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Commit | Line | Data |
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78634061 FW |
1 | /* |
2 | * Housekeeping management. Manage the targets for routine code that can run on | |
3 | * any CPU: unbound workqueues, timers, kthreads and any offloadable work. | |
4 | * | |
5 | * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker | |
6 | * | |
7 | */ | |
8 | ||
9 | #include <linux/sched/isolation.h> | |
10 | #include <linux/tick.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/kernel.h> | |
e179f5a0 | 13 | #include <linux/static_key.h> |
150dfee9 | 14 | #include <linux/ctype.h> |
78634061 | 15 | |
e179f5a0 FW |
16 | DEFINE_STATIC_KEY_FALSE(housekeeping_overriden); |
17 | EXPORT_SYMBOL_GPL(housekeeping_overriden); | |
7e56a1cf | 18 | static cpumask_var_t housekeeping_mask; |
de201559 | 19 | static unsigned int housekeeping_flags; |
7e56a1cf | 20 | |
de201559 | 21 | int housekeeping_any_cpu(enum hk_flags flags) |
7e56a1cf | 22 | { |
e179f5a0 | 23 | if (static_branch_unlikely(&housekeeping_overriden)) |
de201559 FW |
24 | if (housekeeping_flags & flags) |
25 | return cpumask_any_and(housekeeping_mask, cpu_online_mask); | |
7e56a1cf FW |
26 | return smp_processor_id(); |
27 | } | |
28 | EXPORT_SYMBOL_GPL(housekeeping_any_cpu); | |
29 | ||
de201559 | 30 | const struct cpumask *housekeeping_cpumask(enum hk_flags flags) |
7e56a1cf | 31 | { |
e179f5a0 | 32 | if (static_branch_unlikely(&housekeeping_overriden)) |
de201559 FW |
33 | if (housekeeping_flags & flags) |
34 | return housekeeping_mask; | |
7e56a1cf FW |
35 | return cpu_possible_mask; |
36 | } | |
37 | EXPORT_SYMBOL_GPL(housekeeping_cpumask); | |
38 | ||
de201559 | 39 | void housekeeping_affine(struct task_struct *t, enum hk_flags flags) |
7e56a1cf | 40 | { |
e179f5a0 | 41 | if (static_branch_unlikely(&housekeeping_overriden)) |
de201559 FW |
42 | if (housekeeping_flags & flags) |
43 | set_cpus_allowed_ptr(t, housekeeping_mask); | |
7e56a1cf FW |
44 | } |
45 | EXPORT_SYMBOL_GPL(housekeeping_affine); | |
46 | ||
de201559 | 47 | bool housekeeping_test_cpu(int cpu, enum hk_flags flags) |
7e56a1cf | 48 | { |
e179f5a0 | 49 | if (static_branch_unlikely(&housekeeping_overriden)) |
de201559 FW |
50 | if (housekeeping_flags & flags) |
51 | return cpumask_test_cpu(cpu, housekeeping_mask); | |
7e56a1cf FW |
52 | return true; |
53 | } | |
54 | EXPORT_SYMBOL_GPL(housekeeping_test_cpu); | |
78634061 FW |
55 | |
56 | void __init housekeeping_init(void) | |
57 | { | |
6f1982fe | 58 | if (!housekeeping_flags) |
78634061 FW |
59 | return; |
60 | ||
6f1982fe FW |
61 | static_branch_enable(&housekeeping_overriden); |
62 | ||
63 | /* We need at least one CPU to handle housekeeping work */ | |
64 | WARN_ON_ONCE(cpumask_empty(housekeeping_mask)); | |
65 | } | |
66 | ||
edb93821 | 67 | static int __init housekeeping_setup(char *str, enum hk_flags flags) |
6f1982fe FW |
68 | { |
69 | cpumask_var_t non_housekeeping_mask; | |
edb93821 | 70 | int err; |
6f1982fe FW |
71 | |
72 | alloc_bootmem_cpumask_var(&non_housekeeping_mask); | |
edb93821 FW |
73 | err = cpulist_parse(str, non_housekeeping_mask); |
74 | if (err < 0 || cpumask_last(non_housekeeping_mask) >= nr_cpu_ids) { | |
75 | pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n"); | |
6f1982fe FW |
76 | free_bootmem_cpumask_var(non_housekeeping_mask); |
77 | return 0; | |
78634061 FW |
78 | } |
79 | ||
edb93821 FW |
80 | if (!housekeeping_flags) { |
81 | alloc_bootmem_cpumask_var(&housekeeping_mask); | |
82 | cpumask_andnot(housekeeping_mask, | |
83 | cpu_possible_mask, non_housekeeping_mask); | |
84 | if (cpumask_empty(housekeeping_mask)) | |
85 | cpumask_set_cpu(smp_processor_id(), housekeeping_mask); | |
86 | } else { | |
87 | cpumask_var_t tmp; | |
88 | ||
89 | alloc_bootmem_cpumask_var(&tmp); | |
90 | cpumask_andnot(tmp, cpu_possible_mask, non_housekeeping_mask); | |
91 | if (!cpumask_equal(tmp, housekeeping_mask)) { | |
92 | pr_warn("Housekeeping: nohz_full= must match isolcpus=\n"); | |
93 | free_bootmem_cpumask_var(tmp); | |
94 | free_bootmem_cpumask_var(non_housekeeping_mask); | |
95 | return 0; | |
96 | } | |
97 | free_bootmem_cpumask_var(tmp); | |
98 | } | |
de201559 | 99 | |
edb93821 FW |
100 | if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) { |
101 | if (IS_ENABLED(CONFIG_NO_HZ_FULL)) { | |
102 | tick_nohz_full_setup(non_housekeeping_mask); | |
103 | } else { | |
104 | pr_warn("Housekeeping: nohz unsupported." | |
105 | " Build with CONFIG_NO_HZ_FULL\n"); | |
106 | free_bootmem_cpumask_var(non_housekeeping_mask); | |
107 | return 0; | |
108 | } | |
109 | } | |
e179f5a0 | 110 | |
edb93821 | 111 | housekeeping_flags |= flags; |
6f1982fe FW |
112 | |
113 | free_bootmem_cpumask_var(non_housekeeping_mask); | |
114 | ||
115 | return 1; | |
78634061 | 116 | } |
edb93821 FW |
117 | |
118 | static int __init housekeeping_nohz_full_setup(char *str) | |
119 | { | |
120 | unsigned int flags; | |
121 | ||
122 | flags = HK_FLAG_TICK | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC; | |
123 | ||
124 | return housekeeping_setup(str, flags); | |
125 | } | |
6f1982fe | 126 | __setup("nohz_full=", housekeeping_nohz_full_setup); |
edb93821 FW |
127 | |
128 | static int __init housekeeping_isolcpus_setup(char *str) | |
129 | { | |
150dfee9 FW |
130 | unsigned int flags = 0; |
131 | ||
132 | while (isalpha(*str)) { | |
133 | if (!strncmp(str, "nohz,", 5)) { | |
134 | str += 5; | |
135 | flags |= HK_FLAG_TICK; | |
136 | continue; | |
137 | } | |
138 | ||
139 | if (!strncmp(str, "domain,", 7)) { | |
140 | str += 7; | |
141 | flags |= HK_FLAG_DOMAIN; | |
142 | continue; | |
143 | } | |
144 | ||
145 | pr_warn("isolcpus: Error, unknown flag\n"); | |
146 | return 0; | |
147 | } | |
148 | ||
149 | /* Default behaviour for isolcpus without flags */ | |
150 | if (!flags) | |
151 | flags |= HK_FLAG_DOMAIN; | |
152 | ||
153 | return housekeeping_setup(str, flags); | |
edb93821 FW |
154 | } |
155 | __setup("isolcpus=", housekeeping_isolcpus_setup); |