The patch titled
cpu hotplug: fix ksoftirqd termination on cpu hotplug with naughty realtime process
has been removed from the -mm tree. Its filename was
cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: cpu hotplug: fix ksoftirqd termination on cpu hotplug with naughty realtime process
From: Satoru Takeuchi <takeuchi_satoru@xxxxxxxxxxxxxx>
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().
[akpm@xxxxxxxxxxxxxxxxxxxx: fix warning]
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@xxxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
Cc: Gautham R Shenoy <ego@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/softirq.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff -puN kernel/softirq.c~cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process kernel/softirq.c
--- a/kernel/softirq.c~cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process
+++ a/kernel/softirq.c
@@ -614,12 +614,16 @@ static int __cpuinit cpu_callback(struct
kthread_bind(per_cpu(ksoftirqd, hotcpu),
any_online_cpu(cpu_online_map));
case CPU_DEAD:
- case CPU_DEAD_FROZEN:
+ case CPU_DEAD_FROZEN: {
+ struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+
p = per_cpu(ksoftirqd, hotcpu);
per_cpu(ksoftirqd, hotcpu) = NULL;
+ sched_setscheduler(p, SCHED_FIFO, ¶m);
kthread_stop(p);
takeover_tasklets(hotcpu);
break;
+ }
#endif /* CONFIG_HOTPLUG_CPU */
}
return NOTIFY_OK;
_
Patches currently in -mm which might be from takeuchi_satoru@xxxxxxxxxxxxxx are
origin.patch
-
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