rcu: Allow for smp_call_function() running callbacks from idle

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Current RCU hard relies on smp_call_function() callbacks running from
interrupt context. A pending optimization is going to break that, it
will allow idle CPUs to run the callbacks from the idle loop. This
avoids raising the IPI on the requesting CPU and avoids handling an
exception on the receiving CPU.

Change rcu_is_cpu_rrupt_from_idle() to also accept task context,
provided it is the idle task.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Link: https://lore.kernel.org/r/20200527171236.GC706495@hirez.programming.kicks-ass.net

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Peter Zijlstra 2020-05-27 19:12:36 +02:00 • committed by Ingo Molnar

parent b1fcf9b83c

commit 806f04e9fd

1 changed files with 19 additions and 6 deletions

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kernel/rcu/tree.c

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