Messages in this thread |  | | Subject | Re: lots of brief rcu stalls. | From | Joe Perches <> | Date | Wed, 04 Dec 2013 18:36:05 -0800 |
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On Wed, 2013-12-04 at 18:18 -0800, Eric Dumazet wrote: > On Wed, 2013-12-04 at 16:16 -0800, Paul E. McKenney wrote: > > + ULONG_CMP_GE(ACCESS_ONCE(jiffies), rdp->rsp->jiffies_resched)) {
perhaps time_before_eq
> jiffies should not need ACCESS_ONCE(), right ? > > It is one of the few variables marked with volatile keyword.
It does seem redundant
$ git grep -n "ACCESS_ONCE(jiffies)" kernel/rcu/torture.c:1354: jiffies_snap = ACCESS_ONCE(jiffies); kernel/rcu/torture.c:1363: jiffies_snap = ACCESS_ONCE(jiffies); kernel/rcu/tree.c:820: unsigned long j = ACCESS_ONCE(jiffies); kernel/rcu/tree.c:975: j = ACCESS_ONCE(jiffies); kernel/sched/core.c:2324: unsigned long next, now = ACCESS_ONCE(jiffies); kernel/sched/proc.c:536: unsigned long curr_jiffies = ACCESS_ONCE(jiffies); kernel/sched/proc.c:558: unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
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