diff options
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/srcu.c | 2 | ||||
| -rw-r--r-- | kernel/rcu/tree.c | 6 | ||||
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 6 | ||||
| -rw-r--r-- | kernel/rcu/update.c | 12 |
4 files changed, 25 insertions, 1 deletions
diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c index a63a1ea5a41b..9b9cdd549caa 100644 --- a/kernel/rcu/srcu.c +++ b/kernel/rcu/srcu.c @@ -489,7 +489,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) */ void synchronize_srcu(struct srcu_struct *sp) { - __synchronize_srcu(sp, rcu_gp_is_expedited() + __synchronize_srcu(sp, (rcu_gp_is_expedited() && !rcu_gp_is_normal()) ? SYNCHRONIZE_SRCU_EXP_TRYCOUNT : SYNCHRONIZE_SRCU_TRYCOUNT); } diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 6a652d1f3d7f..489992997c06 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3841,6 +3841,12 @@ void synchronize_sched_expedited(void) if (rcu_blocking_is_gp()) return; + /* If expedited grace periods are prohibited, fall back to normal. */ + if (rcu_gp_is_normal()) { + wait_rcu_gp(call_rcu_sched); + return; + } + /* Take a snapshot of the sequence number. */ s = rcu_exp_gp_seq_snap(rsp); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 57ba873d2f18..d45df3781551 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -746,6 +746,12 @@ void synchronize_rcu_expedited(void) struct rcu_state *rsp = rcu_state_p; unsigned long s; + /* If expedited grace periods are prohibited, fall back to normal. */ + if (rcu_gp_is_normal()) { + wait_rcu_gp(call_rcu); + return; + } + s = rcu_exp_gp_seq_snap(rsp); rnp_unlock = exp_funnel_lock(rsp, s); diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 5f748c5a40f0..8fccda3a794d 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -61,6 +61,7 @@ MODULE_ALIAS("rcupdate"); #define MODULE_PARAM_PREFIX "rcupdate." module_param(rcu_expedited, int, 0); +module_param(rcu_normal, int, 0); #if defined(CONFIG_DEBUG_LOCK_ALLOC) && defined(CONFIG_PREEMPT_COUNT) /** @@ -113,6 +114,17 @@ EXPORT_SYMBOL(rcu_read_lock_sched_held); #ifndef CONFIG_TINY_RCU +/* + * Should expedited grace-period primitives always fall back to their + * non-expedited counterparts? Intended for use within RCU. Note + * that if the user specifies both rcu_expedited and rcu_normal, then + * rcu_normal wins. + */ +bool rcu_gp_is_normal(void) +{ + return READ_ONCE(rcu_normal); +} + static atomic_t rcu_expedited_nesting = ATOMIC_INIT(IS_ENABLED(CONFIG_RCU_EXPEDITE_BOOT) ? 1 : 0); |