diff options
| -rw-r--r-- | include/linux/interrupt.h | 8 | ||||
| -rw-r--r-- | kernel/irq/Makefile | 1 | ||||
| -rw-r--r-- | kernel/irq/affinity.c | 61 |
3 files changed, 70 insertions, 0 deletions
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 9fcabeb07787..b6683f0ffc9f 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -278,6 +278,8 @@ extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m); extern int irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify); +struct cpumask *irq_create_affinity_mask(unsigned int *nr_vecs); + #else /* CONFIG_SMP */ static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m) @@ -308,6 +310,12 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify) { return 0; } + +static inline struct cpumask *irq_create_affinity_mask(unsigned int *nr_vecs) +{ + *nr_vecs = 1; + return NULL; +} #endif /* CONFIG_SMP */ /* diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile index 2ee42e95a3ce..1d3ee3169202 100644 --- a/kernel/irq/Makefile +++ b/kernel/irq/Makefile @@ -9,3 +9,4 @@ obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o obj-$(CONFIG_PM_SLEEP) += pm.o obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o obj-$(CONFIG_GENERIC_IRQ_IPI) += ipi.o +obj-$(CONFIG_SMP) += affinity.o diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c new file mode 100644 index 000000000000..f68959341c0f --- /dev/null +++ b/kernel/irq/affinity.c @@ -0,0 +1,61 @@ + +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/cpu.h> + +static int get_first_sibling(unsigned int cpu) +{ + unsigned int ret; + + ret = cpumask_first(topology_sibling_cpumask(cpu)); + if (ret < nr_cpu_ids) + return ret; + return cpu; +} + +/* + * Take a map of online CPUs and the number of available interrupt vectors + * and generate an output cpumask suitable for spreading MSI/MSI-X vectors + * so that they are distributed as good as possible around the CPUs. If + * more vectors than CPUs are available we'll map one to each CPU, + * otherwise we map one to the first sibling of each socket. + * + * If there are more vectors than CPUs we will still only have one bit + * set per CPU, but interrupt code will keep on assigning the vectors from + * the start of the bitmap until we run out of vectors. + */ +struct cpumask *irq_create_affinity_mask(unsigned int *nr_vecs) +{ + struct cpumask *affinity_mask; + unsigned int max_vecs = *nr_vecs; + + if (max_vecs == 1) + return NULL; + + affinity_mask = kzalloc(cpumask_size(), GFP_KERNEL); + if (!affinity_mask) { + *nr_vecs = 1; + return NULL; + } + + if (max_vecs >= num_online_cpus()) { + cpumask_copy(affinity_mask, cpu_online_mask); + *nr_vecs = num_online_cpus(); + } else { + unsigned int vecs = 0, cpu; + + for_each_online_cpu(cpu) { + if (cpu == get_first_sibling(cpu)) { + cpumask_set_cpu(cpu, affinity_mask); + vecs++; + } + + if (--max_vecs == 0) + break; + } + *nr_vecs = vecs; + } + + return affinity_mask; +} |