From 05b0c3b7b05471a6d53300cf6d7d88ee66eff7ed Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 4 Aug 2011 11:10:24 -0400 Subject: [PATCH] rcu: Prevent early boot set_need_resched() from __rcu_pending() There isn't a whole lot of point in poking the scheduler before there are other tasks to switch to. This commit therefore adds a check for rcu_scheduler_fully_active in __rcu_pending() to suppress any pre-scheduler calls to set_need_resched(). The downside of this approach is additional runtime overhead in a reasonably hot code path. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index ba06207..9c8a3f9 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1671,7 +1671,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) check_cpu_stall(rsp, rdp); /* Is the RCU core waiting for a quiescent state from this CPU? */ - if (rdp->qs_pending && !rdp->passed_quiesc) { + if (rcu_scheduler_fully_active && rdp->qs_pending && !rdp->passed_quiesc) { /* * If force_quiescent_state() coming soon and this CPU -- 1.7.6