From patchwork Thu Mar 10 12:07:49 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oscar Salvador X-Patchwork-Id: 12776246 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41551C433EF for ; Thu, 10 Mar 2022 12:08:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A751E8D0002; Thu, 10 Mar 2022 07:08:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A23808D0001; Thu, 10 Mar 2022 07:08:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8EA968D0002; Thu, 10 Mar 2022 07:08:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.26]) by kanga.kvack.org (Postfix) with ESMTP id 7DEC38D0001 for ; Thu, 10 Mar 2022 07:08:00 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 3DFD221AD4 for ; Thu, 10 Mar 2022 12:08:00 +0000 (UTC) X-FDA: 79228353120.15.8BD0570 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf27.hostedemail.com (Postfix) with ESMTP id 7C1FB4001B for ; Thu, 10 Mar 2022 12:07:59 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 20CC4210EE; Thu, 10 Mar 2022 12:07:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1646914078; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=NvOIhGb4c7ibfsrwnpf1GR5D9S3hNFtbc8sbDAT5k4c=; b=zBzigt546QEHFQo/7qGoTwnB+uGWItDOhOqE9BJVtj6lD3B91SjltcEB7F3YJzPDug06t4 wZOtndhu7JS4J4hV9A0UeHbIlZeIMR30zC3Tpgn8aKZx3bZdVQfgm3Q9UMhJXVnlN+pvx6 6eBloQN/clJNUdlo88lr+yAUZsvx80U= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1646914078; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=NvOIhGb4c7ibfsrwnpf1GR5D9S3hNFtbc8sbDAT5k4c=; b=4LbdAVShRUMXHbSpmh8P54xkYCeICL2OmYVmb/p59TWa0cZG8xpeLxP7JnXaYpwz7bNguf kdqDSSbd0jRVIzCw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 63A6C13FA3; Thu, 10 Mar 2022 12:07:57 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id lMX1FB3qKWLAIAAAMHmgww (envelope-from ); Thu, 10 Mar 2022 12:07:57 +0000 From: Oscar Salvador To: Andrew Morton Cc: Dave Hansen , "Huang, Ying" , Abhishek Goel , Baolin Wang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Oscar Salvador Subject: [PATCH v2] mm: Only re-generate demotion targets when a numa node changes its N_CPU state Date: Thu, 10 Mar 2022 13:07:49 +0100 Message-Id: <20220310120749.23077-1-osalvador@suse.de> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 7C1FB4001B X-Rspam-User: Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=zBzigt54; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=4LbdAVSh; spf=pass (imf27.hostedemail.com: domain of osalvador@suse.de designates 195.135.220.28 as permitted sender) smtp.mailfrom=osalvador@suse.de; dmarc=pass (policy=none) header.from=suse.de X-Stat-Signature: ngp4jaksjjdcjn6bqnd8r8chwfkk1goq X-HE-Tag: 1646914079-385033 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: Abhishek reported that after patch [1], hotplug operations are taking ~double the expected time. [2] The reason behind is that the CPU callbacks that migrate_on_reclaim_init() sets always call set_migration_target_nodes() whenever a CPU is brought up/down. But we only care about numa nodes going from having cpus to become cpuless, and vice versa, as that influences the demotion_target order. We do already have two CPU callbacks (vmstat_cpu_online() and vmstat_cpu_dead()) that check exactly that, so get rid of the CPU callbacks in migrate_on_reclaim_init() and only call set_migration_target_nodes() from vmstat_cpu_{dead,online}() whenever a numa node change its N_CPU state. [1] https://lore.kernel.org/linux-mm/20210721063926.3024591-2-ying.huang@intel.com/ [2] https://lore.kernel.org/linux-mm/eb438ddd-2919-73d4-bd9f-b7eecdd9577a@linux.vnet.ibm.com/ Reported-by: Abhishek Goel Signed-off-by: Oscar Salvador Reviewed-by: Baolin Wang Tested-by: Baolin Wang --- v1 -> v2: - Fix prototype function declaration - Fix build error on RISC - Adressed feedback from Baolin and Huang --- include/linux/migrate.h | 8 ++++++++ mm/migrate.c | 41 +++++------------------------------------ mm/vmstat.c | 13 ++++++++++++- 3 files changed, 25 insertions(+), 37 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index db96e10eb8da..90e75d5a54d6 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -48,7 +48,15 @@ int folio_migrate_mapping(struct address_space *mapping, struct folio *newfolio, struct folio *folio, int extra_count); extern bool numa_demotion_enabled; +extern void migrate_on_reclaim_init(void); +#ifdef CONFIG_HOTPLUG_CPU +extern void set_migration_target_nodes(void); #else +static inline void set_migration_target_nodes(void) {} +#endif +#else + +static inline void set_migration_target_nodes(void) {} static inline void putback_movable_pages(struct list_head *l) {} static inline int migrate_pages(struct list_head *l, new_page_t new, diff --git a/mm/migrate.c b/mm/migrate.c index c7da064b4781..f9d5b6092a42 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -3190,7 +3190,7 @@ static void __set_migration_target_nodes(void) /* * For callers that do not hold get_online_mems() already. */ -static void set_migration_target_nodes(void) +void set_migration_target_nodes(void) { get_online_mems(); __set_migration_target_nodes(); @@ -3254,51 +3254,20 @@ static int __meminit migrate_on_reclaim_callback(struct notifier_block *self, return notifier_from_errno(0); } -/* - * React to hotplug events that might affect the migration targets - * 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) +void __init migrate_on_reclaim_init(void) { - set_migration_target_nodes(); - return 0; -} - -static int migration_offline_cpu(unsigned int cpu) -{ - set_migration_target_nodes(); - return 0; -} - -static int __init migrate_on_reclaim_init(void) -{ - int ret; - node_demotion = kmalloc_array(nr_node_ids, sizeof(struct demotion_nodes), GFP_KERNEL); WARN_ON(!node_demotion); - ret = cpuhp_setup_state_nocalls(CPUHP_MM_DEMOTION_DEAD, "mm/demotion:offline", - NULL, 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. + * At this point, all numa nodes with memory/CPus have their state + * properly set, so we can build the demotion order now. */ - WARN_ON(ret < 0); - ret = cpuhp_setup_state(CPUHP_AP_MM_DEMOTION_ONLINE, "mm/demotion:online", - migration_online_cpu, NULL); - WARN_ON(ret < 0); - + set_migration_target_nodes(); hotplug_memory_notifier(migrate_on_reclaim_callback, 100); - return 0; } -late_initcall(migrate_on_reclaim_init); #endif /* CONFIG_HOTPLUG_CPU */ bool numa_demotion_enabled = false; diff --git a/mm/vmstat.c b/mm/vmstat.c index 4057372745d0..9e9536df51b5 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -28,6 +28,7 @@ #include #include #include +#include #include "internal.h" @@ -2043,7 +2044,12 @@ static void __init init_cpu_node_state(void) static int vmstat_cpu_online(unsigned int cpu) { refresh_zone_stat_thresholds(); - node_set_state(cpu_to_node(cpu), N_CPU); + + if (!node_state(cpu_to_node(cpu), N_CPU)) { + node_set_state(cpu_to_node(cpu), N_CPU); + set_migration_target_nodes(); + } + return 0; } @@ -2066,6 +2072,8 @@ static int vmstat_cpu_dead(unsigned int cpu) return 0; node_clear_state(node, N_CPU); + set_migration_target_nodes(); + return 0; } @@ -2097,6 +2105,9 @@ void __init init_mm_internals(void) start_shepherd_timer(); #endif +#if defined(CONFIG_MIGRATION) && defined(CONFIG_HOTPLUG_CPU) + migrate_on_reclaim_init(); +#endif #ifdef CONFIG_PROC_FS proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op); proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);