Hello, Sebastian,
Finally getting around to taking another look:
c7e07056a108 EXP rcu: skip the workqueue path on RT
This one makes sense given the later commit setting the
rcu_normal_after_boot kernel parameter. Otherwise, it is
slowing down expedited grace periods for no reason. But
should the check also include rcu_normal_after_boot and
rcu_normal? For example:
if ((IS_ENABLED(CONFIG_PREEMPT_RT_FULL) &&
(rcu_normal || rcu_normal_after_boot) ||
!READ_ONCE(rcu_par_gp_wq) ||
rcu_scheduler_active != RCU_SCHEDULER_RUNNING ||
rcu_is_last_leaf_node(rnp)) {
Alternatively, one approach would be to take the kernel
parameters out in -rt:
static int rcu_normal_after_boot =
IS_ENABLED(CONFIG_PREEMPT_RT_FULL);
#ifndef CONFIG_PREEMPT_RT_FULL
module_param(rcu_normal_after_boot, int, 0);
#endif
And similar for rcu_normal and rcu_expedited.
Or is there some reason to allow run-time expedited grace
periods in CONFIG_PREEMPT_RT_FULL=y kernels?
d1f52391bd8a rcu: Disable RCU_FAST_NO_HZ on RT
Looks good. More complexity could be added if too many people
get themselves in trouble via "select RCU_FAST_NO_HZ".
42b346870326 rcu: make RCU_BOOST default on RT
To avoid complaints about this showing up when people don't
expected, could you please instead "select RCU_BOOST" in
the Kconfig definition of PREEMPT_RT_FULL?
Or do people really want to be able to disable boosting?
457c1b0d9c0e sched: Do not account rcu_preempt_depth on RT in might_sleep()
The idea behind this one is to avoid false-positive complaints
about -rt's sleeping spinlocks, correct?
7ee13e640b01 rbtree: don't include the rcu header
c9b0c9b87081 rtmutex: annotate sleeping lock context
No specific comments.
7912d002ebf9 rcu: Eliminate softirq processing from rcutree
This hasn't caused any problems in -rcu from what I can see.
I am therefore planning to submit the -rcu variant of this to
mainline during the next merge window.
f06d34ebdbbb srcu: Remove srcu_queue_delayed_work_on()
Looks plausible. I will check more carefully for mainline.
aeb04e894cc9 srcu: replace local_irqsave() with a locallock
e48989b033ad irqwork: push most work into softirq context
These look to still be -rt only.
Thanx, Paul
