diff options
author | Christoph Hellwig <hch@lst.de> | 2022-02-16 15:31:38 +1100 |
---|---|---|
committer | Matthew Wilcox (Oracle) <willy@infradead.org> | 2022-03-03 12:47:33 -0500 |
commit | 76cbbead253ddcae9878be0d702208bb1e4fac6f (patch) | |
tree | b524f64471425baf4acf142d4c4497c9e58a5122 /mm/migrate.c | |
parent | aaf7d70cc595c78d27e915451e93a4459cfc36f3 (diff) | |
download | linux-76cbbead253ddcae9878be0d702208bb1e4fac6f.tar.gz linux-76cbbead253ddcae9878be0d702208bb1e4fac6f.tar.bz2 linux-76cbbead253ddcae9878be0d702208bb1e4fac6f.zip |
mm: move the migrate_vma_* device migration code into its own file
Split the code used to migrate to and from ZONE_DEVICE memory from
migrate.c into a new file.
Link: https://lkml.kernel.org/r/20220210072828.2930359-14-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: "Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Knig <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Diffstat (limited to 'mm/migrate.c')
-rw-r--r-- | mm/migrate.c | 753 |
1 files changed, 0 insertions, 753 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 7dffd5f82a60..f4076093c855 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -38,12 +38,10 @@ #include <linux/hugetlb.h> #include <linux/hugetlb_cgroup.h> #include <linux/gfp.h> -#include <linux/pagewalk.h> #include <linux/pfn_t.h> #include <linux/memremap.h> #include <linux/userfaultfd_k.h> #include <linux/balloon_compaction.h> -#include <linux/mmu_notifier.h> #include <linux/page_idle.h> #include <linux/page_owner.h> #include <linux/sched/mm.h> @@ -2129,757 +2127,6 @@ out: #endif /* CONFIG_NUMA_BALANCING */ #endif /* CONFIG_NUMA */ -#ifdef CONFIG_DEVICE_PRIVATE -static int migrate_vma_collect_skip(unsigned long start, - unsigned long end, - struct mm_walk *walk) -{ - struct migrate_vma *migrate = walk->private; - unsigned long addr; - - for (addr = start; addr < end; addr += PAGE_SIZE) { - migrate->dst[migrate->npages] = 0; - migrate->src[migrate->npages++] = 0; - } - - return 0; -} - -static int migrate_vma_collect_hole(unsigned long start, - unsigned long end, - __always_unused int depth, - struct mm_walk *walk) -{ - struct migrate_vma *migrate = walk->private; - unsigned long addr; - - /* Only allow populating anonymous memory. */ - if (!vma_is_anonymous(walk->vma)) - return migrate_vma_collect_skip(start, end, walk); - - for (addr = start; addr < end; addr += PAGE_SIZE) { - migrate->src[migrate->npages] = MIGRATE_PFN_MIGRATE; - migrate->dst[migrate->npages] = 0; - migrate->npages++; - migrate->cpages++; - } - - return 0; -} - -static int migrate_vma_collect_pmd(pmd_t *pmdp, - unsigned long start, - unsigned long end, - struct mm_walk *walk) -{ - struct migrate_vma *migrate = walk->private; - struct vm_area_struct *vma = walk->vma; - struct mm_struct *mm = vma->vm_mm; - unsigned long addr = start, unmapped = 0; - spinlock_t *ptl; - pte_t *ptep; - -again: - if (pmd_none(*pmdp)) - return migrate_vma_collect_hole(start, end, -1, walk); - - if (pmd_trans_huge(*pmdp)) { - struct page *page; - - ptl = pmd_lock(mm, pmdp); - if (unlikely(!pmd_trans_huge(*pmdp))) { - spin_unlock(ptl); - goto again; - } - - page = pmd_page(*pmdp); - if (is_huge_zero_page(page)) { - spin_unlock(ptl); - split_huge_pmd(vma, pmdp, addr); - if (pmd_trans_unstable(pmdp)) - return migrate_vma_collect_skip(start, end, - walk); - } else { - int ret; - - get_page(page); - spin_unlock(ptl); - if (unlikely(!trylock_page(page))) - return migrate_vma_collect_skip(start, end, - walk); - ret = split_huge_page(page); - unlock_page(page); - put_page(page); - if (ret) - return migrate_vma_collect_skip(start, end, - walk); - if (pmd_none(*pmdp)) - return migrate_vma_collect_hole(start, end, -1, - walk); - } - } - - if (unlikely(pmd_bad(*pmdp))) - return migrate_vma_collect_skip(start, end, walk); - - ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl); - arch_enter_lazy_mmu_mode(); - - for (; addr < end; addr += PAGE_SIZE, ptep++) { - unsigned long mpfn = 0, pfn; - struct page *page; - swp_entry_t entry; - pte_t pte; - - pte = *ptep; - - if (pte_none(pte)) { - if (vma_is_anonymous(vma)) { - mpfn = MIGRATE_PFN_MIGRATE; - migrate->cpages++; - } - goto next; - } - - if (!pte_present(pte)) { - /* - * Only care about unaddressable device page special - * page table entry. Other special swap entries are not - * migratable, and we ignore regular swapped page. - */ - entry = pte_to_swp_entry(pte); - if (!is_device_private_entry(entry)) - goto next; - - page = pfn_swap_entry_to_page(entry); - if (!(migrate->flags & - MIGRATE_VMA_SELECT_DEVICE_PRIVATE) || - page->pgmap->owner != migrate->pgmap_owner) - goto next; - - mpfn = migrate_pfn(page_to_pfn(page)) | - MIGRATE_PFN_MIGRATE; - if (is_writable_device_private_entry(entry)) - mpfn |= MIGRATE_PFN_WRITE; - } else { - if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM)) - goto next; - pfn = pte_pfn(pte); - if (is_zero_pfn(pfn)) { - mpfn = MIGRATE_PFN_MIGRATE; - migrate->cpages++; - goto next; - } - page = vm_normal_page(migrate->vma, addr, pte); - mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE; - mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0; - } - - /* FIXME support THP */ - if (!page || !page->mapping || PageTransCompound(page)) { - mpfn = 0; - goto next; - } - - /* - * By getting a reference on the page we pin it and that blocks - * any kind of migration. Side effect is that it "freezes" the - * pte. - * - * We drop this reference after isolating the page from the lru - * for non device page (device page are not on the lru and thus - * can't be dropped from it). - */ - get_page(page); - - /* - * Optimize for the common case where page is only mapped once - * in one process. If we can lock the page, then we can safely - * set up a special migration page table entry now. - */ - if (trylock_page(page)) { - pte_t swp_pte; - - migrate->cpages++; - ptep_get_and_clear(mm, addr, ptep); - - /* Setup special migration page table entry */ - if (mpfn & MIGRATE_PFN_WRITE) - entry = make_writable_migration_entry( - page_to_pfn(page)); - else - entry = make_readable_migration_entry( - page_to_pfn(page)); - swp_pte = swp_entry_to_pte(entry); - if (pte_present(pte)) { - if (pte_soft_dirty(pte)) - swp_pte = pte_swp_mksoft_dirty(swp_pte); - if (pte_uffd_wp(pte)) - swp_pte = pte_swp_mkuffd_wp(swp_pte); - } else { - if (pte_swp_soft_dirty(pte)) - swp_pte = pte_swp_mksoft_dirty(swp_pte); - if (pte_swp_uffd_wp(pte)) - swp_pte = pte_swp_mkuffd_wp(swp_pte); - } - set_pte_at(mm, addr, ptep, swp_pte); - - /* - * This is like regular unmap: we remove the rmap and - * drop page refcount. Page won't be freed, as we took - * a reference just above. - */ - page_remove_rmap(page, vma, false); - put_page(page); - - if (pte_present(pte)) - unmapped++; - } else { - put_page(page); - mpfn = 0; - } - -next: - migrate->dst[migrate->npages] = 0; - migrate->src[migrate->npages++] = mpfn; - } - arch_leave_lazy_mmu_mode(); - pte_unmap_unlock(ptep - 1, ptl); - - /* Only flush the TLB if we actually modified any entries */ - if (unmapped) - flush_tlb_range(walk->vma, start, end); - - return 0; -} - -static const struct mm_walk_ops migrate_vma_walk_ops = { - .pmd_entry = migrate_vma_collect_pmd, - .pte_hole = migrate_vma_collect_hole, -}; - -/* - * migrate_vma_collect() - collect pages over a range of virtual addresses - * @migrate: migrate struct containing all migration information - * - * This will walk the CPU page table. For each virtual address backed by a - * valid page, it updates the src array and takes a reference on the page, in - * order to pin the page until we lock it and unmap it. - */ -static void migrate_vma_collect(struct migrate_vma *migrate) -{ - struct mmu_notifier_range range; - - /* - * Note that the pgmap_owner is passed to the mmu notifier callback so - * that the registered device driver can skip invalidating device - * private page mappings that won't be migrated. - */ - mmu_notifier_range_init_owner(&range, MMU_NOTIFY_MIGRATE, 0, - migrate->vma, migrate->vma->vm_mm, migrate->start, migrate->end, - migrate->pgmap_owner); - mmu_notifier_invalidate_range_start(&range); - - walk_page_range(migrate->vma->vm_mm, migrate->start, migrate->end, - &migrate_vma_walk_ops, migrate); - - mmu_notifier_invalidate_range_end(&range); - migrate->end = migrate->start + (migrate->npages << PAGE_SHIFT); -} - -/* - * migrate_vma_check_page() - check if page is pinned or not - * @page: struct page to check - * - * Pinned pages cannot be migrated. This is the same test as in - * folio_migrate_mapping(), except that here we allow migration of a - * ZONE_DEVICE page. - */ -static bool migrate_vma_check_page(struct page *page) -{ - /* - * One extra ref because caller holds an extra reference, either from - * isolate_lru_page() for a regular page, or migrate_vma_collect() for - * a device page. - */ - int extra = 1; - - /* - * FIXME support THP (transparent huge page), it is bit more complex to - * check them than regular pages, because they can be mapped with a pmd - * or with a pte (split pte mapping). - */ - if (PageCompound(page)) - return false; - - /* Page from ZONE_DEVICE have one extra reference */ - if (is_zone_device_page(page)) - extra++; - - /* For file back page */ - if (page_mapping(page)) - extra += 1 + page_has_private(page); - - if ((page_count(page) - extra) > page_mapcount(page)) - return false; - - return true; -} - -/* - * migrate_vma_unmap() - replace page mapping with special migration pte entry - * @migrate: migrate struct containing all migration information - * - * Isolate pages from the LRU and replace mappings (CPU page table pte) with a - * special migration pte entry and check if it has been pinned. Pinned pages are - * restored because we cannot migrate them. - * - * This is the last step before we call the device driver callback to allocate - * destination memory and copy contents of original page over to new page. - */ -static void migrate_vma_unmap(struct migrate_vma *migrate) -{ - const unsigned long npages = migrate->npages; - unsigned long i, restore = 0; - bool allow_drain = true; - - lru_add_drain(); - - for (i = 0; i < npages; i++) { - struct page *page = migrate_pfn_to_page(migrate->src[i]); - - if (!page) - continue; - - /* ZONE_DEVICE pages are not on LRU */ - if (!is_zone_device_page(page)) { - if (!PageLRU(page) && allow_drain) { - /* Drain CPU's pagevec */ - lru_add_drain_all(); - allow_drain = false; - } - - if (isolate_lru_page(page)) { - migrate->src[i] &= ~MIGRATE_PFN_MIGRATE; - migrate->cpages--; - restore++; - continue; - } - - /* Drop the reference we took in collect */ - put_page(page); - } - - if (page_mapped(page)) - try_to_migrate(page, 0); - - if (page_mapped(page) || !migrate_vma_check_page(page)) { - if (!is_zone_device_page(page)) { - get_page(page); - putback_lru_page(page); - } - - migrate->src[i] &= ~MIGRATE_PFN_MIGRATE; - migrate->cpages--; - restore++; - continue; - } - } - - for (i = 0; i < npages && restore; i++) { - struct page *page = migrate_pfn_to_page(migrate->src[i]); - - if (!page || (migrate->src[i] & MIGRATE_PFN_MIGRATE)) - continue; - - remove_migration_ptes(page, page, false); - - migrate->src[i] = 0; - unlock_page(page); - put_page(page); - restore--; - } -} - -/** - * migrate_vma_setup() - prepare to migrate a range of memory - * @args: contains the vma, start, and pfns arrays for the migration - * - * Returns: negative errno on failures, 0 when 0 or more pages were migrated - * without an error. - * - * Prepare to migrate a range of memory virtual address range by collecting all - * the pages backing each virtual address in the range, saving them inside the - * src array. Then lock those pages and unmap them. Once the pages are locked - * and unmapped, check whether each page is pinned or not. Pages that aren't - * pinned have the MIGRATE_PFN_MIGRATE flag set (by this function) in the - * corresponding src array entry. Then restores any pages that are pinned, by - * remapping and unlocking those pages. - * - * The caller should then allocate destination memory and copy source memory to - * it for all those entries (ie with MIGRATE_PFN_VALID and MIGRATE_PFN_MIGRATE - * flag set). Once these are allocated and copied, the caller must update each - * corresponding entry in the dst array with the pfn value of the destination - * page and with MIGRATE_PFN_VALID. Destination pages must be locked via - * lock_page(). - * - * Note that the caller does not have to migrate all the pages that are marked - * with MIGRATE_PFN_MIGRATE flag in src array unless this is a migration from - * device memory to system memory. If the caller cannot migrate a device page - * back to system memory, then it must return VM_FAULT_SIGBUS, which has severe - * consequences for the userspace process, so it must be avoided if at all - * possible. - * - * For empty entries inside CPU page table (pte_none() or pmd_none() is true) we - * do set MIGRATE_PFN_MIGRATE flag inside the corresponding source array thus - * allowing the caller to allocate device memory for those unbacked virtual - * addresses. For this the caller simply has to allocate device memory and - * properly set the destination entry like for regular migration. Note that - * this can still fail, and thus inside the device driver you must check if the - * migration was successful for those entries after calling migrate_vma_pages(), - * just like for regular migration. - * - * After that, the callers must call migrate_vma_pages() to go over each entry - * in the src array that has the MIGRATE_PFN_VALID and MIGRATE_PFN_MIGRATE flag - * set. If the corresponding entry in dst array has MIGRATE_PFN_VALID flag set, - * then migrate_vma_pages() to migrate struct page information from the source - * struct page to the destination struct page. If it fails to migrate the - * struct page information, then it clears the MIGRATE_PFN_MIGRATE flag in the - * src array. - * - * At this point all successfully migrated pages have an entry in the src - * array with MIGRATE_PFN_VALID and MIGRATE_PFN_MIGRATE flag set and the dst - * array entry with MIGRATE_PFN_VALID flag set. - * - * Once migrate_vma_pages() returns the caller may inspect which pages were - * successfully migrated, and which were not. Successfully migrated pages will - * have the MIGRATE_PFN_MIGRATE flag set for their src array entry. - * - * It is safe to update device page table after migrate_vma_pages() because - * both destination and source page are still locked, and the mmap_lock is held - * in read mode (hence no one can unmap the range being migrated). - * - * Once the caller is done cleaning up things and updating its page table (if it - * chose to do so, this is not an obligation) it finally calls - * migrate_vma_finalize() to update the CPU page table to point to new pages - * for successfully migrated pages or otherwise restore the CPU page table to - * point to the original source pages. - */ -int migrate_vma_setup(struct migrate_vma *args) -{ - long nr_pages = (args->end - args->start) >> PAGE_SHIFT; - - args->start &= PAGE_MASK; - args->end &= PAGE_MASK; - if (!args->vma || is_vm_hugetlb_page(args->vma) || - (args->vma->vm_flags & VM_SPECIAL) || vma_is_dax(args->vma)) - return -EINVAL; - if (nr_pages <= 0) - return -EINVAL; - if (args->start < args->vma->vm_start || - args->start >= args->vma->vm_end) - return -EINVAL; - if (args->end <= args->vma->vm_start || args->end > args->vma->vm_end) - return -EINVAL; - if (!args->src || !args->dst) - return -EINVAL; - - memset(args->src, 0, sizeof(*args->src) * nr_pages); - args->cpages = 0; - args->npages = 0; - - migrate_vma_collect(args); - - if (args->cpages) - migrate_vma_unmap(args); - - /* - * At this point pages are locked and unmapped, and thus they have - * stable content and can safely be copied to destination memory that - * is allocated by the drivers. - */ - return 0; - -} -EXPORT_SYMBOL(migrate_vma_setup); - -/* - * This code closely matches the code in: - * __handle_mm_fault() - * handle_pte_fault() - * do_anonymous_page() - * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE - * private page. - */ -static void migrate_vma_insert_page(struct migrate_vma *migrate, - unsigned long addr, - struct page *page, - unsigned long *src) -{ - struct vm_area_struct *vma = migrate->vma; - struct mm_struct *mm = vma->vm_mm; - bool flush = false; - spinlock_t *ptl; - pte_t entry; - pgd_t *pgdp; - p4d_t *p4dp; - pud_t *pudp; - pmd_t *pmdp; - pte_t *ptep; - - /* Only allow populating anonymous memory */ - if (!vma_is_anonymous(vma)) - goto abort; - - pgdp = pgd_offset(mm, addr); - p4dp = p4d_alloc(mm, pgdp, addr); - if (!p4dp) - goto abort; - pudp = pud_alloc(mm, p4dp, addr); - if (!pudp) - goto abort; - pmdp = pmd_alloc(mm, pudp, addr); - if (!pmdp) - goto abort; - - if (pmd_trans_huge(*pmdp) || pmd_devmap(*pmdp)) - goto abort; - - /* - * Use pte_alloc() instead of pte_alloc_map(). We can't run - * pte_offset_map() on pmds where a huge pmd might be created - * from a different thread. - * - * pte_alloc_map() is safe to use under mmap_write_lock(mm) or when - * parallel threads are excluded by other means. - * - * Here we only have mmap_read_lock(mm). - */ - if (pte_alloc(mm, pmdp)) - goto abort; - - /* See the comment in pte_alloc_one_map() */ - if (unlikely(pmd_trans_unstable(pmdp))) - goto abort; - - if (unlikely(anon_vma_prepare(vma))) - goto abort; - if (mem_cgroup_charge(page_folio(page), vma->vm_mm, GFP_KERNEL)) - goto abort; - - /* - * The memory barrier inside __SetPageUptodate makes sure that - * preceding stores to the page contents become visible before - * the set_pte_at() write. - */ - __SetPageUptodate(page); - - if (is_device_private_page(page)) { - swp_entry_t swp_entry; - - if (vma->vm_flags & VM_WRITE) - swp_entry = make_writable_device_private_entry( - page_to_pfn(page)); - else - swp_entry = make_readable_device_private_entry( - page_to_pfn(page)); - entry = swp_entry_to_pte(swp_entry); - } else { - /* - * For now we only support migrating to un-addressable device - * memory. - */ - if (is_zone_device_page(page)) { - pr_warn_once("Unsupported ZONE_DEVICE page type.\n"); - goto abort; - } - entry = mk_pte(page, vma->vm_page_prot); - if (vma->vm_flags & VM_WRITE) - entry = pte_mkwrite(pte_mkdirty(entry)); - } - - ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl); - - if (check_stable_address_space(mm)) - goto unlock_abort; - - if (pte_present(*ptep)) { - unsigned long pfn = pte_pfn(*ptep); - - if (!is_zero_pfn(pfn)) - goto unlock_abort; - flush = true; - } else if (!pte_none(*ptep)) - goto unlock_abort; - - /* - * Check for userfaultfd but do not deliver the fault. Instead, - * just back off. - */ - if (userfaultfd_missing(vma)) - goto unlock_abort; - - inc_mm_counter(mm, MM_ANONPAGES); - page_add_new_anon_rmap(page, vma, addr, false); - if (!is_zone_device_page(page)) - lru_cache_add_inactive_or_unevictable(page, vma); - get_page(page); - - if (flush) { - flush_cache_page(vma, addr, pte_pfn(*ptep)); - ptep_clear_flush_notify(vma, addr, ptep); - set_pte_at_notify(mm, addr, ptep, entry); - update_mmu_cache(vma, addr, ptep); - } else { - /* No need to invalidate - it was non-present before */ - set_pte_at(mm, addr, ptep, entry); - update_mmu_cache(vma, addr, ptep); - } - - pte_unmap_unlock(ptep, ptl); - *src = MIGRATE_PFN_MIGRATE; - return; - -unlock_abort: - pte_unmap_unlock(ptep, ptl); -abort: - *src &= ~MIGRATE_PFN_MIGRATE; -} - -/** - * migrate_vma_pages() - migrate meta-data from src page to dst page - * @migrate: migrate struct containing all migration information - * - * This migrates struct page meta-data from source struct page to destination - * struct page. This effectively finishes the migration from source page to the - * destination page. - */ -void migrate_vma_pages(struct migrate_vma *migrate) -{ - const unsigned long npages = migrate->npages; - const unsigned long start = migrate->start; - struct mmu_notifier_range range; - unsigned long addr, i; - bool notified = false; - - for (i = 0, addr = start; i < npages; addr += PAGE_SIZE, i++) { - struct page *newpage = migrate_pfn_to_page(migrate->dst[i]); - struct page *page = migrate_pfn_to_page(migrate->src[i]); - struct address_space *mapping; - int r; - - if (!newpage) { - migrate->src[i] &= ~MIGRATE_PFN_MIGRATE; - continue; - } - - if (!page) { - if (!(migrate->src[i] & MIGRATE_PFN_MIGRATE)) - continue; - if (!notified) { - notified = true; - - mmu_notifier_range_init_owner(&range, - MMU_NOTIFY_MIGRATE, 0, migrate->vma, - migrate->vma->vm_mm, addr, migrate->end, - migrate->pgmap_owner); - mmu_notifier_invalidate_range_start(&range); - } - migrate_vma_insert_page(migrate, addr, newpage, - &migrate->src[i]); - continue; - } - - mapping = page_mapping(page); - - if (is_device_private_page(newpage)) { - /* - * For now only support private anonymous when migrating - * to un-addressable device memory. - */ - if (mapping) { - migrate->src[i] &= ~MIGRATE_PFN_MIGRATE; - continue; - } - } else if (is_zone_device_page(newpage)) { - /* - * Other types of ZONE_DEVICE page are not supported. - */ - migrate->src[i] &= ~MIGRATE_PFN_MIGRATE; - continue; - } - - r = migrate_page(mapping, newpage, page, MIGRATE_SYNC_NO_COPY); - if (r != MIGRATEPAGE_SUCCESS) - migrate->src[i] &= ~MIGRATE_PFN_MIGRATE; - } - - /* - * No need to double call mmu_notifier->invalidate_range() callback as - * the above ptep_clear_flush_notify() inside migrate_vma_insert_page() - * did already call it. - */ - if (notified) - mmu_notifier_invalidate_range_only_end(&range); -} -EXPORT_SYMBOL(migrate_vma_pages); - -/** - * migrate_vma_finalize() - restore CPU page table entry - * @migrate: migrate struct containing all migration information - * - * This replaces the special migration pte entry with either a mapping to the - * new page if migration was successful for that page, or to the original page - * otherwise. - * - * This also unlocks the pages and puts them back on the lru, or drops the extra - * refcount, for device pages. - */ -void migrate_vma_finalize(struct migrate_vma *migrate) -{ - const unsigned long npages = migrate->npages; - unsigned long i; - - for (i = 0; i < npages; i++) { - struct page *newpage = migrate_pfn_to_page(migrate->dst[i]); - struct page *page = migrate_pfn_to_page(migrate->src[i]); - - if (!page) { - if (newpage) { - unlock_page(newpage); - put_page(newpage); - } - continue; - } - - if (!(migrate->src[i] & MIGRATE_PFN_MIGRATE) || !newpage) { - if (newpage) { - unlock_page(newpage); - put_page(newpage); - } - newpage = page; - } - - remove_migration_ptes(page, newpage, false); - unlock_page(page); - - if (is_zone_device_page(page)) - put_page(page); - else - putback_lru_page(page); - - if (newpage != page) { - unlock_page(newpage); - if (is_zone_device_page(newpage)) - put_page(newpage); - else - putback_lru_page(newpage); - } - } -} -EXPORT_SYMBOL(migrate_vma_finalize); -#endif /* CONFIG_DEVICE_PRIVATE */ - /* * node_demotion[] example: * |