Linux Virtualization - Dec 2013 - [PATCH v3 [resend] 14/18] smp, x86, xen: kill SMP single function call interrupt

Commit 9a46ad6d6df3b54 "smp: make smp_call_function_many() use logic
similar to smp_call_function_single()" has unified the way to handle
single and multiple cross-CPU function calls. Now only one interrupt
is needed for architecture specific code to support generic SMP function
call interfaces, so kill the redundant single function call interrupt.

Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Shaohua Li <shli at kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra at chello.nl>
Cc: Ingo Molnar <mingo at elte.hu>
Cc: Steven Rostedt <rostedt at goodmis.org>
Cc: Jiri Kosina <trivial at kernel.org>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: "H. Peter Anvin" <hpa at zytor.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
Cc: Jeremy Fitzhardinge <jeremy at goop.org>
Cc: Sebastian Andrzej Siewior <sebastian at breakpoint.cc>
Cc: x86 at kernel.org
Cc: xen-devel at lists.xensource.com
Cc: virtualization at lists.linux-foundation.org
Signed-off-by: Jiang Liu <liuj97 at gmail.com>
---
 arch/x86/include/asm/xen/events.h |  1 -
 arch/x86/xen/smp.c                | 38 ++------------------------------------
 2 files changed, 2 insertions(+), 37 deletions(-)

diff --git a/arch/x86/include/asm/xen/events.h
b/arch/x86/include/asm/xen/events.h
index 608a79d..a9e54dc 100644
--- a/arch/x86/include/asm/xen/events.h
+++ b/arch/x86/include/asm/xen/events.h
@@ -4,7 +4,6 @@
 enum ipi_vector {
 	XEN_RESCHEDULE_VECTOR,
 	XEN_CALL_FUNCTION_VECTOR,
-	XEN_CALL_FUNCTION_SINGLE_VECTOR,
 	XEN_SPIN_UNLOCK_VECTOR,
 	XEN_IRQ_WORK_VECTOR,
 	XEN_NMI_VECTOR,
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index c36b325..7cf1689 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -46,12 +46,10 @@ struct xen_common_irq {
 };
 static DEFINE_PER_CPU(struct xen_common_irq, xen_resched_irq) = { .irq = -1 };
 static DEFINE_PER_CPU(struct xen_common_irq, xen_callfunc_irq) = { .irq = -1 };
-static DEFINE_PER_CPU(struct xen_common_irq, xen_callfuncsingle_irq) = { .irq =
-1 };
 static DEFINE_PER_CPU(struct xen_common_irq, xen_irq_work) = { .irq = -1 };
 static DEFINE_PER_CPU(struct xen_common_irq, xen_debug_irq) = { .irq = -1 };
 
 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
-static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id);
 static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id);
 
 /*
@@ -123,13 +121,6 @@ static void xen_smp_intr_free(unsigned int cpu)
 		kfree(per_cpu(xen_debug_irq, cpu).name);
 		per_cpu(xen_debug_irq, cpu).name = NULL;
 	}
-	if (per_cpu(xen_callfuncsingle_irq, cpu).irq >= 0) {
-		unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu).irq,
-				       NULL);
-		per_cpu(xen_callfuncsingle_irq, cpu).irq = -1;
-		kfree(per_cpu(xen_callfuncsingle_irq, cpu).name);
-		per_cpu(xen_callfuncsingle_irq, cpu).name = NULL;
-	}
 	if (xen_hvm_domain())
 		return;
 
@@ -178,18 +169,6 @@ static int xen_smp_intr_init(unsigned int cpu)
 	per_cpu(xen_debug_irq, cpu).irq = rc;
 	per_cpu(xen_debug_irq, cpu).name = debug_name;
 
-	callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
-	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
-				    cpu,
-				    xen_call_function_single_interrupt,
-				    IRQF_PERCPU|IRQF_NOBALANCING,
-				    callfunc_name,
-				    NULL);
-	if (rc < 0)
-		goto fail;
-	per_cpu(xen_callfuncsingle_irq, cpu).irq = rc;
-	per_cpu(xen_callfuncsingle_irq, cpu).name = callfunc_name;
-
 	/*
 	 * The IRQ worker on PVHVM goes through the native path and uses the
 	 * IPI mechanism.
@@ -569,8 +548,7 @@ static void xen_smp_send_call_function_ipi(const struct
cpumask *mask)
 
 static void xen_smp_send_call_function_single_ipi(int cpu)
 {
-	__xen_send_IPI_mask(cpumask_of(cpu),
-			  XEN_CALL_FUNCTION_SINGLE_VECTOR);
+	__xen_send_IPI_mask(cpumask_of(cpu), XEN_CALL_FUNCTION_VECTOR);
 }
 
 static inline int xen_map_vector(int vector)
@@ -582,10 +560,8 @@ static inline int xen_map_vector(int vector)
 		xen_vector = XEN_RESCHEDULE_VECTOR;
 		break;
 	case CALL_FUNCTION_VECTOR:
-		xen_vector = XEN_CALL_FUNCTION_VECTOR;
-		break;
 	case CALL_FUNCTION_SINGLE_VECTOR:
-		xen_vector = XEN_CALL_FUNCTION_SINGLE_VECTOR;
+		xen_vector = XEN_CALL_FUNCTION_VECTOR;
 		break;
 	case IRQ_WORK_VECTOR:
 		xen_vector = XEN_IRQ_WORK_VECTOR;
@@ -663,16 +639,6 @@ static irqreturn_t xen_call_function_interrupt(int irq,
void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
-{
-	irq_enter();
-	generic_smp_call_function_single_interrupt();
-	inc_irq_stat(irq_call_count);
-	irq_exit();
-
-	return IRQ_HANDLED;
-}
-
 static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id)
 {
 	irq_enter();
-- 
1.8.1.2

On Mon, Dec 16, 2013 at 12:36:36AM +0800, Jiang Liu
wrote:
> Commit 9a46ad6d6df3b54 "smp: make smp_call_function_many() use logic
> similar to smp_call_function_single()" has unified the way to handle
> single and multiple cross-CPU function calls. Now only one interrupt
> is needed for architecture specific code to support generic SMP function
> call interfaces, so kill the redundant single function call interrupt.
> 
> Cc: Andrew Morton <akpm at linux-foundation.org>
> Cc: Shaohua Li <shli at kernel.org>
> Cc: Peter Zijlstra <a.p.zijlstra at chello.nl>
> Cc: Ingo Molnar <mingo at elte.hu>
> Cc: Steven Rostedt <rostedt at goodmis.org>
> Cc: Jiri Kosina <trivial at kernel.org>
> Cc: Thomas Gleixner <tglx at linutronix.de>
> Cc: "H. Peter Anvin" <hpa at zytor.com>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
I presume this has been tested?
> Cc: Jeremy Fitzhardinge <jeremy at goop.org>
> Cc: Sebastian Andrzej Siewior <sebastian at breakpoint.cc>
> Cc: x86 at kernel.org
> Cc: xen-devel at lists.xensource.com
> Cc: virtualization at lists.linux-foundation.org
> Signed-off-by: Jiang Liu <liuj97 at gmail.com>
> ---
>  arch/x86/include/asm/xen/events.h |  1 -
>  arch/x86/xen/smp.c                | 38
++------------------------------------
>  2 files changed, 2 insertions(+), 37 deletions(-)
> 
> diff --git a/arch/x86/include/asm/xen/events.h
b/arch/x86/include/asm/xen/events.h
> index 608a79d..a9e54dc 100644
> --- a/arch/x86/include/asm/xen/events.h
> +++ b/arch/x86/include/asm/xen/events.h
> @@ -4,7 +4,6 @@
>  enum ipi_vector {
>  	XEN_RESCHEDULE_VECTOR,
>  	XEN_CALL_FUNCTION_VECTOR,
> -	XEN_CALL_FUNCTION_SINGLE_VECTOR,
>  	XEN_SPIN_UNLOCK_VECTOR,
>  	XEN_IRQ_WORK_VECTOR,
>  	XEN_NMI_VECTOR,
> diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
> index c36b325..7cf1689 100644
> --- a/arch/x86/xen/smp.c
> +++ b/arch/x86/xen/smp.c
> @@ -46,12 +46,10 @@ struct xen_common_irq {
>  };
>  static DEFINE_PER_CPU(struct xen_common_irq, xen_resched_irq) = { .irq =
-1 };
>  static DEFINE_PER_CPU(struct xen_common_irq, xen_callfunc_irq) = { .irq =
-1 };
> -static DEFINE_PER_CPU(struct xen_common_irq, xen_callfuncsingle_irq) = {
.irq = -1 };
>  static DEFINE_PER_CPU(struct xen_common_irq, xen_irq_work) = { .irq = -1
};
>  static DEFINE_PER_CPU(struct xen_common_irq, xen_debug_irq) = { .irq = -1
};
>  
>  static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
> -static irqreturn_t xen_call_function_single_interrupt(int irq, void
*dev_id);
>  static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id);
>  
>  /*
> @@ -123,13 +121,6 @@ static void xen_smp_intr_free(unsigned int cpu)
>  		kfree(per_cpu(xen_debug_irq, cpu).name);
>  		per_cpu(xen_debug_irq, cpu).name = NULL;
>  	}
> -	if (per_cpu(xen_callfuncsingle_irq, cpu).irq >= 0) {
> -		unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu).irq,
> -				       NULL);
> -		per_cpu(xen_callfuncsingle_irq, cpu).irq = -1;
> -		kfree(per_cpu(xen_callfuncsingle_irq, cpu).name);
> -		per_cpu(xen_callfuncsingle_irq, cpu).name = NULL;
> -	}
>  	if (xen_hvm_domain())
>  		return;
>  
> @@ -178,18 +169,6 @@ static int xen_smp_intr_init(unsigned int cpu)
>  	per_cpu(xen_debug_irq, cpu).irq = rc;
>  	per_cpu(xen_debug_irq, cpu).name = debug_name;
>  
> -	callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
> -	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
> -				    cpu,
> -				    xen_call_function_single_interrupt,
> -				    IRQF_PERCPU|IRQF_NOBALANCING,
> -				    callfunc_name,
> -				    NULL);
> -	if (rc < 0)
> -		goto fail;
> -	per_cpu(xen_callfuncsingle_irq, cpu).irq = rc;
> -	per_cpu(xen_callfuncsingle_irq, cpu).name = callfunc_name;
> -
>  	/*
>  	 * The IRQ worker on PVHVM goes through the native path and uses the
>  	 * IPI mechanism.
> @@ -569,8 +548,7 @@ static void xen_smp_send_call_function_ipi(const struct
cpumask *mask)
>  
>  static void xen_smp_send_call_function_single_ipi(int cpu)
>  {
> -	__xen_send_IPI_mask(cpumask_of(cpu),
> -			  XEN_CALL_FUNCTION_SINGLE_VECTOR);
> +	__xen_send_IPI_mask(cpumask_of(cpu), XEN_CALL_FUNCTION_VECTOR);
>  }
>  
>  static inline int xen_map_vector(int vector)
> @@ -582,10 +560,8 @@ static inline int xen_map_vector(int vector)
>  		xen_vector = XEN_RESCHEDULE_VECTOR;
>  		break;
>  	case CALL_FUNCTION_VECTOR:
> -		xen_vector = XEN_CALL_FUNCTION_VECTOR;
> -		break;
>  	case CALL_FUNCTION_SINGLE_VECTOR:
> -		xen_vector = XEN_CALL_FUNCTION_SINGLE_VECTOR;
> +		xen_vector = XEN_CALL_FUNCTION_VECTOR;
>  		break;
>  	case IRQ_WORK_VECTOR:
>  		xen_vector = XEN_IRQ_WORK_VECTOR;
> @@ -663,16 +639,6 @@ static irqreturn_t xen_call_function_interrupt(int
irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> -static irqreturn_t xen_call_function_single_interrupt(int irq, void
*dev_id)
> -{
> -	irq_enter();
> -	generic_smp_call_function_single_interrupt();
> -	inc_irq_stat(irq_call_count);
> -	irq_exit();
> -
> -	return IRQ_HANDLED;
> -}
> -
>  static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id)
>  {
>  	irq_enter();
> -- 
> 1.8.1.2
>