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authorSuresh Siddha <suresh.b.siddha@intel.com>2009-10-26 14:24:36 -0800
committerIngo Molnar <mingo@elte.hu>2009-11-02 15:56:37 +0100
commit5231a68614b94f60e8f6c56bc6e3d75955b9e75e (patch)
tree0e7cb7aecbb0d18617d68bb85a4e9703c7299c55 /arch
parentb3ec0a37a7907813bb4fb85a2d94102c152470b7 (diff)
x86: Remove local_irq_enable()/local_irq_disable() in fixup_irqs()
To ensure that we handle all the pending interrupts (destined for this cpu that is going down) in the interrupt subsystem before the cpu goes offline, fixup_irqs() does: local_irq_enable(); mdelay(1); local_irq_disable(); Enabling interrupts is not a good thing as this cpu is already offline. So this patch replaces that logic with, mdelay(1); check APIC_IRR bits Retrigger the irq at the new destination if any interrupt has arrived via IPI. For IO-APIC level triggered interrupts, this retrigger IPI will appear as an edge interrupt. ack_apic_level() will detect this condition and IO-APIC RTE's remoteIRR is cleared using directed EOI(using IO-APIC EOI register) on Intel platforms and for others it uses the existing mask+edge logic followed by unmask+level. We can also remove mdelay() and then send spuriuous interrupts to new cpu targets for all the irqs that were handled previously by this cpu that is going offline. While it works, I have seen spurious interrupt messages (nothing wrong but still annoying messages during cpu offline, which can be seen during suspend/resume etc) Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Acked-by: Gary Hade <garyhade@us.ibm.com> Cc: Eric W. Biederman <ebiederm@xmission.com> LKML-Reference: <20091026230002.043281924@sbs-t61.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/irq.c32
1 files changed, 28 insertions, 4 deletions
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index b10a5e1da06c..8a82728d47c1 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -281,7 +281,7 @@ EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
/* A cpu has been removed from cpu_online_mask. Reset irq affinities. */
void fixup_irqs(void)
{
- unsigned int irq;
+ unsigned int irq, vector;
static int warned;
struct irq_desc *desc;
@@ -336,9 +336,33 @@ void fixup_irqs(void)
printk("Cannot set affinity for irq %i\n", irq);
}
- /* That doesn't seem sufficient. Give it 1ms. */
- local_irq_enable();
+ /*
+ * We can remove mdelay() and then send spuriuous interrupts to
+ * new cpu targets for all the irqs that were handled previously by
+ * this cpu. While it works, I have seen spurious interrupt messages
+ * (nothing wrong but still...).
+ *
+ * So for now, retain mdelay(1) and check the IRR and then send those
+ * interrupts to new targets as this cpu is already offlined...
+ */
mdelay(1);
- local_irq_disable();
+
+ for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
+ unsigned int irr;
+
+ if (__get_cpu_var(vector_irq)[vector] < 0)
+ continue;
+
+ irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
+ if (irr & (1 << (vector % 32))) {
+ irq = __get_cpu_var(vector_irq)[vector];
+
+ desc = irq_to_desc(irq);
+ spin_lock(&desc->lock);
+ if (desc->chip->retrigger)
+ desc->chip->retrigger(irq);
+ spin_unlock(&desc->lock);
+ }
+ }
}
#endif