[PATCH] softirq: Avoid stack switch from ksoftirqd

From: Thomas Gleixner
Date: Wed Feb 02 2011 - 11:11:17 EST


ksoftirqd() calls do_softirq() which switches stacks on several
architectures. That makes no sense at all. ksoftirqd's stack is
sufficient.

Call __do_softirq() directly.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/softirq.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

Index: linux-2.6-tip/kernel/softirq.c
===================================================================
--- linux-2.6-tip.orig/kernel/softirq.c
+++ linux-2.6-tip/kernel/softirq.c
@@ -738,7 +738,10 @@ static int run_ksoftirqd(void * __bind_c
don't process */
if (cpu_is_offline((long)__bind_cpu))
goto wait_to_die;
- do_softirq();
+ local_irq_disable();
+ if (local_softirq_pending())
+ __do_softirq();
+ local_irq_enable();
preempt_enable_no_resched();
cond_resched();
preempt_disable();
--
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