From patchwork Mon Jan 18 17:12:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Charan Teja Kalla X-Patchwork-Id: 12027911 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 0C966C433DB for ; Mon, 18 Jan 2021 17:12:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A959F22CA0 for ; Mon, 18 Jan 2021 17:12:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A959F22CA0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D287E8D001E; Mon, 18 Jan 2021 12:12:50 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CB1B18D0017; Mon, 18 Jan 2021 12:12:50 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B79B68D001E; Mon, 18 Jan 2021 12:12:50 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0150.hostedemail.com [216.40.44.150]) by kanga.kvack.org (Postfix) with ESMTP id 98C6A8D0017 for ; Mon, 18 Jan 2021 12:12:50 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 5EE731EE6 for ; Mon, 18 Jan 2021 17:12:50 +0000 (UTC) X-FDA: 77719540500.19.rub14_49043342754a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id 2EB551ACC2C for ; Mon, 18 Jan 2021 17:12:50 +0000 (UTC) X-HE-Tag: rub14_49043342754a X-Filterd-Recvd-Size: 7195 Received: from so254-31.mailgun.net (so254-31.mailgun.net [198.61.254.31]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Mon, 18 Jan 2021 17:12:47 +0000 (UTC) DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1610989969; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=7N0AL8N+d/LCg3DbSCNYLJGazZNXw3CzCrYyrHMBb6E=; b=vMY4RyUWYG7K9aeu/GqUv1U78hW6yN6/oEYsM2xXKl1J8TlvsiwhsDPBt3hmkwOA2fp5aQgI 8IwI9IdUQacnmsWUcmP1BhglZX6HCSv0Loo6MvDmHJWKUwxFiNlFbfaaNmZrqltxhL0mnf5m r0Zx2XHK5v7oWUaG6OpQwKAfruI= X-Mailgun-Sending-Ip: 198.61.254.31 X-Mailgun-Sid: WyIwY2Q3OCIsICJsaW51eC1tbUBrdmFjay5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-east-1.postgun.com with SMTP id 6005c1881e3bf9b6692b1d06 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 18 Jan 2021 17:12:40 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 4BDD9C433C6; Mon, 18 Jan 2021 17:12:39 +0000 (UTC) Received: from charante-linux.qualcomm.com (unknown [202.46.22.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: charante) by smtp.codeaurora.org (Postfix) with ESMTPSA id DF24AC433CA; Mon, 18 Jan 2021 17:12:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org DF24AC433CA Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=charante@codeaurora.org From: Charan Teja Reddy To: akpm@linux-foundation.org, vbabka@suse.cz, mhocko@suse.com, khalid.aziz@oracle.com, ngupta@nitingupta.dev, vinmenon@codeaurora.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Charan Teja Reddy Subject: [PATCH V3] mm/compaction: correct deferral logic for proactive compaction Date: Mon, 18 Jan 2021 22:42:18 +0530 Message-Id: <1610989938-31374-1-git-send-email-charante@codeaurora.org> X-Mailer: git-send-email 2.7.4 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: should_proactive_compact_node() returns true when sum of the weighted fragmentation score of all the zones in the node is greater than the wmark_high of compaction, which then triggers the proactive compaction that operates on the individual zones of the node. But proactive compaction runs on the zone only when its weighted fragmentation score is greater than wmark_low(=wmark_high - 10). This means that the sum of the weighted fragmentation scores of all the zones can exceed the wmark_high but individual weighted fragmentation zone scores can still be less than wmark_low which makes the unnecessary trigger of the proactive compaction only to return doing nothing. Issue with the return of proactive compaction with out even trying is its deferral. It is simply deferred for 1 << COMPACT_MAX_DEFER_SHIFT if the scores across the proactive compaction is same, thinking that compaction didn't make any progress but in reality it didn't even try. With the delay between successive retries for proactive compaction is 500msec, it can result into the deferral for ~30sec with out even trying the proactive compaction. Test scenario is that: compaction_proactiveness=50 thus the wmark_low = 50 and wmark_high = 60. System have 2 zones(Normal and Movable) with sizes 5GB and 6GB respectively. After opening some apps on the android, the weighted fragmentation scores of these zones are 47 and 49 respectively. Since the sum of these fragmentation scores are above the wmark_high which triggers the proactive compaction and there since the individual zones weighted fragmentation scores are below wmark_low, it returns without trying the proactive compaction. As a result the weighted fragmentation scores of the zones are still 47 and 49 which makes the existing logic to defer the compaction thinking that noprogress is made across the compaction. Fix this by checking just zone fragmentation score, not the weighted, in __compact_finished() and use the zones weighted fragmentation score in fragmentation_score_node(). In the test case above, If the weighted average of is above wmark_high, then individual score (not adjusted) of atleast one zone has to be above wmark_high. Thus it avoids the unnecessary trigger and deferrals of the proactive compaction. Fix-suggested-by: Vlastimil Babka Signed-off-by: Charan Teja Reddy Acked-by: Vlastimil Babka Reviewed-by: Khalid Aziz Acked-by: David Rientjes --- Changes in V3: Addressed suggestions from Vlastimil Changes in V2: https://lore.kernel.org/patchwork/patch/1366862/ Changes in V1: https://lore.kernel.org/patchwork/patch/1364646/ mm/compaction.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index e5acb97..ccddb3a 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1925,20 +1925,28 @@ static bool kswapd_is_running(pg_data_t *pgdat) /* * A zone's fragmentation score is the external fragmentation wrt to the - * COMPACTION_HPAGE_ORDER scaled by the zone's size. It returns a value - * in the range [0, 100]. + * COMPACTION_HPAGE_ORDER. It returns a value in the range [0, 100]. + */ +static unsigned int fragmentation_score_zone(struct zone *zone) +{ + return extfrag_for_order(zone, COMPACTION_HPAGE_ORDER); +} + +/* + * A weighted zone's fragmentation score is the external fragmentation + * wrt to the COMPACTION_HPAGE_ORDER scaled by the zone's size. It + * returns a value in the range [0, 100]. * * The scaling factor ensures that proactive compaction focuses on larger * zones like ZONE_NORMAL, rather than smaller, specialized zones like * ZONE_DMA32. For smaller zones, the score value remains close to zero, * and thus never exceeds the high threshold for proactive compaction. */ -static unsigned int fragmentation_score_zone(struct zone *zone) +static unsigned int fragmentation_score_zone_weighted(struct zone *zone) { unsigned long score; - score = zone->present_pages * - extfrag_for_order(zone, COMPACTION_HPAGE_ORDER); + score = zone->present_pages * fragmentation_score_zone(zone); return div64_ul(score, zone->zone_pgdat->node_present_pages + 1); } @@ -1958,7 +1966,7 @@ static unsigned int fragmentation_score_node(pg_data_t *pgdat) struct zone *zone; zone = &pgdat->node_zones[zoneid]; - score += fragmentation_score_zone(zone); + score += fragmentation_score_zone_weighted(zone); } return score;