diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-06-25 19:03:16 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-07-17 14:58:56 -0700 |
| commit | 29fd930940193a9a035a75a3847457160d65559a (patch) | |
| tree | 7e59baa7e75ddb46b51b35f2c0e06815ecd47ad1 /kernel/rcu/tree.c | |
| parent | 7fd0ddc5bf1ab5259c80a53a01984e13befd658b (diff) | |
rcu: Use funnel locking for synchronize_rcu_expedited()'s polling loop
This commit gets rid of synchronize_rcu_expedited()'s mutex_trylock()
polling loop in favor of the funnel-locking scheme that was abstracted
from synchronize_sched_expedited().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/tree.c')
| -rw-r--r-- | kernel/rcu/tree.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 094ed8ff82b4..338ea61929bd 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3309,9 +3309,9 @@ static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s) return rcu_seq_done(&rsp->expedited_sequence, s); } -/* Common code for synchronize_sched_expedited() work-done checking. */ -static bool sync_sched_exp_wd(struct rcu_state *rsp, struct rcu_node *rnp, - atomic_long_t *stat, unsigned long s) +/* Common code for synchronize_{rcu,sched}_expedited() work-done checking. */ +static bool sync_exp_work_done(struct rcu_state *rsp, struct rcu_node *rnp, + atomic_long_t *stat, unsigned long s) { if (rcu_exp_gp_seq_done(rsp, s)) { if (rnp) @@ -3319,7 +3319,6 @@ static bool sync_sched_exp_wd(struct rcu_state *rsp, struct rcu_node *rnp, /* Ensure test happens before caller kfree(). */ smp_mb__before_atomic(); /* ^^^ */ atomic_long_inc(stat); - put_online_cpus(); return true; } return false; @@ -3345,14 +3344,14 @@ static struct rcu_node *exp_funnel_lock(struct rcu_state *rsp, unsigned long s) */ rnp0 = per_cpu_ptr(rsp->rda, raw_smp_processor_id())->mynode; for (; rnp0 != NULL; rnp0 = rnp0->parent) { - if (sync_sched_exp_wd(rsp, rnp1, &rsp->expedited_workdone1, s)) + if (sync_exp_work_done(rsp, rnp1, &rsp->expedited_workdone1, s)) return NULL; mutex_lock(&rnp0->exp_funnel_mutex); if (rnp1) mutex_unlock(&rnp1->exp_funnel_mutex); rnp1 = rnp0; } - if (sync_sched_exp_wd(rsp, rnp1, &rsp->expedited_workdone2, s)) + if (sync_exp_work_done(rsp, rnp1, &rsp->expedited_workdone2, s)) return NULL; return rnp1; } @@ -3402,8 +3401,10 @@ void synchronize_sched_expedited(void) WARN_ON_ONCE(cpu_is_offline(raw_smp_processor_id())); rnp = exp_funnel_lock(rsp, s); - if (rnp == NULL) + if (rnp == NULL) { + put_online_cpus(); return; /* Someone else did our work for us. */ + } rcu_exp_gp_seq_start(rsp); |