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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 F40F2C433E0 for ; Thu, 14 Jan 2021 01:59:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B82C523442 for ; Thu, 14 Jan 2021 01:59:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728377AbhANB60 (ORCPT ); Wed, 13 Jan 2021 20:58:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:54176 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729487AbhAMXl4 (ORCPT ); Wed, 13 Jan 2021 18:41:56 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E860222248; Wed, 13 Jan 2021 23:40:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1610581222; bh=7LOErbfKYvmtc32PcRxhq0yDGVjhmozc2wzfzgsMZAc=; h=Date:From:To:Subject:From; b=1p6DcW7HYhtOftWL9udDN3kvnmk7XOwqGbvckdz8Foy5kMy2MFiUoHuBoWvQHODov Zg/MQ1eY20gFUmAaJmjNbuOSAD02QHxp7V7uqkECHmGnZllpYT+3tdNDQqHUUjj/oB Av2GC6Jhw8OsAkEhiIBQu/BXNe1Yg86p3D/iB5tc= Date: Wed, 13 Jan 2021 15:40:21 -0800 From: akpm@linux-foundation.org To: charante@codeaurora.org, khalid.aziz@oracle.com, mgorman@techsingularity.net, mhocko@suse.com, mm-commits@vger.kernel.org, ngupta@nitingupta.dev, vbabka@suse.cz, vinmenon@codeaurora.org Subject: + mm-compaction-return-proper-state-in-should_proactive_compact_node.patch added to -mm tree Message-ID: <20210113234021.uYvIAiUrk%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/compaction: return proper state in should_proactive_compact_node has been added to the -mm tree. Its filename is mm-compaction-return-proper-state-in-should_proactive_compact_node.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-compaction-return-proper-state-in-should_proactive_compact_node.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-compaction-return-proper-state-in-should_proactive_compact_node.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Charan Teja Reddy Subject: mm/compaction: return proper state in should_proactive_compact_node should_proactive_compact_node() returns true when sum of the 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 the fragmentation score of the zone is greater than wmark_low(=wmark_high - 10). This means that the sum of the fragmentation scores of all the zones can exceed the wmark_high but individual zone scores can still be less than the wmark_low which makes the unnecessary trigger of the proactive compaction only to return doing nothing. Another 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 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 zone scores are below wmark_low, it returns without trying the compaction. As a result the 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. So, run the proactive compaction on the node zones only when atleast one of the zones fragmentation score is greater than wmark_low. This avoids the unnecessary deferral and retries of the compaction. Link: https://lkml.kernel.org/r/1610546586-18998-1-git-send-email-charante@codeaurora.org Signed-off-by: Charan Teja Reddy Cc: Michal Hocko Cc: Vlastimil Babka Cc: Khalid Aziz Cc: Nitin Gupta Cc: Vinayak Menon Cc: Mel Gorman Signed-off-by: Andrew Morton --- mm/compaction.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) --- a/mm/compaction.c~mm-compaction-return-proper-state-in-should_proactive_compact_node +++ a/mm/compaction.c @@ -1961,6 +1961,26 @@ static unsigned int fragmentation_score_ return score; } +/* + * Returns the maximum of fragmentation scores of zones in a node. This is + * used in taking the decission of whether to trigger the proactive compaction + * on the zones of this node. + */ +static unsigned int fragmentation_score_node_zones_max(pg_data_t *pgdat) +{ + int zoneid; + unsigned int max = 0; + + for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { + struct zone *zone; + + zone = &pgdat->node_zones[zoneid]; + max = max_t(unsigned int, fragmentation_score_zone(zone), max); + } + + return max; +} + static unsigned int fragmentation_score_wmark(pg_data_t *pgdat, bool low) { unsigned int wmark_low; @@ -1976,13 +1996,16 @@ static unsigned int fragmentation_score_ static bool should_proactive_compact_node(pg_data_t *pgdat) { - int wmark_high; + int wmark_low, wmark_high; if (!sysctl_compaction_proactiveness || kswapd_is_running(pgdat)) return false; wmark_high = fragmentation_score_wmark(pgdat, false); - return fragmentation_score_node(pgdat) > wmark_high; + wmark_low = fragmentation_score_wmark(pgdat, true); + + return fragmentation_score_node(pgdat) > wmark_high && + fragmentation_score_node_zones_max(pgdat) > wmark_low; } static enum compact_result __compact_finished(struct compact_control *cc) _ Patches currently in -mm which might be from charante@codeaurora.org are mm-compaction-return-proper-state-in-should_proactive_compact_node.patch