From bde6c3aa993066acb0d6ce32ecabe03b9d5df92d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 1 Jul 2014 11:26:57 -0700 Subject: rcu: Provide cond_resched_rcu_qs() to force quiescent states in long loops RCU-tasks requires the occasional voluntary context switch from CPU-bound in-kernel tasks. In some cases, this requires instrumenting cond_resched(). However, there is some reluctance to countenance unconditionally instrumenting cond_resched() (see http://lwn.net/Articles/603252/), so this commit creates a separate cond_resched_rcu_qs() that may be used in place of cond_resched() in locations prone to long-duration in-kernel looping. This commit currently instruments only RCU-tasks. Future possibilities include also instrumenting RCU, RCU-bh, and RCU-sched in order to reduce IPI usage. Signed-off-by: Paul E. McKenney --- mm/mlock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/mlock.c') diff --git a/mm/mlock.c b/mm/mlock.c index ce84cb0b83ef..ab3150c26711 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -789,7 +789,7 @@ static int do_mlockall(int flags) /* Ignore errors */ mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags); - cond_resched(); + cond_resched_rcu_qs(); } out: return 0; -- cgit v1.2.3-58-ga151