linux-kernel - [PATCH 5/5] xen: events: use per-cpu variable for cpu_evtchn

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Date:	Mon, 25 Oct 2010 17:23:33 +0100
From:	Ian Campbell <ian.campbell@...rix.com>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
Cc:	Stefano Stabellini <Stefano.Stabellini@...citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
	mingo@...e.hu, xen-devel@...ts.xensource.com, tglx@...utronix.de,
	Ian Campbell <ian.campbell@...rix.com>
Subject: [PATCH 5/5] xen: events: use per-cpu variable for cpu_evtchn_mask

I can't see any reason why it isn't already.

Signed-off-by: Ian Campbell <ian.campbell@...rix.com>
---
 drivers/xen/events.c |   31 +++++++++++--------------------
 1 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 9b58505..144ff72 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -110,19 +110,9 @@ static int *pirq_to_irq;
 static int nr_pirqs;
 
 static int *evtchn_to_irq;
-struct cpu_evtchn_s {
-	unsigned long bits[NR_EVENT_CHANNELS/BITS_PER_LONG];
-};
 
-static __initdata struct cpu_evtchn_s init_evtchn_mask = {
-	.bits[0 ... (NR_EVENT_CHANNELS/BITS_PER_LONG)-1] = ~0ul,
-};
-static struct cpu_evtchn_s *cpu_evtchn_mask_p = &init_evtchn_mask;
-
-static inline unsigned long *cpu_evtchn_mask(int cpu)
-{
-	return cpu_evtchn_mask_p[cpu].bits;
-}
+static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG],
+		      cpu_evtchn_mask);
 
 /* Xen will never allocate port zero for any purpose. */
 #define VALID_EVTCHN(chn)	((chn) != 0)
@@ -301,7 +291,7 @@ static inline unsigned long active_evtchns(unsigned int cpu,
 					   unsigned int idx)
 {
 	return (sh->evtchn_pending[idx] &
-		cpu_evtchn_mask(cpu)[idx] &
+		per_cpu(cpu_evtchn_mask, cpu)[idx] &
 		~sh->evtchn_mask[idx]);
 }
 
@@ -314,8 +304,8 @@ static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 	cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
 #endif
 
-	__clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
-	__set_bit(chn, cpu_evtchn_mask(cpu));
+	__clear_bit(chn, per_cpu(cpu_evtchn_mask, cpu_from_irq(irq)));
+	__set_bit(chn, per_cpu(cpu_evtchn_mask, cpu));
 
 	info_for_irq(irq)->cpu = cpu;
 }
@@ -332,7 +322,11 @@ static void init_evtchn_cpu_bindings(void)
 	}
 #endif
 
-	memset(cpu_evtchn_mask(0), ~0, sizeof(struct cpu_evtchn_s));
+	printk(KERN_CRIT "%s: CPU0 at %p size %zd\n", __func__,
+	       per_cpu(cpu_evtchn_mask, 0),
+	       sizeof(per_cpu(cpu_evtchn_mask, 0)));
+	memset(per_cpu(cpu_evtchn_mask, 0), ~0,
+	       sizeof(per_cpu(cpu_evtchn_mask, 0)));
 }
 
 static inline void clear_evtchn(int port)
@@ -1034,7 +1028,7 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 {
 	struct shared_info *sh = HYPERVISOR_shared_info;
 	int cpu = smp_processor_id();
-	unsigned long *cpu_evtchn = cpu_evtchn_mask(cpu);
+	unsigned long *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);
 	int i;
 	unsigned long flags;
 	static DEFINE_SPINLOCK(debug_lock);
@@ -1539,9 +1533,6 @@ void __init xen_init_IRQ(void)
 	int i, rc;
 	struct physdev_nr_pirqs op_nr_pirqs;
 
-	cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
-				    GFP_KERNEL);
-
 	rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_nr_pirqs, &op_nr_pirqs);
 	if (rc < 0) {
 		nr_pirqs = nr_irqs;
-- 
1.5.6.5

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