1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 2b20a3503SChristoph Lameter /* 314e0f9bcSHugh Dickins * Memory Migration functionality - linux/mm/migrate.c 4b20a3503SChristoph Lameter * 5b20a3503SChristoph Lameter * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter 6b20a3503SChristoph Lameter * 7b20a3503SChristoph Lameter * Page migration was first developed in the context of the memory hotplug 8b20a3503SChristoph Lameter * project. The main authors of the migration code are: 9b20a3503SChristoph Lameter * 10b20a3503SChristoph Lameter * IWAMOTO Toshihiro <iwamoto@valinux.co.jp> 11b20a3503SChristoph Lameter * Hirokazu Takahashi <taka@valinux.co.jp> 12b20a3503SChristoph Lameter * Dave Hansen <haveblue@us.ibm.com> 13cde53535SChristoph Lameter * Christoph Lameter 14b20a3503SChristoph Lameter */ 15b20a3503SChristoph Lameter 16b20a3503SChristoph Lameter #include <linux/migrate.h> 17b95f1b31SPaul Gortmaker #include <linux/export.h> 18b20a3503SChristoph Lameter #include <linux/swap.h> 190697212aSChristoph Lameter #include <linux/swapops.h> 20b20a3503SChristoph Lameter #include <linux/pagemap.h> 21e23ca00bSChristoph Lameter #include <linux/buffer_head.h> 22b20a3503SChristoph Lameter #include <linux/mm_inline.h> 23b488893aSPavel Emelyanov #include <linux/nsproxy.h> 24b20a3503SChristoph Lameter #include <linux/pagevec.h> 25e9995ef9SHugh Dickins #include <linux/ksm.h> 26b20a3503SChristoph Lameter #include <linux/rmap.h> 27b20a3503SChristoph Lameter #include <linux/topology.h> 28b20a3503SChristoph Lameter #include <linux/cpu.h> 29b20a3503SChristoph Lameter #include <linux/cpuset.h> 3004e62a29SChristoph Lameter #include <linux/writeback.h> 31742755a1SChristoph Lameter #include <linux/mempolicy.h> 32742755a1SChristoph Lameter #include <linux/vmalloc.h> 3386c3a764SDavid Quigley #include <linux/security.h> 3442cb14b1SHugh Dickins #include <linux/backing-dev.h> 35bda807d4SMinchan Kim #include <linux/compaction.h> 364f5ca265SAdrian Bunk #include <linux/syscalls.h> 377addf443SDominik Brodowski #include <linux/compat.h> 38290408d4SNaoya Horiguchi #include <linux/hugetlb.h> 398e6ac7faSAneesh Kumar K.V #include <linux/hugetlb_cgroup.h> 405a0e3ad6STejun Heo #include <linux/gfp.h> 41df6ad698SJérôme Glisse #include <linux/pfn_t.h> 42a5430ddaSJérôme Glisse #include <linux/memremap.h> 438315ada7SJérôme Glisse #include <linux/userfaultfd_k.h> 44bf6bddf1SRafael Aquini #include <linux/balloon_compaction.h> 4533c3fc71SVladimir Davydov #include <linux/page_idle.h> 46d435edcaSVlastimil Babka #include <linux/page_owner.h> 476e84f315SIngo Molnar #include <linux/sched/mm.h> 48197e7e52SLinus Torvalds #include <linux/ptrace.h> 4934290e2cSRalph Campbell #include <linux/oom.h> 50884a6e5dSDave Hansen #include <linux/memory.h> 51ac16ec83SBaolin Wang #include <linux/random.h> 52c574bbe9SHuang Ying #include <linux/sched/sysctl.h> 53b20a3503SChristoph Lameter 540d1836c3SMichal Nazarewicz #include <asm/tlbflush.h> 550d1836c3SMichal Nazarewicz 567b2a2d4aSMel Gorman #include <trace/events/migrate.h> 577b2a2d4aSMel Gorman 58b20a3503SChristoph Lameter #include "internal.h" 59b20a3503SChristoph Lameter 609e5bcd61SYisheng Xie int isolate_movable_page(struct page *page, isolate_mode_t mode) 61bda807d4SMinchan Kim { 6268f2736aSMatthew Wilcox (Oracle) const struct movable_operations *mops; 63bda807d4SMinchan Kim 64bda807d4SMinchan Kim /* 65bda807d4SMinchan Kim * Avoid burning cycles with pages that are yet under __free_pages(), 66bda807d4SMinchan Kim * or just got freed under us. 67bda807d4SMinchan Kim * 68bda807d4SMinchan Kim * In case we 'win' a race for a movable page being freed under us and 69bda807d4SMinchan Kim * raise its refcount preventing __free_pages() from doing its job 70bda807d4SMinchan Kim * the put_page() at the end of this block will take care of 71bda807d4SMinchan Kim * release this page, thus avoiding a nasty leakage. 72bda807d4SMinchan Kim */ 73bda807d4SMinchan Kim if (unlikely(!get_page_unless_zero(page))) 74bda807d4SMinchan Kim goto out; 75bda807d4SMinchan Kim 76bda807d4SMinchan Kim /* 77bda807d4SMinchan Kim * Check PageMovable before holding a PG_lock because page's owner 78bda807d4SMinchan Kim * assumes anybody doesn't touch PG_lock of newly allocated page 798bb4e7a2SWei Yang * so unconditionally grabbing the lock ruins page's owner side. 80bda807d4SMinchan Kim */ 81bda807d4SMinchan Kim if (unlikely(!__PageMovable(page))) 82bda807d4SMinchan Kim goto out_putpage; 83bda807d4SMinchan Kim /* 84bda807d4SMinchan Kim * As movable pages are not isolated from LRU lists, concurrent 85bda807d4SMinchan Kim * compaction threads can race against page migration functions 86bda807d4SMinchan Kim * as well as race against the releasing a page. 87bda807d4SMinchan Kim * 88bda807d4SMinchan Kim * In order to avoid having an already isolated movable page 89bda807d4SMinchan Kim * being (wrongly) re-isolated while it is under migration, 90bda807d4SMinchan Kim * or to avoid attempting to isolate pages being released, 91bda807d4SMinchan Kim * lets be sure we have the page lock 92bda807d4SMinchan Kim * before proceeding with the movable page isolation steps. 93bda807d4SMinchan Kim */ 94bda807d4SMinchan Kim if (unlikely(!trylock_page(page))) 95bda807d4SMinchan Kim goto out_putpage; 96bda807d4SMinchan Kim 97bda807d4SMinchan Kim if (!PageMovable(page) || PageIsolated(page)) 98bda807d4SMinchan Kim goto out_no_isolated; 99bda807d4SMinchan Kim 10068f2736aSMatthew Wilcox (Oracle) mops = page_movable_ops(page); 10168f2736aSMatthew Wilcox (Oracle) VM_BUG_ON_PAGE(!mops, page); 102bda807d4SMinchan Kim 10368f2736aSMatthew Wilcox (Oracle) if (!mops->isolate_page(page, mode)) 104bda807d4SMinchan Kim goto out_no_isolated; 105bda807d4SMinchan Kim 106bda807d4SMinchan Kim /* Driver shouldn't use PG_isolated bit of page->flags */ 107bda807d4SMinchan Kim WARN_ON_ONCE(PageIsolated(page)); 108356ea386Sandrew.yang SetPageIsolated(page); 109bda807d4SMinchan Kim unlock_page(page); 110bda807d4SMinchan Kim 1119e5bcd61SYisheng Xie return 0; 112bda807d4SMinchan Kim 113bda807d4SMinchan Kim out_no_isolated: 114bda807d4SMinchan Kim unlock_page(page); 115bda807d4SMinchan Kim out_putpage: 116bda807d4SMinchan Kim put_page(page); 117bda807d4SMinchan Kim out: 1189e5bcd61SYisheng Xie return -EBUSY; 119bda807d4SMinchan Kim } 120bda807d4SMinchan Kim 121606a6f71SMiaohe Lin static void putback_movable_page(struct page *page) 122bda807d4SMinchan Kim { 12368f2736aSMatthew Wilcox (Oracle) const struct movable_operations *mops = page_movable_ops(page); 124bda807d4SMinchan Kim 12568f2736aSMatthew Wilcox (Oracle) mops->putback_page(page); 126356ea386Sandrew.yang ClearPageIsolated(page); 127bda807d4SMinchan Kim } 128bda807d4SMinchan Kim 129b20a3503SChristoph Lameter /* 1305733c7d1SRafael Aquini * Put previously isolated pages back onto the appropriate lists 1315733c7d1SRafael Aquini * from where they were once taken off for compaction/migration. 1325733c7d1SRafael Aquini * 13359c82b70SJoonsoo Kim * This function shall be used whenever the isolated pageset has been 13459c82b70SJoonsoo Kim * built from lru, balloon, hugetlbfs page. See isolate_migratepages_range() 1357ce82f4cSMiaohe Lin * and isolate_hugetlb(). 1365733c7d1SRafael Aquini */ 1375733c7d1SRafael Aquini void putback_movable_pages(struct list_head *l) 1385733c7d1SRafael Aquini { 1395733c7d1SRafael Aquini struct page *page; 1405733c7d1SRafael Aquini struct page *page2; 1415733c7d1SRafael Aquini 1425733c7d1SRafael Aquini list_for_each_entry_safe(page, page2, l, lru) { 14331caf665SNaoya Horiguchi if (unlikely(PageHuge(page))) { 14431caf665SNaoya Horiguchi putback_active_hugepage(page); 14531caf665SNaoya Horiguchi continue; 14631caf665SNaoya Horiguchi } 1475733c7d1SRafael Aquini list_del(&page->lru); 148bda807d4SMinchan Kim /* 149bda807d4SMinchan Kim * We isolated non-lru movable page so here we can use 150bda807d4SMinchan Kim * __PageMovable because LRU page's mapping cannot have 151bda807d4SMinchan Kim * PAGE_MAPPING_MOVABLE. 152bda807d4SMinchan Kim */ 153b1123ea6SMinchan Kim if (unlikely(__PageMovable(page))) { 154bda807d4SMinchan Kim VM_BUG_ON_PAGE(!PageIsolated(page), page); 155bda807d4SMinchan Kim lock_page(page); 156bda807d4SMinchan Kim if (PageMovable(page)) 157bda807d4SMinchan Kim putback_movable_page(page); 158bf6bddf1SRafael Aquini else 159356ea386Sandrew.yang ClearPageIsolated(page); 160bda807d4SMinchan Kim unlock_page(page); 161bda807d4SMinchan Kim put_page(page); 162bda807d4SMinchan Kim } else { 163e8db67ebSNaoya Horiguchi mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + 1646c357848SMatthew Wilcox (Oracle) page_is_file_lru(page), -thp_nr_pages(page)); 165fc280fe8SRabin Vincent putback_lru_page(page); 166b20a3503SChristoph Lameter } 167b20a3503SChristoph Lameter } 168bda807d4SMinchan Kim } 169b20a3503SChristoph Lameter 1700697212aSChristoph Lameter /* 1710697212aSChristoph Lameter * Restore a potential migration pte to a working pte entry 1720697212aSChristoph Lameter */ 1732f031c6fSMatthew Wilcox (Oracle) static bool remove_migration_pte(struct folio *folio, 1742f031c6fSMatthew Wilcox (Oracle) struct vm_area_struct *vma, unsigned long addr, void *old) 1750697212aSChristoph Lameter { 1764eecb8b9SMatthew Wilcox (Oracle) DEFINE_FOLIO_VMA_WALK(pvmw, old, vma, addr, PVMW_SYNC | PVMW_MIGRATION); 1770697212aSChristoph Lameter 1783fe87967SKirill A. Shutemov while (page_vma_mapped_walk(&pvmw)) { 1796c287605SDavid Hildenbrand rmap_t rmap_flags = RMAP_NONE; 1800697212aSChristoph Lameter pte_t pte; 1810697212aSChristoph Lameter swp_entry_t entry; 1824eecb8b9SMatthew Wilcox (Oracle) struct page *new; 1834eecb8b9SMatthew Wilcox (Oracle) unsigned long idx = 0; 1840697212aSChristoph Lameter 1854eecb8b9SMatthew Wilcox (Oracle) /* pgoff is invalid for ksm pages, but they are never large */ 1864eecb8b9SMatthew Wilcox (Oracle) if (folio_test_large(folio) && !folio_test_hugetlb(folio)) 1874eecb8b9SMatthew Wilcox (Oracle) idx = linear_page_index(vma, pvmw.address) - pvmw.pgoff; 1884eecb8b9SMatthew Wilcox (Oracle) new = folio_page(folio, idx); 1890697212aSChristoph Lameter 190616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 191616b8371SZi Yan /* PMD-mapped THP migration entry */ 192616b8371SZi Yan if (!pvmw.pte) { 1934eecb8b9SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_test_hugetlb(folio) || 1944eecb8b9SMatthew Wilcox (Oracle) !folio_test_pmd_mappable(folio), folio); 195616b8371SZi Yan remove_migration_pmd(&pvmw, new); 196616b8371SZi Yan continue; 197616b8371SZi Yan } 198616b8371SZi Yan #endif 199616b8371SZi Yan 2004eecb8b9SMatthew Wilcox (Oracle) folio_get(folio); 201*2e346877SPeter Xu pte = mk_pte(new, READ_ONCE(vma->vm_page_prot)); 2023fe87967SKirill A. Shutemov if (pte_swp_soft_dirty(*pvmw.pte)) 203c3d16e16SCyrill Gorcunov pte = pte_mksoft_dirty(pte); 204d3cb8bf6SMel Gorman 2053fe87967SKirill A. Shutemov /* 2063fe87967SKirill A. Shutemov * Recheck VMA as permissions can change since migration started 2073fe87967SKirill A. Shutemov */ 2083fe87967SKirill A. Shutemov entry = pte_to_swp_entry(*pvmw.pte); 209*2e346877SPeter Xu if (!is_migration_entry_young(entry)) 210*2e346877SPeter Xu pte = pte_mkold(pte); 211*2e346877SPeter Xu if (folio_test_dirty(folio) && is_migration_entry_dirty(entry)) 212*2e346877SPeter Xu pte = pte_mkdirty(pte); 2134dd845b5SAlistair Popple if (is_writable_migration_entry(entry)) 214d3cb8bf6SMel Gorman pte = maybe_mkwrite(pte, vma); 215f45ec5ffSPeter Xu else if (pte_swp_uffd_wp(*pvmw.pte)) 216f45ec5ffSPeter Xu pte = pte_mkuffd_wp(pte); 217d3cb8bf6SMel Gorman 2186c287605SDavid Hildenbrand if (folio_test_anon(folio) && !is_readable_migration_entry(entry)) 2196c287605SDavid Hildenbrand rmap_flags |= RMAP_EXCLUSIVE; 2206c287605SDavid Hildenbrand 2216128763fSRalph Campbell if (unlikely(is_device_private_page(new))) { 2224dd845b5SAlistair Popple if (pte_write(pte)) 2234dd845b5SAlistair Popple entry = make_writable_device_private_entry( 2244dd845b5SAlistair Popple page_to_pfn(new)); 2254dd845b5SAlistair Popple else 2264dd845b5SAlistair Popple entry = make_readable_device_private_entry( 2274dd845b5SAlistair Popple page_to_pfn(new)); 228a5430ddaSJérôme Glisse pte = swp_entry_to_pte(entry); 2293d321bf8SRalph Campbell if (pte_swp_soft_dirty(*pvmw.pte)) 2303d321bf8SRalph Campbell pte = pte_swp_mksoft_dirty(pte); 231f45ec5ffSPeter Xu if (pte_swp_uffd_wp(*pvmw.pte)) 232ebdf8321SAlistair Popple pte = pte_swp_mkuffd_wp(pte); 233df6ad698SJérôme Glisse } 234a5430ddaSJérôme Glisse 2353ef8fd7fSAndi Kleen #ifdef CONFIG_HUGETLB_PAGE 2364eecb8b9SMatthew Wilcox (Oracle) if (folio_test_hugetlb(folio)) { 23779c1c594SChristophe Leroy unsigned int shift = huge_page_shift(hstate_vma(vma)); 23879c1c594SChristophe Leroy 239290408d4SNaoya Horiguchi pte = pte_mkhuge(pte); 24079c1c594SChristophe Leroy pte = arch_make_huge_pte(pte, shift, vma->vm_flags); 2414eecb8b9SMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 24228c5209dSDavid Hildenbrand hugepage_add_anon_rmap(new, vma, pvmw.address, 2436c287605SDavid Hildenbrand rmap_flags); 244290408d4SNaoya Horiguchi else 245fb3d824dSDavid Hildenbrand page_dup_file_rmap(new, true); 2461eba86c0SPasha Tatashin set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); 247383321abSAneesh Kumar K.V } else 248383321abSAneesh Kumar K.V #endif 249383321abSAneesh Kumar K.V { 2504eecb8b9SMatthew Wilcox (Oracle) if (folio_test_anon(folio)) 251f1e2db12SDavid Hildenbrand page_add_anon_rmap(new, vma, pvmw.address, 2526c287605SDavid Hildenbrand rmap_flags); 25304e62a29SChristoph Lameter else 254cea86fe2SHugh Dickins page_add_file_rmap(new, vma, false); 2551eba86c0SPasha Tatashin set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); 256383321abSAneesh Kumar K.V } 257b7435507SHugh Dickins if (vma->vm_flags & VM_LOCKED) 258adb11e78SSebastian Andrzej Siewior mlock_page_drain_local(); 259e125fe40SKirill A. Shutemov 2604cc79b33SAnshuman Khandual trace_remove_migration_pte(pvmw.address, pte_val(pte), 2614cc79b33SAnshuman Khandual compound_order(new)); 2624cc79b33SAnshuman Khandual 26304e62a29SChristoph Lameter /* No need to invalidate - it was non-present before */ 2643fe87967SKirill A. Shutemov update_mmu_cache(vma, pvmw.address, pvmw.pte); 2653fe87967SKirill A. Shutemov } 2663fe87967SKirill A. Shutemov 267e4b82222SMinchan Kim return true; 2680697212aSChristoph Lameter } 2690697212aSChristoph Lameter 2700697212aSChristoph Lameter /* 27104e62a29SChristoph Lameter * Get rid of all migration entries and replace them by 27204e62a29SChristoph Lameter * references to the indicated page. 27304e62a29SChristoph Lameter */ 2744eecb8b9SMatthew Wilcox (Oracle) void remove_migration_ptes(struct folio *src, struct folio *dst, bool locked) 27504e62a29SChristoph Lameter { 276051ac83aSJoonsoo Kim struct rmap_walk_control rwc = { 277051ac83aSJoonsoo Kim .rmap_one = remove_migration_pte, 2784eecb8b9SMatthew Wilcox (Oracle) .arg = src, 279051ac83aSJoonsoo Kim }; 280051ac83aSJoonsoo Kim 281e388466dSKirill A. Shutemov if (locked) 2822f031c6fSMatthew Wilcox (Oracle) rmap_walk_locked(dst, &rwc); 283e388466dSKirill A. Shutemov else 2842f031c6fSMatthew Wilcox (Oracle) rmap_walk(dst, &rwc); 28504e62a29SChristoph Lameter } 28604e62a29SChristoph Lameter 28704e62a29SChristoph Lameter /* 2880697212aSChristoph Lameter * Something used the pte of a page under migration. We need to 2890697212aSChristoph Lameter * get to the page and wait until migration is finished. 2900697212aSChristoph Lameter * When we return from this function the fault will be retried. 2910697212aSChristoph Lameter */ 292e66f17ffSNaoya Horiguchi void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, 29330dad309SNaoya Horiguchi spinlock_t *ptl) 2940697212aSChristoph Lameter { 29530dad309SNaoya Horiguchi pte_t pte; 2960697212aSChristoph Lameter swp_entry_t entry; 2970697212aSChristoph Lameter 29830dad309SNaoya Horiguchi spin_lock(ptl); 2990697212aSChristoph Lameter pte = *ptep; 3000697212aSChristoph Lameter if (!is_swap_pte(pte)) 3010697212aSChristoph Lameter goto out; 3020697212aSChristoph Lameter 3030697212aSChristoph Lameter entry = pte_to_swp_entry(pte); 3040697212aSChristoph Lameter if (!is_migration_entry(entry)) 3050697212aSChristoph Lameter goto out; 3060697212aSChristoph Lameter 307ffa65753SAlistair Popple migration_entry_wait_on_locked(entry, ptep, ptl); 3080697212aSChristoph Lameter return; 3090697212aSChristoph Lameter out: 3100697212aSChristoph Lameter pte_unmap_unlock(ptep, ptl); 3110697212aSChristoph Lameter } 3120697212aSChristoph Lameter 31330dad309SNaoya Horiguchi void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, 31430dad309SNaoya Horiguchi unsigned long address) 31530dad309SNaoya Horiguchi { 31630dad309SNaoya Horiguchi spinlock_t *ptl = pte_lockptr(mm, pmd); 31730dad309SNaoya Horiguchi pte_t *ptep = pte_offset_map(pmd, address); 31830dad309SNaoya Horiguchi __migration_entry_wait(mm, ptep, ptl); 31930dad309SNaoya Horiguchi } 32030dad309SNaoya Horiguchi 321ad1ac596SMiaohe Lin #ifdef CONFIG_HUGETLB_PAGE 322ad1ac596SMiaohe Lin void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl) 32330dad309SNaoya Horiguchi { 324ad1ac596SMiaohe Lin pte_t pte; 325ad1ac596SMiaohe Lin 326ad1ac596SMiaohe Lin spin_lock(ptl); 327ad1ac596SMiaohe Lin pte = huge_ptep_get(ptep); 328ad1ac596SMiaohe Lin 329ad1ac596SMiaohe Lin if (unlikely(!is_hugetlb_entry_migration(pte))) 330ad1ac596SMiaohe Lin spin_unlock(ptl); 331ad1ac596SMiaohe Lin else 332ad1ac596SMiaohe Lin migration_entry_wait_on_locked(pte_to_swp_entry(pte), NULL, ptl); 33330dad309SNaoya Horiguchi } 33430dad309SNaoya Horiguchi 335ad1ac596SMiaohe Lin void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) 336ad1ac596SMiaohe Lin { 337ad1ac596SMiaohe Lin spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), vma->vm_mm, pte); 338ad1ac596SMiaohe Lin 339ad1ac596SMiaohe Lin __migration_entry_wait_huge(pte, ptl); 340ad1ac596SMiaohe Lin } 341ad1ac596SMiaohe Lin #endif 342ad1ac596SMiaohe Lin 343616b8371SZi Yan #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 344616b8371SZi Yan void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd) 345616b8371SZi Yan { 346616b8371SZi Yan spinlock_t *ptl; 347616b8371SZi Yan 348616b8371SZi Yan ptl = pmd_lock(mm, pmd); 349616b8371SZi Yan if (!is_pmd_migration_entry(*pmd)) 350616b8371SZi Yan goto unlock; 351ffa65753SAlistair Popple migration_entry_wait_on_locked(pmd_to_swp_entry(*pmd), NULL, ptl); 352616b8371SZi Yan return; 353616b8371SZi Yan unlock: 354616b8371SZi Yan spin_unlock(ptl); 355616b8371SZi Yan } 356616b8371SZi Yan #endif 357616b8371SZi Yan 358108ca835SMatthew Wilcox (Oracle) static int folio_expected_refs(struct address_space *mapping, 359108ca835SMatthew Wilcox (Oracle) struct folio *folio) 3600b3901b3SJan Kara { 361108ca835SMatthew Wilcox (Oracle) int refs = 1; 362108ca835SMatthew Wilcox (Oracle) if (!mapping) 363108ca835SMatthew Wilcox (Oracle) return refs; 3640b3901b3SJan Kara 365108ca835SMatthew Wilcox (Oracle) refs += folio_nr_pages(folio); 366108ca835SMatthew Wilcox (Oracle) if (folio_test_private(folio)) 367108ca835SMatthew Wilcox (Oracle) refs++; 368108ca835SMatthew Wilcox (Oracle) 369108ca835SMatthew Wilcox (Oracle) return refs; 3700b3901b3SJan Kara } 3710b3901b3SJan Kara 372b20a3503SChristoph Lameter /* 373c3fcf8a5SChristoph Lameter * Replace the page in the mapping. 3745b5c7120SChristoph Lameter * 3755b5c7120SChristoph Lameter * The number of remaining references must be: 3765b5c7120SChristoph Lameter * 1 for anonymous pages without a mapping 3775b5c7120SChristoph Lameter * 2 for pages with a mapping 378266cf658SDavid Howells * 3 for pages with a mapping and PagePrivate/PagePrivate2 set. 379b20a3503SChristoph Lameter */ 3803417013eSMatthew Wilcox (Oracle) int folio_migrate_mapping(struct address_space *mapping, 3813417013eSMatthew Wilcox (Oracle) struct folio *newfolio, struct folio *folio, int extra_count) 382b20a3503SChristoph Lameter { 3833417013eSMatthew Wilcox (Oracle) XA_STATE(xas, &mapping->i_pages, folio_index(folio)); 38442cb14b1SHugh Dickins struct zone *oldzone, *newzone; 38542cb14b1SHugh Dickins int dirty; 386108ca835SMatthew Wilcox (Oracle) int expected_count = folio_expected_refs(mapping, folio) + extra_count; 3873417013eSMatthew Wilcox (Oracle) long nr = folio_nr_pages(folio); 3888763cb45SJérôme Glisse 3896c5240aeSChristoph Lameter if (!mapping) { 3900e8c7d0fSChristoph Lameter /* Anonymous page without mapping */ 3913417013eSMatthew Wilcox (Oracle) if (folio_ref_count(folio) != expected_count) 3926c5240aeSChristoph Lameter return -EAGAIN; 393cf4b769aSHugh Dickins 394cf4b769aSHugh Dickins /* No turning back from here */ 3953417013eSMatthew Wilcox (Oracle) newfolio->index = folio->index; 3963417013eSMatthew Wilcox (Oracle) newfolio->mapping = folio->mapping; 3973417013eSMatthew Wilcox (Oracle) if (folio_test_swapbacked(folio)) 3983417013eSMatthew Wilcox (Oracle) __folio_set_swapbacked(newfolio); 399cf4b769aSHugh Dickins 40078bd5209SRafael Aquini return MIGRATEPAGE_SUCCESS; 4016c5240aeSChristoph Lameter } 4026c5240aeSChristoph Lameter 4033417013eSMatthew Wilcox (Oracle) oldzone = folio_zone(folio); 4043417013eSMatthew Wilcox (Oracle) newzone = folio_zone(newfolio); 40542cb14b1SHugh Dickins 40689eb946aSMatthew Wilcox xas_lock_irq(&xas); 4073417013eSMatthew Wilcox (Oracle) if (!folio_ref_freeze(folio, expected_count)) { 40889eb946aSMatthew Wilcox xas_unlock_irq(&xas); 409e286781dSNick Piggin return -EAGAIN; 410e286781dSNick Piggin } 411e286781dSNick Piggin 412b20a3503SChristoph Lameter /* 4133417013eSMatthew Wilcox (Oracle) * Now we know that no one else is looking at the folio: 414cf4b769aSHugh Dickins * no turning back from here. 415b20a3503SChristoph Lameter */ 4163417013eSMatthew Wilcox (Oracle) newfolio->index = folio->index; 4173417013eSMatthew Wilcox (Oracle) newfolio->mapping = folio->mapping; 4183417013eSMatthew Wilcox (Oracle) folio_ref_add(newfolio, nr); /* add cache reference */ 4193417013eSMatthew Wilcox (Oracle) if (folio_test_swapbacked(folio)) { 4203417013eSMatthew Wilcox (Oracle) __folio_set_swapbacked(newfolio); 4213417013eSMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) { 4223417013eSMatthew Wilcox (Oracle) folio_set_swapcache(newfolio); 4233417013eSMatthew Wilcox (Oracle) newfolio->private = folio_get_private(folio); 424b20a3503SChristoph Lameter } 4256326fec1SNicholas Piggin } else { 4263417013eSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_test_swapcache(folio), folio); 4276326fec1SNicholas Piggin } 428b20a3503SChristoph Lameter 42942cb14b1SHugh Dickins /* Move dirty while page refs frozen and newpage not yet exposed */ 4303417013eSMatthew Wilcox (Oracle) dirty = folio_test_dirty(folio); 43142cb14b1SHugh Dickins if (dirty) { 4323417013eSMatthew Wilcox (Oracle) folio_clear_dirty(folio); 4333417013eSMatthew Wilcox (Oracle) folio_set_dirty(newfolio); 43442cb14b1SHugh Dickins } 43542cb14b1SHugh Dickins 4363417013eSMatthew Wilcox (Oracle) xas_store(&xas, newfolio); 4377cf9c2c7SNick Piggin 4387cf9c2c7SNick Piggin /* 439937a94c9SJacobo Giralt * Drop cache reference from old page by unfreezing 440937a94c9SJacobo Giralt * to one less reference. 4417cf9c2c7SNick Piggin * We know this isn't the last reference. 4427cf9c2c7SNick Piggin */ 4433417013eSMatthew Wilcox (Oracle) folio_ref_unfreeze(folio, expected_count - nr); 4447cf9c2c7SNick Piggin 44589eb946aSMatthew Wilcox xas_unlock(&xas); 44642cb14b1SHugh Dickins /* Leave irq disabled to prevent preemption while updating stats */ 44742cb14b1SHugh Dickins 4480e8c7d0fSChristoph Lameter /* 4490e8c7d0fSChristoph Lameter * If moved to a different zone then also account 4500e8c7d0fSChristoph Lameter * the page for that zone. Other VM counters will be 4510e8c7d0fSChristoph Lameter * taken care of when we establish references to the 4520e8c7d0fSChristoph Lameter * new page and drop references to the old page. 4530e8c7d0fSChristoph Lameter * 4540e8c7d0fSChristoph Lameter * Note that anonymous pages are accounted for 4554b9d0fabSMel Gorman * via NR_FILE_PAGES and NR_ANON_MAPPED if they 4560e8c7d0fSChristoph Lameter * are mapped to swap space. 4570e8c7d0fSChristoph Lameter */ 45842cb14b1SHugh Dickins if (newzone != oldzone) { 4590d1c2072SJohannes Weiner struct lruvec *old_lruvec, *new_lruvec; 4600d1c2072SJohannes Weiner struct mem_cgroup *memcg; 4610d1c2072SJohannes Weiner 4623417013eSMatthew Wilcox (Oracle) memcg = folio_memcg(folio); 4630d1c2072SJohannes Weiner old_lruvec = mem_cgroup_lruvec(memcg, oldzone->zone_pgdat); 4640d1c2072SJohannes Weiner new_lruvec = mem_cgroup_lruvec(memcg, newzone->zone_pgdat); 4650d1c2072SJohannes Weiner 4665c447d27SShakeel Butt __mod_lruvec_state(old_lruvec, NR_FILE_PAGES, -nr); 4675c447d27SShakeel Butt __mod_lruvec_state(new_lruvec, NR_FILE_PAGES, nr); 4683417013eSMatthew Wilcox (Oracle) if (folio_test_swapbacked(folio) && !folio_test_swapcache(folio)) { 4695c447d27SShakeel Butt __mod_lruvec_state(old_lruvec, NR_SHMEM, -nr); 4705c447d27SShakeel Butt __mod_lruvec_state(new_lruvec, NR_SHMEM, nr); 4714b02108aSKOSAKI Motohiro } 472b6038942SShakeel Butt #ifdef CONFIG_SWAP 4733417013eSMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) { 474b6038942SShakeel Butt __mod_lruvec_state(old_lruvec, NR_SWAPCACHE, -nr); 475b6038942SShakeel Butt __mod_lruvec_state(new_lruvec, NR_SWAPCACHE, nr); 476b6038942SShakeel Butt } 477b6038942SShakeel Butt #endif 478f56753acSChristoph Hellwig if (dirty && mapping_can_writeback(mapping)) { 4795c447d27SShakeel Butt __mod_lruvec_state(old_lruvec, NR_FILE_DIRTY, -nr); 4805c447d27SShakeel Butt __mod_zone_page_state(oldzone, NR_ZONE_WRITE_PENDING, -nr); 4815c447d27SShakeel Butt __mod_lruvec_state(new_lruvec, NR_FILE_DIRTY, nr); 4825c447d27SShakeel Butt __mod_zone_page_state(newzone, NR_ZONE_WRITE_PENDING, nr); 48342cb14b1SHugh Dickins } 48442cb14b1SHugh Dickins } 48542cb14b1SHugh Dickins local_irq_enable(); 486b20a3503SChristoph Lameter 48778bd5209SRafael Aquini return MIGRATEPAGE_SUCCESS; 488b20a3503SChristoph Lameter } 4893417013eSMatthew Wilcox (Oracle) EXPORT_SYMBOL(folio_migrate_mapping); 490b20a3503SChristoph Lameter 491b20a3503SChristoph Lameter /* 492290408d4SNaoya Horiguchi * The expected number of remaining references is the same as that 4933417013eSMatthew Wilcox (Oracle) * of folio_migrate_mapping(). 494290408d4SNaoya Horiguchi */ 495290408d4SNaoya Horiguchi int migrate_huge_page_move_mapping(struct address_space *mapping, 496b890ec2aSMatthew Wilcox (Oracle) struct folio *dst, struct folio *src) 497290408d4SNaoya Horiguchi { 498b890ec2aSMatthew Wilcox (Oracle) XA_STATE(xas, &mapping->i_pages, folio_index(src)); 499290408d4SNaoya Horiguchi int expected_count; 500290408d4SNaoya Horiguchi 50189eb946aSMatthew Wilcox xas_lock_irq(&xas); 502b890ec2aSMatthew Wilcox (Oracle) expected_count = 2 + folio_has_private(src); 503b890ec2aSMatthew Wilcox (Oracle) if (!folio_ref_freeze(src, expected_count)) { 50489eb946aSMatthew Wilcox xas_unlock_irq(&xas); 505290408d4SNaoya Horiguchi return -EAGAIN; 506290408d4SNaoya Horiguchi } 507290408d4SNaoya Horiguchi 508b890ec2aSMatthew Wilcox (Oracle) dst->index = src->index; 509b890ec2aSMatthew Wilcox (Oracle) dst->mapping = src->mapping; 5106a93ca8fSJohannes Weiner 511b890ec2aSMatthew Wilcox (Oracle) folio_get(dst); 512290408d4SNaoya Horiguchi 513b890ec2aSMatthew Wilcox (Oracle) xas_store(&xas, dst); 514290408d4SNaoya Horiguchi 515b890ec2aSMatthew Wilcox (Oracle) folio_ref_unfreeze(src, expected_count - 1); 516290408d4SNaoya Horiguchi 51789eb946aSMatthew Wilcox xas_unlock_irq(&xas); 5186a93ca8fSJohannes Weiner 51978bd5209SRafael Aquini return MIGRATEPAGE_SUCCESS; 520290408d4SNaoya Horiguchi } 521290408d4SNaoya Horiguchi 522290408d4SNaoya Horiguchi /* 52319138349SMatthew Wilcox (Oracle) * Copy the flags and some other ancillary information 524b20a3503SChristoph Lameter */ 52519138349SMatthew Wilcox (Oracle) void folio_migrate_flags(struct folio *newfolio, struct folio *folio) 526b20a3503SChristoph Lameter { 5277851a45cSRik van Riel int cpupid; 5287851a45cSRik van Riel 52919138349SMatthew Wilcox (Oracle) if (folio_test_error(folio)) 53019138349SMatthew Wilcox (Oracle) folio_set_error(newfolio); 53119138349SMatthew Wilcox (Oracle) if (folio_test_referenced(folio)) 53219138349SMatthew Wilcox (Oracle) folio_set_referenced(newfolio); 53319138349SMatthew Wilcox (Oracle) if (folio_test_uptodate(folio)) 53419138349SMatthew Wilcox (Oracle) folio_mark_uptodate(newfolio); 53519138349SMatthew Wilcox (Oracle) if (folio_test_clear_active(folio)) { 53619138349SMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(folio_test_unevictable(folio), folio); 53719138349SMatthew Wilcox (Oracle) folio_set_active(newfolio); 53819138349SMatthew Wilcox (Oracle) } else if (folio_test_clear_unevictable(folio)) 53919138349SMatthew Wilcox (Oracle) folio_set_unevictable(newfolio); 54019138349SMatthew Wilcox (Oracle) if (folio_test_workingset(folio)) 54119138349SMatthew Wilcox (Oracle) folio_set_workingset(newfolio); 54219138349SMatthew Wilcox (Oracle) if (folio_test_checked(folio)) 54319138349SMatthew Wilcox (Oracle) folio_set_checked(newfolio); 5446c287605SDavid Hildenbrand /* 5456c287605SDavid Hildenbrand * PG_anon_exclusive (-> PG_mappedtodisk) is always migrated via 5466c287605SDavid Hildenbrand * migration entries. We can still have PG_anon_exclusive set on an 5476c287605SDavid Hildenbrand * effectively unmapped and unreferenced first sub-pages of an 5486c287605SDavid Hildenbrand * anonymous THP: we can simply copy it here via PG_mappedtodisk. 5496c287605SDavid Hildenbrand */ 55019138349SMatthew Wilcox (Oracle) if (folio_test_mappedtodisk(folio)) 55119138349SMatthew Wilcox (Oracle) folio_set_mappedtodisk(newfolio); 552b20a3503SChristoph Lameter 5533417013eSMatthew Wilcox (Oracle) /* Move dirty on pages not done by folio_migrate_mapping() */ 55419138349SMatthew Wilcox (Oracle) if (folio_test_dirty(folio)) 55519138349SMatthew Wilcox (Oracle) folio_set_dirty(newfolio); 556b20a3503SChristoph Lameter 55719138349SMatthew Wilcox (Oracle) if (folio_test_young(folio)) 55819138349SMatthew Wilcox (Oracle) folio_set_young(newfolio); 55919138349SMatthew Wilcox (Oracle) if (folio_test_idle(folio)) 56019138349SMatthew Wilcox (Oracle) folio_set_idle(newfolio); 56133c3fc71SVladimir Davydov 5627851a45cSRik van Riel /* 5637851a45cSRik van Riel * Copy NUMA information to the new page, to prevent over-eager 5647851a45cSRik van Riel * future migrations of this same page. 5657851a45cSRik van Riel */ 56619138349SMatthew Wilcox (Oracle) cpupid = page_cpupid_xchg_last(&folio->page, -1); 56733024536SHuang Ying /* 56833024536SHuang Ying * For memory tiering mode, when migrate between slow and fast 56933024536SHuang Ying * memory node, reset cpupid, because that is used to record 57033024536SHuang Ying * page access time in slow memory node. 57133024536SHuang Ying */ 57233024536SHuang Ying if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) { 57333024536SHuang Ying bool f_toptier = node_is_toptier(page_to_nid(&folio->page)); 57433024536SHuang Ying bool t_toptier = node_is_toptier(page_to_nid(&newfolio->page)); 57533024536SHuang Ying 57633024536SHuang Ying if (f_toptier != t_toptier) 57733024536SHuang Ying cpupid = -1; 57833024536SHuang Ying } 57919138349SMatthew Wilcox (Oracle) page_cpupid_xchg_last(&newfolio->page, cpupid); 5807851a45cSRik van Riel 58119138349SMatthew Wilcox (Oracle) folio_migrate_ksm(newfolio, folio); 582c8d6553bSHugh Dickins /* 583c8d6553bSHugh Dickins * Please do not reorder this without considering how mm/ksm.c's 584c8d6553bSHugh Dickins * get_ksm_page() depends upon ksm_migrate_page() and PageSwapCache(). 585c8d6553bSHugh Dickins */ 58619138349SMatthew Wilcox (Oracle) if (folio_test_swapcache(folio)) 58719138349SMatthew Wilcox (Oracle) folio_clear_swapcache(folio); 58819138349SMatthew Wilcox (Oracle) folio_clear_private(folio); 589ad2fa371SMuchun Song 590ad2fa371SMuchun Song /* page->private contains hugetlb specific flags */ 59119138349SMatthew Wilcox (Oracle) if (!folio_test_hugetlb(folio)) 59219138349SMatthew Wilcox (Oracle) folio->private = NULL; 593b20a3503SChristoph Lameter 594b20a3503SChristoph Lameter /* 595b20a3503SChristoph Lameter * If any waiters have accumulated on the new page then 596b20a3503SChristoph Lameter * wake them up. 597b20a3503SChristoph Lameter */ 59819138349SMatthew Wilcox (Oracle) if (folio_test_writeback(newfolio)) 59919138349SMatthew Wilcox (Oracle) folio_end_writeback(newfolio); 600d435edcaSVlastimil Babka 6016aeff241SYang Shi /* 6026aeff241SYang Shi * PG_readahead shares the same bit with PG_reclaim. The above 6036aeff241SYang Shi * end_page_writeback() may clear PG_readahead mistakenly, so set the 6046aeff241SYang Shi * bit after that. 6056aeff241SYang Shi */ 60619138349SMatthew Wilcox (Oracle) if (folio_test_readahead(folio)) 60719138349SMatthew Wilcox (Oracle) folio_set_readahead(newfolio); 6086aeff241SYang Shi 60919138349SMatthew Wilcox (Oracle) folio_copy_owner(newfolio, folio); 61074485cf2SJohannes Weiner 61119138349SMatthew Wilcox (Oracle) if (!folio_test_hugetlb(folio)) 612d21bba2bSMatthew Wilcox (Oracle) mem_cgroup_migrate(folio, newfolio); 613b20a3503SChristoph Lameter } 61419138349SMatthew Wilcox (Oracle) EXPORT_SYMBOL(folio_migrate_flags); 6152916ecc0SJérôme Glisse 616715cbfd6SMatthew Wilcox (Oracle) void folio_migrate_copy(struct folio *newfolio, struct folio *folio) 6172916ecc0SJérôme Glisse { 618715cbfd6SMatthew Wilcox (Oracle) folio_copy(newfolio, folio); 619715cbfd6SMatthew Wilcox (Oracle) folio_migrate_flags(newfolio, folio); 6202916ecc0SJérôme Glisse } 621715cbfd6SMatthew Wilcox (Oracle) EXPORT_SYMBOL(folio_migrate_copy); 622b20a3503SChristoph Lameter 6231d8b85ccSChristoph Lameter /************************************************************ 6241d8b85ccSChristoph Lameter * Migration functions 6251d8b85ccSChristoph Lameter ***********************************************************/ 6261d8b85ccSChristoph Lameter 62754184650SMatthew Wilcox (Oracle) /** 62854184650SMatthew Wilcox (Oracle) * migrate_folio() - Simple folio migration. 62954184650SMatthew Wilcox (Oracle) * @mapping: The address_space containing the folio. 63054184650SMatthew Wilcox (Oracle) * @dst: The folio to migrate the data to. 63154184650SMatthew Wilcox (Oracle) * @src: The folio containing the current data. 63254184650SMatthew Wilcox (Oracle) * @mode: How to migrate the page. 633b20a3503SChristoph Lameter * 63454184650SMatthew Wilcox (Oracle) * Common logic to directly migrate a single LRU folio suitable for 63554184650SMatthew Wilcox (Oracle) * folios that do not use PagePrivate/PagePrivate2. 63654184650SMatthew Wilcox (Oracle) * 63754184650SMatthew Wilcox (Oracle) * Folios are locked upon entry and exit. 638b20a3503SChristoph Lameter */ 63954184650SMatthew Wilcox (Oracle) int migrate_folio(struct address_space *mapping, struct folio *dst, 64054184650SMatthew Wilcox (Oracle) struct folio *src, enum migrate_mode mode) 641b20a3503SChristoph Lameter { 642b20a3503SChristoph Lameter int rc; 643b20a3503SChristoph Lameter 64454184650SMatthew Wilcox (Oracle) BUG_ON(folio_test_writeback(src)); /* Writeback must be complete */ 645b20a3503SChristoph Lameter 64654184650SMatthew Wilcox (Oracle) rc = folio_migrate_mapping(mapping, dst, src, 0); 647b20a3503SChristoph Lameter 64878bd5209SRafael Aquini if (rc != MIGRATEPAGE_SUCCESS) 649b20a3503SChristoph Lameter return rc; 650b20a3503SChristoph Lameter 6512916ecc0SJérôme Glisse if (mode != MIGRATE_SYNC_NO_COPY) 65254184650SMatthew Wilcox (Oracle) folio_migrate_copy(dst, src); 6532916ecc0SJérôme Glisse else 65454184650SMatthew Wilcox (Oracle) folio_migrate_flags(dst, src); 65578bd5209SRafael Aquini return MIGRATEPAGE_SUCCESS; 656b20a3503SChristoph Lameter } 65754184650SMatthew Wilcox (Oracle) EXPORT_SYMBOL(migrate_folio); 658b20a3503SChristoph Lameter 6599361401eSDavid Howells #ifdef CONFIG_BLOCK 66084ade7c1SJan Kara /* Returns true if all buffers are successfully locked */ 66184ade7c1SJan Kara static bool buffer_migrate_lock_buffers(struct buffer_head *head, 66284ade7c1SJan Kara enum migrate_mode mode) 66384ade7c1SJan Kara { 66484ade7c1SJan Kara struct buffer_head *bh = head; 66584ade7c1SJan Kara 66684ade7c1SJan Kara /* Simple case, sync compaction */ 66784ade7c1SJan Kara if (mode != MIGRATE_ASYNC) { 66884ade7c1SJan Kara do { 66984ade7c1SJan Kara lock_buffer(bh); 67084ade7c1SJan Kara bh = bh->b_this_page; 67184ade7c1SJan Kara 67284ade7c1SJan Kara } while (bh != head); 67384ade7c1SJan Kara 67484ade7c1SJan Kara return true; 67584ade7c1SJan Kara } 67684ade7c1SJan Kara 67784ade7c1SJan Kara /* async case, we cannot block on lock_buffer so use trylock_buffer */ 67884ade7c1SJan Kara do { 67984ade7c1SJan Kara if (!trylock_buffer(bh)) { 68084ade7c1SJan Kara /* 68184ade7c1SJan Kara * We failed to lock the buffer and cannot stall in 68284ade7c1SJan Kara * async migration. Release the taken locks 68384ade7c1SJan Kara */ 68484ade7c1SJan Kara struct buffer_head *failed_bh = bh; 68584ade7c1SJan Kara bh = head; 68684ade7c1SJan Kara while (bh != failed_bh) { 68784ade7c1SJan Kara unlock_buffer(bh); 68884ade7c1SJan Kara bh = bh->b_this_page; 68984ade7c1SJan Kara } 69084ade7c1SJan Kara return false; 69184ade7c1SJan Kara } 69284ade7c1SJan Kara 69384ade7c1SJan Kara bh = bh->b_this_page; 69484ade7c1SJan Kara } while (bh != head); 69584ade7c1SJan Kara return true; 69684ade7c1SJan Kara } 69784ade7c1SJan Kara 69867235182SMatthew Wilcox (Oracle) static int __buffer_migrate_folio(struct address_space *mapping, 69967235182SMatthew Wilcox (Oracle) struct folio *dst, struct folio *src, enum migrate_mode mode, 70089cb0888SJan Kara bool check_refs) 7011d8b85ccSChristoph Lameter { 7021d8b85ccSChristoph Lameter struct buffer_head *bh, *head; 7031d8b85ccSChristoph Lameter int rc; 704cc4f11e6SJan Kara int expected_count; 7051d8b85ccSChristoph Lameter 70667235182SMatthew Wilcox (Oracle) head = folio_buffers(src); 70767235182SMatthew Wilcox (Oracle) if (!head) 70854184650SMatthew Wilcox (Oracle) return migrate_folio(mapping, dst, src, mode); 7091d8b85ccSChristoph Lameter 710cc4f11e6SJan Kara /* Check whether page does not have extra refs before we do more work */ 711108ca835SMatthew Wilcox (Oracle) expected_count = folio_expected_refs(mapping, src); 71267235182SMatthew Wilcox (Oracle) if (folio_ref_count(src) != expected_count) 713cc4f11e6SJan Kara return -EAGAIN; 714cc4f11e6SJan Kara 715cc4f11e6SJan Kara if (!buffer_migrate_lock_buffers(head, mode)) 716cc4f11e6SJan Kara return -EAGAIN; 7171d8b85ccSChristoph Lameter 71889cb0888SJan Kara if (check_refs) { 71989cb0888SJan Kara bool busy; 72089cb0888SJan Kara bool invalidated = false; 72189cb0888SJan Kara 72289cb0888SJan Kara recheck_buffers: 72389cb0888SJan Kara busy = false; 72489cb0888SJan Kara spin_lock(&mapping->private_lock); 72589cb0888SJan Kara bh = head; 72689cb0888SJan Kara do { 72789cb0888SJan Kara if (atomic_read(&bh->b_count)) { 72889cb0888SJan Kara busy = true; 72989cb0888SJan Kara break; 73089cb0888SJan Kara } 73189cb0888SJan Kara bh = bh->b_this_page; 73289cb0888SJan Kara } while (bh != head); 73389cb0888SJan Kara if (busy) { 73489cb0888SJan Kara if (invalidated) { 73589cb0888SJan Kara rc = -EAGAIN; 73689cb0888SJan Kara goto unlock_buffers; 73789cb0888SJan Kara } 738ebdf4de5SJan Kara spin_unlock(&mapping->private_lock); 73989cb0888SJan Kara invalidate_bh_lrus(); 74089cb0888SJan Kara invalidated = true; 74189cb0888SJan Kara goto recheck_buffers; 74289cb0888SJan Kara } 74389cb0888SJan Kara } 74489cb0888SJan Kara 74567235182SMatthew Wilcox (Oracle) rc = folio_migrate_mapping(mapping, dst, src, 0); 74678bd5209SRafael Aquini if (rc != MIGRATEPAGE_SUCCESS) 747cc4f11e6SJan Kara goto unlock_buffers; 7481d8b85ccSChristoph Lameter 74967235182SMatthew Wilcox (Oracle) folio_attach_private(dst, folio_detach_private(src)); 7501d8b85ccSChristoph Lameter 7511d8b85ccSChristoph Lameter bh = head; 7521d8b85ccSChristoph Lameter do { 75367235182SMatthew Wilcox (Oracle) set_bh_page(bh, &dst->page, bh_offset(bh)); 7541d8b85ccSChristoph Lameter bh = bh->b_this_page; 7551d8b85ccSChristoph Lameter } while (bh != head); 7561d8b85ccSChristoph Lameter 7572916ecc0SJérôme Glisse if (mode != MIGRATE_SYNC_NO_COPY) 75867235182SMatthew Wilcox (Oracle) folio_migrate_copy(dst, src); 7592916ecc0SJérôme Glisse else 76067235182SMatthew Wilcox (Oracle) folio_migrate_flags(dst, src); 7611d8b85ccSChristoph Lameter 762cc4f11e6SJan Kara rc = MIGRATEPAGE_SUCCESS; 763cc4f11e6SJan Kara unlock_buffers: 764ebdf4de5SJan Kara if (check_refs) 765ebdf4de5SJan Kara spin_unlock(&mapping->private_lock); 7661d8b85ccSChristoph Lameter bh = head; 7671d8b85ccSChristoph Lameter do { 7681d8b85ccSChristoph Lameter unlock_buffer(bh); 7691d8b85ccSChristoph Lameter bh = bh->b_this_page; 7701d8b85ccSChristoph Lameter } while (bh != head); 7711d8b85ccSChristoph Lameter 772cc4f11e6SJan Kara return rc; 7731d8b85ccSChristoph Lameter } 77489cb0888SJan Kara 77567235182SMatthew Wilcox (Oracle) /** 77667235182SMatthew Wilcox (Oracle) * buffer_migrate_folio() - Migration function for folios with buffers. 77767235182SMatthew Wilcox (Oracle) * @mapping: The address space containing @src. 77867235182SMatthew Wilcox (Oracle) * @dst: The folio to migrate to. 77967235182SMatthew Wilcox (Oracle) * @src: The folio to migrate from. 78067235182SMatthew Wilcox (Oracle) * @mode: How to migrate the folio. 78167235182SMatthew Wilcox (Oracle) * 78267235182SMatthew Wilcox (Oracle) * This function can only be used if the underlying filesystem guarantees 78367235182SMatthew Wilcox (Oracle) * that no other references to @src exist. For example attached buffer 78467235182SMatthew Wilcox (Oracle) * heads are accessed only under the folio lock. If your filesystem cannot 78567235182SMatthew Wilcox (Oracle) * provide this guarantee, buffer_migrate_folio_norefs() may be more 78667235182SMatthew Wilcox (Oracle) * appropriate. 78767235182SMatthew Wilcox (Oracle) * 78867235182SMatthew Wilcox (Oracle) * Return: 0 on success or a negative errno on failure. 78989cb0888SJan Kara */ 79067235182SMatthew Wilcox (Oracle) int buffer_migrate_folio(struct address_space *mapping, 79167235182SMatthew Wilcox (Oracle) struct folio *dst, struct folio *src, enum migrate_mode mode) 79289cb0888SJan Kara { 79367235182SMatthew Wilcox (Oracle) return __buffer_migrate_folio(mapping, dst, src, mode, false); 79489cb0888SJan Kara } 79567235182SMatthew Wilcox (Oracle) EXPORT_SYMBOL(buffer_migrate_folio); 79689cb0888SJan Kara 79767235182SMatthew Wilcox (Oracle) /** 79867235182SMatthew Wilcox (Oracle) * buffer_migrate_folio_norefs() - Migration function for folios with buffers. 79967235182SMatthew Wilcox (Oracle) * @mapping: The address space containing @src. 80067235182SMatthew Wilcox (Oracle) * @dst: The folio to migrate to. 80167235182SMatthew Wilcox (Oracle) * @src: The folio to migrate from. 80267235182SMatthew Wilcox (Oracle) * @mode: How to migrate the folio. 80367235182SMatthew Wilcox (Oracle) * 80467235182SMatthew Wilcox (Oracle) * Like buffer_migrate_folio() except that this variant is more careful 80567235182SMatthew Wilcox (Oracle) * and checks that there are also no buffer head references. This function 80667235182SMatthew Wilcox (Oracle) * is the right one for mappings where buffer heads are directly looked 80767235182SMatthew Wilcox (Oracle) * up and referenced (such as block device mappings). 80867235182SMatthew Wilcox (Oracle) * 80967235182SMatthew Wilcox (Oracle) * Return: 0 on success or a negative errno on failure. 81089cb0888SJan Kara */ 81167235182SMatthew Wilcox (Oracle) int buffer_migrate_folio_norefs(struct address_space *mapping, 81267235182SMatthew Wilcox (Oracle) struct folio *dst, struct folio *src, enum migrate_mode mode) 81389cb0888SJan Kara { 81467235182SMatthew Wilcox (Oracle) return __buffer_migrate_folio(mapping, dst, src, mode, true); 81589cb0888SJan Kara } 8169361401eSDavid Howells #endif 8171d8b85ccSChristoph Lameter 8182ec810d5SMatthew Wilcox (Oracle) int filemap_migrate_folio(struct address_space *mapping, 8192ec810d5SMatthew Wilcox (Oracle) struct folio *dst, struct folio *src, enum migrate_mode mode) 8202ec810d5SMatthew Wilcox (Oracle) { 8212ec810d5SMatthew Wilcox (Oracle) int ret; 8222ec810d5SMatthew Wilcox (Oracle) 8232ec810d5SMatthew Wilcox (Oracle) ret = folio_migrate_mapping(mapping, dst, src, 0); 8242ec810d5SMatthew Wilcox (Oracle) if (ret != MIGRATEPAGE_SUCCESS) 8252ec810d5SMatthew Wilcox (Oracle) return ret; 8262ec810d5SMatthew Wilcox (Oracle) 8272ec810d5SMatthew Wilcox (Oracle) if (folio_get_private(src)) 8282ec810d5SMatthew Wilcox (Oracle) folio_attach_private(dst, folio_detach_private(src)); 8292ec810d5SMatthew Wilcox (Oracle) 8302ec810d5SMatthew Wilcox (Oracle) if (mode != MIGRATE_SYNC_NO_COPY) 8312ec810d5SMatthew Wilcox (Oracle) folio_migrate_copy(dst, src); 8322ec810d5SMatthew Wilcox (Oracle) else 8332ec810d5SMatthew Wilcox (Oracle) folio_migrate_flags(dst, src); 8342ec810d5SMatthew Wilcox (Oracle) return MIGRATEPAGE_SUCCESS; 8352ec810d5SMatthew Wilcox (Oracle) } 8362ec810d5SMatthew Wilcox (Oracle) EXPORT_SYMBOL_GPL(filemap_migrate_folio); 8372ec810d5SMatthew Wilcox (Oracle) 83804e62a29SChristoph Lameter /* 8392be7fa10SMatthew Wilcox (Oracle) * Writeback a folio to clean the dirty state 84004e62a29SChristoph Lameter */ 8412be7fa10SMatthew Wilcox (Oracle) static int writeout(struct address_space *mapping, struct folio *folio) 84204e62a29SChristoph Lameter { 84304e62a29SChristoph Lameter struct writeback_control wbc = { 84404e62a29SChristoph Lameter .sync_mode = WB_SYNC_NONE, 84504e62a29SChristoph Lameter .nr_to_write = 1, 84604e62a29SChristoph Lameter .range_start = 0, 84704e62a29SChristoph Lameter .range_end = LLONG_MAX, 84804e62a29SChristoph Lameter .for_reclaim = 1 84904e62a29SChristoph Lameter }; 85004e62a29SChristoph Lameter int rc; 85104e62a29SChristoph Lameter 85204e62a29SChristoph Lameter if (!mapping->a_ops->writepage) 85304e62a29SChristoph Lameter /* No write method for the address space */ 85404e62a29SChristoph Lameter return -EINVAL; 85504e62a29SChristoph Lameter 8562be7fa10SMatthew Wilcox (Oracle) if (!folio_clear_dirty_for_io(folio)) 85704e62a29SChristoph Lameter /* Someone else already triggered a write */ 85804e62a29SChristoph Lameter return -EAGAIN; 85904e62a29SChristoph Lameter 86004e62a29SChristoph Lameter /* 8612be7fa10SMatthew Wilcox (Oracle) * A dirty folio may imply that the underlying filesystem has 8622be7fa10SMatthew Wilcox (Oracle) * the folio on some queue. So the folio must be clean for 8632be7fa10SMatthew Wilcox (Oracle) * migration. Writeout may mean we lose the lock and the 8642be7fa10SMatthew Wilcox (Oracle) * folio state is no longer what we checked for earlier. 86504e62a29SChristoph Lameter * At this point we know that the migration attempt cannot 86604e62a29SChristoph Lameter * be successful. 86704e62a29SChristoph Lameter */ 8684eecb8b9SMatthew Wilcox (Oracle) remove_migration_ptes(folio, folio, false); 86904e62a29SChristoph Lameter 8702be7fa10SMatthew Wilcox (Oracle) rc = mapping->a_ops->writepage(&folio->page, &wbc); 87104e62a29SChristoph Lameter 87204e62a29SChristoph Lameter if (rc != AOP_WRITEPAGE_ACTIVATE) 87304e62a29SChristoph Lameter /* unlocked. Relock */ 8742be7fa10SMatthew Wilcox (Oracle) folio_lock(folio); 87504e62a29SChristoph Lameter 876bda8550dSHugh Dickins return (rc < 0) ? -EIO : -EAGAIN; 87704e62a29SChristoph Lameter } 87804e62a29SChristoph Lameter 87904e62a29SChristoph Lameter /* 88004e62a29SChristoph Lameter * Default handling if a filesystem does not provide a migration function. 88104e62a29SChristoph Lameter */ 8828faa8ef5SMatthew Wilcox (Oracle) static int fallback_migrate_folio(struct address_space *mapping, 8838faa8ef5SMatthew Wilcox (Oracle) struct folio *dst, struct folio *src, enum migrate_mode mode) 8848351a6e4SChristoph Lameter { 8858faa8ef5SMatthew Wilcox (Oracle) if (folio_test_dirty(src)) { 8868faa8ef5SMatthew Wilcox (Oracle) /* Only writeback folios in full synchronous migration */ 8872916ecc0SJérôme Glisse switch (mode) { 8882916ecc0SJérôme Glisse case MIGRATE_SYNC: 8892916ecc0SJérôme Glisse case MIGRATE_SYNC_NO_COPY: 8902916ecc0SJérôme Glisse break; 8912916ecc0SJérôme Glisse default: 892b969c4abSMel Gorman return -EBUSY; 8932916ecc0SJérôme Glisse } 8942be7fa10SMatthew Wilcox (Oracle) return writeout(mapping, src); 895b969c4abSMel Gorman } 8968351a6e4SChristoph Lameter 8978351a6e4SChristoph Lameter /* 8988351a6e4SChristoph Lameter * Buffers may be managed in a filesystem specific way. 8998351a6e4SChristoph Lameter * We must have no buffers or drop them. 9008351a6e4SChristoph Lameter */ 9018faa8ef5SMatthew Wilcox (Oracle) if (folio_test_private(src) && 9028faa8ef5SMatthew Wilcox (Oracle) !filemap_release_folio(src, GFP_KERNEL)) 903806031bbSMel Gorman return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY; 9048351a6e4SChristoph Lameter 90554184650SMatthew Wilcox (Oracle) return migrate_folio(mapping, dst, src, mode); 9068351a6e4SChristoph Lameter } 9078351a6e4SChristoph Lameter 9081d8b85ccSChristoph Lameter /* 909e24f0b8fSChristoph Lameter * Move a page to a newly allocated page 910e24f0b8fSChristoph Lameter * The page is locked and all ptes have been successfully removed. 911b20a3503SChristoph Lameter * 912e24f0b8fSChristoph Lameter * The new page will have replaced the old page if this function 913e24f0b8fSChristoph Lameter * is successful. 914894bc310SLee Schermerhorn * 915894bc310SLee Schermerhorn * Return value: 916894bc310SLee Schermerhorn * < 0 - error code 91778bd5209SRafael Aquini * MIGRATEPAGE_SUCCESS - success 918b20a3503SChristoph Lameter */ 919e7e3ffebSMatthew Wilcox (Oracle) static int move_to_new_folio(struct folio *dst, struct folio *src, 9205c3f9a67SHugh Dickins enum migrate_mode mode) 921b20a3503SChristoph Lameter { 922bda807d4SMinchan Kim int rc = -EAGAIN; 923e7e3ffebSMatthew Wilcox (Oracle) bool is_lru = !__PageMovable(&src->page); 924b20a3503SChristoph Lameter 925e7e3ffebSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_locked(src), src); 926e7e3ffebSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_locked(dst), dst); 927b20a3503SChristoph Lameter 928bda807d4SMinchan Kim if (likely(is_lru)) { 92968f2736aSMatthew Wilcox (Oracle) struct address_space *mapping = folio_mapping(src); 93068f2736aSMatthew Wilcox (Oracle) 931b20a3503SChristoph Lameter if (!mapping) 93254184650SMatthew Wilcox (Oracle) rc = migrate_folio(mapping, dst, src, mode); 9335490da4fSMatthew Wilcox (Oracle) else if (mapping->a_ops->migrate_folio) 934b20a3503SChristoph Lameter /* 9355490da4fSMatthew Wilcox (Oracle) * Most folios have a mapping and most filesystems 9365490da4fSMatthew Wilcox (Oracle) * provide a migrate_folio callback. Anonymous folios 937bda807d4SMinchan Kim * are part of swap space which also has its own 9385490da4fSMatthew Wilcox (Oracle) * migrate_folio callback. This is the most common path 939bda807d4SMinchan Kim * for page migration. 940b20a3503SChristoph Lameter */ 9415490da4fSMatthew Wilcox (Oracle) rc = mapping->a_ops->migrate_folio(mapping, dst, src, 9425490da4fSMatthew Wilcox (Oracle) mode); 9438351a6e4SChristoph Lameter else 9448faa8ef5SMatthew Wilcox (Oracle) rc = fallback_migrate_folio(mapping, dst, src, mode); 945bda807d4SMinchan Kim } else { 94668f2736aSMatthew Wilcox (Oracle) const struct movable_operations *mops; 94768f2736aSMatthew Wilcox (Oracle) 948bda807d4SMinchan Kim /* 949bda807d4SMinchan Kim * In case of non-lru page, it could be released after 950bda807d4SMinchan Kim * isolation step. In that case, we shouldn't try migration. 951bda807d4SMinchan Kim */ 952e7e3ffebSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_isolated(src), src); 953e7e3ffebSMatthew Wilcox (Oracle) if (!folio_test_movable(src)) { 954bda807d4SMinchan Kim rc = MIGRATEPAGE_SUCCESS; 955e7e3ffebSMatthew Wilcox (Oracle) folio_clear_isolated(src); 956bda807d4SMinchan Kim goto out; 957bda807d4SMinchan Kim } 958bda807d4SMinchan Kim 95968f2736aSMatthew Wilcox (Oracle) mops = page_movable_ops(&src->page); 96068f2736aSMatthew Wilcox (Oracle) rc = mops->migrate_page(&dst->page, &src->page, mode); 961bda807d4SMinchan Kim WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS && 962e7e3ffebSMatthew Wilcox (Oracle) !folio_test_isolated(src)); 963bda807d4SMinchan Kim } 964b20a3503SChristoph Lameter 9655c3f9a67SHugh Dickins /* 966e7e3ffebSMatthew Wilcox (Oracle) * When successful, old pagecache src->mapping must be cleared before 967e7e3ffebSMatthew Wilcox (Oracle) * src is freed; but stats require that PageAnon be left as PageAnon. 9685c3f9a67SHugh Dickins */ 9695c3f9a67SHugh Dickins if (rc == MIGRATEPAGE_SUCCESS) { 970e7e3ffebSMatthew Wilcox (Oracle) if (__PageMovable(&src->page)) { 971e7e3ffebSMatthew Wilcox (Oracle) VM_BUG_ON_FOLIO(!folio_test_isolated(src), src); 972bda807d4SMinchan Kim 973bda807d4SMinchan Kim /* 974bda807d4SMinchan Kim * We clear PG_movable under page_lock so any compactor 975bda807d4SMinchan Kim * cannot try to migrate this page. 976bda807d4SMinchan Kim */ 977e7e3ffebSMatthew Wilcox (Oracle) folio_clear_isolated(src); 978bda807d4SMinchan Kim } 979bda807d4SMinchan Kim 980bda807d4SMinchan Kim /* 981e7e3ffebSMatthew Wilcox (Oracle) * Anonymous and movable src->mapping will be cleared by 982bda807d4SMinchan Kim * free_pages_prepare so don't reset it here for keeping 983bda807d4SMinchan Kim * the type to work PageAnon, for example. 984bda807d4SMinchan Kim */ 985e7e3ffebSMatthew Wilcox (Oracle) if (!folio_mapping_flags(src)) 986e7e3ffebSMatthew Wilcox (Oracle) src->mapping = NULL; 987d2b2c6ddSLars Persson 988e7e3ffebSMatthew Wilcox (Oracle) if (likely(!folio_is_zone_device(dst))) 989e7e3ffebSMatthew Wilcox (Oracle) flush_dcache_folio(dst); 9903fe2011fSMel Gorman } 991bda807d4SMinchan Kim out: 992e24f0b8fSChristoph Lameter return rc; 993e24f0b8fSChristoph Lameter } 994e24f0b8fSChristoph Lameter 9950dabec93SMinchan Kim static int __unmap_and_move(struct page *page, struct page *newpage, 9969c620e2bSHugh Dickins int force, enum migrate_mode mode) 997e24f0b8fSChristoph Lameter { 9984b8554c5SMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 9994eecb8b9SMatthew Wilcox (Oracle) struct folio *dst = page_folio(newpage); 10000dabec93SMinchan Kim int rc = -EAGAIN; 1001213ecb31SBaolin Wang bool page_was_mapped = false; 10023f6c8272SMel Gorman struct anon_vma *anon_vma = NULL; 1003bda807d4SMinchan Kim bool is_lru = !__PageMovable(page); 100495a402c3SChristoph Lameter 1005529ae9aaSNick Piggin if (!trylock_page(page)) { 1006a6bc32b8SMel Gorman if (!force || mode == MIGRATE_ASYNC) 10070dabec93SMinchan Kim goto out; 10083e7d3449SMel Gorman 10093e7d3449SMel Gorman /* 10103e7d3449SMel Gorman * It's not safe for direct compaction to call lock_page. 10113e7d3449SMel Gorman * For example, during page readahead pages are added locked 10123e7d3449SMel Gorman * to the LRU. Later, when the IO completes the pages are 10133e7d3449SMel Gorman * marked uptodate and unlocked. However, the queueing 10143e7d3449SMel Gorman * could be merging multiple pages for one bio (e.g. 1015d4388340SMatthew Wilcox (Oracle) * mpage_readahead). If an allocation happens for the 10163e7d3449SMel Gorman * second or third page, the process can end up locking 10173e7d3449SMel Gorman * the same page twice and deadlocking. Rather than 10183e7d3449SMel Gorman * trying to be clever about what pages can be locked, 10193e7d3449SMel Gorman * avoid the use of lock_page for direct compaction 10203e7d3449SMel Gorman * altogether. 10213e7d3449SMel Gorman */ 10223e7d3449SMel Gorman if (current->flags & PF_MEMALLOC) 10230dabec93SMinchan Kim goto out; 10243e7d3449SMel Gorman 1025e24f0b8fSChristoph Lameter lock_page(page); 1026e24f0b8fSChristoph Lameter } 1027e24f0b8fSChristoph Lameter 1028e24f0b8fSChristoph Lameter if (PageWriteback(page)) { 102911bc82d6SAndrea Arcangeli /* 1030fed5b64aSJianguo Wu * Only in the case of a full synchronous migration is it 1031a6bc32b8SMel Gorman * necessary to wait for PageWriteback. In the async case, 1032a6bc32b8SMel Gorman * the retry loop is too short and in the sync-light case, 1033a6bc32b8SMel Gorman * the overhead of stalling is too much 103411bc82d6SAndrea Arcangeli */ 10352916ecc0SJérôme Glisse switch (mode) { 10362916ecc0SJérôme Glisse case MIGRATE_SYNC: 10372916ecc0SJérôme Glisse case MIGRATE_SYNC_NO_COPY: 10382916ecc0SJérôme Glisse break; 10392916ecc0SJérôme Glisse default: 104011bc82d6SAndrea Arcangeli rc = -EBUSY; 10410a31bc97SJohannes Weiner goto out_unlock; 104211bc82d6SAndrea Arcangeli } 104311bc82d6SAndrea Arcangeli if (!force) 10440a31bc97SJohannes Weiner goto out_unlock; 1045e24f0b8fSChristoph Lameter wait_on_page_writeback(page); 1046e24f0b8fSChristoph Lameter } 104703f15c86SHugh Dickins 1048e24f0b8fSChristoph Lameter /* 104968a9843fSBaolin Wang * By try_to_migrate(), page->mapcount goes down to 0 here. In this case, 1050dc386d4dSKAMEZAWA Hiroyuki * we cannot notice that anon_vma is freed while we migrates a page. 10511ce82b69SHugh Dickins * This get_anon_vma() delays freeing anon_vma pointer until the end 1052dc386d4dSKAMEZAWA Hiroyuki * of migration. File cache pages are no problem because of page_lock() 1053989f89c5SKAMEZAWA Hiroyuki * File Caches may use write_page() or lock_page() in migration, then, 1054989f89c5SKAMEZAWA Hiroyuki * just care Anon page here. 10553fe2011fSMel Gorman * 105603f15c86SHugh Dickins * Only page_get_anon_vma() understands the subtleties of 105703f15c86SHugh Dickins * getting a hold on an anon_vma from outside one of its mms. 105803f15c86SHugh Dickins * But if we cannot get anon_vma, then we won't need it anyway, 105903f15c86SHugh Dickins * because that implies that the anon page is no longer mapped 106003f15c86SHugh Dickins * (and cannot be remapped so long as we hold the page lock). 10613fe2011fSMel Gorman */ 106203f15c86SHugh Dickins if (PageAnon(page) && !PageKsm(page)) 106303f15c86SHugh Dickins anon_vma = page_get_anon_vma(page); 106462e1c553SShaohua Li 10657db7671fSHugh Dickins /* 10667db7671fSHugh Dickins * Block others from accessing the new page when we get around to 10677db7671fSHugh Dickins * establishing additional references. We are usually the only one 10687db7671fSHugh Dickins * holding a reference to newpage at this point. We used to have a BUG 10697db7671fSHugh Dickins * here if trylock_page(newpage) fails, but would like to allow for 10707db7671fSHugh Dickins * cases where there might be a race with the previous use of newpage. 10717db7671fSHugh Dickins * This is much like races on refcount of oldpage: just don't BUG(). 10727db7671fSHugh Dickins */ 10737db7671fSHugh Dickins if (unlikely(!trylock_page(newpage))) 10747db7671fSHugh Dickins goto out_unlock; 10757db7671fSHugh Dickins 1076bda807d4SMinchan Kim if (unlikely(!is_lru)) { 1077e7e3ffebSMatthew Wilcox (Oracle) rc = move_to_new_folio(dst, folio, mode); 1078bda807d4SMinchan Kim goto out_unlock_both; 1079bda807d4SMinchan Kim } 1080bda807d4SMinchan Kim 1081dc386d4dSKAMEZAWA Hiroyuki /* 108262e1c553SShaohua Li * Corner case handling: 108362e1c553SShaohua Li * 1. When a new swap-cache page is read into, it is added to the LRU 108462e1c553SShaohua Li * and treated as swapcache but it has no rmap yet. 108562e1c553SShaohua Li * Calling try_to_unmap() against a page->mapping==NULL page will 108662e1c553SShaohua Li * trigger a BUG. So handle it here. 1087d12b8951SYang Shi * 2. An orphaned page (see truncate_cleanup_page) might have 108862e1c553SShaohua Li * fs-private metadata. The page can be picked up due to memory 108962e1c553SShaohua Li * offlining. Everywhere else except page reclaim, the page is 109062e1c553SShaohua Li * invisible to the vm, so the page can not be migrated. So try to 109162e1c553SShaohua Li * free the metadata, so the page can be freed. 1092dc386d4dSKAMEZAWA Hiroyuki */ 109362e1c553SShaohua Li if (!page->mapping) { 1094309381feSSasha Levin VM_BUG_ON_PAGE(PageAnon(page), page); 10951ce82b69SHugh Dickins if (page_has_private(page)) { 109668189fefSMatthew Wilcox (Oracle) try_to_free_buffers(folio); 10977db7671fSHugh Dickins goto out_unlock_both; 109862e1c553SShaohua Li } 10997db7671fSHugh Dickins } else if (page_mapped(page)) { 11007db7671fSHugh Dickins /* Establish migration ptes */ 110103f15c86SHugh Dickins VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma, 110203f15c86SHugh Dickins page); 11034b8554c5SMatthew Wilcox (Oracle) try_to_migrate(folio, 0); 1104213ecb31SBaolin Wang page_was_mapped = true; 11052ebba6b7SHugh Dickins } 1106dc386d4dSKAMEZAWA Hiroyuki 1107e24f0b8fSChristoph Lameter if (!page_mapped(page)) 1108e7e3ffebSMatthew Wilcox (Oracle) rc = move_to_new_folio(dst, folio, mode); 1109e24f0b8fSChristoph Lameter 1110c3096e67SHugh Dickins /* 1111c3096e67SHugh Dickins * When successful, push newpage to LRU immediately: so that if it 1112c3096e67SHugh Dickins * turns out to be an mlocked page, remove_migration_ptes() will 1113c3096e67SHugh Dickins * automatically build up the correct newpage->mlock_count for it. 1114c3096e67SHugh Dickins * 1115c3096e67SHugh Dickins * We would like to do something similar for the old page, when 1116c3096e67SHugh Dickins * unsuccessful, and other cases when a page has been temporarily 1117c3096e67SHugh Dickins * isolated from the unevictable LRU: but this case is the easiest. 1118c3096e67SHugh Dickins */ 1119c3096e67SHugh Dickins if (rc == MIGRATEPAGE_SUCCESS) { 1120c3096e67SHugh Dickins lru_cache_add(newpage); 11215c3f9a67SHugh Dickins if (page_was_mapped) 1122c3096e67SHugh Dickins lru_add_drain(); 1123c3096e67SHugh Dickins } 1124c3096e67SHugh Dickins 11255c3f9a67SHugh Dickins if (page_was_mapped) 11264eecb8b9SMatthew Wilcox (Oracle) remove_migration_ptes(folio, 11274eecb8b9SMatthew Wilcox (Oracle) rc == MIGRATEPAGE_SUCCESS ? dst : folio, false); 11283f6c8272SMel Gorman 11297db7671fSHugh Dickins out_unlock_both: 11307db7671fSHugh Dickins unlock_page(newpage); 11317db7671fSHugh Dickins out_unlock: 11323f6c8272SMel Gorman /* Drop an anon_vma reference if we took one */ 113376545066SRik van Riel if (anon_vma) 11349e60109fSPeter Zijlstra put_anon_vma(anon_vma); 1135b20a3503SChristoph Lameter unlock_page(page); 11360dabec93SMinchan Kim out: 1137c6c919ebSMinchan Kim /* 1138c3096e67SHugh Dickins * If migration is successful, decrease refcount of the newpage, 1139c6c919ebSMinchan Kim * which will not free the page because new page owner increased 1140c3096e67SHugh Dickins * refcounter. 1141c6c919ebSMinchan Kim */ 1142c3096e67SHugh Dickins if (rc == MIGRATEPAGE_SUCCESS) 1143c6c919ebSMinchan Kim put_page(newpage); 1144c6c919ebSMinchan Kim 11450dabec93SMinchan Kim return rc; 11460dabec93SMinchan Kim } 114795a402c3SChristoph Lameter 11480dabec93SMinchan Kim /* 11490dabec93SMinchan Kim * Obtain the lock on page, remove all ptes and migrate the page 11500dabec93SMinchan Kim * to the newly allocated page in newpage. 11510dabec93SMinchan Kim */ 11526ec4476aSLinus Torvalds static int unmap_and_move(new_page_t get_new_page, 1153ef2a5153SGeert Uytterhoeven free_page_t put_new_page, 1154ef2a5153SGeert Uytterhoeven unsigned long private, struct page *page, 1155add05cecSNaoya Horiguchi int force, enum migrate_mode mode, 1156dd4ae78aSYang Shi enum migrate_reason reason, 1157dd4ae78aSYang Shi struct list_head *ret) 11580dabec93SMinchan Kim { 11592def7424SHugh Dickins int rc = MIGRATEPAGE_SUCCESS; 116074d4a579SYang Shi struct page *newpage = NULL; 11610dabec93SMinchan Kim 116294723aafSMichal Hocko if (!thp_migration_supported() && PageTransHuge(page)) 1163d532e2e5SYang Shi return -ENOSYS; 116494723aafSMichal Hocko 11650dabec93SMinchan Kim if (page_count(page) == 1) { 1166160088b3SMiaohe Lin /* Page was freed from under us. So we are done. */ 1167c6c919ebSMinchan Kim ClearPageActive(page); 1168c6c919ebSMinchan Kim ClearPageUnevictable(page); 1169160088b3SMiaohe Lin /* free_pages_prepare() will clear PG_isolated. */ 11700dabec93SMinchan Kim goto out; 11710dabec93SMinchan Kim } 11720dabec93SMinchan Kim 117374d4a579SYang Shi newpage = get_new_page(page, private); 117474d4a579SYang Shi if (!newpage) 117574d4a579SYang Shi return -ENOMEM; 117674d4a579SYang Shi 1177b653db77SMatthew Wilcox (Oracle) newpage->private = 0; 11789c620e2bSHugh Dickins rc = __unmap_and_move(page, newpage, force, mode); 1179c6c919ebSMinchan Kim if (rc == MIGRATEPAGE_SUCCESS) 11807cd12b4aSVlastimil Babka set_page_owner_migrate_reason(newpage, reason); 1181bf6bddf1SRafael Aquini 11820dabec93SMinchan Kim out: 1183e24f0b8fSChristoph Lameter if (rc != -EAGAIN) { 1184aaa994b3SChristoph Lameter /* 1185aaa994b3SChristoph Lameter * A page that has been migrated has all references 1186aaa994b3SChristoph Lameter * removed and will be freed. A page that has not been 1187c23a0c99SRalph Campbell * migrated will have kept its references and be restored. 1188aaa994b3SChristoph Lameter */ 1189aaa994b3SChristoph Lameter list_del(&page->lru); 1190e24f0b8fSChristoph Lameter } 119168711a74SDavid Rientjes 119295a402c3SChristoph Lameter /* 1193c6c919ebSMinchan Kim * If migration is successful, releases reference grabbed during 1194c6c919ebSMinchan Kim * isolation. Otherwise, restore the page to right list unless 1195c6c919ebSMinchan Kim * we want to retry. 119695a402c3SChristoph Lameter */ 1197c6c919ebSMinchan Kim if (rc == MIGRATEPAGE_SUCCESS) { 1198dd4ae78aSYang Shi /* 1199dd4ae78aSYang Shi * Compaction can migrate also non-LRU pages which are 1200dd4ae78aSYang Shi * not accounted to NR_ISOLATED_*. They can be recognized 1201dd4ae78aSYang Shi * as __PageMovable 1202dd4ae78aSYang Shi */ 1203dd4ae78aSYang Shi if (likely(!__PageMovable(page))) 1204dd4ae78aSYang Shi mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + 1205dd4ae78aSYang Shi page_is_file_lru(page), -thp_nr_pages(page)); 1206dd4ae78aSYang Shi 120779f5f8faSOscar Salvador if (reason != MR_MEMORY_FAILURE) 1208c6c919ebSMinchan Kim /* 120979f5f8faSOscar Salvador * We release the page in page_handle_poison. 1210c6c919ebSMinchan Kim */ 121179f5f8faSOscar Salvador put_page(page); 1212c6c919ebSMinchan Kim } else { 1213dd4ae78aSYang Shi if (rc != -EAGAIN) 1214dd4ae78aSYang Shi list_add_tail(&page->lru, ret); 1215bda807d4SMinchan Kim 1216cf4b769aSHugh Dickins if (put_new_page) 121768711a74SDavid Rientjes put_new_page(newpage, private); 1218c6c919ebSMinchan Kim else 1219d6d86c0aSKonstantin Khlebnikov put_page(newpage); 1220c6c919ebSMinchan Kim } 122168711a74SDavid Rientjes 1222e24f0b8fSChristoph Lameter return rc; 1223e24f0b8fSChristoph Lameter } 1224b20a3503SChristoph Lameter 1225e24f0b8fSChristoph Lameter /* 1226290408d4SNaoya Horiguchi * Counterpart of unmap_and_move_page() for hugepage migration. 1227290408d4SNaoya Horiguchi * 1228290408d4SNaoya Horiguchi * This function doesn't wait the completion of hugepage I/O 1229290408d4SNaoya Horiguchi * because there is no race between I/O and migration for hugepage. 1230290408d4SNaoya Horiguchi * Note that currently hugepage I/O occurs only in direct I/O 1231290408d4SNaoya Horiguchi * where no lock is held and PG_writeback is irrelevant, 1232290408d4SNaoya Horiguchi * and writeback status of all subpages are counted in the reference 1233290408d4SNaoya Horiguchi * count of the head page (i.e. if all subpages of a 2MB hugepage are 1234290408d4SNaoya Horiguchi * under direct I/O, the reference of the head page is 512 and a bit more.) 1235290408d4SNaoya Horiguchi * This means that when we try to migrate hugepage whose subpages are 1236290408d4SNaoya Horiguchi * doing direct I/O, some references remain after try_to_unmap() and 1237290408d4SNaoya Horiguchi * hugepage migration fails without data corruption. 1238290408d4SNaoya Horiguchi * 1239290408d4SNaoya Horiguchi * There is also no race when direct I/O is issued on the page under migration, 1240290408d4SNaoya Horiguchi * because then pte is replaced with migration swap entry and direct I/O code 1241290408d4SNaoya Horiguchi * will wait in the page fault for migration to complete. 1242290408d4SNaoya Horiguchi */ 1243290408d4SNaoya Horiguchi static int unmap_and_move_huge_page(new_page_t get_new_page, 124468711a74SDavid Rientjes free_page_t put_new_page, unsigned long private, 124568711a74SDavid Rientjes struct page *hpage, int force, 1246dd4ae78aSYang Shi enum migrate_mode mode, int reason, 1247dd4ae78aSYang Shi struct list_head *ret) 1248290408d4SNaoya Horiguchi { 12494eecb8b9SMatthew Wilcox (Oracle) struct folio *dst, *src = page_folio(hpage); 12502def7424SHugh Dickins int rc = -EAGAIN; 12512ebba6b7SHugh Dickins int page_was_mapped = 0; 125232665f2bSJoonsoo Kim struct page *new_hpage; 1253290408d4SNaoya Horiguchi struct anon_vma *anon_vma = NULL; 1254c0d0381aSMike Kravetz struct address_space *mapping = NULL; 1255290408d4SNaoya Horiguchi 125683467efbSNaoya Horiguchi /* 12577ed2c31dSAnshuman Khandual * Migratability of hugepages depends on architectures and their size. 125883467efbSNaoya Horiguchi * This check is necessary because some callers of hugepage migration 125983467efbSNaoya Horiguchi * like soft offline and memory hotremove don't walk through page 126083467efbSNaoya Horiguchi * tables or check whether the hugepage is pmd-based or not before 126183467efbSNaoya Horiguchi * kicking migration. 126283467efbSNaoya Horiguchi */ 1263100873d7SNaoya Horiguchi if (!hugepage_migration_supported(page_hstate(hpage))) { 1264dd4ae78aSYang Shi list_move_tail(&hpage->lru, ret); 126583467efbSNaoya Horiguchi return -ENOSYS; 126632665f2bSJoonsoo Kim } 126783467efbSNaoya Horiguchi 126871a64f61SMuchun Song if (page_count(hpage) == 1) { 126971a64f61SMuchun Song /* page was freed from under us. So we are done. */ 127071a64f61SMuchun Song putback_active_hugepage(hpage); 127171a64f61SMuchun Song return MIGRATEPAGE_SUCCESS; 127271a64f61SMuchun Song } 127371a64f61SMuchun Song 1274666feb21SMichal Hocko new_hpage = get_new_page(hpage, private); 1275290408d4SNaoya Horiguchi if (!new_hpage) 1276290408d4SNaoya Horiguchi return -ENOMEM; 12774eecb8b9SMatthew Wilcox (Oracle) dst = page_folio(new_hpage); 1278290408d4SNaoya Horiguchi 1279290408d4SNaoya Horiguchi if (!trylock_page(hpage)) { 12802916ecc0SJérôme Glisse if (!force) 1281290408d4SNaoya Horiguchi goto out; 12822916ecc0SJérôme Glisse switch (mode) { 12832916ecc0SJérôme Glisse case MIGRATE_SYNC: 12842916ecc0SJérôme Glisse case MIGRATE_SYNC_NO_COPY: 12852916ecc0SJérôme Glisse break; 12862916ecc0SJérôme Glisse default: 12872916ecc0SJérôme Glisse goto out; 12882916ecc0SJérôme Glisse } 1289290408d4SNaoya Horiguchi lock_page(hpage); 1290290408d4SNaoya Horiguchi } 1291290408d4SNaoya Horiguchi 1292cb6acd01SMike Kravetz /* 1293cb6acd01SMike Kravetz * Check for pages which are in the process of being freed. Without 1294cb6acd01SMike Kravetz * page_mapping() set, hugetlbfs specific move page routine will not 1295cb6acd01SMike Kravetz * be called and we could leak usage counts for subpools. 1296cb6acd01SMike Kravetz */ 12976acfb5baSMuchun Song if (hugetlb_page_subpool(hpage) && !page_mapping(hpage)) { 1298cb6acd01SMike Kravetz rc = -EBUSY; 1299cb6acd01SMike Kravetz goto out_unlock; 1300cb6acd01SMike Kravetz } 1301cb6acd01SMike Kravetz 1302746b18d4SPeter Zijlstra if (PageAnon(hpage)) 1303746b18d4SPeter Zijlstra anon_vma = page_get_anon_vma(hpage); 1304290408d4SNaoya Horiguchi 13057db7671fSHugh Dickins if (unlikely(!trylock_page(new_hpage))) 13067db7671fSHugh Dickins goto put_anon; 13077db7671fSHugh Dickins 13082ebba6b7SHugh Dickins if (page_mapped(hpage)) { 1309a98a2f0cSAlistair Popple enum ttu_flags ttu = 0; 1310336bf30eSMike Kravetz 1311336bf30eSMike Kravetz if (!PageAnon(hpage)) { 1312c0d0381aSMike Kravetz /* 1313336bf30eSMike Kravetz * In shared mappings, try_to_unmap could potentially 1314336bf30eSMike Kravetz * call huge_pmd_unshare. Because of this, take 1315336bf30eSMike Kravetz * semaphore in write mode here and set TTU_RMAP_LOCKED 1316336bf30eSMike Kravetz * to let lower levels know we have taken the lock. 1317c0d0381aSMike Kravetz */ 1318c0d0381aSMike Kravetz mapping = hugetlb_page_mapping_lock_write(hpage); 1319c0d0381aSMike Kravetz if (unlikely(!mapping)) 1320c0d0381aSMike Kravetz goto unlock_put_anon; 1321c0d0381aSMike Kravetz 13225202978bSMiaohe Lin ttu = TTU_RMAP_LOCKED; 1323336bf30eSMike Kravetz } 1324336bf30eSMike Kravetz 13254b8554c5SMatthew Wilcox (Oracle) try_to_migrate(src, ttu); 13262ebba6b7SHugh Dickins page_was_mapped = 1; 1327336bf30eSMike Kravetz 13285202978bSMiaohe Lin if (ttu & TTU_RMAP_LOCKED) 1329336bf30eSMike Kravetz i_mmap_unlock_write(mapping); 13302ebba6b7SHugh Dickins } 1331290408d4SNaoya Horiguchi 1332290408d4SNaoya Horiguchi if (!page_mapped(hpage)) 1333e7e3ffebSMatthew Wilcox (Oracle) rc = move_to_new_folio(dst, src, mode); 1334290408d4SNaoya Horiguchi 1335336bf30eSMike Kravetz if (page_was_mapped) 13364eecb8b9SMatthew Wilcox (Oracle) remove_migration_ptes(src, 13374eecb8b9SMatthew Wilcox (Oracle) rc == MIGRATEPAGE_SUCCESS ? dst : src, false); 1338290408d4SNaoya Horiguchi 1339c0d0381aSMike Kravetz unlock_put_anon: 13407db7671fSHugh Dickins unlock_page(new_hpage); 13417db7671fSHugh Dickins 13427db7671fSHugh Dickins put_anon: 1343fd4a4663SHugh Dickins if (anon_vma) 13449e60109fSPeter Zijlstra put_anon_vma(anon_vma); 13458e6ac7faSAneesh Kumar K.V 13462def7424SHugh Dickins if (rc == MIGRATEPAGE_SUCCESS) { 1347ab5ac90aSMichal Hocko move_hugetlb_state(hpage, new_hpage, reason); 13482def7424SHugh Dickins put_new_page = NULL; 13492def7424SHugh Dickins } 13508e6ac7faSAneesh Kumar K.V 1351cb6acd01SMike Kravetz out_unlock: 1352290408d4SNaoya Horiguchi unlock_page(hpage); 135309761333SHillf Danton out: 1354dd4ae78aSYang Shi if (rc == MIGRATEPAGE_SUCCESS) 1355b8ec1ceeSNaoya Horiguchi putback_active_hugepage(hpage); 1356a04840c6SMiaohe Lin else if (rc != -EAGAIN) 1357dd4ae78aSYang Shi list_move_tail(&hpage->lru, ret); 135868711a74SDavid Rientjes 135968711a74SDavid Rientjes /* 136068711a74SDavid Rientjes * If migration was not successful and there's a freeing callback, use 136168711a74SDavid Rientjes * it. Otherwise, put_page() will drop the reference grabbed during 136268711a74SDavid Rientjes * isolation. 136368711a74SDavid Rientjes */ 13642def7424SHugh Dickins if (put_new_page) 136568711a74SDavid Rientjes put_new_page(new_hpage, private); 136668711a74SDavid Rientjes else 13673aaa76e1SNaoya Horiguchi putback_active_hugepage(new_hpage); 136868711a74SDavid Rientjes 1369290408d4SNaoya Horiguchi return rc; 1370290408d4SNaoya Horiguchi } 1371290408d4SNaoya Horiguchi 1372d532e2e5SYang Shi static inline int try_split_thp(struct page *page, struct page **page2, 1373d532e2e5SYang Shi struct list_head *from) 1374d532e2e5SYang Shi { 1375d532e2e5SYang Shi int rc = 0; 1376d532e2e5SYang Shi 1377d532e2e5SYang Shi lock_page(page); 1378d532e2e5SYang Shi rc = split_huge_page_to_list(page, from); 1379d532e2e5SYang Shi unlock_page(page); 1380d532e2e5SYang Shi if (!rc) 1381d532e2e5SYang Shi list_safe_reset_next(page, *page2, lru); 1382d532e2e5SYang Shi 1383d532e2e5SYang Shi return rc; 1384d532e2e5SYang Shi } 1385d532e2e5SYang Shi 1386290408d4SNaoya Horiguchi /* 1387c73e5c9cSSrivatsa S. Bhat * migrate_pages - migrate the pages specified in a list, to the free pages 1388c73e5c9cSSrivatsa S. Bhat * supplied as the target for the page migration 1389e24f0b8fSChristoph Lameter * 1390c73e5c9cSSrivatsa S. Bhat * @from: The list of pages to be migrated. 1391c73e5c9cSSrivatsa S. Bhat * @get_new_page: The function used to allocate free pages to be used 1392c73e5c9cSSrivatsa S. Bhat * as the target of the page migration. 139368711a74SDavid Rientjes * @put_new_page: The function used to free target pages if migration 139468711a74SDavid Rientjes * fails, or NULL if no special handling is necessary. 1395c73e5c9cSSrivatsa S. Bhat * @private: Private data to be passed on to get_new_page() 1396c73e5c9cSSrivatsa S. Bhat * @mode: The migration mode that specifies the constraints for 1397c73e5c9cSSrivatsa S. Bhat * page migration, if any. 1398c73e5c9cSSrivatsa S. Bhat * @reason: The reason for page migration. 1399b5bade97SBaolin Wang * @ret_succeeded: Set to the number of normal pages migrated successfully if 14005ac95884SYang Shi * the caller passes a non-NULL pointer. 1401e24f0b8fSChristoph Lameter * 1402c73e5c9cSSrivatsa S. Bhat * The function returns after 10 attempts or if no pages are movable any more 1403c73e5c9cSSrivatsa S. Bhat * because the list has become empty or no retryable pages exist any more. 1404dd4ae78aSYang Shi * It is caller's responsibility to call putback_movable_pages() to return pages 1405dd4ae78aSYang Shi * to the LRU or free list only if ret != 0. 1406e24f0b8fSChristoph Lameter * 14075d39a7ebSBaolin Wang * Returns the number of {normal page, THP, hugetlb} that were not migrated, or 14085d39a7ebSBaolin Wang * an error code. The number of THP splits will be considered as the number of 14095d39a7ebSBaolin Wang * non-migrated THP, no matter how many subpages of the THP are migrated successfully. 1410e24f0b8fSChristoph Lameter */ 14119c620e2bSHugh Dickins int migrate_pages(struct list_head *from, new_page_t get_new_page, 141268711a74SDavid Rientjes free_page_t put_new_page, unsigned long private, 14135ac95884SYang Shi enum migrate_mode mode, int reason, unsigned int *ret_succeeded) 1414e24f0b8fSChristoph Lameter { 1415e24f0b8fSChristoph Lameter int retry = 1; 14161a5bae25SAnshuman Khandual int thp_retry = 1; 1417e24f0b8fSChristoph Lameter int nr_failed = 0; 1418b5bade97SBaolin Wang int nr_failed_pages = 0; 14195647bc29SMel Gorman int nr_succeeded = 0; 14201a5bae25SAnshuman Khandual int nr_thp_succeeded = 0; 14211a5bae25SAnshuman Khandual int nr_thp_failed = 0; 14221a5bae25SAnshuman Khandual int nr_thp_split = 0; 1423e24f0b8fSChristoph Lameter int pass = 0; 14241a5bae25SAnshuman Khandual bool is_thp = false; 1425e24f0b8fSChristoph Lameter struct page *page; 1426e24f0b8fSChristoph Lameter struct page *page2; 14271a5bae25SAnshuman Khandual int rc, nr_subpages; 1428dd4ae78aSYang Shi LIST_HEAD(ret_pages); 1429b5bade97SBaolin Wang LIST_HEAD(thp_split_pages); 1430b0b515bfSYang Shi bool nosplit = (reason == MR_NUMA_MISPLACED); 1431b5bade97SBaolin Wang bool no_subpage_counting = false; 14322d1db3b1SChristoph Lameter 14337bc1aec5SLiam Mark trace_mm_migrate_pages_start(mode, reason); 14347bc1aec5SLiam Mark 1435b5bade97SBaolin Wang thp_subpage_migration: 14361a5bae25SAnshuman Khandual for (pass = 0; pass < 10 && (retry || thp_retry); pass++) { 1437e24f0b8fSChristoph Lameter retry = 0; 14381a5bae25SAnshuman Khandual thp_retry = 0; 1439e24f0b8fSChristoph Lameter 1440e24f0b8fSChristoph Lameter list_for_each_entry_safe(page, page2, from, lru) { 144194723aafSMichal Hocko retry: 14421a5bae25SAnshuman Khandual /* 14431a5bae25SAnshuman Khandual * THP statistics is based on the source huge page. 14441a5bae25SAnshuman Khandual * Capture required information that might get lost 14451a5bae25SAnshuman Khandual * during migration. 14461a5bae25SAnshuman Khandual */ 14476c5c7b9fSZi Yan is_thp = PageTransHuge(page) && !PageHuge(page); 14485d39a7ebSBaolin Wang nr_subpages = compound_nr(page); 1449e24f0b8fSChristoph Lameter cond_resched(); 1450e24f0b8fSChristoph Lameter 145131caf665SNaoya Horiguchi if (PageHuge(page)) 145231caf665SNaoya Horiguchi rc = unmap_and_move_huge_page(get_new_page, 145368711a74SDavid Rientjes put_new_page, private, page, 1454dd4ae78aSYang Shi pass > 2, mode, reason, 1455dd4ae78aSYang Shi &ret_pages); 145631caf665SNaoya Horiguchi else 145768711a74SDavid Rientjes rc = unmap_and_move(get_new_page, put_new_page, 1458add05cecSNaoya Horiguchi private, page, pass > 2, mode, 1459dd4ae78aSYang Shi reason, &ret_pages); 1460dd4ae78aSYang Shi /* 1461dd4ae78aSYang Shi * The rules are: 1462dd4ae78aSYang Shi * Success: non hugetlb page will be freed, hugetlb 1463dd4ae78aSYang Shi * page will be put back 1464dd4ae78aSYang Shi * -EAGAIN: stay on the from list 1465dd4ae78aSYang Shi * -ENOMEM: stay on the from list 1466dd4ae78aSYang Shi * Other errno: put on ret_pages list then splice to 1467dd4ae78aSYang Shi * from list 1468dd4ae78aSYang Shi */ 1469e24f0b8fSChristoph Lameter switch(rc) { 147094723aafSMichal Hocko /* 147194723aafSMichal Hocko * THP migration might be unsupported or the 147294723aafSMichal Hocko * allocation could've failed so we should 147394723aafSMichal Hocko * retry on the same page with the THP split 147494723aafSMichal Hocko * to base pages. 147594723aafSMichal Hocko * 147694723aafSMichal Hocko * Head page is retried immediately and tail 147794723aafSMichal Hocko * pages are added to the tail of the list so 147894723aafSMichal Hocko * we encounter them after the rest of the list 147994723aafSMichal Hocko * is processed. 148094723aafSMichal Hocko */ 1481d532e2e5SYang Shi case -ENOSYS: 1482d532e2e5SYang Shi /* THP migration is unsupported */ 14836c5c7b9fSZi Yan if (is_thp) { 1484b5bade97SBaolin Wang nr_thp_failed++; 1485b5bade97SBaolin Wang if (!try_split_thp(page, &page2, &thp_split_pages)) { 1486d532e2e5SYang Shi nr_thp_split++; 1487d532e2e5SYang Shi goto retry; 1488d532e2e5SYang Shi } 1489f430893bSMiaohe Lin /* Hugetlb migration is unsupported */ 1490f430893bSMiaohe Lin } else if (!no_subpage_counting) { 1491f430893bSMiaohe Lin nr_failed++; 1492d532e2e5SYang Shi } 1493d532e2e5SYang Shi 14945d39a7ebSBaolin Wang nr_failed_pages += nr_subpages; 1495d532e2e5SYang Shi break; 1496d532e2e5SYang Shi case -ENOMEM: 1497d532e2e5SYang Shi /* 1498d532e2e5SYang Shi * When memory is low, don't bother to try to migrate 1499d532e2e5SYang Shi * other pages, just exit. 1500b0b515bfSYang Shi * THP NUMA faulting doesn't split THP to retry. 1501d532e2e5SYang Shi */ 1502b0b515bfSYang Shi if (is_thp && !nosplit) { 1503b5bade97SBaolin Wang nr_thp_failed++; 1504b5bade97SBaolin Wang if (!try_split_thp(page, &page2, &thp_split_pages)) { 15051a5bae25SAnshuman Khandual nr_thp_split++; 150694723aafSMichal Hocko goto retry; 150794723aafSMichal Hocko } 1508f430893bSMiaohe Lin } else if (!no_subpage_counting) { 1509f430893bSMiaohe Lin nr_failed++; 15101a5bae25SAnshuman Khandual } 1511b5bade97SBaolin Wang 15125d39a7ebSBaolin Wang nr_failed_pages += nr_subpages; 151369a041ffSMiaohe Lin /* 151469a041ffSMiaohe Lin * There might be some subpages of fail-to-migrate THPs 151569a041ffSMiaohe Lin * left in thp_split_pages list. Move them back to migration 151669a041ffSMiaohe Lin * list so that they could be put back to the right list by 151769a041ffSMiaohe Lin * the caller otherwise the page refcnt will be leaked. 151869a041ffSMiaohe Lin */ 151969a041ffSMiaohe Lin list_splice_init(&thp_split_pages, from); 152069a041ffSMiaohe Lin nr_thp_failed += thp_retry; 152195a402c3SChristoph Lameter goto out; 1522e24f0b8fSChristoph Lameter case -EAGAIN: 1523f430893bSMiaohe Lin if (is_thp) 15241a5bae25SAnshuman Khandual thp_retry++; 1525f430893bSMiaohe Lin else 1526b20a3503SChristoph Lameter retry++; 1527e24f0b8fSChristoph Lameter break; 152878bd5209SRafael Aquini case MIGRATEPAGE_SUCCESS: 15295d39a7ebSBaolin Wang nr_succeeded += nr_subpages; 1530f430893bSMiaohe Lin if (is_thp) 15311a5bae25SAnshuman Khandual nr_thp_succeeded++; 15321a5bae25SAnshuman Khandual break; 1533e24f0b8fSChristoph Lameter default: 1534354a3363SNaoya Horiguchi /* 1535d532e2e5SYang Shi * Permanent failure (-EBUSY, etc.): 1536354a3363SNaoya Horiguchi * unlike -EAGAIN case, the failed page is 1537354a3363SNaoya Horiguchi * removed from migration page list and not 1538354a3363SNaoya Horiguchi * retried in the next outer loop. 1539354a3363SNaoya Horiguchi */ 1540f430893bSMiaohe Lin if (is_thp) 15411a5bae25SAnshuman Khandual nr_thp_failed++; 1542f430893bSMiaohe Lin else if (!no_subpage_counting) 1543b20a3503SChristoph Lameter nr_failed++; 1544f430893bSMiaohe Lin 15455d39a7ebSBaolin Wang nr_failed_pages += nr_subpages; 1546e24f0b8fSChristoph Lameter break; 1547b20a3503SChristoph Lameter } 1548b20a3503SChristoph Lameter } 1549e24f0b8fSChristoph Lameter } 1550b5bade97SBaolin Wang nr_failed += retry; 15511a5bae25SAnshuman Khandual nr_thp_failed += thp_retry; 1552b5bade97SBaolin Wang /* 1553b5bade97SBaolin Wang * Try to migrate subpages of fail-to-migrate THPs, no nr_failed 1554b5bade97SBaolin Wang * counting in this round, since all subpages of a THP is counted 1555b5bade97SBaolin Wang * as 1 failure in the first round. 1556b5bade97SBaolin Wang */ 1557b5bade97SBaolin Wang if (!list_empty(&thp_split_pages)) { 1558b5bade97SBaolin Wang /* 1559b5bade97SBaolin Wang * Move non-migrated pages (after 10 retries) to ret_pages 1560b5bade97SBaolin Wang * to avoid migrating them again. 1561b5bade97SBaolin Wang */ 1562b5bade97SBaolin Wang list_splice_init(from, &ret_pages); 1563b5bade97SBaolin Wang list_splice_init(&thp_split_pages, from); 1564b5bade97SBaolin Wang no_subpage_counting = true; 1565b5bade97SBaolin Wang retry = 1; 1566b5bade97SBaolin Wang goto thp_subpage_migration; 1567b5bade97SBaolin Wang } 1568b5bade97SBaolin Wang 1569b5bade97SBaolin Wang rc = nr_failed + nr_thp_failed; 157095a402c3SChristoph Lameter out: 1571dd4ae78aSYang Shi /* 1572dd4ae78aSYang Shi * Put the permanent failure page back to migration list, they 1573dd4ae78aSYang Shi * will be put back to the right list by the caller. 1574dd4ae78aSYang Shi */ 1575dd4ae78aSYang Shi list_splice(&ret_pages, from); 1576dd4ae78aSYang Shi 15775647bc29SMel Gorman count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded); 1578b5bade97SBaolin Wang count_vm_events(PGMIGRATE_FAIL, nr_failed_pages); 15791a5bae25SAnshuman Khandual count_vm_events(THP_MIGRATION_SUCCESS, nr_thp_succeeded); 15801a5bae25SAnshuman Khandual count_vm_events(THP_MIGRATION_FAIL, nr_thp_failed); 15811a5bae25SAnshuman Khandual count_vm_events(THP_MIGRATION_SPLIT, nr_thp_split); 1582b5bade97SBaolin Wang trace_mm_migrate_pages(nr_succeeded, nr_failed_pages, nr_thp_succeeded, 15831a5bae25SAnshuman Khandual nr_thp_failed, nr_thp_split, mode, reason); 15847b2a2d4aSMel Gorman 15855ac95884SYang Shi if (ret_succeeded) 15865ac95884SYang Shi *ret_succeeded = nr_succeeded; 15875ac95884SYang Shi 158895a402c3SChristoph Lameter return rc; 1589b20a3503SChristoph Lameter } 1590b20a3503SChristoph Lameter 159119fc7bedSJoonsoo Kim struct page *alloc_migration_target(struct page *page, unsigned long private) 1592b4b38223SJoonsoo Kim { 1593ffe06786SMatthew Wilcox (Oracle) struct folio *folio = page_folio(page); 159419fc7bedSJoonsoo Kim struct migration_target_control *mtc; 159519fc7bedSJoonsoo Kim gfp_t gfp_mask; 1596b4b38223SJoonsoo Kim unsigned int order = 0; 1597ffe06786SMatthew Wilcox (Oracle) struct folio *new_folio = NULL; 159819fc7bedSJoonsoo Kim int nid; 159919fc7bedSJoonsoo Kim int zidx; 160019fc7bedSJoonsoo Kim 160119fc7bedSJoonsoo Kim mtc = (struct migration_target_control *)private; 160219fc7bedSJoonsoo Kim gfp_mask = mtc->gfp_mask; 160319fc7bedSJoonsoo Kim nid = mtc->nid; 160419fc7bedSJoonsoo Kim if (nid == NUMA_NO_NODE) 1605ffe06786SMatthew Wilcox (Oracle) nid = folio_nid(folio); 1606b4b38223SJoonsoo Kim 1607ffe06786SMatthew Wilcox (Oracle) if (folio_test_hugetlb(folio)) { 1608ffe06786SMatthew Wilcox (Oracle) struct hstate *h = page_hstate(&folio->page); 1609d92bbc27SJoonsoo Kim 161019fc7bedSJoonsoo Kim gfp_mask = htlb_modify_alloc_mask(h, gfp_mask); 161119fc7bedSJoonsoo Kim return alloc_huge_page_nodemask(h, nid, mtc->nmask, gfp_mask); 1612d92bbc27SJoonsoo Kim } 1613b4b38223SJoonsoo Kim 1614ffe06786SMatthew Wilcox (Oracle) if (folio_test_large(folio)) { 16159933a0c8SJoonsoo Kim /* 16169933a0c8SJoonsoo Kim * clear __GFP_RECLAIM to make the migration callback 16179933a0c8SJoonsoo Kim * consistent with regular THP allocations. 16189933a0c8SJoonsoo Kim */ 16199933a0c8SJoonsoo Kim gfp_mask &= ~__GFP_RECLAIM; 1620b4b38223SJoonsoo Kim gfp_mask |= GFP_TRANSHUGE; 1621ffe06786SMatthew Wilcox (Oracle) order = folio_order(folio); 1622b4b38223SJoonsoo Kim } 1623ffe06786SMatthew Wilcox (Oracle) zidx = zone_idx(folio_zone(folio)); 162419fc7bedSJoonsoo Kim if (is_highmem_idx(zidx) || zidx == ZONE_MOVABLE) 1625b4b38223SJoonsoo Kim gfp_mask |= __GFP_HIGHMEM; 1626b4b38223SJoonsoo Kim 1627ffe06786SMatthew Wilcox (Oracle) new_folio = __folio_alloc(gfp_mask, order, nid, mtc->nmask); 1628b4b38223SJoonsoo Kim 1629ffe06786SMatthew Wilcox (Oracle) return &new_folio->page; 1630b4b38223SJoonsoo Kim } 1631b4b38223SJoonsoo Kim 1632742755a1SChristoph Lameter #ifdef CONFIG_NUMA 1633742755a1SChristoph Lameter 1634a49bd4d7SMichal Hocko static int store_status(int __user *status, int start, int value, int nr) 1635742755a1SChristoph Lameter { 1636a49bd4d7SMichal Hocko while (nr-- > 0) { 1637a49bd4d7SMichal Hocko if (put_user(value, status + start)) 1638a49bd4d7SMichal Hocko return -EFAULT; 1639a49bd4d7SMichal Hocko start++; 1640a49bd4d7SMichal Hocko } 1641742755a1SChristoph Lameter 1642a49bd4d7SMichal Hocko return 0; 1643a49bd4d7SMichal Hocko } 1644742755a1SChristoph Lameter 1645a49bd4d7SMichal Hocko static int do_move_pages_to_node(struct mm_struct *mm, 1646a49bd4d7SMichal Hocko struct list_head *pagelist, int node) 1647a49bd4d7SMichal Hocko { 1648a49bd4d7SMichal Hocko int err; 1649a0976311SJoonsoo Kim struct migration_target_control mtc = { 1650a0976311SJoonsoo Kim .nid = node, 1651a0976311SJoonsoo Kim .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, 1652a0976311SJoonsoo Kim }; 1653742755a1SChristoph Lameter 1654a0976311SJoonsoo Kim err = migrate_pages(pagelist, alloc_migration_target, NULL, 16555ac95884SYang Shi (unsigned long)&mtc, MIGRATE_SYNC, MR_SYSCALL, NULL); 1656a49bd4d7SMichal Hocko if (err) 1657a49bd4d7SMichal Hocko putback_movable_pages(pagelist); 1658a49bd4d7SMichal Hocko return err; 1659742755a1SChristoph Lameter } 1660742755a1SChristoph Lameter 1661742755a1SChristoph Lameter /* 1662a49bd4d7SMichal Hocko * Resolves the given address to a struct page, isolates it from the LRU and 1663a49bd4d7SMichal Hocko * puts it to the given pagelist. 1664e0153fc2SYang Shi * Returns: 1665e0153fc2SYang Shi * errno - if the page cannot be found/isolated 1666e0153fc2SYang Shi * 0 - when it doesn't have to be migrated because it is already on the 1667e0153fc2SYang Shi * target node 1668e0153fc2SYang Shi * 1 - when it has been queued 1669742755a1SChristoph Lameter */ 1670a49bd4d7SMichal Hocko static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, 1671a49bd4d7SMichal Hocko int node, struct list_head *pagelist, bool migrate_all) 1672742755a1SChristoph Lameter { 1673742755a1SChristoph Lameter struct vm_area_struct *vma; 1674742755a1SChristoph Lameter struct page *page; 1675a49bd4d7SMichal Hocko int err; 1676742755a1SChristoph Lameter 1677d8ed45c5SMichel Lespinasse mmap_read_lock(mm); 1678742755a1SChristoph Lameter err = -EFAULT; 1679cb1c37b1SMiaohe Lin vma = vma_lookup(mm, addr); 1680cb1c37b1SMiaohe Lin if (!vma || !vma_migratable(vma)) 1681a49bd4d7SMichal Hocko goto out; 1682742755a1SChristoph Lameter 1683d899844eSKirill A. Shutemov /* FOLL_DUMP to ignore special (like zero) pages */ 168487d2762eSMiaohe Lin page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); 168589f5b7daSLinus Torvalds 168689f5b7daSLinus Torvalds err = PTR_ERR(page); 168789f5b7daSLinus Torvalds if (IS_ERR(page)) 1688a49bd4d7SMichal Hocko goto out; 168989f5b7daSLinus Torvalds 1690742755a1SChristoph Lameter err = -ENOENT; 16913218f871SAlex Sierra if (!page || is_zone_device_page(page)) 1692a49bd4d7SMichal Hocko goto out; 1693742755a1SChristoph Lameter 1694a49bd4d7SMichal Hocko err = 0; 1695a49bd4d7SMichal Hocko if (page_to_nid(page) == node) 1696a49bd4d7SMichal Hocko goto out_putpage; 1697742755a1SChristoph Lameter 1698742755a1SChristoph Lameter err = -EACCES; 1699a49bd4d7SMichal Hocko if (page_mapcount(page) > 1 && !migrate_all) 1700a49bd4d7SMichal Hocko goto out_putpage; 1701742755a1SChristoph Lameter 1702e632a938SNaoya Horiguchi if (PageHuge(page)) { 1703e8db67ebSNaoya Horiguchi if (PageHead(page)) { 17047ce82f4cSMiaohe Lin err = isolate_hugetlb(page, pagelist); 17057ce82f4cSMiaohe Lin if (!err) 1706e0153fc2SYang Shi err = 1; 1707e8db67ebSNaoya Horiguchi } 1708a49bd4d7SMichal Hocko } else { 1709a49bd4d7SMichal Hocko struct page *head; 1710e632a938SNaoya Horiguchi 1711e8db67ebSNaoya Horiguchi head = compound_head(page); 1712e8db67ebSNaoya Horiguchi err = isolate_lru_page(head); 1713a49bd4d7SMichal Hocko if (err) 1714a49bd4d7SMichal Hocko goto out_putpage; 1715a49bd4d7SMichal Hocko 1716e0153fc2SYang Shi err = 1; 1717a49bd4d7SMichal Hocko list_add_tail(&head->lru, pagelist); 1718e8db67ebSNaoya Horiguchi mod_node_page_state(page_pgdat(head), 17199de4f22aSHuang Ying NR_ISOLATED_ANON + page_is_file_lru(head), 17206c357848SMatthew Wilcox (Oracle) thp_nr_pages(head)); 17216d9c285aSKOSAKI Motohiro } 1722a49bd4d7SMichal Hocko out_putpage: 1723742755a1SChristoph Lameter /* 1724742755a1SChristoph Lameter * Either remove the duplicate refcount from 1725742755a1SChristoph Lameter * isolate_lru_page() or drop the page ref if it was 1726742755a1SChristoph Lameter * not isolated. 1727742755a1SChristoph Lameter */ 1728742755a1SChristoph Lameter put_page(page); 1729a49bd4d7SMichal Hocko out: 1730d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 1731742755a1SChristoph Lameter return err; 1732742755a1SChristoph Lameter } 1733742755a1SChristoph Lameter 17347ca8783aSWei Yang static int move_pages_and_store_status(struct mm_struct *mm, int node, 17357ca8783aSWei Yang struct list_head *pagelist, int __user *status, 17367ca8783aSWei Yang int start, int i, unsigned long nr_pages) 17377ca8783aSWei Yang { 17387ca8783aSWei Yang int err; 17397ca8783aSWei Yang 17405d7ae891SWei Yang if (list_empty(pagelist)) 17415d7ae891SWei Yang return 0; 17425d7ae891SWei Yang 17437ca8783aSWei Yang err = do_move_pages_to_node(mm, pagelist, node); 17447ca8783aSWei Yang if (err) { 17457ca8783aSWei Yang /* 17467ca8783aSWei Yang * Positive err means the number of failed 17477ca8783aSWei Yang * pages to migrate. Since we are going to 17487ca8783aSWei Yang * abort and return the number of non-migrated 1749ab9dd4f8SLong Li * pages, so need to include the rest of the 17507ca8783aSWei Yang * nr_pages that have not been attempted as 17517ca8783aSWei Yang * well. 17527ca8783aSWei Yang */ 17537ca8783aSWei Yang if (err > 0) 17547ca8783aSWei Yang err += nr_pages - i - 1; 17557ca8783aSWei Yang return err; 17567ca8783aSWei Yang } 17577ca8783aSWei Yang return store_status(status, start, node, i - start); 17587ca8783aSWei Yang } 17597ca8783aSWei Yang 1760742755a1SChristoph Lameter /* 17615e9a0f02SBrice Goglin * Migrate an array of page address onto an array of nodes and fill 17625e9a0f02SBrice Goglin * the corresponding array of status. 17635e9a0f02SBrice Goglin */ 17643268c63eSChristoph Lameter static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, 17655e9a0f02SBrice Goglin unsigned long nr_pages, 17665e9a0f02SBrice Goglin const void __user * __user *pages, 17675e9a0f02SBrice Goglin const int __user *nodes, 17685e9a0f02SBrice Goglin int __user *status, int flags) 17695e9a0f02SBrice Goglin { 1770a49bd4d7SMichal Hocko int current_node = NUMA_NO_NODE; 1771a49bd4d7SMichal Hocko LIST_HEAD(pagelist); 1772a49bd4d7SMichal Hocko int start, i; 1773a49bd4d7SMichal Hocko int err = 0, err1; 177435282a2dSBrice Goglin 1775361a2a22SMinchan Kim lru_cache_disable(); 177635282a2dSBrice Goglin 1777a49bd4d7SMichal Hocko for (i = start = 0; i < nr_pages; i++) { 17785e9a0f02SBrice Goglin const void __user *p; 1779a49bd4d7SMichal Hocko unsigned long addr; 17805e9a0f02SBrice Goglin int node; 17815e9a0f02SBrice Goglin 17823140a227SBrice Goglin err = -EFAULT; 1783a49bd4d7SMichal Hocko if (get_user(p, pages + i)) 1784a49bd4d7SMichal Hocko goto out_flush; 1785a49bd4d7SMichal Hocko if (get_user(node, nodes + i)) 1786a49bd4d7SMichal Hocko goto out_flush; 1787057d3389SAndrey Konovalov addr = (unsigned long)untagged_addr(p); 17885e9a0f02SBrice Goglin 17895e9a0f02SBrice Goglin err = -ENODEV; 17906f5a55f1SLinus Torvalds if (node < 0 || node >= MAX_NUMNODES) 1791a49bd4d7SMichal Hocko goto out_flush; 1792389162c2SLai Jiangshan if (!node_state(node, N_MEMORY)) 1793a49bd4d7SMichal Hocko goto out_flush; 17945e9a0f02SBrice Goglin 17955e9a0f02SBrice Goglin err = -EACCES; 17965e9a0f02SBrice Goglin if (!node_isset(node, task_nodes)) 1797a49bd4d7SMichal Hocko goto out_flush; 17985e9a0f02SBrice Goglin 1799a49bd4d7SMichal Hocko if (current_node == NUMA_NO_NODE) { 1800a49bd4d7SMichal Hocko current_node = node; 1801a49bd4d7SMichal Hocko start = i; 1802a49bd4d7SMichal Hocko } else if (node != current_node) { 18037ca8783aSWei Yang err = move_pages_and_store_status(mm, current_node, 18047ca8783aSWei Yang &pagelist, status, start, i, nr_pages); 1805a49bd4d7SMichal Hocko if (err) 1806a49bd4d7SMichal Hocko goto out; 1807a49bd4d7SMichal Hocko start = i; 1808a49bd4d7SMichal Hocko current_node = node; 18095e9a0f02SBrice Goglin } 18105e9a0f02SBrice Goglin 1811a49bd4d7SMichal Hocko /* 1812a49bd4d7SMichal Hocko * Errors in the page lookup or isolation are not fatal and we simply 1813a49bd4d7SMichal Hocko * report them via status 1814a49bd4d7SMichal Hocko */ 1815a49bd4d7SMichal Hocko err = add_page_for_migration(mm, addr, current_node, 1816a49bd4d7SMichal Hocko &pagelist, flags & MPOL_MF_MOVE_ALL); 1817e0153fc2SYang Shi 1818d08221a0SWei Yang if (err > 0) { 1819e0153fc2SYang Shi /* The page is successfully queued for migration */ 1820e0153fc2SYang Shi continue; 1821e0153fc2SYang Shi } 18223140a227SBrice Goglin 1823d08221a0SWei Yang /* 182465462462SJohn Hubbard * The move_pages() man page does not have an -EEXIST choice, so 182565462462SJohn Hubbard * use -EFAULT instead. 182665462462SJohn Hubbard */ 182765462462SJohn Hubbard if (err == -EEXIST) 182865462462SJohn Hubbard err = -EFAULT; 182965462462SJohn Hubbard 183065462462SJohn Hubbard /* 1831d08221a0SWei Yang * If the page is already on the target node (!err), store the 1832d08221a0SWei Yang * node, otherwise, store the err. 1833d08221a0SWei Yang */ 1834d08221a0SWei Yang err = store_status(status, i, err ? : current_node, 1); 1835a49bd4d7SMichal Hocko if (err) 1836a49bd4d7SMichal Hocko goto out_flush; 18373140a227SBrice Goglin 18387ca8783aSWei Yang err = move_pages_and_store_status(mm, current_node, &pagelist, 18397ca8783aSWei Yang status, start, i, nr_pages); 1840a49bd4d7SMichal Hocko if (err) 1841a49bd4d7SMichal Hocko goto out; 1842a49bd4d7SMichal Hocko current_node = NUMA_NO_NODE; 18433140a227SBrice Goglin } 1844a49bd4d7SMichal Hocko out_flush: 1845a49bd4d7SMichal Hocko /* Make sure we do not overwrite the existing error */ 18467ca8783aSWei Yang err1 = move_pages_and_store_status(mm, current_node, &pagelist, 18477ca8783aSWei Yang status, start, i, nr_pages); 1848dfe9aa23SWei Yang if (err >= 0) 1849a49bd4d7SMichal Hocko err = err1; 18505e9a0f02SBrice Goglin out: 1851361a2a22SMinchan Kim lru_cache_enable(); 18525e9a0f02SBrice Goglin return err; 18535e9a0f02SBrice Goglin } 18545e9a0f02SBrice Goglin 18555e9a0f02SBrice Goglin /* 18562f007e74SBrice Goglin * Determine the nodes of an array of pages and store it in an array of status. 1857742755a1SChristoph Lameter */ 185880bba129SBrice Goglin static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, 185980bba129SBrice Goglin const void __user **pages, int *status) 1860742755a1SChristoph Lameter { 18612f007e74SBrice Goglin unsigned long i; 1862742755a1SChristoph Lameter 1863d8ed45c5SMichel Lespinasse mmap_read_lock(mm); 18642f007e74SBrice Goglin 18652f007e74SBrice Goglin for (i = 0; i < nr_pages; i++) { 186680bba129SBrice Goglin unsigned long addr = (unsigned long)(*pages); 186783156821SHaiyue Wang unsigned int foll_flags = FOLL_DUMP; 18682f007e74SBrice Goglin struct vm_area_struct *vma; 18692f007e74SBrice Goglin struct page *page; 1870c095adbcSKOSAKI Motohiro int err = -EFAULT; 18712f007e74SBrice Goglin 1872059b8b48SLiam Howlett vma = vma_lookup(mm, addr); 1873059b8b48SLiam Howlett if (!vma) 1874742755a1SChristoph Lameter goto set_status; 1875742755a1SChristoph Lameter 187683156821SHaiyue Wang /* Not all huge page follow APIs support 'FOLL_GET' */ 187783156821SHaiyue Wang if (!is_vm_hugetlb_page(vma)) 187883156821SHaiyue Wang foll_flags |= FOLL_GET; 187983156821SHaiyue Wang 1880d899844eSKirill A. Shutemov /* FOLL_DUMP to ignore special (like zero) pages */ 188183156821SHaiyue Wang page = follow_page(vma, addr, foll_flags); 188289f5b7daSLinus Torvalds 188389f5b7daSLinus Torvalds err = PTR_ERR(page); 188489f5b7daSLinus Torvalds if (IS_ERR(page)) 188589f5b7daSLinus Torvalds goto set_status; 188689f5b7daSLinus Torvalds 18873218f871SAlex Sierra if (page && !is_zone_device_page(page)) { 18884cd61484SMiaohe Lin err = page_to_nid(page); 188983156821SHaiyue Wang if (foll_flags & FOLL_GET) 18904cd61484SMiaohe Lin put_page(page); 18914cd61484SMiaohe Lin } else { 18924cd61484SMiaohe Lin err = -ENOENT; 18934cd61484SMiaohe Lin } 1894742755a1SChristoph Lameter set_status: 189580bba129SBrice Goglin *status = err; 189680bba129SBrice Goglin 189780bba129SBrice Goglin pages++; 189880bba129SBrice Goglin status++; 189980bba129SBrice Goglin } 190080bba129SBrice Goglin 1901d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 190280bba129SBrice Goglin } 190380bba129SBrice Goglin 19045b1b561bSArnd Bergmann static int get_compat_pages_array(const void __user *chunk_pages[], 19055b1b561bSArnd Bergmann const void __user * __user *pages, 19065b1b561bSArnd Bergmann unsigned long chunk_nr) 19075b1b561bSArnd Bergmann { 19085b1b561bSArnd Bergmann compat_uptr_t __user *pages32 = (compat_uptr_t __user *)pages; 19095b1b561bSArnd Bergmann compat_uptr_t p; 19105b1b561bSArnd Bergmann int i; 19115b1b561bSArnd Bergmann 19125b1b561bSArnd Bergmann for (i = 0; i < chunk_nr; i++) { 19135b1b561bSArnd Bergmann if (get_user(p, pages32 + i)) 19145b1b561bSArnd Bergmann return -EFAULT; 19155b1b561bSArnd Bergmann chunk_pages[i] = compat_ptr(p); 19165b1b561bSArnd Bergmann } 19175b1b561bSArnd Bergmann 19185b1b561bSArnd Bergmann return 0; 19195b1b561bSArnd Bergmann } 19205b1b561bSArnd Bergmann 192180bba129SBrice Goglin /* 192280bba129SBrice Goglin * Determine the nodes of a user array of pages and store it in 192380bba129SBrice Goglin * a user array of status. 192480bba129SBrice Goglin */ 192580bba129SBrice Goglin static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, 192680bba129SBrice Goglin const void __user * __user *pages, 192780bba129SBrice Goglin int __user *status) 192880bba129SBrice Goglin { 19293eefb826SMiaohe Lin #define DO_PAGES_STAT_CHUNK_NR 16UL 193080bba129SBrice Goglin const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR]; 193180bba129SBrice Goglin int chunk_status[DO_PAGES_STAT_CHUNK_NR]; 193280bba129SBrice Goglin 193387b8d1adSH. Peter Anvin while (nr_pages) { 19343eefb826SMiaohe Lin unsigned long chunk_nr = min(nr_pages, DO_PAGES_STAT_CHUNK_NR); 193587b8d1adSH. Peter Anvin 19365b1b561bSArnd Bergmann if (in_compat_syscall()) { 19375b1b561bSArnd Bergmann if (get_compat_pages_array(chunk_pages, pages, 19385b1b561bSArnd Bergmann chunk_nr)) 193987b8d1adSH. Peter Anvin break; 19405b1b561bSArnd Bergmann } else { 19415b1b561bSArnd Bergmann if (copy_from_user(chunk_pages, pages, 19425b1b561bSArnd Bergmann chunk_nr * sizeof(*chunk_pages))) 19435b1b561bSArnd Bergmann break; 19445b1b561bSArnd Bergmann } 194580bba129SBrice Goglin 194680bba129SBrice Goglin do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status); 194780bba129SBrice Goglin 194887b8d1adSH. Peter Anvin if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status))) 194987b8d1adSH. Peter Anvin break; 1950742755a1SChristoph Lameter 195187b8d1adSH. Peter Anvin pages += chunk_nr; 195287b8d1adSH. Peter Anvin status += chunk_nr; 195387b8d1adSH. Peter Anvin nr_pages -= chunk_nr; 195487b8d1adSH. Peter Anvin } 195587b8d1adSH. Peter Anvin return nr_pages ? -EFAULT : 0; 1956742755a1SChristoph Lameter } 1957742755a1SChristoph Lameter 19584dc200ceSMiaohe Lin static struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes) 19594dc200ceSMiaohe Lin { 19604dc200ceSMiaohe Lin struct task_struct *task; 19614dc200ceSMiaohe Lin struct mm_struct *mm; 19624dc200ceSMiaohe Lin 19634dc200ceSMiaohe Lin /* 19644dc200ceSMiaohe Lin * There is no need to check if current process has the right to modify 19654dc200ceSMiaohe Lin * the specified process when they are same. 19664dc200ceSMiaohe Lin */ 19674dc200ceSMiaohe Lin if (!pid) { 19684dc200ceSMiaohe Lin mmget(current->mm); 19694dc200ceSMiaohe Lin *mem_nodes = cpuset_mems_allowed(current); 19704dc200ceSMiaohe Lin return current->mm; 19714dc200ceSMiaohe Lin } 19724dc200ceSMiaohe Lin 19734dc200ceSMiaohe Lin /* Find the mm_struct */ 19744dc200ceSMiaohe Lin rcu_read_lock(); 19754dc200ceSMiaohe Lin task = find_task_by_vpid(pid); 19764dc200ceSMiaohe Lin if (!task) { 19774dc200ceSMiaohe Lin rcu_read_unlock(); 19784dc200ceSMiaohe Lin return ERR_PTR(-ESRCH); 19794dc200ceSMiaohe Lin } 19804dc200ceSMiaohe Lin get_task_struct(task); 19814dc200ceSMiaohe Lin 19824dc200ceSMiaohe Lin /* 19834dc200ceSMiaohe Lin * Check if this process has the right to modify the specified 19844dc200ceSMiaohe Lin * process. Use the regular "ptrace_may_access()" checks. 19854dc200ceSMiaohe Lin */ 19864dc200ceSMiaohe Lin if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) { 19874dc200ceSMiaohe Lin rcu_read_unlock(); 19884dc200ceSMiaohe Lin mm = ERR_PTR(-EPERM); 19894dc200ceSMiaohe Lin goto out; 19904dc200ceSMiaohe Lin } 19914dc200ceSMiaohe Lin rcu_read_unlock(); 19924dc200ceSMiaohe Lin 19934dc200ceSMiaohe Lin mm = ERR_PTR(security_task_movememory(task)); 19944dc200ceSMiaohe Lin if (IS_ERR(mm)) 19954dc200ceSMiaohe Lin goto out; 19964dc200ceSMiaohe Lin *mem_nodes = cpuset_mems_allowed(task); 19974dc200ceSMiaohe Lin mm = get_task_mm(task); 19984dc200ceSMiaohe Lin out: 19994dc200ceSMiaohe Lin put_task_struct(task); 20004dc200ceSMiaohe Lin if (!mm) 20014dc200ceSMiaohe Lin mm = ERR_PTR(-EINVAL); 20024dc200ceSMiaohe Lin return mm; 20034dc200ceSMiaohe Lin } 20044dc200ceSMiaohe Lin 2005742755a1SChristoph Lameter /* 2006742755a1SChristoph Lameter * Move a list of pages in the address space of the currently executing 2007742755a1SChristoph Lameter * process. 2008742755a1SChristoph Lameter */ 20097addf443SDominik Brodowski static int kernel_move_pages(pid_t pid, unsigned long nr_pages, 20107addf443SDominik Brodowski const void __user * __user *pages, 20117addf443SDominik Brodowski const int __user *nodes, 20127addf443SDominik Brodowski int __user *status, int flags) 2013742755a1SChristoph Lameter { 2014742755a1SChristoph Lameter struct mm_struct *mm; 20155e9a0f02SBrice Goglin int err; 20163268c63eSChristoph Lameter nodemask_t task_nodes; 2017742755a1SChristoph Lameter 2018742755a1SChristoph Lameter /* Check flags */ 2019742755a1SChristoph Lameter if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) 2020742755a1SChristoph Lameter return -EINVAL; 2021742755a1SChristoph Lameter 2022742755a1SChristoph Lameter if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE)) 2023742755a1SChristoph Lameter return -EPERM; 2024742755a1SChristoph Lameter 20254dc200ceSMiaohe Lin mm = find_mm_struct(pid, &task_nodes); 20264dc200ceSMiaohe Lin if (IS_ERR(mm)) 20274dc200ceSMiaohe Lin return PTR_ERR(mm); 20286e8b09eaSSasha Levin 20293268c63eSChristoph Lameter if (nodes) 20303268c63eSChristoph Lameter err = do_pages_move(mm, task_nodes, nr_pages, pages, 20313268c63eSChristoph Lameter nodes, status, flags); 20323268c63eSChristoph Lameter else 20335e9a0f02SBrice Goglin err = do_pages_stat(mm, nr_pages, pages, status); 20343268c63eSChristoph Lameter 20353268c63eSChristoph Lameter mmput(mm); 20363268c63eSChristoph Lameter return err; 2037742755a1SChristoph Lameter } 2038742755a1SChristoph Lameter 20397addf443SDominik Brodowski SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages, 20407addf443SDominik Brodowski const void __user * __user *, pages, 20417addf443SDominik Brodowski const int __user *, nodes, 20427addf443SDominik Brodowski int __user *, status, int, flags) 20437addf443SDominik Brodowski { 20447addf443SDominik Brodowski return kernel_move_pages(pid, nr_pages, pages, nodes, status, flags); 20457addf443SDominik Brodowski } 20467addf443SDominik Brodowski 20477039e1dbSPeter Zijlstra #ifdef CONFIG_NUMA_BALANCING 20487039e1dbSPeter Zijlstra /* 20497039e1dbSPeter Zijlstra * Returns true if this is a safe migration target node for misplaced NUMA 2050bc53008eSWei Yang * pages. Currently it only checks the watermarks which is crude. 20517039e1dbSPeter Zijlstra */ 20527039e1dbSPeter Zijlstra static bool migrate_balanced_pgdat(struct pglist_data *pgdat, 20533abef4e6SMel Gorman unsigned long nr_migrate_pages) 20547039e1dbSPeter Zijlstra { 20557039e1dbSPeter Zijlstra int z; 2056599d0c95SMel Gorman 20577039e1dbSPeter Zijlstra for (z = pgdat->nr_zones - 1; z >= 0; z--) { 20587039e1dbSPeter Zijlstra struct zone *zone = pgdat->node_zones + z; 20597039e1dbSPeter Zijlstra 2060bc53008eSWei Yang if (!managed_zone(zone)) 20617039e1dbSPeter Zijlstra continue; 20627039e1dbSPeter Zijlstra 20637039e1dbSPeter Zijlstra /* Avoid waking kswapd by allocating pages_to_migrate pages. */ 20647039e1dbSPeter Zijlstra if (!zone_watermark_ok(zone, 0, 20657039e1dbSPeter Zijlstra high_wmark_pages(zone) + 20667039e1dbSPeter Zijlstra nr_migrate_pages, 2067bfe9d006SHuang Ying ZONE_MOVABLE, 0)) 20687039e1dbSPeter Zijlstra continue; 20697039e1dbSPeter Zijlstra return true; 20707039e1dbSPeter Zijlstra } 20717039e1dbSPeter Zijlstra return false; 20727039e1dbSPeter Zijlstra } 20737039e1dbSPeter Zijlstra 20747039e1dbSPeter Zijlstra static struct page *alloc_misplaced_dst_page(struct page *page, 2075666feb21SMichal Hocko unsigned long data) 20767039e1dbSPeter Zijlstra { 20777039e1dbSPeter Zijlstra int nid = (int) data; 2078c185e494SMatthew Wilcox (Oracle) int order = compound_order(page); 2079c185e494SMatthew Wilcox (Oracle) gfp_t gfp = __GFP_THISNODE; 2080c185e494SMatthew Wilcox (Oracle) struct folio *new; 20817039e1dbSPeter Zijlstra 2082c185e494SMatthew Wilcox (Oracle) if (order > 0) 2083c185e494SMatthew Wilcox (Oracle) gfp |= GFP_TRANSHUGE_LIGHT; 2084c185e494SMatthew Wilcox (Oracle) else { 2085c185e494SMatthew Wilcox (Oracle) gfp |= GFP_HIGHUSER_MOVABLE | __GFP_NOMEMALLOC | __GFP_NORETRY | 2086c185e494SMatthew Wilcox (Oracle) __GFP_NOWARN; 2087c185e494SMatthew Wilcox (Oracle) gfp &= ~__GFP_RECLAIM; 20887039e1dbSPeter Zijlstra } 2089c185e494SMatthew Wilcox (Oracle) new = __folio_alloc_node(gfp, order, nid); 20907039e1dbSPeter Zijlstra 2091c185e494SMatthew Wilcox (Oracle) return &new->page; 2092c5b5a3ddSYang Shi } 2093c5b5a3ddSYang Shi 20941c30e017SMel Gorman static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) 2095b32967ffSMel Gorman { 20962b9b624fSBaolin Wang int nr_pages = thp_nr_pages(page); 2097c574bbe9SHuang Ying int order = compound_order(page); 2098b32967ffSMel Gorman 2099c574bbe9SHuang Ying VM_BUG_ON_PAGE(order && !PageTransHuge(page), page); 21003abef4e6SMel Gorman 2101662aeea7SYang Shi /* Do not migrate THP mapped by multiple processes */ 2102662aeea7SYang Shi if (PageTransHuge(page) && total_mapcount(page) > 1) 2103662aeea7SYang Shi return 0; 2104662aeea7SYang Shi 2105b32967ffSMel Gorman /* Avoid migrating to a node that is nearly full */ 2106c574bbe9SHuang Ying if (!migrate_balanced_pgdat(pgdat, nr_pages)) { 2107c574bbe9SHuang Ying int z; 2108c574bbe9SHuang Ying 2109c574bbe9SHuang Ying if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING)) 2110340ef390SHugh Dickins return 0; 2111c574bbe9SHuang Ying for (z = pgdat->nr_zones - 1; z >= 0; z--) { 2112bc53008eSWei Yang if (managed_zone(pgdat->node_zones + z)) 2113c574bbe9SHuang Ying break; 2114c574bbe9SHuang Ying } 2115c574bbe9SHuang Ying wakeup_kswapd(pgdat->node_zones + z, 0, order, ZONE_MOVABLE); 2116c574bbe9SHuang Ying return 0; 2117c574bbe9SHuang Ying } 2118b32967ffSMel Gorman 2119340ef390SHugh Dickins if (isolate_lru_page(page)) 2120340ef390SHugh Dickins return 0; 2121340ef390SHugh Dickins 2122b75454e1SMiaohe Lin mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_is_file_lru(page), 21232b9b624fSBaolin Wang nr_pages); 2124b32967ffSMel Gorman 2125b32967ffSMel Gorman /* 2126340ef390SHugh Dickins * Isolating the page has taken another reference, so the 2127340ef390SHugh Dickins * caller's reference can be safely dropped without the page 2128340ef390SHugh Dickins * disappearing underneath us during migration. 2129b32967ffSMel Gorman */ 2130b32967ffSMel Gorman put_page(page); 2131340ef390SHugh Dickins return 1; 2132b32967ffSMel Gorman } 2133b32967ffSMel Gorman 2134a8f60772SMel Gorman /* 21357039e1dbSPeter Zijlstra * Attempt to migrate a misplaced page to the specified destination 21367039e1dbSPeter Zijlstra * node. Caller is expected to have an elevated reference count on 21377039e1dbSPeter Zijlstra * the page that will be dropped by this function before returning. 21387039e1dbSPeter Zijlstra */ 21391bc115d8SMel Gorman int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, 21401bc115d8SMel Gorman int node) 21417039e1dbSPeter Zijlstra { 2142a8f60772SMel Gorman pg_data_t *pgdat = NODE_DATA(node); 2143340ef390SHugh Dickins int isolated; 2144b32967ffSMel Gorman int nr_remaining; 2145e39bb6beSHuang Ying unsigned int nr_succeeded; 21467039e1dbSPeter Zijlstra LIST_HEAD(migratepages); 2147b5916c02SAneesh Kumar K.V int nr_pages = thp_nr_pages(page); 2148c5b5a3ddSYang Shi 2149c5b5a3ddSYang Shi /* 21501bc115d8SMel Gorman * Don't migrate file pages that are mapped in multiple processes 21511bc115d8SMel Gorman * with execute permissions as they are probably shared libraries. 21527039e1dbSPeter Zijlstra */ 21537ee820eeSMiaohe Lin if (page_mapcount(page) != 1 && page_is_file_lru(page) && 21547ee820eeSMiaohe Lin (vma->vm_flags & VM_EXEC)) 21557039e1dbSPeter Zijlstra goto out; 21567039e1dbSPeter Zijlstra 2157a8f60772SMel Gorman /* 215809a913a7SMel Gorman * Also do not migrate dirty pages as not all filesystems can move 215909a913a7SMel Gorman * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. 216009a913a7SMel Gorman */ 21619de4f22aSHuang Ying if (page_is_file_lru(page) && PageDirty(page)) 216209a913a7SMel Gorman goto out; 216309a913a7SMel Gorman 2164b32967ffSMel Gorman isolated = numamigrate_isolate_page(pgdat, page); 2165b32967ffSMel Gorman if (!isolated) 21667039e1dbSPeter Zijlstra goto out; 21677039e1dbSPeter Zijlstra 21687039e1dbSPeter Zijlstra list_add(&page->lru, &migratepages); 2169c185e494SMatthew Wilcox (Oracle) nr_remaining = migrate_pages(&migratepages, alloc_misplaced_dst_page, 2170c185e494SMatthew Wilcox (Oracle) NULL, node, MIGRATE_ASYNC, 2171c185e494SMatthew Wilcox (Oracle) MR_NUMA_MISPLACED, &nr_succeeded); 21727039e1dbSPeter Zijlstra if (nr_remaining) { 217359c82b70SJoonsoo Kim if (!list_empty(&migratepages)) { 217459c82b70SJoonsoo Kim list_del(&page->lru); 2175c5fc5c3aSYang Shi mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + 2176c5fc5c3aSYang Shi page_is_file_lru(page), -nr_pages); 217759c82b70SJoonsoo Kim putback_lru_page(page); 217859c82b70SJoonsoo Kim } 21797039e1dbSPeter Zijlstra isolated = 0; 2180e39bb6beSHuang Ying } 2181e39bb6beSHuang Ying if (nr_succeeded) { 2182e39bb6beSHuang Ying count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded); 2183e39bb6beSHuang Ying if (!node_is_toptier(page_to_nid(page)) && node_is_toptier(node)) 2184e39bb6beSHuang Ying mod_node_page_state(pgdat, PGPROMOTE_SUCCESS, 2185e39bb6beSHuang Ying nr_succeeded); 2186e39bb6beSHuang Ying } 21877039e1dbSPeter Zijlstra BUG_ON(!list_empty(&migratepages)); 21887039e1dbSPeter Zijlstra return isolated; 2189340ef390SHugh Dickins 2190340ef390SHugh Dickins out: 2191340ef390SHugh Dickins put_page(page); 2192340ef390SHugh Dickins return 0; 21937039e1dbSPeter Zijlstra } 2194220018d3SMel Gorman #endif /* CONFIG_NUMA_BALANCING */ 21958763cb45SJérôme Glisse 2196dcee9bf5SHuang Ying /* 2197dcee9bf5SHuang Ying * node_demotion[] example: 2198dcee9bf5SHuang Ying * 2199dcee9bf5SHuang Ying * Consider a system with two sockets. Each socket has 2200dcee9bf5SHuang Ying * three classes of memory attached: fast, medium and slow. 2201dcee9bf5SHuang Ying * Each memory class is placed in its own NUMA node. The 2202dcee9bf5SHuang Ying * CPUs are placed in the node with the "fast" memory. The 2203dcee9bf5SHuang Ying * 6 NUMA nodes (0-5) might be split among the sockets like 2204dcee9bf5SHuang Ying * this: 2205dcee9bf5SHuang Ying * 2206dcee9bf5SHuang Ying * Socket A: 0, 1, 2 2207dcee9bf5SHuang Ying * Socket B: 3, 4, 5 2208dcee9bf5SHuang Ying * 2209dcee9bf5SHuang Ying * When Node 0 fills up, its memory should be migrated to 2210dcee9bf5SHuang Ying * Node 1. When Node 1 fills up, it should be migrated to 2211dcee9bf5SHuang Ying * Node 2. The migration path start on the nodes with the 2212dcee9bf5SHuang Ying * processors (since allocations default to this node) and 2213dcee9bf5SHuang Ying * fast memory, progress through medium and end with the 2214dcee9bf5SHuang Ying * slow memory: 2215dcee9bf5SHuang Ying * 2216dcee9bf5SHuang Ying * 0 -> 1 -> 2 -> stop 2217dcee9bf5SHuang Ying * 3 -> 4 -> 5 -> stop 2218dcee9bf5SHuang Ying * 2219dcee9bf5SHuang Ying * This is represented in the node_demotion[] like this: 2220dcee9bf5SHuang Ying * 2221dcee9bf5SHuang Ying * { nr=1, nodes[0]=1 }, // Node 0 migrates to 1 2222dcee9bf5SHuang Ying * { nr=1, nodes[0]=2 }, // Node 1 migrates to 2 2223dcee9bf5SHuang Ying * { nr=0, nodes[0]=-1 }, // Node 2 does not migrate 2224dcee9bf5SHuang Ying * { nr=1, nodes[0]=4 }, // Node 3 migrates to 4 2225dcee9bf5SHuang Ying * { nr=1, nodes[0]=5 }, // Node 4 migrates to 5 2226dcee9bf5SHuang Ying * { nr=0, nodes[0]=-1 }, // Node 5 does not migrate 2227dcee9bf5SHuang Ying * 2228dcee9bf5SHuang Ying * Moreover some systems may have multiple slow memory nodes. 2229dcee9bf5SHuang Ying * Suppose a system has one socket with 3 memory nodes, node 0 2230dcee9bf5SHuang Ying * is fast memory type, and node 1/2 both are slow memory 2231dcee9bf5SHuang Ying * type, and the distance between fast memory node and slow 2232dcee9bf5SHuang Ying * memory node is same. So the migration path should be: 2233dcee9bf5SHuang Ying * 2234dcee9bf5SHuang Ying * 0 -> 1/2 -> stop 2235dcee9bf5SHuang Ying * 2236dcee9bf5SHuang Ying * This is represented in the node_demotion[] like this: 2237dcee9bf5SHuang Ying * { nr=2, {nodes[0]=1, nodes[1]=2} }, // Node 0 migrates to node 1 and node 2 2238dcee9bf5SHuang Ying * { nr=0, nodes[0]=-1, }, // Node 1 dose not migrate 2239dcee9bf5SHuang Ying * { nr=0, nodes[0]=-1, }, // Node 2 does not migrate 2240dcee9bf5SHuang Ying */ 2241dcee9bf5SHuang Ying 2242dcee9bf5SHuang Ying /* 2243dcee9bf5SHuang Ying * Writes to this array occur without locking. Cycles are 2244dcee9bf5SHuang Ying * not allowed: Node X demotes to Y which demotes to X... 2245dcee9bf5SHuang Ying * 2246dcee9bf5SHuang Ying * If multiple reads are performed, a single rcu_read_lock() 2247dcee9bf5SHuang Ying * must be held over all reads to ensure that no cycles are 2248dcee9bf5SHuang Ying * observed. 2249dcee9bf5SHuang Ying */ 2250dcee9bf5SHuang Ying #define DEFAULT_DEMOTION_TARGET_NODES 15 2251dcee9bf5SHuang Ying 2252dcee9bf5SHuang Ying #if MAX_NUMNODES < DEFAULT_DEMOTION_TARGET_NODES 2253dcee9bf5SHuang Ying #define DEMOTION_TARGET_NODES (MAX_NUMNODES - 1) 2254dcee9bf5SHuang Ying #else 2255dcee9bf5SHuang Ying #define DEMOTION_TARGET_NODES DEFAULT_DEMOTION_TARGET_NODES 2256dcee9bf5SHuang Ying #endif 2257dcee9bf5SHuang Ying 2258dcee9bf5SHuang Ying struct demotion_nodes { 2259dcee9bf5SHuang Ying unsigned short nr; 2260dcee9bf5SHuang Ying short nodes[DEMOTION_TARGET_NODES]; 2261dcee9bf5SHuang Ying }; 2262dcee9bf5SHuang Ying 2263dcee9bf5SHuang Ying static struct demotion_nodes *node_demotion __read_mostly; 2264dcee9bf5SHuang Ying 2265dcee9bf5SHuang Ying /** 2266dcee9bf5SHuang Ying * next_demotion_node() - Get the next node in the demotion path 2267dcee9bf5SHuang Ying * @node: The starting node to lookup the next node 2268dcee9bf5SHuang Ying * 2269dcee9bf5SHuang Ying * Return: node id for next memory node in the demotion path hierarchy 2270dcee9bf5SHuang Ying * from @node; NUMA_NO_NODE if @node is terminal. This does not keep 2271dcee9bf5SHuang Ying * @node online or guarantee that it *continues* to be the next demotion 2272dcee9bf5SHuang Ying * target. 2273dcee9bf5SHuang Ying */ 2274dcee9bf5SHuang Ying int next_demotion_node(int node) 2275dcee9bf5SHuang Ying { 2276dcee9bf5SHuang Ying struct demotion_nodes *nd; 2277dcee9bf5SHuang Ying unsigned short target_nr, index; 2278dcee9bf5SHuang Ying int target; 2279dcee9bf5SHuang Ying 2280dcee9bf5SHuang Ying if (!node_demotion) 2281dcee9bf5SHuang Ying return NUMA_NO_NODE; 2282dcee9bf5SHuang Ying 2283dcee9bf5SHuang Ying nd = &node_demotion[node]; 2284dcee9bf5SHuang Ying 2285dcee9bf5SHuang Ying /* 2286dcee9bf5SHuang Ying * node_demotion[] is updated without excluding this 2287dcee9bf5SHuang Ying * function from running. RCU doesn't provide any 2288dcee9bf5SHuang Ying * compiler barriers, so the READ_ONCE() is required 2289dcee9bf5SHuang Ying * to avoid compiler reordering or read merging. 2290dcee9bf5SHuang Ying * 2291dcee9bf5SHuang Ying * Make sure to use RCU over entire code blocks if 2292dcee9bf5SHuang Ying * node_demotion[] reads need to be consistent. 2293dcee9bf5SHuang Ying */ 2294dcee9bf5SHuang Ying rcu_read_lock(); 2295dcee9bf5SHuang Ying target_nr = READ_ONCE(nd->nr); 2296dcee9bf5SHuang Ying 2297dcee9bf5SHuang Ying switch (target_nr) { 2298dcee9bf5SHuang Ying case 0: 2299dcee9bf5SHuang Ying target = NUMA_NO_NODE; 2300dcee9bf5SHuang Ying goto out; 2301dcee9bf5SHuang Ying case 1: 2302dcee9bf5SHuang Ying index = 0; 2303dcee9bf5SHuang Ying break; 2304dcee9bf5SHuang Ying default: 2305dcee9bf5SHuang Ying /* 2306dcee9bf5SHuang Ying * If there are multiple target nodes, just select one 2307dcee9bf5SHuang Ying * target node randomly. 2308dcee9bf5SHuang Ying * 2309dcee9bf5SHuang Ying * In addition, we can also use round-robin to select 2310dcee9bf5SHuang Ying * target node, but we should introduce another variable 2311dcee9bf5SHuang Ying * for node_demotion[] to record last selected target node, 2312dcee9bf5SHuang Ying * that may cause cache ping-pong due to the changing of 2313dcee9bf5SHuang Ying * last target node. Or introducing per-cpu data to avoid 2314dcee9bf5SHuang Ying * caching issue, which seems more complicated. So selecting 2315dcee9bf5SHuang Ying * target node randomly seems better until now. 2316dcee9bf5SHuang Ying */ 2317dcee9bf5SHuang Ying index = get_random_int() % target_nr; 2318dcee9bf5SHuang Ying break; 2319dcee9bf5SHuang Ying } 2320dcee9bf5SHuang Ying 2321dcee9bf5SHuang Ying target = READ_ONCE(nd->nodes[index]); 2322dcee9bf5SHuang Ying 2323dcee9bf5SHuang Ying out: 2324dcee9bf5SHuang Ying rcu_read_unlock(); 2325dcee9bf5SHuang Ying return target; 2326dcee9bf5SHuang Ying } 2327dcee9bf5SHuang Ying 232879c28a41SDave Hansen /* Disable reclaim-based migration. */ 232979c28a41SDave Hansen static void __disable_all_migrate_targets(void) 233079c28a41SDave Hansen { 2331ac16ec83SBaolin Wang int node, i; 233279c28a41SDave Hansen 2333ac16ec83SBaolin Wang if (!node_demotion) 2334ac16ec83SBaolin Wang return; 2335ac16ec83SBaolin Wang 2336ac16ec83SBaolin Wang for_each_online_node(node) { 2337ac16ec83SBaolin Wang node_demotion[node].nr = 0; 2338ac16ec83SBaolin Wang for (i = 0; i < DEMOTION_TARGET_NODES; i++) 2339ac16ec83SBaolin Wang node_demotion[node].nodes[i] = NUMA_NO_NODE; 2340ac16ec83SBaolin Wang } 234179c28a41SDave Hansen } 234279c28a41SDave Hansen 234379c28a41SDave Hansen static void disable_all_migrate_targets(void) 234479c28a41SDave Hansen { 234579c28a41SDave Hansen __disable_all_migrate_targets(); 234679c28a41SDave Hansen 234779c28a41SDave Hansen /* 234879c28a41SDave Hansen * Ensure that the "disable" is visible across the system. 234979c28a41SDave Hansen * Readers will see either a combination of before+disable 235079c28a41SDave Hansen * state or disable+after. They will never see before and 235179c28a41SDave Hansen * after state together. 235279c28a41SDave Hansen * 235379c28a41SDave Hansen * The before+after state together might have cycles and 235479c28a41SDave Hansen * could cause readers to do things like loop until this 235579c28a41SDave Hansen * function finishes. This ensures they can only see a 235679c28a41SDave Hansen * single "bad" read and would, for instance, only loop 235779c28a41SDave Hansen * once. 235879c28a41SDave Hansen */ 235979c28a41SDave Hansen synchronize_rcu(); 236079c28a41SDave Hansen } 236179c28a41SDave Hansen 236279c28a41SDave Hansen /* 236379c28a41SDave Hansen * Find an automatic demotion target for 'node'. 236479c28a41SDave Hansen * Failing here is OK. It might just indicate 236579c28a41SDave Hansen * being at the end of a chain. 236679c28a41SDave Hansen */ 2367ac16ec83SBaolin Wang static int establish_migrate_target(int node, nodemask_t *used, 2368ac16ec83SBaolin Wang int best_distance) 236979c28a41SDave Hansen { 2370ac16ec83SBaolin Wang int migration_target, index, val; 2371ac16ec83SBaolin Wang struct demotion_nodes *nd; 237279c28a41SDave Hansen 2373ac16ec83SBaolin Wang if (!node_demotion) 237479c28a41SDave Hansen return NUMA_NO_NODE; 237579c28a41SDave Hansen 2376ac16ec83SBaolin Wang nd = &node_demotion[node]; 2377ac16ec83SBaolin Wang 237879c28a41SDave Hansen migration_target = find_next_best_node(node, used); 237979c28a41SDave Hansen if (migration_target == NUMA_NO_NODE) 238079c28a41SDave Hansen return NUMA_NO_NODE; 238179c28a41SDave Hansen 2382ac16ec83SBaolin Wang /* 2383ac16ec83SBaolin Wang * If the node has been set a migration target node before, 2384ac16ec83SBaolin Wang * which means it's the best distance between them. Still 2385ac16ec83SBaolin Wang * check if this node can be demoted to other target nodes 2386ac16ec83SBaolin Wang * if they have a same best distance. 2387ac16ec83SBaolin Wang */ 2388ac16ec83SBaolin Wang if (best_distance != -1) { 2389ac16ec83SBaolin Wang val = node_distance(node, migration_target); 2390ac16ec83SBaolin Wang if (val > best_distance) 2391fc89213aSHuang Ying goto out_clear; 2392ac16ec83SBaolin Wang } 2393ac16ec83SBaolin Wang 2394ac16ec83SBaolin Wang index = nd->nr; 2395ac16ec83SBaolin Wang if (WARN_ONCE(index >= DEMOTION_TARGET_NODES, 2396ac16ec83SBaolin Wang "Exceeds maximum demotion target nodes\n")) 2397fc89213aSHuang Ying goto out_clear; 2398ac16ec83SBaolin Wang 2399ac16ec83SBaolin Wang nd->nodes[index] = migration_target; 2400ac16ec83SBaolin Wang nd->nr++; 240179c28a41SDave Hansen 240279c28a41SDave Hansen return migration_target; 2403fc89213aSHuang Ying out_clear: 2404fc89213aSHuang Ying node_clear(migration_target, *used); 2405fc89213aSHuang Ying return NUMA_NO_NODE; 240679c28a41SDave Hansen } 240779c28a41SDave Hansen 240879c28a41SDave Hansen /* 240979c28a41SDave Hansen * When memory fills up on a node, memory contents can be 241079c28a41SDave Hansen * automatically migrated to another node instead of 241179c28a41SDave Hansen * discarded at reclaim. 241279c28a41SDave Hansen * 241379c28a41SDave Hansen * Establish a "migration path" which will start at nodes 241479c28a41SDave Hansen * with CPUs and will follow the priorities used to build the 241579c28a41SDave Hansen * page allocator zonelists. 241679c28a41SDave Hansen * 241779c28a41SDave Hansen * The difference here is that cycles must be avoided. If 241879c28a41SDave Hansen * node0 migrates to node1, then neither node1, nor anything 2419ac16ec83SBaolin Wang * node1 migrates to can migrate to node0. Also one node can 2420ac16ec83SBaolin Wang * be migrated to multiple nodes if the target nodes all have 2421ac16ec83SBaolin Wang * a same best-distance against the source node. 242279c28a41SDave Hansen * 242379c28a41SDave Hansen * This function can run simultaneously with readers of 242479c28a41SDave Hansen * node_demotion[]. However, it can not run simultaneously 242579c28a41SDave Hansen * with itself. Exclusion is provided by memory hotplug events 242679c28a41SDave Hansen * being single-threaded. 242779c28a41SDave Hansen */ 242879c28a41SDave Hansen static void __set_migration_target_nodes(void) 242979c28a41SDave Hansen { 243091925ab8SMiaohe Lin nodemask_t next_pass; 243191925ab8SMiaohe Lin nodemask_t this_pass; 243279c28a41SDave Hansen nodemask_t used_targets = NODE_MASK_NONE; 2433ac16ec83SBaolin Wang int node, best_distance; 243479c28a41SDave Hansen 243579c28a41SDave Hansen /* 243679c28a41SDave Hansen * Avoid any oddities like cycles that could occur 243779c28a41SDave Hansen * from changes in the topology. This will leave 243879c28a41SDave Hansen * a momentary gap when migration is disabled. 243979c28a41SDave Hansen */ 244079c28a41SDave Hansen disable_all_migrate_targets(); 244179c28a41SDave Hansen 244279c28a41SDave Hansen /* 244379c28a41SDave Hansen * Allocations go close to CPUs, first. Assume that 244479c28a41SDave Hansen * the migration path starts at the nodes with CPUs. 244579c28a41SDave Hansen */ 244679c28a41SDave Hansen next_pass = node_states[N_CPU]; 244779c28a41SDave Hansen again: 244879c28a41SDave Hansen this_pass = next_pass; 244979c28a41SDave Hansen next_pass = NODE_MASK_NONE; 245079c28a41SDave Hansen /* 245179c28a41SDave Hansen * To avoid cycles in the migration "graph", ensure 245279c28a41SDave Hansen * that migration sources are not future targets by 245379c28a41SDave Hansen * setting them in 'used_targets'. Do this only 245479c28a41SDave Hansen * once per pass so that multiple source nodes can 245579c28a41SDave Hansen * share a target node. 245679c28a41SDave Hansen * 245779c28a41SDave Hansen * 'used_targets' will become unavailable in future 245879c28a41SDave Hansen * passes. This limits some opportunities for 245979c28a41SDave Hansen * multiple source nodes to share a destination. 246079c28a41SDave Hansen */ 246179c28a41SDave Hansen nodes_or(used_targets, used_targets, this_pass); 2462ac16ec83SBaolin Wang 246379c28a41SDave Hansen for_each_node_mask(node, this_pass) { 2464ac16ec83SBaolin Wang best_distance = -1; 2465ac16ec83SBaolin Wang 2466ac16ec83SBaolin Wang /* 2467ac16ec83SBaolin Wang * Try to set up the migration path for the node, and the target 2468ac16ec83SBaolin Wang * migration nodes can be multiple, so doing a loop to find all 2469ac16ec83SBaolin Wang * the target nodes if they all have a best node distance. 2470ac16ec83SBaolin Wang */ 2471ac16ec83SBaolin Wang do { 2472ac16ec83SBaolin Wang int target_node = 2473ac16ec83SBaolin Wang establish_migrate_target(node, &used_targets, 2474ac16ec83SBaolin Wang best_distance); 247579c28a41SDave Hansen 247679c28a41SDave Hansen if (target_node == NUMA_NO_NODE) 2477ac16ec83SBaolin Wang break; 2478ac16ec83SBaolin Wang 2479ac16ec83SBaolin Wang if (best_distance == -1) 2480ac16ec83SBaolin Wang best_distance = node_distance(node, target_node); 248179c28a41SDave Hansen 248279c28a41SDave Hansen /* 248379c28a41SDave Hansen * Visit targets from this pass in the next pass. 248479c28a41SDave Hansen * Eventually, every node will have been part of 248579c28a41SDave Hansen * a pass, and will become set in 'used_targets'. 248679c28a41SDave Hansen */ 248779c28a41SDave Hansen node_set(target_node, next_pass); 2488ac16ec83SBaolin Wang } while (1); 248979c28a41SDave Hansen } 249079c28a41SDave Hansen /* 249179c28a41SDave Hansen * 'next_pass' contains nodes which became migration 249279c28a41SDave Hansen * targets in this pass. Make additional passes until 249379c28a41SDave Hansen * no more migrations targets are available. 249479c28a41SDave Hansen */ 249579c28a41SDave Hansen if (!nodes_empty(next_pass)) 249679c28a41SDave Hansen goto again; 249779c28a41SDave Hansen } 249879c28a41SDave Hansen 249979c28a41SDave Hansen /* 250079c28a41SDave Hansen * For callers that do not hold get_online_mems() already. 250179c28a41SDave Hansen */ 2502734c1570SOscar Salvador void set_migration_target_nodes(void) 250379c28a41SDave Hansen { 250479c28a41SDave Hansen get_online_mems(); 250579c28a41SDave Hansen __set_migration_target_nodes(); 250679c28a41SDave Hansen put_online_mems(); 250779c28a41SDave Hansen } 2508884a6e5dSDave Hansen 2509884a6e5dSDave Hansen /* 2510884a6e5dSDave Hansen * This leaves migrate-on-reclaim transiently disabled between 2511884a6e5dSDave Hansen * the MEM_GOING_OFFLINE and MEM_OFFLINE events. This runs 2512884a6e5dSDave Hansen * whether reclaim-based migration is enabled or not, which 2513884a6e5dSDave Hansen * ensures that the user can turn reclaim-based migration at 2514884a6e5dSDave Hansen * any time without needing to recalculate migration targets. 2515884a6e5dSDave Hansen * 2516884a6e5dSDave Hansen * These callbacks already hold get_online_mems(). That is why 2517884a6e5dSDave Hansen * __set_migration_target_nodes() can be used as opposed to 2518884a6e5dSDave Hansen * set_migration_target_nodes(). 2519884a6e5dSDave Hansen */ 25207d6e2d96SOscar Salvador #ifdef CONFIG_MEMORY_HOTPLUG 2521884a6e5dSDave Hansen static int __meminit migrate_on_reclaim_callback(struct notifier_block *self, 2522295be91fSDave Hansen unsigned long action, void *_arg) 2523884a6e5dSDave Hansen { 2524295be91fSDave Hansen struct memory_notify *arg = _arg; 2525295be91fSDave Hansen 2526295be91fSDave Hansen /* 2527295be91fSDave Hansen * Only update the node migration order when a node is 2528295be91fSDave Hansen * changing status, like online->offline. This avoids 2529295be91fSDave Hansen * the overhead of synchronize_rcu() in most cases. 2530295be91fSDave Hansen */ 2531295be91fSDave Hansen if (arg->status_change_nid < 0) 2532295be91fSDave Hansen return notifier_from_errno(0); 2533295be91fSDave Hansen 2534884a6e5dSDave Hansen switch (action) { 2535884a6e5dSDave Hansen case MEM_GOING_OFFLINE: 2536884a6e5dSDave Hansen /* 2537884a6e5dSDave Hansen * Make sure there are not transient states where 2538884a6e5dSDave Hansen * an offline node is a migration target. This 2539884a6e5dSDave Hansen * will leave migration disabled until the offline 2540884a6e5dSDave Hansen * completes and the MEM_OFFLINE case below runs. 2541884a6e5dSDave Hansen */ 2542884a6e5dSDave Hansen disable_all_migrate_targets(); 2543884a6e5dSDave Hansen break; 2544884a6e5dSDave Hansen case MEM_OFFLINE: 2545884a6e5dSDave Hansen case MEM_ONLINE: 2546884a6e5dSDave Hansen /* 2547884a6e5dSDave Hansen * Recalculate the target nodes once the node 2548884a6e5dSDave Hansen * reaches its final state (online or offline). 2549884a6e5dSDave Hansen */ 2550884a6e5dSDave Hansen __set_migration_target_nodes(); 2551884a6e5dSDave Hansen break; 2552884a6e5dSDave Hansen case MEM_CANCEL_OFFLINE: 2553884a6e5dSDave Hansen /* 2554884a6e5dSDave Hansen * MEM_GOING_OFFLINE disabled all the migration 2555884a6e5dSDave Hansen * targets. Reenable them. 2556884a6e5dSDave Hansen */ 2557884a6e5dSDave Hansen __set_migration_target_nodes(); 2558884a6e5dSDave Hansen break; 2559884a6e5dSDave Hansen case MEM_GOING_ONLINE: 2560884a6e5dSDave Hansen case MEM_CANCEL_ONLINE: 2561884a6e5dSDave Hansen break; 2562884a6e5dSDave Hansen } 2563884a6e5dSDave Hansen 2564884a6e5dSDave Hansen return notifier_from_errno(0); 2565884a6e5dSDave Hansen } 25667d6e2d96SOscar Salvador #endif 2567884a6e5dSDave Hansen 2568734c1570SOscar Salvador void __init migrate_on_reclaim_init(void) 256976af6a05SDave Hansen { 25703f26c88bSMiaohe Lin node_demotion = kcalloc(nr_node_ids, 2571ac16ec83SBaolin Wang sizeof(struct demotion_nodes), 2572ac16ec83SBaolin Wang GFP_KERNEL); 2573ac16ec83SBaolin Wang WARN_ON(!node_demotion); 25747d6e2d96SOscar Salvador #ifdef CONFIG_MEMORY_HOTPLUG 2575884a6e5dSDave Hansen hotplug_memory_notifier(migrate_on_reclaim_callback, 100); 25767d6e2d96SOscar Salvador #endif 2577734c1570SOscar Salvador /* 2578734c1570SOscar Salvador * At this point, all numa nodes with memory/CPus have their state 2579734c1570SOscar Salvador * properly set, so we can build the demotion order now. 2580734c1570SOscar Salvador * Let us hold the cpu_hotplug lock just, as we could possibily have 2581734c1570SOscar Salvador * CPU hotplug events during boot. 2582734c1570SOscar Salvador */ 2583734c1570SOscar Salvador cpus_read_lock(); 2584734c1570SOscar Salvador set_migration_target_nodes(); 2585734c1570SOscar Salvador cpus_read_unlock(); 2586884a6e5dSDave Hansen } 258720f9ba4fSYang Shi 258820f9ba4fSYang Shi bool numa_demotion_enabled = false; 258920f9ba4fSYang Shi 259020f9ba4fSYang Shi #ifdef CONFIG_SYSFS 259120f9ba4fSYang Shi static ssize_t numa_demotion_enabled_show(struct kobject *kobj, 259220f9ba4fSYang Shi struct kobj_attribute *attr, char *buf) 259320f9ba4fSYang Shi { 259420f9ba4fSYang Shi return sysfs_emit(buf, "%s\n", 259520f9ba4fSYang Shi numa_demotion_enabled ? "true" : "false"); 259620f9ba4fSYang Shi } 259720f9ba4fSYang Shi 259820f9ba4fSYang Shi static ssize_t numa_demotion_enabled_store(struct kobject *kobj, 259920f9ba4fSYang Shi struct kobj_attribute *attr, 260020f9ba4fSYang Shi const char *buf, size_t count) 260120f9ba4fSYang Shi { 2602717aeab4SJagdish Gediya ssize_t ret; 2603717aeab4SJagdish Gediya 2604717aeab4SJagdish Gediya ret = kstrtobool(buf, &numa_demotion_enabled); 2605717aeab4SJagdish Gediya if (ret) 2606717aeab4SJagdish Gediya return ret; 260720f9ba4fSYang Shi 260820f9ba4fSYang Shi return count; 260920f9ba4fSYang Shi } 261020f9ba4fSYang Shi 261120f9ba4fSYang Shi static struct kobj_attribute numa_demotion_enabled_attr = 261220f9ba4fSYang Shi __ATTR(demotion_enabled, 0644, numa_demotion_enabled_show, 261320f9ba4fSYang Shi numa_demotion_enabled_store); 261420f9ba4fSYang Shi 261520f9ba4fSYang Shi static struct attribute *numa_attrs[] = { 261620f9ba4fSYang Shi &numa_demotion_enabled_attr.attr, 261720f9ba4fSYang Shi NULL, 261820f9ba4fSYang Shi }; 261920f9ba4fSYang Shi 262020f9ba4fSYang Shi static const struct attribute_group numa_attr_group = { 262120f9ba4fSYang Shi .attrs = numa_attrs, 262220f9ba4fSYang Shi }; 262320f9ba4fSYang Shi 262420f9ba4fSYang Shi static int __init numa_init_sysfs(void) 262520f9ba4fSYang Shi { 262620f9ba4fSYang Shi int err; 262720f9ba4fSYang Shi struct kobject *numa_kobj; 262820f9ba4fSYang Shi 262920f9ba4fSYang Shi numa_kobj = kobject_create_and_add("numa", mm_kobj); 263020f9ba4fSYang Shi if (!numa_kobj) { 263120f9ba4fSYang Shi pr_err("failed to create numa kobject\n"); 263220f9ba4fSYang Shi return -ENOMEM; 263320f9ba4fSYang Shi } 263420f9ba4fSYang Shi err = sysfs_create_group(numa_kobj, &numa_attr_group); 263520f9ba4fSYang Shi if (err) { 263620f9ba4fSYang Shi pr_err("failed to register numa group\n"); 263720f9ba4fSYang Shi goto delete_obj; 263820f9ba4fSYang Shi } 263920f9ba4fSYang Shi return 0; 264020f9ba4fSYang Shi 264120f9ba4fSYang Shi delete_obj: 264220f9ba4fSYang Shi kobject_put(numa_kobj); 264320f9ba4fSYang Shi return err; 264420f9ba4fSYang Shi } 264520f9ba4fSYang Shi subsys_initcall(numa_init_sysfs); 26467d6e2d96SOscar Salvador #endif /* CONFIG_SYSFS */ 26477d6e2d96SOscar Salvador #endif /* CONFIG_NUMA */ 2648