Revision - 00cc163 - sched: access local runqueue directly in single_task_running - origin: https://github.com/torvalds/linux

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27 March 2024, 02:37:15 UTC

Revision 00cc1633816de8c95f337608a1ea64e228faf771 authored by Dominik Dingel on 18 September 2015, 09:27:45 UTC, committed by Paolo Bonzini on 18 September 2015, 11:47:59 UTC

sched: access local runqueue directly in single_task_running

Commit 2ee507c47293 ("sched: Add function single_task_running to let a task
check if it is the only task running on a cpu") referenced the current
runqueue with the smp_processor_id.  When CONFIG_DEBUG_PREEMPT is enabled,
that is only allowed if preemption is disabled or the currrent task is
bound to the local cpu (e.g. kernel worker).

With commit f78195129963 ("kvm: add halt_poll_ns module parameter") KVM
calls single_task_running. If CONFIG_DEBUG_PREEMPT is enabled that
generates a lot of kernel messages.

To avoid adding preemption in that cases, as it would limit the usefulness,
we change single_task_running to access directly the cpu local runqueue.

Cc: Tim Chen <tim.c.chen@linux.intel.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Fixes: 2ee507c472939db4b146d545352b8a7c79ef47f8
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 parent efe4d36

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Tip revision: 00cc1633816de8c95f337608a1ea64e228faf771 authored by Dominik Dingel on 18 September 2015, 09:27:45 UTC
sched: access local runqueue directly in single_task_running

Tip revision: 00cc163

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sched: access local runqueue directly in single_task_running

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