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
|
#ifndef _LINUX_STOP_MACHINE
#define _LINUX_STOP_MACHINE
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/list.h>
#include <asm/system.h>
#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
/*
* stop_cpu[s]() is simplistic per-cpu maximum priority cpu
* monopolization mechanism. The caller can specify a non-sleeping
* function to be executed on a single or multiple cpus preempting all
* other processes and monopolizing those cpus until it finishes.
*
* Resources for this mechanism are preallocated when a cpu is brought
* up and requests are guaranteed to be served as long as the target
* cpus are online.
*/
typedef int (*cpu_stop_fn_t)(void *arg);
struct cpu_stop_work {
struct list_head list; /* cpu_stopper->works */
cpu_stop_fn_t fn;
void *arg;
struct cpu_stop_done *done;
};
int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg);
void stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
struct cpu_stop_work *work_buf);
int stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);
int try_stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);
/*
* stop_machine "Bogolock": stop the entire machine, disable
* interrupts. This is a very heavy lock, which is equivalent to
* grabbing every spinlock (and more). So the "read" side to such a
* lock is anything which disables preeempt.
*/
/**
* stop_machine: freeze the machine on all CPUs and run this function
* @fn: the function to run
* @data: the data ptr for the @fn()
* @cpus: the cpus to run the @fn() on (NULL = any online cpu)
*
* Description: This causes a thread to be scheduled on every cpu,
* each of which disables interrupts. The result is that noone is
* holding a spinlock or inside any other preempt-disabled region when
* @fn() runs.
*
* This can be thought of as a very heavy write lock, equivalent to
* grabbing every spinlock in the kernel. */
int stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus);
/**
* __stop_machine: freeze the machine on all CPUs and run this function
* @fn: the function to run
* @data: the data ptr for the @fn
* @cpus: the cpus to run the @fn() on (NULL = any online cpu)
*
* Description: This is a special version of the above, which assumes cpus
* won't come or go while it's being called. Used by hotplug cpu.
*/
int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus);
#else
static inline int stop_machine(int (*fn)(void *), void *data,
const struct cpumask *cpus)
{
int ret;
local_irq_disable();
ret = fn(data);
local_irq_enable();
return ret;
}
#endif /* CONFIG_SMP */
#endif /* _LINUX_STOP_MACHINE */
|
