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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 89D12C43331 for ; Mon, 11 Nov 2019 18:35:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CE8821783 for ; Mon, 11 Nov 2019 18:35:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573497329; bh=1gwTMekgjt67z7fCm6yRqttyHTJmowUzZ/pjtGgvDOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PXyplAOFnYapE/WqhyfLWbSmeIoG9qPTrE4Txn2qYaa2fYipL/RHBtTofUAmCJTWZ 63YfD/4fe7WGcQoMWTiPq5cjbm6z0/+kUu5B2te58smeLFsrPFPvLFwQ+Sz4QJBkE6 cU4lDTLnUkL2OUFtoaodXz5cWA/eGEJ2fdpuSfMs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728530AbfKKSf1 (ORCPT ); Mon, 11 Nov 2019 13:35:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:53286 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727312AbfKKSf0 (ORCPT ); Mon, 11 Nov 2019 13:35:26 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 42B7320659; Mon, 11 Nov 2019 18:35:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573497324; bh=1gwTMekgjt67z7fCm6yRqttyHTJmowUzZ/pjtGgvDOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=epmvPLukHTAQgu+LdGE8ytLNClOqsR05t3/oBYNgtVd8/9dlnFgECJiq+xDHhIvj6 Qg1DOaB875YoNbcB1HfpASQ3lSfa7zqySDtiykU5S+m9m/+UZfpqeEqt1Sd43Pbgwr l9mjqBd0bOy0W0uBRilxAutZpr9GcAZNM80p7azI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mel Gorman , Michal Hocko , Vlastimil Babka , David Hildenbrand , Matt Fleming , Thomas Gleixner , Borislav Petkov , Qian Cai , Andrew Morton , Linus Torvalds Subject: [PATCH 4.14 015/105] mm, meminit: recalculate pcpu batch and high limits after init completes Date: Mon, 11 Nov 2019 19:27:45 +0100 Message-Id: <20191111181431.387847886@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191111181421.390326245@linuxfoundation.org> References: <20191111181421.390326245@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mel Gorman commit 3e8fc0075e24338b1117cdff6a79477427b8dbed upstream. Deferred memory initialisation updates zone->managed_pages during the initialisation phase but before that finishes, the per-cpu page allocator (pcpu) calculates the number of pages allocated/freed in batches as well as the maximum number of pages allowed on a per-cpu list. As zone->managed_pages is not up to date yet, the pcpu initialisation calculates inappropriately low batch and high values. This increases zone lock contention quite severely in some cases with the degree of severity depending on how many CPUs share a local zone and the size of the zone. A private report indicated that kernel build times were excessive with extremely high system CPU usage. A perf profile indicated that a large chunk of time was lost on zone->lock contention. This patch recalculates the pcpu batch and high values after deferred initialisation completes for every populated zone in the system. It was tested on a 2-socket AMD EPYC 2 machine using a kernel compilation workload -- allmodconfig and all available CPUs. mmtests configuration: config-workload-kernbench-max Configuration was modified to build on a fresh XFS partition. kernbench 5.4.0-rc3 5.4.0-rc3 vanilla resetpcpu-v2 Amean user-256 13249.50 ( 0.00%) 16401.31 * -23.79%* Amean syst-256 14760.30 ( 0.00%) 4448.39 * 69.86%* Amean elsp-256 162.42 ( 0.00%) 119.13 * 26.65%* Stddev user-256 42.97 ( 0.00%) 19.15 ( 55.43%) Stddev syst-256 336.87 ( 0.00%) 6.71 ( 98.01%) Stddev elsp-256 2.46 ( 0.00%) 0.39 ( 84.03%) 5.4.0-rc3 5.4.0-rc3 vanilla resetpcpu-v2 Duration User 39766.24 49221.79 Duration System 44298.10 13361.67 Duration Elapsed 519.11 388.87 The patch reduces system CPU usage by 69.86% and total build time by 26.65%. The variance of system CPU usage is also much reduced. Before, this was the breakdown of batch and high values over all zones was: 256 batch: 1 256 batch: 63 512 batch: 7 256 high: 0 256 high: 378 512 high: 42 512 pcpu pagesets had a batch limit of 7 and a high limit of 42. After the patch: 256 batch: 1 768 batch: 63 256 high: 0 768 high: 378 [mgorman@techsingularity.net: fix merge/linkage snafu] Link: http://lkml.kernel.org/r/20191023084705.GD3016@techsingularity.netLink: http://lkml.kernel.org/r/20191021094808.28824-2-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Michal Hocko Acked-by: Vlastimil Babka Acked-by: David Hildenbrand Cc: Matt Fleming Cc: Thomas Gleixner Cc: Borislav Petkov Cc: Qian Cai Cc: [4.1+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/page_alloc.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1998,6 +1998,14 @@ static void steal_suitable_fallback(stru old_block_type = get_pageblock_migratetype(page); /* + * The number of managed pages has changed due to the initialisation + * so the pcpu batch and high limits needs to be updated or the limits + * will be artificially small. + */ + for_each_populated_zone(zone) + zone_pcp_update(zone); + + /* * This can happen due to races and we want to prevent broken * highatomic accounting. */ @@ -7659,7 +7667,6 @@ void free_contig_range(unsigned long pfn } #endif -#ifdef CONFIG_MEMORY_HOTPLUG /* * The zone indicated has a new number of managed_pages; batch sizes and percpu * page high values need to be recalulated. @@ -7673,7 +7680,6 @@ void __meminit zone_pcp_update(struct zo per_cpu_ptr(zone->pageset, cpu)); mutex_unlock(&pcp_batch_high_lock); } -#endif void zone_pcp_reset(struct zone *zone) {