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=-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 86F84C433E0 for ; Tue, 26 Jan 2021 00:41:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3925F21D93 for ; Tue, 26 Jan 2021 00:41:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3925F21D93 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 9F13B8D0068; Mon, 25 Jan 2021 19:41:47 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9712B8D0069; Mon, 25 Jan 2021 19:41:47 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 79CC18D0068; Mon, 25 Jan 2021 19:41:47 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0137.hostedemail.com [216.40.44.137]) by kanga.kvack.org (Postfix) with ESMTP id 575158D0065 for ; Mon, 25 Jan 2021 19:41:47 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 287C01EE6 for ; Tue, 26 Jan 2021 00:41:47 +0000 (UTC) X-FDA: 77746073454.27.join48_130ac412758a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin27.hostedemail.com (Postfix) with ESMTP id F27F13D668 for ; Tue, 26 Jan 2021 00:41:46 +0000 (UTC) X-HE-Tag: join48_130ac412758a X-Filterd-Recvd-Size: 6525 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Tue, 26 Jan 2021 00:41:46 +0000 (UTC) IronPort-SDR: OXZiYEQhPrzNSM3ULfd6c5I1bovRCIGkf87b2jAjWzEPU3Qm0jcwrtMXZO2oow1kQ9dMbRU148 ixGSUtdi3slg== X-IronPort-AV: E=McAfee;i="6000,8403,9875"; a="167500496" X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="167500496" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jan 2021 16:41:44 -0800 IronPort-SDR: PjZAmHZ3H+ri1AAuXp0LSzLrLXT8f16sbk3mCFfOmBkY5c25vEFmYlggoQPl7hGhpma7s9aiGO 4s4wgQU4meEg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="353265040" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga003.jf.intel.com with ESMTP; 25 Jan 2021 16:41:42 -0800 Subject: [RFC][PATCH 06/13] mm/migrate: update migration order during on hotplug events To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org,Dave Hansen ,yang.shi@linux.alibaba.com,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 16:34:23 -0800 References: <20210126003411.2AC51464@viggo.jf.intel.com> In-Reply-To: <20210126003411.2AC51464@viggo.jf.intel.com> Message-Id: <20210126003423.8D2B5637@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 Reclaim-based migration is attempting to optimize data placement in memory based on the system topology. If the system changes, so must the migration ordering. The implementation here is pretty simple and entirely unoptimized. On any memory or CPU hotplug events, assume that a node was added or removed and recalculate all migration targets. This ensures that the node_demotion[] array is always ready to be used in case the new reclaim mode is enabled. This recalculation is far from optimal, most glaringly that it does not even attempt to figure out if nodes are actually coming or going. But, given the expected paucity of hotplug events, this should be fine. Signed-off-by: Dave Hansen Cc: Yang Shi Cc: David Rientjes Cc: Huang Ying Cc: Dan Williams Cc: David Hildenbrand Cc: osalvador --- b/mm/migrate.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 95 insertions(+), 2 deletions(-) diff -puN mm/migrate.c~enable-numa-demotion mm/migrate.c --- a/mm/migrate.c~enable-numa-demotion 2021-01-25 16:23:11.850866703 -0800 +++ b/mm/migrate.c 2021-01-25 16:23:11.855866703 -0800 @@ -49,6 +49,7 @@ #include #include #include +#include #include @@ -3135,6 +3136,7 @@ void migrate_vma_finalize(struct migrate EXPORT_SYMBOL(migrate_vma_finalize); #endif /* CONFIG_DEVICE_PRIVATE */ +#if defined(CONFIG_MEMORY_HOTPLUG) /* Disable reclaim-based migration. */ static void disable_all_migrate_targets(void) { @@ -3191,7 +3193,7 @@ static int establish_migrate_target(int * with itself. Exclusion is provided by memory hotplug events * being single-threaded. */ -void __set_migration_target_nodes(void) +static void __set_migration_target_nodes(void) { nodemask_t next_pass = NODE_MASK_NONE; nodemask_t this_pass = NODE_MASK_NONE; @@ -3253,9 +3255,100 @@ again: goto again; } -void set_migration_target_nodes(void) +/* + * For callers that do not hold get_online_mems() already. + */ +static void set_migration_target_nodes(void) { get_online_mems(); __set_migration_target_nodes(); put_online_mems(); } + +/* + * React to hotplug events that might affect the migration targes + * like events that online or offline NUMA nodes. + * + * The ordering is also currently dependent on which nodes have + * CPUs. That means we need CPU on/offline notification too. + */ +static int migration_online_cpu(unsigned int cpu) +{ + set_migration_target_nodes(); + return 0; +} + +static int migration_offline_cpu(unsigned int cpu) +{ + set_migration_target_nodes(); + return 0; +} + +/* + * This leaves migrate-on-reclaim transiently disabled + * between the MEM_GOING_OFFLINE and MEM_OFFLINE events. + * This runs reclaim-based micgration is enabled or not. + * This ensures that the user can turn reclaim-based + * migration at any time without needing to recalcuate + * migration targets. + * + * These callbacks already hold get_online_mems(). That + * is why __set_migration_target_nodes() can be used as + * opposed to set_migration_target_nodes(). + */ +static int __meminit migrate_on_reclaim_callback(struct notifier_block *self, + unsigned long action, void *arg) +{ + switch (action) { + case MEM_GOING_OFFLINE: + /* + * Make sure there are not transient states where + * an offline node is a migration target. This + * will leave migration disabled until the offline + * completes and the MEM_OFFLINE case below runs. + */ + disable_all_migrate_targets(); + break; + case MEM_OFFLINE: + case MEM_ONLINE: + /* + * Recalculate the target nodes once the node + * reaches its final state (online or offline). + */ + __set_migration_target_nodes(); + break; + case MEM_CANCEL_OFFLINE: + /* + * MEM_GOING_OFFLINE disabled all the migration + * targets. Reenable them. + */ + __set_migration_target_nodes(); + break; + case MEM_GOING_ONLINE: + case MEM_CANCEL_ONLINE: + break; + } + + return notifier_from_errno(0); +} + +static int __init migrate_on_reclaim_init(void) +{ + int ret; + + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "migrate on reclaim", + migration_online_cpu, + migration_offline_cpu); + /* + * In the unlikely case that this fails, the automatic + * migration targets may become suboptimal for nodes + * where N_CPU changes. With such a small impact in a + * rare case, do not bother trying to do anything special. + */ + WARN_ON(ret < 0); + + hotplug_memory_notifier(migrate_on_reclaim_callback, 100); + return 0; +} +late_initcall(migrate_on_reclaim_init); +#endif /* CONFIG_MEMORY_HOTPLUG */ _