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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 ACB50C433EF for ; Mon, 6 Sep 2021 01:21:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 968F161151 for ; Mon, 6 Sep 2021 01:21:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239437AbhIFBWq (ORCPT ); Sun, 5 Sep 2021 21:22:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:37738 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238843AbhIFBV3 (ORCPT ); Sun, 5 Sep 2021 21:21:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2E8E261027; Mon, 6 Sep 2021 01:20:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1630891226; bh=M2DLKss7Og2FyRfWehhKqs0LFhzzVoCrlvZh2pKx/zQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qh4GCxJ5UV4PNzP+WxGqzLfd36vX6a3L+loXdMJlJCeYfx1yX+vq4qPlcUjFO8DHA cFGdgw9d2eI5GLjBGPkBPGm4wp6hPjFtlmS44QcV2AavFRyMxLW49Kh9Qtz/NxV3Wt HToE/tJpO3kIZpU0MULzWWjMJtrsQ1wQ5/6LWivLPxa5bOw+ugNk7sm9SN74wYcjDB 0u/tUH/ZvpKw8vS9VfsbBfevhRib5dCdTtdJXC93pOicgAhI9hVRs0t3U3hYLM/5jO yRjpvcWu6QEOZjv/MwYsbvHk7D53tnpCbK+RZV+S1ON2u1jHBU7DHrlRI1Q4ciPpKG b4AcK/q+JtzGg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Valentin Schneider , Geetika Moolchandani , Srikar Dronamraju , Peter Zijlstra , Sasha Levin Subject: [PATCH AUTOSEL 5.14 28/47] sched/topology: Skip updating masks for non-online nodes Date: Sun, 5 Sep 2021 21:19:32 -0400 Message-Id: <20210906011951.928679-28-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210906011951.928679-1-sashal@kernel.org> References: <20210906011951.928679-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Valentin Schneider [ Upstream commit 0083242c93759dde353a963a90cb351c5c283379 ] The scheduler currently expects NUMA node distances to be stable from init onwards, and as a consequence builds the related data structures once-and-for-all at init (see sched_init_numa()). Unfortunately, on some architectures node distance is unreliable for offline nodes and may very well change upon onlining. Skip over offline nodes during sched_init_numa(). Track nodes that have been onlined at least once, and trigger a build of a node's NUMA masks when it is first onlined post-init. Reported-by: Geetika Moolchandani Signed-off-by: Srikar Dronamraju Signed-off-by: Valentin Schneider Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20210818074333.48645-1-srikar@linux.vnet.ibm.com Signed-off-by: Sasha Levin --- kernel/sched/topology.c | 65 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index b77ad49dc14f..4e8698e62f07 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1482,6 +1482,8 @@ int sched_max_numa_distance; static int *sched_domains_numa_distance; static struct cpumask ***sched_domains_numa_masks; int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE; + +static unsigned long __read_mostly *sched_numa_onlined_nodes; #endif /* @@ -1833,6 +1835,16 @@ void sched_init_numa(void) sched_domains_numa_masks[i][j] = mask; for_each_node(k) { + /* + * Distance information can be unreliable for + * offline nodes, defer building the node + * masks to its bringup. + * This relies on all unique distance values + * still being visible at init time. + */ + if (!node_online(j)) + continue; + if (sched_debug() && (node_distance(j, k) != node_distance(k, j))) sched_numa_warn("Node-distance not symmetric"); @@ -1886,6 +1898,53 @@ void sched_init_numa(void) sched_max_numa_distance = sched_domains_numa_distance[nr_levels - 1]; init_numa_topology_type(); + + sched_numa_onlined_nodes = bitmap_alloc(nr_node_ids, GFP_KERNEL); + if (!sched_numa_onlined_nodes) + return; + + bitmap_zero(sched_numa_onlined_nodes, nr_node_ids); + for_each_online_node(i) + bitmap_set(sched_numa_onlined_nodes, i, 1); +} + +static void __sched_domains_numa_masks_set(unsigned int node) +{ + int i, j; + + /* + * NUMA masks are not built for offline nodes in sched_init_numa(). + * Thus, when a CPU of a never-onlined-before node gets plugged in, + * adding that new CPU to the right NUMA masks is not sufficient: the + * masks of that CPU's node must also be updated. + */ + if (test_bit(node, sched_numa_onlined_nodes)) + return; + + bitmap_set(sched_numa_onlined_nodes, node, 1); + + for (i = 0; i < sched_domains_numa_levels; i++) { + for (j = 0; j < nr_node_ids; j++) { + if (!node_online(j) || node == j) + continue; + + if (node_distance(j, node) > sched_domains_numa_distance[i]) + continue; + + /* Add remote nodes in our masks */ + cpumask_or(sched_domains_numa_masks[i][node], + sched_domains_numa_masks[i][node], + sched_domains_numa_masks[0][j]); + } + } + + /* + * A new node has been brought up, potentially changing the topology + * classification. + * + * Note that this is racy vs any use of sched_numa_topology_type :/ + */ + init_numa_topology_type(); } void sched_domains_numa_masks_set(unsigned int cpu) @@ -1893,8 +1952,14 @@ void sched_domains_numa_masks_set(unsigned int cpu) int node = cpu_to_node(cpu); int i, j; + __sched_domains_numa_masks_set(node); + for (i = 0; i < sched_domains_numa_levels; i++) { for (j = 0; j < nr_node_ids; j++) { + if (!node_online(j)) + continue; + + /* Set ourselves in the remote node's masks */ if (node_distance(j, node) <= sched_domains_numa_distance[i]) cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); } -- 2.30.2