diff options
Diffstat (limited to 'kernel/rcu/tree.c')
| -rw-r--r-- | kernel/rcu/tree.c | 58 |
1 files changed, 54 insertions, 4 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index e45097fc39fa..4b6594c7db58 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3369,16 +3369,65 @@ static struct rcu_node *exp_funnel_lock(struct rcu_state *rsp, unsigned long s) return rnp1; } +/* Invoked on each online non-idle CPU for expedited quiescent state. */ static int synchronize_sched_expedited_cpu_stop(void *data) { - struct rcu_state *rsp = data; + struct rcu_data *rdp = data; + struct rcu_state *rsp = rdp->rsp; /* We are here: If we are last, do the wakeup. */ + rdp->exp_done = true; if (atomic_dec_and_test(&rsp->expedited_need_qs)) wake_up(&rsp->expedited_wq); return 0; } +static void synchronize_sched_expedited_wait(struct rcu_state *rsp) +{ + int cpu; + unsigned long jiffies_stall; + unsigned long jiffies_start; + struct rcu_data *rdp; + int ret; + + jiffies_stall = rcu_jiffies_till_stall_check(); + jiffies_start = jiffies; + + for (;;) { + ret = wait_event_interruptible_timeout( + rsp->expedited_wq, + !atomic_read(&rsp->expedited_need_qs), + jiffies_stall); + if (ret > 0) + return; + if (ret < 0) { + /* Hit a signal, disable CPU stall warnings. */ + wait_event(rsp->expedited_wq, + !atomic_read(&rsp->expedited_need_qs)); + return; + } + pr_err("INFO: %s detected expedited stalls on CPUs: {", + rsp->name); + for_each_online_cpu(cpu) { + rdp = per_cpu_ptr(rsp->rda, cpu); + + if (rdp->exp_done) + continue; + pr_cont(" %d", cpu); + } + pr_cont(" } %lu jiffies s: %lu\n", + jiffies - jiffies_start, rsp->expedited_sequence); + for_each_online_cpu(cpu) { + rdp = per_cpu_ptr(rsp->rda, cpu); + + if (rdp->exp_done) + continue; + dump_cpu_task(cpu); + } + jiffies_stall = 3 * rcu_jiffies_till_stall_check() + 3; + } +} + /** * synchronize_sched_expedited - Brute-force RCU-sched grace period * @@ -3428,19 +3477,20 @@ void synchronize_sched_expedited(void) struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu); + rdp->exp_done = false; + /* Skip our CPU and any idle CPUs. */ if (raw_smp_processor_id() == cpu || !(atomic_add_return(0, &rdtp->dynticks) & 0x1)) continue; atomic_inc(&rsp->expedited_need_qs); stop_one_cpu_nowait(cpu, synchronize_sched_expedited_cpu_stop, - rsp, &rdp->exp_stop_work); + rdp, &rdp->exp_stop_work); } /* Remove extra count and, if necessary, wait for CPUs to stop. */ if (!atomic_dec_and_test(&rsp->expedited_need_qs)) - wait_event(rsp->expedited_wq, - !atomic_read(&rsp->expedited_need_qs)); + synchronize_sched_expedited_wait(rsp); rcu_exp_gp_seq_end(rsp); mutex_unlock(&rnp->exp_funnel_mutex); |