Messages in this thread Patch in this message | | | Date | Fri, 11 May 2007 17:49:27 +0900 | From | Satoru Takeuchi <> | Subject | [PATCH 2/2] cpu hotplug: fix ksoftirqd termination on cpu hotplug with naughty realtime process |
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Fix ksoftirqd termination on cpu hotplug with naughty real time process.
Assuming the following case:
- Try to hot remove CPU2 from CPU1. - There is a real time process on CPU2, and that process doesn't sleep at all. - That rt process and ksoftirqd/2 is migrated to the CPU0
Then ksoftirqd/2 can't stop becasue that rt process runs everlastingly on CPU0, and CPU1 waiting the ksoftirqd/2's termination hangs up. To fix this problem, set the priority of ksoftirqd/2 to max one before kthread_stop().
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Index: linux-2.6.21/kernel/softirq.c =================================================================== --- linux-2.6.21.orig/kernel/softirq.c 2007-05-11 13:45:34.000000000 +0900 +++ linux-2.6.21/kernel/softirq.c 2007-05-11 17:19:12.000000000 +0900 @@ -590,6 +590,7 @@ static int __cpuinit cpu_callback(struct { int hotcpu = (unsigned long)hcpu; struct task_struct *p; + struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; switch (action) { case CPU_UP_PREPARE: @@ -614,6 +615,7 @@ static int __cpuinit cpu_callback(struct case CPU_DEAD: p = per_cpu(ksoftirqd, hotcpu); per_cpu(ksoftirqd, hotcpu) = NULL; + sched_setscheduler(p, SCHED_FIFO, ¶m); kthread_stop(p); takeover_tasklets(hotcpu); break; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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