1 // SPDX-License-Identifier: GPL-2.0-only
3 * Housekeeping management. Manage the targets for routine code that can run on
4 * any CPU: unbound workqueues, timers, kthreads and any offloadable work.
6 * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
7 * Copyright (C) 2017-2018 SUSE, Frederic Weisbecker
12 DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
13 EXPORT_SYMBOL_GPL(housekeeping_overridden);
14 static cpumask_var_t housekeeping_mask;
15 static unsigned int housekeeping_flags;
17 bool housekeeping_enabled(enum hk_flags flags)
19 return !!(housekeeping_flags & flags);
21 EXPORT_SYMBOL_GPL(housekeeping_enabled);
23 int housekeeping_any_cpu(enum hk_flags flags)
27 if (static_branch_unlikely(&housekeeping_overridden)) {
28 if (housekeeping_flags & flags) {
29 cpu = sched_numa_find_closest(housekeeping_mask, smp_processor_id());
33 return cpumask_any_and(housekeeping_mask, cpu_online_mask);
36 return smp_processor_id();
38 EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
40 const struct cpumask *housekeeping_cpumask(enum hk_flags flags)
42 if (static_branch_unlikely(&housekeeping_overridden))
43 if (housekeeping_flags & flags)
44 return housekeeping_mask;
45 return cpu_possible_mask;
47 EXPORT_SYMBOL_GPL(housekeeping_cpumask);
49 void housekeeping_affine(struct task_struct *t, enum hk_flags flags)
51 if (static_branch_unlikely(&housekeeping_overridden))
52 if (housekeeping_flags & flags)
53 set_cpus_allowed_ptr(t, housekeeping_mask);
55 EXPORT_SYMBOL_GPL(housekeeping_affine);
57 bool housekeeping_test_cpu(int cpu, enum hk_flags flags)
59 if (static_branch_unlikely(&housekeeping_overridden))
60 if (housekeeping_flags & flags)
61 return cpumask_test_cpu(cpu, housekeeping_mask);
64 EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
66 void __init housekeeping_init(void)
68 if (!housekeeping_flags)
71 static_branch_enable(&housekeeping_overridden);
73 if (housekeeping_flags & HK_FLAG_TICK)
74 sched_tick_offload_init();
76 /* We need at least one CPU to handle housekeeping work */
77 WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
80 static int __init housekeeping_setup(char *str, enum hk_flags flags)
82 cpumask_var_t non_housekeeping_mask;
86 alloc_bootmem_cpumask_var(&non_housekeeping_mask);
87 err = cpulist_parse(str, non_housekeeping_mask);
88 if (err < 0 || cpumask_last(non_housekeeping_mask) >= nr_cpu_ids) {
89 pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n");
90 free_bootmem_cpumask_var(non_housekeeping_mask);
94 alloc_bootmem_cpumask_var(&tmp);
95 if (!housekeeping_flags) {
96 alloc_bootmem_cpumask_var(&housekeeping_mask);
97 cpumask_andnot(housekeeping_mask,
98 cpu_possible_mask, non_housekeeping_mask);
100 cpumask_andnot(tmp, cpu_present_mask, non_housekeeping_mask);
101 if (cpumask_empty(tmp)) {
102 pr_warn("Housekeeping: must include one present CPU, "
103 "using boot CPU:%d\n", smp_processor_id());
104 __cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
105 __cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
108 cpumask_andnot(tmp, cpu_present_mask, non_housekeeping_mask);
109 if (cpumask_empty(tmp))
110 __cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
111 cpumask_andnot(tmp, cpu_possible_mask, non_housekeeping_mask);
112 if (!cpumask_equal(tmp, housekeeping_mask)) {
113 pr_warn("Housekeeping: nohz_full= must match isolcpus=\n");
114 free_bootmem_cpumask_var(tmp);
115 free_bootmem_cpumask_var(non_housekeeping_mask);
119 free_bootmem_cpumask_var(tmp);
121 if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) {
122 if (IS_ENABLED(CONFIG_NO_HZ_FULL)) {
123 tick_nohz_full_setup(non_housekeeping_mask);
125 pr_warn("Housekeeping: nohz unsupported."
126 " Build with CONFIG_NO_HZ_FULL\n");
127 free_bootmem_cpumask_var(non_housekeeping_mask);
132 housekeeping_flags |= flags;
134 free_bootmem_cpumask_var(non_housekeeping_mask);
139 static int __init housekeeping_nohz_full_setup(char *str)
143 flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU |
144 HK_FLAG_MISC | HK_FLAG_KTHREAD;
146 return housekeeping_setup(str, flags);
148 __setup("nohz_full=", housekeeping_nohz_full_setup);
150 static int __init housekeeping_isolcpus_setup(char *str)
152 unsigned int flags = 0;
153 bool illegal = false;
157 while (isalpha(*str)) {
158 if (!strncmp(str, "nohz,", 5)) {
160 flags |= HK_FLAG_TICK;
164 if (!strncmp(str, "domain,", 7)) {
166 flags |= HK_FLAG_DOMAIN;
170 if (!strncmp(str, "managed_irq,", 12)) {
172 flags |= HK_FLAG_MANAGED_IRQ;
177 * Skip unknown sub-parameter and validate that it is not
178 * containing an invalid character.
180 for (par = str, len = 0; *str && *str != ','; str++, len++) {
181 if (!isalpha(*str) && *str != '_')
186 pr_warn("isolcpus: Invalid flag %.*s\n", len, par);
190 pr_info("isolcpus: Skipped unknown flag %.*s\n", len, par);
194 /* Default behaviour for isolcpus without flags */
196 flags |= HK_FLAG_DOMAIN;
198 return housekeeping_setup(str, flags);
200 __setup("isolcpus=", housekeeping_isolcpus_setup);