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 */ 913c556d24SPeter Xu if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED)) 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)) 1222cf13384SDavid Stevens return shmem_is_huge(file_inode(vma->vm_file), vma->vm_pgoff, 1232cf13384SDavid Stevens !enforce_sysfs, vma->vm_mm, vm_flags); 1249fec5168SYang Shi 125a7f4e6e4SZach O'Keefe /* Enforce sysfs THP requirements as necessary */ 126a7f4e6e4SZach O'Keefe if (enforce_sysfs && 127a7f4e6e4SZach O'Keefe (!hugepage_flags_enabled() || (!(vm_flags & VM_HUGEPAGE) && 128a7f4e6e4SZach O'Keefe !hugepage_flags_always()))) 1299fec5168SYang Shi return false; 1309fec5168SYang Shi 1319fec5168SYang Shi /* Only regular file is valid */ 1327da4e2cbSYang Shi if (!in_pf && file_thp_enabled(vma)) 13378d12c19SYang Shi return true; 1347635d9cbSMichal Hocko 1359fec5168SYang Shi if (!vma_is_anonymous(vma)) 1367635d9cbSMichal Hocko return false; 1379fec5168SYang Shi 1389fec5168SYang Shi if (vma_is_temporary_stack(vma)) 1399fec5168SYang Shi return false; 1409fec5168SYang Shi 1419fec5168SYang Shi /* 1429fec5168SYang Shi * THPeligible bit of smaps should show 1 for proper VMAs even 1439fec5168SYang Shi * though anon_vma is not initialized yet. 1447da4e2cbSYang Shi * 1457da4e2cbSYang Shi * Allow page fault since anon_vma may be not initialized until 1467da4e2cbSYang Shi * the first page fault. 1479fec5168SYang Shi */ 1489fec5168SYang Shi if (!vma->anon_vma) 1497da4e2cbSYang Shi return (smaps || in_pf); 1509fec5168SYang Shi 1519fec5168SYang Shi return true; 1527635d9cbSMichal Hocko } 1537635d9cbSMichal Hocko 154aaa9705bSMiaohe Lin static bool get_huge_zero_page(void) 15597ae1749SKirill A. Shutemov { 15697ae1749SKirill A. Shutemov struct page *zero_page; 15797ae1749SKirill A. Shutemov retry: 15897ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 159aaa9705bSMiaohe Lin return true; 16097ae1749SKirill A. Shutemov 16197ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 16297ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 163d8a8e1f0SKirill A. Shutemov if (!zero_page) { 164d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 165aaa9705bSMiaohe Lin return false; 166d8a8e1f0SKirill A. Shutemov } 16797ae1749SKirill A. Shutemov preempt_disable(); 1685918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 16997ae1749SKirill A. Shutemov preempt_enable(); 1705ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 17197ae1749SKirill A. Shutemov goto retry; 17297ae1749SKirill A. Shutemov } 1733b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); 17497ae1749SKirill A. Shutemov 17597ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 17697ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 17797ae1749SKirill A. Shutemov preempt_enable(); 178f4981502SLiu Shixin count_vm_event(THP_ZERO_PAGE_ALLOC); 179aaa9705bSMiaohe Lin return true; 18097ae1749SKirill A. Shutemov } 18197ae1749SKirill A. Shutemov 1826fcb52a5SAaron Lu static void put_huge_zero_page(void) 18397ae1749SKirill A. Shutemov { 18497ae1749SKirill A. Shutemov /* 18597ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 18697ae1749SKirill A. Shutemov * last reference. 18797ae1749SKirill A. Shutemov */ 18897ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 18997ae1749SKirill A. Shutemov } 19097ae1749SKirill A. Shutemov 1916fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 1926fcb52a5SAaron Lu { 1936fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1946fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1956fcb52a5SAaron Lu 1966fcb52a5SAaron Lu if (!get_huge_zero_page()) 1976fcb52a5SAaron Lu return NULL; 1986fcb52a5SAaron Lu 1996fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2006fcb52a5SAaron Lu put_huge_zero_page(); 2016fcb52a5SAaron Lu 2026fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 2036fcb52a5SAaron Lu } 2046fcb52a5SAaron Lu 2056fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 2066fcb52a5SAaron Lu { 2076fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2086fcb52a5SAaron Lu put_huge_zero_page(); 2096fcb52a5SAaron Lu } 2106fcb52a5SAaron Lu 21148896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 21297ae1749SKirill A. Shutemov struct shrink_control *sc) 21397ae1749SKirill A. Shutemov { 21497ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 21597ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 21648896466SGlauber Costa } 21797ae1749SKirill A. Shutemov 21848896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 21948896466SGlauber Costa struct shrink_control *sc) 22048896466SGlauber Costa { 22197ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2225918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2235918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2243b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, ~0UL); 2255ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 22648896466SGlauber Costa return HPAGE_PMD_NR; 22797ae1749SKirill A. Shutemov } 22897ae1749SKirill A. Shutemov 22997ae1749SKirill A. Shutemov return 0; 23097ae1749SKirill A. Shutemov } 23197ae1749SKirill A. Shutemov 23297ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 23348896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 23448896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 23597ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 23697ae1749SKirill A. Shutemov }; 23797ae1749SKirill A. Shutemov 23871e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 23971e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 24071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 24171e3aac0SAndrea Arcangeli { 242bfb0ffebSJoe Perches const char *output; 243bfb0ffebSJoe Perches 244444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 245bfb0ffebSJoe Perches output = "[always] madvise never"; 246bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 247bfb0ffebSJoe Perches &transparent_hugepage_flags)) 248bfb0ffebSJoe Perches output = "always [madvise] never"; 249444eb2a4SMel Gorman else 250bfb0ffebSJoe Perches output = "always madvise [never]"; 251bfb0ffebSJoe Perches 252bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 25371e3aac0SAndrea Arcangeli } 254444eb2a4SMel Gorman 25571e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 25671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 25771e3aac0SAndrea Arcangeli const char *buf, size_t count) 25871e3aac0SAndrea Arcangeli { 25921440d7eSDavid Rientjes ssize_t ret = count; 260ba76149fSAndrea Arcangeli 261f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 26221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 26321440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 264f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 26521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 26621440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 267f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 26821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 26921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 27021440d7eSDavid Rientjes } else 27121440d7eSDavid Rientjes ret = -EINVAL; 272ba76149fSAndrea Arcangeli 273ba76149fSAndrea Arcangeli if (ret > 0) { 274b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 275ba76149fSAndrea Arcangeli if (err) 276ba76149fSAndrea Arcangeli ret = err; 277ba76149fSAndrea Arcangeli } 278ba76149fSAndrea Arcangeli return ret; 27971e3aac0SAndrea Arcangeli } 28037139bb0SMiaohe Lin 28137139bb0SMiaohe Lin static struct kobj_attribute enabled_attr = __ATTR_RW(enabled); 28271e3aac0SAndrea Arcangeli 283b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 28471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 28571e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 28671e3aac0SAndrea Arcangeli { 287bfb0ffebSJoe Perches return sysfs_emit(buf, "%d\n", 288e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 28971e3aac0SAndrea Arcangeli } 290e27e6151SBen Hutchings 291b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 29271e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 29371e3aac0SAndrea Arcangeli const char *buf, size_t count, 29471e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 29571e3aac0SAndrea Arcangeli { 296e27e6151SBen Hutchings unsigned long value; 297e27e6151SBen Hutchings int ret; 298e27e6151SBen Hutchings 299e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 300e27e6151SBen Hutchings if (ret < 0) 301e27e6151SBen Hutchings return ret; 302e27e6151SBen Hutchings if (value > 1) 30371e3aac0SAndrea Arcangeli return -EINVAL; 30471e3aac0SAndrea Arcangeli 305e27e6151SBen Hutchings if (value) 306e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 307e27e6151SBen Hutchings else 308e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 309e27e6151SBen Hutchings 31071e3aac0SAndrea Arcangeli return count; 31171e3aac0SAndrea Arcangeli } 31271e3aac0SAndrea Arcangeli 31371e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 31471e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 31571e3aac0SAndrea Arcangeli { 316bfb0ffebSJoe Perches const char *output; 317bfb0ffebSJoe Perches 318bfb0ffebSJoe Perches if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, 319bfb0ffebSJoe Perches &transparent_hugepage_flags)) 320bfb0ffebSJoe Perches output = "[always] defer defer+madvise madvise never"; 321bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, 322bfb0ffebSJoe Perches &transparent_hugepage_flags)) 323bfb0ffebSJoe Perches output = "always [defer] defer+madvise madvise never"; 324bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, 325bfb0ffebSJoe Perches &transparent_hugepage_flags)) 326bfb0ffebSJoe Perches output = "always defer [defer+madvise] madvise never"; 327bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, 328bfb0ffebSJoe Perches &transparent_hugepage_flags)) 329bfb0ffebSJoe Perches output = "always defer defer+madvise [madvise] never"; 330bfb0ffebSJoe Perches else 331bfb0ffebSJoe Perches output = "always defer defer+madvise madvise [never]"; 332bfb0ffebSJoe Perches 333bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 33471e3aac0SAndrea Arcangeli } 33521440d7eSDavid Rientjes 33671e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 33771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 33871e3aac0SAndrea Arcangeli const char *buf, size_t count) 33971e3aac0SAndrea Arcangeli { 340f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 34121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 34221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 34321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 34421440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 345f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer+madvise")) { 34621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 34721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 34821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 34921440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 350f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer")) { 3514fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 3524fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 3534fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 3544fad7fb6SDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 355f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 35621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 35721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 35821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 35921440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 360f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 36121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 36221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 36321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 36421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 36521440d7eSDavid Rientjes } else 36621440d7eSDavid Rientjes return -EINVAL; 36721440d7eSDavid Rientjes 36821440d7eSDavid Rientjes return count; 36971e3aac0SAndrea Arcangeli } 37037139bb0SMiaohe Lin static struct kobj_attribute defrag_attr = __ATTR_RW(defrag); 37171e3aac0SAndrea Arcangeli 37279da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 37379da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 37479da5407SKirill A. Shutemov { 375b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 37679da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 37779da5407SKirill A. Shutemov } 37879da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 37979da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 38079da5407SKirill A. Shutemov { 381b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 38279da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 38379da5407SKirill A. Shutemov } 38437139bb0SMiaohe Lin static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page); 38549920d28SHugh Dickins 38649920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 38749920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 38849920d28SHugh Dickins { 389ae7a927dSJoe Perches return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); 39049920d28SHugh Dickins } 39149920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 39249920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 39349920d28SHugh Dickins 39471e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 39571e3aac0SAndrea Arcangeli &enabled_attr.attr, 39671e3aac0SAndrea Arcangeli &defrag_attr.attr, 39779da5407SKirill A. Shutemov &use_zero_page_attr.attr, 39849920d28SHugh Dickins &hpage_pmd_size_attr.attr, 399396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_SHMEM 4005a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 4015a6e75f8SKirill A. Shutemov #endif 40271e3aac0SAndrea Arcangeli NULL, 40371e3aac0SAndrea Arcangeli }; 40471e3aac0SAndrea Arcangeli 4058aa95a21SArvind Yadav static const struct attribute_group hugepage_attr_group = { 40671e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 407ba76149fSAndrea Arcangeli }; 408ba76149fSAndrea Arcangeli 409569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 410569e5590SShaohua Li { 411569e5590SShaohua Li int err; 412569e5590SShaohua Li 413569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 414569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 415ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 416569e5590SShaohua Li return -ENOMEM; 417569e5590SShaohua Li } 418569e5590SShaohua Li 419569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 420569e5590SShaohua Li if (err) { 421ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 422569e5590SShaohua Li goto delete_obj; 423569e5590SShaohua Li } 424569e5590SShaohua Li 425569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 426569e5590SShaohua Li if (err) { 427ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 428569e5590SShaohua Li goto remove_hp_group; 429569e5590SShaohua Li } 430569e5590SShaohua Li 431569e5590SShaohua Li return 0; 432569e5590SShaohua Li 433569e5590SShaohua Li remove_hp_group: 434569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 435569e5590SShaohua Li delete_obj: 436569e5590SShaohua Li kobject_put(*hugepage_kobj); 437569e5590SShaohua Li return err; 438569e5590SShaohua Li } 439569e5590SShaohua Li 440569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 441569e5590SShaohua Li { 442569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 443569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 444569e5590SShaohua Li kobject_put(hugepage_kobj); 445569e5590SShaohua Li } 446569e5590SShaohua Li #else 447569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 448569e5590SShaohua Li { 449569e5590SShaohua Li return 0; 450569e5590SShaohua Li } 451569e5590SShaohua Li 452569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 453569e5590SShaohua Li { 454569e5590SShaohua Li } 45571e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 45671e3aac0SAndrea Arcangeli 45771e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 45871e3aac0SAndrea Arcangeli { 45971e3aac0SAndrea Arcangeli int err; 460569e5590SShaohua Li struct kobject *hugepage_kobj; 46171e3aac0SAndrea Arcangeli 4624b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 4633c556d24SPeter Xu transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED; 464569e5590SShaohua Li return -EINVAL; 4654b7167b9SAndrea Arcangeli } 4664b7167b9SAndrea Arcangeli 467ff20c2e0SKirill A. Shutemov /* 468ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 469ff20c2e0SKirill A. Shutemov */ 47023baf831SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER > MAX_ORDER); 471ff20c2e0SKirill A. Shutemov /* 472ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 473ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 474ff20c2e0SKirill A. Shutemov */ 475ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 476ff20c2e0SKirill A. Shutemov 477569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 478569e5590SShaohua Li if (err) 47965ebb64fSKirill A. Shutemov goto err_sysfs; 480ba76149fSAndrea Arcangeli 481b46e756fSKirill A. Shutemov err = khugepaged_init(); 482ba76149fSAndrea Arcangeli if (err) 48365ebb64fSKirill A. Shutemov goto err_slab; 484ba76149fSAndrea Arcangeli 485e33c267aSRoman Gushchin err = register_shrinker(&huge_zero_page_shrinker, "thp-zero"); 48665ebb64fSKirill A. Shutemov if (err) 48765ebb64fSKirill A. Shutemov goto err_hzp_shrinker; 488e33c267aSRoman Gushchin err = register_shrinker(&deferred_split_shrinker, "thp-deferred_split"); 4899a982250SKirill A. Shutemov if (err) 4909a982250SKirill A. Shutemov goto err_split_shrinker; 49197ae1749SKirill A. Shutemov 49297562cd2SRik van Riel /* 49397562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 49497562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 49597562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 49697562cd2SRik van Riel */ 497ca79b0c2SArun KS if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { 49897562cd2SRik van Riel transparent_hugepage_flags = 0; 49979553da2SKirill A. Shutemov return 0; 50079553da2SKirill A. Shutemov } 50197562cd2SRik van Riel 50279553da2SKirill A. Shutemov err = start_stop_khugepaged(); 50365ebb64fSKirill A. Shutemov if (err) 50465ebb64fSKirill A. Shutemov goto err_khugepaged; 505ba76149fSAndrea Arcangeli 506569e5590SShaohua Li return 0; 50765ebb64fSKirill A. Shutemov err_khugepaged: 5089a982250SKirill A. Shutemov unregister_shrinker(&deferred_split_shrinker); 5099a982250SKirill A. Shutemov err_split_shrinker: 51065ebb64fSKirill A. Shutemov unregister_shrinker(&huge_zero_page_shrinker); 51165ebb64fSKirill A. Shutemov err_hzp_shrinker: 512b46e756fSKirill A. Shutemov khugepaged_destroy(); 51365ebb64fSKirill A. Shutemov err_slab: 514569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 51565ebb64fSKirill A. Shutemov err_sysfs: 516ba76149fSAndrea Arcangeli return err; 51771e3aac0SAndrea Arcangeli } 518a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 51971e3aac0SAndrea Arcangeli 52071e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 52171e3aac0SAndrea Arcangeli { 52271e3aac0SAndrea Arcangeli int ret = 0; 52371e3aac0SAndrea Arcangeli if (!str) 52471e3aac0SAndrea Arcangeli goto out; 52571e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 52671e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 52771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 52871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 52971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53071e3aac0SAndrea Arcangeli ret = 1; 53171e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 53271e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 53371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53471e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 53571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53671e3aac0SAndrea Arcangeli ret = 1; 53771e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 53871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 53971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 54071e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 54171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 54271e3aac0SAndrea Arcangeli ret = 1; 54371e3aac0SAndrea Arcangeli } 54471e3aac0SAndrea Arcangeli out: 54571e3aac0SAndrea Arcangeli if (!ret) 546ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 54771e3aac0SAndrea Arcangeli return ret; 54871e3aac0SAndrea Arcangeli } 54971e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 55071e3aac0SAndrea Arcangeli 551f55e1014SLinus Torvalds pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 55271e3aac0SAndrea Arcangeli { 553f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 55471e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 55571e3aac0SAndrea Arcangeli return pmd; 55671e3aac0SAndrea Arcangeli } 55771e3aac0SAndrea Arcangeli 55887eaceb3SYang Shi #ifdef CONFIG_MEMCG 559f8baa6beSMatthew Wilcox (Oracle) static inline 560f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *get_deferred_split_queue(struct folio *folio) 5619a982250SKirill A. Shutemov { 562f8baa6beSMatthew Wilcox (Oracle) struct mem_cgroup *memcg = folio_memcg(folio); 563f8baa6beSMatthew Wilcox (Oracle) struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); 56487eaceb3SYang Shi 56587eaceb3SYang Shi if (memcg) 56687eaceb3SYang Shi return &memcg->deferred_split_queue; 56787eaceb3SYang Shi else 56887eaceb3SYang Shi return &pgdat->deferred_split_queue; 5699a982250SKirill A. Shutemov } 57087eaceb3SYang Shi #else 571f8baa6beSMatthew Wilcox (Oracle) static inline 572f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *get_deferred_split_queue(struct folio *folio) 57387eaceb3SYang Shi { 574f8baa6beSMatthew Wilcox (Oracle) struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); 57587eaceb3SYang Shi 57687eaceb3SYang Shi return &pgdat->deferred_split_queue; 57787eaceb3SYang Shi } 57887eaceb3SYang Shi #endif 5799a982250SKirill A. Shutemov 580*da6e7bf3SMatthew Wilcox (Oracle) void folio_prep_large_rmappable(struct folio *folio) 5819a982250SKirill A. Shutemov { 5828991de90SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); 5838991de90SMatthew Wilcox (Oracle) INIT_LIST_HEAD(&folio->_deferred_list); 584b95826c9SSidhartha Kumar folio_set_compound_dtor(folio, TRANSHUGE_PAGE_DTOR); 5859a982250SKirill A. Shutemov } 5869a982250SKirill A. Shutemov 587562beb72SMiaohe Lin static inline bool is_transparent_hugepage(struct page *page) 588005ba37cSSean Christopherson { 589f04029f3SMatthew Wilcox (Oracle) struct folio *folio; 590f04029f3SMatthew Wilcox (Oracle) 591005ba37cSSean Christopherson if (!PageCompound(page)) 592fa1f68ccSZou Wei return false; 593005ba37cSSean Christopherson 594f04029f3SMatthew Wilcox (Oracle) folio = page_folio(page); 595f04029f3SMatthew Wilcox (Oracle) return is_huge_zero_page(&folio->page) || 596f04029f3SMatthew Wilcox (Oracle) folio->_folio_dtor == TRANSHUGE_PAGE_DTOR; 597005ba37cSSean Christopherson } 598005ba37cSSean Christopherson 59997d3d0f9SKirill A. Shutemov static unsigned long __thp_get_unmapped_area(struct file *filp, 60097d3d0f9SKirill A. Shutemov unsigned long addr, unsigned long len, 60174d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 60274d2fad1SToshi Kani { 60374d2fad1SToshi Kani loff_t off_end = off + len; 60474d2fad1SToshi Kani loff_t off_align = round_up(off, size); 60597d3d0f9SKirill A. Shutemov unsigned long len_pad, ret; 60674d2fad1SToshi Kani 60774d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 60874d2fad1SToshi Kani return 0; 60974d2fad1SToshi Kani 61074d2fad1SToshi Kani len_pad = len + size; 61174d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 61274d2fad1SToshi Kani return 0; 61374d2fad1SToshi Kani 61497d3d0f9SKirill A. Shutemov ret = current->mm->get_unmapped_area(filp, addr, len_pad, 61574d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 61697d3d0f9SKirill A. Shutemov 61797d3d0f9SKirill A. Shutemov /* 61897d3d0f9SKirill A. Shutemov * The failure might be due to length padding. The caller will retry 61997d3d0f9SKirill A. Shutemov * without the padding. 62097d3d0f9SKirill A. Shutemov */ 62197d3d0f9SKirill A. Shutemov if (IS_ERR_VALUE(ret)) 62274d2fad1SToshi Kani return 0; 62374d2fad1SToshi Kani 62497d3d0f9SKirill A. Shutemov /* 62597d3d0f9SKirill A. Shutemov * Do not try to align to THP boundary if allocation at the address 62697d3d0f9SKirill A. Shutemov * hint succeeds. 62797d3d0f9SKirill A. Shutemov */ 62897d3d0f9SKirill A. Shutemov if (ret == addr) 62974d2fad1SToshi Kani return addr; 63097d3d0f9SKirill A. Shutemov 63197d3d0f9SKirill A. Shutemov ret += (off - ret) & (size - 1); 63297d3d0f9SKirill A. Shutemov return ret; 63374d2fad1SToshi Kani } 63474d2fad1SToshi Kani 63574d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 63674d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 63774d2fad1SToshi Kani { 63897d3d0f9SKirill A. Shutemov unsigned long ret; 63974d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 64074d2fad1SToshi Kani 64197d3d0f9SKirill A. Shutemov ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); 64297d3d0f9SKirill A. Shutemov if (ret) 64397d3d0f9SKirill A. Shutemov return ret; 6441854bc6eSWilliam Kucharski 64574d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 64674d2fad1SToshi Kani } 64774d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 64874d2fad1SToshi Kani 6492b740303SSouptick Joarder static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, 6502b740303SSouptick Joarder struct page *page, gfp_t gfp) 65171e3aac0SAndrea Arcangeli { 65282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 653cfe3236dSKefeng Wang struct folio *folio = page_folio(page); 65471e3aac0SAndrea Arcangeli pgtable_t pgtable; 65582b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 6562b740303SSouptick Joarder vm_fault_t ret = 0; 65771e3aac0SAndrea Arcangeli 658cfe3236dSKefeng Wang VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 65900501b53SJohannes Weiner 660cfe3236dSKefeng Wang if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) { 661cfe3236dSKefeng Wang folio_put(folio); 6626b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 66385b9f46eSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK_CHARGE); 6646b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 6656b251fc9SAndrea Arcangeli } 666cfe3236dSKefeng Wang folio_throttle_swaprate(folio, gfp); 66771e3aac0SAndrea Arcangeli 6684cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 66900501b53SJohannes Weiner if (unlikely(!pgtable)) { 6706b31d595SMichal Hocko ret = VM_FAULT_OOM; 6716b31d595SMichal Hocko goto release; 67200501b53SJohannes Weiner } 67300501b53SJohannes Weiner 674c79b57e4SHuang Ying clear_huge_page(page, vmf->address, HPAGE_PMD_NR); 67552f37629SMinchan Kim /* 676cfe3236dSKefeng Wang * The memory barrier inside __folio_mark_uptodate makes sure that 67752f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 67852f37629SMinchan Kim * write. 67952f37629SMinchan Kim */ 680cfe3236dSKefeng Wang __folio_mark_uptodate(folio); 68171e3aac0SAndrea Arcangeli 68282b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 68382b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 6846b31d595SMichal Hocko goto unlock_release; 68571e3aac0SAndrea Arcangeli } else { 68671e3aac0SAndrea Arcangeli pmd_t entry; 6876b251fc9SAndrea Arcangeli 6886b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 6896b31d595SMichal Hocko if (ret) 6906b31d595SMichal Hocko goto unlock_release; 6916b31d595SMichal Hocko 6926b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 6936b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 69482b0f8c3SJan Kara spin_unlock(vmf->ptl); 695cfe3236dSKefeng Wang folio_put(folio); 696bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 6978fd5eda4SMiaohe Lin ret = handle_userfault(vmf, VM_UFFD_MISSING); 6988fd5eda4SMiaohe Lin VM_BUG_ON(ret & VM_FAULT_FALLBACK); 6998fd5eda4SMiaohe Lin return ret; 7006b251fc9SAndrea Arcangeli } 7016b251fc9SAndrea Arcangeli 7023122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 703f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 704cfe3236dSKefeng Wang folio_add_new_anon_rmap(folio, vma, haddr); 705cfe3236dSKefeng Wang folio_add_lru_vma(folio, vma); 70682b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 70782b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 708fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 709bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 710c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 71182b0f8c3SJan Kara spin_unlock(vmf->ptl); 7126b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 7139d82c694SJohannes Weiner count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); 71471e3aac0SAndrea Arcangeli } 71571e3aac0SAndrea Arcangeli 716aa2e878eSDavid Rientjes return 0; 7176b31d595SMichal Hocko unlock_release: 7186b31d595SMichal Hocko spin_unlock(vmf->ptl); 7196b31d595SMichal Hocko release: 7206b31d595SMichal Hocko if (pgtable) 7216b31d595SMichal Hocko pte_free(vma->vm_mm, pgtable); 722cfe3236dSKefeng Wang folio_put(folio); 7236b31d595SMichal Hocko return ret; 7246b31d595SMichal Hocko 72571e3aac0SAndrea Arcangeli } 72671e3aac0SAndrea Arcangeli 727444eb2a4SMel Gorman /* 72821440d7eSDavid Rientjes * always: directly stall for all thp allocations 72921440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 73021440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 73121440d7eSDavid Rientjes * fail if not immediately available 73221440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 73321440d7eSDavid Rientjes * available 73421440d7eSDavid Rientjes * never: never stall for any thp allocation 735444eb2a4SMel Gorman */ 736164cc4feSRik van Riel gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) 7370bbbc0b3SAndrea Arcangeli { 738164cc4feSRik van Riel const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); 73989c83fb5SMichal Hocko 740ac79f78dSDavid Rientjes /* Always do synchronous compaction */ 74121440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 742a8282608SAndrea Arcangeli return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 743ac79f78dSDavid Rientjes 744ac79f78dSDavid Rientjes /* Kick kcompactd and fail quickly */ 74521440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 74619deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 747ac79f78dSDavid Rientjes 748ac79f78dSDavid Rientjes /* Synchronous compaction if madvised, otherwise kick kcompactd */ 74921440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 75019deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 75119deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 752ac79f78dSDavid Rientjes __GFP_KSWAPD_RECLAIM); 753ac79f78dSDavid Rientjes 754ac79f78dSDavid Rientjes /* Only do synchronous compaction if madvised */ 75521440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 75619deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 75719deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); 758ac79f78dSDavid Rientjes 75919deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT; 760444eb2a4SMel Gorman } 761444eb2a4SMel Gorman 762c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 7632efeb8daSMiaohe Lin static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 76497ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 7655918d10aSKirill A. Shutemov struct page *zero_page) 766fc9fe822SKirill A. Shutemov { 767fc9fe822SKirill A. Shutemov pmd_t entry; 7687c414164SAndrew Morton if (!pmd_none(*pmd)) 7692efeb8daSMiaohe Lin return; 7705918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 771fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 7726b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 773fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 774c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 775fc9fe822SKirill A. Shutemov } 776fc9fe822SKirill A. Shutemov 7772b740303SSouptick Joarder vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) 77871e3aac0SAndrea Arcangeli { 77982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 780077fcf11SAneesh Kumar K.V gfp_t gfp; 781cb196ee1SMatthew Wilcox (Oracle) struct folio *folio; 78282b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 78371e3aac0SAndrea Arcangeli 78443675e6fSYang Shi if (!transhuge_vma_suitable(vma, haddr)) 785c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 78671e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 78771e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 7884fa6893fSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 789d2081b2bSYang Shi 79082b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 791bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 79279da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 79380371957SKirill A. Shutemov pgtable_t pgtable; 7945918d10aSKirill A. Shutemov struct page *zero_page; 7952b740303SSouptick Joarder vm_fault_t ret; 7964cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 79780371957SKirill A. Shutemov if (unlikely(!pgtable)) 79880371957SKirill A. Shutemov return VM_FAULT_OOM; 7996fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 8005918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 801bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 80297ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 803c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 80497ae1749SKirill A. Shutemov } 80582b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 8066b251fc9SAndrea Arcangeli ret = 0; 80782b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 8086b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 8096b31d595SMichal Hocko if (ret) { 8106b31d595SMichal Hocko spin_unlock(vmf->ptl); 811bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 8126b31d595SMichal Hocko } else if (userfaultfd_missing(vma)) { 81382b0f8c3SJan Kara spin_unlock(vmf->ptl); 814bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 81582b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 8166b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 8176b251fc9SAndrea Arcangeli } else { 818bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 81982b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 820fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 82182b0f8c3SJan Kara spin_unlock(vmf->ptl); 8226b251fc9SAndrea Arcangeli } 823bfe8cc1dSGerald Schaefer } else { 82482b0f8c3SJan Kara spin_unlock(vmf->ptl); 825bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 826bfe8cc1dSGerald Schaefer } 8276b251fc9SAndrea Arcangeli return ret; 82880371957SKirill A. Shutemov } 829164cc4feSRik van Riel gfp = vma_thp_gfp_mask(vma); 830cb196ee1SMatthew Wilcox (Oracle) folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); 831cb196ee1SMatthew Wilcox (Oracle) if (unlikely(!folio)) { 83281ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 833c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 83481ab4201SAndi Kleen } 835cb196ee1SMatthew Wilcox (Oracle) return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); 83671e3aac0SAndrea Arcangeli } 83771e3aac0SAndrea Arcangeli 838ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 8393b6521f5SOliver O'Halloran pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, 8403b6521f5SOliver O'Halloran pgtable_t pgtable) 8415cad465dSMatthew Wilcox { 8425cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 8435cad465dSMatthew Wilcox pmd_t entry; 8445cad465dSMatthew Wilcox spinlock_t *ptl; 8455cad465dSMatthew Wilcox 8465cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 847c6f3c5eeSAneesh Kumar K.V if (!pmd_none(*pmd)) { 848c6f3c5eeSAneesh Kumar K.V if (write) { 849c6f3c5eeSAneesh Kumar K.V if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { 850c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); 851c6f3c5eeSAneesh Kumar K.V goto out_unlock; 852c6f3c5eeSAneesh Kumar K.V } 853c6f3c5eeSAneesh Kumar K.V entry = pmd_mkyoung(*pmd); 854c6f3c5eeSAneesh Kumar K.V entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 855c6f3c5eeSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) 856c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 857c6f3c5eeSAneesh Kumar K.V } 858c6f3c5eeSAneesh Kumar K.V 859c6f3c5eeSAneesh Kumar K.V goto out_unlock; 860c6f3c5eeSAneesh Kumar K.V } 861c6f3c5eeSAneesh Kumar K.V 862f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 863f25748e3SDan Williams if (pfn_t_devmap(pfn)) 864f25748e3SDan Williams entry = pmd_mkdevmap(entry); 8655cad465dSMatthew Wilcox if (write) { 866f55e1014SLinus Torvalds entry = pmd_mkyoung(pmd_mkdirty(entry)); 867f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(entry, vma); 8685cad465dSMatthew Wilcox } 8693b6521f5SOliver O'Halloran 8703b6521f5SOliver O'Halloran if (pgtable) { 8713b6521f5SOliver O'Halloran pgtable_trans_huge_deposit(mm, pmd, pgtable); 872c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 873c6f3c5eeSAneesh Kumar K.V pgtable = NULL; 8743b6521f5SOliver O'Halloran } 8753b6521f5SOliver O'Halloran 8765cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 8775cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 878c6f3c5eeSAneesh Kumar K.V 879c6f3c5eeSAneesh Kumar K.V out_unlock: 8805cad465dSMatthew Wilcox spin_unlock(ptl); 881c6f3c5eeSAneesh Kumar K.V if (pgtable) 882c6f3c5eeSAneesh Kumar K.V pte_free(mm, pgtable); 8835cad465dSMatthew Wilcox } 8845cad465dSMatthew Wilcox 8859a9731b1SThomas Hellstrom (VMware) /** 8867b806d22SLorenzo Stoakes * vmf_insert_pfn_pmd - insert a pmd size pfn 8879a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 8889a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 8899a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 8909a9731b1SThomas Hellstrom (VMware) * 8917b806d22SLorenzo Stoakes * Insert a pmd size pfn. See vmf_insert_pfn() for additional info. 8929a9731b1SThomas Hellstrom (VMware) * 8939a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 8949a9731b1SThomas Hellstrom (VMware) */ 8957b806d22SLorenzo Stoakes vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) 8965cad465dSMatthew Wilcox { 897fce86ff5SDan Williams unsigned long addr = vmf->address & PMD_MASK; 898fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 8997b806d22SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 9003b6521f5SOliver O'Halloran pgtable_t pgtable = NULL; 901fce86ff5SDan Williams 9025cad465dSMatthew Wilcox /* 9035cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 9045cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 9055cad465dSMatthew Wilcox * can't support a 'special' bit. 9065cad465dSMatthew Wilcox */ 907e1fb4a08SDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 908e1fb4a08SDave Jiang !pfn_t_devmap(pfn)); 9095cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 9105cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 9115cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 9125cad465dSMatthew Wilcox 9135cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 9145cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 915308a047cSBorislav Petkov 9163b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) { 9174cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 9183b6521f5SOliver O'Halloran if (!pgtable) 9193b6521f5SOliver O'Halloran return VM_FAULT_OOM; 9203b6521f5SOliver O'Halloran } 9213b6521f5SOliver O'Halloran 922308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 923308a047cSBorislav Petkov 924fce86ff5SDan Williams insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); 925ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 9265cad465dSMatthew Wilcox } 9277b806d22SLorenzo Stoakes EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); 9285cad465dSMatthew Wilcox 929a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 930f55e1014SLinus Torvalds static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 931a00cc7d9SMatthew Wilcox { 932f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 933a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 934a00cc7d9SMatthew Wilcox return pud; 935a00cc7d9SMatthew Wilcox } 936a00cc7d9SMatthew Wilcox 937a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 9387b806d22SLorenzo Stoakes pud_t *pud, pfn_t pfn, bool write) 939a00cc7d9SMatthew Wilcox { 940a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 9417b806d22SLorenzo Stoakes pgprot_t prot = vma->vm_page_prot; 942a00cc7d9SMatthew Wilcox pud_t entry; 943a00cc7d9SMatthew Wilcox spinlock_t *ptl; 944a00cc7d9SMatthew Wilcox 945a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 946c6f3c5eeSAneesh Kumar K.V if (!pud_none(*pud)) { 947c6f3c5eeSAneesh Kumar K.V if (write) { 948c6f3c5eeSAneesh Kumar K.V if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { 949c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pud(*pud)); 950c6f3c5eeSAneesh Kumar K.V goto out_unlock; 951c6f3c5eeSAneesh Kumar K.V } 952c6f3c5eeSAneesh Kumar K.V entry = pud_mkyoung(*pud); 953c6f3c5eeSAneesh Kumar K.V entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); 954c6f3c5eeSAneesh Kumar K.V if (pudp_set_access_flags(vma, addr, pud, entry, 1)) 955c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pud(vma, addr, pud); 956c6f3c5eeSAneesh Kumar K.V } 957c6f3c5eeSAneesh Kumar K.V goto out_unlock; 958c6f3c5eeSAneesh Kumar K.V } 959c6f3c5eeSAneesh Kumar K.V 960a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 961a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 962a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 963a00cc7d9SMatthew Wilcox if (write) { 964f55e1014SLinus Torvalds entry = pud_mkyoung(pud_mkdirty(entry)); 965f55e1014SLinus Torvalds entry = maybe_pud_mkwrite(entry, vma); 966a00cc7d9SMatthew Wilcox } 967a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 968a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 969c6f3c5eeSAneesh Kumar K.V 970c6f3c5eeSAneesh Kumar K.V out_unlock: 971a00cc7d9SMatthew Wilcox spin_unlock(ptl); 972a00cc7d9SMatthew Wilcox } 973a00cc7d9SMatthew Wilcox 9749a9731b1SThomas Hellstrom (VMware) /** 9757b806d22SLorenzo Stoakes * vmf_insert_pfn_pud - insert a pud size pfn 9769a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 9779a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 9789a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 9799a9731b1SThomas Hellstrom (VMware) * 9807b806d22SLorenzo Stoakes * Insert a pud size pfn. See vmf_insert_pfn() for additional info. 9819a9731b1SThomas Hellstrom (VMware) * 9829a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 9839a9731b1SThomas Hellstrom (VMware) */ 9847b806d22SLorenzo Stoakes vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) 985a00cc7d9SMatthew Wilcox { 986fce86ff5SDan Williams unsigned long addr = vmf->address & PUD_MASK; 987fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 9887b806d22SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 989fce86ff5SDan Williams 990a00cc7d9SMatthew Wilcox /* 991a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 992a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 993a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 994a00cc7d9SMatthew Wilcox */ 99562ec0d8cSDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 99662ec0d8cSDave Jiang !pfn_t_devmap(pfn)); 997a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 998a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 999a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 1000a00cc7d9SMatthew Wilcox 1001a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 1002a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 1003a00cc7d9SMatthew Wilcox 1004a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 1005a00cc7d9SMatthew Wilcox 10067b806d22SLorenzo Stoakes insert_pfn_pud(vma, addr, vmf->pud, pfn, write); 1007a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 1008a00cc7d9SMatthew Wilcox } 10097b806d22SLorenzo Stoakes EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); 1010a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1011a00cc7d9SMatthew Wilcox 10123565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 1013a69e4717SMiaohe Lin pmd_t *pmd, bool write) 10143565fce3SDan Williams { 10153565fce3SDan Williams pmd_t _pmd; 10163565fce3SDan Williams 1017a8f97366SKirill A. Shutemov _pmd = pmd_mkyoung(*pmd); 1018a69e4717SMiaohe Lin if (write) 1019a8f97366SKirill A. Shutemov _pmd = pmd_mkdirty(_pmd); 10203565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 1021a69e4717SMiaohe Lin pmd, _pmd, write)) 10223565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 10233565fce3SDan Williams } 10243565fce3SDan Williams 10253565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 1026df06b37fSKeith Busch pmd_t *pmd, int flags, struct dev_pagemap **pgmap) 10273565fce3SDan Williams { 10283565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 10293565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 10303565fce3SDan Williams struct page *page; 10310f089235SLogan Gunthorpe int ret; 10323565fce3SDan Williams 10333565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 10343565fce3SDan Williams 1035f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pmd_write(*pmd)) 10363565fce3SDan Williams return NULL; 10373565fce3SDan Williams 10383565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 10393565fce3SDan Williams /* pass */; 10403565fce3SDan Williams else 10413565fce3SDan Williams return NULL; 10423565fce3SDan Williams 10433565fce3SDan Williams if (flags & FOLL_TOUCH) 1044a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 10453565fce3SDan Williams 10463565fce3SDan Williams /* 10473565fce3SDan Williams * device mapped pages can only be returned if the 10483565fce3SDan Williams * caller will manage the page reference count. 10493565fce3SDan Williams */ 10503faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 10513565fce3SDan Williams return ERR_PTR(-EEXIST); 10523565fce3SDan Williams 10533565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 1054df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1055df06b37fSKeith Busch if (!*pgmap) 10563565fce3SDan Williams return ERR_PTR(-EFAULT); 10573565fce3SDan Williams page = pfn_to_page(pfn); 10580f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 10590f089235SLogan Gunthorpe if (ret) 10600f089235SLogan Gunthorpe page = ERR_PTR(ret); 10613565fce3SDan Williams 10623565fce3SDan Williams return page; 10633565fce3SDan Williams } 10643565fce3SDan Williams 106571e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 106671e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 10678f34f1eaSPeter Xu struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 106871e3aac0SAndrea Arcangeli { 1069c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 107071e3aac0SAndrea Arcangeli struct page *src_page; 107171e3aac0SAndrea Arcangeli pmd_t pmd; 107212c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 1073628d47ceSKirill A. Shutemov int ret = -ENOMEM; 107471e3aac0SAndrea Arcangeli 1075628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 10768f34f1eaSPeter Xu if (!vma_is_anonymous(dst_vma)) 1077628d47ceSKirill A. Shutemov return 0; 1078628d47ceSKirill A. Shutemov 10794cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(dst_mm); 108071e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 108171e3aac0SAndrea Arcangeli goto out; 108271e3aac0SAndrea Arcangeli 1083c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 1084c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 1085c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 108671e3aac0SAndrea Arcangeli 108771e3aac0SAndrea Arcangeli ret = -EAGAIN; 108871e3aac0SAndrea Arcangeli pmd = *src_pmd; 108984c3fc4eSZi Yan 109084c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 109184c3fc4eSZi Yan if (unlikely(is_swap_pmd(pmd))) { 109284c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(pmd); 109384c3fc4eSZi Yan 109484c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(pmd)); 10956c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) { 10964dd845b5SAlistair Popple entry = make_readable_migration_entry( 10974dd845b5SAlistair Popple swp_offset(entry)); 109884c3fc4eSZi Yan pmd = swp_entry_to_pmd(entry); 1099ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*src_pmd)) 1100ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 11018f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*src_pmd)) 11028f34f1eaSPeter Xu pmd = pmd_swp_mkuffd_wp(pmd); 110384c3fc4eSZi Yan set_pmd_at(src_mm, addr, src_pmd, pmd); 110484c3fc4eSZi Yan } 1105dd8a67f9SZi Yan add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1106af5b0f6aSKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 1107dd8a67f9SZi Yan pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 11088f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11098f34f1eaSPeter Xu pmd = pmd_swp_clear_uffd_wp(pmd); 111084c3fc4eSZi Yan set_pmd_at(dst_mm, addr, dst_pmd, pmd); 111184c3fc4eSZi Yan ret = 0; 111284c3fc4eSZi Yan goto out_unlock; 111384c3fc4eSZi Yan } 111484c3fc4eSZi Yan #endif 111584c3fc4eSZi Yan 1116628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 111771e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 111871e3aac0SAndrea Arcangeli goto out_unlock; 111971e3aac0SAndrea Arcangeli } 1120fc9fe822SKirill A. Shutemov /* 1121c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 1122fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 1123fc9fe822SKirill A. Shutemov * a page table. 1124fc9fe822SKirill A. Shutemov */ 1125fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 112697ae1749SKirill A. Shutemov /* 112797ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 112897ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 112997ae1749SKirill A. Shutemov * reference. 113097ae1749SKirill A. Shutemov */ 11315fc7a5f6SPeter Xu mm_get_huge_zero_page(dst_mm); 11325fc7a5f6SPeter Xu goto out_zero_page; 1133fc9fe822SKirill A. Shutemov } 1134de466bd6SMel Gorman 113571e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 1136309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 1137d042035eSPeter Xu 1138fb3d824dSDavid Hildenbrand get_page(src_page); 1139fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { 1140fb3d824dSDavid Hildenbrand /* Page maybe pinned: split and retry the fault on PTEs. */ 1141fb3d824dSDavid Hildenbrand put_page(src_page); 1142d042035eSPeter Xu pte_free(dst_mm, pgtable); 1143d042035eSPeter Xu spin_unlock(src_ptl); 1144d042035eSPeter Xu spin_unlock(dst_ptl); 11458f34f1eaSPeter Xu __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); 1146d042035eSPeter Xu return -EAGAIN; 1147d042035eSPeter Xu } 114871e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 11495fc7a5f6SPeter Xu out_zero_page: 1150c4812909SKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 11515c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 115271e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 11538f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11548f34f1eaSPeter Xu pmd = pmd_clear_uffd_wp(pmd); 115571e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 115671e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 115771e3aac0SAndrea Arcangeli 115871e3aac0SAndrea Arcangeli ret = 0; 115971e3aac0SAndrea Arcangeli out_unlock: 1160c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 1161c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 116271e3aac0SAndrea Arcangeli out: 116371e3aac0SAndrea Arcangeli return ret; 116471e3aac0SAndrea Arcangeli } 116571e3aac0SAndrea Arcangeli 1166a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1167a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 11685fe653e9SMiaohe Lin pud_t *pud, bool write) 1169a00cc7d9SMatthew Wilcox { 1170a00cc7d9SMatthew Wilcox pud_t _pud; 1171a00cc7d9SMatthew Wilcox 1172a8f97366SKirill A. Shutemov _pud = pud_mkyoung(*pud); 11735fe653e9SMiaohe Lin if (write) 1174a8f97366SKirill A. Shutemov _pud = pud_mkdirty(_pud); 1175a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 11765fe653e9SMiaohe Lin pud, _pud, write)) 1177a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1178a00cc7d9SMatthew Wilcox } 1179a00cc7d9SMatthew Wilcox 1180a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 1181df06b37fSKeith Busch pud_t *pud, int flags, struct dev_pagemap **pgmap) 1182a00cc7d9SMatthew Wilcox { 1183a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 1184a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1185a00cc7d9SMatthew Wilcox struct page *page; 11860f089235SLogan Gunthorpe int ret; 1187a00cc7d9SMatthew Wilcox 1188a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 1189a00cc7d9SMatthew Wilcox 1190f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pud_write(*pud)) 1191a00cc7d9SMatthew Wilcox return NULL; 1192a00cc7d9SMatthew Wilcox 1193a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 1194a00cc7d9SMatthew Wilcox /* pass */; 1195a00cc7d9SMatthew Wilcox else 1196a00cc7d9SMatthew Wilcox return NULL; 1197a00cc7d9SMatthew Wilcox 1198a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 11995fe653e9SMiaohe Lin touch_pud(vma, addr, pud, flags & FOLL_WRITE); 1200a00cc7d9SMatthew Wilcox 1201a00cc7d9SMatthew Wilcox /* 1202a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 1203a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 12043faa52c0SJohn Hubbard * 12053faa52c0SJohn Hubbard * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: 1206a00cc7d9SMatthew Wilcox */ 12073faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 1208a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 1209a00cc7d9SMatthew Wilcox 1210a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 1211df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1212df06b37fSKeith Busch if (!*pgmap) 1213a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 1214a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 12150f089235SLogan Gunthorpe 12160f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 12170f089235SLogan Gunthorpe if (ret) 12180f089235SLogan Gunthorpe page = ERR_PTR(ret); 1219a00cc7d9SMatthew Wilcox 1220a00cc7d9SMatthew Wilcox return page; 1221a00cc7d9SMatthew Wilcox } 1222a00cc7d9SMatthew Wilcox 1223a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1224a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1225a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1226a00cc7d9SMatthew Wilcox { 1227a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1228a00cc7d9SMatthew Wilcox pud_t pud; 1229a00cc7d9SMatthew Wilcox int ret; 1230a00cc7d9SMatthew Wilcox 1231a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1232a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1233a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1234a00cc7d9SMatthew Wilcox 1235a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1236a00cc7d9SMatthew Wilcox pud = *src_pud; 1237a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1238a00cc7d9SMatthew Wilcox goto out_unlock; 1239a00cc7d9SMatthew Wilcox 1240a00cc7d9SMatthew Wilcox /* 1241a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1242a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1243a00cc7d9SMatthew Wilcox * a page table. 1244a00cc7d9SMatthew Wilcox */ 1245a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1246a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1247a00cc7d9SMatthew Wilcox } 1248a00cc7d9SMatthew Wilcox 1249fb3d824dSDavid Hildenbrand /* 1250fb3d824dSDavid Hildenbrand * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() 1251fb3d824dSDavid Hildenbrand * and split if duplicating fails. 1252fb3d824dSDavid Hildenbrand */ 1253a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1254a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1255a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1256a00cc7d9SMatthew Wilcox 1257a00cc7d9SMatthew Wilcox ret = 0; 1258a00cc7d9SMatthew Wilcox out_unlock: 1259a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1260a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1261a00cc7d9SMatthew Wilcox return ret; 1262a00cc7d9SMatthew Wilcox } 1263a00cc7d9SMatthew Wilcox 1264a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1265a00cc7d9SMatthew Wilcox { 1266a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1267a00cc7d9SMatthew Wilcox 1268a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1269a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1270a00cc7d9SMatthew Wilcox goto unlock; 1271a00cc7d9SMatthew Wilcox 12725fe653e9SMiaohe Lin touch_pud(vmf->vma, vmf->address, vmf->pud, write); 1273a00cc7d9SMatthew Wilcox unlock: 1274a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1275a00cc7d9SMatthew Wilcox } 1276a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1277a00cc7d9SMatthew Wilcox 12785db4f15cSYang Shi void huge_pmd_set_accessed(struct vm_fault *vmf) 1279a1dd450bSWill Deacon { 128020f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1281a1dd450bSWill Deacon 128282b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 1283a69e4717SMiaohe Lin if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) 1284a1dd450bSWill Deacon goto unlock; 1285a1dd450bSWill Deacon 1286a69e4717SMiaohe Lin touch_pmd(vmf->vma, vmf->address, vmf->pmd, write); 1287a1dd450bSWill Deacon 1288a1dd450bSWill Deacon unlock: 128982b0f8c3SJan Kara spin_unlock(vmf->ptl); 1290a1dd450bSWill Deacon } 1291a1dd450bSWill Deacon 12925db4f15cSYang Shi vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) 129371e3aac0SAndrea Arcangeli { 1294c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 129582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 12962fad3d14SMatthew Wilcox (Oracle) struct folio *folio; 12973917c802SKirill A. Shutemov struct page *page; 129882b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 12995db4f15cSYang Shi pmd_t orig_pmd = vmf->orig_pmd; 130071e3aac0SAndrea Arcangeli 130182b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 130281d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 13033917c802SKirill A. Shutemov 130493b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 13053917c802SKirill A. Shutemov goto fallback; 13063917c802SKirill A. Shutemov 130782b0f8c3SJan Kara spin_lock(vmf->ptl); 13083917c802SKirill A. Shutemov 13093917c802SKirill A. Shutemov if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13103917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13113917c802SKirill A. Shutemov return 0; 13123917c802SKirill A. Shutemov } 131371e3aac0SAndrea Arcangeli 131471e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 13152fad3d14SMatthew Wilcox (Oracle) folio = page_folio(page); 1316f6004e73SMiaohe Lin VM_BUG_ON_PAGE(!PageHead(page), page); 13173917c802SKirill A. Shutemov 13186c287605SDavid Hildenbrand /* Early check when only holding the PT lock. */ 13196c287605SDavid Hildenbrand if (PageAnonExclusive(page)) 13206c287605SDavid Hildenbrand goto reuse; 13216c287605SDavid Hildenbrand 13222fad3d14SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) { 13232fad3d14SMatthew Wilcox (Oracle) folio_get(folio); 1324ba3c4ce6SHuang Ying spin_unlock(vmf->ptl); 13252fad3d14SMatthew Wilcox (Oracle) folio_lock(folio); 1326ba3c4ce6SHuang Ying spin_lock(vmf->ptl); 1327ba3c4ce6SHuang Ying if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13283917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13292fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13302fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 13313917c802SKirill A. Shutemov return 0; 1332ba3c4ce6SHuang Ying } 13332fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 1334ba3c4ce6SHuang Ying } 13353917c802SKirill A. Shutemov 13366c287605SDavid Hildenbrand /* Recheck after temporarily dropping the PT lock. */ 13376c287605SDavid Hildenbrand if (PageAnonExclusive(page)) { 13382fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13396c287605SDavid Hildenbrand goto reuse; 13406c287605SDavid Hildenbrand } 13416c287605SDavid Hildenbrand 13423917c802SKirill A. Shutemov /* 13432fad3d14SMatthew Wilcox (Oracle) * See do_wp_page(): we can only reuse the folio exclusively if 13442fad3d14SMatthew Wilcox (Oracle) * there are no additional references. Note that we always drain 13451fec6890SMatthew Wilcox (Oracle) * the LRU cache immediately after adding a THP. 13463917c802SKirill A. Shutemov */ 13472fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) > 13482fad3d14SMatthew Wilcox (Oracle) 1 + folio_test_swapcache(folio) * folio_nr_pages(folio)) 13493bff7e3fSDavid Hildenbrand goto unlock_fallback; 13502fad3d14SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 13512fad3d14SMatthew Wilcox (Oracle) folio_free_swap(folio); 13522fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) == 1) { 135371e3aac0SAndrea Arcangeli pmd_t entry; 13546c54dc6cSDavid Hildenbrand 13556c54dc6cSDavid Hildenbrand page_move_anon_rmap(page, vma); 13562fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 13576c287605SDavid Hildenbrand reuse: 1358c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 1359c89357e2SDavid Hildenbrand spin_unlock(vmf->ptl); 1360c89357e2SDavid Hildenbrand return 0; 1361c89357e2SDavid Hildenbrand } 136271e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 1363f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 136482b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 136582b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 13663917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 1367cb8d8633SDavid Hildenbrand return 0; 136871e3aac0SAndrea Arcangeli } 13693917c802SKirill A. Shutemov 13703bff7e3fSDavid Hildenbrand unlock_fallback: 13712fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 137282b0f8c3SJan Kara spin_unlock(vmf->ptl); 13733917c802SKirill A. Shutemov fallback: 13743917c802SKirill A. Shutemov __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); 13753917c802SKirill A. Shutemov return VM_FAULT_FALLBACK; 137671e3aac0SAndrea Arcangeli } 137771e3aac0SAndrea Arcangeli 1378c27f479eSDavid Hildenbrand static inline bool can_change_pmd_writable(struct vm_area_struct *vma, 1379c27f479eSDavid Hildenbrand unsigned long addr, pmd_t pmd) 1380c27f479eSDavid Hildenbrand { 1381c27f479eSDavid Hildenbrand struct page *page; 1382c27f479eSDavid Hildenbrand 1383c27f479eSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) 1384c27f479eSDavid Hildenbrand return false; 1385c27f479eSDavid Hildenbrand 1386c27f479eSDavid Hildenbrand /* Don't touch entries that are not even readable (NUMA hinting). */ 1387c27f479eSDavid Hildenbrand if (pmd_protnone(pmd)) 1388c27f479eSDavid Hildenbrand return false; 1389c27f479eSDavid Hildenbrand 1390c27f479eSDavid Hildenbrand /* Do we need write faults for softdirty tracking? */ 1391c27f479eSDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 1392c27f479eSDavid Hildenbrand return false; 1393c27f479eSDavid Hildenbrand 1394c27f479eSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 1395c27f479eSDavid Hildenbrand if (userfaultfd_huge_pmd_wp(vma, pmd)) 1396c27f479eSDavid Hildenbrand return false; 1397c27f479eSDavid Hildenbrand 1398c27f479eSDavid Hildenbrand if (!(vma->vm_flags & VM_SHARED)) { 1399c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1400c27f479eSDavid Hildenbrand page = vm_normal_page_pmd(vma, addr, pmd); 1401c27f479eSDavid Hildenbrand return page && PageAnon(page) && PageAnonExclusive(page); 1402c27f479eSDavid Hildenbrand } 1403c27f479eSDavid Hildenbrand 1404c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1405c27f479eSDavid Hildenbrand return pmd_dirty(pmd); 1406c27f479eSDavid Hildenbrand } 1407c27f479eSDavid Hildenbrand 14085535be30SDavid Hildenbrand /* FOLL_FORCE can write to even unwritable PMDs in COW mappings. */ 14095535be30SDavid Hildenbrand static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, 14105535be30SDavid Hildenbrand struct vm_area_struct *vma, 14115535be30SDavid Hildenbrand unsigned int flags) 14128310d48bSKeno Fischer { 14135535be30SDavid Hildenbrand /* If the pmd is writable, we can write to the page. */ 14145535be30SDavid Hildenbrand if (pmd_write(pmd)) 14155535be30SDavid Hildenbrand return true; 14165535be30SDavid Hildenbrand 14175535be30SDavid Hildenbrand /* Maybe FOLL_FORCE is set to override it? */ 14185535be30SDavid Hildenbrand if (!(flags & FOLL_FORCE)) 14195535be30SDavid Hildenbrand return false; 14205535be30SDavid Hildenbrand 14215535be30SDavid Hildenbrand /* But FOLL_FORCE has no effect on shared mappings */ 14225535be30SDavid Hildenbrand if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED)) 14235535be30SDavid Hildenbrand return false; 14245535be30SDavid Hildenbrand 14255535be30SDavid Hildenbrand /* ... or read-only private ones */ 14265535be30SDavid Hildenbrand if (!(vma->vm_flags & VM_MAYWRITE)) 14275535be30SDavid Hildenbrand return false; 14285535be30SDavid Hildenbrand 14295535be30SDavid Hildenbrand /* ... or already writable ones that just need to take a write fault */ 14305535be30SDavid Hildenbrand if (vma->vm_flags & VM_WRITE) 14315535be30SDavid Hildenbrand return false; 14325535be30SDavid Hildenbrand 14335535be30SDavid Hildenbrand /* 14345535be30SDavid Hildenbrand * See can_change_pte_writable(): we broke COW and could map the page 14355535be30SDavid Hildenbrand * writable if we have an exclusive anonymous page ... 14365535be30SDavid Hildenbrand */ 14375535be30SDavid Hildenbrand if (!page || !PageAnon(page) || !PageAnonExclusive(page)) 14385535be30SDavid Hildenbrand return false; 14395535be30SDavid Hildenbrand 14405535be30SDavid Hildenbrand /* ... and a write-fault isn't required for other reasons. */ 14415535be30SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 14425535be30SDavid Hildenbrand return false; 14435535be30SDavid Hildenbrand return !userfaultfd_huge_pmd_wp(vma, pmd); 14448310d48bSKeno Fischer } 14458310d48bSKeno Fischer 1446b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 144771e3aac0SAndrea Arcangeli unsigned long addr, 144871e3aac0SAndrea Arcangeli pmd_t *pmd, 144971e3aac0SAndrea Arcangeli unsigned int flags) 145071e3aac0SAndrea Arcangeli { 1451b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 14525535be30SDavid Hildenbrand struct page *page; 14530f089235SLogan Gunthorpe int ret; 145471e3aac0SAndrea Arcangeli 1455c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 145671e3aac0SAndrea Arcangeli 14575535be30SDavid Hildenbrand page = pmd_page(*pmd); 14585535be30SDavid Hildenbrand VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 14595535be30SDavid Hildenbrand 14605535be30SDavid Hildenbrand if ((flags & FOLL_WRITE) && 14615535be30SDavid Hildenbrand !can_follow_write_pmd(*pmd, page, vma, flags)) 14625535be30SDavid Hildenbrand return NULL; 146371e3aac0SAndrea Arcangeli 146485facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 146585facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 146685facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 146785facf25SKirill A. Shutemov 1468d74943a2SDavid Hildenbrand if (pmd_protnone(*pmd) && !gup_can_follow_protnone(vma, flags)) 14695535be30SDavid Hildenbrand return NULL; 14703faa52c0SJohn Hubbard 147184209e87SDavid Hildenbrand if (!pmd_write(*pmd) && gup_must_unshare(vma, flags, page)) 1472a7f22660SDavid Hildenbrand return ERR_PTR(-EMLINK); 1473a7f22660SDavid Hildenbrand 1474b6a2619cSDavid Hildenbrand VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && 1475b6a2619cSDavid Hildenbrand !PageAnonExclusive(page), page); 1476b6a2619cSDavid Hildenbrand 14770f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 14780f089235SLogan Gunthorpe if (ret) 14790f089235SLogan Gunthorpe return ERR_PTR(ret); 14803faa52c0SJohn Hubbard 14813565fce3SDan Williams if (flags & FOLL_TOUCH) 1482a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 14833faa52c0SJohn Hubbard 148471e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1485ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 148671e3aac0SAndrea Arcangeli 148771e3aac0SAndrea Arcangeli return page; 148871e3aac0SAndrea Arcangeli } 148971e3aac0SAndrea Arcangeli 1490d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 14915db4f15cSYang Shi vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) 1492d10e63f2SMel Gorman { 149382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1494c5b5a3ddSYang Shi pmd_t oldpmd = vmf->orig_pmd; 1495c5b5a3ddSYang Shi pmd_t pmd; 1496b32967ffSMel Gorman struct page *page; 149782b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 1498c5b5a3ddSYang Shi int page_nid = NUMA_NO_NODE; 149933024536SHuang Ying int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); 15006a56ccbcSDavid Hildenbrand bool migrated = false, writable = false; 15016688cc05SPeter Zijlstra int flags = 0; 1502d10e63f2SMel Gorman 150382b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1504c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 150582b0f8c3SJan Kara spin_unlock(vmf->ptl); 1506de466bd6SMel Gorman goto out; 1507de466bd6SMel Gorman } 1508de466bd6SMel Gorman 1509c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 15106a56ccbcSDavid Hildenbrand 15116a56ccbcSDavid Hildenbrand /* 15126a56ccbcSDavid Hildenbrand * Detect now whether the PMD could be writable; this information 15136a56ccbcSDavid Hildenbrand * is only valid while holding the PT lock. 15146a56ccbcSDavid Hildenbrand */ 15156a56ccbcSDavid Hildenbrand writable = pmd_write(pmd); 15166a56ccbcSDavid Hildenbrand if (!writable && vma_wants_manual_pte_write_upgrade(vma) && 15176a56ccbcSDavid Hildenbrand can_change_pmd_writable(vma, vmf->address, pmd)) 15186a56ccbcSDavid Hildenbrand writable = true; 15196a56ccbcSDavid Hildenbrand 1520c5b5a3ddSYang Shi page = vm_normal_page_pmd(vma, haddr, pmd); 1521c5b5a3ddSYang Shi if (!page) 1522c5b5a3ddSYang Shi goto out_map; 1523c5b5a3ddSYang Shi 1524c5b5a3ddSYang Shi /* See similar comment in do_numa_page for explanation */ 15256a56ccbcSDavid Hildenbrand if (!writable) 1526c5b5a3ddSYang Shi flags |= TNF_NO_GROUP; 1527c5b5a3ddSYang Shi 1528c5b5a3ddSYang Shi page_nid = page_to_nid(page); 152933024536SHuang Ying /* 153033024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 153133024536SHuang Ying * to record page access time. So use default value. 153233024536SHuang Ying */ 153333024536SHuang Ying if (node_is_toptier(page_nid)) 1534c5b5a3ddSYang Shi last_cpupid = page_cpupid_last(page); 1535c5b5a3ddSYang Shi target_nid = numa_migrate_prep(page, vma, haddr, page_nid, 1536c5b5a3ddSYang Shi &flags); 1537c5b5a3ddSYang Shi 1538c5b5a3ddSYang Shi if (target_nid == NUMA_NO_NODE) { 1539c5b5a3ddSYang Shi put_page(page); 1540c5b5a3ddSYang Shi goto out_map; 1541c5b5a3ddSYang Shi } 1542c5b5a3ddSYang Shi 154382b0f8c3SJan Kara spin_unlock(vmf->ptl); 15446a56ccbcSDavid Hildenbrand writable = false; 15458b1b436dSPeter Zijlstra 1546c5b5a3ddSYang Shi migrated = migrate_misplaced_page(page, vma, target_nid); 15476688cc05SPeter Zijlstra if (migrated) { 15486688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 15498191acbdSMel Gorman page_nid = target_nid; 1550c5b5a3ddSYang Shi } else { 1551074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1552c5b5a3ddSYang Shi vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1553c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 155482b0f8c3SJan Kara spin_unlock(vmf->ptl); 1555c5b5a3ddSYang Shi goto out; 1556c5b5a3ddSYang Shi } 1557c5b5a3ddSYang Shi goto out_map; 1558c5b5a3ddSYang Shi } 1559b8916634SMel Gorman 1560b8916634SMel Gorman out: 156198fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 156282b0f8c3SJan Kara task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, 15639a8b300fSAneesh Kumar K.V flags); 15648191acbdSMel Gorman 1565d10e63f2SMel Gorman return 0; 1566c5b5a3ddSYang Shi 1567c5b5a3ddSYang Shi out_map: 1568c5b5a3ddSYang Shi /* Restore the PMD */ 1569c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 1570c5b5a3ddSYang Shi pmd = pmd_mkyoung(pmd); 15716a56ccbcSDavid Hildenbrand if (writable) 1572c5b5a3ddSYang Shi pmd = pmd_mkwrite(pmd); 1573c5b5a3ddSYang Shi set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 1574c5b5a3ddSYang Shi update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1575c5b5a3ddSYang Shi spin_unlock(vmf->ptl); 1576c5b5a3ddSYang Shi goto out; 1577d10e63f2SMel Gorman } 1578d10e63f2SMel Gorman 1579319904adSHuang Ying /* 1580319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1581319904adSHuang Ying * Otherwise, return false. 1582319904adSHuang Ying */ 1583319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1584b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1585b8d3c4c3SMinchan Kim { 1586b8d3c4c3SMinchan Kim spinlock_t *ptl; 1587b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1588fc986a38SKefeng Wang struct folio *folio; 1589b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1590319904adSHuang Ying bool ret = false; 1591b8d3c4c3SMinchan Kim 1592ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 159307e32661SAneesh Kumar K.V 1594b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1595b6ec57f4SKirill A. Shutemov if (!ptl) 159625eedabeSLinus Torvalds goto out_unlocked; 1597b8d3c4c3SMinchan Kim 1598b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1599319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1600b8d3c4c3SMinchan Kim goto out; 1601b8d3c4c3SMinchan Kim 160284c3fc4eSZi Yan if (unlikely(!pmd_present(orig_pmd))) { 160384c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 160484c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 160584c3fc4eSZi Yan goto out; 160684c3fc4eSZi Yan } 160784c3fc4eSZi Yan 1608fc986a38SKefeng Wang folio = pfn_folio(pmd_pfn(orig_pmd)); 1609b8d3c4c3SMinchan Kim /* 1610fc986a38SKefeng Wang * If other processes are mapping this folio, we couldn't discard 1611fc986a38SKefeng Wang * the folio unless they all do MADV_FREE so let's skip the folio. 1612b8d3c4c3SMinchan Kim */ 1613fc986a38SKefeng Wang if (folio_mapcount(folio) != 1) 1614b8d3c4c3SMinchan Kim goto out; 1615b8d3c4c3SMinchan Kim 1616fc986a38SKefeng Wang if (!folio_trylock(folio)) 1617b8d3c4c3SMinchan Kim goto out; 1618b8d3c4c3SMinchan Kim 1619b8d3c4c3SMinchan Kim /* 1620b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1621b8d3c4c3SMinchan Kim * will deactivate only them. 1622b8d3c4c3SMinchan Kim */ 1623b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1624fc986a38SKefeng Wang folio_get(folio); 1625b8d3c4c3SMinchan Kim spin_unlock(ptl); 1626fc986a38SKefeng Wang split_folio(folio); 1627fc986a38SKefeng Wang folio_unlock(folio); 1628fc986a38SKefeng Wang folio_put(folio); 1629b8d3c4c3SMinchan Kim goto out_unlocked; 1630b8d3c4c3SMinchan Kim } 1631b8d3c4c3SMinchan Kim 1632fc986a38SKefeng Wang if (folio_test_dirty(folio)) 1633fc986a38SKefeng Wang folio_clear_dirty(folio); 1634fc986a38SKefeng Wang folio_unlock(folio); 1635b8d3c4c3SMinchan Kim 1636b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 163758ceeb6bSKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1638b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1639b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1640b8d3c4c3SMinchan Kim 1641b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1642b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1643b8d3c4c3SMinchan Kim } 1644802a3a92SShaohua Li 16456a6fe9ebSKefeng Wang folio_mark_lazyfree(folio); 1646319904adSHuang Ying ret = true; 1647b8d3c4c3SMinchan Kim out: 1648b8d3c4c3SMinchan Kim spin_unlock(ptl); 1649b8d3c4c3SMinchan Kim out_unlocked: 1650b8d3c4c3SMinchan Kim return ret; 1651b8d3c4c3SMinchan Kim } 1652b8d3c4c3SMinchan Kim 1653953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1654953c66c2SAneesh Kumar K.V { 1655953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1656953c66c2SAneesh Kumar K.V 1657953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1658953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1659c4812909SKirill A. Shutemov mm_dec_nr_ptes(mm); 1660953c66c2SAneesh Kumar K.V } 1661953c66c2SAneesh Kumar K.V 166271e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1663f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 166471e3aac0SAndrea Arcangeli { 1665f5c8ad47SDavid Miller pmd_t orig_pmd; 1666da146769SKirill A. Shutemov spinlock_t *ptl; 1667da146769SKirill A. Shutemov 1668ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 166907e32661SAneesh Kumar K.V 1670b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1671b6ec57f4SKirill A. Shutemov if (!ptl) 1672da146769SKirill A. Shutemov return 0; 1673a6bf2bb0SAneesh Kumar K.V /* 1674a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 16758809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1676a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1677a6bf2bb0SAneesh Kumar K.V * operations. 1678a6bf2bb0SAneesh Kumar K.V */ 167993a98695SAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, 1680fcbe08d6SMartin Schwidefsky tlb->fullmm); 1681f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 16822484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 16833b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) 16843b6521f5SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 16854897c765SMatthew Wilcox spin_unlock(ptl); 1686da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1687c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1688bf929152SKirill A. Shutemov spin_unlock(ptl); 1689479f0abbSKirill A. Shutemov } else { 1690616b8371SZi Yan struct page *page = NULL; 1691616b8371SZi Yan int flush_needed = 1; 1692616b8371SZi Yan 1693616b8371SZi Yan if (pmd_present(orig_pmd)) { 1694616b8371SZi Yan page = pmd_page(orig_pmd); 1695cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 1696309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1697309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1698616b8371SZi Yan } else if (thp_migration_supported()) { 1699616b8371SZi Yan swp_entry_t entry; 1700616b8371SZi Yan 1701616b8371SZi Yan VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); 1702616b8371SZi Yan entry = pmd_to_swp_entry(orig_pmd); 1703af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1704616b8371SZi Yan flush_needed = 0; 1705616b8371SZi Yan } else 1706616b8371SZi Yan WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); 1707616b8371SZi Yan 1708b5072380SKirill A. Shutemov if (PageAnon(page)) { 1709c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1710b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1711b5072380SKirill A. Shutemov } else { 1712953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1713953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1714fadae295SYang Shi add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); 1715b5072380SKirill A. Shutemov } 1716616b8371SZi Yan 1717bf929152SKirill A. Shutemov spin_unlock(ptl); 1718616b8371SZi Yan if (flush_needed) 1719e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1720479f0abbSKirill A. Shutemov } 1721da146769SKirill A. Shutemov return 1; 172271e3aac0SAndrea Arcangeli } 172371e3aac0SAndrea Arcangeli 17241dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 17251dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 17261dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 17271dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 17281dd38b6cSAneesh Kumar K.V { 17291dd38b6cSAneesh Kumar K.V /* 17301dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 17311dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 17321dd38b6cSAneesh Kumar K.V * 17331dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 17341dd38b6cSAneesh Kumar K.V */ 17351dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 17361dd38b6cSAneesh Kumar K.V } 17371dd38b6cSAneesh Kumar K.V #endif 17381dd38b6cSAneesh Kumar K.V 1739ab6e3d09SNaoya Horiguchi static pmd_t move_soft_dirty_pmd(pmd_t pmd) 1740ab6e3d09SNaoya Horiguchi { 1741ab6e3d09SNaoya Horiguchi #ifdef CONFIG_MEM_SOFT_DIRTY 1742ab6e3d09SNaoya Horiguchi if (unlikely(is_pmd_migration_entry(pmd))) 1743ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 1744ab6e3d09SNaoya Horiguchi else if (pmd_present(pmd)) 1745ab6e3d09SNaoya Horiguchi pmd = pmd_mksoft_dirty(pmd); 1746ab6e3d09SNaoya Horiguchi #endif 1747ab6e3d09SNaoya Horiguchi return pmd; 1748ab6e3d09SNaoya Horiguchi } 1749ab6e3d09SNaoya Horiguchi 1750bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 1751b8aa9d9dSWei Yang unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) 175237a1c49aSAndrea Arcangeli { 1753bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 175437a1c49aSAndrea Arcangeli pmd_t pmd; 175537a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 17565d190420SAaron Lu bool force_flush = false; 175737a1c49aSAndrea Arcangeli 175837a1c49aSAndrea Arcangeli /* 175937a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 1760a5be621eSHugh Dickins * should have released it; but move_page_tables() might have already 1761a5be621eSHugh Dickins * inserted a page table, if racing against shmem/file collapse. 176237a1c49aSAndrea Arcangeli */ 1763a5be621eSHugh Dickins if (!pmd_none(*new_pmd)) { 176437a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 17654b471e88SKirill A. Shutemov return false; 176637a1c49aSAndrea Arcangeli } 176737a1c49aSAndrea Arcangeli 1768bf929152SKirill A. Shutemov /* 1769bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1770c1e8d7c6SMichel Lespinasse * ptlocks because exclusive mmap_lock prevents deadlock. 1771bf929152SKirill A. Shutemov */ 1772b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1773b6ec57f4SKirill A. Shutemov if (old_ptl) { 1774bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1775bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1776bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 17778809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1778eb66ae03SLinus Torvalds if (pmd_present(pmd)) 1779a2ce2666SAaron Lu force_flush = true; 178037a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 17813592806cSKirill A. Shutemov 17821dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1783b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 17843592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 17853592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 17863592806cSKirill A. Shutemov } 1787ab6e3d09SNaoya Horiguchi pmd = move_soft_dirty_pmd(pmd); 1788ab6e3d09SNaoya Horiguchi set_pmd_at(mm, new_addr, new_pmd, pmd); 17895d190420SAaron Lu if (force_flush) 17907c38f181SMiaohe Lin flush_pmd_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 1791eb66ae03SLinus Torvalds if (new_ptl != old_ptl) 1792eb66ae03SLinus Torvalds spin_unlock(new_ptl); 1793bf929152SKirill A. Shutemov spin_unlock(old_ptl); 17944b471e88SKirill A. Shutemov return true; 179537a1c49aSAndrea Arcangeli } 17964b471e88SKirill A. Shutemov return false; 179737a1c49aSAndrea Arcangeli } 179837a1c49aSAndrea Arcangeli 1799f123d74aSMel Gorman /* 1800f123d74aSMel Gorman * Returns 1801f123d74aSMel Gorman * - 0 if PMD could not be locked 1802f0953a1bSIngo Molnar * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary 1803e346e668SYang Shi * or if prot_numa but THP migration is not supported 1804f0953a1bSIngo Molnar * - HPAGE_PMD_NR if protections changed and TLB flush necessary 1805f123d74aSMel Gorman */ 18064a18419fSNadav Amit int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 18074a18419fSNadav Amit pmd_t *pmd, unsigned long addr, pgprot_t newprot, 18084a18419fSNadav Amit unsigned long cp_flags) 1809cd7548abSJohannes Weiner { 1810cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1811bf929152SKirill A. Shutemov spinlock_t *ptl; 1812c9fe6656SNadav Amit pmd_t oldpmd, entry; 181358705444SPeter Xu bool prot_numa = cp_flags & MM_CP_PROT_NUMA; 1814292924b2SPeter Xu bool uffd_wp = cp_flags & MM_CP_UFFD_WP; 1815292924b2SPeter Xu bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; 18166a56ccbcSDavid Hildenbrand int ret = 1; 1817cd7548abSJohannes Weiner 18184a18419fSNadav Amit tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 18194a18419fSNadav Amit 1820e346e668SYang Shi if (prot_numa && !thp_migration_supported()) 1821e346e668SYang Shi return 1; 1822e346e668SYang Shi 1823b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 18240a85e51dSKirill A. Shutemov if (!ptl) 18250a85e51dSKirill A. Shutemov return 0; 18260a85e51dSKirill A. Shutemov 182784c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 182884c3fc4eSZi Yan if (is_swap_pmd(*pmd)) { 182984c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(*pmd); 18306c287605SDavid Hildenbrand struct page *page = pfn_swap_entry_to_page(entry); 183124bf08c4SDavid Hildenbrand pmd_t newpmd; 183284c3fc4eSZi Yan 183384c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd)); 18344dd845b5SAlistair Popple if (is_writable_migration_entry(entry)) { 183584c3fc4eSZi Yan /* 183684c3fc4eSZi Yan * A protection check is difficult so 183784c3fc4eSZi Yan * just be safe and disable write 183884c3fc4eSZi Yan */ 18396c287605SDavid Hildenbrand if (PageAnon(page)) 18406c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(swp_offset(entry)); 18416c287605SDavid Hildenbrand else 18426c287605SDavid Hildenbrand entry = make_readable_migration_entry(swp_offset(entry)); 184384c3fc4eSZi Yan newpmd = swp_entry_to_pmd(entry); 1844ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pmd)) 1845ab6e3d09SNaoya Horiguchi newpmd = pmd_swp_mksoft_dirty(newpmd); 184624bf08c4SDavid Hildenbrand } else { 184724bf08c4SDavid Hildenbrand newpmd = *pmd; 184884c3fc4eSZi Yan } 184924bf08c4SDavid Hildenbrand 185024bf08c4SDavid Hildenbrand if (uffd_wp) 185124bf08c4SDavid Hildenbrand newpmd = pmd_swp_mkuffd_wp(newpmd); 185224bf08c4SDavid Hildenbrand else if (uffd_wp_resolve) 185324bf08c4SDavid Hildenbrand newpmd = pmd_swp_clear_uffd_wp(newpmd); 185424bf08c4SDavid Hildenbrand if (!pmd_same(*pmd, newpmd)) 185524bf08c4SDavid Hildenbrand set_pmd_at(mm, addr, pmd, newpmd); 185684c3fc4eSZi Yan goto unlock; 185784c3fc4eSZi Yan } 185884c3fc4eSZi Yan #endif 185984c3fc4eSZi Yan 1860a1a3a2fcSHuang Ying if (prot_numa) { 1861a1a3a2fcSHuang Ying struct page *page; 186233024536SHuang Ying bool toptier; 1863e944fd67SMel Gorman /* 1864e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1865e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1866e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1867e944fd67SMel Gorman */ 1868a1a3a2fcSHuang Ying if (is_huge_zero_pmd(*pmd)) 18690a85e51dSKirill A. Shutemov goto unlock; 1870e944fd67SMel Gorman 1871a1a3a2fcSHuang Ying if (pmd_protnone(*pmd)) 18720a85e51dSKirill A. Shutemov goto unlock; 18730a85e51dSKirill A. Shutemov 1874a1a3a2fcSHuang Ying page = pmd_page(*pmd); 187533024536SHuang Ying toptier = node_is_toptier(page_to_nid(page)); 1876a1a3a2fcSHuang Ying /* 1877a1a3a2fcSHuang Ying * Skip scanning top tier node if normal numa 1878a1a3a2fcSHuang Ying * balancing is disabled 1879a1a3a2fcSHuang Ying */ 1880a1a3a2fcSHuang Ying if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && 188133024536SHuang Ying toptier) 1882a1a3a2fcSHuang Ying goto unlock; 188333024536SHuang Ying 188433024536SHuang Ying if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && 188533024536SHuang Ying !toptier) 188633024536SHuang Ying xchg_page_access_time(page, jiffies_to_msecs(jiffies)); 1887a1a3a2fcSHuang Ying } 1888ced10803SKirill A. Shutemov /* 18893e4e28c5SMichel Lespinasse * In case prot_numa, we are under mmap_read_lock(mm). It's critical 1890ced10803SKirill A. Shutemov * to not clear pmd intermittently to avoid race with MADV_DONTNEED 18913e4e28c5SMichel Lespinasse * which is also under mmap_read_lock(mm): 1892ced10803SKirill A. Shutemov * 1893ced10803SKirill A. Shutemov * CPU0: CPU1: 1894ced10803SKirill A. Shutemov * change_huge_pmd(prot_numa=1) 1895ced10803SKirill A. Shutemov * pmdp_huge_get_and_clear_notify() 1896ced10803SKirill A. Shutemov * madvise_dontneed() 1897ced10803SKirill A. Shutemov * zap_pmd_range() 1898ced10803SKirill A. Shutemov * pmd_trans_huge(*pmd) == 0 (without ptl) 1899ced10803SKirill A. Shutemov * // skip the pmd 1900ced10803SKirill A. Shutemov * set_pmd_at(); 1901ced10803SKirill A. Shutemov * // pmd is re-established 1902ced10803SKirill A. Shutemov * 1903ced10803SKirill A. Shutemov * The race makes MADV_DONTNEED miss the huge pmd and don't clear it 1904ced10803SKirill A. Shutemov * which may break userspace. 1905ced10803SKirill A. Shutemov * 19064f831457SNadav Amit * pmdp_invalidate_ad() is required to make sure we don't miss 1907ced10803SKirill A. Shutemov * dirty/young flags set by hardware. 1908ced10803SKirill A. Shutemov */ 19094f831457SNadav Amit oldpmd = pmdp_invalidate_ad(vma, addr, pmd); 1910ced10803SKirill A. Shutemov 1911c9fe6656SNadav Amit entry = pmd_modify(oldpmd, newprot); 1912f1eb1bacSPeter Xu if (uffd_wp) 1913292924b2SPeter Xu entry = pmd_mkuffd_wp(entry); 1914f1eb1bacSPeter Xu else if (uffd_wp_resolve) 1915292924b2SPeter Xu /* 1916292924b2SPeter Xu * Leave the write bit to be handled by PF interrupt 1917292924b2SPeter Xu * handler, then things like COW could be properly 1918292924b2SPeter Xu * handled. 1919292924b2SPeter Xu */ 1920292924b2SPeter Xu entry = pmd_clear_uffd_wp(entry); 1921c27f479eSDavid Hildenbrand 1922c27f479eSDavid Hildenbrand /* See change_pte_range(). */ 1923c27f479eSDavid Hildenbrand if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && !pmd_write(entry) && 1924c27f479eSDavid Hildenbrand can_change_pmd_writable(vma, addr, entry)) 1925c27f479eSDavid Hildenbrand entry = pmd_mkwrite(entry); 1926c27f479eSDavid Hildenbrand 1927f123d74aSMel Gorman ret = HPAGE_PMD_NR; 192856eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 19294a18419fSNadav Amit 1930c9fe6656SNadav Amit if (huge_pmd_needs_flush(oldpmd, entry)) 19314a18419fSNadav Amit tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); 19320a85e51dSKirill A. Shutemov unlock: 1933bf929152SKirill A. Shutemov spin_unlock(ptl); 1934cd7548abSJohannes Weiner return ret; 1935cd7548abSJohannes Weiner } 1936cd7548abSJohannes Weiner 1937025c5b24SNaoya Horiguchi /* 19388f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 1939025c5b24SNaoya Horiguchi * 19408f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 19418f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 1942025c5b24SNaoya Horiguchi */ 1943b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1944025c5b24SNaoya Horiguchi { 1945b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 1946b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 194784c3fc4eSZi Yan if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || 194884c3fc4eSZi Yan pmd_devmap(*pmd))) 1949b6ec57f4SKirill A. Shutemov return ptl; 1950b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 1951b6ec57f4SKirill A. Shutemov return NULL; 1952025c5b24SNaoya Horiguchi } 1953025c5b24SNaoya Horiguchi 1954a00cc7d9SMatthew Wilcox /* 1955d965e390SMiaohe Lin * Returns page table lock pointer if a given pud maps a thp, NULL otherwise. 1956a00cc7d9SMatthew Wilcox * 1957d965e390SMiaohe Lin * Note that if it returns page table lock pointer, this routine returns without 1958d965e390SMiaohe Lin * unlocking page table lock. So callers must unlock it. 1959a00cc7d9SMatthew Wilcox */ 1960a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 1961a00cc7d9SMatthew Wilcox { 1962a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1963a00cc7d9SMatthew Wilcox 1964a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 1965a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 1966a00cc7d9SMatthew Wilcox return ptl; 1967a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1968a00cc7d9SMatthew Wilcox return NULL; 1969a00cc7d9SMatthew Wilcox } 1970a00cc7d9SMatthew Wilcox 1971a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1972a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 1973a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 1974a00cc7d9SMatthew Wilcox { 1975a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1976a00cc7d9SMatthew Wilcox 1977a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 1978a00cc7d9SMatthew Wilcox if (!ptl) 1979a00cc7d9SMatthew Wilcox return 0; 198074929079SMiaohe Lin 1981f32928abSAneesh Kumar K.V pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm); 1982a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 19832484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 1984a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1985a00cc7d9SMatthew Wilcox /* No zero page support yet */ 1986a00cc7d9SMatthew Wilcox } else { 1987a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 1988a00cc7d9SMatthew Wilcox BUG(); 1989a00cc7d9SMatthew Wilcox } 1990a00cc7d9SMatthew Wilcox return 1; 1991a00cc7d9SMatthew Wilcox } 1992a00cc7d9SMatthew Wilcox 1993a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 1994a00cc7d9SMatthew Wilcox unsigned long haddr) 1995a00cc7d9SMatthew Wilcox { 1996a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 1997a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 1998a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 1999a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 2000a00cc7d9SMatthew Wilcox 2001ce9311cfSYisheng Xie count_vm_event(THP_SPLIT_PUD); 2002a00cc7d9SMatthew Wilcox 2003ec8832d0SAlistair Popple pudp_huge_clear_flush(vma, haddr, pud); 2004a00cc7d9SMatthew Wilcox } 2005a00cc7d9SMatthew Wilcox 2006a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 2007a00cc7d9SMatthew Wilcox unsigned long address) 2008a00cc7d9SMatthew Wilcox { 2009a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2010ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2011a00cc7d9SMatthew Wilcox 20127d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 20136f4f13e8SJérôme Glisse address & HPAGE_PUD_MASK, 2014ac46d4f3SJérôme Glisse (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); 2015ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2016ac46d4f3SJérôme Glisse ptl = pud_lock(vma->vm_mm, pud); 2017a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 2018a00cc7d9SMatthew Wilcox goto out; 2019ac46d4f3SJérôme Glisse __split_huge_pud_locked(vma, pud, range.start); 2020a00cc7d9SMatthew Wilcox 2021a00cc7d9SMatthew Wilcox out: 2022a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2023ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 2024a00cc7d9SMatthew Wilcox } 2025a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 2026a00cc7d9SMatthew Wilcox 2027eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2028eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2029eef1b3baSKirill A. Shutemov { 2030eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2031eef1b3baSKirill A. Shutemov pgtable_t pgtable; 203242b2af2cSDavid Hildenbrand pmd_t _pmd, old_pmd; 2033c9c1ee20SHugh Dickins unsigned long addr; 2034c9c1ee20SHugh Dickins pte_t *pte; 2035eef1b3baSKirill A. Shutemov int i; 2036eef1b3baSKirill A. Shutemov 20370f10851eSJérôme Glisse /* 20380f10851eSJérôme Glisse * Leave pmd empty until pte is filled note that it is fine to delay 20390f10851eSJérôme Glisse * notification until mmu_notifier_invalidate_range_end() as we are 20400f10851eSJérôme Glisse * replacing a zero pmd write protected page with a zero pte write 20410f10851eSJérôme Glisse * protected page. 20420f10851eSJérôme Glisse * 2043ee65728eSMike Rapoport * See Documentation/mm/mmu_notifier.rst 20440f10851eSJérôme Glisse */ 204542b2af2cSDavid Hildenbrand old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); 2046eef1b3baSKirill A. Shutemov 2047eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2048eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2049eef1b3baSKirill A. Shutemov 2050c9c1ee20SHugh Dickins pte = pte_offset_map(&_pmd, haddr); 2051c9c1ee20SHugh Dickins VM_BUG_ON(!pte); 2052c9c1ee20SHugh Dickins for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2053c9c1ee20SHugh Dickins pte_t entry; 2054c9c1ee20SHugh Dickins 2055c9c1ee20SHugh Dickins entry = pfn_pte(my_zero_pfn(addr), vma->vm_page_prot); 2056eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 205742b2af2cSDavid Hildenbrand if (pmd_uffd_wp(old_pmd)) 205842b2af2cSDavid Hildenbrand entry = pte_mkuffd_wp(entry); 2059c33c7948SRyan Roberts VM_BUG_ON(!pte_none(ptep_get(pte))); 2060c9c1ee20SHugh Dickins set_pte_at(mm, addr, pte, entry); 2061c9c1ee20SHugh Dickins pte++; 2062eef1b3baSKirill A. Shutemov } 2063c9c1ee20SHugh Dickins pte_unmap(pte - 1); 2064eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2065eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2066eef1b3baSKirill A. Shutemov } 2067eef1b3baSKirill A. Shutemov 2068eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 2069ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 2070eef1b3baSKirill A. Shutemov { 2071eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2072eef1b3baSKirill A. Shutemov struct page *page; 2073eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2074423ac9afSAneesh Kumar K.V pmd_t old_pmd, _pmd; 2075292924b2SPeter Xu bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; 20760ccf7f16SPeter Xu bool anon_exclusive = false, dirty = false; 20772ac015e2SKirill A. Shutemov unsigned long addr; 2078c9c1ee20SHugh Dickins pte_t *pte; 2079eef1b3baSKirill A. Shutemov int i; 2080eef1b3baSKirill A. Shutemov 2081eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 2082eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2083eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 208484c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) 208584c3fc4eSZi Yan && !pmd_devmap(*pmd)); 2086eef1b3baSKirill A. Shutemov 2087eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 2088eef1b3baSKirill A. Shutemov 2089d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 2090ec8832d0SAlistair Popple old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); 2091953c66c2SAneesh Kumar K.V /* 2092953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 2093953c66c2SAneesh Kumar K.V * just go ahead and zap it 2094953c66c2SAneesh Kumar K.V */ 2095953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 2096953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 20972484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) 2098d21b9e57SKirill A. Shutemov return; 209999fa8a48SHugh Dickins if (unlikely(is_pmd_migration_entry(old_pmd))) { 210099fa8a48SHugh Dickins swp_entry_t entry; 210199fa8a48SHugh Dickins 210299fa8a48SHugh Dickins entry = pmd_to_swp_entry(old_pmd); 2103af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 210499fa8a48SHugh Dickins } else { 210599fa8a48SHugh Dickins page = pmd_page(old_pmd); 210699fa8a48SHugh Dickins if (!PageDirty(page) && pmd_dirty(old_pmd)) 2107e1f1b157SHugh Dickins set_page_dirty(page); 210899fa8a48SHugh Dickins if (!PageReferenced(page) && pmd_young(old_pmd)) 2109d21b9e57SKirill A. Shutemov SetPageReferenced(page); 2110cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 2111d21b9e57SKirill A. Shutemov put_page(page); 211299fa8a48SHugh Dickins } 2113fadae295SYang Shi add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); 2114eef1b3baSKirill A. Shutemov return; 211599fa8a48SHugh Dickins } 211699fa8a48SHugh Dickins 21173b77e8c8SHugh Dickins if (is_huge_zero_pmd(*pmd)) { 21184645b9feSJérôme Glisse /* 21194645b9feSJérôme Glisse * FIXME: Do we want to invalidate secondary mmu by calling 21201af5a810SAlistair Popple * mmu_notifier_arch_invalidate_secondary_tlbs() see comments below 21211af5a810SAlistair Popple * inside __split_huge_pmd() ? 21224645b9feSJérôme Glisse * 21234645b9feSJérôme Glisse * We are going from a zero huge page write protected to zero 21244645b9feSJérôme Glisse * small page also write protected so it does not seems useful 21254645b9feSJérôme Glisse * to invalidate secondary mmu at this time. 21264645b9feSJérôme Glisse */ 2127eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 2128eef1b3baSKirill A. Shutemov } 2129eef1b3baSKirill A. Shutemov 2130423ac9afSAneesh Kumar K.V /* 2131423ac9afSAneesh Kumar K.V * Up to this point the pmd is present and huge and userland has the 2132423ac9afSAneesh Kumar K.V * whole access to the hugepage during the split (which happens in 2133423ac9afSAneesh Kumar K.V * place). If we overwrite the pmd with the not-huge version pointing 2134423ac9afSAneesh Kumar K.V * to the pte here (which of course we could if all CPUs were bug 2135423ac9afSAneesh Kumar K.V * free), userland could trigger a small page size TLB miss on the 2136423ac9afSAneesh Kumar K.V * small sized TLB while the hugepage TLB entry is still established in 2137423ac9afSAneesh Kumar K.V * the huge TLB. Some CPU doesn't like that. 213842742d9bSAlexander A. Klimov * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum 213942742d9bSAlexander A. Klimov * 383 on page 105. Intel should be safe but is also warns that it's 2140423ac9afSAneesh Kumar K.V * only safe if the permission and cache attributes of the two entries 2141423ac9afSAneesh Kumar K.V * loaded in the two TLB is identical (which should be the case here). 2142423ac9afSAneesh Kumar K.V * But it is generally safer to never allow small and huge TLB entries 2143423ac9afSAneesh Kumar K.V * for the same virtual address to be loaded simultaneously. So instead 2144423ac9afSAneesh Kumar K.V * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2145423ac9afSAneesh Kumar K.V * current pmd notpresent (atomically because here the pmd_trans_huge 2146423ac9afSAneesh Kumar K.V * must remain set at all times on the pmd until the split is complete 2147423ac9afSAneesh Kumar K.V * for this pmd), then we flush the SMP TLB and finally we write the 2148423ac9afSAneesh Kumar K.V * non-huge version of the pmd entry with pmd_populate. 2149423ac9afSAneesh Kumar K.V */ 2150423ac9afSAneesh Kumar K.V old_pmd = pmdp_invalidate(vma, haddr, pmd); 2151423ac9afSAneesh Kumar K.V 2152423ac9afSAneesh Kumar K.V pmd_migration = is_pmd_migration_entry(old_pmd); 21532e83ee1dSPeter Xu if (unlikely(pmd_migration)) { 215484c3fc4eSZi Yan swp_entry_t entry; 215584c3fc4eSZi Yan 2156423ac9afSAneesh Kumar K.V entry = pmd_to_swp_entry(old_pmd); 2157af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 21584dd845b5SAlistair Popple write = is_writable_migration_entry(entry); 21596c287605SDavid Hildenbrand if (PageAnon(page)) 21606c287605SDavid Hildenbrand anon_exclusive = is_readable_exclusive_migration_entry(entry); 21612e346877SPeter Xu young = is_migration_entry_young(entry); 21622e346877SPeter Xu dirty = is_migration_entry_dirty(entry); 21632e83ee1dSPeter Xu soft_dirty = pmd_swp_soft_dirty(old_pmd); 2164f45ec5ffSPeter Xu uffd_wp = pmd_swp_uffd_wp(old_pmd); 21652e83ee1dSPeter Xu } else { 2166423ac9afSAneesh Kumar K.V page = pmd_page(old_pmd); 21670ccf7f16SPeter Xu if (pmd_dirty(old_pmd)) { 21680ccf7f16SPeter Xu dirty = true; 2169423ac9afSAneesh Kumar K.V SetPageDirty(page); 21700ccf7f16SPeter Xu } 2171423ac9afSAneesh Kumar K.V write = pmd_write(old_pmd); 2172423ac9afSAneesh Kumar K.V young = pmd_young(old_pmd); 2173423ac9afSAneesh Kumar K.V soft_dirty = pmd_soft_dirty(old_pmd); 2174292924b2SPeter Xu uffd_wp = pmd_uffd_wp(old_pmd); 21756c287605SDavid Hildenbrand 21762e83ee1dSPeter Xu VM_BUG_ON_PAGE(!page_count(page), page); 21776c287605SDavid Hildenbrand 21786c287605SDavid Hildenbrand /* 21796c287605SDavid Hildenbrand * Without "freeze", we'll simply split the PMD, propagating the 21806c287605SDavid Hildenbrand * PageAnonExclusive() flag for each PTE by setting it for 21816c287605SDavid Hildenbrand * each subpage -- no need to (temporarily) clear. 21826c287605SDavid Hildenbrand * 21836c287605SDavid Hildenbrand * With "freeze" we want to replace mapped pages by 21846c287605SDavid Hildenbrand * migration entries right away. This is only possible if we 21856c287605SDavid Hildenbrand * managed to clear PageAnonExclusive() -- see 21866c287605SDavid Hildenbrand * set_pmd_migration_entry(). 21876c287605SDavid Hildenbrand * 21886c287605SDavid Hildenbrand * In case we cannot clear PageAnonExclusive(), split the PMD 21896c287605SDavid Hildenbrand * only and let try_to_migrate_one() fail later. 2190088b8aa5SDavid Hildenbrand * 2191088b8aa5SDavid Hildenbrand * See page_try_share_anon_rmap(): invalidate PMD first. 21926c287605SDavid Hildenbrand */ 21936c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 21946c287605SDavid Hildenbrand if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) 21956c287605SDavid Hildenbrand freeze = false; 219696d82debSHugh Dickins if (!freeze) 219796d82debSHugh Dickins page_ref_add(page, HPAGE_PMD_NR - 1); 21989d84604bSHugh Dickins } 2199eef1b3baSKirill A. Shutemov 2200423ac9afSAneesh Kumar K.V /* 2201423ac9afSAneesh Kumar K.V * Withdraw the table only after we mark the pmd entry invalid. 2202423ac9afSAneesh Kumar K.V * This's critical for some architectures (Power). 2203423ac9afSAneesh Kumar K.V */ 2204eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2205eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2206eef1b3baSKirill A. Shutemov 2207c9c1ee20SHugh Dickins pte = pte_offset_map(&_pmd, haddr); 2208c9c1ee20SHugh Dickins VM_BUG_ON(!pte); 22092ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2210c9c1ee20SHugh Dickins pte_t entry; 2211eef1b3baSKirill A. Shutemov /* 2212eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 2213eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 2214eef1b3baSKirill A. Shutemov * permissions across VMAs. 2215eef1b3baSKirill A. Shutemov */ 221684c3fc4eSZi Yan if (freeze || pmd_migration) { 2217ba988280SKirill A. Shutemov swp_entry_t swp_entry; 22184dd845b5SAlistair Popple if (write) 22194dd845b5SAlistair Popple swp_entry = make_writable_migration_entry( 22204dd845b5SAlistair Popple page_to_pfn(page + i)); 22216c287605SDavid Hildenbrand else if (anon_exclusive) 22226c287605SDavid Hildenbrand swp_entry = make_readable_exclusive_migration_entry( 22236c287605SDavid Hildenbrand page_to_pfn(page + i)); 22244dd845b5SAlistair Popple else 22254dd845b5SAlistair Popple swp_entry = make_readable_migration_entry( 22264dd845b5SAlistair Popple page_to_pfn(page + i)); 22272e346877SPeter Xu if (young) 22282e346877SPeter Xu swp_entry = make_migration_entry_young(swp_entry); 22292e346877SPeter Xu if (dirty) 22302e346877SPeter Xu swp_entry = make_migration_entry_dirty(swp_entry); 2231ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 2232804dd150SAndrea Arcangeli if (soft_dirty) 2233804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 2234f45ec5ffSPeter Xu if (uffd_wp) 2235f45ec5ffSPeter Xu entry = pte_swp_mkuffd_wp(entry); 2236ba988280SKirill A. Shutemov } else { 22376d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 22381462c52eSDavid Hildenbrand if (write) 2239f3ebdf04SDavid Hildenbrand entry = pte_mkwrite(entry); 22406c287605SDavid Hildenbrand if (anon_exclusive) 22416c287605SDavid Hildenbrand SetPageAnonExclusive(page + i); 2242eef1b3baSKirill A. Shutemov if (!young) 2243eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 2244e833bc50SPeter Xu /* NOTE: this may set soft-dirty too on some archs */ 2245e833bc50SPeter Xu if (dirty) 2246e833bc50SPeter Xu entry = pte_mkdirty(entry); 2247804dd150SAndrea Arcangeli if (soft_dirty) 2248804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 2249292924b2SPeter Xu if (uffd_wp) 2250292924b2SPeter Xu entry = pte_mkuffd_wp(entry); 22515ba72b4dSMiaohe Lin page_add_anon_rmap(page + i, vma, addr, RMAP_NONE); 2252ba988280SKirill A. Shutemov } 2253c33c7948SRyan Roberts VM_BUG_ON(!pte_none(ptep_get(pte))); 22542ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 2255c9c1ee20SHugh Dickins pte++; 2256eef1b3baSKirill A. Shutemov } 2257c9c1ee20SHugh Dickins pte_unmap(pte - 1); 2258eef1b3baSKirill A. Shutemov 2259cb67f428SHugh Dickins if (!pmd_migration) 2260cb67f428SHugh Dickins page_remove_rmap(page, vma, true); 226196d82debSHugh Dickins if (freeze) 226296d82debSHugh Dickins put_page(page); 2263eef1b3baSKirill A. Shutemov 2264eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2265eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2266eef1b3baSKirill A. Shutemov } 2267eef1b3baSKirill A. Shutemov 2268eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 2269af28a988SMatthew Wilcox (Oracle) unsigned long address, bool freeze, struct folio *folio) 2270eef1b3baSKirill A. Shutemov { 2271eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2272ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2273eef1b3baSKirill A. Shutemov 22747d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 22756f4f13e8SJérôme Glisse address & HPAGE_PMD_MASK, 2276ac46d4f3SJérôme Glisse (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); 2277ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2278ac46d4f3SJérôme Glisse ptl = pmd_lock(vma->vm_mm, pmd); 227933f4751eSNaoya Horiguchi 228033f4751eSNaoya Horiguchi /* 2281af28a988SMatthew Wilcox (Oracle) * If caller asks to setup a migration entry, we need a folio to check 2282af28a988SMatthew Wilcox (Oracle) * pmd against. Otherwise we can end up replacing wrong folio. 228333f4751eSNaoya Horiguchi */ 2284af28a988SMatthew Wilcox (Oracle) VM_BUG_ON(freeze && !folio); 228583a8441fSMatthew Wilcox (Oracle) VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); 228633f4751eSNaoya Horiguchi 22877f760917SDavid Hildenbrand if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || 228883a8441fSMatthew Wilcox (Oracle) is_pmd_migration_entry(*pmd)) { 2289cea33328SMiaohe Lin /* 2290cea33328SMiaohe Lin * It's safe to call pmd_page when folio is set because it's 2291cea33328SMiaohe Lin * guaranteed that pmd is present. 2292cea33328SMiaohe Lin */ 229383a8441fSMatthew Wilcox (Oracle) if (folio && folio != page_folio(pmd_page(*pmd))) 229483a8441fSMatthew Wilcox (Oracle) goto out; 2295ac46d4f3SJérôme Glisse __split_huge_pmd_locked(vma, pmd, range.start, freeze); 229683a8441fSMatthew Wilcox (Oracle) } 22977f760917SDavid Hildenbrand 2298e90309c9SKirill A. Shutemov out: 2299eef1b3baSKirill A. Shutemov spin_unlock(ptl); 2300ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 2301eef1b3baSKirill A. Shutemov } 2302eef1b3baSKirill A. Shutemov 2303fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2304af28a988SMatthew Wilcox (Oracle) bool freeze, struct folio *folio) 230594fcc585SAndrea Arcangeli { 230650722804SZach O'Keefe pmd_t *pmd = mm_find_pmd(vma->vm_mm, address); 230794fcc585SAndrea Arcangeli 230850722804SZach O'Keefe if (!pmd) 2309f72e7dcdSHugh Dickins return; 2310f72e7dcdSHugh Dickins 2311af28a988SMatthew Wilcox (Oracle) __split_huge_pmd(vma, pmd, address, freeze, folio); 231294fcc585SAndrea Arcangeli } 231394fcc585SAndrea Arcangeli 231471f9e58eSMiaohe Lin static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) 231571f9e58eSMiaohe Lin { 231671f9e58eSMiaohe Lin /* 231771f9e58eSMiaohe Lin * If the new address isn't hpage aligned and it could previously 231871f9e58eSMiaohe Lin * contain an hugepage: check if we need to split an huge pmd. 231971f9e58eSMiaohe Lin */ 232071f9e58eSMiaohe Lin if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && 232171f9e58eSMiaohe Lin range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), 232271f9e58eSMiaohe Lin ALIGN(address, HPAGE_PMD_SIZE))) 232371f9e58eSMiaohe Lin split_huge_pmd_address(vma, address, false, NULL); 232471f9e58eSMiaohe Lin } 232571f9e58eSMiaohe Lin 2326e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 232794fcc585SAndrea Arcangeli unsigned long start, 232894fcc585SAndrea Arcangeli unsigned long end, 232994fcc585SAndrea Arcangeli long adjust_next) 233094fcc585SAndrea Arcangeli { 233171f9e58eSMiaohe Lin /* Check if we need to split start first. */ 233271f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, start); 233371f9e58eSMiaohe Lin 233471f9e58eSMiaohe Lin /* Check if we need to split end next. */ 233571f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, end); 233694fcc585SAndrea Arcangeli 233794fcc585SAndrea Arcangeli /* 233868540502SMatthew Wilcox (Oracle) * If we're also updating the next vma vm_start, 233971f9e58eSMiaohe Lin * check if we need to split it. 234094fcc585SAndrea Arcangeli */ 234194fcc585SAndrea Arcangeli if (adjust_next > 0) { 234268540502SMatthew Wilcox (Oracle) struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end); 234394fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 2344f9d86a60SWei Yang nstart += adjust_next; 234571f9e58eSMiaohe Lin split_huge_pmd_if_needed(next, nstart); 234694fcc585SAndrea Arcangeli } 234794fcc585SAndrea Arcangeli } 2348e9b61f19SKirill A. Shutemov 2349684555aaSMatthew Wilcox (Oracle) static void unmap_folio(struct folio *folio) 2350e9b61f19SKirill A. Shutemov { 2351a98a2f0cSAlistair Popple enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | 2352a98a2f0cSAlistair Popple TTU_SYNC; 2353e9b61f19SKirill A. Shutemov 2354684555aaSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2355e9b61f19SKirill A. Shutemov 2356a98a2f0cSAlistair Popple /* 2357a98a2f0cSAlistair Popple * Anon pages need migration entries to preserve them, but file 2358a98a2f0cSAlistair Popple * pages can simply be left unmapped, then faulted back on demand. 2359a98a2f0cSAlistair Popple * If that is ever changed (perhaps for mlock), update remap_page(). 2360a98a2f0cSAlistair Popple */ 23614b8554c5SMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 23624b8554c5SMatthew Wilcox (Oracle) try_to_migrate(folio, ttu_flags); 2363a98a2f0cSAlistair Popple else 2364869f7ee6SMatthew Wilcox (Oracle) try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); 2365bd56086fSKirill A. Shutemov } 2366bd56086fSKirill A. Shutemov 23674eecb8b9SMatthew Wilcox (Oracle) static void remap_page(struct folio *folio, unsigned long nr) 2368e9b61f19SKirill A. Shutemov { 23694eecb8b9SMatthew Wilcox (Oracle) int i = 0; 2370ab02c252SHugh Dickins 2371684555aaSMatthew Wilcox (Oracle) /* If unmap_folio() uses try_to_migrate() on file, remove this check */ 23724eecb8b9SMatthew Wilcox (Oracle) if (!folio_test_anon(folio)) 2373ab02c252SHugh Dickins return; 23744eecb8b9SMatthew Wilcox (Oracle) for (;;) { 23754eecb8b9SMatthew Wilcox (Oracle) remove_migration_ptes(folio, folio, true); 23764eecb8b9SMatthew Wilcox (Oracle) i += folio_nr_pages(folio); 23774eecb8b9SMatthew Wilcox (Oracle) if (i >= nr) 23784eecb8b9SMatthew Wilcox (Oracle) break; 23794eecb8b9SMatthew Wilcox (Oracle) folio = folio_next(folio); 2380e9b61f19SKirill A. Shutemov } 2381ace71a19SKirill A. Shutemov } 2382e9b61f19SKirill A. Shutemov 238394866635SAlex Shi static void lru_add_page_tail(struct page *head, struct page *tail, 238488dcb9a3SAlex Shi struct lruvec *lruvec, struct list_head *list) 238588dcb9a3SAlex Shi { 238694866635SAlex Shi VM_BUG_ON_PAGE(!PageHead(head), head); 238794866635SAlex Shi VM_BUG_ON_PAGE(PageCompound(tail), head); 238894866635SAlex Shi VM_BUG_ON_PAGE(PageLRU(tail), head); 23896168d0daSAlex Shi lockdep_assert_held(&lruvec->lru_lock); 239088dcb9a3SAlex Shi 23916dbb5741SAlex Shi if (list) { 239288dcb9a3SAlex Shi /* page reclaim is reclaiming a huge page */ 23936dbb5741SAlex Shi VM_WARN_ON(PageLRU(head)); 239494866635SAlex Shi get_page(tail); 239594866635SAlex Shi list_add_tail(&tail->lru, list); 239688dcb9a3SAlex Shi } else { 23976dbb5741SAlex Shi /* head is still on lru (and we have it frozen) */ 23986dbb5741SAlex Shi VM_WARN_ON(!PageLRU(head)); 239907ca7606SHugh Dickins if (PageUnevictable(tail)) 240007ca7606SHugh Dickins tail->mlock_count = 0; 240107ca7606SHugh Dickins else 24026dbb5741SAlex Shi list_add_tail(&tail->lru, &head->lru); 240307ca7606SHugh Dickins SetPageLRU(tail); 240488dcb9a3SAlex Shi } 240588dcb9a3SAlex Shi } 240688dcb9a3SAlex Shi 24078df651c7SKirill A. Shutemov static void __split_huge_page_tail(struct page *head, int tail, 2408e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2409e9b61f19SKirill A. Shutemov { 2410e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 2411e9b61f19SKirill A. Shutemov 24128df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2413e9b61f19SKirill A. Shutemov 2414e9b61f19SKirill A. Shutemov /* 2415605ca5edSKonstantin Khlebnikov * Clone page flags before unfreezing refcount. 2416605ca5edSKonstantin Khlebnikov * 2417605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow flags change, 24188958b249SHaitao Shi * for example lock_page() which set PG_waiters. 24196c287605SDavid Hildenbrand * 24206c287605SDavid Hildenbrand * Note that for mapped sub-pages of an anonymous THP, 2421684555aaSMatthew Wilcox (Oracle) * PG_anon_exclusive has been cleared in unmap_folio() and is stored in 24226c287605SDavid Hildenbrand * the migration entry instead from where remap_page() will restore it. 24236c287605SDavid Hildenbrand * We can still have PG_anon_exclusive set on effectively unmapped and 24246c287605SDavid Hildenbrand * unreferenced sub-pages of an anonymous THP: we can simply drop 24256c287605SDavid Hildenbrand * PG_anon_exclusive (-> PG_mappedtodisk) for these here. 2426e9b61f19SKirill A. Shutemov */ 2427e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2428e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2429e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2430e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 243138d8b4e6SHuang Ying (1L << PG_swapcache) | 2432e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2433e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2434e9b61f19SKirill A. Shutemov (1L << PG_active) | 24351899ad18SJohannes Weiner (1L << PG_workingset) | 2436e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2437b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 2438b0284cd2SCatalin Marinas #ifdef CONFIG_ARCH_USES_PG_ARCH_X 243972e6afa0SCatalin Marinas (1L << PG_arch_2) | 2440ef6458b1SPeter Collingbourne (1L << PG_arch_3) | 244172e6afa0SCatalin Marinas #endif 2442ec1c86b2SYu Zhao (1L << PG_dirty) | 2443ec1c86b2SYu Zhao LRU_GEN_MASK | LRU_REFS_MASK)); 2444e9b61f19SKirill A. Shutemov 2445cb67f428SHugh Dickins /* ->mapping in first and second tail page is replaced by other uses */ 2446173d9d9fSHugh Dickins VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2447173d9d9fSHugh Dickins page_tail); 2448173d9d9fSHugh Dickins page_tail->mapping = head->mapping; 2449173d9d9fSHugh Dickins page_tail->index = head->index + tail; 245071e2d666SMel Gorman 245171e2d666SMel Gorman /* 245271e2d666SMel Gorman * page->private should not be set in tail pages with the exception 245371e2d666SMel Gorman * of swap cache pages that store the swp_entry_t in tail pages. 245471e2d666SMel Gorman * Fix up and warn once if private is unexpectedly set. 2455cb67f428SHugh Dickins * 245694688e8eSMatthew Wilcox (Oracle) * What of 32-bit systems, on which folio->_pincount overlays 2457cb67f428SHugh Dickins * head[1].private? No problem: THP_SWAP is not enabled on 32-bit, and 245894688e8eSMatthew Wilcox (Oracle) * pincount must be 0 for folio_ref_freeze() to have succeeded. 245971e2d666SMel Gorman */ 246071e2d666SMel Gorman if (!folio_test_swapcache(page_folio(head))) { 24615aae9265SHugh Dickins VM_WARN_ON_ONCE_PAGE(page_tail->private != 0, page_tail); 2462b653db77SMatthew Wilcox (Oracle) page_tail->private = 0; 246371e2d666SMel Gorman } 2464173d9d9fSHugh Dickins 2465605ca5edSKonstantin Khlebnikov /* Page flags must be visible before we make the page non-compound. */ 2466e9b61f19SKirill A. Shutemov smp_wmb(); 2467e9b61f19SKirill A. Shutemov 2468605ca5edSKonstantin Khlebnikov /* 2469605ca5edSKonstantin Khlebnikov * Clear PageTail before unfreezing page refcount. 2470605ca5edSKonstantin Khlebnikov * 2471605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow put_page() 2472605ca5edSKonstantin Khlebnikov * which needs correct compound_head(). 2473605ca5edSKonstantin Khlebnikov */ 2474e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2475e9b61f19SKirill A. Shutemov 2476605ca5edSKonstantin Khlebnikov /* Finally unfreeze refcount. Additional reference from page cache. */ 2477605ca5edSKonstantin Khlebnikov page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || 2478605ca5edSKonstantin Khlebnikov PageSwapCache(head))); 2479605ca5edSKonstantin Khlebnikov 2480e9b61f19SKirill A. Shutemov if (page_is_young(head)) 2481e9b61f19SKirill A. Shutemov set_page_young(page_tail); 2482e9b61f19SKirill A. Shutemov if (page_is_idle(head)) 2483e9b61f19SKirill A. Shutemov set_page_idle(page_tail); 2484e9b61f19SKirill A. Shutemov 2485e9b61f19SKirill A. Shutemov page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); 248694723aafSMichal Hocko 248794723aafSMichal Hocko /* 248894723aafSMichal Hocko * always add to the tail because some iterators expect new 248994723aafSMichal Hocko * pages to show after the currently processed elements - e.g. 249094723aafSMichal Hocko * migrate_pages 249194723aafSMichal Hocko */ 2492e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2493e9b61f19SKirill A. Shutemov } 2494e9b61f19SKirill A. Shutemov 2495baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2496b6769834SAlex Shi pgoff_t end) 2497e9b61f19SKirill A. Shutemov { 2498e809c3feSMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2499e809c3feSMatthew Wilcox (Oracle) struct page *head = &folio->page; 2500e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 25014101196bSMatthew Wilcox (Oracle) struct address_space *swap_cache = NULL; 25024101196bSMatthew Wilcox (Oracle) unsigned long offset = 0; 25038cce5475SKirill A. Shutemov unsigned int nr = thp_nr_pages(head); 25048df651c7SKirill A. Shutemov int i; 2505e9b61f19SKirill A. Shutemov 2506e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2507be6c8982SZhou Guanghui split_page_memcg(head, nr); 2508e9b61f19SKirill A. Shutemov 25094101196bSMatthew Wilcox (Oracle) if (PageAnon(head) && PageSwapCache(head)) { 25104101196bSMatthew Wilcox (Oracle) swp_entry_t entry = { .val = page_private(head) }; 25114101196bSMatthew Wilcox (Oracle) 25124101196bSMatthew Wilcox (Oracle) offset = swp_offset(entry); 25134101196bSMatthew Wilcox (Oracle) swap_cache = swap_address_space(entry); 25144101196bSMatthew Wilcox (Oracle) xa_lock(&swap_cache->i_pages); 25154101196bSMatthew Wilcox (Oracle) } 25164101196bSMatthew Wilcox (Oracle) 2517f0953a1bSIngo Molnar /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ 2518e809c3feSMatthew Wilcox (Oracle) lruvec = folio_lruvec_lock(folio); 2519b6769834SAlex Shi 2520eac96c3eSYang Shi ClearPageHasHWPoisoned(head); 2521eac96c3eSYang Shi 25228cce5475SKirill A. Shutemov for (i = nr - 1; i >= 1; i--) { 25238df651c7SKirill A. Shutemov __split_huge_page_tail(head, i, lruvec, list); 2524d144bf62SHugh Dickins /* Some pages can be beyond EOF: drop them from page cache */ 2525baa355fdSKirill A. Shutemov if (head[i].index >= end) { 2526fb5c2029SMatthew Wilcox (Oracle) struct folio *tail = page_folio(head + i); 2527fb5c2029SMatthew Wilcox (Oracle) 2528d144bf62SHugh Dickins if (shmem_mapping(head->mapping)) 2529800d8c63SKirill A. Shutemov shmem_uncharge(head->mapping->host, 1); 2530fb5c2029SMatthew Wilcox (Oracle) else if (folio_test_clear_dirty(tail)) 2531fb5c2029SMatthew Wilcox (Oracle) folio_account_cleaned(tail, 2532fb5c2029SMatthew Wilcox (Oracle) inode_to_wb(folio->mapping->host)); 2533fb5c2029SMatthew Wilcox (Oracle) __filemap_remove_folio(tail, NULL); 2534fb5c2029SMatthew Wilcox (Oracle) folio_put(tail); 25354101196bSMatthew Wilcox (Oracle) } else if (!PageAnon(page)) { 25364101196bSMatthew Wilcox (Oracle) __xa_store(&head->mapping->i_pages, head[i].index, 25374101196bSMatthew Wilcox (Oracle) head + i, 0); 25384101196bSMatthew Wilcox (Oracle) } else if (swap_cache) { 25394101196bSMatthew Wilcox (Oracle) __xa_store(&swap_cache->i_pages, offset + i, 25404101196bSMatthew Wilcox (Oracle) head + i, 0); 2541baa355fdSKirill A. Shutemov } 2542baa355fdSKirill A. Shutemov } 2543e9b61f19SKirill A. Shutemov 2544e9b61f19SKirill A. Shutemov ClearPageCompound(head); 25456168d0daSAlex Shi unlock_page_lruvec(lruvec); 2546b6769834SAlex Shi /* Caller disabled irqs, so they are still disabled here */ 2547f7da677bSVlastimil Babka 25488cce5475SKirill A. Shutemov split_page_owner(head, nr); 2549f7da677bSVlastimil Babka 2550baa355fdSKirill A. Shutemov /* See comment in __split_huge_page_tail() */ 2551baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2552aa5dc07fSMatthew Wilcox /* Additional pin to swap cache */ 25534101196bSMatthew Wilcox (Oracle) if (PageSwapCache(head)) { 255438d8b4e6SHuang Ying page_ref_add(head, 2); 25554101196bSMatthew Wilcox (Oracle) xa_unlock(&swap_cache->i_pages); 25564101196bSMatthew Wilcox (Oracle) } else { 2557baa355fdSKirill A. Shutemov page_ref_inc(head); 25584101196bSMatthew Wilcox (Oracle) } 2559baa355fdSKirill A. Shutemov } else { 2560aa5dc07fSMatthew Wilcox /* Additional pin to page cache */ 2561baa355fdSKirill A. Shutemov page_ref_add(head, 2); 2562b93b0163SMatthew Wilcox xa_unlock(&head->mapping->i_pages); 2563baa355fdSKirill A. Shutemov } 2564b6769834SAlex Shi local_irq_enable(); 2565e9b61f19SKirill A. Shutemov 25664eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, nr); 2567e9b61f19SKirill A. Shutemov 2568c4f9c701SHuang Ying if (PageSwapCache(head)) { 2569c4f9c701SHuang Ying swp_entry_t entry = { .val = page_private(head) }; 2570c4f9c701SHuang Ying 2571c4f9c701SHuang Ying split_swap_cluster(entry); 2572c4f9c701SHuang Ying } 2573c4f9c701SHuang Ying 25748cce5475SKirill A. Shutemov for (i = 0; i < nr; i++) { 2575e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2576e9b61f19SKirill A. Shutemov if (subpage == page) 2577e9b61f19SKirill A. Shutemov continue; 2578e9b61f19SKirill A. Shutemov unlock_page(subpage); 2579e9b61f19SKirill A. Shutemov 2580e9b61f19SKirill A. Shutemov /* 2581e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2582e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2583e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2584e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2585e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2586e9b61f19SKirill A. Shutemov */ 25870b175468SMiaohe Lin free_page_and_swap_cache(subpage); 2588e9b61f19SKirill A. Shutemov } 2589e9b61f19SKirill A. Shutemov } 2590e9b61f19SKirill A. Shutemov 2591b8f593cdSHuang Ying /* Racy check whether the huge page can be split */ 2592d4b4084aSMatthew Wilcox (Oracle) bool can_split_folio(struct folio *folio, int *pextra_pins) 2593b8f593cdSHuang Ying { 2594b8f593cdSHuang Ying int extra_pins; 2595b8f593cdSHuang Ying 2596aa5dc07fSMatthew Wilcox /* Additional pins from page cache */ 2597d4b4084aSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 2598d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_test_swapcache(folio) ? 2599d4b4084aSMatthew Wilcox (Oracle) folio_nr_pages(folio) : 0; 2600b8f593cdSHuang Ying else 2601d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_nr_pages(folio); 2602b8f593cdSHuang Ying if (pextra_pins) 2603b8f593cdSHuang Ying *pextra_pins = extra_pins; 2604d4b4084aSMatthew Wilcox (Oracle) return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; 2605b8f593cdSHuang Ying } 2606b8f593cdSHuang Ying 26076d0a07edSAndrea Arcangeli /* 2608e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2609e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2610e9b61f19SKirill A. Shutemov * 2611e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2612e9b61f19SKirill A. Shutemov * The huge page must be locked. 2613e9b61f19SKirill A. Shutemov * 2614e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2615e9b61f19SKirill A. Shutemov * 2616e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2617e9b61f19SKirill A. Shutemov * the hugepage. 2618e9b61f19SKirill A. Shutemov * 2619e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2620e9b61f19SKirill A. Shutemov * they are not mapped. 2621e9b61f19SKirill A. Shutemov * 2622e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2623e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2624e9b61f19SKirill A. Shutemov * us. 2625e9b61f19SKirill A. Shutemov */ 2626e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2627e9b61f19SKirill A. Shutemov { 26284eecb8b9SMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2629f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *ds_queue = get_deferred_split_queue(folio); 26303e9a13daSMatthew Wilcox (Oracle) XA_STATE(xas, &folio->mapping->i_pages, folio->index); 2631baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2632baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2633504e070dSYang Shi int extra_pins, ret; 2634006d3ff2SHugh Dickins pgoff_t end; 2635478d134eSXu Yu bool is_hzp; 2636e9b61f19SKirill A. Shutemov 26373e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); 26383e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2639e9b61f19SKirill A. Shutemov 26403e9a13daSMatthew Wilcox (Oracle) is_hzp = is_huge_zero_page(&folio->page); 26414737edbbSNaoya Horiguchi if (is_hzp) { 26424737edbbSNaoya Horiguchi pr_warn_ratelimited("Called split_huge_page for huge zero page\n"); 2643478d134eSXu Yu return -EBUSY; 26444737edbbSNaoya Horiguchi } 2645478d134eSXu Yu 26463e9a13daSMatthew Wilcox (Oracle) if (folio_test_writeback(folio)) 264759807685SHuang Ying return -EBUSY; 264859807685SHuang Ying 26493e9a13daSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) { 2650e9b61f19SKirill A. Shutemov /* 2651c1e8d7c6SMichel Lespinasse * The caller does not necessarily hold an mmap_lock that would 2652baa355fdSKirill A. Shutemov * prevent the anon_vma disappearing so we first we take a 2653baa355fdSKirill A. Shutemov * reference to it and then lock the anon_vma for write. This 26542f031c6fSMatthew Wilcox (Oracle) * is similar to folio_lock_anon_vma_read except the write lock 2655baa355fdSKirill A. Shutemov * is taken to serialise against parallel split or collapse 2656baa355fdSKirill A. Shutemov * operations. 2657e9b61f19SKirill A. Shutemov */ 265829eea9b5SMatthew Wilcox (Oracle) anon_vma = folio_get_anon_vma(folio); 2659e9b61f19SKirill A. Shutemov if (!anon_vma) { 2660e9b61f19SKirill A. Shutemov ret = -EBUSY; 2661e9b61f19SKirill A. Shutemov goto out; 2662e9b61f19SKirill A. Shutemov } 2663006d3ff2SHugh Dickins end = -1; 2664baa355fdSKirill A. Shutemov mapping = NULL; 2665e9b61f19SKirill A. Shutemov anon_vma_lock_write(anon_vma); 2666baa355fdSKirill A. Shutemov } else { 26676a3edd29SYin Fengwei gfp_t gfp; 26686a3edd29SYin Fengwei 26693e9a13daSMatthew Wilcox (Oracle) mapping = folio->mapping; 2670baa355fdSKirill A. Shutemov 2671baa355fdSKirill A. Shutemov /* Truncated ? */ 2672baa355fdSKirill A. Shutemov if (!mapping) { 2673baa355fdSKirill A. Shutemov ret = -EBUSY; 2674baa355fdSKirill A. Shutemov goto out; 2675baa355fdSKirill A. Shutemov } 2676baa355fdSKirill A. Shutemov 26776a3edd29SYin Fengwei gfp = current_gfp_context(mapping_gfp_mask(mapping) & 26786a3edd29SYin Fengwei GFP_RECLAIM_MASK); 26796a3edd29SYin Fengwei 26800201ebf2SDavid Howells if (!filemap_release_folio(folio, gfp)) { 26816a3edd29SYin Fengwei ret = -EBUSY; 26826a3edd29SYin Fengwei goto out; 26836a3edd29SYin Fengwei } 26846a3edd29SYin Fengwei 26853e9a13daSMatthew Wilcox (Oracle) xas_split_alloc(&xas, folio, folio_order(folio), gfp); 26866b24ca4aSMatthew Wilcox (Oracle) if (xas_error(&xas)) { 26876b24ca4aSMatthew Wilcox (Oracle) ret = xas_error(&xas); 26886b24ca4aSMatthew Wilcox (Oracle) goto out; 26896b24ca4aSMatthew Wilcox (Oracle) } 26906b24ca4aSMatthew Wilcox (Oracle) 2691baa355fdSKirill A. Shutemov anon_vma = NULL; 2692baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 2693006d3ff2SHugh Dickins 2694006d3ff2SHugh Dickins /* 2695006d3ff2SHugh Dickins *__split_huge_page() may need to trim off pages beyond EOF: 2696006d3ff2SHugh Dickins * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, 2697006d3ff2SHugh Dickins * which cannot be nested inside the page tree lock. So note 2698006d3ff2SHugh Dickins * end now: i_size itself may be changed at any moment, but 26993e9a13daSMatthew Wilcox (Oracle) * folio lock is good enough to serialize the trimming. 2700006d3ff2SHugh Dickins */ 2701006d3ff2SHugh Dickins end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); 2702d144bf62SHugh Dickins if (shmem_mapping(mapping)) 2703d144bf62SHugh Dickins end = shmem_fallocend(mapping->host, end); 2704baa355fdSKirill A. Shutemov } 2705e9b61f19SKirill A. Shutemov 2706e9b61f19SKirill A. Shutemov /* 2707684555aaSMatthew Wilcox (Oracle) * Racy check if we can split the page, before unmap_folio() will 2708e9b61f19SKirill A. Shutemov * split PMDs 2709e9b61f19SKirill A. Shutemov */ 2710d4b4084aSMatthew Wilcox (Oracle) if (!can_split_folio(folio, &extra_pins)) { 2711fd4a7ac3SBaolin Wang ret = -EAGAIN; 2712e9b61f19SKirill A. Shutemov goto out_unlock; 2713e9b61f19SKirill A. Shutemov } 2714e9b61f19SKirill A. Shutemov 2715684555aaSMatthew Wilcox (Oracle) unmap_folio(folio); 2716e9b61f19SKirill A. Shutemov 2717b6769834SAlex Shi /* block interrupt reentry in xa_lock and spinlock */ 2718b6769834SAlex Shi local_irq_disable(); 2719baa355fdSKirill A. Shutemov if (mapping) { 2720baa355fdSKirill A. Shutemov /* 27213e9a13daSMatthew Wilcox (Oracle) * Check if the folio is present in page cache. 27223e9a13daSMatthew Wilcox (Oracle) * We assume all tail are present too, if folio is there. 2723baa355fdSKirill A. Shutemov */ 27246b24ca4aSMatthew Wilcox (Oracle) xas_lock(&xas); 27256b24ca4aSMatthew Wilcox (Oracle) xas_reset(&xas); 27263e9a13daSMatthew Wilcox (Oracle) if (xas_load(&xas) != folio) 2727baa355fdSKirill A. Shutemov goto fail; 2728baa355fdSKirill A. Shutemov } 2729baa355fdSKirill A. Shutemov 27300139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 2731364c1eebSYang Shi spin_lock(&ds_queue->split_queue_lock); 27323e9a13daSMatthew Wilcox (Oracle) if (folio_ref_freeze(folio, 1 + extra_pins)) { 27334375a553SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) { 2734364c1eebSYang Shi ds_queue->split_queue_len--; 27354375a553SMatthew Wilcox (Oracle) list_del(&folio->_deferred_list); 27369a982250SKirill A. Shutemov } 2737afb97172SWei Yang spin_unlock(&ds_queue->split_queue_lock); 273806d3eff6SKirill A. Shutemov if (mapping) { 27393e9a13daSMatthew Wilcox (Oracle) int nr = folio_nr_pages(folio); 2740bf9eceadSMuchun Song 27413e9a13daSMatthew Wilcox (Oracle) xas_split(&xas, folio, folio_order(folio)); 27423e9a13daSMatthew Wilcox (Oracle) if (folio_test_swapbacked(folio)) { 27433e9a13daSMatthew Wilcox (Oracle) __lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, 274457b2847dSMuchun Song -nr); 27451ca7554dSMarek Szyprowski } else { 27463e9a13daSMatthew Wilcox (Oracle) __lruvec_stat_mod_folio(folio, NR_FILE_THPS, 2747bf9eceadSMuchun Song -nr); 27481ca7554dSMarek Szyprowski filemap_nr_thps_dec(mapping); 27491ca7554dSMarek Szyprowski } 275006d3eff6SKirill A. Shutemov } 275106d3eff6SKirill A. Shutemov 2752b6769834SAlex Shi __split_huge_page(page, list, end); 2753e9b61f19SKirill A. Shutemov ret = 0; 2754baa355fdSKirill A. Shutemov } else { 2755364c1eebSYang Shi spin_unlock(&ds_queue->split_queue_lock); 2756504e070dSYang Shi fail: 2757504e070dSYang Shi if (mapping) 27586b24ca4aSMatthew Wilcox (Oracle) xas_unlock(&xas); 2759b6769834SAlex Shi local_irq_enable(); 27604eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, folio_nr_pages(folio)); 2761fd4a7ac3SBaolin Wang ret = -EAGAIN; 2762e9b61f19SKirill A. Shutemov } 2763e9b61f19SKirill A. Shutemov 2764e9b61f19SKirill A. Shutemov out_unlock: 2765baa355fdSKirill A. Shutemov if (anon_vma) { 2766e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 2767e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 2768baa355fdSKirill A. Shutemov } 2769baa355fdSKirill A. Shutemov if (mapping) 2770baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 2771e9b61f19SKirill A. Shutemov out: 277269a37a8bSMatthew Wilcox (Oracle) xas_destroy(&xas); 2773e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 2774e9b61f19SKirill A. Shutemov return ret; 2775e9b61f19SKirill A. Shutemov } 27769a982250SKirill A. Shutemov 27778dc4a8f1SMatthew Wilcox (Oracle) void folio_undo_large_rmappable(struct folio *folio) 27789a982250SKirill A. Shutemov { 27798dc4a8f1SMatthew Wilcox (Oracle) struct deferred_split *ds_queue; 27809a982250SKirill A. Shutemov unsigned long flags; 27819a982250SKirill A. Shutemov 2782deedad80SYin Fengwei /* 2783deedad80SYin Fengwei * At this point, there is no one trying to add the folio to 2784deedad80SYin Fengwei * deferred_list. If folio is not in deferred_list, it's safe 2785deedad80SYin Fengwei * to check without acquiring the split_queue_lock. 2786deedad80SYin Fengwei */ 27878dc4a8f1SMatthew Wilcox (Oracle) if (data_race(list_empty(&folio->_deferred_list))) 27888dc4a8f1SMatthew Wilcox (Oracle) return; 27898dc4a8f1SMatthew Wilcox (Oracle) 27908dc4a8f1SMatthew Wilcox (Oracle) ds_queue = get_deferred_split_queue(folio); 2791364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 27928991de90SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) { 2793364c1eebSYang Shi ds_queue->split_queue_len--; 27948991de90SMatthew Wilcox (Oracle) list_del(&folio->_deferred_list); 27959a982250SKirill A. Shutemov } 2796364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 2797deedad80SYin Fengwei } 27989a982250SKirill A. Shutemov 2799f158ed61SMatthew Wilcox (Oracle) void deferred_split_folio(struct folio *folio) 28009a982250SKirill A. Shutemov { 2801f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *ds_queue = get_deferred_split_queue(folio); 280287eaceb3SYang Shi #ifdef CONFIG_MEMCG 28038991de90SMatthew Wilcox (Oracle) struct mem_cgroup *memcg = folio_memcg(folio); 280487eaceb3SYang Shi #endif 28059a982250SKirill A. Shutemov unsigned long flags; 28069a982250SKirill A. Shutemov 28078991de90SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); 28089a982250SKirill A. Shutemov 280987eaceb3SYang Shi /* 281087eaceb3SYang Shi * The try_to_unmap() in page reclaim path might reach here too, 281187eaceb3SYang Shi * this may cause a race condition to corrupt deferred split queue. 28128991de90SMatthew Wilcox (Oracle) * And, if page reclaim is already handling the same folio, it is 281387eaceb3SYang Shi * unnecessary to handle it again in shrinker. 281487eaceb3SYang Shi * 28158991de90SMatthew Wilcox (Oracle) * Check the swapcache flag to determine if the folio is being 28168991de90SMatthew Wilcox (Oracle) * handled by page reclaim since THP swap would add the folio into 281787eaceb3SYang Shi * swap cache before calling try_to_unmap(). 281887eaceb3SYang Shi */ 28198991de90SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 282087eaceb3SYang Shi return; 282187eaceb3SYang Shi 28228991de90SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) 28239a982250SKirill A. Shutemov return; 28249a982250SKirill A. Shutemov 2825364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28268991de90SMatthew Wilcox (Oracle) if (list_empty(&folio->_deferred_list)) { 2827f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 28288991de90SMatthew Wilcox (Oracle) list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); 2829364c1eebSYang Shi ds_queue->split_queue_len++; 283087eaceb3SYang Shi #ifdef CONFIG_MEMCG 283187eaceb3SYang Shi if (memcg) 28328991de90SMatthew Wilcox (Oracle) set_shrinker_bit(memcg, folio_nid(folio), 283387eaceb3SYang Shi deferred_split_shrinker.id); 283487eaceb3SYang Shi #endif 28359a982250SKirill A. Shutemov } 2836364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28379a982250SKirill A. Shutemov } 28389a982250SKirill A. Shutemov 28399a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 28409a982250SKirill A. Shutemov struct shrink_control *sc) 28419a982250SKirill A. Shutemov { 2842a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2843364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 284487eaceb3SYang Shi 284587eaceb3SYang Shi #ifdef CONFIG_MEMCG 284687eaceb3SYang Shi if (sc->memcg) 284787eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 284887eaceb3SYang Shi #endif 2849364c1eebSYang Shi return READ_ONCE(ds_queue->split_queue_len); 28509a982250SKirill A. Shutemov } 28519a982250SKirill A. Shutemov 28529a982250SKirill A. Shutemov static unsigned long deferred_split_scan(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; 28579a982250SKirill A. Shutemov unsigned long flags; 28584375a553SMatthew Wilcox (Oracle) LIST_HEAD(list); 28594375a553SMatthew Wilcox (Oracle) struct folio *folio, *next; 28609a982250SKirill A. Shutemov int split = 0; 28619a982250SKirill A. Shutemov 286287eaceb3SYang Shi #ifdef CONFIG_MEMCG 286387eaceb3SYang Shi if (sc->memcg) 286487eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 286587eaceb3SYang Shi #endif 286687eaceb3SYang Shi 2867364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28689a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 28694375a553SMatthew Wilcox (Oracle) list_for_each_entry_safe(folio, next, &ds_queue->split_queue, 28704375a553SMatthew Wilcox (Oracle) _deferred_list) { 28714375a553SMatthew Wilcox (Oracle) if (folio_try_get(folio)) { 28724375a553SMatthew Wilcox (Oracle) list_move(&folio->_deferred_list, &list); 2873e3ae1953SKirill A. Shutemov } else { 28744375a553SMatthew Wilcox (Oracle) /* We lost race with folio_put() */ 28754375a553SMatthew Wilcox (Oracle) list_del_init(&folio->_deferred_list); 2876364c1eebSYang Shi ds_queue->split_queue_len--; 28779a982250SKirill A. Shutemov } 2878e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 2879e3ae1953SKirill A. Shutemov break; 28809a982250SKirill A. Shutemov } 2881364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28829a982250SKirill A. Shutemov 28834375a553SMatthew Wilcox (Oracle) list_for_each_entry_safe(folio, next, &list, _deferred_list) { 28844375a553SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 2885fa41b900SKirill A. Shutemov goto next; 28869a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 28874375a553SMatthew Wilcox (Oracle) if (!split_folio(folio)) 28889a982250SKirill A. Shutemov split++; 28894375a553SMatthew Wilcox (Oracle) folio_unlock(folio); 2890fa41b900SKirill A. Shutemov next: 28914375a553SMatthew Wilcox (Oracle) folio_put(folio); 28929a982250SKirill A. Shutemov } 28939a982250SKirill A. Shutemov 2894364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 2895364c1eebSYang Shi list_splice_tail(&list, &ds_queue->split_queue); 2896364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28979a982250SKirill A. Shutemov 2898cb8d68ecSKirill A. Shutemov /* 2899cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 2900cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 2901cb8d68ecSKirill A. Shutemov */ 2902364c1eebSYang Shi if (!split && list_empty(&ds_queue->split_queue)) 2903cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 2904cb8d68ecSKirill A. Shutemov return split; 29059a982250SKirill A. Shutemov } 29069a982250SKirill A. Shutemov 29079a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker = { 29089a982250SKirill A. Shutemov .count_objects = deferred_split_count, 29099a982250SKirill A. Shutemov .scan_objects = deferred_split_scan, 29109a982250SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 291187eaceb3SYang Shi .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | 291287eaceb3SYang Shi SHRINKER_NONSLAB, 29139a982250SKirill A. Shutemov }; 291449071d43SKirill A. Shutemov 291549071d43SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 2916fa6c0231SZi Yan static void split_huge_pages_all(void) 291749071d43SKirill A. Shutemov { 291849071d43SKirill A. Shutemov struct zone *zone; 291949071d43SKirill A. Shutemov struct page *page; 2920630e7c5eSKefeng Wang struct folio *folio; 292149071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 292249071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 292349071d43SKirill A. Shutemov 2924fa6c0231SZi Yan pr_debug("Split all THPs\n"); 2925a17206daSMiaohe Lin for_each_zone(zone) { 2926a17206daSMiaohe Lin if (!managed_zone(zone)) 2927a17206daSMiaohe Lin continue; 292849071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 292949071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 2930a17206daSMiaohe Lin int nr_pages; 293149071d43SKirill A. Shutemov 29322b7aa91bSNaoya Horiguchi page = pfn_to_online_page(pfn); 2933630e7c5eSKefeng Wang if (!page || PageTail(page)) 2934630e7c5eSKefeng Wang continue; 2935630e7c5eSKefeng Wang folio = page_folio(page); 2936630e7c5eSKefeng Wang if (!folio_try_get(folio)) 293749071d43SKirill A. Shutemov continue; 293849071d43SKirill A. Shutemov 2939630e7c5eSKefeng Wang if (unlikely(page_folio(page) != folio)) 294049071d43SKirill A. Shutemov goto next; 294149071d43SKirill A. Shutemov 2942630e7c5eSKefeng Wang if (zone != folio_zone(folio)) 2943630e7c5eSKefeng Wang goto next; 2944630e7c5eSKefeng Wang 2945630e7c5eSKefeng Wang if (!folio_test_large(folio) 2946630e7c5eSKefeng Wang || folio_test_hugetlb(folio) 2947630e7c5eSKefeng Wang || !folio_test_lru(folio)) 294849071d43SKirill A. Shutemov goto next; 294949071d43SKirill A. Shutemov 295049071d43SKirill A. Shutemov total++; 2951630e7c5eSKefeng Wang folio_lock(folio); 2952630e7c5eSKefeng Wang nr_pages = folio_nr_pages(folio); 2953630e7c5eSKefeng Wang if (!split_folio(folio)) 295449071d43SKirill A. Shutemov split++; 2955a17206daSMiaohe Lin pfn += nr_pages - 1; 2956630e7c5eSKefeng Wang folio_unlock(folio); 295749071d43SKirill A. Shutemov next: 2958630e7c5eSKefeng Wang folio_put(folio); 2959fa6c0231SZi Yan cond_resched(); 296049071d43SKirill A. Shutemov } 296149071d43SKirill A. Shutemov } 296249071d43SKirill A. Shutemov 2963fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 296449071d43SKirill A. Shutemov } 2965fa6c0231SZi Yan 2966fa6c0231SZi Yan static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) 2967fa6c0231SZi Yan { 2968fa6c0231SZi Yan return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || 2969fa6c0231SZi Yan is_vm_hugetlb_page(vma); 2970fa6c0231SZi Yan } 2971fa6c0231SZi Yan 2972fa6c0231SZi Yan static int split_huge_pages_pid(int pid, unsigned long vaddr_start, 2973fa6c0231SZi Yan unsigned long vaddr_end) 2974fa6c0231SZi Yan { 2975fa6c0231SZi Yan int ret = 0; 2976fa6c0231SZi Yan struct task_struct *task; 2977fa6c0231SZi Yan struct mm_struct *mm; 2978fa6c0231SZi Yan unsigned long total = 0, split = 0; 2979fa6c0231SZi Yan unsigned long addr; 2980fa6c0231SZi Yan 2981fa6c0231SZi Yan vaddr_start &= PAGE_MASK; 2982fa6c0231SZi Yan vaddr_end &= PAGE_MASK; 2983fa6c0231SZi Yan 2984fa6c0231SZi Yan /* Find the task_struct from pid */ 2985fa6c0231SZi Yan rcu_read_lock(); 2986fa6c0231SZi Yan task = find_task_by_vpid(pid); 2987fa6c0231SZi Yan if (!task) { 2988fa6c0231SZi Yan rcu_read_unlock(); 2989fa6c0231SZi Yan ret = -ESRCH; 2990fa6c0231SZi Yan goto out; 2991fa6c0231SZi Yan } 2992fa6c0231SZi Yan get_task_struct(task); 2993fa6c0231SZi Yan rcu_read_unlock(); 2994fa6c0231SZi Yan 2995fa6c0231SZi Yan /* Find the mm_struct */ 2996fa6c0231SZi Yan mm = get_task_mm(task); 2997fa6c0231SZi Yan put_task_struct(task); 2998fa6c0231SZi Yan 2999fa6c0231SZi Yan if (!mm) { 3000fa6c0231SZi Yan ret = -EINVAL; 3001fa6c0231SZi Yan goto out; 3002fa6c0231SZi Yan } 3003fa6c0231SZi Yan 3004fa6c0231SZi Yan pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", 3005fa6c0231SZi Yan pid, vaddr_start, vaddr_end); 3006fa6c0231SZi Yan 3007fa6c0231SZi Yan mmap_read_lock(mm); 3008fa6c0231SZi Yan /* 3009fa6c0231SZi Yan * always increase addr by PAGE_SIZE, since we could have a PTE page 3010fa6c0231SZi Yan * table filled with PTE-mapped THPs, each of which is distinct. 3011fa6c0231SZi Yan */ 3012fa6c0231SZi Yan for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { 301374ba2b38SMiaohe Lin struct vm_area_struct *vma = vma_lookup(mm, addr); 3014fa6c0231SZi Yan struct page *page; 3015fa6c0231SZi Yan 301674ba2b38SMiaohe Lin if (!vma) 3017fa6c0231SZi Yan break; 3018fa6c0231SZi Yan 3019fa6c0231SZi Yan /* skip special VMA and hugetlb VMA */ 3020fa6c0231SZi Yan if (vma_not_suitable_for_thp_split(vma)) { 3021fa6c0231SZi Yan addr = vma->vm_end; 3022fa6c0231SZi Yan continue; 3023fa6c0231SZi Yan } 3024fa6c0231SZi Yan 3025fa6c0231SZi Yan /* FOLL_DUMP to ignore special (like zero) pages */ 302687d2762eSMiaohe Lin page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); 3027fa6c0231SZi Yan 3028f7091ed6SHaiyue Wang if (IS_ERR_OR_NULL(page)) 3029fa6c0231SZi Yan continue; 3030fa6c0231SZi Yan 3031fa6c0231SZi Yan if (!is_transparent_hugepage(page)) 3032fa6c0231SZi Yan goto next; 3033fa6c0231SZi Yan 3034fa6c0231SZi Yan total++; 3035d4b4084aSMatthew Wilcox (Oracle) if (!can_split_folio(page_folio(page), NULL)) 3036fa6c0231SZi Yan goto next; 3037fa6c0231SZi Yan 3038fa6c0231SZi Yan if (!trylock_page(page)) 3039fa6c0231SZi Yan goto next; 3040fa6c0231SZi Yan 3041fa6c0231SZi Yan if (!split_huge_page(page)) 3042fa6c0231SZi Yan split++; 3043fa6c0231SZi Yan 3044fa6c0231SZi Yan unlock_page(page); 3045fa6c0231SZi Yan next: 3046fa6c0231SZi Yan put_page(page); 3047fa6c0231SZi Yan cond_resched(); 3048fa6c0231SZi Yan } 3049fa6c0231SZi Yan mmap_read_unlock(mm); 3050fa6c0231SZi Yan mmput(mm); 3051fa6c0231SZi Yan 3052fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 3053fa6c0231SZi Yan 3054fa6c0231SZi Yan out: 3055fa6c0231SZi Yan return ret; 3056fa6c0231SZi Yan } 3057fa6c0231SZi Yan 3058fbe37501SZi Yan static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, 3059fbe37501SZi Yan pgoff_t off_end) 3060fbe37501SZi Yan { 3061fbe37501SZi Yan struct filename *file; 3062fbe37501SZi Yan struct file *candidate; 3063fbe37501SZi Yan struct address_space *mapping; 3064fbe37501SZi Yan int ret = -EINVAL; 3065fbe37501SZi Yan pgoff_t index; 3066fbe37501SZi Yan int nr_pages = 1; 3067fbe37501SZi Yan unsigned long total = 0, split = 0; 3068fbe37501SZi Yan 3069fbe37501SZi Yan file = getname_kernel(file_path); 3070fbe37501SZi Yan if (IS_ERR(file)) 3071fbe37501SZi Yan return ret; 3072fbe37501SZi Yan 3073fbe37501SZi Yan candidate = file_open_name(file, O_RDONLY, 0); 3074fbe37501SZi Yan if (IS_ERR(candidate)) 3075fbe37501SZi Yan goto out; 3076fbe37501SZi Yan 3077fbe37501SZi Yan pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", 3078fbe37501SZi Yan file_path, off_start, off_end); 3079fbe37501SZi Yan 3080fbe37501SZi Yan mapping = candidate->f_mapping; 3081fbe37501SZi Yan 3082fbe37501SZi Yan for (index = off_start; index < off_end; index += nr_pages) { 30831fb130b2SChristoph Hellwig struct folio *folio = filemap_get_folio(mapping, index); 3084fbe37501SZi Yan 3085fbe37501SZi Yan nr_pages = 1; 308666dabbb6SChristoph Hellwig if (IS_ERR(folio)) 3087fbe37501SZi Yan continue; 3088fbe37501SZi Yan 30899ee2c086SMatthew Wilcox (Oracle) if (!folio_test_large(folio)) 3090fbe37501SZi Yan goto next; 3091fbe37501SZi Yan 3092fbe37501SZi Yan total++; 30939ee2c086SMatthew Wilcox (Oracle) nr_pages = folio_nr_pages(folio); 3094fbe37501SZi Yan 30959ee2c086SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 3096fbe37501SZi Yan goto next; 3097fbe37501SZi Yan 30989ee2c086SMatthew Wilcox (Oracle) if (!split_folio(folio)) 3099fbe37501SZi Yan split++; 3100fbe37501SZi Yan 31019ee2c086SMatthew Wilcox (Oracle) folio_unlock(folio); 3102fbe37501SZi Yan next: 31039ee2c086SMatthew Wilcox (Oracle) folio_put(folio); 3104fbe37501SZi Yan cond_resched(); 3105fbe37501SZi Yan } 3106fbe37501SZi Yan 3107fbe37501SZi Yan filp_close(candidate, NULL); 3108fbe37501SZi Yan ret = 0; 3109fbe37501SZi Yan 3110fbe37501SZi Yan pr_debug("%lu of %lu file-backed THP split\n", split, total); 3111fbe37501SZi Yan out: 3112fbe37501SZi Yan putname(file); 3113fbe37501SZi Yan return ret; 3114fbe37501SZi Yan } 3115fbe37501SZi Yan 3116fa6c0231SZi Yan #define MAX_INPUT_BUF_SZ 255 3117fa6c0231SZi Yan 3118fa6c0231SZi Yan static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, 3119fa6c0231SZi Yan size_t count, loff_t *ppops) 3120fa6c0231SZi Yan { 3121fa6c0231SZi Yan static DEFINE_MUTEX(split_debug_mutex); 3122fa6c0231SZi Yan ssize_t ret; 3123fbe37501SZi Yan /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ 3124fbe37501SZi Yan char input_buf[MAX_INPUT_BUF_SZ]; 3125fa6c0231SZi Yan int pid; 3126fa6c0231SZi Yan unsigned long vaddr_start, vaddr_end; 3127fa6c0231SZi Yan 3128fa6c0231SZi Yan ret = mutex_lock_interruptible(&split_debug_mutex); 3129fa6c0231SZi Yan if (ret) 3130fa6c0231SZi Yan return ret; 3131fa6c0231SZi Yan 3132fa6c0231SZi Yan ret = -EFAULT; 3133fa6c0231SZi Yan 3134fa6c0231SZi Yan memset(input_buf, 0, MAX_INPUT_BUF_SZ); 3135fa6c0231SZi Yan if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) 3136fa6c0231SZi Yan goto out; 3137fa6c0231SZi Yan 3138fa6c0231SZi Yan input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; 3139fbe37501SZi Yan 3140fbe37501SZi Yan if (input_buf[0] == '/') { 3141fbe37501SZi Yan char *tok; 3142fbe37501SZi Yan char *buf = input_buf; 3143fbe37501SZi Yan char file_path[MAX_INPUT_BUF_SZ]; 3144fbe37501SZi Yan pgoff_t off_start = 0, off_end = 0; 3145fbe37501SZi Yan size_t input_len = strlen(input_buf); 3146fbe37501SZi Yan 3147fbe37501SZi Yan tok = strsep(&buf, ","); 3148fbe37501SZi Yan if (tok) { 31491212e00cSMatthew Wilcox (Oracle) strcpy(file_path, tok); 3150fbe37501SZi Yan } else { 3151fbe37501SZi Yan ret = -EINVAL; 3152fbe37501SZi Yan goto out; 3153fbe37501SZi Yan } 3154fbe37501SZi Yan 3155fbe37501SZi Yan ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); 3156fbe37501SZi Yan if (ret != 2) { 3157fbe37501SZi Yan ret = -EINVAL; 3158fbe37501SZi Yan goto out; 3159fbe37501SZi Yan } 3160fbe37501SZi Yan ret = split_huge_pages_in_file(file_path, off_start, off_end); 3161fbe37501SZi Yan if (!ret) 3162fbe37501SZi Yan ret = input_len; 3163fbe37501SZi Yan 3164fbe37501SZi Yan goto out; 3165fbe37501SZi Yan } 3166fbe37501SZi Yan 3167fa6c0231SZi Yan ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); 3168fa6c0231SZi Yan if (ret == 1 && pid == 1) { 3169fa6c0231SZi Yan split_huge_pages_all(); 3170fa6c0231SZi Yan ret = strlen(input_buf); 3171fa6c0231SZi Yan goto out; 3172fa6c0231SZi Yan } else if (ret != 3) { 3173fa6c0231SZi Yan ret = -EINVAL; 3174fa6c0231SZi Yan goto out; 3175fa6c0231SZi Yan } 3176fa6c0231SZi Yan 3177fa6c0231SZi Yan ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); 3178fa6c0231SZi Yan if (!ret) 3179fa6c0231SZi Yan ret = strlen(input_buf); 3180fa6c0231SZi Yan out: 3181fa6c0231SZi Yan mutex_unlock(&split_debug_mutex); 3182fa6c0231SZi Yan return ret; 3183fa6c0231SZi Yan 3184fa6c0231SZi Yan } 3185fa6c0231SZi Yan 3186fa6c0231SZi Yan static const struct file_operations split_huge_pages_fops = { 3187fa6c0231SZi Yan .owner = THIS_MODULE, 3188fa6c0231SZi Yan .write = split_huge_pages_write, 3189fa6c0231SZi Yan .llseek = no_llseek, 3190fa6c0231SZi Yan }; 319149071d43SKirill A. Shutemov 319249071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 319349071d43SKirill A. Shutemov { 3194d9f7979cSGreg Kroah-Hartman debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 319549071d43SKirill A. Shutemov &split_huge_pages_fops); 319649071d43SKirill A. Shutemov return 0; 319749071d43SKirill A. Shutemov } 319849071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 319949071d43SKirill A. Shutemov #endif 3200616b8371SZi Yan 3201616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 32027f5abe60SDavid Hildenbrand int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 3203616b8371SZi Yan struct page *page) 3204616b8371SZi Yan { 3205616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3206616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3207616b8371SZi Yan unsigned long address = pvmw->address; 32086c287605SDavid Hildenbrand bool anon_exclusive; 3209616b8371SZi Yan pmd_t pmdval; 3210616b8371SZi Yan swp_entry_t entry; 3211ab6e3d09SNaoya Horiguchi pmd_t pmdswp; 3212616b8371SZi Yan 3213616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 32147f5abe60SDavid Hildenbrand return 0; 3215616b8371SZi Yan 3216616b8371SZi Yan flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); 32178a8683adSHuang Ying pmdval = pmdp_invalidate(vma, address, pvmw->pmd); 32186c287605SDavid Hildenbrand 3219088b8aa5SDavid Hildenbrand /* See page_try_share_anon_rmap(): invalidate PMD first. */ 32206c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 32216c287605SDavid Hildenbrand if (anon_exclusive && page_try_share_anon_rmap(page)) { 32226c287605SDavid Hildenbrand set_pmd_at(mm, address, pvmw->pmd, pmdval); 32237f5abe60SDavid Hildenbrand return -EBUSY; 32246c287605SDavid Hildenbrand } 32256c287605SDavid Hildenbrand 3226616b8371SZi Yan if (pmd_dirty(pmdval)) 3227616b8371SZi Yan set_page_dirty(page); 32284dd845b5SAlistair Popple if (pmd_write(pmdval)) 32294dd845b5SAlistair Popple entry = make_writable_migration_entry(page_to_pfn(page)); 32306c287605SDavid Hildenbrand else if (anon_exclusive) 32316c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); 32324dd845b5SAlistair Popple else 32334dd845b5SAlistair Popple entry = make_readable_migration_entry(page_to_pfn(page)); 32342e346877SPeter Xu if (pmd_young(pmdval)) 32352e346877SPeter Xu entry = make_migration_entry_young(entry); 32362e346877SPeter Xu if (pmd_dirty(pmdval)) 32372e346877SPeter Xu entry = make_migration_entry_dirty(entry); 3238ab6e3d09SNaoya Horiguchi pmdswp = swp_entry_to_pmd(entry); 3239ab6e3d09SNaoya Horiguchi if (pmd_soft_dirty(pmdval)) 3240ab6e3d09SNaoya Horiguchi pmdswp = pmd_swp_mksoft_dirty(pmdswp); 324124bf08c4SDavid Hildenbrand if (pmd_uffd_wp(pmdval)) 324224bf08c4SDavid Hildenbrand pmdswp = pmd_swp_mkuffd_wp(pmdswp); 3243ab6e3d09SNaoya Horiguchi set_pmd_at(mm, address, pvmw->pmd, pmdswp); 3244cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 3245616b8371SZi Yan put_page(page); 3246283fd6feSAnshuman Khandual trace_set_migration_pmd(address, pmd_val(pmdswp)); 32477f5abe60SDavid Hildenbrand 32487f5abe60SDavid Hildenbrand return 0; 3249616b8371SZi Yan } 3250616b8371SZi Yan 3251616b8371SZi Yan void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 3252616b8371SZi Yan { 3253616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3254616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3255616b8371SZi Yan unsigned long address = pvmw->address; 32564fba8f2aSMiaohe Lin unsigned long haddr = address & HPAGE_PMD_MASK; 3257616b8371SZi Yan pmd_t pmde; 3258616b8371SZi Yan swp_entry_t entry; 3259616b8371SZi Yan 3260616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 3261616b8371SZi Yan return; 3262616b8371SZi Yan 3263616b8371SZi Yan entry = pmd_to_swp_entry(*pvmw->pmd); 3264616b8371SZi Yan get_page(new); 32652e346877SPeter Xu pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); 3266ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pvmw->pmd)) 3267ab6e3d09SNaoya Horiguchi pmde = pmd_mksoft_dirty(pmde); 32683c811f78SDavid Hildenbrand if (is_writable_migration_entry(entry)) 3269f3ebdf04SDavid Hildenbrand pmde = pmd_mkwrite(pmde); 32708f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*pvmw->pmd)) 3271f1eb1bacSPeter Xu pmde = pmd_mkuffd_wp(pmde); 32722e346877SPeter Xu if (!is_migration_entry_young(entry)) 32732e346877SPeter Xu pmde = pmd_mkold(pmde); 32742e346877SPeter Xu /* NOTE: this may contain setting soft-dirty on some archs */ 32752e346877SPeter Xu if (PageDirty(new) && is_migration_entry_dirty(entry)) 32762e346877SPeter Xu pmde = pmd_mkdirty(pmde); 3277616b8371SZi Yan 32786c287605SDavid Hildenbrand if (PageAnon(new)) { 32796c287605SDavid Hildenbrand rmap_t rmap_flags = RMAP_COMPOUND; 32806c287605SDavid Hildenbrand 32816c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) 32826c287605SDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 32836c287605SDavid Hildenbrand 32844fba8f2aSMiaohe Lin page_add_anon_rmap(new, vma, haddr, rmap_flags); 32856c287605SDavid Hildenbrand } else { 3286cea86fe2SHugh Dickins page_add_file_rmap(new, vma, true); 32876c287605SDavid Hildenbrand } 32886c287605SDavid Hildenbrand VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); 32894fba8f2aSMiaohe Lin set_pmd_at(mm, haddr, pvmw->pmd, pmde); 32905cbcf225SMuchun Song 32915cbcf225SMuchun Song /* No need to invalidate - it was non-present before */ 3292616b8371SZi Yan update_mmu_cache_pmd(vma, address, pvmw->pmd); 3293283fd6feSAnshuman Khandual trace_remove_migration_pmd(address, pmd_val(pmde)); 3294616b8371SZi Yan } 3295616b8371SZi Yan #endif 3296