diff options
| -rw-r--r-- | mm/slub.c | 59 |
1 files changed, 24 insertions, 35 deletions
diff --git a/mm/slub.c b/mm/slub.c index 175cd905b58a..13e5821ce3e2 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2167,9 +2167,9 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page, { enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE }; struct kmem_cache_node *n = get_node(s, page_to_nid(page)); - int lock = 0; + int lock = 0, free_delta = 0; enum slab_modes l = M_NONE, m = M_NONE; - void *nextfree; + void *nextfree, *freelist_iter, *freelist_tail; int tail = DEACTIVATE_TO_HEAD; struct page new; struct page old; @@ -2180,45 +2180,34 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page, } /* - * Stage one: Free all available per cpu objects back - * to the page freelist while it is still frozen. Leave the - * last one. - * - * There is no need to take the list->lock because the page - * is still frozen. + * Stage one: Count the objects on cpu's freelist as free_delta and + * remember the last object in freelist_tail for later splicing. */ - while (freelist && (nextfree = get_freepointer(s, freelist))) { - void *prior; - unsigned long counters; + freelist_tail = NULL; + freelist_iter = freelist; + while (freelist_iter) { + nextfree = get_freepointer(s, freelist_iter); /* * If 'nextfree' is invalid, it is possible that the object at - * 'freelist' is already corrupted. So isolate all objects - * starting at 'freelist'. + * 'freelist_iter' is already corrupted. So isolate all objects + * starting at 'freelist_iter' by skipping them. */ - if (freelist_corrupted(s, page, &freelist, nextfree)) + if (freelist_corrupted(s, page, &freelist_iter, nextfree)) break; - do { - prior = page->freelist; - counters = page->counters; - set_freepointer(s, freelist, prior); - new.counters = counters; - new.inuse--; - VM_BUG_ON(!new.frozen); + freelist_tail = freelist_iter; + free_delta++; - } while (!__cmpxchg_double_slab(s, page, - prior, counters, - freelist, new.counters, - "drain percpu freelist")); - - freelist = nextfree; + freelist_iter = nextfree; } /* - * Stage two: Ensure that the page is unfrozen while the - * list presence reflects the actual number of objects - * during unfreeze. + * Stage two: Unfreeze the page while splicing the per-cpu + * freelist to the head of page's freelist. + * + * Ensure that the page is unfrozen while the list presence + * reflects the actual number of objects during unfreeze. * * We setup the list membership and then perform a cmpxchg * with the count. If there is a mismatch then the page @@ -2231,15 +2220,15 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page, */ redo: - old.freelist = page->freelist; - old.counters = page->counters; + old.freelist = READ_ONCE(page->freelist); + old.counters = READ_ONCE(page->counters); VM_BUG_ON(!old.frozen); /* Determine target state of the slab */ new.counters = old.counters; - if (freelist) { - new.inuse--; - set_freepointer(s, freelist, old.freelist); + if (freelist_tail) { + new.inuse -= free_delta; + set_freepointer(s, freelist_tail, old.freelist); new.freelist = freelist; } else new.freelist = old.freelist; |