Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'cpumask-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus
* 'cpumask-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
cpumask: rename tsk_cpumask to tsk_cpus_allowed
cpumask: don't recommend set_cpus_allowed hack in Documentation/cpu-hotplug.txt
cpumask: avoid dereferencing struct cpumask
cpumask: convert drivers/idle/i7300_idle.c to cpumask_var_t
cpumask: use modern cpumask style in drivers/scsi/fcoe/fcoe.c
cpumask: avoid deprecated function in mm/slab.c
cpumask: use cpu_online in kernel/perf_event.c
+33
-45
+17
-32
Documentation/cpu-hotplug.txt
+17
-32
Documentation/cpu-hotplug.txt
···
315
315
316
316
Q: I need to ensure that a particular cpu is not removed when there is some
317
317
work specific to this cpu is in progress.
318
-
A: First switch the current thread context to preferred cpu
318
+
A: There are two ways. If your code can be run in interrupt context, use
319
+
smp_call_function_single(), otherwise use work_on_cpu(). Note that
320
+
work_on_cpu() is slow, and can fail due to out of memory:
319
321
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322
int my_func_on_cpu(int cpu)
321
323
{
322
-
cpumask_t saved_mask, new_mask = CPU_MASK_NONE;
323
-
int curr_cpu, err = 0;
324
-
325
-
saved_mask = current->cpus_allowed;
326
-
cpu_set(cpu, new_mask);
327
-
err = set_cpus_allowed(current, new_mask);
328
-
329
-
if (err)
330
-
return err;
331
-
332
-
/*
333
-
* If we got scheduled out just after the return from
334
-
* set_cpus_allowed() before running the work, this ensures
335
-
* we stay locked.
336
-
*/
337
-
curr_cpu = get_cpu();
338
-
339
-
if (curr_cpu != cpu) {
340
-
err = -EAGAIN;
341
-
goto ret;
342
-
} else {
343
-
/*
344
-
* Do work : But cant sleep, since get_cpu() disables preempt
345
-
*/
346
-
}
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-
ret:
348
-
put_cpu();
349
-
set_cpus_allowed(current, saved_mask);
350
-
return err;
351
-
}
352
-
324
+
int err;
325
+
get_online_cpus();
326
+
if (!cpu_online(cpu))
327
+
err = -EINVAL;
328
+
else
329
+
#if NEEDS_BLOCKING
330
+
err = work_on_cpu(cpu, __my_func_on_cpu, NULL);
331
+
#else
332
+
smp_call_function_single(cpu, __my_func_on_cpu, &err,
333
+
true);
334
+
#endif
335
+
put_online_cpus();
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+
return err;
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+
}
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339
Q: How do we determine how many CPUs are available for hotplug.
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340
A: There is no clear spec defined way from ACPI that can give us that
+1
-1
arch/x86/kernel/cpu/cpufreq/powernow-k8.c
+1
-1
arch/x86/kernel/cpu/cpufreq/powernow-k8.c
···
1136
1136
if (!alloc_cpumask_var(&oldmask, GFP_KERNEL))
1137
1137
return -ENOMEM;
1138
1138
1139
-
cpumask_copy(oldmask, tsk_cpumask(current));
1139
+
cpumask_copy(oldmask, tsk_cpus_allowed(current));
1140
1140
set_cpus_allowed_ptr(current, cpumask_of(pol->cpu));
1141
1141
1142
1142
if (smp_processor_id() != pol->cpu) {
+9
-6
drivers/idle/i7300_idle.c
+9
-6
drivers/idle/i7300_idle.c
···
81
81
static u8 i7300_idle_thrtlow_saved;
82
82
static u32 i7300_idle_mc_saved;
83
83
84
-
static cpumask_t idle_cpumask;
84
+
static cpumask_var_t idle_cpumask;
85
85
static ktime_t start_ktime;
86
86
static unsigned long avg_idle_us;
87
87
···
459
459
spin_lock_irqsave(&i7300_idle_lock, flags);
460
460
if (val == IDLE_START) {
461
461
462
-
cpu_set(smp_processor_id(), idle_cpumask);
462
+
cpumask_set_cpu(smp_processor_id(), idle_cpumask);
463
463
464
-
if (cpus_weight(idle_cpumask) != num_online_cpus())
464
+
if (cpumask_weight(idle_cpumask) != num_online_cpus())
465
465
goto end;
466
466
467
467
now_ktime = ktime_get();
···
478
478
i7300_idle_ioat_start();
479
479
480
480
} else if (val == IDLE_END) {
481
-
cpu_clear(smp_processor_id(), idle_cpumask);
482
-
if (cpus_weight(idle_cpumask) == (num_online_cpus() - 1)) {
481
+
cpumask_clear_cpu(smp_processor_id(), idle_cpumask);
482
+
if (cpumask_weight(idle_cpumask) == (num_online_cpus() - 1)) {
483
483
/* First CPU coming out of idle */
484
484
u64 idle_duration_us;
485
485
···
553
553
static int __init i7300_idle_init(void)
554
554
{
555
555
spin_lock_init(&i7300_idle_lock);
556
-
cpus_clear(idle_cpumask);
557
556
total_us = 0;
558
557
559
558
if (i7300_idle_platform_probe(&fbd_dev, &ioat_dev, forceload))
···
563
564
564
565
if (i7300_idle_ioat_init())
565
566
return -ENODEV;
567
+
568
+
if (!zalloc_cpumask_var(&idle_cpumask, GFP_KERNEL))
569
+
return -ENOMEM;
566
570
567
571
debugfs_dir = debugfs_create_dir("i7300_idle", NULL);
568
572
if (debugfs_dir) {
···
591
589
static void __exit i7300_idle_exit(void)
592
590
{
593
591
idle_notifier_unregister(&i7300_idle_nb);
592
+
free_cpumask_var(idle_cpumask);
594
593
595
594
if (debugfs_dir) {
596
595
int i = 0;
+1
-1
drivers/scsi/fcoe/fcoe.c
+1
-1
drivers/scsi/fcoe/fcoe.c
+1
-1
include/linux/sched.h
+1
-1
include/linux/sched.h
···
1553
1553
};
1554
1554
1555
1555
/* Future-safe accessor for struct task_struct's cpus_allowed. */
1556
-
#define tsk_cpumask(tsk) (&(tsk)->cpus_allowed)
1556
+
#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
1557
1557
1558
1558
/*
1559
1559
* Priority of a process goes from 0..MAX_PRIO-1, valid RT
+1
-1
kernel/perf_event.c
+1
-1
kernel/perf_event.c
+2
-2
kernel/time/timer_list.c
+2
-2
kernel/time/timer_list.c
···
237
237
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
238
238
print_tickdevice(m, tick_get_broadcast_device(), -1);
239
239
SEQ_printf(m, "tick_broadcast_mask: %08lx\n",
240
-
tick_get_broadcast_mask()->bits[0]);
240
+
cpumask_bits(tick_get_broadcast_mask())[0]);
241
241
#ifdef CONFIG_TICK_ONESHOT
242
242
SEQ_printf(m, "tick_broadcast_oneshot_mask: %08lx\n",
243
-
tick_get_broadcast_oneshot_mask()->bits[0]);
243
+
cpumask_bits(tick_get_broadcast_oneshot_mask())[0]);
244
244
#endif
245
245
SEQ_printf(m, "\n");
246
246
#endif