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 70197C433FE for ; Tue, 12 Apr 2022 01:11:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230519AbiDLBNt (ORCPT ); Mon, 11 Apr 2022 21:13:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351246AbiDLBBO (ORCPT ); Mon, 11 Apr 2022 21:01:14 -0400 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7DB91C108 for ; Mon, 11 Apr 2022 17:57:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1649725056; x=1681261056; h=message-id:subject:from:to:cc:date:in-reply-to: references:mime-version:content-transfer-encoding; bh=Aud1C1bU0YFrT2OMMryfkkUmardBCvVa+5tOlJ4O+fg=; b=O0FPf9QmgoRLJ+iTyaD4FZ5QHmlY+QozS0yCRAPl8CnxeVnP2e+LY+lc 9hxI+1C6bJVkvEBTs47suMB4onVIVwQP5JZDVm9owuGFMb9sVywEFwQBj pLM9PRYa0tOViu4cBLkXvtlCX6KuFdBOasIaqHGches1KyteUKpyPsASg nCaMviq6+bPPwrt8WKYGTZzWryvMGBjdVb+2VpawcykFjSYdh50LO3eZa J5utRIE83s/v3KdTKf2fyH+fHHyQULMjoRbmCRkVS3U2BsGRAopgUH4xG CvrxoDZ6AMGRKIjdbwjn83WQ+HQzxTxcsZ/DrzNgEYbZWwSVuVFEyZCQP Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10314"; a="244132534" X-IronPort-AV: E=Sophos;i="5.90,252,1643702400"; d="scan'208";a="244132534" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Apr 2022 17:57:36 -0700 X-IronPort-AV: E=Sophos;i="5.90,252,1643702400"; d="scan'208";a="572493910" Received: from joliu-mobl2.ccr.corp.intel.com ([10.254.214.243]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Apr 2022 17:57:34 -0700 Message-ID: <512fce32b8967ebc49f6fc074db408c117b510f7.camel@intel.com> Subject: Re: [PATCH v2 4/9] mm/vmscan: save a bit of stack space in shrink_lruvec From: "ying.huang@intel.com" To: Miaohe Lin , akpm@linux-foundation.org Cc: songmuchun@bytedance.com, hch@infradead.org, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Date: Tue, 12 Apr 2022 08:57:31 +0800 In-Reply-To: <20220409093500.10329-5-linmiaohe@huawei.com> References: <20220409093500.10329-1-linmiaohe@huawei.com> <20220409093500.10329-5-linmiaohe@huawei.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.3-1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Best Regards, Huang, Ying