From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966069AbcIHKFr (ORCPT ); Thu, 8 Sep 2016 06:05:47 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:43298 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938353AbcIHKFp (ORCPT ); Thu, 8 Sep 2016 06:05:45 -0400 Date: Thu, 8 Sep 2016 12:03:02 +0200 (CEST) From: Thomas Gleixner To: Fenghua Yu cc: "H. Peter Anvin" , Ingo Molnar , Tony Luck , Peter Zijlstra , Tejun Heo , Borislav Petkov , Stephane Eranian , Marcelo Tosatti , David Carrillo-Cisneros , Shaohua Li , Ravi V Shankar , Vikas Shivappa , Sai Prakhya , linux-kernel , x86 Subject: Re: [PATCH v2 11/33] x86/intel_rdt: Hot cpu support for Cache Allocation In-Reply-To: <1473328647-33116-12-git-send-email-fenghua.yu@intel.com> Message-ID: References: <1473328647-33116-1-git-send-email-fenghua.yu@intel.com> <1473328647-33116-12-git-send-email-fenghua.yu@intel.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 8 Sep 2016, Fenghua Yu wrote: > +/* > + * cbm_update_msrs() - Updates all the existing IA32_L3_MASK_n MSRs > + * which are one per CLOSid on the current package. > + */ > +static void cbm_update_msrs(void *dummy) > +{ > + int maxid = boot_cpu_data.x86_cache_max_closid; > + struct rdt_remote_data info; > + unsigned int i; > + > + for (i = 0; i < maxid; i++) { > + if (cctable[i].clos_refcnt) { > + info.msr = CBM_FROM_INDEX(i); > + info.val = cctable[i].cbm; > + msr_cpu_update(&info); > + } > + } > +} > + > +static int intel_rdt_online_cpu(unsigned int cpu) > +{ > + struct intel_pqr_state *state = &per_cpu(pqr_state, cpu); > + > + state->closid = 0; > + mutex_lock(&rdtgroup_mutex); > + /* The cpu is set in root rdtgroup after online. */ > + cpumask_set_cpu(cpu, &root_rdtgrp->cpu_mask); > + per_cpu(cpu_rdtgroup, cpu) = root_rdtgrp; > + /* > + * If the cpu is first time found and set in its siblings that -ENOPARSE > + * share the same cache, update the CBM MSRs for the cache. > + */ > + if (rdt_cpumask_update(cpu)) > + smp_call_function_single(cpu, cbm_update_msrs, NULL, 1); This smp_call_function() is a pointless exercise. online callbacks are guaranteed to run on @cpu. > + mutex_unlock(&rdtgroup_mutex); > +} > + > +static int clear_rdtgroup_cpumask(unsigned int cpu) > +{ > + struct list_head *l; > + struct rdtgroup *r; > + > + list_for_each(l, &rdtgroup_lists) { > + r = list_entry(l, struct rdtgroup, rdtgroup_list); > + if (cpumask_test_cpu(cpu, &r->cpu_mask)) { > + cpumask_clear_cpu(cpu, &r->cpu_mask); > + return 0; > + } > + } > + > + return -EINVAL; What's the point of the return value if it gets ignored anyway. > +} > + > +static int intel_rdt_offline_cpu(unsigned int cpu) > +{ > + int i; > + > + mutex_lock(&rdtgroup_mutex); > + if (!cpumask_test_and_clear_cpu(cpu, &rdt_cpumask)) { > + mutex_unlock(&rdtgroup_mutex); > + return; > + } > + > + cpumask_and(&tmp_cpumask, topology_core_cpumask(cpu), cpu_online_mask); > + cpumask_clear_cpu(cpu, &tmp_cpumask); > + i = cpumask_any(&tmp_cpumask); > + > + if (i < nr_cpu_ids) > + cpumask_set_cpu(i, &rdt_cpumask); > + > + clear_rdtgroup_cpumask(cpu); > + mutex_unlock(&rdtgroup_mutex); > +} > + > static int __init intel_rdt_late_init(void) > { > struct cpuinfo_x86 *c = &boot_cpu_data; > @@ -169,6 +247,13 @@ static int __init intel_rdt_late_init(void) > > for_each_online_cpu(i) > rdt_cpumask_update(i); > + > + ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, > + "AP_INTEL_RDT_ONLINE", > + intel_rdt_online_cpu, intel_rdt_offline_cpu); Why are you using nocalls() here? cpuhp_setup_state() will invoke intel_rdt_online_cpu() on every online cpu. And you just call rdt_cpumask_update() for each cpu. What is doing the rest of the cpu initialization (cpu_rdtgroup, root_rtgroup->cpu_mask) ???? > + if (err < 0) > + goto out_err; Oh well..... Thanks, tglx