diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-07-26 13:44:00 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-08-30 16:03:45 -0700 |
| commit | fced9c8cfe6bc8a26dbbf785927aa673c83a7a35 (patch) | |
| tree | 04b80df17ce5b236c0aa4fef28a5d1ab6bf889b0 /kernel/rcu/tree.c | |
| parent | d3052109c0bc9e536d17d627ae628ed8ceb6928c (diff) | |
rcu: Avoid resched_cpu() when rescheduling the current CPU
The resched_cpu() interface is quite handy, but it does acquire the
specified CPU's runqueue lock, which does not come for free. This
commit therefore substitutes the following when directing resched_cpu()
at the current CPU:
set_tsk_need_resched(current);
set_preempt_need_resched();
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Diffstat (limited to 'kernel/rcu/tree.c')
| -rw-r--r-- | kernel/rcu/tree.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 96731f62594a..92346ab8077d 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1354,7 +1354,8 @@ static void print_cpu_stall(void) * progress and it could be we're stuck in kernel space without context * switches for an entirely unreasonable amount of time. */ - resched_cpu(smp_processor_id()); + set_tsk_need_resched(current); + set_preempt_need_resched(); } static void check_cpu_stall(struct rcu_data *rdp) @@ -2675,10 +2676,12 @@ static __latent_entropy void rcu_process_callbacks(struct softirq_action *unused WARN_ON_ONCE(!rdp->beenonline); /* Report any deferred quiescent states if preemption enabled. */ - if (!(preempt_count() & PREEMPT_MASK)) + if (!(preempt_count() & PREEMPT_MASK)) { rcu_preempt_deferred_qs(current); - else if (rcu_preempt_need_deferred_qs(current)) - resched_cpu(rdp->cpu); /* Provoke future context switch. */ + } else if (rcu_preempt_need_deferred_qs(current)) { + set_tsk_need_resched(current); + set_preempt_need_resched(); + } /* Update RCU state based on any recent quiescent states. */ rcu_check_quiescent_state(rdp); |