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authorZhang Yanmin <yanmin.zhang@intel.com>2006-06-23 05:04:22 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-23 10:42:57 -0400
commit1b61b910e99059abdd54c93aa70e84e076e33d16 (patch)
treefe2cd431dc39521a0f2d30e22c9bd3eb3e1bc317 /kernel
parentafa024c3dbccf026e45121f4b9de54cda48edbea (diff)
[PATCH] x86: kernel irq balance doesn't work
On i386, kernel irq balance doesn't work. 1) In function do_irq_balance, after kernel finds the min_loaded cpu but before calling set_pending_irq to really pin the selected_irq to the target cpu, kernel does a cpus_and with irq_affinity[selected_irq]. Later on, when the irq is acked, kernel would calls move_native_irq=>desc->handler->set_affinity to change the irq affinity. However, every function pointed by hw_interrupt_type->set_affinity(unsigned int irq, cpumask_t cpumask) always changes irq_affinity[irq] to cpumask. Next time when recalling do_irq_balance, it has to do cpu_ands again with irq_affinity[selected_irq], but irq_affinity[selected_irq] already becomes one cpu selected by the first irq balance. 2) Function balance_irq in file arch/i386/kernel/io_apic.c has the same issue. [akpm@osdl.org: cleanups] Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/irq/proc.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index d03b5eef8ce0..afacd6f585fa 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -24,6 +24,8 @@ static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];
24#ifdef CONFIG_GENERIC_PENDING_IRQ 24#ifdef CONFIG_GENERIC_PENDING_IRQ
25void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val) 25void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
26{ 26{
27 set_balance_irq_affinity(irq, mask_val);
28
27 /* 29 /*
28 * Save these away for later use. Re-progam when the 30 * Save these away for later use. Re-progam when the
29 * interrupt is pending 31 * interrupt is pending
@@ -33,6 +35,7 @@ void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
33#else 35#else
34void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val) 36void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
35{ 37{
38 set_balance_irq_affinity(irq, mask_val);
36 irq_affinity[irq] = mask_val; 39 irq_affinity[irq] = mask_val;
37 irq_desc[irq].handler->set_affinity(irq, mask_val); 40 irq_desc[irq].handler->set_affinity(irq, mask_val);
38} 41}