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
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
/*
* General MIPS MT support routines, usable in AP/SP and SMVP.
* Copyright (C) 2005 Mips Technologies, Inc
*/
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/cpumask.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/security.h>
#include <linux/types.h>
#include <linux/uaccess.h>
/*
* CPU mask used to set process affinity for MT VPEs/TCs with FPUs
*/
cpumask_t mt_fpu_cpumask;
static int fpaff_threshold = -1;
unsigned long mt_fpemul_threshold;
/*
* Replacement functions for the sys_sched_setaffinity() and
* sys_sched_getaffinity() system calls, so that we can integrate
* FPU affinity with the user's requested processor affinity.
* This code is 98% identical with the sys_sched_setaffinity()
* and sys_sched_getaffinity() system calls, and should be
* updated when kernel/sched/core.c changes.
*/
/*
* find_process_by_pid - find a process with a matching PID value.
* used in sys_sched_set/getaffinity() in kernel/sched/core.c, so
* cloned here.
*/
static inline struct task_struct *find_process_by_pid(pid_t pid)
{
return pid ? find_task_by_vpid(pid) : current;
}
/*
* check the target process has a UID that matches the current process's
*/
static bool check_same_owner(struct task_struct *p)
{
const struct cred *cred = current_cred(), *pcred;
bool match;
rcu_read_lock();
pcred = __task_cred(p);
match = (uid_eq(cred->euid, pcred->euid) ||
uid_eq(cred->euid, pcred->uid));
rcu_read_unlock();
return match;
}
/*
* mipsmt_sys_sched_setaffinity - set the cpu affinity of a process
*/
asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len,
unsigned long __user *user_mask_ptr)
{
cpumask_var_t cpus_allowed, new_mask, effective_mask;
struct thread_info *ti;
struct task_struct *p;
int retval;
if (len < sizeof(new_mask))
return -EINVAL;
if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask)))
return -EFAULT;
get_online_cpus();
rcu_read_lock();
p = find_process_by_pid(pid);
if (!p) {
rcu_read_unlock();
put_online_cpus();
return -ESRCH;
}
/* Prevent p going away */
get_task_struct(p);
rcu_read_unlock();
if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
retval = -ENOMEM;
goto out_put_task;
}
if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
retval = -ENOMEM;
goto out_free_cpus_allowed;
}
if (!alloc_cpumask_var(&effective_mask, GFP_KERNEL)) {
retval = -ENOMEM;
goto out_free_new_mask;
}
retval = -EPERM;
if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
goto out_unlock;
retval = security_task_setscheduler(p);
if (retval)
goto out_unlock;
/* Record new user-specified CPU set for future reference */
cpumask_copy(&p->thread.user_cpus_allowed, new_mask);
again:
/* Compute new global allowed CPU set if necessary */
ti = task_thread_info(p);
if (test_ti_thread_flag(ti, TIF_FPUBOUND) &&
cpumask_intersects(new_mask, &mt_fpu_cpumask)) {
cpumask_and(effective_mask, new_mask, &mt_fpu_cpumask);
retval = set_cpus_allowed_ptr(p, effective_mask);
} else {
cpumask_copy(effective_mask, new_mask);
clear_ti_thread_flag(ti, TIF_FPUBOUND);
retval = set_cpus_allowed_ptr(p, new_mask);
}
if (!retval) {
cpuset_cpus_allowed(p, cpus_allowed);
if (!cpumask_subset(effective_mask, cpus_allowed)) {
/*
* We must have raced with a concurrent cpuset
* update. Just reset the cpus_allowed to the
* cpuset's cpus_allowed
*/
cpumask_copy(new_mask, cpus_allowed);
goto again;
}
}
out_unlock:
free_cpumask_var(effective_mask);
out_free_new_mask:
free_cpumask_var(new_mask);
out_free_cpus_allowed:
free_cpumask_var(cpus_allowed);
out_put_task:
put_task_struct(p);
put_online_cpus();
return retval;
}
/*
* mipsmt_sys_sched_getaffinity - get the cpu affinity of a process
*/
asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len,
unsigned long __user *user_mask_ptr)
{
unsigned int real_len;
cpumask_t allowed, mask;
int retval;
struct task_struct *p;
real_len = sizeof(mask);
if (len < real_len)
return -EINVAL;
get_online_cpus();
read_lock(&tasklist_lock);
retval = -ESRCH;
p = find_process_by_pid(pid);
if (!p)
goto out_unlock;
retval = security_task_getscheduler(p);
if (retval)
goto out_unlock;
cpumask_or(&allowed, &p->thread.user_cpus_allowed, &p->cpus_allowed);
cpumask_and(&mask, &allowed, cpu_active_mask);
out_unlock:
read_unlock(&tasklist_lock);
put_online_cpus();
if (retval)
return retval;
if (copy_to_user(user_mask_ptr, &mask, real_len))
return -EFAULT;
return real_len;
}
static int __init fpaff_thresh(char *str)
{
get_option(&str, &fpaff_threshold);
return 1;
}
__setup("fpaff=", fpaff_thresh);
/*
* FPU Use Factor empirically derived from experiments on 34K
*/
#define FPUSEFACTOR 2000
static __init int mt_fp_affinity_init(void)
{
if (fpaff_threshold >= 0) {
mt_fpemul_threshold = fpaff_threshold;
} else {
mt_fpemul_threshold =
(FPUSEFACTOR * (loops_per_jiffy/(500000/HZ))) / HZ;
}
printk(KERN_DEBUG "FPU Affinity set after %ld emulations\n",
mt_fpemul_threshold);
return 0;
}
arch_initcall(mt_fp_affinity_init);
|
