From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18466C388F9 for ; Tue, 27 Oct 2020 17:21:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B495720809 for ; Tue, 27 Oct 2020 17:21:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="pTvlvA8l" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1818658AbgJ0RVk (ORCPT ); Tue, 27 Oct 2020 13:21:40 -0400 Received: from m12-15.163.com ([220.181.12.15]:54574 "EHLO m12-15.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1795239AbgJ0RVi (ORCPT ); Tue, 27 Oct 2020 13:21:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=Date:From:Subject:Message-ID:MIME-Version; bh=7iC1B g63LnwLLyjyKl+KfHw1n3wjgF5SyvewtftGbW8=; b=pTvlvA8lpXFsnDPlnTUpq VqIxb5kQGIVq+goQmwZSgck2RaXBAEeQpcA3XhbsXy09d3CLA9/2BVPdFJ41XquE fsEK9QqrAXci31PYUp4Lv8YBOokmEhkXHDI3cVQc5+LPskLXrRkI8i0aoVhVKb4d 5MC40oNMxV10/sYr4KK4Os= Received: from localhost (unknown [101.86.209.121]) by smtp11 (Coremail) with SMTP id D8CowADHlfIUU5hfgOmYFA--.51943S2; Wed, 28 Oct 2020 01:04:20 +0800 (CST) Date: Wed, 28 Oct 2020 01:04:20 +0800 From: Hui Su To: akpm@linux-foundation.org, gustavo@embeddedor.com, sh_def@163.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH] mm/list_lru: optimize condition of exiting the loop Message-ID: <20201027170420.GA61326@rlk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-CM-TRANSID: D8CowADHlfIUU5hfgOmYFA--.51943S2 X-Coremail-Antispam: 1Uf129KBjvJXoWrtryDtr47uF1fur4UJrW8WFg_yoW8Jr4Upa n09rW7KFyxXF48u3y8J39ruF10grWUCrW7KrZruw1jyw13JFZxX39FkrW2qF98XFWxXFyf GryDCF45uF4UGwUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07UJwIkUUUUU= X-Originating-IP: [101.86.209.121] X-CM-SenderInfo: xvkbvvri6rljoofrz/1tbiIBTKX10TB9dVFAAAs+ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In list_lru_walk(), nr_to_walk type is 'unsigned long', so nr_to_walk won't be '< 0'. In list_lru_walk_node(), nr_to_walk type is 'unsigned long', so *nr_to_walk won't be '< 0' too. We can use '!nr_to_walk' instead of 'nr_to_walk <= 0', which is more precise. Signed-off-by: Hui Su --- include/linux/list_lru.h | 2 +- mm/list_lru.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h index 9dcaa3e582c9..b7bc4a2636b9 100644 --- a/include/linux/list_lru.h +++ b/include/linux/list_lru.h @@ -214,7 +214,7 @@ list_lru_walk(struct list_lru *lru, list_lru_walk_cb isolate, for_each_node_state(nid, N_NORMAL_MEMORY) { isolated += list_lru_walk_node(lru, nid, isolate, cb_arg, &nr_to_walk); - if (nr_to_walk <= 0) + if (!nr_to_walk) break; } return isolated; diff --git a/mm/list_lru.c b/mm/list_lru.c index 5aa6e44bc2ae..39b8d467159d 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -304,7 +304,7 @@ unsigned long list_lru_walk_node(struct list_lru *lru, int nid, nr_to_walk); spin_unlock(&nlru->lock); - if (*nr_to_walk <= 0) + if (!*nr_to_walk) break; } } -- 2.25.1