On Tue, May 14, 2024 at 3:32 PM Huacai Chen <chenhuacai@xxxxxxxxxxx> wrote:
>
> Add irq_work support for LoongArch via self IPIs. This make it possible
> to run works in hardware interrupt context, which is a prerequisite for
> NOHZ_FULL.
>
> Implement:
> - arch_irq_work_raise()
> - arch_irq_work_has_interrupt()
>
> Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> ---
> arch/loongarch/include/asm/hardirq.h | 3 ++-
> arch/loongarch/include/asm/irq_work.h | 10 ++++++++++
> arch/loongarch/include/asm/smp.h | 2 ++
> arch/loongarch/kernel/paravirt.c | 6 ++++++
> arch/loongarch/kernel/smp.c | 14 ++++++++++++++
> 5 files changed, 34 insertions(+), 1 deletion(-)
> create mode 100644 arch/loongarch/include/asm/irq_work.h
>
> diff --git a/arch/loongarch/include/asm/hardirq.h b/arch/loongarch/include/asm/hardirq.h
> index d41138abcf26..1d7feb719515 100644
> --- a/arch/loongarch/include/asm/hardirq.h
> +++ b/arch/loongarch/include/asm/hardirq.h
> @@ -12,11 +12,12 @@
> extern void ack_bad_irq(unsigned int irq);
> #define ack_bad_irq ack_bad_irq
>
> -#define NR_IPI 2
> +#define NR_IPI 3
>
> enum ipi_msg_type {
> IPI_RESCHEDULE,
> IPI_CALL_FUNCTION,
> + IPI_IRQ_WORK,
> };
>
> typedef struct {
> diff --git a/arch/loongarch/include/asm/irq_work.h b/arch/loongarch/include/asm/irq_work.h
> new file mode 100644
> index 000000000000..d63076e9160d
> --- /dev/null
> +++ b/arch/loongarch/include/asm/irq_work.h
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_LOONGARCH_IRQ_WORK_H
> +#define _ASM_LOONGARCH_IRQ_WORK_H
> +
> +static inline bool arch_irq_work_has_interrupt(void)
> +{
> + return IS_ENABLED(CONFIG_SMP);
I think it is "return true," or it will cause the warning.
void __init tick_nohz_init(void)
{
int cpu, ret;
if (!tick_nohz_full_running)
return;
/*
* Full dynticks uses IRQ work to drive the tick rescheduling on safe
* locking contexts. But then we need IRQ work to raise its own
* interrupts to avoid circular dependency on the tick.
*/
if (!arch_irq_work_has_interrupt()) {
pr_warn("NO_HZ: Can't run full dynticks because arch
doesn't support IRQ work self-IPIs\n");
cpumask_clear(tick_nohz_full_mask);
tick_nohz_full_running = false;
return;
}
Others LGTM!
Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
> +}
> +
> +#endif /* _ASM_LOONGARCH_IRQ_WORK_H */
> diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
> index 278700cfee88..50db503f44e3 100644
> --- a/arch/loongarch/include/asm/smp.h
> +++ b/arch/loongarch/include/asm/smp.h
> @@ -69,9 +69,11 @@ extern int __cpu_logical_map[NR_CPUS];
> #define ACTION_BOOT_CPU 0
> #define ACTION_RESCHEDULE 1
> #define ACTION_CALL_FUNCTION 2
> +#define ACTION_IRQ_WORK 3
> #define SMP_BOOT_CPU BIT(ACTION_BOOT_CPU)
> #define SMP_RESCHEDULE BIT(ACTION_RESCHEDULE)
> #define SMP_CALL_FUNCTION BIT(ACTION_CALL_FUNCTION)
> +#define SMP_IRQ_WORK BIT(ACTION_IRQ_WORK)
>
> struct secondary_data {
> unsigned long stack;
> diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
> index 1633ed4f692f..4272d2447445 100644
> --- a/arch/loongarch/kernel/paravirt.c
> +++ b/arch/loongarch/kernel/paravirt.c
> @@ -2,6 +2,7 @@
> #include <linux/export.h>
> #include <linux/types.h>
> #include <linux/interrupt.h>
> +#include <linux/irq_work.h>
> #include <linux/jump_label.h>
> #include <linux/kvm_para.h>
> #include <linux/static_call.h>
> @@ -97,6 +98,11 @@ static irqreturn_t pv_ipi_interrupt(int irq, void *dev)
> info->ipi_irqs[IPI_CALL_FUNCTION]++;
> }
>
> + if (action & SMP_IRQ_WORK) {
> + irq_work_run();
> + info->ipi_irqs[IPI_IRQ_WORK]++;
> + }
> +
> return IRQ_HANDLED;
> }
>
> diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c
> index 0dfe2388ef41..7366de776f6e 100644
> --- a/arch/loongarch/kernel/smp.c
> +++ b/arch/loongarch/kernel/smp.c
> @@ -13,6 +13,7 @@
> #include <linux/cpumask.h>
> #include <linux/init.h>
> #include <linux/interrupt.h>
> +#include <linux/irq_work.h>
> #include <linux/profile.h>
> #include <linux/seq_file.h>
> #include <linux/smp.h>
> @@ -70,6 +71,7 @@ static DEFINE_PER_CPU(int, cpu_state);
> static const char *ipi_types[NR_IPI] __tracepoint_string = {
> [IPI_RESCHEDULE] = "Rescheduling interrupts",
> [IPI_CALL_FUNCTION] = "Function call interrupts",
> + [IPI_IRQ_WORK] = "IRQ work interrupts",
> };
>
> void show_ipi_list(struct seq_file *p, int prec)
> @@ -217,6 +219,13 @@ void arch_smp_send_reschedule(int cpu)
> }
> EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
>
> +#ifdef CONFIG_IRQ_WORK
> +void arch_irq_work_raise(void)
> +{
> + mp_ops.send_ipi_single(smp_processor_id(), ACTION_IRQ_WORK);
> +}
> +#endif
> +
> static irqreturn_t loongson_ipi_interrupt(int irq, void *dev)
> {
> unsigned int action;
> @@ -234,6 +243,11 @@ static irqreturn_t loongson_ipi_interrupt(int irq, void *dev)
> per_cpu(irq_stat, cpu).ipi_irqs[IPI_CALL_FUNCTION]++;
> }
>
> + if (action & SMP_IRQ_WORK) {
> + irq_work_run();
> + per_cpu(irq_stat, cpu).ipi_irqs[IPI_IRQ_WORK]++;
> + }
> +
> return IRQ_HANDLED;
> }
>
> --
> 2.43.0
>
--
Best Regards
Guo Ren
