From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f174.google.com (mail-io0-f174.google.com [209.85.223.174]) by kanga.kvack.org (Postfix) with ESMTP id 51D956B0038 for ; Wed, 2 Dec 2015 11:06:15 -0500 (EST) Received: by iofh3 with SMTP id h3so50405994iof.3 for ; Wed, 02 Dec 2015 08:06:15 -0800 (PST) Received: from resqmta-ch2-04v.sys.comcast.net (resqmta-ch2-04v.sys.comcast.net. [2001:558:fe21:29:69:252:207:36]) by mx.google.com with ESMTPS id m25si6389557ioi.189.2015.12.02.08.06.14 for (version=TLS1_2 cipher=AES128-SHA bits=128/128); Wed, 02 Dec 2015 08:06:14 -0800 (PST) Date: Wed, 2 Dec 2015 10:06:13 -0600 (CST) From: Christoph Lameter Subject: Re: [PATCH 3/3] mm/slab: use list_{empty_careful,last_entry} in drain_freelist In-Reply-To: <670c0018e0e4f44d6e788423b35e2c32ccf6c1e2.1449070964.git.geliangtang@163.com> Message-ID: References: <7e551749f5a50cef15a33320d6d33b9d0b0986bd.1449070964.git.geliangtang@163.com> <670c0018e0e4f44d6e788423b35e2c32ccf6c1e2.1449070964.git.geliangtang@163.com> Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Geliang Tang Cc: Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, 2 Dec 2015, Geliang Tang wrote: > diff --git a/mm/slab.c b/mm/slab.c > index 5d5aa3b..1a7d91c 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -2362,21 +2362,14 @@ static void drain_cpu_caches(struct kmem_cache *cachep) > static int drain_freelist(struct kmem_cache *cache, > struct kmem_cache_node *n, int tofree) > { > - struct list_head *p; > int nr_freed; > struct page *page; > > nr_freed = 0; > - while (nr_freed < tofree && !list_empty(&n->slabs_free)) { > + while (nr_freed < tofree && !list_empty_careful(&n->slabs_free)) { > > spin_lock_irq(&n->list_lock); > - p = n->slabs_free.prev; > - if (p == &n->slabs_free) { > - spin_unlock_irq(&n->list_lock); > - goto out; > - } > - > - page = list_entry(p, struct page, lru); > + page = list_last_entry(&n->slabs_free, struct page, lru); This is safe? Process could be rescheduled and lots of things could happen before disabling irqs. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org