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> 214897c765SMatthew Wilcox #include <linux/dax.h> 22ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 23878aee7dSAndrea Arcangeli #include <linux/freezer.h> 24f25748e3SDan Williams #include <linux/pfn_t.h> 25a664b2d8SAndrea Arcangeli #include <linux/mman.h> 263565fce3SDan Williams #include <linux/memremap.h> 27325adeb5SRalf Baechle #include <linux/pagemap.h> 2849071d43SKirill A. Shutemov #include <linux/debugfs.h> 294daae3b4SMel Gorman #include <linux/migrate.h> 3043b5fbbdSSasha Levin #include <linux/hashtable.h> 316b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 3233c3fc71SVladimir Davydov #include <linux/page_idle.h> 33baa355fdSKirill A. Shutemov #include <linux/shmem_fs.h> 346b31d595SMichal Hocko #include <linux/oom.h> 3598fa15f3SAnshuman Khandual #include <linux/numa.h> 36f7da677bSVlastimil Babka #include <linux/page_owner.h> 37a1a3a2fcSHuang Ying #include <linux/sched/sysctl.h> 3897ae1749SKirill A. Shutemov 3971e3aac0SAndrea Arcangeli #include <asm/tlb.h> 4071e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 4171e3aac0SAndrea Arcangeli #include "internal.h" 42014bb1deSNeilBrown #include "swap.h" 4371e3aac0SAndrea Arcangeli 44283fd6feSAnshuman Khandual #define CREATE_TRACE_POINTS 45283fd6feSAnshuman Khandual #include <trace/events/thp.h> 46283fd6feSAnshuman Khandual 47ba76149fSAndrea Arcangeli /* 48b14d595aSMichael DeGuzis * By default, transparent hugepage support is disabled in order to avoid 49b14d595aSMichael DeGuzis * risking an increased memory footprint for applications that are not 50b14d595aSMichael DeGuzis * guaranteed to benefit from it. When transparent hugepage support is 51b14d595aSMichael DeGuzis * enabled, it is for all mappings, and khugepaged scans all mappings. 528bfa3f9aSJianguo Wu * Defrag is invoked by khugepaged hugepage allocations and by page faults 538bfa3f9aSJianguo Wu * for all hugepage allocations. 54ba76149fSAndrea Arcangeli */ 5571e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 5613ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 57ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 5813ece886SAndrea Arcangeli #endif 5913ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 6013ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 6113ece886SAndrea Arcangeli #endif 62444eb2a4SMel Gorman (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| 6379da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 6479da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 65ba76149fSAndrea Arcangeli 669a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker; 67f000565aSAndrea Arcangeli 6897ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 6956873f43SWang, Yalin struct page *huge_zero_page __read_mostly; 703b77e8c8SHugh Dickins unsigned long huge_zero_pfn __read_mostly = ~0UL; 714a6c1297SKirill A. Shutemov 729fec5168SYang Shi bool hugepage_vma_check(struct vm_area_struct *vma, 739fec5168SYang Shi unsigned long vm_flags, 747da4e2cbSYang Shi bool smaps, bool in_pf) 757635d9cbSMichal Hocko { 769fec5168SYang Shi if (!vma->vm_mm) /* vdso */ 77c0630669SYang Shi return false; 789fec5168SYang Shi 797da4e2cbSYang Shi /* 807da4e2cbSYang Shi * Explicitly disabled through madvise or prctl, or some 817da4e2cbSYang Shi * architectures may disable THP for some mappings, for 827da4e2cbSYang Shi * example, s390 kvm. 837da4e2cbSYang Shi * */ 847da4e2cbSYang Shi if ((vm_flags & VM_NOHUGEPAGE) || 857da4e2cbSYang Shi test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) 867da4e2cbSYang Shi return false; 877da4e2cbSYang Shi /* 887da4e2cbSYang Shi * If the hardware/firmware marked hugepage support disabled. 897da4e2cbSYang Shi */ 907da4e2cbSYang Shi if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX)) 919fec5168SYang Shi return false; 929fec5168SYang Shi 937da4e2cbSYang Shi /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ 947da4e2cbSYang Shi if (vma_is_dax(vma)) 957da4e2cbSYang Shi return in_pf; 967da4e2cbSYang Shi 977da4e2cbSYang Shi /* 987da4e2cbSYang Shi * Special VMA and hugetlb VMA. 997da4e2cbSYang Shi * Must be checked after dax since some dax mappings may have 1007da4e2cbSYang Shi * VM_MIXEDMAP set. 1017da4e2cbSYang Shi */ 1029fec5168SYang Shi if (vm_flags & VM_NO_KHUGEPAGED) 1039fec5168SYang Shi return false; 1049fec5168SYang Shi 1057da4e2cbSYang Shi /* 1067da4e2cbSYang Shi * Check alignment for file vma and size for both file and anon vma. 1077da4e2cbSYang Shi * 1087da4e2cbSYang Shi * Skip the check for page fault. Huge fault does the check in fault 1097da4e2cbSYang Shi * handlers. And this check is not suitable for huge PUD fault. 1107da4e2cbSYang Shi */ 1117da4e2cbSYang Shi if (!in_pf && 1127da4e2cbSYang Shi !transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE))) 1139fec5168SYang Shi return false; 1149fec5168SYang Shi 1157da4e2cbSYang Shi /* 1167da4e2cbSYang Shi * Enabled via shmem mount options or sysfs settings. 1177da4e2cbSYang Shi * Must be done before hugepage flags check since shmem has its 1187da4e2cbSYang Shi * own flags. 1197da4e2cbSYang Shi */ 1207da4e2cbSYang Shi if (!in_pf && shmem_file(vma->vm_file)) 121c0630669SYang Shi return shmem_huge_enabled(vma); 1229fec5168SYang Shi 1231064026bSYang Shi if (!hugepage_flags_enabled()) 1249fec5168SYang Shi return false; 1259fec5168SYang Shi 1269fec5168SYang Shi /* THP settings require madvise. */ 1271064026bSYang Shi if (!(vm_flags & VM_HUGEPAGE) && !hugepage_flags_always()) 1289fec5168SYang Shi return false; 1299fec5168SYang Shi 1309fec5168SYang Shi /* Only regular file is valid */ 1317da4e2cbSYang Shi if (!in_pf && file_thp_enabled(vma)) 13278d12c19SYang Shi return true; 1337635d9cbSMichal Hocko 1349fec5168SYang Shi if (!vma_is_anonymous(vma)) 1357635d9cbSMichal Hocko return false; 1369fec5168SYang Shi 1379fec5168SYang Shi if (vma_is_temporary_stack(vma)) 1389fec5168SYang Shi return false; 1399fec5168SYang Shi 1409fec5168SYang Shi /* 1419fec5168SYang Shi * THPeligible bit of smaps should show 1 for proper VMAs even 1429fec5168SYang Shi * though anon_vma is not initialized yet. 1437da4e2cbSYang Shi * 1447da4e2cbSYang Shi * Allow page fault since anon_vma may be not initialized until 1457da4e2cbSYang Shi * the first page fault. 1469fec5168SYang Shi */ 1479fec5168SYang Shi if (!vma->anon_vma) 1487da4e2cbSYang Shi return (smaps || in_pf); 1499fec5168SYang Shi 1509fec5168SYang Shi return true; 1517635d9cbSMichal Hocko } 1527635d9cbSMichal Hocko 153aaa9705bSMiaohe Lin static bool get_huge_zero_page(void) 15497ae1749SKirill A. Shutemov { 15597ae1749SKirill A. Shutemov struct page *zero_page; 15697ae1749SKirill A. Shutemov retry: 15797ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 158aaa9705bSMiaohe Lin return true; 15997ae1749SKirill A. Shutemov 16097ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 16197ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 162d8a8e1f0SKirill A. Shutemov if (!zero_page) { 163d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 164aaa9705bSMiaohe Lin return false; 165d8a8e1f0SKirill A. Shutemov } 166d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC); 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(); 178aaa9705bSMiaohe Lin return true; 17997ae1749SKirill A. Shutemov } 18097ae1749SKirill A. Shutemov 1816fcb52a5SAaron Lu static void put_huge_zero_page(void) 18297ae1749SKirill A. Shutemov { 18397ae1749SKirill A. Shutemov /* 18497ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 18597ae1749SKirill A. Shutemov * last reference. 18697ae1749SKirill A. Shutemov */ 18797ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 18897ae1749SKirill A. Shutemov } 18997ae1749SKirill A. Shutemov 1906fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 1916fcb52a5SAaron Lu { 1926fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1936fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 1946fcb52a5SAaron Lu 1956fcb52a5SAaron Lu if (!get_huge_zero_page()) 1966fcb52a5SAaron Lu return NULL; 1976fcb52a5SAaron Lu 1986fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 1996fcb52a5SAaron Lu put_huge_zero_page(); 2006fcb52a5SAaron Lu 2016fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 2026fcb52a5SAaron Lu } 2036fcb52a5SAaron Lu 2046fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 2056fcb52a5SAaron Lu { 2066fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2076fcb52a5SAaron Lu put_huge_zero_page(); 2086fcb52a5SAaron Lu } 2096fcb52a5SAaron Lu 21048896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 21197ae1749SKirill A. Shutemov struct shrink_control *sc) 21297ae1749SKirill A. Shutemov { 21397ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 21497ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 21548896466SGlauber Costa } 21697ae1749SKirill A. Shutemov 21748896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 21848896466SGlauber Costa struct shrink_control *sc) 21948896466SGlauber Costa { 22097ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2215918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2225918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2233b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, ~0UL); 2245ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 22548896466SGlauber Costa return HPAGE_PMD_NR; 22697ae1749SKirill A. Shutemov } 22797ae1749SKirill A. Shutemov 22897ae1749SKirill A. Shutemov return 0; 22997ae1749SKirill A. Shutemov } 23097ae1749SKirill A. Shutemov 23197ae1749SKirill A. Shutemov static struct shrinker huge_zero_page_shrinker = { 23248896466SGlauber Costa .count_objects = shrink_huge_zero_page_count, 23348896466SGlauber Costa .scan_objects = shrink_huge_zero_page_scan, 23497ae1749SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 23597ae1749SKirill A. Shutemov }; 23697ae1749SKirill A. Shutemov 23771e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 23871e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 23971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 24071e3aac0SAndrea Arcangeli { 241bfb0ffebSJoe Perches const char *output; 242bfb0ffebSJoe Perches 243444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 244bfb0ffebSJoe Perches output = "[always] madvise never"; 245bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 246bfb0ffebSJoe Perches &transparent_hugepage_flags)) 247bfb0ffebSJoe Perches output = "always [madvise] never"; 248444eb2a4SMel Gorman else 249bfb0ffebSJoe Perches output = "always madvise [never]"; 250bfb0ffebSJoe Perches 251bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 25271e3aac0SAndrea Arcangeli } 253444eb2a4SMel Gorman 25471e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 25571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 25671e3aac0SAndrea Arcangeli const char *buf, size_t count) 25771e3aac0SAndrea Arcangeli { 25821440d7eSDavid Rientjes ssize_t ret = count; 259ba76149fSAndrea Arcangeli 260f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 26121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 26221440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 263f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 26421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 26521440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 266f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 26721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 26821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 26921440d7eSDavid Rientjes } else 27021440d7eSDavid Rientjes ret = -EINVAL; 271ba76149fSAndrea Arcangeli 272ba76149fSAndrea Arcangeli if (ret > 0) { 273b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 274ba76149fSAndrea Arcangeli if (err) 275ba76149fSAndrea Arcangeli ret = err; 276ba76149fSAndrea Arcangeli } 277ba76149fSAndrea Arcangeli return ret; 27871e3aac0SAndrea Arcangeli } 27937139bb0SMiaohe Lin 28037139bb0SMiaohe Lin static struct kobj_attribute enabled_attr = __ATTR_RW(enabled); 28171e3aac0SAndrea Arcangeli 282b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 28371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 28471e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 28571e3aac0SAndrea Arcangeli { 286bfb0ffebSJoe Perches return sysfs_emit(buf, "%d\n", 287e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 28871e3aac0SAndrea Arcangeli } 289e27e6151SBen Hutchings 290b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 29171e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 29271e3aac0SAndrea Arcangeli const char *buf, size_t count, 29371e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 29471e3aac0SAndrea Arcangeli { 295e27e6151SBen Hutchings unsigned long value; 296e27e6151SBen Hutchings int ret; 297e27e6151SBen Hutchings 298e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 299e27e6151SBen Hutchings if (ret < 0) 300e27e6151SBen Hutchings return ret; 301e27e6151SBen Hutchings if (value > 1) 30271e3aac0SAndrea Arcangeli return -EINVAL; 30371e3aac0SAndrea Arcangeli 304e27e6151SBen Hutchings if (value) 305e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 306e27e6151SBen Hutchings else 307e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 308e27e6151SBen Hutchings 30971e3aac0SAndrea Arcangeli return count; 31071e3aac0SAndrea Arcangeli } 31171e3aac0SAndrea Arcangeli 31271e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 31371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 31471e3aac0SAndrea Arcangeli { 315bfb0ffebSJoe Perches const char *output; 316bfb0ffebSJoe Perches 317bfb0ffebSJoe Perches if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, 318bfb0ffebSJoe Perches &transparent_hugepage_flags)) 319bfb0ffebSJoe Perches output = "[always] defer defer+madvise madvise never"; 320bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, 321bfb0ffebSJoe Perches &transparent_hugepage_flags)) 322bfb0ffebSJoe Perches output = "always [defer] defer+madvise madvise never"; 323bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, 324bfb0ffebSJoe Perches &transparent_hugepage_flags)) 325bfb0ffebSJoe Perches output = "always defer [defer+madvise] madvise never"; 326bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, 327bfb0ffebSJoe Perches &transparent_hugepage_flags)) 328bfb0ffebSJoe Perches output = "always defer defer+madvise [madvise] never"; 329bfb0ffebSJoe Perches else 330bfb0ffebSJoe Perches output = "always defer defer+madvise madvise [never]"; 331bfb0ffebSJoe Perches 332bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 33371e3aac0SAndrea Arcangeli } 33421440d7eSDavid Rientjes 33571e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 33671e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 33771e3aac0SAndrea Arcangeli const char *buf, size_t count) 33871e3aac0SAndrea Arcangeli { 339f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 34021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 34121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 34221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 34321440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 344f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer+madvise")) { 34521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 34621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 34721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 34821440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 349f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer")) { 3504fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 3514fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 3524fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 3534fad7fb6SDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 354f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 35521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 35621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 35721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 35821440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 359f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 36021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 36121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 36221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 36321440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 36421440d7eSDavid Rientjes } else 36521440d7eSDavid Rientjes return -EINVAL; 36621440d7eSDavid Rientjes 36721440d7eSDavid Rientjes return count; 36871e3aac0SAndrea Arcangeli } 36937139bb0SMiaohe Lin static struct kobj_attribute defrag_attr = __ATTR_RW(defrag); 37071e3aac0SAndrea Arcangeli 37179da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 37279da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 37379da5407SKirill A. Shutemov { 374b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 37579da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 37679da5407SKirill A. Shutemov } 37779da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 37879da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 37979da5407SKirill A. Shutemov { 380b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 38179da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 38279da5407SKirill A. Shutemov } 38337139bb0SMiaohe Lin static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page); 38449920d28SHugh Dickins 38549920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 38649920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 38749920d28SHugh Dickins { 388ae7a927dSJoe Perches return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); 38949920d28SHugh Dickins } 39049920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 39149920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 39249920d28SHugh Dickins 39371e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 39471e3aac0SAndrea Arcangeli &enabled_attr.attr, 39571e3aac0SAndrea Arcangeli &defrag_attr.attr, 39679da5407SKirill A. Shutemov &use_zero_page_attr.attr, 39749920d28SHugh Dickins &hpage_pmd_size_attr.attr, 398396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_SHMEM 3995a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 4005a6e75f8SKirill A. Shutemov #endif 40171e3aac0SAndrea Arcangeli NULL, 40271e3aac0SAndrea Arcangeli }; 40371e3aac0SAndrea Arcangeli 4048aa95a21SArvind Yadav static const struct attribute_group hugepage_attr_group = { 40571e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 406ba76149fSAndrea Arcangeli }; 407ba76149fSAndrea Arcangeli 408569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 409569e5590SShaohua Li { 410569e5590SShaohua Li int err; 411569e5590SShaohua Li 412569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 413569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 414ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 415569e5590SShaohua Li return -ENOMEM; 416569e5590SShaohua Li } 417569e5590SShaohua Li 418569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 419569e5590SShaohua Li if (err) { 420ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 421569e5590SShaohua Li goto delete_obj; 422569e5590SShaohua Li } 423569e5590SShaohua Li 424569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 425569e5590SShaohua Li if (err) { 426ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 427569e5590SShaohua Li goto remove_hp_group; 428569e5590SShaohua Li } 429569e5590SShaohua Li 430569e5590SShaohua Li return 0; 431569e5590SShaohua Li 432569e5590SShaohua Li remove_hp_group: 433569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 434569e5590SShaohua Li delete_obj: 435569e5590SShaohua Li kobject_put(*hugepage_kobj); 436569e5590SShaohua Li return err; 437569e5590SShaohua Li } 438569e5590SShaohua Li 439569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 440569e5590SShaohua Li { 441569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 442569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 443569e5590SShaohua Li kobject_put(hugepage_kobj); 444569e5590SShaohua Li } 445569e5590SShaohua Li #else 446569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 447569e5590SShaohua Li { 448569e5590SShaohua Li return 0; 449569e5590SShaohua Li } 450569e5590SShaohua Li 451569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 452569e5590SShaohua Li { 453569e5590SShaohua Li } 45471e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 45571e3aac0SAndrea Arcangeli 45671e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 45771e3aac0SAndrea Arcangeli { 45871e3aac0SAndrea Arcangeli int err; 459569e5590SShaohua Li struct kobject *hugepage_kobj; 46071e3aac0SAndrea Arcangeli 4614b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 462bae84953SAneesh Kumar K.V /* 463bae84953SAneesh Kumar K.V * Hardware doesn't support hugepages, hence disable 464bae84953SAneesh Kumar K.V * DAX PMD support. 465bae84953SAneesh Kumar K.V */ 466bae84953SAneesh Kumar K.V transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX; 467569e5590SShaohua Li return -EINVAL; 4684b7167b9SAndrea Arcangeli } 4694b7167b9SAndrea Arcangeli 470ff20c2e0SKirill A. Shutemov /* 471ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 472ff20c2e0SKirill A. Shutemov */ 473ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); 474ff20c2e0SKirill A. Shutemov /* 475ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 476ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 477ff20c2e0SKirill A. Shutemov */ 478ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 479ff20c2e0SKirill A. Shutemov 480569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 481569e5590SShaohua Li if (err) 48265ebb64fSKirill A. Shutemov goto err_sysfs; 483ba76149fSAndrea Arcangeli 484b46e756fSKirill A. Shutemov err = khugepaged_init(); 485ba76149fSAndrea Arcangeli if (err) 48665ebb64fSKirill A. Shutemov goto err_slab; 487ba76149fSAndrea Arcangeli 488e33c267aSRoman Gushchin err = register_shrinker(&huge_zero_page_shrinker, "thp-zero"); 48965ebb64fSKirill A. Shutemov if (err) 49065ebb64fSKirill A. Shutemov goto err_hzp_shrinker; 491e33c267aSRoman Gushchin err = register_shrinker(&deferred_split_shrinker, "thp-deferred_split"); 4929a982250SKirill A. Shutemov if (err) 4939a982250SKirill A. Shutemov goto err_split_shrinker; 49497ae1749SKirill A. Shutemov 49597562cd2SRik van Riel /* 49697562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 49797562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 49897562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 49997562cd2SRik van Riel */ 500ca79b0c2SArun KS if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { 50197562cd2SRik van Riel transparent_hugepage_flags = 0; 50279553da2SKirill A. Shutemov return 0; 50379553da2SKirill A. Shutemov } 50497562cd2SRik van Riel 50579553da2SKirill A. Shutemov err = start_stop_khugepaged(); 50665ebb64fSKirill A. Shutemov if (err) 50765ebb64fSKirill A. Shutemov goto err_khugepaged; 508ba76149fSAndrea Arcangeli 509569e5590SShaohua Li return 0; 51065ebb64fSKirill A. Shutemov err_khugepaged: 5119a982250SKirill A. Shutemov unregister_shrinker(&deferred_split_shrinker); 5129a982250SKirill A. Shutemov err_split_shrinker: 51365ebb64fSKirill A. Shutemov unregister_shrinker(&huge_zero_page_shrinker); 51465ebb64fSKirill A. Shutemov err_hzp_shrinker: 515b46e756fSKirill A. Shutemov khugepaged_destroy(); 51665ebb64fSKirill A. Shutemov err_slab: 517569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 51865ebb64fSKirill A. Shutemov err_sysfs: 519ba76149fSAndrea Arcangeli return err; 52071e3aac0SAndrea Arcangeli } 521a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 52271e3aac0SAndrea Arcangeli 52371e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 52471e3aac0SAndrea Arcangeli { 52571e3aac0SAndrea Arcangeli int ret = 0; 52671e3aac0SAndrea Arcangeli if (!str) 52771e3aac0SAndrea Arcangeli goto out; 52871e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 52971e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 53071e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53171e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 53271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53371e3aac0SAndrea Arcangeli ret = 1; 53471e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 53571e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 53671e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53771e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 53871e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 53971e3aac0SAndrea Arcangeli ret = 1; 54071e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 54171e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 54271e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 54371e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 54471e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 54571e3aac0SAndrea Arcangeli ret = 1; 54671e3aac0SAndrea Arcangeli } 54771e3aac0SAndrea Arcangeli out: 54871e3aac0SAndrea Arcangeli if (!ret) 549ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 55071e3aac0SAndrea Arcangeli return ret; 55171e3aac0SAndrea Arcangeli } 55271e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 55371e3aac0SAndrea Arcangeli 554f55e1014SLinus Torvalds pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 55571e3aac0SAndrea Arcangeli { 556f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 55771e3aac0SAndrea Arcangeli pmd = pmd_mkwrite(pmd); 55871e3aac0SAndrea Arcangeli return pmd; 55971e3aac0SAndrea Arcangeli } 56071e3aac0SAndrea Arcangeli 56187eaceb3SYang Shi #ifdef CONFIG_MEMCG 56287eaceb3SYang Shi static inline struct deferred_split *get_deferred_split_queue(struct page *page) 5639a982250SKirill A. Shutemov { 564bcfe06bfSRoman Gushchin struct mem_cgroup *memcg = page_memcg(compound_head(page)); 56587eaceb3SYang Shi struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); 56687eaceb3SYang Shi 56787eaceb3SYang Shi if (memcg) 56887eaceb3SYang Shi return &memcg->deferred_split_queue; 56987eaceb3SYang Shi else 57087eaceb3SYang Shi return &pgdat->deferred_split_queue; 5719a982250SKirill A. Shutemov } 57287eaceb3SYang Shi #else 57387eaceb3SYang Shi static inline struct deferred_split *get_deferred_split_queue(struct page *page) 57487eaceb3SYang Shi { 57587eaceb3SYang Shi struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); 57687eaceb3SYang Shi 57787eaceb3SYang Shi return &pgdat->deferred_split_queue; 57887eaceb3SYang Shi } 57987eaceb3SYang Shi #endif 5809a982250SKirill A. Shutemov 5819a982250SKirill A. Shutemov void prep_transhuge_page(struct page *page) 5829a982250SKirill A. Shutemov { 5839a982250SKirill A. Shutemov /* 5849a982250SKirill A. Shutemov * we use page->mapping and page->indexlru in second tail page 5859a982250SKirill A. Shutemov * as list_head: assuming THP order >= 2 5869a982250SKirill A. Shutemov */ 5879a982250SKirill A. Shutemov 5889a982250SKirill A. Shutemov INIT_LIST_HEAD(page_deferred_list(page)); 5899a982250SKirill A. Shutemov set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); 5909a982250SKirill A. Shutemov } 5919a982250SKirill A. Shutemov 592562beb72SMiaohe Lin static inline bool is_transparent_hugepage(struct page *page) 593005ba37cSSean Christopherson { 594005ba37cSSean Christopherson if (!PageCompound(page)) 595fa1f68ccSZou Wei return false; 596005ba37cSSean Christopherson 597005ba37cSSean Christopherson page = compound_head(page); 598005ba37cSSean Christopherson return is_huge_zero_page(page) || 599005ba37cSSean Christopherson page[1].compound_dtor == TRANSHUGE_PAGE_DTOR; 600005ba37cSSean Christopherson } 601005ba37cSSean Christopherson 60297d3d0f9SKirill A. Shutemov static unsigned long __thp_get_unmapped_area(struct file *filp, 60397d3d0f9SKirill A. Shutemov unsigned long addr, unsigned long len, 60474d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 60574d2fad1SToshi Kani { 60674d2fad1SToshi Kani loff_t off_end = off + len; 60774d2fad1SToshi Kani loff_t off_align = round_up(off, size); 60897d3d0f9SKirill A. Shutemov unsigned long len_pad, ret; 60974d2fad1SToshi Kani 61074d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 61174d2fad1SToshi Kani return 0; 61274d2fad1SToshi Kani 61374d2fad1SToshi Kani len_pad = len + size; 61474d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 61574d2fad1SToshi Kani return 0; 61674d2fad1SToshi Kani 61797d3d0f9SKirill A. Shutemov ret = current->mm->get_unmapped_area(filp, addr, len_pad, 61874d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 61997d3d0f9SKirill A. Shutemov 62097d3d0f9SKirill A. Shutemov /* 62197d3d0f9SKirill A. Shutemov * The failure might be due to length padding. The caller will retry 62297d3d0f9SKirill A. Shutemov * without the padding. 62397d3d0f9SKirill A. Shutemov */ 62497d3d0f9SKirill A. Shutemov if (IS_ERR_VALUE(ret)) 62574d2fad1SToshi Kani return 0; 62674d2fad1SToshi Kani 62797d3d0f9SKirill A. Shutemov /* 62897d3d0f9SKirill A. Shutemov * Do not try to align to THP boundary if allocation at the address 62997d3d0f9SKirill A. Shutemov * hint succeeds. 63097d3d0f9SKirill A. Shutemov */ 63197d3d0f9SKirill A. Shutemov if (ret == addr) 63274d2fad1SToshi Kani return addr; 63397d3d0f9SKirill A. Shutemov 63497d3d0f9SKirill A. Shutemov ret += (off - ret) & (size - 1); 63597d3d0f9SKirill A. Shutemov return ret; 63674d2fad1SToshi Kani } 63774d2fad1SToshi Kani 63874d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 63974d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 64074d2fad1SToshi Kani { 64197d3d0f9SKirill A. Shutemov unsigned long ret; 64274d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 64374d2fad1SToshi Kani 64497d3d0f9SKirill A. Shutemov ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); 64597d3d0f9SKirill A. Shutemov if (ret) 64697d3d0f9SKirill A. Shutemov return ret; 6471854bc6eSWilliam Kucharski 64874d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 64974d2fad1SToshi Kani } 65074d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 65174d2fad1SToshi Kani 6522b740303SSouptick Joarder static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, 6532b740303SSouptick Joarder struct page *page, gfp_t gfp) 65471e3aac0SAndrea Arcangeli { 65582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 65671e3aac0SAndrea Arcangeli pgtable_t pgtable; 65782b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 6582b740303SSouptick Joarder vm_fault_t ret = 0; 65971e3aac0SAndrea Arcangeli 660309381feSSasha Levin VM_BUG_ON_PAGE(!PageCompound(page), page); 66100501b53SJohannes Weiner 6628f425e4eSMatthew Wilcox (Oracle) if (mem_cgroup_charge(page_folio(page), vma->vm_mm, gfp)) { 6636b251fc9SAndrea Arcangeli put_page(page); 6646b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 66585b9f46eSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK_CHARGE); 6666b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 6676b251fc9SAndrea Arcangeli } 6689d82c694SJohannes Weiner cgroup_throttle_swaprate(page, gfp); 66971e3aac0SAndrea Arcangeli 6704cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 67100501b53SJohannes Weiner if (unlikely(!pgtable)) { 6726b31d595SMichal Hocko ret = VM_FAULT_OOM; 6736b31d595SMichal Hocko goto release; 67400501b53SJohannes Weiner } 67500501b53SJohannes Weiner 676c79b57e4SHuang Ying clear_huge_page(page, vmf->address, HPAGE_PMD_NR); 67752f37629SMinchan Kim /* 67852f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 67952f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 68052f37629SMinchan Kim * write. 68152f37629SMinchan Kim */ 68271e3aac0SAndrea Arcangeli __SetPageUptodate(page); 68371e3aac0SAndrea Arcangeli 68482b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 68582b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 6866b31d595SMichal Hocko goto unlock_release; 68771e3aac0SAndrea Arcangeli } else { 68871e3aac0SAndrea Arcangeli pmd_t entry; 6896b251fc9SAndrea Arcangeli 6906b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 6916b31d595SMichal Hocko if (ret) 6926b31d595SMichal Hocko goto unlock_release; 6936b31d595SMichal Hocko 6946b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 6956b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 69682b0f8c3SJan Kara spin_unlock(vmf->ptl); 6976b251fc9SAndrea Arcangeli put_page(page); 698bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 6998fd5eda4SMiaohe Lin ret = handle_userfault(vmf, VM_UFFD_MISSING); 7008fd5eda4SMiaohe Lin VM_BUG_ON(ret & VM_FAULT_FALLBACK); 7018fd5eda4SMiaohe Lin return ret; 7026b251fc9SAndrea Arcangeli } 7036b251fc9SAndrea Arcangeli 7043122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 705f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 70640f2bbf7SDavid Hildenbrand page_add_new_anon_rmap(page, vma, haddr); 707b518154eSJoonsoo Kim lru_cache_add_inactive_or_unevictable(page, vma); 70882b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 70982b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 710fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 711bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 712c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 71382b0f8c3SJan Kara spin_unlock(vmf->ptl); 7146b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 7159d82c694SJohannes Weiner count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); 71671e3aac0SAndrea Arcangeli } 71771e3aac0SAndrea Arcangeli 718aa2e878eSDavid Rientjes return 0; 7196b31d595SMichal Hocko unlock_release: 7206b31d595SMichal Hocko spin_unlock(vmf->ptl); 7216b31d595SMichal Hocko release: 7226b31d595SMichal Hocko if (pgtable) 7236b31d595SMichal Hocko pte_free(vma->vm_mm, pgtable); 7246b31d595SMichal Hocko put_page(page); 7256b31d595SMichal Hocko return ret; 7266b31d595SMichal Hocko 72771e3aac0SAndrea Arcangeli } 72871e3aac0SAndrea Arcangeli 729444eb2a4SMel Gorman /* 73021440d7eSDavid Rientjes * always: directly stall for all thp allocations 73121440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 73221440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 73321440d7eSDavid Rientjes * fail if not immediately available 73421440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 73521440d7eSDavid Rientjes * available 73621440d7eSDavid Rientjes * never: never stall for any thp allocation 737444eb2a4SMel Gorman */ 738164cc4feSRik van Riel gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) 7390bbbc0b3SAndrea Arcangeli { 740164cc4feSRik van Riel const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); 74189c83fb5SMichal Hocko 742ac79f78dSDavid Rientjes /* Always do synchronous compaction */ 74321440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 744a8282608SAndrea Arcangeli return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 745ac79f78dSDavid Rientjes 746ac79f78dSDavid Rientjes /* Kick kcompactd and fail quickly */ 74721440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 74819deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 749ac79f78dSDavid Rientjes 750ac79f78dSDavid Rientjes /* Synchronous compaction if madvised, otherwise kick kcompactd */ 75121440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 75219deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 75319deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 754ac79f78dSDavid Rientjes __GFP_KSWAPD_RECLAIM); 755ac79f78dSDavid Rientjes 756ac79f78dSDavid Rientjes /* Only do synchronous compaction if madvised */ 75721440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 75819deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 75919deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); 760ac79f78dSDavid Rientjes 76119deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT; 762444eb2a4SMel Gorman } 763444eb2a4SMel Gorman 764c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 7652efeb8daSMiaohe Lin static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 76697ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 7675918d10aSKirill A. Shutemov struct page *zero_page) 768fc9fe822SKirill A. Shutemov { 769fc9fe822SKirill A. Shutemov pmd_t entry; 7707c414164SAndrew Morton if (!pmd_none(*pmd)) 7712efeb8daSMiaohe Lin return; 7725918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 773fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 77412c9d70bSMatthew Wilcox if (pgtable) 7756b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 776fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 777c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 778fc9fe822SKirill A. Shutemov } 779fc9fe822SKirill A. Shutemov 7802b740303SSouptick Joarder vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) 78171e3aac0SAndrea Arcangeli { 78282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 783077fcf11SAneesh Kumar K.V gfp_t gfp; 784cb196ee1SMatthew Wilcox (Oracle) struct folio *folio; 78582b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 78671e3aac0SAndrea Arcangeli 78743675e6fSYang Shi if (!transhuge_vma_suitable(vma, haddr)) 788c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 78971e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 79071e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 7914fa6893fSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 792d2081b2bSYang Shi 79382b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 794bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 79579da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 79680371957SKirill A. Shutemov pgtable_t pgtable; 7975918d10aSKirill A. Shutemov struct page *zero_page; 7982b740303SSouptick Joarder vm_fault_t ret; 7994cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 80080371957SKirill A. Shutemov if (unlikely(!pgtable)) 80180371957SKirill A. Shutemov return VM_FAULT_OOM; 8026fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 8035918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 804bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 80597ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 806c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 80797ae1749SKirill A. Shutemov } 80882b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 8096b251fc9SAndrea Arcangeli ret = 0; 81082b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 8116b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 8126b31d595SMichal Hocko if (ret) { 8136b31d595SMichal Hocko spin_unlock(vmf->ptl); 814bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 8156b31d595SMichal Hocko } else if (userfaultfd_missing(vma)) { 81682b0f8c3SJan Kara spin_unlock(vmf->ptl); 817bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 81882b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 8196b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 8206b251fc9SAndrea Arcangeli } else { 821bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 82282b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 823fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 82482b0f8c3SJan Kara spin_unlock(vmf->ptl); 8256b251fc9SAndrea Arcangeli } 826bfe8cc1dSGerald Schaefer } else { 82782b0f8c3SJan Kara spin_unlock(vmf->ptl); 828bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 829bfe8cc1dSGerald Schaefer } 8306b251fc9SAndrea Arcangeli return ret; 83180371957SKirill A. Shutemov } 832164cc4feSRik van Riel gfp = vma_thp_gfp_mask(vma); 833cb196ee1SMatthew Wilcox (Oracle) folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); 834cb196ee1SMatthew Wilcox (Oracle) if (unlikely(!folio)) { 83581ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 836c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 83781ab4201SAndi Kleen } 838cb196ee1SMatthew Wilcox (Oracle) return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); 83971e3aac0SAndrea Arcangeli } 84071e3aac0SAndrea Arcangeli 841ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 8423b6521f5SOliver O'Halloran pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, 8433b6521f5SOliver O'Halloran pgtable_t pgtable) 8445cad465dSMatthew Wilcox { 8455cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 8465cad465dSMatthew Wilcox pmd_t entry; 8475cad465dSMatthew Wilcox spinlock_t *ptl; 8485cad465dSMatthew Wilcox 8495cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 850c6f3c5eeSAneesh Kumar K.V if (!pmd_none(*pmd)) { 851c6f3c5eeSAneesh Kumar K.V if (write) { 852c6f3c5eeSAneesh Kumar K.V if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { 853c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); 854c6f3c5eeSAneesh Kumar K.V goto out_unlock; 855c6f3c5eeSAneesh Kumar K.V } 856c6f3c5eeSAneesh Kumar K.V entry = pmd_mkyoung(*pmd); 857c6f3c5eeSAneesh Kumar K.V entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 858c6f3c5eeSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) 859c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 860c6f3c5eeSAneesh Kumar K.V } 861c6f3c5eeSAneesh Kumar K.V 862c6f3c5eeSAneesh Kumar K.V goto out_unlock; 863c6f3c5eeSAneesh Kumar K.V } 864c6f3c5eeSAneesh Kumar K.V 865f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 866f25748e3SDan Williams if (pfn_t_devmap(pfn)) 867f25748e3SDan Williams entry = pmd_mkdevmap(entry); 8685cad465dSMatthew Wilcox if (write) { 869f55e1014SLinus Torvalds entry = pmd_mkyoung(pmd_mkdirty(entry)); 870f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(entry, vma); 8715cad465dSMatthew Wilcox } 8723b6521f5SOliver O'Halloran 8733b6521f5SOliver O'Halloran if (pgtable) { 8743b6521f5SOliver O'Halloran pgtable_trans_huge_deposit(mm, pmd, pgtable); 875c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 876c6f3c5eeSAneesh Kumar K.V pgtable = NULL; 8773b6521f5SOliver O'Halloran } 8783b6521f5SOliver O'Halloran 8795cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 8805cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 881c6f3c5eeSAneesh Kumar K.V 882c6f3c5eeSAneesh Kumar K.V out_unlock: 8835cad465dSMatthew Wilcox spin_unlock(ptl); 884c6f3c5eeSAneesh Kumar K.V if (pgtable) 885c6f3c5eeSAneesh Kumar K.V pte_free(mm, pgtable); 8865cad465dSMatthew Wilcox } 8875cad465dSMatthew Wilcox 8889a9731b1SThomas Hellstrom (VMware) /** 8899a9731b1SThomas Hellstrom (VMware) * vmf_insert_pfn_pmd_prot - insert a pmd size pfn 8909a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 8919a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 8929a9731b1SThomas Hellstrom (VMware) * @pgprot: page protection to use 8939a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 8949a9731b1SThomas Hellstrom (VMware) * 8959a9731b1SThomas Hellstrom (VMware) * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and 8969a9731b1SThomas Hellstrom (VMware) * also consult the vmf_insert_mixed_prot() documentation when 8979a9731b1SThomas Hellstrom (VMware) * @pgprot != @vmf->vma->vm_page_prot. 8989a9731b1SThomas Hellstrom (VMware) * 8999a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 9009a9731b1SThomas Hellstrom (VMware) */ 9019a9731b1SThomas Hellstrom (VMware) vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn, 9029a9731b1SThomas Hellstrom (VMware) pgprot_t pgprot, bool write) 9035cad465dSMatthew Wilcox { 904fce86ff5SDan Williams unsigned long addr = vmf->address & PMD_MASK; 905fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 9063b6521f5SOliver O'Halloran pgtable_t pgtable = NULL; 907fce86ff5SDan Williams 9085cad465dSMatthew Wilcox /* 9095cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 9105cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 9115cad465dSMatthew Wilcox * can't support a 'special' bit. 9125cad465dSMatthew Wilcox */ 913e1fb4a08SDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 914e1fb4a08SDave Jiang !pfn_t_devmap(pfn)); 9155cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 9165cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 9175cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 9185cad465dSMatthew Wilcox 9195cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 9205cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 921308a047cSBorislav Petkov 9223b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) { 9234cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 9243b6521f5SOliver O'Halloran if (!pgtable) 9253b6521f5SOliver O'Halloran return VM_FAULT_OOM; 9263b6521f5SOliver O'Halloran } 9273b6521f5SOliver O'Halloran 928308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 929308a047cSBorislav Petkov 930fce86ff5SDan Williams insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); 931ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 9325cad465dSMatthew Wilcox } 9339a9731b1SThomas Hellstrom (VMware) EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot); 9345cad465dSMatthew Wilcox 935a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 936f55e1014SLinus Torvalds static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 937a00cc7d9SMatthew Wilcox { 938f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 939a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 940a00cc7d9SMatthew Wilcox return pud; 941a00cc7d9SMatthew Wilcox } 942a00cc7d9SMatthew Wilcox 943a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 944a00cc7d9SMatthew Wilcox pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) 945a00cc7d9SMatthew Wilcox { 946a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 947a00cc7d9SMatthew Wilcox pud_t entry; 948a00cc7d9SMatthew Wilcox spinlock_t *ptl; 949a00cc7d9SMatthew Wilcox 950a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 951c6f3c5eeSAneesh Kumar K.V if (!pud_none(*pud)) { 952c6f3c5eeSAneesh Kumar K.V if (write) { 953c6f3c5eeSAneesh Kumar K.V if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { 954c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pud(*pud)); 955c6f3c5eeSAneesh Kumar K.V goto out_unlock; 956c6f3c5eeSAneesh Kumar K.V } 957c6f3c5eeSAneesh Kumar K.V entry = pud_mkyoung(*pud); 958c6f3c5eeSAneesh Kumar K.V entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); 959c6f3c5eeSAneesh Kumar K.V if (pudp_set_access_flags(vma, addr, pud, entry, 1)) 960c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pud(vma, addr, pud); 961c6f3c5eeSAneesh Kumar K.V } 962c6f3c5eeSAneesh Kumar K.V goto out_unlock; 963c6f3c5eeSAneesh Kumar K.V } 964c6f3c5eeSAneesh Kumar K.V 965a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 966a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 967a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 968a00cc7d9SMatthew Wilcox if (write) { 969f55e1014SLinus Torvalds entry = pud_mkyoung(pud_mkdirty(entry)); 970f55e1014SLinus Torvalds entry = maybe_pud_mkwrite(entry, vma); 971a00cc7d9SMatthew Wilcox } 972a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 973a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 974c6f3c5eeSAneesh Kumar K.V 975c6f3c5eeSAneesh Kumar K.V out_unlock: 976a00cc7d9SMatthew Wilcox spin_unlock(ptl); 977a00cc7d9SMatthew Wilcox } 978a00cc7d9SMatthew Wilcox 9799a9731b1SThomas Hellstrom (VMware) /** 9809a9731b1SThomas Hellstrom (VMware) * vmf_insert_pfn_pud_prot - insert a pud size pfn 9819a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 9829a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 9839a9731b1SThomas Hellstrom (VMware) * @pgprot: page protection to use 9849a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 9859a9731b1SThomas Hellstrom (VMware) * 9869a9731b1SThomas Hellstrom (VMware) * Insert a pud size pfn. See vmf_insert_pfn() for additional info and 9879a9731b1SThomas Hellstrom (VMware) * also consult the vmf_insert_mixed_prot() documentation when 9889a9731b1SThomas Hellstrom (VMware) * @pgprot != @vmf->vma->vm_page_prot. 9899a9731b1SThomas Hellstrom (VMware) * 9909a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 9919a9731b1SThomas Hellstrom (VMware) */ 9929a9731b1SThomas Hellstrom (VMware) vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, 9939a9731b1SThomas Hellstrom (VMware) pgprot_t pgprot, bool write) 994a00cc7d9SMatthew Wilcox { 995fce86ff5SDan Williams unsigned long addr = vmf->address & PUD_MASK; 996fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 997fce86ff5SDan Williams 998a00cc7d9SMatthew Wilcox /* 999a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 1000a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 1001a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 1002a00cc7d9SMatthew Wilcox */ 100362ec0d8cSDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 100462ec0d8cSDave Jiang !pfn_t_devmap(pfn)); 1005a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 1006a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 1007a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 1008a00cc7d9SMatthew Wilcox 1009a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 1010a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 1011a00cc7d9SMatthew Wilcox 1012a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 1013a00cc7d9SMatthew Wilcox 1014fce86ff5SDan Williams insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); 1015a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 1016a00cc7d9SMatthew Wilcox } 10179a9731b1SThomas Hellstrom (VMware) EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot); 1018a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1019a00cc7d9SMatthew Wilcox 10203565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 1021a69e4717SMiaohe Lin pmd_t *pmd, bool write) 10223565fce3SDan Williams { 10233565fce3SDan Williams pmd_t _pmd; 10243565fce3SDan Williams 1025a8f97366SKirill A. Shutemov _pmd = pmd_mkyoung(*pmd); 1026a69e4717SMiaohe Lin if (write) 1027a8f97366SKirill A. Shutemov _pmd = pmd_mkdirty(_pmd); 10283565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 1029a69e4717SMiaohe Lin pmd, _pmd, write)) 10303565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 10313565fce3SDan Williams } 10323565fce3SDan Williams 10333565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 1034df06b37fSKeith Busch pmd_t *pmd, int flags, struct dev_pagemap **pgmap) 10353565fce3SDan Williams { 10363565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 10373565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 10383565fce3SDan Williams struct page *page; 10393565fce3SDan Williams 10403565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 10413565fce3SDan Williams 10428310d48bSKeno Fischer /* 10438310d48bSKeno Fischer * When we COW a devmap PMD entry, we split it into PTEs, so we should 10448310d48bSKeno Fischer * not be in this function with `flags & FOLL_COW` set. 10458310d48bSKeno Fischer */ 10468310d48bSKeno Fischer WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); 10478310d48bSKeno Fischer 10483faa52c0SJohn Hubbard /* FOLL_GET and FOLL_PIN are mutually exclusive. */ 10493faa52c0SJohn Hubbard if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == 10503faa52c0SJohn Hubbard (FOLL_PIN | FOLL_GET))) 10513faa52c0SJohn Hubbard return NULL; 10523faa52c0SJohn Hubbard 1053f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pmd_write(*pmd)) 10543565fce3SDan Williams return NULL; 10553565fce3SDan Williams 10563565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 10573565fce3SDan Williams /* pass */; 10583565fce3SDan Williams else 10593565fce3SDan Williams return NULL; 10603565fce3SDan Williams 10613565fce3SDan Williams if (flags & FOLL_TOUCH) 1062a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 10633565fce3SDan Williams 10643565fce3SDan Williams /* 10653565fce3SDan Williams * device mapped pages can only be returned if the 10663565fce3SDan Williams * caller will manage the page reference count. 10673565fce3SDan Williams */ 10683faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 10693565fce3SDan Williams return ERR_PTR(-EEXIST); 10703565fce3SDan Williams 10713565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 1072df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1073df06b37fSKeith Busch if (!*pgmap) 10743565fce3SDan Williams return ERR_PTR(-EFAULT); 10753565fce3SDan Williams page = pfn_to_page(pfn); 10763faa52c0SJohn Hubbard if (!try_grab_page(page, flags)) 10773faa52c0SJohn Hubbard page = ERR_PTR(-ENOMEM); 10783565fce3SDan Williams 10793565fce3SDan Williams return page; 10803565fce3SDan Williams } 10813565fce3SDan Williams 108271e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 108371e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 10848f34f1eaSPeter Xu struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 108571e3aac0SAndrea Arcangeli { 1086c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 108771e3aac0SAndrea Arcangeli struct page *src_page; 108871e3aac0SAndrea Arcangeli pmd_t pmd; 108912c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 1090628d47ceSKirill A. Shutemov int ret = -ENOMEM; 109171e3aac0SAndrea Arcangeli 1092628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 10938f34f1eaSPeter Xu if (!vma_is_anonymous(dst_vma)) 1094628d47ceSKirill A. Shutemov return 0; 1095628d47ceSKirill A. Shutemov 10964cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(dst_mm); 109771e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 109871e3aac0SAndrea Arcangeli goto out; 109971e3aac0SAndrea Arcangeli 1100c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 1101c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 1102c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 110371e3aac0SAndrea Arcangeli 110471e3aac0SAndrea Arcangeli ret = -EAGAIN; 110571e3aac0SAndrea Arcangeli pmd = *src_pmd; 110684c3fc4eSZi Yan 110784c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 110884c3fc4eSZi Yan if (unlikely(is_swap_pmd(pmd))) { 110984c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(pmd); 111084c3fc4eSZi Yan 111184c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(pmd)); 11126c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) { 11134dd845b5SAlistair Popple entry = make_readable_migration_entry( 11144dd845b5SAlistair Popple swp_offset(entry)); 111584c3fc4eSZi Yan pmd = swp_entry_to_pmd(entry); 1116ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*src_pmd)) 1117ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 11188f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*src_pmd)) 11198f34f1eaSPeter Xu pmd = pmd_swp_mkuffd_wp(pmd); 112084c3fc4eSZi Yan set_pmd_at(src_mm, addr, src_pmd, pmd); 112184c3fc4eSZi Yan } 1122dd8a67f9SZi Yan add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1123af5b0f6aSKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 1124dd8a67f9SZi Yan pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 11258f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11268f34f1eaSPeter Xu pmd = pmd_swp_clear_uffd_wp(pmd); 112784c3fc4eSZi Yan set_pmd_at(dst_mm, addr, dst_pmd, pmd); 112884c3fc4eSZi Yan ret = 0; 112984c3fc4eSZi Yan goto out_unlock; 113084c3fc4eSZi Yan } 113184c3fc4eSZi Yan #endif 113284c3fc4eSZi Yan 1133628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 113471e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 113571e3aac0SAndrea Arcangeli goto out_unlock; 113671e3aac0SAndrea Arcangeli } 1137fc9fe822SKirill A. Shutemov /* 1138c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 1139fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 1140fc9fe822SKirill A. Shutemov * a page table. 1141fc9fe822SKirill A. Shutemov */ 1142fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 114397ae1749SKirill A. Shutemov /* 114497ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 114597ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 114697ae1749SKirill A. Shutemov * reference. 114797ae1749SKirill A. Shutemov */ 11485fc7a5f6SPeter Xu mm_get_huge_zero_page(dst_mm); 11495fc7a5f6SPeter Xu goto out_zero_page; 1150fc9fe822SKirill A. Shutemov } 1151de466bd6SMel Gorman 115271e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 1153309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 1154d042035eSPeter Xu 1155fb3d824dSDavid Hildenbrand get_page(src_page); 1156fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { 1157fb3d824dSDavid Hildenbrand /* Page maybe pinned: split and retry the fault on PTEs. */ 1158fb3d824dSDavid Hildenbrand put_page(src_page); 1159d042035eSPeter Xu pte_free(dst_mm, pgtable); 1160d042035eSPeter Xu spin_unlock(src_ptl); 1161d042035eSPeter Xu spin_unlock(dst_ptl); 11628f34f1eaSPeter Xu __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); 1163d042035eSPeter Xu return -EAGAIN; 1164d042035eSPeter Xu } 116571e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 11665fc7a5f6SPeter Xu out_zero_page: 1167c4812909SKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 11685c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 116971e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 11708f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 11718f34f1eaSPeter Xu pmd = pmd_clear_uffd_wp(pmd); 117271e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 117371e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 117471e3aac0SAndrea Arcangeli 117571e3aac0SAndrea Arcangeli ret = 0; 117671e3aac0SAndrea Arcangeli out_unlock: 1177c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 1178c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 117971e3aac0SAndrea Arcangeli out: 118071e3aac0SAndrea Arcangeli return ret; 118171e3aac0SAndrea Arcangeli } 118271e3aac0SAndrea Arcangeli 1183a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1184a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 11855fe653e9SMiaohe Lin pud_t *pud, bool write) 1186a00cc7d9SMatthew Wilcox { 1187a00cc7d9SMatthew Wilcox pud_t _pud; 1188a00cc7d9SMatthew Wilcox 1189a8f97366SKirill A. Shutemov _pud = pud_mkyoung(*pud); 11905fe653e9SMiaohe Lin if (write) 1191a8f97366SKirill A. Shutemov _pud = pud_mkdirty(_pud); 1192a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 11935fe653e9SMiaohe Lin pud, _pud, write)) 1194a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1195a00cc7d9SMatthew Wilcox } 1196a00cc7d9SMatthew Wilcox 1197a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 1198df06b37fSKeith Busch pud_t *pud, int flags, struct dev_pagemap **pgmap) 1199a00cc7d9SMatthew Wilcox { 1200a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 1201a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1202a00cc7d9SMatthew Wilcox struct page *page; 1203a00cc7d9SMatthew Wilcox 1204a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 1205a00cc7d9SMatthew Wilcox 1206f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pud_write(*pud)) 1207a00cc7d9SMatthew Wilcox return NULL; 1208a00cc7d9SMatthew Wilcox 12093faa52c0SJohn Hubbard /* FOLL_GET and FOLL_PIN are mutually exclusive. */ 12103faa52c0SJohn Hubbard if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == 12113faa52c0SJohn Hubbard (FOLL_PIN | FOLL_GET))) 12123faa52c0SJohn Hubbard return NULL; 12133faa52c0SJohn Hubbard 1214a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 1215a00cc7d9SMatthew Wilcox /* pass */; 1216a00cc7d9SMatthew Wilcox else 1217a00cc7d9SMatthew Wilcox return NULL; 1218a00cc7d9SMatthew Wilcox 1219a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 12205fe653e9SMiaohe Lin touch_pud(vma, addr, pud, flags & FOLL_WRITE); 1221a00cc7d9SMatthew Wilcox 1222a00cc7d9SMatthew Wilcox /* 1223a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 1224a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 12253faa52c0SJohn Hubbard * 12263faa52c0SJohn Hubbard * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: 1227a00cc7d9SMatthew Wilcox */ 12283faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 1229a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 1230a00cc7d9SMatthew Wilcox 1231a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 1232df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1233df06b37fSKeith Busch if (!*pgmap) 1234a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 1235a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 12363faa52c0SJohn Hubbard if (!try_grab_page(page, flags)) 12373faa52c0SJohn Hubbard page = ERR_PTR(-ENOMEM); 1238a00cc7d9SMatthew Wilcox 1239a00cc7d9SMatthew Wilcox return page; 1240a00cc7d9SMatthew Wilcox } 1241a00cc7d9SMatthew Wilcox 1242a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1243a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1244a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1245a00cc7d9SMatthew Wilcox { 1246a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1247a00cc7d9SMatthew Wilcox pud_t pud; 1248a00cc7d9SMatthew Wilcox int ret; 1249a00cc7d9SMatthew Wilcox 1250a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1251a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1252a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1253a00cc7d9SMatthew Wilcox 1254a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1255a00cc7d9SMatthew Wilcox pud = *src_pud; 1256a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1257a00cc7d9SMatthew Wilcox goto out_unlock; 1258a00cc7d9SMatthew Wilcox 1259a00cc7d9SMatthew Wilcox /* 1260a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1261a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1262a00cc7d9SMatthew Wilcox * a page table. 1263a00cc7d9SMatthew Wilcox */ 1264a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1265a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1266a00cc7d9SMatthew Wilcox } 1267a00cc7d9SMatthew Wilcox 1268fb3d824dSDavid Hildenbrand /* 1269fb3d824dSDavid Hildenbrand * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() 1270fb3d824dSDavid Hildenbrand * and split if duplicating fails. 1271fb3d824dSDavid Hildenbrand */ 1272a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1273a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1274a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1275a00cc7d9SMatthew Wilcox 1276a00cc7d9SMatthew Wilcox ret = 0; 1277a00cc7d9SMatthew Wilcox out_unlock: 1278a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1279a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1280a00cc7d9SMatthew Wilcox return ret; 1281a00cc7d9SMatthew Wilcox } 1282a00cc7d9SMatthew Wilcox 1283a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1284a00cc7d9SMatthew Wilcox { 1285a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1286a00cc7d9SMatthew Wilcox 1287a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1288a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1289a00cc7d9SMatthew Wilcox goto unlock; 1290a00cc7d9SMatthew Wilcox 12915fe653e9SMiaohe Lin touch_pud(vmf->vma, vmf->address, vmf->pud, write); 1292a00cc7d9SMatthew Wilcox unlock: 1293a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1294a00cc7d9SMatthew Wilcox } 1295a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1296a00cc7d9SMatthew Wilcox 12975db4f15cSYang Shi void huge_pmd_set_accessed(struct vm_fault *vmf) 1298a1dd450bSWill Deacon { 129920f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1300a1dd450bSWill Deacon 130182b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 1302a69e4717SMiaohe Lin if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) 1303a1dd450bSWill Deacon goto unlock; 1304a1dd450bSWill Deacon 1305a69e4717SMiaohe Lin touch_pmd(vmf->vma, vmf->address, vmf->pmd, write); 1306a1dd450bSWill Deacon 1307a1dd450bSWill Deacon unlock: 130882b0f8c3SJan Kara spin_unlock(vmf->ptl); 1309a1dd450bSWill Deacon } 1310a1dd450bSWill Deacon 13115db4f15cSYang Shi vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) 131271e3aac0SAndrea Arcangeli { 1313c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 131482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 13153917c802SKirill A. Shutemov struct page *page; 131682b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 13175db4f15cSYang Shi pmd_t orig_pmd = vmf->orig_pmd; 131871e3aac0SAndrea Arcangeli 131982b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 132081d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 13213917c802SKirill A. Shutemov 1322c89357e2SDavid Hildenbrand VM_BUG_ON(unshare && (vmf->flags & FAULT_FLAG_WRITE)); 1323c89357e2SDavid Hildenbrand VM_BUG_ON(!unshare && !(vmf->flags & FAULT_FLAG_WRITE)); 1324c89357e2SDavid Hildenbrand 132593b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 13263917c802SKirill A. Shutemov goto fallback; 13273917c802SKirill A. Shutemov 132882b0f8c3SJan Kara spin_lock(vmf->ptl); 13293917c802SKirill A. Shutemov 13303917c802SKirill A. Shutemov if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13313917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13323917c802SKirill A. Shutemov return 0; 13333917c802SKirill A. Shutemov } 133471e3aac0SAndrea Arcangeli 133571e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 1336f6004e73SMiaohe Lin VM_BUG_ON_PAGE(!PageHead(page), page); 13373917c802SKirill A. Shutemov 13386c287605SDavid Hildenbrand /* Early check when only holding the PT lock. */ 13396c287605SDavid Hildenbrand if (PageAnonExclusive(page)) 13406c287605SDavid Hildenbrand goto reuse; 13416c287605SDavid Hildenbrand 1342ba3c4ce6SHuang Ying if (!trylock_page(page)) { 1343ba3c4ce6SHuang Ying get_page(page); 1344ba3c4ce6SHuang Ying spin_unlock(vmf->ptl); 1345ba3c4ce6SHuang Ying lock_page(page); 1346ba3c4ce6SHuang Ying spin_lock(vmf->ptl); 1347ba3c4ce6SHuang Ying if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 13483917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 1349ba3c4ce6SHuang Ying unlock_page(page); 1350ba3c4ce6SHuang Ying put_page(page); 13513917c802SKirill A. Shutemov return 0; 1352ba3c4ce6SHuang Ying } 1353ba3c4ce6SHuang Ying put_page(page); 1354ba3c4ce6SHuang Ying } 13553917c802SKirill A. Shutemov 13566c287605SDavid Hildenbrand /* Recheck after temporarily dropping the PT lock. */ 13576c287605SDavid Hildenbrand if (PageAnonExclusive(page)) { 13586c287605SDavid Hildenbrand unlock_page(page); 13596c287605SDavid Hildenbrand goto reuse; 13606c287605SDavid Hildenbrand } 13616c287605SDavid Hildenbrand 13623917c802SKirill A. Shutemov /* 1363c89357e2SDavid Hildenbrand * See do_wp_page(): we can only reuse the page exclusively if there are 13643bff7e3fSDavid Hildenbrand * no additional references. Note that we always drain the LRU 13653bff7e3fSDavid Hildenbrand * pagevecs immediately after adding a THP. 13663917c802SKirill A. Shutemov */ 13673bff7e3fSDavid Hildenbrand if (page_count(page) > 1 + PageSwapCache(page) * thp_nr_pages(page)) 13683bff7e3fSDavid Hildenbrand goto unlock_fallback; 13693bff7e3fSDavid Hildenbrand if (PageSwapCache(page)) 13703bff7e3fSDavid Hildenbrand try_to_free_swap(page); 13713bff7e3fSDavid Hildenbrand if (page_count(page) == 1) { 137271e3aac0SAndrea Arcangeli pmd_t entry; 13736c54dc6cSDavid Hildenbrand 13746c54dc6cSDavid Hildenbrand page_move_anon_rmap(page, vma); 13756c287605SDavid Hildenbrand unlock_page(page); 13766c287605SDavid Hildenbrand reuse: 1377c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 1378c89357e2SDavid Hildenbrand spin_unlock(vmf->ptl); 1379c89357e2SDavid Hildenbrand return 0; 1380c89357e2SDavid Hildenbrand } 138171e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 1382f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 138382b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 138482b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 13853917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 13863917c802SKirill A. Shutemov return VM_FAULT_WRITE; 138771e3aac0SAndrea Arcangeli } 13883917c802SKirill A. Shutemov 13893bff7e3fSDavid Hildenbrand unlock_fallback: 1390ba3c4ce6SHuang Ying unlock_page(page); 139182b0f8c3SJan Kara spin_unlock(vmf->ptl); 13923917c802SKirill A. Shutemov fallback: 13933917c802SKirill A. Shutemov __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); 13943917c802SKirill A. Shutemov return VM_FAULT_FALLBACK; 139571e3aac0SAndrea Arcangeli } 139671e3aac0SAndrea Arcangeli 13978310d48bSKeno Fischer /* 1398a308c71bSPeter Xu * FOLL_FORCE can write to even unwritable pmd's, but only 1399a308c71bSPeter Xu * after we've gone through a COW cycle and they are dirty. 14008310d48bSKeno Fischer */ 14018310d48bSKeno Fischer static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) 14028310d48bSKeno Fischer { 1403a308c71bSPeter Xu return pmd_write(pmd) || 1404a308c71bSPeter Xu ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); 14058310d48bSKeno Fischer } 14068310d48bSKeno Fischer 1407b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 140871e3aac0SAndrea Arcangeli unsigned long addr, 140971e3aac0SAndrea Arcangeli pmd_t *pmd, 141071e3aac0SAndrea Arcangeli unsigned int flags) 141171e3aac0SAndrea Arcangeli { 1412b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 141371e3aac0SAndrea Arcangeli struct page *page = NULL; 141471e3aac0SAndrea Arcangeli 1415c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 141671e3aac0SAndrea Arcangeli 14178310d48bSKeno Fischer if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) 141871e3aac0SAndrea Arcangeli goto out; 141971e3aac0SAndrea Arcangeli 142085facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 142185facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 142285facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 142385facf25SKirill A. Shutemov 14242b4847e7SMel Gorman /* Full NUMA hinting faults to serialise migration in fault paths */ 14258a0516edSMel Gorman if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) 14262b4847e7SMel Gorman goto out; 14272b4847e7SMel Gorman 142871e3aac0SAndrea Arcangeli page = pmd_page(*pmd); 1429ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 14303faa52c0SJohn Hubbard 1431a7f22660SDavid Hildenbrand if (!pmd_write(*pmd) && gup_must_unshare(flags, page)) 1432a7f22660SDavid Hildenbrand return ERR_PTR(-EMLINK); 1433a7f22660SDavid Hildenbrand 1434b6a2619cSDavid Hildenbrand VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && 1435b6a2619cSDavid Hildenbrand !PageAnonExclusive(page), page); 1436b6a2619cSDavid Hildenbrand 14373faa52c0SJohn Hubbard if (!try_grab_page(page, flags)) 14383faa52c0SJohn Hubbard return ERR_PTR(-ENOMEM); 14393faa52c0SJohn Hubbard 14403565fce3SDan Williams if (flags & FOLL_TOUCH) 1441a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 14423faa52c0SJohn Hubbard 144371e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1444ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 144571e3aac0SAndrea Arcangeli 144671e3aac0SAndrea Arcangeli out: 144771e3aac0SAndrea Arcangeli return page; 144871e3aac0SAndrea Arcangeli } 144971e3aac0SAndrea Arcangeli 1450d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 14515db4f15cSYang Shi vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) 1452d10e63f2SMel Gorman { 145382b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1454c5b5a3ddSYang Shi pmd_t oldpmd = vmf->orig_pmd; 1455c5b5a3ddSYang Shi pmd_t pmd; 1456b32967ffSMel Gorman struct page *page; 145782b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 1458c5b5a3ddSYang Shi int page_nid = NUMA_NO_NODE; 145990572890SPeter Zijlstra int target_nid, last_cpupid = -1; 14608191acbdSMel Gorman bool migrated = false; 1461c5b5a3ddSYang Shi bool was_writable = pmd_savedwrite(oldpmd); 14626688cc05SPeter Zijlstra int flags = 0; 1463d10e63f2SMel Gorman 146482b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1465c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 146682b0f8c3SJan Kara spin_unlock(vmf->ptl); 1467de466bd6SMel Gorman goto out; 1468de466bd6SMel Gorman } 1469de466bd6SMel Gorman 1470c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 1471c5b5a3ddSYang Shi page = vm_normal_page_pmd(vma, haddr, pmd); 1472c5b5a3ddSYang Shi if (!page) 1473c5b5a3ddSYang Shi goto out_map; 1474c5b5a3ddSYang Shi 1475c5b5a3ddSYang Shi /* See similar comment in do_numa_page for explanation */ 1476c5b5a3ddSYang Shi if (!was_writable) 1477c5b5a3ddSYang Shi flags |= TNF_NO_GROUP; 1478c5b5a3ddSYang Shi 1479c5b5a3ddSYang Shi page_nid = page_to_nid(page); 1480c5b5a3ddSYang Shi last_cpupid = page_cpupid_last(page); 1481c5b5a3ddSYang Shi target_nid = numa_migrate_prep(page, vma, haddr, page_nid, 1482c5b5a3ddSYang Shi &flags); 1483c5b5a3ddSYang Shi 1484c5b5a3ddSYang Shi if (target_nid == NUMA_NO_NODE) { 1485c5b5a3ddSYang Shi put_page(page); 1486c5b5a3ddSYang Shi goto out_map; 1487c5b5a3ddSYang Shi } 1488c5b5a3ddSYang Shi 148982b0f8c3SJan Kara spin_unlock(vmf->ptl); 14908b1b436dSPeter Zijlstra 1491c5b5a3ddSYang Shi migrated = migrate_misplaced_page(page, vma, target_nid); 14926688cc05SPeter Zijlstra if (migrated) { 14936688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 14948191acbdSMel Gorman page_nid = target_nid; 1495c5b5a3ddSYang Shi } else { 1496074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1497c5b5a3ddSYang Shi vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1498c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 149982b0f8c3SJan Kara spin_unlock(vmf->ptl); 1500c5b5a3ddSYang Shi goto out; 1501c5b5a3ddSYang Shi } 1502c5b5a3ddSYang Shi goto out_map; 1503c5b5a3ddSYang Shi } 1504b8916634SMel Gorman 1505b8916634SMel Gorman out: 150698fa15f3SAnshuman Khandual if (page_nid != NUMA_NO_NODE) 150782b0f8c3SJan Kara task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, 15089a8b300fSAneesh Kumar K.V flags); 15098191acbdSMel Gorman 1510d10e63f2SMel Gorman return 0; 1511c5b5a3ddSYang Shi 1512c5b5a3ddSYang Shi out_map: 1513c5b5a3ddSYang Shi /* Restore the PMD */ 1514c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 1515c5b5a3ddSYang Shi pmd = pmd_mkyoung(pmd); 1516c5b5a3ddSYang Shi if (was_writable) 1517c5b5a3ddSYang Shi pmd = pmd_mkwrite(pmd); 1518c5b5a3ddSYang Shi set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 1519c5b5a3ddSYang Shi update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1520c5b5a3ddSYang Shi spin_unlock(vmf->ptl); 1521c5b5a3ddSYang Shi goto out; 1522d10e63f2SMel Gorman } 1523d10e63f2SMel Gorman 1524319904adSHuang Ying /* 1525319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1526319904adSHuang Ying * Otherwise, return false. 1527319904adSHuang Ying */ 1528319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1529b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1530b8d3c4c3SMinchan Kim { 1531b8d3c4c3SMinchan Kim spinlock_t *ptl; 1532b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1533b8d3c4c3SMinchan Kim struct page *page; 1534b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1535319904adSHuang Ying bool ret = false; 1536b8d3c4c3SMinchan Kim 1537ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 153807e32661SAneesh Kumar K.V 1539b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1540b6ec57f4SKirill A. Shutemov if (!ptl) 154125eedabeSLinus Torvalds goto out_unlocked; 1542b8d3c4c3SMinchan Kim 1543b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1544319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1545b8d3c4c3SMinchan Kim goto out; 1546b8d3c4c3SMinchan Kim 154784c3fc4eSZi Yan if (unlikely(!pmd_present(orig_pmd))) { 154884c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 154984c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 155084c3fc4eSZi Yan goto out; 155184c3fc4eSZi Yan } 155284c3fc4eSZi Yan 1553b8d3c4c3SMinchan Kim page = pmd_page(orig_pmd); 1554b8d3c4c3SMinchan Kim /* 1555b8d3c4c3SMinchan Kim * If other processes are mapping this page, we couldn't discard 1556b8d3c4c3SMinchan Kim * the page unless they all do MADV_FREE so let's skip the page. 1557b8d3c4c3SMinchan Kim */ 1558babbbdd0SMiaohe Lin if (total_mapcount(page) != 1) 1559b8d3c4c3SMinchan Kim goto out; 1560b8d3c4c3SMinchan Kim 1561b8d3c4c3SMinchan Kim if (!trylock_page(page)) 1562b8d3c4c3SMinchan Kim goto out; 1563b8d3c4c3SMinchan Kim 1564b8d3c4c3SMinchan Kim /* 1565b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1566b8d3c4c3SMinchan Kim * will deactivate only them. 1567b8d3c4c3SMinchan Kim */ 1568b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1569b8d3c4c3SMinchan Kim get_page(page); 1570b8d3c4c3SMinchan Kim spin_unlock(ptl); 15719818b8cdSHuang Ying split_huge_page(page); 1572b8d3c4c3SMinchan Kim unlock_page(page); 1573bbf29ffcSKirill A. Shutemov put_page(page); 1574b8d3c4c3SMinchan Kim goto out_unlocked; 1575b8d3c4c3SMinchan Kim } 1576b8d3c4c3SMinchan Kim 1577b8d3c4c3SMinchan Kim if (PageDirty(page)) 1578b8d3c4c3SMinchan Kim ClearPageDirty(page); 1579b8d3c4c3SMinchan Kim unlock_page(page); 1580b8d3c4c3SMinchan Kim 1581b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 158258ceeb6bSKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1583b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1584b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1585b8d3c4c3SMinchan Kim 1586b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1587b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1588b8d3c4c3SMinchan Kim } 1589802a3a92SShaohua Li 1590802a3a92SShaohua Li mark_page_lazyfree(page); 1591319904adSHuang Ying ret = true; 1592b8d3c4c3SMinchan Kim out: 1593b8d3c4c3SMinchan Kim spin_unlock(ptl); 1594b8d3c4c3SMinchan Kim out_unlocked: 1595b8d3c4c3SMinchan Kim return ret; 1596b8d3c4c3SMinchan Kim } 1597b8d3c4c3SMinchan Kim 1598953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1599953c66c2SAneesh Kumar K.V { 1600953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1601953c66c2SAneesh Kumar K.V 1602953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1603953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1604c4812909SKirill A. Shutemov mm_dec_nr_ptes(mm); 1605953c66c2SAneesh Kumar K.V } 1606953c66c2SAneesh Kumar K.V 160771e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1608f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 160971e3aac0SAndrea Arcangeli { 1610f5c8ad47SDavid Miller pmd_t orig_pmd; 1611da146769SKirill A. Shutemov spinlock_t *ptl; 1612da146769SKirill A. Shutemov 1613ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 161407e32661SAneesh Kumar K.V 1615b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1616b6ec57f4SKirill A. Shutemov if (!ptl) 1617da146769SKirill A. Shutemov return 0; 1618a6bf2bb0SAneesh Kumar K.V /* 1619a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 16208809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1621a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1622a6bf2bb0SAneesh Kumar K.V * operations. 1623a6bf2bb0SAneesh Kumar K.V */ 162493a98695SAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, 1625fcbe08d6SMartin Schwidefsky tlb->fullmm); 1626f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 16272484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 16283b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) 16293b6521f5SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 16304897c765SMatthew Wilcox spin_unlock(ptl); 1631da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1632c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1633bf929152SKirill A. Shutemov spin_unlock(ptl); 1634479f0abbSKirill A. Shutemov } else { 1635616b8371SZi Yan struct page *page = NULL; 1636616b8371SZi Yan int flush_needed = 1; 1637616b8371SZi Yan 1638616b8371SZi Yan if (pmd_present(orig_pmd)) { 1639616b8371SZi Yan page = pmd_page(orig_pmd); 1640cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 1641309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1642309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1643616b8371SZi Yan } else if (thp_migration_supported()) { 1644616b8371SZi Yan swp_entry_t entry; 1645616b8371SZi Yan 1646616b8371SZi Yan VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); 1647616b8371SZi Yan entry = pmd_to_swp_entry(orig_pmd); 1648af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1649616b8371SZi Yan flush_needed = 0; 1650616b8371SZi Yan } else 1651616b8371SZi Yan WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); 1652616b8371SZi Yan 1653b5072380SKirill A. Shutemov if (PageAnon(page)) { 1654c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1655b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1656b5072380SKirill A. Shutemov } else { 1657953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1658953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1659fadae295SYang Shi add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); 1660b5072380SKirill A. Shutemov } 1661616b8371SZi Yan 1662bf929152SKirill A. Shutemov spin_unlock(ptl); 1663616b8371SZi Yan if (flush_needed) 1664e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1665479f0abbSKirill A. Shutemov } 1666da146769SKirill A. Shutemov return 1; 166771e3aac0SAndrea Arcangeli } 166871e3aac0SAndrea Arcangeli 16691dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 16701dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 16711dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 16721dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 16731dd38b6cSAneesh Kumar K.V { 16741dd38b6cSAneesh Kumar K.V /* 16751dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 16761dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 16771dd38b6cSAneesh Kumar K.V * 16781dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 16791dd38b6cSAneesh Kumar K.V */ 16801dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 16811dd38b6cSAneesh Kumar K.V } 16821dd38b6cSAneesh Kumar K.V #endif 16831dd38b6cSAneesh Kumar K.V 1684ab6e3d09SNaoya Horiguchi static pmd_t move_soft_dirty_pmd(pmd_t pmd) 1685ab6e3d09SNaoya Horiguchi { 1686ab6e3d09SNaoya Horiguchi #ifdef CONFIG_MEM_SOFT_DIRTY 1687ab6e3d09SNaoya Horiguchi if (unlikely(is_pmd_migration_entry(pmd))) 1688ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 1689ab6e3d09SNaoya Horiguchi else if (pmd_present(pmd)) 1690ab6e3d09SNaoya Horiguchi pmd = pmd_mksoft_dirty(pmd); 1691ab6e3d09SNaoya Horiguchi #endif 1692ab6e3d09SNaoya Horiguchi return pmd; 1693ab6e3d09SNaoya Horiguchi } 1694ab6e3d09SNaoya Horiguchi 1695bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 1696b8aa9d9dSWei Yang unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) 169737a1c49aSAndrea Arcangeli { 1698bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 169937a1c49aSAndrea Arcangeli pmd_t pmd; 170037a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 17015d190420SAaron Lu bool force_flush = false; 170237a1c49aSAndrea Arcangeli 170337a1c49aSAndrea Arcangeli /* 170437a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 170537a1c49aSAndrea Arcangeli * should have release it. 170637a1c49aSAndrea Arcangeli */ 170737a1c49aSAndrea Arcangeli if (WARN_ON(!pmd_none(*new_pmd))) { 170837a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 17094b471e88SKirill A. Shutemov return false; 171037a1c49aSAndrea Arcangeli } 171137a1c49aSAndrea Arcangeli 1712bf929152SKirill A. Shutemov /* 1713bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1714c1e8d7c6SMichel Lespinasse * ptlocks because exclusive mmap_lock prevents deadlock. 1715bf929152SKirill A. Shutemov */ 1716b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1717b6ec57f4SKirill A. Shutemov if (old_ptl) { 1718bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1719bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1720bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 17218809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1722eb66ae03SLinus Torvalds if (pmd_present(pmd)) 1723a2ce2666SAaron Lu force_flush = true; 172437a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 17253592806cSKirill A. Shutemov 17261dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1727b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 17283592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 17293592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 17303592806cSKirill A. Shutemov } 1731ab6e3d09SNaoya Horiguchi pmd = move_soft_dirty_pmd(pmd); 1732ab6e3d09SNaoya Horiguchi set_pmd_at(mm, new_addr, new_pmd, pmd); 17335d190420SAaron Lu if (force_flush) 17347c38f181SMiaohe Lin flush_pmd_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 1735eb66ae03SLinus Torvalds if (new_ptl != old_ptl) 1736eb66ae03SLinus Torvalds spin_unlock(new_ptl); 1737bf929152SKirill A. Shutemov spin_unlock(old_ptl); 17384b471e88SKirill A. Shutemov return true; 173937a1c49aSAndrea Arcangeli } 17404b471e88SKirill A. Shutemov return false; 174137a1c49aSAndrea Arcangeli } 174237a1c49aSAndrea Arcangeli 1743f123d74aSMel Gorman /* 1744f123d74aSMel Gorman * Returns 1745f123d74aSMel Gorman * - 0 if PMD could not be locked 1746f0953a1bSIngo Molnar * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary 1747e346e668SYang Shi * or if prot_numa but THP migration is not supported 1748f0953a1bSIngo Molnar * - HPAGE_PMD_NR if protections changed and TLB flush necessary 1749f123d74aSMel Gorman */ 17504a18419fSNadav Amit int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 17514a18419fSNadav Amit pmd_t *pmd, unsigned long addr, pgprot_t newprot, 17524a18419fSNadav Amit unsigned long cp_flags) 1753cd7548abSJohannes Weiner { 1754cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 1755bf929152SKirill A. Shutemov spinlock_t *ptl; 1756c9fe6656SNadav Amit pmd_t oldpmd, entry; 17570a85e51dSKirill A. Shutemov bool preserve_write; 17580a85e51dSKirill A. Shutemov int ret; 175958705444SPeter Xu bool prot_numa = cp_flags & MM_CP_PROT_NUMA; 1760292924b2SPeter Xu bool uffd_wp = cp_flags & MM_CP_UFFD_WP; 1761292924b2SPeter Xu bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; 1762cd7548abSJohannes Weiner 17634a18419fSNadav Amit tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 17644a18419fSNadav Amit 1765e346e668SYang Shi if (prot_numa && !thp_migration_supported()) 1766e346e668SYang Shi return 1; 1767e346e668SYang Shi 1768b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 17690a85e51dSKirill A. Shutemov if (!ptl) 17700a85e51dSKirill A. Shutemov return 0; 17710a85e51dSKirill A. Shutemov 17720a85e51dSKirill A. Shutemov preserve_write = prot_numa && pmd_write(*pmd); 1773ba68bc01SMel Gorman ret = 1; 1774e944fd67SMel Gorman 177584c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 177684c3fc4eSZi Yan if (is_swap_pmd(*pmd)) { 177784c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(*pmd); 17786c287605SDavid Hildenbrand struct page *page = pfn_swap_entry_to_page(entry); 177984c3fc4eSZi Yan 178084c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd)); 17814dd845b5SAlistair Popple if (is_writable_migration_entry(entry)) { 178284c3fc4eSZi Yan pmd_t newpmd; 178384c3fc4eSZi Yan /* 178484c3fc4eSZi Yan * A protection check is difficult so 178584c3fc4eSZi Yan * just be safe and disable write 178684c3fc4eSZi Yan */ 17876c287605SDavid Hildenbrand if (PageAnon(page)) 17886c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(swp_offset(entry)); 17896c287605SDavid Hildenbrand else 17906c287605SDavid Hildenbrand entry = make_readable_migration_entry(swp_offset(entry)); 179184c3fc4eSZi Yan newpmd = swp_entry_to_pmd(entry); 1792ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pmd)) 1793ab6e3d09SNaoya Horiguchi newpmd = pmd_swp_mksoft_dirty(newpmd); 17948f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*pmd)) 17958f34f1eaSPeter Xu newpmd = pmd_swp_mkuffd_wp(newpmd); 179684c3fc4eSZi Yan set_pmd_at(mm, addr, pmd, newpmd); 179784c3fc4eSZi Yan } 179884c3fc4eSZi Yan goto unlock; 179984c3fc4eSZi Yan } 180084c3fc4eSZi Yan #endif 180184c3fc4eSZi Yan 1802a1a3a2fcSHuang Ying if (prot_numa) { 1803a1a3a2fcSHuang Ying struct page *page; 1804e944fd67SMel Gorman /* 1805e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 1806e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 1807e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 1808e944fd67SMel Gorman */ 1809a1a3a2fcSHuang Ying if (is_huge_zero_pmd(*pmd)) 18100a85e51dSKirill A. Shutemov goto unlock; 1811e944fd67SMel Gorman 1812a1a3a2fcSHuang Ying if (pmd_protnone(*pmd)) 18130a85e51dSKirill A. Shutemov goto unlock; 18140a85e51dSKirill A. Shutemov 1815a1a3a2fcSHuang Ying page = pmd_page(*pmd); 1816a1a3a2fcSHuang Ying /* 1817a1a3a2fcSHuang Ying * Skip scanning top tier node if normal numa 1818a1a3a2fcSHuang Ying * balancing is disabled 1819a1a3a2fcSHuang Ying */ 1820a1a3a2fcSHuang Ying if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && 1821a1a3a2fcSHuang Ying node_is_toptier(page_to_nid(page))) 1822a1a3a2fcSHuang Ying goto unlock; 1823a1a3a2fcSHuang Ying } 1824ced10803SKirill A. Shutemov /* 18253e4e28c5SMichel Lespinasse * In case prot_numa, we are under mmap_read_lock(mm). It's critical 1826ced10803SKirill A. Shutemov * to not clear pmd intermittently to avoid race with MADV_DONTNEED 18273e4e28c5SMichel Lespinasse * which is also under mmap_read_lock(mm): 1828ced10803SKirill A. Shutemov * 1829ced10803SKirill A. Shutemov * CPU0: CPU1: 1830ced10803SKirill A. Shutemov * change_huge_pmd(prot_numa=1) 1831ced10803SKirill A. Shutemov * pmdp_huge_get_and_clear_notify() 1832ced10803SKirill A. Shutemov * madvise_dontneed() 1833ced10803SKirill A. Shutemov * zap_pmd_range() 1834ced10803SKirill A. Shutemov * pmd_trans_huge(*pmd) == 0 (without ptl) 1835ced10803SKirill A. Shutemov * // skip the pmd 1836ced10803SKirill A. Shutemov * set_pmd_at(); 1837ced10803SKirill A. Shutemov * // pmd is re-established 1838ced10803SKirill A. Shutemov * 1839ced10803SKirill A. Shutemov * The race makes MADV_DONTNEED miss the huge pmd and don't clear it 1840ced10803SKirill A. Shutemov * which may break userspace. 1841ced10803SKirill A. Shutemov * 18424f831457SNadav Amit * pmdp_invalidate_ad() is required to make sure we don't miss 1843ced10803SKirill A. Shutemov * dirty/young flags set by hardware. 1844ced10803SKirill A. Shutemov */ 18454f831457SNadav Amit oldpmd = pmdp_invalidate_ad(vma, addr, pmd); 1846ced10803SKirill A. Shutemov 1847c9fe6656SNadav Amit entry = pmd_modify(oldpmd, newprot); 1848b191f9b1SMel Gorman if (preserve_write) 1849288bc549SAneesh Kumar K.V entry = pmd_mk_savedwrite(entry); 1850292924b2SPeter Xu if (uffd_wp) { 1851292924b2SPeter Xu entry = pmd_wrprotect(entry); 1852292924b2SPeter Xu entry = pmd_mkuffd_wp(entry); 1853292924b2SPeter Xu } else if (uffd_wp_resolve) { 1854292924b2SPeter Xu /* 1855292924b2SPeter Xu * Leave the write bit to be handled by PF interrupt 1856292924b2SPeter Xu * handler, then things like COW could be properly 1857292924b2SPeter Xu * handled. 1858292924b2SPeter Xu */ 1859292924b2SPeter Xu entry = pmd_clear_uffd_wp(entry); 1860292924b2SPeter Xu } 1861f123d74aSMel Gorman ret = HPAGE_PMD_NR; 186256eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 18634a18419fSNadav Amit 1864c9fe6656SNadav Amit if (huge_pmd_needs_flush(oldpmd, entry)) 18654a18419fSNadav Amit tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); 18664a18419fSNadav Amit 18670a85e51dSKirill A. Shutemov BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); 18680a85e51dSKirill A. Shutemov unlock: 1869bf929152SKirill A. Shutemov spin_unlock(ptl); 1870cd7548abSJohannes Weiner return ret; 1871cd7548abSJohannes Weiner } 1872cd7548abSJohannes Weiner 1873025c5b24SNaoya Horiguchi /* 18748f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 1875025c5b24SNaoya Horiguchi * 18768f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 18778f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 1878025c5b24SNaoya Horiguchi */ 1879b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 1880025c5b24SNaoya Horiguchi { 1881b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 1882b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 188384c3fc4eSZi Yan if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || 188484c3fc4eSZi Yan pmd_devmap(*pmd))) 1885b6ec57f4SKirill A. Shutemov return ptl; 1886b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 1887b6ec57f4SKirill A. Shutemov return NULL; 1888025c5b24SNaoya Horiguchi } 1889025c5b24SNaoya Horiguchi 1890a00cc7d9SMatthew Wilcox /* 1891d965e390SMiaohe Lin * Returns page table lock pointer if a given pud maps a thp, NULL otherwise. 1892a00cc7d9SMatthew Wilcox * 1893d965e390SMiaohe Lin * Note that if it returns page table lock pointer, this routine returns without 1894d965e390SMiaohe Lin * unlocking page table lock. So callers must unlock it. 1895a00cc7d9SMatthew Wilcox */ 1896a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 1897a00cc7d9SMatthew Wilcox { 1898a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1899a00cc7d9SMatthew Wilcox 1900a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 1901a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 1902a00cc7d9SMatthew Wilcox return ptl; 1903a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1904a00cc7d9SMatthew Wilcox return NULL; 1905a00cc7d9SMatthew Wilcox } 1906a00cc7d9SMatthew Wilcox 1907a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1908a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 1909a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 1910a00cc7d9SMatthew Wilcox { 1911a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1912a00cc7d9SMatthew Wilcox 1913a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 1914a00cc7d9SMatthew Wilcox if (!ptl) 1915a00cc7d9SMatthew Wilcox return 0; 191674929079SMiaohe Lin 191770516b93SQian Cai pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); 1918a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 19192484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 1920a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1921a00cc7d9SMatthew Wilcox /* No zero page support yet */ 1922a00cc7d9SMatthew Wilcox } else { 1923a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 1924a00cc7d9SMatthew Wilcox BUG(); 1925a00cc7d9SMatthew Wilcox } 1926a00cc7d9SMatthew Wilcox return 1; 1927a00cc7d9SMatthew Wilcox } 1928a00cc7d9SMatthew Wilcox 1929a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 1930a00cc7d9SMatthew Wilcox unsigned long haddr) 1931a00cc7d9SMatthew Wilcox { 1932a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 1933a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 1934a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 1935a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 1936a00cc7d9SMatthew Wilcox 1937ce9311cfSYisheng Xie count_vm_event(THP_SPLIT_PUD); 1938a00cc7d9SMatthew Wilcox 1939a00cc7d9SMatthew Wilcox pudp_huge_clear_flush_notify(vma, haddr, pud); 1940a00cc7d9SMatthew Wilcox } 1941a00cc7d9SMatthew Wilcox 1942a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 1943a00cc7d9SMatthew Wilcox unsigned long address) 1944a00cc7d9SMatthew Wilcox { 1945a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1946ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 1947a00cc7d9SMatthew Wilcox 19487269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 19496f4f13e8SJérôme Glisse address & HPAGE_PUD_MASK, 1950ac46d4f3SJérôme Glisse (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); 1951ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 1952ac46d4f3SJérôme Glisse ptl = pud_lock(vma->vm_mm, pud); 1953a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 1954a00cc7d9SMatthew Wilcox goto out; 1955ac46d4f3SJérôme Glisse __split_huge_pud_locked(vma, pud, range.start); 1956a00cc7d9SMatthew Wilcox 1957a00cc7d9SMatthew Wilcox out: 1958a00cc7d9SMatthew Wilcox spin_unlock(ptl); 19594645b9feSJérôme Glisse /* 19604645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 19614645b9feSJérôme Glisse * the above pudp_huge_clear_flush_notify() did already call it. 19624645b9feSJérôme Glisse */ 1963ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 1964a00cc7d9SMatthew Wilcox } 1965a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1966a00cc7d9SMatthew Wilcox 1967eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 1968eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 1969eef1b3baSKirill A. Shutemov { 1970eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 1971eef1b3baSKirill A. Shutemov pgtable_t pgtable; 1972eef1b3baSKirill A. Shutemov pmd_t _pmd; 1973eef1b3baSKirill A. Shutemov int i; 1974eef1b3baSKirill A. Shutemov 19750f10851eSJérôme Glisse /* 19760f10851eSJérôme Glisse * Leave pmd empty until pte is filled note that it is fine to delay 19770f10851eSJérôme Glisse * notification until mmu_notifier_invalidate_range_end() as we are 19780f10851eSJérôme Glisse * replacing a zero pmd write protected page with a zero pte write 19790f10851eSJérôme Glisse * protected page. 19800f10851eSJérôme Glisse * 1981ee65728eSMike Rapoport * See Documentation/mm/mmu_notifier.rst 19820f10851eSJérôme Glisse */ 19830f10851eSJérôme Glisse pmdp_huge_clear_flush(vma, haddr, pmd); 1984eef1b3baSKirill A. Shutemov 1985eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1986eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 1987eef1b3baSKirill A. Shutemov 1988eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { 1989eef1b3baSKirill A. Shutemov pte_t *pte, entry; 1990eef1b3baSKirill A. Shutemov entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); 1991eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 1992eef1b3baSKirill A. Shutemov pte = pte_offset_map(&_pmd, haddr); 1993eef1b3baSKirill A. Shutemov VM_BUG_ON(!pte_none(*pte)); 1994eef1b3baSKirill A. Shutemov set_pte_at(mm, haddr, pte, entry); 1995eef1b3baSKirill A. Shutemov pte_unmap(pte); 1996eef1b3baSKirill A. Shutemov } 1997eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 1998eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 1999eef1b3baSKirill A. Shutemov } 2000eef1b3baSKirill A. Shutemov 2001eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 2002ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 2003eef1b3baSKirill A. Shutemov { 2004eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2005eef1b3baSKirill A. Shutemov struct page *page; 2006eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2007423ac9afSAneesh Kumar K.V pmd_t old_pmd, _pmd; 2008292924b2SPeter Xu bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; 20096c287605SDavid Hildenbrand bool anon_exclusive = false; 20102ac015e2SKirill A. Shutemov unsigned long addr; 2011eef1b3baSKirill A. Shutemov int i; 2012eef1b3baSKirill A. Shutemov 2013eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 2014eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2015eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 201684c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) 201784c3fc4eSZi Yan && !pmd_devmap(*pmd)); 2018eef1b3baSKirill A. Shutemov 2019eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 2020eef1b3baSKirill A. Shutemov 2021d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 202299fa8a48SHugh Dickins old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); 2023953c66c2SAneesh Kumar K.V /* 2024953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 2025953c66c2SAneesh Kumar K.V * just go ahead and zap it 2026953c66c2SAneesh Kumar K.V */ 2027953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 2028953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 20292484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) 2030d21b9e57SKirill A. Shutemov return; 203199fa8a48SHugh Dickins if (unlikely(is_pmd_migration_entry(old_pmd))) { 203299fa8a48SHugh Dickins swp_entry_t entry; 203399fa8a48SHugh Dickins 203499fa8a48SHugh Dickins entry = pmd_to_swp_entry(old_pmd); 2035af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 203699fa8a48SHugh Dickins } else { 203799fa8a48SHugh Dickins page = pmd_page(old_pmd); 203899fa8a48SHugh Dickins if (!PageDirty(page) && pmd_dirty(old_pmd)) 2039e1f1b157SHugh Dickins set_page_dirty(page); 204099fa8a48SHugh Dickins if (!PageReferenced(page) && pmd_young(old_pmd)) 2041d21b9e57SKirill A. Shutemov SetPageReferenced(page); 2042cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 2043d21b9e57SKirill A. Shutemov put_page(page); 204499fa8a48SHugh Dickins } 2045fadae295SYang Shi add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); 2046eef1b3baSKirill A. Shutemov return; 204799fa8a48SHugh Dickins } 204899fa8a48SHugh Dickins 20493b77e8c8SHugh Dickins if (is_huge_zero_pmd(*pmd)) { 20504645b9feSJérôme Glisse /* 20514645b9feSJérôme Glisse * FIXME: Do we want to invalidate secondary mmu by calling 20524645b9feSJérôme Glisse * mmu_notifier_invalidate_range() see comments below inside 20534645b9feSJérôme Glisse * __split_huge_pmd() ? 20544645b9feSJérôme Glisse * 20554645b9feSJérôme Glisse * We are going from a zero huge page write protected to zero 20564645b9feSJérôme Glisse * small page also write protected so it does not seems useful 20574645b9feSJérôme Glisse * to invalidate secondary mmu at this time. 20584645b9feSJérôme Glisse */ 2059eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 2060eef1b3baSKirill A. Shutemov } 2061eef1b3baSKirill A. Shutemov 2062423ac9afSAneesh Kumar K.V /* 2063423ac9afSAneesh Kumar K.V * Up to this point the pmd is present and huge and userland has the 2064423ac9afSAneesh Kumar K.V * whole access to the hugepage during the split (which happens in 2065423ac9afSAneesh Kumar K.V * place). If we overwrite the pmd with the not-huge version pointing 2066423ac9afSAneesh Kumar K.V * to the pte here (which of course we could if all CPUs were bug 2067423ac9afSAneesh Kumar K.V * free), userland could trigger a small page size TLB miss on the 2068423ac9afSAneesh Kumar K.V * small sized TLB while the hugepage TLB entry is still established in 2069423ac9afSAneesh Kumar K.V * the huge TLB. Some CPU doesn't like that. 207042742d9bSAlexander A. Klimov * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum 207142742d9bSAlexander A. Klimov * 383 on page 105. Intel should be safe but is also warns that it's 2072423ac9afSAneesh Kumar K.V * only safe if the permission and cache attributes of the two entries 2073423ac9afSAneesh Kumar K.V * loaded in the two TLB is identical (which should be the case here). 2074423ac9afSAneesh Kumar K.V * But it is generally safer to never allow small and huge TLB entries 2075423ac9afSAneesh Kumar K.V * for the same virtual address to be loaded simultaneously. So instead 2076423ac9afSAneesh Kumar K.V * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2077423ac9afSAneesh Kumar K.V * current pmd notpresent (atomically because here the pmd_trans_huge 2078423ac9afSAneesh Kumar K.V * must remain set at all times on the pmd until the split is complete 2079423ac9afSAneesh Kumar K.V * for this pmd), then we flush the SMP TLB and finally we write the 2080423ac9afSAneesh Kumar K.V * non-huge version of the pmd entry with pmd_populate. 2081423ac9afSAneesh Kumar K.V */ 2082423ac9afSAneesh Kumar K.V old_pmd = pmdp_invalidate(vma, haddr, pmd); 2083423ac9afSAneesh Kumar K.V 2084423ac9afSAneesh Kumar K.V pmd_migration = is_pmd_migration_entry(old_pmd); 20852e83ee1dSPeter Xu if (unlikely(pmd_migration)) { 208684c3fc4eSZi Yan swp_entry_t entry; 208784c3fc4eSZi Yan 2088423ac9afSAneesh Kumar K.V entry = pmd_to_swp_entry(old_pmd); 2089af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 20904dd845b5SAlistair Popple write = is_writable_migration_entry(entry); 20916c287605SDavid Hildenbrand if (PageAnon(page)) 20926c287605SDavid Hildenbrand anon_exclusive = is_readable_exclusive_migration_entry(entry); 20932e83ee1dSPeter Xu young = false; 20942e83ee1dSPeter Xu soft_dirty = pmd_swp_soft_dirty(old_pmd); 2095f45ec5ffSPeter Xu uffd_wp = pmd_swp_uffd_wp(old_pmd); 20962e83ee1dSPeter Xu } else { 2097423ac9afSAneesh Kumar K.V page = pmd_page(old_pmd); 2098423ac9afSAneesh Kumar K.V if (pmd_dirty(old_pmd)) 2099423ac9afSAneesh Kumar K.V SetPageDirty(page); 2100423ac9afSAneesh Kumar K.V write = pmd_write(old_pmd); 2101423ac9afSAneesh Kumar K.V young = pmd_young(old_pmd); 2102423ac9afSAneesh Kumar K.V soft_dirty = pmd_soft_dirty(old_pmd); 2103292924b2SPeter Xu uffd_wp = pmd_uffd_wp(old_pmd); 21046c287605SDavid Hildenbrand 21052e83ee1dSPeter Xu VM_BUG_ON_PAGE(!page_count(page), page); 21062e83ee1dSPeter Xu page_ref_add(page, HPAGE_PMD_NR - 1); 21076c287605SDavid Hildenbrand 21086c287605SDavid Hildenbrand /* 21096c287605SDavid Hildenbrand * Without "freeze", we'll simply split the PMD, propagating the 21106c287605SDavid Hildenbrand * PageAnonExclusive() flag for each PTE by setting it for 21116c287605SDavid Hildenbrand * each subpage -- no need to (temporarily) clear. 21126c287605SDavid Hildenbrand * 21136c287605SDavid Hildenbrand * With "freeze" we want to replace mapped pages by 21146c287605SDavid Hildenbrand * migration entries right away. This is only possible if we 21156c287605SDavid Hildenbrand * managed to clear PageAnonExclusive() -- see 21166c287605SDavid Hildenbrand * set_pmd_migration_entry(). 21176c287605SDavid Hildenbrand * 21186c287605SDavid Hildenbrand * In case we cannot clear PageAnonExclusive(), split the PMD 21196c287605SDavid Hildenbrand * only and let try_to_migrate_one() fail later. 21206c287605SDavid Hildenbrand */ 21216c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 21226c287605SDavid Hildenbrand if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) 21236c287605SDavid Hildenbrand freeze = false; 21249d84604bSHugh Dickins } 2125eef1b3baSKirill A. Shutemov 2126423ac9afSAneesh Kumar K.V /* 2127423ac9afSAneesh Kumar K.V * Withdraw the table only after we mark the pmd entry invalid. 2128423ac9afSAneesh Kumar K.V * This's critical for some architectures (Power). 2129423ac9afSAneesh Kumar K.V */ 2130eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2131eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2132eef1b3baSKirill A. Shutemov 21332ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2134eef1b3baSKirill A. Shutemov pte_t entry, *pte; 2135eef1b3baSKirill A. Shutemov /* 2136eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 2137eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 2138eef1b3baSKirill A. Shutemov * permissions across VMAs. 2139eef1b3baSKirill A. Shutemov */ 214084c3fc4eSZi Yan if (freeze || pmd_migration) { 2141ba988280SKirill A. Shutemov swp_entry_t swp_entry; 21424dd845b5SAlistair Popple if (write) 21434dd845b5SAlistair Popple swp_entry = make_writable_migration_entry( 21444dd845b5SAlistair Popple page_to_pfn(page + i)); 21456c287605SDavid Hildenbrand else if (anon_exclusive) 21466c287605SDavid Hildenbrand swp_entry = make_readable_exclusive_migration_entry( 21476c287605SDavid Hildenbrand page_to_pfn(page + i)); 21484dd845b5SAlistair Popple else 21494dd845b5SAlistair Popple swp_entry = make_readable_migration_entry( 21504dd845b5SAlistair Popple page_to_pfn(page + i)); 2151ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 2152804dd150SAndrea Arcangeli if (soft_dirty) 2153804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 2154f45ec5ffSPeter Xu if (uffd_wp) 2155f45ec5ffSPeter Xu entry = pte_swp_mkuffd_wp(entry); 2156ba988280SKirill A. Shutemov } else { 21576d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 2158b8d3c4c3SMinchan Kim entry = maybe_mkwrite(entry, vma); 21596c287605SDavid Hildenbrand if (anon_exclusive) 21606c287605SDavid Hildenbrand SetPageAnonExclusive(page + i); 2161eef1b3baSKirill A. Shutemov if (!write) 2162eef1b3baSKirill A. Shutemov entry = pte_wrprotect(entry); 2163eef1b3baSKirill A. Shutemov if (!young) 2164eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 2165804dd150SAndrea Arcangeli if (soft_dirty) 2166804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 2167292924b2SPeter Xu if (uffd_wp) 2168292924b2SPeter Xu entry = pte_mkuffd_wp(entry); 2169ba988280SKirill A. Shutemov } 21702ac015e2SKirill A. Shutemov pte = pte_offset_map(&_pmd, addr); 2171eef1b3baSKirill A. Shutemov BUG_ON(!pte_none(*pte)); 21722ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 2173ec0abae6SRalph Campbell if (!pmd_migration) 2174eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 2175eef1b3baSKirill A. Shutemov pte_unmap(pte); 2176eef1b3baSKirill A. Shutemov } 2177eef1b3baSKirill A. Shutemov 2178ec0abae6SRalph Campbell if (!pmd_migration) { 2179eef1b3baSKirill A. Shutemov /* 2180eef1b3baSKirill A. Shutemov * Set PG_double_map before dropping compound_mapcount to avoid 2181eef1b3baSKirill A. Shutemov * false-negative page_mapped(). 2182eef1b3baSKirill A. Shutemov */ 2183ec0abae6SRalph Campbell if (compound_mapcount(page) > 1 && 2184ec0abae6SRalph Campbell !TestSetPageDoubleMap(page)) { 2185eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2186eef1b3baSKirill A. Shutemov atomic_inc(&page[i]._mapcount); 2187eef1b3baSKirill A. Shutemov } 2188eef1b3baSKirill A. Shutemov 2189468c3982SJohannes Weiner lock_page_memcg(page); 2190eef1b3baSKirill A. Shutemov if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { 2191eef1b3baSKirill A. Shutemov /* Last compound_mapcount is gone. */ 219269473e5dSMuchun Song __mod_lruvec_page_state(page, NR_ANON_THPS, 219369473e5dSMuchun Song -HPAGE_PMD_NR); 2194eef1b3baSKirill A. Shutemov if (TestClearPageDoubleMap(page)) { 2195eef1b3baSKirill A. Shutemov /* No need in mapcount reference anymore */ 2196eef1b3baSKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 2197eef1b3baSKirill A. Shutemov atomic_dec(&page[i]._mapcount); 2198eef1b3baSKirill A. Shutemov } 2199eef1b3baSKirill A. Shutemov } 2200468c3982SJohannes Weiner unlock_page_memcg(page); 2201cea86fe2SHugh Dickins 2202cea86fe2SHugh Dickins /* Above is effectively page_remove_rmap(page, vma, true) */ 2203cea86fe2SHugh Dickins munlock_vma_page(page, vma, true); 2204ec0abae6SRalph Campbell } 2205eef1b3baSKirill A. Shutemov 2206eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2207eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2208e9b61f19SKirill A. Shutemov 2209e9b61f19SKirill A. Shutemov if (freeze) { 22102ac015e2SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) { 2211cea86fe2SHugh Dickins page_remove_rmap(page + i, vma, false); 2212e9b61f19SKirill A. Shutemov put_page(page + i); 2213e9b61f19SKirill A. Shutemov } 2214e9b61f19SKirill A. Shutemov } 2215eef1b3baSKirill A. Shutemov } 2216eef1b3baSKirill A. Shutemov 2217eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 2218af28a988SMatthew Wilcox (Oracle) unsigned long address, bool freeze, struct folio *folio) 2219eef1b3baSKirill A. Shutemov { 2220eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2221ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2222eef1b3baSKirill A. Shutemov 22237269f999SJérôme Glisse mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, 22246f4f13e8SJérôme Glisse address & HPAGE_PMD_MASK, 2225ac46d4f3SJérôme Glisse (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); 2226ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2227ac46d4f3SJérôme Glisse ptl = pmd_lock(vma->vm_mm, pmd); 222833f4751eSNaoya Horiguchi 222933f4751eSNaoya Horiguchi /* 2230af28a988SMatthew Wilcox (Oracle) * If caller asks to setup a migration entry, we need a folio to check 2231af28a988SMatthew Wilcox (Oracle) * pmd against. Otherwise we can end up replacing wrong folio. 223233f4751eSNaoya Horiguchi */ 2233af28a988SMatthew Wilcox (Oracle) VM_BUG_ON(freeze && !folio); 223483a8441fSMatthew Wilcox (Oracle) VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); 223533f4751eSNaoya Horiguchi 22367f760917SDavid Hildenbrand if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || 223783a8441fSMatthew Wilcox (Oracle) is_pmd_migration_entry(*pmd)) { 223883a8441fSMatthew Wilcox (Oracle) if (folio && folio != page_folio(pmd_page(*pmd))) 223983a8441fSMatthew Wilcox (Oracle) goto out; 2240ac46d4f3SJérôme Glisse __split_huge_pmd_locked(vma, pmd, range.start, freeze); 224183a8441fSMatthew Wilcox (Oracle) } 22427f760917SDavid Hildenbrand 2243e90309c9SKirill A. Shutemov out: 2244eef1b3baSKirill A. Shutemov spin_unlock(ptl); 22454645b9feSJérôme Glisse /* 22464645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback. 22474645b9feSJérôme Glisse * They are 3 cases to consider inside __split_huge_pmd_locked(): 22484645b9feSJérôme Glisse * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious 22494645b9feSJérôme Glisse * 2) __split_huge_zero_page_pmd() read only zero page and any write 22504645b9feSJérôme Glisse * fault will trigger a flush_notify before pointing to a new page 22514645b9feSJérôme Glisse * (it is fine if the secondary mmu keeps pointing to the old zero 22524645b9feSJérôme Glisse * page in the meantime) 22534645b9feSJérôme Glisse * 3) Split a huge pmd into pte pointing to the same page. No need 22544645b9feSJérôme Glisse * to invalidate secondary tlb entry they are all still valid. 22554645b9feSJérôme Glisse * any further changes to individual pte will notify. So no need 22564645b9feSJérôme Glisse * to call mmu_notifier->invalidate_range() 22574645b9feSJérôme Glisse */ 2258ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_only_end(&range); 2259eef1b3baSKirill A. Shutemov } 2260eef1b3baSKirill A. Shutemov 2261fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2262af28a988SMatthew Wilcox (Oracle) bool freeze, struct folio *folio) 226394fcc585SAndrea Arcangeli { 2264f72e7dcdSHugh Dickins pgd_t *pgd; 2265c2febafcSKirill A. Shutemov p4d_t *p4d; 2266f72e7dcdSHugh Dickins pud_t *pud; 226794fcc585SAndrea Arcangeli pmd_t *pmd; 226894fcc585SAndrea Arcangeli 226978ddc534SKirill A. Shutemov pgd = pgd_offset(vma->vm_mm, address); 2270f72e7dcdSHugh Dickins if (!pgd_present(*pgd)) 2271f72e7dcdSHugh Dickins return; 2272f72e7dcdSHugh Dickins 2273c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, address); 2274c2febafcSKirill A. Shutemov if (!p4d_present(*p4d)) 2275c2febafcSKirill A. Shutemov return; 2276c2febafcSKirill A. Shutemov 2277c2febafcSKirill A. Shutemov pud = pud_offset(p4d, address); 2278f72e7dcdSHugh Dickins if (!pud_present(*pud)) 2279f72e7dcdSHugh Dickins return; 2280f72e7dcdSHugh Dickins 2281f72e7dcdSHugh Dickins pmd = pmd_offset(pud, address); 2282fec89c10SKirill A. Shutemov 2283af28a988SMatthew Wilcox (Oracle) __split_huge_pmd(vma, pmd, address, freeze, folio); 228494fcc585SAndrea Arcangeli } 228594fcc585SAndrea Arcangeli 228671f9e58eSMiaohe Lin static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) 228771f9e58eSMiaohe Lin { 228871f9e58eSMiaohe Lin /* 228971f9e58eSMiaohe Lin * If the new address isn't hpage aligned and it could previously 229071f9e58eSMiaohe Lin * contain an hugepage: check if we need to split an huge pmd. 229171f9e58eSMiaohe Lin */ 229271f9e58eSMiaohe Lin if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && 229371f9e58eSMiaohe Lin range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), 229471f9e58eSMiaohe Lin ALIGN(address, HPAGE_PMD_SIZE))) 229571f9e58eSMiaohe Lin split_huge_pmd_address(vma, address, false, NULL); 229671f9e58eSMiaohe Lin } 229771f9e58eSMiaohe Lin 2298e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 229994fcc585SAndrea Arcangeli unsigned long start, 230094fcc585SAndrea Arcangeli unsigned long end, 230194fcc585SAndrea Arcangeli long adjust_next) 230294fcc585SAndrea Arcangeli { 230371f9e58eSMiaohe Lin /* Check if we need to split start first. */ 230471f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, start); 230571f9e58eSMiaohe Lin 230671f9e58eSMiaohe Lin /* Check if we need to split end next. */ 230771f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, end); 230894fcc585SAndrea Arcangeli 230994fcc585SAndrea Arcangeli /* 231071f9e58eSMiaohe Lin * If we're also updating the vma->vm_next->vm_start, 231171f9e58eSMiaohe Lin * check if we need to split it. 231294fcc585SAndrea Arcangeli */ 231394fcc585SAndrea Arcangeli if (adjust_next > 0) { 231494fcc585SAndrea Arcangeli struct vm_area_struct *next = vma->vm_next; 231594fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 2316f9d86a60SWei Yang nstart += adjust_next; 231771f9e58eSMiaohe Lin split_huge_pmd_if_needed(next, nstart); 231894fcc585SAndrea Arcangeli } 231994fcc585SAndrea Arcangeli } 2320e9b61f19SKirill A. Shutemov 2321906f9cdfSHugh Dickins static void unmap_page(struct page *page) 2322e9b61f19SKirill A. Shutemov { 2323869f7ee6SMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2324a98a2f0cSAlistair Popple enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | 2325a98a2f0cSAlistair Popple TTU_SYNC; 2326e9b61f19SKirill A. Shutemov 2327e9b61f19SKirill A. Shutemov VM_BUG_ON_PAGE(!PageHead(page), page); 2328e9b61f19SKirill A. Shutemov 2329a98a2f0cSAlistair Popple /* 2330a98a2f0cSAlistair Popple * Anon pages need migration entries to preserve them, but file 2331a98a2f0cSAlistair Popple * pages can simply be left unmapped, then faulted back on demand. 2332a98a2f0cSAlistair Popple * If that is ever changed (perhaps for mlock), update remap_page(). 2333a98a2f0cSAlistair Popple */ 23344b8554c5SMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 23354b8554c5SMatthew Wilcox (Oracle) try_to_migrate(folio, ttu_flags); 2336a98a2f0cSAlistair Popple else 2337869f7ee6SMatthew Wilcox (Oracle) try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); 2338bd56086fSKirill A. Shutemov } 2339bd56086fSKirill A. Shutemov 23404eecb8b9SMatthew Wilcox (Oracle) static void remap_page(struct folio *folio, unsigned long nr) 2341e9b61f19SKirill A. Shutemov { 23424eecb8b9SMatthew Wilcox (Oracle) int i = 0; 2343ab02c252SHugh Dickins 234464b586d1SHugh Dickins /* If unmap_page() uses try_to_migrate() on file, remove this check */ 23454eecb8b9SMatthew Wilcox (Oracle) if (!folio_test_anon(folio)) 2346ab02c252SHugh Dickins return; 23474eecb8b9SMatthew Wilcox (Oracle) for (;;) { 23484eecb8b9SMatthew Wilcox (Oracle) remove_migration_ptes(folio, folio, true); 23494eecb8b9SMatthew Wilcox (Oracle) i += folio_nr_pages(folio); 23504eecb8b9SMatthew Wilcox (Oracle) if (i >= nr) 23514eecb8b9SMatthew Wilcox (Oracle) break; 23524eecb8b9SMatthew Wilcox (Oracle) folio = folio_next(folio); 2353e9b61f19SKirill A. Shutemov } 2354ace71a19SKirill A. Shutemov } 2355e9b61f19SKirill A. Shutemov 235694866635SAlex Shi static void lru_add_page_tail(struct page *head, struct page *tail, 235788dcb9a3SAlex Shi struct lruvec *lruvec, struct list_head *list) 235888dcb9a3SAlex Shi { 235994866635SAlex Shi VM_BUG_ON_PAGE(!PageHead(head), head); 236094866635SAlex Shi VM_BUG_ON_PAGE(PageCompound(tail), head); 236194866635SAlex Shi VM_BUG_ON_PAGE(PageLRU(tail), head); 23626168d0daSAlex Shi lockdep_assert_held(&lruvec->lru_lock); 236388dcb9a3SAlex Shi 23646dbb5741SAlex Shi if (list) { 236588dcb9a3SAlex Shi /* page reclaim is reclaiming a huge page */ 23666dbb5741SAlex Shi VM_WARN_ON(PageLRU(head)); 236794866635SAlex Shi get_page(tail); 236894866635SAlex Shi list_add_tail(&tail->lru, list); 236988dcb9a3SAlex Shi } else { 23706dbb5741SAlex Shi /* head is still on lru (and we have it frozen) */ 23716dbb5741SAlex Shi VM_WARN_ON(!PageLRU(head)); 237207ca7606SHugh Dickins if (PageUnevictable(tail)) 237307ca7606SHugh Dickins tail->mlock_count = 0; 237407ca7606SHugh Dickins else 23756dbb5741SAlex Shi list_add_tail(&tail->lru, &head->lru); 237607ca7606SHugh Dickins SetPageLRU(tail); 237788dcb9a3SAlex Shi } 237888dcb9a3SAlex Shi } 237988dcb9a3SAlex Shi 23808df651c7SKirill A. Shutemov static void __split_huge_page_tail(struct page *head, int tail, 2381e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2382e9b61f19SKirill A. Shutemov { 2383e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 2384e9b61f19SKirill A. Shutemov 23858df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2386e9b61f19SKirill A. Shutemov 2387e9b61f19SKirill A. Shutemov /* 2388605ca5edSKonstantin Khlebnikov * Clone page flags before unfreezing refcount. 2389605ca5edSKonstantin Khlebnikov * 2390605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow flags change, 23918958b249SHaitao Shi * for example lock_page() which set PG_waiters. 23926c287605SDavid Hildenbrand * 23936c287605SDavid Hildenbrand * Note that for mapped sub-pages of an anonymous THP, 23946c287605SDavid Hildenbrand * PG_anon_exclusive has been cleared in unmap_page() and is stored in 23956c287605SDavid Hildenbrand * the migration entry instead from where remap_page() will restore it. 23966c287605SDavid Hildenbrand * We can still have PG_anon_exclusive set on effectively unmapped and 23976c287605SDavid Hildenbrand * unreferenced sub-pages of an anonymous THP: we can simply drop 23986c287605SDavid Hildenbrand * PG_anon_exclusive (-> PG_mappedtodisk) for these here. 2399e9b61f19SKirill A. Shutemov */ 2400e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2401e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2402e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2403e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 240438d8b4e6SHuang Ying (1L << PG_swapcache) | 2405e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2406e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2407e9b61f19SKirill A. Shutemov (1L << PG_active) | 24081899ad18SJohannes Weiner (1L << PG_workingset) | 2409e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2410b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 241172e6afa0SCatalin Marinas #ifdef CONFIG_64BIT 241272e6afa0SCatalin Marinas (1L << PG_arch_2) | 241372e6afa0SCatalin Marinas #endif 2414b8d3c4c3SMinchan Kim (1L << PG_dirty))); 2415e9b61f19SKirill A. Shutemov 2416173d9d9fSHugh Dickins /* ->mapping in first tail page is compound_mapcount */ 2417173d9d9fSHugh Dickins VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2418173d9d9fSHugh Dickins page_tail); 2419173d9d9fSHugh Dickins page_tail->mapping = head->mapping; 2420173d9d9fSHugh Dickins page_tail->index = head->index + tail; 2421b653db77SMatthew Wilcox (Oracle) page_tail->private = 0; 2422173d9d9fSHugh Dickins 2423605ca5edSKonstantin Khlebnikov /* Page flags must be visible before we make the page non-compound. */ 2424e9b61f19SKirill A. Shutemov smp_wmb(); 2425e9b61f19SKirill A. Shutemov 2426605ca5edSKonstantin Khlebnikov /* 2427605ca5edSKonstantin Khlebnikov * Clear PageTail before unfreezing page refcount. 2428605ca5edSKonstantin Khlebnikov * 2429605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow put_page() 2430605ca5edSKonstantin Khlebnikov * which needs correct compound_head(). 2431605ca5edSKonstantin Khlebnikov */ 2432e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2433e9b61f19SKirill A. Shutemov 2434605ca5edSKonstantin Khlebnikov /* Finally unfreeze refcount. Additional reference from page cache. */ 2435605ca5edSKonstantin Khlebnikov page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || 2436605ca5edSKonstantin Khlebnikov PageSwapCache(head))); 2437605ca5edSKonstantin Khlebnikov 2438e9b61f19SKirill A. Shutemov if (page_is_young(head)) 2439e9b61f19SKirill A. Shutemov set_page_young(page_tail); 2440e9b61f19SKirill A. Shutemov if (page_is_idle(head)) 2441e9b61f19SKirill A. Shutemov set_page_idle(page_tail); 2442e9b61f19SKirill A. Shutemov 2443e9b61f19SKirill A. Shutemov page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); 244494723aafSMichal Hocko 244594723aafSMichal Hocko /* 244694723aafSMichal Hocko * always add to the tail because some iterators expect new 244794723aafSMichal Hocko * pages to show after the currently processed elements - e.g. 244894723aafSMichal Hocko * migrate_pages 244994723aafSMichal Hocko */ 2450e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2451e9b61f19SKirill A. Shutemov } 2452e9b61f19SKirill A. Shutemov 2453baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2454b6769834SAlex Shi pgoff_t end) 2455e9b61f19SKirill A. Shutemov { 2456e809c3feSMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2457e809c3feSMatthew Wilcox (Oracle) struct page *head = &folio->page; 2458e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 24594101196bSMatthew Wilcox (Oracle) struct address_space *swap_cache = NULL; 24604101196bSMatthew Wilcox (Oracle) unsigned long offset = 0; 24618cce5475SKirill A. Shutemov unsigned int nr = thp_nr_pages(head); 24628df651c7SKirill A. Shutemov int i; 2463e9b61f19SKirill A. Shutemov 2464e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2465be6c8982SZhou Guanghui split_page_memcg(head, nr); 2466e9b61f19SKirill A. Shutemov 24674101196bSMatthew Wilcox (Oracle) if (PageAnon(head) && PageSwapCache(head)) { 24684101196bSMatthew Wilcox (Oracle) swp_entry_t entry = { .val = page_private(head) }; 24694101196bSMatthew Wilcox (Oracle) 24704101196bSMatthew Wilcox (Oracle) offset = swp_offset(entry); 24714101196bSMatthew Wilcox (Oracle) swap_cache = swap_address_space(entry); 24724101196bSMatthew Wilcox (Oracle) xa_lock(&swap_cache->i_pages); 24734101196bSMatthew Wilcox (Oracle) } 24744101196bSMatthew Wilcox (Oracle) 2475f0953a1bSIngo Molnar /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ 2476e809c3feSMatthew Wilcox (Oracle) lruvec = folio_lruvec_lock(folio); 2477b6769834SAlex Shi 2478eac96c3eSYang Shi ClearPageHasHWPoisoned(head); 2479eac96c3eSYang Shi 24808cce5475SKirill A. Shutemov for (i = nr - 1; i >= 1; i--) { 24818df651c7SKirill A. Shutemov __split_huge_page_tail(head, i, lruvec, list); 2482d144bf62SHugh Dickins /* Some pages can be beyond EOF: drop them from page cache */ 2483baa355fdSKirill A. Shutemov if (head[i].index >= end) { 24842d077d4bSHugh Dickins ClearPageDirty(head + i); 2485baa355fdSKirill A. Shutemov __delete_from_page_cache(head + i, NULL); 2486d144bf62SHugh Dickins if (shmem_mapping(head->mapping)) 2487800d8c63SKirill A. Shutemov shmem_uncharge(head->mapping->host, 1); 2488baa355fdSKirill A. Shutemov put_page(head + i); 24894101196bSMatthew Wilcox (Oracle) } else if (!PageAnon(page)) { 24904101196bSMatthew Wilcox (Oracle) __xa_store(&head->mapping->i_pages, head[i].index, 24914101196bSMatthew Wilcox (Oracle) head + i, 0); 24924101196bSMatthew Wilcox (Oracle) } else if (swap_cache) { 24934101196bSMatthew Wilcox (Oracle) __xa_store(&swap_cache->i_pages, offset + i, 24944101196bSMatthew Wilcox (Oracle) head + i, 0); 2495baa355fdSKirill A. Shutemov } 2496baa355fdSKirill A. Shutemov } 2497e9b61f19SKirill A. Shutemov 2498e9b61f19SKirill A. Shutemov ClearPageCompound(head); 24996168d0daSAlex Shi unlock_page_lruvec(lruvec); 2500b6769834SAlex Shi /* Caller disabled irqs, so they are still disabled here */ 2501f7da677bSVlastimil Babka 25028cce5475SKirill A. Shutemov split_page_owner(head, nr); 2503f7da677bSVlastimil Babka 2504baa355fdSKirill A. Shutemov /* See comment in __split_huge_page_tail() */ 2505baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2506aa5dc07fSMatthew Wilcox /* Additional pin to swap cache */ 25074101196bSMatthew Wilcox (Oracle) if (PageSwapCache(head)) { 250838d8b4e6SHuang Ying page_ref_add(head, 2); 25094101196bSMatthew Wilcox (Oracle) xa_unlock(&swap_cache->i_pages); 25104101196bSMatthew Wilcox (Oracle) } else { 2511baa355fdSKirill A. Shutemov page_ref_inc(head); 25124101196bSMatthew Wilcox (Oracle) } 2513baa355fdSKirill A. Shutemov } else { 2514aa5dc07fSMatthew Wilcox /* Additional pin to page cache */ 2515baa355fdSKirill A. Shutemov page_ref_add(head, 2); 2516b93b0163SMatthew Wilcox xa_unlock(&head->mapping->i_pages); 2517baa355fdSKirill A. Shutemov } 2518b6769834SAlex Shi local_irq_enable(); 2519e9b61f19SKirill A. Shutemov 25204eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, nr); 2521e9b61f19SKirill A. Shutemov 2522c4f9c701SHuang Ying if (PageSwapCache(head)) { 2523c4f9c701SHuang Ying swp_entry_t entry = { .val = page_private(head) }; 2524c4f9c701SHuang Ying 2525c4f9c701SHuang Ying split_swap_cluster(entry); 2526c4f9c701SHuang Ying } 2527c4f9c701SHuang Ying 25288cce5475SKirill A. Shutemov for (i = 0; i < nr; i++) { 2529e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2530e9b61f19SKirill A. Shutemov if (subpage == page) 2531e9b61f19SKirill A. Shutemov continue; 2532e9b61f19SKirill A. Shutemov unlock_page(subpage); 2533e9b61f19SKirill A. Shutemov 2534e9b61f19SKirill A. Shutemov /* 2535e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2536e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2537e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2538e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2539e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2540e9b61f19SKirill A. Shutemov */ 2541*0b175468SMiaohe Lin free_page_and_swap_cache(subpage); 2542e9b61f19SKirill A. Shutemov } 2543e9b61f19SKirill A. Shutemov } 2544e9b61f19SKirill A. Shutemov 2545b8f593cdSHuang Ying /* Racy check whether the huge page can be split */ 2546d4b4084aSMatthew Wilcox (Oracle) bool can_split_folio(struct folio *folio, int *pextra_pins) 2547b8f593cdSHuang Ying { 2548b8f593cdSHuang Ying int extra_pins; 2549b8f593cdSHuang Ying 2550aa5dc07fSMatthew Wilcox /* Additional pins from page cache */ 2551d4b4084aSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 2552d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_test_swapcache(folio) ? 2553d4b4084aSMatthew Wilcox (Oracle) folio_nr_pages(folio) : 0; 2554b8f593cdSHuang Ying else 2555d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_nr_pages(folio); 2556b8f593cdSHuang Ying if (pextra_pins) 2557b8f593cdSHuang Ying *pextra_pins = extra_pins; 2558d4b4084aSMatthew Wilcox (Oracle) return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; 2559b8f593cdSHuang Ying } 2560b8f593cdSHuang Ying 25616d0a07edSAndrea Arcangeli /* 2562e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2563e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2564e9b61f19SKirill A. Shutemov * 2565e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2566e9b61f19SKirill A. Shutemov * The huge page must be locked. 2567e9b61f19SKirill A. Shutemov * 2568e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2569e9b61f19SKirill A. Shutemov * 2570e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2571e9b61f19SKirill A. Shutemov * the hugepage. 2572e9b61f19SKirill A. Shutemov * 2573e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2574e9b61f19SKirill A. Shutemov * they are not mapped. 2575e9b61f19SKirill A. Shutemov * 2576e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2577e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2578e9b61f19SKirill A. Shutemov * us. 2579e9b61f19SKirill A. Shutemov */ 2580e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2581e9b61f19SKirill A. Shutemov { 25824eecb8b9SMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 25834eecb8b9SMatthew Wilcox (Oracle) struct page *head = &folio->page; 2584a8803e6cSWei Yang struct deferred_split *ds_queue = get_deferred_split_queue(head); 25856b24ca4aSMatthew Wilcox (Oracle) XA_STATE(xas, &head->mapping->i_pages, head->index); 2586baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2587baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2588504e070dSYang Shi int extra_pins, ret; 2589006d3ff2SHugh Dickins pgoff_t end; 2590478d134eSXu Yu bool is_hzp; 2591e9b61f19SKirill A. Shutemov 2592a8803e6cSWei Yang VM_BUG_ON_PAGE(!PageLocked(head), head); 2593a8803e6cSWei Yang VM_BUG_ON_PAGE(!PageCompound(head), head); 2594e9b61f19SKirill A. Shutemov 2595478d134eSXu Yu is_hzp = is_huge_zero_page(head); 2596478d134eSXu Yu VM_WARN_ON_ONCE_PAGE(is_hzp, head); 2597478d134eSXu Yu if (is_hzp) 2598478d134eSXu Yu return -EBUSY; 2599478d134eSXu Yu 2600a8803e6cSWei Yang if (PageWriteback(head)) 260159807685SHuang Ying return -EBUSY; 260259807685SHuang Ying 2603baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2604e9b61f19SKirill A. Shutemov /* 2605c1e8d7c6SMichel Lespinasse * The caller does not necessarily hold an mmap_lock that would 2606baa355fdSKirill A. Shutemov * prevent the anon_vma disappearing so we first we take a 2607baa355fdSKirill A. Shutemov * reference to it and then lock the anon_vma for write. This 26082f031c6fSMatthew Wilcox (Oracle) * is similar to folio_lock_anon_vma_read except the write lock 2609baa355fdSKirill A. Shutemov * is taken to serialise against parallel split or collapse 2610baa355fdSKirill A. Shutemov * operations. 2611e9b61f19SKirill A. Shutemov */ 2612e9b61f19SKirill A. Shutemov anon_vma = page_get_anon_vma(head); 2613e9b61f19SKirill A. Shutemov if (!anon_vma) { 2614e9b61f19SKirill A. Shutemov ret = -EBUSY; 2615e9b61f19SKirill A. Shutemov goto out; 2616e9b61f19SKirill A. Shutemov } 2617006d3ff2SHugh Dickins end = -1; 2618baa355fdSKirill A. Shutemov mapping = NULL; 2619e9b61f19SKirill A. Shutemov anon_vma_lock_write(anon_vma); 2620baa355fdSKirill A. Shutemov } else { 2621baa355fdSKirill A. Shutemov mapping = head->mapping; 2622baa355fdSKirill A. Shutemov 2623baa355fdSKirill A. Shutemov /* Truncated ? */ 2624baa355fdSKirill A. Shutemov if (!mapping) { 2625baa355fdSKirill A. Shutemov ret = -EBUSY; 2626baa355fdSKirill A. Shutemov goto out; 2627baa355fdSKirill A. Shutemov } 2628baa355fdSKirill A. Shutemov 26296b24ca4aSMatthew Wilcox (Oracle) xas_split_alloc(&xas, head, compound_order(head), 26306b24ca4aSMatthew Wilcox (Oracle) mapping_gfp_mask(mapping) & GFP_RECLAIM_MASK); 26316b24ca4aSMatthew Wilcox (Oracle) if (xas_error(&xas)) { 26326b24ca4aSMatthew Wilcox (Oracle) ret = xas_error(&xas); 26336b24ca4aSMatthew Wilcox (Oracle) goto out; 26346b24ca4aSMatthew Wilcox (Oracle) } 26356b24ca4aSMatthew Wilcox (Oracle) 2636baa355fdSKirill A. Shutemov anon_vma = NULL; 2637baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 2638006d3ff2SHugh Dickins 2639006d3ff2SHugh Dickins /* 2640006d3ff2SHugh Dickins *__split_huge_page() may need to trim off pages beyond EOF: 2641006d3ff2SHugh Dickins * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, 2642006d3ff2SHugh Dickins * which cannot be nested inside the page tree lock. So note 2643006d3ff2SHugh Dickins * end now: i_size itself may be changed at any moment, but 2644006d3ff2SHugh Dickins * head page lock is good enough to serialize the trimming. 2645006d3ff2SHugh Dickins */ 2646006d3ff2SHugh Dickins end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); 2647d144bf62SHugh Dickins if (shmem_mapping(mapping)) 2648d144bf62SHugh Dickins end = shmem_fallocend(mapping->host, end); 2649baa355fdSKirill A. Shutemov } 2650e9b61f19SKirill A. Shutemov 2651e9b61f19SKirill A. Shutemov /* 2652906f9cdfSHugh Dickins * Racy check if we can split the page, before unmap_page() will 2653e9b61f19SKirill A. Shutemov * split PMDs 2654e9b61f19SKirill A. Shutemov */ 2655d4b4084aSMatthew Wilcox (Oracle) if (!can_split_folio(folio, &extra_pins)) { 2656e9b61f19SKirill A. Shutemov ret = -EBUSY; 2657e9b61f19SKirill A. Shutemov goto out_unlock; 2658e9b61f19SKirill A. Shutemov } 2659e9b61f19SKirill A. Shutemov 2660906f9cdfSHugh Dickins unmap_page(head); 2661e9b61f19SKirill A. Shutemov 2662b6769834SAlex Shi /* block interrupt reentry in xa_lock and spinlock */ 2663b6769834SAlex Shi local_irq_disable(); 2664baa355fdSKirill A. Shutemov if (mapping) { 2665baa355fdSKirill A. Shutemov /* 2666aa5dc07fSMatthew Wilcox * Check if the head page is present in page cache. 2667baa355fdSKirill A. Shutemov * We assume all tail are present too, if head is there. 2668baa355fdSKirill A. Shutemov */ 26696b24ca4aSMatthew Wilcox (Oracle) xas_lock(&xas); 26706b24ca4aSMatthew Wilcox (Oracle) xas_reset(&xas); 2671aa5dc07fSMatthew Wilcox if (xas_load(&xas) != head) 2672baa355fdSKirill A. Shutemov goto fail; 2673baa355fdSKirill A. Shutemov } 2674baa355fdSKirill A. Shutemov 26750139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 2676364c1eebSYang Shi spin_lock(&ds_queue->split_queue_lock); 2677504e070dSYang Shi if (page_ref_freeze(head, 1 + extra_pins)) { 26789a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(head))) { 2679364c1eebSYang Shi ds_queue->split_queue_len--; 26809a982250SKirill A. Shutemov list_del(page_deferred_list(head)); 26819a982250SKirill A. Shutemov } 2682afb97172SWei Yang spin_unlock(&ds_queue->split_queue_lock); 268306d3eff6SKirill A. Shutemov if (mapping) { 2684bf9eceadSMuchun Song int nr = thp_nr_pages(head); 2685bf9eceadSMuchun Song 26866b24ca4aSMatthew Wilcox (Oracle) xas_split(&xas, head, thp_order(head)); 26871ca7554dSMarek Szyprowski if (PageSwapBacked(head)) { 268857b2847dSMuchun Song __mod_lruvec_page_state(head, NR_SHMEM_THPS, 268957b2847dSMuchun Song -nr); 26901ca7554dSMarek Szyprowski } else { 2691bf9eceadSMuchun Song __mod_lruvec_page_state(head, NR_FILE_THPS, 2692bf9eceadSMuchun Song -nr); 26931ca7554dSMarek Szyprowski filemap_nr_thps_dec(mapping); 26941ca7554dSMarek Szyprowski } 269506d3eff6SKirill A. Shutemov } 269606d3eff6SKirill A. Shutemov 2697b6769834SAlex Shi __split_huge_page(page, list, end); 2698e9b61f19SKirill A. Shutemov ret = 0; 2699baa355fdSKirill A. Shutemov } else { 2700364c1eebSYang Shi spin_unlock(&ds_queue->split_queue_lock); 2701504e070dSYang Shi fail: 2702504e070dSYang Shi if (mapping) 27036b24ca4aSMatthew Wilcox (Oracle) xas_unlock(&xas); 2704b6769834SAlex Shi local_irq_enable(); 27054eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, folio_nr_pages(folio)); 2706e9b61f19SKirill A. Shutemov ret = -EBUSY; 2707e9b61f19SKirill A. Shutemov } 2708e9b61f19SKirill A. Shutemov 2709e9b61f19SKirill A. Shutemov out_unlock: 2710baa355fdSKirill A. Shutemov if (anon_vma) { 2711e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 2712e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 2713baa355fdSKirill A. Shutemov } 2714baa355fdSKirill A. Shutemov if (mapping) 2715baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 2716e9b61f19SKirill A. Shutemov out: 271769a37a8bSMatthew Wilcox (Oracle) xas_destroy(&xas); 2718e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 2719e9b61f19SKirill A. Shutemov return ret; 2720e9b61f19SKirill A. Shutemov } 27219a982250SKirill A. Shutemov 27229a982250SKirill A. Shutemov void free_transhuge_page(struct page *page) 27239a982250SKirill A. Shutemov { 272487eaceb3SYang Shi struct deferred_split *ds_queue = get_deferred_split_queue(page); 27259a982250SKirill A. Shutemov unsigned long flags; 27269a982250SKirill A. Shutemov 2727364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 27289a982250SKirill A. Shutemov if (!list_empty(page_deferred_list(page))) { 2729364c1eebSYang Shi ds_queue->split_queue_len--; 27309a982250SKirill A. Shutemov list_del(page_deferred_list(page)); 27319a982250SKirill A. Shutemov } 2732364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 27339a982250SKirill A. Shutemov free_compound_page(page); 27349a982250SKirill A. Shutemov } 27359a982250SKirill A. Shutemov 27369a982250SKirill A. Shutemov void deferred_split_huge_page(struct page *page) 27379a982250SKirill A. Shutemov { 273887eaceb3SYang Shi struct deferred_split *ds_queue = get_deferred_split_queue(page); 273987eaceb3SYang Shi #ifdef CONFIG_MEMCG 2740bcfe06bfSRoman Gushchin struct mem_cgroup *memcg = page_memcg(compound_head(page)); 274187eaceb3SYang Shi #endif 27429a982250SKirill A. Shutemov unsigned long flags; 27439a982250SKirill A. Shutemov 27449a982250SKirill A. Shutemov VM_BUG_ON_PAGE(!PageTransHuge(page), page); 27459a982250SKirill A. Shutemov 274687eaceb3SYang Shi /* 274787eaceb3SYang Shi * The try_to_unmap() in page reclaim path might reach here too, 274887eaceb3SYang Shi * this may cause a race condition to corrupt deferred split queue. 274987eaceb3SYang Shi * And, if page reclaim is already handling the same page, it is 275087eaceb3SYang Shi * unnecessary to handle it again in shrinker. 275187eaceb3SYang Shi * 275287eaceb3SYang Shi * Check PageSwapCache to determine if the page is being 275387eaceb3SYang Shi * handled by page reclaim since THP swap would add the page into 275487eaceb3SYang Shi * swap cache before calling try_to_unmap(). 275587eaceb3SYang Shi */ 275687eaceb3SYang Shi if (PageSwapCache(page)) 275787eaceb3SYang Shi return; 275887eaceb3SYang Shi 2759364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 27609a982250SKirill A. Shutemov if (list_empty(page_deferred_list(page))) { 2761f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 2762364c1eebSYang Shi list_add_tail(page_deferred_list(page), &ds_queue->split_queue); 2763364c1eebSYang Shi ds_queue->split_queue_len++; 276487eaceb3SYang Shi #ifdef CONFIG_MEMCG 276587eaceb3SYang Shi if (memcg) 27662bfd3637SYang Shi set_shrinker_bit(memcg, page_to_nid(page), 276787eaceb3SYang Shi deferred_split_shrinker.id); 276887eaceb3SYang Shi #endif 27699a982250SKirill A. Shutemov } 2770364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 27719a982250SKirill A. Shutemov } 27729a982250SKirill A. Shutemov 27739a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 27749a982250SKirill A. Shutemov struct shrink_control *sc) 27759a982250SKirill A. Shutemov { 2776a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2777364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 277887eaceb3SYang Shi 277987eaceb3SYang Shi #ifdef CONFIG_MEMCG 278087eaceb3SYang Shi if (sc->memcg) 278187eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 278287eaceb3SYang Shi #endif 2783364c1eebSYang Shi return READ_ONCE(ds_queue->split_queue_len); 27849a982250SKirill A. Shutemov } 27859a982250SKirill A. Shutemov 27869a982250SKirill A. Shutemov static unsigned long deferred_split_scan(struct shrinker *shrink, 27879a982250SKirill A. Shutemov struct shrink_control *sc) 27889a982250SKirill A. Shutemov { 2789a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 2790364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 27919a982250SKirill A. Shutemov unsigned long flags; 27929a982250SKirill A. Shutemov LIST_HEAD(list), *pos, *next; 27939a982250SKirill A. Shutemov struct page *page; 27949a982250SKirill A. Shutemov int split = 0; 27959a982250SKirill A. Shutemov 279687eaceb3SYang Shi #ifdef CONFIG_MEMCG 279787eaceb3SYang Shi if (sc->memcg) 279887eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 279987eaceb3SYang Shi #endif 280087eaceb3SYang Shi 2801364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 28029a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 2803364c1eebSYang Shi list_for_each_safe(pos, next, &ds_queue->split_queue) { 2804dfe5c51cSMiaohe Lin page = list_entry((void *)pos, struct page, deferred_list); 28059a982250SKirill A. Shutemov page = compound_head(page); 2806e3ae1953SKirill A. Shutemov if (get_page_unless_zero(page)) { 2807e3ae1953SKirill A. Shutemov list_move(page_deferred_list(page), &list); 2808e3ae1953SKirill A. Shutemov } else { 2809e3ae1953SKirill A. Shutemov /* We lost race with put_compound_page() */ 28109a982250SKirill A. Shutemov list_del_init(page_deferred_list(page)); 2811364c1eebSYang Shi ds_queue->split_queue_len--; 28129a982250SKirill A. Shutemov } 2813e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 2814e3ae1953SKirill A. Shutemov break; 28159a982250SKirill A. Shutemov } 2816364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28179a982250SKirill A. Shutemov 28189a982250SKirill A. Shutemov list_for_each_safe(pos, next, &list) { 2819dfe5c51cSMiaohe Lin page = list_entry((void *)pos, struct page, deferred_list); 2820fa41b900SKirill A. Shutemov if (!trylock_page(page)) 2821fa41b900SKirill A. Shutemov goto next; 28229a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 28239a982250SKirill A. Shutemov if (!split_huge_page(page)) 28249a982250SKirill A. Shutemov split++; 28259a982250SKirill A. Shutemov unlock_page(page); 2826fa41b900SKirill A. Shutemov next: 28279a982250SKirill A. Shutemov put_page(page); 28289a982250SKirill A. Shutemov } 28299a982250SKirill A. Shutemov 2830364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 2831364c1eebSYang Shi list_splice_tail(&list, &ds_queue->split_queue); 2832364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 28339a982250SKirill A. Shutemov 2834cb8d68ecSKirill A. Shutemov /* 2835cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 2836cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 2837cb8d68ecSKirill A. Shutemov */ 2838364c1eebSYang Shi if (!split && list_empty(&ds_queue->split_queue)) 2839cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 2840cb8d68ecSKirill A. Shutemov return split; 28419a982250SKirill A. Shutemov } 28429a982250SKirill A. Shutemov 28439a982250SKirill A. Shutemov static struct shrinker deferred_split_shrinker = { 28449a982250SKirill A. Shutemov .count_objects = deferred_split_count, 28459a982250SKirill A. Shutemov .scan_objects = deferred_split_scan, 28469a982250SKirill A. Shutemov .seeks = DEFAULT_SEEKS, 284787eaceb3SYang Shi .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | 284887eaceb3SYang Shi SHRINKER_NONSLAB, 28499a982250SKirill A. Shutemov }; 285049071d43SKirill A. Shutemov 285149071d43SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 2852fa6c0231SZi Yan static void split_huge_pages_all(void) 285349071d43SKirill A. Shutemov { 285449071d43SKirill A. Shutemov struct zone *zone; 285549071d43SKirill A. Shutemov struct page *page; 285649071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 285749071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 285849071d43SKirill A. Shutemov 2859fa6c0231SZi Yan pr_debug("Split all THPs\n"); 286049071d43SKirill A. Shutemov for_each_populated_zone(zone) { 286149071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 286249071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 286349071d43SKirill A. Shutemov if (!pfn_valid(pfn)) 286449071d43SKirill A. Shutemov continue; 286549071d43SKirill A. Shutemov 286649071d43SKirill A. Shutemov page = pfn_to_page(pfn); 286749071d43SKirill A. Shutemov if (!get_page_unless_zero(page)) 286849071d43SKirill A. Shutemov continue; 286949071d43SKirill A. Shutemov 287049071d43SKirill A. Shutemov if (zone != page_zone(page)) 287149071d43SKirill A. Shutemov goto next; 287249071d43SKirill A. Shutemov 2873baa355fdSKirill A. Shutemov if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) 287449071d43SKirill A. Shutemov goto next; 287549071d43SKirill A. Shutemov 287649071d43SKirill A. Shutemov total++; 287749071d43SKirill A. Shutemov lock_page(page); 287849071d43SKirill A. Shutemov if (!split_huge_page(page)) 287949071d43SKirill A. Shutemov split++; 288049071d43SKirill A. Shutemov unlock_page(page); 288149071d43SKirill A. Shutemov next: 288249071d43SKirill A. Shutemov put_page(page); 2883fa6c0231SZi Yan cond_resched(); 288449071d43SKirill A. Shutemov } 288549071d43SKirill A. Shutemov } 288649071d43SKirill A. Shutemov 2887fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 288849071d43SKirill A. Shutemov } 2889fa6c0231SZi Yan 2890fa6c0231SZi Yan static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) 2891fa6c0231SZi Yan { 2892fa6c0231SZi Yan return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || 2893fa6c0231SZi Yan is_vm_hugetlb_page(vma); 2894fa6c0231SZi Yan } 2895fa6c0231SZi Yan 2896fa6c0231SZi Yan static int split_huge_pages_pid(int pid, unsigned long vaddr_start, 2897fa6c0231SZi Yan unsigned long vaddr_end) 2898fa6c0231SZi Yan { 2899fa6c0231SZi Yan int ret = 0; 2900fa6c0231SZi Yan struct task_struct *task; 2901fa6c0231SZi Yan struct mm_struct *mm; 2902fa6c0231SZi Yan unsigned long total = 0, split = 0; 2903fa6c0231SZi Yan unsigned long addr; 2904fa6c0231SZi Yan 2905fa6c0231SZi Yan vaddr_start &= PAGE_MASK; 2906fa6c0231SZi Yan vaddr_end &= PAGE_MASK; 2907fa6c0231SZi Yan 2908fa6c0231SZi Yan /* Find the task_struct from pid */ 2909fa6c0231SZi Yan rcu_read_lock(); 2910fa6c0231SZi Yan task = find_task_by_vpid(pid); 2911fa6c0231SZi Yan if (!task) { 2912fa6c0231SZi Yan rcu_read_unlock(); 2913fa6c0231SZi Yan ret = -ESRCH; 2914fa6c0231SZi Yan goto out; 2915fa6c0231SZi Yan } 2916fa6c0231SZi Yan get_task_struct(task); 2917fa6c0231SZi Yan rcu_read_unlock(); 2918fa6c0231SZi Yan 2919fa6c0231SZi Yan /* Find the mm_struct */ 2920fa6c0231SZi Yan mm = get_task_mm(task); 2921fa6c0231SZi Yan put_task_struct(task); 2922fa6c0231SZi Yan 2923fa6c0231SZi Yan if (!mm) { 2924fa6c0231SZi Yan ret = -EINVAL; 2925fa6c0231SZi Yan goto out; 2926fa6c0231SZi Yan } 2927fa6c0231SZi Yan 2928fa6c0231SZi Yan pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", 2929fa6c0231SZi Yan pid, vaddr_start, vaddr_end); 2930fa6c0231SZi Yan 2931fa6c0231SZi Yan mmap_read_lock(mm); 2932fa6c0231SZi Yan /* 2933fa6c0231SZi Yan * always increase addr by PAGE_SIZE, since we could have a PTE page 2934fa6c0231SZi Yan * table filled with PTE-mapped THPs, each of which is distinct. 2935fa6c0231SZi Yan */ 2936fa6c0231SZi Yan for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { 293774ba2b38SMiaohe Lin struct vm_area_struct *vma = vma_lookup(mm, addr); 2938fa6c0231SZi Yan struct page *page; 2939fa6c0231SZi Yan 294074ba2b38SMiaohe Lin if (!vma) 2941fa6c0231SZi Yan break; 2942fa6c0231SZi Yan 2943fa6c0231SZi Yan /* skip special VMA and hugetlb VMA */ 2944fa6c0231SZi Yan if (vma_not_suitable_for_thp_split(vma)) { 2945fa6c0231SZi Yan addr = vma->vm_end; 2946fa6c0231SZi Yan continue; 2947fa6c0231SZi Yan } 2948fa6c0231SZi Yan 2949fa6c0231SZi Yan /* FOLL_DUMP to ignore special (like zero) pages */ 295087d2762eSMiaohe Lin page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); 2951fa6c0231SZi Yan 2952fa6c0231SZi Yan if (IS_ERR(page)) 2953fa6c0231SZi Yan continue; 29543218f871SAlex Sierra if (!page || is_zone_device_page(page)) 2955fa6c0231SZi Yan continue; 2956fa6c0231SZi Yan 2957fa6c0231SZi Yan if (!is_transparent_hugepage(page)) 2958fa6c0231SZi Yan goto next; 2959fa6c0231SZi Yan 2960fa6c0231SZi Yan total++; 2961d4b4084aSMatthew Wilcox (Oracle) if (!can_split_folio(page_folio(page), NULL)) 2962fa6c0231SZi Yan goto next; 2963fa6c0231SZi Yan 2964fa6c0231SZi Yan if (!trylock_page(page)) 2965fa6c0231SZi Yan goto next; 2966fa6c0231SZi Yan 2967fa6c0231SZi Yan if (!split_huge_page(page)) 2968fa6c0231SZi Yan split++; 2969fa6c0231SZi Yan 2970fa6c0231SZi Yan unlock_page(page); 2971fa6c0231SZi Yan next: 2972fa6c0231SZi Yan put_page(page); 2973fa6c0231SZi Yan cond_resched(); 2974fa6c0231SZi Yan } 2975fa6c0231SZi Yan mmap_read_unlock(mm); 2976fa6c0231SZi Yan mmput(mm); 2977fa6c0231SZi Yan 2978fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 2979fa6c0231SZi Yan 2980fa6c0231SZi Yan out: 2981fa6c0231SZi Yan return ret; 2982fa6c0231SZi Yan } 2983fa6c0231SZi Yan 2984fbe37501SZi Yan static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, 2985fbe37501SZi Yan pgoff_t off_end) 2986fbe37501SZi Yan { 2987fbe37501SZi Yan struct filename *file; 2988fbe37501SZi Yan struct file *candidate; 2989fbe37501SZi Yan struct address_space *mapping; 2990fbe37501SZi Yan int ret = -EINVAL; 2991fbe37501SZi Yan pgoff_t index; 2992fbe37501SZi Yan int nr_pages = 1; 2993fbe37501SZi Yan unsigned long total = 0, split = 0; 2994fbe37501SZi Yan 2995fbe37501SZi Yan file = getname_kernel(file_path); 2996fbe37501SZi Yan if (IS_ERR(file)) 2997fbe37501SZi Yan return ret; 2998fbe37501SZi Yan 2999fbe37501SZi Yan candidate = file_open_name(file, O_RDONLY, 0); 3000fbe37501SZi Yan if (IS_ERR(candidate)) 3001fbe37501SZi Yan goto out; 3002fbe37501SZi Yan 3003fbe37501SZi Yan pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", 3004fbe37501SZi Yan file_path, off_start, off_end); 3005fbe37501SZi Yan 3006fbe37501SZi Yan mapping = candidate->f_mapping; 3007fbe37501SZi Yan 3008fbe37501SZi Yan for (index = off_start; index < off_end; index += nr_pages) { 3009fbe37501SZi Yan struct page *fpage = pagecache_get_page(mapping, index, 3010fbe37501SZi Yan FGP_ENTRY | FGP_HEAD, 0); 3011fbe37501SZi Yan 3012fbe37501SZi Yan nr_pages = 1; 3013fbe37501SZi Yan if (xa_is_value(fpage) || !fpage) 3014fbe37501SZi Yan continue; 3015fbe37501SZi Yan 3016fbe37501SZi Yan if (!is_transparent_hugepage(fpage)) 3017fbe37501SZi Yan goto next; 3018fbe37501SZi Yan 3019fbe37501SZi Yan total++; 3020fbe37501SZi Yan nr_pages = thp_nr_pages(fpage); 3021fbe37501SZi Yan 3022fbe37501SZi Yan if (!trylock_page(fpage)) 3023fbe37501SZi Yan goto next; 3024fbe37501SZi Yan 3025fbe37501SZi Yan if (!split_huge_page(fpage)) 3026fbe37501SZi Yan split++; 3027fbe37501SZi Yan 3028fbe37501SZi Yan unlock_page(fpage); 3029fbe37501SZi Yan next: 3030fbe37501SZi Yan put_page(fpage); 3031fbe37501SZi Yan cond_resched(); 3032fbe37501SZi Yan } 3033fbe37501SZi Yan 3034fbe37501SZi Yan filp_close(candidate, NULL); 3035fbe37501SZi Yan ret = 0; 3036fbe37501SZi Yan 3037fbe37501SZi Yan pr_debug("%lu of %lu file-backed THP split\n", split, total); 3038fbe37501SZi Yan out: 3039fbe37501SZi Yan putname(file); 3040fbe37501SZi Yan return ret; 3041fbe37501SZi Yan } 3042fbe37501SZi Yan 3043fa6c0231SZi Yan #define MAX_INPUT_BUF_SZ 255 3044fa6c0231SZi Yan 3045fa6c0231SZi Yan static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, 3046fa6c0231SZi Yan size_t count, loff_t *ppops) 3047fa6c0231SZi Yan { 3048fa6c0231SZi Yan static DEFINE_MUTEX(split_debug_mutex); 3049fa6c0231SZi Yan ssize_t ret; 3050fbe37501SZi Yan /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ 3051fbe37501SZi Yan char input_buf[MAX_INPUT_BUF_SZ]; 3052fa6c0231SZi Yan int pid; 3053fa6c0231SZi Yan unsigned long vaddr_start, vaddr_end; 3054fa6c0231SZi Yan 3055fa6c0231SZi Yan ret = mutex_lock_interruptible(&split_debug_mutex); 3056fa6c0231SZi Yan if (ret) 3057fa6c0231SZi Yan return ret; 3058fa6c0231SZi Yan 3059fa6c0231SZi Yan ret = -EFAULT; 3060fa6c0231SZi Yan 3061fa6c0231SZi Yan memset(input_buf, 0, MAX_INPUT_BUF_SZ); 3062fa6c0231SZi Yan if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) 3063fa6c0231SZi Yan goto out; 3064fa6c0231SZi Yan 3065fa6c0231SZi Yan input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; 3066fbe37501SZi Yan 3067fbe37501SZi Yan if (input_buf[0] == '/') { 3068fbe37501SZi Yan char *tok; 3069fbe37501SZi Yan char *buf = input_buf; 3070fbe37501SZi Yan char file_path[MAX_INPUT_BUF_SZ]; 3071fbe37501SZi Yan pgoff_t off_start = 0, off_end = 0; 3072fbe37501SZi Yan size_t input_len = strlen(input_buf); 3073fbe37501SZi Yan 3074fbe37501SZi Yan tok = strsep(&buf, ","); 3075fbe37501SZi Yan if (tok) { 30761212e00cSMatthew Wilcox (Oracle) strcpy(file_path, tok); 3077fbe37501SZi Yan } else { 3078fbe37501SZi Yan ret = -EINVAL; 3079fbe37501SZi Yan goto out; 3080fbe37501SZi Yan } 3081fbe37501SZi Yan 3082fbe37501SZi Yan ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); 3083fbe37501SZi Yan if (ret != 2) { 3084fbe37501SZi Yan ret = -EINVAL; 3085fbe37501SZi Yan goto out; 3086fbe37501SZi Yan } 3087fbe37501SZi Yan ret = split_huge_pages_in_file(file_path, off_start, off_end); 3088fbe37501SZi Yan if (!ret) 3089fbe37501SZi Yan ret = input_len; 3090fbe37501SZi Yan 3091fbe37501SZi Yan goto out; 3092fbe37501SZi Yan } 3093fbe37501SZi Yan 3094fa6c0231SZi Yan ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); 3095fa6c0231SZi Yan if (ret == 1 && pid == 1) { 3096fa6c0231SZi Yan split_huge_pages_all(); 3097fa6c0231SZi Yan ret = strlen(input_buf); 3098fa6c0231SZi Yan goto out; 3099fa6c0231SZi Yan } else if (ret != 3) { 3100fa6c0231SZi Yan ret = -EINVAL; 3101fa6c0231SZi Yan goto out; 3102fa6c0231SZi Yan } 3103fa6c0231SZi Yan 3104fa6c0231SZi Yan ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); 3105fa6c0231SZi Yan if (!ret) 3106fa6c0231SZi Yan ret = strlen(input_buf); 3107fa6c0231SZi Yan out: 3108fa6c0231SZi Yan mutex_unlock(&split_debug_mutex); 3109fa6c0231SZi Yan return ret; 3110fa6c0231SZi Yan 3111fa6c0231SZi Yan } 3112fa6c0231SZi Yan 3113fa6c0231SZi Yan static const struct file_operations split_huge_pages_fops = { 3114fa6c0231SZi Yan .owner = THIS_MODULE, 3115fa6c0231SZi Yan .write = split_huge_pages_write, 3116fa6c0231SZi Yan .llseek = no_llseek, 3117fa6c0231SZi Yan }; 311849071d43SKirill A. Shutemov 311949071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 312049071d43SKirill A. Shutemov { 3121d9f7979cSGreg Kroah-Hartman debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 312249071d43SKirill A. Shutemov &split_huge_pages_fops); 312349071d43SKirill A. Shutemov return 0; 312449071d43SKirill A. Shutemov } 312549071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 312649071d43SKirill A. Shutemov #endif 3127616b8371SZi Yan 3128616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 31297f5abe60SDavid Hildenbrand int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 3130616b8371SZi Yan struct page *page) 3131616b8371SZi Yan { 3132616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3133616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3134616b8371SZi Yan unsigned long address = pvmw->address; 31356c287605SDavid Hildenbrand bool anon_exclusive; 3136616b8371SZi Yan pmd_t pmdval; 3137616b8371SZi Yan swp_entry_t entry; 3138ab6e3d09SNaoya Horiguchi pmd_t pmdswp; 3139616b8371SZi Yan 3140616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 31417f5abe60SDavid Hildenbrand return 0; 3142616b8371SZi Yan 3143616b8371SZi Yan flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); 31448a8683adSHuang Ying pmdval = pmdp_invalidate(vma, address, pvmw->pmd); 31456c287605SDavid Hildenbrand 31466c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 31476c287605SDavid Hildenbrand if (anon_exclusive && page_try_share_anon_rmap(page)) { 31486c287605SDavid Hildenbrand set_pmd_at(mm, address, pvmw->pmd, pmdval); 31497f5abe60SDavid Hildenbrand return -EBUSY; 31506c287605SDavid Hildenbrand } 31516c287605SDavid Hildenbrand 3152616b8371SZi Yan if (pmd_dirty(pmdval)) 3153616b8371SZi Yan set_page_dirty(page); 31544dd845b5SAlistair Popple if (pmd_write(pmdval)) 31554dd845b5SAlistair Popple entry = make_writable_migration_entry(page_to_pfn(page)); 31566c287605SDavid Hildenbrand else if (anon_exclusive) 31576c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); 31584dd845b5SAlistair Popple else 31594dd845b5SAlistair Popple entry = make_readable_migration_entry(page_to_pfn(page)); 3160ab6e3d09SNaoya Horiguchi pmdswp = swp_entry_to_pmd(entry); 3161ab6e3d09SNaoya Horiguchi if (pmd_soft_dirty(pmdval)) 3162ab6e3d09SNaoya Horiguchi pmdswp = pmd_swp_mksoft_dirty(pmdswp); 3163ab6e3d09SNaoya Horiguchi set_pmd_at(mm, address, pvmw->pmd, pmdswp); 3164cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 3165616b8371SZi Yan put_page(page); 3166283fd6feSAnshuman Khandual trace_set_migration_pmd(address, pmd_val(pmdswp)); 31677f5abe60SDavid Hildenbrand 31687f5abe60SDavid Hildenbrand return 0; 3169616b8371SZi Yan } 3170616b8371SZi Yan 3171616b8371SZi Yan void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 3172616b8371SZi Yan { 3173616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3174616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3175616b8371SZi Yan unsigned long address = pvmw->address; 31764fba8f2aSMiaohe Lin unsigned long haddr = address & HPAGE_PMD_MASK; 3177616b8371SZi Yan pmd_t pmde; 3178616b8371SZi Yan swp_entry_t entry; 3179616b8371SZi Yan 3180616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 3181616b8371SZi Yan return; 3182616b8371SZi Yan 3183616b8371SZi Yan entry = pmd_to_swp_entry(*pvmw->pmd); 3184616b8371SZi Yan get_page(new); 31854286f147SMiaohe Lin pmde = pmd_mkold(mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot))); 3186ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pvmw->pmd)) 3187ab6e3d09SNaoya Horiguchi pmde = pmd_mksoft_dirty(pmde); 31884dd845b5SAlistair Popple if (is_writable_migration_entry(entry)) 3189f55e1014SLinus Torvalds pmde = maybe_pmd_mkwrite(pmde, vma); 31908f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*pvmw->pmd)) 31918f34f1eaSPeter Xu pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde)); 3192616b8371SZi Yan 31936c287605SDavid Hildenbrand if (PageAnon(new)) { 31946c287605SDavid Hildenbrand rmap_t rmap_flags = RMAP_COMPOUND; 31956c287605SDavid Hildenbrand 31966c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) 31976c287605SDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 31986c287605SDavid Hildenbrand 31994fba8f2aSMiaohe Lin page_add_anon_rmap(new, vma, haddr, rmap_flags); 32006c287605SDavid Hildenbrand } else { 3201cea86fe2SHugh Dickins page_add_file_rmap(new, vma, true); 32026c287605SDavid Hildenbrand } 32036c287605SDavid Hildenbrand VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); 32044fba8f2aSMiaohe Lin set_pmd_at(mm, haddr, pvmw->pmd, pmde); 32055cbcf225SMuchun Song 32065cbcf225SMuchun Song /* No need to invalidate - it was non-present before */ 3207616b8371SZi Yan update_mmu_cache_pmd(vma, address, pvmw->pmd); 3208283fd6feSAnshuman Khandual trace_remove_migration_pmd(address, pmd_val(pmde)); 3209616b8371SZi Yan } 3210616b8371SZi Yan #endif 3211