xen: use percpu interrupts for IPIs and VIRQs

IPIs and VIRQs are inherently per-cpu event types, so treat them as such: - use a specific percpu irq_chip implementation, and - handle them with handle_percpu_irq This makes the path for delivering these interrupts more efficient (no masking/unmasking, no locks), and it avoid problems with attempts to migrate them. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Stable Kernel <stable@kernel.org>

xen: use percpu interrupts for IPIs and VIRQs
IPIs and VIRQs are inherently per-cpu event types, so treat them as such: - use a specific percpu irq_chip implementation, and - handle them with handle_percpu_irq This makes the path for delivering these interrupts more efficient (no masking/unmasking, no locks), and it avoid problems with attempts to migrate them. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Stable Kernel <stable@kernel.org>
Jeremy Fitzhardinge
1 parent 76be97c1fc
Showing 1 changed file with 15 additions and 4 deletions Side-by-side Diff
drivers/xen/events.c
@@ -112,6 +112,7 @@
 #define VALID_EVTCHN(chn)	((chn) != 0)
  
 static struct irq_chip xen_dynamic_chip;
+static struct irq_chip xen_percpu_chip;
  
 /* Constructor for packed IRQ information. */
 static struct irq_info mk_unbound_info(void)
@@ -403,8 +404,8 @@
 		if (irq < 0)
 			goto out;
  
-		set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
-					      handle_level_irq, "ipi");
+		set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
+					      handle_percpu_irq, "ipi");
  
 		bind_ipi.vcpu = cpu;
 		if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
@@ -444,8 +445,8 @@
  
 		irq = find_unbound_irq();
  
-		set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
-					      handle_level_irq, "virq");
+		set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
+					      handle_percpu_irq, "virq");
  
 		evtchn_to_irq[evtchn] = irq;
 		irq_info[irq] = mk_virq_info(evtchn, virq);
@@ -962,6 +963,16 @@
 	.ack		= ack_dynirq,
 	.set_affinity	= set_affinity_irq,
 	.retrigger	= retrigger_dynirq,
+};
+
+static struct irq_chip xen_percpu_chip __read_mostly = {
+	.name		= "xen-percpu",
+
+	.disable	= disable_dynirq,
+	.mask		= disable_dynirq,
+	.unmask		= enable_dynirq,
+
+	.ack		= ack_dynirq,
 };
  
 int xen_set_callback_via(uint64_t via)
...	...	@@ -112,6 +112,7 @@
112	112	#define VALID_EVTCHN(chn) ((chn) != 0)
113	113
114	114	static struct irq_chip xen_dynamic_chip;
	115	+static struct irq_chip xen_percpu_chip;
115	116
116	117	/* Constructor for packed IRQ information. */
117	118	static struct irq_info mk_unbound_info(void)
...	...	@@ -403,8 +404,8 @@
403	404	if (irq < 0)
404	405	goto out;
405	406
406		- set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
407		- handle_level_irq, "ipi");
	407	+ set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
	408	+ handle_percpu_irq, "ipi");
408	409
409	410	bind_ipi.vcpu = cpu;
410	411	if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
...	...	@@ -444,8 +445,8 @@
444	445
445	446	irq = find_unbound_irq();
446	447
447		- set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
448		- handle_level_irq, "virq");
	448	+ set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
	449	+ handle_percpu_irq, "virq");
449	450
450	451	evtchn_to_irq[evtchn] = irq;
451	452	irq_info[irq] = mk_virq_info(evtchn, virq);
...	...	@@ -962,6 +963,16 @@
962	963	.ack = ack_dynirq,
963	964	.set_affinity = set_affinity_irq,
964	965	.retrigger = retrigger_dynirq,
	966	+};
	967	+
	968	+static struct irq_chip xen_percpu_chip __read_mostly = {
	969	+ .name = "xen-percpu",
	970	+
	971	+ .disable = disable_dynirq,
	972	+ .mask = disable_dynirq,
	973	+ .unmask = enable_dynirq,
	974	+
	975	+ .ack = ack_dynirq,
965	976	};
966	977
967	978	int xen_set_callback_via(uint64_t via)