From patchwork Sun Apr 30 17:18:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yury Norov X-Patchwork-Id: 13227250 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A402EC7EE21 for ; Sun, 30 Apr 2023 17:18:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231721AbjD3RSb (ORCPT ); Sun, 30 Apr 2023 13:18:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230494AbjD3RS0 (ORCPT ); Sun, 30 Apr 2023 13:18:26 -0400 Received: from mail-pl1-x635.google.com (mail-pl1-x635.google.com [IPv6:2607:f8b0:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5C023595; Sun, 30 Apr 2023 10:18:18 -0700 (PDT) Received: by mail-pl1-x635.google.com with SMTP id d9443c01a7336-1a6715ee82fso18149665ad.1; Sun, 30 Apr 2023 10:18:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1682875098; x=1685467098; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=8TFT+ESKwfU7QbMQhW5p+wdCiH0luZnBdTAjBAnH2Fg=; b=ke83Ke+83g4oZWBNC3U1aX00laf2hOH8TD69Tz/ZlUHkydQwQRS1g9KeTxEeoX+J8x uYblxYNvIflf+Fu+r4ZaDO/s2Q1MeRkMBriys0/OWj72TrfVWCYMFaX+y/69V/hU1K74 G5L6m7HJUCZOUaHzyauz3hhZ63ODntNV+4yhgWueT1CpXcuLifDiI/i26UP5R5VzDB06 JGWI8WnUd7Dyi+gU8pyPla2d4u8AjpYRSBv+02yxTEq89z6J82m8aHfqR8CccE1A7vtA tqxZYEVSxAqy2ejWmCsWkNyVNDBwu0E4tPDQRxCfL5Bf9y+2hMnQNvkWz5Y8V3/QSyyj sesg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682875098; x=1685467098; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=8TFT+ESKwfU7QbMQhW5p+wdCiH0luZnBdTAjBAnH2Fg=; b=i6dsQtTOOK3m+2AWx7ZcMd+BeY+zmv4cABYcJsAaol6q/iBibvsO0FhGlvBDFmamny 84fE9ekJM4C74m/kD7vto9G2BVxouzrC3DPfrZt2WAut9AJNdXJCG0MvvTF9WL8AEAHU 23i91rWjOKJNHBe9wjDpVtdSo6Bm2TFnCYRkW4iQ7Gqj1fsvacdwrtnjqgmIN6koLFyu H0UA0cdVf/XK7GByoRwE4jJQ2Vj8HcnmJCy9gnVThNv2qobFvJbnUbvxSC5M1Im5mpz0 mSrVXfoN61MT4CONGcGVlrw9NUvcojXzDxuy1oQ7ZRaB99Q+TP1ZPpDvYCUVMV0kus7V ClHw== X-Gm-Message-State: AC+VfDxbr/wEX6aAiuvXAk9svYnibBrv/WeDuhT/2ioNjFici2SsUMkm X9NS0wCpIt77Vycu1xDb5wg= X-Google-Smtp-Source: ACHHUZ7frQxXvjq2TJpWQpvURgwj288wakVEzbaYwn3v9PW599mlWCVhQWHWq9Txfex7+SrmiThJoQ== X-Received: by 2002:a17:902:ec92:b0:1a6:9079:2bb3 with SMTP id x18-20020a170902ec9200b001a690792bb3mr16126156plg.33.1682875098056; Sun, 30 Apr 2023 10:18:18 -0700 (PDT) Received: from localhost ([4.1.102.3]) by smtp.gmail.com with ESMTPSA id u4-20020a170902b28400b001a64851087bsm16447001plr.272.2023.04.30.10.18.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Apr 2023 10:18:17 -0700 (PDT) From: Yury Norov To: Jakub Kicinski , netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Yury Norov , Saeed Mahameed , Pawel Chmielewski , Leon Romanovsky , "David S. Miller" , Eric Dumazet , Paolo Abeni , Andy Shevchenko , Rasmus Villemoes , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , Tariq Toukan , Gal Pressman , Greg Kroah-Hartman , Heiko Carstens , Barry Song Subject: [PATCH v3 4/8] sched/topology: add for_each_numa_{,online}_cpu() macro Date: Sun, 30 Apr 2023 10:18:05 -0700 Message-Id: <20230430171809.124686-5-yury.norov@gmail.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20230430171809.124686-1-yury.norov@gmail.com> References: <20230430171809.124686-1-yury.norov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org for_each_cpu() is widely used in the kernel, and it's beneficial to create a NUMA-aware version of the macro. Recently added for_each_numa_hop_mask() works, but switching existing codebase to using it is not an easy process. New for_each_numa_cpu() is designed to be similar to the for_each_cpu(). It allows to convert existing code to NUMA-aware as simple as adding a hop iterator variable and passing it inside new macro. for_each_numa_cpu() takes care of the rest. At the moment, we have 2 users of NUMA-aware enumerators. One is Melanox's in-tree driver, and another is Intel's in-review driver: https://lore.kernel.org/lkml/20230216145455.661709-1-pawel.chmielewski@intel.com/ Both real-life examples follow the same pattern: for_each_numa_hop_mask(cpus, prev, node) { for_each_cpu_andnot(cpu, cpus, prev) { if (cnt++ == max_num) goto out; do_something(cpu); } prev = cpus; } With the new macro, it would look like this: for_each_numa_online_cpu(cpu, hop, node) { if (cnt++ == max_num) break; do_something(cpu); } Straight conversion of existing for_each_cpu() codebase to NUMA-aware version with for_each_numa_hop_mask() is difficult because it doesn't take a user-provided cpu mask, and eventually ends up with open-coded double loop. With for_each_numa_cpu() it shouldn't be a brainteaser. Consider the NUMA-ignorant example: cpumask_t cpus = get_mask(); int cnt = 0, cpu; for_each_cpu(cpu, cpus) { if (cnt++ == max_num) break; do_something(cpu); } Converting it to NUMA-aware version would be as simple as: cpumask_t cpus = get_mask(); int node = get_node(); int cnt = 0, hop, cpu; for_each_numa_cpu(cpu, hop, node, cpus) { if (cnt++ == max_num) break; do_something(cpu); } The latter looks more verbose and avoids from open-coding that annoying double loop. Another advantage is that it works with a 'hop' parameter with the clear meaning of NUMA distance, and doesn't make people not familiar to enumerator internals bothering with current and previous masks machinery. Signed-off-by: Yury Norov --- include/linux/topology.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/include/linux/topology.h b/include/linux/topology.h index da92fea38585..6ed01962878c 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -291,4 +291,23 @@ sched_numa_hop_mask(unsigned int node, unsigned int hops) !IS_ERR_OR_NULL(mask); \ __hops++) +/** + * for_each_numa_cpu - iterate over cpus in increasing order taking into account + * NUMA distances from a given node. + * @cpu: the (optionally unsigned) integer iterator + * @hop: the iterator variable, must be initialized to a desired minimal hop. + * @node: the NUMA node to start the search from. + * @mask: the cpumask pointer + * + * Requires rcu_lock to be held. + */ +#define for_each_numa_cpu(cpu, hop, node, mask) \ + for ((cpu) = 0, (hop) = 0; \ + (cpu) = sched_numa_find_next_cpu((mask), (cpu), (node), &(hop)),\ + (cpu) < nr_cpu_ids; \ + (cpu)++) + +#define for_each_numa_online_cpu(cpu, hop, node) \ + for_each_numa_cpu(cpu, hop, node, cpu_online_mask) + #endif /* _LINUX_TOPOLOGY_H */