill A. Shutemov /* 1792bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1793c1e8d7c6SMichel Lespinasse * ptlocks because exclusive mmap_lock prevents deadlock. 1794bf929152SKirill A. Shutemov */ 1795b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1796b6ec57f4SKirill A. Shutemov if (old_ptl) { 1797bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1798bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1799bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 18008809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1801eb66ae03SLinus Torvalds if (pmd_present(pmd)) 1802a2ce2666SAaron Lu force_flush = true; 180337a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 18043592806cSKirill A. Shutemov 18051dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1806b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 18073592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 18083592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 18093592806cSKirill A. Shutemov } 1810ab6e3d09SNaoya Horiguchi pmd = move_soft_dirty_pmd(pmd); 1811ab6e3d09SNaoya Horiguchi set_pmd_at(mm, new_addr, new_pmd, pmd); 18125d190420SAaron Lu if (force_flush) 18137c38f181SMiaohe Lin flush_pmd_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 1814eb66ae03SLinus Torvalds if (new_ptl != old_ptl) 1815eb66ae03SLinus Torvalds spin_unlock(new_ptl); 1816bf929152SKirill A. Shutemov spin_unlock(old_ptl); 18174b471e88SKirill A. Shutemov return true; 181837a1c49aSAndrea Arcangeli } 18194b471e88SKirill A. Shutemov return false; 182037a1c49aSAndrea Arcangeli } 182137a1c49aSAndrea Arcangeli 1822f123d74aSMel Gorman /* 1823f123d74aSMel Gorman * Returns 1824f123d74aSMel Gorman * - 0 if PMD could not be locked 1825f0953a1bSIngo Molnar * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary 1826e346e668SYang Shi * or if prot_numa but THP migration is not supported 1827f0953a1bSIngo Molnar * - HPAGE_PMD_NR if protections changed and TLB flush necessary 1828f123d74aSMel Gorman */ 18294a18419fSNadav Amit int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 18304a18419fSNadav Amit pmd_t *pmd, unsigned long addr, pgprot_t newprot, 18314a18419fSNadav Amit unsigned long cp_flags) 1832cd7548abSJohannes Weiner { 1833cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1834bf929152SKirill A. Shutemov spinlock_t *ptl; 1835c9fe6656SNadav Amit pmd_t oldpmd, entry; 183658705444SPeter Xu bool prot_numa = cp_flags & MM_CP_PROT_NUMA; 1837292924b2SPeter Xu bool uffd_wp = cp_flags & MM_CP_UFFD_WP; 1838292924b2SPeter Xu bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; 18396a56ccbcSDavid Hildenbrand int ret = 1; 1840cd7548abSJohannes Weiner 18414a18419fSNadav Amit tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 18424a18419fSNadav Amit 1843e346e668SYang Shi if (prot_numa && !thp_migration_supported()) 1844e346e668SYang Shi return 1; 1845e346e668SYang Shi 1846b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 18470a85e51dSKirill A. Shutemov if (!ptl) 18480a85e51dSKirill A. Shutemov return 0; 18490a85e51dSKirill A. Shutemov 185084c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 185184c3fc4eSZi Yan if (is_swap_pmd(*pmd)) { 185284c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(*pmd); 18536c287605SDavid Hildenbrand struct page *page = pfn_swap_entry_to_page(entry); 185424bf08c4SDavid Hildenbrand pmd_t newpmd; 185584c3fc4eSZi Yan 185684c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd)); 18574dd845b5SAlistair Popple if (is_writable_migration_entry(entry)) { 185884c3fc4eSZi Yan /* 185984c3fc4eSZi Yan * A protection check is difficult so 186084c3fc4eSZi Yan * just be safe and disable write 186184c3fc4eSZi Yan */ 18626c287605SDavid Hildenbrand if (PageAnon(page)) 18636c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(swp_offset(entry)); 18646c287605SDavid Hildenbrand else 18656c287605SDavid Hildenbrand entry = make_readable_migration_entry(swp_offset(entry)); 186684c3fc4eSZi Yan newpmd = swp_entry_to_pmd(entry); 1867ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pmd)) 1868ab6e3d09SNaoya Horiguchi newpmd = pmd_swp_mksoft_dirty(newpmd); 186924bf08c4SDavid Hildenbrand } else { 187024bf08c4SDavid Hildenbrand newpmd = *pmd; 187184c3fc4eSZi Yan } 187224bf08c4SDavid Hildenbrand 187324bf08c4SDavid Hildenbrand if (uffd_wp) 187424bf08c4SDavid Hildenbrand newpmd = pmd_swp_mkuffd_wp(newpmd); 187524bf08c4SDavid Hildenbrand else if (uffd_wp_resolve) 187624bf08c4SDavid Hildenbrand newpmd = pmd_swp_clear_uffd_wp(newpmd); 187724bf08c4SDavid Hildenbrand if (!pmd_same(*pmd, newpmd)) 187824bf08c4SDavid Hildenbrand set_pmd_at(mm, addr, pmd, newpmd); 187984c3fc4eSZi Yan goto unlock; 188084c3fc4eSZi Yan } 188184c3fc4eSZi Yan #endif 188284c3fc4eSZi Yan 1883a1a3a2fcSHuang Ying if (prot_numa) { 1884a1a3a2fcSHuang Ying struct page *page; 188533024536SHuang Ying bool toptier; 1886e944fd67SMel Gorman /* 1887e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1888e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1889e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1890e944fd67SMel Gorman */ 1891a1a3a2fcSHuang Ying if (is_huge_zero_pmd(*pmd)) 18920a85e51dSKirill A. Shutemov goto unlock; 1893e944fd67SMel Gorman 1894a1a3a2fcSHuang Ying if (pmd_protnone(*pmd)) 18950a85e51dSKirill A. Shutemov goto unlock; 18960a85e51dSKirill A. Shutemov 1897a1a3a2fcSHuang Ying page = pmd_page(*pmd); 189833024536SHuang Ying toptier = node_is_toptier(page_to_nid(page)); 1899a1a3a2fcSHuang Ying /* 1900a1a3a2fcSHuang Ying * Skip scanning top tier node if normal numa 1901a1a3a2fcSHuang Ying * balancing is disabled 1902a1a3a2fcSHuang Ying */ 1903a1a3a2fcSHuang Ying if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && 190433024536SHuang Ying toptier) 1905a1a3a2fcSHuang Ying goto unlock; 190633024536SHuang Ying 190733024536SHuang Ying if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && 190833024536SHuang Ying !toptier) 190933024536SHuang Ying xchg_page_access_time(page, jiffies_to_msecs(jiffies)); 1910a1a3a2fcSHuang Ying } 1911ced10803SKirill A. Shutemov /* 19123e4e28c5SMichel Lespinasse * In case prot_numa, we are under mmap_read_lock(mm). It's critical 1913ced10803SKirill A. Shutemov * to not clear pmd intermittently to avoid race with MADV_DONTNEED 19143e4e28c5SMichel Lespinasse * which is also under mmap_read_lock(mm): 1915ced10803SKirill A. Shutemov * 1916ced10803SKirill A. Shutemov * CPU0: CPU1: 1917ced10803SKirill A. Shutemov * change_huge_pmd(prot_numa=1) 1918ced10803SKirill A. Shutemov * pmdp_huge_get_and_clear_notify() 1919ced10803SKirill A. Shutemov * madvise_dontneed() 1920ced10803SKirill A. Shutemov * zap_pmd_range() 1921ced10803SKirill A. Shutemov * pmd_trans_huge(*pmd) == 0 (without ptl) 1922ced10803SKirill A. Shutemov * // skip the pmd 1923ced10803SKirill A. Shutemov * set_pmd_at(); 1924ced10803SKirill A. Shutemov * // pmd is re-established 1925ced10803SKirill A. Shutemov * 1926ced10803SKirill A. Shutemov * The race makes MADV_DONTNEED miss the huge pmd and don't clear it 1927ced10803SKirill A. Shutemov * which may break userspace. 1928ced10803SKirill A. Shutemov * 19294f831457SNadav Amit * pmdp_invalidate_ad() is required to make sure we don't miss 1930ced10803SKirill A. Shutemov * dirty/young flags set by hardware. 1931ced10803SKirill A. Shutemov */ 19324f831457SNadav Amit oldpmd = pmdp_invalidate_ad(vma, addr, pmd); 1933ced10803SKirill A. Shutemov 1934c9fe6656SNadav Amit entry = pmd_modify(oldpmd, newprot); 1935f1eb1bacSPeter Xu if (uffd_wp) 1936292924b2SPeter Xu entry = pmd_mkuffd_wp(entry); 1937f1eb1bacSPeter Xu else if (uffd_wp_resolve) 1938292924b2SPeter Xu /* 1939292924b2SPeter Xu * Leave the write bit to be handled by PF interrupt 1940292924b2SPeter Xu * handler, then things like COW could be properly 1941292924b2SPeter Xu * handled. 1942292924b2SPeter Xu */ 1943292924b2SPeter Xu entry = pmd_clear_uffd_wp(entry); 1944c27f479eSDavid Hildenbrand 1945c27f479eSDavid Hildenbrand /* See change_pte_range(). */ 1946c27f479eSDavid Hildenbrand if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && !pmd_write(entry) && 1947c27f479eSDavid Hildenbrand can_change_pmd_writable(vma, addr, entry)) 1948161e393cSRick Edgecombe entry = pmd_mkwrite(entry, vma); 1949c27f479eSDavid Hildenbrand 1950f123d74aSMel Gorman ret = HPAGE_PMD_NR; 195156eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 19524a18419fSNadav Amit 1953c9fe6656SNadav Amit if (huge_pmd_needs_flush(oldpmd, entry)) 19544a18419fSNadav Amit tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); 19550a85e51dSKirill A. Shutemov unlock: 1956bf929152SKirill A. Shutemov spin_unlock(ptl); 1957cd7548abSJohannes Weiner return ret; 1958cd7548abSJohannes Weiner } 1959cd7548abSJohannes Weiner 1960025c5b24SNaoya Horiguchi /* 19618f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 1962025c5b24SNaoya Horiguchi * 19638f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 19648f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 1965025c5b24SNaoya Horiguchi */ 1966b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1967025c5b24SNaoya Horiguchi { 1968b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 1969b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 197084c3fc4eSZi Yan if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || 197184c3fc4eSZi Yan pmd_devmap(*pmd))) 1972b6ec57f4SKirill A. Shutemov return ptl; 1973b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 1974b6ec57f4SKirill A. Shutemov return NULL; 1975025c5b24SNaoya Horiguchi } 1976025c5b24SNaoya Horiguchi 1977a00cc7d9SMatthew Wilcox /* 1978d965e390SMiaohe Lin * Returns page table lock pointer if a given pud maps a thp, NULL otherwise. 1979a00cc7d9SMatthew Wilcox * 1980d965e390SMiaohe Lin * Note that if it returns page table lock pointer, this routine returns without 1981d965e390SMiaohe Lin * unlocking page table lock. So callers must unlock it. 1982a00cc7d9SMatthew Wilcox */ 1983a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 1984a00cc7d9SMatthew Wilcox { 1985a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1986a00cc7d9SMatthew Wilcox 1987a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 1988a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 1989a00cc7d9SMatthew Wilcox return ptl; 1990a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1991a00cc7d9SMatthew Wilcox return NULL; 1992a00cc7d9SMatthew Wilcox } 1993a00cc7d9SMatthew Wilcox 1994a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1995a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 1996a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 1997a00cc7d9SMatthew Wilcox { 1998a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1999a00cc7d9SMatthew Wilcox 2000a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 2001a00cc7d9SMatthew Wilcox if (!ptl) 2002a00cc7d9SMatthew Wilcox return 0; 200374929079SMiaohe Lin 2004f32928abSAneesh Kumar K.V pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm); 2005a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 20062484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 2007a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2008a00cc7d9SMatthew Wilcox /* No zero page support yet */ 2009a00cc7d9SMatthew Wilcox } else { 2010a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 2011a00cc7d9SMatthew Wilcox BUG(); 2012a00cc7d9SMatthew Wilcox } 2013a00cc7d9SMatthew Wilcox return 1; 2014a00cc7d9SMatthew Wilcox } 2015a00cc7d9SMatthew Wilcox 2016a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 2017a00cc7d9SMatthew Wilcox unsigned long haddr) 2018a00cc7d9SMatthew Wilcox { 2019a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 2020a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2021a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 2022a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 2023a00cc7d9SMatthew Wilcox 2024ce9311cfSYisheng Xie count_vm_event(THP_SPLIT_PUD); 2025a00cc7d9SMatthew Wilcox 2026ec8832d0SAlistair Popple pudp_huge_clear_flush(vma, haddr, pud); 2027a00cc7d9SMatthew Wilcox } 2028a00cc7d9SMatthew Wilcox 2029a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 2030a00cc7d9SMatthew Wilcox unsigned long address) 2031a00cc7d9SMatthew Wilcox { 2032a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2033ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2034a00cc7d9SMatthew Wilcox 20357d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 20366f4f13e8SJérôme Glisse address & HPAGE_PUD_MASK, 2037ac46d4f3SJérôme Glisse (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); 2038ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2039ac46d4f3SJérôme Glisse ptl = pud_lock(vma->vm_mm, pud); 2040a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 2041a00cc7d9SMatthew Wilcox goto out; 2042ac46d4f3SJérôme Glisse __split_huge_pud_locked(vma, pud, range.start); 2043a00cc7d9SMatthew Wilcox 2044a00cc7d9SMatthew Wilcox out: 2045a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2046ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 2047a00cc7d9SMatthew Wilcox } 2048a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 2049a00cc7d9SMatthew Wilcox 2050eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2051eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2052eef1b3baSKirill A. Shutemov { 2053eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2054eef1b3baSKirill A. Shutemov pgtable_t pgtable; 205542b2af2cSDavid Hildenbrand pmd_t _pmd, old_pmd; 2056c9c1ee20SHugh Dickins unsigned long addr; 2057c9c1ee20SHugh Dickins pte_t *pte; 2058eef1b3baSKirill A. Shutemov int i; 2059eef1b3baSKirill A. Shutemov 20600f10851eSJérôme Glisse /* 20610f10851eSJérôme Glisse * Leave pmd empty until pte is filled note that it is fine to delay 20620f10851eSJérôme Glisse * notification until mmu_notifier_invalidate_range_end() as we are 20630f10851eSJérôme Glisse * replacing a zero pmd write protected page with a zero pte write 20640f10851eSJérôme Glisse * protected page. 20650f10851eSJérôme Glisse * 2066ee65728eSMike Rapoport * See Documentation/mm/mmu_notifier.rst 20670f10851eSJérôme Glisse */ 206842b2af2cSDavid Hildenbrand old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); 2069eef1b3baSKirill A. Shutemov 2070eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2071eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2072eef1b3baSKirill A. Shutemov 2073c9c1ee20SHugh Dickins pte = pte_offset_map(&_pmd, haddr); 2074c9c1ee20SHugh Dickins VM_BUG_ON(!pte); 2075c9c1ee20SHugh Dickins for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2076c9c1ee20SHugh Dickins pte_t entry; 2077c9c1ee20SHugh Dickins 2078c9c1ee20SHugh Dickins entry = pfn_pte(my_zero_pfn(addr), vma->vm_page_prot); 2079eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 208042b2af2cSDavid Hildenbrand if (pmd_uffd_wp(old_pmd)) 208142b2af2cSDavid Hildenbrand entry = pte_mkuffd_wp(entry); 2082c33c7948SRyan Roberts VM_BUG_ON(!pte_none(ptep_get(pte))); 2083c9c1ee20SHugh Dickins set_pte_at(mm, addr, pte, entry); 2084c9c1ee20SHugh Dickins pte++; 2085eef1b3baSKirill A. Shutemov } 2086c9c1ee20SHugh Dickins pte_unmap(pte - 1); 2087eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2088eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2089eef1b3baSKirill A. Shutemov } 2090eef1b3baSKirill A. Shutemov 2091eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 2092ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 2093eef1b3baSKirill A. Shutemov { 2094eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2095eef1b3baSKirill A. Shutemov struct page *page; 2096eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2097423ac9afSAneesh Kumar K.V pmd_t old_pmd, _pmd; 2098292924b2SPeter Xu bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; 20990ccf7f16SPeter Xu bool anon_exclusive = false, dirty = false; 21002ac015e2SKirill A. Shutemov unsigned long addr; 2101c9c1ee20SHugh Dickins pte_t *pte; 2102eef1b3baSKirill A. Shutemov int i; 2103eef1b3baSKirill A. Shutemov 2104eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 2105eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2106eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 210784c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) 210884c3fc4eSZi Yan && !pmd_devmap(*pmd)); 2109eef1b3baSKirill A. Shutemov 2110eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 2111eef1b3baSKirill A. Shutemov 2112d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 2113ec8832d0SAlistair Popple old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); 2114953c66c2SAneesh Kumar K.V /* 2115953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 2116953c66c2SAneesh Kumar K.V * just go ahead and zap it 2117953c66c2SAneesh Kumar K.V */ 2118953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 2119953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 21202484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) 2121d21b9e57SKirill A. Shutemov return; 212299fa8a48SHugh Dickins if (unlikely(is_pmd_migration_entry(old_pmd))) { 212399fa8a48SHugh Dickins swp_entry_t entry; 212499fa8a48SHugh Dickins 212599fa8a48SHugh Dickins entry = pmd_to_swp_entry(old_pmd); 2126af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 212799fa8a48SHugh Dickins } else { 212899fa8a48SHugh Dickins page = pmd_page(old_pmd); 212999fa8a48SHugh Dickins if (!PageDirty(page) && pmd_dirty(old_pmd)) 2130e1f1b157SHugh Dickins set_page_dirty(page); 213199fa8a48SHugh Dickins if (!PageReferenced(page) && pmd_young(old_pmd)) 2132d21b9e57SKirill A. Shutemov SetPageReferenced(page); 2133cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 2134d21b9e57SKirill A. Shutemov put_page(page); 213599fa8a48SHugh Dickins } 2136fadae295SYang Shi add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); 2137eef1b3baSKirill A. Shutemov return; 213899fa8a48SHugh Dickins } 213999fa8a48SHugh Dickins 21403b77e8c8SHugh Dickins if (is_huge_zero_pmd(*pmd)) { 21414645b9feSJérôme Glisse /* 21424645b9feSJérôme Glisse * FIXME: Do we want to invalidate secondary mmu by calling 21431af5a810SAlistair Popple * mmu_notifier_arch_invalidate_secondary_tlbs() see comments below 21441af5a810SAlistair Popple * inside __split_huge_pmd() ? 21454645b9feSJérôme Glisse * 21464645b9feSJérôme Glisse * We are going from a zero huge page write protected to zero 21474645b9feSJérôme Glisse * small page also write protected so it does not seems useful 21484645b9feSJérôme Glisse * to invalidate secondary mmu at this time. 21494645b9feSJérôme Glisse */ 2150eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 2151eef1b3baSKirill A. Shutemov } 2152eef1b3baSKirill A. Shutemov 2153423ac9afSAneesh Kumar K.V /* 2154423ac9afSAneesh Kumar K.V * Up to this point the pmd is present and huge and userland has the 2155423ac9afSAneesh Kumar K.V * whole access to the hugepage during the split (which happens in 2156423ac9afSAneesh Kumar K.V * place). If we overwrite the pmd with the not-huge version pointing 2157423ac9afSAneesh Kumar K.V * to the pte here (which of course we could if all CPUs were bug 2158423ac9afSAneesh Kumar K.V * free), userland could trigger a small page size TLB miss on the 2159423ac9afSAneesh Kumar K.V * small sized TLB while the hugepage TLB entry is still established in 2160423ac9afSAneesh Kumar K.V * the huge TLB. Some CPU doesn't like that. 216142742d9bSAlexander A. Klimov * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum 216242742d9bSAlexander A. Klimov * 383 on page 105. Intel should be safe but is also warns that it's 2163423ac9afSAneesh Kumar K.V * only safe if the permission and cache attributes of the two entries 2164423ac9afSAneesh Kumar K.V * loaded in the two TLB is identical (which should be the case here). 2165423ac9afSAneesh Kumar K.V * But it is generally safer to never allow small and huge TLB entries 2166423ac9afSAneesh Kumar K.V * for the same virtual address to be loaded simultaneously. So instead 2167423ac9afSAneesh Kumar K.V * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2168423ac9afSAneesh Kumar K.V * current pmd notpresent (atomically because here the pmd_trans_huge 2169423ac9afSAneesh Kumar K.V * must remain set at all times on the pmd until the split is complete 2170423ac9afSAneesh Kumar K.V * for this pmd), then we flush the SMP TLB and finally we write the 2171423ac9afSAneesh Kumar K.V * non-huge version of the pmd entry with pmd_populate. 2172423ac9afSAneesh Kumar K.V */ 2173423ac9afSAneesh Kumar K.V old_pmd = pmdp_invalidate(vma, haddr, pmd); 2174423ac9afSAneesh Kumar K.V 2175423ac9afSAneesh Kumar K.V pmd_migration = is_pmd_migration_entry(old_pmd); 21762e83ee1dSPeter Xu if (unlikely(pmd_migration)) { 217784c3fc4eSZi Yan swp_entry_t entry; 217884c3fc4eSZi Yan 2179423ac9afSAneesh Kumar K.V entry = pmd_to_swp_entry(old_pmd); 2180af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 21814dd845b5SAlistair Popple write = is_writable_migration_entry(entry); 21826c287605SDavid Hildenbrand if (PageAnon(page)) 21836c287605SDavid Hildenbrand anon_exclusive = is_readable_exclusive_migration_entry(entry); 21842e346877SPeter Xu young = is_migration_entry_young(entry); 21852e346877SPeter Xu dirty = is_migration_entry_dirty(entry); 21862e83ee1dSPeter Xu soft_dirty = pmd_swp_soft_dirty(old_pmd); 2187f45ec5ffSPeter Xu uffd_wp = pmd_swp_uffd_wp(old_pmd); 21882e83ee1dSPeter Xu } else { 2189423ac9afSAneesh Kumar K.V page = pmd_page(old_pmd); 21900ccf7f16SPeter Xu if (pmd_dirty(old_pmd)) { 21910ccf7f16SPeter Xu dirty = true; 2192423ac9afSAneesh Kumar K.V SetPageDirty(page); 21930ccf7f16SPeter Xu } 2194423ac9afSAneesh Kumar K.V write = pmd_write(old_pmd); 2195423ac9afSAneesh Kumar K.V young = pmd_young(old_pmd); 2196423ac9afSAneesh Kumar K.V soft_dirty = pmd_soft_dirty(old_pmd); 2197292924b2SPeter Xu uffd_wp = pmd_uffd_wp(old_pmd); 21986c287605SDavid Hildenbrand 21992e83ee1dSPeter Xu VM_BUG_ON_PAGE(!page_count(page), page); 22006c287605SDavid Hildenbrand 22016c287605SDavid Hildenbrand /* 22026c287605SDavid Hildenbrand * Without "freeze", we'll simply split the PMD, propagating the 22036c287605SDavid Hildenbrand * PageAnonExclusive() flag for each PTE by setting it for 22046c287605SDavid Hildenbrand * each subpage -- no need to (temporarily) clear. 22056c287605SDavid Hildenbrand * 22066c287605SDavid Hildenbrand * With "freeze" we want to replace mapped pages by 22076c287605SDavid Hildenbrand * migration entries right away. This is only possible if we 22086c287605SDavid Hildenbrand * managed to clear PageAnonExclusive() -- see 22096c287605SDavid Hildenbrand * set_pmd_migration_entry(). 22106c287605SDavid Hildenbrand * 22116c287605SDavid Hildenbrand * In case we cannot clear PageAnonExclusive(), split the PMD 22126c287605SDavid Hildenbrand * only and let try_to_migrate_one() fail later. 2213088b8aa5SDavid Hildenbrand * 2214088b8aa5SDavid Hildenbrand * See page_try_share_anon_rmap(): invalidate PMD first. 22156c287605SDavid Hildenbrand */ 22166c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 22176c287605SDavid Hildenbrand if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) 22186c287605SDavid Hildenbrand freeze = false; 221996d82debSHugh Dickins if (!freeze) 222096d82debSHugh Dickins page_ref_add(page, HPAGE_PMD_NR - 1); 22219d84604bSHugh Dickins } 2222eef1b3baSKirill A. Shutemov 2223423ac9afSAneesh Kumar K.V /* 2224423ac9afSAneesh Kumar K.V * Withdraw the table only after we mark the pmd entry invalid. 2225423ac9afSAneesh Kumar K.V * This's critical for some architectures (Power). 2226423ac9afSAneesh Kumar K.V */ 2227eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2228eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2229eef1b3baSKirill A. Shutemov 2230c9c1ee20SHugh Dickins pte = pte_offset_map(&_pmd, haddr); 2231c9c1ee20SHugh Dickins VM_BUG_ON(!pte); 22322ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2233c9c1ee20SHugh Dickins pte_t entry; 2234eef1b3baSKirill A. Shutemov /* 2235eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 2236eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 2237eef1b3baSKirill A. Shutemov * permissions across VMAs. 2238eef1b3baSKirill A. Shutemov */ 223984c3fc4eSZi Yan if (freeze || pmd_migration) { 2240ba988280SKirill A. Shutemov swp_entry_t swp_entry; 22414dd845b5SAlistair Popple if (write) 22424dd845b5SAlistair Popple swp_entry = make_writable_migration_entry( 22434dd845b5SAlistair Popple page_to_pfn(page + i)); 22446c287605SDavid Hildenbrand else if (anon_exclusive) 22456c287605SDavid Hildenbrand swp_entry = make_readable_exclusive_migration_entry( 22466c287605SDavid Hildenbrand page_to_pfn(page + i)); 22474dd845b5SAlistair Popple else 22484dd845b5SAlistair Popple swp_entry = make_readable_migration_entry( 22494dd845b5SAlistair Popple page_to_pfn(page + i)); 22502e346877SPeter Xu if (young) 22512e346877SPeter Xu swp_entry = make_migration_entry_young(swp_entry); 22522e346877SPeter Xu if (dirty) 22532e346877SPeter Xu swp_entry = make_migration_entry_dirty(swp_entry); 2254ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 2255804dd150SAndrea Arcangeli if (soft_dirty) 2256804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 2257f45ec5ffSPeter Xu if (uffd_wp) 2258f45ec5ffSPeter Xu entry = pte_swp_mkuffd_wp(entry); 2259ba988280SKirill A. Shutemov } else { 22606d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 22611462c52eSDavid Hildenbrand if (write) 2262161e393cSRick Edgecombe entry = pte_mkwrite(entry, vma); 22636c287605SDavid Hildenbrand if (anon_exclusive) 22646c287605SDavid Hildenbrand SetPageAnonExclusive(page + i); 2265eef1b3baSKirill A. Shutemov if (!young) 2266eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 2267e833bc50SPeter Xu /* NOTE: this may set soft-dirty too on some archs */ 2268e833bc50SPeter Xu if (dirty) 2269e833bc50SPeter Xu entry = pte_mkdirty(entry); 2270804dd150SAndrea Arcangeli if (soft_dirty) 2271804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 2272292924b2SPeter Xu if (uffd_wp) 2273292924b2SPeter Xu entry = pte_mkuffd_wp(entry); 22745ba72b4dSMiaohe Lin page_add_anon_rmap(page + i, vma, addr, RMAP_NONE); 2275ba988280SKirill A. Shutemov } 2276c33c7948SRyan Roberts VM_BUG_ON(!pte_none(ptep_get(pte))); 22772ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 2278c9c1ee20SHugh Dickins pte++; 2279eef1b3baSKirill A. Shutemov } 2280c9c1ee20SHugh Dickins pte_unmap(pte - 1); 2281eef1b3baSKirill A. Shutemov 2282cb67f428SHugh Dickins if (!pmd_migration) 2283cb67f428SHugh Dickins page_remove_rmap(page, vma, true); 228496d82debSHugh Dickins if (freeze) 228596d82debSHugh Dickins put_page(page); 2286eef1b3baSKirill A. Shutemov 2287eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2288eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2289eef1b3baSKirill A. Shutemov } 2290eef1b3baSKirill A. Shutemov 2291eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 2292af28a988SMatthew Wilcox (Oracle) unsigned long address, bool freeze, struct folio *folio) 2293eef1b3baSKirill A. Shutemov { 2294eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2295ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2296eef1b3baSKirill A. Shutemov 22977d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 22986f4f13e8SJérôme Glisse address & HPAGE_PMD_MASK, 2299ac46d4f3SJérôme Glisse (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); 2300ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2301ac46d4f3SJérôme Glisse ptl = pmd_lock(vma->vm_mm, pmd); 230233f4751eSNaoya Horiguchi 230333f4751eSNaoya Horiguchi /* 2304af28a988SMatthew Wilcox (Oracle) * If caller asks to setup a migration entry, we need a folio to check 2305af28a988SMatthew Wilcox (Oracle) * pmd against. Otherwise we can end up replacing wrong folio. 230633f4751eSNaoya Horiguchi */ 2307af28a988SMatthew Wilcox (Oracle) VM_BUG_ON(freeze && !folio); 230883a8441fSMatthew Wilcox (Oracle) VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); 230933f4751eSNaoya Horiguchi 23107f760917SDavid Hildenbrand if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || 231183a8441fSMatthew Wilcox (Oracle) is_pmd_migration_entry(*pmd)) { 2312cea33328SMiaohe Lin /* 2313cea33328SMiaohe Lin * It's safe to call pmd_page when folio is set because it's 2314cea33328SMiaohe Lin * guaranteed that pmd is present. 2315cea33328SMiaohe Lin */ 231683a8441fSMatthew Wilcox (Oracle) if (folio && folio != page_folio(pmd_page(*pmd))) 231783a8441fSMatthew Wilcox (Oracle) goto out; 2318ac46d4f3SJérôme Glisse __split_huge_pmd_locked(vma, pmd, range.start, freeze); 231983a8441fSMatthew Wilcox (Oracle) } 23207f760917SDavid Hildenbrand 2321e90309c9SKirill A. Shutemov out: 2322eef1b3baSKirill A. Shutemov spin_unlock(ptl); 2323ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 2324eef1b3baSKirill A. Shutemov } 2325eef1b3baSKirill A. Shutemov 2326fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2327af28a988SMatthew Wilcox (Oracle) bool freeze, struct folio *folio) 232894fcc585SAndrea Arcangeli { 232950722804SZach O'Keefe pmd_t *pmd = mm_find_pmd(vma->vm_mm, address); 233094fcc585SAndrea Arcangeli 233150722804SZach O'Keefe if (!pmd) 2332f72e7dcdSHugh Dickins return; 2333f72e7dcdSHugh Dickins 2334af28a988SMatthew Wilcox (Oracle) __split_huge_pmd(vma, pmd, address, freeze, folio); 233594fcc585SAndrea Arcangeli } 233694fcc585SAndrea Arcangeli 233771f9e58eSMiaohe Lin static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) 233871f9e58eSMiaohe Lin { 233971f9e58eSMiaohe Lin /* 234071f9e58eSMiaohe Lin * If the new address isn't hpage aligned and it could previously 234171f9e58eSMiaohe Lin * contain an hugepage: check if we need to split an huge pmd. 234271f9e58eSMiaohe Lin */ 234371f9e58eSMiaohe Lin if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && 234471f9e58eSMiaohe Lin range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), 234571f9e58eSMiaohe Lin ALIGN(address, HPAGE_PMD_SIZE))) 234671f9e58eSMiaohe Lin split_huge_pmd_address(vma, address, false, NULL); 234771f9e58eSMiaohe Lin } 234871f9e58eSMiaohe Lin 2349e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 235094fcc585SAndrea Arcangeli unsigned long start, 235194fcc585SAndrea Arcangeli unsigned long end, 235294fcc585SAndrea Arcangeli long adjust_next) 235394fcc585SAndrea Arcangeli { 235471f9e58eSMiaohe Lin /* Check if we need to split start first. */ 235571f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, start); 235671f9e58eSMiaohe Lin 235771f9e58eSMiaohe Lin /* Check if we need to split end next. */ 235871f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, end); 235994fcc585SAndrea Arcangeli 236094fcc585SAndrea Arcangeli /* 236168540502SMatthew Wilcox (Oracle) * If we're also updating the next vma vm_start, 236271f9e58eSMiaohe Lin * check if we need to split it. 236394fcc585SAndrea Arcangeli */ 236494fcc585SAndrea Arcangeli if (adjust_next > 0) { 236568540502SMatthew Wilcox (Oracle) struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end); 236694fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 2367f9d86a60SWei Yang nstart += adjust_next; 236871f9e58eSMiaohe Lin split_huge_pmd_if_needed(next, nstart); 236994fcc585SAndrea Arcangeli } 237094fcc585SAndrea Arcangeli } 2371e9b61f19SKirill A. Shutemov 2372684555aaSMatthew Wilcox (Oracle) static void unmap_folio(struct folio *folio) 2373e9b61f19SKirill A. Shutemov { 2374a98a2f0cSAlistair Popple enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | 2375a98a2f0cSAlistair Popple TTU_SYNC; 2376e9b61f19SKirill A. Shutemov 2377684555aaSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2378e9b61f19SKirill A. Shutemov 2379a98a2f0cSAlistair Popple /* 2380a98a2f0cSAlistair Popple * Anon pages need migration entries to preserve them, but file 2381a98a2f0cSAlistair Popple * pages can simply be left unmapped, then faulted back on demand. 2382a98a2f0cSAlistair Popple * If that is ever changed (perhaps for mlock), update remap_page(). 2383a98a2f0cSAlistair Popple */ 23844b8554c5SMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 23854b8554c5SMatthew Wilcox (Oracle) try_to_migrate(folio, ttu_flags); 2386a98a2f0cSAlistair Popple else 2387869f7ee6SMatthew Wilcox (Oracle) try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); 2388bd56086fSKirill A. Shutemov } 2389bd56086fSKirill A. Shutemov 23904eecb8b9SMatthew Wilcox (Oracle) static void remap_page(struct folio *folio, unsigned long nr) 2391e9b61f19SKirill A. Shutemov { 23924eecb8b9SMatthew Wilcox (Oracle) int i = 0; 2393ab02c252SHugh Dickins 2394684555aaSMatthew Wilcox (Oracle) /* If unmap_folio() uses try_to_migrate() on file, remove this check */ 23954eecb8b9SMatthew Wilcox (Oracle) if (!folio_test_anon(folio)) 2396ab02c252SHugh Dickins return; 23974eecb8b9SMatthew Wilcox (Oracle) for (;;) { 23984eecb8b9SMatthew Wilcox (Oracle) remove_migration_ptes(folio, folio, true); 23994eecb8b9SMatthew Wilcox (Oracle) i += folio_nr_pages(folio); 24004eecb8b9SMatthew Wilcox (Oracle) if (i >= nr) 24014eecb8b9SMatthew Wilcox (Oracle) break; 24024eecb8b9SMatthew Wilcox (Oracle) folio = folio_next(folio); 2403e9b61f19SKirill A. Shutemov } 2404ace71a19SKirill A. Shutemov } 2405e9b61f19SKirill A. Shutemov 240694866635SAlex Shi static void lru_add_page_tail(struct page *head, struct page *tail, 240788dcb9a3SAlex Shi struct lruvec *lruvec, struct list_head *list) 240888dcb9a3SAlex Shi { 240994866635SAlex Shi VM_BUG_ON_PAGE(!PageHead(head), head); 241094866635SAlex Shi VM_BUG_ON_PAGE(PageCompound(tail), head); 241194866635SAlex Shi VM_BUG_ON_PAGE(PageLRU(tail), head); 24126168d0daSAlex Shi lockdep_assert_held(&lruvec->lru_lock); 241388dcb9a3SAlex Shi 24146dbb5741SAlex Shi if (list) { 241588dcb9a3SAlex Shi /* page reclaim is reclaiming a huge page */ 24166dbb5741SAlex Shi VM_WARN_ON(PageLRU(head)); 241794866635SAlex Shi get_page(tail); 241894866635SAlex Shi list_add_tail(&tail->lru, list); 241988dcb9a3SAlex Shi } else { 24206dbb5741SAlex Shi /* head is still on lru (and we have it frozen) */ 24216dbb5741SAlex Shi VM_WARN_ON(!PageLRU(head)); 242207ca7606SHugh Dickins if (PageUnevictable(tail)) 242307ca7606SHugh Dickins tail->mlock_count = 0; 242407ca7606SHugh Dickins else 24256dbb5741SAlex Shi list_add_tail(&tail->lru, &head->lru); 242607ca7606SHugh Dickins SetPageLRU(tail); 242788dcb9a3SAlex Shi } 242888dcb9a3SAlex Shi } 242988dcb9a3SAlex Shi 243007e09c48SDavid Hildenbrand static void __split_huge_page_tail(struct folio *folio, int tail, 2431e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2432e9b61f19SKirill A. Shutemov { 243307e09c48SDavid Hildenbrand struct page *head = &folio->page; 2434e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 243507e09c48SDavid Hildenbrand /* 243607e09c48SDavid Hildenbrand * Careful: new_folio is not a "real" folio before we cleared PageTail. 243707e09c48SDavid Hildenbrand * Don't pass it around before clear_compound_head(). 243807e09c48SDavid Hildenbrand */ 243907e09c48SDavid Hildenbrand struct folio *new_folio = (struct folio *)page_tail; 2440e9b61f19SKirill A. Shutemov 24418df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2442e9b61f19SKirill A. Shutemov 2443e9b61f19SKirill A. Shutemov /* 2444605ca5edSKonstantin Khlebnikov * Clone page flags before unfreezing refcount. 2445605ca5edSKonstantin Khlebnikov * 2446605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow flags change, 24478958b249SHaitao Shi * for example lock_page() which set PG_waiters. 24486c287605SDavid Hildenbrand * 24496c287605SDavid Hildenbrand * Note that for mapped sub-pages of an anonymous THP, 2450684555aaSMatthew Wilcox (Oracle) * PG_anon_exclusive has been cleared in unmap_folio() and is stored in 24516c287605SDavid Hildenbrand * the migration entry instead from where remap_page() will restore it. 24526c287605SDavid Hildenbrand * We can still have PG_anon_exclusive set on effectively unmapped and 24536c287605SDavid Hildenbrand * unreferenced sub-pages of an anonymous THP: we can simply drop 24546c287605SDavid Hildenbrand * PG_anon_exclusive (-> PG_mappedtodisk) for these here. 2455e9b61f19SKirill A. Shutemov */ 2456e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2457e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2458e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2459e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 246038d8b4e6SHuang Ying (1L << PG_swapcache) | 2461e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2462e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2463e9b61f19SKirill A. Shutemov (1L << PG_active) | 24641899ad18SJohannes Weiner (1L << PG_workingset) | 2465e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2466b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 2467b0284cd2SCatalin Marinas #ifdef CONFIG_ARCH_USES_PG_ARCH_X 246872e6afa0SCatalin Marinas (1L << PG_arch_2) | 2469ef6458b1SPeter Collingbourne (1L << PG_arch_3) | 247072e6afa0SCatalin Marinas #endif 2471ec1c86b2SYu Zhao (1L << PG_dirty) | 2472ec1c86b2SYu Zhao LRU_GEN_MASK | LRU_REFS_MASK)); 2473e9b61f19SKirill A. Shutemov 2474cb67f428SHugh Dickins /* ->mapping in first and second tail page is replaced by other uses */ 2475173d9d9fSHugh Dickins VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2476173d9d9fSHugh Dickins page_tail); 2477173d9d9fSHugh Dickins page_tail->mapping = head->mapping; 2478173d9d9fSHugh Dickins page_tail->index = head->index + tail; 247971e2d666SMel Gorman 248071e2d666SMel Gorman /* 2481cfeed8ffSDavid Hildenbrand * page->private should not be set in tail pages. Fix up and warn once 2482cfeed8ffSDavid Hildenbrand * if private is unexpectedly set. 248371e2d666SMel Gorman */ 2484cfeed8ffSDavid Hildenbrand if (unlikely(page_tail->private)) { 2485cfeed8ffSDavid Hildenbrand VM_WARN_ON_ONCE_PAGE(true, page_tail); 2486b653db77SMatthew Wilcox (Oracle) page_tail->private = 0; 248771e2d666SMel Gorman } 248807e09c48SDavid Hildenbrand if (folio_test_swapcache(folio)) 248907e09c48SDavid Hildenbrand new_folio->swap.val = folio->swap.val + tail; 2490173d9d9fSHugh Dickins 2491605ca5edSKonstantin Khlebnikov /* Page flags must be visible before we make the page non-compound. */ 2492e9b61f19SKirill A. Shutemov smp_wmb(); 2493e9b61f19SKirill A. Shutemov 2494605ca5edSKonstantin Khlebnikov /* 2495605ca5edSKonstantin Khlebnikov * Clear PageTail before unfreezing page refcount. 2496605ca5edSKonstantin Khlebnikov * 2497605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow put_page() 2498605ca5edSKonstantin Khlebnikov * which needs correct compound_head(). 2499605ca5edSKonstantin Khlebnikov */ 2500e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2501e9b61f19SKirill A. Shutemov 2502605ca5edSKonstantin Khlebnikov /* Finally unfreeze refcount. Additional reference from page cache. */ 2503605ca5edSKonstantin Khlebnikov page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || 2504605ca5edSKonstantin Khlebnikov PageSwapCache(head))); 2505605ca5edSKonstantin Khlebnikov 2506e9b61f19SKirill A. Shutemov if (page_is_young(head)) 2507e9b61f19SKirill A. Shutemov set_page_young(page_tail); 2508e9b61f19SKirill A. Shutemov if (page_is_idle(head)) 2509e9b61f19SKirill A. Shutemov set_page_idle(page_tail); 2510e9b61f19SKirill A. Shutemov 2511e9b61f19SKirill A. Shutemov page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); 251294723aafSMichal Hocko 251394723aafSMichal Hocko /* 251494723aafSMichal Hocko * always add to the tail because some iterators expect new 251594723aafSMichal Hocko * pages to show after the currently processed elements - e.g. 251694723aafSMichal Hocko * migrate_pages 251794723aafSMichal Hocko */ 2518e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2519e9b61f19SKirill A. Shutemov } 2520e9b61f19SKirill A. Shutemov 2521baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2522b6769834SAlex Shi pgoff_t end) 2523e9b61f19SKirill A. Shutemov { 2524e809c3feSMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2525e809c3feSMatthew Wilcox (Oracle) struct page *head = &folio->page; 2526e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 25274101196bSMatthew Wilcox (Oracle) struct address_space *swap_cache = NULL; 25284101196bSMatthew Wilcox (Oracle) unsigned long offset = 0; 25298cce5475SKirill A. Shutemov unsigned int nr = thp_nr_pages(head); 2530509f0069SHugh Dickins int i, nr_dropped = 0; 2531e9b61f19SKirill A. Shutemov 2532e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2533be6c8982SZhou Guanghui split_page_memcg(head, nr); 2534e9b61f19SKirill A. Shutemov 253507e09c48SDavid Hildenbrand if (folio_test_anon(folio) && folio_test_swapcache(folio)) { 253607e09c48SDavid Hildenbrand offset = swp_offset(folio->swap); 253707e09c48SDavid Hildenbrand swap_cache = swap_address_space(folio->swap); 25384101196bSMatthew Wilcox (Oracle) xa_lock(&swap_cache->i_pages); 25394101196bSMatthew Wilcox (Oracle) } 25404101196bSMatthew Wilcox (Oracle) 2541f0953a1bSIngo Molnar /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ 2542e809c3feSMatthew Wilcox (Oracle) lruvec = folio_lruvec_lock(folio); 2543b6769834SAlex Shi 2544eac96c3eSYang Shi ClearPageHasHWPoisoned(head); 2545eac96c3eSYang Shi 25468cce5475SKirill A. Shutemov for (i = nr - 1; i >= 1; i--) { 254707e09c48SDavid Hildenbrand __split_huge_page_tail(folio, i, lruvec, list); 2548d144bf62SHugh Dickins /* Some pages can be beyond EOF: drop them from page cache */ 2549baa355fdSKirill A. Shutemov if (head[i].index >= end) { 2550fb5c2029SMatthew Wilcox (Oracle) struct folio *tail = page_folio(head + i); 2551fb5c2029SMatthew Wilcox (Oracle) 2552d144bf62SHugh Dickins if (shmem_mapping(head->mapping)) 2553509f0069SHugh Dickins nr_dropped++; 2554fb5c2029SMatthew Wilcox (Oracle) else if (folio_test_clear_dirty(tail)) 2555fb5c2029SMatthew Wilcox (Oracle) folio_account_cleaned(tail, 2556fb5c2029SMatthew Wilcox (Oracle) inode_to_wb(folio->mapping->host)); 2557fb5c2029SMatthew Wilcox (Oracle) __filemap_remove_folio(tail, NULL); 2558fb5c2029SMatthew Wilcox (Oracle) folio_put(tail); 25594101196bSMatthew Wilcox (Oracle) } else if (!PageAnon(page)) { 25604101196bSMatthew Wilcox (Oracle) __xa_store(&head->mapping->i_pages, head[i].index, 25614101196bSMatthew Wilcox (Oracle) head + i, 0); 25624101196bSMatthew Wilcox (Oracle) } else if (swap_cache) { 25634101196bSMatthew Wilcox (Oracle) __xa_store(&swap_cache->i_pages, offset + i, 25644101196bSMatthew Wilcox (Oracle) head + i, 0); 2565baa355fdSKirill A. Shutemov } 2566baa355fdSKirill A. Shutemov } 2567e9b61f19SKirill A. Shutemov 2568e9b61f19SKirill A. Shutemov ClearPageCompound(head); 25696168d0daSAlex Shi unlock_page_lruvec(lruvec); 2570b6769834SAlex Shi /* Caller disabled irqs, so they are still disabled here */ 2571f7da677bSVlastimil Babka 25728cce5475SKirill A. Shutemov split_page_owner(head, nr); 2573f7da677bSVlastimil Babka 2574baa355fdSKirill A. Shutemov /* See comment in __split_huge_page_tail() */ 2575baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2576aa5dc07fSMatthew Wilcox /* Additional pin to swap cache */ 25774101196bSMatthew Wilcox (Oracle) if (PageSwapCache(head)) { 257838d8b4e6SHuang Ying page_ref_add(head, 2); 25794101196bSMatthew Wilcox (Oracle) xa_unlock(&swap_cache->i_pages); 25804101196bSMatthew Wilcox (Oracle) } else { 2581baa355fdSKirill A. Shutemov page_ref_inc(head); 25824101196bSMatthew Wilcox (Oracle) } 2583baa355fdSKirill A. Shutemov } else { 2584aa5dc07fSMatthew Wilcox /* Additional pin to page cache */ 2585baa355fdSKirill A. Shutemov page_ref_add(head, 2); 2586b93b0163SMatthew Wilcox xa_unlock(&head->mapping->i_pages); 2587baa355fdSKirill A. Shutemov } 2588b6769834SAlex Shi local_irq_enable(); 2589e9b61f19SKirill A. Shutemov 2590509f0069SHugh Dickins if (nr_dropped) 2591509f0069SHugh Dickins shmem_uncharge(head->mapping->host, nr_dropped); 25924eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, nr); 2593e9b61f19SKirill A. Shutemov 259407e09c48SDavid Hildenbrand if (folio_test_swapcache(folio)) 259507e09c48SDavid Hildenbrand split_swap_cluster(folio->swap); 2596c4f9c701SHuang Ying 25978cce5475SKirill A. Shutemov for (i = 0; i < nr; i++) { 2598e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2599e9b61f19SKirill A. Shutemov if (subpage == page) 2600e9b61f19SKirill A. Shutemov continue; 2601e9b61f19SKirill A. Shutemov unlock_page(subpage); 2602e9b61f19SKirill A. Shutemov 2603e9b61f19SKirill A. Shutemov /* 2604e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2605e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2606e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2607e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2608e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2609e9b61f19SKirill A. Shutemov */ 26100b175468SMiaohe Lin free_page_and_swap_cache(subpage); 2611e9b61f19SKirill A. Shutemov } 2612e9b61f19SKirill A. Shutemov } 2613e9b61f19SKirill A. Shutemov 2614b8f593cdSHuang Ying /* Racy check whether the huge page can be split */ 2615d4b4084aSMatthew Wilcox (Oracle) bool can_split_folio(struct folio *folio, int *pextra_pins) 2616b8f593cdSHuang Ying { 2617b8f593cdSHuang Ying int extra_pins; 2618b8f593cdSHuang Ying 2619aa5dc07fSMatthew Wilcox /* Additional pins from page cache */ 2620d4b4084aSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 2621d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_test_swapcache(folio) ? 2622d4b4084aSMatthew Wilcox (Oracle) folio_nr_pages(folio) : 0; 2623b8f593cdSHuang Ying else 2624d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_nr_pages(folio); 2625b8f593cdSHuang Ying if (pextra_pins) 2626b8f593cdSHuang Ying *pextra_pins = extra_pins; 2627d4b4084aSMatthew Wilcox (Oracle) return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; 2628b8f593cdSHuang Ying } 2629b8f593cdSHuang Ying 26306d0a07edSAndrea Arcangeli /* 2631e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2632e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2633e9b61f19SKirill A. Shutemov * 2634e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2635e9b61f19SKirill A. Shutemov * The huge page must be locked. 2636e9b61f19SKirill A. Shutemov * 2637e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2638e9b61f19SKirill A. Shutemov * 2639e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2640e9b61f19SKirill A. Shutemov * the hugepage. 2641e9b61f19SKirill A. Shutemov * 2642e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2643e9b61f19SKirill A. Shutemov * they are not mapped. 2644e9b61f19SKirill A. Shutemov * 2645e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2646e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2647e9b61f19SKirill A. Shutemov * us. 2648e9b61f19SKirill A. Shutemov */ 2649e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2650e9b61f19SKirill A. Shutemov { 26514eecb8b9SMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2652f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *ds_queue = get_deferred_split_queue(folio); 26533e9a13daSMatthew Wilcox (Oracle) XA_STATE(xas, &folio->mapping->i_pages, folio->index); 2654baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2655baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2656504e070dSYang Shi int extra_pins, ret; 2657006d3ff2SHugh Dickins pgoff_t end; 2658478d134eSXu Yu bool is_hzp; 2659e9b61f19SKirill A. Shutemov 26603e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); 26613e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2662e9b61f19SKirill A. Shutemov 26633e9a13daSMatthew Wilcox (Oracle) is_hzp = is_huge_zero_page(&folio->page); 26644737edbbSNaoya Horiguchi if (is_hzp) { 26654737edbbSNaoya Horiguchi pr_warn_ratelimited("Called split_huge_page for huge zero page\n"); 2666478d134eSXu Yu return -EBUSY; 26674737edbbSNaoya Horiguchi } 2668478d134eSXu Yu 26693e9a13daSMatthew Wilcox (Oracle) if (folio_test_writeback(folio)) 267059807685SHuang Ying return -EBUSY; 267159807685SHuang Ying 26723e9a13daSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) { 2673e9b61f19SKirill A. Shutemov /* 2674c1e8d7c6SMichel Lespinasse * The caller does not necessarily hold an mmap_lock that would 2675baa355fdSKirill A. Shutemov * prevent the anon_vma disappearing so we first we take a 2676baa355fdSKirill A. Shutemov * reference to it and then lock the anon_vma for write. This 26772f031c6fSMatthew Wilcox (Oracle) * is similar to folio_lock_anon_vma_read except the write lock 2678baa355fdSKirill A. Shutemov * is taken to serialise against parallel split or collapse 2679baa355fdSKirill A. Shutemov * operations. 2680e9b61f19SKirill A. Shutemov */ 268129eea9b5SMatthew Wilcox (Oracle) anon_vma = folio_get_anon_vma(folio); 2682e9b61f19SKirill A. Shutemov if (!anon_vma) { 2683e9b61f19SKirill A. Shutemov ret = -EBUSY; 2684e9b61f19SKirill A. Shutemov goto out; 2685e9b61f19SKirill A. Shutemov } 2686006d3ff2SHugh Dickins end = -1; 2687baa355fdSKirill A. Shutemov mapping = NULL; 2688e9b61f19SKirill A. Shutemov anon_vma_lock_write(anon_vma); 2689baa355fdSKirill A. Shutemov } else { 26906a3edd29SYin Fengwei gfp_t gfp; 26916a3edd29SYin Fengwei 26923e9a13daSMatthew Wilcox (Oracle) mapping = folio->mapping; 2693baa355fdSKirill A. Shutemov 2694baa355fdSKirill A. Shutemov /* Truncated ? */ 2695baa355fdSKirill A. Shutemov if (!mapping) { 2696baa355fdSKirill A. Shutemov ret = -EBUSY; 2697baa355fdSKirill A. Shutemov goto out; 2698baa355fdSKirill A. Shutemov } 2699baa355fdSKirill A. Shutemov 27006a3edd29SYin Fengwei gfp = current_gfp_context(mapping_gfp_mask(mapping) & 27016a3edd29SYin Fengwei GFP_RECLAIM_MASK); 27026a3edd29SYin Fengwei 27030201ebf2SDavid Howells if (!filemap_release_folio(folio, gfp)) { 27046a3edd29SYin Fengwei ret = -EBUSY; 27056a3edd29SYin Fengwei goto out; 27066a3edd29SYin Fengwei } 27076a3edd29SYin Fengwei 27083e9a13daSMatthew Wilcox (Oracle) xas_split_alloc(&xas, folio, folio_order(folio), gfp); 27096b24ca4aSMatthew Wilcox (Oracle) if (xas_error(&xas)) { 27106b24ca4aSMatthew Wilcox (Oracle) ret = xas_error(&xas); 27116b24ca4aSMatthew Wilcox (Oracle) goto out; 27126b24ca4aSMatthew Wilcox (Oracle) } 27136b24ca4aSMatthew Wilcox (Oracle) 2714baa355fdSKirill A. Shutemov anon_vma = NULL; 2715baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 2716006d3ff2SHugh Dickins 2717006d3ff2SHugh Dickins /* 2718006d3ff2SHugh Dickins *__split_huge_page() may need to trim off pages beyond EOF: 2719006d3ff2SHugh Dickins * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, 2720006d3ff2SHugh Dickins * which cannot be nested inside the page tree lock. So note 2721006d3ff2SHugh Dickins * end now: i_size itself may be changed at any moment, but 27223e9a13daSMatthew Wilcox (Oracle) * folio lock is good enough to serialize the trimming. 2723006d3ff2SHugh Dickins */ 2724006d3ff2SHugh Dickins end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); 2725d144bf62SHugh Dickins if (shmem_mapping(mapping)) 2726d144bf62SHugh Dickins end = shmem_fallocend(mapping->host, end); 2727baa355fdSKirill A. Shutemov } 2728e9b61f19SKirill A. Shutemov 2729e9b61f19SKirill A. Shutemov /* 2730684555aaSMatthew Wilcox (Oracle) * Racy check if we can split the page, before unmap_folio() will 2731e9b61f19SKirill A. Shutemov * split PMDs 2732e9b61f19SKirill A. Shutemov */ 2733d4b4084aSMatthew Wilcox (Oracle) if (!can_split_folio(folio, &extra_pins)) { 2734fd4a7ac3SBaolin Wang ret = -EAGAIN; 2735e9b61f19SKirill A. Shutemov goto out_unlock; 2736e9b61f19SKirill A. Shutemov } 2737e9b61f19SKirill A. Shutemov 2738684555aaSMatthew Wilcox (Oracle) unmap_folio(folio); 2739e9b61f19SKirill A. Shutemov 2740b6769834SAlex Shi /* block interrupt reentry in xa_lock and spinlock */ 2741b6769834SAlex Shi local_irq_disable(); 2742baa355fdSKirill A. Shutemov if (mapping) { 2743baa355fdSKirill A. Shutemov /* 27443e9a13daSMatthew Wilcox (Oracle) * Check if the folio is present in page cache. 27453e9a13daSMatthew Wilcox (Oracle) * We assume all tail are present too, if folio is there. 2746baa355fdSKirill A. Shutemov */ 27476b24ca4aSMatthew Wilcox (Oracle) xas_lock(&xas); 27486b24ca4aSMatthew Wilcox (Oracle) xas_reset(&xas); 27493e9a13daSMatthew Wilcox (Oracle) if (xas_load(&xas) != folio) 2750baa355fdSKirill A. Shutemov goto fail; 2751baa355fdSKirill A. Shutemov } 2752baa355fdSKirill A. Shutemov 27530139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 2754364c1eebSYang Shi spin_lock(&ds_queue->split_queue_lock); 27553e9a13daSMatthew Wilcox (Oracle) if (folio_ref_freeze(folio, 1 + extra_pins)) { 27564375a553SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) { 2757364c1eebSYang Shi ds_queue->split_queue_len--; 27584375a553SMatthew Wilcox (Oracle) list_del(&folio->_deferred_list); 27599a982250SKirill A. Shutemov } 2760afb97172SWei Yang spin_unlock(&ds_queue->split_queue_lock); 276106d3eff6SKirill A. Shutemov if (mapping) { 27623e9a13daSMatthew Wilcox (Oracle) int nr = folio_nr_pages(folio); 2763bf9eceadSMuchun Song 27643e9a13daSMatthew Wilcox (Oracle) xas_split(&xas, folio, folio_order(folio)); 27653e9a13daSMatthew Wilcox (Oracle) if (folio_test_swapbacked(folio)) { 27663e9a13daSMatthew Wilcox (Oracle) __lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, 276757b2847dSMuchun Song -nr); 27681ca7554dSMarek Szyprowski } else { 27693e9a13daSMatthew Wilcox (Oracle) __lruvec_stat_mod_folio(folio, NR_FILE_THPS, 2770bf9eceadSMuchun Song -nr); 27711ca7554dSMarek Szyprowski filemap_nr_thps_dec(mapping); 27721ca7554dSMarek Szyprowski } 277306d3eff6SKirill A. Shutemov } 277406d3eff6SKirill A. Shutemov 2775b6769834SAlex Shi __split_huge_page(page, list, end); 2776e9b61f19SKirill A. Shutemov ret = 0; 2777baa355fdSKirill A. Shutemov } else { 2778364c1eebSYang Shi spin_unlock(&ds_queue->split_queue_lock); 2779504e070dSYang Shi fail: 2780504e070dSYang Shi if (mapping) 27816b24ca4aSMatthew Wilcox (Oracle) xas_unlock(&xas); 2782b6769834SAlex Shi local_irq_enable(); 27834eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, folio_nr_pages(folio)); 2784fd4a7ac3SBaolin Wang ret = -EAGAIN; 2785e9b61f19SKirill A. Shutemov } 2786e9b61f19SKirill A. Shutemov 2787e9b61f19SKirill A. Shutemov out_unlock: 2788baa355fdSKirill A. Shutemov if (anon_vma) { 2789e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 2790e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 2791baa355fdSKirill A. Shutemov } 2792baa355fdSKirill A. Shutemov if (mapping) 2793baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 2794e9b61f19SKirill A. Shutemov out: 279569a37a8bSMatthew Wilcox (Oracle) xas_destroy(&xas); 2796e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 2797e9b61f19SKirill A. Shutemov return ret; 2798e9b61f19SKirill A. Shutemov } 27999a982250SKirill A. Shutemov 28008dc4a8f1SMatthew Wilcox (Oracle) void folio_undo_large_rmappable(struct folio *folio) 28019a982250SKirill A. Shutemov { 28028dc4a8f1SMatthew Wilcox (Oracle) struct deferred_split *ds_queue; 28039a982250SKirill A. Shutemov unsigned long flags; 28049a982250SKirill A. Shutemov 2805deedad80SYin Fengwei /* 2806deedad80SYin Fengwei * At this point, there is no one trying to add the folio to 2807deedad80SYin Fengwei * deferred_list. If folio is not in deferred_list, it's safe 2808deedad80SYin Fengwei * to check without acquiring the split_queue_lock. 2809deedad80SYin Fengwei */ 28108dc4a8f1SMatthew Wilcox (Oracle) if (data_race(list_empty(&folio->_deferred_list))) 28118dc4a8f1SMatthew Wilcox (Oracle) return; 28128dc4a8f1SMatthew Wilcox (Oracle) 28138dc4a8f1SMatthew Wilcox (Oracle) ds_queue = get_deferred_split_queue(folio); 2814364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28158991de90SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) { 2816364c1eebSYang Shi ds_queue->split_queue_len--; 28178991de90SMatthew Wilcox (Oracle) list_del(&folio->_deferred_list); 28189a982250SKirill A. Shutemov } 2819364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 2820deedad80SYin Fengwei } 28219a982250SKirill A. Shutemov 2822f158ed61SMatthew Wilcox (Oracle) void deferred_split_folio(struct folio *folio) 28239a982250SKirill A. Shutemov { 2824f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *ds_queue = get_deferred_split_queue(folio); 282587eaceb3SYang Shi #ifdef CONFIG_MEMCG 28268991de90SMatthew Wilcox (Oracle) struct mem_cgroup *memcg = folio_memcg(folio); 282787eaceb3SYang Shi #endif 28289a982250SKirill A. Shutemov unsigned long flags; 28299a982250SKirill A. Shutemov 28308991de90SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); 28319a982250SKirill A. Shutemov 283287eaceb3SYang Shi /* 283387eaceb3SYang Shi * The try_to_unmap() in page reclaim path might reach here too, 283487eaceb3SYang Shi * this may cause a race condition to corrupt deferred split queue. 28358991de90SMatthew Wilcox (Oracle) * And, if page reclaim is already handling the same folio, it is 283687eaceb3SYang Shi * unnecessary to handle it again in shrinker. 283787eaceb3SYang Shi * 28388991de90SMatthew Wilcox (Oracle) * Check the swapcache flag to determine if the folio is being 28398991de90SMatthew Wilcox (Oracle) * handled by page reclaim since THP swap would add the folio into 284087eaceb3SYang Shi * swap cache before calling try_to_unmap(). 284187eaceb3SYang Shi */ 28428991de90SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 284387eaceb3SYang Shi return; 284487eaceb3SYang Shi 28458991de90SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) 28469a982250SKirill A. Shutemov return; 28479a982250SKirill A. Shutemov 2848364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28498991de90SMatthew Wilcox (Oracle) if (list_empty(&folio->_deferred_list)) { 2850f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 28518991de90SMatthew Wilcox (Oracle) list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); 2852364c1eebSYang Shi ds_queue->split_queue_len++; 285387eaceb3SYang Shi #ifdef CONFIG_MEMCG 285487eaceb3SYang Shi if (memcg) 28558991de90SMatthew Wilcox (Oracle) set_shrinker_bit(memcg, folio_nid(folio), 285654d91729SQi Zheng deferred_split_shrinker->id); 285787eaceb3SYang Shi #endif 28589a982250SKirill A. Shutemov } 2859364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28609a982250SKirill A. Shutemov } 28619a982250SKirill A. Shutemov 28629a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 28639a982250SKirill A. Shutemov struct shrink_control *sc) 28649a982250SKirill A. Shutemov { 2865a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2866364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 286787eaceb3SYang Shi 286887eaceb3SYang Shi #ifdef CONFIG_MEMCG 286987eaceb3SYang Shi if (sc->memcg) 287087eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 287187eaceb3SYang Shi #endif 2872364c1eebSYang Shi return READ_ONCE(ds_queue->split_queue_len); 28739a982250SKirill A. Shutemov } 28749a982250SKirill A. Shutemov 28759a982250SKirill A. Shutemov static unsigned long deferred_split_scan(struct shrinker *shrink, 28769a982250SKirill A. Shutemov struct shrink_control *sc) 28779a982250SKirill A. Shutemov { 2878a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2879364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 28809a982250SKirill A. Shutemov unsigned long flags; 28814375a553SMatthew Wilcox (Oracle) LIST_HEAD(list); 28824375a553SMatthew Wilcox (Oracle) struct folio *folio, *next; 28839a982250SKirill A. Shutemov int split = 0; 28849a982250SKirill A. Shutemov 288587eaceb3SYang Shi #ifdef CONFIG_MEMCG 288687eaceb3SYang Shi if (sc->memcg) 288787eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 288887eaceb3SYang Shi #endif 288987eaceb3SYang Shi 2890364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28919a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 28924375a553SMatthew Wilcox (Oracle) list_for_each_entry_safe(folio, next, &ds_queue->split_queue, 28934375a553SMatthew Wilcox (Oracle) _deferred_list) { 28944375a553SMatthew Wilcox (Oracle) if (folio_try_get(folio)) { 28954375a553SMatthew Wilcox (Oracle) list_move(&folio->_deferred_list, &list); 2896e3ae1953SKirill A. Shutemov } else { 28974375a553SMatthew Wilcox (Oracle) /* We lost race with folio_put() */ 28984375a553SMatthew Wilcox (Oracle) list_del_init(&folio->_deferred_list); 2899364c1eebSYang Shi ds_queue->split_queue_len--; 29009a982250SKirill A. Shutemov } 2901e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 2902e3ae1953SKirill A. Shutemov break; 29039a982250SKirill A. Shutemov } 2904364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 29059a982250SKirill A. Shutemov 29064375a553SMatthew Wilcox (Oracle) list_for_each_entry_safe(folio, next, &list, _deferred_list) { 29074375a553SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 2908fa41b900SKirill A. Shutemov goto next; 29099a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 29104375a553SMatthew Wilcox (Oracle) if (!split_folio(folio)) 29119a982250SKirill A. Shutemov split++; 29124375a553SMatthew Wilcox (Oracle) folio_unlock(folio); 2913fa41b900SKirill A. Shutemov next: 29144375a553SMatthew Wilcox (Oracle) folio_put(folio); 29159a982250SKirill A. Shutemov } 29169a982250SKirill A. Shutemov 2917364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 2918364c1eebSYang Shi list_splice_tail(&list, &ds_queue->split_queue); 2919364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 29209a982250SKirill A. Shutemov 2921cb8d68ecSKirill A. Shutemov /* 2922cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 2923cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 2924cb8d68ecSKirill A. Shutemov */ 2925364c1eebSYang Shi if (!split && list_empty(&ds_queue->split_queue)) 2926cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 2927cb8d68ecSKirill A. Shutemov return split; 29289a982250SKirill A. Shutemov } 29299a982250SKirill A. Shutemov 293049071d43SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 2931fa6c0231SZi Yan static void split_huge_pages_all(void) 293249071d43SKirill A. Shutemov { 293349071d43SKirill A. Shutemov struct zone *zone; 293449071d43SKirill A. Shutemov struct page *page; 2935630e7c5eSKefeng Wang struct folio *folio; 293649071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 293749071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 293849071d43SKirill A. Shutemov 2939fa6c0231SZi Yan pr_debug("Split all THPs\n"); 2940a17206daSMiaohe Lin for_each_zone(zone) { 2941a17206daSMiaohe Lin if (!managed_zone(zone)) 2942a17206daSMiaohe Lin continue; 294349071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 294449071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 2945a17206daSMiaohe Lin int nr_pages; 294649071d43SKirill A. Shutemov 29472b7aa91bSNaoya Horiguchi page = pfn_to_online_page(pfn); 2948630e7c5eSKefeng Wang if (!page || PageTail(page)) 2949630e7c5eSKefeng Wang continue; 2950630e7c5eSKefeng Wang folio = page_folio(page); 2951630e7c5eSKefeng Wang if (!folio_try_get(folio)) 295249071d43SKirill A. Shutemov continue; 295349071d43SKirill A. Shutemov 2954630e7c5eSKefeng Wang if (unlikely(page_folio(page) != folio)) 295549071d43SKirill A. Shutemov goto next; 295649071d43SKirill A. Shutemov 2957630e7c5eSKefeng Wang if (zone != folio_zone(folio)) 2958630e7c5eSKefeng Wang goto next; 2959630e7c5eSKefeng Wang 2960630e7c5eSKefeng Wang if (!folio_test_large(folio) 2961630e7c5eSKefeng Wang || folio_test_hugetlb(folio) 2962630e7c5eSKefeng Wang || !folio_test_lru(folio)) 296349071d43SKirill A. Shutemov goto next; 296449071d43SKirill A. Shutemov 296549071d43SKirill A. Shutemov total++; 2966630e7c5eSKefeng Wang folio_lock(folio); 2967630e7c5eSKefeng Wang nr_pages = folio_nr_pages(folio); 2968630e7c5eSKefeng Wang if (!split_folio(folio)) 296949071d43SKirill A. Shutemov split++; 2970a17206daSMiaohe Lin pfn += nr_pages - 1; 2971630e7c5eSKefeng Wang folio_unlock(folio); 297249071d43SKirill A. Shutemov next: 2973630e7c5eSKefeng Wang folio_put(folio); 2974fa6c0231SZi Yan cond_resched(); 297549071d43SKirill A. Shutemov } 297649071d43SKirill A. Shutemov } 297749071d43SKirill A. Shutemov 2978fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 297949071d43SKirill A. Shutemov } 2980fa6c0231SZi Yan 2981fa6c0231SZi Yan static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) 2982fa6c0231SZi Yan { 2983fa6c0231SZi Yan return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || 2984fa6c0231SZi Yan is_vm_hugetlb_page(vma); 2985fa6c0231SZi Yan } 2986fa6c0231SZi Yan 2987fa6c0231SZi Yan static int split_huge_pages_pid(int pid, unsigned long vaddr_start, 2988fa6c0231SZi Yan unsigned long vaddr_end) 2989fa6c0231SZi Yan { 2990fa6c0231SZi Yan int ret = 0; 2991fa6c0231SZi Yan struct task_struct *task; 2992fa6c0231SZi Yan struct mm_struct *mm; 2993fa6c0231SZi Yan unsigned long total = 0, split = 0; 2994fa6c0231SZi Yan unsigned long addr; 2995fa6c0231SZi Yan 2996fa6c0231SZi Yan vaddr_start &= PAGE_MASK; 2997fa6c0231SZi Yan vaddr_end &= PAGE_MASK; 2998fa6c0231SZi Yan 2999fa6c0231SZi Yan /* Find the task_struct from pid */ 3000fa6c0231SZi Yan rcu_read_lock(); 3001fa6c0231SZi Yan task = find_task_by_vpid(pid); 3002fa6c0231SZi Yan if (!task) { 3003fa6c0231SZi Yan rcu_read_unlock(); 3004fa6c0231SZi Yan ret = -ESRCH; 3005fa6c0231SZi Yan goto out; 3006fa6c0231SZi Yan } 3007fa6c0231SZi Yan get_task_struct(task); 3008fa6c0231SZi Yan rcu_read_unlock(); 3009fa6c0231SZi Yan 3010fa6c0231SZi Yan /* Find the mm_struct */ 3011fa6c0231SZi Yan mm = get_task_mm(task); 3012fa6c0231SZi Yan put_task_struct(task); 3013fa6c0231SZi Yan 3014fa6c0231SZi Yan if (!mm) { 3015fa6c0231SZi Yan ret = -EINVAL; 3016fa6c0231SZi Yan goto out; 3017fa6c0231SZi Yan } 3018fa6c0231SZi Yan 3019fa6c0231SZi Yan pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", 3020fa6c0231SZi Yan pid, vaddr_start, vaddr_end); 3021fa6c0231SZi Yan 3022fa6c0231SZi Yan mmap_read_lock(mm); 3023fa6c0231SZi Yan /* 3024fa6c0231SZi Yan * always increase addr by PAGE_SIZE, since we could have a PTE page 3025fa6c0231SZi Yan * table filled with PTE-mapped THPs, each of which is distinct. 3026fa6c0231SZi Yan */ 3027fa6c0231SZi Yan for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { 302874ba2b38SMiaohe Lin struct vm_area_struct *vma = vma_lookup(mm, addr); 3029fa6c0231SZi Yan struct page *page; 3030a644b0abSMatthew Wilcox (Oracle) struct folio *folio; 3031fa6c0231SZi Yan 303274ba2b38SMiaohe Lin if (!vma) 3033fa6c0231SZi Yan break; 3034fa6c0231SZi Yan 3035fa6c0231SZi Yan /* skip special VMA and hugetlb VMA */ 3036fa6c0231SZi Yan if (vma_not_suitable_for_thp_split(vma)) { 3037fa6c0231SZi Yan addr = vma->vm_end; 3038fa6c0231SZi Yan continue; 3039fa6c0231SZi Yan } 3040fa6c0231SZi Yan 3041fa6c0231SZi Yan /* FOLL_DUMP to ignore special (like zero) pages */ 304287d2762eSMiaohe Lin page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); 3043fa6c0231SZi Yan 3044f7091ed6SHaiyue Wang if (IS_ERR_OR_NULL(page)) 3045fa6c0231SZi Yan continue; 3046fa6c0231SZi Yan 3047a644b0abSMatthew Wilcox (Oracle) folio = page_folio(page); 3048a644b0abSMatthew Wilcox (Oracle) if (!is_transparent_hugepage(folio)) 3049fa6c0231SZi Yan goto next; 3050fa6c0231SZi Yan 3051fa6c0231SZi Yan total++; 3052a644b0abSMatthew Wilcox (Oracle) if (!can_split_folio(folio, NULL)) 3053fa6c0231SZi Yan goto next; 3054fa6c0231SZi Yan 3055a644b0abSMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 3056fa6c0231SZi Yan goto next; 3057fa6c0231SZi Yan 3058a644b0abSMatthew Wilcox (Oracle) if (!split_folio(folio)) 3059fa6c0231SZi Yan split++; 3060fa6c0231SZi Yan 3061a644b0abSMatthew Wilcox (Oracle) folio_unlock(folio); 3062fa6c0231SZi Yan next: 3063a644b0abSMatthew Wilcox (Oracle) folio_put(folio); 3064fa6c0231SZi Yan cond_resched(); 3065fa6c0231SZi Yan } 3066fa6c0231SZi Yan mmap_read_unlock(mm); 3067fa6c0231SZi Yan mmput(mm); 3068fa6c0231SZi Yan 3069fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 3070fa6c0231SZi Yan 3071fa6c0231SZi Yan out: 3072fa6c0231SZi Yan return ret; 3073fa6c0231SZi Yan } 3074fa6c0231SZi Yan 3075fbe37501SZi Yan static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, 3076fbe37501SZi Yan pgoff_t off_end) 3077fbe37501SZi Yan { 3078fbe37501SZi Yan struct filename *file; 3079fbe37501SZi Yan struct file *candidate; 3080fbe37501SZi Yan struct address_space *mapping; 3081fbe37501SZi Yan int ret = -EINVAL; 3082fbe37501SZi Yan pgoff_t index; 3083fbe37501SZi Yan int nr_pages = 1; 3084fbe37501SZi Yan unsigned long total = 0, split = 0; 3085fbe37501SZi Yan 3086fbe37501SZi Yan file = getname_kernel(file_path); 3087fbe37501SZi Yan if (IS_ERR(file)) 3088fbe37501SZi Yan return ret; 3089fbe37501SZi Yan 3090fbe37501SZi Yan candidate = file_open_name(file, O_RDONLY, 0); 3091fbe37501SZi Yan if (IS_ERR(candidate)) 3092fbe37501SZi Yan goto out; 3093fbe37501SZi Yan 3094fbe37501SZi Yan pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", 3095fbe37501SZi Yan file_path, off_start, off_end); 3096fbe37501SZi Yan 3097fbe37501SZi Yan mapping = candidate->f_mapping; 3098fbe37501SZi Yan 3099fbe37501SZi Yan for (index = off_start; index < off_end; index += nr_pages) { 31001fb130b2SChristoph Hellwig struct folio *folio = filemap_get_folio(mapping, index); 3101fbe37501SZi Yan 3102fbe37501SZi Yan nr_pages = 1; 310366dabbb6SChristoph Hellwig if (IS_ERR(folio)) 3104fbe37501SZi Yan continue; 3105fbe37501SZi Yan 31069ee2c086SMatthew Wilcox (Oracle) if (!folio_test_large(folio)) 3107fbe37501SZi Yan goto next; 3108fbe37501SZi Yan 3109fbe37501SZi Yan total++; 31109ee2c086SMatthew Wilcox (Oracle) nr_pages = folio_nr_pages(folio); 3111fbe37501SZi Yan 31129ee2c086SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 3113fbe37501SZi Yan goto next; 3114fbe37501SZi Yan 31159ee2c086SMatthew Wilcox (Oracle) if (!split_folio(folio)) 3116fbe37501SZi Yan split++; 3117fbe37501SZi Yan 31189ee2c086SMatthew Wilcox (Oracle) folio_unlock(folio); 3119fbe37501SZi Yan next: 31209ee2c086SMatthew Wilcox (Oracle) folio_put(folio); 3121fbe37501SZi Yan cond_resched(); 3122fbe37501SZi Yan } 3123fbe37501SZi Yan 3124fbe37501SZi Yan filp_close(candidate, NULL); 3125fbe37501SZi Yan ret = 0; 3126fbe37501SZi Yan 3127fbe37501SZi Yan pr_debug("%lu of %lu file-backed THP split\n", split, total); 3128fbe37501SZi Yan out: 3129fbe37501SZi Yan putname(file); 3130fbe37501SZi Yan return ret; 3131fbe37501SZi Yan } 3132fbe37501SZi Yan 3133fa6c0231SZi Yan #define MAX_INPUT_BUF_SZ 255 3134fa6c0231SZi Yan 3135fa6c0231SZi Yan static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, 3136fa6c0231SZi Yan size_t count, loff_t *ppops) 3137fa6c0231SZi Yan { 3138fa6c0231SZi Yan static DEFINE_MUTEX(split_debug_mutex); 3139fa6c0231SZi Yan ssize_t ret; 3140fbe37501SZi Yan /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ 3141fbe37501SZi Yan char input_buf[MAX_INPUT_BUF_SZ]; 3142fa6c0231SZi Yan int pid; 3143fa6c0231SZi Yan unsigned long vaddr_start, vaddr_end; 3144fa6c0231SZi Yan 3145fa6c0231SZi Yan ret = mutex_lock_interruptible(&split_debug_mutex); 3146fa6c0231SZi Yan if (ret) 3147fa6c0231SZi Yan return ret; 3148fa6c0231SZi Yan 3149fa6c0231SZi Yan ret = -EFAULT; 3150fa6c0231SZi Yan 3151fa6c0231SZi Yan memset(input_buf, 0, MAX_INPUT_BUF_SZ); 3152fa6c0231SZi Yan if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) 3153fa6c0231SZi Yan goto out; 3154fa6c0231SZi Yan 3155fa6c0231SZi Yan input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; 3156fbe37501SZi Yan 3157fbe37501SZi Yan if (input_buf[0] == '/') { 3158fbe37501SZi Yan char *tok; 3159fbe37501SZi Yan char *buf = input_buf; 3160fbe37501SZi Yan char file_path[MAX_INPUT_BUF_SZ]; 3161fbe37501SZi Yan pgoff_t off_start = 0, off_end = 0; 3162fbe37501SZi Yan size_t input_len = strlen(input_buf); 3163fbe37501SZi Yan 3164fbe37501SZi Yan tok = strsep(&buf, ","); 3165fbe37501SZi Yan if (tok) { 31661212e00cSMatthew Wilcox (Oracle) strcpy(file_path, tok); 3167fbe37501SZi Yan } else { 3168fbe37501SZi Yan ret = -EINVAL; 3169fbe37501SZi Yan goto out; 3170fbe37501SZi Yan } 3171fbe37501SZi Yan 3172fbe37501SZi Yan ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); 3173fbe37501SZi Yan if (ret != 2) { 3174fbe37501SZi Yan ret = -EINVAL; 3175fbe37501SZi Yan goto out; 3176fbe37501SZi Yan } 3177fbe37501SZi Yan ret = split_huge_pages_in_file(file_path, off_start, off_end); 3178fbe37501SZi Yan if (!ret) 3179fbe37501SZi Yan ret = input_len; 3180fbe37501SZi Yan 3181fbe37501SZi Yan goto out; 3182fbe37501SZi Yan } 3183fbe37501SZi Yan 3184fa6c0231SZi Yan ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); 3185fa6c0231SZi Yan if (ret == 1 && pid == 1) { 3186fa6c0231SZi Yan split_huge_pages_all(); 3187fa6c0231SZi Yan ret = strlen(input_buf); 3188fa6c0231SZi Yan goto out; 3189fa6c0231SZi Yan } else if (ret != 3) { 3190fa6c0231SZi Yan ret = -EINVAL; 3191fa6c0231SZi Yan goto out; 3192fa6c0231SZi Yan } 3193fa6c0231SZi Yan 3194fa6c0231SZi Yan ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); 3195fa6c0231SZi Yan if (!ret) 3196fa6c0231SZi Yan ret = strlen(input_buf); 3197fa6c0231SZi Yan out: 3198fa6c0231SZi Yan mutex_unlock(&split_debug_mutex); 3199fa6c0231SZi Yan return ret; 3200fa6c0231SZi Yan 3201fa6c0231SZi Yan } 3202fa6c0231SZi Yan 3203fa6c0231SZi Yan static const struct file_operations split_huge_pages_fops = { 3204fa6c0231SZi Yan .owner = THIS_MODULE, 3205fa6c0231SZi Yan .write = split_huge_pages_write, 3206fa6c0231SZi Yan .llseek = no_llseek, 3207fa6c0231SZi Yan }; 320849071d43SKirill A. Shutemov 320949071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 321049071d43SKirill A. Shutemov { 3211d9f7979cSGreg Kroah-Hartman debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 321249071d43SKirill A. Shutemov &split_huge_pages_fops); 321349071d43SKirill A. Shutemov return 0; 321449071d43SKirill A. Shutemov } 321549071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 321649071d43SKirill A. Shutemov #endif 3217616b8371SZi Yan 3218616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 32197f5abe60SDavid Hildenbrand int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 3220616b8371SZi Yan struct page *page) 3221616b8371SZi Yan { 3222616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3223616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3224616b8371SZi Yan unsigned long address = pvmw->address; 32256c287605SDavid Hildenbrand bool anon_exclusive; 3226616b8371SZi Yan pmd_t pmdval; 3227616b8371SZi Yan swp_entry_t entry; 3228ab6e3d09SNaoya Horiguchi pmd_t pmdswp; 3229616b8371SZi Yan 3230616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 32317f5abe60SDavid Hildenbrand return 0; 3232616b8371SZi Yan 3233616b8371SZi Yan flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); 32348a8683adSHuang Ying pmdval = pmdp_invalidate(vma, address, pvmw->pmd); 32356c287605SDavid Hildenbrand 3236088b8aa5SDavid Hildenbrand /* See page_try_share_anon_rmap(): invalidate PMD first. */ 32376c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 32386c287605SDavid Hildenbrand if (anon_exclusive && page_try_share_anon_rmap(page)) { 32396c287605SDavid Hildenbrand set_pmd_at(mm, address, pvmw->pmd, pmdval); 32407f5abe60SDavid Hildenbrand return -EBUSY; 32416c287605SDavid Hildenbrand } 32426c287605SDavid Hildenbrand 3243616b8371SZi Yan if (pmd_dirty(pmdval)) 3244616b8371SZi Yan set_page_dirty(page); 32454dd845b5SAlistair Popple if (pmd_write(pmdval)) 32464dd845b5SAlistair Popple entry = make_writable_migration_entry(page_to_pfn(page)); 32476c287605SDavid Hildenbrand else if (anon_exclusive) 32486c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); 32494dd845b5SAlistair Popple else 32504dd845b5SAlistair Popple entry = make_readable_migration_entry(page_to_pfn(page)); 32512e346877SPeter Xu if (pmd_young(pmdval)) 32522e346877SPeter Xu entry = make_migration_entry_young(entry); 32532e346877SPeter Xu if (pmd_dirty(pmdval)) 32542e346877SPeter Xu entry = make_migration_entry_dirty(entry); 3255ab6e3d09SNaoya Horiguchi pmdswp = swp_entry_to_pmd(entry); 3256ab6e3d09SNaoya Horiguchi if (pmd_soft_dirty(pmdval)) 3257ab6e3d09SNaoya Horiguchi pmdswp = pmd_swp_mksoft_dirty(pmdswp); 325824bf08c4SDavid Hildenbrand if (pmd_uffd_wp(pmdval)) 325924bf08c4SDavid Hildenbrand pmdswp = pmd_swp_mkuffd_wp(pmdswp); 3260ab6e3d09SNaoya Horiguchi set_pmd_at(mm, address, pvmw->pmd, pmdswp); 3261cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 3262616b8371SZi Yan put_page(page); 3263283fd6feSAnshuman Khandual trace_set_migration_pmd(address, pmd_val(pmdswp)); 32647f5abe60SDavid Hildenbrand 32657f5abe60SDavid Hildenbrand return 0; 3266616b8371SZi Yan } 3267616b8371SZi Yan 3268616b8371SZi Yan void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 3269616b8371SZi Yan { 3270616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3271616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3272616b8371SZi Yan unsigned long address = pvmw->address; 32734fba8f2aSMiaohe Lin unsigned long haddr = address & HPAGE_PMD_MASK; 3274616b8371SZi Yan pmd_t pmde; 3275616b8371SZi Yan swp_entry_t entry; 3276616b8371SZi Yan 3277616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 3278616b8371SZi Yan return; 3279616b8371SZi Yan 3280616b8371SZi Yan entry = pmd_to_swp_entry(*pvmw->pmd); 3281616b8371SZi Yan get_page(new); 32822e346877SPeter Xu pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); 3283ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pvmw->pmd)) 3284ab6e3d09SNaoya Horiguchi pmde = pmd_mksoft_dirty(pmde); 32853c811f78SDavid Hildenbrand if (is_writable_migration_entry(entry)) 3286161e393cSRick Edgecombe pmde = pmd_mkwrite(pmde, vma); 32878f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*pvmw->pmd)) 3288f1eb1bacSPeter Xu pmde = pmd_mkuffd_wp(pmde); 32892e346877SPeter Xu if (!is_migration_entry_young(entry)) 32902e346877SPeter Xu pmde = pmd_mkold(pmde); 32912e346877SPeter Xu /* NOTE: this may contain setting soft-dirty on some archs */ 32922e346877SPeter Xu if (PageDirty(new) && is_migration_entry_dirty(entry)) 32932e346877SPeter Xu pmde = pmd_mkdirty(pmde); 3294616b8371SZi Yan 32956c287605SDavid Hildenbrand if (PageAnon(new)) { 32966c287605SDavid Hildenbrand rmap_t rmap_flags = RMAP_COMPOUND; 32976c287605SDavid Hildenbrand 32986c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) 32996c287605SDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 33006c287605SDavid Hildenbrand 33014fba8f2aSMiaohe Lin page_add_anon_rmap(new, vma, haddr, rmap_flags); 33026c287605SDavid Hildenbrand } else { 3303cea86fe2SHugh Dickins page_add_file_rmap(new, vma, true); 33046c287605SDavid Hildenbrand } 33056c287605SDavid Hildenbrand VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); 33064fba8f2aSMiaohe Lin set_pmd_at(mm, haddr, pvmw->pmd, pmde); 33075cbcf225SMuchun Song 33085cbcf225SMuchun Song /* No need to invalidate - it was non-present before */ 3309616b8371SZi Yan update_mmu_cache_pmd(vma, address, pvmw->pmd); 3310283fd6feSAnshuman Khandual trace_remove_migration_pmd(address, pmd_val(pmde)); 3311616b8371SZi Yan } 3312616b8371SZi Yan #endif 3313