[PATCH] x86/x86_64: deferred handling of writes to /proc/irqxx/smp_affinity
When handling writes to /proc/irq, current code is re-programming rte
entries directly. This is not recommended and could potentially cause
chipset's to lockup, or cause missing interrupts.
CONFIG_IRQ_BALANCE does this correctly, where it re-programs only when the
interrupt is pending. The same needs to be done for /proc/irq handling as well.
Otherwise user space irq balancers are really not doing the right thing.
- Changed pending_irq_balance_cpumask to pending_irq_migrate_cpumask for
lack of a generic name.
- added move_irq out of IRQ_BALANCE, and added this same to X86_64
- Added new proc handler for write, so we can do deferred write at irq
handling time.
- Display of /proc/irq/XX/smp_affinity used to display CPU_MASKALL, instead
it now shows only active cpu masks, or exactly what was set.
- Provided a common move_irq implementation, instead of duplicating
when using generic irq framework.
Tested on i386/x86_64 and ia64 with CONFIG_PCI_MSI turned on and off.
Tested UP builds as well.
MSI testing: tbd: I have cards, need to look for a x-over cable, although I
did test an earlier version of this patch. Will test in a couple days.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Acked-by: Zwane Mwaikambo <zwane@holomorphy.com>
Grudgingly-acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Coywolf Qi Hunt <coywolf@lovecn.org>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index d206d7e..76bcc4e 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -78,6 +78,54 @@
#define vector_to_irq(vector) (vector)
#endif
+#define __DO_ACTION(R, ACTION, FINAL) \
+ \
+{ \
+ int pin; \
+ struct irq_pin_list *entry = irq_2_pin + irq; \
+ \
+ for (;;) { \
+ unsigned int reg; \
+ pin = entry->pin; \
+ if (pin == -1) \
+ break; \
+ reg = io_apic_read(entry->apic, 0x10 + R + pin*2); \
+ reg ACTION; \
+ io_apic_modify(entry->apic, reg); \
+ if (!entry->next) \
+ break; \
+ entry = irq_2_pin + entry->next; \
+ } \
+ FINAL; \
+}
+
+#ifdef CONFIG_SMP
+static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t mask)
+{
+ unsigned long flags;
+ unsigned int dest;
+ cpumask_t tmp;
+
+ cpus_and(tmp, mask, cpu_online_map);
+ if (cpus_empty(tmp))
+ tmp = TARGET_CPUS;
+
+ cpus_and(mask, tmp, CPU_MASK_ALL);
+
+ dest = cpu_mask_to_apicid(mask);
+
+ /*
+ * Only the high 8 bits are valid.
+ */
+ dest = SET_APIC_LOGICAL_ID(dest);
+
+ spin_lock_irqsave(&ioapic_lock, flags);
+ __DO_ACTION(1, = dest, )
+ set_irq_info(irq, mask);
+ spin_unlock_irqrestore(&ioapic_lock, flags);
+}
+#endif
+
/*
* The common case is 1:1 IRQ<->pin mappings. Sometimes there are
* shared ISA-space IRQs, so we have to support them. We are super
@@ -101,26 +149,6 @@
entry->pin = pin;
}
-#define __DO_ACTION(R, ACTION, FINAL) \
- \
-{ \
- int pin; \
- struct irq_pin_list *entry = irq_2_pin + irq; \
- \
- for (;;) { \
- unsigned int reg; \
- pin = entry->pin; \
- if (pin == -1) \
- break; \
- reg = io_apic_read(entry->apic, 0x10 + R + pin*2); \
- reg ACTION; \
- io_apic_modify(entry->apic, reg); \
- if (!entry->next) \
- break; \
- entry = irq_2_pin + entry->next; \
- } \
- FINAL; \
-}
#define DO_ACTION(name,R,ACTION, FINAL) \
\
@@ -767,6 +795,7 @@
spin_lock_irqsave(&ioapic_lock, flags);
io_apic_write(apic, 0x11+2*pin, *(((int *)&entry)+1));
io_apic_write(apic, 0x10+2*pin, *(((int *)&entry)+0));
+ set_native_irq_info(irq, TARGET_CPUS);
spin_unlock_irqrestore(&ioapic_lock, flags);
}
}
@@ -1314,6 +1343,7 @@
*/
static void ack_edge_ioapic_irq(unsigned int irq)
{
+ move_irq(irq);
if ((irq_desc[irq].status & (IRQ_PENDING | IRQ_DISABLED))
== (IRQ_PENDING | IRQ_DISABLED))
mask_IO_APIC_irq(irq);
@@ -1343,26 +1373,10 @@
static void end_level_ioapic_irq (unsigned int irq)
{
+ move_irq(irq);
ack_APIC_irq();
}
-static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t mask)
-{
- unsigned long flags;
- unsigned int dest;
-
- dest = cpu_mask_to_apicid(mask);
-
- /*
- * Only the high 8 bits are valid.
- */
- dest = SET_APIC_LOGICAL_ID(dest);
-
- spin_lock_irqsave(&ioapic_lock, flags);
- __DO_ACTION(1, = dest, )
- spin_unlock_irqrestore(&ioapic_lock, flags);
-}
-
#ifdef CONFIG_PCI_MSI
static unsigned int startup_edge_ioapic_vector(unsigned int vector)
{
@@ -1375,6 +1389,7 @@
{
int irq = vector_to_irq(vector);
+ move_native_irq(vector);
ack_edge_ioapic_irq(irq);
}
@@ -1389,6 +1404,7 @@
{
int irq = vector_to_irq(vector);
+ move_native_irq(vector);
end_level_ioapic_irq(irq);
}
@@ -1406,14 +1422,17 @@
unmask_IO_APIC_irq(irq);
}
+#ifdef CONFIG_SMP
static void set_ioapic_affinity_vector (unsigned int vector,
cpumask_t cpu_mask)
{
int irq = vector_to_irq(vector);
+ set_native_irq_info(vector, cpu_mask);
set_ioapic_affinity_irq(irq, cpu_mask);
}
-#endif
+#endif // CONFIG_SMP
+#endif // CONFIG_PCI_MSI
/*
* Level and edge triggered IO-APIC interrupts need different handling,
@@ -1432,7 +1451,9 @@
.disable = disable_edge_ioapic,
.ack = ack_edge_ioapic,
.end = end_edge_ioapic,
+#ifdef CONFIG_SMP
.set_affinity = set_ioapic_affinity,
+#endif
};
static struct hw_interrupt_type ioapic_level_type = {
@@ -1443,7 +1464,9 @@
.disable = disable_level_ioapic,
.ack = mask_and_ack_level_ioapic,
.end = end_level_ioapic,
+#ifdef CONFIG_SMP
.set_affinity = set_ioapic_affinity,
+#endif
};
static inline void init_IO_APIC_traps(void)
@@ -1918,6 +1941,7 @@
spin_lock_irqsave(&ioapic_lock, flags);
io_apic_write(ioapic, 0x11+2*pin, *(((int *)&entry)+1));
io_apic_write(ioapic, 0x10+2*pin, *(((int *)&entry)+0));
+ set_native_irq_info(use_pci_vector() ? entry.vector : irq, TARGET_CPUS);
spin_unlock_irqrestore(&ioapic_lock, flags);
return 0;
@@ -1931,6 +1955,7 @@
* we need to reprogram the ioredtbls to cater for the cpus which have come online
* so mask in all cases should simply be TARGET_CPUS
*/
+#ifdef CONFIG_SMP
void __init setup_ioapic_dest(void)
{
int pin, ioapic, irq, irq_entry;
@@ -1949,3 +1974,4 @@
}
}
+#endif