diff options
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r-- | mm/huge_memory.c | 70 |
1 files changed, 48 insertions, 22 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 610e3df..cca80d9 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1278,64 +1278,90 @@ out: int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, pmd_t pmd, pmd_t *pmdp) { + struct anon_vma *anon_vma = NULL; struct page *page; unsigned long haddr = addr & HPAGE_PMD_MASK; + int page_nid = -1, this_nid = numa_node_id(); int target_nid; - int current_nid = -1; - bool migrated; + bool page_locked; + bool migrated = false; spin_lock(&mm->page_table_lock); if (unlikely(!pmd_same(pmd, *pmdp))) goto out_unlock; page = pmd_page(pmd); - get_page(page); - current_nid = page_to_nid(page); + page_nid = page_to_nid(page); count_vm_numa_event(NUMA_HINT_FAULTS); - if (current_nid == numa_node_id()) + if (page_nid == this_nid) count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); + /* + * Acquire the page lock to serialise THP migrations but avoid dropping + * page_table_lock if at all possible + */ + page_locked = trylock_page(page); target_nid = mpol_misplaced(page, vma, haddr); if (target_nid == -1) { - put_page(page); - goto clear_pmdnuma; + /* If the page was locked, there are no parallel migrations */ + if (page_locked) + goto clear_pmdnuma; + + /* + * Otherwise wait for potential migrations and retry. We do + * relock and check_same as the page may no longer be mapped. + * As the fault is being retried, do not account for it. + */ + spin_unlock(&mm->page_table_lock); + wait_on_page_locked(page); + page_nid = -1; + goto out; } - /* Acquire the page lock to serialise THP migrations */ + /* Page is misplaced, serialise migrations and parallel THP splits */ + get_page(page); spin_unlock(&mm->page_table_lock); - lock_page(page); + if (!page_locked) + lock_page(page); + anon_vma = page_lock_anon_vma_read(page); /* Confirm the PTE did not while locked */ spin_lock(&mm->page_table_lock); if (unlikely(!pmd_same(pmd, *pmdp))) { unlock_page(page); put_page(page); + page_nid = -1; goto out_unlock; } - spin_unlock(&mm->page_table_lock); - /* Migrate the THP to the requested node */ + /* + * Migrate the THP to the requested node, returns with page unlocked + * and pmd_numa cleared. + */ + spin_unlock(&mm->page_table_lock); migrated = migrate_misplaced_transhuge_page(mm, vma, pmdp, pmd, addr, page, target_nid); - if (!migrated) - goto check_same; - - task_numa_fault(target_nid, HPAGE_PMD_NR, true); - return 0; + if (migrated) + page_nid = target_nid; -check_same: - spin_lock(&mm->page_table_lock); - if (unlikely(!pmd_same(pmd, *pmdp))) - goto out_unlock; + goto out; clear_pmdnuma: + BUG_ON(!PageLocked(page)); pmd = pmd_mknonnuma(pmd); set_pmd_at(mm, haddr, pmdp, pmd); VM_BUG_ON(pmd_numa(*pmdp)); update_mmu_cache_pmd(vma, addr, pmdp); + unlock_page(page); out_unlock: spin_unlock(&mm->page_table_lock); - if (current_nid != -1) - task_numa_fault(current_nid, HPAGE_PMD_NR, false); + +out: + if (anon_vma) + page_unlock_anon_vma_read(anon_vma); + + if (page_nid != -1) + task_numa_fault(page_nid, HPAGE_PMD_NR, migrated); + return 0; } |