diff options
| -rw-r--r-- | mm/huge_memory.c | 28 | ||||
| -rw-r--r-- | mm/migrate.c | 95 |
2 files changed, 52 insertions, 71 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9db521fa8e8..f40b2ce23d6 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1296,7 +1296,6 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, int target_nid; int current_nid = -1; bool migrated; - bool page_locked = false; spin_lock(&mm->page_table_lock); if (unlikely(!pmd_same(pmd, *pmdp))) @@ -1318,7 +1317,6 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, /* Acquire the page lock to serialise THP migrations */ spin_unlock(&mm->page_table_lock); lock_page(page); - page_locked = true; /* Confirm the PTE did not while locked */ spin_lock(&mm->page_table_lock); @@ -1331,34 +1329,26 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, /* Migrate the THP to the requested node */ migrated = migrate_misplaced_transhuge_page(mm, vma, - pmdp, pmd, addr, - page, target_nid); - if (migrated) - current_nid = target_nid; - else { - spin_lock(&mm->page_table_lock); - if (unlikely(!pmd_same(pmd, *pmdp))) { - unlock_page(page); - goto out_unlock; - } - goto clear_pmdnuma; - } + pmdp, pmd, addr, page, target_nid); + if (!migrated) + goto check_same; - task_numa_fault(current_nid, HPAGE_PMD_NR, migrated); + task_numa_fault(target_nid, HPAGE_PMD_NR, true); return 0; +check_same: + spin_lock(&mm->page_table_lock); + if (unlikely(!pmd_same(pmd, *pmdp))) + goto out_unlock; clear_pmdnuma: pmd = pmd_mknonnuma(pmd); set_pmd_at(mm, haddr, pmdp, pmd); VM_BUG_ON(pmd_numa(*pmdp)); update_mmu_cache_pmd(vma, addr, pmdp); - if (page_locked) - unlock_page(page); - out_unlock: spin_unlock(&mm->page_table_lock); if (current_nid != -1) - task_numa_fault(current_nid, HPAGE_PMD_NR, migrated); + task_numa_fault(current_nid, HPAGE_PMD_NR, false); return 0; } diff --git a/mm/migrate.c b/mm/migrate.c index 77f4e70df24..f560071e89c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1557,41 +1557,40 @@ bool numamigrate_update_ratelimit(pg_data_t *pgdat, unsigned long nr_pages) int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) { - int ret = 0; + int page_lru; VM_BUG_ON(compound_order(page) && !PageTransHuge(page)); /* Avoid migrating to a node that is nearly full */ - if (migrate_balanced_pgdat(pgdat, 1UL << compound_order(page))) { - int page_lru; + if (!migrate_balanced_pgdat(pgdat, 1UL << compound_order(page))) + return 0; - if (isolate_lru_page(page)) { - put_page(page); - return 0; - } + if (isolate_lru_page(page)) + return 0; - /* Page is isolated */ - ret = 1; - page_lru = page_is_file_cache(page); - if (!PageTransHuge(page)) - inc_zone_page_state(page, NR_ISOLATED_ANON + page_lru); - else - mod_zone_page_state(page_zone(page), - NR_ISOLATED_ANON + page_lru, - HPAGE_PMD_NR); + /* + * migrate_misplaced_transhuge_page() skips page migration's usual + * check on page_count(), so we must do it here, now that the page + * has been isolated: a GUP pin, or any other pin, prevents migration. + * The expected page count is 3: 1 for page's mapcount and 1 for the + * caller's pin and 1 for the reference taken by isolate_lru_page(). + */ + if (PageTransHuge(page) && page_count(page) != 3) { + putback_lru_page(page); + return 0; } + page_lru = page_is_file_cache(page); + mod_zone_page_state(page_zone(page), NR_ISOLATED_ANON + page_lru, + hpage_nr_pages(page)); + /* - * Page is either isolated or there is not enough space on the target - * node. If isolated, then it has taken a reference count and the - * callers reference can be safely dropped without the page - * disappearing underneath us during migration. Otherwise the page is - * not to be migrated but the callers reference should still be - * dropped so it does not leak. + * Isolating the page has taken another reference, so the + * caller's reference can be safely dropped without the page + * disappearing underneath us during migration. */ put_page(page); - - return ret; + return 1; } /* @@ -1602,7 +1601,7 @@ int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) int migrate_misplaced_page(struct page *page, int node) { pg_data_t *pgdat = NODE_DATA(node); - int isolated = 0; + int isolated; int nr_remaining; LIST_HEAD(migratepages); @@ -1610,20 +1609,16 @@ int migrate_misplaced_page(struct page *page, int node) * Don't migrate pages that are mapped in multiple processes. * TODO: Handle false sharing detection instead of this hammer */ - if (page_mapcount(page) != 1) { - put_page(page); + if (page_mapcount(page) != 1) goto out; - } /* * Rate-limit the amount of data that is being migrated to a node. * Optimal placement is no good if the memory bus is saturated and * all the time is being spent migrating! */ - if (numamigrate_update_ratelimit(pgdat, 1)) { - put_page(page); + if (numamigrate_update_ratelimit(pgdat, 1)) goto out; - } isolated = numamigrate_isolate_page(pgdat, page); if (!isolated) @@ -1640,12 +1635,19 @@ int migrate_misplaced_page(struct page *page, int node) } else count_vm_numa_event(NUMA_PAGE_MIGRATE); BUG_ON(!list_empty(&migratepages)); -out: return isolated; + +out: + put_page(page); + return 0; } #endif /* CONFIG_NUMA_BALANCING */ #if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE) +/* + * Migrates a THP to a given target node. page must be locked and is unlocked + * before returning. + */ int migrate_misplaced_transhuge_page(struct mm_struct *mm, struct vm_area_struct *vma, pmd_t *pmd, pmd_t entry, @@ -1676,29 +1678,15 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, new_page = alloc_pages_node(node, (GFP_TRANSHUGE | GFP_THISNODE) & ~__GFP_WAIT, HPAGE_PMD_ORDER); - if (!new_page) { - count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR); - goto out_dropref; - } + if (!new_page) + goto out_fail; + page_xchg_last_nid(new_page, page_last_nid(page)); isolated = numamigrate_isolate_page(pgdat, page); - - /* - * Failing to isolate or a GUP pin prevents migration. The expected - * page count is 2. 1 for anonymous pages without a mapping and 1 - * for the callers pin. If the page was isolated, the page will - * need to be put back on the LRU. - */ - if (!isolated || page_count(page) != 2) { - count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR); + if (!isolated) { put_page(new_page); - if (isolated) { - putback_lru_page(page); - isolated = 0; - goto out; - } - goto out_keep_locked; + goto out_fail; } /* Prepare a page as a migration target */ @@ -1730,6 +1718,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, putback_lru_page(page); count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR); + isolated = 0; goto out; } @@ -1774,9 +1763,11 @@ out: -HPAGE_PMD_NR); return isolated; +out_fail: + count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR); out_dropref: + unlock_page(page); put_page(page); -out_keep_locked: return 0; } #endif /* CONFIG_NUMA_BALANCING */ |