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 689a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker; 69f000565aSAndrea Arcangeli 7097ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 7156873f43SWang, Yalin struct page *huge_zero_page __read_mostly; 723b77e8c8SHugh Dickins unsigned long huge_zero_pfn __read_mostly = ~0UL; 734a6c1297SKirill A. Shutemov 74a7f4e6e4SZach O'Keefe bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, 75a7f4e6e4SZach O'Keefe bool smaps, bool in_pf, bool enforce_sysfs) 767635d9cbSMichal Hocko { 779fec5168SYang Shi if (!vma->vm_mm) /* vdso */ 78c0630669SYang Shi return false; 799fec5168SYang Shi 807da4e2cbSYang Shi /* 817da4e2cbSYang Shi * Explicitly disabled through madvise or prctl, or some 827da4e2cbSYang Shi * architectures may disable THP for some mappings, for 837da4e2cbSYang Shi * example, s390 kvm. 847da4e2cbSYang Shi * */ 857da4e2cbSYang Shi if ((vm_flags & VM_NOHUGEPAGE) || 867da4e2cbSYang Shi test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) 877da4e2cbSYang Shi return false; 887da4e2cbSYang Shi /* 897da4e2cbSYang Shi * If the hardware/firmware marked hugepage support disabled. 907da4e2cbSYang Shi */ 917da4e2cbSYang Shi if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX)) 929fec5168SYang Shi return false; 939fec5168SYang Shi 947da4e2cbSYang Shi /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ 957da4e2cbSYang Shi if (vma_is_dax(vma)) 967da4e2cbSYang Shi return in_pf; 977da4e2cbSYang Shi 987da4e2cbSYang Shi /* 997da4e2cbSYang Shi * Special VMA and hugetlb VMA. 1007da4e2cbSYang Shi * Must be checked after dax since some dax mappings may have 1017da4e2cbSYang Shi * VM_MIXEDMAP set. 1027da4e2cbSYang Shi */ 1039fec5168SYang Shi if (vm_flags & VM_NO_KHUGEPAGED) 1049fec5168SYang Shi return false; 1059fec5168SYang Shi 1067da4e2cbSYang Shi /* 1077da4e2cbSYang Shi * Check alignment for file vma and size for both file and anon vma. 1087da4e2cbSYang Shi * 1097da4e2cbSYang Shi * Skip the check for page fault. Huge fault does the check in fault 1107da4e2cbSYang Shi * handlers. And this check is not suitable for huge PUD fault. 1117da4e2cbSYang Shi */ 1127da4e2cbSYang Shi if (!in_pf && 1137da4e2cbSYang Shi !transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE))) 1149fec5168SYang Shi return false; 1159fec5168SYang Shi 1167da4e2cbSYang Shi /* 1177da4e2cbSYang Shi * Enabled via shmem mount options or sysfs settings. 1187da4e2cbSYang Shi * Must be done before hugepage flags check since shmem has its 1197da4e2cbSYang Shi * own flags. 1207da4e2cbSYang Shi */ 1217da4e2cbSYang Shi if (!in_pf && shmem_file(vma->vm_file)) 1227c6c6cc4SZach O'Keefe return shmem_huge_enabled(vma, !enforce_sysfs); 1239fec5168SYang Shi 124a7f4e6e4SZach O'Keefe /* Enforce sysfs THP requirements as necessary */ 125a7f4e6e4SZach O'Keefe if (enforce_sysfs && 126a7f4e6e4SZach O'Keefe (!hugepage_flags_enabled() || (!(vm_flags & VM_HUGEPAGE) && 127a7f4e6e4SZach O'Keefe !hugepage_flags_always()))) 1289fec5168SYang Shi return false; 1299fec5168SYang Shi 1309fec5168SYang Shi /* Only regular file is valid */ 1317da4e2cbSYang Shi if (!in_pf && file_thp_enabled(vma)) 13278d12c19SYang Shi return true; 1337635d9cbSMichal Hocko 1349fec5168SYang Shi if (!vma_is_anonymous(vma)) 1357635d9cbSMichal Hocko return false; 1369fec5168SYang Shi 1379fec5168SYang Shi if (vma_is_temporary_stack(vma)) 1389fec5168SYang Shi return false; 1399fec5168SYang Shi 1409fec5168SYang Shi /* 1419fec5168SYang Shi * THPeligible bit of smaps should show 1 for proper VMAs even 1429fec5168SYang Shi * though anon_vma is not initialized yet. 1437da4e2cbSYang Shi * 1447da4e2cbSYang Shi * Allow page fault since anon_vma may be not initialized until 1457da4e2cbSYang Shi * the first page fault. 1469fec5168SYang Shi */ 1479fec5168SYang Shi if (!vma->anon_vma) 1487da4e2cbSYang Shi return (smaps || in_pf); 1499fec5168SYang Shi 1509fec5168SYang Shi return true; 1517635d9cbSMichal Hocko } 1527635d9cbSMichal Hocko 153aaa9705bSMiaohe Lin static bool get_huge_zero_page(void) 15497ae1749SKirill A. Shutemov { 15597ae1749SKirill A. Shutemov struct page *zero_page; 15697ae1749SKirill A. Shutemov retry: 15797ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 158aaa9705bSMiaohe Lin return true; 15997ae1749SKirill A. Shutemov 16097ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 16197ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 162d8a8e1f0SKirill A. Shutemov if (!zero_page) { 163d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 164aaa9705bSMiaohe Lin return false; 165d8a8e1f0SKirill A. Shutemov } 16697ae1749SKirill A. Shutemov preempt_disable(); 1675918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 16897ae1749SKirill A. Shutemov preempt_enable(); 1695ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 17097ae1749SKirill A. Shutemov goto retry; 17197ae1749SKirill A. Shutemov } 1723b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); 17397ae1749SKirill A. Shutemov 17497ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 17597ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 17697ae1749SKirill A. Shutemov preempt_enable(); 177f4981502SLiu Shixin count_vm_event(THP_ZERO_PAGE_ALLOC); 178aaa9705bSMiaohe Lin return true; 17997ae1749SKirill A. Shutemov } 18097ae1749SKirill A. Shutemov 1816fcb52a5SAaron Lu static void put_huge_zero_page(void) 18297ae1749SKirill A. Shutemov { 18397ae1749SKirill A. Shutemov /* 18497ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 18597ae1749SKirill A. Shutemov * last reference. 18697ae1749SKirill A. Shutemov */ 18797ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 18897ae1749SKirill A. Shutemov } 18997ae1749SKirill A. Shutemov 1906fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 1916fcb52a5SAaron Lu { 1926fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1936fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1946fcb52a5SAaron Lu 1956fcb52a5SAaron Lu if (!get_huge_zero_page()) 1966fcb52a5SAaron Lu return NULL; 1976fcb52a5SAaron Lu 1986fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1996fcb52a5SAaron Lu put_huge_zero_page(); 2006fcb52a5SAaron Lu 2016fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 2026fcb52a5SAaron Lu } 2036fcb52a5SAaron Lu 2046fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 2056fcb52a5SAaron Lu { 2066fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2076fcb52a5SAaron Lu put_huge_zero_page(); 2086fcb52a5SAaron Lu } 2096fcb52a5SAaron Lu 21048896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 21197ae1749SKirill A. Shutemov struct shrink_control *sc) 21297ae1749SKirill A. Shutemov { 21397ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 21497ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 21548896466SGlauber Costa } 21697ae1749SKirill A. Shutemov 21748896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 21848896466SGlauber Costa struct shrink_control *sc) 21948896466SGlauber Costa { 22097ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2215918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2225918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2233b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, ~0UL); 2245ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 22548896466SGlauber Costa return HPAGE_PMD_NR; 22697ae1749SKirill A. Shutemov } 22797ae1749SKirill A. Shutemov 22897ae1749SKirill A. Shutemov return 0; 22997ae1749SKirill A. Shutemov } 23097ae1749SKirill A. Shutemov 23197ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 23248896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 23348896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 23497ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 23597ae1749SKirill A. Shutemov }; 23697ae1749SKirill A. Shutemov 23771e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 23871e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 23971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 24071e3aac0SAndrea Arcangeli { 241bfb0ffebSJoe Perches const char *output; 242bfb0ffebSJoe Perches 243444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 244bfb0ffebSJoe Perches output = "[always] madvise never"; 245bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 246bfb0ffebSJoe Perches &transparent_hugepage_flags)) 247bfb0ffebSJoe Perches output = "always [madvise] never"; 248444eb2a4SMel Gorman else 249bfb0ffebSJoe Perches output = "always madvise [never]"; 250bfb0ffebSJoe Perches 251bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 25271e3aac0SAndrea Arcangeli } 253444eb2a4SMel Gorman 25471e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 25571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 25671e3aac0SAndrea Arcangeli const char *buf, size_t count) 25771e3aac0SAndrea Arcangeli { 25821440d7eSDavid Rientjes ssize_t ret = count; 259ba76149fSAndrea Arcangeli 260f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 26121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 26221440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 263f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 26421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 26521440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 266f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 26721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 26821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 26921440d7eSDavid Rientjes } else 27021440d7eSDavid Rientjes ret = -EINVAL; 271ba76149fSAndrea Arcangeli 272ba76149fSAndrea Arcangeli if (ret > 0) { 273b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 274ba76149fSAndrea Arcangeli if (err) 275ba76149fSAndrea Arcangeli ret = err; 276ba76149fSAndrea Arcangeli } 277ba76149fSAndrea Arcangeli return ret; 27871e3aac0SAndrea Arcangeli } 27937139bb0SMiaohe Lin 28037139bb0SMiaohe Lin static struct kobj_attribute enabled_attr = __ATTR_RW(enabled); 28171e3aac0SAndrea Arcangeli 282b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 28371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 28471e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 28571e3aac0SAndrea Arcangeli { 286bfb0ffebSJoe Perches return sysfs_emit(buf, "%d\n", 287e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 28871e3aac0SAndrea Arcangeli } 289e27e6151SBen Hutchings 290b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 29171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 29271e3aac0SAndrea Arcangeli const char *buf, size_t count, 29371e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 29471e3aac0SAndrea Arcangeli { 295e27e6151SBen Hutchings unsigned long value; 296e27e6151SBen Hutchings int ret; 297e27e6151SBen Hutchings 298e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 299e27e6151SBen Hutchings if (ret < 0) 300e27e6151SBen Hutchings return ret; 301e27e6151SBen Hutchings if (value > 1) 30271e3aac0SAndrea Arcangeli return -EINVAL; 30371e3aac0SAndrea Arcangeli 304e27e6151SBen Hutchings if (value) 305e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 306e27e6151SBen Hutchings else 307e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 308e27e6151SBen Hutchings 30971e3aac0SAndrea Arcangeli return count; 31071e3aac0SAndrea Arcangeli } 31171e3aac0SAndrea Arcangeli 31271e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 31371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 31471e3aac0SAndrea Arcangeli { 315bfb0ffebSJoe Perches const char *output; 316bfb0ffebSJoe Perches 317bfb0ffebSJoe Perches if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, 318bfb0ffebSJoe Perches &transparent_hugepage_flags)) 319bfb0ffebSJoe Perches output = "[always] defer defer+madvise madvise never"; 320bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, 321bfb0ffebSJoe Perches &transparent_hugepage_flags)) 322bfb0ffebSJoe Perches output = "always [defer] defer+madvise madvise never"; 323bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, 324bfb0ffebSJoe Perches &transparent_hugepage_flags)) 325bfb0ffebSJoe Perches output = "always defer [defer+madvise] madvise never"; 326bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, 327bfb0ffebSJoe Perches &transparent_hugepage_flags)) 328bfb0ffebSJoe Perches output = "always defer defer+madvise [madvise] never"; 329bfb0ffebSJoe Perches else 330bfb0ffebSJoe Perches output = "always defer defer+madvise madvise [never]"; 331bfb0ffebSJoe Perches 332bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 33371e3aac0SAndrea Arcangeli } 33421440d7eSDavid Rientjes 33571e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 33671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 33771e3aac0SAndrea Arcangeli const char *buf, size_t count) 33871e3aac0SAndrea Arcangeli { 339f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 34021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 34121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 34221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 34321440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 344f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer+madvise")) { 34521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 34621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 34721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 34821440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 349f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer")) { 3504fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 3514fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 3524fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 3534fad7fb6SDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 354f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 35521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 35621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 35721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 35821440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 359f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 36021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 36121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 36221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 36321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 36421440d7eSDavid Rientjes } else 36521440d7eSDavid Rientjes return -EINVAL; 36621440d7eSDavid Rientjes 36721440d7eSDavid Rientjes return count; 36871e3aac0SAndrea Arcangeli } 36937139bb0SMiaohe Lin static struct kobj_attribute defrag_attr = __ATTR_RW(defrag); 37071e3aac0SAndrea Arcangeli 37179da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 37279da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 37379da5407SKirill A. Shutemov { 374b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 37579da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 37679da5407SKirill A. Shutemov } 37779da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 37879da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 37979da5407SKirill A. Shutemov { 380b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 38179da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 38279da5407SKirill A. Shutemov } 38337139bb0SMiaohe Lin static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page); 38449920d28SHugh Dickins 38549920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 38649920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 38749920d28SHugh Dickins { 388ae7a927dSJoe Perches return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); 38949920d28SHugh Dickins } 39049920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 39149920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 39249920d28SHugh Dickins 39371e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 39471e3aac0SAndrea Arcangeli &enabled_attr.attr, 39571e3aac0SAndrea Arcangeli &defrag_attr.attr, 39679da5407SKirill A. Shutemov &use_zero_page_attr.attr, 39749920d28SHugh Dickins &hpage_pmd_size_attr.attr, 398396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_SHMEM 3995a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 4005a6e75f8SKirill A. Shutemov #endif 40171e3aac0SAndrea Arcangeli NULL, 40271e3aac0SAndrea Arcangeli }; 40371e3aac0SAndrea Arcangeli 4048aa95a21SArvind Yadav static const struct attribute_group hugepage_attr_group = { 40571e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 406ba76149fSAndrea Arcangeli }; 407ba76149fSAndrea Arcangeli 408569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 409569e5590SShaohua Li { 410569e5590SShaohua Li int err; 411569e5590SShaohua Li 412569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 413569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 414ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 415569e5590SShaohua Li return -ENOMEM; 416569e5590SShaohua Li } 417569e5590SShaohua Li 418569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 419569e5590SShaohua Li if (err) { 420ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 421569e5590SShaohua Li goto delete_obj; 422569e5590SShaohua Li } 423569e5590SShaohua Li 424569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 425569e5590SShaohua Li if (err) { 426ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 427569e5590SShaohua Li goto remove_hp_group; 428569e5590SShaohua Li } 429569e5590SShaohua Li 430569e5590SShaohua Li return 0; 431569e5590SShaohua Li 432569e5590SShaohua Li remove_hp_group: 433569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 434569e5590SShaohua Li delete_obj: 435569e5590SShaohua Li kobject_put(*hugepage_kobj); 436569e5590SShaohua Li return err; 437569e5590SShaohua Li } 438569e5590SShaohua Li 439569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 440569e5590SShaohua Li { 441569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 442569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 443569e5590SShaohua Li kobject_put(hugepage_kobj); 444569e5590SShaohua Li } 445569e5590SShaohua Li #else 446569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 447569e5590SShaohua Li { 448569e5590SShaohua Li return 0; 449569e5590SShaohua Li } 450569e5590SShaohua Li 451569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 452569e5590SShaohua Li { 453569e5590SShaohua Li } 45471e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 45571e3aac0SAndrea Arcangeli 45671e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 45771e3aac0SAndrea Arcangeli { 45871e3aac0SAndrea Arcangeli int err; 459569e5590SShaohua Li struct kobject *hugepage_kobj; 46071e3aac0SAndrea Arcangeli 4614b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 462bae84953SAneesh Kumar K.V /* 463bae84953SAneesh Kumar K.V * Hardware doesn't support hugepages, hence disable 464bae84953SAneesh Kumar K.V * DAX PMD support. 465bae84953SAneesh Kumar K.V */ 466bae84953SAneesh Kumar K.V transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX; 467569e5590SShaohua Li return -EINVAL; 4684b7167b9SAndrea Arcangeli } 4694b7167b9SAndrea Arcangeli 470ff20c2e0SKirill A. Shutemov /* 471ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 472ff20c2e0SKirill A. Shutemov */ 473ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); 474ff20c2e0SKirill A. Shutemov /* 475ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 476ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 477ff20c2e0SKirill A. Shutemov */ 478ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 479ff20c2e0SKirill A. Shutemov 480569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 481569e5590SShaohua Li if (err) 48265ebb64fSKirill A. Shutemov goto err_sysfs; 483ba76149fSAndrea Arcangeli 484b46e756fSKirill A. Shutemov err = khugepaged_init(); 485ba76149fSAndrea Arcangeli if (err) 48665ebb64fSKirill A. Shutemov goto err_slab; 487ba76149fSAndrea Arcangeli 488e33c267aSRoman Gushchin err = register_shrinker(&huge_zero_page_shrinker, "thp-zero"); 48965ebb64fSKirill A. Shutemov if (err) 49065ebb64fSKirill A. Shutemov goto err_hzp_shrinker; 491e33c267aSRoman Gushchin err = register_shrinker(&deferred_split_shrinker, "thp-deferred_split"); 4929a982250SKirill A. Shutemov if (err) 4939a982250SKirill A. Shutemov goto err_split_shrinker; 49497ae1749SKirill A. Shutemov 49597562cd2SRik van Riel /* 49697562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 49797562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 49897562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 49997562cd2SRik van Riel */ 500ca79b0c2SArun KS if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { 50197562cd2SRik van Riel transparent_hugepage_flags = 0; 50279553da2SKirill A. Shutemov return 0; 50379553da2SKirill A. Shutemov } 50497562cd2SRik van Riel 50579553da2SKirill A. Shutemov err = start_stop_khugepaged(); 50665ebb64fSKirill A. Shutemov if (err) 50765ebb64fSKirill A. Shutemov goto err_khugepaged; 508ba76149fSAndrea Arcangeli 509569e5590SShaohua Li return 0; 51065ebb64fSKirill A. Shutemov err_khugepaged: 5119a982250SKirill A. Shutemov unregister_shrinker(&deferred_split_shrinker); 5129a982250SKirill A. Shutemov err_split_shrinker: 51365ebb64fSKirill A. Shutemov unregister_shrinker(&huge_zero_page_shrinker); 51465ebb64fSKirill A. Shutemov err_hzp_shrinker: 515b46e756fSKirill A. Shutemov khugepaged_destroy(); 51665ebb64fSKirill A. Shutemov err_slab: 517569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 51865ebb64fSKirill A. Shutemov err_sysfs: 519ba76149fSAndrea Arcangeli return err; 52071e3aac0SAndrea Arcangeli } 521a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 52271e3aac0SAndrea Arcangeli 52371e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 52471e3aac0SAndrea Arcangeli { 52571e3aac0SAndrea Arcangeli int ret = 0; 52671e3aac0SAndrea Arcangeli if (!str) 52771e3aac0SAndrea Arcangeli goto out; 52871e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 52971e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 53071e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53171e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 53271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53371e3aac0SAndrea Arcangeli ret = 1; 53471e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 53571e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 53671e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53771e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 53871e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53971e3aac0SAndrea Arcangeli ret = 1; 54071e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 54171e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 54271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 54371e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 54471e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 54571e3aac0SAndrea Arcangeli ret = 1; 54671e3aac0SAndrea Arcangeli } 54771e3aac0SAndrea Arcangeli out: 54871e3aac0SAndrea Arcangeli if (!ret) 549ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 55071e3aac0SAndrea Arcangeli return ret; 55171e3aac0SAndrea Arcangeli } 55271e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 55371e3aac0SAndrea Arcangeli 554f55e1014SLinus Torvalds pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 55571e3aac0SAndrea Arcangeli { 556f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 55771e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 55871e3aac0SAndrea Arcangeli return pmd; 55971e3aac0SAndrea Arcangeli } 56071e3aac0SAndrea Arcangeli 56187eaceb3SYang Shi #ifdef CONFIG_MEMCG 56287eaceb3SYang Shi static inline struct deferred_split *get_deferred_split_queue(struct page *page) 5639a982250SKirill A. Shutemov { 564bcfe06bfSRoman Gushchin struct mem_cgroup *memcg = page_memcg(compound_head(page)); 56587eaceb3SYang Shi struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); 56687eaceb3SYang Shi 56787eaceb3SYang Shi if (memcg) 56887eaceb3SYang Shi return &memcg->deferred_split_queue; 56987eaceb3SYang Shi else 57087eaceb3SYang Shi return &pgdat->deferred_split_queue; 5719a982250SKirill A. Shutemov } 57287eaceb3SYang Shi #else 57387eaceb3SYang Shi static inline struct deferred_split *get_deferred_split_queue(struct page *page) 57487eaceb3SYang Shi { 57587eaceb3SYang Shi struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); 57687eaceb3SYang Shi 57787eaceb3SYang Shi return &pgdat->deferred_split_queue; 57887eaceb3SYang Shi } 57987eaceb3SYang Shi #endif 5809a982250SKirill A. Shutemov 5819a982250SKirill A. Shutemov void prep_transhuge_page(struct page *page) 5829a982250SKirill A. Shutemov { 5839a982250SKirill A. Shutemov /* 584d764afedSMiaohe Lin * we use page->mapping and page->index in second tail page 5859a982250SKirill A. Shutemov * as list_head: assuming THP order >= 2 5869a982250SKirill A. Shutemov */ 5879a982250SKirill A. Shutemov 5889a982250SKirill A. Shutemov INIT_LIST_HEAD(page_deferred_list(page)); 5899a982250SKirill A. Shutemov set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); 5909a982250SKirill A. Shutemov } 5919a982250SKirill A. Shutemov 592562beb72SMiaohe Lin static inline bool is_transparent_hugepage(struct page *page) 593005ba37cSSean Christopherson { 594005ba37cSSean Christopherson if (!PageCompound(page)) 595fa1f68ccSZou Wei return false; 596005ba37cSSean Christopherson 597005ba37cSSean Christopherson page = compound_head(page); 598005ba37cSSean Christopherson return is_huge_zero_page(page) || 599005ba37cSSean Christopherson page[1].compound_dtor == TRANSHUGE_PAGE_DTOR; 600005ba37cSSean Christopherson } 601005ba37cSSean Christopherson 60297d3d0f9SKirill A. Shutemov static unsigned long __thp_get_unmapped_area(struct file *filp, 60397d3d0f9SKirill A. Shutemov unsigned long addr, unsigned long len, 60474d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 60574d2fad1SToshi Kani { 60674d2fad1SToshi Kani loff_t off_end = off + len; 60774d2fad1SToshi Kani loff_t off_align = round_up(off, size); 60897d3d0f9SKirill A. Shutemov unsigned long len_pad, ret; 60974d2fad1SToshi Kani 61074d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 61174d2fad1SToshi Kani return 0; 61274d2fad1SToshi Kani 61374d2fad1SToshi Kani len_pad = len + size; 61474d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 61574d2fad1SToshi Kani return 0; 61674d2fad1SToshi Kani 61797d3d0f9SKirill A. Shutemov ret = current->mm->get_unmapped_area(filp, addr, len_pad, 61874d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 61997d3d0f9SKirill A. Shutemov 62097d3d0f9SKirill A. Shutemov /* 62197d3d0f9SKirill A. Shutemov * The failure might be due to length padding. The caller will retry 62297d3d0f9SKirill A. Shutemov * without the padding. 62397d3d0f9SKirill A. Shutemov */ 62497d3d0f9SKirill A. Shutemov if (IS_ERR_VALUE(ret)) 62574d2fad1SToshi Kani return 0; 62674d2fad1SToshi Kani 62797d3d0f9SKirill A. Shutemov /* 62897d3d0f9SKirill A. Shutemov * Do not try to align to THP boundary if allocation at the address 62997d3d0f9SKirill A. Shutemov * hint succeeds. 63097d3d0f9SKirill A. Shutemov */ 63197d3d0f9SKirill A. Shutemov if (ret == addr) 63274d2fad1SToshi Kani return addr; 63397d3d0f9SKirill A. Shutemov 63497d3d0f9SKirill A. Shutemov ret += (off - ret) & (size - 1); 63597d3d0f9SKirill A. Shutemov return ret; 63674d2fad1SToshi Kani } 63774d2fad1SToshi Kani 63874d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 63974d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 64074d2fad1SToshi Kani { 64197d3d0f9SKirill A. Shutemov unsigned long ret; 64274d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 64374d2fad1SToshi Kani 64497d3d0f9SKirill A. Shutemov ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); 64597d3d0f9SKirill A. Shutemov if (ret) 64697d3d0f9SKirill A. Shutemov return ret; 6471854bc6eSWilliam Kucharski 64874d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 64974d2fad1SToshi Kani } 65074d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 65174d2fad1SToshi Kani 6522b740303SSouptick Joarder static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, 6532b740303SSouptick Joarder struct page *page, gfp_t gfp) 65471e3aac0SAndrea Arcangeli { 65582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 65671e3aac0SAndrea Arcangeli pgtable_t pgtable; 65782b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 6582b740303SSouptick Joarder vm_fault_t ret = 0; 65971e3aac0SAndrea Arcangeli 660309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 66100501b53SJohannes Weiner 6628f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(page), vma->vm_mm, gfp)) { 6636b251fc9SAndrea Arcangeli put_page(page); 6646b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 66585b9f46eSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK_CHARGE); 6666b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 6676b251fc9SAndrea Arcangeli } 6689d82c694SJohannes Weiner cgroup_throttle_swaprate(page, gfp); 66971e3aac0SAndrea Arcangeli 6704cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 67100501b53SJohannes Weiner if (unlikely(!pgtable)) { 6726b31d595SMichal Hocko ret = VM_FAULT_OOM; 6736b31d595SMichal Hocko goto release; 67400501b53SJohannes Weiner } 67500501b53SJohannes Weiner 676c79b57e4SHuang Ying clear_huge_page(page, vmf->address, HPAGE_PMD_NR); 67752f37629SMinchan Kim /* 67852f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 67952f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 68052f37629SMinchan Kim * write. 68152f37629SMinchan Kim */ 68271e3aac0SAndrea Arcangeli __SetPageUptodate(page); 68371e3aac0SAndrea Arcangeli 68482b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 68582b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 6866b31d595SMichal Hocko goto unlock_release; 68771e3aac0SAndrea Arcangeli } else { 68871e3aac0SAndrea Arcangeli pmd_t entry; 6896b251fc9SAndrea Arcangeli 6906b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 6916b31d595SMichal Hocko if (ret) 6926b31d595SMichal Hocko goto unlock_release; 6936b31d595SMichal Hocko 6946b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 6956b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 69682b0f8c3SJan Kara spin_unlock(vmf->ptl); 6976b251fc9SAndrea Arcangeli put_page(page); 698bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 6998fd5eda4SMiaohe Lin ret = handle_userfault(vmf, VM_UFFD_MISSING); 7008fd5eda4SMiaohe Lin VM_BUG_ON(ret & VM_FAULT_FALLBACK); 7018fd5eda4SMiaohe Lin return ret; 7026b251fc9SAndrea Arcangeli } 7036b251fc9SAndrea Arcangeli 7043122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 705f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 70640f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, haddr); 707b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 70882b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 70982b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 710fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 711bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 712c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 71382b0f8c3SJan Kara spin_unlock(vmf->ptl); 7146b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 7159d82c694SJohannes Weiner count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); 71671e3aac0SAndrea Arcangeli } 71771e3aac0SAndrea Arcangeli 718aa2e878eSDavid Rientjes return 0; 7196b31d595SMichal Hocko unlock_release: 7206b31d595SMichal Hocko spin_unlock(vmf->ptl); 7216b31d595SMichal Hocko release: 7226b31d595SMichal Hocko if (pgtable) 7236b31d595SMichal Hocko pte_free(vma->vm_mm, pgtable); 7246b31d595SMichal Hocko put_page(page); 7256b31d595SMichal Hocko return ret; 7266b31d595SMichal Hocko 72771e3aac0SAndrea Arcangeli } 72871e3aac0SAndrea Arcangeli 729444eb2a4SMel Gorman /* 73021440d7eSDavid Rientjes * always: directly stall for all thp allocations 73121440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 73221440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 73321440d7eSDavid Rientjes * fail if not immediately available 73421440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 73521440d7eSDavid Rientjes * available 73621440d7eSDavid Rientjes * never: never stall for any thp allocation 737444eb2a4SMel Gorman */ 738164cc4feSRik van Riel gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) 7390bbbc0b3SAndrea Arcangeli { 740164cc4feSRik van Riel const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); 74189c83fb5SMichal Hocko 742ac79f78dSDavid Rientjes /* Always do synchronous compaction */ 74321440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 744a8282608SAndrea Arcangeli return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 745ac79f78dSDavid Rientjes 746ac79f78dSDavid Rientjes /* Kick kcompactd and fail quickly */ 74721440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 74819deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 749ac79f78dSDavid Rientjes 750ac79f78dSDavid Rientjes /* Synchronous compaction if madvised, otherwise kick kcompactd */ 75121440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 75219deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 75319deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 754ac79f78dSDavid Rientjes __GFP_KSWAPD_RECLAIM); 755ac79f78dSDavid Rientjes 756ac79f78dSDavid Rientjes /* Only do synchronous compaction if madvised */ 75721440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 75819deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 75919deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); 760ac79f78dSDavid Rientjes 76119deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT; 762444eb2a4SMel Gorman } 763444eb2a4SMel Gorman 764c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 7652efeb8daSMiaohe Lin static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 76697ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 7675918d10aSKirill A. Shutemov struct page *zero_page) 768fc9fe822SKirill A. Shutemov { 769fc9fe822SKirill A. Shutemov pmd_t entry; 7707c414164SAndrew Morton if (!pmd_none(*pmd)) 7712efeb8daSMiaohe Lin return; 7725918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 773fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 7746b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 775fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 776c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 777fc9fe822SKirill A. Shutemov } 778fc9fe822SKirill A. Shutemov 7792b740303SSouptick Joarder vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) 78071e3aac0SAndrea Arcangeli { 78182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 782077fcf11SAneesh Kumar K.V gfp_t gfp; 783cb196ee1SMatthew Wilcox (Oracle) struct folio *folio; 78482b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 78571e3aac0SAndrea Arcangeli 78643675e6fSYang Shi if (!transhuge_vma_suitable(vma, haddr)) 787c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 78871e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 78971e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 7904fa6893fSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 791d2081b2bSYang Shi 79282b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 793bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 79479da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 79580371957SKirill A. Shutemov pgtable_t pgtable; 7965918d10aSKirill A. Shutemov struct page *zero_page; 7972b740303SSouptick Joarder vm_fault_t ret; 7984cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 79980371957SKirill A. Shutemov if (unlikely(!pgtable)) 80080371957SKirill A. Shutemov return VM_FAULT_OOM; 8016fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 8025918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 803bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 80497ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 805c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 80697ae1749SKirill A. Shutemov } 80782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 8086b251fc9SAndrea Arcangeli ret = 0; 80982b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 8106b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 8116b31d595SMichal Hocko if (ret) { 8126b31d595SMichal Hocko spin_unlock(vmf->ptl); 813bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 8146b31d595SMichal Hocko } else if (userfaultfd_missing(vma)) { 81582b0f8c3SJan Kara spin_unlock(vmf->ptl); 816bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 81782b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 8186b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 8196b251fc9SAndrea Arcangeli } else { 820bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 82182b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 822fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 82382b0f8c3SJan Kara spin_unlock(vmf->ptl); 8246b251fc9SAndrea Arcangeli } 825bfe8cc1dSGerald Schaefer } else { 82682b0f8c3SJan Kara spin_unlock(vmf->ptl); 827bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 828bfe8cc1dSGerald Schaefer } 8296b251fc9SAndrea Arcangeli return ret; 83080371957SKirill A. Shutemov } 831164cc4feSRik van Riel gfp = vma_thp_gfp_mask(vma); 832cb196ee1SMatthew Wilcox (Oracle) folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); 833cb196ee1SMatthew Wilcox (Oracle) if (unlikely(!folio)) { 83481ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 835c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 83681ab4201SAndi Kleen } 837cb196ee1SMatthew Wilcox (Oracle) return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); 83871e3aac0SAndrea Arcangeli } 83971e3aac0SAndrea Arcangeli 840ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 8413b6521f5SOliver O'Halloran pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, 8423b6521f5SOliver O'Halloran pgtable_t pgtable) 8435cad465dSMatthew Wilcox { 8445cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 8455cad465dSMatthew Wilcox pmd_t entry; 8465cad465dSMatthew Wilcox spinlock_t *ptl; 8475cad465dSMatthew Wilcox 8485cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 849c6f3c5eeSAneesh Kumar K.V if (!pmd_none(*pmd)) { 850c6f3c5eeSAneesh Kumar K.V if (write) { 851c6f3c5eeSAneesh Kumar K.V if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { 852c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); 853c6f3c5eeSAneesh Kumar K.V goto out_unlock; 854c6f3c5eeSAneesh Kumar K.V } 855c6f3c5eeSAneesh Kumar K.V entry = pmd_mkyoung(*pmd); 856c6f3c5eeSAneesh Kumar K.V entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 857c6f3c5eeSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) 858c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 859c6f3c5eeSAneesh Kumar K.V } 860c6f3c5eeSAneesh Kumar K.V 861c6f3c5eeSAneesh Kumar K.V goto out_unlock; 862c6f3c5eeSAneesh Kumar K.V } 863c6f3c5eeSAneesh Kumar K.V 864f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 865f25748e3SDan Williams if (pfn_t_devmap(pfn)) 866f25748e3SDan Williams entry = pmd_mkdevmap(entry); 8675cad465dSMatthew Wilcox if (write) { 868f55e1014SLinus Torvalds entry = pmd_mkyoung(pmd_mkdirty(entry)); 869f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(entry, vma); 8705cad465dSMatthew Wilcox } 8713b6521f5SOliver O'Halloran 8723b6521f5SOliver O'Halloran if (pgtable) { 8733b6521f5SOliver O'Halloran pgtable_trans_huge_deposit(mm, pmd, pgtable); 874c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 875c6f3c5eeSAneesh Kumar K.V pgtable = NULL; 8763b6521f5SOliver O'Halloran } 8773b6521f5SOliver O'Halloran 8785cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 8795cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 880c6f3c5eeSAneesh Kumar K.V 881c6f3c5eeSAneesh Kumar K.V out_unlock: 8825cad465dSMatthew Wilcox spin_unlock(ptl); 883c6f3c5eeSAneesh Kumar K.V if (pgtable) 884c6f3c5eeSAneesh Kumar K.V pte_free(mm, pgtable); 8855cad465dSMatthew Wilcox } 8865cad465dSMatthew Wilcox 8879a9731b1SThomas Hellstrom (VMware) /** 8889a9731b1SThomas Hellstrom (VMware) * vmf_insert_pfn_pmd_prot - insert a pmd size pfn 8899a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 8909a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 8919a9731b1SThomas Hellstrom (VMware) * @pgprot: page protection to use 8929a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 8939a9731b1SThomas Hellstrom (VMware) * 8949a9731b1SThomas Hellstrom (VMware) * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and 8959a9731b1SThomas Hellstrom (VMware) * also consult the vmf_insert_mixed_prot() documentation when 8969a9731b1SThomas Hellstrom (VMware) * @pgprot != @vmf->vma->vm_page_prot. 8979a9731b1SThomas Hellstrom (VMware) * 8989a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 8999a9731b1SThomas Hellstrom (VMware) */ 9009a9731b1SThomas Hellstrom (VMware) vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn, 9019a9731b1SThomas Hellstrom (VMware) pgprot_t pgprot, bool write) 9025cad465dSMatthew Wilcox { 903fce86ff5SDan Williams unsigned long addr = vmf->address & PMD_MASK; 904fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 9053b6521f5SOliver O'Halloran pgtable_t pgtable = NULL; 906fce86ff5SDan Williams 9075cad465dSMatthew Wilcox /* 9085cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 9095cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 9105cad465dSMatthew Wilcox * can't support a 'special' bit. 9115cad465dSMatthew Wilcox */ 912e1fb4a08SDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 913e1fb4a08SDave Jiang !pfn_t_devmap(pfn)); 9145cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 9155cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 9165cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 9175cad465dSMatthew Wilcox 9185cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 9195cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 920308a047cSBorislav Petkov 9213b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) { 9224cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 9233b6521f5SOliver O'Halloran if (!pgtable) 9243b6521f5SOliver O'Halloran return VM_FAULT_OOM; 9253b6521f5SOliver O'Halloran } 9263b6521f5SOliver O'Halloran 927308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 928308a047cSBorislav Petkov 929fce86ff5SDan Williams insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); 930ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 9315cad465dSMatthew Wilcox } 9329a9731b1SThomas Hellstrom (VMware) EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot); 9335cad465dSMatthew Wilcox 934a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 935f55e1014SLinus Torvalds static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 936a00cc7d9SMatthew Wilcox { 937f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 938a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 939a00cc7d9SMatthew Wilcox return pud; 940a00cc7d9SMatthew Wilcox } 941a00cc7d9SMatthew Wilcox 942a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 943a00cc7d9SMatthew Wilcox pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) 944a00cc7d9SMatthew Wilcox { 945a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 946a00cc7d9SMatthew Wilcox pud_t entry; 947a00cc7d9SMatthew Wilcox spinlock_t *ptl; 948a00cc7d9SMatthew Wilcox 949a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 950c6f3c5eeSAneesh Kumar K.V if (!pud_none(*pud)) { 951c6f3c5eeSAneesh Kumar K.V if (write) { 952c6f3c5eeSAneesh Kumar K.V if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { 953c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pud(*pud)); 954c6f3c5eeSAneesh Kumar K.V goto out_unlock; 955c6f3c5eeSAneesh Kumar K.V } 956c6f3c5eeSAneesh Kumar K.V entry = pud_mkyoung(*pud); 957c6f3c5eeSAneesh Kumar K.V entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); 958c6f3c5eeSAneesh Kumar K.V if (pudp_set_access_flags(vma, addr, pud, entry, 1)) 959c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pud(vma, addr, pud); 960c6f3c5eeSAneesh Kumar K.V } 961c6f3c5eeSAneesh Kumar K.V goto out_unlock; 962c6f3c5eeSAneesh Kumar K.V } 963c6f3c5eeSAneesh Kumar K.V 964a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 965a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 966a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 967a00cc7d9SMatthew Wilcox if (write) { 968f55e1014SLinus Torvalds entry = pud_mkyoung(pud_mkdirty(entry)); 969f55e1014SLinus Torvalds entry = maybe_pud_mkwrite(entry, vma); 970a00cc7d9SMatthew Wilcox } 971a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 972a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 973c6f3c5eeSAneesh Kumar K.V 974c6f3c5eeSAneesh Kumar K.V out_unlock: 975a00cc7d9SMatthew Wilcox spin_unlock(ptl); 976a00cc7d9SMatthew Wilcox } 977a00cc7d9SMatthew Wilcox 9789a9731b1SThomas Hellstrom (VMware) /** 9799a9731b1SThomas Hellstrom (VMware) * vmf_insert_pfn_pud_prot - insert a pud size pfn 9809a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 9819a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 9829a9731b1SThomas Hellstrom (VMware) * @pgprot: page protection to use 9839a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 9849a9731b1SThomas Hellstrom (VMware) * 9859a9731b1SThomas Hellstrom (VMware) * Insert a pud size pfn. See vmf_insert_pfn() for additional info and 9869a9731b1SThomas Hellstrom (VMware) * also consult the vmf_insert_mixed_prot() documentation when 9879a9731b1SThomas Hellstrom (VMware) * @pgprot != @vmf->vma->vm_page_prot. 9889a9731b1SThomas Hellstrom (VMware) * 9899a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 9909a9731b1SThomas Hellstrom (VMware) */ 9919a9731b1SThomas Hellstrom (VMware) vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, 9929a9731b1SThomas Hellstrom (VMware) pgprot_t pgprot, bool write) 993a00cc7d9SMatthew Wilcox { 994fce86ff5SDan Williams unsigned long addr = vmf->address & PUD_MASK; 995fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 996fce86ff5SDan Williams 997a00cc7d9SMatthew Wilcox /* 998a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 999a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 1000a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 1001a00cc7d9SMatthew Wilcox */ 100262ec0d8cSDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 100362ec0d8cSDave Jiang !pfn_t_devmap(pfn)); 1004a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 1005a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 1006a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 1007a00cc7d9SMatthew Wilcox 1008a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 1009a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 1010a00cc7d9SMatthew Wilcox 1011a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 1012a00cc7d9SMatthew Wilcox 1013fce86ff5SDan Williams insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); 1014a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 1015a00cc7d9SMatthew Wilcox } 10169a9731b1SThomas Hellstrom (VMware) EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot); 1017a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1018a00cc7d9SMatthew Wilcox 10193565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 1020a69e4717SMiaohe Lin pmd_t *pmd, bool write) 10213565fce3SDan Williams { 10223565fce3SDan Williams pmd_t _pmd; 10233565fce3SDan Williams 1024a8f97366SKirill A. Shutemov _pmd = pmd_mkyoung(*pmd); 1025a69e4717SMiaohe Lin if (write) 1026a8f97366SKirill A. Shutemov _pmd = pmd_mkdirty(_pmd); 10273565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 1028a69e4717SMiaohe Lin pmd, _pmd, write)) 10293565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 10303565fce3SDan Williams } 10313565fce3SDan Williams 10323565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 1033df06b37fSKeith Busch pmd_t *pmd, int flags, struct dev_pagemap **pgmap) 10343565fce3SDan Williams { 10353565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 10363565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 10373565fce3SDan Williams struct page *page; 10380f089235SLogan Gunthorpe int ret; 10393565fce3SDan Williams 10403565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 10413565fce3SDan Williams 10423faa52c0SJohn Hubbard /* FOLL_GET and FOLL_PIN are mutually exclusive. */ 10433faa52c0SJohn Hubbard if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == 10443faa52c0SJohn Hubbard (FOLL_PIN | FOLL_GET))) 10453faa52c0SJohn Hubbard return NULL; 10463faa52c0SJohn Hubbard 1047f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pmd_write(*pmd)) 10483565fce3SDan Williams return NULL; 10493565fce3SDan Williams 10503565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 10513565fce3SDan Williams /* pass */; 10523565fce3SDan Williams else 10533565fce3SDan Williams return NULL; 10543565fce3SDan Williams 10553565fce3SDan Williams if (flags & FOLL_TOUCH) 1056a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 10573565fce3SDan Williams 10583565fce3SDan Williams /* 10593565fce3SDan Williams * device mapped pages can only be returned if the 10603565fce3SDan Williams * caller will manage the page reference count. 10613565fce3SDan Williams */ 10623faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 10633565fce3SDan Williams return ERR_PTR(-EEXIST); 10643565fce3SDan Williams 10653565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 1066df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1067df06b37fSKeith Busch if (!*pgmap) 10683565fce3SDan Williams return ERR_PTR(-EFAULT); 10693565fce3SDan Williams page = pfn_to_page(pfn); 10700f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 10710f089235SLogan Gunthorpe if (ret) 10720f089235SLogan Gunthorpe page = ERR_PTR(ret); 10733565fce3SDan Williams 10743565fce3SDan Williams return page; 10753565fce3SDan Williams } 10763565fce3SDan Williams 107771e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 107871e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 10798f34f1eaSPeter Xu struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 108071e3aac0SAndrea Arcangeli { 1081c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 108271e3aac0SAndrea Arcangeli struct page *src_page; 108371e3aac0SAndrea Arcangeli pmd_t pmd; 108412c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 1085628d47ceSKirill A. Shutemov int ret = -ENOMEM; 108671e3aac0SAndrea Arcangeli 1087628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 10888f34f1eaSPeter Xu if (!vma_is_anonymous(dst_vma)) 1089628d47ceSKirill A. Shutemov return 0; 1090628d47ceSKirill A. Shutemov 10914cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(dst_mm); 109271e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 109371e3aac0SAndrea Arcangeli goto out; 109471e3aac0SAndrea Arcangeli 1095c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 1096c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 1097c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 109871e3aac0SAndrea Arcangeli 109971e3aac0SAndrea Arcangeli ret = -EAGAIN; 110071e3aac0SAndrea Arcangeli pmd = *src_pmd; 110184c3fc4eSZi Yan 110284c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 110384c3fc4eSZi Yan if (unlikely(is_swap_pmd(pmd))) { 110484c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(pmd); 110584c3fc4eSZi Yan 110684c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(pmd)); 11076c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) { 11084dd845b5SAlistair Popple entry = make_readable_migration_entry( 11094dd845b5SAlistair Popple swp_offset(entry)); 111084c3fc4eSZi Yan pmd = swp_entry_to_pmd(entry); 1111ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*src_pmd)) 1112ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 11138f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*src_pmd)) 11148f34f1eaSPeter Xu pmd = pmd_swp_mkuffd_wp(pmd); 111584c3fc4eSZi Yan set_pmd_at(src_mm, addr, src_pmd, pmd); 111684c3fc4eSZi Yan } 1117dd8a67f9SZi Yan add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1118af5b0f6aSKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 1119dd8a67f9SZi Yan pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 11208f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11218f34f1eaSPeter Xu pmd = pmd_swp_clear_uffd_wp(pmd); 112284c3fc4eSZi Yan set_pmd_at(dst_mm, addr, dst_pmd, pmd); 112384c3fc4eSZi Yan ret = 0; 112484c3fc4eSZi Yan goto out_unlock; 112584c3fc4eSZi Yan } 112684c3fc4eSZi Yan #endif 112784c3fc4eSZi Yan 1128628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 112971e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 113071e3aac0SAndrea Arcangeli goto out_unlock; 113171e3aac0SAndrea Arcangeli } 1132fc9fe822SKirill A. Shutemov /* 1133c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 1134fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 1135fc9fe822SKirill A. Shutemov * a page table. 1136fc9fe822SKirill A. Shutemov */ 1137fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 113897ae1749SKirill A. Shutemov /* 113997ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 114097ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 114197ae1749SKirill A. Shutemov * reference. 114297ae1749SKirill A. Shutemov */ 11435fc7a5f6SPeter Xu mm_get_huge_zero_page(dst_mm); 11445fc7a5f6SPeter Xu goto out_zero_page; 1145fc9fe822SKirill A. Shutemov } 1146de466bd6SMel Gorman 114771e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 1148309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 1149d042035eSPeter Xu 1150fb3d824dSDavid Hildenbrand get_page(src_page); 1151fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { 1152fb3d824dSDavid Hildenbrand /* Page maybe pinned: split and retry the fault on PTEs. */ 1153fb3d824dSDavid Hildenbrand put_page(src_page); 1154d042035eSPeter Xu pte_free(dst_mm, pgtable); 1155d042035eSPeter Xu spin_unlock(src_ptl); 1156d042035eSPeter Xu spin_unlock(dst_ptl); 11578f34f1eaSPeter Xu __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); 1158d042035eSPeter Xu return -EAGAIN; 1159d042035eSPeter Xu } 116071e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 11615fc7a5f6SPeter Xu out_zero_page: 1162c4812909SKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 11635c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 116471e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 11658f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11668f34f1eaSPeter Xu pmd = pmd_clear_uffd_wp(pmd); 116771e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 116871e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 116971e3aac0SAndrea Arcangeli 117071e3aac0SAndrea Arcangeli ret = 0; 117171e3aac0SAndrea Arcangeli out_unlock: 1172c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 1173c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 117471e3aac0SAndrea Arcangeli out: 117571e3aac0SAndrea Arcangeli return ret; 117671e3aac0SAndrea Arcangeli } 117771e3aac0SAndrea Arcangeli 1178a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1179a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 11805fe653e9SMiaohe Lin pud_t *pud, bool write) 1181a00cc7d9SMatthew Wilcox { 1182a00cc7d9SMatthew Wilcox pud_t _pud; 1183a00cc7d9SMatthew Wilcox 1184a8f97366SKirill A. Shutemov _pud = pud_mkyoung(*pud); 11855fe653e9SMiaohe Lin if (write) 1186a8f97366SKirill A. Shutemov _pud = pud_mkdirty(_pud); 1187a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 11885fe653e9SMiaohe Lin pud, _pud, write)) 1189a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1190a00cc7d9SMatthew Wilcox } 1191a00cc7d9SMatthew Wilcox 1192a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 1193df06b37fSKeith Busch pud_t *pud, int flags, struct dev_pagemap **pgmap) 1194a00cc7d9SMatthew Wilcox { 1195a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 1196a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1197a00cc7d9SMatthew Wilcox struct page *page; 11980f089235SLogan Gunthorpe int ret; 1199a00cc7d9SMatthew Wilcox 1200a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 1201a00cc7d9SMatthew Wilcox 1202f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pud_write(*pud)) 1203a00cc7d9SMatthew Wilcox return NULL; 1204a00cc7d9SMatthew Wilcox 12053faa52c0SJohn Hubbard /* FOLL_GET and FOLL_PIN are mutually exclusive. */ 12063faa52c0SJohn Hubbard if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == 12073faa52c0SJohn Hubbard (FOLL_PIN | FOLL_GET))) 12083faa52c0SJohn Hubbard return NULL; 12093faa52c0SJohn Hubbard 1210a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 1211a00cc7d9SMatthew Wilcox /* pass */; 1212a00cc7d9SMatthew Wilcox else 1213a00cc7d9SMatthew Wilcox return NULL; 1214a00cc7d9SMatthew Wilcox 1215a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 12165fe653e9SMiaohe Lin touch_pud(vma, addr, pud, flags & FOLL_WRITE); 1217a00cc7d9SMatthew Wilcox 1218a00cc7d9SMatthew Wilcox /* 1219a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 1220a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 12213faa52c0SJohn Hubbard * 12223faa52c0SJohn Hubbard * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: 1223a00cc7d9SMatthew Wilcox */ 12243faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 1225a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 1226a00cc7d9SMatthew Wilcox 1227a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 1228df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1229df06b37fSKeith Busch if (!*pgmap) 1230a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 1231a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 12320f089235SLogan Gunthorpe 12330f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 12340f089235SLogan Gunthorpe if (ret) 12350f089235SLogan Gunthorpe page = ERR_PTR(ret); 1236a00cc7d9SMatthew Wilcox 1237a00cc7d9SMatthew Wilcox return page; 1238a00cc7d9SMatthew Wilcox } 1239a00cc7d9SMatthew Wilcox 1240a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1241a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1242a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1243a00cc7d9SMatthew Wilcox { 1244a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1245a00cc7d9SMatthew Wilcox pud_t pud; 1246a00cc7d9SMatthew Wilcox int ret; 1247a00cc7d9SMatthew Wilcox 1248a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1249a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1250a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1251a00cc7d9SMatthew Wilcox 1252a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1253a00cc7d9SMatthew Wilcox pud = *src_pud; 1254a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1255a00cc7d9SMatthew Wilcox goto out_unlock; 1256a00cc7d9SMatthew Wilcox 1257a00cc7d9SMatthew Wilcox /* 1258a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1259a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1260a00cc7d9SMatthew Wilcox * a page table. 1261a00cc7d9SMatthew Wilcox */ 1262a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1263a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1264a00cc7d9SMatthew Wilcox } 1265a00cc7d9SMatthew Wilcox 1266fb3d824dSDavid Hildenbrand /* 1267fb3d824dSDavid Hildenbrand * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() 1268fb3d824dSDavid Hildenbrand * and split if duplicating fails. 1269fb3d824dSDavid Hildenbrand */ 1270a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1271a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1272a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1273a00cc7d9SMatthew Wilcox 1274a00cc7d9SMatthew Wilcox ret = 0; 1275a00cc7d9SMatthew Wilcox out_unlock: 1276a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1277a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1278a00cc7d9SMatthew Wilcox return ret; 1279a00cc7d9SMatthew Wilcox } 1280a00cc7d9SMatthew Wilcox 1281a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1282a00cc7d9SMatthew Wilcox { 1283a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1284a00cc7d9SMatthew Wilcox 1285a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1286a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1287a00cc7d9SMatthew Wilcox goto unlock; 1288a00cc7d9SMatthew Wilcox 12895fe653e9SMiaohe Lin touch_pud(vmf->vma, vmf->address, vmf->pud, write); 1290a00cc7d9SMatthew Wilcox unlock: 1291a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1292a00cc7d9SMatthew Wilcox } 1293a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1294a00cc7d9SMatthew Wilcox 12955db4f15cSYang Shi void huge_pmd_set_accessed(struct vm_fault *vmf) 1296a1dd450bSWill Deacon { 129720f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1298a1dd450bSWill Deacon 129982b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 1300a69e4717SMiaohe Lin if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) 1301a1dd450bSWill Deacon goto unlock; 1302a1dd450bSWill Deacon 1303a69e4717SMiaohe Lin touch_pmd(vmf->vma, vmf->address, vmf->pmd, write); 1304a1dd450bSWill Deacon 1305a1dd450bSWill Deacon unlock: 130682b0f8c3SJan Kara spin_unlock(vmf->ptl); 1307a1dd450bSWill Deacon } 1308a1dd450bSWill Deacon 13095db4f15cSYang Shi vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) 131071e3aac0SAndrea Arcangeli { 1311c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 131282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 13132fad3d14SMatthew Wilcox (Oracle) struct folio *folio; 13143917c802SKirill A. Shutemov struct page *page; 131582b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 13165db4f15cSYang Shi pmd_t orig_pmd = vmf->orig_pmd; 131771e3aac0SAndrea Arcangeli 131882b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 131981d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 13203917c802SKirill A. Shutemov 132193b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 13223917c802SKirill A. Shutemov goto fallback; 13233917c802SKirill A. Shutemov 132482b0f8c3SJan Kara spin_lock(vmf->ptl); 13253917c802SKirill A. Shutemov 13263917c802SKirill A. Shutemov if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13273917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13283917c802SKirill A. Shutemov return 0; 13293917c802SKirill A. Shutemov } 133071e3aac0SAndrea Arcangeli 133171e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 13322fad3d14SMatthew Wilcox (Oracle) folio = page_folio(page); 1333f6004e73SMiaohe Lin VM_BUG_ON_PAGE(!PageHead(page), page); 13343917c802SKirill A. Shutemov 13356c287605SDavid Hildenbrand /* Early check when only holding the PT lock. */ 13366c287605SDavid Hildenbrand if (PageAnonExclusive(page)) 13376c287605SDavid Hildenbrand goto reuse; 13386c287605SDavid Hildenbrand 13392fad3d14SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) { 13402fad3d14SMatthew Wilcox (Oracle) folio_get(folio); 1341ba3c4ce6SHuang Ying spin_unlock(vmf->ptl); 13422fad3d14SMatthew Wilcox (Oracle) folio_lock(folio); 1343ba3c4ce6SHuang Ying spin_lock(vmf->ptl); 1344ba3c4ce6SHuang Ying if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13453917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13462fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13472fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 13483917c802SKirill A. Shutemov return 0; 1349ba3c4ce6SHuang Ying } 13502fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 1351ba3c4ce6SHuang Ying } 13523917c802SKirill A. Shutemov 13536c287605SDavid Hildenbrand /* Recheck after temporarily dropping the PT lock. */ 13546c287605SDavid Hildenbrand if (PageAnonExclusive(page)) { 13552fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13566c287605SDavid Hildenbrand goto reuse; 13576c287605SDavid Hildenbrand } 13586c287605SDavid Hildenbrand 13593917c802SKirill A. Shutemov /* 13602fad3d14SMatthew Wilcox (Oracle) * See do_wp_page(): we can only reuse the folio exclusively if 13612fad3d14SMatthew Wilcox (Oracle) * there are no additional references. Note that we always drain 13622fad3d14SMatthew Wilcox (Oracle) * the LRU pagevecs immediately after adding a THP. 13633917c802SKirill A. Shutemov */ 13642fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) > 13652fad3d14SMatthew Wilcox (Oracle) 1 + folio_test_swapcache(folio) * folio_nr_pages(folio)) 13663bff7e3fSDavid Hildenbrand goto unlock_fallback; 13672fad3d14SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 13682fad3d14SMatthew Wilcox (Oracle) folio_free_swap(folio); 13692fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) == 1) { 137071e3aac0SAndrea Arcangeli pmd_t entry; 13716c54dc6cSDavid Hildenbrand 13726c54dc6cSDavid Hildenbrand page_move_anon_rmap(page, vma); 13732fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13746c287605SDavid Hildenbrand reuse: 1375c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 1376c89357e2SDavid Hildenbrand spin_unlock(vmf->ptl); 1377c89357e2SDavid Hildenbrand return 0; 1378c89357e2SDavid Hildenbrand } 137971e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 1380f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 138182b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 138282b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 13833917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 1384cb8d8633SDavid Hildenbrand return 0; 138571e3aac0SAndrea Arcangeli } 13863917c802SKirill A. Shutemov 13873bff7e3fSDavid Hildenbrand unlock_fallback: 13882fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 138982b0f8c3SJan Kara spin_unlock(vmf->ptl); 13903917c802SKirill A. Shutemov fallback: 13913917c802SKirill A. Shutemov __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); 13923917c802SKirill A. Shutemov return VM_FAULT_FALLBACK; 139371e3aac0SAndrea Arcangeli } 139471e3aac0SAndrea Arcangeli 1395c27f479eSDavid Hildenbrand static inline bool can_change_pmd_writable(struct vm_area_struct *vma, 1396c27f479eSDavid Hildenbrand unsigned long addr, pmd_t pmd) 1397c27f479eSDavid Hildenbrand { 1398c27f479eSDavid Hildenbrand struct page *page; 1399c27f479eSDavid Hildenbrand 1400c27f479eSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) 1401c27f479eSDavid Hildenbrand return false; 1402c27f479eSDavid Hildenbrand 1403c27f479eSDavid Hildenbrand /* Don't touch entries that are not even readable (NUMA hinting). */ 1404c27f479eSDavid Hildenbrand if (pmd_protnone(pmd)) 1405c27f479eSDavid Hildenbrand return false; 1406c27f479eSDavid Hildenbrand 1407c27f479eSDavid Hildenbrand /* Do we need write faults for softdirty tracking? */ 1408c27f479eSDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 1409c27f479eSDavid Hildenbrand return false; 1410c27f479eSDavid Hildenbrand 1411c27f479eSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 1412c27f479eSDavid Hildenbrand if (userfaultfd_huge_pmd_wp(vma, pmd)) 1413c27f479eSDavid Hildenbrand return false; 1414c27f479eSDavid Hildenbrand 1415c27f479eSDavid Hildenbrand if (!(vma->vm_flags & VM_SHARED)) { 1416c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1417c27f479eSDavid Hildenbrand page = vm_normal_page_pmd(vma, addr, pmd); 1418c27f479eSDavid Hildenbrand return page && PageAnon(page) && PageAnonExclusive(page); 1419c27f479eSDavid Hildenbrand } 1420c27f479eSDavid Hildenbrand 1421c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1422c27f479eSDavid Hildenbrand return pmd_dirty(pmd); 1423c27f479eSDavid Hildenbrand } 1424c27f479eSDavid Hildenbrand 14255535be30SDavid Hildenbrand /* FOLL_FORCE can write to even unwritable PMDs in COW mappings. */ 14265535be30SDavid Hildenbrand static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, 14275535be30SDavid Hildenbrand struct vm_area_struct *vma, 14285535be30SDavid Hildenbrand unsigned int flags) 14298310d48bSKeno Fischer { 14305535be30SDavid Hildenbrand /* If the pmd is writable, we can write to the page. */ 14315535be30SDavid Hildenbrand if (pmd_write(pmd)) 14325535be30SDavid Hildenbrand return true; 14335535be30SDavid Hildenbrand 14345535be30SDavid Hildenbrand /* Maybe FOLL_FORCE is set to override it? */ 14355535be30SDavid Hildenbrand if (!(flags & FOLL_FORCE)) 14365535be30SDavid Hildenbrand return false; 14375535be30SDavid Hildenbrand 14385535be30SDavid Hildenbrand /* But FOLL_FORCE has no effect on shared mappings */ 14395535be30SDavid Hildenbrand if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED)) 14405535be30SDavid Hildenbrand return false; 14415535be30SDavid Hildenbrand 14425535be30SDavid Hildenbrand /* ... or read-only private ones */ 14435535be30SDavid Hildenbrand if (!(vma->vm_flags & VM_MAYWRITE)) 14445535be30SDavid Hildenbrand return false; 14455535be30SDavid Hildenbrand 14465535be30SDavid Hildenbrand /* ... or already writable ones that just need to take a write fault */ 14475535be30SDavid Hildenbrand if (vma->vm_flags & VM_WRITE) 14485535be30SDavid Hildenbrand return false; 14495535be30SDavid Hildenbrand 14505535be30SDavid Hildenbrand /* 14515535be30SDavid Hildenbrand * See can_change_pte_writable(): we broke COW and could map the page 14525535be30SDavid Hildenbrand * writable if we have an exclusive anonymous page ... 14535535be30SDavid Hildenbrand */ 14545535be30SDavid Hildenbrand if (!page || !PageAnon(page) || !PageAnonExclusive(page)) 14555535be30SDavid Hildenbrand return false; 14565535be30SDavid Hildenbrand 14575535be30SDavid Hildenbrand /* ... and a write-fault isn't required for other reasons. */ 14585535be30SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 14595535be30SDavid Hildenbrand return false; 14605535be30SDavid Hildenbrand return !userfaultfd_huge_pmd_wp(vma, pmd); 14618310d48bSKeno Fischer } 14628310d48bSKeno Fischer 1463b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 146471e3aac0SAndrea Arcangeli unsigned long addr, 146571e3aac0SAndrea Arcangeli pmd_t *pmd, 146671e3aac0SAndrea Arcangeli unsigned int flags) 146771e3aac0SAndrea Arcangeli { 1468b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 14695535be30SDavid Hildenbrand struct page *page; 14700f089235SLogan Gunthorpe int ret; 147171e3aac0SAndrea Arcangeli 1472c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 147371e3aac0SAndrea Arcangeli 14745535be30SDavid Hildenbrand page = pmd_page(*pmd); 14755535be30SDavid Hildenbrand VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 14765535be30SDavid Hildenbrand 14775535be30SDavid Hildenbrand if ((flags & FOLL_WRITE) && 14785535be30SDavid Hildenbrand !can_follow_write_pmd(*pmd, page, vma, flags)) 14795535be30SDavid Hildenbrand return NULL; 148071e3aac0SAndrea Arcangeli 148185facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 148285facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 148385facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 148485facf25SKirill A. Shutemov 14852b4847e7SMel Gorman /* Full NUMA hinting faults to serialise migration in fault paths */ 1486474098edSDavid Hildenbrand if (pmd_protnone(*pmd) && !gup_can_follow_protnone(flags)) 14875535be30SDavid Hildenbrand return NULL; 14883faa52c0SJohn Hubbard 148984209e87SDavid Hildenbrand if (!pmd_write(*pmd) && gup_must_unshare(vma, flags, page)) 1490a7f22660SDavid Hildenbrand return ERR_PTR(-EMLINK); 1491a7f22660SDavid Hildenbrand 1492b6a2619cSDavid Hildenbrand VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && 1493b6a2619cSDavid Hildenbrand !PageAnonExclusive(page), page); 1494b6a2619cSDavid Hildenbrand 14950f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 14960f089235SLogan Gunthorpe if (ret) 14970f089235SLogan Gunthorpe return ERR_PTR(ret); 14983faa52c0SJohn Hubbard 14993565fce3SDan Williams if (flags & FOLL_TOUCH) 1500a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 15013faa52c0SJohn Hubbard 150271e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1503ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 150471e3aac0SAndrea Arcangeli 150571e3aac0SAndrea Arcangeli return page; 150671e3aac0SAndrea Arcangeli } 150771e3aac0SAndrea Arcangeli 1508d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 15095db4f15cSYang Shi vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) 1510d10e63f2SMel Gorman { 151182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1512c5b5a3ddSYang Shi pmd_t oldpmd = vmf->orig_pmd; 1513c5b5a3ddSYang Shi pmd_t pmd; 1514b32967ffSMel Gorman struct page *page; 151582b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 1516c5b5a3ddSYang Shi int page_nid = NUMA_NO_NODE; 151733024536SHuang Ying int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); 15186a56ccbcSDavid Hildenbrand bool migrated = false, writable = false; 15196688cc05SPeter Zijlstra int flags = 0; 1520d10e63f2SMel Gorman 152182b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1522c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 152382b0f8c3SJan Kara spin_unlock(vmf->ptl); 1524de466bd6SMel Gorman goto out; 1525de466bd6SMel Gorman } 1526de466bd6SMel Gorman 1527c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 15286a56ccbcSDavid Hildenbrand 15296a56ccbcSDavid Hildenbrand /* 15306a56ccbcSDavid Hildenbrand * Detect now whether the PMD could be writable; this information 15316a56ccbcSDavid Hildenbrand * is only valid while holding the PT lock. 15326a56ccbcSDavid Hildenbrand */ 15336a56ccbcSDavid Hildenbrand writable = pmd_write(pmd); 15346a56ccbcSDavid Hildenbrand if (!writable && vma_wants_manual_pte_write_upgrade(vma) && 15356a56ccbcSDavid Hildenbrand can_change_pmd_writable(vma, vmf->address, pmd)) 15366a56ccbcSDavid Hildenbrand writable = true; 15376a56ccbcSDavid Hildenbrand 1538c5b5a3ddSYang Shi page = vm_normal_page_pmd(vma, haddr, pmd); 1539c5b5a3ddSYang Shi if (!page) 1540c5b5a3ddSYang Shi goto out_map; 1541c5b5a3ddSYang Shi 1542c5b5a3ddSYang Shi /* See similar comment in do_numa_page for explanation */ 15436a56ccbcSDavid Hildenbrand if (!writable) 1544c5b5a3ddSYang Shi flags |= TNF_NO_GROUP; 1545c5b5a3ddSYang Shi 1546c5b5a3ddSYang Shi page_nid = page_to_nid(page); 154733024536SHuang Ying /* 154833024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 154933024536SHuang Ying * to record page access time. So use default value. 155033024536SHuang Ying */ 155133024536SHuang Ying if (node_is_toptier(page_nid)) 1552c5b5a3ddSYang Shi last_cpupid = page_cpupid_last(page); 1553c5b5a3ddSYang Shi target_nid = numa_migrate_prep(page, vma, haddr, page_nid, 1554c5b5a3ddSYang Shi &flags); 1555c5b5a3ddSYang Shi 1556c5b5a3ddSYang Shi if (target_nid == NUMA_NO_NODE) { 1557c5b5a3ddSYang Shi put_page(page); 1558c5b5a3ddSYang Shi goto out_map; 1559c5b5a3ddSYang Shi } 1560c5b5a3ddSYang Shi 156182b0f8c3SJan Kara spin_unlock(vmf->ptl); 15626a56ccbcSDavid Hildenbrand writable = false; 15638b1b436dSPeter Zijlstra 1564c5b5a3ddSYang Shi migrated = migrate_misplaced_page(page, vma, target_nid); 15656688cc05SPeter Zijlstra if (migrated) { 15666688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 15678191acbdSMel Gorman page_nid = target_nid; 1568c5b5a3ddSYang Shi } else { 1569074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1570c5b5a3ddSYang Shi vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1571c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 157282b0f8c3SJan Kara spin_unlock(vmf->ptl); 1573c5b5a3ddSYang Shi goto out; 1574c5b5a3ddSYang Shi } 1575c5b5a3ddSYang Shi goto out_map; 1576c5b5a3ddSYang Shi } 1577b8916634SMel Gorman 1578b8916634SMel Gorman out: 157998fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 158082b0f8c3SJan Kara task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, 15819a8b300fSAneesh Kumar K.V flags); 15828191acbdSMel Gorman 1583d10e63f2SMel Gorman return 0; 1584c5b5a3ddSYang Shi 1585c5b5a3ddSYang Shi out_map: 1586c5b5a3ddSYang Shi /* Restore the PMD */ 1587c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 1588c5b5a3ddSYang Shi pmd = pmd_mkyoung(pmd); 15896a56ccbcSDavid Hildenbrand if (writable) 1590c5b5a3ddSYang Shi pmd = pmd_mkwrite(pmd); 1591c5b5a3ddSYang Shi set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 1592c5b5a3ddSYang Shi update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1593c5b5a3ddSYang Shi spin_unlock(vmf->ptl); 1594c5b5a3ddSYang Shi goto out; 1595d10e63f2SMel Gorman } 1596d10e63f2SMel Gorman 1597319904adSHuang Ying /* 1598319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1599319904adSHuang Ying * Otherwise, return false. 1600319904adSHuang Ying */ 1601319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1602b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1603b8d3c4c3SMinchan Kim { 1604b8d3c4c3SMinchan Kim spinlock_t *ptl; 1605b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1606fc986a38SKefeng Wang struct folio *folio; 1607b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1608319904adSHuang Ying bool ret = false; 1609b8d3c4c3SMinchan Kim 1610ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 161107e32661SAneesh Kumar K.V 1612b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1613b6ec57f4SKirill A. Shutemov if (!ptl) 161425eedabeSLinus Torvalds goto out_unlocked; 1615b8d3c4c3SMinchan Kim 1616b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1617319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1618b8d3c4c3SMinchan Kim goto out; 1619b8d3c4c3SMinchan Kim 162084c3fc4eSZi Yan if (unlikely(!pmd_present(orig_pmd))) { 162184c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 162284c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 162384c3fc4eSZi Yan goto out; 162484c3fc4eSZi Yan } 162584c3fc4eSZi Yan 1626fc986a38SKefeng Wang folio = pfn_folio(pmd_pfn(orig_pmd)); 1627b8d3c4c3SMinchan Kim /* 1628fc986a38SKefeng Wang * If other processes are mapping this folio, we couldn't discard 1629fc986a38SKefeng Wang * the folio unless they all do MADV_FREE so let's skip the folio. 1630b8d3c4c3SMinchan Kim */ 1631fc986a38SKefeng Wang if (folio_mapcount(folio) != 1) 1632b8d3c4c3SMinchan Kim goto out; 1633b8d3c4c3SMinchan Kim 1634fc986a38SKefeng Wang if (!folio_trylock(folio)) 1635b8d3c4c3SMinchan Kim goto out; 1636b8d3c4c3SMinchan Kim 1637b8d3c4c3SMinchan Kim /* 1638b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1639b8d3c4c3SMinchan Kim * will deactivate only them. 1640b8d3c4c3SMinchan Kim */ 1641b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1642fc986a38SKefeng Wang folio_get(folio); 1643b8d3c4c3SMinchan Kim spin_unlock(ptl); 1644fc986a38SKefeng Wang split_folio(folio); 1645fc986a38SKefeng Wang folio_unlock(folio); 1646fc986a38SKefeng Wang folio_put(folio); 1647b8d3c4c3SMinchan Kim goto out_unlocked; 1648b8d3c4c3SMinchan Kim } 1649b8d3c4c3SMinchan Kim 1650fc986a38SKefeng Wang if (folio_test_dirty(folio)) 1651fc986a38SKefeng Wang folio_clear_dirty(folio); 1652fc986a38SKefeng Wang folio_unlock(folio); 1653b8d3c4c3SMinchan Kim 1654b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 165558ceeb6bSKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1656b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1657b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1658b8d3c4c3SMinchan Kim 1659b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1660b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1661b8d3c4c3SMinchan Kim } 1662802a3a92SShaohua Li 1663*6a6fe9ebSKefeng Wang folio_mark_lazyfree(folio); 1664319904adSHuang Ying ret = true; 1665b8d3c4c3SMinchan Kim out: 1666b8d3c4c3SMinchan Kim spin_unlock(ptl); 1667b8d3c4c3SMinchan Kim out_unlocked: 1668b8d3c4c3SMinchan Kim return ret; 1669b8d3c4c3SMinchan Kim } 1670b8d3c4c3SMinchan Kim 1671953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1672953c66c2SAneesh Kumar K.V { 1673953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1674953c66c2SAneesh Kumar K.V 1675953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1676953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1677c4812909SKirill A. Shutemov mm_dec_nr_ptes(mm); 1678953c66c2SAneesh Kumar K.V } 1679953c66c2SAneesh Kumar K.V 168071e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1681f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 168271e3aac0SAndrea Arcangeli { 1683f5c8ad47SDavid Miller pmd_t orig_pmd; 1684da146769SKirill A. Shutemov spinlock_t *ptl; 1685da146769SKirill A. Shutemov 1686ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 168707e32661SAneesh Kumar K.V 1688b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1689b6ec57f4SKirill A. Shutemov if (!ptl) 1690da146769SKirill A. Shutemov return 0; 1691a6bf2bb0SAneesh Kumar K.V /* 1692a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 16938809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1694a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1695a6bf2bb0SAneesh Kumar K.V * operations. 1696a6bf2bb0SAneesh Kumar K.V */ 169793a98695SAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, 1698fcbe08d6SMartin Schwidefsky tlb->fullmm); 1699f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 17002484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 17013b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) 17023b6521f5SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 17034897c765SMatthew Wilcox spin_unlock(ptl); 1704da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1705c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1706bf929152SKirill A. Shutemov spin_unlock(ptl); 1707479f0abbSKirill A. Shutemov } else { 1708616b8371SZi Yan struct page *page = NULL; 1709616b8371SZi Yan int flush_needed = 1; 1710616b8371SZi Yan 1711616b8371SZi Yan if (pmd_present(orig_pmd)) { 1712616b8371SZi Yan page = pmd_page(orig_pmd); 1713cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 1714309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1715309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1716616b8371SZi Yan } else if (thp_migration_supported()) { 1717616b8371SZi Yan swp_entry_t entry; 1718616b8371SZi Yan 1719616b8371SZi Yan VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); 1720616b8371SZi Yan entry = pmd_to_swp_entry(orig_pmd); 1721af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1722616b8371SZi Yan flush_needed = 0; 1723616b8371SZi Yan } else 1724616b8371SZi Yan WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); 1725616b8371SZi Yan 1726b5072380SKirill A. Shutemov if (PageAnon(page)) { 1727c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1728b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1729b5072380SKirill A. Shutemov } else { 1730953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1731953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1732fadae295SYang Shi add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); 1733b5072380SKirill A. Shutemov } 1734616b8371SZi Yan 1735bf929152SKirill A. Shutemov spin_unlock(ptl); 1736616b8371SZi Yan if (flush_needed) 1737e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1738479f0abbSKirill A. Shutemov } 1739da146769SKirill A. Shutemov return 1; 174071e3aac0SAndrea Arcangeli } 174171e3aac0SAndrea Arcangeli 17421dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 17431dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 17441dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 17451dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 17461dd38b6cSAneesh Kumar K.V { 17471dd38b6cSAneesh Kumar K.V /* 17481dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 17491dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 17501dd38b6cSAneesh Kumar K.V * 17511dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 17521dd38b6cSAneesh Kumar K.V */ 17531dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 17541dd38b6cSAneesh Kumar K.V } 17551dd38b6cSAneesh Kumar K.V #endif 17561dd38b6cSAneesh Kumar K.V 1757ab6e3d09SNaoya Horiguchi static pmd_t move_soft_dirty_pmd(pmd_t pmd) 1758ab6e3d09SNaoya Horiguchi { 1759ab6e3d09SNaoya Horiguchi #ifdef CONFIG_MEM_SOFT_DIRTY 1760ab6e3d09SNaoya Horiguchi if (unlikely(is_pmd_migration_entry(pmd))) 1761ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 1762ab6e3d09SNaoya Horiguchi else if (pmd_present(pmd)) 1763ab6e3d09SNaoya Horiguchi pmd = pmd_mksoft_dirty(pmd); 1764ab6e3d09SNaoya Horiguchi #endif 1765ab6e3d09SNaoya Horiguchi return pmd; 1766ab6e3d09SNaoya Horiguchi } 1767ab6e3d09SNaoya Horiguchi 1768bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 1769b8aa9d9dSWei Yang unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) 177037a1c49aSAndrea Arcangeli { 1771bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 177237a1c49aSAndrea Arcangeli pmd_t pmd; 177337a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 17745d190420SAaron Lu bool force_flush = false; 177537a1c49aSAndrea Arcangeli 177637a1c49aSAndrea Arcangeli /* 177737a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 177837a1c49aSAndrea Arcangeli * should have release it. 177937a1c49aSAndrea Arcangeli */ 178037a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 178137a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 17824b471e88SKirill A. Shutemov return false; 178337a1c49aSAndrea Arcangeli } 178437a1c49aSAndrea Arcangeli 1785bf929152SKirill A. Shutemov /* 1786bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1787c1e8d7c6SMichel Lespinasse * ptlocks because exclusive mmap_lock prevents deadlock. 1788bf929152SKirill A. Shutemov */ 1789b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1790b6ec57f4SKirill A. Shutemov if (old_ptl) { 1791bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1792bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1793bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 17948809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1795eb66ae03SLinus Torvalds if (pmd_present(pmd)) 1796a2ce2666SAaron Lu force_flush = true; 179737a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 17983592806cSKirill A. Shutemov 17991dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1800b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 18013592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 18023592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 18033592806cSKirill A. Shutemov } 1804ab6e3d09SNaoya Horiguchi pmd = move_soft_dirty_pmd(pmd); 1805ab6e3d09SNaoya Horiguchi set_pmd_at(mm, new_addr, new_pmd, pmd); 18065d190420SAaron Lu if (force_flush) 18077c38f181SMiaohe Lin flush_pmd_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 1808eb66ae03SLinus Torvalds if (new_ptl != old_ptl) 1809eb66ae03SLinus Torvalds spin_unlock(new_ptl); 1810bf929152SKirill A. Shutemov spin_unlock(old_ptl); 18114b471e88SKirill A. Shutemov return true; 181237a1c49aSAndrea Arcangeli } 18134b471e88SKirill A. Shutemov return false; 181437a1c49aSAndrea Arcangeli } 181537a1c49aSAndrea Arcangeli 1816f123d74aSMel Gorman /* 1817f123d74aSMel Gorman * Returns 1818f123d74aSMel Gorman * - 0 if PMD could not be locked 1819f0953a1bSIngo Molnar * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary 1820e346e668SYang Shi * or if prot_numa but THP migration is not supported 1821f0953a1bSIngo Molnar * - HPAGE_PMD_NR if protections changed and TLB flush necessary 1822f123d74aSMel Gorman */ 18234a18419fSNadav Amit int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 18244a18419fSNadav Amit pmd_t *pmd, unsigned long addr, pgprot_t newprot, 18254a18419fSNadav Amit unsigned long cp_flags) 1826cd7548abSJohannes Weiner { 1827cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1828bf929152SKirill A. Shutemov spinlock_t *ptl; 1829c9fe6656SNadav Amit pmd_t oldpmd, entry; 183058705444SPeter Xu bool prot_numa = cp_flags & MM_CP_PROT_NUMA; 1831292924b2SPeter Xu bool uffd_wp = cp_flags & MM_CP_UFFD_WP; 1832292924b2SPeter Xu bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; 18336a56ccbcSDavid Hildenbrand int ret = 1; 1834cd7548abSJohannes Weiner 18354a18419fSNadav Amit tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 18364a18419fSNadav Amit 1837e346e668SYang Shi if (prot_numa && !thp_migration_supported()) 1838e346e668SYang Shi return 1; 1839e346e668SYang Shi 1840b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 18410a85e51dSKirill A. Shutemov if (!ptl) 18420a85e51dSKirill A. Shutemov return 0; 18430a85e51dSKirill A. Shutemov 184484c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 184584c3fc4eSZi Yan if (is_swap_pmd(*pmd)) { 184684c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(*pmd); 18476c287605SDavid Hildenbrand struct page *page = pfn_swap_entry_to_page(entry); 184884c3fc4eSZi Yan 184984c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd)); 18504dd845b5SAlistair Popple if (is_writable_migration_entry(entry)) { 185184c3fc4eSZi Yan pmd_t newpmd; 185284c3fc4eSZi Yan /* 185384c3fc4eSZi Yan * A protection check is difficult so 185484c3fc4eSZi Yan * just be safe and disable write 185584c3fc4eSZi Yan */ 18566c287605SDavid Hildenbrand if (PageAnon(page)) 18576c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(swp_offset(entry)); 18586c287605SDavid Hildenbrand else 18596c287605SDavid Hildenbrand entry = make_readable_migration_entry(swp_offset(entry)); 186084c3fc4eSZi Yan newpmd = swp_entry_to_pmd(entry); 1861ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pmd)) 1862ab6e3d09SNaoya Horiguchi newpmd = pmd_swp_mksoft_dirty(newpmd); 18638f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*pmd)) 18648f34f1eaSPeter Xu newpmd = pmd_swp_mkuffd_wp(newpmd); 186584c3fc4eSZi Yan set_pmd_at(mm, addr, pmd, newpmd); 186684c3fc4eSZi Yan } 186784c3fc4eSZi Yan goto unlock; 186884c3fc4eSZi Yan } 186984c3fc4eSZi Yan #endif 187084c3fc4eSZi Yan 1871a1a3a2fcSHuang Ying if (prot_numa) { 1872a1a3a2fcSHuang Ying struct page *page; 187333024536SHuang Ying bool toptier; 1874e944fd67SMel Gorman /* 1875e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1876e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1877e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1878e944fd67SMel Gorman */ 1879a1a3a2fcSHuang Ying if (is_huge_zero_pmd(*pmd)) 18800a85e51dSKirill A. Shutemov goto unlock; 1881e944fd67SMel Gorman 1882a1a3a2fcSHuang Ying if (pmd_protnone(*pmd)) 18830a85e51dSKirill A. Shutemov goto unlock; 18840a85e51dSKirill A. Shutemov 1885a1a3a2fcSHuang Ying page = pmd_page(*pmd); 188633024536SHuang Ying toptier = node_is_toptier(page_to_nid(page)); 1887a1a3a2fcSHuang Ying /* 1888a1a3a2fcSHuang Ying * Skip scanning top tier node if normal numa 1889a1a3a2fcSHuang Ying * balancing is disabled 1890a1a3a2fcSHuang Ying */ 1891a1a3a2fcSHuang Ying if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && 189233024536SHuang Ying toptier) 1893a1a3a2fcSHuang Ying goto unlock; 189433024536SHuang Ying 189533024536SHuang Ying if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && 189633024536SHuang Ying !toptier) 189733024536SHuang Ying xchg_page_access_time(page, jiffies_to_msecs(jiffies)); 1898a1a3a2fcSHuang Ying } 1899ced10803SKirill A. Shutemov /* 19003e4e28c5SMichel Lespinasse * In case prot_numa, we are under mmap_read_lock(mm). It's critical 1901ced10803SKirill A. Shutemov * to not clear pmd intermittently to avoid race with MADV_DONTNEED 19023e4e28c5SMichel Lespinasse * which is also under mmap_read_lock(mm): 1903ced10803SKirill A. Shutemov * 1904ced10803SKirill A. Shutemov * CPU0: CPU1: 1905ced10803SKirill A. Shutemov * change_huge_pmd(prot_numa=1) 1906ced10803SKirill A. Shutemov * pmdp_huge_get_and_clear_notify() 1907ced10803SKirill A. Shutemov * madvise_dontneed() 1908ced10803SKirill A. Shutemov * zap_pmd_range() 1909ced10803SKirill A. Shutemov * pmd_trans_huge(*pmd) == 0 (without ptl) 1910ced10803SKirill A. Shutemov * // skip the pmd 1911ced10803SKirill A. Shutemov * set_pmd_at(); 1912ced10803SKirill A. Shutemov * // pmd is re-established 1913ced10803SKirill A. Shutemov * 1914ced10803SKirill A. Shutemov * The race makes MADV_DONTNEED miss the huge pmd and don't clear it 1915ced10803SKirill A. Shutemov * which may break userspace. 1916ced10803SKirill A. Shutemov * 19174f831457SNadav Amit * pmdp_invalidate_ad() is required to make sure we don't miss 1918ced10803SKirill A. Shutemov * dirty/young flags set by hardware. 1919ced10803SKirill A. Shutemov */ 19204f831457SNadav Amit oldpmd = pmdp_invalidate_ad(vma, addr, pmd); 1921ced10803SKirill A. Shutemov 1922c9fe6656SNadav Amit entry = pmd_modify(oldpmd, newprot); 1923f1eb1bacSPeter Xu if (uffd_wp) 1924292924b2SPeter Xu entry = pmd_mkuffd_wp(entry); 1925f1eb1bacSPeter Xu else if (uffd_wp_resolve) 1926292924b2SPeter Xu /* 1927292924b2SPeter Xu * Leave the write bit to be handled by PF interrupt 1928292924b2SPeter Xu * handler, then things like COW could be properly 1929292924b2SPeter Xu * handled. 1930292924b2SPeter Xu */ 1931292924b2SPeter Xu entry = pmd_clear_uffd_wp(entry); 1932c27f479eSDavid Hildenbrand 1933c27f479eSDavid Hildenbrand /* See change_pte_range(). */ 1934c27f479eSDavid Hildenbrand if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && !pmd_write(entry) && 1935c27f479eSDavid Hildenbrand can_change_pmd_writable(vma, addr, entry)) 1936c27f479eSDavid Hildenbrand entry = pmd_mkwrite(entry); 1937c27f479eSDavid Hildenbrand 1938f123d74aSMel Gorman ret = HPAGE_PMD_NR; 193956eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 19404a18419fSNadav Amit 1941c9fe6656SNadav Amit if (huge_pmd_needs_flush(oldpmd, entry)) 19424a18419fSNadav Amit tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); 19430a85e51dSKirill A. Shutemov unlock: 1944bf929152SKirill A. Shutemov spin_unlock(ptl); 1945cd7548abSJohannes Weiner return ret; 1946cd7548abSJohannes Weiner } 1947cd7548abSJohannes Weiner 1948025c5b24SNaoya Horiguchi /* 19498f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 1950025c5b24SNaoya Horiguchi * 19518f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 19528f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 1953025c5b24SNaoya Horiguchi */ 1954b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1955025c5b24SNaoya Horiguchi { 1956b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 1957b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 195884c3fc4eSZi Yan if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || 195984c3fc4eSZi Yan pmd_devmap(*pmd))) 1960b6ec57f4SKirill A. Shutemov return ptl; 1961b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 1962b6ec57f4SKirill A. Shutemov return NULL; 1963025c5b24SNaoya Horiguchi } 1964025c5b24SNaoya Horiguchi 1965a00cc7d9SMatthew Wilcox /* 1966d965e390SMiaohe Lin * Returns page table lock pointer if a given pud maps a thp, NULL otherwise. 1967a00cc7d9SMatthew Wilcox * 1968d965e390SMiaohe Lin * Note that if it returns page table lock pointer, this routine returns without 1969d965e390SMiaohe Lin * unlocking page table lock. So callers must unlock it. 1970a00cc7d9SMatthew Wilcox */ 1971a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 1972a00cc7d9SMatthew Wilcox { 1973a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1974a00cc7d9SMatthew Wilcox 1975a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 1976a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 1977a00cc7d9SMatthew Wilcox return ptl; 1978a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1979a00cc7d9SMatthew Wilcox return NULL; 1980a00cc7d9SMatthew Wilcox } 1981a00cc7d9SMatthew Wilcox 1982a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1983a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 1984a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 1985a00cc7d9SMatthew Wilcox { 1986a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1987a00cc7d9SMatthew Wilcox 1988a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 1989a00cc7d9SMatthew Wilcox if (!ptl) 1990a00cc7d9SMatthew Wilcox return 0; 199174929079SMiaohe Lin 199270516b93SQian Cai pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); 1993a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 19942484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 1995a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1996a00cc7d9SMatthew Wilcox /* No zero page support yet */ 1997a00cc7d9SMatthew Wilcox } else { 1998a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 1999a00cc7d9SMatthew Wilcox BUG(); 2000a00cc7d9SMatthew Wilcox } 2001a00cc7d9SMatthew Wilcox return 1; 2002a00cc7d9SMatthew Wilcox } 2003a00cc7d9SMatthew Wilcox 2004a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 2005a00cc7d9SMatthew Wilcox unsigned long haddr) 2006a00cc7d9SMatthew Wilcox { 2007a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 2008a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2009a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 2010a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 2011a00cc7d9SMatthew Wilcox 2012ce9311cfSYisheng Xie count_vm_event(THP_SPLIT_PUD); 2013a00cc7d9SMatthew Wilcox 2014a00cc7d9SMatthew Wilcox pudp_huge_clear_flush_notify(vma, haddr, pud); 2015a00cc7d9SMatthew Wilcox } 2016a00cc7d9SMatthew Wilcox 2017a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 2018a00cc7d9SMatthew Wilcox unsigned long address) 2019a00cc7d9SMatthew Wilcox { 2020a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2021ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2022a00cc7d9SMatthew Wilcox 20237269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 20246f4f13e8SJérôme Glisse address & HPAGE_PUD_MASK, 2025ac46d4f3SJérôme Glisse (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); 2026ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2027ac46d4f3SJérôme Glisse ptl = pud_lock(vma->vm_mm, pud); 2028a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 2029a00cc7d9SMatthew Wilcox goto out; 2030ac46d4f3SJérôme Glisse __split_huge_pud_locked(vma, pud, range.start); 2031a00cc7d9SMatthew Wilcox 2032a00cc7d9SMatthew Wilcox out: 2033a00cc7d9SMatthew Wilcox spin_unlock(ptl); 20344645b9feSJérôme Glisse /* 20354645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 20364645b9feSJérôme Glisse * the above pudp_huge_clear_flush_notify() did already call it. 20374645b9feSJérôme Glisse */ 2038ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 2039a00cc7d9SMatthew Wilcox } 2040a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 2041a00cc7d9SMatthew Wilcox 2042eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2043eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2044eef1b3baSKirill A. Shutemov { 2045eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2046eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2047eef1b3baSKirill A. Shutemov pmd_t _pmd; 2048eef1b3baSKirill A. Shutemov int i; 2049eef1b3baSKirill A. Shutemov 20500f10851eSJérôme Glisse /* 20510f10851eSJérôme Glisse * Leave pmd empty until pte is filled note that it is fine to delay 20520f10851eSJérôme Glisse * notification until mmu_notifier_invalidate_range_end() as we are 20530f10851eSJérôme Glisse * replacing a zero pmd write protected page with a zero pte write 20540f10851eSJérôme Glisse * protected page. 20550f10851eSJérôme Glisse * 2056ee65728eSMike Rapoport * See Documentation/mm/mmu_notifier.rst 20570f10851eSJérôme Glisse */ 20580f10851eSJérôme Glisse pmdp_huge_clear_flush(vma, haddr, pmd); 2059eef1b3baSKirill A. Shutemov 2060eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2061eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2062eef1b3baSKirill A. Shutemov 2063eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 2064eef1b3baSKirill A. Shutemov pte_t *pte, entry; 2065eef1b3baSKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 2066eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 2067eef1b3baSKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 2068eef1b3baSKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 2069eef1b3baSKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 2070eef1b3baSKirill A. Shutemov pte_unmap(pte); 2071eef1b3baSKirill A. Shutemov } 2072eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2073eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2074eef1b3baSKirill A. Shutemov } 2075eef1b3baSKirill A. Shutemov 2076eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 2077ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 2078eef1b3baSKirill A. Shutemov { 2079eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2080eef1b3baSKirill A. Shutemov struct page *page; 2081eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2082423ac9afSAneesh Kumar K.V pmd_t old_pmd, _pmd; 2083292924b2SPeter Xu bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; 20840ccf7f16SPeter Xu bool anon_exclusive = false, dirty = false; 20852ac015e2SKirill A. Shutemov unsigned long addr; 2086eef1b3baSKirill A. Shutemov int i; 2087eef1b3baSKirill A. Shutemov 2088eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 2089eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2090eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 209184c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) 209284c3fc4eSZi Yan && !pmd_devmap(*pmd)); 2093eef1b3baSKirill A. Shutemov 2094eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 2095eef1b3baSKirill A. Shutemov 2096d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 209799fa8a48SHugh Dickins old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); 2098953c66c2SAneesh Kumar K.V /* 2099953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 2100953c66c2SAneesh Kumar K.V * just go ahead and zap it 2101953c66c2SAneesh Kumar K.V */ 2102953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 2103953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 21042484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) 2105d21b9e57SKirill A. Shutemov return; 210699fa8a48SHugh Dickins if (unlikely(is_pmd_migration_entry(old_pmd))) { 210799fa8a48SHugh Dickins swp_entry_t entry; 210899fa8a48SHugh Dickins 210999fa8a48SHugh Dickins entry = pmd_to_swp_entry(old_pmd); 2110af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 211199fa8a48SHugh Dickins } else { 211299fa8a48SHugh Dickins page = pmd_page(old_pmd); 211399fa8a48SHugh Dickins if (!PageDirty(page) && pmd_dirty(old_pmd)) 2114e1f1b157SHugh Dickins set_page_dirty(page); 211599fa8a48SHugh Dickins if (!PageReferenced(page) && pmd_young(old_pmd)) 2116d21b9e57SKirill A. Shutemov SetPageReferenced(page); 2117cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 2118d21b9e57SKirill A. Shutemov put_page(page); 211999fa8a48SHugh Dickins } 2120fadae295SYang Shi add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); 2121eef1b3baSKirill A. Shutemov return; 212299fa8a48SHugh Dickins } 212399fa8a48SHugh Dickins 21243b77e8c8SHugh Dickins if (is_huge_zero_pmd(*pmd)) { 21254645b9feSJérôme Glisse /* 21264645b9feSJérôme Glisse * FIXME: Do we want to invalidate secondary mmu by calling 21274645b9feSJérôme Glisse * mmu_notifier_invalidate_range() see comments below inside 21284645b9feSJérôme Glisse * __split_huge_pmd() ? 21294645b9feSJérôme Glisse * 21304645b9feSJérôme Glisse * We are going from a zero huge page write protected to zero 21314645b9feSJérôme Glisse * small page also write protected so it does not seems useful 21324645b9feSJérôme Glisse * to invalidate secondary mmu at this time. 21334645b9feSJérôme Glisse */ 2134eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 2135eef1b3baSKirill A. Shutemov } 2136eef1b3baSKirill A. Shutemov 2137423ac9afSAneesh Kumar K.V /* 2138423ac9afSAneesh Kumar K.V * Up to this point the pmd is present and huge and userland has the 2139423ac9afSAneesh Kumar K.V * whole access to the hugepage during the split (which happens in 2140423ac9afSAneesh Kumar K.V * place). If we overwrite the pmd with the not-huge version pointing 2141423ac9afSAneesh Kumar K.V * to the pte here (which of course we could if all CPUs were bug 2142423ac9afSAneesh Kumar K.V * free), userland could trigger a small page size TLB miss on the 2143423ac9afSAneesh Kumar K.V * small sized TLB while the hugepage TLB entry is still established in 2144423ac9afSAneesh Kumar K.V * the huge TLB. Some CPU doesn't like that. 214542742d9bSAlexander A. Klimov * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum 214642742d9bSAlexander A. Klimov * 383 on page 105. Intel should be safe but is also warns that it's 2147423ac9afSAneesh Kumar K.V * only safe if the permission and cache attributes of the two entries 2148423ac9afSAneesh Kumar K.V * loaded in the two TLB is identical (which should be the case here). 2149423ac9afSAneesh Kumar K.V * But it is generally safer to never allow small and huge TLB entries 2150423ac9afSAneesh Kumar K.V * for the same virtual address to be loaded simultaneously. So instead 2151423ac9afSAneesh Kumar K.V * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2152423ac9afSAneesh Kumar K.V * current pmd notpresent (atomically because here the pmd_trans_huge 2153423ac9afSAneesh Kumar K.V * must remain set at all times on the pmd until the split is complete 2154423ac9afSAneesh Kumar K.V * for this pmd), then we flush the SMP TLB and finally we write the 2155423ac9afSAneesh Kumar K.V * non-huge version of the pmd entry with pmd_populate. 2156423ac9afSAneesh Kumar K.V */ 2157423ac9afSAneesh Kumar K.V old_pmd = pmdp_invalidate(vma, haddr, pmd); 2158423ac9afSAneesh Kumar K.V 2159423ac9afSAneesh Kumar K.V pmd_migration = is_pmd_migration_entry(old_pmd); 21602e83ee1dSPeter Xu if (unlikely(pmd_migration)) { 216184c3fc4eSZi Yan swp_entry_t entry; 216284c3fc4eSZi Yan 2163423ac9afSAneesh Kumar K.V entry = pmd_to_swp_entry(old_pmd); 2164af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 21654dd845b5SAlistair Popple write = is_writable_migration_entry(entry); 21666c287605SDavid Hildenbrand if (PageAnon(page)) 21676c287605SDavid Hildenbrand anon_exclusive = is_readable_exclusive_migration_entry(entry); 21682e346877SPeter Xu young = is_migration_entry_young(entry); 21692e346877SPeter Xu dirty = is_migration_entry_dirty(entry); 21702e83ee1dSPeter Xu soft_dirty = pmd_swp_soft_dirty(old_pmd); 2171f45ec5ffSPeter Xu uffd_wp = pmd_swp_uffd_wp(old_pmd); 21722e83ee1dSPeter Xu } else { 2173423ac9afSAneesh Kumar K.V page = pmd_page(old_pmd); 21740ccf7f16SPeter Xu if (pmd_dirty(old_pmd)) { 21750ccf7f16SPeter Xu dirty = true; 2176423ac9afSAneesh Kumar K.V SetPageDirty(page); 21770ccf7f16SPeter Xu } 2178423ac9afSAneesh Kumar K.V write = pmd_write(old_pmd); 2179423ac9afSAneesh Kumar K.V young = pmd_young(old_pmd); 2180423ac9afSAneesh Kumar K.V soft_dirty = pmd_soft_dirty(old_pmd); 2181292924b2SPeter Xu uffd_wp = pmd_uffd_wp(old_pmd); 21826c287605SDavid Hildenbrand 21832e83ee1dSPeter Xu VM_BUG_ON_PAGE(!page_count(page), page); 21846c287605SDavid Hildenbrand 21856c287605SDavid Hildenbrand /* 21866c287605SDavid Hildenbrand * Without "freeze", we'll simply split the PMD, propagating the 21876c287605SDavid Hildenbrand * PageAnonExclusive() flag for each PTE by setting it for 21886c287605SDavid Hildenbrand * each subpage -- no need to (temporarily) clear. 21896c287605SDavid Hildenbrand * 21906c287605SDavid Hildenbrand * With "freeze" we want to replace mapped pages by 21916c287605SDavid Hildenbrand * migration entries right away. This is only possible if we 21926c287605SDavid Hildenbrand * managed to clear PageAnonExclusive() -- see 21936c287605SDavid Hildenbrand * set_pmd_migration_entry(). 21946c287605SDavid Hildenbrand * 21956c287605SDavid Hildenbrand * In case we cannot clear PageAnonExclusive(), split the PMD 21966c287605SDavid Hildenbrand * only and let try_to_migrate_one() fail later. 2197088b8aa5SDavid Hildenbrand * 2198088b8aa5SDavid Hildenbrand * See page_try_share_anon_rmap(): invalidate PMD first. 21996c287605SDavid Hildenbrand */ 22006c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 22016c287605SDavid Hildenbrand if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) 22026c287605SDavid Hildenbrand freeze = false; 220396d82debSHugh Dickins if (!freeze) 220496d82debSHugh Dickins page_ref_add(page, HPAGE_PMD_NR - 1); 22059d84604bSHugh Dickins } 2206eef1b3baSKirill A. Shutemov 2207423ac9afSAneesh Kumar K.V /* 2208423ac9afSAneesh Kumar K.V * Withdraw the table only after we mark the pmd entry invalid. 2209423ac9afSAneesh Kumar K.V * This's critical for some architectures (Power). 2210423ac9afSAneesh Kumar K.V */ 2211eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2212eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2213eef1b3baSKirill A. Shutemov 22142ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2215eef1b3baSKirill A. Shutemov pte_t entry, *pte; 2216eef1b3baSKirill A. Shutemov /* 2217eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 2218eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 2219eef1b3baSKirill A. Shutemov * permissions across VMAs. 2220eef1b3baSKirill A. Shutemov */ 222184c3fc4eSZi Yan if (freeze || pmd_migration) { 2222ba988280SKirill A. Shutemov swp_entry_t swp_entry; 22234dd845b5SAlistair Popple if (write) 22244dd845b5SAlistair Popple swp_entry = make_writable_migration_entry( 22254dd845b5SAlistair Popple page_to_pfn(page + i)); 22266c287605SDavid Hildenbrand else if (anon_exclusive) 22276c287605SDavid Hildenbrand swp_entry = make_readable_exclusive_migration_entry( 22286c287605SDavid Hildenbrand page_to_pfn(page + i)); 22294dd845b5SAlistair Popple else 22304dd845b5SAlistair Popple swp_entry = make_readable_migration_entry( 22314dd845b5SAlistair Popple page_to_pfn(page + i)); 22322e346877SPeter Xu if (young) 22332e346877SPeter Xu swp_entry = make_migration_entry_young(swp_entry); 22342e346877SPeter Xu if (dirty) 22352e346877SPeter Xu swp_entry = make_migration_entry_dirty(swp_entry); 2236ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 2237804dd150SAndrea Arcangeli if (soft_dirty) 2238804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 2239f45ec5ffSPeter Xu if (uffd_wp) 2240f45ec5ffSPeter Xu entry = pte_swp_mkuffd_wp(entry); 2241ba988280SKirill A. Shutemov } else { 22426d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 2243b8d3c4c3SMinchan Kim entry = maybe_mkwrite(entry, vma); 22446c287605SDavid Hildenbrand if (anon_exclusive) 22456c287605SDavid Hildenbrand SetPageAnonExclusive(page + i); 2246eef1b3baSKirill A. Shutemov if (!young) 2247eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 2248e833bc50SPeter Xu /* NOTE: this may set soft-dirty too on some archs */ 2249e833bc50SPeter Xu if (dirty) 2250e833bc50SPeter Xu entry = pte_mkdirty(entry); 2251624a2c94SPeter Xu /* 2252e833bc50SPeter Xu * NOTE: this needs to happen after pte_mkdirty, 2253e833bc50SPeter Xu * because some archs (sparc64, loongarch) could 2254e833bc50SPeter Xu * set hw write bit when mkdirty. 2255624a2c94SPeter Xu */ 2256e833bc50SPeter Xu if (!write) 2257e833bc50SPeter Xu entry = pte_wrprotect(entry); 2258804dd150SAndrea Arcangeli if (soft_dirty) 2259804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 2260292924b2SPeter Xu if (uffd_wp) 2261292924b2SPeter Xu entry = pte_mkuffd_wp(entry); 226296d82debSHugh Dickins page_add_anon_rmap(page + i, vma, addr, false); 2263ba988280SKirill A. Shutemov } 22642ac015e2SKirill A. Shutemov pte = pte_offset_map(&_pmd, addr); 2265eef1b3baSKirill A. Shutemov BUG_ON(!pte_none(*pte)); 22662ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 2267eef1b3baSKirill A. Shutemov pte_unmap(pte); 2268eef1b3baSKirill A. Shutemov } 2269eef1b3baSKirill A. Shutemov 2270cb67f428SHugh Dickins if (!pmd_migration) 2271cb67f428SHugh Dickins page_remove_rmap(page, vma, true); 227296d82debSHugh Dickins if (freeze) 227396d82debSHugh Dickins put_page(page); 2274eef1b3baSKirill A. Shutemov 2275eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2276eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2277eef1b3baSKirill A. Shutemov } 2278eef1b3baSKirill A. Shutemov 2279eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 2280af28a988SMatthew Wilcox (Oracle) unsigned long address, bool freeze, struct folio *folio) 2281eef1b3baSKirill A. Shutemov { 2282eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2283ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2284eef1b3baSKirill A. Shutemov 22857269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 22866f4f13e8SJérôme Glisse address & HPAGE_PMD_MASK, 2287ac46d4f3SJérôme Glisse (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); 2288ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2289ac46d4f3SJérôme Glisse ptl = pmd_lock(vma->vm_mm, pmd); 229033f4751eSNaoya Horiguchi 229133f4751eSNaoya Horiguchi /* 2292af28a988SMatthew Wilcox (Oracle) * If caller asks to setup a migration entry, we need a folio to check 2293af28a988SMatthew Wilcox (Oracle) * pmd against. Otherwise we can end up replacing wrong folio. 229433f4751eSNaoya Horiguchi */ 2295af28a988SMatthew Wilcox (Oracle) VM_BUG_ON(freeze && !folio); 229683a8441fSMatthew Wilcox (Oracle) VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); 229733f4751eSNaoya Horiguchi 22987f760917SDavid Hildenbrand if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || 229983a8441fSMatthew Wilcox (Oracle) is_pmd_migration_entry(*pmd)) { 2300cea33328SMiaohe Lin /* 2301cea33328SMiaohe Lin * It's safe to call pmd_page when folio is set because it's 2302cea33328SMiaohe Lin * guaranteed that pmd is present. 2303cea33328SMiaohe Lin */ 230483a8441fSMatthew Wilcox (Oracle) if (folio && folio != page_folio(pmd_page(*pmd))) 230583a8441fSMatthew Wilcox (Oracle) goto out; 2306ac46d4f3SJérôme Glisse __split_huge_pmd_locked(vma, pmd, range.start, freeze); 230783a8441fSMatthew Wilcox (Oracle) } 23087f760917SDavid Hildenbrand 2309e90309c9SKirill A. Shutemov out: 2310eef1b3baSKirill A. Shutemov spin_unlock(ptl); 23114645b9feSJérôme Glisse /* 23124645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback. 23134645b9feSJérôme Glisse * They are 3 cases to consider inside __split_huge_pmd_locked(): 23144645b9feSJérôme Glisse * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious 23154645b9feSJérôme Glisse * 2) __split_huge_zero_page_pmd() read only zero page and any write 23164645b9feSJérôme Glisse * fault will trigger a flush_notify before pointing to a new page 23174645b9feSJérôme Glisse * (it is fine if the secondary mmu keeps pointing to the old zero 23184645b9feSJérôme Glisse * page in the meantime) 23194645b9feSJérôme Glisse * 3) Split a huge pmd into pte pointing to the same page. No need 23204645b9feSJérôme Glisse * to invalidate secondary tlb entry they are all still valid. 23214645b9feSJérôme Glisse * any further changes to individual pte will notify. So no need 23224645b9feSJérôme Glisse * to call mmu_notifier->invalidate_range() 23234645b9feSJérôme Glisse */ 2324ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 2325eef1b3baSKirill A. Shutemov } 2326eef1b3baSKirill A. Shutemov 2327fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2328af28a988SMatthew Wilcox (Oracle) bool freeze, struct folio *folio) 232994fcc585SAndrea Arcangeli { 233050722804SZach O'Keefe pmd_t *pmd = mm_find_pmd(vma->vm_mm, address); 233194fcc585SAndrea Arcangeli 233250722804SZach O'Keefe if (!pmd) 2333f72e7dcdSHugh Dickins return; 2334f72e7dcdSHugh Dickins 2335af28a988SMatthew Wilcox (Oracle) __split_huge_pmd(vma, pmd, address, freeze, folio); 233694fcc585SAndrea Arcangeli } 233794fcc585SAndrea Arcangeli 233871f9e58eSMiaohe Lin static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) 233971f9e58eSMiaohe Lin { 234071f9e58eSMiaohe Lin /* 234171f9e58eSMiaohe Lin * If the new address isn't hpage aligned and it could previously 234271f9e58eSMiaohe Lin * contain an hugepage: check if we need to split an huge pmd. 234371f9e58eSMiaohe Lin */ 234471f9e58eSMiaohe Lin if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && 234571f9e58eSMiaohe Lin range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), 234671f9e58eSMiaohe Lin ALIGN(address, HPAGE_PMD_SIZE))) 234771f9e58eSMiaohe Lin split_huge_pmd_address(vma, address, false, NULL); 234871f9e58eSMiaohe Lin } 234971f9e58eSMiaohe Lin 2350e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 235194fcc585SAndrea Arcangeli unsigned long start, 235294fcc585SAndrea Arcangeli unsigned long end, 235394fcc585SAndrea Arcangeli long adjust_next) 235494fcc585SAndrea Arcangeli { 235571f9e58eSMiaohe Lin /* Check if we need to split start first. */ 235671f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, start); 235771f9e58eSMiaohe Lin 235871f9e58eSMiaohe Lin /* Check if we need to split end next. */ 235971f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, end); 236094fcc585SAndrea Arcangeli 236194fcc585SAndrea Arcangeli /* 236268540502SMatthew Wilcox (Oracle) * If we're also updating the next vma vm_start, 236371f9e58eSMiaohe Lin * check if we need to split it. 236494fcc585SAndrea Arcangeli */ 236594fcc585SAndrea Arcangeli if (adjust_next > 0) { 236668540502SMatthew Wilcox (Oracle) struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end); 236794fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 2368f9d86a60SWei Yang nstart += adjust_next; 236971f9e58eSMiaohe Lin split_huge_pmd_if_needed(next, nstart); 237094fcc585SAndrea Arcangeli } 237194fcc585SAndrea Arcangeli } 2372e9b61f19SKirill A. Shutemov 2373684555aaSMatthew Wilcox (Oracle) static void unmap_folio(struct folio *folio) 2374e9b61f19SKirill A. Shutemov { 2375a98a2f0cSAlistair Popple enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | 2376a98a2f0cSAlistair Popple TTU_SYNC; 2377e9b61f19SKirill A. Shutemov 2378684555aaSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2379e9b61f19SKirill A. Shutemov 2380a98a2f0cSAlistair Popple /* 2381a98a2f0cSAlistair Popple * Anon pages need migration entries to preserve them, but file 2382a98a2f0cSAlistair Popple * pages can simply be left unmapped, then faulted back on demand. 2383a98a2f0cSAlistair Popple * If that is ever changed (perhaps for mlock), update remap_page(). 2384a98a2f0cSAlistair Popple */ 23854b8554c5SMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 23864b8554c5SMatthew Wilcox (Oracle) try_to_migrate(folio, ttu_flags); 2387a98a2f0cSAlistair Popple else 2388869f7ee6SMatthew Wilcox (Oracle) try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); 2389bd56086fSKirill A. Shutemov } 2390bd56086fSKirill A. Shutemov 23914eecb8b9SMatthew Wilcox (Oracle) static void remap_page(struct folio *folio, unsigned long nr) 2392e9b61f19SKirill A. Shutemov { 23934eecb8b9SMatthew Wilcox (Oracle) int i = 0; 2394ab02c252SHugh Dickins 2395684555aaSMatthew Wilcox (Oracle) /* If unmap_folio() uses try_to_migrate() on file, remove this check */ 23964eecb8b9SMatthew Wilcox (Oracle) if (!folio_test_anon(folio)) 2397ab02c252SHugh Dickins return; 23984eecb8b9SMatthew Wilcox (Oracle) for (;;) { 23994eecb8b9SMatthew Wilcox (Oracle) remove_migration_ptes(folio, folio, true); 24004eecb8b9SMatthew Wilcox (Oracle) i += folio_nr_pages(folio); 24014eecb8b9SMatthew Wilcox (Oracle) if (i >= nr) 24024eecb8b9SMatthew Wilcox (Oracle) break; 24034eecb8b9SMatthew Wilcox (Oracle) folio = folio_next(folio); 2404e9b61f19SKirill A. Shutemov } 2405ace71a19SKirill A. Shutemov } 2406e9b61f19SKirill A. Shutemov 240794866635SAlex Shi static void lru_add_page_tail(struct page *head, struct page *tail, 240888dcb9a3SAlex Shi struct lruvec *lruvec, struct list_head *list) 240988dcb9a3SAlex Shi { 241094866635SAlex Shi VM_BUG_ON_PAGE(!PageHead(head), head); 241194866635SAlex Shi VM_BUG_ON_PAGE(PageCompound(tail), head); 241294866635SAlex Shi VM_BUG_ON_PAGE(PageLRU(tail), head); 24136168d0daSAlex Shi lockdep_assert_held(&lruvec->lru_lock); 241488dcb9a3SAlex Shi 24156dbb5741SAlex Shi if (list) { 241688dcb9a3SAlex Shi /* page reclaim is reclaiming a huge page */ 24176dbb5741SAlex Shi VM_WARN_ON(PageLRU(head)); 241894866635SAlex Shi get_page(tail); 241994866635SAlex Shi list_add_tail(&tail->lru, list); 242088dcb9a3SAlex Shi } else { 24216dbb5741SAlex Shi /* head is still on lru (and we have it frozen) */ 24226dbb5741SAlex Shi VM_WARN_ON(!PageLRU(head)); 242307ca7606SHugh Dickins if (PageUnevictable(tail)) 242407ca7606SHugh Dickins tail->mlock_count = 0; 242507ca7606SHugh Dickins else 24266dbb5741SAlex Shi list_add_tail(&tail->lru, &head->lru); 242707ca7606SHugh Dickins SetPageLRU(tail); 242888dcb9a3SAlex Shi } 242988dcb9a3SAlex Shi } 243088dcb9a3SAlex Shi 24318df651c7SKirill A. Shutemov static void __split_huge_page_tail(struct page *head, int tail, 2432e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2433e9b61f19SKirill A. Shutemov { 2434e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 2435e9b61f19SKirill A. Shutemov 24368df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2437e9b61f19SKirill A. Shutemov 2438e9b61f19SKirill A. Shutemov /* 2439605ca5edSKonstantin Khlebnikov * Clone page flags before unfreezing refcount. 2440605ca5edSKonstantin Khlebnikov * 2441605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow flags change, 24428958b249SHaitao Shi * for example lock_page() which set PG_waiters. 24436c287605SDavid Hildenbrand * 24446c287605SDavid Hildenbrand * Note that for mapped sub-pages of an anonymous THP, 2445684555aaSMatthew Wilcox (Oracle) * PG_anon_exclusive has been cleared in unmap_folio() and is stored in 24466c287605SDavid Hildenbrand * the migration entry instead from where remap_page() will restore it. 24476c287605SDavid Hildenbrand * We can still have PG_anon_exclusive set on effectively unmapped and 24486c287605SDavid Hildenbrand * unreferenced sub-pages of an anonymous THP: we can simply drop 24496c287605SDavid Hildenbrand * PG_anon_exclusive (-> PG_mappedtodisk) for these here. 2450e9b61f19SKirill A. Shutemov */ 2451e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2452e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2453e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2454e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 245538d8b4e6SHuang Ying (1L << PG_swapcache) | 2456e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2457e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2458e9b61f19SKirill A. Shutemov (1L << PG_active) | 24591899ad18SJohannes Weiner (1L << PG_workingset) | 2460e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2461b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 2462b0284cd2SCatalin Marinas #ifdef CONFIG_ARCH_USES_PG_ARCH_X 246372e6afa0SCatalin Marinas (1L << PG_arch_2) | 2464ef6458b1SPeter Collingbourne (1L << PG_arch_3) | 246572e6afa0SCatalin Marinas #endif 2466ec1c86b2SYu Zhao (1L << PG_dirty) | 2467ec1c86b2SYu Zhao LRU_GEN_MASK | LRU_REFS_MASK)); 2468e9b61f19SKirill A. Shutemov 2469cb67f428SHugh Dickins /* ->mapping in first and second tail page is replaced by other uses */ 2470173d9d9fSHugh Dickins VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2471173d9d9fSHugh Dickins page_tail); 2472173d9d9fSHugh Dickins page_tail->mapping = head->mapping; 2473173d9d9fSHugh Dickins page_tail->index = head->index + tail; 247471e2d666SMel Gorman 247571e2d666SMel Gorman /* 247671e2d666SMel Gorman * page->private should not be set in tail pages with the exception 247771e2d666SMel Gorman * of swap cache pages that store the swp_entry_t in tail pages. 247871e2d666SMel Gorman * Fix up and warn once if private is unexpectedly set. 2479cb67f428SHugh Dickins * 2480cb67f428SHugh Dickins * What of 32-bit systems, on which head[1].compound_pincount overlays 2481cb67f428SHugh Dickins * head[1].private? No problem: THP_SWAP is not enabled on 32-bit, and 2482cb67f428SHugh Dickins * compound_pincount must be 0 for folio_ref_freeze() to have succeeded. 248371e2d666SMel Gorman */ 248471e2d666SMel Gorman if (!folio_test_swapcache(page_folio(head))) { 24855aae9265SHugh Dickins VM_WARN_ON_ONCE_PAGE(page_tail->private != 0, page_tail); 2486b653db77SMatthew Wilcox (Oracle) page_tail->private = 0; 248771e2d666SMel Gorman } 2488173d9d9fSHugh Dickins 2489605ca5edSKonstantin Khlebnikov /* Page flags must be visible before we make the page non-compound. */ 2490e9b61f19SKirill A. Shutemov smp_wmb(); 2491e9b61f19SKirill A. Shutemov 2492605ca5edSKonstantin Khlebnikov /* 2493605ca5edSKonstantin Khlebnikov * Clear PageTail before unfreezing page refcount. 2494605ca5edSKonstantin Khlebnikov * 2495605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow put_page() 2496605ca5edSKonstantin Khlebnikov * which needs correct compound_head(). 2497605ca5edSKonstantin Khlebnikov */ 2498e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2499e9b61f19SKirill A. Shutemov 2500605ca5edSKonstantin Khlebnikov /* Finally unfreeze refcount. Additional reference from page cache. */ 2501605ca5edSKonstantin Khlebnikov page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || 2502605ca5edSKonstantin Khlebnikov PageSwapCache(head))); 2503605ca5edSKonstantin Khlebnikov 2504e9b61f19SKirill A. Shutemov if (page_is_young(head)) 2505e9b61f19SKirill A. Shutemov set_page_young(page_tail); 2506e9b61f19SKirill A. Shutemov if (page_is_idle(head)) 2507e9b61f19SKirill A. Shutemov set_page_idle(page_tail); 2508e9b61f19SKirill A. Shutemov 2509e9b61f19SKirill A. Shutemov page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); 251094723aafSMichal Hocko 251194723aafSMichal Hocko /* 251294723aafSMichal Hocko * always add to the tail because some iterators expect new 251394723aafSMichal Hocko * pages to show after the currently processed elements - e.g. 251494723aafSMichal Hocko * migrate_pages 251594723aafSMichal Hocko */ 2516e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2517e9b61f19SKirill A. Shutemov } 2518e9b61f19SKirill A. Shutemov 2519baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2520b6769834SAlex Shi pgoff_t end) 2521e9b61f19SKirill A. Shutemov { 2522e809c3feSMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2523e809c3feSMatthew Wilcox (Oracle) struct page *head = &folio->page; 2524e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 25254101196bSMatthew Wilcox (Oracle) struct address_space *swap_cache = NULL; 25264101196bSMatthew Wilcox (Oracle) unsigned long offset = 0; 25278cce5475SKirill A. Shutemov unsigned int nr = thp_nr_pages(head); 25288df651c7SKirill A. Shutemov int i; 2529e9b61f19SKirill A. Shutemov 2530e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2531be6c8982SZhou Guanghui split_page_memcg(head, nr); 2532e9b61f19SKirill A. Shutemov 25334101196bSMatthew Wilcox (Oracle) if (PageAnon(head) && PageSwapCache(head)) { 25344101196bSMatthew Wilcox (Oracle) swp_entry_t entry = { .val = page_private(head) }; 25354101196bSMatthew Wilcox (Oracle) 25364101196bSMatthew Wilcox (Oracle) offset = swp_offset(entry); 25374101196bSMatthew Wilcox (Oracle) swap_cache = swap_address_space(entry); 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--) { 25478df651c7SKirill A. Shutemov __split_huge_page_tail(head, 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)) 2553800d8c63SKirill A. Shutemov shmem_uncharge(head->mapping->host, 1); 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 25904eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, nr); 2591e9b61f19SKirill A. Shutemov 2592c4f9c701SHuang Ying if (PageSwapCache(head)) { 2593c4f9c701SHuang Ying swp_entry_t entry = { .val = page_private(head) }; 2594c4f9c701SHuang Ying 2595c4f9c701SHuang Ying split_swap_cluster(entry); 2596c4f9c701SHuang Ying } 2597c4f9c701SHuang Ying 25988cce5475SKirill A. Shutemov for (i = 0; i < nr; i++) { 2599e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2600e9b61f19SKirill A. Shutemov if (subpage == page) 2601e9b61f19SKirill A. Shutemov continue; 2602e9b61f19SKirill A. Shutemov unlock_page(subpage); 2603e9b61f19SKirill A. Shutemov 2604e9b61f19SKirill A. Shutemov /* 2605e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2606e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2607e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2608e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2609e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2610e9b61f19SKirill A. Shutemov */ 26110b175468SMiaohe Lin free_page_and_swap_cache(subpage); 2612e9b61f19SKirill A. Shutemov } 2613e9b61f19SKirill A. Shutemov } 2614e9b61f19SKirill A. Shutemov 2615b8f593cdSHuang Ying /* Racy check whether the huge page can be split */ 2616d4b4084aSMatthew Wilcox (Oracle) bool can_split_folio(struct folio *folio, int *pextra_pins) 2617b8f593cdSHuang Ying { 2618b8f593cdSHuang Ying int extra_pins; 2619b8f593cdSHuang Ying 2620aa5dc07fSMatthew Wilcox /* Additional pins from page cache */ 2621d4b4084aSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 2622d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_test_swapcache(folio) ? 2623d4b4084aSMatthew Wilcox (Oracle) folio_nr_pages(folio) : 0; 2624b8f593cdSHuang Ying else 2625d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_nr_pages(folio); 2626b8f593cdSHuang Ying if (pextra_pins) 2627b8f593cdSHuang Ying *pextra_pins = extra_pins; 2628d4b4084aSMatthew Wilcox (Oracle) return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; 2629b8f593cdSHuang Ying } 2630b8f593cdSHuang Ying 26316d0a07edSAndrea Arcangeli /* 2632e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2633e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2634e9b61f19SKirill A. Shutemov * 2635e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2636e9b61f19SKirill A. Shutemov * The huge page must be locked. 2637e9b61f19SKirill A. Shutemov * 2638e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2639e9b61f19SKirill A. Shutemov * 2640e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2641e9b61f19SKirill A. Shutemov * the hugepage. 2642e9b61f19SKirill A. Shutemov * 2643e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2644e9b61f19SKirill A. Shutemov * they are not mapped. 2645e9b61f19SKirill A. Shutemov * 2646e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2647e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2648e9b61f19SKirill A. Shutemov * us. 2649e9b61f19SKirill A. Shutemov */ 2650e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2651e9b61f19SKirill A. Shutemov { 26524eecb8b9SMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 26533e9a13daSMatthew Wilcox (Oracle) struct deferred_split *ds_queue = get_deferred_split_queue(&folio->page); 26543e9a13daSMatthew Wilcox (Oracle) XA_STATE(xas, &folio->mapping->i_pages, folio->index); 2655baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2656baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2657504e070dSYang Shi int extra_pins, ret; 2658006d3ff2SHugh Dickins pgoff_t end; 2659478d134eSXu Yu bool is_hzp; 2660e9b61f19SKirill A. Shutemov 26613e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); 26623e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2663e9b61f19SKirill A. Shutemov 26643e9a13daSMatthew Wilcox (Oracle) is_hzp = is_huge_zero_page(&folio->page); 26653e9a13daSMatthew Wilcox (Oracle) VM_WARN_ON_ONCE_FOLIO(is_hzp, folio); 2666478d134eSXu Yu if (is_hzp) 2667478d134eSXu Yu return -EBUSY; 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 27036a3edd29SYin Fengwei if (folio_test_private(folio) && 27046a3edd29SYin Fengwei !filemap_release_folio(folio, gfp)) { 27056a3edd29SYin Fengwei ret = -EBUSY; 27066a3edd29SYin Fengwei goto out; 27076a3edd29SYin Fengwei } 27086a3edd29SYin Fengwei 27093e9a13daSMatthew Wilcox (Oracle) xas_split_alloc(&xas, folio, folio_order(folio), gfp); 27106b24ca4aSMatthew Wilcox (Oracle) if (xas_error(&xas)) { 27116b24ca4aSMatthew Wilcox (Oracle) ret = xas_error(&xas); 27126b24ca4aSMatthew Wilcox (Oracle) goto out; 27136b24ca4aSMatthew Wilcox (Oracle) } 27146b24ca4aSMatthew Wilcox (Oracle) 2715baa355fdSKirill A. Shutemov anon_vma = NULL; 2716baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 2717006d3ff2SHugh Dickins 2718006d3ff2SHugh Dickins /* 2719006d3ff2SHugh Dickins *__split_huge_page() may need to trim off pages beyond EOF: 2720006d3ff2SHugh Dickins * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, 2721006d3ff2SHugh Dickins * which cannot be nested inside the page tree lock. So note 2722006d3ff2SHugh Dickins * end now: i_size itself may be changed at any moment, but 27233e9a13daSMatthew Wilcox (Oracle) * folio lock is good enough to serialize the trimming. 2724006d3ff2SHugh Dickins */ 2725006d3ff2SHugh Dickins end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); 2726d144bf62SHugh Dickins if (shmem_mapping(mapping)) 2727d144bf62SHugh Dickins end = shmem_fallocend(mapping->host, end); 2728baa355fdSKirill A. Shutemov } 2729e9b61f19SKirill A. Shutemov 2730e9b61f19SKirill A. Shutemov /* 2731684555aaSMatthew Wilcox (Oracle) * Racy check if we can split the page, before unmap_folio() will 2732e9b61f19SKirill A. Shutemov * split PMDs 2733e9b61f19SKirill A. Shutemov */ 2734d4b4084aSMatthew Wilcox (Oracle) if (!can_split_folio(folio, &extra_pins)) { 2735fd4a7ac3SBaolin Wang ret = -EAGAIN; 2736e9b61f19SKirill A. Shutemov goto out_unlock; 2737e9b61f19SKirill A. Shutemov } 2738e9b61f19SKirill A. Shutemov 2739684555aaSMatthew Wilcox (Oracle) unmap_folio(folio); 2740e9b61f19SKirill A. Shutemov 2741b6769834SAlex Shi /* block interrupt reentry in xa_lock and spinlock */ 2742b6769834SAlex Shi local_irq_disable(); 2743baa355fdSKirill A. Shutemov if (mapping) { 2744baa355fdSKirill A. Shutemov /* 27453e9a13daSMatthew Wilcox (Oracle) * Check if the folio is present in page cache. 27463e9a13daSMatthew Wilcox (Oracle) * We assume all tail are present too, if folio is there. 2747baa355fdSKirill A. Shutemov */ 27486b24ca4aSMatthew Wilcox (Oracle) xas_lock(&xas); 27496b24ca4aSMatthew Wilcox (Oracle) xas_reset(&xas); 27503e9a13daSMatthew Wilcox (Oracle) if (xas_load(&xas) != folio) 2751baa355fdSKirill A. Shutemov goto fail; 2752baa355fdSKirill A. Shutemov } 2753baa355fdSKirill A. Shutemov 27540139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 2755364c1eebSYang Shi spin_lock(&ds_queue->split_queue_lock); 27563e9a13daSMatthew Wilcox (Oracle) if (folio_ref_freeze(folio, 1 + extra_pins)) { 27573e9a13daSMatthew Wilcox (Oracle) if (!list_empty(page_deferred_list(&folio->page))) { 2758364c1eebSYang Shi ds_queue->split_queue_len--; 27593e9a13daSMatthew Wilcox (Oracle) list_del(page_deferred_list(&folio->page)); 27609a982250SKirill A. Shutemov } 2761afb97172SWei Yang spin_unlock(&ds_queue->split_queue_lock); 276206d3eff6SKirill A. Shutemov if (mapping) { 27633e9a13daSMatthew Wilcox (Oracle) int nr = folio_nr_pages(folio); 2764bf9eceadSMuchun Song 27653e9a13daSMatthew Wilcox (Oracle) xas_split(&xas, folio, folio_order(folio)); 27663e9a13daSMatthew Wilcox (Oracle) if (folio_test_swapbacked(folio)) { 27673e9a13daSMatthew Wilcox (Oracle) __lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, 276857b2847dSMuchun Song -nr); 27691ca7554dSMarek Szyprowski } else { 27703e9a13daSMatthew Wilcox (Oracle) __lruvec_stat_mod_folio(folio, NR_FILE_THPS, 2771bf9eceadSMuchun Song -nr); 27721ca7554dSMarek Szyprowski filemap_nr_thps_dec(mapping); 27731ca7554dSMarek Szyprowski } 277406d3eff6SKirill A. Shutemov } 277506d3eff6SKirill A. Shutemov 2776b6769834SAlex Shi __split_huge_page(page, list, end); 2777e9b61f19SKirill A. Shutemov ret = 0; 2778baa355fdSKirill A. Shutemov } else { 2779364c1eebSYang Shi spin_unlock(&ds_queue->split_queue_lock); 2780504e070dSYang Shi fail: 2781504e070dSYang Shi if (mapping) 27826b24ca4aSMatthew Wilcox (Oracle) xas_unlock(&xas); 2783b6769834SAlex Shi local_irq_enable(); 27844eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, folio_nr_pages(folio)); 2785fd4a7ac3SBaolin Wang ret = -EAGAIN; 2786e9b61f19SKirill A. Shutemov } 2787e9b61f19SKirill A. Shutemov 2788e9b61f19SKirill A. Shutemov out_unlock: 2789baa355fdSKirill A. Shutemov if (anon_vma) { 2790e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 2791e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 2792baa355fdSKirill A. Shutemov } 2793baa355fdSKirill A. Shutemov if (mapping) 2794baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 2795e9b61f19SKirill A. Shutemov out: 279669a37a8bSMatthew Wilcox (Oracle) xas_destroy(&xas); 2797e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 2798e9b61f19SKirill A. Shutemov return ret; 2799e9b61f19SKirill A. Shutemov } 28009a982250SKirill A. Shutemov 28019a982250SKirill A. Shutemov void free_transhuge_page(struct page *page) 28029a982250SKirill A. Shutemov { 280387eaceb3SYang Shi struct deferred_split *ds_queue = get_deferred_split_queue(page); 28049a982250SKirill A. Shutemov unsigned long flags; 28059a982250SKirill A. Shutemov 2806364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28079a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(page))) { 2808364c1eebSYang Shi ds_queue->split_queue_len--; 28099a982250SKirill A. Shutemov list_del(page_deferred_list(page)); 28109a982250SKirill A. Shutemov } 2811364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28129a982250SKirill A. Shutemov free_compound_page(page); 28139a982250SKirill A. Shutemov } 28149a982250SKirill A. Shutemov 28159a982250SKirill A. Shutemov void deferred_split_huge_page(struct page *page) 28169a982250SKirill A. Shutemov { 281787eaceb3SYang Shi struct deferred_split *ds_queue = get_deferred_split_queue(page); 281887eaceb3SYang Shi #ifdef CONFIG_MEMCG 2819bcfe06bfSRoman Gushchin struct mem_cgroup *memcg = page_memcg(compound_head(page)); 282087eaceb3SYang Shi #endif 28219a982250SKirill A. Shutemov unsigned long flags; 28229a982250SKirill A. Shutemov 28239a982250SKirill A. Shutemov VM_BUG_ON_PAGE(!PageTransHuge(page), page); 28249a982250SKirill A. Shutemov 282587eaceb3SYang Shi /* 282687eaceb3SYang Shi * The try_to_unmap() in page reclaim path might reach here too, 282787eaceb3SYang Shi * this may cause a race condition to corrupt deferred split queue. 282887eaceb3SYang Shi * And, if page reclaim is already handling the same page, it is 282987eaceb3SYang Shi * unnecessary to handle it again in shrinker. 283087eaceb3SYang Shi * 283187eaceb3SYang Shi * Check PageSwapCache to determine if the page is being 283287eaceb3SYang Shi * handled by page reclaim since THP swap would add the page into 283387eaceb3SYang Shi * swap cache before calling try_to_unmap(). 283487eaceb3SYang Shi */ 283587eaceb3SYang Shi if (PageSwapCache(page)) 283687eaceb3SYang Shi return; 283787eaceb3SYang Shi 2838364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28399a982250SKirill A. Shutemov if (list_empty(page_deferred_list(page))) { 2840f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 2841364c1eebSYang Shi list_add_tail(page_deferred_list(page), &ds_queue->split_queue); 2842364c1eebSYang Shi ds_queue->split_queue_len++; 284387eaceb3SYang Shi #ifdef CONFIG_MEMCG 284487eaceb3SYang Shi if (memcg) 28452bfd3637SYang Shi set_shrinker_bit(memcg, page_to_nid(page), 284687eaceb3SYang Shi deferred_split_shrinker.id); 284787eaceb3SYang Shi #endif 28489a982250SKirill A. Shutemov } 2849364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28509a982250SKirill A. Shutemov } 28519a982250SKirill A. Shutemov 28529a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 28539a982250SKirill A. Shutemov struct shrink_control *sc) 28549a982250SKirill A. Shutemov { 2855a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2856364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 285787eaceb3SYang Shi 285887eaceb3SYang Shi #ifdef CONFIG_MEMCG 285987eaceb3SYang Shi if (sc->memcg) 286087eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 286187eaceb3SYang Shi #endif 2862364c1eebSYang Shi return READ_ONCE(ds_queue->split_queue_len); 28639a982250SKirill A. Shutemov } 28649a982250SKirill A. Shutemov 28659a982250SKirill A. Shutemov static unsigned long deferred_split_scan(struct shrinker *shrink, 28669a982250SKirill A. Shutemov struct shrink_control *sc) 28679a982250SKirill A. Shutemov { 2868a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2869364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 28709a982250SKirill A. Shutemov unsigned long flags; 28719a982250SKirill A. Shutemov LIST_HEAD(list), *pos, *next; 28729a982250SKirill A. Shutemov struct page *page; 28739a982250SKirill A. Shutemov int split = 0; 28749a982250SKirill A. Shutemov 287587eaceb3SYang Shi #ifdef CONFIG_MEMCG 287687eaceb3SYang Shi if (sc->memcg) 287787eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 287887eaceb3SYang Shi #endif 287987eaceb3SYang Shi 2880364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28819a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 2882364c1eebSYang Shi list_for_each_safe(pos, next, &ds_queue->split_queue) { 2883dfe5c51cSMiaohe Lin page = list_entry((void *)pos, struct page, deferred_list); 28849a982250SKirill A. Shutemov page = compound_head(page); 2885e3ae1953SKirill A. Shutemov if (get_page_unless_zero(page)) { 2886e3ae1953SKirill A. Shutemov list_move(page_deferred_list(page), &list); 2887e3ae1953SKirill A. Shutemov } else { 2888e3ae1953SKirill A. Shutemov /* We lost race with put_compound_page() */ 28899a982250SKirill A. Shutemov list_del_init(page_deferred_list(page)); 2890364c1eebSYang Shi ds_queue->split_queue_len--; 28919a982250SKirill A. Shutemov } 2892e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 2893e3ae1953SKirill A. Shutemov break; 28949a982250SKirill A. Shutemov } 2895364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28969a982250SKirill A. Shutemov 28979a982250SKirill A. Shutemov list_for_each_safe(pos, next, &list) { 2898dfe5c51cSMiaohe Lin page = list_entry((void *)pos, struct page, deferred_list); 2899fa41b900SKirill A. Shutemov if (!trylock_page(page)) 2900fa41b900SKirill A. Shutemov goto next; 29019a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 29029a982250SKirill A. Shutemov if (!split_huge_page(page)) 29039a982250SKirill A. Shutemov split++; 29049a982250SKirill A. Shutemov unlock_page(page); 2905fa41b900SKirill A. Shutemov next: 29069a982250SKirill A. Shutemov put_page(page); 29079a982250SKirill A. Shutemov } 29089a982250SKirill A. Shutemov 2909364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 2910364c1eebSYang Shi list_splice_tail(&list, &ds_queue->split_queue); 2911364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 29129a982250SKirill A. Shutemov 2913cb8d68ecSKirill A. Shutemov /* 2914cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 2915cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 2916cb8d68ecSKirill A. Shutemov */ 2917364c1eebSYang Shi if (!split && list_empty(&ds_queue->split_queue)) 2918cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 2919cb8d68ecSKirill A. Shutemov return split; 29209a982250SKirill A. Shutemov } 29219a982250SKirill A. Shutemov 29229a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker = { 29239a982250SKirill A. Shutemov .count_objects = deferred_split_count, 29249a982250SKirill A. Shutemov .scan_objects = deferred_split_scan, 29259a982250SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 292687eaceb3SYang Shi .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | 292787eaceb3SYang Shi SHRINKER_NONSLAB, 29289a982250SKirill A. Shutemov }; 292949071d43SKirill 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; 293549071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 293649071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 293749071d43SKirill A. Shutemov 2938fa6c0231SZi Yan pr_debug("Split all THPs\n"); 2939a17206daSMiaohe Lin for_each_zone(zone) { 2940a17206daSMiaohe Lin if (!managed_zone(zone)) 2941a17206daSMiaohe Lin continue; 294249071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 294349071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 2944a17206daSMiaohe Lin int nr_pages; 294549071d43SKirill A. Shutemov 29462b7aa91bSNaoya Horiguchi page = pfn_to_online_page(pfn); 29472b7aa91bSNaoya Horiguchi if (!page || !get_page_unless_zero(page)) 294849071d43SKirill A. Shutemov continue; 294949071d43SKirill A. Shutemov 295049071d43SKirill A. Shutemov if (zone != page_zone(page)) 295149071d43SKirill A. Shutemov goto next; 295249071d43SKirill A. Shutemov 2953baa355fdSKirill A. Shutemov if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) 295449071d43SKirill A. Shutemov goto next; 295549071d43SKirill A. Shutemov 295649071d43SKirill A. Shutemov total++; 295749071d43SKirill A. Shutemov lock_page(page); 2958a17206daSMiaohe Lin nr_pages = thp_nr_pages(page); 295949071d43SKirill A. Shutemov if (!split_huge_page(page)) 296049071d43SKirill A. Shutemov split++; 2961a17206daSMiaohe Lin pfn += nr_pages - 1; 296249071d43SKirill A. Shutemov unlock_page(page); 296349071d43SKirill A. Shutemov next: 296449071d43SKirill A. Shutemov put_page(page); 2965fa6c0231SZi Yan cond_resched(); 296649071d43SKirill A. Shutemov } 296749071d43SKirill A. Shutemov } 296849071d43SKirill A. Shutemov 2969fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 297049071d43SKirill A. Shutemov } 2971fa6c0231SZi Yan 2972fa6c0231SZi Yan static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) 2973fa6c0231SZi Yan { 2974fa6c0231SZi Yan return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || 2975fa6c0231SZi Yan is_vm_hugetlb_page(vma); 2976fa6c0231SZi Yan } 2977fa6c0231SZi Yan 2978fa6c0231SZi Yan static int split_huge_pages_pid(int pid, unsigned long vaddr_start, 2979fa6c0231SZi Yan unsigned long vaddr_end) 2980fa6c0231SZi Yan { 2981fa6c0231SZi Yan int ret = 0; 2982fa6c0231SZi Yan struct task_struct *task; 2983fa6c0231SZi Yan struct mm_struct *mm; 2984fa6c0231SZi Yan unsigned long total = 0, split = 0; 2985fa6c0231SZi Yan unsigned long addr; 2986fa6c0231SZi Yan 2987fa6c0231SZi Yan vaddr_start &= PAGE_MASK; 2988fa6c0231SZi Yan vaddr_end &= PAGE_MASK; 2989fa6c0231SZi Yan 2990fa6c0231SZi Yan /* Find the task_struct from pid */ 2991fa6c0231SZi Yan rcu_read_lock(); 2992fa6c0231SZi Yan task = find_task_by_vpid(pid); 2993fa6c0231SZi Yan if (!task) { 2994fa6c0231SZi Yan rcu_read_unlock(); 2995fa6c0231SZi Yan ret = -ESRCH; 2996fa6c0231SZi Yan goto out; 2997fa6c0231SZi Yan } 2998fa6c0231SZi Yan get_task_struct(task); 2999fa6c0231SZi Yan rcu_read_unlock(); 3000fa6c0231SZi Yan 3001fa6c0231SZi Yan /* Find the mm_struct */ 3002fa6c0231SZi Yan mm = get_task_mm(task); 3003fa6c0231SZi Yan put_task_struct(task); 3004fa6c0231SZi Yan 3005fa6c0231SZi Yan if (!mm) { 3006fa6c0231SZi Yan ret = -EINVAL; 3007fa6c0231SZi Yan goto out; 3008fa6c0231SZi Yan } 3009fa6c0231SZi Yan 3010fa6c0231SZi Yan pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", 3011fa6c0231SZi Yan pid, vaddr_start, vaddr_end); 3012fa6c0231SZi Yan 3013fa6c0231SZi Yan mmap_read_lock(mm); 3014fa6c0231SZi Yan /* 3015fa6c0231SZi Yan * always increase addr by PAGE_SIZE, since we could have a PTE page 3016fa6c0231SZi Yan * table filled with PTE-mapped THPs, each of which is distinct. 3017fa6c0231SZi Yan */ 3018fa6c0231SZi Yan for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { 301974ba2b38SMiaohe Lin struct vm_area_struct *vma = vma_lookup(mm, addr); 3020fa6c0231SZi Yan struct page *page; 3021fa6c0231SZi Yan 302274ba2b38SMiaohe Lin if (!vma) 3023fa6c0231SZi Yan break; 3024fa6c0231SZi Yan 3025fa6c0231SZi Yan /* skip special VMA and hugetlb VMA */ 3026fa6c0231SZi Yan if (vma_not_suitable_for_thp_split(vma)) { 3027fa6c0231SZi Yan addr = vma->vm_end; 3028fa6c0231SZi Yan continue; 3029fa6c0231SZi Yan } 3030fa6c0231SZi Yan 3031fa6c0231SZi Yan /* FOLL_DUMP to ignore special (like zero) pages */ 303287d2762eSMiaohe Lin page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); 3033fa6c0231SZi Yan 3034f7091ed6SHaiyue Wang if (IS_ERR_OR_NULL(page)) 3035fa6c0231SZi Yan continue; 3036fa6c0231SZi Yan 3037fa6c0231SZi Yan if (!is_transparent_hugepage(page)) 3038fa6c0231SZi Yan goto next; 3039fa6c0231SZi Yan 3040fa6c0231SZi Yan total++; 3041d4b4084aSMatthew Wilcox (Oracle) if (!can_split_folio(page_folio(page), NULL)) 3042fa6c0231SZi Yan goto next; 3043fa6c0231SZi Yan 3044fa6c0231SZi Yan if (!trylock_page(page)) 3045fa6c0231SZi Yan goto next; 3046fa6c0231SZi Yan 3047fa6c0231SZi Yan if (!split_huge_page(page)) 3048fa6c0231SZi Yan split++; 3049fa6c0231SZi Yan 3050fa6c0231SZi Yan unlock_page(page); 3051fa6c0231SZi Yan next: 3052fa6c0231SZi Yan put_page(page); 3053fa6c0231SZi Yan cond_resched(); 3054fa6c0231SZi Yan } 3055fa6c0231SZi Yan mmap_read_unlock(mm); 3056fa6c0231SZi Yan mmput(mm); 3057fa6c0231SZi Yan 3058fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 3059fa6c0231SZi Yan 3060fa6c0231SZi Yan out: 3061fa6c0231SZi Yan return ret; 3062fa6c0231SZi Yan } 3063fa6c0231SZi Yan 3064fbe37501SZi Yan static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, 3065fbe37501SZi Yan pgoff_t off_end) 3066fbe37501SZi Yan { 3067fbe37501SZi Yan struct filename *file; 3068fbe37501SZi Yan struct file *candidate; 3069fbe37501SZi Yan struct address_space *mapping; 3070fbe37501SZi Yan int ret = -EINVAL; 3071fbe37501SZi Yan pgoff_t index; 3072fbe37501SZi Yan int nr_pages = 1; 3073fbe37501SZi Yan unsigned long total = 0, split = 0; 3074fbe37501SZi Yan 3075fbe37501SZi Yan file = getname_kernel(file_path); 3076fbe37501SZi Yan if (IS_ERR(file)) 3077fbe37501SZi Yan return ret; 3078fbe37501SZi Yan 3079fbe37501SZi Yan candidate = file_open_name(file, O_RDONLY, 0); 3080fbe37501SZi Yan if (IS_ERR(candidate)) 3081fbe37501SZi Yan goto out; 3082fbe37501SZi Yan 3083fbe37501SZi Yan pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", 3084fbe37501SZi Yan file_path, off_start, off_end); 3085fbe37501SZi Yan 3086fbe37501SZi Yan mapping = candidate->f_mapping; 3087fbe37501SZi Yan 3088fbe37501SZi Yan for (index = off_start; index < off_end; index += nr_pages) { 30899ee2c086SMatthew Wilcox (Oracle) struct folio *folio = __filemap_get_folio(mapping, index, 30909ee2c086SMatthew Wilcox (Oracle) FGP_ENTRY, 0); 3091fbe37501SZi Yan 3092fbe37501SZi Yan nr_pages = 1; 30939ee2c086SMatthew Wilcox (Oracle) if (xa_is_value(folio) || !folio) 3094fbe37501SZi Yan continue; 3095fbe37501SZi Yan 30969ee2c086SMatthew Wilcox (Oracle) if (!folio_test_large(folio)) 3097fbe37501SZi Yan goto next; 3098fbe37501SZi Yan 3099fbe37501SZi Yan total++; 31009ee2c086SMatthew Wilcox (Oracle) nr_pages = folio_nr_pages(folio); 3101fbe37501SZi Yan 31029ee2c086SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 3103fbe37501SZi Yan goto next; 3104fbe37501SZi Yan 31059ee2c086SMatthew Wilcox (Oracle) if (!split_folio(folio)) 3106fbe37501SZi Yan split++; 3107fbe37501SZi Yan 31089ee2c086SMatthew Wilcox (Oracle) folio_unlock(folio); 3109fbe37501SZi Yan next: 31109ee2c086SMatthew Wilcox (Oracle) folio_put(folio); 3111fbe37501SZi Yan cond_resched(); 3112fbe37501SZi Yan } 3113fbe37501SZi Yan 3114fbe37501SZi Yan filp_close(candidate, NULL); 3115fbe37501SZi Yan ret = 0; 3116fbe37501SZi Yan 3117fbe37501SZi Yan pr_debug("%lu of %lu file-backed THP split\n", split, total); 3118fbe37501SZi Yan out: 3119fbe37501SZi Yan putname(file); 3120fbe37501SZi Yan return ret; 3121fbe37501SZi Yan } 3122fbe37501SZi Yan 3123fa6c0231SZi Yan #define MAX_INPUT_BUF_SZ 255 3124fa6c0231SZi Yan 3125fa6c0231SZi Yan static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, 3126fa6c0231SZi Yan size_t count, loff_t *ppops) 3127fa6c0231SZi Yan { 3128fa6c0231SZi Yan static DEFINE_MUTEX(split_debug_mutex); 3129fa6c0231SZi Yan ssize_t ret; 3130fbe37501SZi Yan /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ 3131fbe37501SZi Yan char input_buf[MAX_INPUT_BUF_SZ]; 3132fa6c0231SZi Yan int pid; 3133fa6c0231SZi Yan unsigned long vaddr_start, vaddr_end; 3134fa6c0231SZi Yan 3135fa6c0231SZi Yan ret = mutex_lock_interruptible(&split_debug_mutex); 3136fa6c0231SZi Yan if (ret) 3137fa6c0231SZi Yan return ret; 3138fa6c0231SZi Yan 3139fa6c0231SZi Yan ret = -EFAULT; 3140fa6c0231SZi Yan 3141fa6c0231SZi Yan memset(input_buf, 0, MAX_INPUT_BUF_SZ); 3142fa6c0231SZi Yan if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) 3143fa6c0231SZi Yan goto out; 3144fa6c0231SZi Yan 3145fa6c0231SZi Yan input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; 3146fbe37501SZi Yan 3147fbe37501SZi Yan if (input_buf[0] == '/') { 3148fbe37501SZi Yan char *tok; 3149fbe37501SZi Yan char *buf = input_buf; 3150fbe37501SZi Yan char file_path[MAX_INPUT_BUF_SZ]; 3151fbe37501SZi Yan pgoff_t off_start = 0, off_end = 0; 3152fbe37501SZi Yan size_t input_len = strlen(input_buf); 3153fbe37501SZi Yan 3154fbe37501SZi Yan tok = strsep(&buf, ","); 3155fbe37501SZi Yan if (tok) { 31561212e00cSMatthew Wilcox (Oracle) strcpy(file_path, tok); 3157fbe37501SZi Yan } else { 3158fbe37501SZi Yan ret = -EINVAL; 3159fbe37501SZi Yan goto out; 3160fbe37501SZi Yan } 3161fbe37501SZi Yan 3162fbe37501SZi Yan ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); 3163fbe37501SZi Yan if (ret != 2) { 3164fbe37501SZi Yan ret = -EINVAL; 3165fbe37501SZi Yan goto out; 3166fbe37501SZi Yan } 3167fbe37501SZi Yan ret = split_huge_pages_in_file(file_path, off_start, off_end); 3168fbe37501SZi Yan if (!ret) 3169fbe37501SZi Yan ret = input_len; 3170fbe37501SZi Yan 3171fbe37501SZi Yan goto out; 3172fbe37501SZi Yan } 3173fbe37501SZi Yan 3174fa6c0231SZi Yan ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); 3175fa6c0231SZi Yan if (ret == 1 && pid == 1) { 3176fa6c0231SZi Yan split_huge_pages_all(); 3177fa6c0231SZi Yan ret = strlen(input_buf); 3178fa6c0231SZi Yan goto out; 3179fa6c0231SZi Yan } else if (ret != 3) { 3180fa6c0231SZi Yan ret = -EINVAL; 3181fa6c0231SZi Yan goto out; 3182fa6c0231SZi Yan } 3183fa6c0231SZi Yan 3184fa6c0231SZi Yan ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); 3185fa6c0231SZi Yan if (!ret) 3186fa6c0231SZi Yan ret = strlen(input_buf); 3187fa6c0231SZi Yan out: 3188fa6c0231SZi Yan mutex_unlock(&split_debug_mutex); 3189fa6c0231SZi Yan return ret; 3190fa6c0231SZi Yan 3191fa6c0231SZi Yan } 3192fa6c0231SZi Yan 3193fa6c0231SZi Yan static const struct file_operations split_huge_pages_fops = { 3194fa6c0231SZi Yan .owner = THIS_MODULE, 3195fa6c0231SZi Yan .write = split_huge_pages_write, 3196fa6c0231SZi Yan .llseek = no_llseek, 3197fa6c0231SZi Yan }; 319849071d43SKirill A. Shutemov 319949071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 320049071d43SKirill A. Shutemov { 3201d9f7979cSGreg Kroah-Hartman debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 320249071d43SKirill A. Shutemov &split_huge_pages_fops); 320349071d43SKirill A. Shutemov return 0; 320449071d43SKirill A. Shutemov } 320549071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 320649071d43SKirill A. Shutemov #endif 3207616b8371SZi Yan 3208616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 32097f5abe60SDavid Hildenbrand int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 3210616b8371SZi Yan struct page *page) 3211616b8371SZi Yan { 3212616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3213616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3214616b8371SZi Yan unsigned long address = pvmw->address; 32156c287605SDavid Hildenbrand bool anon_exclusive; 3216616b8371SZi Yan pmd_t pmdval; 3217616b8371SZi Yan swp_entry_t entry; 3218ab6e3d09SNaoya Horiguchi pmd_t pmdswp; 3219616b8371SZi Yan 3220616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 32217f5abe60SDavid Hildenbrand return 0; 3222616b8371SZi Yan 3223616b8371SZi Yan flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); 32248a8683adSHuang Ying pmdval = pmdp_invalidate(vma, address, pvmw->pmd); 32256c287605SDavid Hildenbrand 3226088b8aa5SDavid Hildenbrand /* See page_try_share_anon_rmap(): invalidate PMD first. */ 32276c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 32286c287605SDavid Hildenbrand if (anon_exclusive && page_try_share_anon_rmap(page)) { 32296c287605SDavid Hildenbrand set_pmd_at(mm, address, pvmw->pmd, pmdval); 32307f5abe60SDavid Hildenbrand return -EBUSY; 32316c287605SDavid Hildenbrand } 32326c287605SDavid Hildenbrand 3233616b8371SZi Yan if (pmd_dirty(pmdval)) 3234616b8371SZi Yan set_page_dirty(page); 32354dd845b5SAlistair Popple if (pmd_write(pmdval)) 32364dd845b5SAlistair Popple entry = make_writable_migration_entry(page_to_pfn(page)); 32376c287605SDavid Hildenbrand else if (anon_exclusive) 32386c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); 32394dd845b5SAlistair Popple else 32404dd845b5SAlistair Popple entry = make_readable_migration_entry(page_to_pfn(page)); 32412e346877SPeter Xu if (pmd_young(pmdval)) 32422e346877SPeter Xu entry = make_migration_entry_young(entry); 32432e346877SPeter Xu if (pmd_dirty(pmdval)) 32442e346877SPeter Xu entry = make_migration_entry_dirty(entry); 3245ab6e3d09SNaoya Horiguchi pmdswp = swp_entry_to_pmd(entry); 3246ab6e3d09SNaoya Horiguchi if (pmd_soft_dirty(pmdval)) 3247ab6e3d09SNaoya Horiguchi pmdswp = pmd_swp_mksoft_dirty(pmdswp); 3248ab6e3d09SNaoya Horiguchi set_pmd_at(mm, address, pvmw->pmd, pmdswp); 3249cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 3250616b8371SZi Yan put_page(page); 3251283fd6feSAnshuman Khandual trace_set_migration_pmd(address, pmd_val(pmdswp)); 32527f5abe60SDavid Hildenbrand 32537f5abe60SDavid Hildenbrand return 0; 3254616b8371SZi Yan } 3255616b8371SZi Yan 3256616b8371SZi Yan void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 3257616b8371SZi Yan { 3258616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3259616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3260616b8371SZi Yan unsigned long address = pvmw->address; 32614fba8f2aSMiaohe Lin unsigned long haddr = address & HPAGE_PMD_MASK; 3262616b8371SZi Yan pmd_t pmde; 3263616b8371SZi Yan swp_entry_t entry; 3264616b8371SZi Yan 3265616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 3266616b8371SZi Yan return; 3267616b8371SZi Yan 3268616b8371SZi Yan entry = pmd_to_swp_entry(*pvmw->pmd); 3269616b8371SZi Yan get_page(new); 32702e346877SPeter Xu pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); 3271ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pvmw->pmd)) 3272ab6e3d09SNaoya Horiguchi pmde = pmd_mksoft_dirty(pmde); 32734dd845b5SAlistair Popple if (is_writable_migration_entry(entry)) 3274f55e1014SLinus Torvalds pmde = maybe_pmd_mkwrite(pmde, vma); 32758f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*pvmw->pmd)) 3276f1eb1bacSPeter Xu pmde = pmd_mkuffd_wp(pmde); 32772e346877SPeter Xu if (!is_migration_entry_young(entry)) 32782e346877SPeter Xu pmde = pmd_mkold(pmde); 32792e346877SPeter Xu /* NOTE: this may contain setting soft-dirty on some archs */ 32802e346877SPeter Xu if (PageDirty(new) && is_migration_entry_dirty(entry)) 32812e346877SPeter Xu pmde = pmd_mkdirty(pmde); 3282616b8371SZi Yan 32836c287605SDavid Hildenbrand if (PageAnon(new)) { 32846c287605SDavid Hildenbrand rmap_t rmap_flags = RMAP_COMPOUND; 32856c287605SDavid Hildenbrand 32866c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) 32876c287605SDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 32886c287605SDavid Hildenbrand 32894fba8f2aSMiaohe Lin page_add_anon_rmap(new, vma, haddr, rmap_flags); 32906c287605SDavid Hildenbrand } else { 3291cea86fe2SHugh Dickins page_add_file_rmap(new, vma, true); 32926c287605SDavid Hildenbrand } 32936c287605SDavid Hildenbrand VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); 32944fba8f2aSMiaohe Lin set_pmd_at(mm, haddr, pvmw->pmd, pmde); 32955cbcf225SMuchun Song 32965cbcf225SMuchun Song /* No need to invalidate - it was non-present before */ 3297616b8371SZi Yan update_mmu_cache_pmd(vma, address, pvmw->pmd); 3298283fd6feSAnshuman Khandual trace_remove_migration_pmd(address, pmd_val(pmde)); 3299616b8371SZi Yan } 3300616b8371SZi Yan #endif 3301