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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4447BC433F5 for ; Tue, 12 Apr 2022 03:14:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344242AbiDLDQQ (ORCPT ); Mon, 11 Apr 2022 23:16:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241681AbiDLDQM (ORCPT ); Mon, 11 Apr 2022 23:16:12 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E074330F63 for ; Mon, 11 Apr 2022 20:13:56 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.57]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4KcrLB4tT3zBsCk; Tue, 12 Apr 2022 11:09:38 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 12 Apr 2022 11:13:54 +0800 Subject: Re: [PATCH v2 4/9] mm/vmscan: save a bit of stack space in shrink_lruvec To: "ying.huang@intel.com" , CC: , , , , References: <20220409093500.10329-1-linmiaohe@huawei.com> <20220409093500.10329-5-linmiaohe@huawei.com> <512fce32b8967ebc49f6fc074db408c117b510f7.camel@intel.com> From: Miaohe Lin Message-ID: <84b6946b-01ed-bc40-9da5-f62bf2b6de90@huawei.com> Date: Tue, 12 Apr 2022 11:13:54 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <512fce32b8967ebc49f6fc074db408c117b510f7.camel@intel.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/4/12 8:57, ying.huang@intel.com wrote: > On Sat, 2022-04-09 at 17:34 +0800, Miaohe Lin wrote: >> LRU_UNEVICTABLE is not taken into account when shrink lruvec. So we can >> save a bit of stack space by shrinking the array size of nr and targets >> to NR_LRU_LISTS - 1. No functional change intended. >> >> Signed-off-by: Miaohe Lin >> --- >>  mm/vmscan.c | 5 +++-- >>  1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index 59b96320f481..0e5818970998 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -2881,8 +2881,9 @@ static bool can_age_anon_pages(struct pglist_data *pgdat, >>   >> >>  static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) >>  { >> - unsigned long nr[NR_LRU_LISTS]; >> - unsigned long targets[NR_LRU_LISTS]; >> + /* LRU_UNEVICTABLE is not taken into account. */ >> + unsigned long nr[NR_LRU_LISTS - 1]; >> + unsigned long targets[NR_LRU_LISTS - 1]; >>   unsigned long nr_to_scan; >>   enum lru_list lru; >>   unsigned long nr_reclaimed = 0; > > As Christoph pointed out, this is hacky without much benefit. Please > drop this patch. Will drop this patch. Thanks. > > Best Regards, > Huang, Ying > > . >