From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754995Ab1G2G2J (ORCPT ); Fri, 29 Jul 2011 02:28:09 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:50074 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754590Ab1G2G2H (ORCPT ); Fri, 29 Jul 2011 02:28:07 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Message-ID: <4E3252E2.1030101@jp.fujitsu.com> Date: Fri, 29 Jul 2011 15:27:46 +0900 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20110624 Thunderbird/5.0 MIME-Version: 1.0 To: jj@chaosbits.net CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org, riel@redhat.com, minchan.kim@gmail.com, mgorman@suse.de, akpm@linux-foundation.org, kanoj@sgi.com, sct@redhat.com Subject: Re: [PATCH] vmscan: Remove if statement that will never trigger References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2011/07/29 6:05), Jesper Juhl wrote: > We have this code in mm/vmscan.c:shrink_slab() : > ... > if (total_scan < 0) { > printk(KERN_ERR "shrink_slab: %pF negative objects to " > "delete nr=%ld\n", > shrinker->shrink, total_scan); > total_scan = max_pass; > } > ... > but since 'total_scan' is of type 'unsigned long' it will never be > less than zero, so there is no way we'll ever enter the true branch of > this if statement - so let's just remove it. > > Signed-off-by: Jesper Juhl > --- > mm/vmscan.c | 6 ------ > 1 files changed, 0 insertions(+), 6 deletions(-) > > Compile tested only. > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 7ef6912..c07d9b1 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -271,12 +271,6 @@ unsigned long shrink_slab(struct shrink_control *shrink, > delta *= max_pass; > do_div(delta, lru_pages + 1); > total_scan += delta; > - if (total_scan < 0) { > - printk(KERN_ERR "shrink_slab: %pF negative objects to " > - "delete nr=%ld\n", > - shrinker->shrink, total_scan); > - total_scan = max_pass; > - } > > /* > * We need to avoid excessive windup on filesystem shrinkers Good catch. However this seems intended to catch a overflow. So, I'd suggest to make proper overflow check instead.