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Fri, 12 Jun 2020 05:12:49 +0000 Received: from b03ledav002.gho.boulder.ibm.com (b03ledav002.gho.boulder.ibm.com [9.17.130.233]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 05C5CmbV50200888 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 12 Jun 2020 05:12:48 GMT Received: from b03ledav002.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E77BC13604F; Fri, 12 Jun 2020 05:12:47 +0000 (GMT) Received: from b03ledav002.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 83757136055; Fri, 12 Jun 2020 05:12:47 +0000 (GMT) Received: from localhost (unknown [9.65.252.60]) by b03ledav002.gho.boulder.ibm.com (Postfix) with ESMTP; Fri, 12 Jun 2020 05:12:47 +0000 (GMT) From: Nathan Lynch To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH 09/18] powerpc/numa: stub out numa_update_cpu_topology() Date: Fri, 12 Jun 2020 00:12:29 -0500 Message-Id: <20200612051238.1007764-10-nathanl@linux.ibm.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200612051238.1007764-1-nathanl@linux.ibm.com> References: <20200612051238.1007764-1-nathanl@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.687 definitions=2020-06-11_23:2020-06-11, 2020-06-11 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 clxscore=1015 malwarescore=0 mlxlogscore=999 phishscore=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 bulkscore=0 cotscore=-2147483648 mlxscore=0 suspectscore=1 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006110174 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tyreld@linux.ibm.com, srikar@linux.vnet.ibm.com, ego@linux.vnet.ibm.com, npiggin@gmail.com, svaidy@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Previous changes have removed the code which sets bits in cpu_associativity_changes_mask and thus it is never modifed at runtime. From this we can reason that numa_update_cpu_topology() always returns 0 without doing anything. Remove the body of numa_update_cpu_topology() and remove all code which becomes unreachable as a result. Signed-off-by: Nathan Lynch --- arch/powerpc/mm/numa.c | 193 +---------------------------------------- 1 file changed, 1 insertion(+), 192 deletions(-) diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index 8749d7f2b1a6..b220e5b60140 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c @@ -1122,14 +1122,6 @@ u64 memory_hotplug_max(void) /* Virtual Processor Home Node (VPHN) support */ #ifdef CONFIG_PPC_SPLPAR -struct topology_update_data { - struct topology_update_data *next; - unsigned int cpu; - int old_nid; - int new_nid; -}; - -static cpumask_t cpu_associativity_changes_mask; static int topology_inited; /* @@ -1219,192 +1211,9 @@ int find_and_online_cpu_nid(int cpu) return new_nid; } -/* - * Update the CPU maps and sysfs entries for a single CPU when its NUMA - * characteristics change. This function doesn't perform any locking and is - * only safe to call from stop_machine(). - */ -static int update_cpu_topology(void *data) -{ - struct topology_update_data *update; - unsigned long cpu; - - if (!data) - return -EINVAL; - - cpu = smp_processor_id(); - - for (update = data; update; update = update->next) { - int new_nid = update->new_nid; - if (cpu != update->cpu) - continue; - - unmap_cpu_from_node(cpu); - map_cpu_to_node(cpu, new_nid); - set_cpu_numa_node(cpu, new_nid); - set_cpu_numa_mem(cpu, local_memory_node(new_nid)); - vdso_getcpu_init(); - } - - return 0; -} - -static int update_lookup_table(void *data) -{ - struct topology_update_data *update; - - if (!data) - return -EINVAL; - - /* - * Upon topology update, the numa-cpu lookup table needs to be updated - * for all threads in the core, including offline CPUs, to ensure that - * future hotplug operations respect the cpu-to-node associativity - * properly. - */ - for (update = data; update; update = update->next) { - int nid, base, j; - - nid = update->new_nid; - base = cpu_first_thread_sibling(update->cpu); - - for (j = 0; j < threads_per_core; j++) { - update_numa_cpu_lookup_table(base + j, nid); - } - } - - return 0; -} - -/* - * Update the node maps and sysfs entries for each cpu whose home node - * has changed. Returns 1 when the topology has changed, and 0 otherwise. - * - * cpus_locked says whether we already hold cpu_hotplug_lock. - */ int numa_update_cpu_topology(bool cpus_locked) { - unsigned int cpu, sibling, changed = 0; - struct topology_update_data *updates, *ud; - cpumask_t updated_cpus; - struct device *dev; - int weight, new_nid, i = 0; - - if (topology_inited) - return 0; - - weight = cpumask_weight(&cpu_associativity_changes_mask); - if (!weight) - return 0; - - updates = kcalloc(weight, sizeof(*updates), GFP_KERNEL); - if (!updates) - return 0; - - cpumask_clear(&updated_cpus); - - for_each_cpu(cpu, &cpu_associativity_changes_mask) { - /* - * If siblings aren't flagged for changes, updates list - * will be too short. Skip on this update and set for next - * update. - */ - if (!cpumask_subset(cpu_sibling_mask(cpu), - &cpu_associativity_changes_mask)) { - pr_info("Sibling bits not set for associativity " - "change, cpu%d\n", cpu); - cpumask_or(&cpu_associativity_changes_mask, - &cpu_associativity_changes_mask, - cpu_sibling_mask(cpu)); - cpu = cpu_last_thread_sibling(cpu); - continue; - } - - new_nid = find_and_online_cpu_nid(cpu); - - if (new_nid == numa_cpu_lookup_table[cpu]) { - cpumask_andnot(&cpu_associativity_changes_mask, - &cpu_associativity_changes_mask, - cpu_sibling_mask(cpu)); - dbg("Assoc chg gives same node %d for cpu%d\n", - new_nid, cpu); - cpu = cpu_last_thread_sibling(cpu); - continue; - } - - for_each_cpu(sibling, cpu_sibling_mask(cpu)) { - ud = &updates[i++]; - ud->next = &updates[i]; - ud->cpu = sibling; - ud->new_nid = new_nid; - ud->old_nid = numa_cpu_lookup_table[sibling]; - cpumask_set_cpu(sibling, &updated_cpus); - } - cpu = cpu_last_thread_sibling(cpu); - } - - /* - * Prevent processing of 'updates' from overflowing array - * where last entry filled in a 'next' pointer. - */ - if (i) - updates[i-1].next = NULL; - - pr_debug("Topology update for the following CPUs:\n"); - if (cpumask_weight(&updated_cpus)) { - for (ud = &updates[0]; ud; ud = ud->next) { - pr_debug("cpu %d moving from node %d " - "to %d\n", ud->cpu, - ud->old_nid, ud->new_nid); - } - } - - /* - * In cases where we have nothing to update (because the updates list - * is too short or because the new topology is same as the old one), - * skip invoking update_cpu_topology() via stop-machine(). This is - * necessary (and not just a fast-path optimization) since stop-machine - * can end up electing a random CPU to run update_cpu_topology(), and - * thus trick us into setting up incorrect cpu-node mappings (since - * 'updates' is kzalloc()'ed). - * - * And for the similar reason, we will skip all the following updating. - */ - if (!cpumask_weight(&updated_cpus)) - goto out; - - if (cpus_locked) - stop_machine_cpuslocked(update_cpu_topology, &updates[0], - &updated_cpus); - else - stop_machine(update_cpu_topology, &updates[0], &updated_cpus); - - /* - * Update the numa-cpu lookup table with the new mappings, even for - * offline CPUs. It is best to perform this update from the stop- - * machine context. - */ - if (cpus_locked) - stop_machine_cpuslocked(update_lookup_table, &updates[0], - cpumask_of(raw_smp_processor_id())); - else - stop_machine(update_lookup_table, &updates[0], - cpumask_of(raw_smp_processor_id())); - - for (ud = &updates[0]; ud; ud = ud->next) { - unregister_cpu_under_node(ud->cpu, ud->old_nid); - register_cpu_under_node(ud->cpu, ud->new_nid); - - dev = get_cpu_device(ud->cpu); - if (dev) - kobject_uevent(&dev->kobj, KOBJ_CHANGE); - cpumask_clear_cpu(ud->cpu, &cpu_associativity_changes_mask); - changed = 1; - } - -out: - kfree(updates); - return changed; + return 0; } int arch_update_cpu_topology(void) -- 2.25.4