From: Frederic Weisbecker <[email protected]> If we enqueue an rcu callback, we need the CPU tick to stay alive until we take care of those by completing the appropriate grace period.
Thus, when we call_rcu(), send a self IPI that checks rcu_needs_cpu() so that we restore a periodic tick behaviour that can take care of everything. Signed-off-by: Frederic Weisbecker <[email protected]> Cc: Alessio Igor Bogani <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Avi Kivity <[email protected]> Cc: Chris Metcalf <[email protected]> Cc: Christoph Lameter <[email protected]> Cc: Daniel Lezcano <[email protected]> Cc: Geoff Levand <[email protected]> Cc: Gilad Ben Yossef <[email protected]> Cc: Hakan Akkan <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Kevin Hilman <[email protected]> Cc: Max Krasnyansky <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephen Hemminger <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Sven-Thorsten Dietrich <[email protected]> Cc: Thomas Gleixner <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> --- kernel/rcutree.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 21664a3..7dce432 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -2081,6 +2081,13 @@ static void invoke_rcu_core(void) static void __call_rcu_core(struct rcu_state *rsp, struct rcu_data *rdp, struct rcu_head *head, unsigned long flags) { + /* Restart the timer if needed to handle the callbacks */ + if (cpuset_adaptive_nohz()) { + /* Make updates on nxtlist visible to self IPI */ + barrier(); + smp_cpuset_update_nohz(smp_processor_id()); + } + /* * If called from an extended quiescent state, invoke the RCU * core in order to force a re-evaluation of RCU's idleness. -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
