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authorZhang Yanmin <yanmin.zhang@intel.com>2006-06-23 02:04:22 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-23 07:42:57 -0700
commit1b61b910e99059abdd54c93aa70e84e076e33d16 (patch)
treefe2cd431dc39521a0f2d30e22c9bd3eb3e1bc317 /include/linux/irq.h
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 'include/linux/irq.h')
-rw-r--r--include/linux/irq.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 42c9cd562860..e8a07e75e4fb 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -164,6 +164,14 @@ static inline void set_irq_info(int irq, cpumask_t mask)
#endif // CONFIG_SMP
+#ifdef CONFIG_IRQBALANCE
+extern void set_balance_irq_affinity(unsigned int irq, cpumask_t mask);
+#else
+static inline void set_balance_irq_affinity(unsigned int irq, cpumask_t mask)
+{
+}
+#endif
+
extern int no_irq_affinity;
extern int noirqdebug_setup(char *str);