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| 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_exp.h | |
| parent | d3052109c0bc9e536d17d627ae628ed8ceb6928c (diff) | |
| download | linux-fced9c8cfe6bc8a26dbbf785927aa673c83a7a35.tar.bz2 | |
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_exp.h')
| -rw-r--r-- | kernel/rcu/tree_exp.h | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 78553a8fa3c6..030df96e0d3c 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -672,7 +672,8 @@ static void sync_rcu_exp_handler(void *unused) rcu_report_exp_rdp(rdp); } else { rdp->deferred_qs = true; - resched_cpu(rdp->cpu); + set_tsk_need_resched(t); + set_preempt_need_resched(); } return; } @@ -710,15 +711,16 @@ static void sync_rcu_exp_handler(void *unused) * because we are in an interrupt handler, which will cause that * function to take an early exit without doing anything. * - * Otherwise, use resched_cpu() to force a context switch after - * the CPU enables everything. + * Otherwise, force a context switch after the CPU enables everything. */ rdp->deferred_qs = true; if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) || - WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs())) + WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs())) { rcu_preempt_deferred_qs(t); - else - resched_cpu(rdp->cpu); + } else { + set_tsk_need_resched(t); + set_preempt_need_resched(); + } } /* PREEMPT=y, so no PREEMPT=n expedited grace period to clean up after. */ @@ -779,7 +781,8 @@ static void sync_sched_exp_handler(void *unused) __this_cpu_write(rcu_data.cpu_no_qs.b.exp, true); /* Store .exp before .rcu_urgent_qs. */ smp_store_release(this_cpu_ptr(&rcu_dynticks.rcu_urgent_qs), true); - resched_cpu(smp_processor_id()); + set_tsk_need_resched(current); + set_preempt_need_resched(); } /* Send IPI for expedited cleanup if needed at end of CPU-hotplug operation. */ |