Re: [PATCH V5 6/9] MIPS: Loongson-3: support irq_set_affinity() in i8259 chip

[Ralf Baechle]

On Thu, Jun 15, 2017 at 10:31:05AM +0800, Huacai Chen wrote:

> With this patch we can set irq affinity via procfs, so as to improve
> network performance.
>
> Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
> ---
>  arch/mips/include/asm/irq.h           |  3 ++
>  arch/mips/loongson64/loongson-3/irq.c | 62 +++++++++++++++++++++++++++--------
>  drivers/irqchip/irq-i8259.c           |  3 ++
>  3 files changed, 55 insertions(+), 13 deletions(-)

You didn't cc the IRQCHIP maintainers:

IRQCHIP DRIVERS
M:      Thomas Gleixner <tglx@xxxxxxxxxxxxx>
M:      Jason Cooper <jason@xxxxxxxxxxxxxx>
M:      Marc Zyngier <marc.zyngier@xxxxxxx>
L:      linux-kernel@xxxxxxxxxxxxxxx
S:      Maintained
T:      git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq/core
T:      git git://git.infradead.org/users/jcooper/linux.git irqchip/core
F:      Documentation/devicetree/bindings/interrupt-controller/
F:      drivers/irqchip/

  Ralf


> diff --git a/arch/mips/include/asm/irq.h b/arch/mips/include/asm/irq.h
> index ddd1c91..47ff7c6 100644
> --- a/arch/mips/include/asm/irq.h
> +++ b/arch/mips/include/asm/irq.h
> @@ -53,6 +53,7 @@ static inline int irq_canonicalize(int irq)
>  #define irq_canonicalize(irq) (irq)	/* Sane hardware, sane code ... */
>  #endif
>  
> +struct irq_data;
>  asmlinkage void plat_irq_dispatch(void);
>  
>  extern void do_IRQ(unsigned int irq);
> @@ -63,6 +64,8 @@ extern void spurious_interrupt(void);
>  extern int allocate_irqno(void);
>  extern void alloc_legacy_irqno(void);
>  extern void free_irqno(unsigned int irq);
> +extern int plat_set_irq_affinity(struct irq_data *d,
> +				 const struct cpumask *affinity, bool force);
>  
>  /*
>   * Before R2 the timer and performance counter interrupts were both fixed to
> diff --git a/arch/mips/loongson64/loongson-3/irq.c b/arch/mips/loongson64/loongson-3/irq.c
> index 2e6e205..e8b7a47 100644
> --- a/arch/mips/loongson64/loongson-3/irq.c
> +++ b/arch/mips/loongson64/loongson-3/irq.c
> @@ -10,32 +10,68 @@
>  #include "smp.h"
>  
>  extern void loongson3_send_irq_by_ipi(int cpu, int irqs);
> +
> +unsigned int irq_cpu[16] = {[0 ... 15] = -1};
>  unsigned int ht_irq[] = {0, 1, 3, 4, 5, 6, 7, 8, 12, 14, 15};
>  unsigned int local_irq = 1<<0 | 1<<1 | 1<<2 | 1<<7 | 1<<8 | 1<<12;
>  
> +int plat_set_irq_affinity(struct irq_data *d, const struct cpumask *affinity,
> +			  bool force)
> +{
> +	unsigned int cpu;
> +	struct cpumask new_affinity;
> +
> +	/* I/O devices are connected on package-0 */
> +	cpumask_copy(&new_affinity, affinity);
> +	for_each_cpu(cpu, affinity)
> +		if (cpu_data[cpu].package > 0)
> +			cpumask_clear_cpu(cpu, &new_affinity);
> +
> +	if (cpumask_empty(&new_affinity))
> +		return -EINVAL;
> +
> +	cpumask_copy(d->common->affinity, &new_affinity);
> +
> +	return IRQ_SET_MASK_OK_NOCOPY;
> +}
> +
>  static void ht_irqdispatch(void)
>  {
> -	unsigned int i, irq, irq0, irq1;
> -	static unsigned int dest_cpu = 0;
> +	unsigned int i, irq;
> +	struct irq_data *irqd;
> +	struct cpumask affinity;
>  
>  	irq = LOONGSON_HT1_INT_VECTOR(0);
>  	LOONGSON_HT1_INT_VECTOR(0) = irq; /* Acknowledge the IRQs */
>  
> -	irq0 = irq & local_irq;  /* handled by local core */
> -	irq1 = irq & ~local_irq; /* balanced by other cores */
> +	for (i = 0; i < ARRAY_SIZE(ht_irq); i++) {
> +		if (!(irq & (0x1 << ht_irq[i])))
> +			continue;
>  
> -	if (dest_cpu == 0 || !cpu_online(dest_cpu))
> -		irq0 |= irq1;
> -	else
> -		loongson3_send_irq_by_ipi(dest_cpu, irq1);
> +		/* handled by local core */
> +		if (local_irq & (0x1 << ht_irq[i])) {
> +			do_IRQ(ht_irq[i]);
> +			continue;
> +		}
>  
> -	dest_cpu = dest_cpu + 1;
> -	if (dest_cpu >= num_possible_cpus() || cpu_data[dest_cpu].package > 0)
> -		dest_cpu = 0;
> +		irqd = irq_get_irq_data(ht_irq[i]);
> +		cpumask_and(&affinity, irqd->common->affinity, cpu_active_mask);
> +		if (cpumask_empty(&affinity)) {
> +			do_IRQ(ht_irq[i]);
> +			continue;
> +		}
>  
> -	for (i = 0; i < ARRAY_SIZE(ht_irq); i++) {
> -		if (irq0 & (0x1 << ht_irq[i]))
> +		irq_cpu[ht_irq[i]] = cpumask_next(irq_cpu[ht_irq[i]], &affinity);
> +		if (irq_cpu[ht_irq[i]] >= nr_cpu_ids)
> +			irq_cpu[ht_irq[i]] = cpumask_first(&affinity);
> +
> +		if (irq_cpu[ht_irq[i]] == 0) {
>  			do_IRQ(ht_irq[i]);
> +			continue;
> +		}
> +
> +		/* balanced by other cores */
> +		loongson3_send_irq_by_ipi(irq_cpu[ht_irq[i]], (0x1 << ht_irq[i]));
>  	}
>  }
>  
> diff --git a/drivers/irqchip/irq-i8259.c b/drivers/irqchip/irq-i8259.c
> index 1aec12c..95d21e3 100644
> --- a/drivers/irqchip/irq-i8259.c
> +++ b/drivers/irqchip/irq-i8259.c
> @@ -46,6 +46,9 @@ static struct irq_chip i8259A_chip = {
>  	.irq_disable		= disable_8259A_irq,
>  	.irq_unmask		= enable_8259A_irq,
>  	.irq_mask_ack		= mask_and_ack_8259A,
> +#ifdef CONFIG_CPU_LOONGSON3
> +	.irq_set_affinity	= plat_set_irq_affinity,
> +#endif
>  };
>  
>  /*
> -- 
> 2.7.0
> 
>