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
|
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri, 14 Jun 2013 17:16:35 +0200
Subject: kernel/hotplug: restore original cpu mask oncpu/down
If a task which is allowed to run only on CPU X puts CPU Y down then it
will be allowed on all CPUs but the on CPU Y after it comes back from
kernel. This patch ensures that we don't lose the initial setting unless
the CPU the task is running is going down.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/cpu.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1088,6 +1088,7 @@ static int __ref _cpu_down(unsigned int
bool hasdied = false;
int mycpu;
cpumask_var_t cpumask;
+ cpumask_var_t cpumask_org;
if (num_online_cpus() == 1)
return -EBUSY;
@@ -1098,6 +1099,12 @@ static int __ref _cpu_down(unsigned int
/* Move the downtaker off the unplug cpu */
if (!alloc_cpumask_var(&cpumask, GFP_KERNEL))
return -ENOMEM;
+ if (!alloc_cpumask_var(&cpumask_org, GFP_KERNEL)) {
+ free_cpumask_var(cpumask);
+ return -ENOMEM;
+ }
+
+ cpumask_copy(cpumask_org, tsk_cpus_allowed(current));
cpumask_andnot(cpumask, cpu_online_mask, cpumask_of(cpu));
set_cpus_allowed_ptr(current, cpumask);
free_cpumask_var(cpumask);
@@ -1106,7 +1113,8 @@ static int __ref _cpu_down(unsigned int
if (mycpu == cpu) {
printk(KERN_ERR "Yuck! Still on unplug CPU\n!");
migrate_enable();
- return -EBUSY;
+ ret = -EBUSY;
+ goto restore_cpus;
}
cpu_hotplug_begin();
@@ -1160,6 +1168,9 @@ static int __ref _cpu_down(unsigned int
/* This post dead nonsense must die */
if (!ret && hasdied)
cpu_notify_nofail(CPU_POST_DEAD, cpu);
+restore_cpus:
+ set_cpus_allowed_ptr(current, cpumask_org);
+ free_cpumask_var(cpumask_org);
return ret;
}
|
