From patchwork Tue Jan 26 00:34:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Hansen X-Patchwork-Id: 12045011 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 3B58CC433DB for ; Tue, 26 Jan 2021 00:41:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E978F21D93 for ; Tue, 26 Jan 2021 00:41:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E978F21D93 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 903608D006C; Mon, 25 Jan 2021 19:41:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 810D48D0065; Mon, 25 Jan 2021 19:41:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 578B98D006C; Mon, 25 Jan 2021 19:41:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0219.hostedemail.com [216.40.44.219]) by kanga.kvack.org (Postfix) with ESMTP id 40DED8D0065 for ; Mon, 25 Jan 2021 19:41:52 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 0FB181EE6 for ; Tue, 26 Jan 2021 00:41:52 +0000 (UTC) X-FDA: 77746073664.22.queen04_1900d1e2758a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin22.hostedemail.com (Postfix) with ESMTP id DFC1918038E67 for ; Tue, 26 Jan 2021 00:41:51 +0000 (UTC) X-HE-Tag: queen04_1900d1e2758a X-Filterd-Recvd-Size: 4200 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Tue, 26 Jan 2021 00:41:50 +0000 (UTC) IronPort-SDR: Tw5fJd3A/lK5Y3NziMBkqosL/uUiq9BdFZySh+eaC5Fi29lxK/2EB7aE6Mt2Ry6Y4fC4thQQOp 7l5CW6Oa5Kvw== X-IronPort-AV: E=McAfee;i="6000,8403,9875"; a="167500502" X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="167500502" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jan 2021 16:41:50 -0800 IronPort-SDR: SqQbFya8pBJyjCISCrzIQsncIzU0SYhJtTH0YCI0M9R0reNoVgJoG4XNXagfqux3P5ECijZwyv F3190jrHZ2Wg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="429496854" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga001.jf.intel.com with ESMTP; 25 Jan 2021 16:41:50 -0800 Subject: [RFC][PATCH 10/13] mm/vmscan: add helper for querying ability to age anonymous pages To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org,Dave Hansen ,rientjes@google.com,ying.huang@intel.com,dan.j.williams@intel.com,david@redhat.com,osalvador@suse.de From: Dave Hansen Date: Mon, 25 Jan 2021 16:34:31 -0800 References: <20210126003411.2AC51464@viggo.jf.intel.com> In-Reply-To: <20210126003411.2AC51464@viggo.jf.intel.com> Message-Id: <20210126003431.19BDC239@viggo.jf.intel.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 Cc: David Rientjes Cc: Huang Ying Cc: Dan Williams Cc: David Hildenbrand Cc: osalvador --- b/mm/vmscan.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) diff -puN mm/vmscan.c~mm-vmscan-anon-can-be-aged mm/vmscan.c --- a/mm/vmscan.c~mm-vmscan-anon-can-be-aged 2021-01-25 16:23:17.044866690 -0800 +++ b/mm/vmscan.c 2021-01-25 16:23:17.053866690 -0800 @@ -2508,6 +2508,26 @@ out: } } +/* + * Anonymous LRU management is a waste if there is + * ultimately no way to reclaim the memory. + */ +bool anon_should_be_aged(struct lruvec *lruvec) +{ + struct pglist_data *pgdat = lruvec_pgdat(lruvec); + + /* 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 (next_demotion_node(pgdat->node_id) >= 0) + 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]; @@ -2617,7 +2637,8 @@ static void shrink_lruvec(struct lruvec * 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_should_be_aged(lruvec) && + inactive_is_low(lruvec, LRU_INACTIVE_ANON)) shrink_active_list(SWAP_CLUSTER_MAX, lruvec, sc, LRU_ACTIVE_ANON); } @@ -3446,10 +3467,11 @@ static void age_active_anon(struct pglis struct mem_cgroup *memcg; struct lruvec *lruvec; - if (!total_swap_pages) + lruvec = mem_cgroup_lruvec(NULL, pgdat); + + if (!anon_should_be_aged(lruvec)) return; - lruvec = mem_cgroup_lruvec(NULL, pgdat); if (!inactive_is_low(lruvec, LRU_INACTIVE_ANON)) return;