[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/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index 6578f40..4a59404 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -33,6 +33,7 @@
#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/sysdev.h>
+
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/desc.h>
@@ -222,13 +223,21 @@
clear_IO_APIC_pin(apic, pin);
}
+#ifdef CONFIG_SMP
static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t cpumask)
{
unsigned long flags;
int pin;
struct irq_pin_list *entry = irq_2_pin + irq;
unsigned int apicid_value;
+ cpumask_t tmp;
+ cpus_and(tmp, cpumask, cpu_online_map);
+ if (cpus_empty(tmp))
+ tmp = TARGET_CPUS;
+
+ cpus_and(cpumask, tmp, CPU_MASK_ALL);
+
apicid_value = cpu_mask_to_apicid(cpumask);
/* Prepare to do the io_apic_write */
apicid_value = apicid_value << 24;
@@ -242,6 +251,7 @@
break;
entry = irq_2_pin + entry->next;
}
+ set_irq_info(irq, cpumask);
spin_unlock_irqrestore(&ioapic_lock, flags);
}
@@ -259,7 +269,6 @@
# define Dprintk(x...)
# endif
-cpumask_t __cacheline_aligned pending_irq_balance_cpumask[NR_IRQS];
#define IRQBALANCE_CHECK_ARCH -999
static int irqbalance_disabled = IRQBALANCE_CHECK_ARCH;
@@ -328,12 +337,7 @@
cpus_and(allowed_mask, cpu_online_map, irq_affinity[irq]);
new_cpu = move(cpu, allowed_mask, now, 1);
if (cpu != new_cpu) {
- irq_desc_t *desc = irq_desc + irq;
- unsigned long flags;
-
- spin_lock_irqsave(&desc->lock, flags);
- pending_irq_balance_cpumask[irq] = cpumask_of_cpu(new_cpu);
- spin_unlock_irqrestore(&desc->lock, flags);
+ set_pending_irq(irq, cpumask_of_cpu(new_cpu));
}
}
@@ -528,16 +532,12 @@
cpus_and(tmp, target_cpu_mask, allowed_mask);
if (!cpus_empty(tmp)) {
- irq_desc_t *desc = irq_desc + selected_irq;
- unsigned long flags;
Dprintk("irq = %d moved to cpu = %d\n",
selected_irq, min_loaded);
/* mark for change destination */
- spin_lock_irqsave(&desc->lock, flags);
- pending_irq_balance_cpumask[selected_irq] =
- cpumask_of_cpu(min_loaded);
- spin_unlock_irqrestore(&desc->lock, flags);
+ set_pending_irq(selected_irq, cpumask_of_cpu(min_loaded));
+
/* Since we made a change, come back sooner to
* check for more variation.
*/
@@ -568,7 +568,8 @@
/* push everything to CPU 0 to give us a starting point. */
for (i = 0 ; i < NR_IRQS ; i++) {
- pending_irq_balance_cpumask[i] = cpumask_of_cpu(0);
+ pending_irq_cpumask[i] = cpumask_of_cpu(0);
+ set_pending_irq(i, cpumask_of_cpu(0));
}
for ( ; ; ) {
@@ -647,20 +648,9 @@
__setup("noirqbalance", irqbalance_disable);
-static inline void move_irq(int irq)
-{
- /* note - we hold the desc->lock */
- if (unlikely(!cpus_empty(pending_irq_balance_cpumask[irq]))) {
- set_ioapic_affinity_irq(irq, pending_irq_balance_cpumask[irq]);
- cpus_clear(pending_irq_balance_cpumask[irq]);
- }
-}
-
late_initcall(balanced_irq_init);
-
-#else /* !CONFIG_IRQBALANCE */
-static inline void move_irq(int irq) { }
#endif /* CONFIG_IRQBALANCE */
+#endif /* CONFIG_SMP */
#ifndef CONFIG_SMP
void fastcall send_IPI_self(int vector)
@@ -820,6 +810,7 @@
* 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;
@@ -838,6 +829,7 @@
}
}
+#endif
/*
* EISA Edge/Level control register, ELCR
@@ -1249,6 +1241,7 @@
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);
}
}
@@ -1944,6 +1937,7 @@
{
int irq = vector_to_irq(vector);
+ move_irq(vector);
ack_edge_ioapic_irq(irq);
}
@@ -1958,6 +1952,7 @@
{
int irq = vector_to_irq(vector);
+ move_irq(vector);
end_level_ioapic_irq(irq);
}
@@ -1975,14 +1970,17 @@
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
/*
* Level and edge triggered IO-APIC interrupts need different handling,
@@ -2000,7 +1998,9 @@
.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 = {
@@ -2011,7 +2011,9 @@
.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)
@@ -2569,6 +2571,7 @@
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;