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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-06-19 10:32:23 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-08-17 07:26:06 -0700 |
| commit | c5ebe66ce774126b888617cab658f6556d23365e (patch) | |
| tree | 357189ecc38674cfd2e88b0422ebd5ce32dc0433 /kernel/rcu | |
| parent | 7414fac050d5e0b64554b902f3955eabbebb6cb2 (diff) | |
| download | op-kernel-dev-c5ebe66ce774126b888617cab658f6556d23365e.zip op-kernel-dev-c5ebe66ce774126b888617cab658f6556d23365e.tar.gz | |
rcu: Add event tracing to ->gp_tasks update at GP start
There is currently event tracing to track when a task is preempted
within a preemptible RCU read-side critical section, and also when that
task subsequently reaches its outermost rcu_read_unlock(), but none
indicating when a new grace period starts when that grace period must
wait on pre-existing readers that have been been preempted at least once
since the beginning of their current RCU read-side critical sections.
This commit therefore adds an event trace at grace-period start in
the case where there are such readers. Note that only the first
reader in the list is traced.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 14ba496..3e3f92e 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -636,10 +636,17 @@ static int rcu_print_task_exp_stall(struct rcu_node *rnp) */ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) { + struct task_struct *t; + RCU_LOCKDEP_WARN(preemptible(), "rcu_preempt_check_blocked_tasks() invoked with preemption enabled!!!\n"); WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)); - if (rcu_preempt_has_tasks(rnp)) + if (rcu_preempt_has_tasks(rnp)) { rnp->gp_tasks = rnp->blkd_tasks.next; + t = container_of(rnp->gp_tasks, struct task_struct, + rcu_node_entry); + trace_rcu_unlock_preempted_task(TPS("rcu_preempt-GPS"), + rnp->gpnum, t->pid); + } WARN_ON_ONCE(rnp->qsmask); } |
