[PATCH 3/4] generic-smp: properly allocate the cpumasks

Peter Zijlstra
2009-02-16T16:42:38Z

[-- Attachment #1: smp-proper-cpu-mask.patch --]
[-- Type: text/plain, Size: 3694 bytes --]

Its not deemed proper to have full cpumasks in data anymore, we have to
dynamically allocate them based on runtime determined dimensions of the
machine in question.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
kernel/smp.c | 54 +++++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 45 insertions(+), 9 deletions(-)

Index: linux-2.6/kernel/smp.c
===================================================================
--- linux-2.6.orig/kernel/smp.c
+++ linux-2.6/kernel/smp.c
@@ -10,6 +10,7 @@
#include <linux/rcupdate.h>
#include <linux/rculist.h>
#include <linux/smp.h>
+#include <linux/cpu.h>

static DEFINE_PER_CPU(struct call_single_queue, call_single_queue);

@@ -40,7 +41,7 @@ struct call_function_data {
spinlock_t lock;
unsigned int refs;
struct list_head free_list;
- struct cpumask cpumask;
+ cpumask_var_t cpumask;
};

struct call_single_queue {
@@ -48,8 +49,41 @@ struct call_single_queue {
spinlock_t lock;
};

+static DEFINE_PER_CPU(struct call_function_data, cfd_data);
+
+static int
+hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+ long cpu = (long)hcpu;
+ struct call_function_data *cfd = &per_cpu(cfd_data, cpu);
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ if (!alloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
+ cpu_to_node(cpu)))
+ return NOTIFY_BAD;
+ break;
+
+ case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_FROZEN:
+
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ free_cpumask_var(cfd->cpumask);
+ break;
+ };
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata hotplug_cfd_notifier = {
+ .notifier_call = hotplug_cfd,
+};
+
static int __cpuinit init_call_single_data(void)
{
+ void *cpu = (void *)(long)smp_processor_id();
int i;

for_each_possible_cpu(i) {
@@ -58,6 +92,10 @@ static int __cpuinit init_call_single_da
spin_lock_init(&q->lock);
INIT_LIST_HEAD(&q->list);
}
+
+ hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu);
+ register_cpu_notifier(&hotplug_cfd_notifier);
+
return 0;
}
early_initcall(init_call_single_data);
@@ -116,13 +154,13 @@ void generic_smp_call_function_interrupt
LIST_HEAD(free_list);
int refs;

- if (!cpumask_test_cpu(cpu, &data->cpumask))
+ if (!cpumask_test_cpu(cpu, data->cpumask))
continue;

data->csd.func(data->csd.info);

spin_lock(&data->lock);
- cpumask_clear_cpu(cpu, &data->cpumask);
+ cpumask_clear_cpu(cpu, data->cpumask);
WARN_ON(data->refs == 0);
data->refs--;
refs = data->refs;
@@ -313,8 +351,6 @@ void __smp_call_function_single(int cpu,
arch_send_call_function_ipi(*(maskp))
#endif

-static DEFINE_PER_CPU(struct call_function_data, cfd_data);
-
/**
* smp_call_function_many(): Run a function on a set of other CPUs.
* @mask: The set of cpus to run on (only runs on online subset).
@@ -373,9 +409,9 @@ void smp_call_function_many(const struct
data->csd.flags |= CSD_FLAG_WAIT;
data->csd.func = func;
data->csd.info = info;
- cpumask_and(&data->cpumask, mask, cpu_online_mask);
- cpumask_clear_cpu(smp_processor_id(), &data->cpumask);
- data->refs = cpumask_weight(&data->cpumask);
+ cpumask_and(data->cpumask, mask, cpu_online_mask);
+ cpumask_clear_cpu(smp_processor_id(), data->cpumask);
+ data->refs = cpumask_weight(data->cpumask);

spin_lock_irqsave(&call_function.lock, flags);
call_function.counter++;
@@ -388,7 +424,7 @@ void smp_call_function_many(const struct
smp_mb();

/* Send a message to all CPUs in the map */
- arch_send_call_function_ipi_mask(&data->cpumask);
+ arch_send_call_function_ipi_mask(data->cpumask);

/* optionally wait for the CPUs to complete */
if (wait)

--