diff options
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 69 |
1 files changed, 58 insertions, 11 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index bb940045fe8..e9b71020133 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -36,6 +36,7 @@ #include <linux/hugetlb_cgroup.h> #include <linux/gfp.h> #include <linux/balloon_compaction.h> +#include <linux/mmu_notifier.h> #include <asm/tlbflush.h> @@ -1654,6 +1655,18 @@ int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) return 1; } +bool pmd_trans_migrating(pmd_t pmd) +{ + struct page *page = pmd_page(pmd); + return PageLocked(page); +} + +void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd) +{ + struct page *page = pmd_page(*pmd); + wait_on_page_locked(page); +} + /* * Attempt to migrate a misplaced page to the specified destination * node. Caller is expected to have an elevated reference count on @@ -1716,12 +1729,14 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, struct page *page, int node) { spinlock_t *ptl; - unsigned long haddr = address & HPAGE_PMD_MASK; pg_data_t *pgdat = NODE_DATA(node); int isolated = 0; struct page *new_page = NULL; struct mem_cgroup *memcg = NULL; int page_lru = page_is_file_cache(page); + unsigned long mmun_start = address & HPAGE_PMD_MASK; + unsigned long mmun_end = mmun_start + HPAGE_PMD_SIZE; + pmd_t orig_entry; /* * Rate-limit the amount of data that is being migrated to a node. @@ -1744,6 +1759,9 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, goto out_fail; } + if (mm_tlb_flush_pending(mm)) + flush_tlb_range(vma, mmun_start, mmun_end); + /* Prepare a page as a migration target */ __set_page_locked(new_page); SetPageSwapBacked(new_page); @@ -1755,9 +1773,12 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, WARN_ON(PageLRU(new_page)); /* Recheck the target PMD */ + mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); ptl = pmd_lock(mm, pmd); - if (unlikely(!pmd_same(*pmd, entry))) { + if (unlikely(!pmd_same(*pmd, entry) || page_count(page) != 2)) { +fail_putback: spin_unlock(ptl); + mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); /* Reverse changes made by migrate_page_copy() */ if (TestClearPageActive(new_page)) @@ -1774,7 +1795,8 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, putback_lru_page(page); mod_zone_page_state(page_zone(page), NR_ISOLATED_ANON + page_lru, -HPAGE_PMD_NR); - goto out_fail; + + goto out_unlock; } /* @@ -1786,16 +1808,35 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, */ mem_cgroup_prepare_migration(page, new_page, &memcg); + orig_entry = *pmd; entry = mk_pmd(new_page, vma->vm_page_prot); - entry = pmd_mknonnuma(entry); - entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); entry = pmd_mkhuge(entry); + entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); - pmdp_clear_flush(vma, haddr, pmd); - set_pmd_at(mm, haddr, pmd, entry); - page_add_new_anon_rmap(new_page, vma, haddr); + /* + * Clear the old entry under pagetable lock and establish the new PTE. + * Any parallel GUP will either observe the old page blocking on the + * page lock, block on the page table lock or observe the new page. + * The SetPageUptodate on the new page and page_add_new_anon_rmap + * guarantee the copy is visible before the pagetable update. + */ + flush_cache_range(vma, mmun_start, mmun_end); + page_add_new_anon_rmap(new_page, vma, mmun_start); + pmdp_clear_flush(vma, mmun_start, pmd); + set_pmd_at(mm, mmun_start, pmd, entry); + flush_tlb_range(vma, mmun_start, mmun_end); update_mmu_cache_pmd(vma, address, &entry); + + if (page_count(page) != 2) { + set_pmd_at(mm, mmun_start, pmd, orig_entry); + flush_tlb_range(vma, mmun_start, mmun_end); + update_mmu_cache_pmd(vma, address, &entry); + page_remove_rmap(new_page); + goto fail_putback; + } + page_remove_rmap(page); + /* * Finish the charge transaction under the page table lock to * prevent split_huge_page() from dividing up the charge @@ -1803,6 +1844,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, */ mem_cgroup_end_migration(memcg, page, new_page, true); spin_unlock(ptl); + mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); unlock_page(new_page); unlock_page(page); @@ -1820,10 +1862,15 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, out_fail: count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR); out_dropref: - entry = pmd_mknonnuma(entry); - set_pmd_at(mm, haddr, pmd, entry); - update_mmu_cache_pmd(vma, address, &entry); + ptl = pmd_lock(mm, pmd); + if (pmd_same(*pmd, entry)) { + entry = pmd_mknonnuma(entry); + set_pmd_at(mm, mmun_start, pmd, entry); + update_mmu_cache_pmd(vma, address, &entry); + } + spin_unlock(ptl); +out_unlock: unlock_page(page); put_page(page); return 0; |