120c8ccb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 271e3aac0SAndrea Arcangeli /* 371e3aac0SAndrea Arcangeli * Copyright (C) 2009 Red Hat, Inc. 471e3aac0SAndrea Arcangeli */ 571e3aac0SAndrea Arcangeli 6ae3a8c1cSAndrew Morton #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 7ae3a8c1cSAndrew Morton 871e3aac0SAndrea Arcangeli #include <linux/mm.h> 971e3aac0SAndrea Arcangeli #include <linux/sched.h> 10fa6c0231SZi Yan #include <linux/sched/mm.h> 11f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 126a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 1371e3aac0SAndrea Arcangeli #include <linux/highmem.h> 1471e3aac0SAndrea Arcangeli #include <linux/hugetlb.h> 1571e3aac0SAndrea Arcangeli #include <linux/mmu_notifier.h> 1671e3aac0SAndrea Arcangeli #include <linux/rmap.h> 1771e3aac0SAndrea Arcangeli #include <linux/swap.h> 1897ae1749SKirill A. Shutemov #include <linux/shrinker.h> 19ba76149fSAndrea Arcangeli #include <linux/mm_inline.h> 20e9b61f19SKirill A. Shutemov #include <linux/swapops.h> 21fb5c2029SMatthew Wilcox (Oracle) #include <linux/backing-dev.h> 224897c765SMatthew Wilcox #include <linux/dax.h> 23ba76149fSAndrea Arcangeli #include <linux/khugepaged.h> 24878aee7dSAndrea Arcangeli #include <linux/freezer.h> 25f25748e3SDan Williams #include <linux/pfn_t.h> 26a664b2d8SAndrea Arcangeli #include <linux/mman.h> 273565fce3SDan Williams #include <linux/memremap.h> 28325adeb5SRalf Baechle #include <linux/pagemap.h> 2949071d43SKirill A. Shutemov #include <linux/debugfs.h> 304daae3b4SMel Gorman #include <linux/migrate.h> 3143b5fbbdSSasha Levin #include <linux/hashtable.h> 326b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 3333c3fc71SVladimir Davydov #include <linux/page_idle.h> 34baa355fdSKirill A. Shutemov #include <linux/shmem_fs.h> 356b31d595SMichal Hocko #include <linux/oom.h> 3698fa15f3SAnshuman Khandual #include <linux/numa.h> 37f7da677bSVlastimil Babka #include <linux/page_owner.h> 38a1a3a2fcSHuang Ying #include <linux/sched/sysctl.h> 39467b171aSAneesh Kumar K.V #include <linux/memory-tiers.h> 4097ae1749SKirill A. Shutemov 4171e3aac0SAndrea Arcangeli #include <asm/tlb.h> 4271e3aac0SAndrea Arcangeli #include <asm/pgalloc.h> 4371e3aac0SAndrea Arcangeli #include "internal.h" 44014bb1deSNeilBrown #include "swap.h" 4571e3aac0SAndrea Arcangeli 46283fd6feSAnshuman Khandual #define CREATE_TRACE_POINTS 47283fd6feSAnshuman Khandual #include <trace/events/thp.h> 48283fd6feSAnshuman Khandual 49ba76149fSAndrea Arcangeli /* 50b14d595aSMichael DeGuzis * By default, transparent hugepage support is disabled in order to avoid 51b14d595aSMichael DeGuzis * risking an increased memory footprint for applications that are not 52b14d595aSMichael DeGuzis * guaranteed to benefit from it. When transparent hugepage support is 53b14d595aSMichael DeGuzis * enabled, it is for all mappings, and khugepaged scans all mappings. 548bfa3f9aSJianguo Wu * Defrag is invoked by khugepaged hugepage allocations and by page faults 558bfa3f9aSJianguo Wu * for all hugepage allocations. 56ba76149fSAndrea Arcangeli */ 5771e3aac0SAndrea Arcangeli unsigned long transparent_hugepage_flags __read_mostly = 5813ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS 59ba76149fSAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_FLAG)| 6013ece886SAndrea Arcangeli #endif 6113ece886SAndrea Arcangeli #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE 6213ece886SAndrea Arcangeli (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| 6313ece886SAndrea Arcangeli #endif 64444eb2a4SMel Gorman (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| 6579da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| 6679da5407SKirill A. Shutemov (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 67ba76149fSAndrea Arcangeli 6854d91729SQi Zheng static struct shrinker *deferred_split_shrinker; 6954d91729SQi Zheng static unsigned long deferred_split_count(struct shrinker *shrink, 7054d91729SQi Zheng struct shrink_control *sc); 7154d91729SQi Zheng static unsigned long deferred_split_scan(struct shrinker *shrink, 7254d91729SQi Zheng struct shrink_control *sc); 73f000565aSAndrea Arcangeli 7497ae1749SKirill A. Shutemov static atomic_t huge_zero_refcount; 7556873f43SWang, Yalin struct page *huge_zero_page __read_mostly; 763b77e8c8SHugh Dickins unsigned long huge_zero_pfn __read_mostly = ~0UL; 773485b883SRyan Roberts unsigned long huge_anon_orders_always __read_mostly; 783485b883SRyan Roberts unsigned long huge_anon_orders_madvise __read_mostly; 793485b883SRyan Roberts unsigned long huge_anon_orders_inherit __read_mostly; 804a6c1297SKirill A. Shutemov 813485b883SRyan Roberts unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma, 823485b883SRyan Roberts unsigned long vm_flags, bool smaps, 833485b883SRyan Roberts bool in_pf, bool enforce_sysfs, 843485b883SRyan Roberts unsigned long orders) 857635d9cbSMichal Hocko { 863485b883SRyan Roberts /* Check the intersection of requested and supported orders. */ 873485b883SRyan Roberts orders &= vma_is_anonymous(vma) ? 883485b883SRyan Roberts THP_ORDERS_ALL_ANON : THP_ORDERS_ALL_FILE; 893485b883SRyan Roberts if (!orders) 903485b883SRyan Roberts return 0; 913485b883SRyan Roberts 929fec5168SYang Shi if (!vma->vm_mm) /* vdso */ 933485b883SRyan Roberts return 0; 949fec5168SYang Shi 957da4e2cbSYang Shi /* 967da4e2cbSYang Shi * Explicitly disabled through madvise or prctl, or some 977da4e2cbSYang Shi * architectures may disable THP for some mappings, for 987da4e2cbSYang Shi * example, s390 kvm. 997da4e2cbSYang Shi * */ 1007da4e2cbSYang Shi if ((vm_flags & VM_NOHUGEPAGE) || 1017da4e2cbSYang Shi test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) 1023485b883SRyan Roberts return 0; 1037da4e2cbSYang Shi /* 1047da4e2cbSYang Shi * If the hardware/firmware marked hugepage support disabled. 1057da4e2cbSYang Shi */ 1063c556d24SPeter Xu if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED)) 1073485b883SRyan Roberts return 0; 1089fec5168SYang Shi 1097da4e2cbSYang Shi /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ 1107da4e2cbSYang Shi if (vma_is_dax(vma)) 1113485b883SRyan Roberts return in_pf ? orders : 0; 1127da4e2cbSYang Shi 1137da4e2cbSYang Shi /* 1147a81751fSZach O'Keefe * khugepaged special VMA and hugetlb VMA. 1157da4e2cbSYang Shi * Must be checked after dax since some dax mappings may have 1167da4e2cbSYang Shi * VM_MIXEDMAP set. 1177da4e2cbSYang Shi */ 1187a81751fSZach O'Keefe if (!in_pf && !smaps && (vm_flags & VM_NO_KHUGEPAGED)) 1193485b883SRyan Roberts return 0; 1209fec5168SYang Shi 1217da4e2cbSYang Shi /* 1223485b883SRyan Roberts * Check alignment for file vma and size for both file and anon vma by 1233485b883SRyan Roberts * filtering out the unsuitable orders. 1247da4e2cbSYang Shi * 1257da4e2cbSYang Shi * Skip the check for page fault. Huge fault does the check in fault 1263485b883SRyan Roberts * handlers. 1277da4e2cbSYang Shi */ 1283485b883SRyan Roberts if (!in_pf) { 1293485b883SRyan Roberts int order = highest_order(orders); 1303485b883SRyan Roberts unsigned long addr; 1313485b883SRyan Roberts 1323485b883SRyan Roberts while (orders) { 1333485b883SRyan Roberts addr = vma->vm_end - (PAGE_SIZE << order); 1343485b883SRyan Roberts if (thp_vma_suitable_order(vma, addr, order)) 1353485b883SRyan Roberts break; 1363485b883SRyan Roberts order = next_order(&orders, order); 1373485b883SRyan Roberts } 1383485b883SRyan Roberts 1393485b883SRyan Roberts if (!orders) 1403485b883SRyan Roberts return 0; 1413485b883SRyan Roberts } 1429fec5168SYang Shi 1437da4e2cbSYang Shi /* 1447da4e2cbSYang Shi * Enabled via shmem mount options or sysfs settings. 1457da4e2cbSYang Shi * Must be done before hugepage flags check since shmem has its 1467da4e2cbSYang Shi * own flags. 1477da4e2cbSYang Shi */ 1487da4e2cbSYang Shi if (!in_pf && shmem_file(vma->vm_file)) 1492cf13384SDavid Stevens return shmem_is_huge(file_inode(vma->vm_file), vma->vm_pgoff, 1503485b883SRyan Roberts !enforce_sysfs, vma->vm_mm, vm_flags) 1513485b883SRyan Roberts ? orders : 0; 1529fec5168SYang Shi 1537a81751fSZach O'Keefe if (!vma_is_anonymous(vma)) { 1547a81751fSZach O'Keefe /* 1553485b883SRyan Roberts * Enforce sysfs THP requirements as necessary. Anonymous vmas 1563485b883SRyan Roberts * were already handled in thp_vma_allowable_orders(). 1573485b883SRyan Roberts */ 1583485b883SRyan Roberts if (enforce_sysfs && 1593485b883SRyan Roberts (!hugepage_global_enabled() || (!(vm_flags & VM_HUGEPAGE) && 1603485b883SRyan Roberts !hugepage_global_always()))) 1613485b883SRyan Roberts return 0; 1623485b883SRyan Roberts 1633485b883SRyan Roberts /* 1647a81751fSZach O'Keefe * Trust that ->huge_fault() handlers know what they are doing 1657a81751fSZach O'Keefe * in fault path. 1667a81751fSZach O'Keefe */ 1677a81751fSZach O'Keefe if (((in_pf || smaps)) && vma->vm_ops->huge_fault) 1683485b883SRyan Roberts return orders; 1697a81751fSZach O'Keefe /* Only regular file is valid in collapse path */ 1707a81751fSZach O'Keefe if (((!in_pf || smaps)) && file_thp_enabled(vma)) 1713485b883SRyan Roberts return orders; 1723485b883SRyan Roberts return 0; 1737a81751fSZach O'Keefe } 1749fec5168SYang Shi 1759fec5168SYang Shi if (vma_is_temporary_stack(vma)) 1763485b883SRyan Roberts return 0; 1779fec5168SYang Shi 1789fec5168SYang Shi /* 1799fec5168SYang Shi * THPeligible bit of smaps should show 1 for proper VMAs even 1809fec5168SYang Shi * though anon_vma is not initialized yet. 1817da4e2cbSYang Shi * 1827da4e2cbSYang Shi * Allow page fault since anon_vma may be not initialized until 1837da4e2cbSYang Shi * the first page fault. 1849fec5168SYang Shi */ 1859fec5168SYang Shi if (!vma->anon_vma) 1863485b883SRyan Roberts return (smaps || in_pf) ? orders : 0; 1879fec5168SYang Shi 1883485b883SRyan Roberts return orders; 1897635d9cbSMichal Hocko } 1907635d9cbSMichal Hocko 191aaa9705bSMiaohe Lin static bool get_huge_zero_page(void) 19297ae1749SKirill A. Shutemov { 19397ae1749SKirill A. Shutemov struct page *zero_page; 19497ae1749SKirill A. Shutemov retry: 19597ae1749SKirill A. Shutemov if (likely(atomic_inc_not_zero(&huge_zero_refcount))) 196aaa9705bSMiaohe Lin return true; 19797ae1749SKirill A. Shutemov 19897ae1749SKirill A. Shutemov zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, 19997ae1749SKirill A. Shutemov HPAGE_PMD_ORDER); 200d8a8e1f0SKirill A. Shutemov if (!zero_page) { 201d8a8e1f0SKirill A. Shutemov count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); 202aaa9705bSMiaohe Lin return false; 203d8a8e1f0SKirill A. Shutemov } 20497ae1749SKirill A. Shutemov preempt_disable(); 2055918d10aSKirill A. Shutemov if (cmpxchg(&huge_zero_page, NULL, zero_page)) { 20697ae1749SKirill A. Shutemov preempt_enable(); 2075ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 20897ae1749SKirill A. Shutemov goto retry; 20997ae1749SKirill A. Shutemov } 2103b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); 21197ae1749SKirill A. Shutemov 21297ae1749SKirill A. Shutemov /* We take additional reference here. It will be put back by shrinker */ 21397ae1749SKirill A. Shutemov atomic_set(&huge_zero_refcount, 2); 21497ae1749SKirill A. Shutemov preempt_enable(); 215f4981502SLiu Shixin count_vm_event(THP_ZERO_PAGE_ALLOC); 216aaa9705bSMiaohe Lin return true; 21797ae1749SKirill A. Shutemov } 21897ae1749SKirill A. Shutemov 2196fcb52a5SAaron Lu static void put_huge_zero_page(void) 22097ae1749SKirill A. Shutemov { 22197ae1749SKirill A. Shutemov /* 22297ae1749SKirill A. Shutemov * Counter should never go to zero here. Only shrinker can put 22397ae1749SKirill A. Shutemov * last reference. 22497ae1749SKirill A. Shutemov */ 22597ae1749SKirill A. Shutemov BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); 22697ae1749SKirill A. Shutemov } 22797ae1749SKirill A. Shutemov 2286fcb52a5SAaron Lu struct page *mm_get_huge_zero_page(struct mm_struct *mm) 2296fcb52a5SAaron Lu { 2306fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2316fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 2326fcb52a5SAaron Lu 2336fcb52a5SAaron Lu if (!get_huge_zero_page()) 2346fcb52a5SAaron Lu return NULL; 2356fcb52a5SAaron Lu 2366fcb52a5SAaron Lu if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2376fcb52a5SAaron Lu put_huge_zero_page(); 2386fcb52a5SAaron Lu 2396fcb52a5SAaron Lu return READ_ONCE(huge_zero_page); 2406fcb52a5SAaron Lu } 2416fcb52a5SAaron Lu 2426fcb52a5SAaron Lu void mm_put_huge_zero_page(struct mm_struct *mm) 2436fcb52a5SAaron Lu { 2446fcb52a5SAaron Lu if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) 2456fcb52a5SAaron Lu put_huge_zero_page(); 2466fcb52a5SAaron Lu } 2476fcb52a5SAaron Lu 24848896466SGlauber Costa static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, 24997ae1749SKirill A. Shutemov struct shrink_control *sc) 25097ae1749SKirill A. Shutemov { 25197ae1749SKirill A. Shutemov /* we can free zero page only if last reference remains */ 25297ae1749SKirill A. Shutemov return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; 25348896466SGlauber Costa } 25497ae1749SKirill A. Shutemov 25548896466SGlauber Costa static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, 25648896466SGlauber Costa struct shrink_control *sc) 25748896466SGlauber Costa { 25897ae1749SKirill A. Shutemov if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { 2595918d10aSKirill A. Shutemov struct page *zero_page = xchg(&huge_zero_page, NULL); 2605918d10aSKirill A. Shutemov BUG_ON(zero_page == NULL); 2613b77e8c8SHugh Dickins WRITE_ONCE(huge_zero_pfn, ~0UL); 2625ddacbe9SYu Zhao __free_pages(zero_page, compound_order(zero_page)); 26348896466SGlauber Costa return HPAGE_PMD_NR; 26497ae1749SKirill A. Shutemov } 26597ae1749SKirill A. Shutemov 26697ae1749SKirill A. Shutemov return 0; 26797ae1749SKirill A. Shutemov } 26897ae1749SKirill A. Shutemov 26954d91729SQi Zheng static struct shrinker *huge_zero_page_shrinker; 27097ae1749SKirill A. Shutemov 27171e3aac0SAndrea Arcangeli #ifdef CONFIG_SYSFS 27271e3aac0SAndrea Arcangeli static ssize_t enabled_show(struct kobject *kobj, 27371e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 27471e3aac0SAndrea Arcangeli { 275bfb0ffebSJoe Perches const char *output; 276bfb0ffebSJoe Perches 277444eb2a4SMel Gorman if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) 278bfb0ffebSJoe Perches output = "[always] madvise never"; 279bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 280bfb0ffebSJoe Perches &transparent_hugepage_flags)) 281bfb0ffebSJoe Perches output = "always [madvise] never"; 282444eb2a4SMel Gorman else 283bfb0ffebSJoe Perches output = "always madvise [never]"; 284bfb0ffebSJoe Perches 285bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 28671e3aac0SAndrea Arcangeli } 287444eb2a4SMel Gorman 28871e3aac0SAndrea Arcangeli static ssize_t enabled_store(struct kobject *kobj, 28971e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 29071e3aac0SAndrea Arcangeli const char *buf, size_t count) 29171e3aac0SAndrea Arcangeli { 29221440d7eSDavid Rientjes ssize_t ret = count; 293ba76149fSAndrea Arcangeli 294f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 29521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 29621440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 297f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 29821440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 29921440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 300f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 30121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); 30221440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); 30321440d7eSDavid Rientjes } else 30421440d7eSDavid Rientjes ret = -EINVAL; 305ba76149fSAndrea Arcangeli 306ba76149fSAndrea Arcangeli if (ret > 0) { 307b46e756fSKirill A. Shutemov int err = start_stop_khugepaged(); 308ba76149fSAndrea Arcangeli if (err) 309ba76149fSAndrea Arcangeli ret = err; 310ba76149fSAndrea Arcangeli } 311ba76149fSAndrea Arcangeli return ret; 31271e3aac0SAndrea Arcangeli } 31337139bb0SMiaohe Lin 31437139bb0SMiaohe Lin static struct kobj_attribute enabled_attr = __ATTR_RW(enabled); 31571e3aac0SAndrea Arcangeli 316b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_show(struct kobject *kobj, 31771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf, 31871e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 31971e3aac0SAndrea Arcangeli { 320bfb0ffebSJoe Perches return sysfs_emit(buf, "%d\n", 321e27e6151SBen Hutchings !!test_bit(flag, &transparent_hugepage_flags)); 32271e3aac0SAndrea Arcangeli } 323e27e6151SBen Hutchings 324b46e756fSKirill A. Shutemov ssize_t single_hugepage_flag_store(struct kobject *kobj, 32571e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 32671e3aac0SAndrea Arcangeli const char *buf, size_t count, 32771e3aac0SAndrea Arcangeli enum transparent_hugepage_flag flag) 32871e3aac0SAndrea Arcangeli { 329e27e6151SBen Hutchings unsigned long value; 330e27e6151SBen Hutchings int ret; 331e27e6151SBen Hutchings 332e27e6151SBen Hutchings ret = kstrtoul(buf, 10, &value); 333e27e6151SBen Hutchings if (ret < 0) 334e27e6151SBen Hutchings return ret; 335e27e6151SBen Hutchings if (value > 1) 33671e3aac0SAndrea Arcangeli return -EINVAL; 33771e3aac0SAndrea Arcangeli 338e27e6151SBen Hutchings if (value) 339e27e6151SBen Hutchings set_bit(flag, &transparent_hugepage_flags); 340e27e6151SBen Hutchings else 341e27e6151SBen Hutchings clear_bit(flag, &transparent_hugepage_flags); 342e27e6151SBen Hutchings 34371e3aac0SAndrea Arcangeli return count; 34471e3aac0SAndrea Arcangeli } 34571e3aac0SAndrea Arcangeli 34671e3aac0SAndrea Arcangeli static ssize_t defrag_show(struct kobject *kobj, 34771e3aac0SAndrea Arcangeli struct kobj_attribute *attr, char *buf) 34871e3aac0SAndrea Arcangeli { 349bfb0ffebSJoe Perches const char *output; 350bfb0ffebSJoe Perches 351bfb0ffebSJoe Perches if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, 352bfb0ffebSJoe Perches &transparent_hugepage_flags)) 353bfb0ffebSJoe Perches output = "[always] defer defer+madvise madvise never"; 354bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, 355bfb0ffebSJoe Perches &transparent_hugepage_flags)) 356bfb0ffebSJoe Perches output = "always [defer] defer+madvise madvise never"; 357bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, 358bfb0ffebSJoe Perches &transparent_hugepage_flags)) 359bfb0ffebSJoe Perches output = "always defer [defer+madvise] madvise never"; 360bfb0ffebSJoe Perches else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, 361bfb0ffebSJoe Perches &transparent_hugepage_flags)) 362bfb0ffebSJoe Perches output = "always defer defer+madvise [madvise] never"; 363bfb0ffebSJoe Perches else 364bfb0ffebSJoe Perches output = "always defer defer+madvise madvise [never]"; 365bfb0ffebSJoe Perches 366bfb0ffebSJoe Perches return sysfs_emit(buf, "%s\n", output); 36771e3aac0SAndrea Arcangeli } 36821440d7eSDavid Rientjes 36971e3aac0SAndrea Arcangeli static ssize_t defrag_store(struct kobject *kobj, 37071e3aac0SAndrea Arcangeli struct kobj_attribute *attr, 37171e3aac0SAndrea Arcangeli const char *buf, size_t count) 37271e3aac0SAndrea Arcangeli { 373f42f2552SDavid Rientjes if (sysfs_streq(buf, "always")) { 37421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 37521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 37621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 37721440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 378f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer+madvise")) { 37921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 38021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 38121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 38221440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 383f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "defer")) { 3844fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 3854fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 3864fad7fb6SDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 3874fad7fb6SDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 388f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "madvise")) { 38921440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 39021440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 39121440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 39221440d7eSDavid Rientjes set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 393f42f2552SDavid Rientjes } else if (sysfs_streq(buf, "never")) { 39421440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); 39521440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); 39621440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); 39721440d7eSDavid Rientjes clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); 39821440d7eSDavid Rientjes } else 39921440d7eSDavid Rientjes return -EINVAL; 40021440d7eSDavid Rientjes 40121440d7eSDavid Rientjes return count; 40271e3aac0SAndrea Arcangeli } 40337139bb0SMiaohe Lin static struct kobj_attribute defrag_attr = __ATTR_RW(defrag); 40471e3aac0SAndrea Arcangeli 40579da5407SKirill A. Shutemov static ssize_t use_zero_page_show(struct kobject *kobj, 40679da5407SKirill A. Shutemov struct kobj_attribute *attr, char *buf) 40779da5407SKirill A. Shutemov { 408b46e756fSKirill A. Shutemov return single_hugepage_flag_show(kobj, attr, buf, 40979da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 41079da5407SKirill A. Shutemov } 41179da5407SKirill A. Shutemov static ssize_t use_zero_page_store(struct kobject *kobj, 41279da5407SKirill A. Shutemov struct kobj_attribute *attr, const char *buf, size_t count) 41379da5407SKirill A. Shutemov { 414b46e756fSKirill A. Shutemov return single_hugepage_flag_store(kobj, attr, buf, count, 41579da5407SKirill A. Shutemov TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); 41679da5407SKirill A. Shutemov } 41737139bb0SMiaohe Lin static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page); 41849920d28SHugh Dickins 41949920d28SHugh Dickins static ssize_t hpage_pmd_size_show(struct kobject *kobj, 42049920d28SHugh Dickins struct kobj_attribute *attr, char *buf) 42149920d28SHugh Dickins { 422ae7a927dSJoe Perches return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); 42349920d28SHugh Dickins } 42449920d28SHugh Dickins static struct kobj_attribute hpage_pmd_size_attr = 42549920d28SHugh Dickins __ATTR_RO(hpage_pmd_size); 42649920d28SHugh Dickins 42771e3aac0SAndrea Arcangeli static struct attribute *hugepage_attr[] = { 42871e3aac0SAndrea Arcangeli &enabled_attr.attr, 42971e3aac0SAndrea Arcangeli &defrag_attr.attr, 43079da5407SKirill A. Shutemov &use_zero_page_attr.attr, 43149920d28SHugh Dickins &hpage_pmd_size_attr.attr, 432396bcc52SMatthew Wilcox (Oracle) #ifdef CONFIG_SHMEM 4335a6e75f8SKirill A. Shutemov &shmem_enabled_attr.attr, 4345a6e75f8SKirill A. Shutemov #endif 43571e3aac0SAndrea Arcangeli NULL, 43671e3aac0SAndrea Arcangeli }; 43771e3aac0SAndrea Arcangeli 4388aa95a21SArvind Yadav static const struct attribute_group hugepage_attr_group = { 43971e3aac0SAndrea Arcangeli .attrs = hugepage_attr, 440ba76149fSAndrea Arcangeli }; 441ba76149fSAndrea Arcangeli 4423485b883SRyan Roberts static void hugepage_exit_sysfs(struct kobject *hugepage_kobj); 4433485b883SRyan Roberts static void thpsize_release(struct kobject *kobj); 4443485b883SRyan Roberts static DEFINE_SPINLOCK(huge_anon_orders_lock); 4453485b883SRyan Roberts static LIST_HEAD(thpsize_list); 4463485b883SRyan Roberts 4473485b883SRyan Roberts struct thpsize { 4483485b883SRyan Roberts struct kobject kobj; 4493485b883SRyan Roberts struct list_head node; 4503485b883SRyan Roberts int order; 4513485b883SRyan Roberts }; 4523485b883SRyan Roberts 4533485b883SRyan Roberts #define to_thpsize(kobj) container_of(kobj, struct thpsize, kobj) 4543485b883SRyan Roberts 4553485b883SRyan Roberts static ssize_t thpsize_enabled_show(struct kobject *kobj, 4563485b883SRyan Roberts struct kobj_attribute *attr, char *buf) 4573485b883SRyan Roberts { 4583485b883SRyan Roberts int order = to_thpsize(kobj)->order; 4593485b883SRyan Roberts const char *output; 4603485b883SRyan Roberts 4613485b883SRyan Roberts if (test_bit(order, &huge_anon_orders_always)) 4623485b883SRyan Roberts output = "[always] inherit madvise never"; 4633485b883SRyan Roberts else if (test_bit(order, &huge_anon_orders_inherit)) 4643485b883SRyan Roberts output = "always [inherit] madvise never"; 4653485b883SRyan Roberts else if (test_bit(order, &huge_anon_orders_madvise)) 4663485b883SRyan Roberts output = "always inherit [madvise] never"; 4673485b883SRyan Roberts else 4683485b883SRyan Roberts output = "always inherit madvise [never]"; 4693485b883SRyan Roberts 4703485b883SRyan Roberts return sysfs_emit(buf, "%s\n", output); 4713485b883SRyan Roberts } 4723485b883SRyan Roberts 4733485b883SRyan Roberts static ssize_t thpsize_enabled_store(struct kobject *kobj, 4743485b883SRyan Roberts struct kobj_attribute *attr, 4753485b883SRyan Roberts const char *buf, size_t count) 4763485b883SRyan Roberts { 4773485b883SRyan Roberts int order = to_thpsize(kobj)->order; 4783485b883SRyan Roberts ssize_t ret = count; 4793485b883SRyan Roberts 4803485b883SRyan Roberts if (sysfs_streq(buf, "always")) { 4813485b883SRyan Roberts spin_lock(&huge_anon_orders_lock); 4823485b883SRyan Roberts clear_bit(order, &huge_anon_orders_inherit); 4833485b883SRyan Roberts clear_bit(order, &huge_anon_orders_madvise); 4843485b883SRyan Roberts set_bit(order, &huge_anon_orders_always); 4853485b883SRyan Roberts spin_unlock(&huge_anon_orders_lock); 4863485b883SRyan Roberts } else if (sysfs_streq(buf, "inherit")) { 4873485b883SRyan Roberts spin_lock(&huge_anon_orders_lock); 4883485b883SRyan Roberts clear_bit(order, &huge_anon_orders_always); 4893485b883SRyan Roberts clear_bit(order, &huge_anon_orders_madvise); 4903485b883SRyan Roberts set_bit(order, &huge_anon_orders_inherit); 4913485b883SRyan Roberts spin_unlock(&huge_anon_orders_lock); 4923485b883SRyan Roberts } else if (sysfs_streq(buf, "madvise")) { 4933485b883SRyan Roberts spin_lock(&huge_anon_orders_lock); 4943485b883SRyan Roberts clear_bit(order, &huge_anon_orders_always); 4953485b883SRyan Roberts clear_bit(order, &huge_anon_orders_inherit); 4963485b883SRyan Roberts set_bit(order, &huge_anon_orders_madvise); 4973485b883SRyan Roberts spin_unlock(&huge_anon_orders_lock); 4983485b883SRyan Roberts } else if (sysfs_streq(buf, "never")) { 4993485b883SRyan Roberts spin_lock(&huge_anon_orders_lock); 5003485b883SRyan Roberts clear_bit(order, &huge_anon_orders_always); 5013485b883SRyan Roberts clear_bit(order, &huge_anon_orders_inherit); 5023485b883SRyan Roberts clear_bit(order, &huge_anon_orders_madvise); 5033485b883SRyan Roberts spin_unlock(&huge_anon_orders_lock); 5043485b883SRyan Roberts } else 5053485b883SRyan Roberts ret = -EINVAL; 5063485b883SRyan Roberts 5073485b883SRyan Roberts return ret; 5083485b883SRyan Roberts } 5093485b883SRyan Roberts 5103485b883SRyan Roberts static struct kobj_attribute thpsize_enabled_attr = 5113485b883SRyan Roberts __ATTR(enabled, 0644, thpsize_enabled_show, thpsize_enabled_store); 5123485b883SRyan Roberts 5133485b883SRyan Roberts static struct attribute *thpsize_attrs[] = { 5143485b883SRyan Roberts &thpsize_enabled_attr.attr, 5153485b883SRyan Roberts NULL, 5163485b883SRyan Roberts }; 5173485b883SRyan Roberts 5183485b883SRyan Roberts static const struct attribute_group thpsize_attr_group = { 5193485b883SRyan Roberts .attrs = thpsize_attrs, 5203485b883SRyan Roberts }; 5213485b883SRyan Roberts 5223485b883SRyan Roberts static const struct kobj_type thpsize_ktype = { 5233485b883SRyan Roberts .release = &thpsize_release, 5243485b883SRyan Roberts .sysfs_ops = &kobj_sysfs_ops, 5253485b883SRyan Roberts }; 5263485b883SRyan Roberts 5273485b883SRyan Roberts static struct thpsize *thpsize_create(int order, struct kobject *parent) 5283485b883SRyan Roberts { 5293485b883SRyan Roberts unsigned long size = (PAGE_SIZE << order) / SZ_1K; 5303485b883SRyan Roberts struct thpsize *thpsize; 5313485b883SRyan Roberts int ret; 5323485b883SRyan Roberts 5333485b883SRyan Roberts thpsize = kzalloc(sizeof(*thpsize), GFP_KERNEL); 5343485b883SRyan Roberts if (!thpsize) 5353485b883SRyan Roberts return ERR_PTR(-ENOMEM); 5363485b883SRyan Roberts 5373485b883SRyan Roberts ret = kobject_init_and_add(&thpsize->kobj, &thpsize_ktype, parent, 5383485b883SRyan Roberts "hugepages-%lukB", size); 5393485b883SRyan Roberts if (ret) { 5403485b883SRyan Roberts kfree(thpsize); 5413485b883SRyan Roberts return ERR_PTR(ret); 5423485b883SRyan Roberts } 5433485b883SRyan Roberts 5443485b883SRyan Roberts ret = sysfs_create_group(&thpsize->kobj, &thpsize_attr_group); 5453485b883SRyan Roberts if (ret) { 5463485b883SRyan Roberts kobject_put(&thpsize->kobj); 5473485b883SRyan Roberts return ERR_PTR(ret); 5483485b883SRyan Roberts } 5493485b883SRyan Roberts 5503485b883SRyan Roberts thpsize->order = order; 5513485b883SRyan Roberts return thpsize; 5523485b883SRyan Roberts } 5533485b883SRyan Roberts 5543485b883SRyan Roberts static void thpsize_release(struct kobject *kobj) 5553485b883SRyan Roberts { 5563485b883SRyan Roberts kfree(to_thpsize(kobj)); 5573485b883SRyan Roberts } 5583485b883SRyan Roberts 559569e5590SShaohua Li static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) 560569e5590SShaohua Li { 561569e5590SShaohua Li int err; 5623485b883SRyan Roberts struct thpsize *thpsize; 5633485b883SRyan Roberts unsigned long orders; 5643485b883SRyan Roberts int order; 5653485b883SRyan Roberts 5663485b883SRyan Roberts /* 5673485b883SRyan Roberts * Default to setting PMD-sized THP to inherit the global setting and 5683485b883SRyan Roberts * disable all other sizes. powerpc's PMD_ORDER isn't a compile-time 5693485b883SRyan Roberts * constant so we have to do this here. 5703485b883SRyan Roberts */ 5713485b883SRyan Roberts huge_anon_orders_inherit = BIT(PMD_ORDER); 572569e5590SShaohua Li 573569e5590SShaohua Li *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); 574569e5590SShaohua Li if (unlikely(!*hugepage_kobj)) { 575ae3a8c1cSAndrew Morton pr_err("failed to create transparent hugepage kobject\n"); 576569e5590SShaohua Li return -ENOMEM; 577569e5590SShaohua Li } 578569e5590SShaohua Li 579569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); 580569e5590SShaohua Li if (err) { 581ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 582569e5590SShaohua Li goto delete_obj; 583569e5590SShaohua Li } 584569e5590SShaohua Li 585569e5590SShaohua Li err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); 586569e5590SShaohua Li if (err) { 587ae3a8c1cSAndrew Morton pr_err("failed to register transparent hugepage group\n"); 588569e5590SShaohua Li goto remove_hp_group; 589569e5590SShaohua Li } 590569e5590SShaohua Li 5913485b883SRyan Roberts orders = THP_ORDERS_ALL_ANON; 5923485b883SRyan Roberts order = highest_order(orders); 5933485b883SRyan Roberts while (orders) { 5943485b883SRyan Roberts thpsize = thpsize_create(order, *hugepage_kobj); 5953485b883SRyan Roberts if (IS_ERR(thpsize)) { 5963485b883SRyan Roberts pr_err("failed to create thpsize for order %d\n", order); 5973485b883SRyan Roberts err = PTR_ERR(thpsize); 5983485b883SRyan Roberts goto remove_all; 5993485b883SRyan Roberts } 6003485b883SRyan Roberts list_add(&thpsize->node, &thpsize_list); 6013485b883SRyan Roberts order = next_order(&orders, order); 6023485b883SRyan Roberts } 6033485b883SRyan Roberts 604569e5590SShaohua Li return 0; 605569e5590SShaohua Li 6063485b883SRyan Roberts remove_all: 6073485b883SRyan Roberts hugepage_exit_sysfs(*hugepage_kobj); 6083485b883SRyan Roberts return err; 609569e5590SShaohua Li remove_hp_group: 610569e5590SShaohua Li sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); 611569e5590SShaohua Li delete_obj: 612569e5590SShaohua Li kobject_put(*hugepage_kobj); 613569e5590SShaohua Li return err; 614569e5590SShaohua Li } 615569e5590SShaohua Li 616569e5590SShaohua Li static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) 617569e5590SShaohua Li { 6183485b883SRyan Roberts struct thpsize *thpsize, *tmp; 6193485b883SRyan Roberts 6203485b883SRyan Roberts list_for_each_entry_safe(thpsize, tmp, &thpsize_list, node) { 6213485b883SRyan Roberts list_del(&thpsize->node); 6223485b883SRyan Roberts kobject_put(&thpsize->kobj); 6233485b883SRyan Roberts } 6243485b883SRyan Roberts 625569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); 626569e5590SShaohua Li sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); 627569e5590SShaohua Li kobject_put(hugepage_kobj); 628569e5590SShaohua Li } 629569e5590SShaohua Li #else 630569e5590SShaohua Li static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) 631569e5590SShaohua Li { 632569e5590SShaohua Li return 0; 633569e5590SShaohua Li } 634569e5590SShaohua Li 635569e5590SShaohua Li static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) 636569e5590SShaohua Li { 637569e5590SShaohua Li } 63871e3aac0SAndrea Arcangeli #endif /* CONFIG_SYSFS */ 63971e3aac0SAndrea Arcangeli 64054d91729SQi Zheng static int __init thp_shrinker_init(void) 64154d91729SQi Zheng { 64254d91729SQi Zheng huge_zero_page_shrinker = shrinker_alloc(0, "thp-zero"); 64354d91729SQi Zheng if (!huge_zero_page_shrinker) 64454d91729SQi Zheng return -ENOMEM; 64554d91729SQi Zheng 64654d91729SQi Zheng deferred_split_shrinker = shrinker_alloc(SHRINKER_NUMA_AWARE | 64754d91729SQi Zheng SHRINKER_MEMCG_AWARE | 64854d91729SQi Zheng SHRINKER_NONSLAB, 64954d91729SQi Zheng "thp-deferred_split"); 65054d91729SQi Zheng if (!deferred_split_shrinker) { 65154d91729SQi Zheng shrinker_free(huge_zero_page_shrinker); 65254d91729SQi Zheng return -ENOMEM; 65354d91729SQi Zheng } 65454d91729SQi Zheng 65554d91729SQi Zheng huge_zero_page_shrinker->count_objects = shrink_huge_zero_page_count; 65654d91729SQi Zheng huge_zero_page_shrinker->scan_objects = shrink_huge_zero_page_scan; 65754d91729SQi Zheng shrinker_register(huge_zero_page_shrinker); 65854d91729SQi Zheng 65954d91729SQi Zheng deferred_split_shrinker->count_objects = deferred_split_count; 66054d91729SQi Zheng deferred_split_shrinker->scan_objects = deferred_split_scan; 66154d91729SQi Zheng shrinker_register(deferred_split_shrinker); 66254d91729SQi Zheng 66354d91729SQi Zheng return 0; 66454d91729SQi Zheng } 66554d91729SQi Zheng 66654d91729SQi Zheng static void __init thp_shrinker_exit(void) 66754d91729SQi Zheng { 66854d91729SQi Zheng shrinker_free(huge_zero_page_shrinker); 66954d91729SQi Zheng shrinker_free(deferred_split_shrinker); 67054d91729SQi Zheng } 67154d91729SQi Zheng 67271e3aac0SAndrea Arcangeli static int __init hugepage_init(void) 67371e3aac0SAndrea Arcangeli { 67471e3aac0SAndrea Arcangeli int err; 675569e5590SShaohua Li struct kobject *hugepage_kobj; 67671e3aac0SAndrea Arcangeli 6774b7167b9SAndrea Arcangeli if (!has_transparent_hugepage()) { 6783c556d24SPeter Xu transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED; 679569e5590SShaohua Li return -EINVAL; 6804b7167b9SAndrea Arcangeli } 6814b7167b9SAndrea Arcangeli 682ff20c2e0SKirill A. Shutemov /* 683ff20c2e0SKirill A. Shutemov * hugepages can't be allocated by the buddy allocator 684ff20c2e0SKirill A. Shutemov */ 68523baf831SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER > MAX_ORDER); 686ff20c2e0SKirill A. Shutemov /* 687ff20c2e0SKirill A. Shutemov * we use page->mapping and page->index in second tail page 688ff20c2e0SKirill A. Shutemov * as list_head: assuming THP order >= 2 689ff20c2e0SKirill A. Shutemov */ 690ff20c2e0SKirill A. Shutemov MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); 691ff20c2e0SKirill A. Shutemov 692569e5590SShaohua Li err = hugepage_init_sysfs(&hugepage_kobj); 693569e5590SShaohua Li if (err) 69465ebb64fSKirill A. Shutemov goto err_sysfs; 695ba76149fSAndrea Arcangeli 696b46e756fSKirill A. Shutemov err = khugepaged_init(); 697ba76149fSAndrea Arcangeli if (err) 69865ebb64fSKirill A. Shutemov goto err_slab; 699ba76149fSAndrea Arcangeli 70054d91729SQi Zheng err = thp_shrinker_init(); 70165ebb64fSKirill A. Shutemov if (err) 70254d91729SQi Zheng goto err_shrinker; 70397ae1749SKirill A. Shutemov 70497562cd2SRik van Riel /* 70597562cd2SRik van Riel * By default disable transparent hugepages on smaller systems, 70697562cd2SRik van Riel * where the extra memory used could hurt more than TLB overhead 70797562cd2SRik van Riel * is likely to save. The admin can still enable it through /sys. 70897562cd2SRik van Riel */ 709ca79b0c2SArun KS if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { 71097562cd2SRik van Riel transparent_hugepage_flags = 0; 71179553da2SKirill A. Shutemov return 0; 71279553da2SKirill A. Shutemov } 71397562cd2SRik van Riel 71479553da2SKirill A. Shutemov err = start_stop_khugepaged(); 71565ebb64fSKirill A. Shutemov if (err) 71665ebb64fSKirill A. Shutemov goto err_khugepaged; 717ba76149fSAndrea Arcangeli 718569e5590SShaohua Li return 0; 71965ebb64fSKirill A. Shutemov err_khugepaged: 72054d91729SQi Zheng thp_shrinker_exit(); 72154d91729SQi Zheng err_shrinker: 722b46e756fSKirill A. Shutemov khugepaged_destroy(); 72365ebb64fSKirill A. Shutemov err_slab: 724569e5590SShaohua Li hugepage_exit_sysfs(hugepage_kobj); 72565ebb64fSKirill A. Shutemov err_sysfs: 726ba76149fSAndrea Arcangeli return err; 72771e3aac0SAndrea Arcangeli } 728a64fb3cdSPaul Gortmaker subsys_initcall(hugepage_init); 72971e3aac0SAndrea Arcangeli 73071e3aac0SAndrea Arcangeli static int __init setup_transparent_hugepage(char *str) 73171e3aac0SAndrea Arcangeli { 73271e3aac0SAndrea Arcangeli int ret = 0; 73371e3aac0SAndrea Arcangeli if (!str) 73471e3aac0SAndrea Arcangeli goto out; 73571e3aac0SAndrea Arcangeli if (!strcmp(str, "always")) { 73671e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_FLAG, 73771e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 73871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 73971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 74071e3aac0SAndrea Arcangeli ret = 1; 74171e3aac0SAndrea Arcangeli } else if (!strcmp(str, "madvise")) { 74271e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 74371e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 74471e3aac0SAndrea Arcangeli set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 74571e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 74671e3aac0SAndrea Arcangeli ret = 1; 74771e3aac0SAndrea Arcangeli } else if (!strcmp(str, "never")) { 74871e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_FLAG, 74971e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 75071e3aac0SAndrea Arcangeli clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, 75171e3aac0SAndrea Arcangeli &transparent_hugepage_flags); 75271e3aac0SAndrea Arcangeli ret = 1; 75371e3aac0SAndrea Arcangeli } 75471e3aac0SAndrea Arcangeli out: 75571e3aac0SAndrea Arcangeli if (!ret) 756ae3a8c1cSAndrew Morton pr_warn("transparent_hugepage= cannot parse, ignored\n"); 75771e3aac0SAndrea Arcangeli return ret; 75871e3aac0SAndrea Arcangeli } 75971e3aac0SAndrea Arcangeli __setup("transparent_hugepage=", setup_transparent_hugepage); 76071e3aac0SAndrea Arcangeli 761f55e1014SLinus Torvalds pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) 76271e3aac0SAndrea Arcangeli { 763f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 764161e393cSRick Edgecombe pmd = pmd_mkwrite(pmd, vma); 76571e3aac0SAndrea Arcangeli return pmd; 76671e3aac0SAndrea Arcangeli } 76771e3aac0SAndrea Arcangeli 76887eaceb3SYang Shi #ifdef CONFIG_MEMCG 769f8baa6beSMatthew Wilcox (Oracle) static inline 770f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *get_deferred_split_queue(struct folio *folio) 7719a982250SKirill A. Shutemov { 772f8baa6beSMatthew Wilcox (Oracle) struct mem_cgroup *memcg = folio_memcg(folio); 773f8baa6beSMatthew Wilcox (Oracle) struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); 77487eaceb3SYang Shi 77587eaceb3SYang Shi if (memcg) 77687eaceb3SYang Shi return &memcg->deferred_split_queue; 77787eaceb3SYang Shi else 77887eaceb3SYang Shi return &pgdat->deferred_split_queue; 7799a982250SKirill A. Shutemov } 78087eaceb3SYang Shi #else 781f8baa6beSMatthew Wilcox (Oracle) static inline 782f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *get_deferred_split_queue(struct folio *folio) 78387eaceb3SYang Shi { 784f8baa6beSMatthew Wilcox (Oracle) struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); 78587eaceb3SYang Shi 78687eaceb3SYang Shi return &pgdat->deferred_split_queue; 78787eaceb3SYang Shi } 78887eaceb3SYang Shi #endif 7899a982250SKirill A. Shutemov 790da6e7bf3SMatthew Wilcox (Oracle) void folio_prep_large_rmappable(struct folio *folio) 7919a982250SKirill A. Shutemov { 7928991de90SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); 7938991de90SMatthew Wilcox (Oracle) INIT_LIST_HEAD(&folio->_deferred_list); 794de53c05fSMatthew Wilcox (Oracle) folio_set_large_rmappable(folio); 7959a982250SKirill A. Shutemov } 7969a982250SKirill A. Shutemov 797a644b0abSMatthew Wilcox (Oracle) static inline bool is_transparent_hugepage(struct folio *folio) 798005ba37cSSean Christopherson { 799a644b0abSMatthew Wilcox (Oracle) if (!folio_test_large(folio)) 800fa1f68ccSZou Wei return false; 801005ba37cSSean Christopherson 802f04029f3SMatthew Wilcox (Oracle) return is_huge_zero_page(&folio->page) || 803de53c05fSMatthew Wilcox (Oracle) folio_test_large_rmappable(folio); 804005ba37cSSean Christopherson } 805005ba37cSSean Christopherson 80697d3d0f9SKirill A. Shutemov static unsigned long __thp_get_unmapped_area(struct file *filp, 80797d3d0f9SKirill A. Shutemov unsigned long addr, unsigned long len, 80874d2fad1SToshi Kani loff_t off, unsigned long flags, unsigned long size) 80974d2fad1SToshi Kani { 81074d2fad1SToshi Kani loff_t off_end = off + len; 81174d2fad1SToshi Kani loff_t off_align = round_up(off, size); 81297d3d0f9SKirill A. Shutemov unsigned long len_pad, ret; 81374d2fad1SToshi Kani 81474d2fad1SToshi Kani if (off_end <= off_align || (off_end - off_align) < size) 81574d2fad1SToshi Kani return 0; 81674d2fad1SToshi Kani 81774d2fad1SToshi Kani len_pad = len + size; 81874d2fad1SToshi Kani if (len_pad < len || (off + len_pad) < off) 81974d2fad1SToshi Kani return 0; 82074d2fad1SToshi Kani 82197d3d0f9SKirill A. Shutemov ret = current->mm->get_unmapped_area(filp, addr, len_pad, 82274d2fad1SToshi Kani off >> PAGE_SHIFT, flags); 82397d3d0f9SKirill A. Shutemov 82497d3d0f9SKirill A. Shutemov /* 82597d3d0f9SKirill A. Shutemov * The failure might be due to length padding. The caller will retry 82697d3d0f9SKirill A. Shutemov * without the padding. 82797d3d0f9SKirill A. Shutemov */ 82897d3d0f9SKirill A. Shutemov if (IS_ERR_VALUE(ret)) 82974d2fad1SToshi Kani return 0; 83074d2fad1SToshi Kani 83197d3d0f9SKirill A. Shutemov /* 83297d3d0f9SKirill A. Shutemov * Do not try to align to THP boundary if allocation at the address 83397d3d0f9SKirill A. Shutemov * hint succeeds. 83497d3d0f9SKirill A. Shutemov */ 83597d3d0f9SKirill A. Shutemov if (ret == addr) 83674d2fad1SToshi Kani return addr; 83797d3d0f9SKirill A. Shutemov 83897d3d0f9SKirill A. Shutemov ret += (off - ret) & (size - 1); 83997d3d0f9SKirill A. Shutemov return ret; 84074d2fad1SToshi Kani } 84174d2fad1SToshi Kani 84274d2fad1SToshi Kani unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, 84374d2fad1SToshi Kani unsigned long len, unsigned long pgoff, unsigned long flags) 84474d2fad1SToshi Kani { 84597d3d0f9SKirill A. Shutemov unsigned long ret; 84674d2fad1SToshi Kani loff_t off = (loff_t)pgoff << PAGE_SHIFT; 84774d2fad1SToshi Kani 84897d3d0f9SKirill A. Shutemov ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); 84997d3d0f9SKirill A. Shutemov if (ret) 85097d3d0f9SKirill A. Shutemov return ret; 8511854bc6eSWilliam Kucharski 85274d2fad1SToshi Kani return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); 85374d2fad1SToshi Kani } 85474d2fad1SToshi Kani EXPORT_SYMBOL_GPL(thp_get_unmapped_area); 85574d2fad1SToshi Kani 8562b740303SSouptick Joarder static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, 8572b740303SSouptick Joarder struct page *page, gfp_t gfp) 85871e3aac0SAndrea Arcangeli { 85982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 860cfe3236dSKefeng Wang struct folio *folio = page_folio(page); 86171e3aac0SAndrea Arcangeli pgtable_t pgtable; 86282b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 8632b740303SSouptick Joarder vm_fault_t ret = 0; 86471e3aac0SAndrea Arcangeli 865cfe3236dSKefeng Wang VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 86600501b53SJohannes Weiner 867cfe3236dSKefeng Wang if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) { 868cfe3236dSKefeng Wang folio_put(folio); 8696b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_FALLBACK); 87085b9f46eSDavid Rientjes count_vm_event(THP_FAULT_FALLBACK_CHARGE); 8716b251fc9SAndrea Arcangeli return VM_FAULT_FALLBACK; 8726b251fc9SAndrea Arcangeli } 873cfe3236dSKefeng Wang folio_throttle_swaprate(folio, gfp); 87471e3aac0SAndrea Arcangeli 8754cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 87600501b53SJohannes Weiner if (unlikely(!pgtable)) { 8776b31d595SMichal Hocko ret = VM_FAULT_OOM; 8786b31d595SMichal Hocko goto release; 87900501b53SJohannes Weiner } 88000501b53SJohannes Weiner 881c79b57e4SHuang Ying clear_huge_page(page, vmf->address, HPAGE_PMD_NR); 88252f37629SMinchan Kim /* 883cfe3236dSKefeng Wang * The memory barrier inside __folio_mark_uptodate makes sure that 88452f37629SMinchan Kim * clear_huge_page writes become visible before the set_pmd_at() 88552f37629SMinchan Kim * write. 88652f37629SMinchan Kim */ 887cfe3236dSKefeng Wang __folio_mark_uptodate(folio); 88871e3aac0SAndrea Arcangeli 88982b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 89082b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 8916b31d595SMichal Hocko goto unlock_release; 89271e3aac0SAndrea Arcangeli } else { 89371e3aac0SAndrea Arcangeli pmd_t entry; 8946b251fc9SAndrea Arcangeli 8956b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 8966b31d595SMichal Hocko if (ret) 8976b31d595SMichal Hocko goto unlock_release; 8986b31d595SMichal Hocko 8996b251fc9SAndrea Arcangeli /* Deliver the page fault to userland */ 9006b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 90182b0f8c3SJan Kara spin_unlock(vmf->ptl); 902cfe3236dSKefeng Wang folio_put(folio); 903bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 9048fd5eda4SMiaohe Lin ret = handle_userfault(vmf, VM_UFFD_MISSING); 9058fd5eda4SMiaohe Lin VM_BUG_ON(ret & VM_FAULT_FALLBACK); 9068fd5eda4SMiaohe Lin return ret; 9076b251fc9SAndrea Arcangeli } 9086b251fc9SAndrea Arcangeli 9093122359aSKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 910f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 911cfe3236dSKefeng Wang folio_add_new_anon_rmap(folio, vma, haddr); 912cfe3236dSKefeng Wang folio_add_lru_vma(folio, vma); 91382b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 91482b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 915fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 916bae473a4SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); 917c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 91882b0f8c3SJan Kara spin_unlock(vmf->ptl); 9196b251fc9SAndrea Arcangeli count_vm_event(THP_FAULT_ALLOC); 9209d82c694SJohannes Weiner count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); 92171e3aac0SAndrea Arcangeli } 92271e3aac0SAndrea Arcangeli 923aa2e878eSDavid Rientjes return 0; 9246b31d595SMichal Hocko unlock_release: 9256b31d595SMichal Hocko spin_unlock(vmf->ptl); 9266b31d595SMichal Hocko release: 9276b31d595SMichal Hocko if (pgtable) 9286b31d595SMichal Hocko pte_free(vma->vm_mm, pgtable); 929cfe3236dSKefeng Wang folio_put(folio); 9306b31d595SMichal Hocko return ret; 9316b31d595SMichal Hocko 93271e3aac0SAndrea Arcangeli } 93371e3aac0SAndrea Arcangeli 934444eb2a4SMel Gorman /* 93521440d7eSDavid Rientjes * always: directly stall for all thp allocations 93621440d7eSDavid Rientjes * defer: wake kswapd and fail if not immediately available 93721440d7eSDavid Rientjes * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise 93821440d7eSDavid Rientjes * fail if not immediately available 93921440d7eSDavid Rientjes * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately 94021440d7eSDavid Rientjes * available 94121440d7eSDavid Rientjes * never: never stall for any thp allocation 942444eb2a4SMel Gorman */ 943164cc4feSRik van Riel gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) 9440bbbc0b3SAndrea Arcangeli { 945164cc4feSRik van Riel const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); 94689c83fb5SMichal Hocko 947ac79f78dSDavid Rientjes /* Always do synchronous compaction */ 94821440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) 949a8282608SAndrea Arcangeli return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); 950ac79f78dSDavid Rientjes 951ac79f78dSDavid Rientjes /* Kick kcompactd and fail quickly */ 95221440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) 95319deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; 954ac79f78dSDavid Rientjes 955ac79f78dSDavid Rientjes /* Synchronous compaction if madvised, otherwise kick kcompactd */ 95621440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) 95719deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 95819deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 959ac79f78dSDavid Rientjes __GFP_KSWAPD_RECLAIM); 960ac79f78dSDavid Rientjes 961ac79f78dSDavid Rientjes /* Only do synchronous compaction if madvised */ 96221440d7eSDavid Rientjes if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) 96319deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT | 96419deb769SDavid Rientjes (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); 965ac79f78dSDavid Rientjes 96619deb769SDavid Rientjes return GFP_TRANSHUGE_LIGHT; 967444eb2a4SMel Gorman } 968444eb2a4SMel Gorman 969c4088ebdSKirill A. Shutemov /* Caller must hold page table lock. */ 9702efeb8daSMiaohe Lin static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, 97197ae1749SKirill A. Shutemov struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, 9725918d10aSKirill A. Shutemov struct page *zero_page) 973fc9fe822SKirill A. Shutemov { 974fc9fe822SKirill A. Shutemov pmd_t entry; 9757c414164SAndrew Morton if (!pmd_none(*pmd)) 9762efeb8daSMiaohe Lin return; 9775918d10aSKirill A. Shutemov entry = mk_pmd(zero_page, vma->vm_page_prot); 978fc9fe822SKirill A. Shutemov entry = pmd_mkhuge(entry); 9796b0b50b0SAneesh Kumar K.V pgtable_trans_huge_deposit(mm, pmd, pgtable); 980fc9fe822SKirill A. Shutemov set_pmd_at(mm, haddr, pmd, entry); 981c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 982fc9fe822SKirill A. Shutemov } 983fc9fe822SKirill A. Shutemov 9842b740303SSouptick Joarder vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) 98571e3aac0SAndrea Arcangeli { 98682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 987077fcf11SAneesh Kumar K.V gfp_t gfp; 988cb196ee1SMatthew Wilcox (Oracle) struct folio *folio; 98982b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 99071e3aac0SAndrea Arcangeli 9913485b883SRyan Roberts if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER)) 992c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 99371e3aac0SAndrea Arcangeli if (unlikely(anon_vma_prepare(vma))) 99471e3aac0SAndrea Arcangeli return VM_FAULT_OOM; 9954fa6893fSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 996d2081b2bSYang Shi 99782b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 998bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm) && 99979da5407SKirill A. Shutemov transparent_hugepage_use_zero_page()) { 100080371957SKirill A. Shutemov pgtable_t pgtable; 10015918d10aSKirill A. Shutemov struct page *zero_page; 10022b740303SSouptick Joarder vm_fault_t ret; 10034cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 100480371957SKirill A. Shutemov if (unlikely(!pgtable)) 100580371957SKirill A. Shutemov return VM_FAULT_OOM; 10066fcb52a5SAaron Lu zero_page = mm_get_huge_zero_page(vma->vm_mm); 10075918d10aSKirill A. Shutemov if (unlikely(!zero_page)) { 1008bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 100997ae1749SKirill A. Shutemov count_vm_event(THP_FAULT_FALLBACK); 1010c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 101197ae1749SKirill A. Shutemov } 101282b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 10136b251fc9SAndrea Arcangeli ret = 0; 101482b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 10156b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 10166b31d595SMichal Hocko if (ret) { 10176b31d595SMichal Hocko spin_unlock(vmf->ptl); 1018bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 10196b31d595SMichal Hocko } else if (userfaultfd_missing(vma)) { 102082b0f8c3SJan Kara spin_unlock(vmf->ptl); 1021bfe8cc1dSGerald Schaefer pte_free(vma->vm_mm, pgtable); 102282b0f8c3SJan Kara ret = handle_userfault(vmf, VM_UFFD_MISSING); 10236b251fc9SAndrea Arcangeli VM_BUG_ON(ret & VM_FAULT_FALLBACK); 10246b251fc9SAndrea Arcangeli } else { 1025bae473a4SKirill A. Shutemov set_huge_zero_page(pgtable, vma->vm_mm, vma, 102682b0f8c3SJan Kara haddr, vmf->pmd, zero_page); 1027fca40573SBibo Mao update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 102882b0f8c3SJan Kara spin_unlock(vmf->ptl); 10296b251fc9SAndrea Arcangeli } 1030bfe8cc1dSGerald Schaefer } else { 103182b0f8c3SJan Kara spin_unlock(vmf->ptl); 1032bae473a4SKirill A. Shutemov pte_free(vma->vm_mm, pgtable); 1033bfe8cc1dSGerald Schaefer } 10346b251fc9SAndrea Arcangeli return ret; 103580371957SKirill A. Shutemov } 1036164cc4feSRik van Riel gfp = vma_thp_gfp_mask(vma); 1037cb196ee1SMatthew Wilcox (Oracle) folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); 1038cb196ee1SMatthew Wilcox (Oracle) if (unlikely(!folio)) { 103981ab4201SAndi Kleen count_vm_event(THP_FAULT_FALLBACK); 1040c0292554SKirill A. Shutemov return VM_FAULT_FALLBACK; 104181ab4201SAndi Kleen } 1042cb196ee1SMatthew Wilcox (Oracle) return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); 104371e3aac0SAndrea Arcangeli } 104471e3aac0SAndrea Arcangeli 1045ae18d6dcSMatthew Wilcox static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 10463b6521f5SOliver O'Halloran pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, 10473b6521f5SOliver O'Halloran pgtable_t pgtable) 10485cad465dSMatthew Wilcox { 10495cad465dSMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 10505cad465dSMatthew Wilcox pmd_t entry; 10515cad465dSMatthew Wilcox spinlock_t *ptl; 10525cad465dSMatthew Wilcox 10535cad465dSMatthew Wilcox ptl = pmd_lock(mm, pmd); 1054c6f3c5eeSAneesh Kumar K.V if (!pmd_none(*pmd)) { 1055c6f3c5eeSAneesh Kumar K.V if (write) { 1056c6f3c5eeSAneesh Kumar K.V if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { 1057c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); 1058c6f3c5eeSAneesh Kumar K.V goto out_unlock; 1059c6f3c5eeSAneesh Kumar K.V } 1060c6f3c5eeSAneesh Kumar K.V entry = pmd_mkyoung(*pmd); 1061c6f3c5eeSAneesh Kumar K.V entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 1062c6f3c5eeSAneesh Kumar K.V if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) 1063c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pmd(vma, addr, pmd); 1064c6f3c5eeSAneesh Kumar K.V } 1065c6f3c5eeSAneesh Kumar K.V 1066c6f3c5eeSAneesh Kumar K.V goto out_unlock; 1067c6f3c5eeSAneesh Kumar K.V } 1068c6f3c5eeSAneesh Kumar K.V 1069f25748e3SDan Williams entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); 1070f25748e3SDan Williams if (pfn_t_devmap(pfn)) 1071f25748e3SDan Williams entry = pmd_mkdevmap(entry); 10725cad465dSMatthew Wilcox if (write) { 1073f55e1014SLinus Torvalds entry = pmd_mkyoung(pmd_mkdirty(entry)); 1074f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(entry, vma); 10755cad465dSMatthew Wilcox } 10763b6521f5SOliver O'Halloran 10773b6521f5SOliver O'Halloran if (pgtable) { 10783b6521f5SOliver O'Halloran pgtable_trans_huge_deposit(mm, pmd, pgtable); 1079c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 1080c6f3c5eeSAneesh Kumar K.V pgtable = NULL; 10813b6521f5SOliver O'Halloran } 10823b6521f5SOliver O'Halloran 10835cad465dSMatthew Wilcox set_pmd_at(mm, addr, pmd, entry); 10845cad465dSMatthew Wilcox update_mmu_cache_pmd(vma, addr, pmd); 1085c6f3c5eeSAneesh Kumar K.V 1086c6f3c5eeSAneesh Kumar K.V out_unlock: 10875cad465dSMatthew Wilcox spin_unlock(ptl); 1088c6f3c5eeSAneesh Kumar K.V if (pgtable) 1089c6f3c5eeSAneesh Kumar K.V pte_free(mm, pgtable); 10905cad465dSMatthew Wilcox } 10915cad465dSMatthew Wilcox 10929a9731b1SThomas Hellstrom (VMware) /** 10937b806d22SLorenzo Stoakes * vmf_insert_pfn_pmd - insert a pmd size pfn 10949a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 10959a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 10969a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 10979a9731b1SThomas Hellstrom (VMware) * 10987b806d22SLorenzo Stoakes * Insert a pmd size pfn. See vmf_insert_pfn() for additional info. 10999a9731b1SThomas Hellstrom (VMware) * 11009a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 11019a9731b1SThomas Hellstrom (VMware) */ 11027b806d22SLorenzo Stoakes vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) 11035cad465dSMatthew Wilcox { 1104fce86ff5SDan Williams unsigned long addr = vmf->address & PMD_MASK; 1105fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 11067b806d22SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 11073b6521f5SOliver O'Halloran pgtable_t pgtable = NULL; 1108fce86ff5SDan Williams 11095cad465dSMatthew Wilcox /* 11105cad465dSMatthew Wilcox * If we had pmd_special, we could avoid all these restrictions, 11115cad465dSMatthew Wilcox * but we need to be consistent with PTEs and architectures that 11125cad465dSMatthew Wilcox * can't support a 'special' bit. 11135cad465dSMatthew Wilcox */ 1114e1fb4a08SDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 1115e1fb4a08SDave Jiang !pfn_t_devmap(pfn)); 11165cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 11175cad465dSMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 11185cad465dSMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 11195cad465dSMatthew Wilcox 11205cad465dSMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 11215cad465dSMatthew Wilcox return VM_FAULT_SIGBUS; 1122308a047cSBorislav Petkov 11233b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) { 11244cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(vma->vm_mm); 11253b6521f5SOliver O'Halloran if (!pgtable) 11263b6521f5SOliver O'Halloran return VM_FAULT_OOM; 11273b6521f5SOliver O'Halloran } 11283b6521f5SOliver O'Halloran 1129308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 1130308a047cSBorislav Petkov 1131fce86ff5SDan Williams insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); 1132ae18d6dcSMatthew Wilcox return VM_FAULT_NOPAGE; 11335cad465dSMatthew Wilcox } 11347b806d22SLorenzo Stoakes EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); 11355cad465dSMatthew Wilcox 1136a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1137f55e1014SLinus Torvalds static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) 1138a00cc7d9SMatthew Wilcox { 1139f55e1014SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 1140a00cc7d9SMatthew Wilcox pud = pud_mkwrite(pud); 1141a00cc7d9SMatthew Wilcox return pud; 1142a00cc7d9SMatthew Wilcox } 1143a00cc7d9SMatthew Wilcox 1144a00cc7d9SMatthew Wilcox static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 11457b806d22SLorenzo Stoakes pud_t *pud, pfn_t pfn, bool write) 1146a00cc7d9SMatthew Wilcox { 1147a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 11487b806d22SLorenzo Stoakes pgprot_t prot = vma->vm_page_prot; 1149a00cc7d9SMatthew Wilcox pud_t entry; 1150a00cc7d9SMatthew Wilcox spinlock_t *ptl; 1151a00cc7d9SMatthew Wilcox 1152a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 1153c6f3c5eeSAneesh Kumar K.V if (!pud_none(*pud)) { 1154c6f3c5eeSAneesh Kumar K.V if (write) { 1155c6f3c5eeSAneesh Kumar K.V if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { 1156c6f3c5eeSAneesh Kumar K.V WARN_ON_ONCE(!is_huge_zero_pud(*pud)); 1157c6f3c5eeSAneesh Kumar K.V goto out_unlock; 1158c6f3c5eeSAneesh Kumar K.V } 1159c6f3c5eeSAneesh Kumar K.V entry = pud_mkyoung(*pud); 1160c6f3c5eeSAneesh Kumar K.V entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); 1161c6f3c5eeSAneesh Kumar K.V if (pudp_set_access_flags(vma, addr, pud, entry, 1)) 1162c6f3c5eeSAneesh Kumar K.V update_mmu_cache_pud(vma, addr, pud); 1163c6f3c5eeSAneesh Kumar K.V } 1164c6f3c5eeSAneesh Kumar K.V goto out_unlock; 1165c6f3c5eeSAneesh Kumar K.V } 1166c6f3c5eeSAneesh Kumar K.V 1167a00cc7d9SMatthew Wilcox entry = pud_mkhuge(pfn_t_pud(pfn, prot)); 1168a00cc7d9SMatthew Wilcox if (pfn_t_devmap(pfn)) 1169a00cc7d9SMatthew Wilcox entry = pud_mkdevmap(entry); 1170a00cc7d9SMatthew Wilcox if (write) { 1171f55e1014SLinus Torvalds entry = pud_mkyoung(pud_mkdirty(entry)); 1172f55e1014SLinus Torvalds entry = maybe_pud_mkwrite(entry, vma); 1173a00cc7d9SMatthew Wilcox } 1174a00cc7d9SMatthew Wilcox set_pud_at(mm, addr, pud, entry); 1175a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1176c6f3c5eeSAneesh Kumar K.V 1177c6f3c5eeSAneesh Kumar K.V out_unlock: 1178a00cc7d9SMatthew Wilcox spin_unlock(ptl); 1179a00cc7d9SMatthew Wilcox } 1180a00cc7d9SMatthew Wilcox 11819a9731b1SThomas Hellstrom (VMware) /** 11827b806d22SLorenzo Stoakes * vmf_insert_pfn_pud - insert a pud size pfn 11839a9731b1SThomas Hellstrom (VMware) * @vmf: Structure describing the fault 11849a9731b1SThomas Hellstrom (VMware) * @pfn: pfn to insert 11859a9731b1SThomas Hellstrom (VMware) * @write: whether it's a write fault 11869a9731b1SThomas Hellstrom (VMware) * 11877b806d22SLorenzo Stoakes * Insert a pud size pfn. See vmf_insert_pfn() for additional info. 11889a9731b1SThomas Hellstrom (VMware) * 11899a9731b1SThomas Hellstrom (VMware) * Return: vm_fault_t value. 11909a9731b1SThomas Hellstrom (VMware) */ 11917b806d22SLorenzo Stoakes vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) 1192a00cc7d9SMatthew Wilcox { 1193fce86ff5SDan Williams unsigned long addr = vmf->address & PUD_MASK; 1194fce86ff5SDan Williams struct vm_area_struct *vma = vmf->vma; 11957b806d22SLorenzo Stoakes pgprot_t pgprot = vma->vm_page_prot; 1196fce86ff5SDan Williams 1197a00cc7d9SMatthew Wilcox /* 1198a00cc7d9SMatthew Wilcox * If we had pud_special, we could avoid all these restrictions, 1199a00cc7d9SMatthew Wilcox * but we need to be consistent with PTEs and architectures that 1200a00cc7d9SMatthew Wilcox * can't support a 'special' bit. 1201a00cc7d9SMatthew Wilcox */ 120262ec0d8cSDave Jiang BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && 120362ec0d8cSDave Jiang !pfn_t_devmap(pfn)); 1204a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 1205a00cc7d9SMatthew Wilcox (VM_PFNMAP|VM_MIXEDMAP)); 1206a00cc7d9SMatthew Wilcox BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 1207a00cc7d9SMatthew Wilcox 1208a00cc7d9SMatthew Wilcox if (addr < vma->vm_start || addr >= vma->vm_end) 1209a00cc7d9SMatthew Wilcox return VM_FAULT_SIGBUS; 1210a00cc7d9SMatthew Wilcox 1211a00cc7d9SMatthew Wilcox track_pfn_insert(vma, &pgprot, pfn); 1212a00cc7d9SMatthew Wilcox 12137b806d22SLorenzo Stoakes insert_pfn_pud(vma, addr, vmf->pud, pfn, write); 1214a00cc7d9SMatthew Wilcox return VM_FAULT_NOPAGE; 1215a00cc7d9SMatthew Wilcox } 12167b806d22SLorenzo Stoakes EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); 1217a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1218a00cc7d9SMatthew Wilcox 12193565fce3SDan Williams static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, 1220a69e4717SMiaohe Lin pmd_t *pmd, bool write) 12213565fce3SDan Williams { 12223565fce3SDan Williams pmd_t _pmd; 12233565fce3SDan Williams 1224a8f97366SKirill A. Shutemov _pmd = pmd_mkyoung(*pmd); 1225a69e4717SMiaohe Lin if (write) 1226a8f97366SKirill A. Shutemov _pmd = pmd_mkdirty(_pmd); 12273565fce3SDan Williams if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, 1228a69e4717SMiaohe Lin pmd, _pmd, write)) 12293565fce3SDan Williams update_mmu_cache_pmd(vma, addr, pmd); 12303565fce3SDan Williams } 12313565fce3SDan Williams 12323565fce3SDan Williams struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, 1233df06b37fSKeith Busch pmd_t *pmd, int flags, struct dev_pagemap **pgmap) 12343565fce3SDan Williams { 12353565fce3SDan Williams unsigned long pfn = pmd_pfn(*pmd); 12363565fce3SDan Williams struct mm_struct *mm = vma->vm_mm; 12373565fce3SDan Williams struct page *page; 12380f089235SLogan Gunthorpe int ret; 12393565fce3SDan Williams 12403565fce3SDan Williams assert_spin_locked(pmd_lockptr(mm, pmd)); 12413565fce3SDan Williams 1242f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pmd_write(*pmd)) 12433565fce3SDan Williams return NULL; 12443565fce3SDan Williams 12453565fce3SDan Williams if (pmd_present(*pmd) && pmd_devmap(*pmd)) 12463565fce3SDan Williams /* pass */; 12473565fce3SDan Williams else 12483565fce3SDan Williams return NULL; 12493565fce3SDan Williams 12503565fce3SDan Williams if (flags & FOLL_TOUCH) 1251a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 12523565fce3SDan Williams 12533565fce3SDan Williams /* 12543565fce3SDan Williams * device mapped pages can only be returned if the 12553565fce3SDan Williams * caller will manage the page reference count. 12563565fce3SDan Williams */ 12573faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 12583565fce3SDan Williams return ERR_PTR(-EEXIST); 12593565fce3SDan Williams 12603565fce3SDan Williams pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; 1261df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1262df06b37fSKeith Busch if (!*pgmap) 12633565fce3SDan Williams return ERR_PTR(-EFAULT); 12643565fce3SDan Williams page = pfn_to_page(pfn); 12650f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 12660f089235SLogan Gunthorpe if (ret) 12670f089235SLogan Gunthorpe page = ERR_PTR(ret); 12683565fce3SDan Williams 12693565fce3SDan Williams return page; 12703565fce3SDan Williams } 12713565fce3SDan Williams 127271e3aac0SAndrea Arcangeli int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, 127371e3aac0SAndrea Arcangeli pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, 12748f34f1eaSPeter Xu struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) 127571e3aac0SAndrea Arcangeli { 1276c4088ebdSKirill A. Shutemov spinlock_t *dst_ptl, *src_ptl; 127771e3aac0SAndrea Arcangeli struct page *src_page; 127871e3aac0SAndrea Arcangeli pmd_t pmd; 127912c9d70bSMatthew Wilcox pgtable_t pgtable = NULL; 1280628d47ceSKirill A. Shutemov int ret = -ENOMEM; 128171e3aac0SAndrea Arcangeli 1282628d47ceSKirill A. Shutemov /* Skip if can be re-fill on fault */ 12838f34f1eaSPeter Xu if (!vma_is_anonymous(dst_vma)) 1284628d47ceSKirill A. Shutemov return 0; 1285628d47ceSKirill A. Shutemov 12864cf58924SJoel Fernandes (Google) pgtable = pte_alloc_one(dst_mm); 128771e3aac0SAndrea Arcangeli if (unlikely(!pgtable)) 128871e3aac0SAndrea Arcangeli goto out; 128971e3aac0SAndrea Arcangeli 1290c4088ebdSKirill A. Shutemov dst_ptl = pmd_lock(dst_mm, dst_pmd); 1291c4088ebdSKirill A. Shutemov src_ptl = pmd_lockptr(src_mm, src_pmd); 1292c4088ebdSKirill A. Shutemov spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 129371e3aac0SAndrea Arcangeli 129471e3aac0SAndrea Arcangeli ret = -EAGAIN; 129571e3aac0SAndrea Arcangeli pmd = *src_pmd; 129684c3fc4eSZi Yan 129784c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 129884c3fc4eSZi Yan if (unlikely(is_swap_pmd(pmd))) { 129984c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(pmd); 130084c3fc4eSZi Yan 130184c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(pmd)); 13026c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) { 13034dd845b5SAlistair Popple entry = make_readable_migration_entry( 13044dd845b5SAlistair Popple swp_offset(entry)); 130584c3fc4eSZi Yan pmd = swp_entry_to_pmd(entry); 1306ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*src_pmd)) 1307ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 13088f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*src_pmd)) 13098f34f1eaSPeter Xu pmd = pmd_swp_mkuffd_wp(pmd); 131084c3fc4eSZi Yan set_pmd_at(src_mm, addr, src_pmd, pmd); 131184c3fc4eSZi Yan } 1312dd8a67f9SZi Yan add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 1313af5b0f6aSKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 1314dd8a67f9SZi Yan pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 13158f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 13168f34f1eaSPeter Xu pmd = pmd_swp_clear_uffd_wp(pmd); 131784c3fc4eSZi Yan set_pmd_at(dst_mm, addr, dst_pmd, pmd); 131884c3fc4eSZi Yan ret = 0; 131984c3fc4eSZi Yan goto out_unlock; 132084c3fc4eSZi Yan } 132184c3fc4eSZi Yan #endif 132284c3fc4eSZi Yan 1323628d47ceSKirill A. Shutemov if (unlikely(!pmd_trans_huge(pmd))) { 132471e3aac0SAndrea Arcangeli pte_free(dst_mm, pgtable); 132571e3aac0SAndrea Arcangeli goto out_unlock; 132671e3aac0SAndrea Arcangeli } 1327fc9fe822SKirill A. Shutemov /* 1328c4088ebdSKirill A. Shutemov * When page table lock is held, the huge zero pmd should not be 1329fc9fe822SKirill A. Shutemov * under splitting since we don't split the page itself, only pmd to 1330fc9fe822SKirill A. Shutemov * a page table. 1331fc9fe822SKirill A. Shutemov */ 1332fc9fe822SKirill A. Shutemov if (is_huge_zero_pmd(pmd)) { 133397ae1749SKirill A. Shutemov /* 133497ae1749SKirill A. Shutemov * get_huge_zero_page() will never allocate a new page here, 133597ae1749SKirill A. Shutemov * since we already have a zero page to copy. It just takes a 133697ae1749SKirill A. Shutemov * reference. 133797ae1749SKirill A. Shutemov */ 13385fc7a5f6SPeter Xu mm_get_huge_zero_page(dst_mm); 13395fc7a5f6SPeter Xu goto out_zero_page; 1340fc9fe822SKirill A. Shutemov } 1341de466bd6SMel Gorman 134271e3aac0SAndrea Arcangeli src_page = pmd_page(pmd); 1343309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(src_page), src_page); 1344d042035eSPeter Xu 1345fb3d824dSDavid Hildenbrand get_page(src_page); 1346fb3d824dSDavid Hildenbrand if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { 1347fb3d824dSDavid Hildenbrand /* Page maybe pinned: split and retry the fault on PTEs. */ 1348fb3d824dSDavid Hildenbrand put_page(src_page); 1349d042035eSPeter Xu pte_free(dst_mm, pgtable); 1350d042035eSPeter Xu spin_unlock(src_ptl); 1351d042035eSPeter Xu spin_unlock(dst_ptl); 13528f34f1eaSPeter Xu __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); 1353d042035eSPeter Xu return -EAGAIN; 1354d042035eSPeter Xu } 135571e3aac0SAndrea Arcangeli add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); 13565fc7a5f6SPeter Xu out_zero_page: 1357c4812909SKirill A. Shutemov mm_inc_nr_ptes(dst_mm); 13585c7fb56eSDan Williams pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); 135971e3aac0SAndrea Arcangeli pmdp_set_wrprotect(src_mm, addr, src_pmd); 13608f34f1eaSPeter Xu if (!userfaultfd_wp(dst_vma)) 13618f34f1eaSPeter Xu pmd = pmd_clear_uffd_wp(pmd); 136271e3aac0SAndrea Arcangeli pmd = pmd_mkold(pmd_wrprotect(pmd)); 136371e3aac0SAndrea Arcangeli set_pmd_at(dst_mm, addr, dst_pmd, pmd); 136471e3aac0SAndrea Arcangeli 136571e3aac0SAndrea Arcangeli ret = 0; 136671e3aac0SAndrea Arcangeli out_unlock: 1367c4088ebdSKirill A. Shutemov spin_unlock(src_ptl); 1368c4088ebdSKirill A. Shutemov spin_unlock(dst_ptl); 136971e3aac0SAndrea Arcangeli out: 137071e3aac0SAndrea Arcangeli return ret; 137171e3aac0SAndrea Arcangeli } 137271e3aac0SAndrea Arcangeli 1373a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 1374a00cc7d9SMatthew Wilcox static void touch_pud(struct vm_area_struct *vma, unsigned long addr, 13755fe653e9SMiaohe Lin pud_t *pud, bool write) 1376a00cc7d9SMatthew Wilcox { 1377a00cc7d9SMatthew Wilcox pud_t _pud; 1378a00cc7d9SMatthew Wilcox 1379a8f97366SKirill A. Shutemov _pud = pud_mkyoung(*pud); 13805fe653e9SMiaohe Lin if (write) 1381a8f97366SKirill A. Shutemov _pud = pud_mkdirty(_pud); 1382a00cc7d9SMatthew Wilcox if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, 13835fe653e9SMiaohe Lin pud, _pud, write)) 1384a00cc7d9SMatthew Wilcox update_mmu_cache_pud(vma, addr, pud); 1385a00cc7d9SMatthew Wilcox } 1386a00cc7d9SMatthew Wilcox 1387a00cc7d9SMatthew Wilcox struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, 1388df06b37fSKeith Busch pud_t *pud, int flags, struct dev_pagemap **pgmap) 1389a00cc7d9SMatthew Wilcox { 1390a00cc7d9SMatthew Wilcox unsigned long pfn = pud_pfn(*pud); 1391a00cc7d9SMatthew Wilcox struct mm_struct *mm = vma->vm_mm; 1392a00cc7d9SMatthew Wilcox struct page *page; 13930f089235SLogan Gunthorpe int ret; 1394a00cc7d9SMatthew Wilcox 1395a00cc7d9SMatthew Wilcox assert_spin_locked(pud_lockptr(mm, pud)); 1396a00cc7d9SMatthew Wilcox 1397f6f37321SLinus Torvalds if (flags & FOLL_WRITE && !pud_write(*pud)) 1398a00cc7d9SMatthew Wilcox return NULL; 1399a00cc7d9SMatthew Wilcox 1400a00cc7d9SMatthew Wilcox if (pud_present(*pud) && pud_devmap(*pud)) 1401a00cc7d9SMatthew Wilcox /* pass */; 1402a00cc7d9SMatthew Wilcox else 1403a00cc7d9SMatthew Wilcox return NULL; 1404a00cc7d9SMatthew Wilcox 1405a00cc7d9SMatthew Wilcox if (flags & FOLL_TOUCH) 14065fe653e9SMiaohe Lin touch_pud(vma, addr, pud, flags & FOLL_WRITE); 1407a00cc7d9SMatthew Wilcox 1408a00cc7d9SMatthew Wilcox /* 1409a00cc7d9SMatthew Wilcox * device mapped pages can only be returned if the 1410a00cc7d9SMatthew Wilcox * caller will manage the page reference count. 14113faa52c0SJohn Hubbard * 14123faa52c0SJohn Hubbard * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: 1413a00cc7d9SMatthew Wilcox */ 14143faa52c0SJohn Hubbard if (!(flags & (FOLL_GET | FOLL_PIN))) 1415a00cc7d9SMatthew Wilcox return ERR_PTR(-EEXIST); 1416a00cc7d9SMatthew Wilcox 1417a00cc7d9SMatthew Wilcox pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; 1418df06b37fSKeith Busch *pgmap = get_dev_pagemap(pfn, *pgmap); 1419df06b37fSKeith Busch if (!*pgmap) 1420a00cc7d9SMatthew Wilcox return ERR_PTR(-EFAULT); 1421a00cc7d9SMatthew Wilcox page = pfn_to_page(pfn); 14220f089235SLogan Gunthorpe 14230f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 14240f089235SLogan Gunthorpe if (ret) 14250f089235SLogan Gunthorpe page = ERR_PTR(ret); 1426a00cc7d9SMatthew Wilcox 1427a00cc7d9SMatthew Wilcox return page; 1428a00cc7d9SMatthew Wilcox } 1429a00cc7d9SMatthew Wilcox 1430a00cc7d9SMatthew Wilcox int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1431a00cc7d9SMatthew Wilcox pud_t *dst_pud, pud_t *src_pud, unsigned long addr, 1432a00cc7d9SMatthew Wilcox struct vm_area_struct *vma) 1433a00cc7d9SMatthew Wilcox { 1434a00cc7d9SMatthew Wilcox spinlock_t *dst_ptl, *src_ptl; 1435a00cc7d9SMatthew Wilcox pud_t pud; 1436a00cc7d9SMatthew Wilcox int ret; 1437a00cc7d9SMatthew Wilcox 1438a00cc7d9SMatthew Wilcox dst_ptl = pud_lock(dst_mm, dst_pud); 1439a00cc7d9SMatthew Wilcox src_ptl = pud_lockptr(src_mm, src_pud); 1440a00cc7d9SMatthew Wilcox spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1441a00cc7d9SMatthew Wilcox 1442a00cc7d9SMatthew Wilcox ret = -EAGAIN; 1443a00cc7d9SMatthew Wilcox pud = *src_pud; 1444a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) 1445a00cc7d9SMatthew Wilcox goto out_unlock; 1446a00cc7d9SMatthew Wilcox 1447a00cc7d9SMatthew Wilcox /* 1448a00cc7d9SMatthew Wilcox * When page table lock is held, the huge zero pud should not be 1449a00cc7d9SMatthew Wilcox * under splitting since we don't split the page itself, only pud to 1450a00cc7d9SMatthew Wilcox * a page table. 1451a00cc7d9SMatthew Wilcox */ 1452a00cc7d9SMatthew Wilcox if (is_huge_zero_pud(pud)) { 1453a00cc7d9SMatthew Wilcox /* No huge zero pud yet */ 1454a00cc7d9SMatthew Wilcox } 1455a00cc7d9SMatthew Wilcox 1456fb3d824dSDavid Hildenbrand /* 1457fb3d824dSDavid Hildenbrand * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() 1458fb3d824dSDavid Hildenbrand * and split if duplicating fails. 1459fb3d824dSDavid Hildenbrand */ 1460a00cc7d9SMatthew Wilcox pudp_set_wrprotect(src_mm, addr, src_pud); 1461a00cc7d9SMatthew Wilcox pud = pud_mkold(pud_wrprotect(pud)); 1462a00cc7d9SMatthew Wilcox set_pud_at(dst_mm, addr, dst_pud, pud); 1463a00cc7d9SMatthew Wilcox 1464a00cc7d9SMatthew Wilcox ret = 0; 1465a00cc7d9SMatthew Wilcox out_unlock: 1466a00cc7d9SMatthew Wilcox spin_unlock(src_ptl); 1467a00cc7d9SMatthew Wilcox spin_unlock(dst_ptl); 1468a00cc7d9SMatthew Wilcox return ret; 1469a00cc7d9SMatthew Wilcox } 1470a00cc7d9SMatthew Wilcox 1471a00cc7d9SMatthew Wilcox void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) 1472a00cc7d9SMatthew Wilcox { 1473a00cc7d9SMatthew Wilcox bool write = vmf->flags & FAULT_FLAG_WRITE; 1474a00cc7d9SMatthew Wilcox 1475a00cc7d9SMatthew Wilcox vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); 1476a00cc7d9SMatthew Wilcox if (unlikely(!pud_same(*vmf->pud, orig_pud))) 1477a00cc7d9SMatthew Wilcox goto unlock; 1478a00cc7d9SMatthew Wilcox 14795fe653e9SMiaohe Lin touch_pud(vmf->vma, vmf->address, vmf->pud, write); 1480a00cc7d9SMatthew Wilcox unlock: 1481a00cc7d9SMatthew Wilcox spin_unlock(vmf->ptl); 1482a00cc7d9SMatthew Wilcox } 1483a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 1484a00cc7d9SMatthew Wilcox 14855db4f15cSYang Shi void huge_pmd_set_accessed(struct vm_fault *vmf) 1486a1dd450bSWill Deacon { 148720f664aaSMinchan Kim bool write = vmf->flags & FAULT_FLAG_WRITE; 1488a1dd450bSWill Deacon 148982b0f8c3SJan Kara vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 1490a69e4717SMiaohe Lin if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) 1491a1dd450bSWill Deacon goto unlock; 1492a1dd450bSWill Deacon 1493a69e4717SMiaohe Lin touch_pmd(vmf->vma, vmf->address, vmf->pmd, write); 1494a1dd450bSWill Deacon 1495a1dd450bSWill Deacon unlock: 149682b0f8c3SJan Kara spin_unlock(vmf->ptl); 1497a1dd450bSWill Deacon } 1498a1dd450bSWill Deacon 14995db4f15cSYang Shi vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) 150071e3aac0SAndrea Arcangeli { 1501c89357e2SDavid Hildenbrand const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; 150282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 15032fad3d14SMatthew Wilcox (Oracle) struct folio *folio; 15043917c802SKirill A. Shutemov struct page *page; 150582b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 15065db4f15cSYang Shi pmd_t orig_pmd = vmf->orig_pmd; 150771e3aac0SAndrea Arcangeli 150882b0f8c3SJan Kara vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); 150981d1b09cSSasha Levin VM_BUG_ON_VMA(!vma->anon_vma, vma); 15103917c802SKirill A. Shutemov 151193b4796dSKirill A. Shutemov if (is_huge_zero_pmd(orig_pmd)) 15123917c802SKirill A. Shutemov goto fallback; 15133917c802SKirill A. Shutemov 151482b0f8c3SJan Kara spin_lock(vmf->ptl); 15153917c802SKirill A. Shutemov 15163917c802SKirill A. Shutemov if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 15173917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 15183917c802SKirill A. Shutemov return 0; 15193917c802SKirill A. Shutemov } 152071e3aac0SAndrea Arcangeli 152171e3aac0SAndrea Arcangeli page = pmd_page(orig_pmd); 15222fad3d14SMatthew Wilcox (Oracle) folio = page_folio(page); 1523f6004e73SMiaohe Lin VM_BUG_ON_PAGE(!PageHead(page), page); 15243917c802SKirill A. Shutemov 15256c287605SDavid Hildenbrand /* Early check when only holding the PT lock. */ 15266c287605SDavid Hildenbrand if (PageAnonExclusive(page)) 15276c287605SDavid Hildenbrand goto reuse; 15286c287605SDavid Hildenbrand 15292fad3d14SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) { 15302fad3d14SMatthew Wilcox (Oracle) folio_get(folio); 1531ba3c4ce6SHuang Ying spin_unlock(vmf->ptl); 15322fad3d14SMatthew Wilcox (Oracle) folio_lock(folio); 1533ba3c4ce6SHuang Ying spin_lock(vmf->ptl); 1534ba3c4ce6SHuang Ying if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { 15353917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 15362fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 15372fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 15383917c802SKirill A. Shutemov return 0; 1539ba3c4ce6SHuang Ying } 15402fad3d14SMatthew Wilcox (Oracle) folio_put(folio); 1541ba3c4ce6SHuang Ying } 15423917c802SKirill A. Shutemov 15436c287605SDavid Hildenbrand /* Recheck after temporarily dropping the PT lock. */ 15446c287605SDavid Hildenbrand if (PageAnonExclusive(page)) { 15452fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 15466c287605SDavid Hildenbrand goto reuse; 15476c287605SDavid Hildenbrand } 15486c287605SDavid Hildenbrand 15493917c802SKirill A. Shutemov /* 15502fad3d14SMatthew Wilcox (Oracle) * See do_wp_page(): we can only reuse the folio exclusively if 15512fad3d14SMatthew Wilcox (Oracle) * there are no additional references. Note that we always drain 15521fec6890SMatthew Wilcox (Oracle) * the LRU cache immediately after adding a THP. 15533917c802SKirill A. Shutemov */ 15542fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) > 15552fad3d14SMatthew Wilcox (Oracle) 1 + folio_test_swapcache(folio) * folio_nr_pages(folio)) 15563bff7e3fSDavid Hildenbrand goto unlock_fallback; 15572fad3d14SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 15582fad3d14SMatthew Wilcox (Oracle) folio_free_swap(folio); 15592fad3d14SMatthew Wilcox (Oracle) if (folio_ref_count(folio) == 1) { 156071e3aac0SAndrea Arcangeli pmd_t entry; 15616c54dc6cSDavid Hildenbrand 156206968625SDavid Hildenbrand folio_move_anon_rmap(folio, vma); 15635ca43289SDavid Hildenbrand SetPageAnonExclusive(page); 15642fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 15656c287605SDavid Hildenbrand reuse: 1566c89357e2SDavid Hildenbrand if (unlikely(unshare)) { 1567c89357e2SDavid Hildenbrand spin_unlock(vmf->ptl); 1568c89357e2SDavid Hildenbrand return 0; 1569c89357e2SDavid Hildenbrand } 157071e3aac0SAndrea Arcangeli entry = pmd_mkyoung(orig_pmd); 1571f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 157282b0f8c3SJan Kara if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) 157382b0f8c3SJan Kara update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 15743917c802SKirill A. Shutemov spin_unlock(vmf->ptl); 1575cb8d8633SDavid Hildenbrand return 0; 157671e3aac0SAndrea Arcangeli } 15773917c802SKirill A. Shutemov 15783bff7e3fSDavid Hildenbrand unlock_fallback: 15792fad3d14SMatthew Wilcox (Oracle) folio_unlock(folio); 158082b0f8c3SJan Kara spin_unlock(vmf->ptl); 15813917c802SKirill A. Shutemov fallback: 15823917c802SKirill A. Shutemov __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); 15833917c802SKirill A. Shutemov return VM_FAULT_FALLBACK; 158471e3aac0SAndrea Arcangeli } 158571e3aac0SAndrea Arcangeli 1586c27f479eSDavid Hildenbrand static inline bool can_change_pmd_writable(struct vm_area_struct *vma, 1587c27f479eSDavid Hildenbrand unsigned long addr, pmd_t pmd) 1588c27f479eSDavid Hildenbrand { 1589c27f479eSDavid Hildenbrand struct page *page; 1590c27f479eSDavid Hildenbrand 1591c27f479eSDavid Hildenbrand if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) 1592c27f479eSDavid Hildenbrand return false; 1593c27f479eSDavid Hildenbrand 1594c27f479eSDavid Hildenbrand /* Don't touch entries that are not even readable (NUMA hinting). */ 1595c27f479eSDavid Hildenbrand if (pmd_protnone(pmd)) 1596c27f479eSDavid Hildenbrand return false; 1597c27f479eSDavid Hildenbrand 1598c27f479eSDavid Hildenbrand /* Do we need write faults for softdirty tracking? */ 1599c27f479eSDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 1600c27f479eSDavid Hildenbrand return false; 1601c27f479eSDavid Hildenbrand 1602c27f479eSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 1603c27f479eSDavid Hildenbrand if (userfaultfd_huge_pmd_wp(vma, pmd)) 1604c27f479eSDavid Hildenbrand return false; 1605c27f479eSDavid Hildenbrand 1606c27f479eSDavid Hildenbrand if (!(vma->vm_flags & VM_SHARED)) { 1607c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1608c27f479eSDavid Hildenbrand page = vm_normal_page_pmd(vma, addr, pmd); 1609c27f479eSDavid Hildenbrand return page && PageAnon(page) && PageAnonExclusive(page); 1610c27f479eSDavid Hildenbrand } 1611c27f479eSDavid Hildenbrand 1612c27f479eSDavid Hildenbrand /* See can_change_pte_writable(). */ 1613c27f479eSDavid Hildenbrand return pmd_dirty(pmd); 1614c27f479eSDavid Hildenbrand } 1615c27f479eSDavid Hildenbrand 16165535be30SDavid Hildenbrand /* FOLL_FORCE can write to even unwritable PMDs in COW mappings. */ 16175535be30SDavid Hildenbrand static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, 16185535be30SDavid Hildenbrand struct vm_area_struct *vma, 16195535be30SDavid Hildenbrand unsigned int flags) 16208310d48bSKeno Fischer { 16215535be30SDavid Hildenbrand /* If the pmd is writable, we can write to the page. */ 16225535be30SDavid Hildenbrand if (pmd_write(pmd)) 16235535be30SDavid Hildenbrand return true; 16245535be30SDavid Hildenbrand 16255535be30SDavid Hildenbrand /* Maybe FOLL_FORCE is set to override it? */ 16265535be30SDavid Hildenbrand if (!(flags & FOLL_FORCE)) 16275535be30SDavid Hildenbrand return false; 16285535be30SDavid Hildenbrand 16295535be30SDavid Hildenbrand /* But FOLL_FORCE has no effect on shared mappings */ 16305535be30SDavid Hildenbrand if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED)) 16315535be30SDavid Hildenbrand return false; 16325535be30SDavid Hildenbrand 16335535be30SDavid Hildenbrand /* ... or read-only private ones */ 16345535be30SDavid Hildenbrand if (!(vma->vm_flags & VM_MAYWRITE)) 16355535be30SDavid Hildenbrand return false; 16365535be30SDavid Hildenbrand 16375535be30SDavid Hildenbrand /* ... or already writable ones that just need to take a write fault */ 16385535be30SDavid Hildenbrand if (vma->vm_flags & VM_WRITE) 16395535be30SDavid Hildenbrand return false; 16405535be30SDavid Hildenbrand 16415535be30SDavid Hildenbrand /* 16425535be30SDavid Hildenbrand * See can_change_pte_writable(): we broke COW and could map the page 16435535be30SDavid Hildenbrand * writable if we have an exclusive anonymous page ... 16445535be30SDavid Hildenbrand */ 16455535be30SDavid Hildenbrand if (!page || !PageAnon(page) || !PageAnonExclusive(page)) 16465535be30SDavid Hildenbrand return false; 16475535be30SDavid Hildenbrand 16485535be30SDavid Hildenbrand /* ... and a write-fault isn't required for other reasons. */ 16495535be30SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) 16505535be30SDavid Hildenbrand return false; 16515535be30SDavid Hildenbrand return !userfaultfd_huge_pmd_wp(vma, pmd); 16528310d48bSKeno Fischer } 16538310d48bSKeno Fischer 1654b676b293SDavid Rientjes struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, 165571e3aac0SAndrea Arcangeli unsigned long addr, 165671e3aac0SAndrea Arcangeli pmd_t *pmd, 165771e3aac0SAndrea Arcangeli unsigned int flags) 165871e3aac0SAndrea Arcangeli { 1659b676b293SDavid Rientjes struct mm_struct *mm = vma->vm_mm; 16605535be30SDavid Hildenbrand struct page *page; 16610f089235SLogan Gunthorpe int ret; 166271e3aac0SAndrea Arcangeli 1663c4088ebdSKirill A. Shutemov assert_spin_locked(pmd_lockptr(mm, pmd)); 166471e3aac0SAndrea Arcangeli 16655535be30SDavid Hildenbrand page = pmd_page(*pmd); 16665535be30SDavid Hildenbrand VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); 16675535be30SDavid Hildenbrand 16685535be30SDavid Hildenbrand if ((flags & FOLL_WRITE) && 16695535be30SDavid Hildenbrand !can_follow_write_pmd(*pmd, page, vma, flags)) 16705535be30SDavid Hildenbrand return NULL; 167171e3aac0SAndrea Arcangeli 167285facf25SKirill A. Shutemov /* Avoid dumping huge zero page */ 167385facf25SKirill A. Shutemov if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) 167485facf25SKirill A. Shutemov return ERR_PTR(-EFAULT); 167585facf25SKirill A. Shutemov 1676d74943a2SDavid Hildenbrand if (pmd_protnone(*pmd) && !gup_can_follow_protnone(vma, flags)) 16775535be30SDavid Hildenbrand return NULL; 16783faa52c0SJohn Hubbard 167984209e87SDavid Hildenbrand if (!pmd_write(*pmd) && gup_must_unshare(vma, flags, page)) 1680a7f22660SDavid Hildenbrand return ERR_PTR(-EMLINK); 1681a7f22660SDavid Hildenbrand 1682b6a2619cSDavid Hildenbrand VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && 1683b6a2619cSDavid Hildenbrand !PageAnonExclusive(page), page); 1684b6a2619cSDavid Hildenbrand 16850f089235SLogan Gunthorpe ret = try_grab_page(page, flags); 16860f089235SLogan Gunthorpe if (ret) 16870f089235SLogan Gunthorpe return ERR_PTR(ret); 16883faa52c0SJohn Hubbard 16893565fce3SDan Williams if (flags & FOLL_TOUCH) 1690a69e4717SMiaohe Lin touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); 16913faa52c0SJohn Hubbard 169271e3aac0SAndrea Arcangeli page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; 1693ca120cf6SDan Williams VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); 169471e3aac0SAndrea Arcangeli 169571e3aac0SAndrea Arcangeli return page; 169671e3aac0SAndrea Arcangeli } 169771e3aac0SAndrea Arcangeli 1698d10e63f2SMel Gorman /* NUMA hinting page fault entry point for trans huge pmds */ 16995db4f15cSYang Shi vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) 1700d10e63f2SMel Gorman { 170182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 1702c5b5a3ddSYang Shi pmd_t oldpmd = vmf->orig_pmd; 1703c5b5a3ddSYang Shi pmd_t pmd; 1704667ffc31SKefeng Wang struct folio *folio; 170582b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 1706667ffc31SKefeng Wang int nid = NUMA_NO_NODE; 170733024536SHuang Ying int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); 17086a56ccbcSDavid Hildenbrand bool migrated = false, writable = false; 17096688cc05SPeter Zijlstra int flags = 0; 1710d10e63f2SMel Gorman 171182b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1712c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 171382b0f8c3SJan Kara spin_unlock(vmf->ptl); 1714de466bd6SMel Gorman goto out; 1715de466bd6SMel Gorman } 1716de466bd6SMel Gorman 1717c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 17186a56ccbcSDavid Hildenbrand 17196a56ccbcSDavid Hildenbrand /* 17206a56ccbcSDavid Hildenbrand * Detect now whether the PMD could be writable; this information 17216a56ccbcSDavid Hildenbrand * is only valid while holding the PT lock. 17226a56ccbcSDavid Hildenbrand */ 17236a56ccbcSDavid Hildenbrand writable = pmd_write(pmd); 17246a56ccbcSDavid Hildenbrand if (!writable && vma_wants_manual_pte_write_upgrade(vma) && 17256a56ccbcSDavid Hildenbrand can_change_pmd_writable(vma, vmf->address, pmd)) 17266a56ccbcSDavid Hildenbrand writable = true; 17276a56ccbcSDavid Hildenbrand 1728667ffc31SKefeng Wang folio = vm_normal_folio_pmd(vma, haddr, pmd); 1729667ffc31SKefeng Wang if (!folio) 1730c5b5a3ddSYang Shi goto out_map; 1731c5b5a3ddSYang Shi 1732c5b5a3ddSYang Shi /* See similar comment in do_numa_page for explanation */ 17336a56ccbcSDavid Hildenbrand if (!writable) 1734c5b5a3ddSYang Shi flags |= TNF_NO_GROUP; 1735c5b5a3ddSYang Shi 1736667ffc31SKefeng Wang nid = folio_nid(folio); 173733024536SHuang Ying /* 173833024536SHuang Ying * For memory tiering mode, cpupid of slow memory page is used 173933024536SHuang Ying * to record page access time. So use default value. 174033024536SHuang Ying */ 1741667ffc31SKefeng Wang if (node_is_toptier(nid)) 1742c4a8d2faSKefeng Wang last_cpupid = folio_last_cpupid(folio); 1743cda6d936SKefeng Wang target_nid = numa_migrate_prep(folio, vma, haddr, nid, &flags); 1744c5b5a3ddSYang Shi if (target_nid == NUMA_NO_NODE) { 1745667ffc31SKefeng Wang folio_put(folio); 1746c5b5a3ddSYang Shi goto out_map; 1747c5b5a3ddSYang Shi } 1748c5b5a3ddSYang Shi 174982b0f8c3SJan Kara spin_unlock(vmf->ptl); 17506a56ccbcSDavid Hildenbrand writable = false; 17518b1b436dSPeter Zijlstra 1752667ffc31SKefeng Wang migrated = migrate_misplaced_folio(folio, vma, target_nid); 17536688cc05SPeter Zijlstra if (migrated) { 17546688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 1755667ffc31SKefeng Wang nid = target_nid; 1756c5b5a3ddSYang Shi } else { 1757074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 1758c5b5a3ddSYang Shi vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 1759c5b5a3ddSYang Shi if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { 176082b0f8c3SJan Kara spin_unlock(vmf->ptl); 1761c5b5a3ddSYang Shi goto out; 1762c5b5a3ddSYang Shi } 1763c5b5a3ddSYang Shi goto out_map; 1764c5b5a3ddSYang Shi } 1765b8916634SMel Gorman 1766b8916634SMel Gorman out: 1767667ffc31SKefeng Wang if (nid != NUMA_NO_NODE) 1768667ffc31SKefeng Wang task_numa_fault(last_cpupid, nid, HPAGE_PMD_NR, flags); 17698191acbdSMel Gorman 1770d10e63f2SMel Gorman return 0; 1771c5b5a3ddSYang Shi 1772c5b5a3ddSYang Shi out_map: 1773c5b5a3ddSYang Shi /* Restore the PMD */ 1774c5b5a3ddSYang Shi pmd = pmd_modify(oldpmd, vma->vm_page_prot); 1775c5b5a3ddSYang Shi pmd = pmd_mkyoung(pmd); 17766a56ccbcSDavid Hildenbrand if (writable) 1777161e393cSRick Edgecombe pmd = pmd_mkwrite(pmd, vma); 1778c5b5a3ddSYang Shi set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); 1779c5b5a3ddSYang Shi update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); 1780c5b5a3ddSYang Shi spin_unlock(vmf->ptl); 1781c5b5a3ddSYang Shi goto out; 1782d10e63f2SMel Gorman } 1783d10e63f2SMel Gorman 1784319904adSHuang Ying /* 1785319904adSHuang Ying * Return true if we do MADV_FREE successfully on entire pmd page. 1786319904adSHuang Ying * Otherwise, return false. 1787319904adSHuang Ying */ 1788319904adSHuang Ying bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1789b8d3c4c3SMinchan Kim pmd_t *pmd, unsigned long addr, unsigned long next) 1790b8d3c4c3SMinchan Kim { 1791b8d3c4c3SMinchan Kim spinlock_t *ptl; 1792b8d3c4c3SMinchan Kim pmd_t orig_pmd; 1793fc986a38SKefeng Wang struct folio *folio; 1794b8d3c4c3SMinchan Kim struct mm_struct *mm = tlb->mm; 1795319904adSHuang Ying bool ret = false; 1796b8d3c4c3SMinchan Kim 1797ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 179807e32661SAneesh Kumar K.V 1799b6ec57f4SKirill A. Shutemov ptl = pmd_trans_huge_lock(pmd, vma); 1800b6ec57f4SKirill A. Shutemov if (!ptl) 180125eedabeSLinus Torvalds goto out_unlocked; 1802b8d3c4c3SMinchan Kim 1803b8d3c4c3SMinchan Kim orig_pmd = *pmd; 1804319904adSHuang Ying if (is_huge_zero_pmd(orig_pmd)) 1805b8d3c4c3SMinchan Kim goto out; 1806b8d3c4c3SMinchan Kim 180784c3fc4eSZi Yan if (unlikely(!pmd_present(orig_pmd))) { 180884c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 180984c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 181084c3fc4eSZi Yan goto out; 181184c3fc4eSZi Yan } 181284c3fc4eSZi Yan 1813fc986a38SKefeng Wang folio = pfn_folio(pmd_pfn(orig_pmd)); 1814b8d3c4c3SMinchan Kim /* 1815fc986a38SKefeng Wang * If other processes are mapping this folio, we couldn't discard 1816fc986a38SKefeng Wang * the folio unless they all do MADV_FREE so let's skip the folio. 1817b8d3c4c3SMinchan Kim */ 181820b18aadSYin Fengwei if (folio_estimated_sharers(folio) != 1) 1819b8d3c4c3SMinchan Kim goto out; 1820b8d3c4c3SMinchan Kim 1821fc986a38SKefeng Wang if (!folio_trylock(folio)) 1822b8d3c4c3SMinchan Kim goto out; 1823b8d3c4c3SMinchan Kim 1824b8d3c4c3SMinchan Kim /* 1825b8d3c4c3SMinchan Kim * If user want to discard part-pages of THP, split it so MADV_FREE 1826b8d3c4c3SMinchan Kim * will deactivate only them. 1827b8d3c4c3SMinchan Kim */ 1828b8d3c4c3SMinchan Kim if (next - addr != HPAGE_PMD_SIZE) { 1829fc986a38SKefeng Wang folio_get(folio); 1830b8d3c4c3SMinchan Kim spin_unlock(ptl); 1831fc986a38SKefeng Wang split_folio(folio); 1832fc986a38SKefeng Wang folio_unlock(folio); 1833fc986a38SKefeng Wang folio_put(folio); 1834b8d3c4c3SMinchan Kim goto out_unlocked; 1835b8d3c4c3SMinchan Kim } 1836b8d3c4c3SMinchan Kim 1837fc986a38SKefeng Wang if (folio_test_dirty(folio)) 1838fc986a38SKefeng Wang folio_clear_dirty(folio); 1839fc986a38SKefeng Wang folio_unlock(folio); 1840b8d3c4c3SMinchan Kim 1841b8d3c4c3SMinchan Kim if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { 184258ceeb6bSKirill A. Shutemov pmdp_invalidate(vma, addr, pmd); 1843b8d3c4c3SMinchan Kim orig_pmd = pmd_mkold(orig_pmd); 1844b8d3c4c3SMinchan Kim orig_pmd = pmd_mkclean(orig_pmd); 1845b8d3c4c3SMinchan Kim 1846b8d3c4c3SMinchan Kim set_pmd_at(mm, addr, pmd, orig_pmd); 1847b8d3c4c3SMinchan Kim tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 1848b8d3c4c3SMinchan Kim } 1849802a3a92SShaohua Li 18506a6fe9ebSKefeng Wang folio_mark_lazyfree(folio); 1851319904adSHuang Ying ret = true; 1852b8d3c4c3SMinchan Kim out: 1853b8d3c4c3SMinchan Kim spin_unlock(ptl); 1854b8d3c4c3SMinchan Kim out_unlocked: 1855b8d3c4c3SMinchan Kim return ret; 1856b8d3c4c3SMinchan Kim } 1857b8d3c4c3SMinchan Kim 1858953c66c2SAneesh Kumar K.V static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) 1859953c66c2SAneesh Kumar K.V { 1860953c66c2SAneesh Kumar K.V pgtable_t pgtable; 1861953c66c2SAneesh Kumar K.V 1862953c66c2SAneesh Kumar K.V pgtable = pgtable_trans_huge_withdraw(mm, pmd); 1863953c66c2SAneesh Kumar K.V pte_free(mm, pgtable); 1864c4812909SKirill A. Shutemov mm_dec_nr_ptes(mm); 1865953c66c2SAneesh Kumar K.V } 1866953c66c2SAneesh Kumar K.V 186771e3aac0SAndrea Arcangeli int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 1868f21760b1SShaohua Li pmd_t *pmd, unsigned long addr) 186971e3aac0SAndrea Arcangeli { 1870f5c8ad47SDavid Miller pmd_t orig_pmd; 1871da146769SKirill A. Shutemov spinlock_t *ptl; 1872da146769SKirill A. Shutemov 1873ed6a7935SPeter Zijlstra tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 187407e32661SAneesh Kumar K.V 1875b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 1876b6ec57f4SKirill A. Shutemov if (!ptl) 1877da146769SKirill A. Shutemov return 0; 1878a6bf2bb0SAneesh Kumar K.V /* 1879a6bf2bb0SAneesh Kumar K.V * For architectures like ppc64 we look at deposited pgtable 18808809aa2dSAneesh Kumar K.V * when calling pmdp_huge_get_and_clear. So do the 1881a6bf2bb0SAneesh Kumar K.V * pgtable_trans_huge_withdraw after finishing pmdp related 1882a6bf2bb0SAneesh Kumar K.V * operations. 1883a6bf2bb0SAneesh Kumar K.V */ 188493a98695SAneesh Kumar K.V orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, 1885fcbe08d6SMartin Schwidefsky tlb->fullmm); 1886e5136e87SRick Edgecombe arch_check_zapped_pmd(vma, orig_pmd); 1887f21760b1SShaohua Li tlb_remove_pmd_tlb_entry(tlb, pmd, addr); 18882484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 18893b6521f5SOliver O'Halloran if (arch_needs_pgtable_deposit()) 18903b6521f5SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 18914897c765SMatthew Wilcox spin_unlock(ptl); 1892da146769SKirill A. Shutemov } else if (is_huge_zero_pmd(orig_pmd)) { 1893c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1894bf929152SKirill A. Shutemov spin_unlock(ptl); 1895479f0abbSKirill A. Shutemov } else { 1896616b8371SZi Yan struct page *page = NULL; 1897616b8371SZi Yan int flush_needed = 1; 1898616b8371SZi Yan 1899616b8371SZi Yan if (pmd_present(orig_pmd)) { 1900616b8371SZi Yan page = pmd_page(orig_pmd); 1901cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 1902309381feSSasha Levin VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); 1903309381feSSasha Levin VM_BUG_ON_PAGE(!PageHead(page), page); 1904616b8371SZi Yan } else if (thp_migration_supported()) { 1905616b8371SZi Yan swp_entry_t entry; 1906616b8371SZi Yan 1907616b8371SZi Yan VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); 1908616b8371SZi Yan entry = pmd_to_swp_entry(orig_pmd); 1909af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 1910616b8371SZi Yan flush_needed = 0; 1911616b8371SZi Yan } else 1912616b8371SZi Yan WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); 1913616b8371SZi Yan 1914b5072380SKirill A. Shutemov if (PageAnon(page)) { 1915c14a6eb4SOliver O'Halloran zap_deposited_table(tlb->mm, pmd); 1916b5072380SKirill A. Shutemov add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); 1917b5072380SKirill A. Shutemov } else { 1918953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 1919953c66c2SAneesh Kumar K.V zap_deposited_table(tlb->mm, pmd); 1920fadae295SYang Shi add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); 1921b5072380SKirill A. Shutemov } 1922616b8371SZi Yan 1923bf929152SKirill A. Shutemov spin_unlock(ptl); 1924616b8371SZi Yan if (flush_needed) 1925e77b0852SAneesh Kumar K.V tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); 1926479f0abbSKirill A. Shutemov } 1927da146769SKirill A. Shutemov return 1; 192871e3aac0SAndrea Arcangeli } 192971e3aac0SAndrea Arcangeli 19301dd38b6cSAneesh Kumar K.V #ifndef pmd_move_must_withdraw 19311dd38b6cSAneesh Kumar K.V static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, 19321dd38b6cSAneesh Kumar K.V spinlock_t *old_pmd_ptl, 19331dd38b6cSAneesh Kumar K.V struct vm_area_struct *vma) 19341dd38b6cSAneesh Kumar K.V { 19351dd38b6cSAneesh Kumar K.V /* 19361dd38b6cSAneesh Kumar K.V * With split pmd lock we also need to move preallocated 19371dd38b6cSAneesh Kumar K.V * PTE page table if new_pmd is on different PMD page table. 19381dd38b6cSAneesh Kumar K.V * 19391dd38b6cSAneesh Kumar K.V * We also don't deposit and withdraw tables for file pages. 19401dd38b6cSAneesh Kumar K.V */ 19411dd38b6cSAneesh Kumar K.V return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); 19421dd38b6cSAneesh Kumar K.V } 19431dd38b6cSAneesh Kumar K.V #endif 19441dd38b6cSAneesh Kumar K.V 1945ab6e3d09SNaoya Horiguchi static pmd_t move_soft_dirty_pmd(pmd_t pmd) 1946ab6e3d09SNaoya Horiguchi { 1947ab6e3d09SNaoya Horiguchi #ifdef CONFIG_MEM_SOFT_DIRTY 1948ab6e3d09SNaoya Horiguchi if (unlikely(is_pmd_migration_entry(pmd))) 1949ab6e3d09SNaoya Horiguchi pmd = pmd_swp_mksoft_dirty(pmd); 1950ab6e3d09SNaoya Horiguchi else if (pmd_present(pmd)) 1951ab6e3d09SNaoya Horiguchi pmd = pmd_mksoft_dirty(pmd); 1952ab6e3d09SNaoya Horiguchi #endif 1953ab6e3d09SNaoya Horiguchi return pmd; 1954ab6e3d09SNaoya Horiguchi } 1955ab6e3d09SNaoya Horiguchi 1956bf8616d5SHugh Dickins bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, 1957b8aa9d9dSWei Yang unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) 195837a1c49aSAndrea Arcangeli { 1959bf929152SKirill A. Shutemov spinlock_t *old_ptl, *new_ptl; 196037a1c49aSAndrea Arcangeli pmd_t pmd; 196137a1c49aSAndrea Arcangeli struct mm_struct *mm = vma->vm_mm; 19625d190420SAaron Lu bool force_flush = false; 196337a1c49aSAndrea Arcangeli 196437a1c49aSAndrea Arcangeli /* 196537a1c49aSAndrea Arcangeli * The destination pmd shouldn't be established, free_pgtables() 1966a5be621eSHugh Dickins * should have released it; but move_page_tables() might have already 1967a5be621eSHugh Dickins * inserted a page table, if racing against shmem/file collapse. 196837a1c49aSAndrea Arcangeli */ 1969a5be621eSHugh Dickins if (!pmd_none(*new_pmd)) { 197037a1c49aSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*new_pmd)); 19714b471e88SKirill A. Shutemov return false; 197237a1c49aSAndrea Arcangeli } 197337a1c49aSAndrea Arcangeli 1974bf929152SKirill A. Shutemov /* 1975bf929152SKirill A. Shutemov * We don't have to worry about the ordering of src and dst 1976c1e8d7c6SMichel Lespinasse * ptlocks because exclusive mmap_lock prevents deadlock. 1977bf929152SKirill A. Shutemov */ 1978b6ec57f4SKirill A. Shutemov old_ptl = __pmd_trans_huge_lock(old_pmd, vma); 1979b6ec57f4SKirill A. Shutemov if (old_ptl) { 1980bf929152SKirill A. Shutemov new_ptl = pmd_lockptr(mm, new_pmd); 1981bf929152SKirill A. Shutemov if (new_ptl != old_ptl) 1982bf929152SKirill A. Shutemov spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); 19838809aa2dSAneesh Kumar K.V pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); 1984eb66ae03SLinus Torvalds if (pmd_present(pmd)) 1985a2ce2666SAaron Lu force_flush = true; 198637a1c49aSAndrea Arcangeli VM_BUG_ON(!pmd_none(*new_pmd)); 19873592806cSKirill A. Shutemov 19881dd38b6cSAneesh Kumar K.V if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { 1989b3084f4dSAneesh Kumar K.V pgtable_t pgtable; 19903592806cSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); 19913592806cSKirill A. Shutemov pgtable_trans_huge_deposit(mm, new_pmd, pgtable); 19923592806cSKirill A. Shutemov } 1993ab6e3d09SNaoya Horiguchi pmd = move_soft_dirty_pmd(pmd); 1994ab6e3d09SNaoya Horiguchi set_pmd_at(mm, new_addr, new_pmd, pmd); 19955d190420SAaron Lu if (force_flush) 19967c38f181SMiaohe Lin flush_pmd_tlb_range(vma, old_addr, old_addr + PMD_SIZE); 1997eb66ae03SLinus Torvalds if (new_ptl != old_ptl) 1998eb66ae03SLinus Torvalds spin_unlock(new_ptl); 1999bf929152SKirill A. Shutemov spin_unlock(old_ptl); 20004b471e88SKirill A. Shutemov return true; 200137a1c49aSAndrea Arcangeli } 20024b471e88SKirill A. Shutemov return false; 200337a1c49aSAndrea Arcangeli } 200437a1c49aSAndrea Arcangeli 2005f123d74aSMel Gorman /* 2006f123d74aSMel Gorman * Returns 2007f123d74aSMel Gorman * - 0 if PMD could not be locked 2008f0953a1bSIngo Molnar * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary 2009e346e668SYang Shi * or if prot_numa but THP migration is not supported 2010f0953a1bSIngo Molnar * - HPAGE_PMD_NR if protections changed and TLB flush necessary 2011f123d74aSMel Gorman */ 20124a18419fSNadav Amit int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, 20134a18419fSNadav Amit pmd_t *pmd, unsigned long addr, pgprot_t newprot, 20144a18419fSNadav Amit unsigned long cp_flags) 2015cd7548abSJohannes Weiner { 2016cd7548abSJohannes Weiner struct mm_struct *mm = vma->vm_mm; 2017bf929152SKirill A. Shutemov spinlock_t *ptl; 2018c9fe6656SNadav Amit pmd_t oldpmd, entry; 201958705444SPeter Xu bool prot_numa = cp_flags & MM_CP_PROT_NUMA; 2020292924b2SPeter Xu bool uffd_wp = cp_flags & MM_CP_UFFD_WP; 2021292924b2SPeter Xu bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; 20226a56ccbcSDavid Hildenbrand int ret = 1; 2023cd7548abSJohannes Weiner 20244a18419fSNadav Amit tlb_change_page_size(tlb, HPAGE_PMD_SIZE); 20254a18419fSNadav Amit 2026e346e668SYang Shi if (prot_numa && !thp_migration_supported()) 2027e346e668SYang Shi return 1; 2028e346e668SYang Shi 2029b6ec57f4SKirill A. Shutemov ptl = __pmd_trans_huge_lock(pmd, vma); 20300a85e51dSKirill A. Shutemov if (!ptl) 20310a85e51dSKirill A. Shutemov return 0; 20320a85e51dSKirill A. Shutemov 203384c3fc4eSZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 203484c3fc4eSZi Yan if (is_swap_pmd(*pmd)) { 203584c3fc4eSZi Yan swp_entry_t entry = pmd_to_swp_entry(*pmd); 2036d986ba2bSKefeng Wang struct folio *folio = page_folio(pfn_swap_entry_to_page(entry)); 203724bf08c4SDavid Hildenbrand pmd_t newpmd; 203884c3fc4eSZi Yan 203984c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd)); 20404dd845b5SAlistair Popple if (is_writable_migration_entry(entry)) { 204184c3fc4eSZi Yan /* 204284c3fc4eSZi Yan * A protection check is difficult so 204384c3fc4eSZi Yan * just be safe and disable write 204484c3fc4eSZi Yan */ 2045d986ba2bSKefeng Wang if (folio_test_anon(folio)) 20466c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(swp_offset(entry)); 20476c287605SDavid Hildenbrand else 20486c287605SDavid Hildenbrand entry = make_readable_migration_entry(swp_offset(entry)); 204984c3fc4eSZi Yan newpmd = swp_entry_to_pmd(entry); 2050ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pmd)) 2051ab6e3d09SNaoya Horiguchi newpmd = pmd_swp_mksoft_dirty(newpmd); 205224bf08c4SDavid Hildenbrand } else { 205324bf08c4SDavid Hildenbrand newpmd = *pmd; 205484c3fc4eSZi Yan } 205524bf08c4SDavid Hildenbrand 205624bf08c4SDavid Hildenbrand if (uffd_wp) 205724bf08c4SDavid Hildenbrand newpmd = pmd_swp_mkuffd_wp(newpmd); 205824bf08c4SDavid Hildenbrand else if (uffd_wp_resolve) 205924bf08c4SDavid Hildenbrand newpmd = pmd_swp_clear_uffd_wp(newpmd); 206024bf08c4SDavid Hildenbrand if (!pmd_same(*pmd, newpmd)) 206124bf08c4SDavid Hildenbrand set_pmd_at(mm, addr, pmd, newpmd); 206284c3fc4eSZi Yan goto unlock; 206384c3fc4eSZi Yan } 206484c3fc4eSZi Yan #endif 206584c3fc4eSZi Yan 2066a1a3a2fcSHuang Ying if (prot_numa) { 2067d986ba2bSKefeng Wang struct folio *folio; 206833024536SHuang Ying bool toptier; 2069e944fd67SMel Gorman /* 2070e944fd67SMel Gorman * Avoid trapping faults against the zero page. The read-only 2071e944fd67SMel Gorman * data is likely to be read-cached on the local CPU and 2072e944fd67SMel Gorman * local/remote hits to the zero page are not interesting. 2073e944fd67SMel Gorman */ 2074a1a3a2fcSHuang Ying if (is_huge_zero_pmd(*pmd)) 20750a85e51dSKirill A. Shutemov goto unlock; 2076e944fd67SMel Gorman 2077a1a3a2fcSHuang Ying if (pmd_protnone(*pmd)) 20780a85e51dSKirill A. Shutemov goto unlock; 20790a85e51dSKirill A. Shutemov 2080d986ba2bSKefeng Wang folio = page_folio(pmd_page(*pmd)); 2081d986ba2bSKefeng Wang toptier = node_is_toptier(folio_nid(folio)); 2082a1a3a2fcSHuang Ying /* 2083a1a3a2fcSHuang Ying * Skip scanning top tier node if normal numa 2084a1a3a2fcSHuang Ying * balancing is disabled 2085a1a3a2fcSHuang Ying */ 2086a1a3a2fcSHuang Ying if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && 208733024536SHuang Ying toptier) 2088a1a3a2fcSHuang Ying goto unlock; 208933024536SHuang Ying 209033024536SHuang Ying if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && 209133024536SHuang Ying !toptier) 2092d986ba2bSKefeng Wang folio_xchg_access_time(folio, 2093d986ba2bSKefeng Wang jiffies_to_msecs(jiffies)); 2094a1a3a2fcSHuang Ying } 2095ced10803SKirill A. Shutemov /* 20963e4e28c5SMichel Lespinasse * In case prot_numa, we are under mmap_read_lock(mm). It's critical 2097ced10803SKirill A. Shutemov * to not clear pmd intermittently to avoid race with MADV_DONTNEED 20983e4e28c5SMichel Lespinasse * which is also under mmap_read_lock(mm): 2099ced10803SKirill A. Shutemov * 2100ced10803SKirill A. Shutemov * CPU0: CPU1: 2101ced10803SKirill A. Shutemov * change_huge_pmd(prot_numa=1) 2102ced10803SKirill A. Shutemov * pmdp_huge_get_and_clear_notify() 2103ced10803SKirill A. Shutemov * madvise_dontneed() 2104ced10803SKirill A. Shutemov * zap_pmd_range() 2105ced10803SKirill A. Shutemov * pmd_trans_huge(*pmd) == 0 (without ptl) 2106ced10803SKirill A. Shutemov * // skip the pmd 2107ced10803SKirill A. Shutemov * set_pmd_at(); 2108ced10803SKirill A. Shutemov * // pmd is re-established 2109ced10803SKirill A. Shutemov * 2110ced10803SKirill A. Shutemov * The race makes MADV_DONTNEED miss the huge pmd and don't clear it 2111ced10803SKirill A. Shutemov * which may break userspace. 2112ced10803SKirill A. Shutemov * 21134f831457SNadav Amit * pmdp_invalidate_ad() is required to make sure we don't miss 2114ced10803SKirill A. Shutemov * dirty/young flags set by hardware. 2115ced10803SKirill A. Shutemov */ 21164f831457SNadav Amit oldpmd = pmdp_invalidate_ad(vma, addr, pmd); 2117ced10803SKirill A. Shutemov 2118c9fe6656SNadav Amit entry = pmd_modify(oldpmd, newprot); 2119f1eb1bacSPeter Xu if (uffd_wp) 2120292924b2SPeter Xu entry = pmd_mkuffd_wp(entry); 2121f1eb1bacSPeter Xu else if (uffd_wp_resolve) 2122292924b2SPeter Xu /* 2123292924b2SPeter Xu * Leave the write bit to be handled by PF interrupt 2124292924b2SPeter Xu * handler, then things like COW could be properly 2125292924b2SPeter Xu * handled. 2126292924b2SPeter Xu */ 2127292924b2SPeter Xu entry = pmd_clear_uffd_wp(entry); 2128c27f479eSDavid Hildenbrand 2129c27f479eSDavid Hildenbrand /* See change_pte_range(). */ 2130c27f479eSDavid Hildenbrand if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && !pmd_write(entry) && 2131c27f479eSDavid Hildenbrand can_change_pmd_writable(vma, addr, entry)) 2132161e393cSRick Edgecombe entry = pmd_mkwrite(entry, vma); 2133c27f479eSDavid Hildenbrand 2134f123d74aSMel Gorman ret = HPAGE_PMD_NR; 213556eecdb9SAneesh Kumar K.V set_pmd_at(mm, addr, pmd, entry); 21364a18419fSNadav Amit 2137c9fe6656SNadav Amit if (huge_pmd_needs_flush(oldpmd, entry)) 21384a18419fSNadav Amit tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); 21390a85e51dSKirill A. Shutemov unlock: 2140bf929152SKirill A. Shutemov spin_unlock(ptl); 2141cd7548abSJohannes Weiner return ret; 2142cd7548abSJohannes Weiner } 2143cd7548abSJohannes Weiner 2144adef4406SAndrea Arcangeli #ifdef CONFIG_USERFAULTFD 2145adef4406SAndrea Arcangeli /* 2146adef4406SAndrea Arcangeli * The PT lock for src_pmd and the mmap_lock for reading are held by 2147adef4406SAndrea Arcangeli * the caller, but it must return after releasing the page_table_lock. 2148adef4406SAndrea Arcangeli * Just move the page from src_pmd to dst_pmd if possible. 2149adef4406SAndrea Arcangeli * Return zero if succeeded in moving the page, -EAGAIN if it needs to be 2150adef4406SAndrea Arcangeli * repeated by the caller, or other errors in case of failure. 2151adef4406SAndrea Arcangeli */ 2152adef4406SAndrea Arcangeli int move_pages_huge_pmd(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd, pmd_t dst_pmdval, 2153adef4406SAndrea Arcangeli struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, 2154adef4406SAndrea Arcangeli unsigned long dst_addr, unsigned long src_addr) 2155adef4406SAndrea Arcangeli { 2156adef4406SAndrea Arcangeli pmd_t _dst_pmd, src_pmdval; 2157adef4406SAndrea Arcangeli struct page *src_page; 2158adef4406SAndrea Arcangeli struct folio *src_folio; 2159adef4406SAndrea Arcangeli struct anon_vma *src_anon_vma; 2160adef4406SAndrea Arcangeli spinlock_t *src_ptl, *dst_ptl; 2161adef4406SAndrea Arcangeli pgtable_t src_pgtable; 2162adef4406SAndrea Arcangeli struct mmu_notifier_range range; 2163adef4406SAndrea Arcangeli int err = 0; 2164adef4406SAndrea Arcangeli 2165adef4406SAndrea Arcangeli src_pmdval = *src_pmd; 2166adef4406SAndrea Arcangeli src_ptl = pmd_lockptr(mm, src_pmd); 2167adef4406SAndrea Arcangeli 2168adef4406SAndrea Arcangeli lockdep_assert_held(src_ptl); 2169adef4406SAndrea Arcangeli mmap_assert_locked(mm); 2170adef4406SAndrea Arcangeli 2171adef4406SAndrea Arcangeli /* Sanity checks before the operation */ 2172adef4406SAndrea Arcangeli if (WARN_ON_ONCE(!pmd_none(dst_pmdval)) || WARN_ON_ONCE(src_addr & ~HPAGE_PMD_MASK) || 2173adef4406SAndrea Arcangeli WARN_ON_ONCE(dst_addr & ~HPAGE_PMD_MASK)) { 2174adef4406SAndrea Arcangeli spin_unlock(src_ptl); 2175adef4406SAndrea Arcangeli return -EINVAL; 2176adef4406SAndrea Arcangeli } 2177adef4406SAndrea Arcangeli 2178adef4406SAndrea Arcangeli if (!pmd_trans_huge(src_pmdval)) { 2179adef4406SAndrea Arcangeli spin_unlock(src_ptl); 2180adef4406SAndrea Arcangeli if (is_pmd_migration_entry(src_pmdval)) { 2181adef4406SAndrea Arcangeli pmd_migration_entry_wait(mm, &src_pmdval); 2182adef4406SAndrea Arcangeli return -EAGAIN; 2183adef4406SAndrea Arcangeli } 2184adef4406SAndrea Arcangeli return -ENOENT; 2185adef4406SAndrea Arcangeli } 2186adef4406SAndrea Arcangeli 2187adef4406SAndrea Arcangeli src_page = pmd_page(src_pmdval); 2188adef4406SAndrea Arcangeli if (unlikely(!PageAnonExclusive(src_page))) { 2189adef4406SAndrea Arcangeli spin_unlock(src_ptl); 2190adef4406SAndrea Arcangeli return -EBUSY; 2191adef4406SAndrea Arcangeli } 2192adef4406SAndrea Arcangeli 2193adef4406SAndrea Arcangeli src_folio = page_folio(src_page); 2194adef4406SAndrea Arcangeli folio_get(src_folio); 2195adef4406SAndrea Arcangeli spin_unlock(src_ptl); 2196adef4406SAndrea Arcangeli 2197adef4406SAndrea Arcangeli flush_cache_range(src_vma, src_addr, src_addr + HPAGE_PMD_SIZE); 2198adef4406SAndrea Arcangeli mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, src_addr, 2199adef4406SAndrea Arcangeli src_addr + HPAGE_PMD_SIZE); 2200adef4406SAndrea Arcangeli mmu_notifier_invalidate_range_start(&range); 2201adef4406SAndrea Arcangeli 2202adef4406SAndrea Arcangeli folio_lock(src_folio); 2203adef4406SAndrea Arcangeli 2204adef4406SAndrea Arcangeli /* 2205adef4406SAndrea Arcangeli * split_huge_page walks the anon_vma chain without the page 2206adef4406SAndrea Arcangeli * lock. Serialize against it with the anon_vma lock, the page 2207adef4406SAndrea Arcangeli * lock is not enough. 2208adef4406SAndrea Arcangeli */ 2209adef4406SAndrea Arcangeli src_anon_vma = folio_get_anon_vma(src_folio); 2210adef4406SAndrea Arcangeli if (!src_anon_vma) { 2211adef4406SAndrea Arcangeli err = -EAGAIN; 2212adef4406SAndrea Arcangeli goto unlock_folio; 2213adef4406SAndrea Arcangeli } 2214adef4406SAndrea Arcangeli anon_vma_lock_write(src_anon_vma); 2215adef4406SAndrea Arcangeli 2216adef4406SAndrea Arcangeli dst_ptl = pmd_lockptr(mm, dst_pmd); 2217adef4406SAndrea Arcangeli double_pt_lock(src_ptl, dst_ptl); 2218adef4406SAndrea Arcangeli if (unlikely(!pmd_same(*src_pmd, src_pmdval) || 2219adef4406SAndrea Arcangeli !pmd_same(*dst_pmd, dst_pmdval))) { 2220adef4406SAndrea Arcangeli err = -EAGAIN; 2221adef4406SAndrea Arcangeli goto unlock_ptls; 2222adef4406SAndrea Arcangeli } 2223adef4406SAndrea Arcangeli if (folio_maybe_dma_pinned(src_folio) || 2224adef4406SAndrea Arcangeli !PageAnonExclusive(&src_folio->page)) { 2225adef4406SAndrea Arcangeli err = -EBUSY; 2226adef4406SAndrea Arcangeli goto unlock_ptls; 2227adef4406SAndrea Arcangeli } 2228adef4406SAndrea Arcangeli 2229adef4406SAndrea Arcangeli if (WARN_ON_ONCE(!folio_test_head(src_folio)) || 2230adef4406SAndrea Arcangeli WARN_ON_ONCE(!folio_test_anon(src_folio))) { 2231adef4406SAndrea Arcangeli err = -EBUSY; 2232adef4406SAndrea Arcangeli goto unlock_ptls; 2233adef4406SAndrea Arcangeli } 2234adef4406SAndrea Arcangeli 2235adef4406SAndrea Arcangeli folio_move_anon_rmap(src_folio, dst_vma); 2236adef4406SAndrea Arcangeli WRITE_ONCE(src_folio->index, linear_page_index(dst_vma, dst_addr)); 2237adef4406SAndrea Arcangeli 2238adef4406SAndrea Arcangeli src_pmdval = pmdp_huge_clear_flush(src_vma, src_addr, src_pmd); 2239adef4406SAndrea Arcangeli /* Folio got pinned from under us. Put it back and fail the move. */ 2240adef4406SAndrea Arcangeli if (folio_maybe_dma_pinned(src_folio)) { 2241adef4406SAndrea Arcangeli set_pmd_at(mm, src_addr, src_pmd, src_pmdval); 2242adef4406SAndrea Arcangeli err = -EBUSY; 2243adef4406SAndrea Arcangeli goto unlock_ptls; 2244adef4406SAndrea Arcangeli } 2245adef4406SAndrea Arcangeli 2246adef4406SAndrea Arcangeli _dst_pmd = mk_huge_pmd(&src_folio->page, dst_vma->vm_page_prot); 2247adef4406SAndrea Arcangeli /* Follow mremap() behavior and treat the entry dirty after the move */ 2248adef4406SAndrea Arcangeli _dst_pmd = pmd_mkwrite(pmd_mkdirty(_dst_pmd), dst_vma); 2249adef4406SAndrea Arcangeli set_pmd_at(mm, dst_addr, dst_pmd, _dst_pmd); 2250adef4406SAndrea Arcangeli 2251adef4406SAndrea Arcangeli src_pgtable = pgtable_trans_huge_withdraw(mm, src_pmd); 2252adef4406SAndrea Arcangeli pgtable_trans_huge_deposit(mm, dst_pmd, src_pgtable); 2253adef4406SAndrea Arcangeli unlock_ptls: 2254adef4406SAndrea Arcangeli double_pt_unlock(src_ptl, dst_ptl); 2255adef4406SAndrea Arcangeli anon_vma_unlock_write(src_anon_vma); 2256adef4406SAndrea Arcangeli put_anon_vma(src_anon_vma); 2257adef4406SAndrea Arcangeli unlock_folio: 2258adef4406SAndrea Arcangeli /* unblock rmap walks */ 2259adef4406SAndrea Arcangeli folio_unlock(src_folio); 2260adef4406SAndrea Arcangeli mmu_notifier_invalidate_range_end(&range); 2261adef4406SAndrea Arcangeli folio_put(src_folio); 2262adef4406SAndrea Arcangeli return err; 2263adef4406SAndrea Arcangeli } 2264adef4406SAndrea Arcangeli #endif /* CONFIG_USERFAULTFD */ 2265adef4406SAndrea Arcangeli 2266025c5b24SNaoya Horiguchi /* 22678f19b0c0SHuang Ying * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. 2268025c5b24SNaoya Horiguchi * 22698f19b0c0SHuang Ying * Note that if it returns page table lock pointer, this routine returns without 22708f19b0c0SHuang Ying * unlocking page table lock. So callers must unlock it. 2271025c5b24SNaoya Horiguchi */ 2272b6ec57f4SKirill A. Shutemov spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 2273025c5b24SNaoya Horiguchi { 2274b6ec57f4SKirill A. Shutemov spinlock_t *ptl; 2275b6ec57f4SKirill A. Shutemov ptl = pmd_lock(vma->vm_mm, pmd); 227684c3fc4eSZi Yan if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || 227784c3fc4eSZi Yan pmd_devmap(*pmd))) 2278b6ec57f4SKirill A. Shutemov return ptl; 2279b6ec57f4SKirill A. Shutemov spin_unlock(ptl); 2280b6ec57f4SKirill A. Shutemov return NULL; 2281025c5b24SNaoya Horiguchi } 2282025c5b24SNaoya Horiguchi 2283a00cc7d9SMatthew Wilcox /* 2284d965e390SMiaohe Lin * Returns page table lock pointer if a given pud maps a thp, NULL otherwise. 2285a00cc7d9SMatthew Wilcox * 2286d965e390SMiaohe Lin * Note that if it returns page table lock pointer, this routine returns without 2287d965e390SMiaohe Lin * unlocking page table lock. So callers must unlock it. 2288a00cc7d9SMatthew Wilcox */ 2289a00cc7d9SMatthew Wilcox spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 2290a00cc7d9SMatthew Wilcox { 2291a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2292a00cc7d9SMatthew Wilcox 2293a00cc7d9SMatthew Wilcox ptl = pud_lock(vma->vm_mm, pud); 2294a00cc7d9SMatthew Wilcox if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) 2295a00cc7d9SMatthew Wilcox return ptl; 2296a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2297a00cc7d9SMatthew Wilcox return NULL; 2298a00cc7d9SMatthew Wilcox } 2299a00cc7d9SMatthew Wilcox 2300a00cc7d9SMatthew Wilcox #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 2301a00cc7d9SMatthew Wilcox int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 2302a00cc7d9SMatthew Wilcox pud_t *pud, unsigned long addr) 2303a00cc7d9SMatthew Wilcox { 2304a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2305a00cc7d9SMatthew Wilcox 2306a00cc7d9SMatthew Wilcox ptl = __pud_trans_huge_lock(pud, vma); 2307a00cc7d9SMatthew Wilcox if (!ptl) 2308a00cc7d9SMatthew Wilcox return 0; 230974929079SMiaohe Lin 2310f32928abSAneesh Kumar K.V pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm); 2311a00cc7d9SMatthew Wilcox tlb_remove_pud_tlb_entry(tlb, pud, addr); 23122484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) { 2313a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2314a00cc7d9SMatthew Wilcox /* No zero page support yet */ 2315a00cc7d9SMatthew Wilcox } else { 2316a00cc7d9SMatthew Wilcox /* No support for anonymous PUD pages yet */ 2317a00cc7d9SMatthew Wilcox BUG(); 2318a00cc7d9SMatthew Wilcox } 2319a00cc7d9SMatthew Wilcox return 1; 2320a00cc7d9SMatthew Wilcox } 2321a00cc7d9SMatthew Wilcox 2322a00cc7d9SMatthew Wilcox static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 2323a00cc7d9SMatthew Wilcox unsigned long haddr) 2324a00cc7d9SMatthew Wilcox { 2325a00cc7d9SMatthew Wilcox VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); 2326a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2327a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); 2328a00cc7d9SMatthew Wilcox VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); 2329a00cc7d9SMatthew Wilcox 2330ce9311cfSYisheng Xie count_vm_event(THP_SPLIT_PUD); 2331a00cc7d9SMatthew Wilcox 2332ec8832d0SAlistair Popple pudp_huge_clear_flush(vma, haddr, pud); 2333a00cc7d9SMatthew Wilcox } 2334a00cc7d9SMatthew Wilcox 2335a00cc7d9SMatthew Wilcox void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 2336a00cc7d9SMatthew Wilcox unsigned long address) 2337a00cc7d9SMatthew Wilcox { 2338a00cc7d9SMatthew Wilcox spinlock_t *ptl; 2339ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2340a00cc7d9SMatthew Wilcox 23417d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 23426f4f13e8SJérôme Glisse address & HPAGE_PUD_MASK, 2343ac46d4f3SJérôme Glisse (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); 2344ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2345ac46d4f3SJérôme Glisse ptl = pud_lock(vma->vm_mm, pud); 2346a00cc7d9SMatthew Wilcox if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) 2347a00cc7d9SMatthew Wilcox goto out; 2348ac46d4f3SJérôme Glisse __split_huge_pud_locked(vma, pud, range.start); 2349a00cc7d9SMatthew Wilcox 2350a00cc7d9SMatthew Wilcox out: 2351a00cc7d9SMatthew Wilcox spin_unlock(ptl); 2352ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 2353a00cc7d9SMatthew Wilcox } 2354a00cc7d9SMatthew Wilcox #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 2355a00cc7d9SMatthew Wilcox 2356eef1b3baSKirill A. Shutemov static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, 2357eef1b3baSKirill A. Shutemov unsigned long haddr, pmd_t *pmd) 2358eef1b3baSKirill A. Shutemov { 2359eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2360eef1b3baSKirill A. Shutemov pgtable_t pgtable; 236142b2af2cSDavid Hildenbrand pmd_t _pmd, old_pmd; 2362c9c1ee20SHugh Dickins unsigned long addr; 2363c9c1ee20SHugh Dickins pte_t *pte; 2364eef1b3baSKirill A. Shutemov int i; 2365eef1b3baSKirill A. Shutemov 23660f10851eSJérôme Glisse /* 23670f10851eSJérôme Glisse * Leave pmd empty until pte is filled note that it is fine to delay 23680f10851eSJérôme Glisse * notification until mmu_notifier_invalidate_range_end() as we are 23690f10851eSJérôme Glisse * replacing a zero pmd write protected page with a zero pte write 23700f10851eSJérôme Glisse * protected page. 23710f10851eSJérôme Glisse * 2372ee65728eSMike Rapoport * See Documentation/mm/mmu_notifier.rst 23730f10851eSJérôme Glisse */ 237442b2af2cSDavid Hildenbrand old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); 2375eef1b3baSKirill A. Shutemov 2376eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2377eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2378eef1b3baSKirill A. Shutemov 2379c9c1ee20SHugh Dickins pte = pte_offset_map(&_pmd, haddr); 2380c9c1ee20SHugh Dickins VM_BUG_ON(!pte); 2381c9c1ee20SHugh Dickins for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2382c9c1ee20SHugh Dickins pte_t entry; 2383c9c1ee20SHugh Dickins 2384c9c1ee20SHugh Dickins entry = pfn_pte(my_zero_pfn(addr), vma->vm_page_prot); 2385eef1b3baSKirill A. Shutemov entry = pte_mkspecial(entry); 238642b2af2cSDavid Hildenbrand if (pmd_uffd_wp(old_pmd)) 238742b2af2cSDavid Hildenbrand entry = pte_mkuffd_wp(entry); 2388c33c7948SRyan Roberts VM_BUG_ON(!pte_none(ptep_get(pte))); 2389c9c1ee20SHugh Dickins set_pte_at(mm, addr, pte, entry); 2390c9c1ee20SHugh Dickins pte++; 2391eef1b3baSKirill A. Shutemov } 2392c9c1ee20SHugh Dickins pte_unmap(pte - 1); 2393eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2394eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2395eef1b3baSKirill A. Shutemov } 2396eef1b3baSKirill A. Shutemov 2397eef1b3baSKirill A. Shutemov static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 2398ba988280SKirill A. Shutemov unsigned long haddr, bool freeze) 2399eef1b3baSKirill A. Shutemov { 2400eef1b3baSKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2401*91b2978aSDavid Hildenbrand struct folio *folio; 2402eef1b3baSKirill A. Shutemov struct page *page; 2403eef1b3baSKirill A. Shutemov pgtable_t pgtable; 2404423ac9afSAneesh Kumar K.V pmd_t old_pmd, _pmd; 2405292924b2SPeter Xu bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; 24060ccf7f16SPeter Xu bool anon_exclusive = false, dirty = false; 24072ac015e2SKirill A. Shutemov unsigned long addr; 2408c9c1ee20SHugh Dickins pte_t *pte; 2409eef1b3baSKirill A. Shutemov int i; 2410eef1b3baSKirill A. Shutemov 2411eef1b3baSKirill A. Shutemov VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); 2412eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_start > haddr, vma); 2413eef1b3baSKirill A. Shutemov VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); 241484c3fc4eSZi Yan VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) 241584c3fc4eSZi Yan && !pmd_devmap(*pmd)); 2416eef1b3baSKirill A. Shutemov 2417eef1b3baSKirill A. Shutemov count_vm_event(THP_SPLIT_PMD); 2418eef1b3baSKirill A. Shutemov 2419d21b9e57SKirill A. Shutemov if (!vma_is_anonymous(vma)) { 2420ec8832d0SAlistair Popple old_pmd = pmdp_huge_clear_flush(vma, haddr, pmd); 2421953c66c2SAneesh Kumar K.V /* 2422953c66c2SAneesh Kumar K.V * We are going to unmap this huge page. So 2423953c66c2SAneesh Kumar K.V * just go ahead and zap it 2424953c66c2SAneesh Kumar K.V */ 2425953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 2426953c66c2SAneesh Kumar K.V zap_deposited_table(mm, pmd); 24272484ca9bSThomas Hellstrom (VMware) if (vma_is_special_huge(vma)) 2428d21b9e57SKirill A. Shutemov return; 242999fa8a48SHugh Dickins if (unlikely(is_pmd_migration_entry(old_pmd))) { 243099fa8a48SHugh Dickins swp_entry_t entry; 243199fa8a48SHugh Dickins 243299fa8a48SHugh Dickins entry = pmd_to_swp_entry(old_pmd); 2433af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 243499fa8a48SHugh Dickins } else { 243599fa8a48SHugh Dickins page = pmd_page(old_pmd); 243699fa8a48SHugh Dickins if (!PageDirty(page) && pmd_dirty(old_pmd)) 2437e1f1b157SHugh Dickins set_page_dirty(page); 243899fa8a48SHugh Dickins if (!PageReferenced(page) && pmd_young(old_pmd)) 2439d21b9e57SKirill A. Shutemov SetPageReferenced(page); 2440cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 2441d21b9e57SKirill A. Shutemov put_page(page); 244299fa8a48SHugh Dickins } 2443fadae295SYang Shi add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); 2444eef1b3baSKirill A. Shutemov return; 244599fa8a48SHugh Dickins } 244699fa8a48SHugh Dickins 24473b77e8c8SHugh Dickins if (is_huge_zero_pmd(*pmd)) { 24484645b9feSJérôme Glisse /* 24494645b9feSJérôme Glisse * FIXME: Do we want to invalidate secondary mmu by calling 24501af5a810SAlistair Popple * mmu_notifier_arch_invalidate_secondary_tlbs() see comments below 24511af5a810SAlistair Popple * inside __split_huge_pmd() ? 24524645b9feSJérôme Glisse * 24534645b9feSJérôme Glisse * We are going from a zero huge page write protected to zero 24544645b9feSJérôme Glisse * small page also write protected so it does not seems useful 24554645b9feSJérôme Glisse * to invalidate secondary mmu at this time. 24564645b9feSJérôme Glisse */ 2457eef1b3baSKirill A. Shutemov return __split_huge_zero_page_pmd(vma, haddr, pmd); 2458eef1b3baSKirill A. Shutemov } 2459eef1b3baSKirill A. Shutemov 2460423ac9afSAneesh Kumar K.V /* 2461423ac9afSAneesh Kumar K.V * Up to this point the pmd is present and huge and userland has the 2462423ac9afSAneesh Kumar K.V * whole access to the hugepage during the split (which happens in 2463423ac9afSAneesh Kumar K.V * place). If we overwrite the pmd with the not-huge version pointing 2464423ac9afSAneesh Kumar K.V * to the pte here (which of course we could if all CPUs were bug 2465423ac9afSAneesh Kumar K.V * free), userland could trigger a small page size TLB miss on the 2466423ac9afSAneesh Kumar K.V * small sized TLB while the hugepage TLB entry is still established in 2467423ac9afSAneesh Kumar K.V * the huge TLB. Some CPU doesn't like that. 246842742d9bSAlexander A. Klimov * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum 246942742d9bSAlexander A. Klimov * 383 on page 105. Intel should be safe but is also warns that it's 2470423ac9afSAneesh Kumar K.V * only safe if the permission and cache attributes of the two entries 2471423ac9afSAneesh Kumar K.V * loaded in the two TLB is identical (which should be the case here). 2472423ac9afSAneesh Kumar K.V * But it is generally safer to never allow small and huge TLB entries 2473423ac9afSAneesh Kumar K.V * for the same virtual address to be loaded simultaneously. So instead 2474423ac9afSAneesh Kumar K.V * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the 2475423ac9afSAneesh Kumar K.V * current pmd notpresent (atomically because here the pmd_trans_huge 2476423ac9afSAneesh Kumar K.V * must remain set at all times on the pmd until the split is complete 2477423ac9afSAneesh Kumar K.V * for this pmd), then we flush the SMP TLB and finally we write the 2478423ac9afSAneesh Kumar K.V * non-huge version of the pmd entry with pmd_populate. 2479423ac9afSAneesh Kumar K.V */ 2480423ac9afSAneesh Kumar K.V old_pmd = pmdp_invalidate(vma, haddr, pmd); 2481423ac9afSAneesh Kumar K.V 2482423ac9afSAneesh Kumar K.V pmd_migration = is_pmd_migration_entry(old_pmd); 24832e83ee1dSPeter Xu if (unlikely(pmd_migration)) { 248484c3fc4eSZi Yan swp_entry_t entry; 248584c3fc4eSZi Yan 2486423ac9afSAneesh Kumar K.V entry = pmd_to_swp_entry(old_pmd); 2487af5cdaf8SAlistair Popple page = pfn_swap_entry_to_page(entry); 24884dd845b5SAlistair Popple write = is_writable_migration_entry(entry); 24896c287605SDavid Hildenbrand if (PageAnon(page)) 24906c287605SDavid Hildenbrand anon_exclusive = is_readable_exclusive_migration_entry(entry); 24912e346877SPeter Xu young = is_migration_entry_young(entry); 24922e346877SPeter Xu dirty = is_migration_entry_dirty(entry); 24932e83ee1dSPeter Xu soft_dirty = pmd_swp_soft_dirty(old_pmd); 2494f45ec5ffSPeter Xu uffd_wp = pmd_swp_uffd_wp(old_pmd); 24952e83ee1dSPeter Xu } else { 2496423ac9afSAneesh Kumar K.V page = pmd_page(old_pmd); 2497*91b2978aSDavid Hildenbrand folio = page_folio(page); 24980ccf7f16SPeter Xu if (pmd_dirty(old_pmd)) { 24990ccf7f16SPeter Xu dirty = true; 2500*91b2978aSDavid Hildenbrand folio_set_dirty(folio); 25010ccf7f16SPeter Xu } 2502423ac9afSAneesh Kumar K.V write = pmd_write(old_pmd); 2503423ac9afSAneesh Kumar K.V young = pmd_young(old_pmd); 2504423ac9afSAneesh Kumar K.V soft_dirty = pmd_soft_dirty(old_pmd); 2505292924b2SPeter Xu uffd_wp = pmd_uffd_wp(old_pmd); 25066c287605SDavid Hildenbrand 2507*91b2978aSDavid Hildenbrand VM_WARN_ON_FOLIO(!folio_ref_count(folio), folio); 2508*91b2978aSDavid Hildenbrand VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); 25096c287605SDavid Hildenbrand 25106c287605SDavid Hildenbrand /* 25116c287605SDavid Hildenbrand * Without "freeze", we'll simply split the PMD, propagating the 25126c287605SDavid Hildenbrand * PageAnonExclusive() flag for each PTE by setting it for 25136c287605SDavid Hildenbrand * each subpage -- no need to (temporarily) clear. 25146c287605SDavid Hildenbrand * 25156c287605SDavid Hildenbrand * With "freeze" we want to replace mapped pages by 25166c287605SDavid Hildenbrand * migration entries right away. This is only possible if we 25176c287605SDavid Hildenbrand * managed to clear PageAnonExclusive() -- see 25186c287605SDavid Hildenbrand * set_pmd_migration_entry(). 25196c287605SDavid Hildenbrand * 25206c287605SDavid Hildenbrand * In case we cannot clear PageAnonExclusive(), split the PMD 25216c287605SDavid Hildenbrand * only and let try_to_migrate_one() fail later. 2522088b8aa5SDavid Hildenbrand * 2523088b8aa5SDavid Hildenbrand * See page_try_share_anon_rmap(): invalidate PMD first. 25246c287605SDavid Hildenbrand */ 2525*91b2978aSDavid Hildenbrand anon_exclusive = PageAnonExclusive(page); 25266c287605SDavid Hildenbrand if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) 25276c287605SDavid Hildenbrand freeze = false; 2528*91b2978aSDavid Hildenbrand if (!freeze) { 2529*91b2978aSDavid Hildenbrand rmap_t rmap_flags = RMAP_NONE; 2530*91b2978aSDavid Hildenbrand 2531*91b2978aSDavid Hildenbrand folio_ref_add(folio, HPAGE_PMD_NR - 1); 2532*91b2978aSDavid Hildenbrand if (anon_exclusive) 2533*91b2978aSDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 2534*91b2978aSDavid Hildenbrand folio_add_anon_rmap_ptes(folio, page, HPAGE_PMD_NR, 2535*91b2978aSDavid Hildenbrand vma, haddr, rmap_flags); 2536*91b2978aSDavid Hildenbrand } 25379d84604bSHugh Dickins } 2538eef1b3baSKirill A. Shutemov 2539423ac9afSAneesh Kumar K.V /* 2540423ac9afSAneesh Kumar K.V * Withdraw the table only after we mark the pmd entry invalid. 2541423ac9afSAneesh Kumar K.V * This's critical for some architectures (Power). 2542423ac9afSAneesh Kumar K.V */ 2543eef1b3baSKirill A. Shutemov pgtable = pgtable_trans_huge_withdraw(mm, pmd); 2544eef1b3baSKirill A. Shutemov pmd_populate(mm, &_pmd, pgtable); 2545eef1b3baSKirill A. Shutemov 2546c9c1ee20SHugh Dickins pte = pte_offset_map(&_pmd, haddr); 2547c9c1ee20SHugh Dickins VM_BUG_ON(!pte); 25482ac015e2SKirill A. Shutemov for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { 2549c9c1ee20SHugh Dickins pte_t entry; 2550eef1b3baSKirill A. Shutemov /* 2551eef1b3baSKirill A. Shutemov * Note that NUMA hinting access restrictions are not 2552eef1b3baSKirill A. Shutemov * transferred to avoid any possibility of altering 2553eef1b3baSKirill A. Shutemov * permissions across VMAs. 2554eef1b3baSKirill A. Shutemov */ 255584c3fc4eSZi Yan if (freeze || pmd_migration) { 2556ba988280SKirill A. Shutemov swp_entry_t swp_entry; 25574dd845b5SAlistair Popple if (write) 25584dd845b5SAlistair Popple swp_entry = make_writable_migration_entry( 25594dd845b5SAlistair Popple page_to_pfn(page + i)); 25606c287605SDavid Hildenbrand else if (anon_exclusive) 25616c287605SDavid Hildenbrand swp_entry = make_readable_exclusive_migration_entry( 25626c287605SDavid Hildenbrand page_to_pfn(page + i)); 25634dd845b5SAlistair Popple else 25644dd845b5SAlistair Popple swp_entry = make_readable_migration_entry( 25654dd845b5SAlistair Popple page_to_pfn(page + i)); 25662e346877SPeter Xu if (young) 25672e346877SPeter Xu swp_entry = make_migration_entry_young(swp_entry); 25682e346877SPeter Xu if (dirty) 25692e346877SPeter Xu swp_entry = make_migration_entry_dirty(swp_entry); 2570ba988280SKirill A. Shutemov entry = swp_entry_to_pte(swp_entry); 2571804dd150SAndrea Arcangeli if (soft_dirty) 2572804dd150SAndrea Arcangeli entry = pte_swp_mksoft_dirty(entry); 2573f45ec5ffSPeter Xu if (uffd_wp) 2574f45ec5ffSPeter Xu entry = pte_swp_mkuffd_wp(entry); 2575ba988280SKirill A. Shutemov } else { 25766d2329f8SAndrea Arcangeli entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); 25771462c52eSDavid Hildenbrand if (write) 2578161e393cSRick Edgecombe entry = pte_mkwrite(entry, vma); 2579eef1b3baSKirill A. Shutemov if (!young) 2580eef1b3baSKirill A. Shutemov entry = pte_mkold(entry); 2581e833bc50SPeter Xu /* NOTE: this may set soft-dirty too on some archs */ 2582e833bc50SPeter Xu if (dirty) 2583e833bc50SPeter Xu entry = pte_mkdirty(entry); 2584804dd150SAndrea Arcangeli if (soft_dirty) 2585804dd150SAndrea Arcangeli entry = pte_mksoft_dirty(entry); 2586292924b2SPeter Xu if (uffd_wp) 2587292924b2SPeter Xu entry = pte_mkuffd_wp(entry); 2588ba988280SKirill A. Shutemov } 2589c33c7948SRyan Roberts VM_BUG_ON(!pte_none(ptep_get(pte))); 25902ac015e2SKirill A. Shutemov set_pte_at(mm, addr, pte, entry); 2591c9c1ee20SHugh Dickins pte++; 2592eef1b3baSKirill A. Shutemov } 2593c9c1ee20SHugh Dickins pte_unmap(pte - 1); 2594eef1b3baSKirill A. Shutemov 2595cb67f428SHugh Dickins if (!pmd_migration) 2596cb67f428SHugh Dickins page_remove_rmap(page, vma, true); 259796d82debSHugh Dickins if (freeze) 259896d82debSHugh Dickins put_page(page); 2599eef1b3baSKirill A. Shutemov 2600eef1b3baSKirill A. Shutemov smp_wmb(); /* make pte visible before pmd */ 2601eef1b3baSKirill A. Shutemov pmd_populate(mm, pmd, pgtable); 2602eef1b3baSKirill A. Shutemov } 2603eef1b3baSKirill A. Shutemov 2604eef1b3baSKirill A. Shutemov void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 2605af28a988SMatthew Wilcox (Oracle) unsigned long address, bool freeze, struct folio *folio) 2606eef1b3baSKirill A. Shutemov { 2607eef1b3baSKirill A. Shutemov spinlock_t *ptl; 2608ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 2609eef1b3baSKirill A. Shutemov 26107d4a8be0SAlistair Popple mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 26116f4f13e8SJérôme Glisse address & HPAGE_PMD_MASK, 2612ac46d4f3SJérôme Glisse (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); 2613ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_start(&range); 2614ac46d4f3SJérôme Glisse ptl = pmd_lock(vma->vm_mm, pmd); 261533f4751eSNaoya Horiguchi 261633f4751eSNaoya Horiguchi /* 2617af28a988SMatthew Wilcox (Oracle) * If caller asks to setup a migration entry, we need a folio to check 2618af28a988SMatthew Wilcox (Oracle) * pmd against. Otherwise we can end up replacing wrong folio. 261933f4751eSNaoya Horiguchi */ 2620af28a988SMatthew Wilcox (Oracle) VM_BUG_ON(freeze && !folio); 262183a8441fSMatthew Wilcox (Oracle) VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); 262233f4751eSNaoya Horiguchi 26237f760917SDavid Hildenbrand if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || 262483a8441fSMatthew Wilcox (Oracle) is_pmd_migration_entry(*pmd)) { 2625cea33328SMiaohe Lin /* 2626cea33328SMiaohe Lin * It's safe to call pmd_page when folio is set because it's 2627cea33328SMiaohe Lin * guaranteed that pmd is present. 2628cea33328SMiaohe Lin */ 262983a8441fSMatthew Wilcox (Oracle) if (folio && folio != page_folio(pmd_page(*pmd))) 263083a8441fSMatthew Wilcox (Oracle) goto out; 2631ac46d4f3SJérôme Glisse __split_huge_pmd_locked(vma, pmd, range.start, freeze); 263283a8441fSMatthew Wilcox (Oracle) } 26337f760917SDavid Hildenbrand 2634e90309c9SKirill A. Shutemov out: 2635eef1b3baSKirill A. Shutemov spin_unlock(ptl); 2636ec8832d0SAlistair Popple mmu_notifier_invalidate_range_end(&range); 2637eef1b3baSKirill A. Shutemov } 2638eef1b3baSKirill A. Shutemov 2639fec89c10SKirill A. Shutemov void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, 2640af28a988SMatthew Wilcox (Oracle) bool freeze, struct folio *folio) 264194fcc585SAndrea Arcangeli { 264250722804SZach O'Keefe pmd_t *pmd = mm_find_pmd(vma->vm_mm, address); 264394fcc585SAndrea Arcangeli 264450722804SZach O'Keefe if (!pmd) 2645f72e7dcdSHugh Dickins return; 2646f72e7dcdSHugh Dickins 2647af28a988SMatthew Wilcox (Oracle) __split_huge_pmd(vma, pmd, address, freeze, folio); 264894fcc585SAndrea Arcangeli } 264994fcc585SAndrea Arcangeli 265071f9e58eSMiaohe Lin static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) 265171f9e58eSMiaohe Lin { 265271f9e58eSMiaohe Lin /* 265371f9e58eSMiaohe Lin * If the new address isn't hpage aligned and it could previously 265471f9e58eSMiaohe Lin * contain an hugepage: check if we need to split an huge pmd. 265571f9e58eSMiaohe Lin */ 265671f9e58eSMiaohe Lin if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && 265771f9e58eSMiaohe Lin range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), 265871f9e58eSMiaohe Lin ALIGN(address, HPAGE_PMD_SIZE))) 265971f9e58eSMiaohe Lin split_huge_pmd_address(vma, address, false, NULL); 266071f9e58eSMiaohe Lin } 266171f9e58eSMiaohe Lin 2662e1b9996bSKirill A. Shutemov void vma_adjust_trans_huge(struct vm_area_struct *vma, 266394fcc585SAndrea Arcangeli unsigned long start, 266494fcc585SAndrea Arcangeli unsigned long end, 266594fcc585SAndrea Arcangeli long adjust_next) 266694fcc585SAndrea Arcangeli { 266771f9e58eSMiaohe Lin /* Check if we need to split start first. */ 266871f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, start); 266971f9e58eSMiaohe Lin 267071f9e58eSMiaohe Lin /* Check if we need to split end next. */ 267171f9e58eSMiaohe Lin split_huge_pmd_if_needed(vma, end); 267294fcc585SAndrea Arcangeli 267394fcc585SAndrea Arcangeli /* 267468540502SMatthew Wilcox (Oracle) * If we're also updating the next vma vm_start, 267571f9e58eSMiaohe Lin * check if we need to split it. 267694fcc585SAndrea Arcangeli */ 267794fcc585SAndrea Arcangeli if (adjust_next > 0) { 267868540502SMatthew Wilcox (Oracle) struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end); 267994fcc585SAndrea Arcangeli unsigned long nstart = next->vm_start; 2680f9d86a60SWei Yang nstart += adjust_next; 268171f9e58eSMiaohe Lin split_huge_pmd_if_needed(next, nstart); 268294fcc585SAndrea Arcangeli } 268394fcc585SAndrea Arcangeli } 2684e9b61f19SKirill A. Shutemov 2685684555aaSMatthew Wilcox (Oracle) static void unmap_folio(struct folio *folio) 2686e9b61f19SKirill A. Shutemov { 2687a98a2f0cSAlistair Popple enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | 26883027c6f8SBaolin Wang TTU_SYNC | TTU_BATCH_FLUSH; 2689e9b61f19SKirill A. Shutemov 2690684555aaSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2691e9b61f19SKirill A. Shutemov 2692a98a2f0cSAlistair Popple /* 2693a98a2f0cSAlistair Popple * Anon pages need migration entries to preserve them, but file 2694a98a2f0cSAlistair Popple * pages can simply be left unmapped, then faulted back on demand. 2695a98a2f0cSAlistair Popple * If that is ever changed (perhaps for mlock), update remap_page(). 2696a98a2f0cSAlistair Popple */ 26974b8554c5SMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 26984b8554c5SMatthew Wilcox (Oracle) try_to_migrate(folio, ttu_flags); 2699a98a2f0cSAlistair Popple else 2700869f7ee6SMatthew Wilcox (Oracle) try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); 27013027c6f8SBaolin Wang 27023027c6f8SBaolin Wang try_to_unmap_flush(); 2703bd56086fSKirill A. Shutemov } 2704bd56086fSKirill A. Shutemov 27054eecb8b9SMatthew Wilcox (Oracle) static void remap_page(struct folio *folio, unsigned long nr) 2706e9b61f19SKirill A. Shutemov { 27074eecb8b9SMatthew Wilcox (Oracle) int i = 0; 2708ab02c252SHugh Dickins 2709684555aaSMatthew Wilcox (Oracle) /* If unmap_folio() uses try_to_migrate() on file, remove this check */ 27104eecb8b9SMatthew Wilcox (Oracle) if (!folio_test_anon(folio)) 2711ab02c252SHugh Dickins return; 27124eecb8b9SMatthew Wilcox (Oracle) for (;;) { 27134eecb8b9SMatthew Wilcox (Oracle) remove_migration_ptes(folio, folio, true); 27144eecb8b9SMatthew Wilcox (Oracle) i += folio_nr_pages(folio); 27154eecb8b9SMatthew Wilcox (Oracle) if (i >= nr) 27164eecb8b9SMatthew Wilcox (Oracle) break; 27174eecb8b9SMatthew Wilcox (Oracle) folio = folio_next(folio); 2718e9b61f19SKirill A. Shutemov } 2719ace71a19SKirill A. Shutemov } 2720e9b61f19SKirill A. Shutemov 272194866635SAlex Shi static void lru_add_page_tail(struct page *head, struct page *tail, 272288dcb9a3SAlex Shi struct lruvec *lruvec, struct list_head *list) 272388dcb9a3SAlex Shi { 272494866635SAlex Shi VM_BUG_ON_PAGE(!PageHead(head), head); 272594866635SAlex Shi VM_BUG_ON_PAGE(PageCompound(tail), head); 272694866635SAlex Shi VM_BUG_ON_PAGE(PageLRU(tail), head); 27276168d0daSAlex Shi lockdep_assert_held(&lruvec->lru_lock); 272888dcb9a3SAlex Shi 27296dbb5741SAlex Shi if (list) { 273088dcb9a3SAlex Shi /* page reclaim is reclaiming a huge page */ 27316dbb5741SAlex Shi VM_WARN_ON(PageLRU(head)); 273294866635SAlex Shi get_page(tail); 273394866635SAlex Shi list_add_tail(&tail->lru, list); 273488dcb9a3SAlex Shi } else { 27356dbb5741SAlex Shi /* head is still on lru (and we have it frozen) */ 27366dbb5741SAlex Shi VM_WARN_ON(!PageLRU(head)); 273707ca7606SHugh Dickins if (PageUnevictable(tail)) 273807ca7606SHugh Dickins tail->mlock_count = 0; 273907ca7606SHugh Dickins else 27406dbb5741SAlex Shi list_add_tail(&tail->lru, &head->lru); 274107ca7606SHugh Dickins SetPageLRU(tail); 274288dcb9a3SAlex Shi } 274388dcb9a3SAlex Shi } 274488dcb9a3SAlex Shi 274507e09c48SDavid Hildenbrand static void __split_huge_page_tail(struct folio *folio, int tail, 2746e9b61f19SKirill A. Shutemov struct lruvec *lruvec, struct list_head *list) 2747e9b61f19SKirill A. Shutemov { 274807e09c48SDavid Hildenbrand struct page *head = &folio->page; 2749e9b61f19SKirill A. Shutemov struct page *page_tail = head + tail; 275007e09c48SDavid Hildenbrand /* 275107e09c48SDavid Hildenbrand * Careful: new_folio is not a "real" folio before we cleared PageTail. 275207e09c48SDavid Hildenbrand * Don't pass it around before clear_compound_head(). 275307e09c48SDavid Hildenbrand */ 275407e09c48SDavid Hildenbrand struct folio *new_folio = (struct folio *)page_tail; 2755e9b61f19SKirill A. Shutemov 27568df651c7SKirill A. Shutemov VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); 2757e9b61f19SKirill A. Shutemov 2758e9b61f19SKirill A. Shutemov /* 2759605ca5edSKonstantin Khlebnikov * Clone page flags before unfreezing refcount. 2760605ca5edSKonstantin Khlebnikov * 2761605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow flags change, 27628958b249SHaitao Shi * for example lock_page() which set PG_waiters. 27636c287605SDavid Hildenbrand * 27646c287605SDavid Hildenbrand * Note that for mapped sub-pages of an anonymous THP, 2765684555aaSMatthew Wilcox (Oracle) * PG_anon_exclusive has been cleared in unmap_folio() and is stored in 27666c287605SDavid Hildenbrand * the migration entry instead from where remap_page() will restore it. 27676c287605SDavid Hildenbrand * We can still have PG_anon_exclusive set on effectively unmapped and 27686c287605SDavid Hildenbrand * unreferenced sub-pages of an anonymous THP: we can simply drop 27696c287605SDavid Hildenbrand * PG_anon_exclusive (-> PG_mappedtodisk) for these here. 2770e9b61f19SKirill A. Shutemov */ 2771e9b61f19SKirill A. Shutemov page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; 2772e9b61f19SKirill A. Shutemov page_tail->flags |= (head->flags & 2773e9b61f19SKirill A. Shutemov ((1L << PG_referenced) | 2774e9b61f19SKirill A. Shutemov (1L << PG_swapbacked) | 277538d8b4e6SHuang Ying (1L << PG_swapcache) | 2776e9b61f19SKirill A. Shutemov (1L << PG_mlocked) | 2777e9b61f19SKirill A. Shutemov (1L << PG_uptodate) | 2778e9b61f19SKirill A. Shutemov (1L << PG_active) | 27791899ad18SJohannes Weiner (1L << PG_workingset) | 2780e9b61f19SKirill A. Shutemov (1L << PG_locked) | 2781b8d3c4c3SMinchan Kim (1L << PG_unevictable) | 2782b0284cd2SCatalin Marinas #ifdef CONFIG_ARCH_USES_PG_ARCH_X 278372e6afa0SCatalin Marinas (1L << PG_arch_2) | 2784ef6458b1SPeter Collingbourne (1L << PG_arch_3) | 278572e6afa0SCatalin Marinas #endif 2786ec1c86b2SYu Zhao (1L << PG_dirty) | 2787ec1c86b2SYu Zhao LRU_GEN_MASK | LRU_REFS_MASK)); 2788e9b61f19SKirill A. Shutemov 2789cb67f428SHugh Dickins /* ->mapping in first and second tail page is replaced by other uses */ 2790173d9d9fSHugh Dickins VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, 2791173d9d9fSHugh Dickins page_tail); 2792173d9d9fSHugh Dickins page_tail->mapping = head->mapping; 2793173d9d9fSHugh Dickins page_tail->index = head->index + tail; 279471e2d666SMel Gorman 279571e2d666SMel Gorman /* 2796cfeed8ffSDavid Hildenbrand * page->private should not be set in tail pages. Fix up and warn once 2797cfeed8ffSDavid Hildenbrand * if private is unexpectedly set. 279871e2d666SMel Gorman */ 2799cfeed8ffSDavid Hildenbrand if (unlikely(page_tail->private)) { 2800cfeed8ffSDavid Hildenbrand VM_WARN_ON_ONCE_PAGE(true, page_tail); 2801b653db77SMatthew Wilcox (Oracle) page_tail->private = 0; 280271e2d666SMel Gorman } 280307e09c48SDavid Hildenbrand if (folio_test_swapcache(folio)) 280407e09c48SDavid Hildenbrand new_folio->swap.val = folio->swap.val + tail; 2805173d9d9fSHugh Dickins 2806605ca5edSKonstantin Khlebnikov /* Page flags must be visible before we make the page non-compound. */ 2807e9b61f19SKirill A. Shutemov smp_wmb(); 2808e9b61f19SKirill A. Shutemov 2809605ca5edSKonstantin Khlebnikov /* 2810605ca5edSKonstantin Khlebnikov * Clear PageTail before unfreezing page refcount. 2811605ca5edSKonstantin Khlebnikov * 2812605ca5edSKonstantin Khlebnikov * After successful get_page_unless_zero() might follow put_page() 2813605ca5edSKonstantin Khlebnikov * which needs correct compound_head(). 2814605ca5edSKonstantin Khlebnikov */ 2815e9b61f19SKirill A. Shutemov clear_compound_head(page_tail); 2816e9b61f19SKirill A. Shutemov 2817605ca5edSKonstantin Khlebnikov /* Finally unfreeze refcount. Additional reference from page cache. */ 2818b7542769SKefeng Wang page_ref_unfreeze(page_tail, 1 + (!folio_test_anon(folio) || 2819b7542769SKefeng Wang folio_test_swapcache(folio))); 2820605ca5edSKonstantin Khlebnikov 2821b7542769SKefeng Wang if (folio_test_young(folio)) 2822b7542769SKefeng Wang folio_set_young(new_folio); 2823b7542769SKefeng Wang if (folio_test_idle(folio)) 2824b7542769SKefeng Wang folio_set_idle(new_folio); 2825e9b61f19SKirill A. Shutemov 2826c8253011SKefeng Wang folio_xchg_last_cpupid(new_folio, folio_last_cpupid(folio)); 282794723aafSMichal Hocko 282894723aafSMichal Hocko /* 282994723aafSMichal Hocko * always add to the tail because some iterators expect new 283094723aafSMichal Hocko * pages to show after the currently processed elements - e.g. 283194723aafSMichal Hocko * migrate_pages 283294723aafSMichal Hocko */ 2833e9b61f19SKirill A. Shutemov lru_add_page_tail(head, page_tail, lruvec, list); 2834e9b61f19SKirill A. Shutemov } 2835e9b61f19SKirill A. Shutemov 2836baa355fdSKirill A. Shutemov static void __split_huge_page(struct page *page, struct list_head *list, 2837b6769834SAlex Shi pgoff_t end) 2838e9b61f19SKirill A. Shutemov { 2839e809c3feSMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2840e809c3feSMatthew Wilcox (Oracle) struct page *head = &folio->page; 2841e9b61f19SKirill A. Shutemov struct lruvec *lruvec; 28424101196bSMatthew Wilcox (Oracle) struct address_space *swap_cache = NULL; 28434101196bSMatthew Wilcox (Oracle) unsigned long offset = 0; 28448cce5475SKirill A. Shutemov unsigned int nr = thp_nr_pages(head); 2845509f0069SHugh Dickins int i, nr_dropped = 0; 2846e9b61f19SKirill A. Shutemov 2847e9b61f19SKirill A. Shutemov /* complete memcg works before add pages to LRU */ 2848be6c8982SZhou Guanghui split_page_memcg(head, nr); 2849e9b61f19SKirill A. Shutemov 285007e09c48SDavid Hildenbrand if (folio_test_anon(folio) && folio_test_swapcache(folio)) { 285107e09c48SDavid Hildenbrand offset = swp_offset(folio->swap); 285207e09c48SDavid Hildenbrand swap_cache = swap_address_space(folio->swap); 28534101196bSMatthew Wilcox (Oracle) xa_lock(&swap_cache->i_pages); 28544101196bSMatthew Wilcox (Oracle) } 28554101196bSMatthew Wilcox (Oracle) 2856f0953a1bSIngo Molnar /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ 2857e809c3feSMatthew Wilcox (Oracle) lruvec = folio_lruvec_lock(folio); 2858b6769834SAlex Shi 2859eac96c3eSYang Shi ClearPageHasHWPoisoned(head); 2860eac96c3eSYang Shi 28618cce5475SKirill A. Shutemov for (i = nr - 1; i >= 1; i--) { 286207e09c48SDavid Hildenbrand __split_huge_page_tail(folio, i, lruvec, list); 2863d144bf62SHugh Dickins /* Some pages can be beyond EOF: drop them from page cache */ 2864baa355fdSKirill A. Shutemov if (head[i].index >= end) { 2865fb5c2029SMatthew Wilcox (Oracle) struct folio *tail = page_folio(head + i); 2866fb5c2029SMatthew Wilcox (Oracle) 2867d144bf62SHugh Dickins if (shmem_mapping(head->mapping)) 2868509f0069SHugh Dickins nr_dropped++; 2869fb5c2029SMatthew Wilcox (Oracle) else if (folio_test_clear_dirty(tail)) 2870fb5c2029SMatthew Wilcox (Oracle) folio_account_cleaned(tail, 2871fb5c2029SMatthew Wilcox (Oracle) inode_to_wb(folio->mapping->host)); 2872fb5c2029SMatthew Wilcox (Oracle) __filemap_remove_folio(tail, NULL); 2873fb5c2029SMatthew Wilcox (Oracle) folio_put(tail); 28744101196bSMatthew Wilcox (Oracle) } else if (!PageAnon(page)) { 28754101196bSMatthew Wilcox (Oracle) __xa_store(&head->mapping->i_pages, head[i].index, 28764101196bSMatthew Wilcox (Oracle) head + i, 0); 28774101196bSMatthew Wilcox (Oracle) } else if (swap_cache) { 28784101196bSMatthew Wilcox (Oracle) __xa_store(&swap_cache->i_pages, offset + i, 28794101196bSMatthew Wilcox (Oracle) head + i, 0); 2880baa355fdSKirill A. Shutemov } 2881baa355fdSKirill A. Shutemov } 2882e9b61f19SKirill A. Shutemov 2883e9b61f19SKirill A. Shutemov ClearPageCompound(head); 28846168d0daSAlex Shi unlock_page_lruvec(lruvec); 2885b6769834SAlex Shi /* Caller disabled irqs, so they are still disabled here */ 2886f7da677bSVlastimil Babka 28878cce5475SKirill A. Shutemov split_page_owner(head, nr); 2888f7da677bSVlastimil Babka 2889baa355fdSKirill A. Shutemov /* See comment in __split_huge_page_tail() */ 2890baa355fdSKirill A. Shutemov if (PageAnon(head)) { 2891aa5dc07fSMatthew Wilcox /* Additional pin to swap cache */ 28924101196bSMatthew Wilcox (Oracle) if (PageSwapCache(head)) { 289338d8b4e6SHuang Ying page_ref_add(head, 2); 28944101196bSMatthew Wilcox (Oracle) xa_unlock(&swap_cache->i_pages); 28954101196bSMatthew Wilcox (Oracle) } else { 2896baa355fdSKirill A. Shutemov page_ref_inc(head); 28974101196bSMatthew Wilcox (Oracle) } 2898baa355fdSKirill A. Shutemov } else { 2899aa5dc07fSMatthew Wilcox /* Additional pin to page cache */ 2900baa355fdSKirill A. Shutemov page_ref_add(head, 2); 2901b93b0163SMatthew Wilcox xa_unlock(&head->mapping->i_pages); 2902baa355fdSKirill A. Shutemov } 2903b6769834SAlex Shi local_irq_enable(); 2904e9b61f19SKirill A. Shutemov 2905509f0069SHugh Dickins if (nr_dropped) 2906509f0069SHugh Dickins shmem_uncharge(head->mapping->host, nr_dropped); 29074eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, nr); 2908e9b61f19SKirill A. Shutemov 290907e09c48SDavid Hildenbrand if (folio_test_swapcache(folio)) 291007e09c48SDavid Hildenbrand split_swap_cluster(folio->swap); 2911c4f9c701SHuang Ying 29128cce5475SKirill A. Shutemov for (i = 0; i < nr; i++) { 2913e9b61f19SKirill A. Shutemov struct page *subpage = head + i; 2914e9b61f19SKirill A. Shutemov if (subpage == page) 2915e9b61f19SKirill A. Shutemov continue; 2916e9b61f19SKirill A. Shutemov unlock_page(subpage); 2917e9b61f19SKirill A. Shutemov 2918e9b61f19SKirill A. Shutemov /* 2919e9b61f19SKirill A. Shutemov * Subpages may be freed if there wasn't any mapping 2920e9b61f19SKirill A. Shutemov * like if add_to_swap() is running on a lru page that 2921e9b61f19SKirill A. Shutemov * had its mapping zapped. And freeing these pages 2922e9b61f19SKirill A. Shutemov * requires taking the lru_lock so we do the put_page 2923e9b61f19SKirill A. Shutemov * of the tail pages after the split is complete. 2924e9b61f19SKirill A. Shutemov */ 29250b175468SMiaohe Lin free_page_and_swap_cache(subpage); 2926e9b61f19SKirill A. Shutemov } 2927e9b61f19SKirill A. Shutemov } 2928e9b61f19SKirill A. Shutemov 2929b8f593cdSHuang Ying /* Racy check whether the huge page can be split */ 2930d4b4084aSMatthew Wilcox (Oracle) bool can_split_folio(struct folio *folio, int *pextra_pins) 2931b8f593cdSHuang Ying { 2932b8f593cdSHuang Ying int extra_pins; 2933b8f593cdSHuang Ying 2934aa5dc07fSMatthew Wilcox /* Additional pins from page cache */ 2935d4b4084aSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 2936d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_test_swapcache(folio) ? 2937d4b4084aSMatthew Wilcox (Oracle) folio_nr_pages(folio) : 0; 2938b8f593cdSHuang Ying else 2939d4b4084aSMatthew Wilcox (Oracle) extra_pins = folio_nr_pages(folio); 2940b8f593cdSHuang Ying if (pextra_pins) 2941b8f593cdSHuang Ying *pextra_pins = extra_pins; 2942d4b4084aSMatthew Wilcox (Oracle) return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; 2943b8f593cdSHuang Ying } 2944b8f593cdSHuang Ying 29456d0a07edSAndrea Arcangeli /* 2946e9b61f19SKirill A. Shutemov * This function splits huge page into normal pages. @page can point to any 2947e9b61f19SKirill A. Shutemov * subpage of huge page to split. Split doesn't change the position of @page. 2948e9b61f19SKirill A. Shutemov * 2949e9b61f19SKirill A. Shutemov * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. 2950e9b61f19SKirill A. Shutemov * The huge page must be locked. 2951e9b61f19SKirill A. Shutemov * 2952e9b61f19SKirill A. Shutemov * If @list is null, tail pages will be added to LRU list, otherwise, to @list. 2953e9b61f19SKirill A. Shutemov * 2954e9b61f19SKirill A. Shutemov * Both head page and tail pages will inherit mapping, flags, and so on from 2955e9b61f19SKirill A. Shutemov * the hugepage. 2956e9b61f19SKirill A. Shutemov * 2957e9b61f19SKirill A. Shutemov * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if 2958e9b61f19SKirill A. Shutemov * they are not mapped. 2959e9b61f19SKirill A. Shutemov * 2960e9b61f19SKirill A. Shutemov * Returns 0 if the hugepage is split successfully. 2961e9b61f19SKirill A. Shutemov * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under 2962e9b61f19SKirill A. Shutemov * us. 2963e9b61f19SKirill A. Shutemov */ 2964e9b61f19SKirill A. Shutemov int split_huge_page_to_list(struct page *page, struct list_head *list) 2965e9b61f19SKirill A. Shutemov { 29664eecb8b9SMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 2967f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *ds_queue = get_deferred_split_queue(folio); 29683e9a13daSMatthew Wilcox (Oracle) XA_STATE(xas, &folio->mapping->i_pages, folio->index); 2969baa355fdSKirill A. Shutemov struct anon_vma *anon_vma = NULL; 2970baa355fdSKirill A. Shutemov struct address_space *mapping = NULL; 2971504e070dSYang Shi int extra_pins, ret; 2972006d3ff2SHugh Dickins pgoff_t end; 2973478d134eSXu Yu bool is_hzp; 2974e9b61f19SKirill A. Shutemov 29753e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); 29763e9a13daSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); 2977e9b61f19SKirill A. Shutemov 29783e9a13daSMatthew Wilcox (Oracle) is_hzp = is_huge_zero_page(&folio->page); 29794737edbbSNaoya Horiguchi if (is_hzp) { 29804737edbbSNaoya Horiguchi pr_warn_ratelimited("Called split_huge_page for huge zero page\n"); 2981478d134eSXu Yu return -EBUSY; 29824737edbbSNaoya Horiguchi } 2983478d134eSXu Yu 29843e9a13daSMatthew Wilcox (Oracle) if (folio_test_writeback(folio)) 298559807685SHuang Ying return -EBUSY; 298659807685SHuang Ying 29873e9a13daSMatthew Wilcox (Oracle) if (folio_test_anon(folio)) { 2988e9b61f19SKirill A. Shutemov /* 2989c1e8d7c6SMichel Lespinasse * The caller does not necessarily hold an mmap_lock that would 2990baa355fdSKirill A. Shutemov * prevent the anon_vma disappearing so we first we take a 2991baa355fdSKirill A. Shutemov * reference to it and then lock the anon_vma for write. This 29922f031c6fSMatthew Wilcox (Oracle) * is similar to folio_lock_anon_vma_read except the write lock 2993baa355fdSKirill A. Shutemov * is taken to serialise against parallel split or collapse 2994baa355fdSKirill A. Shutemov * operations. 2995e9b61f19SKirill A. Shutemov */ 299629eea9b5SMatthew Wilcox (Oracle) anon_vma = folio_get_anon_vma(folio); 2997e9b61f19SKirill A. Shutemov if (!anon_vma) { 2998e9b61f19SKirill A. Shutemov ret = -EBUSY; 2999e9b61f19SKirill A. Shutemov goto out; 3000e9b61f19SKirill A. Shutemov } 3001006d3ff2SHugh Dickins end = -1; 3002baa355fdSKirill A. Shutemov mapping = NULL; 3003e9b61f19SKirill A. Shutemov anon_vma_lock_write(anon_vma); 3004baa355fdSKirill A. Shutemov } else { 30056a3edd29SYin Fengwei gfp_t gfp; 30066a3edd29SYin Fengwei 30073e9a13daSMatthew Wilcox (Oracle) mapping = folio->mapping; 3008baa355fdSKirill A. Shutemov 3009baa355fdSKirill A. Shutemov /* Truncated ? */ 3010baa355fdSKirill A. Shutemov if (!mapping) { 3011baa355fdSKirill A. Shutemov ret = -EBUSY; 3012baa355fdSKirill A. Shutemov goto out; 3013baa355fdSKirill A. Shutemov } 3014baa355fdSKirill A. Shutemov 30156a3edd29SYin Fengwei gfp = current_gfp_context(mapping_gfp_mask(mapping) & 30166a3edd29SYin Fengwei GFP_RECLAIM_MASK); 30176a3edd29SYin Fengwei 30180201ebf2SDavid Howells if (!filemap_release_folio(folio, gfp)) { 30196a3edd29SYin Fengwei ret = -EBUSY; 30206a3edd29SYin Fengwei goto out; 30216a3edd29SYin Fengwei } 30226a3edd29SYin Fengwei 30233e9a13daSMatthew Wilcox (Oracle) xas_split_alloc(&xas, folio, folio_order(folio), gfp); 30246b24ca4aSMatthew Wilcox (Oracle) if (xas_error(&xas)) { 30256b24ca4aSMatthew Wilcox (Oracle) ret = xas_error(&xas); 30266b24ca4aSMatthew Wilcox (Oracle) goto out; 30276b24ca4aSMatthew Wilcox (Oracle) } 30286b24ca4aSMatthew Wilcox (Oracle) 3029baa355fdSKirill A. Shutemov anon_vma = NULL; 3030baa355fdSKirill A. Shutemov i_mmap_lock_read(mapping); 3031006d3ff2SHugh Dickins 3032006d3ff2SHugh Dickins /* 3033006d3ff2SHugh Dickins *__split_huge_page() may need to trim off pages beyond EOF: 3034006d3ff2SHugh Dickins * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, 3035006d3ff2SHugh Dickins * which cannot be nested inside the page tree lock. So note 3036006d3ff2SHugh Dickins * end now: i_size itself may be changed at any moment, but 30373e9a13daSMatthew Wilcox (Oracle) * folio lock is good enough to serialize the trimming. 3038006d3ff2SHugh Dickins */ 3039006d3ff2SHugh Dickins end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); 3040d144bf62SHugh Dickins if (shmem_mapping(mapping)) 3041d144bf62SHugh Dickins end = shmem_fallocend(mapping->host, end); 3042baa355fdSKirill A. Shutemov } 3043e9b61f19SKirill A. Shutemov 3044e9b61f19SKirill A. Shutemov /* 3045684555aaSMatthew Wilcox (Oracle) * Racy check if we can split the page, before unmap_folio() will 3046e9b61f19SKirill A. Shutemov * split PMDs 3047e9b61f19SKirill A. Shutemov */ 3048d4b4084aSMatthew Wilcox (Oracle) if (!can_split_folio(folio, &extra_pins)) { 3049fd4a7ac3SBaolin Wang ret = -EAGAIN; 3050e9b61f19SKirill A. Shutemov goto out_unlock; 3051e9b61f19SKirill A. Shutemov } 3052e9b61f19SKirill A. Shutemov 3053684555aaSMatthew Wilcox (Oracle) unmap_folio(folio); 3054e9b61f19SKirill A. Shutemov 3055b6769834SAlex Shi /* block interrupt reentry in xa_lock and spinlock */ 3056b6769834SAlex Shi local_irq_disable(); 3057baa355fdSKirill A. Shutemov if (mapping) { 3058baa355fdSKirill A. Shutemov /* 30593e9a13daSMatthew Wilcox (Oracle) * Check if the folio is present in page cache. 30603e9a13daSMatthew Wilcox (Oracle) * We assume all tail are present too, if folio is there. 3061baa355fdSKirill A. Shutemov */ 30626b24ca4aSMatthew Wilcox (Oracle) xas_lock(&xas); 30636b24ca4aSMatthew Wilcox (Oracle) xas_reset(&xas); 30643e9a13daSMatthew Wilcox (Oracle) if (xas_load(&xas) != folio) 3065baa355fdSKirill A. Shutemov goto fail; 3066baa355fdSKirill A. Shutemov } 3067baa355fdSKirill A. Shutemov 30680139aa7bSJoonsoo Kim /* Prevent deferred_split_scan() touching ->_refcount */ 3069364c1eebSYang Shi spin_lock(&ds_queue->split_queue_lock); 30703e9a13daSMatthew Wilcox (Oracle) if (folio_ref_freeze(folio, 1 + extra_pins)) { 30714375a553SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) { 3072364c1eebSYang Shi ds_queue->split_queue_len--; 30734375a553SMatthew Wilcox (Oracle) list_del(&folio->_deferred_list); 30749a982250SKirill A. Shutemov } 3075afb97172SWei Yang spin_unlock(&ds_queue->split_queue_lock); 307606d3eff6SKirill A. Shutemov if (mapping) { 30773e9a13daSMatthew Wilcox (Oracle) int nr = folio_nr_pages(folio); 3078bf9eceadSMuchun Song 30793e9a13daSMatthew Wilcox (Oracle) xas_split(&xas, folio, folio_order(folio)); 3080a48d5bdcSStefan Roesch if (folio_test_pmd_mappable(folio)) { 30813e9a13daSMatthew Wilcox (Oracle) if (folio_test_swapbacked(folio)) { 3082a48d5bdcSStefan Roesch __lruvec_stat_mod_folio(folio, 3083a48d5bdcSStefan Roesch NR_SHMEM_THPS, -nr); 30841ca7554dSMarek Szyprowski } else { 3085a48d5bdcSStefan Roesch __lruvec_stat_mod_folio(folio, 3086a48d5bdcSStefan Roesch NR_FILE_THPS, -nr); 30871ca7554dSMarek Szyprowski filemap_nr_thps_dec(mapping); 30881ca7554dSMarek Szyprowski } 308906d3eff6SKirill A. Shutemov } 3090a48d5bdcSStefan Roesch } 309106d3eff6SKirill A. Shutemov 3092b6769834SAlex Shi __split_huge_page(page, list, end); 3093e9b61f19SKirill A. Shutemov ret = 0; 3094baa355fdSKirill A. Shutemov } else { 3095364c1eebSYang Shi spin_unlock(&ds_queue->split_queue_lock); 3096504e070dSYang Shi fail: 3097504e070dSYang Shi if (mapping) 30986b24ca4aSMatthew Wilcox (Oracle) xas_unlock(&xas); 3099b6769834SAlex Shi local_irq_enable(); 31004eecb8b9SMatthew Wilcox (Oracle) remap_page(folio, folio_nr_pages(folio)); 3101fd4a7ac3SBaolin Wang ret = -EAGAIN; 3102e9b61f19SKirill A. Shutemov } 3103e9b61f19SKirill A. Shutemov 3104e9b61f19SKirill A. Shutemov out_unlock: 3105baa355fdSKirill A. Shutemov if (anon_vma) { 3106e9b61f19SKirill A. Shutemov anon_vma_unlock_write(anon_vma); 3107e9b61f19SKirill A. Shutemov put_anon_vma(anon_vma); 3108baa355fdSKirill A. Shutemov } 3109baa355fdSKirill A. Shutemov if (mapping) 3110baa355fdSKirill A. Shutemov i_mmap_unlock_read(mapping); 3111e9b61f19SKirill A. Shutemov out: 311269a37a8bSMatthew Wilcox (Oracle) xas_destroy(&xas); 3113e9b61f19SKirill A. Shutemov count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); 3114e9b61f19SKirill A. Shutemov return ret; 3115e9b61f19SKirill A. Shutemov } 31169a982250SKirill A. Shutemov 31178dc4a8f1SMatthew Wilcox (Oracle) void folio_undo_large_rmappable(struct folio *folio) 31189a982250SKirill A. Shutemov { 31198dc4a8f1SMatthew Wilcox (Oracle) struct deferred_split *ds_queue; 31209a982250SKirill A. Shutemov unsigned long flags; 31219a982250SKirill A. Shutemov 3122deedad80SYin Fengwei /* 3123deedad80SYin Fengwei * At this point, there is no one trying to add the folio to 3124deedad80SYin Fengwei * deferred_list. If folio is not in deferred_list, it's safe 3125deedad80SYin Fengwei * to check without acquiring the split_queue_lock. 3126deedad80SYin Fengwei */ 31278dc4a8f1SMatthew Wilcox (Oracle) if (data_race(list_empty(&folio->_deferred_list))) 31288dc4a8f1SMatthew Wilcox (Oracle) return; 31298dc4a8f1SMatthew Wilcox (Oracle) 31308dc4a8f1SMatthew Wilcox (Oracle) ds_queue = get_deferred_split_queue(folio); 3131364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 31328991de90SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) { 3133364c1eebSYang Shi ds_queue->split_queue_len--; 31348991de90SMatthew Wilcox (Oracle) list_del(&folio->_deferred_list); 31359a982250SKirill A. Shutemov } 3136364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 3137deedad80SYin Fengwei } 31389a982250SKirill A. Shutemov 3139f158ed61SMatthew Wilcox (Oracle) void deferred_split_folio(struct folio *folio) 31409a982250SKirill A. Shutemov { 3141f8baa6beSMatthew Wilcox (Oracle) struct deferred_split *ds_queue = get_deferred_split_queue(folio); 314287eaceb3SYang Shi #ifdef CONFIG_MEMCG 31438991de90SMatthew Wilcox (Oracle) struct mem_cgroup *memcg = folio_memcg(folio); 314487eaceb3SYang Shi #endif 31459a982250SKirill A. Shutemov unsigned long flags; 31469a982250SKirill A. Shutemov 31478991de90SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); 31489a982250SKirill A. Shutemov 314987eaceb3SYang Shi /* 315087eaceb3SYang Shi * The try_to_unmap() in page reclaim path might reach here too, 315187eaceb3SYang Shi * this may cause a race condition to corrupt deferred split queue. 31528991de90SMatthew Wilcox (Oracle) * And, if page reclaim is already handling the same folio, it is 315387eaceb3SYang Shi * unnecessary to handle it again in shrinker. 315487eaceb3SYang Shi * 31558991de90SMatthew Wilcox (Oracle) * Check the swapcache flag to determine if the folio is being 31568991de90SMatthew Wilcox (Oracle) * handled by page reclaim since THP swap would add the folio into 315787eaceb3SYang Shi * swap cache before calling try_to_unmap(). 315887eaceb3SYang Shi */ 31598991de90SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 316087eaceb3SYang Shi return; 316187eaceb3SYang Shi 31628991de90SMatthew Wilcox (Oracle) if (!list_empty(&folio->_deferred_list)) 31639a982250SKirill A. Shutemov return; 31649a982250SKirill A. Shutemov 3165364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 31668991de90SMatthew Wilcox (Oracle) if (list_empty(&folio->_deferred_list)) { 3167f9719a03SKirill A. Shutemov count_vm_event(THP_DEFERRED_SPLIT_PAGE); 31688991de90SMatthew Wilcox (Oracle) list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); 3169364c1eebSYang Shi ds_queue->split_queue_len++; 317087eaceb3SYang Shi #ifdef CONFIG_MEMCG 317187eaceb3SYang Shi if (memcg) 31728991de90SMatthew Wilcox (Oracle) set_shrinker_bit(memcg, folio_nid(folio), 317354d91729SQi Zheng deferred_split_shrinker->id); 317487eaceb3SYang Shi #endif 31759a982250SKirill A. Shutemov } 3176364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 31779a982250SKirill A. Shutemov } 31789a982250SKirill A. Shutemov 31799a982250SKirill A. Shutemov static unsigned long deferred_split_count(struct shrinker *shrink, 31809a982250SKirill A. Shutemov struct shrink_control *sc) 31819a982250SKirill A. Shutemov { 3182a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 3183364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 318487eaceb3SYang Shi 318587eaceb3SYang Shi #ifdef CONFIG_MEMCG 318687eaceb3SYang Shi if (sc->memcg) 318787eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 318887eaceb3SYang Shi #endif 3189364c1eebSYang Shi return READ_ONCE(ds_queue->split_queue_len); 31909a982250SKirill A. Shutemov } 31919a982250SKirill A. Shutemov 31929a982250SKirill A. Shutemov static unsigned long deferred_split_scan(struct shrinker *shrink, 31939a982250SKirill A. Shutemov struct shrink_control *sc) 31949a982250SKirill A. Shutemov { 3195a3d0a918SKirill A. Shutemov struct pglist_data *pgdata = NODE_DATA(sc->nid); 3196364c1eebSYang Shi struct deferred_split *ds_queue = &pgdata->deferred_split_queue; 31979a982250SKirill A. Shutemov unsigned long flags; 31984375a553SMatthew Wilcox (Oracle) LIST_HEAD(list); 31994375a553SMatthew Wilcox (Oracle) struct folio *folio, *next; 32009a982250SKirill A. Shutemov int split = 0; 32019a982250SKirill A. Shutemov 320287eaceb3SYang Shi #ifdef CONFIG_MEMCG 320387eaceb3SYang Shi if (sc->memcg) 320487eaceb3SYang Shi ds_queue = &sc->memcg->deferred_split_queue; 320587eaceb3SYang Shi #endif 320687eaceb3SYang Shi 3207364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 32089a982250SKirill A. Shutemov /* Take pin on all head pages to avoid freeing them under us */ 32094375a553SMatthew Wilcox (Oracle) list_for_each_entry_safe(folio, next, &ds_queue->split_queue, 32104375a553SMatthew Wilcox (Oracle) _deferred_list) { 32114375a553SMatthew Wilcox (Oracle) if (folio_try_get(folio)) { 32124375a553SMatthew Wilcox (Oracle) list_move(&folio->_deferred_list, &list); 3213e3ae1953SKirill A. Shutemov } else { 32144375a553SMatthew Wilcox (Oracle) /* We lost race with folio_put() */ 32154375a553SMatthew Wilcox (Oracle) list_del_init(&folio->_deferred_list); 3216364c1eebSYang Shi ds_queue->split_queue_len--; 32179a982250SKirill A. Shutemov } 3218e3ae1953SKirill A. Shutemov if (!--sc->nr_to_scan) 3219e3ae1953SKirill A. Shutemov break; 32209a982250SKirill A. Shutemov } 3221364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 32229a982250SKirill A. Shutemov 32234375a553SMatthew Wilcox (Oracle) list_for_each_entry_safe(folio, next, &list, _deferred_list) { 32244375a553SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 3225fa41b900SKirill A. Shutemov goto next; 32269a982250SKirill A. Shutemov /* split_huge_page() removes page from list on success */ 32274375a553SMatthew Wilcox (Oracle) if (!split_folio(folio)) 32289a982250SKirill A. Shutemov split++; 32294375a553SMatthew Wilcox (Oracle) folio_unlock(folio); 3230fa41b900SKirill A. Shutemov next: 32314375a553SMatthew Wilcox (Oracle) folio_put(folio); 32329a982250SKirill A. Shutemov } 32339a982250SKirill A. Shutemov 3234364c1eebSYang Shi spin_lock_irqsave(&ds_queue->split_queue_lock, flags); 3235364c1eebSYang Shi list_splice_tail(&list, &ds_queue->split_queue); 3236364c1eebSYang Shi spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); 32379a982250SKirill A. Shutemov 3238cb8d68ecSKirill A. Shutemov /* 3239cb8d68ecSKirill A. Shutemov * Stop shrinker if we didn't split any page, but the queue is empty. 3240cb8d68ecSKirill A. Shutemov * This can happen if pages were freed under us. 3241cb8d68ecSKirill A. Shutemov */ 3242364c1eebSYang Shi if (!split && list_empty(&ds_queue->split_queue)) 3243cb8d68ecSKirill A. Shutemov return SHRINK_STOP; 3244cb8d68ecSKirill A. Shutemov return split; 32459a982250SKirill A. Shutemov } 32469a982250SKirill A. Shutemov 324749071d43SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 3248fa6c0231SZi Yan static void split_huge_pages_all(void) 324949071d43SKirill A. Shutemov { 325049071d43SKirill A. Shutemov struct zone *zone; 325149071d43SKirill A. Shutemov struct page *page; 3252630e7c5eSKefeng Wang struct folio *folio; 325349071d43SKirill A. Shutemov unsigned long pfn, max_zone_pfn; 325449071d43SKirill A. Shutemov unsigned long total = 0, split = 0; 325549071d43SKirill A. Shutemov 3256fa6c0231SZi Yan pr_debug("Split all THPs\n"); 3257a17206daSMiaohe Lin for_each_zone(zone) { 3258a17206daSMiaohe Lin if (!managed_zone(zone)) 3259a17206daSMiaohe Lin continue; 326049071d43SKirill A. Shutemov max_zone_pfn = zone_end_pfn(zone); 326149071d43SKirill A. Shutemov for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { 3262a17206daSMiaohe Lin int nr_pages; 326349071d43SKirill A. Shutemov 32642b7aa91bSNaoya Horiguchi page = pfn_to_online_page(pfn); 3265630e7c5eSKefeng Wang if (!page || PageTail(page)) 3266630e7c5eSKefeng Wang continue; 3267630e7c5eSKefeng Wang folio = page_folio(page); 3268630e7c5eSKefeng Wang if (!folio_try_get(folio)) 326949071d43SKirill A. Shutemov continue; 327049071d43SKirill A. Shutemov 3271630e7c5eSKefeng Wang if (unlikely(page_folio(page) != folio)) 327249071d43SKirill A. Shutemov goto next; 327349071d43SKirill A. Shutemov 3274630e7c5eSKefeng Wang if (zone != folio_zone(folio)) 3275630e7c5eSKefeng Wang goto next; 3276630e7c5eSKefeng Wang 3277630e7c5eSKefeng Wang if (!folio_test_large(folio) 3278630e7c5eSKefeng Wang || folio_test_hugetlb(folio) 3279630e7c5eSKefeng Wang || !folio_test_lru(folio)) 328049071d43SKirill A. Shutemov goto next; 328149071d43SKirill A. Shutemov 328249071d43SKirill A. Shutemov total++; 3283630e7c5eSKefeng Wang folio_lock(folio); 3284630e7c5eSKefeng Wang nr_pages = folio_nr_pages(folio); 3285630e7c5eSKefeng Wang if (!split_folio(folio)) 328649071d43SKirill A. Shutemov split++; 3287a17206daSMiaohe Lin pfn += nr_pages - 1; 3288630e7c5eSKefeng Wang folio_unlock(folio); 328949071d43SKirill A. Shutemov next: 3290630e7c5eSKefeng Wang folio_put(folio); 3291fa6c0231SZi Yan cond_resched(); 329249071d43SKirill A. Shutemov } 329349071d43SKirill A. Shutemov } 329449071d43SKirill A. Shutemov 3295fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 329649071d43SKirill A. Shutemov } 3297fa6c0231SZi Yan 3298fa6c0231SZi Yan static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) 3299fa6c0231SZi Yan { 3300fa6c0231SZi Yan return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || 3301fa6c0231SZi Yan is_vm_hugetlb_page(vma); 3302fa6c0231SZi Yan } 3303fa6c0231SZi Yan 3304fa6c0231SZi Yan static int split_huge_pages_pid(int pid, unsigned long vaddr_start, 3305fa6c0231SZi Yan unsigned long vaddr_end) 3306fa6c0231SZi Yan { 3307fa6c0231SZi Yan int ret = 0; 3308fa6c0231SZi Yan struct task_struct *task; 3309fa6c0231SZi Yan struct mm_struct *mm; 3310fa6c0231SZi Yan unsigned long total = 0, split = 0; 3311fa6c0231SZi Yan unsigned long addr; 3312fa6c0231SZi Yan 3313fa6c0231SZi Yan vaddr_start &= PAGE_MASK; 3314fa6c0231SZi Yan vaddr_end &= PAGE_MASK; 3315fa6c0231SZi Yan 3316fa6c0231SZi Yan /* Find the task_struct from pid */ 3317fa6c0231SZi Yan rcu_read_lock(); 3318fa6c0231SZi Yan task = find_task_by_vpid(pid); 3319fa6c0231SZi Yan if (!task) { 3320fa6c0231SZi Yan rcu_read_unlock(); 3321fa6c0231SZi Yan ret = -ESRCH; 3322fa6c0231SZi Yan goto out; 3323fa6c0231SZi Yan } 3324fa6c0231SZi Yan get_task_struct(task); 3325fa6c0231SZi Yan rcu_read_unlock(); 3326fa6c0231SZi Yan 3327fa6c0231SZi Yan /* Find the mm_struct */ 3328fa6c0231SZi Yan mm = get_task_mm(task); 3329fa6c0231SZi Yan put_task_struct(task); 3330fa6c0231SZi Yan 3331fa6c0231SZi Yan if (!mm) { 3332fa6c0231SZi Yan ret = -EINVAL; 3333fa6c0231SZi Yan goto out; 3334fa6c0231SZi Yan } 3335fa6c0231SZi Yan 3336fa6c0231SZi Yan pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", 3337fa6c0231SZi Yan pid, vaddr_start, vaddr_end); 3338fa6c0231SZi Yan 3339fa6c0231SZi Yan mmap_read_lock(mm); 3340fa6c0231SZi Yan /* 3341fa6c0231SZi Yan * always increase addr by PAGE_SIZE, since we could have a PTE page 3342fa6c0231SZi Yan * table filled with PTE-mapped THPs, each of which is distinct. 3343fa6c0231SZi Yan */ 3344fa6c0231SZi Yan for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { 334574ba2b38SMiaohe Lin struct vm_area_struct *vma = vma_lookup(mm, addr); 3346fa6c0231SZi Yan struct page *page; 3347a644b0abSMatthew Wilcox (Oracle) struct folio *folio; 3348fa6c0231SZi Yan 334974ba2b38SMiaohe Lin if (!vma) 3350fa6c0231SZi Yan break; 3351fa6c0231SZi Yan 3352fa6c0231SZi Yan /* skip special VMA and hugetlb VMA */ 3353fa6c0231SZi Yan if (vma_not_suitable_for_thp_split(vma)) { 3354fa6c0231SZi Yan addr = vma->vm_end; 3355fa6c0231SZi Yan continue; 3356fa6c0231SZi Yan } 3357fa6c0231SZi Yan 3358fa6c0231SZi Yan /* FOLL_DUMP to ignore special (like zero) pages */ 335987d2762eSMiaohe Lin page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); 3360fa6c0231SZi Yan 3361f7091ed6SHaiyue Wang if (IS_ERR_OR_NULL(page)) 3362fa6c0231SZi Yan continue; 3363fa6c0231SZi Yan 3364a644b0abSMatthew Wilcox (Oracle) folio = page_folio(page); 3365a644b0abSMatthew Wilcox (Oracle) if (!is_transparent_hugepage(folio)) 3366fa6c0231SZi Yan goto next; 3367fa6c0231SZi Yan 3368fa6c0231SZi Yan total++; 3369a644b0abSMatthew Wilcox (Oracle) if (!can_split_folio(folio, NULL)) 3370fa6c0231SZi Yan goto next; 3371fa6c0231SZi Yan 3372a644b0abSMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 3373fa6c0231SZi Yan goto next; 3374fa6c0231SZi Yan 3375a644b0abSMatthew Wilcox (Oracle) if (!split_folio(folio)) 3376fa6c0231SZi Yan split++; 3377fa6c0231SZi Yan 3378a644b0abSMatthew Wilcox (Oracle) folio_unlock(folio); 3379fa6c0231SZi Yan next: 3380a644b0abSMatthew Wilcox (Oracle) folio_put(folio); 3381fa6c0231SZi Yan cond_resched(); 3382fa6c0231SZi Yan } 3383fa6c0231SZi Yan mmap_read_unlock(mm); 3384fa6c0231SZi Yan mmput(mm); 3385fa6c0231SZi Yan 3386fa6c0231SZi Yan pr_debug("%lu of %lu THP split\n", split, total); 3387fa6c0231SZi Yan 3388fa6c0231SZi Yan out: 3389fa6c0231SZi Yan return ret; 3390fa6c0231SZi Yan } 3391fa6c0231SZi Yan 3392fbe37501SZi Yan static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, 3393fbe37501SZi Yan pgoff_t off_end) 3394fbe37501SZi Yan { 3395fbe37501SZi Yan struct filename *file; 3396fbe37501SZi Yan struct file *candidate; 3397fbe37501SZi Yan struct address_space *mapping; 3398fbe37501SZi Yan int ret = -EINVAL; 3399fbe37501SZi Yan pgoff_t index; 3400fbe37501SZi Yan int nr_pages = 1; 3401fbe37501SZi Yan unsigned long total = 0, split = 0; 3402fbe37501SZi Yan 3403fbe37501SZi Yan file = getname_kernel(file_path); 3404fbe37501SZi Yan if (IS_ERR(file)) 3405fbe37501SZi Yan return ret; 3406fbe37501SZi Yan 3407fbe37501SZi Yan candidate = file_open_name(file, O_RDONLY, 0); 3408fbe37501SZi Yan if (IS_ERR(candidate)) 3409fbe37501SZi Yan goto out; 3410fbe37501SZi Yan 3411fbe37501SZi Yan pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", 3412fbe37501SZi Yan file_path, off_start, off_end); 3413fbe37501SZi Yan 3414fbe37501SZi Yan mapping = candidate->f_mapping; 3415fbe37501SZi Yan 3416fbe37501SZi Yan for (index = off_start; index < off_end; index += nr_pages) { 34171fb130b2SChristoph Hellwig struct folio *folio = filemap_get_folio(mapping, index); 3418fbe37501SZi Yan 3419fbe37501SZi Yan nr_pages = 1; 342066dabbb6SChristoph Hellwig if (IS_ERR(folio)) 3421fbe37501SZi Yan continue; 3422fbe37501SZi Yan 34239ee2c086SMatthew Wilcox (Oracle) if (!folio_test_large(folio)) 3424fbe37501SZi Yan goto next; 3425fbe37501SZi Yan 3426fbe37501SZi Yan total++; 34279ee2c086SMatthew Wilcox (Oracle) nr_pages = folio_nr_pages(folio); 3428fbe37501SZi Yan 34299ee2c086SMatthew Wilcox (Oracle) if (!folio_trylock(folio)) 3430fbe37501SZi Yan goto next; 3431fbe37501SZi Yan 34329ee2c086SMatthew Wilcox (Oracle) if (!split_folio(folio)) 3433fbe37501SZi Yan split++; 3434fbe37501SZi Yan 34359ee2c086SMatthew Wilcox (Oracle) folio_unlock(folio); 3436fbe37501SZi Yan next: 34379ee2c086SMatthew Wilcox (Oracle) folio_put(folio); 3438fbe37501SZi Yan cond_resched(); 3439fbe37501SZi Yan } 3440fbe37501SZi Yan 3441fbe37501SZi Yan filp_close(candidate, NULL); 3442fbe37501SZi Yan ret = 0; 3443fbe37501SZi Yan 3444fbe37501SZi Yan pr_debug("%lu of %lu file-backed THP split\n", split, total); 3445fbe37501SZi Yan out: 3446fbe37501SZi Yan putname(file); 3447fbe37501SZi Yan return ret; 3448fbe37501SZi Yan } 3449fbe37501SZi Yan 3450fa6c0231SZi Yan #define MAX_INPUT_BUF_SZ 255 3451fa6c0231SZi Yan 3452fa6c0231SZi Yan static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, 3453fa6c0231SZi Yan size_t count, loff_t *ppops) 3454fa6c0231SZi Yan { 3455fa6c0231SZi Yan static DEFINE_MUTEX(split_debug_mutex); 3456fa6c0231SZi Yan ssize_t ret; 3457fbe37501SZi Yan /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ 3458fbe37501SZi Yan char input_buf[MAX_INPUT_BUF_SZ]; 3459fa6c0231SZi Yan int pid; 3460fa6c0231SZi Yan unsigned long vaddr_start, vaddr_end; 3461fa6c0231SZi Yan 3462fa6c0231SZi Yan ret = mutex_lock_interruptible(&split_debug_mutex); 3463fa6c0231SZi Yan if (ret) 3464fa6c0231SZi Yan return ret; 3465fa6c0231SZi Yan 3466fa6c0231SZi Yan ret = -EFAULT; 3467fa6c0231SZi Yan 3468fa6c0231SZi Yan memset(input_buf, 0, MAX_INPUT_BUF_SZ); 3469fa6c0231SZi Yan if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) 3470fa6c0231SZi Yan goto out; 3471fa6c0231SZi Yan 3472fa6c0231SZi Yan input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; 3473fbe37501SZi Yan 3474fbe37501SZi Yan if (input_buf[0] == '/') { 3475fbe37501SZi Yan char *tok; 3476fbe37501SZi Yan char *buf = input_buf; 3477fbe37501SZi Yan char file_path[MAX_INPUT_BUF_SZ]; 3478fbe37501SZi Yan pgoff_t off_start = 0, off_end = 0; 3479fbe37501SZi Yan size_t input_len = strlen(input_buf); 3480fbe37501SZi Yan 3481fbe37501SZi Yan tok = strsep(&buf, ","); 3482fbe37501SZi Yan if (tok) { 34831212e00cSMatthew Wilcox (Oracle) strcpy(file_path, tok); 3484fbe37501SZi Yan } else { 3485fbe37501SZi Yan ret = -EINVAL; 3486fbe37501SZi Yan goto out; 3487fbe37501SZi Yan } 3488fbe37501SZi Yan 3489fbe37501SZi Yan ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); 3490fbe37501SZi Yan if (ret != 2) { 3491fbe37501SZi Yan ret = -EINVAL; 3492fbe37501SZi Yan goto out; 3493fbe37501SZi Yan } 3494fbe37501SZi Yan ret = split_huge_pages_in_file(file_path, off_start, off_end); 3495fbe37501SZi Yan if (!ret) 3496fbe37501SZi Yan ret = input_len; 3497fbe37501SZi Yan 3498fbe37501SZi Yan goto out; 3499fbe37501SZi Yan } 3500fbe37501SZi Yan 3501fa6c0231SZi Yan ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); 3502fa6c0231SZi Yan if (ret == 1 && pid == 1) { 3503fa6c0231SZi Yan split_huge_pages_all(); 3504fa6c0231SZi Yan ret = strlen(input_buf); 3505fa6c0231SZi Yan goto out; 3506fa6c0231SZi Yan } else if (ret != 3) { 3507fa6c0231SZi Yan ret = -EINVAL; 3508fa6c0231SZi Yan goto out; 3509fa6c0231SZi Yan } 3510fa6c0231SZi Yan 3511fa6c0231SZi Yan ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); 3512fa6c0231SZi Yan if (!ret) 3513fa6c0231SZi Yan ret = strlen(input_buf); 3514fa6c0231SZi Yan out: 3515fa6c0231SZi Yan mutex_unlock(&split_debug_mutex); 3516fa6c0231SZi Yan return ret; 3517fa6c0231SZi Yan 3518fa6c0231SZi Yan } 3519fa6c0231SZi Yan 3520fa6c0231SZi Yan static const struct file_operations split_huge_pages_fops = { 3521fa6c0231SZi Yan .owner = THIS_MODULE, 3522fa6c0231SZi Yan .write = split_huge_pages_write, 3523fa6c0231SZi Yan .llseek = no_llseek, 3524fa6c0231SZi Yan }; 352549071d43SKirill A. Shutemov 352649071d43SKirill A. Shutemov static int __init split_huge_pages_debugfs(void) 352749071d43SKirill A. Shutemov { 3528d9f7979cSGreg Kroah-Hartman debugfs_create_file("split_huge_pages", 0200, NULL, NULL, 352949071d43SKirill A. Shutemov &split_huge_pages_fops); 353049071d43SKirill A. Shutemov return 0; 353149071d43SKirill A. Shutemov } 353249071d43SKirill A. Shutemov late_initcall(split_huge_pages_debugfs); 353349071d43SKirill A. Shutemov #endif 3534616b8371SZi Yan 3535616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 35367f5abe60SDavid Hildenbrand int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 3537616b8371SZi Yan struct page *page) 3538616b8371SZi Yan { 3539616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3540616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3541616b8371SZi Yan unsigned long address = pvmw->address; 35426c287605SDavid Hildenbrand bool anon_exclusive; 3543616b8371SZi Yan pmd_t pmdval; 3544616b8371SZi Yan swp_entry_t entry; 3545ab6e3d09SNaoya Horiguchi pmd_t pmdswp; 3546616b8371SZi Yan 3547616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 35487f5abe60SDavid Hildenbrand return 0; 3549616b8371SZi Yan 3550616b8371SZi Yan flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); 35518a8683adSHuang Ying pmdval = pmdp_invalidate(vma, address, pvmw->pmd); 35526c287605SDavid Hildenbrand 3553088b8aa5SDavid Hildenbrand /* See page_try_share_anon_rmap(): invalidate PMD first. */ 35546c287605SDavid Hildenbrand anon_exclusive = PageAnon(page) && PageAnonExclusive(page); 35556c287605SDavid Hildenbrand if (anon_exclusive && page_try_share_anon_rmap(page)) { 35566c287605SDavid Hildenbrand set_pmd_at(mm, address, pvmw->pmd, pmdval); 35577f5abe60SDavid Hildenbrand return -EBUSY; 35586c287605SDavid Hildenbrand } 35596c287605SDavid Hildenbrand 3560616b8371SZi Yan if (pmd_dirty(pmdval)) 3561616b8371SZi Yan set_page_dirty(page); 35624dd845b5SAlistair Popple if (pmd_write(pmdval)) 35634dd845b5SAlistair Popple entry = make_writable_migration_entry(page_to_pfn(page)); 35646c287605SDavid Hildenbrand else if (anon_exclusive) 35656c287605SDavid Hildenbrand entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); 35664dd845b5SAlistair Popple else 35674dd845b5SAlistair Popple entry = make_readable_migration_entry(page_to_pfn(page)); 35682e346877SPeter Xu if (pmd_young(pmdval)) 35692e346877SPeter Xu entry = make_migration_entry_young(entry); 35702e346877SPeter Xu if (pmd_dirty(pmdval)) 35712e346877SPeter Xu entry = make_migration_entry_dirty(entry); 3572ab6e3d09SNaoya Horiguchi pmdswp = swp_entry_to_pmd(entry); 3573ab6e3d09SNaoya Horiguchi if (pmd_soft_dirty(pmdval)) 3574ab6e3d09SNaoya Horiguchi pmdswp = pmd_swp_mksoft_dirty(pmdswp); 357524bf08c4SDavid Hildenbrand if (pmd_uffd_wp(pmdval)) 357624bf08c4SDavid Hildenbrand pmdswp = pmd_swp_mkuffd_wp(pmdswp); 3577ab6e3d09SNaoya Horiguchi set_pmd_at(mm, address, pvmw->pmd, pmdswp); 3578cea86fe2SHugh Dickins page_remove_rmap(page, vma, true); 3579616b8371SZi Yan put_page(page); 3580283fd6feSAnshuman Khandual trace_set_migration_pmd(address, pmd_val(pmdswp)); 35817f5abe60SDavid Hildenbrand 35827f5abe60SDavid Hildenbrand return 0; 3583616b8371SZi Yan } 3584616b8371SZi Yan 3585616b8371SZi Yan void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 3586616b8371SZi Yan { 358714d85a6eSDavid Hildenbrand struct folio *folio = page_folio(new); 3588616b8371SZi Yan struct vm_area_struct *vma = pvmw->vma; 3589616b8371SZi Yan struct mm_struct *mm = vma->vm_mm; 3590616b8371SZi Yan unsigned long address = pvmw->address; 35914fba8f2aSMiaohe Lin unsigned long haddr = address & HPAGE_PMD_MASK; 3592616b8371SZi Yan pmd_t pmde; 3593616b8371SZi Yan swp_entry_t entry; 3594616b8371SZi Yan 3595616b8371SZi Yan if (!(pvmw->pmd && !pvmw->pte)) 3596616b8371SZi Yan return; 3597616b8371SZi Yan 3598616b8371SZi Yan entry = pmd_to_swp_entry(*pvmw->pmd); 359914d85a6eSDavid Hildenbrand folio_get(folio); 36002e346877SPeter Xu pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); 3601ab6e3d09SNaoya Horiguchi if (pmd_swp_soft_dirty(*pvmw->pmd)) 3602ab6e3d09SNaoya Horiguchi pmde = pmd_mksoft_dirty(pmde); 36033c811f78SDavid Hildenbrand if (is_writable_migration_entry(entry)) 3604161e393cSRick Edgecombe pmde = pmd_mkwrite(pmde, vma); 36058f34f1eaSPeter Xu if (pmd_swp_uffd_wp(*pvmw->pmd)) 3606f1eb1bacSPeter Xu pmde = pmd_mkuffd_wp(pmde); 36072e346877SPeter Xu if (!is_migration_entry_young(entry)) 36082e346877SPeter Xu pmde = pmd_mkold(pmde); 36092e346877SPeter Xu /* NOTE: this may contain setting soft-dirty on some archs */ 361014d85a6eSDavid Hildenbrand if (folio_test_dirty(folio) && is_migration_entry_dirty(entry)) 36112e346877SPeter Xu pmde = pmd_mkdirty(pmde); 3612616b8371SZi Yan 361314d85a6eSDavid Hildenbrand if (folio_test_anon(folio)) { 36146c287605SDavid Hildenbrand rmap_t rmap_flags = RMAP_COMPOUND; 36156c287605SDavid Hildenbrand 36166c287605SDavid Hildenbrand if (!is_readable_migration_entry(entry)) 36176c287605SDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 36186c287605SDavid Hildenbrand 36194fba8f2aSMiaohe Lin page_add_anon_rmap(new, vma, haddr, rmap_flags); 36206c287605SDavid Hildenbrand } else { 362114d85a6eSDavid Hildenbrand folio_add_file_rmap_pmd(folio, new, vma); 36226c287605SDavid Hildenbrand } 362314d85a6eSDavid Hildenbrand VM_BUG_ON(pmd_write(pmde) && folio_test_anon(folio) && !PageAnonExclusive(new)); 36244fba8f2aSMiaohe Lin set_pmd_at(mm, haddr, pvmw->pmd, pmde); 36255cbcf225SMuchun Song 36265cbcf225SMuchun Song /* No need to invalidate - it was non-present before */ 3627616b8371SZi Yan update_mmu_cache_pmd(vma, address, pvmw->pmd); 3628283fd6feSAnshuman Khandual trace_remove_migration_pmd(address, pmd_val(pmde)); 3629616b8371SZi Yan } 3630616b8371SZi Yan #endif 3631