* [PATCH v2 1/2] xen: implement apic ipi interface
2012-04-20 16:11 [PATCH v2 0/2] fix "perf top" soft lockups under Xen Lin Ming
@ 2012-04-20 16:11 ` Lin Ming
2012-04-20 16:11 ` [PATCH v2 2/2] xen: implement IRQ_WORK_VECTOR handler Lin Ming
2012-04-20 16:21 ` [PATCH v2 0/2] fix "perf top" soft lockups under Xen Konrad Rzeszutek Wilk
2 siblings, 0 replies; 4+ messages in thread
From: Lin Ming @ 2012-04-20 16:11 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Peter Zijlstra, Steven Noonan, Ben Guthro, Jeremy Fitzhardinge,
Marcus Granado, xen-devel, linux-kernel
From: Ben Guthro <ben@guthro.net>
Map native ipi vector to xen vector.
Implement apic ipi interface with xen_send_IPI_one.
Tested-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ben Guthro <ben@guthro.net>
Signed-off-by: Lin Ming <mlin@ss.pku.edu.cn>
---
arch/x86/xen/enlighten.c | 9 +++++
arch/x86/xen/smp.c | 81 +++++++++++++++++++++++++++++++++++++++++++--
arch/x86/xen/smp.h | 12 +++++++
3 files changed, 98 insertions(+), 4 deletions(-)
create mode 100644 arch/x86/xen/smp.h
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 4f51beb..1ed61c2 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -74,6 +74,7 @@
#include "xen-ops.h"
#include "mmu.h"
+#include "smp.h"
#include "multicalls.h"
EXPORT_SYMBOL_GPL(hypercall_page);
@@ -849,6 +850,14 @@ static void set_xen_basic_apic_ops(void)
apic->icr_write = xen_apic_icr_write;
apic->wait_icr_idle = xen_apic_wait_icr_idle;
apic->safe_wait_icr_idle = xen_safe_apic_wait_icr_idle;
+
+#ifdef CONFIG_SMP
+ apic->send_IPI_allbutself = xen_send_IPI_allbutself;
+ apic->send_IPI_mask_allbutself = xen_send_IPI_mask_allbutself;
+ apic->send_IPI_mask = xen_send_IPI_mask;
+ apic->send_IPI_all = xen_send_IPI_all;
+ apic->send_IPI_self = xen_send_IPI_self;
+#endif
}
#endif
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 5fac691..2dc6628 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -465,8 +465,8 @@ static void xen_smp_send_reschedule(int cpu)
xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
}
-static void xen_send_IPI_mask(const struct cpumask *mask,
- enum ipi_vector vector)
+static void __xen_send_IPI_mask(const struct cpumask *mask,
+ int vector)
{
unsigned cpu;
@@ -478,7 +478,7 @@ static void xen_smp_send_call_function_ipi(const struct cpumask *mask)
{
int cpu;
- xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
+ __xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
/* Make sure other vcpus get a chance to run if they need to. */
for_each_cpu(cpu, mask) {
@@ -491,10 +491,83 @@ 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_send_IPI_mask(cpumask_of(cpu),
XEN_CALL_FUNCTION_SINGLE_VECTOR);
}
+static inline int xen_map_vector(int vector)
+{
+ int xen_vector;
+
+ switch (vector) {
+ case RESCHEDULE_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;
+ break;
+ default:
+ xen_vector = -1;
+ printk(KERN_ERR "xen: vector 0x%x is not implemented\n",
+ vector);
+ }
+
+ return xen_vector;
+}
+
+void xen_send_IPI_mask(const struct cpumask *mask,
+ int vector)
+{
+ int xen_vector = xen_map_vector(vector);
+
+ if (xen_vector >= 0)
+ __xen_send_IPI_mask(mask, xen_vector);
+}
+
+void xen_send_IPI_all(int vector)
+{
+ int xen_vector = xen_map_vector(vector);
+
+ if (xen_vector >= 0)
+ __xen_send_IPI_mask(cpu_online_mask, xen_vector);
+}
+
+void xen_send_IPI_self(int vector)
+{
+ int xen_vector = xen_map_vector(vector);
+
+ if (xen_vector >= 0)
+ xen_send_IPI_one(smp_processor_id(), xen_vector);
+}
+
+void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
+ int vector)
+{
+ unsigned cpu;
+ unsigned int this_cpu = smp_processor_id();
+
+ if (!(num_online_cpus() > 1))
+ return;
+
+ for_each_cpu_and(cpu, mask, cpu_online_mask) {
+ if (this_cpu == cpu)
+ continue;
+
+ xen_smp_send_call_function_single_ipi(cpu);
+ }
+}
+
+void xen_send_IPI_allbutself(int vector)
+{
+ int xen_vector = xen_map_vector(vector);
+
+ if (xen_vector >= 0)
+ xen_send_IPI_mask_allbutself(cpu_online_mask, xen_vector);
+}
+
static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
{
irq_enter();
diff --git a/arch/x86/xen/smp.h b/arch/x86/xen/smp.h
new file mode 100644
index 0000000..8981a76
--- /dev/null
+++ b/arch/x86/xen/smp.h
@@ -0,0 +1,12 @@
+#ifndef _XEN_SMP_H
+
+extern void xen_send_IPI_mask(const struct cpumask *mask,
+ int vector);
+extern void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
+ int vector);
+extern void xen_send_IPI_allbutself(int vector);
+extern void physflat_send_IPI_allbutself(int vector);
+extern void xen_send_IPI_all(int vector);
+extern void xen_send_IPI_self(int vector);
+
+#endif
--
1.7.2.5
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 2/2] xen: implement IRQ_WORK_VECTOR handler
2012-04-20 16:11 [PATCH v2 0/2] fix "perf top" soft lockups under Xen Lin Ming
2012-04-20 16:11 ` [PATCH v2 1/2] xen: implement apic ipi interface Lin Ming
@ 2012-04-20 16:11 ` Lin Ming
2012-04-20 16:21 ` [PATCH v2 0/2] fix "perf top" soft lockups under Xen Konrad Rzeszutek Wilk
2 siblings, 0 replies; 4+ messages in thread
From: Lin Ming @ 2012-04-20 16:11 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Peter Zijlstra, Steven Noonan, Ben Guthro, Jeremy Fitzhardinge,
Marcus Granado, xen-devel, linux-kernel
Signed-off-by: Lin Ming <mlin@ss.pku.edu.cn>
---
arch/x86/include/asm/xen/events.h | 1 +
arch/x86/xen/smp.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 31 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/xen/events.h b/arch/x86/include/asm/xen/events.h
index 1df3541..cc146d5 100644
--- a/arch/x86/include/asm/xen/events.h
+++ b/arch/x86/include/asm/xen/events.h
@@ -6,6 +6,7 @@ enum ipi_vector {
XEN_CALL_FUNCTION_VECTOR,
XEN_CALL_FUNCTION_SINGLE_VECTOR,
XEN_SPIN_UNLOCK_VECTOR,
+ XEN_IRQ_WORK_VECTOR,
XEN_NR_IPIS,
};
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 2dc6628..3ec3f8e 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -16,6 +16,7 @@
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/smp.h>
+#include <linux/irq_work.h>
#include <asm/paravirt.h>
#include <asm/desc.h>
@@ -41,10 +42,12 @@ cpumask_var_t xen_cpu_initialized_map;
static DEFINE_PER_CPU(int, xen_resched_irq);
static DEFINE_PER_CPU(int, xen_callfunc_irq);
static DEFINE_PER_CPU(int, xen_callfuncsingle_irq);
+static DEFINE_PER_CPU(int, xen_irq_work);
static DEFINE_PER_CPU(int, xen_debug_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);
/*
* Reschedule call back.
@@ -143,6 +146,17 @@ static int xen_smp_intr_init(unsigned int cpu)
goto fail;
per_cpu(xen_callfuncsingle_irq, cpu) = rc;
+ callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu);
+ rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR,
+ cpu,
+ xen_irq_work_interrupt,
+ IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
+ callfunc_name,
+ NULL);
+ if (rc < 0)
+ goto fail;
+ per_cpu(xen_irq_work, cpu) = rc;
+
return 0;
fail:
@@ -155,6 +169,8 @@ static int xen_smp_intr_init(unsigned int cpu)
if (per_cpu(xen_callfuncsingle_irq, cpu) >= 0)
unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu),
NULL);
+ if (per_cpu(xen_irq_work, cpu) >= 0)
+ unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL);
return rc;
}
@@ -509,6 +525,9 @@ static inline int xen_map_vector(int vector)
case CALL_FUNCTION_SINGLE_VECTOR:
xen_vector = XEN_CALL_FUNCTION_SINGLE_VECTOR;
break;
+ case IRQ_WORK_VECTOR:
+ xen_vector = XEN_IRQ_WORK_VECTOR;
+ break;
default:
xen_vector = -1;
printk(KERN_ERR "xen: vector 0x%x is not implemented\n",
@@ -588,6 +607,16 @@ static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id)
+{
+ irq_enter();
+ irq_work_run();
+ inc_irq_stat(apic_irq_work_irqs);
+ irq_exit();
+
+ return IRQ_HANDLED;
+}
+
static const struct smp_ops xen_smp_ops __initconst = {
.smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
.smp_prepare_cpus = xen_smp_prepare_cpus,
@@ -634,6 +663,7 @@ static void xen_hvm_cpu_die(unsigned int cpu)
unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL);
+ unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL);
native_cpu_die(cpu);
}
--
1.7.2.5
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2 0/2] fix "perf top" soft lockups under Xen
2012-04-20 16:11 [PATCH v2 0/2] fix "perf top" soft lockups under Xen Lin Ming
2012-04-20 16:11 ` [PATCH v2 1/2] xen: implement apic ipi interface Lin Ming
2012-04-20 16:11 ` [PATCH v2 2/2] xen: implement IRQ_WORK_VECTOR handler Lin Ming
@ 2012-04-20 16:21 ` Konrad Rzeszutek Wilk
2 siblings, 0 replies; 4+ messages in thread
From: Konrad Rzeszutek Wilk @ 2012-04-20 16:21 UTC (permalink / raw)
To: Lin Ming
Cc: Peter Zijlstra, Steven Noonan, Ben Guthro, Jeremy Fitzhardinge,
Marcus Granado, xen-devel, linux-kernel
On Sat, Apr 21, 2012 at 12:11:03AM +0800, Lin Ming wrote:
> v2:
> - fix compile issues if no CONFIG_SMP, Konrad Rzeszutek Wilk
> - move inc_irq_stat after irq_work_run
They look good to me (and they work nicely - thanks!)
so putting in the 3.5 queue.
>
> These 2 patches fixed the "perf top" soft lockups under Xen
> reported by Steven at: https://lkml.org/lkml/2012/2/9/506
>
> Both Steven and I tested it and "perf top" works well now.
>
> The soft lockup code path is:
>
> __irq_work_queue
> arch_irq_work_raise
> apic->send_IPI_self(IRQ_WORK_VECTOR);
> apic_send_IPI_self
> __default_send_IPI_shortcut
> __xapic_wait_icr_idle
>
> static inline void __xapic_wait_icr_idle(void)
> {
> while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
> cpu_relax();
> }
> The lockup happens at above while looop.
>
> The cause is that Xen has not implemented the APIC IPI interface yet.
> Xen has IPI interface: xen_send_IPI_one, but it's only used in
> xen_smp_send_reschedule, xen_smp_send_call_function_ipi and
> xen_smp_send_call_function_single_ipi, etc.
>
> So we need to implement Xen's APIC IPI interface as Ben's patch does.
> And implement Xen's IRQ_WORK_VECTOR handler.
>
> Ben Guthro (1):
> xen: implement apic ipi interface
>
> Lin Ming (1):
> xen: implement IRQ_WORK_VECTOR handler
>
> arch/x86/include/asm/xen/events.h | 1 +
> arch/x86/xen/enlighten.c | 9 +++
> arch/x86/xen/smp.c | 111 +++++++++++++++++++++++++++++++++++-
> arch/x86/xen/smp.h | 12 ++++
> 4 files changed, 129 insertions(+), 4 deletions(-)
^ permalink raw reply [flat|nested] 4+ messages in thread