forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
isolation.c
176 lines (147 loc) · 4.71 KB
/
isolation.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
// SPDX-License-Identifier: GPL-2.0-only
/*
* Housekeeping management. Manage the targets for routine code that can run on
* any CPU: unbound workqueues, timers, kthreads and any offloadable work.
*
* Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
* Copyright (C) 2017-2018 SUSE, Frederic Weisbecker
*
*/
#include "sched.h"
DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
EXPORT_SYMBOL_GPL(housekeeping_overridden);
static cpumask_var_t housekeeping_mask;
static unsigned int housekeeping_flags;
bool housekeeping_enabled(enum hk_flags flags)
{
return !!(housekeeping_flags & flags);
}
EXPORT_SYMBOL_GPL(housekeeping_enabled);
int housekeeping_any_cpu(enum hk_flags flags)
{
int cpu;
if (static_branch_unlikely(&housekeeping_overridden)) {
if (housekeeping_flags & flags) {
cpu = sched_numa_find_closest(housekeeping_mask, smp_processor_id());
if (cpu < nr_cpu_ids)
return cpu;
return cpumask_any_and(housekeeping_mask, cpu_online_mask);
}
}
return smp_processor_id();
}
EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
const struct cpumask *housekeeping_cpumask(enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overridden))
if (housekeeping_flags & flags)
return housekeeping_mask;
return cpu_possible_mask;
}
EXPORT_SYMBOL_GPL(housekeeping_cpumask);
void housekeeping_affine(struct task_struct *t, enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overridden))
if (housekeeping_flags & flags)
set_cpus_allowed_ptr(t, housekeeping_mask);
}
EXPORT_SYMBOL_GPL(housekeeping_affine);
bool housekeeping_test_cpu(int cpu, enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overridden))
if (housekeeping_flags & flags)
return cpumask_test_cpu(cpu, housekeeping_mask);
return true;
}
EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
void __init housekeeping_init(void)
{
if (!housekeeping_flags)
return;
static_branch_enable(&housekeeping_overridden);
if (housekeeping_flags & HK_FLAG_TICK)
sched_tick_offload_init();
/* We need at least one CPU to handle housekeeping work */
WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
}
static int __init housekeeping_setup(char *str, enum hk_flags flags)
{
cpumask_var_t non_housekeeping_mask;
cpumask_var_t tmp;
int err;
alloc_bootmem_cpumask_var(&non_housekeeping_mask);
err = cpulist_parse(str, non_housekeeping_mask);
if (err < 0 || cpumask_last(non_housekeeping_mask) >= nr_cpu_ids) {
pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n");
free_bootmem_cpumask_var(non_housekeeping_mask);
return 0;
}
alloc_bootmem_cpumask_var(&tmp);
if (!housekeeping_flags) {
alloc_bootmem_cpumask_var(&housekeeping_mask);
cpumask_andnot(housekeeping_mask,
cpu_possible_mask, non_housekeeping_mask);
cpumask_andnot(tmp, cpu_present_mask, non_housekeeping_mask);
if (cpumask_empty(tmp)) {
pr_warn("Housekeeping: must include one present CPU, "
"using boot CPU:%d\n", smp_processor_id());
__cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
__cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
}
} else {
cpumask_andnot(tmp, cpu_present_mask, non_housekeeping_mask);
if (cpumask_empty(tmp))
__cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
cpumask_andnot(tmp, cpu_possible_mask, non_housekeeping_mask);
if (!cpumask_equal(tmp, housekeeping_mask)) {
pr_warn("Housekeeping: nohz_full= must match isolcpus=\n");
free_bootmem_cpumask_var(tmp);
free_bootmem_cpumask_var(non_housekeeping_mask);
return 0;
}
}
free_bootmem_cpumask_var(tmp);
if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) {
if (IS_ENABLED(CONFIG_NO_HZ_FULL)) {
tick_nohz_full_setup(non_housekeeping_mask);
} else {
pr_warn("Housekeeping: nohz unsupported."
" Build with CONFIG_NO_HZ_FULL\n");
free_bootmem_cpumask_var(non_housekeeping_mask);
return 0;
}
}
housekeeping_flags |= flags;
free_bootmem_cpumask_var(non_housekeeping_mask);
return 1;
}
static int __init housekeeping_nohz_full_setup(char *str)
{
unsigned int flags;
flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC;
return housekeeping_setup(str, flags);
}
__setup("nohz_full=", housekeeping_nohz_full_setup);
static int __init housekeeping_isolcpus_setup(char *str)
{
unsigned int flags = 0;
while (isalpha(*str)) {
if (!strncmp(str, "nohz,", 5)) {
str += 5;
flags |= HK_FLAG_TICK;
continue;
}
if (!strncmp(str, "domain,", 7)) {
str += 7;
flags |= HK_FLAG_DOMAIN;
continue;
}
pr_warn("isolcpus: Error, unknown flag\n");
return 0;
}
/* Default behaviour for isolcpus without flags */
if (!flags)
flags |= HK_FLAG_DOMAIN;
return housekeeping_setup(str, flags);
}
__setup("isolcpus=", housekeeping_isolcpus_setup);