diff options
| author | Paul E. McKenney | 2019-08-04 13:17:35 -0700 |
|---|---|---|
| committer | Paul E. McKenney | 2019-10-05 10:46:05 -0700 |
| commit | 79ba7ff5a9925f5c170f51ed7a96d1475eb6c27f (patch) | |
| tree | bbc1dd08082d1b70a578c253ca1759ca2d61a4e5 | |
| parent | 96926686deab853bcacf887501f4ed958e38666b (diff) | |
rcutorture: Emulate dyntick aspect of userspace nohz_full sojourn
During an actual call_rcu() flood, there would be frequent trips to
userspace (in-kernel call_rcu() floods must be otherwise housebroken).
Userspace execution on nohz_full CPUs implies an RCU dyntick idle/not-idle
transition pair, so this commit adds emulation of that pair.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
| -rw-r--r-- | include/linux/rcutiny.h | 1 | ||||
| -rw-r--r-- | kernel/rcu/rcutorture.c | 11 | ||||
| -rw-r--r-- | kernel/rcu/tree.c | 1 |
3 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 9bf1dfe7781f..37b6f0c2b79d 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -84,6 +84,7 @@ static inline void rcu_scheduler_starting(void) { } #endif /* #else #ifndef CONFIG_SRCU */ static inline void rcu_end_inkernel_boot(void) { } static inline bool rcu_is_watching(void) { return true; } +static inline void rcu_momentary_dyntick_idle(void) { } /* Avoid RCU read-side critical sections leaking across. */ static inline void rcu_all_qs(void) { barrier(); } diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index ab61f5c1353b..49ad88765ed2 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1761,6 +1761,11 @@ static unsigned long rcu_torture_fwd_prog_cbfree(void) kfree(rfcp); freed++; rcu_torture_fwd_prog_cond_resched(freed); + if (tick_nohz_full_enabled()) { + local_irq_save(flags); + rcu_momentary_dyntick_idle(); + local_irq_restore(flags); + } } return freed; } @@ -1835,6 +1840,7 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries) static void rcu_torture_fwd_prog_cr(void) { unsigned long cver; + unsigned long flags; unsigned long gps; int i; long n_launders; @@ -1894,6 +1900,11 @@ static void rcu_torture_fwd_prog_cr(void) } cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); + if (tick_nohz_full_enabled()) { + local_irq_save(flags); + rcu_momentary_dyntick_idle(); + local_irq_restore(flags); + } } stoppedat = jiffies; n_launders_cb_snap = READ_ONCE(n_launders_cb); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 7c67ea561b36..66354ef776aa 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -375,6 +375,7 @@ void rcu_momentary_dyntick_idle(void) WARN_ON_ONCE(!(special & RCU_DYNTICK_CTRL_CTR)); rcu_preempt_deferred_qs(current); } +EXPORT_SYMBOL_GPL(rcu_momentary_dyntick_idle); /** * rcu_is_cpu_rrupt_from_idle - see if interrupted from idle |