Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760481AbbLCOxX (ORCPT ); Thu, 3 Dec 2015 09:53:23 -0500 Received: from resqmta-ch2-08v.sys.comcast.net ([69.252.207.40]:52849 "EHLO resqmta-ch2-08v.sys.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751222AbbLCOxW (ORCPT ); Thu, 3 Dec 2015 09:53:22 -0500 Date: Thu, 3 Dec 2015 08:53:21 -0600 (CST) From: Christoph Lameter X-X-Sender: cl@east.gentwo.org To: Geliang Tang cc: Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/slab.c: use list_{empty_careful,last_entry} in drain_freelist In-Reply-To: <3ea815dc52bf1a2bb5e324d7398315597900be84.1449151365.git.geliangtang@163.com> Message-ID: References: <3ea815dc52bf1a2bb5e324d7398315597900be84.1449151365.git.geliangtang@163.com> Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 955 Lines: 30 On Thu, 3 Dec 2015, Geliang Tang wrote: > while (nr_freed < tofree && !list_empty(&n->slabs_free)) { > > spin_lock_irq(&n->list_lock); > - p = n->slabs_free.prev; > - if (p == &n->slabs_free) { > + if (list_empty_careful(&n->slabs_free)) { We have taken the lock. Why do we need to be "careful"? list_empty() shoudl work right? > 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); last??? Would the the other new function that returns NULL on the empty list or the pointer not be useful here too and save some code? This patch seems to make it difficult to understand the code. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/