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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECEB8FA373D for ; Tue, 25 Oct 2022 00:33:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230187AbiJYAda (ORCPT ); Mon, 24 Oct 2022 20:33:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230301AbiJYAdG (ORCPT ); Mon, 24 Oct 2022 20:33:06 -0400 Received: from mail-oa1-x2b.google.com (mail-oa1-x2b.google.com [IPv6:2001:4860:4864:20::2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95B3A1870B3; Mon, 24 Oct 2022 15:57:51 -0700 (PDT) Received: by mail-oa1-x2b.google.com with SMTP id 586e51a60fabf-13be3ef361dso1160802fac.12; Mon, 24 Oct 2022 15:57:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=1jpnB9M+lUx8mTalc2CYaRAaH+zKMlWayKR7/3tTIjY=; b=j9MmxsxfjV2DuOk7P5Ux5Y+5R1CpOqJSNPgK4sF7YQ7bw7OnTQIR+PMalDScdE/TKy yc/QWE9eRaB4O/LXBPMTsrN2Yi3QVGP7fdPKrRDFNGRXL750HrQ2rhTdJ8rrS5eTYyN3 rz4Hr4BeRUC0ST1p2kbCMOR+iya7QcfI5Sb9l/gjbtqaUhiNm7V6mt0O4K8UnRIgV4MA gBjGb07q1B2gM9cP92HGwOHh7mrtO/kSocPpJTAhX+eHlOjr7QknACj0lILgiMsIuwsZ mTIBuurjOssrj9duju52AkEtx+9pxZvEcuy37RTNt62UGpBbTbj1GUmFgCten8UfdE+Q 81+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=1jpnB9M+lUx8mTalc2CYaRAaH+zKMlWayKR7/3tTIjY=; b=bqvELFJAGQzI9FcnBzvB8fV2YLj0RgsAasRYg/TGGvI1zmt7ZXGp/z7Qzes1FH/G0z pAOd37Nj2Q+5DGlzdfDYjXSv4W4pgAc2t8Hc8sCCacLkiMm6oe96TgNjNF2dQdOhhoSr bYmvPfhQDnqduS8Vqawri5Ispdt9/tjaFA6JeYpJVow6bntK1xOaHncc1GPF3KJv/0Sw ZtSWAg4GsDwR4Ay8TwOMEpJwy/Um8CenKxo4i/9xtUtXziluDqDv7n1h0j/TF4oabuGq kUumM1JNdGgxj+P4K3QyEUazwskQmw1Pwg5F+yPo4OGwlvixAutHcP4grbSlEtd5IoQd ZQNw== X-Gm-Message-State: ACrzQf2rO663xozRtF/wd53ZmLWlEcZTA3wlZbichDAClOVVtPromkN2 Z+kybMtZjw+G9OzX98GlTAE= X-Google-Smtp-Source: AMsMyM5zgvkPSBXX+IVnlSujLJDxh8HsomYjzwa1p6+AVd0jfSMWxBiL0+JuZxRUpmeCgz+VZndmVQ== X-Received: by 2002:a05:6870:4612:b0:13b:775d:511 with SMTP id z18-20020a056870461200b0013b775d0511mr6795289oao.81.1666652270682; Mon, 24 Oct 2022 15:57:50 -0700 (PDT) Received: from localhost ([12.97.180.36]) by smtp.gmail.com with ESMTPSA id 9-20020a9d0689000000b006618f1fbb84sm298520otx.80.2022.10.24.15.57.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Oct 2022 15:57:50 -0700 (PDT) Date: Mon, 24 Oct 2022 15:55:38 -0700 From: Yury Norov To: Valentin Schneider Cc: netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, Saeed Mahameed , Leon Romanovsky , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Andy Shevchenko , Rasmus Villemoes , Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Mel Gorman , Greg Kroah-Hartman , Heiko Carstens , Tony Luck , Jonathan Cameron , Gal Pressman , Tariq Toukan , Jesse Brandeburg Subject: Re: [PATCH v5 1/3] sched/topology: Introduce sched_numa_hop_mask() Message-ID: References: <20221021121927.2893692-1-vschneid@redhat.com> <20221021121927.2893692-2-vschneid@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221021121927.2893692-2-vschneid@redhat.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Oct 21, 2022 at 01:19:25PM +0100, Valentin Schneider wrote: > Tariq has pointed out that drivers allocating IRQ vectors would benefit > from having smarter NUMA-awareness - cpumask_local_spread() only knows > about the local node and everything outside is in the same bucket. Can you keep 1st-person references in a cover letter? > sched_domains_numa_masks is pretty much what we want to hand out (a cpumask > of CPUs reachable within a given distance budget), introduce > sched_numa_hop_mask() to export those cpumasks. > > Link: http://lore.kernel.org/r/20220728191203.4055-1-tariqt@nvidia.com > Signed-off-by: Valentin Schneider > --- > include/linux/topology.h | 12 ++++++++++++ > kernel/sched/topology.c | 31 +++++++++++++++++++++++++++++++ > 2 files changed, 43 insertions(+) > > diff --git a/include/linux/topology.h b/include/linux/topology.h > index 4564faafd0e12..3e91ae6d0ad58 100644 > --- a/include/linux/topology.h > +++ b/include/linux/topology.h > @@ -245,5 +245,17 @@ static inline const struct cpumask *cpu_cpu_mask(int cpu) > return cpumask_of_node(cpu_to_node(cpu)); > } > > +#ifdef CONFIG_NUMA > +extern const struct cpumask *sched_numa_hop_mask(int node, int hops); > +#else > +static inline const struct cpumask *sched_numa_hop_mask(int node, int hops) > +{ > + if (node == NUMA_NO_NODE && !hops) > + return cpu_online_mask; > + > + return ERR_PTR(-EOPNOTSUPP); > +} > +#endif /* CONFIG_NUMA */ > + > > #endif /* _LINUX_TOPOLOGY_H */ > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c > index 8739c2a5a54ea..e3cb8cc375204 100644 > --- a/kernel/sched/topology.c > +++ b/kernel/sched/topology.c > @@ -2067,6 +2067,37 @@ int sched_numa_find_closest(const struct cpumask *cpus, int cpu) > return found; > } > > +/** > + * sched_numa_hop_mask() - Get the cpumask of CPUs at most @hops hops away from > + * @node > + * @node: The node to count hops from. > + * @hops: Include CPUs up to that many hops away. 0 means local node. > + * > + * Return: On success, a pointer to a cpumask of CPUs at most @hops away from > + * @node, an error value otherwise. > + * > + * Requires rcu_lock to be held. Returned cpumask is only valid within that > + * read-side section, copy it if required beyond that. > + * > + * Note that not all hops are equal in distance; see sched_init_numa() for how > + * distances and masks are handled. > + * Also note that this is a reflection of sched_domains_numa_masks, which may change > + * during the lifetime of the system (offline nodes are taken out of the masks). > + */ > +const struct cpumask *sched_numa_hop_mask(unsigned int node, unsigned int hops) > +{ > + struct cpumask ***masks = rcu_dereference(sched_domains_numa_masks); > + > + if (node >= nr_node_ids || hops >= sched_domains_numa_levels) > + return ERR_PTR(-EINVAL); Can you dereference rcu things after sanity checks? > + if (!masks) > + return ERR_PTR(-EBUSY); > + > + return masks[hops][node]; > +} > +EXPORT_SYMBOL_GPL(sched_numa_hop_mask); > + > #endif /* CONFIG_NUMA */ > > static int __sdt_alloc(const struct cpumask *cpu_map) > -- > 2.31.1