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=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 D710BC49EA7 for ; Fri, 25 Jun 2021 07:33:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BEE5661427 for ; Fri, 25 Jun 2021 07:33:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230092AbhFYHgA (ORCPT ); Fri, 25 Jun 2021 03:36:00 -0400 Received: from mga02.intel.com ([134.134.136.20]:21955 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229900AbhFYHfo (ORCPT ); Fri, 25 Jun 2021 03:35:44 -0400 IronPort-SDR: QdW2GneXjRcvwm0uPtz+KFJAU1JEVrDNBh4Vhlloiuy7631TmJrwJrINlMXejQU2yH8y8wUnnr YW5EuQe/asXw== X-IronPort-AV: E=McAfee;i="6200,9189,10025"; a="194769118" X-IronPort-AV: E=Sophos;i="5.83,298,1616482800"; d="scan'208";a="194769118" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jun 2021 00:33:23 -0700 IronPort-SDR: 2icSWzt6rWD+2fbPcof3C2ftYHnf8CgTFEGMhJuMQbta5jytMGXZk9CLADDun3rSaZkqZ5Cpuw KygWu+rK+PmA== X-IronPort-AV: E=Sophos;i="5.83,298,1616482800"; d="scan'208";a="488085867" Received: from msun2-mobl1.ccr.corp.intel.com (HELO yhuang6-mobl1.ccr.corp.intel.com) ([10.254.215.50]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jun 2021 00:33:17 -0700 From: Huang Ying To: linux-mm@kvack.org Cc: 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 -V9 6/9] mm/vmscan: add helper for querying ability to age anonymous pages Date: Fri, 25 Jun 2021 15:32:01 +0800 Message-Id: <20210625073204.1005986-7-ying.huang@intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210625073204.1005986-1-ying.huang@intel.com> References: <20210625073204.1005986-1-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 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 | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 78b3bae71520..55f6192b2a51 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2716,6 +2716,26 @@ 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 anon_can_be_aged(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: */ + if (!sc->no_demotion && + next_demotion_node(pgdat->node_id) != NUMA_NO_NODE) + return true; + + /* No way to reclaim anon pages. Should not age anon LRUs: */ + return false; +} + static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) { unsigned long nr[NR_LRU_LISTS]; @@ -2825,7 +2845,8 @@ 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 (anon_can_be_aged(lruvec_pgdat(lruvec), sc) && + inactive_is_low(lruvec, LRU_INACTIVE_ANON)) shrink_active_list(SWAP_CLUSTER_MAX, lruvec, sc, LRU_ACTIVE_ANON); } @@ -3654,7 +3675,7 @@ static void age_active_anon(struct pglist_data *pgdat, struct mem_cgroup *memcg; struct lruvec *lruvec; - if (!total_swap_pages) + if (!anon_can_be_aged(pgdat, sc)) return; lruvec = mem_cgroup_lruvec(NULL, pgdat); -- 2.30.2