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| author |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-12-17 08:35:02 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-01-15 23:33:15 -0800 |
| commit | fb81a44b88e6173ed0f6e9d6a1afa5305fb63f6e (patch) | |
| tree | faa68798164b89dd6d37a9a591e62e9dfc7afdad /kernel/rcu | |
| parent | rcu: Make cond_resched_rcu_qs() apply to normal RCU flavors (diff) | |
| download | linux-dev-fb81a44b88e6173ed0f6e9d6a1afa5305fb63f6e.tar.xz linux-dev-fb81a44b88e6173ed0f6e9d6a1afa5305fb63f6e.zip | |
rcu: Add GP-kthread-starvation checks to CPU stall warnings
This commit adds a message that is printed if the relevant grace-period
kthread has not been able to run for the two seconds preceding the
stall warning. (The two seconds is double the maximum interval between
successive bouts of quiescent-state forcing.)
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index cb00e038c2f2..e335f33d0b9f 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1073,6 +1073,21 @@ static void record_gp_stall_check_time(struct rcu_state *rsp) } /* + * Complain about starvation of grace-period kthread. + */ +static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp) +{ + unsigned long gpa; + unsigned long j; + + j = jiffies; + gpa = ACCESS_ONCE(rsp->gp_activity); + if (j - gpa > 2 * HZ) + pr_err("%s kthread starved for %ld jiffies!\n", + rsp->name, j - gpa); +} + +/* * Dump stacks of all tasks running on stalled CPUs. */ static void rcu_dump_cpu_stacks(struct rcu_state *rsp) @@ -1169,9 +1184,10 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) } /* Complain about tasks blocking the grace period. */ - rcu_print_detail_task_stall(rsp); + rcu_check_gp_kthread_starvation(rsp); + force_quiescent_state(rsp); /* Kick them all. */ } @@ -1196,6 +1212,9 @@ static void print_cpu_stall(struct rcu_state *rsp) pr_cont(" (t=%lu jiffies g=%ld c=%ld q=%lu)\n", jiffies - rsp->gp_start, (long)rsp->gpnum, (long)rsp->completed, totqlen); + + rcu_check_gp_kthread_starvation(rsp); + rcu_dump_cpu_stacks(rsp); raw_spin_lock_irqsave(&rnp->lock, flags); |