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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 D756DC07E96 for ; Thu, 15 Jul 2021 05:52:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0A96611C0 for ; Thu, 15 Jul 2021 05:52:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240064AbhGOFz2 (ORCPT ); Thu, 15 Jul 2021 01:55:28 -0400 Received: from mga02.intel.com ([134.134.136.20]:22887 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239994AbhGOFzZ (ORCPT ); Thu, 15 Jul 2021 01:55:25 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10045"; a="197661960" X-IronPort-AV: E=Sophos;i="5.84,240,1620716400"; d="scan'208";a="197661960" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2021 22:52:32 -0700 X-IronPort-AV: E=Sophos;i="5.84,240,1620716400"; d="scan'208";a="505591629" Received: from yhuang6-mobl1.sh.intel.com ([10.238.6.138]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2021 22:52:29 -0700 From: Huang Ying To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dave Hansen , "Huang, Ying" , Yang Shi , Greg Thelen , Michal Hocko , Wei Xu , osalvador , Zi Yan , David Rientjes , Dan Williams , David Hildenbrand Subject: [PATCH -V10 6/9] mm/vmscan: add helper for querying ability to age anonymous pages Date: Thu, 15 Jul 2021 13:51:42 +0800 Message-Id: <20210715055145.195411-7-ying.huang@intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210715055145.195411-1-ying.huang@intel.com> References: <20210715055145.195411-1-ying.huang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen Anonymous pages are kept on their own LRU(s). These lists could theoretically always be scanned and maintained. But, without swap, there is currently nothing the kernel can *do* with the results of a scanned, sorted LRU for anonymous pages. A check for '!total_swap_pages' currently serves as a valid check as to whether anonymous LRUs should be maintained. However, another method will be added shortly: page demotion. Abstract out the 'total_swap_pages' checks into a helper, give it a logically significant name, and check for the possibility of page demotion. Signed-off-by: Dave Hansen Signed-off-by: "Huang, Ying" Reviewed-by: Yang Shi Reviewed-by: Greg Thelen Cc: Michal Hocko Cc: Wei Xu Cc: osalvador Cc: Zi Yan Cc: David Rientjes Cc: Dan Williams Cc: David Hildenbrand Changes since 20210625: * Rename function to be more consistent with other similar functions. Changes since 20210618: * Rename function per Oscar's comments. * Change parameter per Wei's comments. * Make the function static. * Consider whether demotion is disabled. --- mm/vmscan.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 35913e35369d..302f8d6e7b65 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2724,6 +2724,21 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, } } +/* + * Anonymous LRU management is a waste if there is + * ultimately no way to reclaim the memory. + */ +static bool can_age_anon_pages(struct pglist_data *pgdat, + struct scan_control *sc) +{ + /* Aging the anon LRU is valuable if swap is present: */ + if (total_swap_pages > 0) + return true; + + /* Also valuable if anon pages can be demoted: */ + return can_demote_anon_pages(pgdat->node_id, sc); +} + static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) { unsigned long nr[NR_LRU_LISTS]; @@ -2833,7 +2848,8 @@ static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) * Even if we did not try to evict anon pages at all, we want to * rebalance the anon lru active/inactive ratio. */ - if (total_swap_pages && inactive_is_low(lruvec, LRU_INACTIVE_ANON)) + if (can_age_anon_pages(lruvec_pgdat(lruvec), sc) && + inactive_is_low(lruvec, LRU_INACTIVE_ANON)) shrink_active_list(SWAP_CLUSTER_MAX, lruvec, sc, LRU_ACTIVE_ANON); } @@ -3662,7 +3678,7 @@ static void age_active_anon(struct pglist_data *pgdat, struct mem_cgroup *memcg; struct lruvec *lruvec; - if (!total_swap_pages) + if (!can_age_anon_pages(pgdat, sc)) return; lruvec = mem_cgroup_lruvec(NULL, pgdat); -- 2.30.2